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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::fs::File;
use std::io::{self, ErrorKind, Read, Write};
use std::marker::Send;
use std::sync::Arc;
use std::thread::JoinHandle;
use std::time::Instant;
use log::error;
#[cfg(not(windows))]
use mio::unix::UnixReady;
use mio::{self, Events, PollOpt, Ready};
use mio_extras::channel::{self, Receiver, Sender};
use crate::event::{self, Event, EventListener};
use crate::sync::FairMutex;
use crate::term::{SizeInfo, Term};
use crate::{ansi, thread, tty};
/// Max bytes to read from the PTY before forced terminal synchronization.
const READ_BUFFER_SIZE: usize = 0x10_0000;
/// Max bytes to read from the PTY while the terminal is locked.
const MAX_LOCKED_READ: usize = u16::max_value() as usize;
/// 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,
/// Instruction to resize the PTY.
Resize(SizeInfo),
}
/// The main event!.. loop.
///
/// Handles all the PTY I/O and runs the PTY parser which updates terminal
/// state.
pub struct EventLoop<T: tty::EventedPty, U: EventListener> {
poll: mio::Poll,
pty: T,
rx: Receiver<Msg>,
tx: Sender<Msg>,
terminal: Arc<FairMutex<Term<U>>>,
event_proxy: U,
hold: bool,
ref_test: bool,
}
/// Helper type which tracks how much of a buffer has been written.
struct Writing {
source: Cow<'static, [u8]>,
written: usize,
}
pub struct Notifier(pub Sender<Msg>);
impl event::Notify for Notifier {
fn notify<B>(&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;
}
let _ = self.0.send(Msg::Input(bytes));
}
}
impl event::OnResize for Notifier {
fn on_resize(&mut self, size: &SizeInfo) {
let _ = self.0.send(Msg::Resize(*size));
}
}
/// 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.
#[derive(Default)]
pub struct State {
write_list: VecDeque<Cow<'static, [u8]>>,
writing: Option<Writing>,
parser: ansi::Processor,
}
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()
}
}
impl<T, U> EventLoop<T, U>
where
T: tty::EventedPty + event::OnResize + Send + 'static,
U: EventListener + Send + 'static,
{
/// Create a new event loop.
pub fn new(
terminal: Arc<FairMutex<Term<U>>>,
event_proxy: U,
pty: T,
hold: bool,
ref_test: bool,
) -> EventLoop<T, U> {
let (tx, rx) = channel::channel();
EventLoop {
poll: mio::Poll::new().expect("create mio Poll"),
pty,
tx,
rx,
terminal,
event_proxy,
hold,
ref_test,
}
}
pub fn channel(&self) -> Sender<Msg> {
self.tx.clone()
}
/// Drain the channel.
///
/// Returns `false` when a shutdown message was received.
fn drain_recv_channel(&mut self, state: &mut State) -> bool {
while let Ok(msg) = self.rx.try_recv() {
match msg {
Msg::Input(input) => state.write_list.push_back(input),
Msg::Resize(size) => self.pty.on_resize(&size),
Msg::Shutdown => return false,
}
}
true
}
/// Returns a `bool` indicating whether or not the event loop should continue running.
#[inline]
fn channel_event(&mut self, token: mio::Token, state: &mut State) -> bool {
if !self.drain_recv_channel(state) {
return false;
}
self.poll
.reregister(&self.rx, token, Ready::readable(), PollOpt::edge() | PollOpt::oneshot())
.unwrap();
true
}
#[inline]
fn pty_read<X>(
&mut self,
state: &mut State,
buf: &mut [u8],
mut writer: Option<&mut X>,
) -> io::Result<()>
where
X: Write,
{
let mut unprocessed = 0;
let mut processed = 0;
// Reserve the next terminal lock for PTY reading.
let _terminal_lease = Some(self.terminal.lease());
let mut terminal = None;
loop {
// Read from the PTY.
match self.pty.reader().read(&mut buf[unprocessed..]) {
// This is received on Windows/macOS when no more data is readable from the PTY.
Ok(0) if unprocessed == 0 => break,
Ok(got) => unprocessed += got,
Err(err) => match err.kind() {
ErrorKind::Interrupted | ErrorKind::WouldBlock => {
// Go back to mio if we're caught up on parsing and the PTY would block.
if unprocessed == 0 {
break;
}
},
_
|