Claude experiment (#34577)

Release Notes:

- N/A

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>
Co-authored-by: Anthony Eid <hello@anthonyeid.me>
Co-authored-by: Ben Brandt <benjamin.j.brandt@gmail.com>
Co-authored-by: Nathan Sobo <nathan@zed.dev>
Co-authored-by: Oleksiy Syvokon <oleksiy.syvokon@gmail.com>

crates/nc/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "nc"
+version = "0.1.0"
+edition.workspace = true
+publish.workspace = true
+license = "GPL-3.0-or-later"
+
+[lints]
+workspace = true
+
+[lib]
+path = "src/nc.rs"
+doctest = false
+
+[dependencies]
+anyhow.workspace = true
+futures.workspace = true
+net.workspace = true
+smol.workspace = true
+workspace-hack.workspace = true

crates/nc/LICENSE-GPL

@@ -0,0 +1 @@
+../../LICENSE-GPL

crates/nc/src/nc.rs

@@ -0,0 +1,56 @@
+use anyhow::Result;
+
+#[cfg(windows)]
+pub fn main(_socket: &str) -> Result<()> {
+    // It looks like we can't get an async stdio stream on Windows from smol.
+    //
+    // We decided to merge this with a panic on Windows since this is only used
+    // by the experimental Claude Code Agent Server.
+    //
+    // We're tracking this internally, and we will address it before shipping the integration.
+    panic!("--nc isn't yet supported on Windows");
+}
+
+/// The main function for when Zed is running in netcat mode
+#[cfg(not(windows))]
+pub fn main(socket: &str) -> Result<()> {
+    use futures::{AsyncReadExt as _, AsyncWriteExt as _, FutureExt as _, io::BufReader, select};
+    use net::async_net::UnixStream;
+    use smol::{Async, io::AsyncBufReadExt};
+
+    smol::block_on(async {
+        let socket_stream = UnixStream::connect(socket).await?;
+        let (socket_read, mut socket_write) = socket_stream.split();
+        let mut socket_reader = BufReader::new(socket_read);
+
+        let mut stdout = Async::new(std::io::stdout())?;
+        let stdin = Async::new(std::io::stdin())?;
+        let mut stdin_reader = BufReader::new(stdin);
+
+        let mut socket_line = Vec::new();
+        let mut stdin_line = Vec::new();
+
+        loop {
+            select! {
+                bytes_read = socket_reader.read_until(b'\n', &mut socket_line).fuse() => {
+                    if bytes_read? == 0 {
+                        break
+                    }
+                    stdout.write_all(&socket_line).await?;
+                    stdout.flush().await?;
+                    socket_line.clear();
+                }
+                bytes_read = stdin_reader.read_until(b'\n', &mut stdin_line).fuse() => {
+                    if bytes_read? == 0 {
+                        break
+                    }
+                    socket_write.write_all(&stdin_line).await?;
+                    socket_write.flush().await?;
+                    stdin_line.clear();
+                }
+            }
+        }
+
+        anyhow::Ok(())
+    })
+}