summaryrefslogtreecommitdiffstats
path: root/vendor/tokio-util/src/compat.rs
blob: 6a8802d96995e76f1fa94d29dbc5e98301aed1a2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
//! Compatibility between the `tokio::io` and `futures-io` versions of the
//! `AsyncRead` and `AsyncWrite` traits.
use futures_core::ready;
use pin_project_lite::pin_project;
use std::io;
use std::pin::Pin;
use std::task::{Context, Poll};

pin_project! {
    /// A compatibility layer that allows conversion between the
    /// `tokio::io` and `futures-io` `AsyncRead` and `AsyncWrite` traits.
    #[derive(Copy, Clone, Debug)]
    pub struct Compat<T> {
        #[pin]
        inner: T,
        seek_pos: Option<io::SeekFrom>,
    }
}

/// Extension trait that allows converting a type implementing
/// `futures_io::AsyncRead` to implement `tokio::io::AsyncRead`.
pub trait FuturesAsyncReadCompatExt: futures_io::AsyncRead {
    /// Wraps `self` with a compatibility layer that implements
    /// `tokio_io::AsyncRead`.
    fn compat(self) -> Compat<Self>
    where
        Self: Sized,
    {
        Compat::new(self)
    }
}

impl<T: futures_io::AsyncRead> FuturesAsyncReadCompatExt for T {}

/// Extension trait that allows converting a type implementing
/// `futures_io::AsyncWrite` to implement `tokio::io::AsyncWrite`.
pub trait FuturesAsyncWriteCompatExt: futures_io::AsyncWrite {
    /// Wraps `self` with a compatibility layer that implements
    /// `tokio::io::AsyncWrite`.
    fn compat_write(self) -> Compat<Self>
    where
        Self: Sized,
    {
        Compat::new(self)
    }
}

impl<T: futures_io::AsyncWrite> FuturesAsyncWriteCompatExt for T {}

/// Extension trait that allows converting a type implementing
/// `tokio::io::AsyncRead` to implement `futures_io::AsyncRead`.
pub trait TokioAsyncReadCompatExt: tokio::io::AsyncRead {
    /// Wraps `self` with a compatibility layer that implements
    /// `futures_io::AsyncRead`.
    fn compat(self) -> Compat<Self>
    where
        Self: Sized,
    {
        Compat::new(self)
    }
}

impl<T: tokio::io::AsyncRead> TokioAsyncReadCompatExt for T {}

/// Extension trait that allows converting a type implementing
/// `tokio::io::AsyncWrite` to implement `futures_io::AsyncWrite`.
pub trait TokioAsyncWriteCompatExt: tokio::io::AsyncWrite {
    /// Wraps `self` with a compatibility layer that implements
    /// `futures_io::AsyncWrite`.
    fn compat_write(self) -> Compat<Self>
    where
        Self: Sized,
    {
        Compat::new(self)
    }
}

impl<T: tokio::io::AsyncWrite> TokioAsyncWriteCompatExt for T {}

// === impl Compat ===

impl<T> Compat<T> {
    fn new(inner: T) -> Self {
        Self {
            inner,
            seek_pos: None,
        }
    }

    /// Get a reference to the `Future`, `Stream`, `AsyncRead`, or `AsyncWrite` object
    /// contained within.
    pub fn get_ref(&self) -> &T {
        &self.inner
    }

    /// Get a mutable reference to the `Future`, `Stream`, `AsyncRead`, or `AsyncWrite` object
    /// contained within.
    pub fn get_mut(&mut self) -> &mut T {
        &mut self.inner
    }

    /// Returns the wrapped item.
    pub fn into_inner(self) -> T {
        self.inner
    }
}

impl<T> tokio::io::AsyncRead for Compat<T>
where
    T: futures_io::AsyncRead,
{
    fn poll_read(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &mut tokio::io::ReadBuf<'_>,
    ) -> Poll<io::Result<()>> {
        // We can't trust the inner type to not peak at the bytes,
        // so we must defensively initialize the buffer.
        let slice = buf.initialize_unfilled();
        let n = ready!(futures_io::AsyncRead::poll_read(
            self.project().inner,
            cx,
            slice
        ))?;
        buf.advance(n);
        Poll::Ready(Ok(()))
    }
}

