From 114d5f221c135e3267fbb966e2f0e582361cd8cb Mon Sep 17 00:00:00 2001 From: The 8472 Date: Sun, 9 Apr 2023 00:37:21 +0200 Subject: s/drain_filter/extract_if/ for Vec, Btree{Map,Set} and LinkedList --- library/alloc/benches/btree/map.rs | 12 +- library/alloc/benches/btree/set.rs | 8 +- library/alloc/benches/lib.rs | 2 +- library/alloc/src/collections/btree/map.rs | 56 +++++----- library/alloc/src/collections/btree/map/tests.rs | 56 +++++----- library/alloc/src/collections/btree/set.rs | 41 ++++--- library/alloc/src/collections/btree/set/tests.rs | 26 ++--- library/alloc/src/collections/linked_list.rs | 32 +++--- library/alloc/src/collections/linked_list/tests.rs | 42 +++---- library/alloc/src/vec/drain_filter.rs | 121 --------------------- library/alloc/src/vec/extract_if.rs | 121 +++++++++++++++++++++ library/alloc/src/vec/mod.rs | 22 ++-- library/alloc/tests/autotraits.rs | 6 +- library/alloc/tests/lib.rs | 4 +- library/alloc/tests/vec.rs | 44 ++++---- 15 files changed, 294 insertions(+), 299 deletions(-) delete mode 100644 library/alloc/src/vec/drain_filter.rs create mode 100644 library/alloc/src/vec/extract_if.rs (limited to 'library/alloc') diff --git a/library/alloc/benches/btree/map.rs b/library/alloc/benches/btree/map.rs index ec1b0a8eba0..7d236647750 100644 --- a/library/alloc/benches/btree/map.rs +++ b/library/alloc/benches/btree/map.rs @@ -385,7 +385,7 @@ pub fn clone_slim_100_and_clear(b: &mut Bencher) { #[bench] pub fn clone_slim_100_and_drain_all(b: &mut Bencher) { let src = slim_map(100); - b.iter(|| src.clone().drain_filter(|_, _| true).count()) + b.iter(|| src.clone().extract_if(|_, _| true).count()) } #[bench] @@ -393,7 +393,7 @@ pub fn clone_slim_100_and_drain_half(b: &mut Bencher) { let src = slim_map(100); b.iter(|| { let mut map = src.clone(); - assert_eq!(map.drain_filter(|i, _| i % 2 == 0).count(), 100 / 2); + assert_eq!(map.extract_if(|i, _| i % 2 == 0).count(), 100 / 2); assert_eq!(map.len(), 100 / 2); }) } @@ -456,7 +456,7 @@ pub fn clone_slim_10k_and_clear(b: &mut Bencher) { #[bench] pub fn clone_slim_10k_and_drain_all(b: &mut Bencher) { let src = slim_map(10_000); - b.iter(|| src.clone().drain_filter(|_, _| true).count()) + b.iter(|| src.clone().extract_if(|_, _| true).count()) } #[bench] @@ -464,7 +464,7 @@ pub fn clone_slim_10k_and_drain_half(b: &mut Bencher) { let src = slim_map(10_000); b.iter(|| { let mut map = src.clone(); - assert_eq!(map.drain_filter(|i, _| i % 2 == 0).count(), 10_000 / 2); + assert_eq!(map.extract_if(|i, _| i % 2 == 0).count(), 10_000 / 2); assert_eq!(map.len(), 10_000 / 2); }) } @@ -527,7 +527,7 @@ pub fn clone_fat_val_100_and_clear(b: &mut Bencher) { #[bench] pub fn clone_fat_val_100_and_drain_all(b: &mut Bencher) { let src = fat_val_map(100); - b.iter(|| src.clone().drain_filter(|_, _| true).count()) + b.iter(|| src.clone().extract_if(|_, _| true).count()) } #[bench] @@ -535,7 +535,7 @@ pub fn clone_fat_val_100_and_drain_half(b: &mut Bencher) { let src = fat_val_map(100); b.iter(|| { let mut map = src.clone(); - assert_eq!(map.drain_filter(|i, _| i % 2 == 0).count(), 100 / 2); + assert_eq!(map.extract_if(|i, _| i % 2 == 0).count(), 100 / 2); assert_eq!(map.len(), 100 / 2); }) } diff --git a/library/alloc/benches/btree/set.rs b/library/alloc/benches/btree/set.rs index 3f4b0e0f14a..09d72c72064 100644 --- a/library/alloc/benches/btree/set.rs +++ b/library/alloc/benches/btree/set.rs @@ -69,7 +69,7 @@ pub fn clone_100_and_clear(b: &mut Bencher) { #[bench] pub fn clone_100_and_drain_all(b: &mut Bencher) { let src = slim_set(100); - b.iter(|| src.clone().drain_filter(|_| true).count()) + b.iter(|| src.clone().extract_if(|_| true).count()) } #[bench] @@ -77,7 +77,7 @@ pub fn clone_100_and_drain_half(b: &mut Bencher) { let src = slim_set(100); b.iter(|| { let mut set = src.clone(); - assert_eq!(set.drain_filter(|i| i % 2 == 0).count(), 100 / 2); + assert_eq!(set.extract_if(|i| i % 2 == 0).count(), 100 / 2); assert_eq!(set.len(), 100 / 2); }) } @@ -140,7 +140,7 @@ pub fn clone_10k_and_clear(b: &mut Bencher) { #[bench] pub fn clone_10k_and_drain_all(b: &mut Bencher) { let src = slim_set(10_000); - b.iter(|| src.clone().drain_filter(|_| true).count()) + b.iter(|| src.clone().extract_if(|_| true).count()) } #[bench] @@ -148,7 +148,7 @@ pub fn clone_10k_and_drain_half(b: &mut Bencher) { let src = slim_set(10_000); b.iter(|| { let mut set = src.clone(); - assert_eq!(set.drain_filter(|i| i % 2 == 0).count(), 10_000 / 2); + assert_eq!(set.extract_if(|i| i % 2 == 0).count(), 10_000 / 2); assert_eq!(set.len(), 10_000 / 2); }) } diff --git a/library/alloc/benches/lib.rs b/library/alloc/benches/lib.rs index b25d63d835b..638f343fb24 100644 --- a/library/alloc/benches/lib.rs +++ b/library/alloc/benches/lib.rs @@ -1,7 +1,7 @@ // Disabling on android for the time being // See https://github.com/rust-lang/rust/issues/73535#event-3477699747 #![cfg(not(target_os = "android"))] -#![feature(btree_drain_filter)] +#![feature(btree_extract_if)] #![feature(iter_next_chunk)] #![feature(repr_simd)] #![feature(slice_partition_dedup)] diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs index 4f50cdefc3c..ff908ec12ec 100644 --- a/library/alloc/src/collections/btree/map.rs +++ b/library/alloc/src/collections/btree/map.rs @@ -1132,7 +1132,7 @@ impl BTreeMap { K: Ord, F: FnMut(&K, &mut V) -> bool, { - self.drain_filter(|k, v| !f(k, v)).for_each(drop); + self.extract_if(|k, v| !f(k, v)).for_each(drop); } /// Moves all elements from `other` into `self`, leaving `other` empty. @@ -1395,7 +1395,7 @@ impl BTreeMap { /// The iterator also lets you mutate the value of each element in the /// closure, regardless of whether you choose to keep or remove it. /// - /// If the returned `DrainFilter` is not exhausted, e.g. because it is dropped without iterating + /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating /// or the iteration short-circuits, then the remaining elements will be retained. /// Use [`retain`] with a negated predicate if you do not need the returned iterator. /// @@ -1406,26 +1406,26 @@ impl BTreeMap { /// Splitting a map into even and odd keys, reusing the original map: /// /// ``` - /// #![feature(btree_drain_filter)] + /// #![feature(btree_extract_if)] /// use std::collections::BTreeMap; /// /// let mut map: BTreeMap = (0..8).map(|x| (x, x)).collect(); - /// let evens: BTreeMap<_, _> = map.drain_filter(|k, _v| k % 2 == 0).collect(); + /// let evens: BTreeMap<_, _> = map.extract_if(|k, _v| k % 2 == 0).collect(); /// let odds = map; /// assert_eq!