Add cargo feature for WinPTY

4 files changed, 230 insertions, 163 deletions

diff --git a/alacritty_terminal/src/tty/windows/automatic_backend.rs b/alacritty_terminal/src/tty/windows/automatic_backend.rs
new file mode 100644
index 00000000..74a546dd
--- /dev/null
+++ b/alacritty_terminal/src/tty/windows/automatic_backend.rs
@@ -0,0 +1,189 @@
+/// Types to determine the appropriate PTY backend at runtime.
+///
+/// Unless the winpty feature is disabled, the PTY backend will automatically fall back to
+/// WinPTY when the newer ConPTY API is not supported, as long as the user hasn't explicitly
+/// opted into the WinPTY config option.
+use std::io::{self, Read, Write};
+
+use log::info;
+use mio::{Evented, Poll, PollOpt, Ready, Token};
+use mio_anonymous_pipes::{EventedAnonRead, EventedAnonWrite};
+use mio_named_pipes::NamedPipe;
+
+use crate::config::Config;
+use crate::event::OnResize;
+use crate::term::SizeInfo;
+
+use super::{conpty, winpty, Pty};
+
+pub fn new<C>(config: &Config<C>, size: &SizeInfo, window_id: Option<usize>) -> Pty {
+    if let Some(pty) = conpty::new(config, size, window_id) {
+        info!("Using ConPTY backend");
+        pty
+    } else {
+        info!("Using WinPTY backend");
+        winpty::new(config, size, window_id)
+    }
+}
+
+pub enum PtyBackend {
+    Winpty(winpty::Agent),
+    Conpty(conpty::Conpty),
+}
+
+impl OnResize for PtyBackend {
+    fn on_resize(&mut self, size: &SizeInfo) {
+        match self {
+            PtyBackend::Winpty(w) => w.on_resize(size),
+            PtyBackend::Conpty(c) => c.on_resize(size),
+        }
+    }
+}
+
+// TODO: The ConPTY API currently must use synchronous pipes as the input
+// and output handles. This has led to the need to support two different
+// types of pipe.
+//
+// When https://github.com/Microsoft/console/issues/262 lands then the
+// Anonymous variant of this enum can be removed from the codebase and
+// everything can just use NamedPipe.
+pub enum EventedReadablePipe {
+    Anonymous(EventedAnonRead),
+    Named(NamedPipe),
+}
+
+pub enum EventedWritablePipe {
+    Anonymous(EventedAnonWrite),
+    Named(NamedPipe),
+}
+
+impl Evented for EventedReadablePipe {
+    fn register(
+        &self,
+        poll: &Poll,
+        token: Token,
+        interest: Ready,
+        opts: PollOpt,
+    ) -> io::Result<()> {
+        match self {
+            EventedReadablePipe::Anonymous(p) => p.register(poll, token, interest, opts),
+            EventedReadablePipe::Named(p) => p.register(poll, token, interest, opts),
+        }
+    }
+
+    fn reregister(
+        &self,
+        poll: &Poll,
+        token: Token,
+        interest: Ready,
+        opts: PollOpt,
+    ) -> io::Result<()> {
+        match self {
+            EventedReadablePipe::Anonymous(p) => p.reregister(poll, token, interest, opts),
+            EventedReadablePipe::Named(p) => p.reregister(poll, token, interest, opts),
+        }
+    }
+
+    fn deregister(&self, poll: &Poll) -> io::Result<()> {
+        match self {
+            EventedReadablePipe::Anonymous(p) => p.deregister(poll),
+            EventedReadablePipe::Named(p) => p.deregister(poll),
+        }
+    }
+}
+
+impl Read for EventedReadablePipe {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        match self {
+            EventedReadablePipe::Anonymous(p) => p.read(buf),
+            EventedReadablePipe::Named(p) => p.read(buf),
+        }
+    }
+}
+
+impl Evented for EventedWritablePipe {
+    fn register(
+        &self,
+        poll: &Poll,
+        token: Token,
+        interest: Ready,
+        opts: PollOpt,
+    ) -> io::Result<()> {
+        match self {
+            EventedWritablePipe::Anonymous(p) => p.register(poll, token, interest, opts),
+            EventedWritablePipe::Named(p) => p.register(poll, token, interest, opts),
+        }
+    }
+
+    fn reregister(
+        &self,
+        poll: &Poll,
+        token: Token,
+        interest: Ready,
+        opts: PollOpt,
+    ) -> io::Result<()> {
+        match self {
+            EventedWritablePipe::Anonymous(p) => p.reregister(poll, token, interest, opts),
+            EventedWritablePipe::Named(p) => p.reregister(poll, token, interest, opts),
+        }
+    }
+
+    fn deregister(&self, poll: &Poll) -> io::Result<()> {
+        match self {
+            EventedWritablePipe::Anonymous(p) => p.deregister(poll),
+            EventedWritablePipe::Named(p) => p.deregister(poll),
+        }
+    }
+}
+
+impl Write for EventedWritablePipe {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match self {
+            EventedWritablePipe::Anonymous(p) => p.write(buf),
+            EventedWritablePipe::Named(p) => p.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        match self {
+            EventedWritablePipe::Anonymous(p) => p.flush(),
+            EventedWritablePipe::Named(p) => p.flush(),
+        }
+    }
+}
+
+impl From<winpty::Agent> for PtyBackend {
+    fn from(inner: winpty::Agent) -> Self {
+        PtyBackend::Winpty(inner)
+    }
+}
+
+impl From<conpty::Conpty> for PtyBackend {
+    fn from(inner: conpty::Conpty) -> Self {
+        PtyBackend::Conpty(inner)
+    }
+}
+
+impl From<EventedAnonRead> for EventedReadablePipe {
+    fn from(inner: EventedAnonRead) -> Self {
+        EventedReadablePipe::Anonymous(inner)
+    }
+}
+
+impl From<NamedPipe> for EventedReadablePipe {
+    fn from(inner: NamedPipe) -> Self {
+        EventedReadablePipe::Named(inner)
+    }
+}
+
+impl From<EventedAnonWrite> for EventedWritablePipe {
+    fn from(inner: EventedAnonWrite) -> Self {
+        EventedWritablePipe::Anonymous(inner)
+    }
+}
+
+impl From<NamedPipe> for EventedWritablePipe {
+    fn from(inner: NamedPipe) -> Self {
+        EventedWritablePipe::Named(inner)
+    }
+}
diff --git a/alacritty_terminal/src/tty/windows/conpty.rs b/alacritty_terminal/src/tty/windows/conpty.rs
index 2056f3d6..561df71d 100644
--- a/alacritty_terminal/src/tty/windows/conpty.rs
+++ b/alacritty_terminal/src/tty/windows/conpty.rs
@@ -231,15 +231,7 @@ pub fn new<C>(config: &Config<C>, size: &SizeInfo, _window_id: Option<usize>) ->
     let child_watcher = ChildExitWatcher::new(proc_info.hProcess).unwrap();
     let conpty = Conpty { handle: pty_handle, api };
 