impl<T> futures_io::AsyncRead for Compat<T>
where
    T: tokio::io::AsyncRead,
{
    fn poll_read(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        slice: &mut [u8],
    ) -> Poll<io::Result<usize>> {
        let mut buf = tokio::io::ReadBuf::new(slice);
        ready!(tokio::io::AsyncRead::poll_read(
            self.project().inner,
            cx,
            &mut buf
        ))?;
        Poll::Ready(Ok(buf.filled().len()))
    }
}

impl<T> tokio::io::AsyncBufRead for Compat<T>
where
    T: futures_io::AsyncBufRead,
{
    fn poll_fill_buf<'a>(
        self: Pin<&'a mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<io::Result<&'a [u8]>> {
        futures_io::AsyncBufRead::poll_fill_buf(self.project().inner, cx)
    }

    fn consume(self: Pin<&mut Self>, amt: usize) {
        futures_io::AsyncBufRead::consume(self.project().inner, amt)
    }
}

impl<T> futures_io::AsyncBufRead for Compat<T>
where
    T: tokio::io::AsyncBufRead,
{
    fn poll_fill_buf<'a>(
        self: Pin<&'a mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<io::Result<&'a [u8]>> {
        tokio::io::AsyncBufRead::poll_fill_buf(self.project().inner, cx)
    }

    fn consume(self: Pin<&mut Self>, amt: usize) {
        tokio::io::AsyncBufRead::consume(self.project().inner, amt)
    }
}

impl<T> tokio::io::AsyncWrite for Compat<T>
where
    T: futures_io::AsyncWrite,
{
    fn poll_write(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &[u8],
    ) -> Poll<io::Result<usize>> {
        futures_io::AsyncWrite::poll_write(self.project().inner, cx, buf)
    }

    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
        futures_io::AsyncWrite::poll_flush(self.project().inner, cx)
    }

    fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
        futures_io::AsyncWrite::poll_close(self.project().inner, cx)
    }
}

impl<T> futures_io::AsyncWrite for Compat<T>
where
    T: tokio::io::AsyncWrite,
{
    fn poll_write(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &[u8],
    ) -> Poll<io::Result<usize>> {
        tokio::io::AsyncWrite::poll_write(self.project().inner, cx, buf)
    }

    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
        tokio::io::AsyncWrite::poll_flush(self.project().inner, cx)
    }

    fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
        tokio::io::AsyncWrite::poll_shutdown(self.project().inner, cx)
    }
}

impl<T: tokio::io::AsyncSeek> futures_io::AsyncSeek for Compat<T> {
    fn poll_seek(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        pos: io::SeekFrom,
    ) -> Poll<io::Result<u64>> {
        if self.seek_pos != Some(pos) {
            self.as_mut().project().inner.start_seek(pos)?;
            *self.as_mut().project().seek_pos = Some(pos);
        }
        let res = ready!(self.as_mut().project().inner.poll_complete(cx));
        *self.as_mut().project().seek_pos = None;
        Poll::Ready(res.map(|p| p as u64))
    }
}

impl<T: futures_io::AsyncSeek> tokio::io::AsyncSeek for Compat<T> {
    fn start_seek(mut self: Pin<&mut Self>, pos: io::SeekFrom) -> io::Result<()> {
        *self.as_mut().project().seek_pos = Some(pos);
        Ok(())
    }

    fn poll_complete(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<u64>> {
        let pos = match self.seek_pos {
            None => {
                // tokio 1.x AsyncSeek recommends calling poll_complete before start_seek.
                // We don't have to guarantee that the value returned by
                // poll_complete called without start_seek is correct,
                // so we'll return 0.
                return Poll::Ready(Ok(0));
            }
            Some(pos) => pos,
        };
        let res = ready!(self.as_mut().project().inner.poll_seek(cx, pos));
        *self.as_mut().project().seek_pos = None;
        Poll::Ready(res.map(|p| p as u64))
    }
}

#[cfg(unix)]
impl<T: std::os::unix::io::AsRawFd> std::os::unix::io::AsRawFd for Compat<T> {
    fn as_raw_fd(&self) -> std::os::unix::io::RawFd {
        self.inner.as_raw_fd()
    }
}

#[cfg(windows)]
impl<T: std::os::windows::io::AsRawHandle> std::os::windows::io::AsRawHandle for Compat<T> {
    fn as_raw_handle(&self) -> std::os::windows::io::RawHandle {
        self.inner.as_raw_handle()
    }
}