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| author | Sayan Nandan <17377258+sntdevco@users.noreply.github.com> | 2019-08-09 13:01:05 +0530 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-08-09 13:01:05 +0530 |
| commit | fb3a01354ffecc41d7a189e4dd225d706387a522 (patch) | |
| tree | 41492dfe93f1dccba847dadb56ac6aa079edaaa9 /src/liballoc | |
| parent | 33445aea509cadcd715009c79795d289268daa7c (diff) | |
| parent | 5aa3d9a7b5d3a46a7f158e8881146331a6bc9243 (diff) | |
| download | rust-fb3a01354ffecc41d7a189e4dd225d706387a522.tar.gz rust-fb3a01354ffecc41d7a189e4dd225d706387a522.zip | |
Merge pull request #1 from rust-lang/master
Merge recent changes into master
Diffstat (limited to 'src/liballoc')
46 files changed, 4279 insertions, 2519 deletions
diff --git a/src/liballoc/Cargo.toml b/src/liballoc/Cargo.toml index f6d6c1de8f5..d1119f7b7c0 100644 --- a/src/liballoc/Cargo.toml +++ b/src/liballoc/Cargo.toml @@ -12,11 +12,11 @@ path = "lib.rs" [dependencies] core = { path = "../libcore" } -compiler_builtins = { version = "0.1.0", features = ['rustc-dep-of-std'] } +compiler_builtins = { version = "0.1.10", features = ['rustc-dep-of-std'] } [dev-dependencies] -rand = "0.6" -rand_xorshift = "0.1" +rand = "0.7" +rand_xorshift = "0.2" [[test]] name = "collectionstests" @@ -33,3 +33,4 @@ harness = false [features] compiler-builtins-mem = ['compiler_builtins/mem'] +compiler-builtins-c = ["compiler_builtins/c"] diff --git a/src/liballoc/alloc.rs b/src/liballoc/alloc.rs index f3877e51a66..dc7fd1adc29 100644 --- a/src/liballoc/alloc.rs +++ b/src/liballoc/alloc.rs @@ -10,12 +10,15 @@ use core::usize; #[doc(inline)] pub use core::alloc::*; +#[cfg(test)] +mod tests; + extern "Rust" { // These are the magic symbols to call the global allocator. rustc generates // them from the `#[global_allocator]` attribute if there is one, or uses the // default implementations in libstd (`__rdl_alloc` etc in `src/libstd/alloc.rs`) // otherwise. - #[allocator] + #[rustc_allocator] #[rustc_allocator_nounwind] fn __rust_alloc(size: usize, align: usize) -> *mut u8; #[rustc_allocator_nounwind] @@ -37,6 +40,8 @@ extern "Rust" { /// /// Note: while this type is unstable, the functionality it provides can be /// accessed through the [free functions in `alloc`](index.html#functions). +/// +/// [`Alloc`]: trait.Alloc.html #[unstable(feature = "allocator_api", issue = "32838")] #[derive(Copy, Clone, Default, Debug)] pub struct Global; @@ -54,6 +59,10 @@ pub struct Global; /// /// See [`GlobalAlloc::alloc`]. /// +/// [`Global`]: struct.Global.html +/// [`Alloc`]: trait.Alloc.html +/// [`GlobalAlloc::alloc`]: trait.GlobalAlloc.html#tymethod.alloc +/// /// # Examples /// /// ``` @@ -87,6 +96,10 @@ pub unsafe fn alloc(layout: Layout) -> *mut u8 { /// # Safety /// /// See [`GlobalAlloc::dealloc`]. +/// +/// [`Global`]: struct.Global.html +/// [`Alloc`]: trait.Alloc.html +/// [`GlobalAlloc::dealloc`]: trait.GlobalAlloc.html#tymethod.dealloc #[stable(feature = "global_alloc", since = "1.28.0")] #[inline] pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) { @@ -105,6 +118,10 @@ pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) { /// # Safety /// /// See [`GlobalAlloc::realloc`]. +/// +/// [`Global`]: struct.Global.html +/// [`Alloc`]: trait.Alloc.html +/// [`GlobalAlloc::realloc`]: trait.GlobalAlloc.html#method.realloc #[stable(feature = "global_alloc", since = "1.28.0")] #[inline] pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 { @@ -124,6 +141,10 @@ pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 /// /// See [`GlobalAlloc::alloc_zeroed`]. /// +/// [`Global`]: struct.Global.html +/// [`Alloc`]: trait.Alloc.html +/// [`GlobalAlloc::alloc_zeroed`]: trait.GlobalAlloc.html#method.alloc_zeroed +/// /// # Examples /// /// ``` @@ -226,35 +247,3 @@ pub fn handle_alloc_error(layout: Layout) -> ! { } unsafe { oom_impl(layout) } } - -#[cfg(test)] -mod tests { - extern crate test; - use test::Bencher; - use crate::boxed::Box; - use crate::alloc::{Global, Alloc, Layout, handle_alloc_error}; - - #[test] - fn allocate_zeroed() { - unsafe { - let layout = Layout::from_size_align(1024, 1).unwrap(); - let ptr = Global.alloc_zeroed(layout.clone()) - .unwrap_or_else(|_| handle_alloc_error(layout)); - - let mut i = ptr.cast::<u8>().as_ptr(); - let end = i.add(layout.size()); - while i < end { - assert_eq!(*i, 0); - i = i.offset(1); - } - Global.dealloc(ptr, layout); - } - } - - #[bench] - fn alloc_owned_small(b: &mut Bencher) { - b.iter(|| { - let _: Box<_> = box 10; - }) - } -} diff --git a/src/liballoc/alloc/tests.rs b/src/liballoc/alloc/tests.rs new file mode 100644 index 00000000000..c69f4e49ee1 --- /dev/null +++ b/src/liballoc/alloc/tests.rs @@ -0,0 +1,30 @@ +use super::*; + +extern crate test; +use test::Bencher; +use crate::boxed::Box; + +#[test] +fn allocate_zeroed() { + unsafe { + let layout = Layout::from_size_align(1024, 1).unwrap(); + let ptr = Global.alloc_zeroed(layout.clone()) + .unwrap_or_else(|_| handle_alloc_error(layout)); + + let mut i = ptr.cast::<u8>().as_ptr(); + let end = i.add(layout.size()); + while i < end { + assert_eq!(*i, 0); + i = i.offset(1); + } + Global.dealloc(ptr, layout); + } +} + +#[bench] +#[cfg(not(miri))] // Miri does not support benchmarks +fn alloc_owned_small(b: &mut Bencher) { + b.iter(|| { + let _: Box<_> = box 10; + }) +} diff --git a/src/liballoc/benches/btree/set.rs b/src/liballoc/benches/btree/set.rs index 08e1db5fbb7..6357ea3ea11 100644 --- a/src/liballoc/benches/btree/set.rs +++ b/src/liballoc/benches/btree/set.rs @@ -3,59 +3,49 @@ use std::collections::BTreeSet; use rand::{thread_rng, Rng}; use test::{black_box, Bencher}; -fn random(n1: u32, n2: u32) -> [BTreeSet<usize>; 2] { +fn random(n: usize) -> BTreeSet<usize> { let mut rng = thread_rng(); - let mut set1 = BTreeSet::new(); - let mut set2 = BTreeSet::new(); - for _ in 0..n1 { - let i = rng.gen::<usize>(); - set1.insert(i); + let mut set = BTreeSet::new(); + while set.len() < n { + set.insert(rng.gen()); } - for _ in 0..n2 { - let i = rng.gen::<usize>(); - set2.insert(i); - } - [set1, set2] + assert_eq!(set.len(), n); + set } -fn staggered(n1: u32, n2: u32) -> [BTreeSet<u32>; 2] { - let mut even = BTreeSet::new(); - let mut odd = BTreeSet::new(); - for i in 0..n1 { - even.insert(i * 2); - } - for i in 0..n2 { - odd.insert(i * 2 + 1); +fn neg(n: usize) -> BTreeSet<i32> { + let mut set = BTreeSet::new(); + for i in -(n as i32)..=-1 { + set.insert(i); } - [even, odd] + assert_eq!(set.len(), n); + set } -fn neg_vs_pos(n1: u32, n2: u32) -> [BTreeSet<i32>; 2] { - let mut neg = BTreeSet::new(); - let mut pos = BTreeSet::new(); - for i in -(n1 as i32)..=-1 { - neg.insert(i); - } - for i in 1..=(n2 as i32) { - pos.insert(i); +fn pos(n: usize) -> BTreeSet<i32> { + let mut set = BTreeSet::new(); + for i in 1..=(n as i32) { + set.insert(i); } - [neg, pos] + assert_eq!(set.len(), n); + set } -fn pos_vs_neg(n1: u32, n2: u32) -> [BTreeSet<i32>; 2] { - let mut neg = BTreeSet::new(); - let mut pos = BTreeSet::new(); - for i in -(n1 as i32)..=-1 { - neg.insert(i); - } - for i in 1..=(n2 as i32) { - pos.insert(i); + +fn stagger(n1: usize, factor: usize) -> [BTreeSet<u32>; 2] { + let n2 = n1 * factor; + let mut sets = [BTreeSet::new(), BTreeSet::new()]; + for i in 0..(n1 + n2) { + let b = i % (factor + 1) != 0; + sets[b as usize].insert(i as u32); } - [pos, neg] + assert_eq!(sets[0].len(), n1); + assert_eq!(sets[1].len(), n2); + sets } -macro_rules! set_intersection_bench { - ($name: ident, $sets: expr) => { +macro_rules! set_bench { + ($name: ident, $set_func: ident, $result_func: ident, $sets: expr) => { #[bench] pub fn $name(b: &mut Bencher) { // setup @@ -63,26 +53,36 @@ macro_rules! set_intersection_bench { // measure b.iter(|| { - let x = sets[0].intersection(&sets[1]).count(); + let x = sets[0].$set_func(&sets[1]).$result_func(); black_box(x); }) } }; } -set_intersection_bench! {intersect_random_100, random(100, 100)} -set_intersection_bench! {intersect_random_10k, random(10_000, 10_000)} -set_intersection_bench! {intersect_random_10_vs_10k, random(10, 10_000)} -set_intersection_bench! {intersect_random_10k_vs_10, random(10_000, 10)} -set_intersection_bench! {intersect_staggered_100, staggered(100, 100)} -set_intersection_bench! {intersect_staggered_10k, staggered(10_000, 10_000)} -set_intersection_bench! {intersect_staggered_10_vs_10k, staggered(10, 10_000)} -set_intersection_bench! {intersect_staggered_10k_vs_10, staggered(10_000, 10)} -set_intersection_bench! {intersect_neg_vs_pos_100, neg_vs_pos(100, 100)} -set_intersection_bench! {intersect_neg_vs_pos_10k, neg_vs_pos(10_000, 10_000)} -set_intersection_bench! {intersect_neg_vs_pos_10_vs_10k,neg_vs_pos(10, 10_000)} -set_intersection_bench! {intersect_neg_vs_pos_10k_vs_10,neg_vs_pos(10_000, 10)} -set_intersection_bench! {intersect_pos_vs_neg_100, pos_vs_neg(100, 100)} -set_intersection_bench! {intersect_pos_vs_neg_10k, pos_vs_neg(10_000, 10_000)} -set_intersection_bench! {intersect_pos_vs_neg_10_vs_10k,pos_vs_neg(10, 10_000)} -set_intersection_bench! {intersect_pos_vs_neg_10k_vs_10,pos_vs_neg(10_000, 10)} +set_bench! {intersection_100_neg_vs_100_pos, intersection, count, [neg(100), pos(100)]} +set_bench! {intersection_100_neg_vs_10k_pos, intersection, count, [neg(100), pos(10_000)]} +set_bench! {intersection_100_pos_vs_100_neg, intersection, count, [pos(100), neg(100)]} +set_bench! {intersection_100_pos_vs_10k_neg, intersection, count, [pos(100), neg(10_000)]} +set_bench! {intersection_10k_neg_vs_100_pos, intersection, count, [neg(10_000), pos(100)]} +set_bench! {intersection_10k_neg_vs_10k_pos, intersection, count, [neg(10_000), pos(10_000)]} +set_bench! {intersection_10k_pos_vs_100_neg, intersection, count, [pos(10_000), neg(100)]} +set_bench! {intersection_10k_pos_vs_10k_neg, intersection, count, [pos(10_000), neg(10_000)]} +set_bench! {intersection_random_100_vs_100, intersection, count, [random(100), random(100)]} +set_bench! {intersection_random_100_vs_10k, intersection, count, [random(100), random(10_000)]} +set_bench! {intersection_random_10k_vs_100, intersection, count, [random(10_000), random(100)]} +set_bench! {intersection_random_10k_vs_10k, intersection, count, [random(10_000), random(10_000)]} +set_bench! {intersection_staggered_100_vs_100, intersection, count, stagger(100, 1)} +set_bench! {intersection_staggered_10k_vs_10k, intersection, count, stagger(10_000, 1)} +set_bench! {intersection_staggered_100_vs_10k, intersection, count, stagger(100, 100)} +set_bench! {difference_random_100_vs_100, difference, count, [random(100), random(100)]} +set_bench! {difference_random_100_vs_10k, difference, count, [random(100), random(10_000)]} +set_bench! {difference_random_10k_vs_100, difference, count, [random(10_000), random(100)]} +set_bench! {difference_random_10k_vs_10k, difference, count, [random(10_000), random(10_000)]} +set_bench! {difference_staggered_100_vs_100, difference, count, stagger(100, 1)} +set_bench! {difference_staggered_10k_vs_10k, difference, count, stagger(10_000, 1)} +set_bench! {difference_staggered_100_vs_10k, difference, count, stagger(100, 100)} +set_bench! {is_subset_100_vs_100, is_subset, clone, [pos(100), pos(100)]} +set_bench! {is_subset_100_vs_10k, is_subset, clone, [pos(100), pos(10_000)]} +set_bench! {is_subset_10k_vs_100, is_subset, clone, [pos(10_000), pos(100)]} +set_bench! {is_subset_10k_vs_10k, is_subset, clone, [pos(10_000), pos(10_000)]} diff --git a/src/liballoc/benches/slice.rs b/src/liballoc/benches/slice.rs index f17fb8212ce..ef91d801dc7 100644 --- a/src/liballoc/benches/slice.rs +++ b/src/liballoc/benches/slice.rs @@ -186,12 +186,12 @@ const SEED: [u8; 16] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]; fn gen_random(len: usize) -> Vec<u64> { let mut rng = XorShiftRng::from_seed(SEED); - rng.sample_iter(&Standard).take(len).collect() + (&mut rng).sample_iter(&Standard).take(len).collect() } fn gen_random_bytes(len: usize) -> Vec<u8> { let mut rng = XorShiftRng::from_seed(SEED); - rng.sample_iter(&Standard).take(len).collect() + (&mut rng).sample_iter(&Standard).take(len).collect() } fn gen_mostly_ascending(len: usize) -> Vec<u64> { @@ -221,14 +221,14 @@ fn gen_strings(len: usize) -> Vec<String> { let mut v = vec![]; for _ in 0..len { let n = rng.gen::<usize>() % 20 + 1; - v.push(rng.sample_iter(&Alphanumeric).take(n).collect()); + v.push((&mut rng).sample_iter(&Alphanumeric).take(n).collect()); } v } fn gen_big_random(len: usize) -> Vec<[u64; 16]> { let mut rng = XorShiftRng::from_seed(SEED); - rng.sample_iter(&Standard).map(|x| [x; 16]).take(len).collect() + (&mut rng).sample_iter(&Standard).map(|x| [x; 16]).take(len).collect() } macro_rules! sort { diff --git a/src/liballoc/borrow.rs b/src/liballoc/borrow.rs index 74c80a08b12..d5e15b3719c 100644 --- a/src/liballoc/borrow.rs +++ b/src/liballoc/borrow.rs @@ -32,6 +32,7 @@ impl<'a, B: ?Sized> Borrow<B> for Cow<'a, B> /// from any borrow of a given type. #[stable(feature = "rust1", since = "1.0.0")] pub trait ToOwned { + /// The resulting type after obtaining ownership. #[stable(feature = "rust1", since = "1.0.0")] type Owned: Borrow<Self>; @@ -135,7 +136,7 @@ impl<T> ToOwned for T /// Another example showing how to keep `Cow` in a struct: /// /// ``` -/// use std::borrow::{Cow, ToOwned}; +/// use std::borrow::Cow; /// /// struct Items<'a, X: 'a> where [X]: ToOwned<Owned = Vec<X>> { /// values: Cow<'a, [X]>, diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs index 9bce142b483..c92db517cad 100644 --- a/src/liballoc/boxed.rs +++ b/src/liballoc/boxed.rs @@ -1,19 +1,9 @@ //! A pointer type for heap allocation. //! -//! `Box<T>`, casually referred to as a 'box', provides the simplest form of +//! [`Box<T>`], casually referred to as a 'box', provides the simplest form of //! heap allocation in Rust. Boxes provide ownership for this allocation, and //! drop their contents when they go out of scope. //! -//! For non-zero-sized values, a [`Box`] will use the [`Global`] allocator for -//! its allocation. It is valid to convert both ways between a [`Box`] and a -//! raw pointer allocated with the [`Global`] allocator, given that the -//! [`Layout`] used with the allocator is correct for the type. More precisely, -//! a `value: *mut T` that has been allocated with the [`Global`] allocator -//! with `Layout::for_value(&*value)` may be converted into a box using -//! `Box::<T>::from_raw(value)`. Conversely, the memory backing a `value: *mut -//! T` obtained from `Box::<T>::into_raw` may be deallocated using the -//! [`Global`] allocator with `Layout::for_value(&*value)`. -//! //! # Examples //! //! Move a value from the stack to the heap by creating a [`Box`]: @@ -58,18 +48,38 @@ //! //! It wouldn't work. This is because the size of a `List` depends on how many //! elements are in the list, and so we don't know how much memory to allocate -//! for a `Cons`. By introducing a `Box`, which has a defined size, we know how +//! for a `Cons`. By introducing a [`Box<T>`], which has a defined size, we know how //! big `Cons` needs to be. //! +//! # Memory layout +//! +//! For non-zero-sized values, a [`Box`] will use the [`Global`] allocator for +//! its allocation. It is valid to convert both ways between a [`Box`] and a +//! raw pointer allocated with the [`Global`] allocator, given that the +//! [`Layout`] used with the allocator is correct for the type. More precisely, +//! a `value: *mut T` that has been allocated with the [`Global`] allocator +//! with `Layout::for_value(&*value)` may be converted into a box using +//! [`Box::<T>::from_raw(value)`]. Conversely, the memory backing a `value: *mut +//! T` obtained from [`Box::<T>::into_raw`] may be deallocated using the +//! [`Global`] allocator with [`Layout::for_value(&*value)`]. +//! +//! //! [dereferencing]: ../../std/ops/trait.Deref.html //! [`Box`]: struct.Box.html +//! [`Box<T>`]: struct.Box.html +//! [`Box::<T>::from_raw(value)`]: struct.Box.html#method.from_raw +//! [`Box::<T>::into_raw`]: struct.Box.html#method.into_raw +//! [`Global`]: ../alloc/struct.Global.html +//! [`Layout`]: ../alloc/struct.Layout.html +//! [`Layout::for_value(&*value)`]: ../alloc/struct.Layout.html#method.for_value #![stable(feature = "rust1", since = "1.0.0")] use core::any::Any; +use core::array::LengthAtMost32; use core::borrow; use core::cmp::Ordering; -use core::convert::From; +use core::convert::{From, TryFrom}; use core::fmt; use core::future::Future; use core::hash::{Hash, Hasher}; @@ -81,7 +91,7 @@ use core::ops::{ CoerceUnsized, DispatchFromDyn, Deref, DerefMut, Receiver, Generator, GeneratorState }; use core::ptr::{self, NonNull, Unique}; -use core::task::{Waker, Poll}; +use core::task::{Context, Poll}; use crate::vec::Vec; use crate::raw_vec::RawVec; @@ -125,24 +135,38 @@ impl<T: ?Sized> Box<T> { /// /// After calling this function, the raw pointer is owned by the /// resulting `Box`. Specifically, the `Box` destructor will call - /// the destructor of `T` and free the allocated memory. Since the - /// way `Box` allocates and releases memory is unspecified, the - /// only valid pointer to pass to this function is the one taken - /// from another `Box` via the [`Box::into_raw`] function. + /// the destructor of `T` and free the allocated memory. For this + /// to be safe, the memory must have been allocated in accordance + /// with the [memory layout] used by `Box` . + /// + /// # Safety /// /// This function is unsafe because improper use may lead to /// memory problems. For example, a double-free may occur if the /// function is called twice on the same raw pointer. /// - /// [`Box::into_raw`]: struct.Box.html#method.into_raw - /// /// # Examples - /// + /// Recreate a `Box` which was previously converted to a raw pointer + /// using [`Box::into_raw`]: /// ``` /// let x = Box::new(5); /// let ptr = Box::into_raw(x); /// let x = unsafe { Box::from_raw(ptr) }; /// ``` + /// Manually create a `Box` from scratch by using the global allocator: + /// ``` + /// use std::alloc::{alloc, Layout}; + /// + /// unsafe { + /// let ptr = alloc(Layout::new::<i32>()) as *mut i32; + /// *ptr = 5; + /// let x = Box::from_raw(ptr); + /// } + /// ``` + /// + /// [memory layout]: index.html#memory-layout + /// [`Layout`]: ../alloc/struct.Layout.html + /// [`Box::into_raw`]: struct.Box.html#method.into_raw #[stable(feature = "box_raw", since = "1.4.0")] #[inline] pub unsafe fn from_raw(raw: *mut T) -> Self { @@ -155,22 +179,40 @@ impl<T: ?Sized> Box<T> { /// /// After calling this function, the caller is responsible for the /// memory previously managed by the `Box`. In particular, the - /// caller should properly destroy `T` and release the memory. The - /// proper way to do so is to convert the raw pointer back into a - /// `Box` with the [`Box::from_raw`] function. + /// caller should properly destroy `T` and release the memory, taking + /// into account the [memory layout] used by `Box`. The easiest way to + /// do this is to convert the raw pointer back into a `Box` with the + /// [`Box::from_raw`] function, allowing the `Box` destructor to perform + /// the cleanup. /// /// Note: this is an associated function, which means that you have /// to call it as `Box::into_raw(b)` instead of `b.into_raw()`. This /// is so that there is no conflict with a method on the inner type. /// - /// [`Box::from_raw`]: struct.Box.html#method.from_raw - /// /// # Examples - /// + /// Converting the raw pointer back into a `Box` with [`Box::from_raw`] + /// for automatic cleanup: /// ``` - /// let x = Box::new(5); + /// let x = Box::new(String::from("Hello")); /// let ptr = Box::into_raw(x); + /// let x = unsafe { Box::from_raw(ptr) }; /// ``` + /// Manual cleanup by explicitly running the destructor and deallocating + /// the memory: + /// ``` + /// use std::alloc::{dealloc, Layout}; + /// use std::ptr; + /// + /// let x = Box::new(String::from("Hello")); + /// let p = Box::into_raw(x); + /// unsafe { + /// ptr::drop_in_place(p); + /// dealloc(p as *mut u8, Layout::new::<String>()); + /// } + /// ``` + /// + /// [memory layout]: index.html#memory-layout + /// [`Box::from_raw`]: struct.Box.html#method.from_raw #[stable(feature = "box_raw", since = "1.4.0")] #[inline] pub fn into_raw(b: Box<T>) -> *mut T { @@ -182,7 +224,7 @@ impl<T: ?Sized> Box<T> { /// After calling this function, the caller is responsible for the /// memory previously managed by the `Box`. In particular, the /// caller should properly destroy `T` and release the memory. The - /// proper way to do so is to convert the `NonNull<T>` pointer + /// easiest way to do so is to convert the `NonNull<T>` pointer /// into a raw pointer and back into a `Box` with the [`Box::from_raw`] /// function. /// @@ -201,6 +243,10 @@ impl<T: ?Sized> Box<T> { /// fn main() { /// let x = Box::new(5); /// let ptr = Box::into_raw_non_null(x); + /// + /// // Clean up the memory by converting the NonNull pointer back + /// // into a Box and letting the Box be dropped. + /// let x = unsafe { Box::from_raw(ptr.as_ptr()) }; /// } /// ``` #[unstable(feature = "box_into_raw_non_null", issue = "47336")] @@ -212,15 +258,16 @@ impl<T: ?Sized> Box<T> { #[unstable(feature = "ptr_internals", issue = "0", reason = "use into_raw_non_null instead")] #[inline] #[doc(hidden)] - pub fn into_unique(mut b: Box<T>) -> Unique<T> { + pub fn into_unique(b: Box<T>) -> Unique<T> { + let mut unique = b.0; + mem::forget(b); // Box is kind-of a library type, but recognized as a "unique pointer" by // Stacked Borrows. This function here corresponds to "reborrowing to // a raw pointer", but there is no actual reborrow here -- so // without some care, the pointer we are returning here still carries - // the `Uniq` tag. We round-trip through a mutable reference to avoid that. - let unique = unsafe { b.0.as_mut() as *mut T }; - mem::forget(b); - unsafe { Unique::new_unchecked(unique) } + // the tag of `b`, with `Unique` permission. + // We round-trip through a mutable reference to avoid that. + unsafe { Unique::new_unchecked(unique.as_mut() as *mut T) } } /// Consumes and leaks the `Box`, returning a mutable reference, @@ -278,7 +325,7 @@ impl<T: ?Sized> Box<T> { /// This conversion does not allocate on the heap and happens in place. /// /// This is also available via [`From`]. - #[unstable(feature = "box_into_pin", issue = "0")] + #[unstable(feature = "box_into_pin", issue = "62370")] pub fn into_pin(boxed: Box<T>) -> Pin<Box<T>> { // It's not possible to move or replace the insides of a `Pin<Box<T>>` // when `T: !Unpin`, so it's safe to pin it directly without any @@ -325,12 +372,19 @@ impl<T: Clone> Clone for Box<T> { /// ``` /// let x = Box::new(5); /// let y = x.clone(); + /// + /// // The value is the same + /// assert_eq!(x, y); + /// + /// // But they are unique objects + /// assert_ne!(&*x as *const i32, &*y as *const i32); /// ``` #[rustfmt::skip] #[inline] fn clone(&self) -> Box<T> { box { (**self).clone() } } + /// Copies `source`'s contents into `self` without creating a new allocation. /// /// # Examples @@ -338,10 +392,15 @@ impl<T: Clone> Clone for Box<T> { /// ``` /// let x = Box::new(5); /// let mut y = Box::new(10); + /// let yp: *const i32 = &*y; /// /// y.clone_from(&x); /// - /// assert_eq!(*y, 5); + /// // The value is the same + /// assert_eq!(x, y); + /// + /// // And no allocation occurred + /// assert_eq!(yp, &*y); /// ``` #[inline] fn clone_from(&mut self, source: &Box<T>) { @@ -353,11 +412,10 @@ impl<T: Clone> Clone for Box<T> { #[stable(feature = "box_slice_clone", since = "1.3.0")] impl Clone for Box<str> { fn clone(&self) -> Self { - let len = self.len(); - let buf = RawVec::with_capacity(len); + // this makes a copy of the data + let buf: Box<[u8]> = self.as_bytes().into(); unsafe { - ptr::copy_nonoverlapping(self.as_ptr(), buf.ptr(), len); - from_boxed_utf8_unchecked(buf.into_box()) + from_boxed_utf8_unchecked(buf) } } } @@ -504,9 +562,12 @@ impl<T: Copy> From<&[T]> for Box<[T]> { /// println!("{:?}", boxed_slice); /// ``` fn from(slice: &[T]) -> Box<[T]> { - let mut boxed = unsafe { RawVec::with_capacity(slice.len()).into_box() }; - boxed.copy_from_slice(slice); - boxed + let len = slice.len(); + let buf = RawVec::with_capacity(len); + unsafe { + ptr::copy_nonoverlapping(slice.as_ptr(), buf.ptr(), len); + buf.into_box() + } } } @@ -552,6 +613,22 @@ impl From<Box<str>> for Box<[u8]> { } } +#[unstable(feature = "boxed_slice_try_from", issue = "0")] +impl<T, const N: usize> TryFrom<Box<[T]>> for Box<[T; N]> +where + [T; N]: LengthAtMost32, +{ + type Error = Box<[T]>; + + fn try_from(boxed_slice: Box<[T]>) -> Result<Self, Self::Error> { + if boxed_slice.len() == N { + Ok(unsafe { Box::from_raw(Box::into_raw(boxed_slice) as *mut [T; N]) }) + } else { + Err(boxed_slice) + } + } +} + impl Box<dyn Any> { #[inline] #[stable(feature = "rust1", since = "1.0.0")] @@ -672,11 +749,22 @@ impl<I: Iterator + ?Sized> Iterator for Box<I> { (**self).nth(n) } } + +#[stable(feature = "rust1", since = "1.0.0")] +impl<I: Iterator + Sized> Iterator for Box<I> { + fn last(self) -> Option<I::Item> where I: Sized { + (*self).last() + } +} + #[stable(feature = "rust1", since = "1.0.0")] impl<I: DoubleEndedIterator + ?Sized> DoubleEndedIterator for Box<I> { fn next_back(&mut self) -> Option<I::Item> { (**self).next_back() } + fn nth_back(&mut self, n: usize) -> Option<I::Item> { + (**self).nth_back(n) + } } #[stable(feature = "rust1", since = "1.0.0")] impl<I: ExactSizeIterator + ?Sized> ExactSizeIterator for Box<I> { @@ -691,82 +779,26 @@ impl<I: ExactSizeIterator + ?Sized> ExactSizeIterator for Box<I> { #[stable(feature = "fused", since = "1.26.0")] impl<I: FusedIterator + ?Sized> FusedIterator for Box<I> {} +#[stable(feature = "boxed_closure_impls", since = "1.35.0")] +impl<A, F: FnOnce<A> + ?Sized> FnOnce<A> for Box<F> { + type Output = <F as FnOnce<A>>::Output; -/// `FnBox` is a version of the `FnOnce` intended for use with boxed -/// closure objects. The idea is that where one would normally store a -/// `Box<dyn FnOnce()>` in a data structure, you should use -/// `Box<dyn FnBox()>`. The two traits behave essentially the same, except -/// that a `FnBox` closure can only be called if it is boxed. (Note -/// that `FnBox` may be deprecated in the future if `Box<dyn FnOnce()>` -/// closures become directly usable.) -/// -/// # Examples -/// -/// Here is a snippet of code which creates a hashmap full of boxed -/// once closures and then removes them one by one, calling each -/// closure as it is removed. Note that the type of the closures -/// stored in the map is `Box<dyn FnBox() -> i32>` and not `Box<dyn FnOnce() -/// -> i32>`. -/// -/// ``` -/// #![feature(fnbox)] -/// -/// use std::boxed::FnBox; -/// use std::collections::HashMap; -/// -/// fn make_map() -> HashMap<i32, Box<dyn FnBox() -> i32>> { -/// let mut map: HashMap<i32, Box<dyn FnBox() -> i32>> = HashMap::new(); -/// map.insert(1, Box::new(|| 22)); -/// map.insert(2, Box::new(|| 44)); -/// map -/// } -/// -/// fn main() { -/// let mut map = make_map(); -/// for i in &[1, 2] { -/// let f = map.remove(&i).unwrap(); -/// assert_eq!(f(), i * 22); -/// } -/// } -/// ``` -#[rustc_paren_sugar] -#[unstable(feature = "fnbox", - reason = "will be deprecated if and when `Box<FnOnce>` becomes usable", issue = "28796")] -pub trait FnBox<A> { - type Output; - - fn call_box(self: Box<Self>, args: A) -> Self::Output; -} - -#[unstable(feature = "fnbox", - reason = "will be deprecated if and when `Box<FnOnce>` becomes usable", issue = "28796")] -impl<A, F> FnBox<A> for F - where F: FnOnce<A> -{ - type Output = F::Output; - - fn call_box(self: Box<F>, args: A) -> F::Output { - self.call_once(args) + extern "rust-call" fn call_once(self, args: A) -> Self::Output { + <F as FnOnce<A>>::call_once(*self, args) } } -#[unstable(feature = "fnbox", - reason = "will be deprecated if and when `Box<FnOnce>` becomes usable", issue = "28796")] -impl<A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + '_> { - type Output = R; - - extern "rust-call" fn call_once(self, args: A) -> R { - self.call_box(args) +#[stable(feature = "boxed_closure_impls", since = "1.35.0")] +impl<A, F: FnMut<A> + ?Sized> FnMut<A> for Box<F> { + extern "rust-call" fn call_mut(&mut self, args: A) -> Self::Output { + <F as FnMut<A>>::call_mut(self, args) } } -#[unstable(feature = "fnbox", - reason = "will be deprecated if and when `Box<FnOnce>` becomes usable", issue = "28796")] -impl<A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + Send + '_> { - type Output = R; - - extern "rust-call" fn call_once(self, args: A) -> R { - self.call_box(args) +#[stable(feature = "boxed_closure_impls", since = "1.35.0")] +impl<A, F: Fn<A> + ?Sized> Fn<A> for Box<F> { + extern "rust-call" fn call(&self, args: A) -> Self::Output { + <F as Fn<A>>::call(self, args) } } @@ -907,11 +939,11 @@ impl<G: ?Sized + Generator> Generator for Pin<Box<G>> { } } -#[unstable(feature = "futures_api", issue = "50547")] +#[stable(feature = "futures_api", since = "1.36.0")] impl<F: ?Sized + Future + Unpin> Future for Box<F> { type Output = F::Output; - fn poll(mut self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output> { - F::poll(Pin::new(&mut *self), waker) + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + F::poll(Pin::new(&mut *self), cx) } } diff --git a/src/liballoc/collections/binary_heap.rs b/src/liballoc/collections/binary_heap.rs index a171f128c24..9f531f5b83c 100644 --- a/src/liballoc/collections/binary_heap.rs +++ b/src/liballoc/collections/binary_heap.rs @@ -207,6 +207,44 @@ use super::SpecExtend; /// // The heap should now be empty. /// assert!(heap.is_empty()) /// ``` +/// +/// ## Min-heap +/// +/// Either `std::cmp::Reverse` or a custom `Ord` implementation can be used to +/// make `BinaryHeap` a min-heap. This makes `heap.pop()` return the smallest +/// value instead of the greatest one. +/// +/// ``` +/// use std::collections::BinaryHeap; +/// use std::cmp::Reverse; +/// +/// let mut heap = BinaryHeap::new(); +/// +/// // Wrap values in `Reverse` +/// heap.push(Reverse(1)); +/// heap.push(Reverse(5)); +/// heap.push(Reverse(2)); +/// +/// // If we pop these scores now, they should come back in the reverse order. +/// assert_eq!(heap.pop(), Some(Reverse(1))); +/// assert_eq!(heap.pop(), Some(Reverse(2))); +/// assert_eq!(heap.pop(), Some(Reverse(5))); +/// assert_eq!(heap.pop(), None); +/// ``` +/// +/// # Time complexity +/// +/// | [push] | [pop] | [peek]/[peek\_mut] | +/// |--------|----------|--------------------| +/// | O(1)~ | O(log n) | O(1) | +/// +/// The value for `push` is an expected cost; the method documentation gives a +/// more detailed analysis. +/// +/// [push]: #method.push +/// [pop]: #method.pop +/// [peek]: #method.peek +/// [peek\_mut]: #method.peek_mut #[stable(feature = "rust1", since = "1.0.0")] pub struct BinaryHeap<T> { data: Vec<T>, @@ -360,6 +398,10 @@ impl<T: Ord> BinaryHeap<T> { /// } /// assert_eq!(heap.peek(), Some(&2)); /// ``` + /// + /// # Time complexity + /// + /// Cost is O(1) in the worst case. #[stable(feature = "binary_heap_peek_mut", since = "1.12.0")] pub fn peek_mut(&mut self) -> Option<PeekMut<'_, T>> { if self.is_empty() { @@ -387,6 +429,11 @@ impl<T: Ord> BinaryHeap<T> { /// assert_eq!(heap.pop(), Some(1)); /// assert_eq!(heap.pop(), None); /// ``` + /// + /// # Time complexity + /// + /// The worst case cost of `pop` on a heap containing *n* elements is O(log + /// n). #[stable(feature = "rust1", since = "1.0.0")] pub fn pop(&mut self) -> Option<T> { self.data.pop().map(|mut item| { @@ -414,6 +461,22 @@ impl<T: Ord> BinaryHeap<T> { /// assert_eq!(heap.len(), 3); /// assert_eq!(heap.peek(), Some(&5)); /// ``` + /// + /// # Time complexity + /// + /// The expected cost of `push`, averaged over every possible ordering of + /// the elements being pushed, and over a sufficiently large number of + /// pushes, is O(1). This is the most meaningful cost metric when pushing + /// elements that are *not* already in any sorted pattern. + /// + /// The time complexity degrades if elements are pushed in predominantly + /// ascending order. In the worst case, elements are pushed in ascending + /// sorted order and the amortized cost per push is O(log n) against a heap + /// containing *n* elements. + /// + /// The worst case cost of a *single* call to `push` is O(n). The worst case + /// occurs when capacity is exhausted and needs a resize. The resize cost + /// has been amortized in the previous figures. #[stable(feature = "rust1", since = "1.0.0")] pub fn push(&mut self, item: T) { let old_len = self.len(); @@ -626,6 +689,10 @@ impl<T> BinaryHeap<T> { /// assert_eq!(heap.peek(), Some(&5)); /// /// ``` + /// + /// # Time complexity + /// + /// Cost is O(1) in the worst case. #[stable(feature = "rust1", since = "1.0.0")] pub fn peek(&self) -> Option<&T> { self.data.get(0) @@ -968,6 +1035,11 @@ impl<'a, T> Iterator for Iter<'a, T> { fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() } + + #[inline] + fn last(self) -> Option<&'a T> { + self.iter.last() + } } #[stable(feature = "rust1", since = "1.0.0")] @@ -1177,9 +1249,7 @@ impl<T: Ord> BinaryHeap<T> { self.reserve(lower); - for elem in iterator { - self.push(elem); - } + iterator.for_each(move |elem| self.push(elem)); } } diff --git a/src/liballoc/collections/btree/map.rs b/src/liballoc/collections/btree/map.rs index ce29978856f..1683b810556 100644 --- a/src/liballoc/collections/btree/map.rs +++ b/src/liballoc/collections/btree/map.rs @@ -75,10 +75,10 @@ use Entry::*; /// /// // look up the values associated with some keys. /// let to_find = ["Up!", "Office Space"]; -/// for book in &to_find { -/// match movie_reviews.get(book) { -/// Some(review) => println!("{}: {}", book, review), -/// None => println!("{} is unreviewed.", book) +/// for movie in &to_find { +/// match movie_reviews.get(movie) { +/// Some(review) => println!("{}: {}", movie, review), +/// None => println!