| //! This module contains the parallel iterator types for double-ended queues |
| //! (`VecDeque<T>`). You will rarely need to interact with it directly |
| //! 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; |
| |
| /// Parallel iterator over a double-ended queue |
| #[derive(Debug, Clone)] |
| pub struct IntoIter<T: Send> { |
| inner: vec::IntoIter<T>, |
| } |
| |
| 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! { |
| IntoIter<T> => T, |
| impl<T: Send> |
| } |
| |
| /// Parallel iterator over an immutable reference to a double-ended queue |
| #[derive(Debug)] |
| pub struct Iter<'a, T: Sync> { |
| inner: Chain<slice::Iter<'a, T>, slice::Iter<'a, T>>, |
| } |
| |
| impl<'a, T: Sync> Clone for Iter<'a, T> { |
| fn clone(&self) -> Self { |
| Iter { |
| inner: self.inner.clone(), |
| } |
| } |
| } |
| |
| impl<'a, T: Sync> IntoParallelIterator for &'a VecDeque<T> { |
| type Item = &'a T; |
| type Iter = Iter<'a, T>; |
| |
| fn into_par_iter(self) -> Self::Iter { |
| let (a, b) = self.as_slices(); |
| Iter { |
| inner: a.into_par_iter().chain(b), |
| } |
| } |
| } |
| |
| delegate_indexed_iterator! { |
| Iter<'a, T> => &'a T, |
| impl<'a, T: Sync + 'a> |
| } |
| |
| /// Parallel iterator over a mutable reference to a double-ended queue |
| #[derive(Debug)] |
| pub struct IterMut<'a, T: Send> { |
| inner: Chain<slice::IterMut<'a, T>, slice::IterMut<'a, T>>, |
| } |
| |
| impl<'a, T: Send> IntoParallelIterator for &'a mut VecDeque<T> { |
| type Item = &'a mut T; |
| type Iter = IterMut<'a, T>; |
| |
| fn into_par_iter(self) -> Self::Iter { |
| let (a, b) = self.as_mut_slices(); |
| IterMut { |
| inner: a.into_par_iter().chain(b), |
| } |
| } |
| } |
| |
| 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()); |
| } |
| } |
| } |