(evens.keys().copied().collect::>(), [0, 2, 4, 6]); /// assert_eq!(odds.keys().copied().collect::>(), [1, 3, 5, 7]); /// ``` - #[unstable(feature = "btree_drain_filter", issue = "70530")] - pub fn drain_filter(&mut self, pred: F) -> DrainFilter<'_, K, V, F, A> + #[unstable(feature = "btree_extract_if", issue = "70530")] + pub fn extract_if(&mut self, pred: F) -> ExtractIf<'_, K, V, F, A> where K: Ord, F: FnMut(&K, &mut V) -> bool, { - let (inner, alloc) = self.drain_filter_inner(); - DrainFilter { pred, inner, alloc } + let (inner, alloc) = self.extract_if_inner(); + ExtractIf { pred, inner, alloc } } - pub(super) fn drain_filter_inner(&mut self) -> (DrainFilterInner<'_, K, V>, A) + pub(super) fn extract_if_inner(&mut self) -> (ExtractIfInner<'_, K, V>, A) where K: Ord, { @@ -1433,7 +1433,7 @@ impl BTreeMap { let (root, dormant_root) = DormantMutRef::new(root); let front = root.borrow_mut().first_leaf_edge(); ( - DrainFilterInner { + ExtractIfInner { length: &mut self.length, dormant_root: Some(dormant_root), cur_leaf_edge: Some(front), @@ -1442,7 +1442,7 @@ impl BTreeMap { ) } else { ( - DrainFilterInner { + ExtractIfInner { length: &mut self.length, dormant_root: None, cur_leaf_edge: None, @@ -1896,10 +1896,10 @@ impl Default for Values<'_, K, V> { } } -/// An iterator produced by calling `drain_filter` on BTreeMap. -#[unstable(feature = "btree_drain_filter", issue = "70530")] +/// An iterator produced by calling `extract_if` on BTreeMap. +#[unstable(feature = "btree_extract_if", issue = "70530")] #[must_use = "iterators are lazy and do nothing unless consumed"] -pub struct DrainFilter< +pub struct ExtractIf< 'a, K, V, @@ -1909,13 +1909,13 @@ pub struct DrainFilter< F: 'a + FnMut(&K, &mut V) -> bool, { pred: F, - inner: DrainFilterInner<'a, K, V>, + inner: ExtractIfInner<'a, K, V>, /// The BTreeMap will outlive this IntoIter so we don't care about drop order for `alloc`. alloc: A, } -/// Most of the implementation of DrainFilter are generic over the type -/// of the predicate, thus also serving for BTreeSet::DrainFilter. -pub(super) struct DrainFilterInner<'a, K, V> { +/// Most of the implementation of ExtractIf are generic over the type +/// of the predicate, thus also serving for BTreeSet::ExtractIf. +pub(super) struct ExtractIfInner<'a, K, V> { /// Reference to the length field in the borrowed map, updated live. length: &'a mut usize, /// Buried reference to the root field in the borrowed map. @@ -1927,20 +1927,20 @@ pub(super) struct DrainFilterInner<'a, K, V> { cur_leaf_edge: Option, K, V, marker::Leaf>, marker::Edge>>, } -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl fmt::Debug for DrainFilter<'_, K, V, F> +#[unstable(feature = "btree_extract_if", issue = "70530")] +impl fmt::Debug for ExtractIf<'_, K, V, F> where K: fmt::Debug, V: fmt::Debug, F: FnMut(&K, &mut V) -> bool, { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("DrainFilter").field(&self.inner.peek()).finish() + f.debug_tuple("ExtractIf").field(&self.inner.peek()).finish() } } -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl Iterator for DrainFilter<'_, K, V, F, A> +#[unstable(feature = "btree_extract_if", issue = "70530")] +impl Iterator for ExtractIf<'_, K, V, F, A> where F: FnMut(&K, &mut V) -> bool, { @@ -1955,14 +1955,14 @@ where } } -impl<'a, K, V> DrainFilterInner<'a, K, V> { +impl<'a, K, V> ExtractIfInner<'a, K, V> { /// Allow Debug implementations to predict the next element. pub(super) fn peek(&self) -> Option<(&K, &V)> { let edge = self.cur_leaf_edge.as_ref()?; edge.reborrow().next_kv().ok().map(Handle::into_kv) } - /// Implementation of a typical `DrainFilter::next` method, given the predicate. + /// Implementation of a typical `ExtractIf::next` method, given the predicate. pub(super) fn next(&mut self, pred: &mut F, alloc: A) -> Option<(K, V)> where F: FnMut(&K, &mut V) -> bool, @@ -1989,7 +1989,7 @@ impl<'a, K, V> DrainFilterInner<'a, K, V> { None } - /// Implementation of a typical `DrainFilter::size_hint` method. + /// Implementation of a typical `ExtractIf::size_hint` method. pub(super) fn size_hint(&self) -> (usize, Option) { // In most of the btree iterators, `self.length` is the number of elements // yet to be visited. Here, it includes elements that were visited and that @@ -1999,8 +1999,8 @@ impl<'a, K, V> DrainFilterInner<'a, K, V> { } } -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl FusedIterator for DrainFilter<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {} +#[unstable(feature = "btree_extract_if", issue = "70530")] +impl FusedIterator for ExtractIf<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {} #[stable(feature = "btree_range", since = "1.17.0")] impl<'a, K, V> Iterator for Range<'a, K, V> { diff --git a/library/alloc/src/collections/btree/map/tests.rs b/library/alloc/src/collections/btree/map/tests.rs index 1b9957fcd51..8681cfcd617 100644 --- a/library/alloc/src/collections/btree/map/tests.rs +++ b/library/alloc/src/collections/btree/map/tests.rs @@ -941,13 +941,13 @@ fn test_retain() { assert_eq!(map[&6], 60); } -mod test_drain_filter { +mod test_extract_if { use super::*; #[test] fn empty() { let mut map: BTreeMap = BTreeMap::new(); - map.drain_filter(|_, _| unreachable!("there's nothing to decide on")).for_each(drop); + map.extract_if(|_, _| unreachable!("there's nothing to decide on")).for_each(drop); assert_eq!(map.height(), None); map.check(); } @@ -957,7 +957,7 @@ mod test_drain_filter { fn consumed_keeping_all() { let pairs = (0..3).map(|i| (i, i)); let mut map = BTreeMap::from_iter(pairs); - assert!(map.drain_filter(|_, _| false).eq(iter::empty())); + assert!(map.extract_if(|_, _| false).eq(iter::empty())); map.check(); } @@ -966,7 +966,7 @@ mod test_drain_filter { fn consumed_removing_all() { let pairs = (0..3).map(|i| (i, i)); let mut map = BTreeMap::from_iter(pairs.clone()); - assert!(map.drain_filter(|_, _| true).eq(pairs)); + assert!(map.extract_if(|_, _| true).eq(pairs)); assert!