Refactor session/pty/tty

Cargo.lock

@@ -87,6 +87,7 @@ name = "asciinema"
 version = "3.0.0-rc.4"
 dependencies = [
  "anyhow",
+ "async-trait",
  "avt",
  "axum",
  "clap",
@@ -104,8 +105,8 @@ dependencies = [
  "serde",
  "serde_json",
  "signal-hook",
+ "signal-hook-tokio",
  "tempfile",
- "termion",
  "tokio",
  "tokio-stream",
  "tokio-tungstenite",
@@ -131,6 +132,17 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "async-trait"
+version = "0.1.88"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e539d3fca749fcee5236ab05e93a52867dd549cc157c8cb7f99595f3cedffdb5"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.4.0"
@@ -248,7 +260,7 @@ version = "0.69.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "271383c67ccabffb7381723dea0672a673f292304fcb45c01cc648c7a8d58088"
 dependencies = [
- "bitflags 2.9.0",
+ "bitflags",
  "cexpr",
  "clang-sys",
  "itertools",
@@ -265,12 +277,6 @@ dependencies = [
  "which 4.4.2",
 ]
 
-[[package]]
-name = "bitflags"
-version = "1.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
-
 [[package]]
 name = "bitflags"
 version = "2.9.0"
@@ -1044,17 +1050,6 @@ dependencies = [
  "windows-targets 0.52.6",
 ]
 
-[[package]]
-name = "libredox"
-version = "0.0.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3af92c55d7d839293953fcd0fda5ecfe93297cfde6ffbdec13b41d99c0ba6607"
-dependencies = [
- "bitflags 2.9.0",
- "libc",
- "redox_syscall",
-]
-
 [[package]]
 name = "linux-raw-sys"
 version = "0.4.15"
@@ -1148,7 +1143,7 @@ version = "0.27.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2eb04e9c688eff1c89d72b407f168cf79bb9e867a9d3323ed6c01519eb9cc053"
 dependencies = [
- "bitflags 2.9.0",
+ "bitflags",
  "cfg-if",
  "libc",
 ]
@@ -1159,7 +1154,7 @@ version = "0.30.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "74523f3a35e05aba87a1d978330aef40f67b0304ac79c1c00b294c9830543db6"
 dependencies = [
- "bitflags 2.9.0",
+ "bitflags",
  "cfg-if",
  "cfg_aliases",
  "libc",
@@ -1175,12 +1170,6 @@ dependencies = [
  "minimal-lexical",
 ]
 
-[[package]]
-name = "numtoa"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8f8bdf33df195859076e54ab11ee78a1b208382d3a26ec40d142ffc1ecc49ef"
-
 [[package]]
 name = "object"
 version = "0.36.7"
@@ -1352,21 +1341,6 @@ dependencies = [
  "getrandom 0.3.2",
 ]
 
-[[package]]
-name = "redox_syscall"
-version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4722d768eff46b75989dd134e5c353f0d6296e5aaa3132e776cbdb56be7731aa"
-dependencies = [
- "bitflags 1.3.2",
-]
-
-[[package]]
-name = "redox_termios"
-version = "0.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "20145670ba436b55d91fc92d25e71160fbfbdd57831631c8d7d36377a476f1cb"
-
 [[package]]
 name = "regex"
 version = "1.11.1"
@@ -1545,7 +1519,7 @@ version = "0.38.44"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fdb5bc1ae2baa591800df16c9ca78619bf65c0488b41b96ccec5d11220d8c154"
 dependencies = [
- "bitflags 2.9.0",
+ "bitflags",
  "errno",
  "libc",
  "linux-raw-sys 0.4.15",
@@ -1558,7 +1532,7 @@ version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c71e83d6afe7ff64890ec6b71d6a69bb8a610ab78ce364b3352876bb4c801266"
 dependencies = [
- "bitflags 2.9.0",
+ "bitflags",
  "errno",
  "libc",
  "linux-raw-sys 0.9.4",
@@ -1634,7 +1608,7 @@ version = "13.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "02a2d683a4ac90aeef5b1013933f6d977bd37d51ff3f4dad829d4931a7e6be86"
 dependencies = [
- "bitflags 2.9.0",
+ "bitflags",
  "cfg-if",
  "clipboard-win",
  "libc",
@@ -1677,7 +1651,7 @@ version = "3.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "271720403f46ca04f7ba6f55d438f8bd878d6b8ca0a1046e8228c4145bcbb316"
 dependencies = [
- "bitflags 2.9.0",
+ "bitflags",
  "core-foundation",
  "core-foundation-sys",
  "libc",
@@ -1803,6 +1777,18 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "signal-hook-tokio"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "213241f76fb1e37e27de3b6aa1b068a2c333233b59cca6634f634b80a27ecf1e"
+dependencies = [
+ "futures-core",
+ "libc",
+ "signal-hook",
+ "tokio",
+]
+
 [[package]]
 name = "slab"
 version = "0.4.9"
@@ -1890,18 +1876,6 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
-[[package]]
-name = "termion"
-version = "3.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "417813675a504dfbbf21bfde32c03e5bf9f2413999962b479023c02848c1c7a5"
-dependencies = [
- "libc",
- "libredox",
- "numtoa",
- "redox_termios",
-]
-
 [[package]]
 name = "thiserror"
 version = "2.0.12"
@@ -1959,15 +1933,16 @@ checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
 
 [[package]]
 name = "tokio"
-version = "1.44.2"
+version = "1.45.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e6b88822cbe49de4185e3a4cbf8321dd487cf5fe0c5c65695fef6346371e9c48"
+checksum = "75ef51a33ef1da925cea3e4eb122833cb377c61439ca401b770f54902b806779"
 dependencies = [
  "backtrace",
  "bytes",
  "libc",
  "mio",
  "pin-project-lite",
+ "signal-hook-registry",
  "socket2",
  "tokio-macros",
  "windows-sys 0.52.0",
@@ -2092,7 +2067,7 @@ version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "403fa3b783d4b626a8ad51d766ab03cb6d2dbfc46b1c5d4448395e6628dc9697"
 dependencies = [
- "bitflags 2.9.0",
+ "bitflags",
  "bytes",
  "http",
  "http-body",
@@ -2641,7 +2616,7 @@ version = "0.39.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6f42320e61fe2cfd34354ecb597f86f413484a798ba44a8ca1165c58d42da6c1"
 dependencies = [
- "bitflags 2.9.0",
+ "bitflags",
 ]
 
 [[package]]

Cargo.toml

@@ -16,7 +16,6 @@ rust-version = "1.75.0"
 [dependencies]
 anyhow = "1.0.98"
 nix = { version = "0.30", features = ["fs", "term", "process", "signal", "poll"] }
-termion = "3.0.0"
 serde = { version = "1.0.219", features = ["derive"] }
 serde_json = "1.0.140"
 clap = { version = "4.5.37", features = ["derive"] }
@@ -29,7 +28,7 @@ which = "6.0.3"
 tempfile = "3.9.0"
 avt = "0.16.0"
 axum = { version = "0.8.4", default-features = false, features = ["http1", "ws"] }
-tokio = { version = "1.44.2", features = ["rt-multi-thread", "net", "sync", "time"] }
+tokio = { version = "1.45.1", features = ["rt-multi-thread", "net", "sync", "time", "fs", "process"] }
 futures-util = { version = "0.3.31", default-features = false, features = ["sink"] }
 tokio-stream = { version = "0.1.17", default-features = false, features = ["sync", "time"] }
 rust-embed = "8.2.0"
@@ -42,6 +41,8 @@ tokio-tungstenite = { version = "0.26.2", default-features = false, features = [
 rustls = { version = "0.23.26", default-features = false, features = ["aws_lc_rs"] }
 tokio-util = { version = "0.7.10", features = ["rt"] }
 rand = "0.9.1"
+async-trait = "0.1.88"
+signal-hook-tokio = { version = "0.3.1", features = ["futures-v0_3"] }
 
 [build-dependencies]
 clap = { version = "4.5.37", features = ["derive"] }

src/alis.rs

@@ -6,7 +6,6 @@
 
 use std::future;
 
-use anyhow::Result;
 use futures_util::{stream, Stream, StreamExt};
 use tokio_stream::wrappers::errors::BroadcastStreamRecvError;
 

src/cmd/play.rs

@@ -1,37 +1,34 @@
-use anyhow::Result;
+use tokio::runtime::Runtime;
 
 use crate::asciicast;
 use crate::cli;
 use crate::config::{self, Config};
 use crate::player::{self, KeyBindings};
 use crate::status;
-use crate::tty;
 use crate::util;
 
 impl cli::Play {
-    pub fn run(self) -> Result<()> {
+    pub fn run(self) -> anyhow::Result<()> {
         let config = Config::new(None)?;
         let speed = self.speed.or(config.playback.speed).unwrap_or(1.0);
         let idle_time_limit = self.idle_time_limit.or(config.playback.idle_time_limit);
+        let path = util::get_local_path(&self.file)?;
+        let keys = get_key_bindings(&config.playback)?;
+        let runtime = Runtime::new()?;
 
         status::info!("Replaying session from {}", self.file);
 
-        let path = util::get_local_path(&self.file)?;
-        let keys = get_key_bindings(&config.playback)?;
-
         let ended = loop {
             let recording = asciicast::open_from_path(&*path)?;
-            let tty = tty::DevTty::open()?;
 
-            let ended = player::play(
+            let ended = runtime.block_on(player::play(
                 recording,
-                tty,
                 speed,
                 idle_time_limit,
                 self.pause_on_markers,
                 &keys,
                 self.resize,
-            )?;
+            ))?;
 
             if !self.loop_ || !ended {
                 break ended;
@@ -48,7 +45,7 @@ impl cli::Play {
     }
 }
 
-fn get_key_bindings(config: &config::Playback) -> Result<KeyBindings> {
+fn get_key_bindings(config: &config::Playback) -> anyhow::Result<KeyBindings> {
     let mut keys = KeyBindings::default();
 
     if let Some(key) = config.pause_key()? {

src/cmd/session.rs

@@ -1,13 +1,11 @@
 use std::collections::{HashMap, HashSet};
 use std::env;
-use std::fs::{self, File, OpenOptions};
-use std::io::LineWriter;
-use std::net::TcpListener;
 use std::path::{Path, PathBuf};
 use std::process::ExitCode;
 use std::time::{Duration, SystemTime};
 
 use anyhow::{anyhow, bail, Context, Result};
+use tokio::net::TcpListener;
 use tokio::runtime::Runtime;
 use tokio::time;
 use tokio_util::sync::CancellationToken;
@@ -20,15 +18,14 @@ use crate::api;
 use crate::asciicast::{self, Version};
 use crate::cli::{self, Format, RelayTarget};
 use crate::config::{self, Config};
-use crate::encoder::{AsciicastV2Encoder, AsciicastV3Encoder, RawEncoder, TextEncoder};
+use crate::encoder::{AsciicastV2Encoder, AsciicastV3Encoder, Encoder, RawEncoder, TextEncoder};
 use crate::file_writer::FileWriter;
 use crate::forwarder;
 use crate::hash;
 use crate::locale;
-use crate::notifier::{self, Notifier, NullNotifier};
+use crate::notifier::{self, BackgroundNotifier, Notifier, NullNotifier};
-use crate::pty;
 use crate::server;
-use crate::session::{self, KeyBindings, Metadata, Session, TermInfo};
+use crate::session::{self, KeyBindings, Metadata, TermInfo};
 use crate::status;
 use crate::stream::Stream;
 use crate::tty::{DevTty, FixedSizeTty, NullTty, Tty};
@@ -37,15 +34,25 @@ impl cli::Session {
     pub fn run(mut self) -> Result<ExitCode> {
         locale::check_utf8_locale()?;
 
