Use Bytes instead of Vec for more performant data copying between TTY and PTY

Cargo.lock

@@ -90,6 +90,7 @@ dependencies = [
  "async-trait",
  "avt",
  "axum",
+ "bytes",
  "clap",
  "clap_complete",
  "clap_mangen",

Cargo.toml

@@ -43,6 +43,7 @@ tokio-util = { version = "0.7", features = ["rt"] }
 rand = "0.9"
 async-trait = "0.1"
 signal-hook-tokio = { version = "0.3", features = ["futures-v0_3"] }
+bytes = "1.0"
 
 [build-dependencies]
 clap = { version = "4.0", features = ["derive", "wrap_help"] }

src/session.rs

@@ -2,6 +2,7 @@ use std::collections::HashMap;
 use std::time::SystemTime;
 
 use async_trait::async_trait;
+use bytes::{Buf, BytesMut};
 use futures_util::future;
 use futures_util::stream::StreamExt;
 use nix::sys::wait::{WaitPidFlag, WaitStatus};
@@ -135,8 +136,8 @@ impl<N: Notifier> Session<N> {
             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 input = BytesMut::with_capacity(BUF_SIZE);
+        let mut output = BytesMut::with_capacity(BUF_SIZE);
         let mut wait_status = None;
 
         loop {
@@ -154,7 +155,7 @@ impl<N: Notifier> Session<N> {
 
                 result = pty.write(&input), if !input.is_empty() => {
                     let n = result?;
-                    input.drain(..n);
+                    input.advance(n);
                 }
 
                 result = tty.read(&mut input_buf) => {
@@ -171,7 +172,7 @@ impl<N: Notifier> Session<N> {
 
                 result = tty.write(&output), if !output.is_empty() => {
                     let n = result?;
-                    output.drain(..n);
+                    output.advance(n);
                 }
 
                 Some(signal) = signals.next() => {

src/tty/macos.rs

@@ -11,6 +11,8 @@ use std::os::fd::{AsFd, AsRawFd, BorrowedFd, OwnedFd};
 use std::os::unix::fs::OpenOptionsExt;
 use std::thread;
 
+use bytes::{Buf, BytesMut};
+
 use async_trait::async_trait;
 use nix::errno::Errno;
 use nix::pty::Winsize;
@@ -135,7 +137,7 @@ fn copy<F: AsFd, G: AsFd>(src_fd: F, dst_fd: G) {
     let src_fd = src_fd.as_fd();
     let dst_fd = dst_fd.as_fd();
     let mut buf = [0u8; BUF_SIZE];
-    let mut data = Vec::with_capacity(BUF_SIZE);
+    let mut data = BytesMut::with_capacity(BUF_SIZE);
 
     loop {
         let mut read_fds = select::FdSet::new();
@@ -177,7 +179,7 @@ fn copy<F: AsFd, G: AsFd>(src_fd: F, dst_fd: G) {
         if write_fds.contains(dst_fd) {
             match unistd::write(dst_fd, &data) {
                 Ok(n) => {
-                    data.drain(..n);
+                    data.advance(n);
                 }
 
                 Err(Errno::EWOULDBLOCK) => {}
@@ -211,7 +213,7 @@ fn copy<F: AsFd, G: AsFd>(src_fd: F, dst_fd: G) {
 
         match unistd::write(dst_fd, &data) {
             Ok(n) => {
-                data.drain(..n);
+                data.advance(n);
             }
 
             Err(Errno::EWOULDBLOCK) => {}