try to replicate the original more

.gitignore

@@ -1,4 +1,4 @@
 /target
-/output.cast
+output.cast
 .direnv
 /logs

src/asciicast.rs

@@ -8,17 +8,17 @@ use serde::ser::{Serialize, SerializeSeq, Serializer};
 
 #[derive(Serialize)]
 pub struct Header {
-  version: u32,
-  width: u32,
-  height: u32,
+  pub version: u32,
+  pub width: u32,
+  pub height: u32,
 
-  timestamp: Option<u32>,
-  duration: Option<f64>,
-  idle_time_limit: Option<f64>,
-  command: Option<String>,
-  title: Option<String>,
-  env: Option<HashMap<String, String>>,
-  theme: Option<Theme>,
+  pub timestamp: Option<u32>,
+  pub duration: Option<f64>,
+  pub idle_time_limit: Option<f64>,
+  pub command: Option<String>,
+  pub title: Option<String>,
+  pub env: Option<HashMap<String, String>>,
+  pub theme: Option<Theme>,
 }
 
 #[derive(Serialize)]

src/lib.rs

@@ -1,4 +1,6 @@
 #[macro_use]
+extern crate anyhow;
+#[macro_use]
 extern crate serde_derive;
 #[macro_use]
 extern crate tracing;

src/main.rs

@@ -1,12 +1,13 @@
 #[macro_use]
 extern crate tracing;
 
-use std::fs::File;
+use std::process::Command;
+use std::thread;
+use std::{fs::File, io::Write};
 
 use anyhow::Result;
 use clap::{ArgAction, Parser};
-use liveterm::recorder::Terminal;
-use tokio::process::Command;
+use liveterm::{asciicast::Header, recorder::Terminal};
 use tracing::Level;
 
 #[derive(Parser)]
@@ -26,12 +27,53 @@ enum Subcommand {
 }
 
 fn record() -> Result<()> {
-  let _file = File::create("output.cast")?;
+  let mut file = File::create("output.cast")?;
 
-  let mut command = Command::new("/usr/bin/env");
-  command.arg("bash");
+  let mut command = Command::new("zsh");
+  // command.arg("bash");
+  command.env("TERM", "xterm-256color");
+
+  // Write header
+  // TODO: Clean this up
+  let header = {
+    let command_str = format!("{:?}", command);
+    let env = command
+      .get_envs()
+      .into_iter()
+      .filter_map(|(a, b)| b.map(|b| (a, b)))
+      .map(|(a, b)| {
+        (
+          a.to_string_lossy().to_string(),
+          b.to_string_lossy().to_string(),
+        )
+      })
+      .collect();
+    Header {
+      version: 2,
+      width: 30,
+      height: 30,
+
+      timestamp: None,
+      duration: None,
+      idle_time_limit: None,
+      command: Some(command_str),
+      title: None,
+      env: Some(env),
+      theme: None,
+    }
+  };
+
+  serde_json::to_writer(&file, &header)?;
+  file.write(b"\n")?;
 
   let (pty, rx) = Terminal::setup(command)?;
+  thread::spawn(move || {
+    for event in rx.into_iter() {
+      serde_json::to_writer(&file, &event);
+      file.write(b"\n");
+    }
+  });
+
   pty.wait_until_complete()?;
 
   Ok(())

src/recorder.rs

@@ -1,40 +1,66 @@
 //! Setting up a recorder
 
-use std::os::unix::prelude::RawFd;
+use std::env;
+use std::ffi::CString;
+use std::os::unix::prelude::{AsRawFd, OsStrExt, RawFd};
+use std::process::{Command, Stdio};
 use std::sync::mpsc::{self, Receiver, Sender};
+use std::time::Instant;
 