+        let exit_status = Runtime::new()?.block_on(self.do_run())?;
+
+        if !self.return_ || exit_status == 0 {
+            Ok(ExitCode::from(0))
+        } else if exit_status > 0 {
+            Ok(ExitCode::from(exit_status as u8))
+        } else {
+            Ok(ExitCode::from(1))
+        }
+    }
+
+    async fn do_run(&mut self) -> Result<i32> {
         let config = Config::new(self.server_url.clone())?;
-        let runtime = Runtime::new()?;
         let command = self.get_command(&config.recording);
         let keys = get_key_bindings(&config.recording)?;
-        let notifier = notifier::threaded(get_notifier(&config));
+        let notifier = get_notifier(&config);
-        let signal_fd = pty::open_signal_fd()?;
+        let metadata = self.get_session_metadata(&config.recording).await?;
-        let metadata = self.get_session_metadata(&config.recording)?;
+        let file_writer = self.get_file_writer(&metadata, notifier.clone()).await?;
-        let file_writer = self.get_file_writer(&metadata, notifier.clone())?;
+        let listener = self.get_listener().await?;
-        let listener = self.get_listener()?;
         let relay = self.get_relay(&metadata, &config)?;
         let relay_id = relay.as_ref().map(|r| r.id());
         let parent_session_relay_id = get_parent_session_relay_id();
@@ -101,12 +108,12 @@ impl cli::Session {
         let mut outputs: Vec<Box<dyn session::Output>> = Vec::new();
 
         if let Some(writer) = file_writer {
-            let output = writer.start()?;
+            let output = writer.start().await?;
             outputs.push(Box::new(output));
         }
 
         let server = listener.map(|listener| {
-            runtime.spawn(server::serve(
+            tokio::spawn(server::serve(
                 listener,
                 stream.subscriber(),
                 shutdown_token.clone(),
@@ -114,7 +121,7 @@ impl cli::Session {
         });
 
         let forwarder = relay.map(|relay| {
-            runtime.spawn(forwarder::forward(
+            tokio::spawn(forwarder::forward(
                 relay.ws_producer_url,
                 stream.subscriber(),
                 notifier.clone(),
@@ -123,33 +130,29 @@ impl cli::Session {
         });
 
         if server.is_some() || forwarder.is_some() {
-            let output = stream.start(runtime.handle().clone(), &metadata);
+            let output = stream.start(&metadata).await;
             outputs.push(Box::new(output));
         }
 
-        let exit_status = {
+        let command = &build_exec_command(command.as_ref().cloned());
-            let mut tty = self.get_tty(true)?;
+        let extra_env = &build_exec_extra_env(relay_id.as_ref());
 
-            let mut session = Session::new(
+        let exit_status = {
-                outputs,
+            let mut tty = self.get_tty(true).await?;
-                metadata.term.size,
+
+            session::run(
+                command,
+                extra_env,
+                tty.as_mut(),
                 self.rec_input || config.recording.rec_input,
+                outputs,
                 keys,
                 notifier,
-            );
+            )
-
+            .await?
-            pty::exec(
-                &build_exec_command(command.as_ref().cloned()),
-                &build_exec_extra_env(relay_id.as_ref()),
-                metadata.term.size,
-                &mut tty,
-                &mut session,
-                signal_fd,
-            )?
         };
 
-        runtime.block_on(async {
+        status::info!("asciinema session ended");
-            debug!("session shutting down...");
         shutdown_token.cancel();
 
         if let Some(task) = server {
@@ -162,28 +165,17 @@ impl cli::Session {
             let _ = time::timeout(Duration::from_secs(5), task).await;
         }
 
-            debug!("shutdown complete");
+        Ok(exit_status)
-        });
-
-        status::info!("asciinema session ended");
-
-        if !self.return_ || exit_status == 0 {
-            Ok(ExitCode::from(0))
-        } else if exit_status > 0 {
-            Ok(ExitCode::from(exit_status as u8))
-        } else {
-            Ok(ExitCode::from(1))
-        }
     }
 
     fn get_command(&self, config: &config::Recording) -> Option<String> {
         self.command.as_ref().cloned().or(config.command.clone())
     }
 
-    fn get_session_metadata(&self, config: &config::Recording) -> Result<Metadata> {
+    async fn get_session_metadata(&self, config: &config::Recording) -> Result<Metadata> {
         Ok(Metadata {
             time: SystemTime::now(),
-            term: self.get_term_info()?,
+            term: self.get_term_info().await?,
             idle_time_limit: self.idle_time_limit.or(config.idle_time_limit),
             command: self.get_command(config),
             title: self.title.clone(),
@@ -191,18 +183,18 @@ impl cli::Session {
         })
     }
 
-    fn get_term_info(&self) -> Result<TermInfo> {
+    async fn get_term_info(&self) -> Result<TermInfo> {
-        let tty = self.get_tty(false)?;
+        let tty = self.get_tty(false).await?;
 
         Ok(TermInfo {
             type_: env::var("TERM").ok(),
-            version: tty.get_version(),
+            version: tty.get_version().await,
             size: tty.get_size().into(),
-            theme: tty.get_theme(),
+            theme: tty.get_theme().await,
         })
     }
 
-    fn get_file_writer<N: Notifier + 'static>(
+    async fn get_file_writer<N: Notifier + 'static>(
         &self,
         metadata: &Metadata,
         notifier: N,
@@ -213,47 +205,18 @@ impl cli::Session {
 
         let path = Path::new(path);
         let (overwrite, append) = self.get_file_mode(path)?;
-        let file = self.open_output_file(path, overwrite, append)?;
+        let file = self.open_output_file(path, overwrite, append).await?;
         let format = self.get_file_format(path, append)?;
+        let writer = Box::new(file);
         let notifier = Box::new(notifier);
+        let encoder = self.get_encoder(format, path, append)?;
 
-        let file_writer = match format {
+        Ok(Some(FileWriter::new(
-            Format::AsciicastV3 => {
+            writer,
-                let writer = Box::new(LineWriter::new(file));
+            encoder,
-                let encoder = Box::new(AsciicastV3Encoder::new(append));
+            notifier,
-
+            metadata.clone(),
-                FileWriter::new(writer, encoder, notifier, metadata.clone())
+        )))
-            }
-
-            Format::AsciicastV2 => {
-                let time_offset = if append {
-                    asciicast::get_duration(path)?
-                } else {
-                    0
-                };
-
-                let writer = Box::new(LineWriter::new(file));
-                let encoder = Box::new(AsciicastV2Encoder::new(append, time_offset));
-
-                FileWriter::new(writer, encoder, notifier, metadata.clone())
-            }
-
-            Format::Raw => {
-                let writer = Box::new(file);
-                let encoder = Box::new(RawEncoder::new());
-
-                FileWriter::new(writer, encoder, notifier, metadata.clone())
-            }
-
-            Format::Txt => {
-                let writer = Box::new(file);
-                let encoder = Box::new(TextEncoder::new());
-
-                FileWriter::new(writer, encoder, notifier, metadata.clone())
-            }
-        };
-
-        Ok(Some(file_writer))
     }
 
     fn get_file_mode(&self, path: &Path) -> Result<(bool, bool)> {
@@ -261,7 +224,7 @@ impl cli::Session {
         let mut append = self.append;
 
         if path.exists() {
-            let metadata = fs::metadata(path)?;
+            let metadata = std::fs::metadata(path)?;
 
             if metadata.len() == 0 {
                 overwrite = true;
@@ -298,27 +261,58 @@ impl cli::Session {
         })
     }
 
-    fn open_output_file(&self, path: &Path, overwrite: bool, append: bool) -> Result<File> {
+    fn get_encoder(
-        if let Some(dir) = path.parent() {
+        &self,
-            let _ = fs::create_dir_all(dir);
+        format: Format,
+        path: &Path,
+        append: bool,
+    ) -> Result<Box<dyn Encoder + Send>> {
+        match format {
+            Format::AsciicastV3 => Ok(Box::new(AsciicastV3Encoder::new(append))),
+
+            Format::AsciicastV2 => {
+                let time_offset = if append {
+                    asciicast::get_duration(path)?
+                } else {
+                    0
+                };
+
+                Ok(Box::new(AsciicastV2Encoder::new(append, time_offset)))
             }
 
-        OpenOptions::new()
+            Format::Raw => Ok(Box::new(RawEncoder::new())),
+            Format::Txt => Ok(Box::new(TextEncoder::new())),
+        }
+    }
+
+    async fn open_output_file(
+        &self,
+        path: &Path,
+        overwrite: bool,
+        append: bool,
+    ) -> Result<tokio::fs::File> {
+        if let Some(dir) = path.parent() {
+            let _ = std::fs::create_dir_all(dir);
+        }
+
+        tokio::fs::File::options()
             .write(true)
             .append(append)
             .create(overwrite)
             .create_new(!overwrite && !append)
             .truncate(overwrite)
             .open(path)
+            .await
             .map_err(|e| e.into())
     }
 
-    fn get_listener(&self) -> Result<Option<TcpListener>> {
+    async fn get_listener(&self) -> Result<Option<TcpListener>> {
         let Some(addr) = self.stream_local else {
             return Ok(None);
         };
 
         TcpListener::bind(addr)
+            .await
             .map(Some)
             .context("cannot start listener")
     }
@@ -348,19 +342,19 @@ impl cli::Session {
         Ok(Some(relay))
     }
 
-    fn get_tty(&self, quiet: bool) -> Result<impl Tty> {
+    async fn get_tty(&self, quiet: bool) -> Result<Box<dyn Tty>> {
         let (cols, rows) = self.window_size.unwrap_or((None, None));
 
         if self.headless {
-            Ok(FixedSizeTty::new(NullTty::open()?, cols, rows))
+            Ok(Box::new(FixedSizeTty::new(NullTty, cols, rows)))
-        } else if let Ok(dev_tty) = DevTty::open() {
+        } else if let Ok(dev_tty) = DevTty::open().await {
-            Ok(FixedSizeTty::new(dev_tty, cols, rows))
+            Ok(Box::new(FixedSizeTty::new(dev_tty, cols, rows)))
         } else {
             if !quiet {
                 status::info!("TTY not available, recording in headless mode");
             }
 
-            Ok(FixedSizeTty::new(NullTty::open()?, cols, rows))
+            Ok(Box::new(FixedSizeTty::new(NullTty, cols, rows)))
         }
     }
 
@@ -384,8 +378,8 @@ impl cli::Session {
         Ok(())
     }
 
-    fn open_log_file(&self, path: &PathBuf) -> Result<File> {
+    fn open_log_file(&self, path: &PathBuf) -> Result<std::fs::File> {
-        OpenOptions::new()
+        std::fs::File::options()
             .create(true)
             .append(true)
             .open(path)
@@ -470,12 +464,14 @@ fn capture_env(var_names: Option<String>, config: &config::Recording) -> HashMap
         .collect::<HashMap<_, _>>()
 }
 
-fn get_notifier(config: &Config) -> Box<dyn Notifier> {
+fn get_notifier(config: &Config) -> BackgroundNotifier {
-    if config.notifications.enabled {
+    let inner = if config.notifications.enabled {
         notifier::get_notifier(config.notifications.command.clone())
     } else {
         Box::new(NullNotifier)
-    }
+    };
+
+    notifier::background(inner)
 }
 
 fn build_exec_command(command: Option<String>) -> Vec<String> {

src/fd.rs

@@ -0,0 +1,17 @@
+use std::io;
+use std::os::fd::AsFd;
+
+use nix::fcntl::{self, FcntlArg::*, OFlag};
+
+pub trait FdExt: AsFd {
+    fn set_nonblocking(&self) -> io::Result<()> {
+        let flags = fcntl::fcntl(self.as_fd(), F_GETFL)?;
+        let mut oflags = OFlag::from_bits_truncate(flags);
+        oflags |= OFlag::O_NONBLOCK;
+        fcntl::fcntl(self.as_fd(), F_SETFL(oflags))?;
+
+        Ok(())
+    }
+}
+
+impl<T: AsFd> FdExt for T {}

src/file_writer.rs

@@ -1,28 +1,30 @@
-use std::io::{self, Write};
 use std::time::UNIX_EPOCH;
 