("{} is unreviewed.", movie) /// } /// } /// @@ -200,7 +200,7 @@ impl<K: Clone, V: Clone> Clone for BTreeMap<K, V> { } } - if self.len() == 0 { + if self.is_empty() { // Ideally we'd call `BTreeMap::new` here, but that has the `K: // Ord` constraint, which this method lacks. BTreeMap { @@ -759,19 +759,19 @@ impl<K: Ord, V> BTreeMap<K, V> { #[stable(feature = "btree_append", since = "1.11.0")] pub fn append(&mut self, other: &mut Self) { // Do we have to append anything at all? - if other.len() == 0 { + if other.is_empty() { return; } // We can just swap `self` and `other` if `self` is empty. - if self.len() == 0 { + if self.is_empty() { mem::swap(self, other); return; } // First, we merge `self` and `other` into a sorted sequence in linear time. - let self_iter = mem::replace(self, BTreeMap::new()).into_iter(); - let other_iter = mem::replace(other, BTreeMap::new()).into_iter(); + let self_iter = mem::take(self).into_iter(); + let other_iter = mem::take(other).into_iter(); let iter = MergeIter { left: self_iter.peekable(), right: other_iter.peekable(), @@ -1193,6 +1193,10 @@ impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> { fn size_hint(&self) -> (usize, Option<usize>) { (self.length, Some(self.length)) } + + fn last(mut self) -> Option<(&'a K, &'a V)> { + self.next_back() + } } #[stable(feature = "fused", since = "1.26.0")] @@ -1253,6 +1257,10 @@ impl<'a, K: 'a, V: 'a> Iterator for IterMut<'a, K, V> { fn size_hint(&self) -> (usize, Option<usize>) { (self.length, Some(self.length)) } + + fn last(mut self) -> Option<(&'a K, &'a mut V)> { + self.next_back() + } } #[stable(feature = "rust1", since = "1.0.0")] @@ -1421,6 +1429,10 @@ impl<'a, K, V> Iterator for Keys<'a, K, V> { fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() } + + fn last(mut self) -> Option<&'a K> { + self.next_back() + } } #[stable(feature = "rust1", since = "1.0.0")] @@ -1458,6 +1470,10 @@ impl<'a, K, V> Iterator for Values<'a, K, V> { fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() } + + fn last(mut self) -> Option<&'a V> { + self.next_back() + } } #[stable(feature = "rust1", since = "1.0.0")] @@ -1495,6 +1511,10 @@ impl<'a, K, V> Iterator for Range<'a, K, V> { unsafe { Some(self.next_unchecked()) } } } + + fn last(mut self) -> Option<(&'a K, &'a V)> { + self.next_back() + } } #[stable(feature = "map_values_mut", since = "1.10.0")] @@ -1508,6 +1528,10 @@ impl<'a, K, V> Iterator for ValuesMut<'a, K, V> { fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() } + + fn last(mut self) -> Option<&'a mut V> { + self.next_back() + } } #[stable(feature = "map_values_mut", since = "1.10.0")] @@ -1626,6 +1650,10 @@ impl<'a, K, V> Iterator for RangeMut<'a, K, V> { unsafe { Some(self.next_unchecked()) } } } + + fn last(mut self) -> Option<(&'a K, &'a mut V)> { + self.next_back() + } } impl<'a, K, V> RangeMut<'a, K, V> { @@ -1727,9 +1755,9 @@ impl<K: Ord, V> FromIterator<(K, V)> for BTreeMap<K, V> { impl<K: Ord, V> Extend<(K, V)> for BTreeMap<K, V> { #[inline] fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iter: T) { - for (k, v) in iter { + iter.into_iter().for_each(move |(k, v)| { self.insert(k, v); - } + }); } } @@ -2004,7 +2032,7 @@ impl<K, V> BTreeMap<K, V> { /// assert_eq!(keys, [1, 2]); /// ``` #[stable(feature = "rust1", since = "1.0.0")] - pub fn keys<'a>(&'a self) -> Keys<'a, K, V> { + pub fn keys(&self) -> Keys<'_, K, V> { Keys { inner: self.iter() } } @@ -2025,7 +2053,7 @@ impl<K, V> BTreeMap<K, V> { /// assert_eq!(values, ["hello", "goodbye"]); /// ``` #[stable(feature = "rust1", since = "1.0.0")] - pub fn values<'a>(&'a self) -> Values<'a, K, V> { + pub fn values(&self) -> Values<'_, K, V> { Values { inner: self.iter() } } @@ -2529,8 +2557,8 @@ enum UnderflowResult<'a, K, V> { Stole(NodeRef<marker::Mut<'a>, K, V, marker::Internal>), } -fn handle_underfull_node<'a, K, V>(node: NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>) - -> UnderflowResult<'a, K, V> { +fn handle_underfull_node<K, V>(node: NodeRef<marker::Mut<'_>, K, V, marker::LeafOrInternal>) + -> UnderflowResult<'_, K, V> { let parent = if let Ok(parent) = node.ascend() { parent } else { diff --git a/src/liballoc/collections/btree/node.rs b/src/liballoc/collections/btree/node.rs index 66d619b1298..e067096f0c7 100644 --- a/src/liballoc/collections/btree/node.rs +++ b/src/liballoc/collections/btree/node.rs @@ -106,10 +106,10 @@ impl<K, V> LeafNode<K, V> { LeafNode { // As a general policy, we leave fields uninitialized if they can be, as this should // be both slightly faster and easier to track in Valgrind. - keys: uninitialized_array![_; CAPACITY], - vals: uninitialized_array![_; CAPACITY], + keys: uninit_array![_; CAPACITY], + vals: uninit_array![_; CAPACITY], parent: ptr::null(), - parent_idx: MaybeUninit::uninitialized(), + parent_idx: MaybeUninit::uninit(), len: 0 } } @@ -129,7 +129,7 @@ unsafe impl Sync for NodeHeader<(), ()> {} // ever take a pointer past the first key. static EMPTY_ROOT_NODE: NodeHeader<(), ()> = NodeHeader { parent: ptr::null(), - parent_idx: MaybeUninit::uninitialized(), + parent_idx: MaybeUninit::uninit(), len: 0, keys_start: [], }; @@ -159,7 +159,7 @@ impl<K, V> InternalNode<K, V> { unsafe fn new() -> Self { InternalNode { data: LeafNode::new(), - edges: uninitialized_array![_; 2*B], + edges: uninit_array![_; 2*B], } } } @@ -261,7 +261,7 @@ impl<K, V> Root<K, V> { -> NodeRef<marker::Mut<'_>, K, V, marker::Internal> { debug_assert!(!self.is_shared_root()); let mut new_node = Box::new(unsafe { InternalNode::new() }); - new_node.edges[0].set(unsafe { BoxedNode::from_ptr(self.node.as_ptr()) }); + new_node.edges[0].write(unsafe { BoxedNode::from_ptr(self.node.as_ptr()) }); self.node = BoxedNode::from_internal(new_node); self.height += 1; @@ -394,7 +394,7 @@ impl<BorrowType, K, V, Type> NodeRef<BorrowType, K, V, Type> { } /// Temporarily takes out another, immutable reference to the same node. - fn reborrow<'a>(&'a self) -> NodeRef<marker::Immut<'a>, K, V, Type> { + fn reborrow(&self) -> NodeRef<marker::Immut<'_>, K, V, Type> { NodeRef { height: self.height, node: self.node, @@ -737,7 +737,7 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Internal> { unsafe { ptr::write(self.keys_mut().get_unchecked_mut(idx), key); ptr::write(self.vals_mut().get_unchecked_mut(idx), val); - self.as_internal_mut().edges.get_unchecked_mut(idx + 1).set(edge.node); + self.as_internal_mut().edges.get_unchecked_mut(idx + 1).write(edge.node); (*self.as_leaf_mut()).len += 1; @@ -1080,7 +1080,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker:: let mut child = self.descend(); unsafe { (*child.as_leaf_mut()).parent = ptr; - (*child.as_leaf_mut()).parent_idx.set(idx); + (*child.as_leaf_mut()).parent_idx.write(idx); } } diff --git a/src/liballoc/collections/btree/set.rs b/src/liballoc/collections/btree/set.rs index 2be6455ad59..d3af910a82c 100644 --- a/src/liballoc/collections/btree/set.rs +++ b/src/liballoc/collections/btree/set.rs @@ -3,7 +3,7 @@ use core::borrow::Borrow; use core::cmp::Ordering::{self, Less, Greater, Equal}; -use core::cmp::{min, max}; +use core::cmp::max; use core::fmt::{self, Debug}; use core::iter::{Peekable, FromIterator, FusedIterator}; use core::ops::{BitOr, BitAnd, BitXor, Sub, RangeBounds}; @@ -118,17 +118,36 @@ pub struct Range<'a, T: 'a> { /// [`difference`]: struct.BTreeSet.html#method.difference #[stable(feature = "rust1", since = "1.0.0")] pub struct Difference<'a, T: 'a> { - a: Peekable<Iter<'a, T>>, - b: Peekable<Iter<'a, T>>, + inner: DifferenceInner<'a, T>, +} +enum DifferenceInner<'a, T: 'a> { + Stitch { + self_iter: Iter<'a, T>, + other_iter: Peekable<Iter<'a, T>>, + }, + Search { + self_iter: Iter<'a, T>, + other_set: &'a BTreeSet<T>, + }, } #[stable(feature = "collection_debug", since = "1.17.0")] impl<T: fmt::Debug> fmt::Debug for Difference<'_, T> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("Difference") - .field(&self.a) - .field(&self.b) - .finish() + match &self.inner { + DifferenceInner::Stitch { + self_iter, + other_iter, + } => f + .debug_tuple("Difference") + .field(&self_iter) + .field(&other_iter) + .finish(), + DifferenceInner::Search { + self_iter, + other_set: _, + } => f.debug_tuple("Difference").field(&self_iter).finish(), + } } } @@ -164,17 +183,36 @@ impl<T: fmt::Debug> fmt::Debug for SymmetricDifference<'_, T> { /// [`intersection`]: struct.BTreeSet.html#method.intersection #[stable(feature = "rust1", since = "1.0.0")] pub struct Intersection<'a, T: 'a> { - a: Peekable<Iter<'a, T>>, - b: Peekable<Iter<'a, T>>, + inner: IntersectionInner<'a, T>, +} +enum IntersectionInner<'a, T: 'a> { + Stitch { + small_iter: Iter<'a, T>, // for size_hint, should be the smaller of the sets + other_iter: Iter<'a, T>, + }, + Search { + small_iter: Iter<'a, T>, + large_set: &'a BTreeSet<T>, + }, } #[stable(feature = "collection_debug", since = "1.17.0")] impl<T: fmt::Debug> fmt::Debug for Intersection<'_, T> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("Intersection") - .field(&self.a) - .field(&self.b) - .finish() + match &self.inner { + IntersectionInner::Stitch { + small_iter, + other_iter, + } => f + .debug_tuple("Intersection") + .field(&small_iter) + .field(&other_iter) + .finish(), + IntersectionInner::Search { + small_iter, + large_set: _, + } => f.debug_tuple("Intersection").field(&small_iter).finish(), + } } } @@ -201,6 +239,14 @@ impl<T: fmt::Debug> fmt::Debug for Union<'_, T> { } } +// This constant is used by functions that compare two sets. +// It estimates the relative size at which searching performs better +// than iterating, based on the benchmarks in +// https://github.com/ssomers/rust_bench_btreeset_intersection; +// It's used to divide rather than multiply sizes, to rule out overflow, +// and it's a power of two to make that division cheap. +const ITER_PERFORMANCE_TIPPING_SIZE_DIFF: usize = 16; + impl<T: Ord> BTreeSet<T> { /// Makes a new `BTreeSet` with a reasonable choice of B. /// @@ -268,9 +314,24 @@ impl<T: Ord> BTreeSet<T> { /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn difference<'a>(&'a self, other: &'a BTreeSet<T>) -> Difference<'a, T> { - Difference { - a: self.iter().peekable(), - b: other.iter().peekable(), + if self.len() > other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF { + // Self is bigger than or not much smaller than other set. + // Iterate both sets jointly, spotting matches along the way. + Difference { + inner: DifferenceInner::Stitch { + self_iter: self.iter(), + other_iter: other.iter().peekable(), + }, + } + } else { + // Self is much smaller than other set, or both sets are empty. + // Iterate the small set, searching for matches in the large set. + Difference { + inner: DifferenceInner::Search { + self_iter: self.iter(), + other_set: other, + }, + } } } @@ -326,9 +387,29 @@ impl<T: Ord> BTreeSet<T> { /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn intersection<'a>(&'a self, other: &'a BTreeSet<T>) -> Intersection<'a, T> { - Intersection { - a: self.iter().peekable(), - b: other.iter().peekable(), + let (small, other) = if self.len() <= other.len() { + (self, other) + } else { + (other, self) + }; + if small.len() > other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF { + // Small set is not much smaller than other set. + // Iterate both sets jointly, spotting matches along the way. + Intersection { + inner: IntersectionInner::Stitch { + small_iter: small.iter(), + other_iter: other.iter(), + }, + } + } else { + // Big difference in number of elements, or both sets are empty. + // Iterate the small set, searching for matches in the large set. + Intersection { + inner: IntersectionInner::Search { + small_iter: small.iter(), + large_set: other, + }, + } } } @@ -462,28 +543,44 @@ impl<T: Ord> BTreeSet<T> { /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn is_subset(&self, other: &BTreeSet<T>) -> bool { - // Stolen from TreeMap - let mut x = self.iter(); - let mut y = other.iter(); - let mut a = x.next(); - let mut b = y.next(); - while a.is_some() { - if b.is_none() { - return false; - } + // Same result as self.difference(other).next().is_none() + // but the 3 paths below are faster (in order: hugely, 20%, 5%). + if self.len() > other.len() { + false + } else if self.len() > other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF { + // Self is not much smaller than other set. + // Stolen from TreeMap + let mut x = self.iter(); + let mut y = other.iter(); + let mut a = x.next(); + let mut b = y.next(); + while a.is_some() { + if b.is_none() { + return false; + } - let a1 = a.unwrap(); - let b1 = b.unwrap(); + let a1 = a.unwrap(); + let b1 = b.unwrap(); - match b1.cmp(a1) { - Less => (), - Greater => return false, - Equal => a = x.next(), - } + match b1.cmp(a1) { + Less => (), + Greater => return false, + Equal => a = x.next(), + } - b = y.next(); + b = y.next(); + } + true + } else { + // Big difference in number of elements, or both sets are empty. + // Iterate the small set, searching for matches in the large set. + for next in self { + if !other.contains(next) { + return false; + } + } + true } - true } /// Returns `true` if the set is a superset of another, @@ -786,9 +883,9 @@ impl<'a, T> IntoIterator for &'a BTreeSet<T> { impl<T: Ord> Extend<T> for BTreeSet<T> { #[inline] fn extend<Iter: IntoIterator<Item = T>>(&mut self, iter: Iter) { - for elem in iter { + iter.into_iter().for_each(move |elem| { self.insert(elem); - } + }); } } @@ -922,6 +1019,9 @@ impl<'a, T> Iterator for Iter<'a, T> { fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() } + fn last(mut self) -> Option<&'a T> { + self.next_back() + } } #[stable(feature = "rust1", since = "1.0.0")] impl<'a, T> DoubleEndedIterator for Iter<'a, T> { @@ -976,6 +1076,10 @@ impl<'a, T> Iterator for Range<'a, T> { fn next(&mut self) -> Option<&'a T> { self.iter.next().map(|(k, _)| k) } + + fn last(mut self) -> Option<&'a T> { + self.next_back() + } } #[stable(feature = "btree_range", since = "1.17.0")] @@ -1001,8 +1105,22 @@ fn cmp_opt<T: Ord>(x: Option<&T>, y: Option<&T>, short: Ordering, long: Ordering impl<T> Clone for Difference<'_, T> { fn clone(&self) -> Self { Difference { - a: self.a.clone(), - b: self.b.clone(), + inner: match &self.inner { + DifferenceInner::Stitch { + self_iter, + other_iter, + } => DifferenceInner::Stitch { + self_iter: self_iter.clone(), + other_iter: other_iter.clone(), + }, + DifferenceInner::Search { + self_iter, + other_set, + } => DifferenceInner::Search { + self_iter: self_iter.clone(), + other_set, + }, + }, } } } @@ -1011,24 +1129,52 @@ impl<'a, T: Ord> Iterator for Difference<'a, T> { type Item = &'a T; fn next(&mut self) -> Option<&'a T> { - loop { - match cmp_opt(self.a.peek(), self.b.peek(), Less, Less) { - Less => return self.a.next(), - Equal => { - self.a.next(); - self.b.next(); - } - Greater => { - self.b.next(); + match &mut self.inner { + DifferenceInner::Stitch { + self_iter, + other_iter, + } => { + let mut self_next = self_iter.next()?; + loop { + match other_iter + .peek() + .map_or(Less, |other_next| Ord::cmp(self_next, other_next)) + { + Less => return Some(self_next), + Equal => { + self_next = self_iter.next()?; + other_iter.next(); + } + Greater => { + other_iter.next(); + } + } } } + DifferenceInner::Search { + self_iter, + other_set, + } => loop { + let self_next = self_iter.next()?; + if !other_set.contains(&self_next) { + return Some(self_next); + } + }, } } fn size_hint(&self) -> (usize, Option<usize>) { - let a_len = self.a.len(); - let b_len = self.b.len(); - (a_len.saturating_sub(b_len), Some(a_len)) + let (self_len, other_len) = match &self.inner { + DifferenceInner::Stitch { + self_iter, + other_iter + } => (self_iter.len(), other_iter.len()), + DifferenceInner::Search { + self_iter, + other_set + } => (self_iter.len(), other_set.len()), + }; + (self_len.saturating_sub(other_len), Some(self_len)) } } @@ -1073,8 +1219,22 @@ impl<T: Ord> FusedIterator for SymmetricDifference<'_, T> {} impl<T> Clone for Intersection<'_, T> { fn clone(&self) -> Self { Intersection { - a: self.a.clone(), - b: self.b.clone(), + inner: match &self.inner { + IntersectionInner::Stitch { + small_iter, + other_iter, + } => IntersectionInner::Stitch { + small_iter: small_iter.clone(), + other_iter: other_iter.clone(), + }, + IntersectionInner::Search { + small_iter, + large_set, + } => IntersectionInner::Search { + small_iter: small_iter.clone(), + large_set, + }, + }, } } } @@ -1083,24 +1243,39 @@ impl<'a, T: Ord> Iterator for Intersection<'a, T> { type Item = &'a T; fn next(&mut self) -> Option<&'a T> { - loop { - match Ord::cmp(self.a.peek()?, self.b.peek()?) { - Less => { - self.a.next(); - } - Equal => { - self.b.next(); - return self.a.next(); - } - Greater => { - self.b.next(); + match &mut self.inner { + IntersectionInner::Stitch { + small_iter, + other_iter, + } => { + let mut small_next = small_iter.next()?; + let mut other_next = other_iter.next()?; + loop { + match Ord::cmp(small_next, other_next) { + Less => small_next = small_iter.next()?, + Greater => other_next = other_iter.next()?, + Equal => return Some(small_next), + } } } + IntersectionInner::Search { + small_iter, + large_set, + } => loop { + let small_next = small_iter.next()?; + if large_set.contains(&small_next) { + return Some(small_next); + } + }, } } fn size_hint(&self) -> (usize, Option<usize>) { - (0, Some(min(self.a.len(), self.b.len()))) + let min_len = match &self.inner { + IntersectionInner::Stitch { small_iter, .. } => small_iter.len(), + IntersectionInner::Search { small_iter, .. } => small_iter.len(), + }; + (0, Some(min_len)) } } diff --git a/src/liballoc/collections/linked_list.rs b/src/liballoc/collections/linked_list.rs index c2ee2e63156..a14a3fe9994 100644 --- a/src/liballoc/collections/linked_list.rs +++ b/src/liballoc/collections/linked_list.rs @@ -23,6 +23,9 @@ use core::ptr::NonNull; use crate::boxed::Box; use super::SpecExtend; +#[cfg(test)] +mod tests; + /// A doubly-linked list with owned nodes. /// /// The `LinkedList` allows pushing and popping elements at either end @@ -86,6 +89,9 @@ impl<T> Clone for Iter<'_, T> { /// [`LinkedList`]: struct.LinkedList.html #[stable(feature = "rust1", since = "1.0.0")] pub struct IterMut<'a, T: 'a> { + // We do *not* exclusively own the entire list here, references to node's `element` + // have been handed out by the iterator! So be careful when using this; the methods + // called must be aware that there can be aliasing pointers to `element`. list: &'a mut LinkedList<T>, head: Option<NonNull<Node<T>>>, tail: Option<NonNull<Node<T>>>, @@ -143,6 +149,8 @@ impl<T> LinkedList<T> { /// Adds the given node to the front of the list. #[inline] fn push_front_node(&mut self, mut node: Box<Node<T>>) { + // This method takes care not to create mutable references to whole nodes, + // to maintain validity of aliasing pointers into `element`. unsafe { node.next = self.head; node.prev = None; @@ -150,7 +158,8 @@ impl<T> LinkedList<T> { match self.head { None => self.tail = node, - Some(mut head) => head.as_mut().prev = node, + // Not creating new mutable (unique!) references overlapping `element`. + Some(head) => (*head.as_ptr()).prev = node, } self.head = node; @@ -161,13 +170,16 @@ impl<T> LinkedList<T> { /// Removes and returns the node at the front of the list. #[inline] fn pop_front_node(&mut self) -> Option<Box<Node<T>>> { + // This method takes care not to create mutable references to whole nodes, + // to maintain validity of aliasing pointers into `element`. self.head.map(|node| unsafe { let node = Box::from_raw(node.as_ptr()); self.head = node.next; match self.head { None => self.tail = None, - Some(mut head) => head.as_mut().prev = None, + // Not creating new mutable (unique!) references overlapping `element`. + Some(head) => (*head.as_ptr()).prev = None, } self.len -= 1; @@ -178,6 +190,8 @@ impl<T> LinkedList<T> { /// Adds the given node to the back of the list. #[inline] fn push_back_node(&mut self, mut node: Box<Node<T>>) { + // This method takes care not to create mutable references to whole nodes, + // to maintain validity of aliasing pointers into `element`. unsafe { node.next = None; node.prev = self.tail; @@ -185,7 +199,8 @@ impl<T> LinkedList<T> { match self.tail { None => self.head = node, - Some(mut tail) => tail.as_mut().next = node, + // Not creating new mutable (unique!) references overlapping `element`. + Some(tail) => (*tail.as_ptr()).next = node, } self.tail = node; @@ -196,13 +211,16 @@ impl<T> LinkedList<T> { /// Removes and returns the node at the back of the list. #[inline] fn pop_back_node(&mut self) -> Option<Box<Node<T>>> { + // This method takes care not to create mutable references to whole nodes, + // to maintain validity of aliasing pointers into `element`. self.tail.map(|node| unsafe { let node = Box::from_raw(node.as_ptr()); self.tail = node.prev; match self.tail { None => self.head = None, - Some(mut tail) => tail.as_mut().next = None, + // Not creating new mutable (unique!) references overlapping `element`. + Some(tail) => (*tail.as_ptr()).next = None, } self.len -= 1; @@ -213,20 +231,24 @@ impl<T> LinkedList<T> { /// Unlinks the specified node from the current list. /// /// Warning: this will not check that the provided node belongs to the current list. + /// + /// This method takes care not to create mutable references to `element`, to + /// maintain validity of aliasing pointers. #[inline] unsafe fn unlink_node(&mut self, mut node: NonNull<Node<T>>) { - let node = node.as_mut(); + let node = node.as_mut(); // this one is ours now, we can create an &mut. + // Not creating new mutable (unique!) references overlapping `element`. match node.prev { - Some(mut prev) => prev.as_mut().next = node.next.clone(), + Some(prev) => (*prev.as_ptr()).next = node.next, // this node is the head node - None => self.head = node.next.clone(), + None => self.head = node.next, }; match node.next { - Some(mut next) => next.as_mut().prev = node.prev.clone(), + Some(next) => (*next.as_ptr()).prev = node.prev, // this node is the tail node - None => self.tail = node.prev.clone(), + None => self.tail = node.prev, }; self.len -= 1; @@ -297,6 +319,8 @@ impl<T> LinkedList<T> { match self.tail { None => mem::swap(self, other), Some(mut tail) => { + // `as_mut` is okay here because we have exclusive access to the entirety + // of both lists. if let Some(mut other_head) = other.head.take() { unsafe { tail.as_mut().next = Some(other_head); @@ -687,7 +711,7 @@ impl<T> LinkedList<T> { let len = self.len(); assert!(at <= len, "Cannot split off at a nonexistent index"); if at == 0 { - return mem::replace(self, Self::new()); + return mem::take(self); } else if at == len { return Self::new(); } @@ -811,6 +835,11 @@ impl<'a, T> Iterator for Iter<'a, T> { fn size_hint(&self) -> (usize, Option<usize>) { (self.len, Some(self.len)) } + + #[inline] + fn last(mut self) -> Option<&'a T> { + self.next_back() + } } #[stable(feature = "rust1", since = "1.0.0")] @@ -860,6 +889,11 @@ impl<'a, T> Iterator for IterMut<'a, T> { fn size_hint(&self) -> (usize, Option<usize>) { (self.len, Some(self.len)) } + + #[inline] + fn last(mut self) -> Option<&'a mut T> { + self.next_back() + } } #[stable(feature = "rust1", since = "1.0.0")] @@ -916,9 +950,11 @@ impl<T> IterMut<'_, T> { issue = "27794")] pub fn insert_next(&mut self, element: T) { match self.head { + // `push_back` is okay with aliasing `element` references None => self.list.push_back(element), - Some(mut head) => unsafe { - let mut prev = match head.as_ref().prev { + Some(head) => unsafe { + let prev = match head.as_ref().prev { + // `push_front` is okay with aliasing nodes None => return self.list.push_front(element), Some(prev) => prev, }; @@ -929,8 +965,10 @@ impl<T> IterMut<'_, T> { element, })); - prev.as_mut().next = node; - head.as_mut().prev = node; + // Not creating references to entire nodes to not invalidate the + // reference to `element` we handed to the user. + (*prev.as_ptr()).next = node; + (*head.as_ptr()).prev = node; self.list.len += 1; }, @@ -994,6 +1032,7 @@ impl<T, F> Iterator for DrainFilter<'_, T, F> self.idx += 1; if (self.pred)(&mut node.as_mut().element) { + // `unlink_node` is okay with aliasing `element` references. self.list.unlink_node(node); return Some(Box::from_raw(node.as_ptr()).element); } @@ -1107,9 +1146,7 @@ impl<T> Extend<T> for LinkedList<T> { impl<I: IntoIterator> SpecExtend<I> for LinkedList<I::Item> { default fn spec_extend(&mut self, iter: I) { - for elt in iter { - self.push_back(elt); - } + iter.into_iter().for_each(move |elt| self.push_back(elt)); } } @@ -1210,271 +1247,3 @@ unsafe impl<T: Send> Send for IterMut<'_, T> {} #[stable(feature = "rust1", since = "1.0.0")] unsafe impl<T: Sync> Sync for IterMut<'_, T> {} - -#[cfg(test)] -mod tests { - use std::thread; - use std::vec::Vec; - - use rand::{thread_rng, RngCore}; - - use super::{LinkedList, Node}; - - #[cfg(test)] - fn list_from<T: Clone>(v: &[T]) -> LinkedList<T> { - v.iter().cloned().collect() - } - - pub fn check_links<T>(list: &LinkedList<T>) { - unsafe { - let mut len = 0; - let mut last_ptr: Option<&Node<T>> = None; - let mut node_ptr: &Node<T>; - match list.head { - None => { - // tail node should also be None. - assert!(list.tail.is_none()); - assert_eq!(0, list.len); - return; - } - Some(node) => node_ptr = &*node.as_ptr(), - } - loop { - match (last_ptr, node_ptr.prev) { - (None, None) => {} - (None, _) => panic!("prev link for head"), - (Some(p), Some(pptr)) => { - assert_eq!(p as *const Node<T>, pptr.as_ptr() as *const Node<T>); - } - _ => panic!("prev link is none, not good"), - } - match node_ptr.next { - Some(next) => { - last_ptr = Some(node_ptr); - node_ptr = &*next.as_ptr(); - len += 1; - } - None => { - len += 1; - break; - } - } - } - - // verify that the tail node points to the last node. - let tail = list.tail.as_ref().expect("some tail node").as_ref(); - assert_eq!(tail as *const Node<T>, node_ptr as *const Node<T>); - // check that len matches interior links. - assert_eq!(len, list.len); - } - } - - #[test] - fn test_append() { - // Empty to empty - { - let mut m = LinkedList::<i32>::new(); - let mut n = LinkedList::new(); - m.append(&mut n); - check_links(&m); - assert_eq!(m.len(), 0); - assert_eq!(n.len(), 0); - } - // Non-empty to empty - { - let mut m = LinkedList::new(); - let mut n = LinkedList::new(); - n.push_back(2); - m.append(&mut n); - check_links(&m); - assert_eq!(m.len(), 1); - assert_eq!(m.pop_back(), Some(2)); - assert_eq!(n.len(), 0); - check_links(&m); - } - // Empty to non-empty - { - let mut m = LinkedList::new(); - let mut n = LinkedList::new(); - m.push_back(2); - m.append(&mut n); - check_links(&m); - assert_eq!(m.len(), 1); - assert_eq!(m.pop_back(), Some(2)); - check_links(&m); - } - - // Non-empty to non-empty - let v = vec![1, 2, 3, 4, 5]; - let u = vec![9, 8, 1, 2, 3, 4, 5]; - let mut m = list_from(&v); - let mut n = list_from(&u); - m.append(&mut n); - check_links(&m); - let mut sum = v; - sum.extend_from_slice(&u); - assert_eq!(sum.len(), m.len()); - for elt in sum { - assert_eq!(m.pop_front(), Some(elt)) - } - assert_eq!(n.len(), 0); - // let's make sure it's working properly, since we - // did some direct changes to private members - n.push_back(3); - assert_eq!(n.len(), 1); - assert_eq!(n.pop_front(), Some(3)); - check_links(&n); - } - - #[test] - fn test_insert_prev() { - let mut m = list_from(&[0, 2, 4, 6, 8]); - let len = m.len(); - { - let mut it = m.iter_mut(); - it.insert_next(-2); - loop { - match it.next() { - None => break, - Some(elt) => { - it.insert_next(*elt + 1); - match it.peek_next() { - Some(x) => assert_eq!(*x, *elt + 2), - None => assert_eq!(8, *elt), - } - } - } - } - it.insert_next(0); - it.insert_next(1); - } - check_links(&m); - assert_eq!(m.len(), 3 + len * 2); - assert_eq!(m.into_iter().collect::<Vec<_>>(), - [-2, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1]); - } - - #[test] - #[cfg_attr(target_os = "emscripten", ignore)] - fn test_send() { - let n = list_from(&[1, 2, 3]); - thread::spawn(move || { - check_links(&n); - let a: &[_] = &[&1, &2, &3]; - assert_eq!(a, &*n.iter().collect::<Vec<_>>()); - }) - .join() - .ok() - .unwrap(); - } - - #[test] - fn test_fuzz() { - for _ in 0..25 { - fuzz_test(3); - fuzz_test(16); - fuzz_test(189); - } - } - - #[test] - fn test_26021() { - // There was a bug in split_off that failed to null out the RHS's head's prev ptr. - // This caused the RHS's dtor to walk up into the LHS at drop and delete all of - // its nodes. - // - // https://github.com/rust-lang/rust/issues/26021 - let mut v1 = LinkedList::new(); - v1.push_front(1); - v1.push_front(1); - v1.push_front(1); - v1.push_front(1); - let _ = v1.split_off(3); // Dropping this now should not cause laundry consumption - assert_eq!(v1.len(), 3); - - assert_eq!(v1.iter().len(), 3); - assert_eq!(v1.iter().collect::<Vec<_>>().len(), 3); - } - - #[test] - fn test_split_off() { - let mut v1 = LinkedList::new(); - v1.push_front(1); - v1.push_front(1); - v1.push_front(1); - v1.push_front(1); - - // test all splits - for ix in 0..1 + v1.len() { - let mut a = v1.clone(); - let b = a.split_off(ix); - check_links(&a); - check_links(&b); - a.extend(b); - assert_eq!(v1, a); - } - } - - #[cfg(test)] - fn fuzz_test(sz: i32) { - let mut m: LinkedList<_> = LinkedList::new(); - let mut v = vec![]; - for i in 0..sz { - check_links(&m); - let r: u8 = thread_rng().next_u32() as u8; - match r % 6 { - 0 => { - m.pop_back(); - v.pop(); - } - 1 => { - if !v.is_empty() { - m.pop_front(); - v.remove(0); - } - } - 2 | 4 => { - m.push_front(-i); - v.insert(0, -i); - } - 3 | 5 | _ => { - m.push_back(i); - v.push(i); - } - } - } - - check_links(&m); - - let mut i = 0; - for (a, &b) in m.into_iter().zip(&v) { - i += 1; - assert_eq!(a, b); - } - assert_eq!(i, v.len()); - } - - #[test] - fn drain_filter_test() { - let mut m: LinkedList<u32> = LinkedList::new(); - m.extend(&[1, 2, 3, 4, 5, 6]); - let deleted = m.drain_filter(|v| *v < 4).collect::<Vec<_>>(); - - check_links(&m); - - assert_eq!(deleted, &[1, 2, 3]); - assert_eq!(m.into_iter().collect::<Vec<_>>(), &[4, 5, 6]); - } - - #[test] - fn drain_to_empty_test() { - let mut m: LinkedList<u32> = LinkedList::new(); - m.extend(&[1, 2, 3, 4, 5, 6]); - let deleted = m.drain_filter(|_| true).collect::<Vec<_>>(); - - check_links(&m); - - assert_eq!(deleted, &[1, 2, 3, 4, 5, 6]); - assert_eq!(m.into_iter().collect::<Vec<_>>(), &[]); - } -} diff --git a/src/liballoc/collections/linked_list/tests.rs b/src/liballoc/collections/linked_list/tests.rs new file mode 100644 index 00000000000..9a6c57d2869 --- /dev/null +++ b/src/liballoc/collections/linked_list/tests.rs @@ -0,0 +1,264 @@ +use super::*; + +use std::thread; +use std::vec::Vec; + +use rand::{thread_rng, RngCore}; + +fn list_from<T: Clone>(v: &[T]) -> LinkedList<T> { + v.iter().cloned().collect() +} + +pub fn check_links<T>(list: &LinkedList<T>) { + unsafe { + let mut len = 0; + let mut last_ptr: Option<&Node<T>> = None; + let mut node_ptr: &Node<T>; + match list.head { + None => { + // tail node should also be None. + assert!(list.tail.is_none()); + assert_eq!(0, list.len); + return; + } + Some(node) => node_ptr = &*node.as_ptr(), + } + loop { + match (last_ptr, node_ptr.prev) { + (None, None) => {} + (None, _) => panic!("prev link for head"), + (Some(p), Some(pptr)) => { + assert_eq!(p as *const Node<T>, pptr.as_ptr() as *const Node<T>); + } + _ => panic!("prev link is none, not good"), + } + match node_ptr.next { + Some(next) => { + last_ptr = Some(node_ptr); + node_ptr = &*next.as_ptr(); + len += 1; + } + None => { + len += 1; + break; + } + } + } + + // verify that the tail node points to the last node. + let tail = list.tail.as_ref().expect("some tail node").as_ref(); + assert_eq!(tail as *const Node<T>, node_ptr as *const Node<T>); + // check that len matches interior links. + assert_eq!(len, list.len); + } +} + +#[test] +fn test_append() { + // Empty to empty + { + let mut m = LinkedList::<i32>::new(); + let mut n = LinkedList::new(); + m.append(&mut n); + check_links(&m); + assert_eq!(m.len(), 0); + assert_eq!(n.len(), 0); + } + // Non-empty to empty + { + let mut m = LinkedList::new(); + let mut n = LinkedList::new(); + n.push_back(2); + m.append(&mut n); + check_links(&m); + assert_eq!(m.len(), 1); + assert_eq!(m.pop_back(), Some(2)); + assert_eq!(n.len(), 0); + check_links(&m); + } + // Empty to non-empty + { + let mut m = LinkedList::new(); + let mut n = LinkedList::new(); + m.push_back(2); + m.append(&mut n); + check_links(&m); + assert_eq!(m.len(), 1); + assert_eq!(m.pop_back(), Some(2)); + check_links(&m); + } + + // Non-empty to non-empty + let v = vec![1, 2, 3, 4, 5]; + let u = vec![9, 8, 1, 2, 3, 4, 5]; + let mut m = list_from(&v); + let mut n = list_from(&u); + m.append(&mut n); + check_links(&m); + let mut sum = v; + sum.extend_from_slice(&u); + assert_eq!(sum.len(), m.len()); + for elt in sum { + assert_eq!(m.pop_front(), Some(elt)) + } + assert_eq!(n.len(), 0); + // let's make sure it's working properly, since we + // did some direct changes to private members + n.push_back(3); + assert_eq!(n.len(), 1); + assert_eq!(n.pop_front(), Some(3)); + check_links(&n); +} + +#[test] +fn test_insert_prev() { + let mut m = list_from(&[0, 2, 4, 6, 8]); + let len = m.len(); + { + let mut it = m.iter_mut(); + it.insert_next(-2); + loop { + match it.next() { + None => break, + Some(elt) => { + it.insert_next(*elt + 1); + match it.peek_next() { + Some(x) => assert_eq!(*x, *elt + 2), + None => assert_eq!(8, *elt), + } + } + } + } + it.insert_next(0); + it.insert_next(1); + } + check_links(&m); + assert_eq!(m.len(), 3 + len * 2); + assert_eq!(m.into_iter().collect::<Vec<_>>(), + [-2, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1]); +} + +#[test] +#[cfg_attr(target_os = "emscripten", ignore)] +#[cfg(not(miri))] // Miri does not support threads +fn test_send() { + let n = list_from(&[1, 2, 3]); + thread::spawn(move || { + check_links(&n); + let a: &[_] = &[&1, &2, &3]; + assert_eq!(a, &*n.iter().collect::<Vec<_>>()); + }) + .join() + .ok() + .unwrap(); +} + +#[test] +fn test_fuzz() { + for _ in 0..25 { + fuzz_test(3); + fuzz_test(16); + #[cfg(not(miri))] // Miri is too slow + fuzz_test(189); + } +} + +#[test] +fn test_26021() { + // There was a bug in split_off that failed to null out the RHS's head's prev ptr. + // This caused the RHS's dtor to walk up into the LHS at drop and delete all of + // its nodes. + // + // https://github.com/rust-lang/rust/issues/26021 + let mut v1 = LinkedList::new(); + v1.push_front(1); + v1.push_front(1); + v1.push_front(1); + v1.push_front(1); + let _ = v1.split_off(3); // Dropping this now should not cause laundry consumption + assert_eq!(v1.len(), 3); + + assert_eq!(v1.iter().len(), 3); + assert_eq!(v1.iter().collect::<Vec<_>>().len(), 3); +} + +#[test] +fn test_split_off() { + let mut v1 = LinkedList::new(); + v1.push_front(1); + v1.push_front(1); + v1.push_front(1); + v1.push_front(1); + + // test all splits + for ix in 0..1 + v1.len() { + let mut a = v1.clone(); + let b = a.split_off(ix); + check_links(&a); + check_links(&b); + a.extend(b); + assert_eq!(v1, a); + } +} + +fn fuzz_test(sz: i32) { + let mut m: LinkedList<_> = LinkedList::new(); + let mut v = vec![]; + for i in 0..sz { + check_links(&m); + let r: u8 = thread_rng().next_u32() as u8; + match r % 6 { + 0 => { + m.pop_back(); + v.pop(); + } + 1 => { + if !v.is_empty() { + m.pop_front(); + v.remove(0); + } + } + 2 | 4 => { + m.push_front(-i); + v.insert(0, -i); + } + 3 | 5 | _ => { + m.push_back(i); + v.push(i); + } + } + } + + check_links(&m); + + let mut i = 0; + for (a, &b) in m.into_iter().zip(&v) { + i += 1; + assert_eq!(a, b); + } + assert_eq!(i, v.len()); +} + +#[test] +fn drain_filter_test() { + let mut m: LinkedList<u32> = LinkedList::new(); + m.extend(&[1, 2, 3, 4, 5, 6]); + let deleted = m.drain_filter(|v| *v < 4).collect::<Vec<_>>(); + + check_links(&m); + + assert_eq!(deleted, &[1, 2, 3]); + assert_eq!(m.into_iter().collect::<Vec<_>>(), &[4, 5, 6]); +} + +#[test] +fn drain_to_empty_test() { + let mut m: LinkedList<u32> = LinkedList::new(); + m.extend(&[1, 2, 3, 4, 5, 6]); + let deleted = m.drain_filter(|_| true).collect::<Vec<_>>(); + + check_links(&m); + + assert_eq!