(map.is_empty()); map.check(); } @@ -977,7 +977,7 @@ mod test_drain_filter { let pairs = (0..3).map(|i| (i, i)); let mut map = BTreeMap::from_iter(pairs); assert!( - map.drain_filter(|_, v| { + map.extract_if(|_, v| { *v += 6; false }) @@ -994,7 +994,7 @@ mod test_drain_filter { let pairs = (0..3).map(|i| (i, i)); let mut map = BTreeMap::from_iter(pairs); assert!( - map.drain_filter(|_, v| { + map.extract_if(|_, v| { *v += 6; true }) @@ -1008,7 +1008,7 @@ mod test_drain_filter { fn underfull_keeping_all() { let pairs = (0..3).map(|i| (i, i)); let mut map = BTreeMap::from_iter(pairs); - map.drain_filter(|_, _| false).for_each(drop); + map.extract_if(|_, _| false).for_each(drop); assert!(map.keys().copied().eq(0..3)); map.check(); } @@ -1018,7 +1018,7 @@ mod test_drain_filter { let pairs = (0..3).map(|i| (i, i)); for doomed in 0..3 { let mut map = BTreeMap::from_iter(pairs.clone()); - map.drain_filter(|i, _| *i == doomed).for_each(drop); + map.extract_if(|i, _| *i == doomed).for_each(drop); assert_eq!(map.len(), 2); map.check(); } @@ -1029,7 +1029,7 @@ mod test_drain_filter { let pairs = (0..3).map(|i| (i, i)); for sacred in 0..3 { let mut map = BTreeMap::from_iter(pairs.clone()); - map.drain_filter(|i, _| *i != sacred).for_each(drop); + map.extract_if(|i, _| *i != sacred).for_each(drop); assert!(map.keys().copied().eq(sacred..=sacred)); map.check(); } @@ -1039,7 +1039,7 @@ mod test_drain_filter { fn underfull_removing_all() { let pairs = (0..3).map(|i| (i, i)); let mut map = BTreeMap::from_iter(pairs); - map.drain_filter(|_, _| true).for_each(drop); + map.extract_if(|_, _| true).for_each(drop); assert!(map.is_empty()); map.check(); } @@ -1048,7 +1048,7 @@ mod test_drain_filter { fn height_0_keeping_all() { let pairs = (0..node::CAPACITY).map(|i| (i, i)); let mut map = BTreeMap::from_iter(pairs); - map.drain_filter(|_, _| false).for_each(drop); + map.extract_if(|_, _| false).for_each(drop); assert!(map.keys().copied().eq(0..node::CAPACITY)); map.check(); } @@ -1058,7 +1058,7 @@ mod test_drain_filter { let pairs = (0..node::CAPACITY).map(|i| (i, i)); for doomed in 0..node::CAPACITY { let mut map = BTreeMap::from_iter(pairs.clone()); - map.drain_filter(|i, _| *i == doomed).for_each(drop); + map.extract_if(|i, _| *i == doomed).for_each(drop); assert_eq!(map.len(), node::CAPACITY - 1); map.check(); } @@ -1069,7 +1069,7 @@ mod test_drain_filter { let pairs = (0..node::CAPACITY).map(|i| (i, i)); for sacred in 0..node::CAPACITY { let mut map = BTreeMap::from_iter(pairs.clone()); - map.drain_filter(|i, _| *i != sacred).for_each(drop); + map.extract_if(|i, _| *i != sacred).for_each(drop); assert!(map.keys().copied().eq(sacred..=sacred)); map.check(); } @@ -1079,7 +1079,7 @@ mod test_drain_filter { fn height_0_removing_all() { let pairs = (0..node::CAPACITY).map(|i| (i, i)); let mut map = BTreeMap::from_iter(pairs); - map.drain_filter(|_, _| true).for_each(drop); + map.extract_if(|_, _| true).for_each(drop); assert!(map.is_empty()); map.check(); } @@ -1087,7 +1087,7 @@ mod test_drain_filter { #[test] fn height_0_keeping_half() { let mut map = BTreeMap::from_iter((0..16).map(|i| (i, i))); - assert_eq!(map.drain_filter(|i, _| *i % 2 == 0).count(), 8); + assert_eq!(map.extract_if(|i, _| *i % 2 == 0).count(), 8); assert_eq!(map.len(), 8); map.check(); } @@ -1096,7 +1096,7 @@ mod test_drain_filter { fn height_1_removing_all() { let pairs = (0..MIN_INSERTS_HEIGHT_1).map(|i| (i, i)); let mut map = BTreeMap::from_iter(pairs); - map.drain_filter(|_, _| true).for_each(drop); + map.extract_if(|_, _| true).for_each(drop); assert!(map.is_empty()); map.check(); } @@ -1106,7 +1106,7 @@ mod test_drain_filter { let pairs = (0..MIN_INSERTS_HEIGHT_1).map(|i| (i, i)); for doomed in 0..MIN_INSERTS_HEIGHT_1 { let mut map = BTreeMap::from_iter(pairs.clone()); - map.drain_filter(|i, _| *i == doomed).for_each(drop); + map.extract_if(|i, _| *i == doomed).for_each(drop); assert_eq!(map.len(), MIN_INSERTS_HEIGHT_1 - 1); map.check(); } @@ -1117,7 +1117,7 @@ mod test_drain_filter { let pairs = (0..MIN_INSERTS_HEIGHT_1).map(|i| (i, i)); for sacred in 0..MIN_INSERTS_HEIGHT_1 { let mut map = BTreeMap::from_iter(pairs.clone()); - map.drain_filter(|i, _| *i != sacred).for_each(drop); + map.extract_if(|i, _| *i != sacred).for_each(drop); assert!(map.keys().copied().eq(sacred..=sacred)); map.check(); } @@ -1128,7 +1128,7 @@ mod test_drain_filter { let pairs = (0..MIN_INSERTS_HEIGHT_2).map(|i| (i, i)); for doomed in (0..MIN_INSERTS_HEIGHT_2).step_by(12) { let mut map = BTreeMap::from_iter(pairs.clone()); - map.drain_filter(|i, _| *i == doomed).for_each(drop); + map.extract_if(|i, _| *i == doomed).for_each(drop); assert_eq!(map.len(), MIN_INSERTS_HEIGHT_2 - 1); map.check(); } @@ -1139,7 +1139,7 @@ mod test_drain_filter { let pairs = (0..MIN_INSERTS_HEIGHT_2).map(|i| (i, i)); for sacred in (0..MIN_INSERTS_HEIGHT_2).step_by(12) { let mut map = BTreeMap::from_iter(pairs.clone()); - map.drain_filter(|i, _| *i != sacred).for_each(drop); + map.extract_if(|i, _| *i != sacred).for_each(drop); assert!(map.keys().copied().eq(sacred..=sacred)); map.check(); } @@ -1149,7 +1149,7 @@ mod test_drain_filter { fn height_2_removing_all() { let pairs = (0..MIN_INSERTS_HEIGHT_2).map(|i| (i, i)); let mut map = BTreeMap::from_iter(pairs); - map.drain_filter(|_, _| true).for_each(drop); + map.extract_if(|_, _| true).for_each(drop); assert!(map.is_empty()); map.check(); } @@ -1165,7 +1165,7 @@ mod test_drain_filter { map.insert(b.spawn(Panic::InDrop), ()); map.insert(c.spawn(Panic::Never), ()); - catch_unwind(move || map.drain_filter(|dummy, _| dummy.query(true)).for_each(drop)) + catch_unwind(move || map.extract_if(|dummy, _| dummy.query(true)).for_each(drop)) .unwrap_err(); assert_eq!