+use async_trait::async_trait;
+use tokio::io::{self, AsyncWrite, AsyncWriteExt};
+
 use crate::asciicast;
-use crate::encoder;
+use crate::encoder::Encoder;
 use crate::notifier::Notifier;
 use crate::session::{self, Metadata};
 
 pub struct FileWriter {
-    writer: Box<dyn Write + Send>,
+    writer: Box<dyn AsyncWrite + Send + Unpin>,
-    encoder: Box<dyn encoder::Encoder + Send>,
+    encoder: Box<dyn Encoder + Send>,
     notifier: Box<dyn Notifier>,
     metadata: Metadata,
 }
 
 pub struct LiveFileWriter {
-    writer: Box<dyn Write + Send>,
+    writer: Box<dyn AsyncWrite + Send + Unpin>,
-    encoder: Box<dyn encoder::Encoder + Send>,
+    encoder: Box<dyn Encoder + Send>,
     notifier: Box<dyn Notifier>,
 }
 
 impl FileWriter {
     pub fn new(
-        writer: Box<dyn Write + Send>,
+        writer: Box<dyn AsyncWrite + Send + Unpin>,
-        encoder: Box<dyn encoder::Encoder + Send>,
+        encoder: Box<dyn Encoder + Send>,
         notifier: Box<dyn Notifier>,
         metadata: Metadata,
     ) -> Self {
@@ -34,7 +36,7 @@ impl FileWriter {
         }
     }
 
-    pub fn start(mut self) -> io::Result<LiveFileWriter> {
+    pub async fn start(mut self) -> io::Result<LiveFileWriter> {
         let timestamp = self
             .metadata
             .time
@@ -55,10 +57,11 @@ impl FileWriter {
             env: Some(self.metadata.env.clone()),
         };
 
-        if let Err(e) = self.writer.write_all(&self.encoder.header(&header)) {
+        if let Err(e) = self.writer.write_all(&self.encoder.header(&header)).await {
             let _ = self
                 .notifier
-                .notify("Write error, session won't be recorded".to_owned());
+                .notify("Write error, session won't be recorded".to_owned())
+                .await;
 
             return Err(e);
         }
@@ -71,23 +74,29 @@ impl FileWriter {
     }
 }
 
+#[async_trait]
 impl session::Output for LiveFileWriter {
-    fn event(&mut self, event: session::Event) -> io::Result<()> {
+    async fn event(&mut self, event: session::Event) -> io::Result<()> {
-        match self.writer.write_all(&self.encoder.event(event.into())) {
+        match self
+            .writer
+            .write_all(&self.encoder.event(event.into()))
+            .await
+        {
             Ok(_) => Ok(()),
 
             Err(e) => {
                 let _ = self
                     .notifier
-                    .notify("Write error, recording suspended".to_owned());
+                    .notify("Write error, recording suspended".to_owned())
+                    .await;
 
                 Err(e)
             }
         }
     }
 
-    fn flush(&mut self) -> io::Result<()> {
+    async fn flush(&mut self) -> io::Result<()> {
-        self.writer.write_all(&self.encoder.flush())
+        self.writer.write_all(&self.encoder.flush()).await
     }
 }
 

src/forwarder.rs

@@ -49,9 +49,9 @@ pub async fn forward<N: Notifier>(
             _ = time::sleep(Duration::from_secs(3)) => {
                 if reconnect_attempt > 0 {
                     if connection_count == 0 {
-                        let _ = notifier.notify("Connected to the server".to_string());
+                        let _ = notifier.notify("Connected to the server".to_string()).await;
                     } else {
-                        let _ = notifier.notify("Reconnected to the server".to_string());
+                        let _ = notifier.notify("Reconnected to the server".to_string()).await;
                     }
                 }
 
@@ -68,7 +68,10 @@ pub async fn forward<N: Notifier>(
             }
 
             Ok(false) => {
-                let _ = notifier.notify("Stream halted by the server".to_string());
+                let _ = notifier
+                    .notify("Stream halted by the server".to_string())
+                    .await;
+
                 break;
             }
 
@@ -82,7 +85,8 @@ pub async fn forward<N: Notifier>(
                     // This applies to asciinema-server v20241103 and earlier.
 
                     let _ = notifier
-                        .notify("The server version is too old, forwarding failed".to_string());
+                        .notify("The server version is too old, forwarding failed".to_string())
+                        .await;
 
                     break;
                 }
@@ -94,9 +98,11 @@ pub async fn forward<N: Notifier>(
                         // This happens when the server doesn't support our protocol (version).
                         // This applies to asciinema-server versions newer than v20241103.
 
-                        let _ = notifier.notify(
+                        let _ = notifier
+                            .notify(
                                 "CLI not compatible with the server, forwarding failed".to_string(),
-                        );
+                            )
+                            .await;
 
                         break;
                     }
@@ -107,10 +113,12 @@ pub async fn forward<N: Notifier>(
                 if reconnect_attempt == 0 {
                     if connection_count == 0 {
                         let _ = notifier
-                            .notify("Cannot connect to the server, retrying...".to_string());
+                            .notify("Cannot connect to the server, retrying...".to_string())
+                            .await;
                     } else {
                         let _ = notifier
-                            .notify("Disconnected from the server, reconnecting...".to_string());
+                            .notify("Disconnected from the server, reconnecting...".to_string())
+                            .await;
                     }
                 }
             }

src/io.rs

@@ -1,15 +0,0 @@
-use std::io;
-use std::os::fd::AsFd;
-
-use anyhow::Result;
-
-pub fn set_non_blocking<T: AsFd>(fd: &T) -> Result<(), io::Error> {
-    use nix::fcntl::{fcntl, FcntlArg::*, OFlag};
-
-    let flags = fcntl(fd, F_GETFL)?;
-    let mut oflags = OFlag::from_bits_truncate(flags);
-    oflags |= OFlag::O_NONBLOCK;
-    fcntl(fd, F_SETFL(oflags))?;
-
-    Ok(())
-}

src/main.rs

@@ -5,11 +5,11 @@ mod cli;
 mod cmd;
 mod config;
 mod encoder;
+mod fd;
 mod file_writer;
 mod forwarder;
 mod hash;
 mod html;
-mod io;
 mod leb128;
 mod locale;
 mod notifier;

src/notifier.rs

@@ -1,15 +1,16 @@
 use std::env;
 use std::ffi::OsStr;
 use std::path::PathBuf;
-use std::process::{Command, Stdio};
+use std::process::Stdio;
-use std::sync::mpsc;
-use std::thread;
 
-use anyhow::Result;
+use async_trait::async_trait;
+use tokio::process::Command;
+use tokio::sync::mpsc;
 use which::which;
 
+#[async_trait]
 pub trait Notifier: Send {
-    fn notify(&mut self, message: String) -> Result<()>;
+    async fn notify(&mut self, message: String) -> anyhow::Result<()>;
 }
 
 pub fn get_notifier(custom_command: Option<String>) -> Box<dyn Notifier> {
@@ -34,11 +35,12 @@ impl TmuxNotifier {
     }
 }
 
+#[async_trait]
 impl Notifier for TmuxNotifier {
-    fn notify(&mut self, message: String) -> Result<()> {
+    async fn notify(&mut self, message: String) -> anyhow::Result<()> {
         let args = ["display-message", &format!("asciinema: {message}")];
 
-        exec(&mut Command::new(&self.0), &args)
+        exec(&mut Command::new(&self.0), &args).await
     }
 }
 
@@ -50,9 +52,10 @@ impl LibNotifyNotifier {
     }
 }
 
+#[async_trait]
 impl Notifier for LibNotifyNotifier {
-    fn notify(&mut self, message: String) -> Result<()> {
+    async fn notify(&mut self, message: String) -> anyhow::Result<()> {
-        exec(&mut Command::new(&self.0), &["asciinema", &message])
+        exec(&mut Command::new(&self.0), &["asciinema", &message]).await
     }
 }
 
@@ -64,43 +67,48 @@ impl AppleScriptNotifier {
     }
 }
 
+#[async_trait]
 impl Notifier for AppleScriptNotifier {
-    fn notify(&mut self, message: String) -> Result<()> {
+    async fn notify(&mut self, message: String) -> anyhow::Result<()> {
         let text = message.replace('\"', "\\\"");
         let script = format!("display notification \"{text}\" with title \"asciinema\"");
 
-        exec(&mut Command::new(&self.0), &["-e", &script])
+        exec(&mut Command::new(&self.0), &["-e", &script]).await
     }
 }
 
 pub struct CustomNotifier(String);
 
+#[async_trait]
 impl Notifier for CustomNotifier {
-    fn notify(&mut self, text: String) -> Result<()> {
+    async fn notify(&mut self, text: String) -> anyhow::Result<()> {
         exec::<&str>(
             Command::new("/bin/sh")
                 .args(["-c", &self.0])
                 .env("TEXT", text),
             &[],
         )
+        .await
     }
 }
 
 pub struct NullNotifier;
 
+#[async_trait]
 impl Notifier for NullNotifier {
-    fn notify(&mut self, _text: String) -> Result<()> {
+    async fn notify(&mut self, _text: String) -> anyhow::Result<()> {
         Ok(())
     }
 }
 
-fn exec<S: AsRef<OsStr>>(command: &mut Command, args: &[S]) -> Result<()> {
+async fn exec<S: AsRef<OsStr>>(command: &mut Command, args: &[S]) -> anyhow::Result<()> {
     let status = command
         .stdin(Stdio::null())
         .stdout(Stdio::null())
         .stderr(Stdio::null())
         .args(args)
-        .status()?;
+        .status()
+        .await?;
 
     if status.success() {
         Ok(())
@@ -113,27 +121,28 @@ fn exec<S: AsRef<OsStr>>(command: &mut Command, args: &[S]) -> Result<()> {
 }
 
 #[derive(Clone)]
-pub struct ThreadedNotifier(mpsc::Sender<String>);
+pub struct BackgroundNotifier(mpsc::Sender<String>);
 
-pub fn threaded(mut notifier: Box<dyn Notifier>) -> ThreadedNotifier {
+pub fn background(mut notifier: Box<dyn Notifier>) -> BackgroundNotifier {
-    let (tx, rx) = mpsc::channel();
+    let (tx, mut rx) = mpsc::channel(16);
 
-    thread::spawn(move || {
+    tokio::spawn(async move {
-        for message in &rx {
+        while let Some(message) = rx.recv().await {
-            if notifier.notify(message).is_err() {
+            if notifier.notify(message).await.is_err() {
                 break;
             }
         }
 
-        for _ in rx {}
+        while rx.recv().await.is_some() {}
     });
 
-    ThreadedNotifier(tx)
+    BackgroundNotifier(tx)
 }
 
-impl Notifier for ThreadedNotifier {
+#[async_trait]
-    fn notify(&mut self, message: String) -> Result<()> {
+impl Notifier for BackgroundNotifier {
-        self.0.send(message)?;
+    async fn notify(&mut self, message: String) -> anyhow::Result<()> {
+        self.0.send(message).await?;
 
         Ok(())
     }

src/player.rs

@@ -1,14 +1,10 @@
-use std::io::{self, Write};
-use std::os::unix::io::AsRawFd;
-use std::time::{Duration, Instant};
-
 use anyhow::Result;
-use nix::sys::select::{pselect, FdSet};
+use tokio::sync::mpsc;
-use nix::sys::time::{TimeSpec, TimeValLike};
+use tokio::time::{self, Duration, Instant};
 
 use crate::asciicast::{self, Event, EventData};
 use crate::config::Key;
-use crate::tty::Tty;
+use crate::tty::{DevTty, Tty};
 
 pub struct KeyBindings {
     pub quit: Key,
@@ -28,62 +24,64 @@ impl Default for KeyBindings {
     }
 }
 
