New upstream version 1.63.0+dfsg1

[rustc.git] / vendor / rustc-rayon / src / collections / vec_deque.rs

diff --git a/vendor/rustc-rayon/src/collections/vec_deque.rs b/vendor/rustc-rayon/src/collections/vec_deque.rs
index 54494c471acb094ed8d4dd7e7e4ea26e0b64ead6..f87ce6b1855c6661febd2f32e007f009b6c4d82b 100644 (file)
--- a/vendor/rustc-rayon/src/collections/vec_deque.rs
+++ b/vendor/rustc-rayon/src/collections/vec_deque.rs
@@ -3,9 +3,11 @@
 //! unless you have need to name one of the iterator types.
 
 use std::collections::VecDeque;
+use std::ops::{Range, RangeBounds};
 
 use crate::iter::plumbing::*;
 use crate::iter::*;
+use crate::math::simplify_range;
 
 use crate::slice;
 use crate::vec;
@@ -16,9 +18,15 @@ pub struct IntoIter<T: Send> {
     inner: vec::IntoIter<T>,
 }
 
-into_par_vec! {
-    VecDeque<T> => IntoIter<T>,
-    impl<T: Send>
+impl<T: Send> IntoParallelIterator for VecDeque<T> {
+    type Item = T;
+    type Iter = IntoIter<T>;
+
+    fn into_par_iter(self) -> Self::Iter {
+        // NOTE: requires data movement if the deque doesn't start at offset 0.
+        let inner = Vec::from(self).into_par_iter();
+        IntoIter { inner }
+    }
 }
 
 delegate_indexed_iterator! {
@@ -79,3 +87,73 @@ delegate_indexed_iterator! {
     IterMut<'a, T> => &'a mut T,
     impl<'a, T: Send + 'a>
 }
+
+/// Draining parallel iterator that moves a range out of a double-ended queue,
+/// but keeps the total capacity.
+#[derive(Debug)]
+pub struct Drain<'a, T: Send> {
+    deque: &'a mut VecDeque<T>,
+    range: Range<usize>,
+    orig_len: usize,
+}
+
+impl<'a, T: Send> ParallelDrainRange<usize> for &'a mut VecDeque<T> {
+    type Iter = Drain<'a, T>;
+    type Item = T;
+
+    fn par_drain<R: RangeBounds<usize>>(self, range: R) -> Self::Iter {
+        Drain {
+            orig_len: self.len(),
+            range: simplify_range(range, self.len()),
+            deque: self,
+        }
+    }
+}
+
+impl<'a, T: Send> ParallelIterator for Drain<'a, T> {
+    type Item = T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        bridge(self, consumer)
+    }
+
+    fn opt_len(&self) -> Option<usize> {
+        Some(self.len())
+    }
+}
+
+impl<'a, T: Send> IndexedParallelIterator for Drain<'a, T> {
+    fn drive<C>(self, consumer: C) -> C::Result
+    where
+        C: Consumer<Self::Item>,
+    {
+        bridge(self, consumer)
+    }
+
+    fn len(&self) -> usize {
+        self.range.len()
+    }
+
+    fn with_producer<CB>(self, callback: CB) -> CB::Output
+    where
+        CB: ProducerCallback<Self::Item>,
+    {
+        // NOTE: requires data movement if the deque doesn't start at offset 0.
+        super::DrainGuard::new(self.deque)
+            .par_drain(self.range.clone())
+            .with_producer(callback)
+    }
+}
+
+impl<'a, T: Send> Drop for Drain<'a, T> {
+    fn drop(&mut self) {
+        if self.deque.len() != self.orig_len - self.range.len() {
+            // We must not have produced, so just call a normal drain to remove the items.
+            assert_eq!(self.deque.len(), self.orig_len);
+            self.deque.drain(self.range.clone());
+        }
+    }
+}