-    Some(Pty {
-        backend: super::PtyBackend::Conpty(conpty),
-        conout: super::EventedReadablePipe::Anonymous(conout),
-        conin: super::EventedWritablePipe::Anonymous(conin),
-        read_token: 0.into(),
-        write_token: 0.into(),
-        child_event_token: 0.into(),
-        child_watcher,
-    })
+    Some(Pty::new(conpty, conout, conin, child_watcher))
 }
 
 // Panic with the last os error as message.
diff --git a/alacritty_terminal/src/tty/windows/mod.rs b/alacritty_terminal/src/tty/windows/mod.rs
index 8e5b4668..47b03d90 100644
--- a/alacritty_terminal/src/tty/windows/mod.rs
+++ b/alacritty_terminal/src/tty/windows/mod.rs
@@ -13,181 +13,78 @@
 // limitations under the License.
 
 use std::ffi::OsStr;
-use std::io::{self, Read, Write};
+use std::io;
 use std::iter::once;
 use std::os::windows::ffi::OsStrExt;
-use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::TryRecvError;
 
-use mio::{self, Evented, Poll, PollOpt, Ready, Token};
-use mio_anonymous_pipes::{EventedAnonRead, EventedAnonWrite};
-use mio_named_pipes::NamedPipe;
-
-use log::info;
-
 use crate::config::{Config, Shell};
 use crate::event::OnResize;
 use crate::term::SizeInfo;
 use crate::tty::windows::child::ChildExitWatcher;
 use crate::tty::{ChildEvent, EventedPty, EventedReadWrite};
 