-pub fn play(
+pub async fn play(
-    recording: asciicast::Asciicast,
+    recording: asciicast::Asciicast<'static>,
-    mut tty: impl Tty,
     speed: f64,
-    idle_time_limit: Option<f64>,
+    idle_time_limit_override: Option<f64>,
     pause_on_markers: bool,
     keys: &KeyBindings,
     auto_resize: bool,
 ) -> Result<bool> {
     let initial_cols = recording.header.term_cols;
     let initial_rows = recording.header.term_rows;
-    let mut events = open_recording(recording, speed, idle_time_limit)?;
+    let mut events = emit_session_events(recording, speed, idle_time_limit_override)?;
-    let mut stdout = io::stdout();
     let mut epoch = Instant::now();
     let mut pause_elapsed_time: Option<u64> = None;
-    let mut next_event = events.next().transpose()?;
+    let mut next_event = events.recv().await.transpose()?;
+    let mut input = [0u8; 1024];
+    let mut tty = DevTty::open().await?;
 
     if auto_resize {
-        resize_terminal(&mut stdout, initial_cols, initial_rows)?;
+        tty.resize((initial_cols as usize, initial_rows as usize).into())
+            .await?;
     }
 
     while let Some(Event { time, data }) = &next_event {
         if let Some(pet) = pause_elapsed_time {
-            if let Some(input) = read_input(&mut tty, 1_000_000)? {
+            let n = tty.read(&mut input).await?;
-                if keys.quit.as_ref().is_some_and(|k| k == &input) {
+            let key = &input[..n];
-                    stdout.write_all("\r\n".as_bytes())?;
+
+            if keys.quit.as_ref().is_some_and(|k| k == key) {
+                tty.write_all("\r\n".as_bytes()).await?;
                 return Ok(false);
             }
 
-                if keys.pause.as_ref().is_some_and(|k| k == &input) {
+            if keys.pause.as_ref().is_some_and(|k| k == key) {
                 epoch = Instant::now() - Duration::from_micros(pet);
                 pause_elapsed_time = None;
-                } else if keys.step.as_ref().is_some_and(|k| k == &input) {
+            } else if keys.step.as_ref().is_some_and(|k| k == key) {
                 pause_elapsed_time = Some(*time);
 
                 match data {
                     EventData::Output(data) => {
-                            stdout.write_all(data.as_bytes())?;
+                        tty.write_all(data.as_bytes()).await?;
-                            stdout.flush()?;
                     }
 
                     EventData::Resize(cols, rows) if auto_resize => {
-                            resize_terminal(&mut stdout, *cols, *rows)?;
+                        tty.resize((*cols as usize, *rows as usize).into()).await?;
                     }
 
                     _ => {}
                 }
 
-                    next_event = events.next().transpose()?;
+                next_event = events.recv().await.transpose()?;
-                } else if keys.next_marker.as_ref().is_some_and(|k| k == &input) {
+            } else if keys.next_marker.as_ref().is_some_and(|k| k == key) {
                 while let Some(Event { time, data }) = next_event {
-                        next_event = events.next().transpose()?;
+                    next_event = events.recv().await.transpose()?;
 
                     match data {
                         EventData::Output(data) => {
-                                stdout.write_all(data.as_bytes())?;
+                            tty.write_all(data.as_bytes()).await?;
                         }
 
                         EventData::Marker(_) => {
@@ -92,30 +90,32 @@ pub fn play(
                         }
 
                         EventData::Resize(cols, rows) if auto_resize => {
-                                resize_terminal(&mut stdout, cols, rows)?;
+                            tty.resize((cols as usize, rows as usize).into()).await?;
                         }
 
                         _ => {}
                     }
                 }
-
-                    stdout.flush()?;
-                }
             }
         } else {
             while let Some(Event { time, data }) = &next_event {
                 let delay = *time as i64 - epoch.elapsed().as_micros() as i64;
 
                 if delay > 0 {
-                    stdout.flush()?;
+                    let delay = (*time as i64 - epoch.elapsed().as_micros() as i64).max(0) as u64;
 
-                    if let Some(key) = read_input(&mut tty, delay)? {
+                    if let Ok(result) =
-                        if keys.quit.as_ref().is_some_and(|k| k == &key) {
+                        time::timeout(Duration::from_micros(delay), tty.read(&mut input)).await
-                            stdout.write_all("\r\n".as_bytes())?;
+                    {
+                        let n = result?;
+                        let key = &input[..n];
+
+                        if keys.quit.as_ref().is_some_and(|k| k == key) {
+                            tty.write_all("\r\n".as_bytes()).await?;
                             return Ok(false);
                         }
 
-                        if keys.pause.as_ref().is_some_and(|k| k == &key) {
+                        if keys.pause.as_ref().is_some_and(|k| k == key) {
                             pause_elapsed_time = Some(epoch.elapsed().as_micros() as u64);
                             break;
                         }
@@ -126,17 +126,17 @@ pub fn play(
 
                 match data {
                     EventData::Output(data) => {
-                        stdout.write_all(data.as_bytes())?;
+                        tty.write_all(data.as_bytes()).await?;
                     }
 
                     EventData::Resize(cols, rows) if auto_resize => {
-                        resize_terminal(&mut stdout, *cols, *rows)?;
+                        tty.resize((*cols as usize, *rows as usize).into()).await?;
                     }
 
                     EventData::Marker(_) => {
                         if pause_on_markers {
                             pause_elapsed_time = Some(*time);
-                            next_event = events.next().transpose()?;
+                            next_event = events.recv().await.transpose()?;
                             break;
                         }
                     }
@@ -144,7 +144,7 @@ pub fn play(
                     _ => (),
                 }
 
-                next_event = events.next().transpose()?;
+                next_event = events.recv().await.transpose()?;
             }
         }
     }
@@ -152,56 +152,28 @@ pub fn play(
     Ok(true)
 }
 
-fn resize_terminal(stdout: &mut impl Write, cols: u16, rows: u16) -> io::Result<()> {
+fn emit_session_events(
-    let resize_sequence = format!("\x1b[8;{};{}t", rows, cols);
+    recording: asciicast::Asciicast<'static>,
-    stdout.write_all(resize_sequence.as_bytes())?;
-    stdout.flush()?;
-
-    Ok(())
-}
-
-fn open_recording(
-    recording: asciicast::Asciicast<'_>,
     speed: f64,
-    idle_time_limit: Option<f64>,
+    idle_time_limit_override: Option<f64>,
-) -> Result<impl Iterator<Item = Result<Event>> + '_> {
+) -> Result<mpsc::Receiver<Result<Event>>> {
-    let idle_time_limit = idle_time_limit
+    let idle_time_limit = idle_time_limit_override
         .or(recording.header.idle_time_limit)
         .unwrap_or(f64::MAX);
 
     let events = asciicast::limit_idle_time(recording.events, idle_time_limit);
     let events = asciicast::accelerate(events, speed);
+    // TODO avoid collect, support playback from stdin
+    let events: Vec<_> = events.collect();
+    let (tx, rx) = mpsc::channel::<Result<Event>>(1024);
 
-    Ok(events)
+    tokio::spawn(async move {
-}
+        for event in events {
-
+            if tx.send(event).await.is_err() {
-fn read_input<T: Tty>(tty: &mut T, timeout: i64) -> Result<Option<Vec<u8>>> {
-    let tty_fd = tty.as_fd();
-    let nfds = Some(tty_fd.as_raw_fd() + 1);
-    let mut rfds = FdSet::new();
-    rfds.insert(tty_fd);
-    let timeout = TimeSpec::microseconds(timeout);
-    let mut input: Vec<u8> = Vec::new();
-
-    pselect(nfds, &mut rfds, None, None, &timeout, None)?;
-
-    if rfds.contains(tty_fd) {
-        let mut buf = [0u8; 1024];
-
-        while let Ok(n) = tty.read(&mut buf) {
-            if n == 0 {
                 break;
             }
+        }
+    });
 
-            input.extend_from_slice(&buf[0..n]);
+    Ok(rx)
-        }
-
-        if !input.is_empty() {
-            Ok(Some(input))
-        } else {
-            Ok(None)
-        }
-    } else {
-        Ok(None)
-    }
 }

src/pty.rs

@@ -1,260 +1,95 @@
 use std::collections::HashMap;
 use std::env;
 use std::ffi::{CString, NulError};
-use std::fs::File;
+use std::os::fd::OwnedFd;
-use std::io::{self, ErrorKind, Read, Write};
-use std::os::fd::AsFd;
-use std::os::fd::{BorrowedFd, OwnedFd};
 use std::os::unix::io::AsRawFd;
-use std::sync::Arc;
-use std::time::{Duration, Instant};
 
-use anyhow::bail;
 use nix::errno::Errno;
-use nix::libc::EIO;
+use nix::pty::{ForkptyResult, Winsize};
-use nix::sys::select::{select, FdSet};
+use nix::sys::signal::{self, SigHandler, Signal};
-use nix::sys::signal::{self, kill, Signal};
 use nix::sys::wait::{self, WaitPidFlag, WaitStatus};
-use nix::unistd;
+use nix::unistd::{self, Pid};
 use nix::{libc, pty};
-use signal_hook::consts::{SIGALRM, SIGCHLD, SIGHUP, SIGINT, SIGQUIT, SIGTERM, SIGWINCH};
+use tokio::io::unix::AsyncFd;
-use signal_hook::SigId;
+use tokio::io::{self, Interest};
+use tokio::task;
 
-use crate::io::set_non_blocking;
+use crate::fd::FdExt;
-use crate::tty::{Tty, TtySize};
 
-type ExtraEnv = HashMap<String, String>;
+pub struct Pty {
-
+    child: Pid,
-pub trait Handler {
+    master: AsyncFd<OwnedFd>,
-    fn output(&mut self, time: Duration, data: &[u8]) -> bool;
-    fn input(&mut self, time: Duration, data: &[u8]) -> bool;
-    fn resize(&mut self, time: Duration, tty_size: TtySize) -> bool;
-    fn stop(&mut self, time: Duration, exit_status: i32);
 }
 
-pub fn open_signal_fd() -> anyhow::Result<SignalFd> {
+pub async fn spawn<S: AsRef<str>>(
-    SignalFd::open(&[SIGWINCH, SIGINT, SIGTERM, SIGQUIT, SIGHUP, SIGALRM, SIGCHLD])
-}
-
-pub fn exec<S: AsRef<str>, T: Tty, H: Handler>(
     command: &[S],
-    extra_env: &ExtraEnv,
+    winsize: Winsize,
-    initial_tty_size: TtySize,
+    extra_env: &HashMap<String, String>,
-    tty: &mut T,
+) -> anyhow::Result<Pty> {
-    handler: &mut H,
-    signal_fd: SignalFd,
-) -> anyhow::Result<i32> {
-    let winsize = initial_tty_size.into();
-    let epoch = Instant::now();
     let result = unsafe { pty::forkpty(Some(&winsize), None) }?;
 
     match result {
-        pty::ForkptyResult::Parent { child, master } => {
+        ForkptyResult::Parent { child, master } => {
-            let code = handle_parent(master, child, tty, handler, epoch, signal_fd)?;
+            master.set_nonblocking()?;
-            handler.stop(epoch.elapsed(), code);
+            let master = AsyncFd::new(master)?;
 
-            Ok(code)
+            Ok(Pty { child, master })
         }
 
-        pty::ForkptyResult::Child => {
+        ForkptyResult::Child => {
             handle_child(command, extra_env)?;
             unreachable!();
         }
     }
 }
 
-fn handle_parent<T: Tty, H: Handler>(
+impl Pty {
-    master_fd: OwnedFd,
+    pub async fn read(&self, buffer: &mut [u8]) -> io::Result<usize> {
-    child: unistd::Pid,
+        self.master
-    tty: &mut T,
+            .async_io(Interest::READABLE, |fd| match unistd::read(fd, buffer) {
-    handler: &mut H,
+                Ok(n) => Ok(n),
-    epoch: Instant,
+                Err(Errno::EIO) => Ok(0),
-    signal_fd: SignalFd,
+                Err(e) => Err(e.into()),
-) -> anyhow::Result<i32> {
+            })
-    let wait_result = match copy(master_fd, child, tty, handler, epoch, signal_fd) {
+            .await
-        Ok(Some(status)) => Ok(status),
-        Ok(None) => wait::waitpid(child, None),
-
-        Err(e) => {
-            let _ = wait::waitpid(child, None);
-            return Err(e);
-        }
-    };
-
-    match wait_result {
-        Ok(WaitStatus::Exited(_pid, status)) => Ok(status),
-        Ok(WaitStatus::Signaled(_pid, signal, ..)) => Ok(128 + signal as i32),
-        Ok(_) => Ok(1),
-        Err(e) => Err(anyhow::anyhow!(e)),
-    }
-}
-
-const BUF_SIZE: usize = 128 * 1024;
-
-fn copy<T: Tty, H: Handler>(
-    master_fd: OwnedFd,
-    child: unistd::Pid,
-    tty: &mut T,
-    handler: &mut H,
-    epoch: Instant,
-    mut signal_fd: SignalFd,
-) -> anyhow::Result<Option<WaitStatus>> {
-    let mut master = File::from(master_fd);
-    let master_raw_fd = master.as_raw_fd();
-    let mut buf = [0u8; BUF_SIZE];
-    let mut input: Vec<u8> = Vec::with_capacity(BUF_SIZE);
-    let mut output: Vec<u8> = Vec::with_capacity(BUF_SIZE);
-    let mut master_closed = false;
-
-    set_non_blocking(&master)?;
-
-    loop {
-        let master_fd = master.as_fd();
-        let tty_fd = tty.as_fd();
-        let mut rfds = FdSet::new();
-        let mut wfds = FdSet::new();
-
-        rfds.insert(tty_fd);
-        rfds.insert(signal_fd.as_fd());
-
-        if !master_closed {
-            rfds.insert(master_fd);
-
-            if !input.is_empty() {
-                wfds.insert(master_fd);
-            }
     }
 