-use anyhow::Result;
-use libc::{STDIN_FILENO, STDOUT_FILENO};
+use anyhow::{Context, Result};
+use libc::{O_RDWR, STDERR_FILENO, STDIN_FILENO, STDOUT_FILENO};
+use nix::fcntl::{open, OFlag};
 use nix::pty::{openpty, OpenptyResult};
 use nix::sys::select::{select, FdSet};
-use nix::unistd::{dup, dup2, fsync, read, write};
-use tokio::process::Command;
+use nix::sys::stat::Mode;
+use nix::unistd::{
+  close, dup, dup2, execvp, execvpe, fork, fsync, read, setsid, ttyname, write,
+  ForkResult,
+};
 
-use crate::asciicast::Event;
+use crate::asciicast::{Event, EventKind};
 
 pub struct Terminal {
-  /// The file descriptor that the parent process' original stdout got duplicated to.
-  ///
-  /// This needs to be saved so we can restore it later.
-  parent_stdout_dup: RawFd,
-
-  pty: OpenptyResult,
-
   event_tx: Sender<Event>,
+  command: Command,
 }
 
 impl Terminal {
-  pub fn setup(mut command: Command) -> Result<(Self, Receiver<Event>)> {
-    command.env("TERM", "xterm-256color");
-
+  pub fn setup(command: Command) -> Result<(Self, Receiver<Event>)> {
     // Set up channels
     let (event_tx, event_rx) = mpsc::channel::<Event>();
 
+    let term = Terminal { event_tx, command };
+    Ok((term, event_rx))
+  }
+
+  pub fn wait_until_complete(self) -> Result<()> {
+    self.run()?;
+
+    Ok(())
+  }
+
+  fn run(self) -> Result<()> {
+    // References:
+    // - https://github.com/python/cpython/blob/main/Lib/pty.py
+    // - https://github.com/asciinema/asciinema/blob/develop/asciinema/pty_.py
+    // TODO: Investigate cross-platformness
+    if cfg!(target_os = "windows") {
+      panic!("Not supported on windows.");
+    }
+
+    let mut command = self.command;
+
+    // Merge environment
+    for (key, val) in env::vars() {
+      command.env(key, val);
+    }
+
     // Open a pty
     let pty = openpty(None, None)?;
     let parent_stdout_dup = dup(STDOUT_FILENO)?;
     info!(parent_stdout_dup, "Duplicated parent process' stdout.");
-    dup2(pty.slave, STDOUT_FILENO)?;
+    // dup2(pty.slave, STDOUT_FILENO)?;
     info!(
       redirected_to = pty.slave,
       "Redirected parent process' stdout to new pty."
@@ -43,71 +69,139 @@ impl Terminal {
     eprintln!("Starting child process...");
 
     // Spawn the child
-    let child = command.spawn()?;
-    let _child_pid = child.id();
+    let child_pid = match unsafe { fork() } {
+      Ok(ForkResult::Parent { child }) => {
+        info!(
+          child_pid = child.as_raw(),
+          "Continuing execution in parent process.",
+        );
 
-    let term = Terminal {
-      parent_stdout_dup,
-      pty,
-      event_tx,
+        close(pty.slave)?;
+
+        child
+      }
+
+      Ok(ForkResult::Child) => {
+        setsid()?;
+        close(pty.master)?;
+
+        // Duplicate all stdio descriptors to slave
+        dup2(pty.slave, STDIN_FILENO)?;
+        dup2(pty.slave, STDOUT_FILENO)?;
+        dup2(pty.slave, STDERR_FILENO)?;
+        if pty.slave > STDERR_FILENO {
+          close(pty.slave)?;
+        }
+
+        let tty_path = ttyname(STDOUT_FILENO)?;
+        let tmp_fd = open(&tty_path, OFlag::O_RDWR, Mode::S_IRWXU)?;
+        close(tmp_fd)?;
+
+        exec_command(command)?;
+        unreachable!()
+      }
+
+      Err(err) => bail!("Could not fork: {}", err),
     };
-    Ok((term, event_rx))
-  }
 
-  pub fn wait_until_complete(self) -> Result<()> {
-    self.run()?;
-
-    // Restore stdout
-    fsync(STDOUT_FILENO)?;
-    dup2(self.parent_stdout_dup, STDOUT_FILENO)?;
-
-    Ok(())
-  }
-
-  fn run(&self) -> Result<()> {
+    // Set up fd sets and buffers for reading
     let mut read_fd_set = FdSet::new();
     let mut buf = [0; 1024];
 
