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|
use super::plumbing::*;
use super::*;
/// `FlattenIter` turns each element to a serial iterator, then flattens these iterators
/// together. This struct is created by the [`flatten_iter()`] method on [`ParallelIterator`].
///
/// [`flatten_iter()`]: trait.ParallelIterator.html#method.flatten_iter
/// [`ParallelIterator`]: trait.ParallelIterator.html
#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
#[derive(Debug, Clone)]
pub struct FlattenIter<I: ParallelIterator> {
base: I,
}
impl<I> FlattenIter<I>
where
I: ParallelIterator,
I::Item: IntoIterator,
<I::Item as IntoIterator>::Item: Send,
{
/// Creates a new `FlattenIter` iterator.
pub(super) fn new(base: I) -> Self {
FlattenIter { base }
}
}
impl<I> ParallelIterator for FlattenIter<I>
where
I: ParallelIterator,
I::Item: IntoIterator,
<I::Item as IntoIterator>::Item: Send,
{
type Item = <I::Item as IntoIterator>::Item;
fn drive_unindexed<C>(self, consumer: C) -> C::Result
where
C: UnindexedConsumer<Self::Item>,
{
let consumer = FlattenIterConsumer::new(consumer);
self.base.drive_unindexed(consumer)
}
}
/// ////////////////////////////////////////////////////////////////////////
/// Consumer implementation
struct FlattenIterConsumer<C> {
base: C,
}
impl<C> FlattenIterConsumer<C> {
fn new(base: C) -> Self {
FlattenIterConsumer { base }
}
}
impl<T, C> Consumer<T> for FlattenIterConsumer<C>
where
C: UnindexedConsumer<T::Item>,
T: IntoIterator,
{
type Folder = FlattenIterFolder<C::Folder>;
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);
(
FlattenIterConsumer::new(left),
FlattenIterConsumer::new(right),
reducer,
)
}
fn into_folder(self) -> Self::Folder {
FlattenIterFolder {
base: self.base.into_folder(),
}
}
fn full(&self) -> bool {
self.base.full()
}
}
impl<T, C> UnindexedConsumer<T> for FlattenIterConsumer<C>
where
C: UnindexedConsumer<T::Item>,
T: IntoIterator,
{
fn split_off_left(&self) -> Self {
FlattenIterConsumer::new(self.base.split_off_left())
}
fn to_reducer(&self) -> Self::Reducer {
self.base.to_reducer()
}
}
struct FlattenIterFolder<C> {
base: C,
}
impl<T, C> Folder<T> for FlattenIterFolder<C>
where
C: Folder<T::Item>,
T: IntoIterator,
{
type Result = C::Result;
fn consume(self, item: T) -> Self {
let base = self.base.consume_iter(item);
FlattenIterFolder { base }
}
fn consume_iter<I>(self, iter: I) -> Self
where
I: IntoIterator<Item = T>,
{
let iter = iter.into_iter().flatten();
let base = self.base.consume_iter(iter);
FlattenIterFolder { base }
}
fn complete(self) -> Self::Result {
self.base.complete()
}
fn full(&self) -> bool {
self.base.full()
}
}
|
