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-rw-r--r--rust/alloc/vec/mod.rs110
1 files changed, 53 insertions, 57 deletions
diff --git a/rust/alloc/vec/mod.rs b/rust/alloc/vec/mod.rs
index 05c70de0227ed..209a88cfe598f 100644
--- a/rust/alloc/vec/mod.rs
+++ b/rust/alloc/vec/mod.rs
@@ -74,10 +74,10 @@ use crate::boxed::Box;
use crate::collections::{TryReserveError, TryReserveErrorKind};
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")]
@@ -216,7 +216,7 @@ mod spec_extend;
///
/// # Indexing
///
-/// The `Vec` type allows to access values by index, because it implements the
+/// The `Vec` type allows access to values by index, because it implements the
/// [`Index`] trait. An example will be more explicit:
///
/// ```
@@ -618,22 +618,20 @@ impl<T> Vec<T> {
/// Using memory that was allocated elsewhere:
///
/// ```rust
- /// #![feature(allocator_api)]
- ///
- /// use std::alloc::{AllocError, Allocator, Global, Layout};
+ /// use std::alloc::{alloc, Layout};
///
/// fn main() {
/// let layout = Layout::array::<u32>(16).expect("overflow cannot happen");
///
/// let vec = unsafe {
- /// let mem = match Global.allocate(layout) {
- /// Ok(mem) => mem.cast::<u32>().as_ptr(),
- /// Err(AllocError) => return,
- /// };
+ /// let mem = alloc(layout).cast::<u32>();
+ /// if mem.is_null() {
+ /// return;
+ /// }
///
/// mem.write(1_000_000);
///
- /// Vec::from_raw_parts_in(mem, 1, 16, Global)
+ /// Vec::from_raw_parts(mem, 1, 16)
/// };
///
/// assert_eq!(vec, &[1_000_000]);
@@ -876,19 +874,22 @@ impl<T, A: Allocator> Vec<T, A> {
/// Using memory that was allocated elsewhere:
///
/// ```rust
- /// use std::alloc::{alloc, Layout};
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::{AllocError, Allocator, Global, Layout};
///
/// fn main() {
/// let layout = Layout::array::<u32>(16).expect("overflow cannot happen");
+ ///
/// let vec = unsafe {
- /// let mem = alloc(layout).cast::<u32>();
- /// if mem.is_null() {
- /// return;
- /// }
+ /// let mem = match Global.allocate(layout) {
+ /// Ok(mem) => mem.cast::<u32>().as_ptr(),
+ /// Err(AllocError) => return,
+ /// };
///
/// mem.write(1_000_000);
///
- /// Vec::from_raw_parts(mem, 1, 16)
+ /// Vec::from_raw_parts_in(mem, 1, 16, Global)
/// };
///
/// assert_eq!(vec, &[1_000_000]);
@@ -2507,7 +2508,7 @@ impl<T: Clone, A: Allocator> Vec<T, A> {
let len = self.len();
if new_len > len {
- self.extend_with(new_len - len, ExtendElement(value))
+ self.extend_with(new_len - len, value)
} else {
self.truncate(new_len);
}
@@ -2545,7 +2546,7 @@ impl<T: Clone, A: Allocator> Vec<T, A> {
let len = self.len();
if new_len > len {
- self.try_extend_with(new_len - len, ExtendElement(value))
+ self.try_extend_with(new_len - len, value)
} else {
self.truncate(new_len);
Ok(())
@@ -2684,26 +2685,10 @@ impl<T, A: Allocator, const N: usize> Vec<[T; N], A> {
}
}
-// This code generalizes `extend_with_{element,default}`.
-trait ExtendWith<T> {
- fn next(&mut self) -> T;
- fn last(self) -> T;
-}
-
-struct ExtendElement<T>(T);
-impl<T: Clone> ExtendWith<T> for ExtendElement<T> {
- fn next(&mut self) -> T {
- self.0.clone()
- }
- fn last(self) -> T {
- self.0
- }
-}
-
-impl<T, A: Allocator> Vec<T, A> {
+impl<T: Clone, A: Allocator> Vec<T, A> {
#[cfg(not(no_global_oom_handling))]
- /// Extend the vector by `n` values, using the given generator.
