diff options
Diffstat (limited to 'library/alloc/src/slice.rs')
| -rw-r--r-- | library/alloc/src/slice.rs | 182 |
1 files changed, 65 insertions, 117 deletions
diff --git a/library/alloc/src/slice.rs b/library/alloc/src/slice.rs index 8baf9685062..7c5d22e1ee9 100644 --- a/library/alloc/src/slice.rs +++ b/library/alloc/src/slice.rs @@ -8,9 +8,6 @@ //! A few functions are provided to create a slice from a value reference //! or from a raw pointer. #![stable(feature = "rust1", since = "1.0.0")] -// Many of the usings in this module are only used in the test configuration. -// It's cleaner to just turn off the unused_imports warning than to fix them. -#![cfg_attr(test, allow(unused_imports, dead_code))] use core::borrow::{Borrow, BorrowMut}; #[cfg(not(no_global_oom_handling))] @@ -63,16 +60,6 @@ pub use core::slice::{range, try_range}; //////////////////////////////////////////////////////////////////////////////// // Basic slice extension methods //////////////////////////////////////////////////////////////////////////////// - -// HACK(japaric) needed for the implementation of `vec!` macro during testing -// 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 -// N.B., see the `hack` module in this file for more details. -#[cfg(test)] -pub use hack::to_vec; - use crate::alloc::Allocator; #[cfg(not(no_global_oom_handling))] use crate::alloc::Global; @@ -81,98 +68,6 @@ use crate::borrow::ToOwned; use crate::boxed::Box; use crate::vec::Vec; -// HACK(japaric): With cfg(test) `impl [T]` is not available, these three -// functions are actually methods that are in `impl [T]` but not in -// `core::slice::SliceExt` - we need to supply these functions for the -// `test_permutations` test -#[allow(unreachable_pub)] // cfg(test) pub above -pub(crate) mod hack { - use core::alloc::Allocator; - - use crate::boxed::Box; - use crate::vec::Vec; - - // We shouldn't add inline attribute to this since this is used in - // `vec!` macro mostly and causes perf regression. See #71204 for - // discussion and perf results. - #[allow(missing_docs)] - pub fn into_vec<T, A: Allocator>(b: Box<[T], A>) -> Vec<T, A> { - unsafe { - let len = b.len(); - let (b, alloc) = Box::into_raw_with_allocator(b); - Vec::from_raw_parts_in(b as *mut T, len, len, alloc) - } - } - - #[cfg(not(no_global_oom_handling))] - #[allow(missing_docs)] - #[inline] - pub fn to_vec<T: ConvertVec, A: Allocator>(s: &[T], alloc: A) -> Vec<T, A> { - T::to_vec(s, alloc) - } - - #[cfg(not(no_global_oom_handling))] - pub trait ConvertVec { - fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> - where - Self: Sized; - } - - #[cfg(not(no_global_oom_handling))] - impl<T: Clone> ConvertVec for T { - #[inline] - default fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> { - struct DropGuard<'a, T, A: Allocator> { - vec: &'a mut Vec<T, A>, - num_init: usize, - } - impl<'a, T, A: Allocator> Drop for DropGuard<'a, T, A> { - #[inline] - fn drop(&mut self) { - // SAFETY: - // items were marked initialized in the loop below - unsafe { - self.vec.set_len(self.num_init); - } - } - } - let mut vec = Vec::with_capacity_in(s.len(), alloc); - let mut guard = DropGuard { vec: &mut vec, num_init: 0 }; - let slots = guard.vec.spare_capacity_mut(); - // .take(slots.len()) is necessary for LLVM to remove bounds checks - // and has better codegen than zip. - for (i, b) in s.iter().enumerate().take(slots.len()) { - guard.num_init = i; - slots[i].write(b.clone()); - } - core::mem::forget(guard); - // SAFETY: - // the vec was allocated and initialized