| use super::plumbing::*; |
| use super::*; |
| use std::sync::atomic::{AtomicBool, Ordering}; |
| |
| /// `WhileSome` is an iterator that yields the `Some` elements of an iterator, |
| /// halting as soon as any `None` is produced. |
| /// |
| /// This struct is created by the [`while_some()`] method on [`ParallelIterator`] |
| /// |
| /// [`while_some()`]: trait.ParallelIterator.html#method.while_some |
| /// [`ParallelIterator`]: trait.ParallelIterator.html |
| #[must_use = "iterator adaptors are lazy and do nothing unless consumed"] |
| #[derive(Debug, Clone)] |
| pub struct WhileSome<I: ParallelIterator> { |
| base: I, |
| } |
| |
| impl<I> WhileSome<I> |
| where |
| I: ParallelIterator, |
| { |
| /// Creates a new `WhileSome` iterator. |
| pub(super) fn new(base: I) -> Self { |
| WhileSome { base } |
| } |
| } |
| |
| impl<I, T> ParallelIterator for WhileSome<I> |
| where |
| I: ParallelIterator<Item = Option<T>>, |
| T: Send, |
| { |
| type Item = T; |
| |
| fn drive_unindexed<C>(self, consumer: C) -> C::Result |
| where |
| C: UnindexedConsumer<Self::Item>, |
| { |
| let full = AtomicBool::new(false); |
| let consumer1 = WhileSomeConsumer { |
| base: consumer, |
| full: &full, |
| }; |
| self.base.drive_unindexed(consumer1) |
| } |
| } |
| |
| /// //////////////////////////////////////////////////////////////////////// |
| /// Consumer implementation |
| |
| struct WhileSomeConsumer<'f, C> { |
| base: C, |
| full: &'f AtomicBool, |
| } |
| |
| impl<'f, T, C> Consumer<Option<T>> for WhileSomeConsumer<'f, C> |
| where |
| C: Consumer<T>, |
| T: Send, |
| { |
| type Folder = WhileSomeFolder<'f, C::Folder>; |
| type Reducer = C::Reducer; |
| type Result = C::Result; |
| |
| fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) { |
| let (left, right, reducer) = self.base.split_at(index); |
| ( |
| WhileSomeConsumer { base: left, ..self }, |
| WhileSomeConsumer { |
| base: right, |
| ..self |
| }, |
| reducer, |
| ) |
| } |
| |
| fn into_folder(self) -> Self::Folder { |
| WhileSomeFolder { |
| base: self.base.into_folder(), |
| full: self.full, |
| } |
| } |
| |
| fn full(&self) -> bool { |
| self.full.load(Ordering::Relaxed) || self.base.full() |
| } |
| } |
| |
| impl<'f, T, C> UnindexedConsumer<Option<T>> for WhileSomeConsumer<'f, C> |
| where |
| C: UnindexedConsumer<T>, |
| T: Send, |
| { |
| fn split_off_left(&self) -> Self { |
| WhileSomeConsumer { |
| base: self.base.split_off_left(), |
| ..*self |
| } |
| } |
| |
| fn to_reducer(&self) -> Self::Reducer { |
| self.base.to_reducer() |
| } |
| } |
| |
| struct WhileSomeFolder<'f, C> { |
| base: C, |
| full: &'f AtomicBool, |
| } |
| |
| impl<'f, T, C> Folder<Option<T>> for WhileSomeFolder<'f, C> |
| where |
| C: Folder<T>, |
| { |
| type Result = C::Result; |
| |
| fn consume(mut self, item: Option<T>) -> Self { |
| match item { |
| Some(item) => self.base = self.base.consume(item), |
| None => self.full.store(true, Ordering::Relaxed), |
| } |
| self |
| } |
| |
| fn consume_iter<I>(mut self, iter: I) -> Self |
| where |
| I: IntoIterator<Item = Option<T>>, |
| { |
| fn some<T>(full: &AtomicBool) -> impl Fn(&Option<T>) -> bool + '_ { |
| move |x| match *x { |
| Some(_) => !full.load(Ordering::Relaxed), |
| None => { |
| full.store(true, Ordering::Relaxed); |
| false |
| } |
| } |
| } |
| |
| self.base = self.base.consume_iter( |
| iter.into_iter() |
| .take_while(some(self.full)) |
| .map(Option::unwrap), |
| ); |
| self |
| } |
| |
| fn complete(self) -> C::Result { |
| self.base.complete() |
| } |
| |
| fn full(&self) -> bool { |
| self.full.load(Ordering::Relaxed) || self.base.full() |
| } |
| } |