- fn extend_with<E: ExtendWith<T>>(&mut self, n: usize, mut value: E) {
+ /// Extend the vector by `n` clones of value.
+ fn extend_with(&mut self, n: usize, value: T) {
self.reserve(n);
unsafe {
@@ -2715,15 +2700,15 @@ impl<T, A: Allocator> Vec<T, A> {
// Write all elements except the last one
for _ in 1..n {
- ptr::write(ptr, value.next());
+ ptr::write(ptr, value.clone());
ptr = ptr.add(1);
- // Increment the length in every step in case next() panics
+ // Increment the length in every step in case clone() panics
local_len.increment_len(1);
}
if n > 0 {
// We can write the last element directly without cloning needlessly
- ptr::write(ptr, value.last());
+ ptr::write(ptr, value);
local_len.increment_len(1);
}
@@ -2731,8 +2716,8 @@ impl<T, A: Allocator> Vec<T, A> {
}
}
- /// Try to extend the vector by `n` values, using the given generator.
- fn try_extend_with<E: ExtendWith<T>>(&mut self, n: usize, mut value: E) -> Result<(), TryReserveError> {
+ /// Try to extend the vector by `n` clones of value.
+ fn try_extend_with(&mut self, n: usize, value: T) -> Result<(), TryReserveError> {
self.try_reserve(n)?;
unsafe {
@@ -2744,15 +2729,15 @@ impl<T, A: Allocator> Vec<T, A> {
// Write all elements except the last one
for _ in 1..n {
- ptr::write(ptr, value.next());
+ ptr::write(ptr, value.clone());
ptr = ptr.add(1);
- // Increment the length in every step in case next() panics
+ // Increment the length in every step in case clone() panics
local_len.increment_len(1);
}
if n > 0 {
// We can write the last element directly without cloning needlessly
- ptr::write(ptr, value.last());
+ ptr::write(ptr, value);
local_len.increment_len(1);
}
@@ -3210,6 +3195,12 @@ impl<T, A: Allocator> Vec<T, A> {
/// If the closure returns false, the element will remain in the vector and will not be yielded
/// by the iterator.
///
+ /// 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.
+ ///
+ /// [`retain`]: Vec::retain
+ ///
/// Using this method is equivalent to the following code:
///
/// ```
@@ -3228,10 +3219,10 @@ impl<T, A: Allocator> Vec<T, A> {
/// # 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
@@ -3239,17 +3230,17 @@ impl<T, A: Allocator> Vec<T, A> {
/// 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::<Vec<_>>();
+ /// let evens = numbers.extract_if(|x| *x % 2 == 0).collect::<Vec<_>>();
/// 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<F>(&mut self, filter: F) -> DrainFilter<'_, T, F, A>
+ #[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+ pub fn extract_if<F>(&mut self, filter: F) -> ExtractIf<'_, T, F, A>
where
F: FnMut(&mut T) -> bool,
{
@@ -3260,7 +3251,7 @@ impl<T, A: Allocator> Vec<T, A> {
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 }
}
}
@@ -3272,7 +3263,7 @@ impl<T, A: Allocator> Vec<T, A> {
/// [`copy_from_slice`]: slice::copy_from_slice
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "extend_ref", since = "1.2.0")]
-impl<'a, T: Copy + 'a, A: Allocator + 'a> Extend<&'a T> for Vec<T, A> {
+impl<'a, T: Copy + 'a, A: Allocator> Extend<&'a T> for Vec<T, A> {
fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) {
self.spec_extend(iter.into_iter())
}
@@ -3290,9 +3281,14 @@ impl<'a, T: Copy + 'a, A: Allocator + 'a> Extend<&'a T> for Vec<T, A> {
/// Implements comparison of vectors, [lexicographically](Ord#lexicographical-comparison).
#[stable(feature = "rust1", since = "1.0.0")]
-impl<T: PartialOrd, A: Allocator> PartialOrd for Vec<T, A> {
+impl<T, A1, A2> PartialOrd<Vec<T, A2>> for Vec<T, A1>
+where
+ T: PartialOrd,
+ A1: Allocator,
+ A2: Allocator,
+{
#[inline]
- fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+ fn partial_cmp(&self, other: &Vec<T, A2>) -> Option<Ordering> {
PartialOrd::partial_cmp(&**self, &**other)
}
}
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-05-20 10:25:16 +0000