async_native_tls/
std_adapter.rs

1use std::io::{self, Read, Write};
2use std::marker::Unpin;
3use std::pin::Pin;
4use std::task::{Context, Poll};
5
6use crate::runtime::{AsyncRead, AsyncWrite};
7
8#[derive(Debug)]
9pub(crate) struct StdAdapter<S> {
10    pub(crate) inner: S,
11    pub(crate) context: *mut (),
12}
13
14// *mut () context is neither Send nor Sync
15unsafe impl<S: Send> Send for StdAdapter<S> {}
16unsafe impl<S: Sync> Sync for StdAdapter<S> {}
17
18impl<S> StdAdapter<S>
19where
20    S: Unpin,
21{
22    pub(crate) fn with_context<F, R>(&mut self, f: F) -> R
23    where
24        F: FnOnce(&mut Context<'_>, Pin<&mut S>) -> R,
25    {
26        unsafe {
27            assert!(!self.context.is_null());
28            let waker = &mut *(self.context as *mut _);
29            f(waker, Pin::new(&mut self.inner))
30        }
31    }
32}
33
34#[cfg(feature = "runtime-async-std")]
35impl<S> Read for StdAdapter<S>
36where
37    S: AsyncRead + Unpin,
38{
39    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
40        match self.with_context(|ctx, stream| stream.poll_read(ctx, buf)) {
41            Poll::Ready(r) => r,
42            Poll::Pending => Err(io::Error::from(io::ErrorKind::WouldBlock)),
43        }
44    }
45}
46
47#[cfg(feature = "runtime-tokio")]
48impl<S> Read for StdAdapter<S>
49where
50    S: AsyncRead + Unpin,
51{
52    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
53        let mut buf = tokio::io::ReadBuf::new(buf);
54        match self.with_context(|ctx, stream| stream.poll_read(ctx, &mut buf)) {
55            Poll::Ready(r) => r.map(|_| buf.filled().len()),
56            Poll::Pending => Err(io::Error::from(io::ErrorKind::WouldBlock)),
57        }
58    }
59}
60
61impl<S> Write for StdAdapter<S>
62where
63    S: AsyncWrite + Unpin,
64{
65    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
66        match self.with_context(|ctx, stream| stream.poll_write(ctx, buf)) {
67            Poll::Ready(r) => r,
68            Poll::Pending => Err(io::Error::from(io::ErrorKind::WouldBlock)),
69        }
70    }
71
72    fn flush(&mut self) -> io::Result<()> {
73        match self.with_context(|ctx, stream| stream.poll_flush(ctx)) {
74            Poll::Ready(r) => r,
75            Poll::Pending => Err(io::Error::from(io::ErrorKind::WouldBlock)),
76        }
77    }
78}
async_native_tls/std_adapter.rs

async_native_tls/
std_adapter.rs