-        if !output.is_empty() {
+    pub async fn write(&self, buffer: &[u8]) -> io::Result<usize> {
-            wfds.insert(tty_fd);
+        self.master
+            .async_io(Interest::WRITABLE, |fd| match unistd::write(fd, buffer) {
+                Ok(n) => Ok(n),
+                Err(Errno::EIO) => Ok(0),
+                Err(e) => Err(e.into()),
+            })
+            .await
     }
 
-        if let Err(e) = select(None, &mut rfds, &mut wfds, None, None) {
+    pub fn resize(&self, winsize: Winsize) {
-            if e == Errno::EINTR {
+        unsafe { libc::ioctl(self.master.as_raw_fd(), libc::TIOCSWINSZ, &winsize) };
-                continue;
     }
 
-            bail!(e);
+    pub fn kill(&self) {
-        }
-
-        let master_read = rfds.contains(master_fd);
-        let master_write = wfds.contains(master_fd);
-        let tty_read = rfds.contains(tty_fd);
-        let tty_write = wfds.contains(tty_fd);
-        let signal_read = rfds.contains(signal_fd.as_fd());
-
-        if master_read {
-            while let Some(n) = read_non_blocking(&mut master, &mut buf)? {
-                if n > 0 {
-                    if handler.output(epoch.elapsed(), &buf[0..n]) {
-                        output.extend_from_slice(&buf[0..n]);
-                    }
-                } else if output.is_empty() {
-                    return Ok(None);
-                } else {
-                    master_closed = true;
-                    break;
-                }
-            }
-        }
-
-        if master_write {
-            let mut buf: &[u8] = input.as_ref();
-
-            while let Some(n) = write_non_blocking(&mut master, buf)? {
-                buf = &buf[n..];
-
-                if buf.is_empty() {
-                    break;
-                }
-            }
-
-            let left = buf.len();
-
-            if left == 0 {
-                input.clear();
-            } else {
-                input.drain(..input.len() - left);
-            }
-        }
-
-        if tty_write {
-            let mut buf: &[u8] = output.as_ref();
-
-            while let Some(n) = write_non_blocking(tty, buf)? {
-                buf = &buf[n..];
-
-                if buf.is_empty() {
-                    break;
-                }
-            }
-
-            let left = buf.len();
-
-            if left == 0 {
-                if master_closed {
-                    return Ok(None);
-                }
-
-                output.clear();
-            } else {
-                output.drain(..output.len() - left);
-            }
-        }
-
-        if tty_read {
-            while let Some(n) = read_non_blocking(tty, &mut buf)? {
-                if n > 0 {
-                    if handler.input(epoch.elapsed(), &buf[0..n]) {
-                        input.extend_from_slice(&buf[0..n]);
-                    }
-                } else {
-                    return Ok(None);
-                }
-            }
-        }
-
-        let mut kill_the_child = false;
-
-        if signal_read {
-            for signal in signal_fd.flush() {
-                match signal {
-                    SIGWINCH => {
-                        let winsize = tty.get_size();
-
-                        if handler.resize(epoch.elapsed(), winsize.into()) {
-                            set_pty_size(master_raw_fd, &winsize);
-                        }
-                    }
-
-                    SIGINT | SIGTERM | SIGQUIT | SIGHUP => {
-                        kill_the_child = true;
-                    }
-
-                    SIGCHLD => {
-                        if let Ok(status) = wait::waitpid(child, Some(WaitPidFlag::WNOHANG)) {
-                            if status != WaitStatus::StillAlive {
-                                return Ok(Some(status));
-                            }
-                        }
-                    }
-
-                    _ => {}
-                }
-            }
-        }
-
-        if kill_the_child {
         // Any errors occurred when killing the child are ignored.
-            let _ = kill(child, Signal::SIGTERM);
+        let _ = signal::kill(self.child, Signal::SIGTERM);
-            return Ok(None);
     }
+
+    pub async fn wait(&self, options: Option<WaitPidFlag>) -> io::Result<WaitStatus> {
+        let pid = self.child;
+        task::spawn_blocking(move || Ok(wait::waitpid(pid, options)?)).await?
     }
 }
 
-fn handle_child<S: AsRef<str>>(command: &[S], extra_env: &ExtraEnv) -> anyhow::Result<()> {
+impl Drop for Pty {
-    use signal::SigHandler;
+    fn drop(&mut self) {
+        self.kill();
+        let _ = wait::waitpid(self.child, None);
+    }
+}
 
+fn handle_child<S: AsRef<str>>(
+    command: &[S],
+    extra_env: &HashMap<String, String>,
+) -> anyhow::Result<()> {
     let command = command
         .iter()
         .map(|s| CString::new(s.as_ref()))
@@ -269,166 +104,42 @@ fn handle_child<S: AsRef<str>>(command: &[S], extra_env: &ExtraEnv) -> anyhow::R
     unsafe { libc::_exit(1) }
 }
 
-fn set_pty_size(pty_fd: i32, winsize: &pty::Winsize) {
-    unsafe { libc::ioctl(pty_fd, libc::TIOCSWINSZ, winsize) };
-}
-
-fn read_non_blocking<R: Read + ?Sized>(
-    source: &mut R,
-    buf: &mut [u8],
-) -> io::Result<Option<usize>> {
-    match source.read(buf) {
-        Ok(n) => Ok(Some(n)),
-
-        Err(e) => {
-            if e.kind() == ErrorKind::WouldBlock {
-                Ok(None)
-            } else if e.raw_os_error().is_some_and(|code| code == EIO) {
-                Ok(Some(0))
-            } else {
-                return Err(e);
-            }
-        }
-    }
-}
-
-fn write_non_blocking<W: Write + ?Sized>(sink: &mut W, buf: &[u8]) -> io::Result<Option<usize>> {
-    match sink.write(buf) {
-        Ok(n) => Ok(Some(n)),
-
-        Err(e) => {
-            if e.kind() == ErrorKind::WouldBlock {
-                Ok(None)
-            } else if e.raw_os_error().is_some_and(|code| code == EIO) {
-                Ok(Some(0))
-            } else {
-                return Err(e);
-            }
-        }
-    }
-}
-
-pub struct SignalFd {
-    sigids: Vec<SigId>,
-    rx: OwnedFd,
-}
-
-impl SignalFd {
-    fn open(signals: &[libc::c_int]) -> anyhow::Result<Self> {
-        let (rx, tx) = unistd::pipe()?;
-        set_non_blocking(&rx)?;
-        set_non_blocking(&tx)?;
-
-        let tx = Arc::new(tx);
-
-        let mut sigids = Vec::new();
-
-        for signal in signals {
-            let tx_ = Arc::clone(&tx);
-            let num = *signal as u8;
-
-            let sigid = unsafe {
-                signal_hook::low_level::register(*signal, move || {
-                    let _ = unistd::write(&tx_, &[num]);
-                })
-            }?;
-
-            sigids.push(sigid);
-        }
-
-        Ok(Self { sigids, rx })
-    }
-
-    fn flush(&mut self) -> Vec<i32> {
-        let mut buf = [0; 256];
-        let mut signals = Vec::new();
-
-        while let Ok(n) = unistd::read(&self.rx, &mut buf) {
-            for num in &buf[..n] {
-                signals.push(*num as i32);
-            }
-
-            if n == 0 {
-                break;
-            };
-        }
-
-        signals
-    }
-}
-
-impl AsFd for SignalFd {
-    fn as_fd(&self) -> BorrowedFd<'_> {
-        self.rx.as_fd()
-    }
-}
-
-impl Drop for SignalFd {
-    fn drop(&mut self) {
-        for sigid in &self.sigids {
-            signal_hook::low_level::unregister(*sigid);
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests {
-    use super::{Handler, SignalFd};
+    use std::{collections::HashMap, sync::Arc};
-    use crate::pty::ExtraEnv;
-    use crate::tty::{NullTty, TtySize};
-    use std::time::Duration;
 
-    #[derive(Default)]
+    use super::Pty;
-    struct TestHandler {
+    use crate::tty::TtySize;
-        tty_size: TtySize,
+
-        output: Vec<Vec<u8>>,
+    async fn spawn<S: AsRef<str>>(command: &[S], extra_env: &HashMap<String, String>) -> Arc<Pty> {
+        Arc::new(
+            super::spawn(command, TtySize::default().into(), extra_env)
+                .await
+                .unwrap(),
+        )
     }
 
-    impl Handler for TestHandler {
+    async fn read_output(pty: Arc<Pty>) -> Vec<String> {
-        fn output(&mut self, _time: Duration, data: &[u8]) -> bool {
+        tokio::spawn(async move {
-            self.output.push(data.into());
+            let mut buf = [0u8; 1024];
+            let mut output = Vec::new();
 
-            true
+            while let Ok(n) = pty.read(&mut buf).await {
+                if n == 0 {
+                    break;
                 }
 
-        fn input(&mut self, _time: Duration, _data: &[u8]) -> bool {
+                output.push(String::from_utf8_lossy(&buf[..n]).to_string());
-            true
             }
 
-        fn resize(&mut self, _time: Duration, _size: TtySize) -> bool {
+            output
-            true
+        })
+        .await
+        .unwrap()
     }
 
-        fn stop(&mut self, _time: Duration, _exit_status: i32) {}
+    #[tokio::test]
-    }
+    async fn spawn_basic() {
-
-    impl TestHandler {
-        fn new() -> Self {
-            Self {
-                tty_size: Default::default(),
-                output: Vec::new(),
-            }
-        }
-
-        fn output(&self) -> Vec<String> {
-            self.output
-                .iter()
-                .map(|x| String::from_utf8_lossy(x).to_string())
-                .collect::<Vec<_>>()
-        }
-    }
-
-    fn setup() -> (TestHandler, SignalFd) {
-        let handler = TestHandler::new();
-        let signal_fd = super::open_signal_fd().unwrap();
-
-        (handler, signal_fd)
-    }
-
-    #[test]
-    fn exec_basic() {
-        let (mut handler, signal_fd) = setup();
-
         let code = r#"
 import sys;
 import time;
@@ -438,71 +149,36 @@ time.sleep(0.1);
 sys.stdout.write('bar');
 "#;
 
-        let _code = super::exec(
+        let pty = spawn(&["python3", "-c", code], &HashMap::new()).await;
-            &["python3", "-c", code],
+        let output = read_output(pty).await;
-            &ExtraEnv::new(),
-            TtySize::default(),
-            &mut NullTty::open().unwrap(),
-            &mut handler,
-            signal_fd,
-        )
-        .unwrap();
 
-        assert_eq!(handler.output(), vec!["foo", "bar"]);
+        assert_eq!(output, vec!["foo", "bar"]);
-        assert_eq!(handler.tty_size, TtySize(80, 24));
     }
 
-    #[test]
+    #[tokio::test]
-    fn exec_no_output() {
+    async fn spawn_no_output() {
-        let (mut handler, signal_fd) = setup();
+        let pty = spawn(&["true"], &HashMap::new()).await;
+        let output = read_output(pty).await;
 