+#[cfg(feature = "winpty")]
+mod automatic_backend;
 mod child;
 mod conpty;
+#[cfg(feature = "winpty")]
 mod winpty;
 
-static IS_CONPTY: AtomicBool = AtomicBool::new(false);
-
-pub fn is_conpty() -> bool {
-    IS_CONPTY.load(Ordering::Relaxed)
-}
+#[cfg(not(feature = "winpty"))]
+use conpty::Conpty as Backend;
+#[cfg(not(feature = "winpty"))]
+use mio_anonymous_pipes::{EventedAnonRead as ReadPipe, EventedAnonWrite as WritePipe};
 
-enum PtyBackend {
-    Winpty(winpty::Agent),
-    Conpty(conpty::Conpty),
-}
+#[cfg(feature = "winpty")]
+use automatic_backend::{
+    EventedReadablePipe as ReadPipe, EventedWritablePipe as WritePipe, PtyBackend as Backend,
+};
 
 pub struct Pty {
     // XXX: Backend is required to be the first field, to ensure correct drop order. Dropping
-    // `conout` before `backend` will cause a deadlock.
-    backend: PtyBackend,
-    // TODO: It's on the roadmap for the Conpty API to support Overlapped I/O.
-    // See https://github.com/Microsoft/console/issues/262.
-    // When support for that lands then it should be possible to use
-    // NamedPipe for the conout and conin handles.
-    conout: EventedReadablePipe,
-    conin: EventedWritablePipe,
+    // `conout` before `backend` will cause a deadlock (with Conpty).
+    backend: Backend,
+    conout: ReadPipe,
+    conin: WritePipe,
     read_token: mio::Token,
     write_token: mio::Token,
     child_event_token: mio::Token,
     child_watcher: ChildExitWatcher,
 }
 
+#[cfg(not(feature = "winpty"))]
 pub fn new<C>(config: &Config<C>, size: &SizeInfo, window_id: Option<usize>) -> Pty {
-    if let Some(pty) = conpty::new(config, size, window_id) {
-        info!("Using ConPTY backend");
-        IS_CONPTY.store(true, Ordering::Relaxed);
-        pty
-    } else {
-        info!("Using WinPTY backend");
-        winpty::new(config, size, window_id)
-    }
-}
-
-// TODO: The ConPTY API currently must use synchronous pipes as the input
-// and output handles. This has led to the need to support two different
-// types of pipe.
-//
-// When https://github.com/Microsoft/console/issues/262 lands then the
-// Anonymous variant of this enum can be removed from the codebase and
-// everything can just use NamedPipe.
-pub enum EventedReadablePipe {
-    Anonymous(EventedAnonRead),
-    Named(NamedPipe),
-}
-
-pub enum EventedWritablePipe {
-    Anonymous(EventedAnonWrite),
-    Named(NamedPipe),
-}
-
-impl Evented for EventedReadablePipe {
-    fn register(
-        &self,
-        poll: &Poll,
-        token: Token,
-        interest: Ready,
-        opts: PollOpt,
-    ) -> io::Result<()> {
-        match self {
-            EventedReadablePipe::Anonymous(p) => p.register(poll, token, interest, opts),
-            EventedReadablePipe::Named(p) => p.register(poll, token, interest, opts),
-        }
-    }
-
-    fn reregister(
-        &self,
-        poll: &Poll,
-        token: Token,
-        interest: Ready,
-        opts: PollOpt,
-    ) -> io::Result<()> {
-        match self {
-            EventedReadablePipe::Anonymous(p) => p.reregister(poll, token, interest, opts),
-            EventedReadablePipe::Named(p) => p.reregister(poll, token, interest, opts),
-        }
-    }
-
-    fn deregister(&self, poll: &Poll) -> io::Result<()> {
-        match self {
-            EventedReadablePipe::Anonymous(p) => p.deregister(poll),
-            EventedReadablePipe::Named(p) => p.deregister(poll),
-        }
-    }
-}
-
-impl Read for EventedReadablePipe {
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        match self {
-            EventedReadablePipe::Anonymous(p) => p.read(buf),
-            EventedReadablePipe::Named(p) => p.read(buf),
-        }
-    }
+    conpty::new(config, size, window_id).expect("Failed to create ConPTY backend")
 }
 