(a.queried(), 1); @@ -1188,7 +1188,7 @@ mod test_drain_filter { map.insert(c.spawn(Panic::InQuery), ()); catch_unwind(AssertUnwindSafe(|| { - map.drain_filter(|dummy, _| dummy.query(true)).for_each(drop) + map.extract_if(|dummy, _| dummy.query(true)).for_each(drop) })) .unwrap_err(); @@ -1217,7 +1217,7 @@ mod test_drain_filter { map.insert(c.spawn(Panic::InQuery), ()); { - let mut it = map.drain_filter(|dummy, _| dummy.query(true)); + let mut it = map.extract_if(|dummy, _| dummy.query(true)); catch_unwind(AssertUnwindSafe(|| while it.next().is_some() {})).unwrap_err(); // Iterator behaviour after a panic is explicitly unspecified, // so this is just the current implementation: @@ -1660,8 +1660,8 @@ fn assert_sync() { v.into_values() } - fn drain_filter(v: &mut BTreeMap) -> impl Sync + '_ { - v.drain_filter(|_, _| false) + fn extract_if(v: &mut BTreeMap) -> impl Sync + '_ { + v.extract_if(|_, _| false) } fn iter(v: &BTreeMap) -> impl Sync + '_ { @@ -1729,8 +1729,8 @@ fn assert_send() { v.into_values() } - fn drain_filter(v: &mut BTreeMap) -> impl Send + '_ { - v.drain_filter(|_, _| false) + fn extract_if(v: &mut BTreeMap) -> impl Send + '_ { + v.extract_if(|_, _| false) } fn iter(v: &BTreeMap) -> impl Send + '_ { diff --git a/library/alloc/src/collections/btree/set.rs b/library/alloc/src/collections/btree/set.rs index d8f34a7fa48..c4461040b20 100644 --- a/library/alloc/src/collections/btree/set.rs +++ b/library/alloc/src/collections/btree/set.rs @@ -999,7 +999,7 @@ impl BTreeSet { T: Ord, F: FnMut(&T) -> bool, { - self.drain_filter(|v| !f(v)).for_each(drop); + self.extract_if(|v| !f(v)).for_each(drop); } /// Moves all elements from `other` into `self`, leaving `other` empty. @@ -1084,7 +1084,7 @@ impl BTreeSet { /// yielded. If the closure returns `false`, or panics, the element remains /// in the set and will not be yielded. /// - /// If the returned `DrainFilter` is not exhausted, e.g. because it is dropped without iterating + /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating /// or the iteration short-circuits, then the remaining elements will be retained. /// Use [`retain`] with a negated predicate if you do not need the returned iterator. /// @@ -1094,23 +1094,23 @@ impl BTreeSet { /// Splitting a set into even and odd values, reusing the original set: /// /// ``` - /// #![feature(btree_drain_filter)] + /// #![feature(btree_extract_if)] /// use std::collections::BTreeSet; /// /// let mut set: BTreeSet = (0..8).collect(); - /// let evens: BTreeSet<_> = set.drain_filter(|v| v % 2 == 0).collect(); + /// let evens: BTreeSet<_> = set.extract_if(|v| v % 2 == 0).collect(); /// let odds = set; /// assert_eq!(evens.into_iter().collect::>(), vec![0, 2, 4, 6]); /// assert_eq!(odds.into_iter().collect::>(), vec![1, 3, 5, 7]); /// ``` - #[unstable(feature = "btree_drain_filter", issue = "70530")] - pub fn drain_filter<'a, F>(&'a mut self, pred: F) -> DrainFilter<'a, T, F, A> + #[unstable(feature = "btree_extract_if", issue = "70530")] + pub fn extract_if<'a, F>(&'a mut self, pred: F) -> ExtractIf<'a, T, F, A> where T: Ord, F: 'a + FnMut(&T) -> bool, { - let (inner, alloc) = self.map.drain_filter_inner(); - DrainFilter { pred, inner, alloc } + let (inner, alloc) = self.map.extract_if_inner(); + ExtractIf { pred, inner, alloc } } /// Gets an iterator that visits the elements in the `BTreeSet` in ascending @@ -1272,10 +1272,10 @@ impl<'a, T, A: Allocator + Clone> IntoIterator for &'a BTreeSet { } } -/// An iterator produced by calling `drain_filter` on BTreeSet. -#[unstable(feature = "btree_drain_filter", issue = "70530")] +/// An iterator produced by calling `extract_if` on BTreeSet. +#[unstable(feature = "btree_extract_if", issue = "70530")] #[must_use = "iterators are lazy and do nothing unless consumed"] -pub struct DrainFilter< +pub struct ExtractIf< 'a, T, F, @@ -1285,24 +1285,24 @@ pub struct DrainFilter< F: 'a + FnMut(&T) -> bool, { pred: F, - inner: super::map::DrainFilterInner<'a, T, SetValZST>, + inner: super::map::ExtractIfInner<'a, T, SetValZST>, /// The BTreeMap will outlive this IntoIter so we don't care about drop order for `alloc`. alloc: A, } -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl fmt::Debug for DrainFilter<'_, T, F, A> +#[unstable(feature = "btree_extract_if", issue = "70530")] +impl fmt::Debug for ExtractIf<'_, T, F, A> where T: fmt::Debug, F: FnMut(&T) -> bool, { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("DrainFilter").field(&self.inner.peek().map(|(k, _)| k)).finish() + f.debug_tuple("ExtractIf").field(&self.inner.peek().map(|(k, _)| k)).finish() } } -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl<'a, T, F, A: Allocator + Clone> Iterator for DrainFilter<'_, T, F, A> +#[unstable(feature = "btree_extract_if", issue = "70530")] +impl<'a, T, F, A: Allocator + Clone> Iterator for ExtractIf<'_, T, F, A> where F: 'a + FnMut(&T) -> bool, { @@ -1319,11 +1319,8 @@ where } } -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl FusedIterator for DrainFilter<'_, T, F, A> where - F: FnMut(&T) -> bool -{ -} +#[unstable(feature = "btree_extract_if", issue = "70530")] +impl FusedIterator for ExtractIf<'_, T, F, A> where F: FnMut(&T) -> bool {} #[stable(feature = "rust1", since = "1.0.0")] impl Extend for BTreeSet { diff --git a/library/alloc/src/collections/btree/set/tests.rs b/library/alloc/src/collections/btree/set/tests.rs index 9e4be2f67ec..e05bf0e2003 100644 --- a/library/alloc/src/collections/btree/set/tests.rs +++ b/library/alloc/src/collections/btree/set/tests.rs @@ -366,19 +366,19 @@ fn test_retain() { } #[test] -fn test_drain_filter() { +fn test_extract_if() { let mut x = BTreeSet::from([1]); let mut y = BTreeSet::from([1]); - x.drain_filter(|_| true).for_each(drop); - y.drain_filter(|_| false).for_each(drop); + x.extract_if(|_| true).for_each(drop); + y.extract_if(|_| false).for_each(drop); assert_eq!(x.len(), 0); assert_eq!(y.len(), 1); } #[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] -fn test_drain_filter_drop_panic_leak() { +fn test_extract_if_drop_panic_leak() { let a = CrashTestDummy::new(0); let b = CrashTestDummy::new(1); let c = CrashTestDummy::new(2); @@ -387,7 +387,7 @@ fn test_drain_filter_drop_panic_leak() { set.insert(b.spawn(Panic::InDrop)); set.insert(c.spawn(Panic::Never)); - catch_unwind(move || set.drain_filter(|dummy| dummy.query(true)).for_each(drop)).ok(); + catch_unwind(move || set.extract_if(|dummy| dummy.query(true)).for_each(drop)).ok(); assert_eq!(a.queried(), 1); assert_eq!