multipart_write/write/
with.rs

1use crate::{FusedMultipartWrite, MultipartWrite};
2
3use futures::ready;
4use std::fmt::{self, Debug, Formatter};
5use std::pin::Pin;
6use std::task::{Context, Poll};
7
8/// `MultipartWrite` for [`with`](super::MultipartWriteExt::with).
9#[must_use = "futures do nothing unless polled"]
10#[pin_project::pin_project]
11pub struct With<Wr, Part, U, Fut, F> {
12    #[pin]
13    writer: Wr,
14    f: F,
15    #[pin]
16    future: Option<Fut>,
17    _f: std::marker::PhantomData<fn(U) -> Part>,
18}
19
20impl<Wr, Part, U, Fut, F> With<Wr, Part, U, Fut, F>
21where
22    Wr: MultipartWrite<Part>,
23    F: FnMut(U) -> Fut,
24    Fut: Future,
25{
26    pub(super) fn new<E>(writer: Wr, f: F) -> Self
27    where
28        Fut: Future<Output = Result<Part, E>>,
29        E: From<Wr::Error>,
30    {
31        Self {
32            writer,
33            f,
34            future: None,
35            _f: std::marker::PhantomData,
36        }
37    }
38
39    /// Acquires a reference to the underlying writer.
40    pub fn get_ref(&self) -> &Wr {
41        &self.writer
42    }
43
44    /// Acquires a mutable reference to the underlying writer.
45    ///
46    /// It is inadvisable to directly write to the underlying writer.
47    pub fn get_mut(&mut self) -> &mut Wr {
48        &mut self.writer
49    }
50
51    /// Acquires a pinned mutable reference to the underlying writer.
52    ///
53    /// It is inadvisable to directly write to the underlying writer.
54    pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut Wr> {
55        self.project().writer
56    }
57}
58
59impl<Wr, Part, U, Fut, F, E> With<Wr, Part, U, Fut, F>
60where
61    Wr: MultipartWrite<Part>,
62    F: FnMut(U) -> Fut,
63    Fut: Future<Output = Result<Part, E>>,
64    E: From<Wr::Error>,
65{
66    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), E>> {
67        let mut this = self.project();
68
69        let part = match this.future.as_mut().as_pin_mut() {
70            None => return Poll::Ready(Ok(())),
71            Some(fut) => ready!(fut.poll(cx))?,
72        };
73        this.future.set(None);
74        this.writer.start_send(part)?;
75        Poll::Ready(Ok(()))
76    }
77}
78
79impl<Wr, Part, U, Fut, F, E> FusedMultipartWrite<U> for With<Wr, Part, U, Fut, F>
80where
81    Wr: FusedMultipartWrite<Part>,
82    F: FnMut(U) -> Fut,
83    Fut: Future<Output = Result<Part, E>>,
84    E: From<Wr::Error>,
85{
86    fn is_terminated(&self) -> bool {
87        self.writer.is_terminated()
88    }
89}
90
91impl<Wr, Part, U, Fut, F, E> MultipartWrite<U> for With<Wr, Part, U, Fut, F>
92where
93    Wr: MultipartWrite<Part>,
94    F: FnMut(U) -> Fut,
95    Fut: Future<Output = Result<Part, E>>,
96    E: From<Wr::Error>,
97{
98    type Ret = ();
99    type Output = Wr::Output;
100    type Error = E;
101
102    fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
103        ready!(self.as_mut().poll(cx))?;
104        ready!(self.project().writer.poll_ready(cx)?);
105        Poll::Ready(Ok(()))
106    }
107
108    fn start_send(self: Pin<&mut Self>, part: U) -> Result<Self::Ret, Self::Error> {
109        let mut this = self.project();
110        this.future.set(Some((this.f)(part)));
111        Ok(())
112    }
113
114    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
115        ready!(self.as_mut().poll(cx))?;
116        ready!(self.project().writer.poll_flush(cx)?);
117        Poll::Ready(Ok(()))
118    }
119
120    fn poll_complete(
121        mut self: Pin<&mut Self>,
122        cx: &mut Context<'_>,
123    ) -> Poll<Result<Self::Output, Self::Error>> {
124        ready!(self.as_mut().poll(cx))?;
125        let ret = ready!(self.project().writer.poll_complete(cx)?);
126        Poll::Ready(Ok(ret))
127    }
128}
129
130impl<Wr, Part, U, Fut, F> Debug for With<Wr, Part, U, Fut, F>
131where
132    Wr: Debug,
133    Fut: Debug,
134{
135    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
136        f.debug_struct("With")
137            .field("writer", &self.writer)
138            .field("future", &self.future)
139            .finish()
140    }
141}
multipart_write/write/with.rs

multipart_write/write/
with.rs
