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225 lines
6.5 KiB
225 lines
6.5 KiB
use std::collections::VecDeque;
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use std::error;
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use std::fmt;
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use std::io;
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use std::net::ToSocketAddrs;
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use mio;
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use super::packet::{MutPacket, Parser, ReadFromPacket, WriteToPacket};
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/*========*
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* OUTBUF *
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*========*/
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/// A struct used for writing bytes to a TryWrite sink.
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#[derive(Debug)]
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struct OutBuf {
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cursor: usize,
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bytes: Vec<u8>,
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}
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impl From<Vec<u8>> for OutBuf {
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fn from(bytes: Vec<u8>) -> Self {
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OutBuf {
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cursor: 0,
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bytes: bytes,
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}
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}
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}
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impl OutBuf {
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#[inline]
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fn remaining(&self) -> usize {
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self.bytes.len() - self.cursor
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}
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#[inline]
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fn has_remaining(&self) -> bool {
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self.remaining() > 0
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}
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fn try_write_to<T>(&mut self, mut writer: T) -> io::Result<Option<usize>>
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where
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T: mio::deprecated::TryWrite,
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{
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let result = writer.try_write(&self.bytes[self.cursor..]);
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if let Ok(Some(bytes_written)) = result {
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self.cursor += bytes_written;
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}
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result
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}
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}
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/*========*
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* STREAM *
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*========*/
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/// This trait is implemented by packet sinks to which a stream can forward
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/// the packets it reads.
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pub trait SendPacket {
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type Value: ReadFromPacket;
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type Error: error::Error;
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fn send_packet(&mut self, Self::Value) -> Result<(), Self::Error>;
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fn notify_open(&mut self) -> Result<(), Self::Error>;
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}
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/// This enum defines the possible actions the stream wants to take after
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/// processing an event.
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#[derive(Debug, Clone, Copy)]
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pub enum Intent {
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/// The stream is done, the event loop handler can drop it.
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Done,
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/// The stream wants to wait for the next event matching the given
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/// `EventSet`.
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Continue(mio::Ready),
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}
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/// This struct wraps around an mio tcp stream and handles packet reads and
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/// writes.
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#[derive(Debug)]
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pub struct Stream<T: SendPacket> {
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parser: Parser,
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queue: VecDeque<OutBuf>,
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sender: T,
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stream: mio::tcp::TcpStream,
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is_connected: bool,
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}
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impl<T: SendPacket> Stream<T> {
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/// Returns a new stream, asynchronously connected to the given address,
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/// which forwards incoming packets to the given sender.
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/// If an error occurs when connecting, returns an error.
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pub fn new<U>(addr_spec: U, sender: T) -> io::Result<Self>
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where
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U: ToSocketAddrs + fmt::Debug,
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{
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for sock_addr in try!(addr_spec.to_socket_addrs()) {
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if let Ok(stream) = mio::tcp::TcpStream::connect(&sock_addr) {
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return Ok(Stream {
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parser: Parser::new(),
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queue: VecDeque::new(),
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sender: sender,
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stream: stream,
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is_connected: false,
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});
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}
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}
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Err(io::Error::new(
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io::ErrorKind::Other,
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format!("Cannot connect to {:?}", addr_spec),
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))
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}
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/// Returns a reference to the underlying byte stream, to allow it to be
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/// registered with an event loop.
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pub fn evented(&self) -> &mio::tcp::TcpStream {
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&self.stream
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}
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/// The stream is ready to be read from.
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fn on_readable(&mut self) -> Result<(), String> {
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loop {
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let mut packet = match self.parser.try_read(&mut self.stream) {
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Ok(Some(packet)) => packet,
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Ok(None) => break,
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Err(e) => return Err(format!("Error reading stream: {}", e)),
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};
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let value = match packet.read_value() {
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Ok(value) => value,
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Err(e) => return Err(format!("Error parsing packet: {}", e)),
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};
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if let Err(e) = self.sender.send_packet(value) {
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return Err(format!("Error sending parsed packet: {}", e));
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}
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}
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Ok(())
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}
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/// The stream is ready to be written to.
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fn on_writable(&mut self) -> io::Result<()> {
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loop {
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let mut outbuf = match self.queue.pop_front() {
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Some(outbuf) => outbuf,
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None => break,
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};
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let option = try!(outbuf.try_write_to(&mut self.stream));
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match option {
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Some(_) => {
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if outbuf.has_remaining() {
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self.queue.push_front(outbuf)
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}
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// Continue looping
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}
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None => {
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self.queue.push_front(outbuf);
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break;
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}
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}
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}
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Ok(())
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}
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/// The stream is ready to read, write, or both.
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pub fn on_ready(&mut self, event_set: mio::Ready) -> Intent {
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if event_set.is_hup() || event_set.is_error() {
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return Intent::Done;
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}
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if event_set.is_readable() {
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let result = self.on_readable();
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if let Err(e) = result {
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error!("Stream input error: {}", e);
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return Intent::Done;
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}
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}
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if event_set.is_writable() {
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let result = self.on_writable();
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if let Err(e) = result {
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error!("Stream output error: {}", e);
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return Intent::Done;
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}
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}
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// We must have read or written something succesfully if we're here,
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// so the stream must be connected.
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if !self.is_connected {
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// If we weren't already connected, notify the sink.
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if let Err(err) = self.sender.notify_open() {
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error!("Cannot notify client that stream is open: {}", err);
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return Intent::Done;
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}
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// And record the fact that we are now connected.
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self.is_connected = true;
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}
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// We're always interested in reading more.
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let mut event_set = mio::Ready::readable() | mio::Ready::hup() | mio::Ready::error();
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// If there is still stuff to write in the queue, we're interested in
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// the socket becoming writable too.
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if self.queue.len() > 0 {
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event_set = event_set | mio::Ready::writable();
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}
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Intent::Continue(event_set)
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}
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/// The stream has been notified.
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pub fn on_notify<V>(&mut self, payload: &V) -> Intent
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where
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V: WriteToPacket,
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{
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let mut packet = MutPacket::new();
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let result = packet.write_value(payload);
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if let Err(e) = result {
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error!("Error writing payload to packet: {}", e);
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return Intent::Done;
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}
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self.queue.push_back(OutBuf::from(packet.into_bytes()));
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Intent::Continue(mio::Ready::readable() | mio::Ready::writable())
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}
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}
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