actix-web/src/client/pipeline.rs

use std::collections::VecDeque;

use actix_net::codec::Framed;
use actix_net::service::Service;
use bytes::Bytes;
use futures::future::{err, ok, Either};
use futures::{Async, Future, Poll, Sink, Stream};
use tokio_io::{AsyncRead, AsyncWrite};

use super::error::{ConnectorError, SendRequestError};
use super::request::RequestHead;
use super::response::ClientResponse;
use super::{Connect, Connection};
use body::{BodyStream, BodyType, MessageBody};
use error::Error;
use h1;

pub fn send_request<T, Io, B>(
    head: RequestHead,
    body: B,
    connector: &mut T,
) -> impl Future<Item = ClientResponse, Error = SendRequestError>
where
    T: Service<Request = Connect, Response = Connection<Io>, Error = ConnectorError>,
    B: MessageBody,
    Io: AsyncRead + AsyncWrite + 'static,
{
    let tp = body.tp();

    connector
        .call(Connect::new(head.uri.clone()))
        .from_err()
        .map(|io| Framed::new(io, h1::ClientCodec::default()))
        .and_then(|framed| framed.send((head, tp).into()).from_err())
        .and_then(move |framed| match body.tp() {
            BodyType::None | BodyType::Zero => Either::A(ok(framed)),
            _ => Either::B(SendBody::new(body, framed)),
        }).and_then(|framed| {
            framed
                .into_future()
                .map_err(|(e, _)| SendRequestError::from(e))
                .and_then(|(item, framed)| {
                    if let Some(item) = item {
                        let mut res = item.into_item().unwrap();
                        match framed.get_codec().message_type() {
                            h1::MessageType::None => release_connection(framed),
                            _ => res.payload = Some(Payload::stream(framed)),
                        }
                        ok(res)
                    } else {
                        err(ConnectorError::Disconnected.into())
                    }
                })
        })
}

struct SendBody<Io, B> {
    body: Option<B>,
    framed: Option<Framed<Connection<Io>, h1::ClientCodec>>,
    write_buf: VecDeque<h1::Message<(RequestHead, BodyType)>>,
    flushed: bool,
}

impl<Io, B> SendBody<Io, B>
where
    Io: AsyncRead + AsyncWrite + 'static,
    B: MessageBody,
{
    fn new(body: B, framed: Framed<Connection<Io>, h1::ClientCodec>) -> Self {
        SendBody {
            body: Some(body),
            framed: Some(framed),
            write_buf: VecDeque::new(),
            flushed: true,
        }
    }
}

impl<Io, B> Future for SendBody<Io, B>
where
    Io: AsyncRead + AsyncWrite + 'static,
    B: MessageBody,
{
    type Item = Framed<Connection<Io>, h1::ClientCodec>;
    type Error = SendRequestError;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        let mut body_ready = true;
        loop {
            while body_ready
                && self.body.is_some()
                && !self.framed.as_ref().unwrap().is_write_buf_full()
            {
                match self.body.as_mut().unwrap().poll_next()? {
                    Async::Ready(None) => {
                        self.flushed = false;
                        self.framed
                            .as_mut()
                            .unwrap()
                            .start_send(h1::Message::Chunk(None))?;
                        break;
                    }
                    Async::Ready(Some(chunk)) => {
                        self.flushed = false;
                        self.framed
                            .as_mut()
                            .unwrap()
                            .start_send(h1::Message::Chunk(Some(chunk)))?;
                    }
                    Async::NotReady => body_ready = false,
                }
            }

            if !self.flushed {
                match self.framed.as_mut().unwrap().poll_complete()? {
                    Async::Ready(_) => {
                        self.flushed = true;
                        continue;
                    }
                    Async::NotReady => return Ok(Async::NotReady),
                }
            }

            if self.body.is_none() {
                return Ok(Async::Ready(self.framed.take().unwrap()));
            }
            return Ok(Async::NotReady);
        }
    }
}

struct Payload<Io> {
    framed: Option<Framed<Connection<Io>, h1::ClientCodec>>,
}

impl<Io: AsyncRead + AsyncWrite + 'static> Payload<Io> {
    fn stream(framed: Framed<Connection<Io>, h1::ClientCodec>) -> BodyStream {
        Box::new(Payload {
            framed: Some(framed),
        })
    }
}

impl<Io: AsyncRead + AsyncWrite + 'static> Stream for Payload<Io> {
    type Item = Bytes;
    type Error = Error;

    fn poll(&mut self) -> Poll<Option<Self::Item>, Error> {
        match self.framed.as_mut().unwrap().poll()? {
            Async::NotReady => Ok(Async::NotReady),
            Async::Ready(Some(chunk)) => match chunk {
                h1::Message::Chunk(Some(chunk)) => Ok(Async::Ready(Some(chunk))),
                h1::Message::Chunk(None) => {
                    release_connection(self.framed.take().unwrap());
                    Ok(Async::Ready(None))
                }
                h1::Message::Item(_) => unreachable!(),
            },
            Async::Ready(None) => Ok(Async::Ready(None)),
        }
    }
}

fn release_connection<Io>(framed: Framed<Connection<Io>, h1::ClientCodec>)
where
    Io: AsyncRead + AsyncWrite + 'static,
{
    let parts = framed.into_parts();
    if parts.read_buf.is_empty() && parts.write_buf.is_empty() {
        parts.io.release()
    } else {
        parts.io.close()
    }
}