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

//! Utilities for working with the traits from the
//! [async-codec](https://crates.io/crates/async-codec) crate.
#![deny(missing_docs)]

extern crate async_codec;
#[macro_use(try_ready)]
extern crate futures_core;
extern crate futures_io;
extern crate futures_executor;
extern crate futures_util;

pub mod encoder;
pub mod decoder;
pub mod testing;

use async_codec::{AsyncEncode, AsyncEncodeLen, AsyncDecode, DecodeError};
use futures_core::{Future, Poll};
use futures_core::Async::{Ready, Pending};
use futures_core::task::Context;
use futures_io::{AsyncRead, AsyncWrite, Error as FutIoErr};

/// Encode a value into an `AsyncWrite`, using an `AsyncEncode`.
pub fn encode<W, C>(writer: W, co: C) -> Encoder<W, C> {
    Encoder::new(writer, co)
}

/// Future for fully encoding an `AsyncEncode` into an `AsyncWrite`.
pub struct Encoder<W, C> {
    writer: Option<W>,
    co: C,
    written: usize,
}

impl<W, C> Encoder<W, C> {
    /// Create a new `Encoder` wrapping an `AsyncWrite` and consuming an `AsyncEncode`.
    pub fn new(writer: W, co: C) -> Encoder<W, C> {
        Encoder {
            writer: Some(writer),
            co,
            written: 0,
        }
    }
}

impl<W, C> Encoder<W, C>
    where W: AsyncWrite,
          C: AsyncEncodeLen<W>
{
    /// Return the exact number of bytes this will still write.
    pub fn remaining_bytes(&self) -> usize {
        self.co.remaining_bytes()
    }
}

impl<W, C> Future for Encoder<W, C>
    where W: AsyncWrite,
          C: AsyncEncode<W>
{
    type Item = (W, usize);
    type Error = (W, FutIoErr);

    fn poll(&mut self, cx: &mut Context) -> Poll<Self::Item, Self::Error> {
        let mut writer = self.writer
            .take()
            .expect("Polled future after completion");
        match self.co.poll_encode(cx, &mut writer) {
            Ok(Ready(0)) => Ok(Ready((writer, self.written))),
            Ok(Ready(written)) => {
                self.written += written;
                self.writer = Some(writer);
                self.poll(cx)
            }
            Ok(Pending) => {
                self.writer = Some(writer);
                Ok(Pending)
            }
            Err(err) => Err((writer, err)),
        }
    }
}

/// Decode a value from an `AsyncRead`, using an `AsyncDecode`.
pub fn decode<R, D>(reader: R, dec: D) -> Decoder<R, D> {
    Decoder::new(reader, dec)
}

/// Future for fully decoding an `AsyncDecode` from an `AsyncRead`.
pub struct Decoder<R, D> {
    reader: Option<R>,
    dec: D,
    read: usize,
}

impl<R, D> Decoder<R, D> {
    /// Create a new `Decoder` wrapping an `AsyncRead` and consuming an `AsyncDecode`.
    pub fn new(reader: R, dec: D) -> Decoder<R, D> {
        Decoder {
            reader: Some(reader),
            dec,
            read: 0,
        }
    }
}

impl<R, D> Future for Decoder<R, D>
    where R: AsyncRead,
          D: AsyncDecode<R>
{
    type Item = (R, D::Item, usize);
    type Error = (R, DecodeError<D::Error>);

    fn poll(&mut self, cx: &mut Context) -> Poll<Self::Item, Self::Error> {
        let mut reader = self.reader
            .take()
            .expect("Polled future after completion");
        match self.dec.poll_decode(cx, &mut reader) {
            Ok(Ready((Some(decoded), read))) => Ok(Ready((reader, decoded, self.read + read))),
            Ok(Ready((None, read))) => {
                self.read += read;
                self.reader = Some(reader);
                self.poll(cx)
            }
            Ok(Pending) => {
                self.reader = Some(reader);
                Ok(Pending)
            }
            Err(err) => Err((reader, err)),
        }
    }
}