-        let _code = super::exec(
+        assert!(output.is_empty());
-            &["true"],
-            &ExtraEnv::new(),
-            TtySize::default(),
-            &mut NullTty::open().unwrap(),
-            &mut handler,
-            signal_fd,
-        )
-        .unwrap();
-
-        assert!(handler.output().is_empty());
     }
 
-    #[test]
+    #[tokio::test]
-    fn exec_quick() {
+    async fn spawn_quick() {
-        let (mut handler, signal_fd) = setup();
+        let pty = spawn(&["printf", "hello world\n"], &HashMap::new()).await;
+        let output = read_output(pty).await;
 
-        let _code = super::exec(
+        assert!(!output.is_empty());
-            &["printf", "hello world\n"],
-            &ExtraEnv::new(),
-            TtySize::default(),
-            &mut NullTty::open().unwrap(),
-            &mut handler,
-            signal_fd,
-        )
-        .unwrap();
-
-        assert!(!handler.output().is_empty());
     }
 
-    #[test]
+    #[tokio::test]
-    fn exec_extra_env() {
+    async fn spawn_extra_env() {
-        let (mut handler, signal_fd) = setup();
+        let mut extra_env = HashMap::new();
+        extra_env.insert("ASCIINEMA_TEST_FOO".to_owned(), "bar".to_owned());
 
-        let mut env = ExtraEnv::new();
+        let pty = spawn(&["sh", "-c", "echo -n $ASCIINEMA_TEST_FOO"], &extra_env).await;
-        env.insert("ASCIINEMA_TEST_FOO".to_owned(), "bar".to_owned());
+        let output = read_output(pty).await;
 
-        let _code = super::exec(
+        assert_eq!(output, vec!["bar"]);
-            &["sh", "-c", "echo -n $ASCIINEMA_TEST_FOO"],
-            &env,
-            TtySize::default(),
-            &mut NullTty::open().unwrap(),
-            &mut handler,
-            signal_fd,
-        )
-        .unwrap();
-
-        assert_eq!(handler.output(), vec!["bar"]);
     }
 }

src/server.rs

@@ -34,13 +34,10 @@ struct AppState {
 }
 
 pub async fn serve(
-    listener: std::net::TcpListener,
+    listener: tokio::net::TcpListener,
     subscriber: Subscriber,
     shutdown_token: CancellationToken,
 ) -> io::Result<()> {
-    listener.set_nonblocking(true)?;
-    let listener = tokio::net::TcpListener::from_std(listener)?;
-
     let trace =
         TraceLayer::new_for_http().make_span_with(DefaultMakeSpan::default().include_headers(true));
 

src/session.rs

@@ -1,21 +1,24 @@
 use std::collections::HashMap;
-use std::io;
+use std::time::SystemTime;
-use std::sync::mpsc;
-use std::thread;
-use std::time::{Duration, SystemTime};
 
+use async_trait::async_trait;
+use futures_util::future;
+use futures_util::stream::StreamExt;
+use nix::sys::wait::{WaitPidFlag, WaitStatus};
+use signal_hook::consts::signal::*;
+use signal_hook_tokio::Signals;
+use tokio::io;
+use tokio::sync::mpsc;
+use tokio::time::Instant;
 use tracing::error;
 
 use crate::config::Key;
 use crate::notifier::Notifier;
-use crate::pty;
+use crate::pty::{self, Pty};
-use crate::tty::{TtySize, TtyTheme};
+use crate::tty::{Tty, TtySize, TtyTheme};
-use crate::util::{JoinHandle, Utf8Decoder};
+use crate::util::Utf8Decoder;
 
-pub trait Output: Send {
+const BUF_SIZE: usize = 128 * 1024;
-    fn event(&mut self, event: Event) -> io::Result<()>;
-    fn flush(&mut self) -> io::Result<()>;
-}
 
 #[derive(Clone)]
 pub enum Event {
@@ -26,20 +29,6 @@ pub enum Event {
     Exit(u64, i32),
 }
 
-pub struct Session<N> {
-    notifier: N,
-    input_decoder: Utf8Decoder,
-    output_decoder: Utf8Decoder,
-    tty_size: TtySize,
-    record_input: bool,
-    keys: KeyBindings,
-    sender: mpsc::Sender<Event>,
-    time_offset: u64,
-    pause_time: Option<u64>,
-    prefix_mode: bool,
-    _handle: JoinHandle,
-}
-
 #[derive(Clone)]
 pub struct Metadata {
     pub time: SystemTime,
@@ -58,85 +47,193 @@ pub struct TermInfo {
     pub theme: Option<TtyTheme>,
 }
 
-impl<N: Notifier> Session<N> {
+struct Session<N: Notifier> {
-    pub fn new(
+    epoch: Instant,
-        mut outputs: Vec<Box<dyn Output>>,
+    events_tx: mpsc::Sender<Event>,
-        tty_size: TtySize,
+    input_decoder: Utf8Decoder,
-        record_input: bool,
     keys: KeyBindings,
     notifier: N,
-    ) -> Self {
+    output_decoder: Utf8Decoder,
-        let (sender, receiver) = mpsc::channel::<Event>();
+    pause_time: Option<u64>,
+    prefix_mode: bool,
+    record_input: bool,
+    time_offset: u64,
+    tty_size: TtySize,
+}
 
-        let handle = thread::spawn(move || {
+#[async_trait]
-            for event in receiver {
+pub trait Output: Send {
-                outputs.retain_mut(|output| match output.event(event.clone()) {
+    async fn event(&mut self, event: Event) -> io::Result<()>;
-                    Ok(_) => true,
+    async fn flush(&mut self) -> io::Result<()>;
+}
 
-                    Err(e) => {
+pub async fn run<S: AsRef<str>, T: Tty + ?Sized, N: Notifier>(
-                        error!("output event handler failed: {e:?}");
+    command: &[S],
+    extra_env: &HashMap<String, String>,
+    tty: &mut T,
+    record_input: bool,
+    outputs: Vec<Box<dyn Output>>,
+    keys: KeyBindings,
+    notifier: N,
+) -> anyhow::Result<i32> {
+    let epoch = Instant::now();
+    let (events_tx, events_rx) = mpsc::channel::<Event>(1024);
+    let winsize = tty.get_size();
+    let pty = pty::spawn(command, winsize, extra_env).await?;
+    tokio::spawn(forward_events(events_rx, outputs));
 
-                        false
+    let mut session = Session {
-                    }
+        epoch,
-                });
+        events_tx,
+        input_decoder: Utf8Decoder::new(),
+        keys,
+        notifier,
+        output_decoder: Utf8Decoder::new(),
+        pause_time: None,
+        prefix_mode: false,
+        record_input,
+        time_offset: 0,
+        tty_size: winsize.into(),
+    };
+
+    session.run(pty, tty).await
+}
+
+async fn forward_events(mut events_rx: mpsc::Receiver<Event>, outputs: Vec<Box<dyn Output>>) {
+    let mut outputs = outputs;
+
+    while let Some(event) = events_rx.recv().await {
+        let futs: Vec<_> = outputs
+            .into_iter()
+            .map(|output| forward_event(output, event.clone()))
+            .collect();
+
+        outputs = future::join_all(futs).await.into_iter().flatten().collect();
     }
 
     for mut output in outputs {
-                match output.flush() {
+        if let Err(e) = output.flush().await {
-                    Ok(_) => {}
-
-                    Err(e) => {
             error!("output flush failed: {e:?}");
         }
     }
-            }
+}
-        });
 
-        Session {
+async fn forward_event(mut output: Box<dyn Output>, event: Event) -> Option<Box<dyn Output>> {
-            notifier,
+    match output.event(event).await {
-            input_decoder: Utf8Decoder::new(),
+        Ok(()) => Some(output),
-            output_decoder: Utf8Decoder::new(),
-            record_input,
-            keys,
-            tty_size,
-            sender,
-            time_offset: 0,
-            pause_time: None,
-            prefix_mode: false,
-            _handle: JoinHandle::new(handle),
-        }
-    }
 
-    fn elapsed_time(&self, time: Duration) -> u64 {
+        Err(e) => {
-        if let Some(pause_time) = self.pause_time {
+            error!("output event handler failed: {e:?}");
-            pause_time
+            None
-        } else {
-            time.as_micros() as u64 - self.time_offset
         }
     }
-
-    fn notify<S: ToString>(&mut self, text: S) {
-        self.notifier
-            .notify(text.to_string())
-            .expect("notification should succeed");
-    }
 }
 
-impl<N: Notifier> pty::Handler for Session<N> {
+impl<N: Notifier> Session<N> {
-    fn output(&mut self, time: Duration, data: &[u8]) -> bool {
+    async fn run<T: Tty + ?Sized>(&mut self, pty: Pty, tty: &mut T) -> anyhow::Result<i32> {
+        let mut signals =
+            Signals::new([SIGWINCH, SIGINT, SIGTERM, SIGQUIT, SIGHUP, SIGALRM, SIGCHLD])?;
+        let mut output_buf = [0u8; BUF_SIZE];
+        let mut input_buf = [0u8; BUF_SIZE];
+        let mut input: Vec<u8> = Vec::with_capacity(BUF_SIZE);
+        let mut output: Vec<u8> = Vec::with_capacity(BUF_SIZE);
+        let mut wait_status = None;
+
+        loop {
+            tokio::select! {
+                result = pty.read(&mut output_buf) => {
+                    let n = result?;
+
+                    if n > 0 {
+                        self.handle_output(&output_buf[..n]).await;
+                        output.extend_from_slice(&output_buf[0..n]);
+                    } else {
+                        break;
+                    }
+                }
+
+                result = pty.write(&input), if !input.is_empty() => {
+                    let n = result?;
+                    input.drain(..n);
+                }
+
+                result = tty.read(&mut input_buf) => {
+                    let n = result?;
+
+                    if n > 0 {
+                        if self.handle_input(&input_buf[..n]).await {
+                            input.extend_from_slice(&input_buf[..n]);
+                        }
+                    } else {
+                        break;
+                    }
+                }
+
+                result = tty.write(&output), if !output.is_empty() => {
+                    let n = result?;
+                    output.drain(..n);
+                }
+
+                Some(signal) = signals.next() => {
+                    match signal {
+                        SIGWINCH => {
+                            let winsize = tty.get_size();
+                            pty.resize(winsize);
+                            self.handle_resize(winsize.into()).await;
+                        }
+
+                        SIGINT | SIGTERM | SIGQUIT | SIGHUP => {
+                            pty.kill();
+                        }
+
+                        SIGCHLD => {
+                            if let Ok(status) = pty.wait(Some(WaitPidFlag::WNOHANG)).await {
+                                if status != WaitStatus::StillAlive {
+                                    wait_status = Some(status);
+                                    break;
+                                }
+                            }
+                        }
+
+                        _ => {}
+                    }
+                }
+            }
+        }
+
+        if !output.is_empty() {
+            self.handle_output(&output).await;
+            let _ = tty.write_all(&output).await;
+        }
+
+        let wait_status = match wait_status {
+            Some(ws) => ws,
+            None => pty.wait(None).await?,
+        };
+
+        let status = match wait_status {
+            WaitStatus::Exited(_pid, status) => status,
+            WaitStatus::Signaled(_pid, signal, ..) => 128 + signal as i32,
+            _ => 1,
+        };
+
+        self.handle_exit(status).await;
+
+        Ok(status)
+    }
+
+    async fn handle_output(&mut self, data: &[u8]) {
         if self.pause_time.is_none() {
             let text = self.output_decoder.feed(data);
 
             if !text.is_empty() {
-                let msg = Event::Output(self.elapsed_time(time), text);
+                let event = Event::Output(self.elapsed_time(), text);
-                self.sender.send(msg).expect("output send should succeed");
+                self.send_session_event(event).await;
+            }
         }
     }
 