(b.queried(), 1); @@ -399,7 +399,7 @@ fn test_drain_filter_drop_panic_leak() { #[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] -fn test_drain_filter_pred_panic_leak() { +fn test_extract_if_pred_panic_leak() { let a = CrashTestDummy::new(0); let b = CrashTestDummy::new(1); let c = CrashTestDummy::new(2); @@ -408,10 +408,8 @@ fn test_drain_filter_pred_panic_leak() { set.insert(b.spawn(Panic::InQuery)); set.insert(c.spawn(Panic::InQuery)); - catch_unwind(AssertUnwindSafe(|| { - set.drain_filter(|dummy| dummy.query(true)).for_each(drop) - })) - .ok(); + catch_unwind(AssertUnwindSafe(|| set.extract_if(|dummy| dummy.query(true)).for_each(drop))) + .ok(); assert_eq!(a.queried(), 1); assert_eq!(b.queried(), 1); @@ -608,8 +606,8 @@ fn assert_sync() { v.range(..) } - fn drain_filter(v: &mut BTreeSet) -> impl Sync + '_ { - v.drain_filter(|_| false) + fn extract_if(v: &mut BTreeSet) -> impl Sync + '_ { + v.extract_if(|_| false) } fn difference(v: &BTreeSet) -> impl Sync + '_ { @@ -647,8 +645,8 @@ fn assert_send() { v.range(..) } - fn drain_filter(v: &mut BTreeSet) -> impl Send + '_ { - v.drain_filter(|_| false) + fn extract_if(v: &mut BTreeSet) -> impl Send + '_ { + v.extract_if(|_| false) } fn difference(v: &BTreeSet) -> impl Send + '_ { diff --git a/library/alloc/src/collections/linked_list.rs b/library/alloc/src/collections/linked_list.rs index 2e00e286edc..052edf453f6 100644 --- a/library/alloc/src/collections/linked_list.rs +++ b/library/alloc/src/collections/linked_list.rs @@ -1030,11 +1030,11 @@ impl LinkedList { /// If the closure returns false, the element will remain in the list and will not be yielded /// by the iterator. /// - /// If the returned `DrainFilter` is not exhausted, e.g. because it is dropped without iterating + /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating /// or the iteration short-circuits, then the remaining elements will be retained. - /// Use `drain_filter().for_each(drop)` if you do not need the returned iterator. + /// Use `extract_if().for_each(drop)` if you do not need the returned iterator. /// - /// Note that `drain_filter` lets you mutate every element in the filter closure, regardless of + /// Note that `extract_if` lets you mutate every element in the filter closure, regardless of /// whether you choose to keep or remove it. /// /// # Examples @@ -1042,20 +1042,20 @@ impl LinkedList { /// Splitting a list into evens and odds, reusing the original list: /// /// ``` - /// #![feature(drain_filter)] + /// #![feature(extract_if)] /// use std::collections::LinkedList; /// /// let mut numbers: LinkedList = LinkedList::new(); /// numbers.extend(&[1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15]); /// - /// let evens = numbers.drain_filter(|x| *x % 2 == 0).collect::>(); + /// let evens = numbers.extract_if(|x| *x % 2 == 0).collect::>(); /// let odds = numbers; /// /// assert_eq!(evens.into_iter().collect::>(), vec![2, 4, 6, 8, 14]); /// assert_eq!(odds.into_iter().collect::>(), vec![1, 3, 5, 9, 11, 13, 15]); /// ``` - #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] - pub fn drain_filter(&mut self, filter: F) -> DrainFilter<'_, T, F, A> + #[unstable(feature = "extract_if", reason = "recently added", issue = "43244")] + pub fn extract_if(&mut self, filter: F) -> ExtractIf<'_, T, F, A> where F: FnMut(&mut T) -> bool, { @@ -1063,7 +1063,7 @@ impl LinkedList { let it = self.head; let old_len = self.len; - DrainFilter { list: self, it, pred: filter, idx: 0, old_len } + ExtractIf { list: self, it, pred: filter, idx: 0, old_len } } } @@ -1807,10 +1807,10 @@ impl<'a, T, A: Allocator> CursorMut<'a, T, A> { } } -/// An iterator produced by calling `drain_filter` on LinkedList. -#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] +/// An iterator produced by calling `extract_if` on LinkedList. +#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")] #[must_use = "iterators are lazy and do nothing unless consumed"] -pub struct DrainFilter< +pub struct ExtractIf< 'a, T: 'a, F: 'a, @@ -1825,8 +1825,8 @@ pub struct DrainFilter< old_len: usize, } -#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] -impl Iterator for DrainFilter<'_, T, F, A> +#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")] +impl Iterator for ExtractIf<'_, T, F, A> where F: FnMut(&mut T) -> bool, { @@ -1854,13 +1854,13 @@ where } } -#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] -impl fmt::Debug for DrainFilter<'_, T, F> +#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")] +impl fmt::Debug for ExtractIf<'_, T, F> where F: FnMut(&mut T) -> bool, { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("DrainFilter").field(&self.list).finish() + f.debug_tuple("ExtractIf").field(&self.list).finish() } } diff --git a/library/alloc/src/collections/linked_list/tests.rs b/library/alloc/src/collections/linked_list/tests.rs index 7627b3e8bdc..8dcd59d12d9 100644 --- a/library/alloc/src/collections/linked_list/tests.rs +++ b/library/alloc/src/collections/linked_list/tests.rs @@ -540,10 +540,10 @@ fn test_show() { } #[test] -fn drain_filter_test() { +fn extract_if_test() { let mut m: LinkedList = LinkedList::new(); m.extend(&[1, 2, 3, 4, 5, 6]); - let deleted = m.drain_filter(|v| *v < 4).collect::>(); + let deleted = m.extract_if(|v| *v < 4).collect::>(); check_links(&m); @@ -555,7 +555,7 @@ fn drain_filter_test() { fn drain_to_empty_test() { let mut m: LinkedList = LinkedList::new(); m.extend(&[1, 2, 3, 4, 5, 6]); - let deleted = m.drain_filter(|_| true).collect::>(); + let deleted = m.extract_if(|_| true).collect::>(); check_links(&m); @@ -811,11 +811,11 @@ fn test_contains() { } #[test] -fn drain_filter_empty() { +fn extract_if_empty() { let mut list: LinkedList = LinkedList::new(); { - let mut iter = list.drain_filter(|_| true); + let mut iter = list.extract_if(|_| true); assert_eq!(iter.size_hint(), (0, Some(0))); assert_eq!(iter.next(), None); assert_eq!(iter.size_hint(), (0, Some(0))); @@ -828,13 +828,13 @@ fn drain_filter_empty() { } #[test] -fn drain_filter_zst() { +fn extract_if_zst() { let mut list: LinkedList<_> = [(), (), (), (), ()].into_iter().collect(); let initial_len = list.len(); let mut count = 0; { - let mut iter = list.drain_filter(|_| true); + let mut iter = list.extract_if(|_| true); assert_eq!