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|
//! The main event loop which performs I/O on the pseudoterminal
use std::borrow::Cow;
use std::collections::VecDeque;
use std::io::{self, ErrorKind, Write};
use std::fs::File;
use std::os::unix::io::AsRawFd;
use std::sync::Arc;
use mio::{self, Events, PollOpt, Ready};
#[cfg(unix)]
use mio::unix::UnixReady;
use mio::unix::EventedFd;
use mio_more::channel::{self, Sender, Receiver};
use ansi;
use display;
use event;
use term::Term;
use util::thread;
use sync::FairMutex;
/// Messages that may be sent to the `EventLoop`
#[derive(Debug)]
pub enum Msg {
/// Data that should be written to the pty
Input(Cow<'static, [u8]>),
/// Indicates that the `EventLoop` should shut down, as Alacritty is shutting down
Shutdown
}
/// The main event!.. loop.
///
/// Handles all the pty I/O and runs the pty parser which updates terminal
/// state.
pub struct EventLoop<Io> {
poll: mio::Poll,
pty: Io,
rx: Receiver<Msg>,
tx: Sender<Msg>,
terminal: Arc<FairMutex<Term>>,
display: display::Notifier,
ref_test: bool,
}
/// Helper type which tracks how much of a buffer has been written.
struct Writing {
source: Cow<'static, [u8]>,
written: usize,
}
/// Indicates the result of draining the mio channel
#[derive(Debug)]
enum DrainResult {
/// At least one new item was received
ReceivedItem,
/// Nothing was available to receive
Empty,
/// A shutdown message was received
Shutdown
}
impl DrainResult {
pub fn is_shutdown(&self) -> bool {
match *self {
DrainResult::Shutdown => true,
_ => false
}
}
}
/// All of the mutable state needed to run the event loop
///
/// Contains list of items to write, current write state, etc. Anything that
/// would otherwise be mutated on the `EventLoop` goes here.
pub struct State {
write_list: VecDeque<Cow<'static, [u8]>>,
writing: Option<Writing>,
parser: ansi::Processor,
}
pub struct Notifier(pub Sender<Msg>);
impl event::Notify for Notifier {
fn notify<B>(&mut self, bytes: B)
where B: Into<Cow<'static, [u8]>>
{
let bytes = bytes.into();
// terminal hangs if we send 0 bytes through.
if bytes.len() == 0 {
return
}
if self.0.send(Msg::Input(bytes)).is_err() {
panic!("expected send event loop msg");
}
}
}
impl Default for State {
fn default() -> State {
State {
write_list: VecDeque::new(),
parser: ansi::Processor::new(),
writing: None,
}
}
}
impl State {
#[inline]
fn ensure_next(&mut self) {
if self.writing.is_none() {
self.goto_next();
}
}
#[inline]
fn goto_next(&mut self) {
self.writing = self.write_list
.pop_front()
.map(Writing::new);
}
#[inline]
fn take_current(&mut self) -> Option<Writing> {
self.writing.take()
}
#[inline]
fn needs_write(&self) -> bool {
self.writing.is_some() || !self.write_list.is_empty()
}
#[inline]
fn set_current(&mut self, new: Option<Writing>) {
self.writing = new;
}
}
impl Writing {
#[inline]
fn new(c: Cow<'static, [u8]>) -> Writing {
Writing { source: c, written: 0 }
}
#[inline]
fn advance(&mut self, n: usize) {
self.written += n;
}
#[inline]
fn remaining_bytes(&self) -> &[u8] {
&self.source[self.written..]
}
#[inline]
fn finished(&self) -> bool {
self.written >= self.source.len()
}
}
/// `mio::Token` for the event loop channel
const CHANNEL: mio::Token = mio::Token(0);
/// `mio::Token` for the pty file descriptor
const PTY: mio::Token = mio::Token(1);
impl<Io> EventLoop<Io>
where Io: io::Read + io::Write + Send + AsRawFd + 'static
{
/// Create a new event loop
pub fn new(
terminal: Arc<FairMutex<Term>>,
display: display::Notifier,
pty: Io,
ref_test: bool,
) -> EventLoop<Io> {
let (tx, rx) = channel::channel();
EventLoop {
poll: mio::Poll::new().expect("create mio Poll"),
pty,
tx,
rx,
terminal,
display,
ref_test,
}
}
pub fn channel(&self) -> Sender<Msg> {
self.tx.clone()
}
// Drain the channel
//
// Returns a `DrainResult` indicating the result of receiving from the channel
//
fn drain_recv_channel(&self, state: &mut State) -> DrainResult {
let mut received_item = false;
while let Ok(msg) = self.rx.try_recv() {
received_item = true;
match msg {
Msg::Input(input) => {
state.write_list.push_back(input);
},
Msg::Shutdown => {
return DrainResult::Shutdown;
}
}
}
if received_item {
DrainResult::ReceivedItem
} else {
DrainResult::Empty
}
}
// Returns a `bool` indicating whether or not the event loop should continue running
#[inline]
fn channel_event(&mut self, state: &mut State) -> bool {
if self.drain_recv_channel(state).is_shutdown() {
return false;
}
self.poll.reregister(
&self.rx, CHANNEL,
Ready::readable(),
PollOpt::edge() | PollOpt::oneshot()
).expect("reregister channel");
if state.needs_write() {
self.poll.reregister(
&EventedFd(&self.pty.as_raw_fd()),
PTY,
Ready::readable() | Ready::writable(),
PollOpt::edge() | PollOpt::oneshot()
).expect("reregister fd after channel recv");
}
true
}
#[inline]
fn pty_read<W>(
&mut self,
state: &mut State,
buf: &mut [u8],
mut writer: Option<&mut W>
) -> io::Result<()>
where W: Write
{
const MAX_READ: usize = 0x1_0000;
let mut processed = 0;
let mut terminal = None;
loop {
match self.pty.read(&mut buf[..]) {
Ok(0) => break,
Ok(got) => {
// Record bytes read; used to limit time spent in pty_read.
processed += got;
// Send a copy of bytes read to a subscriber. Used for
// example with ref test recording.
writer = writer.map(|w| {
w.write_all(&buf[..got]).unwrap();
w
});
|