+    // Set up recording function
+    let start_time = Instant::now();
+    let record = |now: Instant, output: bool, data: &[u8]| -> Result<()> {
+      let elapsed = (now - start_time).as_secs_f64();
+      let event_kind = (match output {
+        true => EventKind::Output,
+        false => EventKind::Input,
+      })(data.to_vec());
+      let event = Event(elapsed, event_kind);
+      self.event_tx.send(event)?;
+      Ok(())
+    };
+
     info!("Starting read loop...");
     loop {
       // Set up fdsets
       // asciinema does not capture stdin by default
       read_fd_set.clear();
-      read_fd_set.insert(self.pty.master);
+      read_fd_set.insert(pty.master);
       read_fd_set.insert(STDIN_FILENO);
       // TODO: Signal file descriptor
 
-      select(None, &mut read_fd_set, None, None, None)?;
+      select(None, &mut read_fd_set, None, None, None).context("Select")?;
 
       // Master is ready for read, which means child process stdout has data
       // (child process stdout) -> (pty.slave) -> (pty.master)
-      if read_fd_set.contains(self.pty.master) {
-        let bytes_read = read(self.pty.master, &mut buf)?;
+      if read_fd_set.contains(pty.master) {
+        let bytes_read =
+          read(pty.master, &mut buf).context("Read from master")?;
         if bytes_read == 0 {
           info!("Read 0 bytes, exiting the read loop.");
           break;
         }
+        let now = Instant::now();
 
         let data = &buf[..bytes_read];
         debug!(bytes_read, "Read data from master.");
 
         // We should take this and rewrite this to the current stdout
-        write(STDOUT_FILENO, data)?;
-      }
-      // Stdin is ready for read, which means input from the user
-      else if read_fd_set.contains(STDIN_FILENO) {
-        let bytes_read = read(self.pty.master, &mut buf)?;
-        let data = &buf[..bytes_read];
-        debug!(bytes_read, "Read data from master.");
+        write(STDOUT_FILENO, data).context("Write to current STDOUT")?;
 
-        write(self.pty.master, data)?;
+        // Also, record this
+        record(now, true, data).context("Record data")?;
+      }
+
+      // Stdin is ready for read, which means input from the user
+      if read_fd_set.contains(STDIN_FILENO) {
+        let bytes_read =
+          read(STDIN_FILENO, &mut buf).context("Read from current STDIN")?;
+        let data = &buf[..bytes_read];
+        debug!(bytes_read, "Read data from current STDIN.");
+        let now = Instant::now();
+
+        write(pty.master, data).context("Write to master")?;
+
+        // Also, record this
+        record(now, false, data).context("Record data")?;
       }
     }
 
+    // Restore stdout
+    fsync(STDOUT_FILENO)?;
+    dup2(parent_stdout_dup, STDOUT_FILENO)?;
+
     Ok(())
   }
 }
 
+fn exec_command(command: Command) -> Result<()> {
+  let program = CString::new(command.get_program().as_bytes())?;
+  let args = command
+    .get_args()
+    .into_iter()
+    .map(|osstr| CString::new(osstr.as_bytes()).map_err(|e| e.into()))
+    .collect::<Result<Vec<_>>>()?;
+  let env = command
+    .get_envs()
+    .into_iter()
+    .filter_map(|(key, val)| {
+      let val = match val {
+        Some(val) => val,
+        None => return None,
+      };
+
+      let mut key = key.to_os_string();
+      let equals = String::from("=");
+      key.extend([equals.as_ref(), val]);
+      Some(CString::new(key.as_bytes()).map_err(|e| e.into()))
+    })
+    .collect::<Result<Vec<_>>>()?;
+  execvpe(&program, &args, &env)?;
+  unreachable!()
+}
+
 /*
 pub fn record(args: &[&str], writer: impl Writer + Send) -> Result<()> {
   // Setup