(deleted, &[1, 2, 3, 4, 5, 6]); + assert_eq!(m.into_iter().collect::<Vec<_>>(), &[]); +} diff --git a/src/liballoc/collections/vec_deque.rs b/src/liballoc/collections/vec_deque.rs index 4e90f783ec6..9240346ace9 100644 --- a/src/liballoc/collections/vec_deque.rs +++ b/src/liballoc/collections/vec_deque.rs @@ -7,6 +7,7 @@ #![stable(feature = "rust1", since = "1.0.0")] +use core::array::LengthAtMost32; use core::cmp::{self, Ordering}; use core::fmt; use core::iter::{repeat_with, FromIterator, FusedIterator}; @@ -21,6 +22,9 @@ use crate::collections::CollectionAllocErr; use crate::raw_vec::RawVec; use crate::vec::Vec; +#[cfg(test)] +mod tests; + const INITIAL_CAPACITY: usize = 7; // 2^3 - 1 const MINIMUM_CAPACITY: usize = 1; // 2 - 1 #[cfg(target_pointer_width = "16")] @@ -96,7 +100,7 @@ impl<T> VecDeque<T> { // For zero sized types, we are always at maximum capacity MAXIMUM_ZST_CAPACITY } else { - self.buf.cap() + self.buf.capacity() } } @@ -312,10 +316,10 @@ impl<T> VecDeque<T> { } /// Frobs the head and tail sections around to handle the fact that we - /// just reallocated. Unsafe because it trusts old_cap. + /// just reallocated. Unsafe because it trusts old_capacity. #[inline] - unsafe fn handle_cap_increase(&mut self, old_cap: usize) { - let new_cap = self.cap(); + unsafe fn handle_capacity_increase(&mut self, old_capacity: usize) { + let new_capacity = self.cap(); // Move the shortest contiguous section of the ring buffer // T H @@ -334,15 +338,15 @@ impl<T> VecDeque<T> { if self.tail <= self.head { // A // Nop - } else if self.head < old_cap - self.tail { + } else if self.head < old_capacity - self.tail { // B - self.copy_nonoverlapping(old_cap, 0, self.head); - self.head += old_cap; + self.copy_nonoverlapping(old_capacity, 0, self.head); + self.head += old_capacity; debug_assert!(self.head > self.tail); } else { // C - let new_tail = new_cap - (old_cap - self.tail); - self.copy_nonoverlapping(new_tail, self.tail, old_cap - self.tail); + let new_tail = new_capacity - (old_capacity - self.tail); + self.copy_nonoverlapping(new_tail, self.tail, old_capacity - self.tail); self.tail = new_tail; debug_assert!(self.head < self.tail); } @@ -367,7 +371,7 @@ impl<T> VecDeque<T> { VecDeque::with_capacity(INITIAL_CAPACITY) } - /// Creates an empty `VecDeque` with space for at least `n` elements. + /// Creates an empty `VecDeque` with space for at least `capacity` elements. /// /// # Examples /// @@ -377,10 +381,10 @@ impl<T> VecDeque<T> { /// let vector: VecDeque<u32> = VecDeque::with_capacity(10); /// ``` #[stable(feature = "rust1", since = "1.0.0")] - pub fn with_capacity(n: usize) -> VecDeque<T> { + pub fn with_capacity(capacity: usize) -> VecDeque<T> { // +1 since the ringbuffer always leaves one space empty - let cap = cmp::max(n + 1, MINIMUM_CAPACITY + 1).next_power_of_two(); - assert!(cap > n, "capacity overflow"); + let cap = cmp::max(capacity + 1, MINIMUM_CAPACITY + 1).next_power_of_two(); + assert!(cap > capacity, "capacity overflow"); VecDeque { tail: 0, @@ -549,7 +553,7 @@ impl<T> VecDeque<T> { if new_cap > old_cap { self.buf.reserve_exact(used_cap, new_cap - used_cap); unsafe { - self.handle_cap_increase(old_cap); + self.handle_capacity_increase(old_cap); } } } @@ -639,7 +643,7 @@ impl<T> VecDeque<T> { if new_cap > old_cap { self.buf.try_reserve_exact(used_cap, new_cap - used_cap)?; unsafe { - self.handle_cap_increase(old_cap); + self.handle_capacity_increase(old_cap); } } Ok(()) @@ -1833,8 +1837,8 @@ impl<T> VecDeque<T> { /// Retains only the elements specified by the predicate. /// /// In other words, remove all elements `e` such that `f(&e)` returns false. - /// This method operates in place and preserves the order of the retained - /// elements. + /// This method operates in place, visiting each element exactly once in the + /// original order, and preserves the order of the retained elements. /// /// # Examples /// @@ -1846,6 +1850,20 @@ impl<T> VecDeque<T> { /// buf.retain(|&x| x%2 == 0); /// assert_eq!(buf, [2, 4]); /// ``` + /// + /// The exact order may be useful for tracking external state, like an index. + /// + /// ``` + /// use std::collections::VecDeque; + /// + /// let mut buf = VecDeque::new(); + /// buf.extend(1..6); + /// + /// let keep = [false, true, true, false, true]; + /// let mut i = 0; + /// buf.retain(|_| (keep[i], i += 1).0); + /// assert_eq!(buf, [2, 3, 5]); + /// ``` #[stable(feature = "vec_deque_retain", since = "1.4.0")] pub fn retain<F>(&mut self, mut f: F) where F: FnMut(&T) -> bool @@ -1871,7 +1889,7 @@ impl<T> VecDeque<T> { let old_cap = self.cap(); self.buf.double(); unsafe { - self.handle_cap_increase(old_cap); + self.handle_capacity_increase(old_cap); } debug_assert!(!self.is_full()); } @@ -1932,8 +1950,6 @@ impl<T> VecDeque<T> { /// # Examples /// /// ``` - /// #![feature(vecdeque_rotate)] - /// /// use std::collections::VecDeque; /// /// let mut buf: VecDeque<_> = (0..10).collect(); @@ -1947,7 +1963,7 @@ impl<T> VecDeque<T> { /// } /// assert_eq!(buf, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]); /// ``` - #[unstable(feature = "vecdeque_rotate", issue = "56686")] + #[stable(feature = "vecdeque_rotate", since = "1.36.0")] pub fn rotate_left(&mut self, mid: usize) { assert!(mid <= self.len()); let k = self.len() - mid; @@ -1977,8 +1993,6 @@ impl<T> VecDeque<T> { /// # Examples /// /// ``` - /// #![feature(vecdeque_rotate)] - /// /// use std::collections::VecDeque; /// /// let mut buf: VecDeque<_> = (0..10).collect(); @@ -1992,7 +2006,7 @@ impl<T> VecDeque<T> { /// } /// assert_eq!(buf, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]); /// ``` - #[unstable(feature = "vecdeque_rotate", issue = "56686")] + #[stable(feature = "vecdeque_rotate", since = "1.36.0")] pub fn rotate_right(&mut self, k: usize) { assert!(k <= self.len()); let mid = self.len() - k; @@ -2194,6 +2208,11 @@ impl<'a, T> Iterator for Iter<'a, T> { self.tail = self.head - iter.len(); final_res } + + #[inline] + fn last(mut self) -> Option<&'a T> { + self.next_back() + } } #[stable(feature = "rust1", since = "1.0.0")] @@ -2307,6 +2326,11 @@ impl<'a, T> Iterator for IterMut<'a, T> { accum = front.iter_mut().fold(accum, &mut f); back.iter_mut().fold(accum, &mut f) } + + #[inline] + fn last(mut self) -> Option<&'a mut T> { + self.next_back() + } } #[stable(feature = "rust1", since = "1.0.0")] @@ -2549,13 +2573,14 @@ impl<A: PartialEq> PartialEq for VecDeque<A> { impl<A: Eq> Eq for VecDeque<A> {} macro_rules! __impl_slice_eq1 { - ($Lhs: ty, $Rhs: ty) => { - __impl_slice_eq1! { $Lhs, $Rhs, Sized } - }; - ($Lhs: ty, $Rhs: ty, $Bound: ident) => { + ([$($vars:tt)*] $lhs:ty, $rhs:ty, $($constraints:tt)*) => { #[stable(feature = "vec_deque_partial_eq_slice", since = "1.17.0")] - impl<A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> { - fn eq(&self, other: &$Rhs) -> bool { + impl<A, B, $($vars)*> PartialEq<$rhs> for $lhs + where + A: PartialEq<B>, + $($constraints)* + { + fn eq(&self, other: &$rhs) -> bool { if self.len() != other.len() { return false; } @@ -2567,26 +2592,12 @@ macro_rules! __impl_slice_eq1 { } } -__impl_slice_eq1! { VecDeque<A>, Vec<B> } -__impl_slice_eq1! { VecDeque<A>, &[B] } -__impl_slice_eq1! { VecDeque<A>, &mut [B] } - -macro_rules! array_impls { - ($($N: expr)+) => { - $( - __impl_slice_eq1! { VecDeque<A>, [B; $N] } - __impl_slice_eq1! { VecDeque<A>, &[B; $N] } - __impl_slice_eq1! { VecDeque<A>, &mut [B; $N] } - )+ - } -} - -array_impls! { - 0 1 2 3 4 5 6 7 8 9 - 10 11 12 13 14 15 16 17 18 19 - 20 21 22 23 24 25 26 27 28 29 - 30 31 32 -} +__impl_slice_eq1! { [] VecDeque<A>, Vec<B>, } +__impl_slice_eq1! { [] VecDeque<A>, &[B], } +__impl_slice_eq1! { [] VecDeque<A>, &mut [B], } +__impl_slice_eq1! { [const N: usize] VecDeque<A>, [B; N], [B; N]: LengthAtMost32 } +__impl_slice_eq1! { [const N: usize] VecDeque<A>, &[B; N], [B; N]: LengthAtMost32 } +__impl_slice_eq1! { [const N: usize] VecDeque<A>, &mut [B; N], [B; N]: LengthAtMost32 } #[stable(feature = "rust1", since = "1.0.0")] impl<A: PartialOrd> PartialOrd for VecDeque<A> { @@ -2677,9 +2688,7 @@ impl<'a, T> IntoIterator for &'a mut VecDeque<T> { #[stable(feature = "rust1", since = "1.0.0")] impl<A> Extend<A> for VecDeque<A> { fn extend<T: IntoIterator<Item = A>>(&mut self, iter: T) { - for elt in iter { - self.push_back(elt); - } + iter.into_iter().for_each(move |elt| self.push_back(elt)); } } @@ -2699,6 +2708,14 @@ impl<T: fmt::Debug> fmt::Debug for VecDeque<T> { #[stable(feature = "vecdeque_vec_conversions", since = "1.10.0")] impl<T> From<Vec<T>> for VecDeque<T> { + /// Turn a [`Vec<T>`] into a [`VecDeque<T>`]. + /// + /// [`Vec<T>`]: crate::vec::Vec + /// [`VecDeque<T>`]: crate::collections::VecDeque + /// + /// This avoids reallocating where possible, but the conditions for that are + /// strict, and subject to change, and so shouldn't be relied upon unless the + /// `Vec<T>` came from `From<VecDeque<T>>` and hasn't been reallocated. fn from(mut other: Vec<T>) -> Self { unsafe { let other_buf = other.as_mut_ptr(); @@ -2708,9 +2725,9 @@ impl<T> From<Vec<T>> for VecDeque<T> { // We need to extend the buf if it's not a power of two, too small // or doesn't have at least one free space - if !buf.cap().is_power_of_two() || (buf.cap() < (MINIMUM_CAPACITY + 1)) || - (buf.cap() == len) { - let cap = cmp::max(buf.cap() + 1, MINIMUM_CAPACITY + 1).next_power_of_two(); + if !buf.capacity().is_power_of_two() || (buf.capacity() < (MINIMUM_CAPACITY + 1)) || + (buf.capacity() == len) { + let cap = cmp::max(buf.capacity() + 1, MINIMUM_CAPACITY + 1).next_power_of_two(); buf.reserve_exact(len, cap - len); } @@ -2725,6 +2742,35 @@ impl<T> From<Vec<T>> for VecDeque<T> { #[stable(feature = "vecdeque_vec_conversions", since = "1.10.0")] impl<T> From<VecDeque<T>> for Vec<T> { + /// Turn a [`VecDeque<T>`] into a [`Vec<T>`]. + /// + /// [`Vec<T>`]: crate::vec::Vec + /// [`VecDeque<T>`]: crate::collections::VecDeque + /// + /// This never needs to re-allocate, but does need to do O(n) data movement if + /// the circular buffer doesn't happen to be at the beginning of the allocation. + /// + /// # Examples + /// + /// ``` + /// use std::collections::VecDeque; + /// + /// // This one is O(1). + /// let deque: VecDeque<_> = (1..5).collect(); + /// let ptr = deque.as_slices().0.as_ptr(); + /// let vec = Vec::from(deque); + /// assert_eq!(vec, [1, 2, 3, 4]); + /// assert_eq!(vec.as_ptr(), ptr); + /// + /// // This one needs data rearranging. + /// let mut deque: VecDeque<_> = (1..5).collect(); + /// deque.push_front(9); + /// deque.push_front(8); + /// let ptr = deque.as_slices().1.as_ptr(); + /// let vec = Vec::from(deque); + /// assert_eq!(vec, [8, 9, 1, 2, 3, 4]); + /// assert_eq!(vec.as_ptr(), ptr); + /// ``` fn from(other: VecDeque<T>) -> Self { unsafe { let buf = other.buf.ptr(); @@ -2793,378 +2839,3 @@ impl<T> From<VecDeque<T>> for Vec<T> { } } } - -#[cfg(test)] -mod tests { - use ::test; - - use super::VecDeque; - - #[bench] - fn bench_push_back_100(b: &mut test::Bencher) { - let mut deq = VecDeque::with_capacity(101); - b.iter(|| { - for i in 0..100 { - deq.push_back(i); - } - deq.head = 0; - deq.tail = 0; - }) - } - - #[bench] - fn bench_push_front_100(b: &mut test::Bencher) { - let mut deq = VecDeque::with_capacity(101); - b.iter(|| { - for i in 0..100 { - deq.push_front(i); - } - deq.head = 0; - deq.tail = 0; - }) - } - - #[bench] - fn bench_pop_back_100(b: &mut test::Bencher) { - let mut deq = VecDeque::<i32>::with_capacity(101); - - b.iter(|| { - deq.head = 100; - deq.tail = 0; - while !deq.is_empty() { - test::black_box(deq.pop_back()); - } - }) - } - - #[bench] - fn bench_pop_front_100(b: &mut test::Bencher) { - let mut deq = VecDeque::<i32>::with_capacity(101); - - b.iter(|| { - deq.head = 100; - deq.tail = 0; - while !deq.is_empty() { - test::black_box(deq.pop_front()); - } - }) - } - - #[test] - fn test_swap_front_back_remove() { - fn test(back: bool) { - // This test checks that every single combination of tail position and length is tested. - // Capacity 15 should be large enough to cover every case. - let mut tester = VecDeque::with_capacity(15); - let usable_cap = tester.capacity(); - let final_len = usable_cap / 2; - - for len in 0..final_len { - let expected: VecDeque<_> = if back { - (0..len).collect() - } else { - (0..len).rev().collect() - }; - for tail_pos in 0..usable_cap { - tester.tail = tail_pos; - tester.head = tail_pos; - if back { - for i in 0..len * 2 { - tester.push_front(i); - } - for i in 0..len { - assert_eq!(tester.swap_remove_back(i), Some(len * 2 - 1 - i)); - } - } else { - for i in 0..len * 2 { - tester.push_back(i); - } - for i in 0..len { - let idx = tester.len() - 1 - i; - assert_eq!(tester.swap_remove_front(idx), Some(len * 2 - 1 - i)); - } - } - assert!(tester.tail < tester.cap()); - assert!(tester.head < tester.cap()); - assert_eq!(tester, expected); - } - } - } - test(true); - test(false); - } - - #[test] - fn test_insert() { - // This test checks that every single combination of tail position, length, and - // insertion position is tested. Capacity 15 should be large enough to cover every case. - - let mut tester = VecDeque::with_capacity(15); - // can't guarantee we got 15, so have to get what we got. - // 15 would be great, but we will definitely get 2^k - 1, for k >= 4, or else - // this test isn't covering what it wants to - let cap = tester.capacity(); - - - // len is the length *after* insertion - for len in 1..cap { - // 0, 1, 2, .., len - 1 - let expected = (0..).take(len).collect::<VecDeque<_>>(); - for tail_pos in 0..cap { - for to_insert in 0..len { - tester.tail = tail_pos; - tester.head = tail_pos; - for i in 0..len { - if i != to_insert { - tester.push_back(i); - } - } - tester.insert(to_insert, to_insert); - assert!(tester.tail < tester.cap()); - assert!(tester.head < tester.cap()); - assert_eq!(tester, expected); - } - } - } - } - - #[test] - fn test_remove() { - // This test checks that every single combination of tail position, length, and - // removal position is tested. Capacity 15 should be large enough to cover every case. - - let mut tester = VecDeque::with_capacity(15); - // can't guarantee we got 15, so have to get what we got. - // 15 would be great, but we will definitely get 2^k - 1, for k >= 4, or else - // this test isn't covering what it wants to - let cap = tester.capacity(); - - // len is the length *after* removal - for len in 0..cap - 1 { - // 0, 1, 2, .., len - 1 - let expected = (0..).take(len).collect::<VecDeque<_>>(); - for tail_pos in 0..cap { - for to_remove in 0..=len { - tester.tail = tail_pos; - tester.head = tail_pos; - for i in 0..len { - if i == to_remove { - tester.push_back(1234); - } - tester.push_back(i); - } - if to_remove == len { - tester.push_back(1234); - } - tester.remove(to_remove); - assert!(tester.tail < tester.cap()); - assert!(tester.head < tester.cap()); - assert_eq!(tester, expected); - } - } - } - } - - #[test] - fn test_drain() { - let mut tester: VecDeque<usize> = VecDeque::with_capacity(7); - - let cap = tester.capacity(); - for len in 0..=cap { - for tail in 0..=cap { - for drain_start in 0..=len { - for drain_end in drain_start..=len { - tester.tail = tail; - tester.head = tail; - for i in 0..len { - tester.push_back(i); - } - - // Check that we drain the correct values - let drained: VecDeque<_> = tester.drain(drain_start..drain_end).collect(); - let drained_expected: VecDeque<_> = (drain_start..drain_end).collect(); - assert_eq!(drained, drained_expected); - - // We shouldn't have changed the capacity or made the - // head or tail out of bounds - assert_eq!(tester.capacity(), cap); - assert!(tester.tail < tester.cap()); - assert!(tester.head < tester.cap()); - - // We should see the correct values in the VecDeque - let expected: VecDeque<_> = (0..drain_start) - .chain(drain_end..len) - .collect(); - assert_eq!(expected, tester); - } - } - } - } - } - - #[test] - fn test_shrink_to_fit() { - // This test checks that every single combination of head and tail position, - // is tested. Capacity 15 should be large enough to cover every case. - - let mut tester = VecDeque::with_capacity(15); - // can't guarantee we got 15, so have to get what we got. - // 15 would be great, but we will definitely get 2^k - 1, for k >= 4, or else - // this test isn't covering what it wants to - let cap = tester.capacity(); - tester.reserve(63); - let max_cap = tester.capacity(); - - for len in 0..=cap { - // 0, 1, 2, .., len - 1 - let expected = (0..).take(len).collect::<VecDeque<_>>(); - for tail_pos in 0..=max_cap { - tester.tail = tail_pos; - tester.head = tail_pos; - tester.reserve(63); - for i in 0..len { - tester.push_back(i); - } - tester.shrink_to_fit(); - assert!(tester.capacity() <= cap); - assert!(tester.tail < tester.cap()); - assert!(tester.head < tester.cap()); - assert_eq!(tester, expected); - } - } - } - - #[test] - fn test_split_off() { - // This test checks that every single combination of tail position, length, and - // split position is tested. Capacity 15 should be large enough to cover every case. - - let mut tester = VecDeque::with_capacity(15); - // can't guarantee we got 15, so have to get what we got. - // 15 would be great, but we will definitely get 2^k - 1, for k >= 4, or else - // this test isn't covering what it wants to - let cap = tester.capacity(); - - // len is the length *before* splitting - for len in 0..cap { - // index to split at - for at in 0..=len { - // 0, 1, 2, .., at - 1 (may be empty) - let expected_self = (0..).take(at).collect::<VecDeque<_>>(); - // at, at + 1, .., len - 1 (may be empty) - let expected_other = (at..).take(len - at).collect::<VecDeque<_>>(); - - for tail_pos in 0..cap { - tester.tail = tail_pos; - tester.head = tail_pos; - for i in 0..len { - tester.push_back(i); - } - let result = tester.split_off(at); - assert!(tester.tail < tester.cap()); - assert!(tester.head < tester.cap()); - assert!(result.tail < result.cap()); - assert!(result.head < result.cap()); - assert_eq!(tester, expected_self); - assert_eq!(result, expected_other); - } - } - } - } - - #[test] - fn test_from_vec() { - use crate::vec::Vec; - for cap in 0..35 { - for len in 0..=cap { - let mut vec = Vec::with_capacity(cap); - vec.extend(0..len); - - let vd = VecDeque::from(vec.clone()); - assert!(vd.cap().is_power_of_two()); - assert_eq!(vd.len(), vec.len()); - assert!(vd.into_iter().eq(vec)); - } - } - } - - #[test] - fn test_vec_from_vecdeque() { - use crate::vec::Vec; - - fn create_vec_and_test_convert(cap: usize, offset: usize, len: usize) { - let mut vd = VecDeque::with_capacity(cap); - for _ in 0..offset { - vd.push_back(0); - vd.pop_front(); - } - vd.extend(0..len); - - let vec: Vec<_> = Vec::from(vd.clone()); - assert_eq!(vec.len(), vd.len()); - assert!(vec.into_iter().eq(vd)); - } - - for cap_pwr in 0..7 { - // Make capacity as a (2^x)-1, so that the ring size is 2^x - let cap = (2i32.pow(cap_pwr) - 1) as usize; - - // In these cases there is enough free space to solve it with copies - for len in 0..((cap + 1) / 2) { - // Test contiguous cases - for offset in 0..(cap - len) { - create_vec_and_test_convert(cap, offset, len) - } - - // Test cases where block at end of buffer is bigger than block at start - for offset in (cap - len)..(cap - (len / 2)) { - create_vec_and_test_convert(cap, offset, len) - } - - // Test cases where block at start of buffer is bigger than block at end - for offset in (cap - (len / 2))..cap { - create_vec_and_test_convert(cap, offset, len) - } - } - - // Now there's not (necessarily) space to straighten the ring with simple copies, - // the ring will use swapping when: - // (cap + 1 - offset) > (cap + 1 - len) && (len - (cap + 1 - offset)) > (cap + 1 - len)) - // right block size > free space && left block size > free space - for len in ((cap + 1) / 2)..cap { - // Test contiguous cases - for offset in 0..(cap - len) { - create_vec_and_test_convert(cap, offset, len) - } - - // Test cases where block at end of buffer is bigger than block at start - for offset in (cap - len)..(cap - (len / 2)) { - create_vec_and_test_convert(cap, offset, len) - } - - // Test cases where block at start of buffer is bigger than block at end - for offset in (cap - (len / 2))..cap { - create_vec_and_test_convert(cap, offset, len) - } - } - } - } - - #[test] - fn issue_53529() { - use crate::boxed::Box; - - let mut dst = VecDeque::new(); - dst.push_front(Box::new(1)); - dst.push_front(Box::new(2)); - assert_eq!(*dst.pop_back().unwrap(), 1); - - let mut src = VecDeque::new(); - src.push_front(Box::new(2)); - dst.append(&mut src); - for a in dst { - assert_eq!(*a, 2); - } - } - -} diff --git a/src/liballoc/collections/vec_deque/tests.rs b/src/liballoc/collections/vec_deque/tests.rs new file mode 100644 index 00000000000..d2535239979 --- /dev/null +++ b/src/liballoc/collections/vec_deque/tests.rs @@ -0,0 +1,379 @@ +use super::*; + +use ::test; + +#[bench] +#[cfg(not(miri))] // Miri does not support benchmarks +fn bench_push_back_100(b: &mut test::Bencher) { + let mut deq = VecDeque::with_capacity(101); + b.iter(|| { + for i in 0..100 { + deq.push_back(i); + } + deq.head = 0; + deq.tail = 0; + }) +} + +#[bench] +#[cfg(not(miri))] // Miri does not support benchmarks +fn bench_push_front_100(b: &mut test::Bencher) { + let mut deq = VecDeque::with_capacity(101); + b.iter(|| { + for i in 0..100 { + deq.push_front(i); + } + deq.head = 0; + deq.tail = 0; + }) +} + +#[bench] +#[cfg(not(miri))] // Miri does not support benchmarks +fn bench_pop_back_100(b: &mut test::Bencher) { + let mut deq = VecDeque::<i32>::with_capacity(101); + + b.iter(|| { + deq.head = 100; + deq.tail = 0; + while !deq.is_empty() { + test::black_box(deq.pop_back()); + } + }) +} + +#[bench] +#[cfg(not(miri))] // Miri does not support benchmarks +fn bench_pop_front_100(b: &mut test::Bencher) { + let mut deq = VecDeque::<i32>::with_capacity(101); + + b.iter(|| { + deq.head = 100; + deq.tail = 0; + while !deq.is_empty() { + test::black_box(deq.pop_front()); + } + }) +} + +#[test] +fn test_swap_front_back_remove() { + fn test(back: bool) { + // This test checks that every single combination of tail position and length is tested. + // Capacity 15 should be large enough to cover every case. + let mut tester = VecDeque::with_capacity(15); + let usable_cap = tester.capacity(); + let final_len = usable_cap / 2; + + for len in 0..final_len { + let expected: VecDeque<_> = if back { + (0..len).collect() + } else { + (0..len).rev().collect() + }; + for tail_pos in 0..usable_cap { + tester.tail = tail_pos; + tester.head = tail_pos; + if back { + for i in 0..len * 2 { + tester.push_front(i); + } + for i in 0..len { + assert_eq!(tester.swap_remove_back(i), Some(len * 2 - 1 - i)); + } + } else { + for i in 0..len * 2 { + tester.push_back(i); + } + for i in 0..len { + let idx = tester.len() - 1 - i; + assert_eq!(tester.swap_remove_front(idx), Some(len * 2 - 1 - i)); + } + } + assert!(tester.tail < tester.cap()); + assert!(tester.head < tester.cap()); + assert_eq!(tester, expected); + } + } + } + test(true); + test(false); +} + +#[test] +fn test_insert() { + // This test checks that every single combination of tail position, length, and + // insertion position is tested. Capacity 15 should be large enough to cover every case. + + let mut tester = VecDeque::with_capacity(15); + // can't guarantee we got 15, so have to get what we got. + // 15 would be great, but we will definitely get 2^k - 1, for k >= 4, or else + // this test isn't covering what it wants to + let cap = tester.capacity(); + + + // len is the length *after* insertion + for len in 1..cap { + // 0, 1, 2, .., len - 1 + let expected = (0..).take(len).collect::<VecDeque<_>>(); + for tail_pos in 0..cap { + for to_insert in 0..len { + tester.tail = tail_pos; + tester.head = tail_pos; + for i in 0..len { + if i != to_insert { + tester.push_back(i); + } + } + tester.insert(to_insert, to_insert); + assert!(tester.tail < tester.cap()); + assert!(tester.head < tester.cap()); + assert_eq!(tester, expected); + } + } + } +} + +#[test] +fn test_remove() { + // This test checks that every single combination of tail position, length, and + // removal position is tested. Capacity 15 should be large enough to cover every case. + + let mut tester = VecDeque::with_capacity(15); + // can't guarantee we got 15, so have to get what we got. + // 15 would be great, but we will definitely get 2^k - 1, for k >= 4, or else + // this test isn't covering what it wants to + let cap = tester.capacity(); + + // len is the length *after* removal + for len in 0..cap - 1 { + // 0, 1, 2, .., len - 1 + let expected = (0..).take(len).collect::<VecDeque<_>>(); + for tail_pos in 0..cap { + for to_remove in 0..=len { + tester.tail = tail_pos; + tester.head = tail_pos; + for i in 0..len { + if i == to_remove { + tester.push_back(1234); + } + tester.push_back(i); + } + if to_remove == len { + tester.push_back(1234); + } + tester.remove(to_remove); + assert!(tester.tail < tester.cap()); + assert!(tester.head < tester.cap()); + assert_eq!(tester, expected); + } + } + } +} + +#[test] +fn test_drain() { + let mut tester: VecDeque<usize> = VecDeque::with_capacity(7); + + let cap = tester.capacity(); + for len in 0..=cap { + for tail in 0..=cap { + for drain_start in 0..=len { + for drain_end in drain_start..=len { + tester.tail = tail; + tester.head = tail; + for i in 0..len { + tester.push_back(i); + } + + // Check that we drain the correct values + let drained: VecDeque<_> = tester.drain(drain_start..drain_end).collect(); + let drained_expected: VecDeque<_> = (drain_start..drain_end).collect(); + assert_eq!(drained, drained_expected); + + // We shouldn't have changed the capacity or made the + // head or tail out of bounds + assert_eq!(tester.capacity(), cap); + assert!(tester.tail < tester.cap()); + assert!(tester.head < tester.cap()); + + // We should see the correct values in the VecDeque + let expected: VecDeque<_> = (0..drain_start) + .chain(drain_end..len) + .collect(); + assert_eq!(expected, tester); + } + } + } + } +} + +#[test] +fn test_shrink_to_fit() { + // This test checks that every single combination of head and tail position, + // is tested. Capacity 15 should be large enough to cover every case. + + let mut tester = VecDeque::with_capacity(15); + // can't guarantee we got 15, so have to get what we got. + // 15 would be great, but we will definitely get 2^k - 1, for k >= 4, or else + // this test isn't covering what it wants to + let cap = tester.capacity(); + tester.reserve(63); + let max_cap = tester.capacity(); + + for len in 0..=cap { + // 0, 1, 2, .., len - 1 + let expected = (0..).take(len).collect::<VecDeque<_>>(); + for tail_pos in 0..=max_cap { + tester.tail = tail_pos; + tester.head = tail_pos; + tester.reserve(63); + for i in 0..len { + tester.push_back(i); + } + tester.shrink_to_fit(); + assert!(tester.capacity() <= cap); + assert!(tester.tail < tester.cap()); + assert!(tester.head < tester.cap()); + assert_eq!(tester, expected); + } + } +} + +#[test] +fn test_split_off() { + // This test checks that every single combination of tail position, length, and + // split position is tested. Capacity 15 should be large enough to cover every case. + + let mut tester = VecDeque::with_capacity(15); + // can't guarantee we got 15, so have to get what we got. + // 15 would be great, but we will definitely get 2^k - 1, for k >= 4, or else + // this test isn't covering what it wants to + let cap = tester.capacity(); + + // len is the length *before* splitting + for len in 0..cap { + // index to split at + for at in 0..=len { + // 0, 1, 2, .., at - 1 (may be empty) + let expected_self = (0..).take(at).collect::<VecDeque<_>>(); + // at, at + 1, .., len - 1 (may be empty) + let expected_other = (at..).take(len - at).collect::<VecDeque<_>>(); + + for tail_pos in 0..cap { + tester.tail = tail_pos; + tester.head = tail_pos; + for i in 0..len { + tester.push_back(i); + } + let result = tester.split_off(at); + assert!(tester.tail < tester.cap()); + assert!(tester.head < tester.cap()); + assert!(result.tail < result.cap()); + assert!(result.head < result.cap()); + assert_eq!(tester, expected_self); + assert_eq!(result, expected_other); + } + } + } +} + +#[test] +fn test_from_vec() { + use crate::vec::Vec; + for cap in 0..35 { + for len in 0..=cap { + let mut vec = Vec::with_capacity(cap); + vec.extend(0..len); + + let vd = VecDeque::from(vec.clone()); + assert!(vd.cap().is_power_of_two()); + assert_eq!(vd.len(), vec.len()); + assert!(vd.into_iter().eq(vec)); + } + } +} + +#[test] +fn test_vec_from_vecdeque() { + use crate::vec::Vec; + + fn create_vec_and_test_convert(capacity: usize, offset: usize, len: usize) { + let mut vd = VecDeque::with_capacity(capacity); + for _ in 0..offset { + vd.push_back(0); + vd.pop_front(); + } + vd.extend(0..len); + + let vec: Vec<_> = Vec::from(vd.clone()); + assert_eq!(vec.len(), vd.len()); + assert!(vec.into_iter().eq(vd)); + } + + #[cfg(not(miri))] // Miri is too slow + let max_pwr = 7; + #[cfg(miri)] + let max_pwr = 5; + + for cap_pwr in 0..max_pwr { + // Make capacity as a (2^x)-1, so that the ring size is 2^x + let cap = (2i32.pow(cap_pwr) - 1) as usize; + + // In these cases there is enough free space to solve it with copies + for len in 0..((cap + 1) / 2) { + // Test contiguous cases + for offset in 0..(cap - len) { + create_vec_and_test_convert(cap, offset, len) + } + + // Test cases where block at end of buffer is bigger than block at start + for offset in (cap - len)..(cap - (len / 2)) { + create_vec_and_test_convert(cap, offset, len) + } + + // Test cases where block at start of buffer is bigger than block at end + for offset in (cap - (len / 2))..cap { + create_vec_and_test_convert(cap, offset, len) + } + } + + // Now there's not (necessarily) space to straighten the ring with simple copies, + // the ring will use swapping when: + // (cap + 1 - offset) > (cap + 1 - len) && (len - (cap + 1 - offset)) > (cap + 1 - len)) + // right block size > free space && left block size > free space + for len in ((cap + 1) / 2)..cap { + // Test contiguous cases + for offset in 0..(cap - len) { + create_vec_and_test_convert(cap, offset, len) + } + + // Test cases where block at end of buffer is bigger than block at start + for offset in (cap - len)..(cap - (len / 2)) { + create_vec_and_test_convert(cap, offset, len) + } + + // Test cases where block at start of buffer is bigger than block at end + for offset in (cap - (len / 2))..cap { + create_vec_and_test_convert(cap, offset, len) + } + } + } +} + +#[test] +fn issue_53529() { + use crate::boxed::Box; + + let mut dst = VecDeque::new(); + dst.push_front(Box::new(1)); + dst.push_front(Box::new(2)); + assert_eq!(*dst.pop_back().unwrap(), 1); + + let mut src = VecDeque::new(); + src.push_front(Box::new(2)); + dst.append(&mut src); + for a in dst { + assert_eq!