| use super::plumbing::*; |
| use super::*; |
| |
| use std::fmt::{self, Debug}; |
| |
| /// `Filter` takes a predicate `filter_op` and filters out elements that match. |
| /// This struct is created by the [`filter()`] method on [`ParallelIterator`] |
| /// |
| /// [`filter()`]: trait.ParallelIterator.html#method.filter |
| /// [`ParallelIterator`]: trait.ParallelIterator.html |
| #[must_use = "iterator adaptors are lazy and do nothing unless consumed"] |
| #[derive(Clone)] |
| pub struct Filter<I: ParallelIterator, P> { |
| base: I, |
| filter_op: P, |
| } |
| |
| impl<I: ParallelIterator + Debug, P> Debug for Filter<I, P> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.debug_struct("Filter").field("base", &self.base).finish() |
| } |
| } |
| |
| impl<I, P> Filter<I, P> |
| where |
| I: ParallelIterator, |
| { |
| /// Create a new `Filter` iterator. |
| pub(super) fn new(base: I, filter_op: P) -> Self { |
| Filter { base, filter_op } |
| } |
| } |
| |
| impl<I, P> ParallelIterator for Filter<I, P> |
| where |
| I: ParallelIterator, |
| P: Fn(&I::Item) -> bool + Sync + Send, |
| { |
| type Item = I::Item; |
| |
| fn drive_unindexed<C>(self, consumer: C) -> C::Result |
| where |
| C: UnindexedConsumer<Self::Item>, |
| { |
| let consumer1 = FilterConsumer::new(consumer, &self.filter_op); |
| self.base.drive_unindexed(consumer1) |
| } |
| } |
| |
| /// //////////////////////////////////////////////////////////////////////// |
| /// Consumer implementation |
| |
| struct FilterConsumer<'p, C, P: 'p> { |
| base: C, |
| filter_op: &'p P, |
| } |
| |
| impl<'p, C, P> FilterConsumer<'p, C, P> { |
| fn new(base: C, filter_op: &'p P) -> Self { |
| FilterConsumer { base, filter_op } |
| } |
| } |
| |
| impl<'p, T, C, P: 'p> Consumer<T> for FilterConsumer<'p, C, P> |
| where |
| C: Consumer<T>, |
| P: Fn(&T) -> bool + Sync, |
| { |
| type Folder = FilterFolder<'p, C::Folder, P>; |
| type Reducer = C::Reducer; |
| type Result = C::Result; |
| |
| fn split_at(self, index: usize) -> (Self, Self, C::Reducer) { |
| let (left, right, reducer) = self.base.split_at(index); |
| ( |
| FilterConsumer::new(left, self.filter_op), |
| FilterConsumer::new(right, self.filter_op), |
| reducer, |
| ) |
| } |
| |
| fn into_folder(self) -> Self::Folder { |
| FilterFolder { |
| base: self.base.into_folder(), |
| filter_op: self.filter_op, |
| } |
| } |
| |
| fn full(&self) -> bool { |
| self.base.full() |
| } |
| } |
| |
| impl<'p, T, C, P: 'p> UnindexedConsumer<T> for FilterConsumer<'p, C, P> |
| where |
| C: UnindexedConsumer<T>, |
| P: Fn(&T) -> bool + Sync, |
| { |
| fn split_off_left(&self) -> Self { |
| FilterConsumer::new(self.base.split_off_left(), &self.filter_op) |
| } |
| |
| fn to_reducer(&self) -> Self::Reducer { |
| self.base.to_reducer() |
| } |
| } |
| |
| struct FilterFolder<'p, C, P: 'p> { |
| base: C, |
| filter_op: &'p P, |
| } |
| |
| impl<'p, C, P, T> Folder<T> for FilterFolder<'p, C, P> |
| where |
| C: Folder<T>, |
| P: Fn(&T) -> bool + 'p, |
| { |
| type Result = C::Result; |
| |
| fn consume(self, item: T) -> Self { |
| let filter_op = self.filter_op; |
| if filter_op(&item) { |
| let base = self.base.consume(item); |
| FilterFolder { base, filter_op } |
| } else { |
| self |
| } |
| } |
| |
| // This cannot easily specialize `consume_iter` to be better than |
| // the default, because that requires checking `self.base.full()` |
| // during a call to `self.base.consume_iter()`. (#632) |
| |
| fn complete(self) -> Self::Result { |
| self.base.complete() |
| } |
| |
| fn full(&self) -> bool { |
| self.base.full() |
| } |
| } |