(iter.size_hint(), (0, Some(initial_len))); while let Some(_) = iter.next() { count += 1; @@ -851,14 +851,14 @@ fn drain_filter_zst() { } #[test] -fn drain_filter_false() { +fn extract_if_false() { let mut list: LinkedList<_> = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].into_iter().collect(); let initial_len = list.len(); let mut count = 0; { - let mut iter = list.drain_filter(|_| false); + let mut iter = list.extract_if(|_| false); assert_eq!(iter.size_hint(), (0, Some(initial_len))); for _ in iter.by_ref() { count += 1; @@ -874,14 +874,14 @@ fn drain_filter_false() { } #[test] -fn drain_filter_true() { +fn extract_if_true() { let mut list: LinkedList<_> = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].into_iter().collect(); let initial_len = list.len(); let mut count = 0; { - let mut iter = list.drain_filter(|_| true); + let mut iter = list.extract_if(|_| true); assert_eq!(iter.size_hint(), (0, Some(initial_len))); while let Some(_) = iter.next() { count += 1; @@ -898,7 +898,7 @@ fn drain_filter_true() { } #[test] -fn drain_filter_complex() { +fn extract_if_complex() { { // [+xxx++++++xxxxx++++x+x++] let mut list = [ @@ -908,7 +908,7 @@ fn drain_filter_complex() { .into_iter() .collect::>(); - let removed = list.drain_filter(|x| *x % 2 == 0).collect::>(); + let removed = list.extract_if(|x| *x % 2 == 0).collect::>(); assert_eq!(removed.len(), 10); assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]); @@ -926,7 +926,7 @@ fn drain_filter_complex() { .into_iter() .collect::>(); - let removed = list.drain_filter(|x| *x % 2 == 0).collect::>(); + let removed = list.extract_if(|x| *x % 2 == 0).collect::>(); assert_eq!(removed.len(), 10); assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]); @@ -944,7 +944,7 @@ fn drain_filter_complex() { .into_iter() .collect::>(); - let removed = list.drain_filter(|x| *x % 2 == 0).collect::>(); + let removed = list.extract_if(|x| *x % 2 == 0).collect::>(); assert_eq!(removed.len(), 10); assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]); @@ -961,7 +961,7 @@ fn drain_filter_complex() { .into_iter() .collect::>(); - let removed = list.drain_filter(|x| *x % 2 == 0).collect::>(); + let removed = list.extract_if(|x| *x % 2 == 0).collect::>(); assert_eq!(removed.len(), 10); assert_eq!(removed, vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]); @@ -975,7 +975,7 @@ fn drain_filter_complex() { .into_iter() .collect::>(); - let removed = list.drain_filter(|x| *x % 2 == 0).collect::>(); + let removed = list.extract_if(|x| *x % 2 == 0).collect::>(); assert_eq!(removed.len(), 10); assert_eq!(removed, vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]); @@ -986,7 +986,7 @@ fn drain_filter_complex() { #[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] -fn drain_filter_drop_panic_leak() { +fn extract_if_drop_panic_leak() { let d0 = CrashTestDummy::new(0); let d1 = CrashTestDummy::new(1); let d2 = CrashTestDummy::new(2); @@ -1005,7 +1005,7 @@ fn drain_filter_drop_panic_leak() { q.push_front(d1.spawn(Panic::InDrop)); q.push_front(d0.spawn(Panic::Never)); - catch_unwind(AssertUnwindSafe(|| q.drain_filter(|_| true).for_each(drop))).unwrap_err(); + catch_unwind(AssertUnwindSafe(|| q.extract_if(|_| true).for_each(drop))).unwrap_err(); assert_eq!(d0.dropped(), 1); assert_eq!(d1.dropped(), 1); @@ -1026,7 +1026,7 @@ fn drain_filter_drop_panic_leak() { #[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] -fn drain_filter_pred_panic_leak() { +fn extract_if_pred_panic_leak() { static mut DROPS: i32 = 0; #[derive(Debug)] @@ -1051,7 +1051,7 @@ fn drain_filter_pred_panic_leak() { q.push_front(D(0)); catch_unwind(AssertUnwindSafe(|| { - q.drain_filter(|item| if item.0 >= 2 { panic!() } else { true }).for_each(drop) + q.extract_if(|item| if item.0 >= 2 { panic!() } else { true }).for_each(drop) })) .ok(); diff --git a/library/alloc/src/vec/drain_filter.rs b/library/alloc/src/vec/drain_filter.rs deleted file mode 100644 index ebee3d6eca0..00000000000 --- a/library/alloc/src/vec/drain_filter.rs +++ /dev/null @@ -1,121 +0,0 @@ -use crate::alloc::{Allocator, Global}; -use core::ptr; -use core::slice; - -use super::Vec; - -/// An iterator which uses a closure to determine if an element should be removed. -/// -/// This struct is created by [`Vec::drain_filter`]. -/// See its documentation for more. -/// -/// # Example -/// -/// ``` -/// #![feature(drain_filter)] -/// -/// let mut v = vec![0, 1, 2]; -/// let iter: std::vec::DrainFilter<'_, _, _> = v.drain_filter(|x| *x % 2 == 0); -/// ``` -#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] -#[derive(Debug)] -#[must_use = "iterators are lazy and do nothing unless consumed"] -pub struct DrainFilter< - 'a, - T, - F, - #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global, -> where - F: FnMut(&mut T) -> bool, -{ - pub(super) vec: &'a mut Vec, - /// The index of the item that will be inspected by the next call to `next`. - pub(super) idx: usize, - /// The number of items that have been drained (removed) thus far. - pub(super) del: usize, - /// The original length of `vec` prior to draining. - pub(super) old_len: usize, - /// The filter test predicate. - pub(super) pred: F, - /// A flag that indicates a panic has occurred in the filter test predicate. - /// This is used as a hint in the drop implementation 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. - pub(super) panic_flag: bool, -} - -impl DrainFilter<'_, T, F, A> -where - F: FnMut(&mut T) -> bool, -{ - /// Returns a reference to the underlying allocator. - #[unstable(feature = "allocator_api", issue = "32838")] - #[inline] - pub fn allocator(&self) -> &A { - self.vec.allocator() - } -} - -#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] -impl Iterator for DrainFilter<'_, T, F, A> -where - F: FnMut(&mut T) -> bool, -{ - type Item = T; - - fn next(&mut self) -> Option { - unsafe { - while self.idx < self.old_len { - let i = self.idx; - let v = slice::from_raw_parts_mut(self.vec.as_mut_ptr(), self.old_len); - 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]; - ptr::copy_nonoverlapping(src, dst, 1); - } - } - None - } - } - - fn size_hint(&self) -> (usize, Option) { - (0, Some(self.old_len - self.idx)) - } -} - -#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] -impl Drop for DrainFilter<'_, T, F, A> -where - F: FnMut(&mut T) -> bool, -{ - fn drop(&mut self) { - unsafe { - if self.idx < self.old_len && self.