above to at least this length. - unsafe { - vec.set_len(s.len()); - } - vec - } - } - - #[cfg(not(no_global_oom_handling))] - impl<T: Copy> ConvertVec for T { - #[inline] - fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> { - let mut v = Vec::with_capacity_in(s.len(), alloc); - // SAFETY: - // allocated above with the capacity of `s`, and initialize to `s.len()` in - // ptr::copy_to_non_overlapping below. - unsafe { - s.as_ptr().copy_to_nonoverlapping(v.as_mut_ptr(), s.len()); - v.set_len(s.len()); - } - v - } - } -} - -#[cfg(not(test))] impl<T> [T] { /// Sorts the slice, preserving initial order of equal elements. /// @@ -501,8 +396,64 @@ impl<T> [T] { where T: Clone, { - // N.B., see the `hack` module in this file for more details. - hack::to_vec(self, alloc) + return T::to_vec(self, alloc); + + trait ConvertVec { + fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> + where + Self: Sized; + } + + impl<T: Clone> ConvertVec for T { + #[inline] + default fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> { + struct DropGuard<'a, T, A: Allocator> { + vec: &'a mut Vec<T, A>, + num_init: usize, + } + impl<'a, T, A: Allocator> Drop for DropGuard<'a, T, A> { + #[inline] + fn drop(&mut self) { + // SAFETY: + // items were marked initialized in the loop below + unsafe { + self.vec.set_len(self.num_init); + } + } + } + let mut vec = Vec::with_capacity_in(s.len(), alloc); + let mut guard = DropGuard { vec: &mut vec, num_init: 0 }; + let slots = guard.vec.spare_capacity_mut(); + // .take(slots.len()) is necessary for LLVM to remove bounds checks + // and has better codegen than zip. + for (i, b) in s.iter().enumerate().take(slots.len()) { + guard.num_init = i; + slots[i].write(b.clone()); + } + core::mem::forget(guard); + // SAFETY: + // the vec was allocated and initialized above to at least this length. + unsafe { + vec.set_len(s.len()); + } + vec + } + } + + impl<T: Copy> ConvertVec for T { + #[inline] + fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> { + let mut v = Vec::with_capacity_in(s.len(), alloc); + // SAFETY: + // allocated above with the capacity of `s`, and initialize to `s.len()` in + // ptr::copy_to_non_overlapping below. + unsafe { + s.as_ptr().copy_to_nonoverlapping(v.as_mut_ptr(), s.len()); + v.set_len(s.len()); + } + v + } + } } /// Converts `self` into a vector without clones or allocation. @@ -522,10 +473,13 @@ impl<T> [T] { #[rustc_allow_incoherent_impl] #[stable(feature = "rust1", since = "1.0.0")] #[inline] - #[cfg_attr(not(test), rustc_diagnostic_item = "slice_into_vec")] + #[rustc_diagnostic_item = "slice_into_vec"] pub fn into_vec<A: Allocator>(self: Box<Self, A>) -> Vec<T, A> { - // N.B., see the `hack` module in this file for more details. - hack::into_vec(self) + unsafe { + let len = self.len(); + let (b, alloc) = Box::into_raw_with_allocator(self); + Vec::from_raw_parts_in(b as *mut T, len, len, alloc) + } } /// Creates a vector by copying a slice `n` times. @@ -666,7 +620,6 @@ impl<T> [T] { } } -#[cfg(not(test))] impl [u8] { /// Returns a vector containing a copy of this slice where each byte /// is mapped to its ASCII upper case equivalent. @@ -883,14 +836,9 @@ impl<T: Copy, A: Allocator> SpecCloneIntoVec<T, A> for [T] { #[stable(feature = "rust1", since = "1.0.0")] impl<T: Clone> ToOwned for [T] { type Owned = Vec<T>; - #[cfg(not(test))] - fn to_owned(&self) -> Vec<T> { - self.to_vec() - } - #[cfg(test)] fn to_owned(&self) -> Vec<T> { - hack::to_vec(self, Global) + self.to_vec() } fn clone_into(&self, target: &mut Vec<T>) { |