multipart_write/write/
with.rs

1use crate::{FusedMultipartWrite, MultipartWrite};
2
3use futures_core::ready;
4use std::fmt::{self, Debug, Formatter};
5use std::pin::Pin;
6use std::task::{Context, Poll};
7
8pin_project_lite::pin_project! {
9    /// `MultipartWrite` for [`with`](super::MultipartWriteExt::with).
10    #[must_use = "futures do nothing unless polled"]
11    pub 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}
20
21impl<Wr, Part, U, Fut, F> With<Wr, Part, U, Fut, F>
22where
23    Wr: MultipartWrite<Part>,
24    F: FnMut(U) -> Fut,
25    Fut: Future,
26{
27    pub(super) fn new<E>(writer: Wr, f: F) -> Self
28    where
29        Fut: Future<Output = Result<Part, E>>,
30        E: From<Wr::Error>,
31    {
32        Self {
33            writer,
34            f,
35            future: None,
36            _f: std::marker::PhantomData,
37        }
38    }
39
40    /// Acquires a reference to the underlying writer.
41    pub fn get_ref(&self) -> &Wr {
42        &self.writer
43    }
44
45    /// Acquires a mutable reference to the underlying writer.
46    ///
47    /// It is inadvisable to directly write to the underlying writer.
48    pub fn get_mut(&mut self) -> &mut Wr {
49        &mut self.writer
50    }
51
52    /// Acquires a pinned mutable reference to the underlying writer.
53    ///
54    /// It is inadvisable to directly write to the underlying writer.
55    pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut Wr> {
56        self.project().writer
57    }
58}
59
60impl<Wr, Part, U, Fut, F, E> With<Wr, Part, U, Fut, F>
61where
62    Wr: MultipartWrite<Part>,
63    F: FnMut(U) -> Fut,
64    Fut: Future<Output = Result<Part, E>>,
65    E: From<Wr::Error>,
66{
67    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), E>> {
68        let mut this = self.project();
69
70        let part = match this.future.as_mut().as_pin_mut() {
71            None => return Poll::Ready(Ok(())),
72            Some(fut) => ready!(fut.poll(cx))?,
73        };
74        this.future.set(None);
75        this.writer.start_send(part)?;
76        Poll::Ready(Ok(()))
77    }
78}
79
80impl<Wr, Part, U, Fut, F, E> FusedMultipartWrite<U> for With<Wr, Part, U, Fut, F>
81where
82    Wr: FusedMultipartWrite<Part>,
83    F: FnMut(U) -> Fut,
84    Fut: Future<Output = Result<Part, E>>,
85    E: From<Wr::Error>,
86{
87    fn is_terminated(&self) -> bool {
88        self.writer.is_terminated()
89    }
90}
91
92impl<Wr, Part, U, Fut, F, E> MultipartWrite<U> for With<Wr, Part, U, Fut, F>
93where
94    Wr: MultipartWrite<Part>,
95    F: FnMut(U) -> Fut,
96    Fut: Future<Output = Result<Part, E>>,
97    E: From<Wr::Error>,
98{
99    type Ret = ();
100    type Output = Wr::Output;
101    type Error = E;
102
103    fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
104        ready!(self.as_mut().poll(cx))?;
105        ready!(self.project().writer.poll_ready(cx)?);
106        Poll::Ready(Ok(()))
107    }
108
109    fn start_send(self: Pin<&mut Self>, part: U) -> Result<Self::Ret, Self::Error> {
110        let mut this = self.project();
111        this.future.set(Some((this.f)(part)));
112        Ok(())
113    }
114
115    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
116        ready!(self.as_mut().poll(cx))?;
117        ready!(self.project().writer.poll_flush(cx)?);
118        Poll::Ready(Ok(()))
119    }
120
121    fn poll_complete(
122        mut self: Pin<&mut Self>,
123        cx: &mut Context<'_>,
124    ) -> Poll<Result<Self::Output, Self::Error>> {
125        ready!(self.as_mut().poll(cx))?;
126        let ret = ready!(self.project().writer.poll_complete(cx)?);
127        Poll::Ready(Ok(ret))
128    }
129}
130
131impl<Wr, Part, U, Fut, F> Debug for With<Wr, Part, U, Fut, F>
132where
133    Wr: Debug,
134    Fut: Debug,
135{
136    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
137        f.debug_struct("With")
138            .field("writer", &self.writer)
139            .field("f", &"F")
140            .field("future", &self.future)
141            .finish()
142    }
143}
multipart_write/write/with.rs

multipart_write/write/
with.rs