-        true
+    async fn handle_input(&mut self, data: &[u8]) -> bool {
-    }
-
-    fn input(&mut self, time: Duration, data: &[u8]) -> bool {
         let prefix_key = self.keys.prefix.as_ref();
         let pause_key = self.keys.pause.as_ref();
         let add_marker_key = self.keys.add_marker.as_ref();
@@ -152,18 +249,18 @@ impl<N: Notifier> pty::Handler for Session<N> {
             if pause_key.is_some_and(|key| data == key) {
                 if let Some(pt) = self.pause_time {
                     self.pause_time = None;
-                    self.time_offset += self.elapsed_time(time) - pt;
+                    self.time_offset += self.elapsed_time() - pt;
-                    self.notify("Resumed recording");
+                    self.notify("Resumed recording").await;
                 } else {
-                    self.pause_time = Some(self.elapsed_time(time));
+                    self.pause_time = Some(self.elapsed_time());
-                    self.notify("Paused recording");
+                    self.notify("Paused recording").await;
                 }
 
                 return false;
             } else if add_marker_key.is_some_and(|key| data == key) {
-                let msg = Event::Marker(self.elapsed_time(time), "".to_owned());
+                let event = Event::Marker(self.elapsed_time(), "".to_owned());
-                self.sender.send(msg).expect("marker send should succeed");
+                self.send_session_event(event).await;
-                self.notify("Marker added");
+                self.notify("Marker added").await;
                 return false;
             }
         }
@@ -172,28 +269,47 @@ impl<N: Notifier> pty::Handler for Session<N> {
             let text = self.input_decoder.feed(data);
 
             if !text.is_empty() {
-                let msg = Event::Input(self.elapsed_time(time), text);
+                let event = Event::Input(self.elapsed_time(), text);
-                self.sender.send(msg).expect("input send should succeed");
+                self.send_session_event(event).await;
             }
         }
 
         true
     }
 
-    fn resize(&mut self, time: Duration, tty_size: TtySize) -> bool {
+    async fn handle_resize(&mut self, tty_size: TtySize) {
         if tty_size != self.tty_size {
-            let msg = Event::Resize(self.elapsed_time(time), tty_size);
+            let event = Event::Resize(self.elapsed_time(), tty_size);
-            self.sender.send(msg).expect("resize send should succeed");
+            self.send_session_event(event).await;
-
             self.tty_size = tty_size;
         }
-
-        true
     }
 
-    fn stop(&mut self, time: Duration, exit_status: i32) {
+    async fn handle_exit(&mut self, status: i32) {
-        let msg = Event::Exit(self.elapsed_time(time), exit_status);
+        let event = Event::Exit(self.elapsed_time(), status);
-        self.sender.send(msg).expect("exit send should succeed");
+        self.send_session_event(event).await;
+    }
+
+    fn elapsed_time(&self) -> u64 {
+        if let Some(pause_time) = self.pause_time {
+            pause_time
+        } else {
+            self.epoch.elapsed().as_micros() as u64 - self.time_offset
+        }
+    }
+
+    async fn send_session_event(&mut self, event: Event) {
+        self.events_tx
+            .send(event)
+            .await
+            .expect("session event send should succeed");
+    }
+
+    async fn notify<S: ToString>(&mut self, text: S) {
+        self.notifier
+            .notify(text.to_string())
+            .await
+            .expect("notification should succeed");
     }
 }
 

src/stream.rs

@@ -1,28 +1,23 @@
 use std::future;
-use std::io;
 use std::time::{Duration, Instant};
 
-use anyhow::Result;
+use async_trait::async_trait;
 use avt::Vt;
 use futures_util::{stream, StreamExt};
-use tokio::runtime::Handle;
 use tokio::sync::{broadcast, mpsc, oneshot};
-use tokio::time;
+use tokio::{io, time};
 use tokio_stream::wrappers::errors::BroadcastStreamRecvError;
 use tokio_stream::wrappers::BroadcastStream;
 use tracing::info;
 
 use crate::session::{self, Metadata};
-use crate::tty::TtySize;
+use crate::tty::{TtySize, TtyTheme};
-use crate::tty::TtyTheme;
 
 pub struct Stream {
     request_tx: mpsc::Sender<Request>,
     request_rx: mpsc::Receiver<Request>,
 }
 
-pub struct LiveStream(mpsc::UnboundedSender<session::Event>);
-
 type Request = oneshot::Sender<Subscription>;
 
 struct Subscription {
@@ -30,9 +25,6 @@ struct Subscription {
     events_rx: broadcast::Receiver<Event>,
 }
 
-#[derive(Clone)]
-pub struct Subscriber(mpsc::Sender<Request>);
-
 #[derive(Clone)]
 pub enum Event {
     Init(u64, u64, TtySize, Option<TtyTheme>, String),
@@ -43,9 +35,14 @@ pub enum Event {
     Exit(u64, u64, i32),
 }
 
+#[derive(Clone)]
+pub struct Subscriber(mpsc::Sender<Request>);
+
+pub struct LiveStream(mpsc::UnboundedSender<session::Event>);
+
 impl Stream {
     pub fn new() -> Self {
-        let (request_tx, request_rx) = mpsc::channel(1);
+        let (request_tx, request_rx) = mpsc::channel(16);
 
         Stream {
             request_tx,
@@ -57,18 +54,16 @@ impl Stream {
         Subscriber(self.request_tx.clone())
     }
 
-    pub fn start(self, handle: Handle, metadata: &Metadata) -> LiveStream {
+    pub async fn start(self, metadata: &Metadata) -> LiveStream {
         let (stream_tx, stream_rx) = mpsc::unbounded_channel();
         let request_rx = self.request_rx;
 
-        let fut = run(
+        tokio::spawn(run(
             metadata.term.size,
             metadata.term.theme.clone(),
             stream_rx,
             request_rx,
-        );
+        ));
-
-        handle.spawn(fut);
 
         LiveStream(stream_tx)
     }
@@ -162,7 +157,8 @@ async fn run(
 impl Subscriber {
     pub async fn subscribe(
         &self,
-    ) -> Result<impl futures_util::Stream<Item = Result<Event, BroadcastStreamRecvError>>> {
+    ) -> anyhow::Result<impl futures_util::Stream<Item = Result<Event, BroadcastStreamRecvError>>>
+    {
         let (tx, rx) = oneshot::channel();
         self.0.send(tx).await?;
         let subscription = time::timeout(Duration::from_secs(5), rx).await??;
@@ -179,12 +175,13 @@ fn build_vt(tty_size: TtySize) -> Vt {
         .build()
 }
 
+#[async_trait]
 impl session::Output for LiveStream {
-    fn event(&mut self, event: session::Event) -> io::Result<()> {
+    async fn event(&mut self, event: session::Event) -> io::Result<()> {
         self.0.send(event).map_err(io::Error::other)
     }
 
-    fn flush(&mut self) -> io::Result<()> {
+    async fn flush(&mut self) -> io::Result<()> {
         Ok(())
     }
 }

src/tty.rs

@@ -1,33 +1,70 @@
-use std::fs;
+use std::fs::File;
-use std::io;
+use std::future::pending;
-use std::os::fd::{AsFd, AsRawFd, BorrowedFd, OwnedFd};
+use std::io::{Read, Write};
+use std::os::fd::{AsFd, AsRawFd};
+use std::os::unix::fs::OpenOptionsExt;
 
-use anyhow::Result;
+use async_trait::async_trait;
-use nix::errno::Errno;
+use nix::libc;
-use nix::sys::select::{select, FdSet};
+use nix::pty::Winsize;
-use nix::sys::time::TimeVal;
+use nix::sys::termios::{self, SetArg, Termios};
-use nix::{libc, pty, unistd};
 use rgb::RGB8;
-use termion::raw::{IntoRawMode, RawTerminal};
+use tokio::io::unix::AsyncFd;
+use tokio::io::{self, Interest};
+use tokio::time::{self, Duration};
+
+const QUERY_READ_TIMEOUT: u64 = 500;
+const COLORS_QUERY: &str = "\x1b]10;?\x07\x1b]11;?\x07\x1b]4;0;?\x07\x1b]4;1;?\x07\x1b]4;2;?\x07\x1b]4;3;?\x07\x1b]4;4;?\x07\x1b]4;5;?\x07\x1b]4;6;?\x07\x1b]4;7;?\x07\x1b]4;8;?\x07\x1b]4;9;?\x07\x1b]4;10;?\x07\x1b]4;11;?\x07\x1b]4;12;?\x07\x1b]4;13;?\x07\x1b]4;14;?\x07\x1b]4;15;?\x07";
+const XTVERSION_QUERY: &str = "\x1b[>0q";
+
+pub struct DevTty {
+    file: AsyncFd<File>,
+    settings: libc::termios,
+}
+
+pub struct NullTty;
+
+pub struct FixedSizeTty<T> {
+    inner: T,
+    cols: Option<u16>,
+    rows: Option<u16>,
+}
 
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct TtySize(pub u16, pub u16);
 
+#[derive(Clone)]
+pub struct TtyTheme {
+    pub fg: RGB8,
+    pub bg: RGB8,
+    pub palette: Vec<RGB8>,
+}
+
+#[async_trait]
+pub trait Tty {
+    fn get_size(&self) -> Winsize;
+    async fn get_theme(&self) -> Option<TtyTheme>;
+    async fn get_version(&self) -> Option<String>;
+    async fn read<'e>(&self, buffer: &'e mut [u8]) -> io::Result<usize>;
+    async fn write<'e>(&self, buffer: &'e [u8]) -> io::Result<usize>;
+    async fn write_all<'e>(&self, buffer: &'e [u8]) -> io::Result<()>;
+}
+
 impl Default for TtySize {
     fn default() -> Self {
         TtySize(80, 24)
     }
 }
 
-impl From<pty::Winsize> for TtySize {
+impl From<Winsize> for TtySize {
-    fn from(winsize: pty::Winsize) -> Self {
+    fn from(winsize: Winsize) -> Self {
         TtySize(winsize.ws_col, winsize.ws_row)
     }
 }
 
-impl From<TtySize> for pty::Winsize {
+impl From<TtySize> for Winsize {
     fn from(tty_size: TtySize) -> Self {
-        pty::Winsize {
+        Winsize {
             ws_col: tty_size.0,
             ws_row: tty_size.1,
             ws_xpixel: 0,
@@ -48,62 +85,31 @@ impl From<TtySize> for (u16, u16) {
     }
 }
 
-pub trait Tty: io::Write + io::Read + AsFd {
-    fn get_size(&self) -> pty::Winsize;
-    fn get_theme(&self) -> Option<TtyTheme>;
-    fn get_version(&self) -> Option<String>;
-}
-
-#[derive(Clone)]
-pub struct TtyTheme {
-    pub fg: RGB8,
-    pub bg: RGB8,
-    pub palette: Vec<RGB8>,
-}
-
-pub struct DevTty {
-    file: RawTerminal<fs::File>,
-}
-
-const QUERY_READ_TIMEOUT: i64 = 500_000;
-
 impl DevTty {
-    pub fn open() -> Result<Self> {
+    pub async fn open() -> anyhow::Result<Self> {
-        let file = fs::OpenOptions::new()
+        let file = File::options()
             .read(true)
             .write(true)
-            .open("/dev/tty")?
+            .custom_flags(libc::O_NONBLOCK)
-            .into_raw_mode()?;
+            .open("/dev/tty")?;
 
-        crate::io::set_non_blocking(&file)?;
+        let file = AsyncFd::new(file)?;
+        let settings = make_raw(&file)?;
 
-        Ok(Self { file })
+        Ok(Self { file, settings })
     }
 
-    fn query(&self, query: &str) -> Result<Vec<u8>> {
+    async fn query(&self, query: &str) -> anyhow::Result<Vec<u8>> {
         let mut query = query.to_string().into_bytes();
         query.extend_from_slice(b"\x1b[c");
         let mut query = &query[..];
         let mut response = Vec::new();
         let mut buf = [0u8; 1024];
-        let fd = self.as_fd();
 
         loop {
-            let mut timeout = TimeVal::new(0, QUERY_READ_TIMEOUT);
+            tokio::select! {
-            let mut rfds = FdSet::new();
+                result = self.read(&mut buf) => {
-            let mut wfds = FdSet::new();
+                    let n = result?;
-            rfds.insert(fd);
-
-            if !query.is_empty() {
-                wfds.insert(fd);
-            }
-
-            match select(None, &mut rfds, &mut wfds, None, &mut timeout) {
-                Ok(0) => break,
-
-                Ok(_) => {
-                    if rfds.contains(fd) {
-                        let n = unistd::read(fd, &mut buf)?;
                     response.extend_from_slice(&buf[..n]);
 
                     if let Some(len) = self.complete_response_len(&response) {
@@ -112,18 +118,13 @@ impl DevTty {
                     }
                 }
 
