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

multipart_write/write/
then.rs
