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)
}
}