Split alacritty into a separate crates

The crate containing the entry point is called alacritty, and the crate
containing everything else is called alacritty_terminal.

1 files changed, 436 insertions, 0 deletions

diff --git a/alacritty_terminal/src/event_loop.rs b/alacritty_terminal/src/event_loop.rs
new file mode 100644
index 00000000..4941b479
--- /dev/null
+++ b/alacritty_terminal/src/event_loop.rs
@@ -0,0 +1,436 @@
+//! 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 mio::{self, Events, PollOpt, Ready};
+use mio_extras::channel::{self, Receiver, Sender};
+
+#[cfg(not(windows))]
+use mio::unix::UnixReady;
+
+use crate::ansi;
+use crate::display;
+use crate::event;
+use crate::sync::FairMutex;
+use crate::term::Term;
+use crate::tty;
+use crate::util::thread;
+
+/// 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<T: tty::EventedPty> {
+    poll: mio::Poll,
+    pty: T,
+    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()
+    }
+}
+
+impl<T> EventLoop<T>
+where
+    T: tty::EventedPty + Send + 'static,
+{
+    /// Create a new event loop
+    pub fn new(
+        terminal: Arc<FairMutex<Term>>,
+        display: display::Notifier,
+        pty: T,
+        ref_test: bool,
+    ) -> EventLoop<T> {
+        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, token: mio::Token, state: &mut State) -> bool {
+        if self.drain_recv_channel(state).is_shutdown() {
+            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,
+    {
+        const MAX_READ: usize = 0x1_0000;
+        let mut processed = 0;
+        let mut terminal = None;
+
+        // Flag to keep track if wakeup has already been sent
+        let mut send_wakeup = false;
+
+        loop {
+            match self.pty.reader().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
+                    });
+
+                    // Get reference to terminal. Lock is acquired on initial
+                    // iteration and held until there's no bytes left to parse
+                    // or we've reached MAX_READ.
+                    let terminal = if terminal.is_none() {
+                        terminal = Some(self.terminal.lock());
+                        let terminal = terminal.as_mut().unwrap();
+                        send_wakeup = !terminal.dirty;
+                        terminal
+                    } else {
+                        terminal.as_mut().unwrap()
+                    };
+
+                    // Run the parser
+                    for byte in &buf[..got] {
+                        state.parser.advance(&mut **terminal, *byte, &mut self.pty.writer());
+                    }
+
+                    // Exit if we've processed enough bytes
+                    if processed > MAX_READ {
+                        break;
+                    }
+                },
+                Err(err) => match err.kind() {
+                    ErrorKind::Interrupted | ErrorKind::WouldBlock => {
+                        break;
+                    },
+                    _ => return Err(err),
+                },
+            }
+        }
+
+        // Only request a draw if one hasn't already been requested.
+        if let Some(mut terminal) = terminal {
+            if send_wakeup {
+                self.display.notify();
+                terminal.dirty = true;
+            }
+        }
+
+        Ok(())
+    }
+
+    #[inline]
+    fn pty_write(&mut self, state: &mut State) -> io::Result<()> {
+        state.ensure_next();
+
+        'write_many: while let Some(mut current) = state.take_current() {
+            'write_one: loop {
+                match self.pty.writer().write(current.remaining_bytes()) {
+                    Ok(0) => {
+                        state.set_current(Some(current));
+                        break 'write_many;
+                    },
+                    Ok(n) => {
+                        current.advance(n);
+                        if current.finished() {
+                            state.goto_next();
+                            break 'write_one;
+                        }
+                    },
+                    Err(err) => {
+                        state.set_current(Some(current));
+                        match err.kind() {
+                            ErrorKind::Interrupted | ErrorKind::WouldBlock => break 'write_many,
+                            _ => return Err(err),
+                        }
+                    },
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    pub fn spawn(mut self, state: Option<State>) -> thread::JoinHandle<(Self, State)> {
+        thread::spawn_named("pty reader", move || {
+            let mut state = state.unwrap_or_else(Default::default);
+            let mut buf = [0u8; 0x1000];
+
+            let mut tokens = (0..).map(Into::into);
+
+            let poll_opts = PollOpt::edge() | PollOpt::oneshot();
+
+            let channel_token = tokens.next().unwrap();
+            self.poll.register(&self.rx, channel_token, Ready::readable(), poll_opts).unwrap();
+
+            // Register TTY through EventedRW interface
+            self.pty.register(&self.poll, &mut tokens, Ready::readable(), poll_opts).unwrap();
+
+            let mut events = Events::with_capacity(1024);
+
+            let mut pipe = if self.ref_test {
+                Some(File::create("./alacritty.recording").expect("create alacritty recording"))
+            } else {
+                None
+            };
+
+            'event_loop: loop {
+                if let Err(err) = self.poll.poll(&mut events, None) {
+                    match err.kind() {
+                        ErrorKind::Interrupted => continue,
+                        _ => panic!("EventLoop polling error: {:?}", err),
+                    }
+                }
+
+                for event in events.iter() {
+                    match event.token() {
+                        token if token == channel_token => {
+                            if !self.channel_event(channel_token, &mut state) {
+                                break 'event_loop;
+                            }
+                        },
+
+                        #[cfg(unix)]
+                        token if token == self.pty.child_event_token() => {
+                            if let Some(tty::ChildEvent::Exited) = self.pty.next_child_event() {
+                                self.terminal.lock().exit();
+                                self.display.notify();
+                                break 'event_loop;
+                            }
+                        },
+
+                        token
+                            if token == self.pty.read_token()
+                                || token == self.pty.write_token() =>
+                        {
+                            #[cfg(unix)]
+                            {
+                                if UnixReady::from(event.readiness()).is_hup() {
+                                    // don't try to do I/O on a dead PTY
+                                    continue;
+                                }
+                            }
+
+                            if event.readiness().is_readable() {
+                                if let Err(e) = self.pty_read(&mut state, &mut buf, pipe.as_mut()) {
+                                    #[cfg(target_os = "linux")]
+                                    {
+                                        // On Linux, a `read` on the master side of a PTY can fail
+                                        // with `EIO` if the client side hangs up.  In that case,
+                                        // just loop back round for the inevitable `Exited` event.
+                                        // This sucks, but checking the process is either racy or
+                                        // blocking.
+                                        if e.kind() == ErrorKind::Other {
+                                            continue;
+                                        }
+                                    }
+
+                                    error!("Error reading from PTY in event loop: {}", e);
+                                    break 'event_loop;
+                                }
+                            }
+
+                            if event.readiness().is_writable() {
+                                if let Err(e) = self.pty_write(&mut state) {
+                                    error!("Error writing to PTY in event loop: {}", e);
+                                    break 'event_loop;
+                                }
+                            }
+                        }
+                        _ => (),
+                    }
+                }
+
+                // Register write interest if necessary
+                let mut interest = Ready::readable();
+                if state.needs_write() {
+                    interest.insert(Ready::writable());
+                }
+                // Reregister with new interest
+                self.pty.reregister(&self.poll, interest, poll_opts).unwrap();
+            }
+
+            // The evented instances are not dropped here so deregister them explicitly
+            // TODO: Is this still necessary?
+            let _ = self.poll.deregister(&self.rx);
+            let _ = self.pty.deregister(&self.poll);
+
+            (self, state)
+        })
+    }
+}