Initial Dosh implementation

src/pty.rs

@@ -0,0 +1,84 @@
+use anyhow::{Context, Result};
+use portable_pty::{CommandBuilder, MasterPty, NativePtySystem, PtySize, PtySystem};
+use std::io::{Read, Write};
+use std::sync::{Arc, Mutex};
+use std::thread;
+use tokio::sync::mpsc;
+
+pub struct PtyHandle {
+    writer: Arc<Mutex<Box<dyn Write + Send>>>,
+    _master: Box<dyn MasterPty + Send>,
+}
+
+impl PtyHandle {
+    pub fn write_all(&self, bytes: &[u8]) -> Result<()> {
+        let mut writer = self.writer.lock().expect("pty writer poisoned");
+        writer.write_all(bytes)?;
+        writer.flush()?;
+        Ok(())
+    }
+
+    pub fn resize(&self, cols: u16, rows: u16) -> Result<()> {
+        self._master.resize(PtySize {
+            rows,
+            cols,
+            pixel_width: 0,
+            pixel_height: 0,
+        })?;
+        Ok(())
+    }
+}
+
+#[derive(Debug)]
+pub struct PtyOutput {
+    pub session: String,
+    pub bytes: Vec<u8>,
+}
+
+pub fn spawn_pty_session(
+    session: String,
+    shell: &str,
+    cols: u16,
+    rows: u16,
+    tx: mpsc::UnboundedSender<PtyOutput>,
+) -> Result<PtyHandle> {
+    let pty_system = NativePtySystem::default();
+    let pair = pty_system
+        .openpty(PtySize {
+            rows,
+            cols,
+            pixel_width: 0,
+            pixel_height: 0,
+        })
+        .context("open pty")?;
+    let cmd = CommandBuilder::new(shell);
+    let _child = pair.slave.spawn_command(cmd).context("spawn shell")?;
+    drop(pair.slave);
+
+    let writer = pair.master.take_writer().context("take pty writer")?;
+    let mut reader = pair.master.try_clone_reader().context("clone pty reader")?;
+    let reader_session = session.clone();
+    thread::Builder::new()
+        .name(format!("dosh-pty-{session}"))
+        .spawn(move || {
+            let mut buf = [0u8; 8192];
+            loop {
+                match reader.read(&mut buf) {
+                    Ok(0) => break,
+                    Ok(n) => {
+                        let _ = tx.send(PtyOutput {
+                            session: reader_session.clone(),
+                            bytes: buf[..n].to_vec(),
+                        });
+                    }
+                    Err(_) => break,
+                }
+            }
+        })
+        .context("spawn pty reader")?;
+
+    Ok(PtyHandle {
+        writer: Arc::new(Mutex::new(writer)),
+        _master: pair.master,
+    })
+}