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use derive_new::new; use futures::{pin_mut, Stream}; use pin_project::pin_project; use serde::{Deserialize, Serialize}; use std::{ pin::Pin, task::{Context, Poll} }; use super::{ParallelPipe, ParallelStream, PipeTask, PipeTaskAsync, StreamTask, StreamTaskAsync}; use crate::sink::{Sink, SinkMap}; #[derive(new)] #[must_use] pub struct Map<I, F> { i: I, f: F, } impl_par_dist! { impl<I: ParallelStream, F, R> ParallelStream for Map<I, F> where F: FnMut(I::Item) -> R + Clone + Send + 'static, { type Item = R; type Task = MapTask<I::Task, F>; fn size_hint(&self) -> (usize, Option<usize>) { self.i.size_hint() } fn next_task(&mut self) -> Option<Self::Task> { self.i.next_task().map(|task| { let f = self.f.clone(); MapTask { task, f } }) } } impl<I: ParallelPipe<Source>, F, R, Source> ParallelPipe<Source> for Map<I, F> where F: FnMut(<I as ParallelPipe<Source>>::Item) -> R + Clone + Send + 'static, { type Item = R; type Task = MapTask<I::Task, F>; fn task(&self) -> Self::Task { let task = self.i.task(); let f = self.f.clone(); MapTask { task, f } } } } #[pin_project] #[derive(Serialize, Deserialize)] pub struct MapTask<C, F> { #[pin] task: C, f: F, } impl<C: StreamTask, F, R> StreamTask for MapTask<C, F> where F: FnMut(C::Item) -> R + Clone, { type Item = R; type Async = MapTask<C::Async, F>; fn into_async(self) -> Self::Async { MapTask { task: self.task.into_async(), f: self.f, } } } impl<C: PipeTask<Source>, F, R, Source> PipeTask<Source> for MapTask<C, F> where F: FnMut(C::Item) -> R + Clone, { type Item = R; type Async = MapTask<C::Async, F>; fn into_async(self) -> Self::Async { MapTask { task: self.task.into_async(), f: self.f, } } } impl<C: StreamTaskAsync, F, R> StreamTaskAsync for MapTask<C, F> where F: FnMut(C::Item) -> R + Clone, { type Item = R; fn poll_run( self: Pin<&mut Self>, cx: &mut Context, sink: Pin<&mut impl Sink<Item = Self::Item>>, ) -> Poll<()> { let mut self_ = self.project(); let (task, f) = (self_.task, &mut self_.f); let sink = SinkMap::new(sink, |item| f(item)); pin_mut!(sink); task.poll_run(cx, sink) } } impl<C: PipeTaskAsync<Source>, F, R, Source> PipeTaskAsync<Source> for MapTask<C, F> where F: FnMut(<C as PipeTaskAsync<Source>>::Item) -> R + Clone, { type Item = R; fn poll_run( self: Pin<&mut Self>, cx: &mut Context, stream: Pin<&mut impl Stream<Item = Source>>, sink: Pin<&mut impl Sink<Item = Self::Item>>, ) -> Poll<()> { let mut self_ = self.project(); let (task, f) = (self_.task, &mut self_.f); let sink = SinkMap::new(sink, |item| f(item)); pin_mut!(sink); task.poll_run(cx, stream, sink) } }