(*a, 2); + } +} diff --git a/src/liballoc/fmt.rs b/src/liballoc/fmt.rs index d2ba9b00191..68cbc366d7b 100644 --- a/src/liballoc/fmt.rs +++ b/src/liballoc/fmt.rs @@ -343,9 +343,10 @@ //! * `^` - the argument is center-aligned in `width` columns //! * `>` - the argument is right-aligned in `width` columns //! -//! Note that alignment may not be implemented by some types. A good way -//! to ensure padding is applied is to format your input, then use this -//! resulting string to pad your output. +//! Note that alignment may not be implemented by some types. In particular, it +//! is not generally implemented for the `Debug` trait. A good way to ensure +//! padding is applied is to format your input, then use this resulting string +//! to pad your output. //! //! ## Sign/`#`/`0` //! diff --git a/src/liballoc/lib.rs b/src/liballoc/lib.rs index 440ce8ac5e8..deea74daa52 100644 --- a/src/liballoc/lib.rs +++ b/src/liballoc/lib.rs @@ -10,9 +10,9 @@ //! //! ## Boxed values //! -//! The [`Box`](boxed/index.html) type is a smart pointer type. There can -//! only be one owner of a `Box`, and the owner can decide to mutate the -//! contents, which live on the heap. +//! The [`Box`] type is a smart pointer type. There can only be one owner of a +//! [`Box`], and the owner can decide to mutate the contents, which live on the +//! heap. //! //! This type can be sent among threads efficiently as the size of a `Box` value //! is the same as that of a pointer. Tree-like data structures are often built @@ -20,20 +20,20 @@ //! //! ## Reference counted pointers //! -//! The [`Rc`](rc/index.html) type is a non-threadsafe reference-counted pointer -//! type intended for sharing memory within a thread. An `Rc` pointer wraps a -//! type, `T`, and only allows access to `&T`, a shared reference. +//! The [`Rc`] type is a non-threadsafe reference-counted pointer type intended +//! for sharing memory within a thread. An [`Rc`] pointer wraps a type, `T`, and +//! only allows access to `&T`, a shared reference. //! -//! This type is useful when inherited mutability (such as using `Box`) is too -//! constraining for an application, and is often paired with the `Cell` or -//! `RefCell` types in order to allow mutation. +//! This type is useful when inherited mutability (such as using [`Box`]) is too +//! constraining for an application, and is often paired with the [`Cell`] or +//! [`RefCell`] types in order to allow mutation. //! //! ## Atomically reference counted pointers //! -//! The [`Arc`](sync/index.html) type is the threadsafe equivalent of the `Rc` -//! type. It provides all the same functionality of `Rc`, except it requires -//! that the contained type `T` is shareable. Additionally, `Arc<T>` is itself -//! sendable while `Rc<T>` is not. +//! The [`Arc`] type is the threadsafe equivalent of the [`Rc`] type. It +//! provides all the same functionality of [`Rc`], except it requires that the +//! contained type `T` is shareable. Additionally, [`Arc<T>`][`Arc`] is itself +//! sendable while [`Rc<T>`][`Rc`] is not. //! //! This type allows for shared access to the contained data, and is often //! paired with synchronization primitives such as mutexes to allow mutation of @@ -49,24 +49,27 @@ //! //! The [`alloc`](alloc/index.html) module defines the low-level interface to the //! default global allocator. It is not compatible with the libc allocator API. +//! +//! [`Arc`]: sync/index.html +//! [`Box`]: boxed/index.html +//! [`Cell`]: ../core/cell/index.html +//! [`Rc`]: rc/index.html +//! [`RefCell`]: ../core/cell/index.html #![allow(unused_attributes)] -#![unstable(feature = "alloc", - reason = "this library is unlikely to be stabilized in its current \ - form or name", - issue = "27783")] +#![stable(feature = "alloc", since = "1.36.0")] #![doc(html_root_url = "https://doc.rust-lang.org/nightly/", issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/", test(no_crate_inject, attr(allow(unused_variables), deny(warnings))))] #![no_std] #![needs_allocator] -#![deny(rust_2018_idioms)] -#![allow(explicit_outlives_requirements)] - #![warn(deprecated_in_future)] -#![warn(intra_doc_link_resolution_failure)] +#![warn(missing_docs)] #![warn(missing_debug_implementations)] +#![deny(intra_doc_link_resolution_failure)] // rustdoc is run without -D warnings +#![allow(explicit_outlives_requirements)] +#![cfg_attr(not(bootstrap), allow(incomplete_features))] #![cfg_attr(not(test), feature(generator_trait))] #![cfg_attr(test, feature(test))] @@ -79,18 +82,19 @@ #![feature(box_syntax)] #![feature(cfg_target_has_atomic)] #![feature(coerce_unsized)] +#![feature(const_generic_impls_guard)] +#![feature(const_generics)] +#![cfg_attr(not(bootstrap), feature(const_in_array_repeat_expressions))] #![feature(dispatch_from_dyn)] #![feature(core_intrinsics)] -#![feature(custom_attribute)] #![feature(dropck_eyepatch)] #![feature(exact_size_is_empty)] #![feature(fmt_internals)] #![feature(fn_traits)] #![feature(fundamental)] -#![feature(futures_api)] +#![feature(internal_uninit_const)] #![feature(lang_items)] #![feature(libc)] -#![feature(needs_allocator)] #![feature(nll)] #![feature(optin_builtin_traits)] #![feature(pattern)] @@ -98,6 +102,7 @@ #![feature(ptr_offset_from)] #![feature(rustc_attrs)] #![feature(receiver_trait)] +#![feature(slice_from_raw_parts)] #![feature(specialization)] #![feature(staged_api)] #![feature(std_internals)] @@ -107,14 +112,16 @@ #![feature(unboxed_closures)] #![feature(unicode_internals)] #![feature(unsize)] +#![feature(unsized_locals)] #![feature(allocator_internals)] #![feature(on_unimplemented)] #![feature(rustc_const_unstable)] #![feature(const_vec_new)] #![feature(slice_partition_dedup)] -#![feature(maybe_uninit, maybe_uninit_slice, maybe_uninit_array)] +#![feature(maybe_uninit_extra, maybe_uninit_slice, maybe_uninit_array)] #![feature(alloc_layout_extra)] #![feature(try_trait)] +#![feature(mem_take)] // Allow testing this library @@ -144,7 +151,7 @@ mod boxed { pub use std::boxed::Box; } #[cfg(test)] -mod boxed_test; +mod tests; pub mod collections; #[cfg(all(target_has_atomic = "ptr", target_has_atomic = "cas"))] pub mod sync; diff --git a/src/liballoc/macros.rs b/src/liballoc/macros.rs index dd128e096f9..250c419c531 100644 --- a/src/liballoc/macros.rs +++ b/src/liballoc/macros.rs @@ -42,7 +42,7 @@ macro_rules! vec { ($($x:expr),*) => ( <[_]>::into_vec(box [$($x),*]) ); - ($($x:expr,)*) => (vec![$($x),*]) + ($($x:expr,)*) => ($crate::vec![$($x),*]) } // HACK(japaric): with cfg(test) the inherent `[T]::into_vec` method, which is diff --git a/src/liballoc/prelude.rs b/src/liballoc/prelude.rs deleted file mode 100644 index 6767cf89f73..00000000000 --- a/src/liballoc/prelude.rs +++ /dev/null @@ -1,19 +0,0 @@ -//! The alloc Prelude -//! -//! The purpose of this module is to alleviate imports of commonly-used -//! items of the `alloc` crate by adding a glob import to the top of modules: -//! -//! ``` -//! # #![allow(unused_imports)] -//! # #![feature(alloc)] -//! extern crate alloc; -//! use alloc::prelude::*; -//! ``` - -#![unstable(feature = "alloc", issue = "27783")] - -#[unstable(feature = "alloc", issue = "27783")] pub use crate::borrow::ToOwned; -#[unstable(feature = "alloc", issue = "27783")] pub use crate::boxed::Box; -#[unstable(feature = "alloc", issue = "27783")] pub use crate::slice::SliceConcatExt; -#[unstable(feature = "alloc", issue = "27783")] pub use crate::string::{String, ToString}; -#[unstable(feature = "alloc", issue = "27783")] pub use crate::vec::Vec; diff --git a/src/liballoc/prelude/mod.rs b/src/liballoc/prelude/mod.rs new file mode 100644 index 00000000000..0534ad3edc7 --- /dev/null +++ b/src/liballoc/prelude/mod.rs @@ -0,0 +1,15 @@ +//! The alloc Prelude +//! +//! The purpose of this module is to alleviate imports of commonly-used +//! items of the `alloc` crate by adding a glob import to the top of modules: +//! +//! ``` +//! # #![allow(unused_imports)] +//! #![feature(alloc_prelude)] +//! extern crate alloc; +//! use alloc::prelude::v1::*; +//! ``` + +#![unstable(feature = "alloc_prelude", issue = "58935")] + +pub mod v1; diff --git a/src/liballoc/prelude/v1.rs b/src/liballoc/prelude/v1.rs new file mode 100644 index 00000000000..3cb285bf049 --- /dev/null +++ b/src/liballoc/prelude/v1.rs @@ -0,0 +1,10 @@ +//! The first version of the prelude of `alloc` crate. +//! +//! See the [module-level documentation](../index.html) for more. + +#![unstable(feature = "alloc_prelude", issue = "58935")] + +#[unstable(feature = "alloc_prelude", issue = "58935")] pub use crate::borrow::ToOwned; +#[unstable(feature = "alloc_prelude", issue = "58935")] pub use crate::boxed::Box; +#[unstable(feature = "alloc_prelude", issue = "58935")] pub use crate::string::{String, ToString}; +#[unstable(feature = "alloc_prelude", issue = "58935")] pub use crate::vec::Vec; diff --git a/src/liballoc/raw_vec.rs b/src/liballoc/raw_vec.rs index fe28fe5095c..0abab45e920 100644 --- a/src/liballoc/raw_vec.rs +++ b/src/liballoc/raw_vec.rs @@ -11,6 +11,9 @@ use crate::alloc::{Alloc, Layout, Global, handle_alloc_error}; use crate::collections::CollectionAllocErr::{self, *}; use crate::boxed::Box; +#[cfg(test)] +mod tests; + /// A low-level utility for more ergonomically allocating, reallocating, and deallocating /// a buffer of memory on the heap without having to worry about all the corner cases /// involved. This type is excellent for building your own data structures like Vec and VecDeque. @@ -34,7 +37,7 @@ use crate::boxed::Box; /// that might occur with zero-sized types. /// /// However this means that you need to be careful when round-tripping this type -/// with a `Box<[T]>`: `cap()` won't yield the len. However `with_capacity`, +/// with a `Box<[T]>`: `capacity()` won't yield the len. However `with_capacity`, /// `shrink_to_fit`, and `from_box` will actually set RawVec's private capacity /// field. This allows zero-sized types to not be special-cased by consumers of /// this type. @@ -65,25 +68,25 @@ impl<T, A: Alloc> RawVec<T, A> { /// Like `with_capacity` but parameterized over the choice of /// allocator for the returned RawVec. #[inline] - pub fn with_capacity_in(cap: usize, a: A) -> Self { - RawVec::allocate_in(cap, false, a) + pub fn with_capacity_in(capacity: usize, a: A) -> Self { + RawVec::allocate_in(capacity, false, a) } /// Like `with_capacity_zeroed` but parameterized over the choice /// of allocator for the returned RawVec. #[inline] - pub fn with_capacity_zeroed_in(cap: usize, a: A) -> Self { - RawVec::allocate_in(cap, true, a) + pub fn with_capacity_zeroed_in(capacity: usize, a: A) -> Self { + RawVec::allocate_in(capacity, true, a) } - fn allocate_in(cap: usize, zeroed: bool, mut a: A) -> Self { + fn allocate_in(capacity: usize, zeroed: bool, mut a: A) -> Self { unsafe { let elem_size = mem::size_of::<T>(); - let alloc_size = cap.checked_mul(elem_size).unwrap_or_else(|| capacity_overflow()); + let alloc_size = capacity.checked_mul(elem_size).unwrap_or_else(|| capacity_overflow()); alloc_guard(alloc_size).unwrap_or_else(|_| capacity_overflow()); - // handles ZSTs and `cap = 0` alike + // handles ZSTs and `capacity = 0` alike let ptr = if alloc_size == 0 { NonNull::<T>::dangling() } else { @@ -102,7 +105,7 @@ impl<T, A: Alloc> RawVec<T, A> { RawVec { ptr: ptr.into(), - cap, + cap: capacity, a, } } @@ -120,8 +123,8 @@ impl<T> RawVec<T, Global> { } /// Creates a RawVec (on the system heap) with exactly the - /// capacity and alignment requirements for a `[T; cap]`. This is - /// equivalent to calling RawVec::new when `cap` is 0 or T is + /// capacity and alignment requirements for a `[T; capacity]`. This is + /// equivalent to calling RawVec::new when `capacity` is 0 or T is /// zero-sized. Note that if `T` is zero-sized this means you will /// *not* get a RawVec with the requested capacity! /// @@ -135,14 +138,14 @@ impl<T> RawVec<T, Global> { /// /// Aborts on OOM #[inline] - pub fn with_capacity(cap: usize) -> Self { - RawVec::allocate_in(cap, false, Global) + pub fn with_capacity(capacity: usize) -> Self { + RawVec::allocate_in(capacity, false, Global) } /// Like `with_capacity` but guarantees the buffer is zeroed. #[inline] - pub fn with_capacity_zeroed(cap: usize) -> Self { - RawVec::allocate_in(cap, true, Global) + pub fn with_capacity_zeroed(capacity: usize) -> Self { + RawVec::allocate_in(capacity, true, Global) } } @@ -154,10 +157,10 @@ impl<T, A: Alloc> RawVec<T, A> { /// The ptr must be allocated (via the given allocator `a`), and with the given capacity. The /// capacity cannot exceed `isize::MAX` (only a concern on 32-bit systems). /// If the ptr and capacity come from a RawVec created via `a`, then this is guaranteed. - pub unsafe fn from_raw_parts_in(ptr: *mut T, cap: usize, a: A) -> Self { + pub unsafe fn from_raw_parts_in(ptr: *mut T, capacity: usize, a: A) -> Self { RawVec { ptr: Unique::new_unchecked(ptr), - cap, + cap: capacity, a, } } @@ -171,10 +174,10 @@ impl<T> RawVec<T, Global> { /// The ptr must be allocated (on the system heap), and with the given capacity. The /// capacity cannot exceed `isize::MAX` (only a concern on 32-bit systems). /// If the ptr and capacity come from a RawVec, then this is guaranteed. - pub unsafe fn from_raw_parts(ptr: *mut T, cap: usize) -> Self { + pub unsafe fn from_raw_parts(ptr: *mut T, capacity: usize) -> Self { RawVec { ptr: Unique::new_unchecked(ptr), - cap, + cap: capacity, a: Global, } } @@ -191,7 +194,7 @@ impl<T> RawVec<T, Global> { impl<T, A: Alloc> RawVec<T, A> { /// Gets a raw pointer to the start of the allocation. Note that this is - /// Unique::empty() if `cap = 0` or T is zero-sized. In the former case, you must + /// Unique::empty() if `capacity = 0` or T is zero-sized. In the former case, you must /// be careful. pub fn ptr(&self) -> *mut T { self.ptr.as_ptr() @@ -201,7 +204,7 @@ impl<T, A: Alloc> RawVec<T, A> { /// /// This will always be `usize::MAX` if `T` is zero-sized. #[inline(always)] - pub fn cap(&self) -> usize { + pub fn capacity(&self) -> usize { if mem::size_of::<T>() == 0 { !0 } else { @@ -240,7 +243,7 @@ impl<T, A: Alloc> RawVec<T, A> { /// This function is ideal for when pushing elements one-at-a-time because /// you don't need to incur the costs of the more general computations /// reserve needs to do to guard against overflow. You do however need to - /// manually check if your `len == cap`. + /// manually check if your `len == capacity`. /// /// # Panics /// @@ -256,7 +259,7 @@ impl<T, A: Alloc> RawVec<T, A> { /// # Examples /// /// ``` - /// # #![feature(alloc, raw_vec_internals)] + /// # #![feature(raw_vec_internals)] /// # extern crate alloc; /// # use std::ptr; /// # use alloc::raw_vec::RawVec; @@ -267,7 +270,7 @@ impl<T, A: Alloc> RawVec<T, A> { /// /// impl<T> MyVec<T> { /// pub fn push(&mut self, elem: T) { - /// if self.len == self.buf.cap() { self.buf.double(); } + /// if self.len == self.buf.capacity() { self.buf.double(); } /// // double would have aborted or panicked if the len exceeded /// // `isize::MAX` so this is safe to do unchecked now. /// unsafe { @@ -381,20 +384,20 @@ impl<T, A: Alloc> RawVec<T, A> { } /// The same as `reserve_exact`, but returns on errors instead of panicking or aborting. - pub fn try_reserve_exact(&mut self, used_cap: usize, needed_extra_cap: usize) + pub fn try_reserve_exact(&mut self, used_capacity: usize, needed_extra_capacity: usize) -> Result<(), CollectionAllocErr> { - self.reserve_internal(used_cap, needed_extra_cap, Fallible, Exact) + self.reserve_internal(used_capacity, needed_extra_capacity, Fallible, Exact) } /// Ensures that the buffer contains at least enough space to hold - /// `used_cap + needed_extra_cap` elements. If it doesn't already, + /// `used_capacity + needed_extra_capacity` elements. If it doesn't already, /// will reallocate the minimum possible amount of memory necessary. /// Generally this will be exactly the amount of memory necessary, /// but in principle the allocator is free to give back more than /// we asked for. /// - /// If `used_cap` exceeds `self.cap()`, this may fail to actually allocate + /// If `used_capacity` exceeds `self.capacity()`, this may fail to actually allocate /// the requested space. This is not really unsafe, but the unsafe /// code *you* write that relies on the behavior of this function may break. /// @@ -407,22 +410,23 @@ impl<T, A: Alloc> RawVec<T, A> { /// # Aborts /// /// Aborts on OOM - pub fn reserve_exact(&mut self, used_cap: usize, needed_extra_cap: usize) { - match self.reserve_internal(used_cap, needed_extra_cap, Infallible, Exact) { + pub fn reserve_exact(&mut self, used_capacity: usize, needed_extra_capacity: usize) { + match self.reserve_internal(used_capacity, needed_extra_capacity, Infallible, Exact) { Err(CapacityOverflow) => capacity_overflow(), Err(AllocErr) => unreachable!(), Ok(()) => { /* yay */ } } } - /// Calculates the buffer's new size given that it'll hold `used_cap + - /// needed_extra_cap` elements. This logic is used in amortized reserve methods. + /// Calculates the buffer's new size given that it'll hold `used_capacity + + /// needed_extra_capacity` elements. This logic is used in amortized reserve methods. /// Returns `(new_capacity, new_alloc_size)`. - fn amortized_new_size(&self, used_cap: usize, needed_extra_cap: usize) + fn amortized_new_size(&self, used_capacity: usize, needed_extra_capacity: usize) -> Result<usize, CollectionAllocErr> { // Nothing we can really do about these checks :( - let required_cap = used_cap.checked_add(needed_extra_cap).ok_or(CapacityOverflow)?; + let required_cap = used_capacity.checked_add(needed_extra_capacity) + .ok_or(CapacityOverflow)?; // Cannot overflow, because `cap <= isize::MAX`, and type of `cap` is `usize`. let double_cap = self.cap * 2; // `double_cap` guarantees exponential growth. @@ -430,18 +434,18 @@ impl<T, A: Alloc> RawVec<T, A> { } /// The same as `reserve`, but returns on errors instead of panicking or aborting. - pub fn try_reserve(&mut self, used_cap: usize, needed_extra_cap: usize) + pub fn try_reserve(&mut self, used_capacity: usize, needed_extra_capacity: usize) -> Result<(), CollectionAllocErr> { - self.reserve_internal(used_cap, needed_extra_cap, Fallible, Amortized) + self.reserve_internal(used_capacity, needed_extra_capacity, Fallible, Amortized) } /// Ensures that the buffer contains at least enough space to hold - /// `used_cap + needed_extra_cap` elements. If it doesn't already have + /// `used_capacity + needed_extra_capacity` elements. If it doesn't already have /// enough capacity, will reallocate enough space plus comfortable slack /// space to get amortized `O(1)` behavior. Will limit this behavior /// if it would needlessly cause itself to panic. /// - /// If `used_cap` exceeds `self.cap()`, this may fail to actually allocate + /// If `used_capacity` exceeds `self.capacity()`, this may fail to actually allocate /// the requested space. This is not really unsafe, but the unsafe /// code *you* write that relies on the behavior of this function may break. /// @@ -460,7 +464,7 @@ impl<T, A: Alloc> RawVec<T, A> { /// # Examples /// /// ``` - /// # #![feature(alloc, raw_vec_internals)] + /// # #![feature(raw_vec_internals)] /// # extern crate alloc; /// # use std::ptr; /// # use alloc::raw_vec::RawVec; @@ -487,20 +491,20 @@ impl<T, A: Alloc> RawVec<T, A> { /// # vector.push_all(&[1, 3, 5, 7, 9]); /// # } /// ``` - pub fn reserve(&mut self, used_cap: usize, needed_extra_cap: usize) { - match self.reserve_internal(used_cap, needed_extra_cap, Infallible, Amortized) { + pub fn reserve(&mut self, used_capacity: usize, needed_extra_capacity: usize) { + match self.reserve_internal(used_capacity, needed_extra_capacity, Infallible, Amortized) { Err(CapacityOverflow) => capacity_overflow(), Err(AllocErr) => unreachable!(), Ok(()) => { /* yay */ } } } /// Attempts to ensure that the buffer contains at least enough space to hold - /// `used_cap + needed_extra_cap` elements. If it doesn't already have + /// `used_capacity + needed_extra_capacity` elements. If it doesn't already have /// enough capacity, will reallocate in place enough space plus comfortable slack /// space to get amortized `O(1)` behavior. Will limit this behaviour /// if it would needlessly cause itself to panic. /// - /// If `used_cap` exceeds `self.cap()`, this may fail to actually allocate + /// If `used_capacity` exceeds `self.capacity()`, this may fail to actually allocate /// the requested space. This is not really unsafe, but the unsafe /// code *you* write that relies on the behavior of this function may break. /// @@ -511,7 +515,7 @@ impl<T, A: Alloc> RawVec<T, A> { /// * Panics if the requested capacity exceeds `usize::MAX` bytes. /// * Panics on 32-bit platforms if the requested capacity exceeds /// `isize::MAX` bytes. - pub fn reserve_in_place(&mut self, used_cap: usize, needed_extra_cap: usize) -> bool { + pub fn reserve_in_place(&mut self, used_capacity: usize, needed_extra_capacity: usize) -> bool { unsafe { // NOTE: we don't early branch on ZSTs here because we want this // to actually catch "asking for more than usize::MAX" in that case. @@ -520,20 +524,20 @@ impl<T, A: Alloc> RawVec<T, A> { // Don't actually need any more capacity. If the current `cap` is 0, we can't // reallocate in place. - // Wrapping in case they give a bad `used_cap` + // Wrapping in case they give a bad `used_capacity` let old_layout = match self.current_layout() { Some(layout) => layout, None => return false, }; - if self.cap().wrapping_sub(used_cap) >= needed_extra_cap { + if self.capacity().wrapping_sub(used_capacity) >= needed_extra_capacity { return false; } - let new_cap = self.amortized_new_size(used_cap, needed_extra_cap) + let new_cap = self.amortized_new_size(used_capacity, needed_extra_capacity) .unwrap_or_else(|_| capacity_overflow()); - // Here, `cap < used_cap + needed_extra_cap <= new_cap` - // (regardless of whether `self.cap - used_cap` wrapped). + // Here, `cap < used_capacity + needed_extra_capacity <= new_cap` + // (regardless of whether `self.cap - used_capacity` wrapped). // Therefore we can safely call grow_in_place. let new_layout = Layout::new::<T>().repeat(new_cap).unwrap().0; @@ -632,8 +636,8 @@ use ReserveStrategy::*; impl<T, A: Alloc> RawVec<T, A> { fn reserve_internal( &mut self, - used_cap: usize, - needed_extra_cap: usize, + used_capacity: usize, + needed_extra_capacity: usize, fallibility: Fallibility, strategy: ReserveStrategy, ) -> Result<(), CollectionAllocErr> { @@ -646,15 +650,15 @@ impl<T, A: Alloc> RawVec<T, A> { // panic. // Don't actually need any more capacity. - // Wrapping in case they gave a bad `used_cap`. - if self.cap().wrapping_sub(used_cap) >= needed_extra_cap { + // Wrapping in case they gave a bad `used_capacity`. + if self.capacity().wrapping_sub(used_capacity) >= needed_extra_capacity { return Ok(()); } // Nothing we can really do about these checks :( let new_cap = match strategy { - Exact => used_cap.checked_add(needed_extra_cap).ok_or(CapacityOverflow)?, - Amortized => self.amortized_new_size(used_cap, needed_extra_cap)?, + Exact => used_capacity.checked_add(needed_extra_capacity).ok_or(CapacityOverflow)?, + Amortized => self.amortized_new_size(used_capacity, needed_extra_capacity)?, }; let new_layout = Layout::array::<T>(new_cap).map_err(|_| CapacityOverflow)?; @@ -685,14 +689,16 @@ impl<T, A: Alloc> RawVec<T, A> { impl<T> RawVec<T, Global> { /// Converts the entire buffer into `Box<[T]>`. /// - /// While it is not *strictly* Undefined Behavior to call - /// this procedure while some of the RawVec is uninitialized, - /// it certainly makes it trivial to trigger it. - /// /// Note that this will correctly reconstitute any `cap` changes /// that may have been performed. (see description of type for details) + /// + /// # Undefined Behavior + /// + /// All elements of `RawVec<T, Global>` must be initialized. Notice that + /// the rules around uninitialized boxed values are not finalized yet, + /// but until they are, it is advisable to avoid them. pub unsafe fn into_box(self) -> Box<[T]> { - // NOTE: not calling `cap()` here, actually using the real `cap` field! + // NOTE: not calling `capacity()` here, actually using the real `cap` field! let slice = slice::from_raw_parts_mut(self.ptr(), self.cap); let output: Box<[T]> = Box::from_raw(slice); mem::forget(self); @@ -745,82 +751,3 @@ fn alloc_guard(alloc_size: usize) -> Result<(), CollectionAllocErr> { fn capacity_overflow() -> ! { panic!("capacity overflow") } - -#[cfg(test)] -mod tests { - use super::*; - - #[test] - fn allocator_param() { - use crate::alloc::AllocErr; - - // Writing a test of integration between third-party - // allocators and RawVec is a little tricky because the RawVec - // API does not expose fallible allocation methods, so we - // cannot check what happens when allocator is exhausted - // (beyond detecting a panic). - // - // Instead, this just checks that the RawVec methods do at - // least go through the Allocator API when it reserves - // storage. - - // A dumb allocator that consumes a fixed amount of fuel - // before allocation attempts start failing. - struct BoundedAlloc { fuel: usize } - unsafe impl Alloc for BoundedAlloc { - unsafe fn alloc(&mut self, layout: Layout) -> Result<NonNull<u8>, AllocErr> { - let size = layout.size(); - if size > self.fuel { - return Err(AllocErr); - } - match Global.alloc(layout) { - ok @ Ok(_) => { self.fuel -= size; ok } - err @ Err(_) => err, - } - } - unsafe fn dealloc(&mut self, ptr: NonNull<u8>, layout: Layout) { - Global.dealloc(ptr, layout) - } - } - - let a = BoundedAlloc { fuel: 500 }; - let mut v: RawVec<u8, _> = RawVec::with_capacity_in(50, a); - assert_eq!(v.a.fuel, 450); - v.reserve(50, 150); // (causes a realloc, thus using 50 + 150 = 200 units of fuel) - assert_eq!(v.a.fuel, 250); - } - - #[test] - fn reserve_does_not_overallocate() { - { - let mut v: RawVec<u32> = RawVec::new(); - // First `reserve` allocates like `reserve_exact` - v.reserve(0, 9); - assert_eq!(9, v.cap()); - } - - { - let mut v: RawVec<u32> = RawVec::new(); - v.reserve(0, 7); - assert_eq!(7, v.cap()); - // 97 if more than double of 7, so `reserve` should work - // like `reserve_exact`. - v.reserve(7, 90); - assert_eq!(97, v.cap()); - } - - { - let mut v: RawVec<u32> = RawVec::new(); - v.reserve(0, 12); - assert_eq!(12, v.cap()); - v.reserve(12, 3); - // 3 is less than half of 12, so `reserve` must grow - // exponentially. At the time of writing this test grow - // factor is 2, so new capacity is 24, however, grow factor - // of 1.5 is OK too. Hence `>= 18` in assert. - assert!(v.cap() >= 12 + 12 / 2); - } - } - - -} diff --git a/src/liballoc/raw_vec/tests.rs b/src/liballoc/raw_vec/tests.rs new file mode 100644 index 00000000000..c389898d1ef --- /dev/null +++ b/src/liballoc/raw_vec/tests.rs @@ -0,0 +1,73 @@ +use super::*; + +#[test] +fn allocator_param() { + use crate::alloc::AllocErr; + + // Writing a test of integration between third-party + // allocators and RawVec is a little tricky because the RawVec + // API does not expose fallible allocation methods, so we + // cannot check what happens when allocator is exhausted + // (beyond detecting a panic). + // + // Instead, this just checks that the RawVec methods do at + // least go through the Allocator API when it reserves + // storage. + + // A dumb allocator that consumes a fixed amount of fuel + // before allocation attempts start failing. + struct BoundedAlloc { fuel: usize } + unsafe impl Alloc for BoundedAlloc { + unsafe fn alloc(&mut self, layout: Layout) -> Result<NonNull<u8>, AllocErr> { + let size = layout.size(); + if size > self.fuel { + return Err(AllocErr); + } + match Global.alloc(layout) { + ok @ Ok(_) => { self.fuel -= size; ok } + err @ Err(_) => err, + } + } + unsafe fn dealloc(&mut self, ptr: NonNull<u8>, layout: Layout) { + Global.dealloc(ptr, layout) + } + } + + let a = BoundedAlloc { fuel: 500 }; + let mut v: RawVec<u8, _> = RawVec::with_capacity_in(50, a); + assert_eq!(v.a.fuel, 450); + v.reserve(50, 150); // (causes a realloc, thus using 50 + 150 = 200 units of fuel) + assert_eq!(v.a.fuel, 250); +} + +#[test] +fn reserve_does_not_overallocate() { + { + let mut v: RawVec<u32> = RawVec::new(); + // First `reserve` allocates like `reserve_exact` + v.reserve(0, 9); + assert_eq!(9, v.capacity()); + } + + { + let mut v: RawVec<u32> = RawVec::new(); + v.reserve(0, 7); + assert_eq!(7, v.capacity()); + // 97 if more than double of 7, so `reserve` should work + // like `reserve_exact`. + v.reserve(7, 90); + assert_eq!(97, v.capacity()); + } + + { + let mut v: RawVec<u32> = RawVec::new(); + v.reserve(0, 12); + assert_eq!(12, v.capacity()); + v.reserve(12, 3); + // 3 is less than half of 12, so `reserve` must grow + // exponentially. At the time of writing this test grow + // factor is 2, so new capacity is 24, however, grow factor + // of 1.5 is OK too. Hence `>= 18` in assert. + assert!(v.capacity() >= 12 + 12 / 2); + } +} diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs index 68eecd97ea1..0c406a92029 100644 --- a/src/liballoc/rc.rs +++ b/src/liballoc/rc.rs @@ -232,25 +232,30 @@ use crate::boxed::Box; use std::boxed::Box; use core::any::Any; +use core::array::LengthAtMost32; use core::borrow; use core::cell::Cell; use core::cmp::Ordering; use core::fmt; use core::hash::{Hash, Hasher}; use core::intrinsics::abort; +use core::iter; use core::marker::{self, Unpin, Unsize, PhantomData}; -use core::mem::{self, align_of_val, forget, size_of_val}; +use core::mem::{self, align_of, align_of_val, forget, size_of_val}; use core::ops::{Deref, Receiver, CoerceUnsized, DispatchFromDyn}; use core::pin::Pin; use core::ptr::{self, NonNull}; -use core::slice::from_raw_parts_mut; -use core::convert::From; +use core::slice::{self, from_raw_parts_mut}; +use core::convert::{From, TryFrom}; use core::usize; use crate::alloc::{Global, Alloc, Layout, box_free, handle_alloc_error}; use crate::string::String; use crate::vec::Vec; +#[cfg(test)] +mod tests; + struct RcBox<T: ?Sized> { strong: Cell<usize>, weak: Cell<usize>, @@ -286,6 +291,19 @@ impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Rc<U>> for Rc<T> {} #[unstable(feature = "dispatch_from_dyn", issue = "0")] impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Rc<U>> for Rc<T> {} +impl<T: ?Sized> Rc<T> { + fn from_inner(ptr: NonNull<RcBox<T>>) -> Self { + Self { + ptr, + phantom: PhantomData, + } + } + + unsafe fn from_ptr(ptr: *mut RcBox<T>) -> Self { + Self::from_inner(NonNull::new_unchecked(ptr)) + } +} + impl<T> Rc<T> { /// Constructs a new `Rc<T>`. /// @@ -298,18 +316,15 @@ impl<T> Rc<T> { /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn new(value: T) -> Rc<T> { - Rc { - // there is an implicit weak pointer owned by all the strong - // pointers, which ensures that the weak destructor never frees - // the allocation while the strong destructor is running, even - // if the weak pointer is stored inside the strong one. - ptr: Box::into_raw_non_null(box RcBox { - strong: Cell::new(1), - weak: Cell::new(1), - value, - }), - phantom: PhantomData, - } + // There is an implicit weak pointer owned by all the strong + // pointers, which ensures that the weak destructor never frees + // the allocation while the strong destructor is running, even + // if the weak pointer is stored inside the strong one. + Self::from_inner(Box::into_raw_non_null(box RcBox { + strong: Cell::new(1), + weak: Cell::new(1), + value, + })) } /// Constructs a new `Pin<Rc<T>>`. If `T` does not implement `Unpin`, then @@ -375,9 +390,9 @@ impl<T: ?Sized> Rc<T> { /// ``` /// use std::rc::Rc; /// - /// let x = Rc::new(10); + /// let x = Rc::new("hello".to_owned()); /// let x_ptr = Rc::into_raw(x); - /// assert_eq!(unsafe { *x_ptr }, 10); + /// assert_eq!(unsafe { &*x_ptr }, "hello"); /// ``` #[stable(feature = "rc_raw", since = "1.17.0")] pub fn into_raw(this: Self) -> *const T { @@ -401,13 +416,13 @@ impl<T: ?Sized> Rc<T> { /// ``` /// use std::rc::Rc; /// - /// let x = Rc::new(10); + /// let x = Rc::new("hello".to_owned()); /// let x_ptr = Rc::into_raw(x); /// /// unsafe { /// // Convert back to an `Rc` to prevent leak. /// let x = Rc::from_raw(x_ptr); - /// assert_eq!(*x, 10); + /// assert_eq!(&*x, "hello"); /// /// // Further calls to `Rc::from_raw(x_ptr)` would be memory unsafe. /// } @@ -416,20 +431,13 @@ impl<T: ?Sized> Rc<T> { /// ``` #[stable(feature = "rc_raw", since = "1.17.0")] pub unsafe fn from_raw(ptr: *const T) -> Self { - // Align the unsized value to the end of the RcBox. - // Because it is ?Sized, it will always be the last field in memory. - let align = align_of_val(&*ptr); - let layout = Layout::new::<RcBox<()>>(); - let offset = (layout.size() + layout.padding_needed_for(align)) as isize; + let offset = data_offset(ptr); // Reverse the offset to find the original RcBox. let fake_ptr = ptr as *mut RcBox<T>; let rc_ptr = set_data_ptr(fake_ptr, (ptr as *mut u8).offset(-offset)); - Rc { - ptr: NonNull::new_unchecked(rc_ptr), - phantom: PhantomData, - } + Self::from_ptr(rc_ptr) } /// Consumes the `Rc`, returning the wrapped pointer as `NonNull<T>`. @@ -441,10 +449,10 @@ impl<T: ?Sized> Rc<T> { /// /// use std::rc::Rc; /// - /// let x = Rc::new(10); + /// let x = Rc::new("hello".to_owned()); /// let ptr = Rc::into_raw_non_null(x); - /// let deref = unsafe { *ptr.as_ref() }; - /// assert_eq!(deref, 10); + /// let deref = unsafe { ptr.as_ref() }; + /// assert_eq!(deref, "hello"); /// ``` #[unstable(feature = "rc_into_raw_non_null", issue = "47336")] #[inline] @@ -584,15 +592,18 @@ impl<T: ?Sized> Rc<T> { impl<T: Clone> Rc<T> { /// Makes a mutable reference into the given `Rc`. /// - /// If there are other `Rc` or [`Weak`][weak] pointers to the same value, - /// then `make_mut` will invoke [`clone`][clone] on the inner value to - /// ensure unique ownership. This is also referred to as clone-on-write. + /// If there are other `Rc` pointers to the same value, then `make_mut` will + /// [`clone`] the inner value to ensure unique ownership. This is also + /// referred to as clone-on-write. /// - /// See also [`get_mut`][get_mut], which will fail rather than cloning. + /// If there are no other `Rc` pointers to this value, then [`Weak`] + /// pointers to this value will be dissassociated. /// - /// [weak]: struct.Weak.html - /// [clone]: ../../std/clone/trait.Clone.html#tymethod.clone - /// [get_mut]: struct.Rc.html#method.get_mut + /// See also [`get_mut`], which will fail rather than cloning. + /// + /// [`Weak`]: struct.Weak.html + /// [`clone`]: ../../std/clone/trait.Clone.html#tymethod.clone + /// [`get_mut`]: struct.Rc.html#method.get_mut /// /// # Examples /// @@ -611,6 +622,23 @@ impl<T: Clone> Rc<T> { /// assert_eq!(*data, 8); /// assert_eq!(*other_data, 12); /// ``` + /// + /// [`Weak`] pointers will be dissassociated: + /// + /// ``` + /// use std::rc::Rc; + /// + /// let mut data = Rc::new(75); + /// let weak = Rc::downgrade(&data); + /// + /// assert!(75 == *data); + /// assert!(75 == *weak.upgrade().unwrap()); + /// + /// *Rc::make_mut(&mut data) += 1; + /// + /// assert!(76 == *data); + /// assert!(weak.upgrade().is_none()); + /// ``` #[inline] #[stable(feature = "rc_unique", since = "1.4.0")] pub fn make_mut(this: &mut Self) -> &mut T { @@ -667,7 +695,7 @@ impl Rc<dyn Any> { if (*self).is::<T>() { let ptr = self.ptr.cast::<RcBox<T>>(); forget(self); - Ok(Rc { ptr, phantom: PhantomData }) + Ok(Rc::from_inner(ptr)) } else { Err(self) } @@ -675,21 +703,29 @@ impl Rc<dyn Any> { } impl<T: ?Sized> Rc<T> { - // Allocates an `RcBox<T>` with sufficient space for an unsized value - unsafe fn allocate_for_ptr(ptr: *const T) -> *mut RcBox<T> { - // Calculate layout using the given value. + /// Allocates an `RcBox<T>` with sufficient space for + /// an unsized value where the value has the layout provided. + /// + /// The function `mem_to_rcbox` is called with the data pointer + /// and must return back a (potentially fat)-pointer for the `RcBox<T>`. + unsafe fn allocate_for_unsized( + value_layout: Layout, + mem_to_rcbox: impl FnOnce(*mut u8) -> *mut RcBox<T> + ) -> *mut RcBox<T> { + // Calculate layout using the given value layout. // Previously, layout was calculated on the expression // `&*(ptr as *const RcBox<T>)`, but this created a misaligned // reference (see #54908). let layout = Layout::new::<RcBox<()>>() - .extend(Layout::for_value(&*ptr)).unwrap().0 + .extend(value_layout).unwrap().0 .pad_to_align().unwrap(); + // Allocate for the layout. let mem = Global.alloc(layout) .unwrap_or_else(|_| handle_alloc_error(layout)); // Initialize the RcBox - let inner = set_data_ptr(ptr as *mut T, mem.as_ptr() as *mut u8) as *mut RcBox<T>; + let inner = mem_to_rcbox(mem.as_ptr()); debug_assert_eq!