Source code
Revision control
Copy as Markdown
Other Tools
//! The `Accept` trait and supporting types.
//!
//! This module contains:
//!
//! - The [`Accept`](Accept) trait used to asynchronously accept incoming
//! connections.
//! - Utilities like `poll_fn` to ease creating a custom `Accept`.
#[cfg(feature = "stream")]
use futures_core::Stream;
#[cfg(feature = "stream")]
use pin_project_lite::pin_project;
use crate::common::{
task::{self, Poll},
Pin,
};
/// Asynchronously accept incoming connections.
pub trait Accept {
/// The connection type that can be accepted.
type Conn;
/// The error type that can occur when accepting a connection.
type Error;
/// Poll to accept the next connection.
fn poll_accept(
self: Pin<&mut Self>,
cx: &mut task::Context<'_>,
) -> Poll<Option<Result<Self::Conn, Self::Error>>>;
}
/// Create an `Accept` with a polling function.
///
/// # Example
///
/// ```
/// use std::task::Poll;
/// use hyper::server::{accept, Server};
///
/// # let mock_conn = ();
/// // If we created some mocked connection...
/// let mut conn = Some(mock_conn);
///
/// // And accept just the mocked conn once...
/// let once = accept::poll_fn(move |cx| {
/// Poll::Ready(conn.take().map(Ok::<_, ()>))
/// });
///
/// let builder = Server::builder(once);
/// ```
pub fn poll_fn<F, IO, E>(func: F) -> impl Accept<Conn = IO, Error = E>
where
F: FnMut(&mut task::Context<'_>) -> Poll<Option<Result<IO, E>>>,
{
struct PollFn<F>(F);
// The closure `F` is never pinned
impl<F> Unpin for PollFn<F> {}
impl<F, IO, E> Accept for PollFn<F>
where
F: FnMut(&mut task::Context<'_>) -> Poll<Option<Result<IO, E>>>,
{
type Conn = IO;
type Error = E;
fn poll_accept(
self: Pin<&mut Self>,
cx: &mut task::Context<'_>,
) -> Poll<Option<Result<Self::Conn, Self::Error>>> {
(self.get_mut().0)(cx)
}
}
PollFn(func)
}
/// Adapt a `Stream` of incoming connections into an `Accept`.
///
/// # Optional
///
/// This function requires enabling the `stream` feature in your
/// `Cargo.toml`.
#[cfg(feature = "stream")]
pub fn from_stream<S, IO, E>(stream: S) -> impl Accept<Conn = IO, Error = E>
where
S: Stream<Item = Result<IO, E>>,
{
pin_project! {
struct FromStream<S> {
#[pin]
stream: S,
}
}
impl<S, IO, E> Accept for FromStream<S>
where
S: Stream<Item = Result<IO, E>>,
{
type Conn = IO;
type Error = E;
fn poll_accept(
self: Pin<&mut Self>,
cx: &mut task::Context<'_>,
) -> Poll<Option<Result<Self::Conn, Self::Error>>> {
self.project().stream.poll_next(cx)
}
}
FromStream { stream }
}