third_party/rust_crates/vendor/tokio-rustls/src/common/handshake.rs

use crate::common::{Stream, TlsState};
use futures_core::future::FusedFuture;
use rustls::Session;
use std::future::Future;
use std::pin::Pin;
use std::task::{Context, Poll};
use std::{io, mem};
use tokio::io::{AsyncRead, AsyncWrite};

pub(crate) trait IoSession {
    type Io;
    type Session;

    fn skip_handshake(&self) -> bool;
    fn get_mut(&mut self) -> (&mut TlsState, &mut Self::Io, &mut Self::Session);
    fn into_io(self) -> Self::Io;
}

pub(crate) enum MidHandshake<IS> {
    Handshaking(IS),
    End,
}

impl<IS> FusedFuture for MidHandshake<IS>
where
    IS: IoSession + Unpin,
    IS::Io: AsyncRead + AsyncWrite + Unpin,
    IS::Session: Session + Unpin,
{
    fn is_terminated(&self) -> bool {
        if let MidHandshake::End = self {
            true
        } else {
            false
        }
    }
}

impl<IS> Future for MidHandshake<IS>
where
    IS: IoSession + Unpin,
    IS::Io: AsyncRead + AsyncWrite + Unpin,
    IS::Session: Session + Unpin,
{
    type Output = Result<IS, (io::Error, IS::Io)>;

    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        let this = self.get_mut();

        if let MidHandshake::Handshaking(mut stream) = mem::replace(this, MidHandshake::End) {
            if !stream.skip_handshake() {
                let (state, io, session) = stream.get_mut();
                let mut tls_stream = Stream::new(io, session).set_eof(!state.readable());

                macro_rules! try_poll {
                    ( $e:expr ) => {
                        match $e {
                            Poll::Ready(Ok(_)) => (),
                            Poll::Ready(Err(err)) => {
                                return Poll::Ready(Err((err, stream.into_io())))
                            }
                            Poll::Pending => {
                                *this = MidHandshake::Handshaking(stream);
                                return Poll::Pending;
                            }
                        }
                    };
                }

                while tls_stream.session.is_handshaking() {
                    try_poll!(tls_stream.handshake(cx));
                }

                while tls_stream.session.wants_write() {
                    try_poll!(tls_stream.write_io(cx));
                }
            }

            Poll::Ready(Ok(stream))
        } else {
            panic!("unexpected polling after handshake")
        }
    }
}