(Layout::for_value(&*inner), layout); ptr::write(&mut (*inner).strong, Cell::new(1)); @@ -698,6 +734,15 @@ impl<T: ?Sized> Rc<T> { inner } + /// Allocates an `RcBox<T>` with sufficient space for an unsized value + unsafe fn allocate_for_ptr(ptr: *const T) -> *mut RcBox<T> { + // Allocate for the `RcBox<T>` using the given value. + Self::allocate_for_unsized( + Layout::for_value(&*ptr), + |mem| set_data_ptr(ptr as *mut T, mem) as *mut RcBox<T>, + ) + } + fn from_box(v: Box<T>) -> Rc<T> { unsafe { let box_unique = Box::into_unique(v); @@ -715,44 +760,49 @@ impl<T: ?Sized> Rc<T> { // Free the allocation without dropping its contents box_free(box_unique); - Rc { ptr: NonNull::new_unchecked(ptr), phantom: PhantomData } + Self::from_ptr(ptr) } } } -// Sets the data pointer of a `?Sized` raw pointer. -// -// For a slice/trait object, this sets the `data` field and leaves the rest -// unchanged. For a sized raw pointer, this simply sets the pointer. +impl<T> Rc<[T]> { + /// Allocates an `RcBox<[T]>` with the given length. + unsafe fn allocate_for_slice(len: usize) -> *mut RcBox<[T]> { + Self::allocate_for_unsized( + Layout::array::<T>(len).unwrap(), + |mem| ptr::slice_from_raw_parts_mut(mem as *mut T, len) as *mut RcBox<[T]>, + ) + } +} + +/// Sets the data pointer of a `?Sized` raw pointer. +/// +/// For a slice/trait object, this sets the `data` field and leaves the rest +/// unchanged. For a sized raw pointer, this simply sets the pointer. unsafe fn set_data_ptr<T: ?Sized, U>(mut ptr: *mut T, data: *mut U) -> *mut T { ptr::write(&mut ptr as *mut _ as *mut *mut u8, data as *mut u8); ptr } impl<T> Rc<[T]> { - // Copy elements from slice into newly allocated Rc<[T]> - // - // Unsafe because the caller must either take ownership or bind `T: Copy` + /// Copy elements from slice into newly allocated Rc<[T]> + /// + /// Unsafe because the caller must either take ownership or bind `T: Copy` unsafe fn copy_from_slice(v: &[T]) -> Rc<[T]> { - let v_ptr = v as *const [T]; - let ptr = Self::allocate_for_ptr(v_ptr); + let ptr = Self::allocate_for_slice(v.len()); ptr::copy_nonoverlapping( v.as_ptr(), &mut (*ptr).value as *mut [T] as *mut T, v.len()); - Rc { ptr: NonNull::new_unchecked(ptr), phantom: PhantomData } + Self::from_ptr(ptr) } -} - -trait RcFromSlice<T> { - fn from_slice(slice: &[T]) -> Self; -} -impl<T: Clone> RcFromSlice<T> for Rc<[T]> { - #[inline] - default fn from_slice(v: &[T]) -> Self { + /// Constructs an `Rc<[T]>` from an iterator known to be of a certain size. + /// + /// Behavior is undefined should the size be wrong. + unsafe fn from_iter_exact(iter: impl iter::Iterator<Item = T>, len: usize) -> Rc<[T]> { // Panic guard while cloning T elements. // In the event of a panic, elements that have been written // into the new RcBox will be dropped, then the memory freed. @@ -769,37 +819,48 @@ impl<T: Clone> RcFromSlice<T> for Rc<[T]> { let slice = from_raw_parts_mut(self.elems, self.n_elems); ptr::drop_in_place(slice); - Global.dealloc(self.mem, self.layout.clone()); + Global.dealloc(self.mem, self.layout); } } } - unsafe { - let v_ptr = v as *const [T]; - let ptr = Self::allocate_for_ptr(v_ptr); + let ptr = Self::allocate_for_slice(len); - let mem = ptr as *mut _ as *mut u8; - let layout = Layout::for_value(&*ptr); + let mem = ptr as *mut _ as *mut u8; + let layout = Layout::for_value(&*ptr); - // Pointer to first element - let elems = &mut (*ptr).value as *mut [T] as *mut T; + // Pointer to first element + let elems = &mut (*ptr).value as *mut [T] as *mut T; - let mut guard = Guard{ - mem: NonNull::new_unchecked(mem), - elems: elems, - layout: layout, - n_elems: 0, - }; + let mut guard = Guard { + mem: NonNull::new_unchecked(mem), + elems, + layout, + n_elems: 0, + }; - for (i, item) in v.iter().enumerate() { - ptr::write(elems.add(i), item.clone()); - guard.n_elems += 1; - } + for (i, item) in iter.enumerate() { + ptr::write(elems.add(i), item); + guard.n_elems += 1; + } - // All clear. Forget the guard so it doesn't free the new RcBox. - forget(guard); + // All clear. Forget the guard so it doesn't free the new RcBox. + forget(guard); - Rc { ptr: NonNull::new_unchecked(ptr), phantom: PhantomData } + Self::from_ptr(ptr) + } +} + +/// Specialization trait used for `From<&[T]>`. +trait RcFromSlice<T> { + fn from_slice(slice: &[T]) -> Self; +} + +impl<T: Clone> RcFromSlice<T> for Rc<[T]> { + #[inline] + default fn from_slice(v: &[T]) -> Self { + unsafe { + Self::from_iter_exact(v.iter().cloned(), v.len()) } } } @@ -891,7 +952,7 @@ impl<T: ?Sized> Clone for Rc<T> { #[inline] fn clone(&self) -> Rc<T> { self.inc_strong(); - Rc { ptr: self.ptr, phantom: PhantomData } + Self::from_inner(self.ptr) } } @@ -932,6 +993,11 @@ impl<T: ?Sized + PartialEq> RcEqIdent<T> for Rc<T> { } } +/// We're doing this specialization here, and not as a more general optimization on `&T`, because it +/// would otherwise add a cost to all equality checks on refs. We assume that `Rc`s are used to +/// store large values, that are slow to clone, but also heavy to check for equality, causing this +/// cost to pay off more easily. It's also more likely to have two `Rc` clones, that point to +/// the same value, than two `&T`s. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized + Eq> RcEqIdent<T> for Rc<T> { #[inline] @@ -1192,6 +1258,114 @@ impl<T> From<Vec<T>> for Rc<[T]> { } } +#[unstable(feature = "boxed_slice_try_from", issue = "0")] +impl<T, const N: usize> TryFrom<Rc<[T]>> for Rc<[T; N]> +where + [T; N]: LengthAtMost32, +{ + type Error = Rc<[T]>; + + fn try_from(boxed_slice: Rc<[T]>) -> Result<Self, Self::Error> { + if boxed_slice.len() == N { + Ok(unsafe { Rc::from_raw(Rc::into_raw(boxed_slice) as *mut [T; N]) }) + } else { + Err(boxed_slice) + } + } +} + +#[stable(feature = "shared_from_iter", since = "1.37.0")] +impl<T> iter::FromIterator<T> for Rc<[T]> { + /// Takes each element in the `Iterator` and collects it into an `Rc<[T]>`. + /// + /// # Performance characteristics + /// + /// ## The general case + /// + /// In the general case, collecting into `Rc<[T]>` is done by first + /// collecting into a `Vec<T>`. That is, when writing the following: + /// + /// ```rust + /// # use std::rc::Rc; + /// let evens: Rc<[u8]> = (0..10).filter(|&x| x % 2 == 0).collect(); + /// # assert_eq!(&*evens, &[0, 2, 4, 6, 8]); + /// ``` + /// + /// this behaves as if we wrote: + /// + /// ```rust + /// # use std::rc::Rc; + /// let evens: Rc<[u8]> = (0..10).filter(|&x| x % 2 == 0) + /// .collect::<Vec<_>>() // The first set of allocations happens here. + /// .into(); // A second allocation for `Rc<[T]>` happens here. + /// # assert_eq!(&*evens, &[0, 2, 4, 6, 8]); + /// ``` + /// + /// This will allocate as many times as needed for constructing the `Vec<T>` + /// and then it will allocate once for turning the `Vec<T>` into the `Rc<[T]>`. + /// + /// ## Iterators of known length + /// + /// When your `Iterator` implements `TrustedLen` and is of an exact size, + /// a single allocation will be made for the `Rc<[T]>`. For example: + /// + /// ```rust + /// # use std::rc::Rc; + /// let evens: Rc<[u8]> = (0..10).collect(); // Just a single allocation happens here. + /// # assert_eq!(&*evens, &*(0..10).collect::<Vec<_>>()); + /// ``` + fn from_iter<I: iter::IntoIterator<Item = T>>(iter: I) -> Self { + RcFromIter::from_iter(iter.into_iter()) + } +} + +/// Specialization trait used for collecting into `Rc<[T]>`. +trait RcFromIter<T, I> { + fn from_iter(iter: I) -> Self; +} + +impl<T, I: Iterator<Item = T>> RcFromIter<T, I> for Rc<[T]> { + default fn from_iter(iter: I) -> Self { + iter.collect::<Vec<T>>().into() + } +} + +impl<T, I: iter::TrustedLen<Item = T>> RcFromIter<T, I> for Rc<[T]> { + default fn from_iter(iter: I) -> Self { + // This is the case for a `TrustedLen` iterator. + let (low, high) = iter.size_hint(); + if let Some(high) = high { + debug_assert_eq!( + low, high, + "TrustedLen iterator's size hint is not exact: {:?}", + (low, high) + ); + + unsafe { + // SAFETY: We need to ensure that the iterator has an exact length and we have. + Rc::from_iter_exact(iter, low) + } + } else { + // Fall back to normal implementation. + iter.collect::<Vec<T>>().into() + } + } +} + +impl<'a, T: 'a + Clone> RcFromIter<&'a T, slice::Iter<'a, T>> for Rc<[T]> { + fn from_iter(iter: slice::Iter<'a, T>) -> Self { + // Delegate to `impl<T: Clone> From<&[T]> for Rc<[T]>`. + // + // In the case that `T: Copy`, we get to use `ptr::copy_nonoverlapping` + // which is even more performant. + // + // In the fall-back case we have `T: Clone`. This is still better + // than the `TrustedLen` implementation as slices have a known length + // and so we get to avoid calling `size_hint` and avoid the branching. + iter.as_slice().into() + } +} + /// `Weak` is a version of [`Rc`] that holds a non-owning reference to the /// managed value. The value is accessed by calling [`upgrade`] on the `Weak` /// pointer, which returns an [`Option`]`<`[`Rc`]`<T>>`. @@ -1257,6 +1431,143 @@ impl<T> Weak<T> { ptr: NonNull::new(usize::MAX as *mut RcBox<T>).expect("MAX is not 0"), } } + + /// Returns a raw pointer to the object `T` pointed to by this `Weak<T>`. + /// + /// It is up to the caller to ensure that the object is still alive when accessing it through + /// the pointer. + /// + /// The pointer may be [`null`] or be dangling in case the object has already been destroyed. + /// + /// # Examples + /// + /// ``` + /// #![feature(weak_into_raw)] + /// + /// use std::rc::Rc; + /// use std::ptr; + /// + /// let strong = Rc::new("hello".to_owned()); + /// let weak = Rc::downgrade(&strong); + /// // Both point to the same object + /// assert!(ptr::eq(&*strong, weak.as_raw())); + /// // The strong here keeps it alive, so we can still access the object. + /// assert_eq!("hello", unsafe { &*weak.as_raw() }); + /// + /// drop(strong); + /// // But not any more. We can do weak.as_raw(), but accessing the pointer would lead to + /// // undefined behaviour. + /// // assert_eq!("hello", unsafe { &*weak.as_raw() }); + /// ``` + /// + /// [`null`]: ../../std/ptr/fn.null.html + #[unstable(feature = "weak_into_raw", issue = "60728")] + pub fn as_raw(&self) -> *const T { + match self.inner() { + None => ptr::null(), + Some(inner) => { + let offset = data_offset_sized::<T>(); + let ptr = inner as *const RcBox<T>; + // Note: while the pointer we create may already point to dropped value, the + // allocation still lives (it must hold the weak point as long as we are alive). + // Therefore, the offset is OK to do, it won't get out of the allocation. + let ptr = unsafe { (ptr as *const u8).offset(offset) }; + ptr as *const T + } + } + } + + /// Consumes the `Weak<T>` and turns it into a raw pointer. + /// + /// This converts the weak pointer into a raw pointer, preserving the original weak count. It + /// can be turned back into the `Weak<T>` with [`from_raw`]. + /// + /// The same restrictions of accessing the target of the pointer as with + /// [`as_raw`] apply. + /// + /// # Examples + /// + /// ``` + /// #![feature(weak_into_raw)] + /// + /// use std::rc::{Rc, Weak}; + /// + /// let strong = Rc::new("hello".to_owned()); + /// let weak = Rc::downgrade(&strong); + /// let raw = weak.into_raw(); + /// + /// assert_eq!(1, Rc::weak_count(&strong)); + /// assert_eq!("hello", unsafe { &*raw }); + /// + /// drop(unsafe { Weak::from_raw(raw) }); + /// assert_eq!(0, Rc::weak_count(&strong)); + /// ``` + /// + /// [`from_raw`]: struct.Weak.html#method.from_raw + /// [`as_raw`]: struct.Weak.html#method.as_raw + #[unstable(feature = "weak_into_raw", issue = "60728")] + pub fn into_raw(self) -> *const T { + let result = self.as_raw(); + mem::forget(self); + result + } + + /// Converts a raw pointer previously created by [`into_raw`] back into `Weak<T>`. + /// + /// This can be used to safely get a strong reference (by calling [`upgrade`] + /// later) or to deallocate the weak count by dropping the `Weak<T>`. + /// + /// It takes ownership of one weak count. In case a [`null`] is passed, a dangling [`Weak`] is + /// returned. + /// + /// # Safety + /// + /// The pointer must represent one valid weak count. In other words, it must point to `T` which + /// is or *was* managed by an [`Rc`] and the weak count of that [`Rc`] must not have reached + /// 0. It is allowed for the strong count to be 0. + /// + /// # Examples + /// + /// ``` + /// #![feature(weak_into_raw)] + /// + /// use std::rc::{Rc, Weak}; + /// + /// let strong = Rc::new("hello".to_owned()); + /// + /// let raw_1 = Rc::downgrade(&strong).into_raw(); + /// let raw_2 = Rc::downgrade(&strong).into_raw(); + /// + /// assert_eq!(2, Rc::weak_count(&strong)); + /// + /// assert_eq!("hello", &*unsafe { Weak::from_raw(raw_1) }.upgrade().unwrap()); + /// assert_eq!(1, Rc::weak_count(&strong)); + /// + /// drop(strong); + /// + /// // Decrement the last weak count. + /// assert!(unsafe { Weak::from_raw(raw_2) }.upgrade().is_none()); + /// ``` + /// + /// [`null`]: ../../std/ptr/fn.null.html + /// [`into_raw`]: struct.Weak.html#method.into_raw + /// [`upgrade`]: struct.Weak.html#method.upgrade + /// [`Rc`]: struct.Rc.html + /// [`Weak`]: struct.Weak.html + #[unstable(feature = "weak_into_raw", issue = "60728")] + pub unsafe fn from_raw(ptr: *const T) -> Self { + if ptr.is_null() { + Self::new() + } else { + // See Rc::from_raw for details + let offset = data_offset(ptr); + let fake_ptr = ptr as *mut RcBox<T>; + let ptr = set_data_ptr(fake_ptr, (ptr as *mut u8).offset(-offset)); + Weak { + ptr: NonNull::new(ptr).expect("Invalid pointer passed to from_raw"), + } + } + } } pub(crate) fn is_dangling<T: ?Sized>(ptr: NonNull<T>) -> bool { @@ -1298,7 +1609,7 @@ impl<T: ?Sized> Weak<T> { None } else { inner.inc_strong(); - Some(Rc { ptr: self.ptr, phantom: PhantomData }) + Some(Rc::from_inner(self.ptr)) } } @@ -1357,18 +1668,18 @@ impl<T: ?Sized> Weak<T> { /// /// ``` /// #![feature(weak_ptr_eq)] - /// use std::rc::{Rc, Weak}; + /// use std::rc::Rc; /// /// let first_rc = Rc::new(5); /// let first = Rc::downgrade(&first_rc); /// let second = Rc::downgrade(&first_rc); /// - /// assert!(Weak::ptr_eq(&first, &second)); + /// assert!(first.ptr_eq(&second)); /// /// let third_rc = Rc::new(5); /// let third = Rc::downgrade(&third_rc); /// - /// assert!(!Weak::ptr_eq(&first, &third)); + /// assert!(!first.ptr_eq(&third)); /// ``` /// /// Comparing `Weak::new`. @@ -1379,16 +1690,16 @@ impl<T: ?Sized> Weak<T> { /// /// let first = Weak::new(); /// let second = Weak::new(); - /// assert!(Weak::ptr_eq(&first, &second)); + /// assert!(first.ptr_eq(&second)); /// /// let third_rc = Rc::new(()); /// let third = Rc::downgrade(&third_rc); - /// assert!(!Weak::ptr_eq(&first, &third)); + /// assert!(!first.ptr_eq(&third)); /// ``` #[inline] #[unstable(feature = "weak_ptr_eq", issue = "55981")] - pub fn ptr_eq(this: &Self, other: &Self) -> bool { - this.ptr.as_ptr() == other.ptr.as_ptr() + pub fn ptr_eq(&self, other: &Self) -> bool { + self.ptr.as_ptr() == other.ptr.as_ptr() } } @@ -1502,14 +1813,16 @@ trait RcBoxPtr<T: ?Sized> { #[inline] fn inc_strong(&self) { + let strong = self.strong(); + // We want to abort on overflow instead of dropping the value. // The reference count will never be zero when this is called; // nevertheless, we insert an abort here to hint LLVM at // an otherwise missed optimization. - if self.strong() == 0 || self.strong() == usize::max_value() { + if strong == 0 || strong == usize::max_value() { unsafe { abort(); } } - self.inner().strong.set(self.strong() + 1); + self.inner().strong.set(strong + 1); } #[inline] @@ -1524,14 +1837,16 @@ trait RcBoxPtr<T: ?Sized> { #[inline] fn inc_weak(&self) { + let weak = self.weak(); + // We want to abort on overflow instead of dropping the value. // The reference count will never be zero when this is called; // nevertheless, we insert an abort here to hint LLVM at // an otherwise missed optimization. - if self.weak() == 0 || self.weak() == usize::max_value() { + if weak == 0 || weak == usize::max_value() { unsafe { abort(); } } - self.inner().weak.set(self.weak() + 1); + self.inner().weak.set(weak + 1); } #[inline] @@ -1556,436 +1871,6 @@ impl<T: ?Sized> RcBoxPtr<T> for RcBox<T> { } } -#[cfg(test)] -mod tests { - use super::{Rc, Weak}; - use std::boxed::Box; - use std::cell::RefCell; - use std::option::Option::{self, None, Some}; - use std::result::Result::{Err, Ok}; - use std::mem::drop; - use std::clone::Clone; - use std::convert::From; - - #[test] - fn test_clone() { - let x = Rc::new(RefCell::new(5)); - let y = x.clone(); - *x.borrow_mut() = 20; - assert_eq!(*y.borrow(), 20); - } - - #[test] - fn test_simple() { - let x = Rc::new(5); - assert_eq!(*x, 5); - } - - #[test] - fn test_simple_clone() { - let x = Rc::new(5); - let y = x.clone(); - assert_eq!(*x, 5); - assert_eq!(*y, 5); - } - - #[test] - fn test_destructor() { - let x: Rc<Box<_>> = Rc::new(box 5); - assert_eq!(**x, 5); - } - - #[test] - fn test_live() { - let x = Rc::new(5); - let y = Rc::downgrade(&x); - assert!(y.upgrade().is_some()); - } - - #[test] - fn test_dead() { - let x = Rc::new(5); - let y = Rc::downgrade(&x); - drop(x); - assert!(y.upgrade().is_none()); - } - - #[test] - fn weak_self_cyclic() { - struct Cycle { - x: RefCell<Option<Weak<Cycle>>>, - } - - let a = Rc::new(Cycle { x: RefCell::new(None) }); - let b = Rc::downgrade(&a.clone()); - *a.x.borrow_mut() = Some(b); - - // hopefully we don't double-free (or leak)... - } - - #[test] - fn is_unique() { - let x = Rc::new(3); - assert!(Rc::is_unique(&x)); - let y = x.clone(); - assert!(!Rc::is_unique(&x)); - drop(y); - assert!(Rc::is_unique(&x)); - let w = Rc::downgrade(&x); - assert!(!Rc::is_unique(&x)); - drop(w); - assert!(Rc::is_unique(&x)); - } - - #[test] - fn test_strong_count() { - let a = Rc::new(0); - assert!(Rc::strong_count(&a) == 1); - let w = Rc::downgrade(&a); - assert!(Rc::strong_count(&a) == 1); - let b = w.upgrade().expect("upgrade of live rc failed"); - assert!(Rc::strong_count(&b) == 2); - assert!(Rc::strong_count(&a) == 2); - drop(w); - drop(a); - assert!(Rc::strong_count(&b) == 1); - let c = b.clone(); - assert!(Rc::strong_count(&b) == 2); - assert!(Rc::strong_count(&c) == 2); - } - - #[test] - fn test_weak_count() { - let a = Rc::new(0); - assert!(Rc::strong_count(&a) == 1); - assert!(Rc::weak_count(&a) == 0); - let w = Rc::downgrade(&a); - assert!(Rc::strong_count(&a) == 1); - assert!(Rc::weak_count(&a) == 1); - drop(w); - assert!(Rc::strong_count(&a) == 1); - assert!(Rc::weak_count(&a) == 0); - let c = a.clone(); - assert!(Rc::strong_count(&a) == 2); - assert!(Rc::weak_count(&a) == 0); - drop(c); - } - - #[test] - fn weak_counts() { - assert_eq!(Weak::weak_count(&Weak::<u64>::new()), None); - assert_eq!(Weak::strong_count(&Weak::<u64>::new()), 0); - - let a = Rc::new(0); - let w = Rc::downgrade(&a); - assert_eq!(Weak::strong_count(&w), 1); - assert_eq!(Weak::weak_count(&w), Some(1)); - let w2 = w.clone(); - assert_eq!(Weak::strong_count(&w), 1); - assert_eq!(Weak::weak_count(&w), Some(2)); - assert_eq!(Weak::strong_count(&w2), 1); - assert_eq!(Weak::weak_count(&w2), Some(2)); - drop(w); - assert_eq!(Weak::strong_count(&w2), 1); - assert_eq!(Weak::weak_count(&w2), Some(1)); - let a2 = a.clone(); - assert_eq!(Weak::strong_count(&w2), 2); - assert_eq!(Weak::weak_count(&w2), Some(1)); - drop(a2); - drop(a); - assert_eq!(Weak::strong_count(&w2), 0); - assert_eq!(Weak::weak_count(&w2), Some(1)); - drop(w2); - } - - #[test] - fn try_unwrap() { - let x = Rc::new(3); - assert_eq!(Rc::try_unwrap(x), Ok(3)); - let x = Rc::new(4); - let _y = x.clone(); - assert_eq!(Rc::try_unwrap(x), Err(Rc::new(4))); - let x = Rc::new(5); - let _w = Rc::downgrade(&x); - assert_eq!(Rc::try_unwrap(x), Ok(5)); - } - - #[test] - fn into_from_raw() { - let x = Rc::new(box "hello"); - let y = x.clone(); - - let x_ptr = Rc::into_raw(x); - drop(y); - unsafe { - assert_eq!(**x_ptr, "hello"); - - let x = Rc::from_raw(x_ptr); - assert_eq!(**x, "hello"); - - assert_eq!(Rc::try_unwrap(x).map(|x| *x), Ok("hello")); - } - } - - #[test] - fn test_into_from_raw_unsized() { - use std::fmt::Display; - use std::string::ToString; - - let rc: Rc<str> = Rc::from("foo"); - - let ptr = Rc::into_raw(rc.clone()); - let rc2 = unsafe { Rc::from_raw(ptr) }; - - assert_eq!(unsafe { &*ptr }, "foo"); - assert_eq!(rc, rc2); - - let rc: Rc<dyn Display> = Rc::new(123); - - let ptr = Rc::into_raw(rc.clone()); - let rc2 = unsafe { Rc::from_raw(ptr) }; - - assert_eq!(unsafe { &*ptr }.to_string(), "123"); - assert_eq!(rc2.to_string(), "123"); - } - - #[test] - fn get_mut() { - let mut x = Rc::new(3); - *Rc::get_mut(&mut x).unwrap() = 4; - assert_eq!(*x, 4); - let y = x.clone(); - assert!(Rc::get_mut(&mut x).is_none()); - drop(y); - assert!(Rc::get_mut(&mut x).is_some()); - let _w = Rc::downgrade(&x); - assert!(Rc::get_mut(&mut x).is_none()); - } - - #[test] - fn test_cowrc_clone_make_unique() { - let mut cow0 = Rc::new(75); - let mut cow1 = cow0.clone(); - let mut cow2 = cow1.clone(); - - assert!(75 == *Rc::make_mut(&mut cow0)); - assert!(75 == *Rc::make_mut(&mut cow1)); - assert!(75 == *Rc::make_mut(&mut cow2)); - - *Rc::make_mut(&mut cow0) += 1; - *Rc::make_mut(&mut cow1) += 2; - *Rc::make_mut(&mut cow2) += 3; - - assert!(76 == *cow0); - assert!(77 == *cow1); - assert!(78 == *cow2); - - // none should point to the same backing memory - assert!(*cow0 != *cow1); - assert!(*cow0 != *cow2); - assert!(*cow1 != *cow2); - } - - #[test] - fn test_cowrc_clone_unique2() { - let mut cow0 = Rc::new(75); - let cow1 = cow0.clone(); - let cow2 = cow1.clone(); - - assert!(75 == *cow0); - assert!(75 == *cow1); - assert!(75 == *cow2); - - *Rc::make_mut(&mut cow0) += 1; - - assert!(76 == *cow0); - assert!(75 == *cow1); - assert!(75 == *cow2); - - // cow1 and cow2 should share the same contents - // cow0 should have a unique reference - assert!(*cow0 != *cow1); - assert!(*cow0 != *cow2); - assert!(*cow1 == *cow2); - } - - #[test] - fn test_cowrc_clone_weak() { - let mut cow0 = Rc::new(75); - let cow1_weak = Rc::downgrade(&cow0); - - assert!(75 == *cow0); - assert!(75 == *cow1_weak.upgrade().unwrap()); - - *Rc::make_mut(&mut cow0) += 1; - - assert!(76 == *cow0); - assert!(cow1_weak.upgrade().is_none()); - } - - #[test] - fn test_show() { - let foo = Rc::new(75); - assert_eq!(format!("{:?}", foo), "75"); - } - - #[test] - fn test_unsized() { - let foo: Rc<[i32]> = Rc::new([1, 2, 3]); - assert_eq!(foo, foo.clone()); - } - - #[test] - fn test_from_owned() { - let foo = 123; - let foo_rc = Rc::from(foo); - assert!(123 == *foo_rc); - } - - #[test] - fn test_new_weak() { - let foo: Weak<usize> = Weak::new(); - assert!(foo.upgrade().is_none()); - } - - #[test] - fn test_ptr_eq() { - let five = Rc::new(5); - let same_five = five.clone(); - let other_five = Rc::new(5); - - assert!(Rc::ptr_eq(&five, &same_five)); - assert!(!Rc::ptr_eq(&five, &other_five)); - } - - #[test] - fn test_from_str() { - let r: Rc<str> = Rc::from("foo"); - - assert_eq!(&r[..], "foo"); - } - - #[test] - fn test_copy_from_slice() { - let s: &[u32] = &[1, 2, 3]; - let r: Rc<[u32]> = Rc::from(s); - - assert_eq!(&r[..], [1, 2, 3]); - } - - #[test] - fn test_clone_from_slice() { - #[derive(Clone, Debug, Eq, PartialEq)] - struct X(u32); - - let s: &[X] = &[X(1), X(2), X(3)]; - let r: Rc<[X]> = Rc::from(s); - - assert_eq!(&r[..], s); - } - - #[test] - #[should_panic] - fn test_clone_from_slice_panic() { - use std::string::{String, ToString}; - - struct Fail(u32, String); - - impl Clone for Fail { - fn clone(&self) -> Fail { - if self.0 == 2 { - panic!(); - } - Fail(self.0, self.1.clone()) - } - } - - let s: &[Fail] = &[ - Fail(0, "foo".to_string()), - Fail(1, "bar".to_string()), - Fail(2, "baz".to_string()), - ]; - - // Should panic, but not cause memory corruption - let _r: Rc<[Fail]> = Rc::from(s); - } - - #[test] - fn test_from_box() { - let b: Box<u32> = box 123; - let r: Rc<u32> = Rc::from(b); - - assert_eq!(*r, 123); - } - - #[test] - fn test_from_box_str() { - use std::string::String; - - let s = String::from("foo").into_boxed_str(); - let r: Rc<str> = Rc::from(s); - - assert_eq!(&r[..], "foo"); - } - - #[test] - fn test_from_box_slice() { - let s = vec![1, 2, 3].into_boxed_slice(); - let r: Rc<[u32]> = Rc::from(s); - - assert_eq!(&r[..], [1, 2, 3]); - } - - #[test] - fn test_from_box_trait() { - use std::fmt::Display; - use std::string::ToString; - - let b: Box<dyn Display> = box 123; - let r: Rc<dyn Display> = Rc::from(b); - - assert_eq!(r.to_string(), "123"); - } - - #[test] - fn test_from_box_trait_zero_sized() { - use std::fmt::Debug; - - let b: Box<dyn Debug> = box (); - let r: Rc<dyn Debug> = Rc::from(b); - - assert_eq!(format!("{:?}", r), "()"); - } - - #[test] - fn test_from_vec() { - let v = vec![1, 2, 3]; - let r: Rc<[u32]> = Rc::from(v); - - assert_eq!(&r[..], [1, 2, 3]); - } - - #[test] - fn test_downcast() { - use std::any::Any; - - let r1: Rc<dyn Any> = Rc::new(i32::max_value()); - let r2: Rc<dyn Any> = Rc::new("abc"); - - assert!(r1.clone().downcast::<u32>().is_err()); - - let r1i32 = r1.downcast::<i32>(); - assert!(r1i32.is_ok()); - assert_eq!(r1i32.unwrap(), Rc::new(i32::max_value())); - - assert!(r2.clone().downcast::<i32>().is_err()); - - let r2str = r2.downcast::<&'static str>(); - assert!(r2str.is_ok()); - assert_eq!(r2str.unwrap(), Rc::new("abc")); - } -} - #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> borrow::Borrow<T> for Rc<T> { fn borrow(&self) -> &T { @@ -2002,3 +1887,22 @@ impl<T: ?Sized> AsRef<T> for Rc<T> { #[stable(feature = "pin", since = "1.33.0")] impl<T: ?Sized> Unpin for Rc<T> { } + +unsafe fn data_offset<T: ?Sized>(ptr: *const T) -> isize { + // Align the unsized value to the end of the `RcBox`. + // Because it is ?Sized, it will always be the last field in memory. + data_offset_align(align_of_val(&*ptr)) +} + +/// Computes the offset of the data field within `RcBox`. +/// +/// Unlike [`data_offset`], this doesn't need the pointer, but it works only on `T: Sized`. +fn data_offset_sized<T>() -> isize { + data_offset_align(align_of::<T>()) +} + +#[inline] +fn data_offset_align(align: usize) -> isize { + let layout = Layout::new::<RcBox<()>>(); + (layout.size() + layout.padding_needed_for(align)) as isize +} diff --git a/src/liballoc/rc/tests.rs b/src/liballoc/rc/tests.rs new file mode 100644 index 00000000000..6fd3f909357 --- /dev/null +++ b/src/liballoc/rc/tests.rs @@ -0,0 +1,439 @@ +use super::*; + +use std::boxed::Box; +use std::cell::RefCell; +use std::option::Option::{self, None, Some}; +use std::result::Result::{Err, Ok}; +use std::mem::drop; +use std::clone::Clone; +use std::convert::{From, TryInto}; + +#[test] +fn test_clone() { + let x = Rc::new(RefCell::new(5)); + let y = x.clone(); + *x.borrow_mut() = 20; + assert_eq!(*y.borrow(), 20); +} + +#[test] +fn test_simple() { + let x = Rc::new(5); + assert_eq!(*x, 5); +} + +#[test] +fn test_simple_clone() { + let x = Rc::new(5); + let y = x.clone(); + assert_eq!(*x, 5); + assert_eq!(*y, 5); +} + +#[test] +fn test_destructor() { + let x: Rc<Box<_>> = Rc::new(box 5); + assert_eq!(**x, 5); +} + +#[test] +fn test_live() { + let x = Rc::new(5); + let y = Rc::downgrade(&x); + assert!(y.upgrade().is_some()); +} + +#[test] +fn test_dead() { + let x = Rc::new(5); + let y = Rc::downgrade(&x); + drop(x); + assert!(y.upgrade().is_none()); +} + +#[test] +fn weak_self_cyclic() { + struct Cycle { + x: RefCell<Option<Weak<Cycle>>>, + } + + let a = Rc::new(Cycle { x: RefCell::new(None) }); + let b = Rc::downgrade(&a.clone()); + *a.x.borrow_mut() = Some(b); + + // hopefully we don't double-free (or leak)... +} + +#[test] +fn is_unique() { + let x = Rc::new(3); + assert!(Rc::is_unique(&x)); + let y = x.clone(); + assert!(!Rc::is_unique(&x)); + drop(y); + assert!(Rc::is_unique(&x)); + let w = Rc::downgrade(&x); + assert!(!Rc::is_unique(&x)); + drop(w); + assert!(Rc::is_unique(&x)); +} + +#[test] +fn test_strong_count() { + let a = Rc::new(0); + assert!(Rc::strong_count(&a) == 1); + let w = Rc::downgrade(&a); + assert!(Rc::strong_count(&a) == 1); + let b = w.upgrade().expect("upgrade of live rc failed"); + assert!(Rc::strong_count(&b) == 2); + assert!(Rc::strong_count(&a) == 2); + drop(w); + drop(a); + assert!(Rc::strong_count(&b) == 1); + let c = b.clone(); + assert!(Rc::strong_count(&b) == 2); + assert!(Rc::strong_count(&c) == 2); +} + +#[test] +fn test_weak_count() { + let a = Rc::new(0); + assert!(Rc::strong_count(&a) == 1); + assert!(Rc::weak_count(&a) == 0); + let w = Rc::downgrade(&a); + assert!(Rc::strong_count(&a) == 1); + assert!(Rc::weak_count(&a) == 1); + drop(w); + assert!(Rc::strong_count(&a) == 1); + assert!(Rc::weak_count(&a) == 0); + let c = a.clone(); + assert!(Rc::strong_count(&a) == 2); + assert!(Rc::weak_count(&a) == 0); + drop(c); +} + +#[test] +fn weak_counts() { + assert_eq!(Weak::weak_count(&Weak::<u64>::new()), None); + assert_eq!(Weak::strong_count(&Weak::<u64>::new()), 0); + + let a = Rc::new(0); + let w = Rc::downgrade(&a); + assert_eq!(Weak::strong_count(&w), 1); + assert_eq!(Weak::weak_count(&w), Some(1)); + let w2 = w.clone(); + assert_eq!(Weak::strong_count(&w), 1); + assert_eq!(Weak::weak_count(&w), Some(2)); + assert_eq!(Weak::strong_count(&w2), 1); + assert_eq!(Weak::weak_count(&w2), Some(2)); + drop(w); + assert_eq!(Weak::strong_count(&w2), 1); + assert_eq!(Weak::weak_count(&w2), Some(1)); + let a2 = a.clone(); + assert_eq!(Weak::strong_count(&w2), 2); + assert_eq!(Weak::weak_count(&w2), Some(1)); + drop(a2); + drop(a); + assert_eq!(Weak::strong_count(&w2), 0); + assert_eq!(Weak::weak_count(&w2), Some(1)); + drop(w2); +} + +#[test] +fn try_unwrap() { + let x = Rc::new(3); + assert_eq!(Rc::try_unwrap(x), Ok(3)); + let x = Rc::new(4); + let _y = x.clone(); + assert_eq!(Rc::try_unwrap(x), Err(Rc::new(4))); + let x = Rc::new(5); + let _w = Rc::downgrade(&x); + assert_eq!(Rc::try_unwrap(x), Ok(5)); +} + +#[test] +fn into_from_raw() { + let x = Rc::new(box "hello"); + let y = x.clone(); + + let x_ptr = Rc::into_raw(x); + drop(y); + unsafe { + assert_eq!(**x_ptr, "hello"); + + let x = Rc::from_raw(x_ptr); + assert_eq!(**x, "hello"); + + assert_eq!(Rc::try_unwrap(x).map(|x| *x), Ok("hello")); + } +} + +#[test] +fn test_into_from_raw_unsized() { + use std::fmt::Display; + use std::string::ToString; + + let rc: Rc<str> = Rc::from("foo"); + + let ptr = Rc::into_raw(rc.clone()); + let rc2 = unsafe { Rc::from_raw(ptr) }; + + assert_eq!(unsafe { &*ptr }, "foo"); + assert_eq!(rc, rc2); + + let rc: Rc<dyn Display> = Rc::new(123); + + let ptr = Rc::into_raw(rc.clone()); + let rc2 = unsafe { Rc::from_raw(ptr) }; + + assert_eq!(unsafe { &*ptr }.to_string(), "123"); + assert_eq!(rc2.to_string(), "123"); +} + +#[test] +fn get_mut() { + let mut x = Rc::new(3); + *Rc::get_mut(&mut x).unwrap() = 4; + assert_eq!(*x, 4); + let y = x.clone(); + assert!(Rc::get_mut(&mut x).is_none()); + drop(y); + assert!(Rc::get_mut(&mut x).is_some()); + let _w = Rc::downgrade(&x); + assert!(Rc::get_mut(&mut x).is_none()); +} + +#[test] +fn test_cowrc_clone_make_unique() { + let mut cow0 = Rc::new(75); + let mut cow1 = cow0.clone(); + let mut cow2 = cow1.clone(); + + assert!(75 == *Rc::make_mut(&mut cow0)); + assert!(75 == *Rc::make_mut(&mut cow1)); + assert!(75 == *Rc::make_mut(&mut cow2)); + + *Rc::make_mut(&mut cow0) += 1; + *Rc::make_mut(&mut cow1) += 2; + *Rc::make_mut(&mut cow2) += 3; + + assert!(76 == *cow0); + assert!(77 == *cow1); + assert!(78 == *cow2); + + // none should point to the same backing memory + assert!(*cow0 != *cow1); + assert!(*cow0 != *cow2); + assert!(*cow1 != *cow2); +} + +#[test] +fn test_cowrc_clone_unique2() { + let mut cow0 = Rc::new(75); + let cow1 = cow0.clone(); + let cow2 = cow1.clone(); + + assert!(75 == *cow0); + assert!(75 == *cow1); + assert!(75 == *cow2); + + *Rc::make_mut(&mut cow0) += 1; + + assert!(76 == *cow0); + assert!(75 == *cow1); + assert!(75 == *cow2); + + // cow1 and cow2 should share the same contents + // cow0 should have a unique reference + assert!(*cow0 != *cow1); + assert!(*cow0 != *cow2); + assert!(*cow1 == *cow2); +} + +#[test] +fn test_cowrc_clone_weak() { + let mut cow0 = Rc::new(75); + let cow1_weak = Rc::downgrade(&cow0); + + assert!(75 == *cow0); + assert!(75 == *cow1_weak.upgrade().unwrap()); + + *Rc::make_mut(&mut cow0) += 1; + + assert!(76 == *cow0); + assert!(cow1_weak.upgrade().is_none()); +} + +#[test] +fn test_show() { + let foo = Rc::new(75); + assert_eq!(format!("{:?}", foo), "75"); +} + +#[test] +fn test_unsized() { + let foo: Rc<[i32]> = Rc::new([1, 2, 3]); + assert_eq!(foo, foo.clone()); +} + +#[test] +fn test_from_owned() { + let foo = 123; + let foo_rc = Rc::from(foo); + assert!(123 == *foo_rc); +} + +#[test] +fn test_new_weak() { + let foo: Weak<usize> = Weak::new(); + assert!(foo.upgrade().is_none()); +} + +#[test] +fn test_ptr_eq() { + let five = Rc::new(5); + let same_five = five.clone(); + let other_five = Rc::new(5); + + assert!(Rc::ptr_eq(&five, &same_five)); + assert!(!Rc::ptr_eq(&five, &other_five)); +} + +#[test] +fn test_from_str() { + let r: Rc<str> = Rc::from("foo"); + + assert_eq!(&r[..], "foo"); +} + +#[test] +fn test_copy_from_slice() { + let s: &[u32] = &[1, 2, 3]; + let r: Rc<[u32]> = Rc::from(s); + + assert_eq!(&r[..], [1, 2, 3]); +} + +#[test] +fn test_clone_from_slice() { + #[derive(Clone, Debug, Eq, PartialEq)] + struct X(u32); + + let s: &[X] = &[X(1), X(2), X(3)]; + let r: Rc<[X]> = Rc::from(s); + + assert_eq!(&r[..], s); +} + +#[test] +#[should_panic] +fn test_clone_from_slice_panic() { + use std::string::{String, ToString}; + + struct Fail(u32, String); + + impl Clone for Fail { + fn clone(&self) -> Fail { + if self.0 == 2 { + panic!(); + } + Fail(self.0, self.1.clone()) + } + } + + let s: &[Fail] = &[ + Fail(0, "foo".to_string()), + Fail(1, "bar".to_string()), + Fail(2, "baz".to_string()), + ]; + + // Should panic, but not cause memory corruption + let _r: Rc<[Fail]> = Rc::from(s); +} + +#[test] +fn test_from_box() { + let b: Box<u32> = box 123; + let r: Rc<u32> = Rc::from(b); + + assert_eq!(*r, 123); +} + +#[test] +fn test_from_box_str() { + use std::string::String; + + let s = String::from("foo").into_boxed_str(); + let r: Rc<str> = Rc::from(s); + + assert_eq!(&r[..], "foo"); +} + +#[test] +fn test_from_box_slice() { + let s = vec![1, 2, 3].into_boxed_slice(); + let r: Rc<[u32]> = Rc::from(s); + + assert_eq!(&r[..], [1, 2, 3]); +} + +#[test] +fn test_from_box_trait() { + use std::fmt::Display; + use std::string::ToString; + + let b: Box<dyn Display> = box 123; + let r: Rc<dyn Display> = Rc::from(b); + + assert_eq!(r.to_string(), "123"); +} + +#[test] +fn test_from_box_trait_zero_sized() { + use std::fmt::Debug; + + let b: Box<dyn Debug> = box (); + let r: Rc<dyn Debug> = Rc::from(b); + + assert_eq!(format!("{:?}", r), "()"); +} + +#[test] +fn test_from_vec() { + let v = vec![1, 2, 3]; + let r: Rc<[u32]> = Rc::from(v); + + assert_eq!(&r[..], [1, 2, 3]); +} + +#[test] +fn test_downcast() { + use std::any::Any; + + let r1: Rc<dyn Any> = Rc::new(i32::max_value()); + let r2: Rc<dyn Any> = Rc::new("abc"); + + assert!(r1.clone().downcast::<u32>().is_err()); + + let r1i32 = r1.downcast::<i32>(); + assert!(r1i32.is_ok()); + assert_eq!(r1i32.unwrap(), Rc::new(i32::max_value())); + + assert!(r2.clone().downcast::<i32>().is_err()); + + let r2str = r2.downcast::<&'static str>(); + assert!(r2str.is_ok()); + assert_eq!(r2str.unwrap(), Rc::new("abc")); +} + +#[test] +fn test_array_from_slice() { + let v = vec![1, 2, 3]; + let r: Rc<[u32]> = Rc::from(v); + + let a: Result<Rc<[u32; 3]>, _> = r.clone().try_into(); + assert!(a.is_ok()); + + let a: Result<Rc<[u32; 2]>, _> = r.clone().try_into(); + assert!(a.is_err()); +} diff --git a/src/liballoc/slice.rs b/src/liballoc/slice.rs index f4b2d463778..881d499c074 100644 --- a/src/liballoc/slice.rs +++ b/src/liballoc/slice.rs @@ -123,12 +123,12 @@ pub use core::slice::{RChunks, RChunksMut, RChunksExact, RChunksExactMut}; //////////////////////////////////////////////////////////////////////////////// // HACK(japaric) needed for the implementation of `vec!` macro during testing -// NB see the hack module in this file for more details +// N.B., see the `hack` module in this file for more details. #[cfg(test)] pub use hack::into_vec; // HACK(japaric) needed for the implementation of `Vec::clone` during testing -// NB see the hack module in this file for more details +// N.B., see the `hack` module in this file for more details. #[cfg(test)] pub use hack::to_vec; @@ -137,17 +137,16 @@ pub use hack::to_vec; // `core::slice::SliceExt` - we need to supply these functions for the // `test_permutations` test mod hack { - use core::mem; - use crate::boxed::Box; use crate::vec::Vec; #[cfg(test)] use crate::string::ToString; - pub fn into_vec<T>(mut b: Box<[T]>) -> Vec<T> { + pub fn into_vec<T>(b: Box<[T]>) -> Vec<T> { unsafe { - let xs = Vec::from_raw_parts(b.as_mut_ptr(), b.len(), b.len()); - mem::forget(b); + let len = b.len(); + let b = Box::into_raw(b); + let xs = Vec::from_raw_parts(b as *mut T, len, len); xs } } @@ -376,7 +375,7 @@ impl<T> [T] { pub fn to_vec(&self) -> Vec<T> where T: Clone { - // NB see hack module in this file + // N.B., see the `hack` module in this file for more details. hack::to_vec(self) } @@ -397,7 +396,7 @@ impl<T> [T] { #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn into_vec(self: Box<Self>) -> Vec<T> { - // NB see hack module in this file + // N.B., see the `hack` module in this file for more details. hack::into_vec(self) } @@ -485,6 +484,57 @@ impl<T> [T] { } buf } + + /// Flattens a slice of `T` into a single value `Self::Output`. + /// + /// # Examples + /// + /// ``` + /// assert_eq!