-                    if wfds.contains(fd) {
+                result = self.write(query), if !query.is_empty() => {
-                        let n = unistd::write(fd, query)?;
+                    let n = result?;
                     query = &query[n..];
                 }
-                }
 
-                Err(e) => {
+                _ = time::sleep(Duration::from_millis(QUERY_READ_TIMEOUT)) => {
-                    if e == Errno::EINTR {
+                    break;
-                        continue;
-                    } else {
-                        return Err(e.into());
-                    }
                 }
             }
         }
@@ -159,6 +160,29 @@ impl DevTty {
             None
         }
     }
+
+    pub async fn resize(&mut self, size: TtySize) -> io::Result<()> {
+        let xtwinops_seq = format!("\x1b[8;{};{}t", size.1, size.0);
+        self.write_all(xtwinops_seq.as_bytes()).await?;
+
+        Ok(())
+    }
+}
+
+fn make_raw<F: AsFd>(fd: F) -> anyhow::Result<libc::termios> {
+    let termios = termios::tcgetattr(fd.as_fd())?;
+    let mut raw_termios = termios.clone();
+    termios::cfmakeraw(&mut raw_termios);
+    termios::tcsetattr(fd.as_fd(), SetArg::TCSANOW, &raw_termios)?;
+
+    Ok(termios.into())
+}
+
+impl Drop for DevTty {
+    fn drop(&mut self) {
+        let termios = Termios::from(self.settings);
+        let _ = termios::tcsetattr(self.file.as_fd(), SetArg::TCSANOW, &termios);
+    }
 }
 
 fn parse_color(rgb: &str) -> Option<RGB8> {
@@ -178,13 +202,10 @@ fn parse_color(rgb: &str) -> Option<RGB8> {
     Some(RGB8::new(r, g, b))
 }
 
-static COLORS_QUERY: &str = "\x1b]10;?\x07\x1b]11;?\x07\x1b]4;0;?\x07\x1b]4;1;?\x07\x1b]4;2;?\x07\x1b]4;3;?\x07\x1b]4;4;?\x07\x1b]4;5;?\x07\x1b]4;6;?\x07\x1b]4;7;?\x07\x1b]4;8;?\x07\x1b]4;9;?\x07\x1b]4;10;?\x07\x1b]4;11;?\x07\x1b]4;12;?\x07\x1b]4;13;?\x07\x1b]4;14;?\x07\x1b]4;15;?\x07";
+#[async_trait]
-
-static XTVERSION_QUERY: &str = "\x1b[>0q";
-
 impl Tty for DevTty {
-    fn get_size(&self) -> pty::Winsize {
+    fn get_size(&self) -> Winsize {
-        let mut winsize = pty::Winsize {
+        let mut winsize = Winsize {
             ws_row: 24,
             ws_col: 80,
             ws_xpixel: 0,
@@ -196,8 +217,8 @@ impl Tty for DevTty {
         winsize
     }
 
-    fn get_theme(&self) -> Option<TtyTheme> {
+    async fn get_theme(&self) -> Option<TtyTheme> {
-        let response = self.query(COLORS_QUERY).ok()?;
+        let response = self.query(COLORS_QUERY).await.ok()?;
         let response = String::from_utf8_lossy(response.as_slice());
         let mut colors = response.match_indices("rgb:");
         let (idx, _) = colors.next()?;
@@ -215,8 +236,8 @@ impl Tty for DevTty {
         Some(TtyTheme { fg, bg, palette })
     }
 
-    fn get_version(&self) -> Option<String> {
+    async fn get_version(&self) -> Option<String> {
-        let response = self.query(XTVERSION_QUERY).ok()?;
+        let response = self.query(XTVERSION_QUERY).await.ok()?;
 
         if let [b'\x1b', b'P', b'>', b'|', version @ .., b'\x1b', b'\\'] = &response[..] {
             Some(String::from_utf8_lossy(version).to_string())
@@ -224,46 +245,35 @@ impl Tty for DevTty {
             None
         }
     }
-}
 
-impl io::Read for DevTty {
+    async fn read<'e>(&self, buffer: &'e mut [u8]) -> io::Result<usize> {
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        self.file
-        self.file.read(buf)
+            .async_io(Interest::READABLE, |mut file| file.read(buffer))
-    }
+            .await
-}
+    }
-
+
-impl io::Write for DevTty {
+    async fn write<'e>(&self, buffer: &'e [u8]) -> io::Result<usize> {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.file
-        self.file.write(buf)
+            .async_io(Interest::WRITABLE, |mut file| file.write(buffer))
-    }
+            .await
-
+    }
-    fn flush(&mut self) -> io::Result<()> {
+
-        self.file.flush()
+    async fn write_all<'e>(&self, buffer: &'e [u8]) -> io::Result<()> {
-    }
+        let mut buffer = buffer;
-}
+
-
+        while !buffer.is_empty() {
-impl AsFd for DevTty {
+            let n = self.write(buffer).await?;
-    fn as_fd(&self) -> BorrowedFd<'_> {
+            buffer = &buffer[n..];
-        self.file.as_fd()
+        }
-    }
+
-}
+        Ok(())
-
-pub struct NullTty {
-    tx: OwnedFd,
-    _rx: OwnedFd,
-}
-
-impl NullTty {
-    pub fn open() -> Result<Self> {
-        let (rx, tx) = unistd::pipe()?;
-
-        Ok(Self { tx, _rx: rx })
     }
 }
 
+#[async_trait]
 impl Tty for NullTty {
-    fn get_size(&self) -> pty::Winsize {
+    fn get_size(&self) -> Winsize {
-        pty::Winsize {
+        Winsize {
             ws_row: 24,
             ws_col: 80,
             ws_xpixel: 0,
@@ -271,55 +281,37 @@ impl Tty for NullTty {
         }
     }
 
-    fn get_theme(&self) -> Option<TtyTheme> {
+    async fn get_theme(&self) -> Option<TtyTheme> {
         None
     }
 
-    fn get_version(&self) -> Option<String> {
+    async fn get_version(&self) -> Option<String> {
         None
     }
-}
 
-impl io::Read for NullTty {
+    async fn read<'e>(&self, _buffer: &'e mut [u8]) -> io::Result<usize> {
-    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> {
+        pending::<()>().await;
-        panic!("read attempt from NullTty");
+        unreachable!()
-    }
-}
-
-impl io::Write for NullTty {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        Ok(buf.len())
     }
 
-    fn flush(&mut self) -> io::Result<()> {
+    async fn write<'e>(&self, buffer: &'e [u8]) -> io::Result<usize> {
+        Ok(buffer.len())
+    }
+
+    async fn write_all<'e>(&self, _buffer: &'e [u8]) -> io::Result<()> {
         Ok(())
     }
 }
 
-impl AsFd for NullTty {
+impl<T: Tty> FixedSizeTty<T> {
-    fn as_fd(&self) -> BorrowedFd<'_> {
+    pub fn new(inner: T, cols: Option<u16>, rows: Option<u16>) -> Self {
-        self.tx.as_fd()
+        Self { inner, cols, rows }
     }
 }
 
-pub struct FixedSizeTty {
+#[async_trait]
-    inner: Box<dyn Tty>,
+impl<T: Tty + Sync> Tty for FixedSizeTty<T> {
-    cols: Option<u16>,
+    fn get_size(&self) -> Winsize {
-    rows: Option<u16>,
-}
-
-impl FixedSizeTty {
-    pub fn new<T: Tty + 'static>(inner: T, cols: Option<u16>, rows: Option<u16>) -> Self {
-        Self {
-            inner: Box::new(inner),
-            cols,
-            rows,
-        }
-    }
-}
-
-impl Tty for FixedSizeTty {
-    fn get_size(&self) -> pty::Winsize {
         let mut winsize = self.inner.get_size();
 
         if let Some(cols) = self.cols {
@@ -333,34 +325,24 @@ impl Tty for FixedSizeTty {
         winsize
     }
 
-    fn get_theme(&self) -> Option<TtyTheme> {
+    async fn get_theme(&self) -> Option<TtyTheme> {
-        self.inner.get_theme()
+        self.inner.get_theme().await
     }
 
-    fn get_version(&self) -> Option<String> {
+    async fn get_version(&self) -> Option<String> {
-        self.inner.get_version()
+        self.inner.get_version().await
-    }
-}
-
-impl AsFd for FixedSizeTty {
-    fn as_fd(&self) -> BorrowedFd<'_> {
-        return self.inner.as_fd();
-    }
-}
-
-impl io::Read for FixedSizeTty {
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        self.inner.read(buf)
-    }
-}
-
-impl io::Write for FixedSizeTty {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        self.inner.write(buf)
     }
 
-    fn flush(&mut self) -> io::Result<()> {
+    async fn read<'e>(&self, buffer: &'e mut [u8]) -> io::Result<usize> {
-        self.inner.flush()
+        self.inner.read(buffer).await
+    }
+
+    async fn write<'e>(&self, buffer: &'e [u8]) -> io::Result<usize> {
+        self.inner.write(buffer).await
+    }
+
+    async fn write_all<'e>(&self, buffer: &'e [u8]) -> io::Result<()> {
+        self.inner.write_all(buffer).await
     }
 }
 
@@ -396,12 +378,20 @@ mod tests {
     }
 
     #[test]
-    fn fixed_size_tty() {
+    fn fixed_size_tty_get_size() {
-        let tty = FixedSizeTty::new(NullTty::open().unwrap(), Some(100), Some(50));
+        let tty = FixedSizeTty::new(NullTty, Some(100), Some(50));
-
         let winsize = tty.get_size();
-
         assert!(winsize.ws_col == 100);
         assert!(winsize.ws_row == 50);
+
+        let tty = FixedSizeTty::new(NullTty, Some(100), None);
+        let winsize = tty.get_size();
+        assert!(winsize.ws_col == 100);
+        assert!(winsize.ws_row == 24);
+
+        let tty = FixedSizeTty::new(NullTty, None, None);
+        let winsize = tty.get_size();
+        assert!(winsize.ws_col == 80);
+        assert!(winsize.ws_row == 24);
     }
 }

src/util.rs

@@ -1,13 +1,13 @@
+use std::io;
 use std::path::{Path, PathBuf};
-use std::{io, thread};
 
-use anyhow::{anyhow, bail, Result};
+use anyhow::{anyhow, bail};
 use reqwest::Url;
 use tempfile::NamedTempFile;
 
 use crate::html;
 
-pub fn get_local_path(filename: &str) -> Result<Box<dyn AsRef<Path>>> {
+pub fn get_local_path(filename: &str) -> anyhow::Result<Box<dyn AsRef<Path>>> {
     if filename.starts_with("https://") || filename.starts_with("http://") {
         match download_asciicast(filename) {
             Ok(path) => Ok(Box::new(path)),
@@ -18,7 +18,7 @@ pub fn get_local_path(filename: &str) -> Result<Box<dyn AsRef<Path>>> {
     }
 }
 
-fn download_asciicast(url: &str) -> Result<NamedTempFile> {
+fn download_asciicast(url: &str) -> anyhow::Result<NamedTempFile> {
     use reqwest::blocking::get;
 
     let mut response = get(Url::parse(url)?)?;
@@ -50,24 +50,6 @@ fn download_asciicast(url: &str) -> Result<NamedTempFile> {
     }
 }
 
-pub struct JoinHandle(Option<thread::JoinHandle<()>>);
-
-impl JoinHandle {
-    pub fn new(handle: thread::JoinHandle<()>) -> Self {
-        Self(Some(handle))
-    }
-}
-
-impl Drop for JoinHandle {
-    fn drop(&mut self) {
-        self.0
-            .take()
-            .unwrap()
-            .join()
-            .expect("worker thread should finish cleanly");
-    }
-}
-
 pub struct Utf8Decoder(Vec<u8>);
 
 impl Utf8Decoder {