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.vec.as_mut_ptr(); - let src = ptr.add(self.idx); - let dst = src.sub(self.del); - let tail_len = self.old_len - self.idx; - src.copy_to(dst, tail_len); - } - self.vec.set_len(self.old_len - self.del); - } - } -} diff --git a/library/alloc/src/vec/extract_if.rs b/library/alloc/src/vec/extract_if.rs new file mode 100644 index 00000000000..e8e6bd56d21 --- /dev/null +++ b/library/alloc/src/vec/extract_if.rs @@ -0,0 +1,121 @@ +use crate::alloc::{Allocator, Global}; +use core::ptr; +use core::slice; + +use super::Vec; + +/// An iterator which uses a closure to determine if an element should be removed. +/// +/// This struct is created by [`Vec::extract_if`]. +/// See its documentation for more. +/// +/// # Example +/// +/// ``` +/// #![feature(extract_if)] +/// +/// let mut v = vec![0, 1, 2]; +/// let iter: std::vec::ExtractIf<'_, _, _> = v.extract_if(|x| *x % 2 == 0); +/// ``` +#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")] +#[derive(Debug)] +#[must_use = "iterators are lazy and do nothing unless consumed"] +pub struct ExtractIf< + 'a, + T, + F, + #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global, +> where + F: FnMut(&mut T) -> bool, +{ + pub(super) vec: &'a mut Vec, + /// The index of the item that will be inspected by the next call to `next`. + pub(super) idx: usize, + /// The number of items that have been drained (removed) thus far. + pub(super) del: usize, + /// The original length of `vec` prior to draining. + pub(super) old_len: usize, + /// The filter test predicate. + pub(super) pred: F, + /// A flag that indicates a panic has occurred in the filter test predicate. + /// This is used as a hint in the drop implementation to prevent consumption + /// of the remainder of the `ExtractIf`. Any unprocessed items will be + /// backshifted in the `vec`, but no further items will be dropped or + /// tested by the filter predicate. + pub(super) panic_flag: bool, +} + +impl ExtractIf<'_, T, F, A> +where + F: FnMut(&mut T) -> bool, +{ + /// Returns a reference to the underlying allocator. + #[unstable(feature = "allocator_api", issue = "32838")] + #[inline] + pub fn allocator(&self) -> &A { + self.vec.allocator() + } +} + +#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")] +impl Iterator for ExtractIf<'_, T, F, A> +where + F: FnMut(&mut T) -> bool, +{ + type Item = T; + + fn next(&mut self) -> Option { + unsafe { + while self.idx < self.old_len { + let i = self.idx; + let v = slice::from_raw_parts_mut(self.vec.as_mut_ptr(), self.old_len); + 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]; + ptr::copy_nonoverlapping(src, dst, 1); + } + } + None + } + } + + fn size_hint(&self) -> (usize, Option) { + (0, Some(self.old_len - self.idx)) + } +} + +#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")] +impl Drop for ExtractIf<'_, T, F, A> +where + F: FnMut(&mut T) -> bool, +{ + fn drop(&mut self) { + unsafe { + if self.idx < self.old_len && self.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.vec.as_mut_ptr(); + let src = ptr.add(self.idx); + let dst = src.sub(self.del); + let tail_len = self.old_len - self.idx; + src.copy_to(dst, tail_len); + } + self.vec.set_len(self.old_len - self.del); + } + } +} diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs index 75f1a96c4c4..289bbc7d2ef 100644 --- a/library/alloc/src/vec/mod.rs +++ b/library/alloc/src/vec/mod.rs @@ -71,10 +71,10 @@ use crate::boxed::Box; use crate::collections::TryReserveError; use crate::raw_vec::RawVec; -#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] -pub use self::drain_filter::DrainFilter; +#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")] +pub use self::extract_if::ExtractIf; -mod drain_filter; +mod extract_if; #[cfg(not(no_global_oom_handling))] #[stable(feature = "vec_splice", since = "1.21.0")] @@ -2892,7 +2892,7 @@ impl Vec { /// If the closure returns false, the element will remain in the vector and will not be yielded /// by the iterator. /// - /// If the returned `DrainFilter` is not exhausted, e.g. because it is dropped without iterating + /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating /// or the iteration short-circuits, then the remaining elements will be retained. /// Use [`retain`] with a negated predicate if you do not need the returned iterator. /// @@ -2916,10 +2916,10 @@ impl Vec { /// # assert_eq!(vec, vec![1, 4, 5]); /// ``` /// - /// But `drain_filter` is easier to use. `drain_filter` is also more efficient, + /// But `extract_if` is easier to use. `extract_if` is also more efficient, /// because it can backshift the elements of the array in bulk. /// - /// Note that `drain_filter` also lets you mutate every element in the filter closure, + /// Note that `extract_if` also lets you mutate every element in the filter closure, /// regardless of whether you choose to keep or remove it. /// /// # Examples @@ -2927,17 +2927,17 @@ impl Vec { /// Splitting an array into evens and odds, reusing the original allocation: /// /// ``` - /// #![feature(drain_filter)] + /// #![feature(extract_if)] /// let mut numbers = vec![1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15]; /// - /// let evens = numbers.drain_filter(|x| *x % 2 == 0).collect::>(); + /// let evens = numbers.extract_if(|x| *x % 2 == 0).collect::>(); /// let odds = numbers; /// /// assert_eq!(evens, vec![2, 4, 6, 8, 14]); /// assert_eq!