(["hello", "world"].concat(), "helloworld"); + /// assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + pub fn concat<Item: ?Sized>(&self) -> <Self as Concat<Item>>::Output + where Self: Concat<Item> + { + Concat::concat(self) + } + + /// Flattens a slice of `T` into a single value `Self::Output`, placing a + /// given separator between each. + /// + /// # Examples + /// + /// ``` + /// assert_eq!(["hello", "world"].join(" "), "hello world"); + /// assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]); + /// assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]); + /// ``` + #[stable(feature = "rename_connect_to_join", since = "1.3.0")] + pub fn join<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output + where Self: Join<Separator> + { + Join::join(self, sep) + } + + /// Flattens a slice of `T` into a single value `Self::Output`, placing a + /// given separator between each. + /// + /// # Examples + /// + /// ``` + /// # #![allow(deprecated)] + /// assert_eq!(["hello", "world"].connect(" "), "hello world"); + /// assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_deprecated(since = "1.3.0", reason = "renamed to join")] + pub fn connect<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output + where Self: Join<Separator> + { + Join::join(self, sep) + } + } #[lang = "slice_u8_alloc"] @@ -528,75 +578,84 @@ impl [u8] { //////////////////////////////////////////////////////////////////////////////// // Extension traits for slices over specific kinds of data //////////////////////////////////////////////////////////////////////////////// -#[unstable(feature = "slice_concat_ext", - reason = "trait should not have to exist", - issue = "27747")] -/// An extension trait for concatenating slices + +/// Helper trait for [`[T]::concat`](../../std/primitive.slice.html#method.concat). +/// +/// Note: the `Item` type parameter is not used in this trait, +/// but it allows impls to be more generic. +/// Without it, we get this error: +/// +/// ```error +/// error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predica +/// --> src/liballoc/slice.rs:608:6 +/// | +/// 608 | impl<T: Clone, V: Borrow<[T]>> Concat for [V] { +/// | ^ unconstrained type parameter +/// ``` +/// +/// This is because there could exist `V` types with multiple `Borrow<[_]>` impls, +/// such that multiple `T` types would apply: /// -/// While this trait is unstable, the methods are stable. `SliceConcatExt` is -/// included in the [standard library prelude], so you can use [`join()`] and -/// [`concat()`] as if they existed on `[T]` itself. +/// ``` +/// # #[allow(dead_code)] +/// pub struct Foo(Vec<u32>, Vec<String>); /// -/// [standard library prelude]: ../../std/prelude/index.html -/// [`join()`]: #tymethod.join -/// [`concat()`]: #tymethod.concat -pub trait SliceConcatExt<T: ?Sized> { - #[unstable(feature = "slice_concat_ext", - reason = "trait should not have to exist", - issue = "27747")] +/// impl std::borrow::Borrow<[u32]> for Foo { +/// fn borrow(&self) -> &[u32] { &self.0 } +/// } +/// +/// impl std::borrow::Borrow<[String]> for Foo { +/// fn borrow(&self) -> &[String] { &self.1 } +/// } +/// ``` +#[unstable(feature = "slice_concat_trait", issue = "27747")] +pub trait Concat<Item: ?Sized> { + #[unstable(feature = "slice_concat_trait", issue = "27747")] /// The resulting type after concatenation type Output; - /// Flattens a slice of `T` into a single value `Self::Output`. - /// - /// # Examples - /// - /// ``` - /// assert_eq!(["hello", "world"].concat(), "helloworld"); - /// assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - fn concat(&self) -> Self::Output; + /// Implementation of [`[T]::concat`](../../std/primitive.slice.html#method.concat) + #[unstable(feature = "slice_concat_trait", issue = "27747")] + fn concat(slice: &Self) -> Self::Output; +} - /// Flattens a slice of `T` into a single value `Self::Output`, placing a - /// given separator between each. - /// - /// # Examples - /// - /// ``` - /// assert_eq!(["hello", "world"].join(" "), "hello world"); - /// assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]); - /// ``` - #[stable(feature = "rename_connect_to_join", since = "1.3.0")] - fn join(&self, sep: &T) -> Self::Output; +/// Helper trait for [`[T]::join`](../../std/primitive.slice.html#method.join) +#[unstable(feature = "slice_concat_trait", issue = "27747")] +pub trait Join<Separator> { + #[unstable(feature = "slice_concat_trait", issue = "27747")] + /// The resulting type after concatenation + type Output; - #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_deprecated(since = "1.3.0", reason = "renamed to join")] - fn connect(&self, sep: &T) -> Self::Output; + /// Implementation of [`[T]::join`](../../std/primitive.slice.html#method.join) + #[unstable(feature = "slice_concat_trait", issue = "27747")] + fn join(slice: &Self, sep: Separator) -> Self::Output; } -#[unstable(feature = "slice_concat_ext", - reason = "trait should not have to exist", - issue = "27747")] -impl<T: Clone, V: Borrow<[T]>> SliceConcatExt<T> for [V] { +#[unstable(feature = "slice_concat_ext", issue = "27747")] +impl<T: Clone, V: Borrow<[T]>> Concat<T> for [V] { type Output = Vec<T>; - fn concat(&self) -> Vec<T> { - let size = self.iter().map(|slice| slice.borrow().len()).sum(); + fn concat(slice: &Self) -> Vec<T> { + let size = slice.iter().map(|slice| slice.borrow().len()).sum(); let mut result = Vec::with_capacity(size); - for v in self { + for v in slice { result.extend_from_slice(v.borrow()) } result } +} - fn join(&self, sep: &T) -> Vec<T> { - let mut iter = self.iter(); +#[unstable(feature = "slice_concat_ext", issue = "27747")] +impl<T: Clone, V: Borrow<[T]>> Join<&T> for [V] { + type Output = Vec<T>; + + fn join(slice: &Self, sep: &T) -> Vec<T> { + let mut iter = slice.iter(); let first = match iter.next() { Some(first) => first, None => return vec![], }; - let size = self.iter().map(|slice| slice.borrow().len()).sum::<usize>() + self.len() - 1; + let size = slice.iter().map(|v| v.borrow().len()).sum::<usize>() + slice.len() - 1; let mut result = Vec::with_capacity(size); result.extend_from_slice(first.borrow()); @@ -606,9 +665,28 @@ impl<T: Clone, V: Borrow<[T]>> SliceConcatExt<T> for [V] { } result } +} - fn connect(&self, sep: &T) -> Vec<T> { - self.join(sep) +#[unstable(feature = "slice_concat_ext", issue = "27747")] +impl<T: Clone, V: Borrow<[T]>> Join<&[T]> for [V] { + type Output = Vec<T>; + + fn join(slice: &Self, sep: &[T]) -> Vec<T> { + let mut iter = slice.iter(); + let first = match iter.next() { + Some(first) => first, + None => return vec![], + }; + let size = slice.iter().map(|v| v.borrow().len()).sum::<usize>() + + sep.len() * (slice.len() - 1); + let mut result = Vec::with_capacity(size); + result.extend_from_slice(first.borrow()); + + for v in iter { + result.extend_from_slice(sep); + result.extend_from_slice(v.borrow()) + } + result } } diff --git a/src/liballoc/str.rs b/src/liballoc/str.rs index a36804bddff..9a1342c30d5 100644 --- a/src/liballoc/str.rs +++ b/src/liballoc/str.rs @@ -28,7 +28,7 @@ // It's cleaner to just turn off the unused_imports warning than to fix them. #![allow(unused_imports)] -use core::borrow::Borrow; +use core::borrow::{Borrow, BorrowMut}; use core::str::pattern::{Pattern, Searcher, ReverseSearcher, DoubleEndedSearcher}; use core::mem; use core::ptr; @@ -37,7 +37,7 @@ use core::unicode::conversions; use crate::borrow::ToOwned; use crate::boxed::Box; -use crate::slice::{SliceConcatExt, SliceIndex}; +use crate::slice::{Concat, Join, SliceIndex}; use crate::string::String; use crate::vec::Vec; @@ -68,26 +68,29 @@ pub use core::str::pattern; pub use core::str::EncodeUtf16; #[stable(feature = "split_ascii_whitespace", since = "1.34.0")] pub use core::str::SplitAsciiWhitespace; +#[stable(feature = "str_escape", since = "1.34.0")] +pub use core::str::{EscapeDebug, EscapeDefault, EscapeUnicode}; -#[unstable(feature = "slice_concat_ext", - reason = "trait should not have to exist", - issue = "27747")] -impl<S: Borrow<str>> SliceConcatExt<str> for [S] { +/// Note: `str` in `Concat<str>` is not meaningful here. +/// This type parameter of the trait only exists to enable another impl. +#[unstable(feature = "slice_concat_ext", issue = "27747")] +impl<S: Borrow<str>> Concat<str> for [S] { type Output = String; - fn concat(&self) -> String { - self.join("") + fn concat(slice: &Self) -> String { + Join::join(slice, "") } +} + +#[unstable(feature = "slice_concat_ext", issue = "27747")] +impl<S: Borrow<str>> Join<&str> for [S] { + type Output = String; - fn join(&self, sep: &str) -> String { + fn join(slice: &Self, sep: &str) -> String { unsafe { - String::from_utf8_unchecked( join_generic_copy(self, sep.as_bytes()) ) + String::from_utf8_unchecked( join_generic_copy(slice, sep.as_bytes()) ) } } - - fn connect(&self, sep: &str) -> String { - self.join(sep) - } } macro_rules! spezialize_for_lengths { @@ -128,7 +131,7 @@ macro_rules! copy_slice_and_advance { // Optimized join implementation that works for both Vec<T> (T: Copy) and String's inner vec // Currently (2018-05-13) there is a bug with type inference and specialization (see issue #36262) -// For this reason SliceConcatExt<T> is not specialized for T: Copy and SliceConcatExt<str> is the +// For this reason SliceConcat<T> is not specialized for T: Copy and SliceConcat<str> is the // only user of this function. It is left in place for the time when that is fixed. // // the bounds for String-join are S: Borrow<str> and for Vec-join Borrow<[T]> @@ -188,6 +191,14 @@ impl Borrow<str> for String { } } +#[stable(feature = "string_borrow_mut", since = "1.36.0")] +impl BorrowMut<str> for String { + #[inline] + fn borrow_mut(&mut self) -> &mut str { + &mut self[..] + } +} + #[stable(feature = "rust1", since = "1.0.0")] impl ToOwned for str { type Owned = String; @@ -197,7 +208,7 @@ impl ToOwned for str { } fn clone_into(&self, target: &mut String) { - let mut b = mem::replace(target, String::new()).into_bytes(); + let mut b = mem::take(target).into_bytes(); self.as_bytes().clone_into(&mut b); *target = unsafe { String::from_utf8_unchecked(b) } } @@ -421,6 +432,13 @@ impl str { /// /// assert_eq!(new_year, new_year.to_uppercase()); /// ``` + /// + /// One character can become multiple: + /// ``` + /// let s = "tschüß"; + /// + /// assert_eq!("TSCHÜSS", s.to_uppercase()); + /// ``` #[stable(feature = "unicode_case_mapping", since = "1.2.0")] pub fn to_uppercase(&self) -> String { let mut s = String::with_capacity(self.len()); @@ -571,4 +589,3 @@ impl str { pub unsafe fn from_boxed_utf8_unchecked(v: Box<[u8]>) -> Box<str> { Box::from_raw(Box::into_raw(v) as *mut str) } - diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs index a3e2098695f..eca726cd410 100644 --- a/src/liballoc/string.rs +++ b/src/liballoc/string.rs @@ -552,7 +552,7 @@ impl String { /// assert_eq!("Hello �World", output); /// ``` #[stable(feature = "rust1", since = "1.0.0")] - pub fn from_utf8_lossy<'a>(v: &'a [u8]) -> Cow<'a, str> { + pub fn from_utf8_lossy(v: &[u8]) -> Cow<'_, str> { let mut iter = lossy::Utf8Lossy::from_bytes(v).chunks(); let (first_valid, first_broken) = if let Some(chunk) = iter.next() { @@ -1200,8 +1200,8 @@ impl String { /// Retains only the characters specified by the predicate. /// /// In other words, remove all characters `c` such that `f(c)` returns `false`. - /// This method operates in place and preserves the order of the retained - /// characters. + /// This method operates in place, visiting each character exactly once in the + /// original order, and preserves the order of the retained characters. /// /// # Examples /// @@ -1212,6 +1212,16 @@ impl String { /// /// assert_eq!(s, "foobar"); /// ``` + /// + /// The exact order may be useful for tracking external state, like an index. + /// + /// ``` + /// let mut s = String::from("abcde"); + /// let keep = [false, true, true, false, true]; + /// let mut i = 0; + /// s.retain(|_| (keep[i], i += 1).0); + /// assert_eq!(s, "bce"); + /// ``` #[inline] #[stable(feature = "string_retain", since = "1.26.0")] pub fn retain<F>(&mut self, mut f: F) @@ -1828,6 +1838,7 @@ impl PartialEq for String { macro_rules! impl_eq { ($lhs:ty, $rhs: ty) => { #[stable(feature = "rust1", since = "1.0.0")] + #[allow(unused_lifetimes)] impl<'a, 'b> PartialEq<$rhs> for $lhs { #[inline] fn eq(&self, other: &$rhs) -> bool { PartialEq::eq(&self[..], &other[..]) } @@ -1836,6 +1847,7 @@ macro_rules! impl_eq { } #[stable(feature = "rust1", since = "1.0.0")] + #[allow(unused_lifetimes)] impl<'a, 'b> PartialEq<$lhs> for $rhs { #[inline] fn eq(&self, other: &$lhs) -> bool { PartialEq::eq(&self[..], &other[..]) } @@ -2179,6 +2191,14 @@ impl From<&str> for String { } } +#[stable(feature = "from_ref_string", since = "1.35.0")] +impl From<&String> for String { + #[inline] + fn from(s: &String) -> String { + s.clone() + } +} + // note: test pulls in libstd, which causes errors here #[cfg(not(test))] #[stable(feature = "string_from_box", since = "1.18.0")] @@ -2367,6 +2387,11 @@ impl Iterator for Drain<'_> { fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() } + + #[inline] + fn last(mut self) -> Option<char> { + self.next_back() + } } #[stable(feature = "drain", since = "1.6.0")] diff --git a/src/liballoc/sync.rs b/src/liballoc/sync.rs index b7d7995b540..7d3b2656a7b 100644 --- a/src/liballoc/sync.rs +++ b/src/liballoc/sync.rs @@ -7,21 +7,23 @@ //! [arc]: struct.Arc.html use core::any::Any; +use core::array::LengthAtMost32; use core::sync::atomic; use core::sync::atomic::Ordering::{Acquire, Relaxed, Release, SeqCst}; use core::borrow; use core::fmt; use core::cmp::{self, Ordering}; +use core::iter; use core::intrinsics::abort; -use core::mem::{self, align_of_val, size_of_val}; +use core::mem::{self, align_of, align_of_val, size_of_val}; use core::ops::{Deref, Receiver, CoerceUnsized, DispatchFromDyn}; use core::pin::Pin; use core::ptr::{self, NonNull}; use core::marker::{Unpin, Unsize, PhantomData}; use core::hash::{Hash, Hasher}; use core::{isize, usize}; -use core::convert::From; -use core::slice::from_raw_parts_mut; +use core::convert::{From, TryFrom}; +use core::slice::{self, from_raw_parts_mut}; use crate::alloc::{Global, Alloc, Layout, box_free, handle_alloc_error}; use crate::boxed::Box; @@ -29,6 +31,9 @@ use crate::rc::is_dangling; use crate::string::String; use crate::vec::Vec; +#[cfg(test)] +mod tests; + /// A soft limit on the amount of references that may be made to an `Arc`. /// /// Going above this limit will abort your program (although not @@ -206,6 +211,19 @@ impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Arc<U>> for Arc<T> {} #[unstable(feature = "dispatch_from_dyn", issue = "0")] impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Arc<U>> for Arc<T> {} +impl<T: ?Sized> Arc<T> { + fn from_inner(ptr: NonNull<ArcInner<T>>) -> Self { + Self { + ptr, + phantom: PhantomData, + } + } + + unsafe fn from_ptr(ptr: *mut ArcInner<T>) -> Self { + Self::from_inner(NonNull::new_unchecked(ptr)) + } +} + /// `Weak` is a version of [`Arc`] that holds a non-owning reference to the /// managed value. The value is accessed by calling [`upgrade`] on the `Weak` /// pointer, which returns an [`Option`]`<`[`Arc`]`<T>>`. @@ -290,7 +308,7 @@ impl<T> Arc<T> { weak: atomic::AtomicUsize::new(1), data, }; - Arc { ptr: Box::into_raw_non_null(x), phantom: PhantomData } + Self::from_inner(Box::into_raw_non_null(x)) } /// Constructs a new `Pin<Arc<T>>`. If `T` does not implement `Unpin`, then @@ -356,9 +374,9 @@ impl<T: ?Sized> Arc<T> { /// ``` /// use std::sync::Arc; /// - /// let x = Arc::new(10); + /// let x = Arc::new("hello".to_owned()); /// let x_ptr = Arc::into_raw(x); - /// assert_eq!(unsafe { *x_ptr }, 10); + /// assert_eq!(unsafe { &*x_ptr }, "hello"); /// ``` #[stable(feature = "rc_raw", since = "1.17.0")] pub fn into_raw(this: Self) -> *const T { @@ -382,13 +400,13 @@ impl<T: ?Sized> Arc<T> { /// ``` /// use std::sync::Arc; /// - /// let x = Arc::new(10); + /// let x = Arc::new("hello".to_owned()); /// let x_ptr = Arc::into_raw(x); /// /// unsafe { /// // Convert back to an `Arc` to prevent leak. /// let x = Arc::from_raw(x_ptr); - /// assert_eq!(*x, 10); + /// assert_eq!(&*x, "hello"); /// /// // Further calls to `Arc::from_raw(x_ptr)` would be memory unsafe. /// } @@ -397,20 +415,13 @@ impl<T: ?Sized> Arc<T> { /// ``` #[stable(feature = "rc_raw", since = "1.17.0")] pub unsafe fn from_raw(ptr: *const T) -> Self { - // Align the unsized value to the end of the ArcInner. - // Because it is ?Sized, it will always be the last field in memory. - let align = align_of_val(&*ptr); - let layout = Layout::new::<ArcInner<()>>(); - let offset = (layout.size() + layout.padding_needed_for(align)) as isize; + let offset = data_offset(ptr); // Reverse the offset to find the original ArcInner. let fake_ptr = ptr as *mut ArcInner<T>; let arc_ptr = set_data_ptr(fake_ptr, (ptr as *mut u8).offset(-offset)); - Arc { - ptr: NonNull::new_unchecked(arc_ptr), - phantom: PhantomData, - } + Self::from_ptr(arc_ptr) } /// Consumes the `Arc`, returning the wrapped pointer as `NonNull<T>`. @@ -422,10 +433,10 @@ impl<T: ?Sized> Arc<T> { /// /// use std::sync::Arc; /// - /// let x = Arc::new(10); + /// let x = Arc::new("hello".to_owned()); /// let ptr = Arc::into_raw_non_null(x); - /// let deref = unsafe { *ptr.as_ref() }; - /// assert_eq!(deref, 10); + /// let deref = unsafe { ptr.as_ref() }; + /// assert_eq!(deref, "hello"); /// ``` #[unstable(feature = "rc_into_raw_non_null", issue = "47336")] #[inline] @@ -581,21 +592,28 @@ impl<T: ?Sized> Arc<T> { } impl<T: ?Sized> Arc<T> { - // Allocates an `ArcInner<T>` with sufficient space for an unsized value - unsafe fn allocate_for_ptr(ptr: *const T) -> *mut ArcInner<T> { - // Calculate layout using the given value. + /// Allocates an `ArcInner<T>` with sufficient space for + /// an unsized value where the value has the layout provided. + /// + /// The function `mem_to_arcinner` is called with the data pointer + /// and must return back a (potentially fat)-pointer for the `ArcInner<T>`. + unsafe fn allocate_for_unsized( + value_layout: Layout, + mem_to_arcinner: impl FnOnce(*mut u8) -> *mut ArcInner<T> + ) -> *mut ArcInner<T> { + // Calculate layout using the given value layout. // Previously, layout was calculated on the expression // `&*(ptr as *const ArcInner<T>)`, but this created a misaligned // reference (see #54908). let layout = Layout::new::<ArcInner<()>>() - .extend(Layout::for_value(&*ptr)).unwrap().0 + .extend(value_layout).unwrap().0 .pad_to_align().unwrap(); let mem = Global.alloc(layout) .unwrap_or_else(|_| handle_alloc_error(layout)); // Initialize the ArcInner - let inner = set_data_ptr(ptr as *mut T, mem.as_ptr() as *mut u8) as *mut ArcInner<T>; + let inner = mem_to_arcinner(mem.as_ptr()); debug_assert_eq!(Layout::for_value(&*inner), layout); ptr::write(&mut (*inner).strong, atomic::AtomicUsize::new(1)); @@ -604,6 +622,15 @@ impl<T: ?Sized> Arc<T> { inner } + /// Allocates an `ArcInner<T>` with sufficient space for an unsized value. + unsafe fn allocate_for_ptr(ptr: *const T) -> *mut ArcInner<T> { + // Allocate for the `ArcInner<T>` using the given value. + Self::allocate_for_unsized( + Layout::for_value(&*ptr), + |mem| set_data_ptr(ptr as *mut T, mem) as *mut ArcInner<T>, + ) + } + fn from_box(v: Box<T>) -> Arc<T> { unsafe { let box_unique = Box::into_unique(v); @@ -621,45 +648,49 @@ impl<T: ?Sized> Arc<T> { // Free the allocation without dropping its contents box_free(box_unique); - Arc { ptr: NonNull::new_unchecked(ptr), phantom: PhantomData } + Self::from_ptr(ptr) } } } -// Sets the data pointer of a `?Sized` raw pointer. -// -// For a slice/trait object, this sets the `data` field and leaves the rest -// unchanged. For a sized raw pointer, this simply sets the pointer. +impl<T> Arc<[T]> { + /// Allocates an `ArcInner<[T]>` with the given length. + unsafe fn allocate_for_slice(len: usize) -> *mut ArcInner<[T]> { + Self::allocate_for_unsized( + Layout::array::<T>(len).unwrap(), + |mem| ptr::slice_from_raw_parts_mut(mem as *mut T, len) as *mut ArcInner<[T]>, + ) + } +} + +/// Sets the data pointer of a `?Sized` raw pointer. +/// +/// For a slice/trait object, this sets the `data` field and leaves the rest +/// unchanged. For a sized raw pointer, this simply sets the pointer. unsafe fn set_data_ptr<T: ?Sized, U>(mut ptr: *mut T, data: *mut U) -> *mut T { ptr::write(&mut ptr as *mut _ as *mut *mut u8, data as *mut u8); ptr } impl<T> Arc<[T]> { - // Copy elements from slice into newly allocated Arc<[T]> - // - // Unsafe because the caller must either take ownership or bind `T: Copy` + /// Copy elements from slice into newly allocated Arc<[T]> + /// + /// Unsafe because the caller must either take ownership or bind `T: Copy`. unsafe fn copy_from_slice(v: &[T]) -> Arc<[T]> { - let v_ptr = v as *const [T]; - let ptr = Self::allocate_for_ptr(v_ptr); + let ptr = Self::allocate_for_slice(v.len()); ptr::copy_nonoverlapping( v.as_ptr(), &mut (*ptr).data as *mut [T] as *mut T, v.len()); - Arc { ptr: NonNull::new_unchecked(ptr), phantom: PhantomData } + Self::from_ptr(ptr) } -} - -// Specialization trait used for From<&[T]> -trait ArcFromSlice<T> { - fn from_slice(slice: &[T]) -> Self; -} -impl<T: Clone> ArcFromSlice<T> for Arc<[T]> { - #[inline] - default fn from_slice(v: &[T]) -> Self { + /// Constructs an `Arc<[T]>` from an iterator known to be of a certain size. + /// + /// Behavior is undefined should the size be wrong. + unsafe fn from_iter_exact(iter: impl iter::Iterator<Item = T>, len: usize) -> Arc<[T]> { // Panic guard while cloning T elements. // In the event of a panic, elements that have been written // into the new ArcInner will be dropped, then the memory freed. @@ -676,37 +707,48 @@ impl<T: Clone> ArcFromSlice<T> for Arc<[T]> { let slice = from_raw_parts_mut(self.elems, self.n_elems); ptr::drop_in_place(slice); - Global.dealloc(self.mem.cast(), self.layout.clone()); + Global.dealloc(self.mem.cast(), self.layout); } } } - unsafe { - let v_ptr = v as *const [T]; - let ptr = Self::allocate_for_ptr(v_ptr); + let ptr = Self::allocate_for_slice(len); - let mem = ptr as *mut _ as *mut u8; - let layout = Layout::for_value(&*ptr); + let mem = ptr as *mut _ as *mut u8; + let layout = Layout::for_value(&*ptr); - // Pointer to first element - let elems = &mut (*ptr).data as *mut [T] as *mut T; + // Pointer to first element + let elems = &mut (*ptr).data as *mut [T] as *mut T; - let mut guard = Guard{ - mem: NonNull::new_unchecked(mem), - elems: elems, - layout: layout, - n_elems: 0, - }; + let mut guard = Guard { + mem: NonNull::new_unchecked(mem), + elems, + layout, + n_elems: 0, + }; - for (i, item) in v.iter().enumerate() { - ptr::write(elems.add(i), item.clone()); - guard.n_elems += 1; - } + for (i, item) in iter.enumerate() { + ptr::write(elems.add(i), item); + guard.n_elems += 1; + } + + // All clear. Forget the guard so it doesn't free the new ArcInner. + mem::forget(guard); - // All clear. Forget the guard so it doesn't free the new ArcInner. - mem::forget(guard); + Self::from_ptr(ptr) + } +} - Arc { ptr: NonNull::new_unchecked(ptr), phantom: PhantomData } +/// Specialization trait used for `From<&[T]>`. +trait ArcFromSlice<T> { + fn from_slice(slice: &[T]) -> Self; +} + +impl<T: Clone> ArcFromSlice<T> for Arc<[T]> { + #[inline] + default fn from_slice(v: &[T]) -> Self { + unsafe { + Self::from_iter_exact(v.iter().cloned(), v.len()) } } } @@ -764,7 +806,7 @@ impl<T: ?Sized> Clone for Arc<T> { } } - Arc { ptr: self.ptr, phantom: PhantomData } + Self::from_inner(self.ptr) } } @@ -1043,7 +1085,7 @@ impl Arc<dyn Any + Send + Sync> { if (*self).is::<T>() { let ptr = self.ptr.cast::<ArcInner<T>>(); mem::forget(self); - Ok(Arc { ptr, phantom: PhantomData }) + Ok(Arc::from_inner(ptr)) } else { Err(self) } @@ -1071,6 +1113,144 @@ impl<T> Weak<T> { ptr: NonNull::new(usize::MAX as *mut ArcInner<T>).expect("MAX is not 0"), } } + + /// Returns a raw pointer to the object `T` pointed to by this `Weak<T>`. + /// + /// It is up to the caller to ensure that the object is still alive when accessing it through + /// the pointer. + /// + /// The pointer may be [`null`] or be dangling in case the object has already been destroyed. + /// + /// # Examples + /// + /// ``` + /// #![feature(weak_into_raw)] + /// + /// use std::sync::Arc; + /// use std::ptr; + /// + /// let strong = Arc::new("hello".to_owned()); + /// let weak = Arc::downgrade(&strong); + /// // Both point to the same object + /// assert!(ptr::eq(&*strong, weak.as_raw())); + /// // The strong here keeps it alive, so we can still access the object. + /// assert_eq!("hello", unsafe { &*weak.as_raw() }); + /// + /// drop(strong); + /// // But not any more. We can do weak.as_raw(), but accessing the pointer would lead to + /// // undefined behaviour. + /// // assert_eq!("hello", unsafe { &*weak.as_raw() }); + /// ``` + /// + /// [`null`]: ../../std/ptr/fn.null.html + #[unstable(feature = "weak_into_raw", issue = "60728")] + pub fn as_raw(&self) -> *const T { + match self.inner() { + None => ptr::null(), + Some(inner) => { + let offset = data_offset_sized::<T>(); + let ptr = inner as *const ArcInner<T>; + // Note: while the pointer we create may already point to dropped value, the + // allocation still lives (it must hold the weak point as long as we are alive). + // Therefore, the offset is OK to do, it won't get out of the allocation. + let ptr = unsafe { (ptr as *const u8).offset(offset) }; + ptr as *const T + } + } + } + + /// Consumes the `Weak<T>` and turns it into a raw pointer. + /// + /// This converts the weak pointer into a raw pointer, preserving the original weak count. It + /// can be turned back into the `Weak<T>` with [`from_raw`]. + /// + /// The same restrictions of accessing the target of the pointer as with + /// [`as_raw`] apply. + /// + /// # Examples + /// + /// ``` + /// #![feature(weak_into_raw)] + /// + /// use std::sync::{Arc, Weak}; + /// + /// let strong = Arc::new("hello".to_owned()); + /// let weak = Arc::downgrade(&strong); + /// let raw = weak.into_raw(); + /// + /// assert_eq!(1, Arc::weak_count(&strong)); + /// assert_eq!("hello", unsafe { &*raw }); + /// + /// drop(unsafe { Weak::from_raw(raw) }); + /// assert_eq!(0, Arc::weak_count(&strong)); + /// ``` + /// + /// [`from_raw`]: struct.Weak.html#method.from_raw + /// [`as_raw`]: struct.Weak.html#method.as_raw + #[unstable(feature = "weak_into_raw", issue = "60728")] + pub fn into_raw(self) -> *const T { + let result = self.as_raw(); + mem::forget(self); + result + } + + /// Converts a raw pointer previously created by [`into_raw`] back into + /// `Weak<T>`. + /// + /// This can be used to safely get a strong reference (by calling [`upgrade`] + /// later) or to deallocate the weak count by dropping the `Weak<T>`. + /// + /// It takes ownership of one weak count. In case a [`null`] is passed, a dangling [`Weak`] is + /// returned. + /// + /// # Safety + /// + /// The pointer must represent one valid weak count. In other words, it must point to `T` which + /// is or *was* managed by an [`Arc`] and the weak count of that [`Arc`] must not have reached + /// 0. It is allowed for the strong count to be 0. + /// + /// # Examples + /// + /// ``` + /// #![feature(weak_into_raw)] + /// + /// use std::sync::{Arc, Weak}; + /// + /// let strong = Arc::new("hello".to_owned()); + /// + /// let raw_1 = Arc::downgrade(&strong).into_raw(); + /// let raw_2 = Arc::downgrade(&strong).into_raw(); + /// + /// assert_eq!(2, Arc::weak_count(&strong)); + /// + /// assert_eq!("hello", &*unsafe { Weak::from_raw(raw_1) }.upgrade().unwrap()); + /// assert_eq!(1, Arc::weak_count(&strong)); + /// + /// drop(strong); + /// + /// // Decrement the last weak count. + /// assert!(unsafe { Weak::from_raw(raw_2) }.upgrade().is_none()); + /// ``` + /// + /// [`null`]: ../../std/ptr/fn.null.html + /// [`into_raw`]: struct.Weak.html#method.into_raw + /// [`upgrade`]: struct.Weak.html#method.upgrade + /// [`Weak`]: struct.Weak.html + /// [`Arc`]: struct.Arc.html + #[unstable(feature = "weak_into_raw", issue = "60728")] + pub unsafe fn from_raw(ptr: *const T) -> Self { + if ptr.is_null() { + Self::new() + } else { + // See Arc::from_raw for details + let offset = data_offset(ptr); + let fake_ptr = ptr as *mut ArcInner<T>; + let ptr = set_data_ptr(fake_ptr, (ptr as *mut u8).offset(-offset)); + Weak { + ptr: NonNull::new(ptr).expect("Invalid pointer passed to from_raw"), + } + } + } } impl<T: ?Sized> Weak<T> { @@ -1126,11 +1306,7 @@ impl<T: ?Sized> Weak<T> { // Relaxed is valid for the same reason it is on Arc's Clone impl match inner.strong.compare_exchange_weak(n, n + 1, Relaxed, Relaxed) { - Ok(_) => return Some(Arc { - // null checked above - ptr: self.ptr, - phantom: PhantomData, - }), + Ok(_) => return Some(Arc::from_inner(self.ptr)), // null checked above Err(old) => n = old, } } @@ -1215,18 +1391,18 @@ impl<T: ?Sized> Weak<T> { /// /// ``` /// #![feature(weak_ptr_eq)] - /// use std::sync::{Arc, Weak}; + /// use std::sync::Arc; /// /// let first_rc = Arc::new(5); /// let first = Arc::downgrade(&first_rc); /// let second = Arc::downgrade(&first_rc); /// - /// assert!(Weak::ptr_eq(&first, &second)); + /// assert!(first.ptr_eq(&second)); /// /// let third_rc = Arc::new(5); /// let third = Arc::downgrade(&third_rc); /// - /// assert!(!Weak::ptr_eq(&first, &third)); + /// assert!(!first.ptr_eq(&third)); /// ``` /// /// Comparing `Weak::new`. @@ -1237,16 +1413,16 @@ impl<T: ?Sized> Weak<T> { /// /// let first = Weak::new(); /// let second = Weak::new(); - /// assert!(Weak::ptr_eq(&first, &second)); + /// assert!(first.ptr_eq(&second)); /// /// let third_rc = Arc::new(()); /// let third = Arc::downgrade(&third_rc); - /// assert!(!Weak::ptr_eq(&first, &third)); + /// assert!(!first.ptr_eq(&third)); /// ``` #[inline] #[unstable(feature = "weak_ptr_eq", issue = "55981")] - pub fn ptr_eq(this: &Self, other: &Self) -> bool { - this.ptr.as_ptr() == other.ptr.as_ptr() + pub fn ptr_eq(&self, other: &Self) -> bool { + self.ptr.as_ptr() == other.ptr.as_ptr() } } @@ -1377,6 +1553,11 @@ impl<T: ?Sized + PartialEq> ArcEqIdent<T> for Arc<T> { } } +/// We're doing this specialization here, and not as a more general optimization on `&T`, because it +/// would otherwise add a cost to all equality checks on refs. We assume that `Arc`s are used to +/// store large values, that are slow to clone, but also heavy to check for equality, causing this +/// cost to pay off more easily. It's also more likely to have two `Arc` clones, that point to +/// the same value, than two `&T`s. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized + Eq> ArcEqIdent<T> for Arc<T> { #[inline] @@ -1646,484 +1827,111 @@ impl<T> From<Vec<T>> for Arc<[T]> { } } -#[cfg(test)] -mod tests { - use std::boxed::Box; - use std::clone::Clone; - use std::sync::mpsc::channel; - use std::mem::drop; - use std::ops::Drop; - use std::option::Option::{self, None, Some}; - use std::sync::atomic::{self, Ordering::{Acquire, SeqCst}}; - use std::thread; - use std::sync::Mutex; - use std::convert::From; - - use super::{Arc, Weak}; - use crate::vec::Vec; - - struct Canary(*mut atomic::AtomicUsize); - - impl Drop for Canary { - fn drop(&mut self) { - unsafe { - match *self { - Canary(c) => { - (*c).fetch_add(1, SeqCst); - } - } - } - } - } - - #[test] - #[cfg_attr(target_os = "emscripten", ignore)] - fn manually_share_arc() { - let v = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; - let arc_v = Arc::new(v); - - let (tx, rx) = channel(); - - let _t = thread::spawn(move || { - let arc_v: Arc<Vec<i32>> = rx.recv().unwrap(); - assert_eq!((*arc_v)[3], 4); - }); - - tx.send(arc_v.clone()).unwrap(); - - assert_eq!((*arc_v)[2], 3); - assert_eq!((*arc_v)[4], 5); - } - - #[test] - fn test_arc_get_mut() { - let mut x = Arc::new(3); - *Arc::get_mut(&mut x).unwrap() = 4; - assert_eq!(*x, 4); - let y = x.clone(); - assert!(Arc::get_mut(&mut x).is_none()); - drop(y); - assert!(Arc::get_mut(&mut x).is_some()); - let _w = Arc::downgrade(&x); - assert!(Arc::get_mut(&mut x).is_none()); - } - - #[test] - fn weak_counts() { - assert_eq!(Weak::weak_count(&Weak::<u64>::new()), None); - assert_eq!(Weak::strong_count(&Weak::<u64>::new()), 0); - - let a = Arc::new(0); - let w = Arc::downgrade(&a); - assert_eq!(Weak::strong_count(&w), 1); - assert_eq!(Weak::weak_count(&w), Some(1)); - let w2 = w.clone(); - assert_eq!(Weak::strong_count(&w), 1); - assert_eq!(Weak::weak_count(&w), Some(2)); - assert_eq!(Weak::strong_count(&w2), 1); - assert_eq!(Weak::weak_count(&w2), Some(2)); - drop(w); - assert_eq!(Weak::strong_count(&w2), 1); - assert_eq!(Weak::weak_count(&w2), Some(1)); - let a2 = a.clone(); - assert_eq!(Weak::strong_count(&w2), 2); - assert_eq!(Weak::weak_count(&w2), Some(1)); - drop(a2); - drop(a); - assert_eq!(Weak::strong_count(&w2), 0); - assert_eq!(Weak::weak_count(&w2), Some(1)); - drop(w2); - } - - #[test] - fn try_unwrap() { - let x = Arc::new(3); - assert_eq!(Arc::try_unwrap(x), Ok(3)); - let x = Arc::new(4); - let _y = x.clone(); - assert_eq!(Arc::try_unwrap(x), Err(Arc::new(4))); - let x = Arc::new(5); - let _w = Arc::downgrade(&x); - assert_eq!(Arc::try_unwrap(x), Ok(5)); - } - - #[test] - fn into_from_raw() { - let x = Arc::new(box "hello"); - let y = x.clone(); - - let x_ptr = Arc::into_raw(x); - drop(y); - unsafe { - assert_eq!(**x_ptr, "hello"); - - let x = Arc::from_raw(x_ptr); - assert_eq!(**x, "hello"); - - assert_eq!(Arc::try_unwrap(x).map(|x| *x), Ok("hello")); - } - } - - #[test] - fn test_into_from_raw_unsized() { - use std::fmt::Display; - use std::string::ToString; - - let arc: Arc<str> = Arc::from("foo"); - - let ptr = Arc::into_raw(arc.clone()); - let arc2 = unsafe { Arc::from_raw(ptr) }; - - assert_eq!(unsafe { &*ptr }, "foo"); - assert_eq!(arc, arc2); - - let arc: Arc<dyn Display> = Arc::new(123); - - let ptr = Arc::into_raw(arc.clone()); - let arc2 = unsafe { Arc::from_raw(ptr) }; - - assert_eq!(unsafe { &*ptr }.to_string(), "123"); - assert_eq!(arc2.to_string(), "123"); - } - - #[test] - fn test_cowarc_clone_make_mut() { - let mut cow0 = Arc::new(75); - let mut cow1 = cow0.clone(); - let mut cow2 = cow1.clone(); - - assert!(75 == *Arc::make_mut(&mut cow0)); - assert!(75 == *Arc::make_mut(&mut cow1)); - assert!(75 == *Arc::make_mut(&mut cow2)); - - *Arc::make_mut(&mut cow0) += 1; - *Arc::make_mut(&mut cow1) += 2; - *Arc::make_mut(&mut cow2) += 3; - - assert!(76 == *cow0); - assert!(77 == *cow1); - assert!(78 == *cow2); - - // none should point to the same backing memory - assert!(*cow0 != *cow1); - assert!(*cow0 != *cow2); - assert!(*cow1 != *cow2); - } - - #[test] - fn test_cowarc_clone_unique2() { - let mut cow0 = Arc::new(75); - let cow1 = cow0.clone(); - let cow2 = cow1.clone(); - - assert!(75 == *cow0); - assert!(75 == *cow1); - assert!(75 == *cow2); - - *Arc::make_mut(&mut cow0) += 1; - assert!(76 == *cow0); - assert!(75 == *cow1); - assert!