-impl Evented for EventedWritablePipe {
-    fn register(
-        &self,
-        poll: &Poll,
-        token: Token,
-        interest: Ready,
-        opts: PollOpt,
-    ) -> io::Result<()> {
-        match self {
-            EventedWritablePipe::Anonymous(p) => p.register(poll, token, interest, opts),
-            EventedWritablePipe::Named(p) => p.register(poll, token, interest, opts),
-        }
-    }
-
-    fn reregister(
-        &self,
-        poll: &Poll,
-        token: Token,
-        interest: Ready,
-        opts: PollOpt,
-    ) -> io::Result<()> {
-        match self {
-            EventedWritablePipe::Anonymous(p) => p.reregister(poll, token, interest, opts),
-            EventedWritablePipe::Named(p) => p.reregister(poll, token, interest, opts),
-        }
-    }
-
-    fn deregister(&self, poll: &Poll) -> io::Result<()> {
-        match self {
-            EventedWritablePipe::Anonymous(p) => p.deregister(poll),
-            EventedWritablePipe::Named(p) => p.deregister(poll),
-        }
-    }
+#[cfg(feature = "winpty")]
+pub fn new<C>(config: &Config<C>, size: &SizeInfo, window_id: Option<usize>) -> Pty {
+    automatic_backend::new(config, size, window_id)
 }
 
-impl Write for EventedWritablePipe {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        match self {
-            EventedWritablePipe::Anonymous(p) => p.write(buf),
-            EventedWritablePipe::Named(p) => p.write(buf),
-        }
-    }
-
-    fn flush(&mut self) -> io::Result<()> {
-        match self {
-            EventedWritablePipe::Anonymous(p) => p.flush(),
-            EventedWritablePipe::Named(p) => p.flush(),
+impl Pty {
+    fn new(
+        backend: impl Into<Backend>,
+        conout: impl Into<ReadPipe>,
+        conin: impl Into<WritePipe>,
+        child_watcher: ChildExitWatcher,
+    ) -> Self {
+        Self {
+            backend: backend.into(),
+            conout: conout.into(),
+            conin: conin.into(),
+            read_token: 0.into(),
+            write_token: 0.into(),
+            child_event_token: 0.into(),
+            child_watcher,
         }
     }
 }
 
 impl EventedReadWrite for Pty {
-    type Reader = EventedReadablePipe;
-    type Writer = EventedWritablePipe;
+    type Reader = ReadPipe;
+    type Writer = WritePipe;
 
     #[inline]
     fn register(
@@ -295,10 +192,7 @@ impl EventedPty for Pty {
 
 impl OnResize for Pty {
     fn on_resize(&mut self, size: &SizeInfo) {
-        match &mut self.backend {
-            PtyBackend::Winpty(w) => w.on_resize(size),
-            PtyBackend::Conpty(c) => c.on_resize(size),
-        }
+        self.backend.on_resize(size)
     }
 }
 
diff --git a/alacritty_terminal/src/tty/windows/winpty.rs b/alacritty_terminal/src/tty/windows/winpty.rs
index d466955d..acfa6748 100644
--- a/alacritty_terminal/src/tty/windows/winpty.rs
+++ b/alacritty_terminal/src/tty/windows/winpty.rs
@@ -70,15 +70,7 @@ pub fn new<C>(config: &Config<C>, size: &SizeInfo, _window_id: Option<usize>) ->
 
     let child_watcher = ChildExitWatcher::new(agent.raw_handle()).unwrap();
 
-    Pty {
-        backend: super::PtyBackend::Winpty(agent),
-        conout: super::EventedReadablePipe::Named(conout_pipe),
-        conin: super::EventedWritablePipe::Named(conin_pipe),
-        read_token: 0.into(),
-        write_token: 0.into(),
-        child_event_token: 0.into(),
-        child_watcher,
-    }
+    Pty::new(agent, conout_pipe, conin_pipe, child_watcher)
 }
 
 impl OnResize for Agent {