| use super::plumbing::*; |
| use super::*; |
| |
| use std::fmt::{self, Debug}; |
| |
| /// `FilterMap` creates an iterator that uses `filter_op` to both filter and map elements. |
| /// This struct is created by the [`filter_map()`] method on [`ParallelIterator`]. |
| /// |
| /// [`filter_map()`]: trait.ParallelIterator.html#method.filter_map |
| /// [`ParallelIterator`]: trait.ParallelIterator.html |
| #[must_use = "iterator adaptors are lazy and do nothing unless consumed"] |
| #[derive(Clone)] |
| pub struct FilterMap<I: ParallelIterator, P> { |
| base: I, |
| filter_op: P, |
| } |
| |
| impl<I: ParallelIterator + Debug, P> Debug for FilterMap<I, P> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.debug_struct("FilterMap") |
| .field("base", &self.base) |
| .finish() |
| } |
| } |
| |
| impl<I: ParallelIterator, P> FilterMap<I, P> { |
| /// Creates a new `FilterMap` iterator. |
| pub(super) fn new(base: I, filter_op: P) -> Self { |
| FilterMap { base, filter_op } |
| } |
| } |
| |
| impl<I, P, R> ParallelIterator for FilterMap<I, P> |
| where |
| I: ParallelIterator, |
| P: Fn(I::Item) -> Option<R> + Sync + Send, |
| R: Send, |
| { |
| type Item = R; |
| |
| fn drive_unindexed<C>(self, consumer: C) -> C::Result |
| where |
| C: UnindexedConsumer<Self::Item>, |
| { |
| let consumer = FilterMapConsumer::new(consumer, &self.filter_op); |
| self.base.drive_unindexed(consumer) |
| } |
| } |
| |
| /// //////////////////////////////////////////////////////////////////////// |
| /// Consumer implementation |
| |
| struct FilterMapConsumer<'p, C, P> { |
| base: C, |
| filter_op: &'p P, |
| } |
| |
| impl<'p, C, P: 'p> FilterMapConsumer<'p, C, P> { |
| fn new(base: C, filter_op: &'p P) -> Self { |
| FilterMapConsumer { base, filter_op } |
| } |
| } |
| |
| impl<'p, T, U, C, P> Consumer<T> for FilterMapConsumer<'p, C, P> |
| where |
| C: Consumer<U>, |
| P: Fn(T) -> Option<U> + Sync + 'p, |
| { |
| type Folder = FilterMapFolder<'p, C::Folder, P>; |
| 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); |
| ( |
| FilterMapConsumer::new(left, self.filter_op), |
| FilterMapConsumer::new(right, self.filter_op), |
| reducer, |
| ) |
| } |
| |
| fn into_folder(self) -> Self::Folder { |
| let base = self.base.into_folder(); |
| FilterMapFolder { |
| base, |
| filter_op: self.filter_op, |
| } |
| } |
| |
| fn full(&self) -> bool { |
| self.base.full() |
| } |
| } |
| |
| impl<'p, T, U, C, P> UnindexedConsumer<T> for FilterMapConsumer<'p, C, P> |
| where |
| C: UnindexedConsumer<U>, |
| P: Fn(T) -> Option<U> + Sync + 'p, |
| { |
| fn split_off_left(&self) -> Self { |
| FilterMapConsumer::new(self.base.split_off_left(), self.filter_op) |
| } |
| |
| fn to_reducer(&self) -> Self::Reducer { |
| self.base.to_reducer() |
| } |
| } |
| |
| struct FilterMapFolder<'p, C, P> { |
| base: C, |
| filter_op: &'p P, |
| } |
| |
| impl<'p, T, U, C, P> Folder<T> for FilterMapFolder<'p, C, P> |
| where |
| C: Folder<U>, |
| P: Fn(T) -> Option<U> + Sync + 'p, |
| { |
| type Result = C::Result; |
| |
| fn consume(self, item: T) -> Self { |
| let filter_op = self.filter_op; |
| if let Some(mapped_item) = filter_op(item) { |
| let base = self.base.consume(mapped_item); |
| FilterMapFolder { 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) -> C::Result { |
| self.base.complete() |
| } |
| |
| fn full(&self) -> bool { |
| self.base.full() |
| } |
| } |