(75 == *cow2); +#[unstable(feature = "boxed_slice_try_from", issue = "0")] +impl<T, const N: usize> TryFrom<Arc<[T]>> for Arc<[T; N]> +where + [T; N]: LengthAtMost32, +{ + type Error = Arc<[T]>; - // cow1 and cow2 should share the same contents - // cow0 should have a unique reference - assert!(*cow0 != *cow1); - assert!(*cow0 != *cow2); - assert!(*cow1 == *cow2); - } - - #[test] - fn test_cowarc_clone_weak() { - let mut cow0 = Arc::new(75); - let cow1_weak = Arc::downgrade(&cow0); - - assert!(75 == *cow0); - assert!(75 == *cow1_weak.upgrade().unwrap()); - - *Arc::make_mut(&mut cow0) += 1; - - assert!(76 == *cow0); - assert!(cow1_weak.upgrade().is_none()); - } - - #[test] - fn test_live() { - let x = Arc::new(5); - let y = Arc::downgrade(&x); - assert!(y.upgrade().is_some()); - } - - #[test] - fn test_dead() { - let x = Arc::new(5); - let y = Arc::downgrade(&x); - drop(x); - assert!(y.upgrade().is_none()); - } - - #[test] - fn weak_self_cyclic() { - struct Cycle { - x: Mutex<Option<Weak<Cycle>>>, - } - - let a = Arc::new(Cycle { x: Mutex::new(None) }); - let b = Arc::downgrade(&a.clone()); - *a.x.lock().unwrap() = Some(b); - - // hopefully we don't double-free (or leak)... - } - - #[test] - fn drop_arc() { - let mut canary = atomic::AtomicUsize::new(0); - let x = Arc::new(Canary(&mut canary as *mut atomic::AtomicUsize)); - drop(x); - assert!(canary.load(Acquire) == 1); - } - - #[test] - fn drop_arc_weak() { - let mut canary = atomic::AtomicUsize::new(0); - let arc = Arc::new(Canary(&mut canary as *mut atomic::AtomicUsize)); - let arc_weak = Arc::downgrade(&arc); - assert!(canary.load(Acquire) == 0); - drop(arc); - assert!(canary.load(Acquire) == 1); - drop(arc_weak); - } - - #[test] - fn test_strong_count() { - let a = Arc::new(0); - assert!(Arc::strong_count(&a) == 1); - let w = Arc::downgrade(&a); - assert!(Arc::strong_count(&a) == 1); - let b = w.upgrade().expect(""); - assert!(Arc::strong_count(&b) == 2); - assert!(Arc::strong_count(&a) == 2); - drop(w); - drop(a); - assert!(Arc::strong_count(&b) == 1); - let c = b.clone(); - assert!(Arc::strong_count(&b) == 2); - assert!(Arc::strong_count(&c) == 2); - } - - #[test] - fn test_weak_count() { - let a = Arc::new(0); - assert!(Arc::strong_count(&a) == 1); - assert!(Arc::weak_count(&a) == 0); - let w = Arc::downgrade(&a); - assert!(Arc::strong_count(&a) == 1); - assert!(Arc::weak_count(&a) == 1); - let x = w.clone(); - assert!(Arc::weak_count(&a) == 2); - drop(w); - drop(x); - assert!(Arc::strong_count(&a) == 1); - assert!(Arc::weak_count(&a) == 0); - let c = a.clone(); - assert!(Arc::strong_count(&a) == 2); - assert!(Arc::weak_count(&a) == 0); - let d = Arc::downgrade(&c); - assert!(Arc::weak_count(&c) == 1); - assert!(Arc::strong_count(&c) == 2); - - drop(a); - drop(c); - drop(d); - } - - #[test] - fn show_arc() { - let a = Arc::new(5); - assert_eq!(format!("{:?}", a), "5"); - } - - // Make sure deriving works with Arc<T> - #[derive(Eq, Ord, PartialEq, PartialOrd, Clone, Debug, Default)] - struct Foo { - inner: Arc<i32>, - } - - #[test] - fn test_unsized() { - let x: Arc<[i32]> = Arc::new([1, 2, 3]); - assert_eq!(format!("{:?}", x), "[1, 2, 3]"); - let y = Arc::downgrade(&x.clone()); - drop(x); - assert!(y.upgrade().is_none()); - } - - #[test] - fn test_from_owned() { - let foo = 123; - let foo_arc = Arc::from(foo); - assert!(123 == *foo_arc); - } - - #[test] - fn test_new_weak() { - let foo: Weak<usize> = Weak::new(); - assert!(foo.upgrade().is_none()); - } - - #[test] - fn test_ptr_eq() { - let five = Arc::new(5); - let same_five = five.clone(); - let other_five = Arc::new(5); - - assert!(Arc::ptr_eq(&five, &same_five)); - assert!(!Arc::ptr_eq(&five, &other_five)); - } - - #[test] - #[cfg_attr(target_os = "emscripten", ignore)] - fn test_weak_count_locked() { - let mut a = Arc::new(atomic::AtomicBool::new(false)); - let a2 = a.clone(); - let t = thread::spawn(move || { - for _i in 0..1000000 { - Arc::get_mut(&mut a); - } - a.store(true, SeqCst); - }); - - while !a2.load(SeqCst) { - let n = Arc::weak_count(&a2); - assert!(n < 2, "bad weak count: {}", n); + fn try_from(boxed_slice: Arc<[T]>) -> Result<Self, Self::Error> { + if boxed_slice.len() == N { + Ok(unsafe { Arc::from_raw(Arc::into_raw(boxed_slice) as *mut [T; N]) }) + } else { + Err(boxed_slice) } - t.join().unwrap(); } +} - #[test] - fn test_from_str() { - let r: Arc<str> = Arc::from("foo"); - - assert_eq!(&r[..], "foo"); - } - - #[test] - fn test_copy_from_slice() { - let s: &[u32] = &[1, 2, 3]; - let r: Arc<[u32]> = Arc::from(s); - - assert_eq!(&r[..], [1, 2, 3]); +#[stable(feature = "shared_from_iter", since = "1.37.0")] +impl<T> iter::FromIterator<T> for Arc<[T]> { + /// Takes each element in the `Iterator` and collects it into an `Arc<[T]>`. + /// + /// # Performance characteristics + /// + /// ## The general case + /// + /// In the general case, collecting into `Arc<[T]>` is done by first + /// collecting into a `Vec<T>`. That is, when writing the following: + /// + /// ```rust + /// # use std::sync::Arc; + /// let evens: Arc<[u8]> = (0..10).filter(|&x| x % 2 == 0).collect(); + /// # assert_eq!(&*evens, &[0, 2, 4, 6, 8]); + /// ``` + /// + /// this behaves as if we wrote: + /// + /// ```rust + /// # use std::sync::Arc; + /// let evens: Arc<[u8]> = (0..10).filter(|&x| x % 2 == 0) + /// .collect::<Vec<_>>() // The first set of allocations happens here. + /// .into(); // A second allocation for `Arc<[T]>` happens here. + /// # assert_eq!(&*evens, &[0, 2, 4, 6, 8]); + /// ``` + /// + /// This will allocate as many times as needed for constructing the `Vec<T>` + /// and then it will allocate once for turning the `Vec<T>` into the `Arc<[T]>`. + /// + /// ## Iterators of known length + /// + /// When your `Iterator` implements `TrustedLen` and is of an exact size, + /// a single allocation will be made for the `Arc<[T]>`. For example: + /// + /// ```rust + /// # use std::sync::Arc; + /// let evens: Arc<[u8]> = (0..10).collect(); // Just a single allocation happens here. + /// # assert_eq!(&*evens, &*(0..10).collect::<Vec<_>>()); + /// ``` + fn from_iter<I: iter::IntoIterator<Item = T>>(iter: I) -> Self { + ArcFromIter::from_iter(iter.into_iter()) } +} - #[test] - fn test_clone_from_slice() { - #[derive(Clone, Debug, Eq, PartialEq)] - struct X(u32); - - let s: &[X] = &[X(1), X(2), X(3)]; - let r: Arc<[X]> = Arc::from(s); +/// Specialization trait used for collecting into `Arc<[T]>`. +trait ArcFromIter<T, I> { + fn from_iter(iter: I) -> Self; +} - assert_eq!(&r[..], s); +impl<T, I: Iterator<Item = T>> ArcFromIter<T, I> for Arc<[T]> { + default fn from_iter(iter: I) -> Self { + iter.collect::<Vec<T>>().into() } +} - #[test] - #[should_panic] - fn test_clone_from_slice_panic() { - use std::string::{String, ToString}; - - struct Fail(u32, String); +impl<T, I: iter::TrustedLen<Item = T>> ArcFromIter<T, I> for Arc<[T]> { + default fn from_iter(iter: I) -> Self { + // This is the case for a `TrustedLen` iterator. + let (low, high) = iter.size_hint(); + if let Some(high) = high { + debug_assert_eq!( + low, high, + "TrustedLen iterator's size hint is not exact: {:?}", + (low, high) + ); - impl Clone for Fail { - fn clone(&self) -> Fail { - if self.0 == 2 { - panic!(); - } - Fail(self.0, self.1.clone()) + unsafe { + // SAFETY: We need to ensure that the iterator has an exact length and we have. + Arc::from_iter_exact(iter, low) } + } else { + // Fall back to normal implementation. + iter.collect::<Vec<T>>().into() } - - let s: &[Fail] = &[ - Fail(0, "foo".to_string()), - Fail(1, "bar".to_string()), - Fail(2, "baz".to_string()), - ]; - - // Should panic, but not cause memory corruption - let _r: Arc<[Fail]> = Arc::from(s); - } - - #[test] - fn test_from_box() { - let b: Box<u32> = box 123; - let r: Arc<u32> = Arc::from(b); - - assert_eq!(*r, 123); - } - - #[test] - fn test_from_box_str() { - use std::string::String; - - let s = String::from("foo").into_boxed_str(); - let r: Arc<str> = Arc::from(s); - - assert_eq!(&r[..], "foo"); - } - - #[test] - fn test_from_box_slice() { - let s = vec![1, 2, 3].into_boxed_slice(); - let r: Arc<[u32]> = Arc::from(s); - - assert_eq!(&r[..], [1, 2, 3]); } +} - #[test] - fn test_from_box_trait() { - use std::fmt::Display; - use std::string::ToString; - - let b: Box<dyn Display> = box 123; - let r: Arc<dyn Display> = Arc::from(b); - - assert_eq!(r.to_string(), "123"); - } - - #[test] - fn test_from_box_trait_zero_sized() { - use std::fmt::Debug; - - let b: Box<dyn Debug> = box (); - let r: Arc<dyn Debug> = Arc::from(b); - - assert_eq!(format!("{:?}", r), "()"); - } - - #[test] - fn test_from_vec() { - let v = vec![1, 2, 3]; - let r: Arc<[u32]> = Arc::from(v); - - assert_eq!(&r[..], [1, 2, 3]); - } - - #[test] - fn test_downcast() { - use std::any::Any; - - let r1: Arc<dyn Any + Send + Sync> = Arc::new(i32::max_value()); - let r2: Arc<dyn Any + Send + Sync> = Arc::new("abc"); - - assert!(r1.clone().downcast::<u32>().is_err()); - - let r1i32 = r1.downcast::<i32>(); - assert!(r1i32.is_ok()); - assert_eq!(r1i32.unwrap(), Arc::new(i32::max_value())); - - assert!(r2.clone().downcast::<i32>().is_err()); - - let r2str = r2.downcast::<&'static str>(); - assert!(r2str.is_ok()); - assert_eq!(r2str.unwrap(), Arc::new("abc")); +impl<'a, T: 'a + Clone> ArcFromIter<&'a T, slice::Iter<'a, T>> for Arc<[T]> { + fn from_iter(iter: slice::Iter<'a, T>) -> Self { + // Delegate to `impl<T: Clone> From<&[T]> for Arc<[T]>`. + // + // In the case that `T: Copy`, we get to use `ptr::copy_nonoverlapping` + // which is even more performant. + // + // In the fall-back case we have `T: Clone`. This is still better + // than the `TrustedLen` implementation as slices have a known length + // and so we get to avoid calling `size_hint` and avoid the branching. + iter.as_slice().into() } } @@ -2143,3 +1951,23 @@ impl<T: ?Sized> AsRef<T> for Arc<T> { #[stable(feature = "pin", since = "1.33.0")] impl<T: ?Sized> Unpin for Arc<T> { } + +/// Computes the offset of the data field within `ArcInner`. +unsafe fn data_offset<T: ?Sized>(ptr: *const T) -> isize { + // Align the unsized value to the end of the `ArcInner`. + // Because it is `?Sized`, it will always be the last field in memory. + data_offset_align(align_of_val(&*ptr)) +} + +/// Computes the offset of the data field within `ArcInner`. +/// +/// Unlike [`data_offset`], this doesn't need the pointer, but it works only on `T: Sized`. +fn data_offset_sized<T>() -> isize { + data_offset_align(align_of::<T>()) +} + +#[inline] +fn data_offset_align(align: usize) -> isize { + let layout = Layout::new::<ArcInner<()>>(); + (layout.size() + layout.padding_needed_for(align)) as isize +} diff --git a/src/liballoc/sync/tests.rs b/src/liballoc/sync/tests.rs new file mode 100644 index 00000000000..9220f5e0333 --- /dev/null +++ b/src/liballoc/sync/tests.rs @@ -0,0 +1,492 @@ +use super::*; + +use std::boxed::Box; +use std::clone::Clone; +use std::sync::mpsc::channel; +use std::mem::drop; +use std::ops::Drop; +use std::option::Option::{self, None, Some}; +use std::sync::atomic::{self, Ordering::{Acquire, SeqCst}}; +use std::thread; +use std::sync::Mutex; +use std::convert::{From, TryInto}; + +use crate::vec::Vec; + +struct Canary(*mut atomic::AtomicUsize); + +impl Drop for Canary { + fn drop(&mut self) { + unsafe { + match *self { + Canary(c) => { + (*c).fetch_add(1, SeqCst); + } + } + } + } +} + +#[test] +#[cfg_attr(target_os = "emscripten", ignore)] +#[cfg(not(miri))] // Miri does not support threads +fn manually_share_arc() { + let v = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + let arc_v = Arc::new(v); + + let (tx, rx) = channel(); + + let _t = thread::spawn(move || { + let arc_v: Arc<Vec<i32>> = rx.recv().unwrap(); + assert_eq!((*arc_v)[3], 4); + }); + + tx.send(arc_v.clone()).unwrap(); + + assert_eq!((*arc_v)[2], 3); + assert_eq!((*arc_v)[4], 5); +} + +#[test] +fn test_arc_get_mut() { + let mut x = Arc::new(3); + *Arc::get_mut(&mut x).unwrap() = 4; + assert_eq!(*x, 4); + let y = x.clone(); + assert!(Arc::get_mut(&mut x).is_none()); + drop(y); + assert!(Arc::get_mut(&mut x).is_some()); + let _w = Arc::downgrade(&x); + assert!(Arc::get_mut(&mut x).is_none()); +} + +#[test] +fn weak_counts() { + assert_eq!(Weak::weak_count(&Weak::<u64>::new()), None); + assert_eq!(Weak::strong_count(&Weak::<u64>::new()), 0); + + let a = Arc::new(0); + let w = Arc::downgrade(&a); + assert_eq!(Weak::strong_count(&w), 1); + assert_eq!(Weak::weak_count(&w), Some(1)); + let w2 = w.clone(); + assert_eq!(Weak::strong_count(&w), 1); + assert_eq!(Weak::weak_count(&w), Some(2)); + assert_eq!(Weak::strong_count(&w2), 1); + assert_eq!(Weak::weak_count(&w2), Some(2)); + drop(w); + assert_eq!(Weak::strong_count(&w2), 1); + assert_eq!(Weak::weak_count(&w2), Some(1)); + let a2 = a.clone(); + assert_eq!(Weak::strong_count(&w2), 2); + assert_eq!(Weak::weak_count(&w2), Some(1)); + drop(a2); + drop(a); + assert_eq!(Weak::strong_count(&w2), 0); + assert_eq!(Weak::weak_count(&w2), Some(1)); + drop(w2); +} + +#[test] +fn try_unwrap() { + let x = Arc::new(3); + assert_eq!(Arc::try_unwrap(x), Ok(3)); + let x = Arc::new(4); + let _y = x.clone(); + assert_eq!(Arc::try_unwrap(x), Err(Arc::new(4))); + let x = Arc::new(5); + let _w = Arc::downgrade(&x); + assert_eq!(Arc::try_unwrap(x), Ok(5)); +} + +#[test] +fn into_from_raw() { + let x = Arc::new(box "hello"); + let y = x.clone(); + + let x_ptr = Arc::into_raw(x); + drop(y); + unsafe { + assert_eq!(**x_ptr, "hello"); + + let x = Arc::from_raw(x_ptr); + assert_eq!(**x, "hello"); + + assert_eq!(Arc::try_unwrap(x).map(|x| *x), Ok("hello")); + } +} + +#[test] +fn test_into_from_raw_unsized() { + use std::fmt::Display; + use std::string::ToString; + + let arc: Arc<str> = Arc::from("foo"); + + let ptr = Arc::into_raw(arc.clone()); + let arc2 = unsafe { Arc::from_raw(ptr) }; + + assert_eq!(unsafe { &*ptr }, "foo"); + assert_eq!(arc, arc2); + + let arc: Arc<dyn Display> = Arc::new(123); + + let ptr = Arc::into_raw(arc.clone()); + let arc2 = unsafe { Arc::from_raw(ptr) }; + + assert_eq!(unsafe { &*ptr }.to_string(), "123"); + assert_eq!(arc2.to_string(), "123"); +} + +#[test] +fn test_cowarc_clone_make_mut() { + let mut cow0 = Arc::new(75); + let mut cow1 = cow0.clone(); + let mut cow2 = cow1.clone(); + + assert!(75 == *Arc::make_mut(&mut cow0)); + assert!(75 == *Arc::make_mut(&mut cow1)); + assert!(75 == *Arc::make_mut(&mut cow2)); + + *Arc::make_mut(&mut cow0) += 1; + *Arc::make_mut(&mut cow1) += 2; + *Arc::make_mut(&mut cow2) += 3; + + assert!(76 == *cow0); + assert!(77 == *cow1); + assert!(78 == *cow2); + + // none should point to the same backing memory + assert!(*cow0 != *cow1); + assert!(*cow0 != *cow2); + assert!(*cow1 != *cow2); +} + +#[test] +fn test_cowarc_clone_unique2() { + let mut cow0 = Arc::new(75); + let cow1 = cow0.clone(); + let cow2 = cow1.clone(); + + assert!(75 == *cow0); + assert!(75 == *cow1); + assert!(75 == *cow2); + + *Arc::make_mut(&mut cow0) += 1; + assert!(76 == *cow0); + assert!(75 == *cow1); + assert!(75 == *cow2); + + // cow1 and cow2 should share the same contents + // cow0 should have a unique reference + assert!(*cow0 != *cow1); + assert!(*cow0 != *cow2); + assert!(*cow1 == *cow2); +} + +#[test] +fn test_cowarc_clone_weak() { + let mut cow0 = Arc::new(75); + let cow1_weak = Arc::downgrade(&cow0); + + assert!(75 == *cow0); + assert!(75 == *cow1_weak.upgrade().unwrap()); + + *Arc::make_mut(&mut cow0) += 1; + + assert!(76 == *cow0); + assert!(cow1_weak.upgrade().is_none()); +} + +#[test] +fn test_live() { + let x = Arc::new(5); + let y = Arc::downgrade(&x); + assert!(y.upgrade().is_some()); +} + +#[test] +fn test_dead() { + let x = Arc::new(5); + let y = Arc::downgrade(&x); + drop(x); + assert!(y.upgrade().is_none()); +} + +#[test] +fn weak_self_cyclic() { + struct Cycle { + x: Mutex<Option<Weak<Cycle>>>, + } + + let a = Arc::new(Cycle { x: Mutex::new(None) }); + let b = Arc::downgrade(&a.clone()); + *a.x.lock().unwrap() = Some(b); + + // hopefully we don't double-free (or leak)... +} + +#[test] +fn drop_arc() { + let mut canary = atomic::AtomicUsize::new(0); + let x = Arc::new(Canary(&mut canary as *mut atomic::AtomicUsize)); + drop(x); + assert!(canary.load(Acquire) == 1); +} + +#[test] +fn drop_arc_weak() { + let mut canary = atomic::AtomicUsize::new(0); + let arc = Arc::new(Canary(&mut canary as *mut atomic::AtomicUsize)); + let arc_weak = Arc::downgrade(&arc); + assert!(canary.load(Acquire) == 0); + drop(arc); + assert!(canary.load(Acquire) == 1); + drop(arc_weak); +} + +#[test] +fn test_strong_count() { + let a = Arc::new(0); + assert!(Arc::strong_count(&a) == 1); + let w = Arc::downgrade(&a); + assert!(Arc::strong_count(&a) == 1); + let b = w.upgrade().expect(""); + assert!(Arc::strong_count(&b) == 2); + assert!(Arc::strong_count(&a) == 2); + drop(w); + drop(a); + assert!(Arc::strong_count(&b) == 1); + let c = b.clone(); + assert!(Arc::strong_count(&b) == 2); + assert!(Arc::strong_count(&c) == 2); +} + +#[test] +fn test_weak_count() { + let a = Arc::new(0); + assert!(Arc::strong_count(&a) == 1); + assert!(Arc::weak_count(&a) == 0); + let w = Arc::downgrade(&a); + assert!(Arc::strong_count(&a) == 1); + assert!(Arc::weak_count(&a) == 1); + let x = w.clone(); + assert!(Arc::weak_count(&a) == 2); + drop(w); + drop(x); + assert!(Arc::strong_count(&a) == 1); + assert!(Arc::weak_count(&a) == 0); + let c = a.clone(); + assert!(Arc::strong_count(&a) == 2); + assert!(Arc::weak_count(&a) == 0); + let d = Arc::downgrade(&c); + assert!(Arc::weak_count(&c) == 1); + assert!(Arc::strong_count(&c) == 2); + + drop(a); + drop(c); + drop(d); +} + +#[test] +fn show_arc() { + let a = Arc::new(5); + assert_eq!(format!("{:?}", a), "5"); +} + +// Make sure deriving works with Arc<T> +#[derive(Eq, Ord, PartialEq, PartialOrd, Clone, Debug, Default)] +struct Foo { + inner: Arc<i32>, +} + +#[test] +fn test_unsized() { + let x: Arc<[i32]> = Arc::new([1, 2, 3]); + assert_eq!(format!("{:?}", x), "[1, 2, 3]"); + let y = Arc::downgrade(&x.clone()); + drop(x); + assert!(y.upgrade().is_none()); +} + +#[test] +fn test_from_owned() { + let foo = 123; + let foo_arc = Arc::from(foo); + assert!(123 == *foo_arc); +} + +#[test] +fn test_new_weak() { + let foo: Weak<usize> = Weak::new(); + assert!(foo.upgrade().is_none()); +} + +#[test] +fn test_ptr_eq() { + let five = Arc::new(5); + let same_five = five.clone(); + let other_five = Arc::new(5); + + assert!(Arc::ptr_eq(&five, &same_five)); + assert!(!Arc::ptr_eq(&five, &other_five)); +} + +#[test] +#[cfg_attr(target_os = "emscripten", ignore)] +#[cfg(not(miri))] // Miri does not support threads +fn test_weak_count_locked() { + let mut a = Arc::new(atomic::AtomicBool::new(false)); + let a2 = a.clone(); + let t = thread::spawn(move || { + for _i in 0..1000000 { + Arc::get_mut(&mut a); + } + a.store(true, SeqCst); + }); + + while !a2.load(SeqCst) { + let n = Arc::weak_count(&a2); + assert!(n < 2, "bad weak count: {}", n); + } + t.join().unwrap(); +} + +#[test] +fn test_from_str() { + let r: Arc<str> = Arc::from("foo"); + + assert_eq!(&r[..], "foo"); +} + +#[test] +fn test_copy_from_slice() { + let s: &[u32] = &[1, 2, 3]; + let r: Arc<[u32]> = Arc::from(s); + + assert_eq!(&r[..], [1, 2, 3]); +} + +#[test] +fn test_clone_from_slice() { + #[derive(Clone, Debug, Eq, PartialEq)] + struct X(u32); + + let s: &[X] = &[X(1), X(2), X(3)]; + let r: Arc<[X]> = Arc::from(s); + + assert_eq!(&r[..], s); +} + +#[test] +#[should_panic] +fn test_clone_from_slice_panic() { + use std::string::{String, ToString}; + + struct Fail(u32, String); + + impl Clone for Fail { + fn clone(&self) -> Fail { + if self.0 == 2 { + panic!(); + } + Fail(self.0, self.1.clone()) + } + } + + let s: &[Fail] = &[ + Fail(0, "foo".to_string()), + Fail(1, "bar".to_string()), + Fail(2, "baz".to_string()), + ]; + + // Should panic, but not cause memory corruption + let _r: Arc<[Fail]> = Arc::from(s); +} + +#[test] +fn test_from_box() { + let b: Box<u32> = box 123; + let r: Arc<u32> = Arc::from(b); + + assert_eq!(*r, 123); +} + +#[test] +fn test_from_box_str() { + use std::string::String; + + let s = String::from("foo").into_boxed_str(); + let r: Arc<str> = Arc::from(s); + + assert_eq!(&r[..], "foo"); +} + +#[test] +fn test_from_box_slice() { + let s = vec![1, 2, 3].into_boxed_slice(); + let r: Arc<[u32]> = Arc::from(s); + + assert_eq!(&r[..], [1, 2, 3]); +} + +#[test] +fn test_from_box_trait() { + use std::fmt::Display; + use std::string::ToString; + + let b: Box<dyn Display> = box 123; + let r: Arc<dyn Display> = Arc::from(b); + + assert_eq!(r.to_string(), "123"); +} + +#[test] +fn test_from_box_trait_zero_sized() { + use std::fmt::Debug; + + let b: Box<dyn Debug> = box (); + let r: Arc<dyn Debug> = Arc::from(b); + + assert_eq!(format!("{:?}", r), "()"); +} + +#[test] +fn test_from_vec() { + let v = vec![1, 2, 3]; + let r: Arc<[u32]> = Arc::from(v); + + assert_eq!(&r[..], [1, 2, 3]); +} + +#[test] +fn test_downcast() { + use std::any::Any; + + let r1: Arc<dyn Any + Send + Sync> = Arc::new(i32::max_value()); + let r2: Arc<dyn Any + Send + Sync> = Arc::new("abc"); + + assert!(r1.clone().downcast::<u32>().is_err()); + + let r1i32 = r1.downcast::<i32>(); + assert!(r1i32.is_ok()); + assert_eq!(r1i32.unwrap(), Arc::new(i32::max_value())); + + assert!(r2.clone().downcast::<i32>().is_err()); + + let r2str = r2.downcast::<&'static str>(); + assert!(r2str.is_ok()); + assert_eq!(r2str.unwrap(), Arc::new("abc")); +} + +#[test] +fn test_array_from_slice() { + let v = vec![1, 2, 3]; + let r: Arc<[u32]> = Arc::from(v); + + let a: Result<Arc<[u32; 3]>, _> = r.clone().try_into(); + assert!(a.is_ok()); + + let a: Result<Arc<[u32; 2]>, _> = r.clone().try_into(); + assert!(a.is_err()); +} diff --git a/src/liballoc/boxed_test.rs b/src/liballoc/tests.rs index 654eabd0703..ed46ba8a1b9 100644 --- a/src/liballoc/boxed_test.rs +++ b/src/liballoc/tests.rs @@ -1,6 +1,7 @@ //! Test for `boxed` mod. use core::any::Any; +use core::convert::TryInto; use core::ops::Deref; use core::result::Result::{Err, Ok}; use core::clone::Clone; @@ -138,3 +139,15 @@ fn boxed_slice_from_iter() { assert_eq!(boxed.len(), 100); assert_eq!(boxed[7], 7); } + +#[test] +fn test_array_from_slice() { + let v = vec![1, 2, 3]; + let r: Box<[u32]> = v.into_boxed_slice(); + + let a: Result<Box<[u32; 3]>, _> = r.clone().try_into(); + assert!(a.is_ok()); + + let a: Result<Box<[u32; 2]>, _> = r.clone().try_into(); + assert!(a.is_err()); +} diff --git a/src/liballoc/tests/arc.rs b/src/liballoc/tests/arc.rs index 2759b1b1cac..cf2ad2a8e60 100644 --- a/src/liballoc/tests/arc.rs +++ b/src/liballoc/tests/arc.rs @@ -2,6 +2,8 @@ use std::any::Any; use std::sync::{Arc, Weak}; use std::cell::RefCell; use std::cmp::PartialEq; +use std::iter::TrustedLen; +use std::mem; #[test] fn uninhabited() { @@ -85,3 +87,122 @@ fn eq() { assert!(!(x != x)); assert_eq!(*x.0.borrow(), 0); } + +// The test code below is identical to that in `rc.rs`. +// For better maintainability we therefore define this type alias. +type Rc<T> = Arc<T>; + +const SHARED_ITER_MAX: u16 = 100; + +fn assert_trusted_len<I: TrustedLen>(_: &I) {} + +#[test] +fn shared_from_iter_normal() { + // Exercise the base implementation for non-`TrustedLen` iterators. + { + // `Filter` is never `TrustedLen` since we don't + // know statically how many elements will be kept: + let iter = (0..SHARED_ITER_MAX).filter(|x| x % 2 == 0).map(Box::new); + + // Collecting into a `Vec<T>` or `Rc<[T]>` should make no difference: + let vec = iter.clone().collect::<Vec<_>>(); + let rc = iter.collect::<Rc<[_]>>(); + assert_eq!(&*vec, &*rc); + + // Clone a bit and let these get dropped. + { + let _rc_2 = rc.clone(); + let _rc_3 = rc.clone(); + let _rc_4 = Rc::downgrade(&_rc_3); + } + } // Drop what hasn't been here. +} + +#[test] +fn shared_from_iter_trustedlen_normal() { + // Exercise the `TrustedLen` implementation under normal circumstances + // where `size_hint()` matches `(_, Some(exact_len))`. + { + let iter = (0..SHARED_ITER_MAX).map(Box::new); + assert_trusted_len(&iter); + + // Collecting into a `Vec<T>` or `Rc<[T]>` should make no difference: + let vec = iter.clone().collect::<Vec<_>>(); + let rc = iter.collect::<Rc<[_]>>(); + assert_eq!(&*vec, &*rc); + assert_eq!(mem::size_of::<Box<u16>>() * SHARED_ITER_MAX as usize, mem::size_of_val(&*rc)); + + // Clone a bit and let these get dropped. + { + let _rc_2 = rc.clone(); + let _rc_3 = rc.clone(); + let _rc_4 = Rc::downgrade(&_rc_3); + } + } // Drop what hasn't been here. + + // Try a ZST to make sure it is handled well. + { + let iter = (0..SHARED_ITER_MAX).map(|_| ()); + let vec = iter.clone().collect::<Vec<_>>(); + let rc = iter.collect::<Rc<[_]>>(); + assert_eq!(&*vec, &*rc); + assert_eq!(0, mem::size_of_val(&*rc)); + { + let _rc_2 = rc.clone(); + let _rc_3 = rc.clone(); + let _rc_4 = Rc::downgrade(&_rc_3); + } + } +} + +#[test] +#[should_panic = "I've almost got 99 problems."] +fn shared_from_iter_trustedlen_panic() { + // Exercise the `TrustedLen` implementation when `size_hint()` matches + // `(_, Some(exact_len))` but where `.next()` drops before the last iteration. + let iter = (0..SHARED_ITER_MAX) + .map(|val| { + match val { + 98 => panic!("I've almost got 99 problems."), + _ => Box::new(val), + } + }); + assert_trusted_len(&iter); + let _ = iter.collect::<Rc<[_]>>(); + + panic!("I am unreachable."); +} + +#[test] +fn shared_from_iter_trustedlen_no_fuse() { + // Exercise the `TrustedLen` implementation when `size_hint()` matches + // `(_, Some(exact_len))` but where the iterator does not behave in a fused manner. + struct Iter(std::vec::IntoIter<Option<Box<u8>>>); + + unsafe impl TrustedLen for Iter {} + + impl Iterator for Iter { + fn size_hint(&self) -> (usize, Option<usize>) { + (2, Some(2)) + } + + type Item = Box<u8>; + + fn next(&mut self) -> Option<Self::Item> { + self.0.next().flatten() + } + } + + let vec = vec![ + Some(Box::new(42)), + Some(Box::new(24)), + None, + Some(Box::new(12)), + ]; + let iter = Iter(vec.into_iter()); + assert_trusted_len(&iter); + assert_eq!( + &[Box::new(42), Box::new(24)], + &*iter.collect::<Rc<[_]>>() + ); +} diff --git a/src/liballoc/tests/binary_heap.rs b/src/liballoc/tests/binary_heap.rs index 1d4a3edc1ac..0685fa943c0 100644 --- a/src/liballoc/tests/binary_heap.rs +++ b/src/liballoc/tests/binary_heap.rs @@ -282,7 +282,7 @@ fn assert_covariance() { // // Destructors must be called exactly once per element. #[test] -#[cfg(not(miri))] // Miri does not support panics +#[cfg(not(miri))] // Miri does not support catching panics fn panic_safe() { static DROP_COUNTER: AtomicUsize = AtomicUsize::new(0); diff --git a/src/liballoc/tests/btree/map.rs b/src/liballoc/tests/btree/map.rs index f14750089c9..844afe87076 100644 --- a/src/liballoc/tests/btree/map.rs +++ b/src/liballoc/tests/btree/map.rs @@ -226,7 +226,6 @@ fn test_range_equal_empty_cases() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_range_equal_excluded() { let map: BTreeMap<_, _> = (0..5).map(|i| (i, i)).collect(); map.range((Excluded(2), Excluded(2))); @@ -234,7 +233,6 @@ fn test_range_equal_excluded() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_range_backwards_1() { let map: BTreeMap<_, _> = (0..5).map(|i| (i, i)).collect(); map.range((Included(3), Included(2))); @@ -242,7 +240,6 @@ fn test_range_backwards_1() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_range_backwards_2() { let map: BTreeMap<_, _> = (0..5).map(|i| (i, i)).collect(); map.range((Included(3), Excluded(2))); @@ -250,7 +247,6 @@ fn test_range_backwards_2() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_range_backwards_3() { let map: BTreeMap<_, _> = (0..5).map(|i| (i, i)).collect(); map.range((Excluded(3), Included(2))); @@ -258,7 +254,6 @@ fn test_range_backwards_3() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_range_backwards_4() { let map: BTreeMap<_, _> = (0..5).map(|i| (i, i)).collect(); map.range((Excluded(3), Excluded(2))); diff --git a/src/liballoc/tests/btree/set.rs b/src/liballoc/tests/btree/set.rs index 9e031375949..8c3dacd914f 100644 --- a/src/liballoc/tests/btree/set.rs +++ b/src/liballoc/tests/btree/set.rs @@ -69,6 +69,20 @@ fn test_intersection() { check_intersection(&[11, 1, 3, 77, 103, 5, -5], &[2, 11, 77, -9, -42, 5, 3], &[3, 5, 11, 77]); + let large = (0..1000).collect::<Vec<_>>(); + check_intersection(&[], &large, &[]); + check_intersection(&large, &[], &[]); + check_intersection(&[-1], &large, &[]); + check_intersection(&large, &[-1], &[]); + check_intersection(&[0], &large, &[0]); + check_intersection(&large, &[0], &[0]); + check_intersection(&[999], &large, &[999]); + check_intersection(&large, &[999], &[999]); + check_intersection(&[1000], &large, &[]); + check_intersection(&large, &[1000], &[]); + check_intersection(&[11, 5000, 1, 3, 77, 8924, 103], + &large, + &[1, 3, 11, 77, 103]); } #[test] @@ -84,6 +98,18 @@ fn test_difference() { check_difference(&[-5, 11, 22, 33, 40, 42], &[-12, -5, 14, 23, 34, 38, 39, 50], &[11, 22, 33, 40, 42]); + let large = (0..1000).collect::<Vec<_>>(); + check_difference(&[], &large, &[]); + check_difference(&[-1], &large, &[-1]); + check_difference(&[0], &large, &[]); + check_difference(&[999], &large, &[]); + check_difference(&[1000], &large, &[1000]); + check_difference(&[11, 5000, 1, 3, 77, 8924, 103], + &large, + &[5000, 8924]); + check_difference(&large, &[], &large); + check_difference(&large, &[-1], &large); + check_difference(&large, &[1000], &large); } #[test] @@ -115,6 +141,41 @@ fn test_union() { } #[test] +// Only tests the simple function definition with respect to intersection +fn test_is_disjoint() { + let one = [1].iter().collect::<BTreeSet<_>>(); + let two = [2].iter().collect::<BTreeSet<_>>(); + assert!(one.is_disjoint(&two)); +} + +#[test] +// Also tests the trivial function definition of is_superset +fn test_is_subset() { + fn is_subset(a: &[i32], b: &[i32]) -> bool { + let set_a = a.iter().collect::<BTreeSet<_>>(); + let set_b = b.iter().collect::<BTreeSet<_>>(); + set_a.is_subset(&set_b) + } + + assert_eq!(is_subset(&[], &[]), true); + assert_eq!(is_subset(&[], &[1, 2]), true); + assert_eq!(is_subset(&[0], &[1, 2]), false); + assert_eq!(is_subset(&[1], &[1, 2]), true); + assert_eq!(is_subset(&[2], &[1, 2]), true); + assert_eq!(is_subset(&[3], &[1, 2]), false); + assert_eq!(is_subset(&[1, 2], &[1]), false); + assert_eq!(is_subset(&[1, 2], &[1, 2]), true); + assert_eq!(is_subset(&[1, 2], &[2, 3]), false); + let large = (0..1000).collect::<Vec<_>>(); + assert_eq!(is_subset(&[], &large), true); + assert_eq!(is_subset(&large, &[]), false); + assert_eq!(is_subset(&[-1], &large), false); + assert_eq!(is_subset(&[0], &large), true); + assert_eq!(is_subset(&[1, 2], &large), true); + assert_eq!(is_subset(&[999, 1000], &large), false); +} + +#[test] fn test_zip() { let mut x = BTreeSet::new(); x.insert(5); diff --git a/src/liballoc/tests/cow_str.rs b/src/liballoc/tests/cow_str.rs index eb6adb159b0..6f357eda9b8 100644 --- a/src/liballoc/tests/cow_str.rs +++ b/src/liballoc/tests/cow_str.rs @@ -7,9 +7,9 @@ fn check_cow_add_cow() { let borrowed2 = Cow::Borrowed("World!"); let borrow_empty = Cow::Borrowed(""); - let owned1: Cow<str> = Cow::Owned(String::from("Hi, ")); - let owned2: Cow<str> = Cow::Owned(String::from("Rustaceans!")); - let owned_empty: Cow<str> = Cow::Owned(String::new()); + let owned1: Cow<'_, str> = Cow::Owned(String::from("Hi, ")); + let owned2: Cow<'_, str> = Cow::Owned(String::from("Rustaceans!")); + let owned_empty: Cow<'_, str> = Cow::Owned(String::new()); assert_eq!("Hello, World!", borrowed1.clone() + borrowed2.clone()); assert_eq!("Hello, Rustaceans!", borrowed1.clone() + owned2.clone()); @@ -36,8 +36,8 @@ fn check_cow_add_str() { let borrowed = Cow::Borrowed("Hello, "); let borrow_empty = Cow::Borrowed(""); - let owned: Cow<str> = Cow::Owned(String::from("Hi, ")); - let owned_empty: Cow<str> = Cow::Owned(String::new()); + let owned: Cow<'_, str> = Cow::Owned(String::from("Hi, ")); + let owned_empty: Cow<'_, str> = Cow::Owned(String::new()); assert_eq!("Hello, World!", borrowed.clone() + "World!"); @@ -60,9 +60,9 @@ fn check_cow_add_assign_cow() { let borrowed2 = Cow::Borrowed("World!"); let borrow_empty = Cow::Borrowed(""); - let mut owned1: Cow<str> = Cow::Owned(String::from("Hi, ")); - let owned2: Cow<str> = Cow::Owned(String::from("Rustaceans!")); - let owned_empty: Cow<str> = Cow::Owned(String::new()); + let mut owned1: Cow<'_, str> = Cow::Owned(String::from("Hi, ")); + let owned2: Cow<'_, str> = Cow::Owned(String::from("Rustaceans!")); + let owned_empty: Cow<'_, str> = Cow::Owned(String::new()); let mut s = borrowed1.clone(); s += borrow_empty.clone(); @@ -101,8 +101,8 @@ fn check_cow_add_assign_str() { let mut borrowed = Cow::Borrowed("Hello, "); let borrow_empty = Cow::Borrowed(""); - let mut owned: Cow<str> = Cow::Owned(String::from("Hi, ")); - let owned_empty: Cow<str> = Cow::Owned(String::new()); + let mut owned: Cow<'_, str> = Cow::Owned(String::from("Hi, ")); + let owned_empty: Cow<'_, str> = Cow::Owned(String::new()); let mut s = borrowed.clone(); s += ""; @@ -132,10 +132,10 @@ fn check_cow_add_assign_str() { #[test] fn check_cow_clone_from() { - let mut c1: Cow<str> = Cow::Owned(String::with_capacity(25)); + let mut c1: Cow<'_, str> = Cow::Owned(String::with_capacity(25)); let s: String = "hi".to_string(); assert!(s.capacity() < 25); - let c2: Cow<str> = Cow::Owned(s); + let c2: Cow<'_, str> = Cow::Owned(s); c1.clone_from(&c2); assert!(c1.into_owned().capacity() >= 25); } diff --git a/src/liballoc/tests/heap.rs b/src/liballoc/tests/heap.rs index c225ebfa96b..904b3e7e1b0 100644 --- a/src/liballoc/tests/heap.rs +++ b/src/liballoc/tests/heap.rs @@ -1,6 +1,6 @@ use std::alloc::{Global, Alloc, Layout, System}; -/// Issue #45955. +/// Issue #45955 and #62251. #[test] fn alloc_system_overaligned_request() { check_overalign_requests(System) @@ -12,21 +12,23 @@ fn std_heap_overaligned_request() { } fn check_overalign_requests<T: Alloc>(mut allocator: T) { - let size = 8; - let align = 16; // greater than size - let iterations = 100; - unsafe { - let pointers: Vec<_> = (0..iterations).map(|_| { - allocator.alloc(Layout::from_size_align(size, align).unwrap()).unwrap() - }).collect(); - for &ptr in &pointers { - assert_eq!((ptr.as_ptr() as usize) % align, 0, - "Got a pointer less aligned than requested") - } + for &align in &[4, 8, 16, 32] { // less than and bigger than `MIN_ALIGN` + for &size in &[align/2, align-1] { // size less than alignment + let iterations = 128; + unsafe { + let pointers: Vec<_> = (0..iterations).map(|_| { + allocator.alloc(Layout::from_size_align(size, align).unwrap()).unwrap() + }).collect(); + for &ptr in &pointers { + assert_eq!