(odds, vec![1, 3, 5, 9, 11, 13, 15]); /// ``` - #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] - pub fn drain_filter(&mut self, filter: F) -> DrainFilter<'_, T, F, A> + #[unstable(feature = "extract_if", reason = "recently added", issue = "43244")] + pub fn extract_if(&mut self, filter: F) -> ExtractIf<'_, T, F, A> where F: FnMut(&mut T) -> bool, { @@ -2948,7 +2948,7 @@ impl Vec { self.set_len(0); } - DrainFilter { vec: self, idx: 0, del: 0, old_len, pred: filter, panic_flag: false } + ExtractIf { vec: self, idx: 0, del: 0, old_len, pred: filter, panic_flag: false } } } diff --git a/library/alloc/tests/autotraits.rs b/library/alloc/tests/autotraits.rs index 879e32b3fa3..6a8e55bff23 100644 --- a/library/alloc/tests/autotraits.rs +++ b/library/alloc/tests/autotraits.rs @@ -55,7 +55,7 @@ fn test_btree_map() { require_send_sync(async { let _v = None::< - alloc::collections::btree_map::DrainFilter< + alloc::collections::btree_map::ExtractIf< '_, &u32, &u32, @@ -149,7 +149,7 @@ fn test_btree_set() { }); require_send_sync(async { - let _v = None:: bool>>; + let _v = None:: bool>>; async {}.await; }); @@ -238,7 +238,7 @@ fn test_linked_list() { /* require_send_sync(async { let _v = - None:: bool>>; + None:: bool>>; async {}.await; }); */ diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs index 0eca4c9bb07..aa7a331b368 100644 --- a/library/alloc/tests/lib.rs +++ b/library/alloc/tests/lib.rs @@ -1,7 +1,7 @@ #![feature(allocator_api)] #![feature(alloc_layout_extra)] #![feature(assert_matches)] -#![feature(btree_drain_filter)] +#![feature(btree_extract_if)] #![feature(cow_is_borrowed)] #![feature(const_cow_is_borrowed)] #![feature(const_heap)] @@ -10,7 +10,7 @@ #![feature(const_ptr_write)] #![feature(const_try)] #![feature(core_intrinsics)] -#![feature(drain_filter)] +#![feature(extract_if)] #![feature(exact_size_is_empty)] #![feature(linked_list_cursors)] #![feature(map_try_insert)] diff --git a/library/alloc/tests/vec.rs b/library/alloc/tests/vec.rs index acb744ad9a0..21824c8a17c 100644 --- a/library/alloc/tests/vec.rs +++ b/library/alloc/tests/vec.rs @@ -1347,11 +1347,11 @@ fn overaligned_allocations() { } #[test] -fn drain_filter_empty() { +fn extract_if_empty() { let mut vec: Vec = vec![]; { - let mut iter = vec.drain_filter(|_| true); + let mut iter = vec.extract_if(|_| true); assert_eq!(iter.size_hint(), (0, Some(0))); assert_eq!(iter.next(), None); assert_eq!(iter.size_hint(), (0, Some(0))); @@ -1363,12 +1363,12 @@ fn drain_filter_empty() { } #[test] -fn drain_filter_zst() { +fn extract_if_zst() { let mut vec = vec![(), (), (), (), ()]; let initial_len = vec.len(); let mut count = 0; { - let mut iter = vec.drain_filter(|_| true); + let mut iter = vec.extract_if(|_| true); assert_eq!(iter.size_hint(), (0, Some(initial_len))); while let Some(_) = iter.next() { count += 1; @@ -1385,13 +1385,13 @@ fn drain_filter_zst() { } #[test] -fn drain_filter_false() { +fn extract_if_false() { let mut vec = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; let initial_len = vec.len(); let mut count = 0; { - let mut iter = vec.drain_filter(|_| false); + let mut iter = vec.extract_if(|_| false); assert_eq!(iter.size_hint(), (0, Some(initial_len))); for _ in iter.by_ref() { count += 1; @@ -1407,13 +1407,13 @@ fn drain_filter_false() { } #[test] -fn drain_filter_true() { +fn extract_if_true() { let mut vec = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; let initial_len = vec.len(); let mut count = 0; { - let mut iter = vec.drain_filter(|_| true); + let mut iter = vec.extract_if(|_| true); assert_eq!(iter.size_hint(), (0, Some(initial_len))); while let Some(_) = iter.next() { count += 1; @@ -1430,7 +1430,7 @@ fn drain_filter_true() { } #[test] -fn drain_filter_complex() { +fn extract_if_complex() { { // [+xxx++++++xxxxx++++x+x++] let mut vec = vec![ @@ -1438,7 +1438,7 @@ fn drain_filter_complex() { 39, ]; - let removed = vec.drain_filter(|x| *x % 2 == 0).collect::>(); + let removed = vec.extract_if(|x| *x % 2 == 0).collect::>(); assert_eq!(removed.len(), 10); assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]); @@ -1452,7 +1452,7 @@ fn drain_filter_complex() { 2, 4, 6, 7, 9, 11, 13, 15, 17, 18, 20, 22, 24, 26, 27, 29, 31, 33, 34, 35, 36, 37, 39, ]; - let removed = vec.drain_filter(|x| *x % 2 == 0).collect::>(); + let removed = vec.extract_if(|x| *x % 2 == 0).collect::>(); assert_eq!(removed.len(), 10); assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]); @@ -1465,7 +1465,7 @@ fn drain_filter_complex() { let mut vec = vec![2, 4, 6, 7, 9, 11, 13, 15, 17, 18, 20, 22, 24, 26, 27, 29, 31, 33, 34, 35, 36]; - let removed = vec.drain_filter(|x| *x % 2 == 0).collect::>(); + let removed = vec.extract_if(|x| *x % 2 == 0).collect::>(); assert_eq!(removed.len(), 10); assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]); @@ -1477,7 +1477,7 @@ fn drain_filter_complex() { // [xxxxxxxxxx+++++++++++] let mut vec = vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19]; - let removed = vec.drain_filter(|x| *x % 2 == 0).collect::>(); + let removed = vec.extract_if(|x| *x % 2 == 0).collect::>(); assert_eq!(removed.len(), 10); assert_eq!(removed, vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]); @@ -1489,7 +1489,7 @@ fn drain_filter_complex() { // [+++++++++++xxxxxxxxxx] let mut vec = vec![1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20]; - let removed = vec.drain_filter(|x| *x % 2 == 0).collect::>(); + let removed = vec.extract_if(|x| *x % 2 == 0).collect::>(); assert_eq!(removed.len(), 10); assert_eq!(removed, vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]); @@ -1502,7 +1502,7 @@ fn drain_filter_complex() { #[test] #[cfg(not(target_os = "emscripten"))] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] -fn drain_filter_consumed_panic() { +fn extract_if_consumed_panic() { use std::rc::Rc; use std::sync::Mutex; @@ -1537,9 +1537,9 @@ fn drain_filter_consumed_panic() { } c.index < 6 }; - let drain = data.drain_filter(filter); + let drain = data.extract_if(filter); - // NOTE: The DrainFilter is explicitly consumed + // NOTE: The ExtractIf is explicitly consumed drain.for_each(drop); }); @@ -1555,7 +1555,7 @@ fn drain_filter_consumed_panic() { #[test] #[cfg(not(target_os = "emscripten"))] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] -fn drain_filter_unconsumed_panic() { +fn extract_if_unconsumed_panic() { use std::rc::Rc; use std::sync::Mutex; @@ -1590,9 +1590,9 @@ fn drain_filter_unconsumed_panic() { } c.index < 6 }; - let _drain = data.drain_filter(filter); + let _drain = data.extract_if(filter); - // NOTE: The DrainFilter is dropped without being consumed + // NOTE: The ExtractIf is dropped without being consumed }); let drop_counts = drop_counts.lock().unwrap(); @@ -1604,9 +1604,9 @@ fn drain_filter_unconsumed_panic() { } #[test] -fn drain_filter_unconsumed() { +fn extract_if_unconsumed() { let mut vec = vec![1, 2, 3, 4]; - let drain = vec.drain_filter(|&mut x| x % 2 != 0); + let drain = vec.extract_if(|&mut x| x % 2 != 0); drop(drain); assert_eq!(vec, [1, 2, 3, 4]); } -- cgit 1.4.1-3-g733a5