((ptr.as_ptr() as usize) % align, 0, + "Got a pointer less aligned than requested") + } - // Clean up - for &ptr in &pointers { - allocator.dealloc(ptr, Layout::from_size_align(size, align).unwrap()) + // Clean up + for &ptr in &pointers { + allocator.dealloc(ptr, Layout::from_size_align(size, align).unwrap()) + } + } } } } diff --git a/src/liballoc/tests/lib.rs b/src/liballoc/tests/lib.rs index 90921b6af9f..6d774f3fecd 100644 --- a/src/liballoc/tests/lib.rs +++ b/src/liballoc/tests/lib.rs @@ -2,11 +2,12 @@ #![feature(box_syntax)] #![feature(drain_filter)] #![feature(exact_size_is_empty)] +#![feature(option_flattening)] #![feature(pattern)] #![feature(repeat_generic_slice)] +#![feature(trusted_len)] #![feature(try_reserve)] #![feature(unboxed_closures)] -#![feature(vecdeque_rotate)] use std::hash::{Hash, Hasher}; use std::collections::hash_map::DefaultHasher; diff --git a/src/liballoc/tests/linked_list.rs b/src/liballoc/tests/linked_list.rs index 0fbfbdccd45..8a26454c389 100644 --- a/src/liballoc/tests/linked_list.rs +++ b/src/liballoc/tests/linked_list.rs @@ -40,12 +40,10 @@ fn test_basic() { assert_eq!(n.pop_front(), Some(1)); } -#[cfg(test)] fn generate_test() -> LinkedList<i32> { list_from(&[0, 1, 2, 3, 4, 5, 6]) } -#[cfg(test)] fn list_from<T: Clone>(v: &[T]) -> LinkedList<T> { v.iter().cloned().collect() } diff --git a/src/liballoc/tests/rc.rs b/src/liballoc/tests/rc.rs index 18f82e80410..7854ca0fc16 100644 --- a/src/liballoc/tests/rc.rs +++ b/src/liballoc/tests/rc.rs @@ -2,6 +2,8 @@ use std::any::Any; use std::rc::{Rc, Weak}; use std::cell::RefCell; use std::cmp::PartialEq; +use std::mem; +use std::iter::TrustedLen; #[test] fn uninhabited() { @@ -85,3 +87,118 @@ fn eq() { assert!(!(x != x)); assert_eq!(*x.0.borrow(), 0); } + +const SHARED_ITER_MAX: u16 = 100; + +fn assert_trusted_len<I: TrustedLen>(_: &I) {} + +#[test] +fn shared_from_iter_normal() { + // Exercise the base implementation for non-`TrustedLen` iterators. + { + // `Filter` is never `TrustedLen` since we don't + // know statically how many elements will be kept: + let iter = (0..SHARED_ITER_MAX).filter(|x| x % 2 == 0).map(Box::new); + + // Collecting into a `Vec<T>` or `Rc<[T]>` should make no difference: + let vec = iter.clone().collect::<Vec<_>>(); + let rc = iter.collect::<Rc<[_]>>(); + assert_eq!(&*vec, &*rc); + + // Clone a bit and let these get dropped. + { + let _rc_2 = rc.clone(); + let _rc_3 = rc.clone(); + let _rc_4 = Rc::downgrade(&_rc_3); + } + } // Drop what hasn't been here. +} + +#[test] +fn shared_from_iter_trustedlen_normal() { + // Exercise the `TrustedLen` implementation under normal circumstances + // where `size_hint()` matches `(_, Some(exact_len))`. + { + let iter = (0..SHARED_ITER_MAX).map(Box::new); + assert_trusted_len(&iter); + + // Collecting into a `Vec<T>` or `Rc<[T]>` should make no difference: + let vec = iter.clone().collect::<Vec<_>>(); + let rc = iter.collect::<Rc<[_]>>(); + assert_eq!(&*vec, &*rc); + assert_eq!(mem::size_of::<Box<u16>>() * SHARED_ITER_MAX as usize, mem::size_of_val(&*rc)); + + // Clone a bit and let these get dropped. + { + let _rc_2 = rc.clone(); + let _rc_3 = rc.clone(); + let _rc_4 = Rc::downgrade(&_rc_3); + } + } // Drop what hasn't been here. + + // Try a ZST to make sure it is handled well. + { + let iter = (0..SHARED_ITER_MAX).map(|_| ()); + let vec = iter.clone().collect::<Vec<_>>(); + let rc = iter.collect::<Rc<[_]>>(); + assert_eq!(&*vec, &*rc); + assert_eq!(0, mem::size_of_val(&*rc)); + { + let _rc_2 = rc.clone(); + let _rc_3 = rc.clone(); + let _rc_4 = Rc::downgrade(&_rc_3); + } + } +} + +#[test] +#[should_panic = "I've almost got 99 problems."] +fn shared_from_iter_trustedlen_panic() { + // Exercise the `TrustedLen` implementation when `size_hint()` matches + // `(_, Some(exact_len))` but where `.next()` drops before the last iteration. + let iter = (0..SHARED_ITER_MAX) + .map(|val| { + match val { + 98 => panic!("I've almost got 99 problems."), + _ => Box::new(val), + } + }); + assert_trusted_len(&iter); + let _ = iter.collect::<Rc<[_]>>(); + + panic!("I am unreachable."); +} + +#[test] +fn shared_from_iter_trustedlen_no_fuse() { + // Exercise the `TrustedLen` implementation when `size_hint()` matches + // `(_, Some(exact_len))` but where the iterator does not behave in a fused manner. + struct Iter(std::vec::IntoIter<Option<Box<u8>>>); + + unsafe impl TrustedLen for Iter {} + + impl Iterator for Iter { + fn size_hint(&self) -> (usize, Option<usize>) { + (2, Some(2)) + } + + type Item = Box<u8>; + + fn next(&mut self) -> Option<Self::Item> { + self.0.next().flatten() + } + } + + let vec = vec![ + Some(Box::new(42)), + Some(Box::new(24)), + None, + Some(Box::new(12)), + ]; + let iter = Iter(vec.into_iter()); + assert_trusted_len(&iter); + assert_eq!( + &[Box::new(42), Box::new(24)], + &*iter.collect::<Rc<[_]>>() + ); +} diff --git a/src/liballoc/tests/slice.rs b/src/liballoc/tests/slice.rs index feba46b0fad..ad2cd7c95eb 100644 --- a/src/liballoc/tests/slice.rs +++ b/src/liballoc/tests/slice.rs @@ -258,7 +258,6 @@ fn test_swap_remove() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_swap_remove_fail() { let mut v = vec![1]; let _ = v.swap_remove(0); @@ -390,7 +389,7 @@ fn test_reverse() { } #[test] -#[cfg(not(miri))] // Miri does not support entropy +#[cfg(not(miri))] // Miri is too slow fn test_sort() { let mut rng = thread_rng(); @@ -467,10 +466,19 @@ fn test_sort() { } #[test] -#[cfg(not(miri))] // Miri does not support entropy fn test_sort_stability() { - for len in (2..25).chain(500..510) { - for _ in 0..10 { + #[cfg(not(miri))] // Miri is too slow + let large_range = 500..510; + #[cfg(not(miri))] // Miri is too slow + let rounds = 10; + + #[cfg(miri)] + let large_range = 0..0; // empty range + #[cfg(miri)] + let rounds = 1; + + for len in (2..25).chain(large_range) { + for _ in 0..rounds { let mut counts = [0; 10]; // create a vector like [(6, 1), (5, 1), (6, 2), ...], @@ -632,7 +640,6 @@ fn test_insert() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_insert_oob() { let mut a = vec![1, 2, 3]; a.insert(4, 5); @@ -657,7 +664,6 @@ fn test_remove() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_remove_fail() { let mut a = vec![1]; let _ = a.remove(0); @@ -939,7 +945,6 @@ fn test_windowsator() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_windowsator_0() { let v = &[1, 2, 3, 4]; let _it = v.windows(0); @@ -964,7 +969,6 @@ fn test_chunksator() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_chunksator_0() { let v = &[1, 2, 3, 4]; let _it = v.chunks(0); @@ -989,7 +993,6 @@ fn test_chunks_exactator() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_chunks_exactator_0() { let v = &[1, 2, 3, 4]; let _it = v.chunks_exact(0); @@ -1014,7 +1017,6 @@ fn test_rchunksator() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_rchunksator_0() { let v = &[1, 2, 3, 4]; let _it = v.rchunks(0); @@ -1039,7 +1041,6 @@ fn test_rchunks_exactator() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_rchunks_exactator_0() { let v = &[1, 2, 3, 4]; let _it = v.rchunks_exact(0); @@ -1092,7 +1093,6 @@ fn test_vec_default() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_overflow_does_not_cause_segfault() { let mut v = vec![]; v.reserve_exact(!0); @@ -1102,7 +1102,6 @@ fn test_overflow_does_not_cause_segfault() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_overflow_does_not_cause_segfault_managed() { let mut v = vec![Rc::new(1)]; v.reserve_exact(!0); @@ -1278,7 +1277,6 @@ fn test_mut_chunks_rev() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_mut_chunks_0() { let mut v = [1, 2, 3, 4]; let _it = v.chunks_mut(0); @@ -1311,7 +1309,6 @@ fn test_mut_chunks_exact_rev() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_mut_chunks_exact_0() { let mut v = [1, 2, 3, 4]; let _it = v.chunks_exact_mut(0); @@ -1344,7 +1341,6 @@ fn test_mut_rchunks_rev() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_mut_rchunks_0() { let mut v = [1, 2, 3, 4]; let _it = v.rchunks_mut(0); @@ -1377,7 +1373,6 @@ fn test_mut_rchunks_exact_rev() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_mut_rchunks_exact_0() { let mut v = [1, 2, 3, 4]; let _it = v.rchunks_exact_mut(0); @@ -1411,7 +1406,7 @@ fn test_box_slice_clone() { #[test] #[allow(unused_must_use)] // here, we care about the side effects of `.clone()` #[cfg_attr(target_os = "emscripten", ignore)] -#[cfg(not(miri))] // Miri does not support panics +#[cfg(not(miri))] // Miri does not support threads fn test_box_slice_clone_panics() { use std::sync::Arc; use std::sync::atomic::{AtomicUsize, Ordering}; @@ -1476,7 +1471,6 @@ fn test_copy_from_slice() { #[test] #[should_panic(expected = "destination and source slices have different lengths")] -#[cfg(not(miri))] // Miri does not support panics fn test_copy_from_slice_dst_longer() { let src = [0, 1, 2, 3]; let mut dst = [0; 5]; @@ -1485,7 +1479,6 @@ fn test_copy_from_slice_dst_longer() { #[test] #[should_panic(expected = "destination and source slices have different lengths")] -#[cfg(not(miri))] // Miri does not support panics fn test_copy_from_slice_dst_shorter() { let src = [0, 1, 2, 3]; let mut dst = [0; 3]; @@ -1605,7 +1598,7 @@ thread_local!(static SILENCE_PANIC: Cell<bool> = Cell::new(false)); #[test] #[cfg_attr(target_os = "emscripten", ignore)] // no threads -#[cfg(not(miri))] // Miri does not support panics +#[cfg(not(miri))] // Miri does not support threads fn panic_safe() { let prev = panic::take_hook(); panic::set_hook(Box::new(move |info| { diff --git a/src/liballoc/tests/str.rs b/src/liballoc/tests/str.rs index f465d67dc93..c5198ca39fe 100644 --- a/src/liballoc/tests/str.rs +++ b/src/liballoc/tests/str.rs @@ -351,7 +351,6 @@ mod slice_index { // to be used in `should_panic`) #[test] #[should_panic(expected = "out of bounds")] - #[cfg(not(miri))] // Miri does not support panics fn assert_range_eq_can_fail_by_panic() { assert_range_eq!("abc", 0..5, "abc"); } @@ -361,7 +360,6 @@ mod slice_index { // to be used in `should_panic`) #[test] #[should_panic(expected = "==")] - #[cfg(not(miri))] // Miri does not support panics fn assert_range_eq_can_fail_by_inequality() { assert_range_eq!("abc", 0..2, "abc"); } @@ -409,7 +407,6 @@ mod slice_index { #[test] #[should_panic(expected = $expect_msg)] - #[cfg(not(miri))] // Miri does not support panics fn index_fail() { let v: String = $data.into(); let v: &str = &v; @@ -418,7 +415,6 @@ mod slice_index { #[test] #[should_panic(expected = $expect_msg)] - #[cfg(not(miri))] // Miri does not support panics fn index_mut_fail() { let mut v: String = $data.into(); let v: &mut str = &mut v; @@ -514,7 +510,6 @@ mod slice_index { #[test] #[should_panic] - #[cfg(not(miri))] // Miri does not support panics fn test_slice_fail() { &"中华Việt Nam"[0..2]; } @@ -666,14 +661,12 @@ mod slice_index { // check the panic includes the prefix of the sliced string #[test] #[should_panic(expected="byte index 1024 is out of bounds of `Lorem ipsum dolor sit amet")] - #[cfg(not(miri))] // Miri does not support panics fn test_slice_fail_truncated_1() { &LOREM_PARAGRAPH[..1024]; } // check the truncation in the panic message #[test] #[should_panic(expected="luctus, im`[...]")] - #[cfg(not(miri))] // Miri does not support panics fn test_slice_fail_truncated_2() { &LOREM_PARAGRAPH[..1024]; } @@ -688,7 +681,6 @@ fn test_str_slice_rangetoinclusive_ok() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_str_slice_rangetoinclusive_notok() { let s = "abcαβγ"; &s[..=3]; @@ -704,7 +696,6 @@ fn test_str_slicemut_rangetoinclusive_ok() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_str_slicemut_rangetoinclusive_notok() { let mut s = "abcαβγ".to_owned(); let s: &mut str = &mut s; @@ -894,7 +885,6 @@ fn test_as_bytes() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_as_bytes_fail() { // Don't double free. (I'm not sure if this exercises the // original problem code path anymore.) @@ -984,7 +974,6 @@ fn test_split_at_mut() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_split_at_boundscheck() { let s = "ศไทย中华Việt Nam"; s.split_at(1); @@ -1120,6 +1109,16 @@ fn test_iterator_last() { } #[test] +fn test_chars_debug() { + let s = "ศไทย中华Việt Nam"; + let c = s.chars(); + assert_eq!( + format!("{:?}", c), + r#"Chars(['ศ', 'ไ', 'ท', 'ย', '中', '华', 'V', 'i', 'ệ', 't', ' ', 'N', 'a', 'm'])"# + ); +} + +#[test] fn test_bytesator() { let s = "ศไทย中华Việt Nam"; let v = [ diff --git a/src/liballoc/tests/string.rs b/src/liballoc/tests/string.rs index 7e93d84fe3b..765210e5aa6 100644 --- a/src/liballoc/tests/string.rs +++ b/src/liballoc/tests/string.rs @@ -54,11 +54,11 @@ fn test_from_utf8() { #[test] fn test_from_utf8_lossy() { let xs = b"hello"; - let ys: Cow<str> = "hello".into_cow(); + let ys: Cow<'_, str> = "hello".into_cow(); assert_eq!(String::from_utf8_lossy(xs), ys); let xs = "ศไทย中华Việt Nam".as_bytes(); - let ys: Cow<str> = "ศไทย中华Việt Nam".into_cow(); + let ys: Cow<'_, str> = "ศไทย中华Việt Nam".into_cow(); assert_eq!(String::from_utf8_lossy(xs), ys); let xs = b"Hello\xC2 There\xFF Goodbye"; @@ -231,7 +231,6 @@ fn test_split_off_empty() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_split_off_past_end() { let orig = "Hello, world!"; let mut split = String::from(orig); @@ -240,7 +239,6 @@ fn test_split_off_past_end() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_split_off_mid_char() { let mut orig = String::from("山"); orig.split_off(1); @@ -289,7 +287,6 @@ fn test_str_truncate_invalid_len() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_str_truncate_split_codepoint() { let mut s = String::from("\u{FC}"); // ü s.truncate(1); @@ -324,7 +321,6 @@ fn remove() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn remove_bad() { "ศ".to_string().remove(1); } @@ -360,13 +356,11 @@ fn insert() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn insert_bad1() { "".to_string().insert(1, 't'); } #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn insert_bad2() { "ệ".to_string().insert(1, 't'); } @@ -447,7 +441,6 @@ fn test_replace_range() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_replace_range_char_boundary() { let mut s = "Hello, 世界!".to_owned(); s.replace_range(..8, ""); @@ -464,7 +457,6 @@ fn test_replace_range_inclusive_range() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_replace_range_out_of_bounds() { let mut s = String::from("12345"); s.replace_range(5..6, "789"); @@ -472,7 +464,6 @@ fn test_replace_range_out_of_bounds() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_replace_range_inclusive_out_of_bounds() { let mut s = String::from("12345"); s.replace_range(5..=5, "789"); diff --git a/src/liballoc/tests/vec.rs b/src/liballoc/tests/vec.rs index 6e4ca1d90e6..6e8ffe18522 100644 --- a/src/liballoc/tests/vec.rs +++ b/src/liballoc/tests/vec.rs @@ -1,5 +1,3 @@ -#![cfg(not(miri))] - use std::borrow::Cow; use std::mem::size_of; use std::{usize, isize}; @@ -368,7 +366,6 @@ fn test_vec_truncate_drop() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_vec_truncate_fail() { struct BadElem(i32); impl Drop for BadElem { @@ -392,7 +389,6 @@ fn test_index() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_index_out_of_bounds() { let vec = vec![1, 2, 3]; let _ = vec[3]; @@ -400,7 +396,6 @@ fn test_index_out_of_bounds() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_slice_out_of_bounds_1() { let x = vec![1, 2, 3, 4, 5]; &x[!0..]; @@ -408,7 +403,6 @@ fn test_slice_out_of_bounds_1() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_slice_out_of_bounds_2() { let x = vec![1, 2, 3, 4, 5]; &x[..6]; @@ -416,7 +410,6 @@ fn test_slice_out_of_bounds_2() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_slice_out_of_bounds_3() { let x = vec![1, 2, 3, 4, 5]; &x[!0..4]; @@ -424,7 +417,6 @@ fn test_slice_out_of_bounds_3() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_slice_out_of_bounds_4() { let x = vec![1, 2, 3, 4, 5]; &x[1..6]; @@ -432,7 +424,6 @@ fn test_slice_out_of_bounds_4() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_slice_out_of_bounds_5() { let x = vec![1, 2, 3, 4, 5]; &x[3..2]; @@ -440,7 +431,6 @@ fn test_slice_out_of_bounds_5() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_swap_remove_empty() { let mut vec = Vec::<i32>::new(); vec.swap_remove(0); @@ -511,7 +501,6 @@ fn test_drain_items_zero_sized() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_drain_out_of_bounds() { let mut v = vec![1, 2, 3, 4, 5]; v.drain(5..6); @@ -585,7 +574,6 @@ fn test_drain_max_vec_size() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_drain_inclusive_out_of_bounds() { let mut v = vec![1, 2, 3, 4, 5]; v.drain(5..=5); @@ -615,7 +603,6 @@ fn test_splice_inclusive_range() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_splice_out_of_bounds() { let mut v = vec![1, 2, 3, 4, 5]; let a = [10, 11, 12]; @@ -624,7 +611,6 @@ fn test_splice_out_of_bounds() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_splice_inclusive_out_of_bounds() { let mut v = vec![1, 2, 3, 4, 5]; let a = [10, 11, 12]; @@ -959,6 +945,115 @@ fn drain_filter_complex() { } #[test] +#[cfg(not(miri))] // Miri does not support catching panics +fn drain_filter_consumed_panic() { + use std::rc::Rc; + use std::sync::Mutex; + + struct Check { + index: usize, + drop_counts: Rc<Mutex<Vec<usize>>>, + }; + + impl Drop for Check { + fn drop(&mut self) { + self.drop_counts.lock().unwrap()[self.index] += 1; + println!("drop: {}", self.index); + } + } + + let check_count = 10; + let drop_counts = Rc::new(Mutex::new(vec![0_usize; check_count])); + let mut data: Vec<Check> = (0..check_count) + .map(|index| Check { index, drop_counts: Rc::clone(&drop_counts) }) + .collect(); + + let _ = std::panic::catch_unwind(move || { + let filter = |c: &mut Check| { + if c.index == 2 { + panic!("panic at index: {}", c.index); + } + // Verify that if the filter could panic again on another element + // that it would not cause a double panic and all elements of the + // vec would still be dropped exactly once. + if c.index == 4 { + panic!("panic at index: {}", c.index); + } + c.index < 6 + }; + let drain = data.drain_filter(filter); + + // NOTE: The DrainFilter is explictly consumed + drain.for_each(drop); + }); + + let drop_counts = drop_counts.lock().unwrap(); + assert_eq!(check_count, drop_counts.len()); + + for (index, count) in drop_counts.iter().cloned().enumerate() { + assert_eq!(1, count, "unexpected drop count at index: {} (count: {})", index, count); + } +} + +#[test] +#[cfg(not(miri))] // Miri does not support catching panics +fn drain_filter_unconsumed_panic() { + use std::rc::Rc; + use std::sync::Mutex; + + struct Check { + index: usize, + drop_counts: Rc<Mutex<Vec<usize>>>, + }; + + impl Drop for Check { + fn drop(&mut self) { + self.drop_counts.lock().unwrap()[self.index] += 1; + println!("drop: {}", self.index); + } + } + + let check_count = 10; + let drop_counts = Rc::new(Mutex::new(vec![0_usize; check_count])); + let mut data: Vec<Check> = (0..check_count) + .map(|index| Check { index, drop_counts: Rc::clone(&drop_counts) }) + .collect(); + + let _ = std::panic::catch_unwind(move || { + let filter = |c: &mut Check| { + if c.index == 2 { + panic!("panic at index: {}", c.index); + } + // Verify that if the filter could panic again on another element + // that it would not cause a double panic and all elements of the + // vec would still be dropped exactly once. + if c.index == 4 { + panic!("panic at index: {}", c.index); + } + c.index < 6 + }; + let _drain = data.drain_filter(filter); + + // NOTE: The DrainFilter is dropped without being consumed + }); + + let drop_counts = drop_counts.lock().unwrap(); + assert_eq!(check_count, drop_counts.len()); + + for (index, count) in drop_counts.iter().cloned().enumerate() { + assert_eq!(1, count, "unexpected drop count at index: {} (count: {})", index, count); + } +} + +#[test] +fn drain_filter_unconsumed() { + let mut vec = vec![1, 2, 3, 4]; + let drain = vec.drain_filter(|&mut x| x % 2 != 0); + drop(drain); + assert_eq!(vec, [2, 4]); +} + +#[test] fn test_reserve_exact() { // This is all the same as test_reserve @@ -983,6 +1078,7 @@ fn test_reserve_exact() { } #[test] +#[cfg(not(miri))] // Miri does not support signalling OOM fn test_try_reserve() { // These are the interesting cases: @@ -1085,6 +1181,7 @@ fn test_try_reserve() { } #[test] +#[cfg(not(miri))] // Miri does not support signalling OOM fn test_try_reserve_exact() { // This is exactly the same as test_try_reserve with the method changed. @@ -1163,3 +1260,24 @@ fn test_try_reserve_exact() { } } + +#[test] +fn test_stable_push_pop() { + // Test that, if we reserved enough space, adding and removing elements does not + // invalidate references into the vector (such as `v0`). This test also + // runs in Miri, which would detect such problems. + let mut v = Vec::with_capacity(10); + v.push(13); + + // laundering the lifetime -- we take care that `v` does not reallocate, so that's okay. + let v0 = unsafe { &*(&v[0] as *const _) }; + + // Now do a bunch of things and occasionally use `v0` again to assert it is still valid. + v.push(1); + v.push(2); + v.insert(1, 1); + assert_eq!(*v0, 13); + v.remove(1); + v.pop().unwrap(); + assert_eq!(*v0, 13); +} diff --git a/src/liballoc/tests/vec_deque.rs b/src/liballoc/tests/vec_deque.rs index 16ddc1444fc..1bbcca97b3c 100644 --- a/src/liballoc/tests/vec_deque.rs +++ b/src/liballoc/tests/vec_deque.rs @@ -44,7 +44,6 @@ fn test_simple() { assert_eq!(d[3], 4); } -#[cfg(test)] fn test_parameterized<T: Clone + PartialEq + Debug>(a: T, b: T, c: T, d: T) { let mut deq = VecDeque::new(); assert_eq!(deq.len(), 0); @@ -108,7 +107,6 @@ fn test_index() { #[test] #[should_panic] -#[cfg(not(miri))] // Miri does not support panics fn test_index_out_of_bounds() { let mut deq = VecDeque::new(); for i in 1..4 { diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs index cd62c3e0524..dac04e4e624 100644 --- a/src/liballoc/vec.rs +++ b/src/liballoc/vec.rs @@ -56,6 +56,7 @@ #![stable(feature = "rust1", since = "1.0.0")] +use core::array::LengthAtMost32; use core::cmp::{self, Ordering}; use core::fmt; use core::hash::{self, Hash}; @@ -432,7 +433,7 @@ impl<T> Vec<T> { #[inline] #[stable(feature = "rust1", since = "1.0.0")] pub fn capacity(&self) -> usize { - self.buf.cap() + self.buf.capacity() } /// Reserves capacity for at least `additional` more elements to be inserted @@ -735,6 +736,75 @@ impl<T> Vec<T> { self } + /// Returns a raw pointer to the vector's buffer. + /// + /// The caller must ensure that the vector outlives the pointer this + /// function returns, or else it will end up pointing to garbage. + /// Modifying the vector may cause its buffer to be reallocated, + /// which would also make any pointers to it invalid. + /// + /// The caller must also ensure that the memory the pointer (non-transitively) points to + /// is never written to (except inside an `UnsafeCell`) using this pointer or any pointer + /// derived from it. If you need to mutate the contents of the slice, use [`as_mut_ptr`]. + /// + /// # Examples + /// + /// ``` + /// let x = vec![1, 2, 4]; + /// let x_ptr = x.as_ptr(); + /// + /// unsafe { + /// for i in 0..x.len() { + /// assert_eq!(*x_ptr.add(i), 1 << i); + /// } + /// } + /// ``` + /// + /// [`as_mut_ptr`]: #method.as_mut_ptr + #[stable(feature = "vec_as_ptr", since = "1.37.0")] + #[inline] + pub fn as_ptr(&self) -> *const T { + // We shadow the slice method of the same name to avoid going through + // `deref`, which creates an intermediate reference. + let ptr = self.buf.ptr(); + unsafe { assume(!ptr.is_null()); } + ptr + } + + /// Returns an unsafe mutable pointer to the vector's buffer. + /// + /// The caller must ensure that the vector outlives the pointer this + /// function returns, or else it will end up pointing to garbage. + /// Modifying the vector may cause its buffer to be reallocated, + /// which would also make any pointers to it invalid. + /// + /// # Examples + /// + /// ``` + /// // Allocate vector big enough for 4 elements. + /// let size = 4; + /// let mut x: Vec<i32> = Vec::with_capacity(size); + /// let x_ptr = x.as_mut_ptr(); + /// + /// // Initialize elements via raw pointer writes, then set length. + /// unsafe { + /// for i in 0..size { + /// *x_ptr.add(i) = i as i32; + /// } + /// x.set_len(size); + /// } + /// assert_eq!(&*x, &[0,1,2,3]); + /// ``` + #[stable(feature = "vec_as_ptr", since = "1.37.0")] + #[inline] + pub fn as_mut_ptr(&mut self) -> *mut T { + // We shadow the slice method of the same name to avoid going through + // `deref_mut`, which creates an intermediate reference. + let ptr = self.buf.ptr(); + unsafe { assume(!ptr.is_null()); } + ptr + } + /// Forces the length of the vector to `new_len`. /// /// This is a low-level operation that maintains none of the normal @@ -878,7 +948,7 @@ impl<T> Vec<T> { assert!(index <= len); // space for the new element - if len == self.buf.cap() { + if len == self.buf.capacity() { self.reserve(1); } @@ -937,8 +1007,8 @@ impl<T> Vec<T> { /// Retains only the elements specified by the predicate. /// /// In other words, remove all elements `e` such that `f(&e)` returns `false`. - /// This method operates in place and preserves the order of the retained - /// elements. + /// This method operates in place, visiting each element exactly once in the + /// original order, and preserves the order of the retained elements. /// /// # Examples /// @@ -947,6 +1017,16 @@ impl<T> Vec<T> { /// vec.retain(|&x| x%2 == 0); /// assert_eq!(vec, [2, 4]); /// ``` + /// + /// The exact order may be useful for tracking external state, like an index. + /// + /// ``` + /// let mut vec = vec![1, 2, 3, 4, 5]; + /// let keep = [false, true, true, false, true]; + /// let mut i = 0; + /// vec.retain(|_| (keep[i], i += 1).0); + /// assert_eq!(vec, [2, 3, 5]); + /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn retain<F>(&mut self, mut f: F) where F: FnMut(&T) -> bool @@ -1019,7 +1099,7 @@ impl<T> Vec<T> { pub fn push(&mut self, value: T) { // This will panic or abort if we would allocate > isize::MAX bytes // or if the length increment would overflow for zero-sized types. - if self.len == self.buf.cap() { + if self.len == self.buf.capacity() { self.reserve(1); } unsafe { @@ -1084,7 +1164,7 @@ impl<T> Vec<T> { let count = (*other).len(); self.reserve(count); let len = self.len(); - ptr::copy_nonoverlapping(other as *const T, self.get_unchecked_mut(len), count); + ptr::copy_nonoverlapping(other as *const T, self.as_mut_ptr().add(len), count); self.len += count; } @@ -1288,6 +1368,40 @@ impl<T> Vec<T> { self.truncate(new_len); } } + + /// Consumes and leaks the `Vec`, returning a mutable reference to the contents, + /// `&'a mut [T]`. Note that the type `T` must outlive the chosen lifetime + /// `'a`. If the type has only static references, or none at all, then this + /// may be chosen to be `'static`. + /// + /// This function is similar to the `leak` function on `Box`. + /// + /// This function is mainly useful for data that lives for the remainder of + /// the program's life. Dropping the returned reference will cause a memory + /// leak. + /// + /// # Examples + /// + /// Simple usage: + /// + /// ``` + /// #![feature(vec_leak)] + /// + /// fn main() { + /// let x = vec![1, 2, 3]; + /// let static_ref: &'static mut [usize] = Vec::leak(x); + /// static_ref[0] += 1; + /// assert_eq!(static_ref, &[2, 2, 3]); + /// } + /// ``` + #[unstable(feature = "vec_leak", issue = "62195")] + #[inline] + pub fn leak<'a>(vec: Vec<T>) -> &'a mut [T] + where + T: 'a // Technically not needed, but kept to be explicit. + { + Box::leak(vec.into_boxed_slice()) + } } impl<T: Clone> Vec<T> { @@ -1696,9 +1810,7 @@ impl<T> ops::Deref for Vec<T> { fn deref(&self) -> &[T] { unsafe { - let p = self.buf.ptr(); - assume(!p.is_null()); - slice::from_raw_parts(p, self.len) + slice::from_raw_parts(self.as_ptr(), self.len) } } } @@ -1707,9 +1819,7 @@ impl<T> ops::Deref for Vec<T> { impl<T> ops::DerefMut for Vec<T> { fn deref_mut(&mut self) -> &mut [T] { unsafe { - let ptr = self.buf.ptr(); - assume(!ptr.is_null()); - slice::from_raw_parts_mut(ptr, self.len) + slice::from_raw_parts_mut(self.as_mut_ptr(), self.len) } } } @@ -1744,13 +1854,12 @@ impl<T> IntoIterator for Vec<T> { fn into_iter(mut self) -> IntoIter<T> { unsafe { let begin = self.as_mut_ptr(); - assume(!begin.is_null()); let end = if mem::size_of::<T>() == 0 { arith_offset(begin as *const i8, self.len() as isize) as *const T } else { begin.add(self.len()) as *const T }; - let cap = self.buf.cap(); + let cap = self.buf.capacity(); mem::forget(self); IntoIter { buf: NonNull::new_unchecked(begin), @@ -1944,16 +2053,14 @@ impl<T> Vec<T> { /// with the given `replace_with` iterator and yields the removed items. /// `replace_with` does not need to be the same length as `range`. /// - /// Note 1: The element range is removed even if the iterator is not - /// consumed until the end. + /// The element range is removed even if the iterator is not consumed until the end. /// - /// Note 2: It is unspecified how many elements are removed from the vector, + /// It is unspecified how many elements are removed from the vector /// if the `Splice` value is leaked. /// - /// Note 3: The input iterator `replace_with` is only consumed - /// when the `Splice` value is dropped. + /// The input iterator `replace_with` is only consumed when the `Splice` value is dropped. /// - /// Note 4: This is optimal if: + /// This is optimal if: /// /// * The tail (elements in the vector after `range`) is empty, /// * or `replace_with` yields fewer elements than `range`’s length @@ -2046,6 +2153,7 @@ impl<T> Vec<T> { del: 0, old_len, pred: filter, + panic_flag: false, } } } @@ -2064,47 +2172,36 @@ impl<'a, T: 'a + Copy> Extend<&'a T> for Vec<T> { } macro_rules! __impl_slice_eq1 { - ($Lhs: ty, $Rhs: ty) => { - __impl_slice_eq1! { $Lhs, $Rhs, Sized } - }; - ($Lhs: ty, $Rhs: ty, $Bound: ident) => { + ([$($vars:tt)*] $lhs:ty, $rhs:ty, $($constraints:tt)*) => { #[stable(feature = "rust1", since = "1.0.0")] - impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> { + impl<A, B, $($vars)*> PartialEq<$rhs> for $lhs + where + A: PartialEq<B>, + $($constraints)* + { #[inline] - fn eq(&self, other: &$Rhs) -> bool { self[..] == other[..] } + fn eq(&self, other: &$rhs) -> bool { self[..] == other[..] } #[inline] - fn ne(&self, other: &$Rhs) -> bool { self[..] != other[..] } + fn ne(&self, other: &$rhs) -> bool { self[..] != other[..] } } } } -__impl_slice_eq1! { Vec<A>, Vec<B> } -__impl_slice_eq1! { Vec<A>, &'b [B] } -__impl_slice_eq1! { Vec<A>, &'b mut [B] } -__impl_slice_eq1! { Cow<'a, [A]>, &'b [B], Clone } -__impl_slice_eq1! { Cow<'a, [A]>, &'b mut [B], Clone } -__impl_slice_eq1! { Cow<'a, [A]>, Vec<B>, Clone } +__impl_slice_eq1! { [] Vec<A>, Vec<B>, } +__impl_slice_eq1! { [] Vec<A>, &[B], } +__impl_slice_eq1! { [] Vec<A>, &mut [B], } +__impl_slice_eq1! { [] Cow<'_, [A]>, &[B], A: Clone } +__impl_slice_eq1! { [] Cow<'_, [A]>, &mut [B], A: Clone } +__impl_slice_eq1! { [] Cow<'_, [A]>, Vec<B>, A: Clone } +__impl_slice_eq1! { [const N: usize] Vec<A>, [B; N], [B; N]: LengthAtMost32 } +__impl_slice_eq1! { [const N: usize] Vec<A>, &[B; N], [B; N]: LengthAtMost32 } -macro_rules! array_impls { - ($($N: expr)+) => { - $( - // NOTE: some less important impls are omitted to reduce code bloat - __impl_slice_eq1! { Vec<A>, [B; $N] } - __impl_slice_eq1! { Vec<A>, &'b [B; $N] } - // __impl_slice_eq1! { Vec<A>, &'b mut [B; $N] } - // __impl_slice_eq1! { Cow<'a, [A]>, [B; $N], Clone } - // __impl_slice_eq1! { Cow<'a, [A]>, &'b [B; $N], Clone } - // __impl_slice_eq1! { Cow<'a, [A]>, &'b mut [B; $N], Clone } - )+ - } -} - -array_impls! { - 0 1 2 3 4 5 6 7 8 9 - 10 11 12 13 14 15 16 17 18 19 - 20 21 22 23 24 25 26 27 28 29 - 30 31 32 -} +// NOTE: some less important impls are omitted to reduce code bloat +// FIXME(Centril): Reconsider this? +//__impl_slice_eq1! { [const N: usize] Vec<A>, &mut [B; N], [B; N]: LengthAtMost32 } +//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, [B; N], [B; N]: LengthAtMost32 } +//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, &[B; N], [B; N]: LengthAtMost32 } +//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, &mut [B; N], [B; N]: LengthAtMost32 } /// Implements comparison of vectors, lexicographically. #[stable(feature = "rust1", since = "1.0.0")] @@ -2673,10 +2770,20 @@ pub struct DrainFilter<'a, T, F> where F: FnMut(&mut T) -> bool, { vec: &'a mut Vec<T>, + /// The index of the item that will be inspected by the next call to `next`. idx: usize, + /// The number of items that have been drained (removed) thus far. del: usize, + /// The original length of `vec` prior to draining. old_len: usize, + /// The filter test predicate. pred: F, + /// A flag that indicates a panic has occured in the filter test prodicate. + /// This is used as a hint in the drop implmentation to prevent consumption + /// of the remainder of the `DrainFilter`. Any unprocessed items will be + /// backshifted in the `vec`, but no further items will be dropped or + /// tested by the filter predicate. + panic_flag: bool, } #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] @@ -2687,20 +2794,23 @@ impl<T, F> Iterator for DrainFilter<'_, T, F> fn next(&mut self) -> Option<T> { unsafe { - while self.idx != self.old_len { + while self.idx < self.old_len { let i = self.idx; - self.idx += 1; let v = slice::from_raw_parts_mut(self.vec.as_mut_ptr(), self.old_len); - if (self.pred)(&mut v[i]) { + self.panic_flag = true; + let drained = (self.pred)(&mut v[i]); + self.panic_flag = false; + // Update the index *after* the predicate is called. If the index + // is updated prior and the predicate panics, the element at this + // index would be leaked. + self.idx += 1; + if drained { self.del += 1; return Some(ptr::read(&v[i])); } else if self.del > 0 { let del = self.del; let src: *const T = &v[i]; let dst: *mut T = &mut v[i - del]; - // This is safe because self.vec has length 0 - // thus its elements will not have Drop::drop - // called on them in the event of a panic. ptr::copy_nonoverlapping(src, dst, 1); } } @@ -2718,9 +2828,46 @@ impl<T, F> Drop for DrainFilter<'_, T, F> where F: FnMut(&mut T) -> bool, { fn drop(&mut self) { - self.for_each(drop); - unsafe { - self.vec.set_len(self.old_len - self.del); + struct BackshiftOnDrop<'a, 'b, T, F> + where + F: FnMut(&mut T) -> bool, + { + drain: &'b mut DrainFilter<'a, T, F>, + } + + impl<'a, 'b, T, F> Drop for BackshiftOnDrop<'a, 'b, T, F> + where + F: FnMut(&mut T) -> bool + { + fn drop(&mut self) { + unsafe { + if self.drain.idx < self.drain.old_len && self.drain.del > 0 { + // This is a pretty messed up state, and there isn't really an + // obviously right thing to do. We don't want to keep trying + // to execute `pred`, so we just backshift all the unprocessed + // elements and tell the vec that they still exist. The backshift + // is required to prevent a double-drop of the last successfully + // drained item prior to a panic in the predicate. + let ptr = self.drain.vec.as_mut_ptr(); + let src = ptr.add(self.drain.idx); + let dst = src.sub(self.drain.del); + let tail_len = self.drain.old_len - self.drain.idx; + src.copy_to(dst, tail_len); + } + self.drain.vec.set_len(self.drain.old_len - self.drain.del); + } + } + } + + let backshift = BackshiftOnDrop { + drain: self + }; + + // Attempt to consume any remaining elements if the filter predicate + // has not yet panicked. We'll backshift any remaining elements + // whether we've already panicked or if the consumption here panics. + if !backshift.drain.panic_flag { + backshift.drain.for_each(drop); } } } |