Forward stdin if it's piped on Linux and MacOS

Author: fredizzimo

Cargo.lock

@@ -168,15 +168,16 @@ objc2-metal = { version = "0.3.1", default-features = false, features = [
 skia-safe = { version = "0.88.0", features = ["metal", "gl", "textlayout"] }
 uzers = "0.12.1"
 
-
 [target.'cfg(not(any(target_os = "windows", target_os = "macos")))'.dependencies]
 skia-safe = { version = "0.88.0", features = ["gl", "textlayout"] }
 
-
 [target.'cfg(any(target_os = "windows", target_os = "macos"))'.dependencies]
 csscolorparser = "0.7.0"
 shlex = "1.3.0"
 
+[target.'cfg(not(target_os = "windows"))'.dependencies]
+rustix = "1.0.8"
+
 [target.'cfg(target_os = "windows")'.build-dependencies]
 winres = "0.1.12"
 

Cargo.toml

@@ -110,7 +110,8 @@ async fn launch(
 ) -> Result<NeovimSession> {
     let neovim_instance = neovim_instance(settings.as_ref()).await?;
 
-    let session = NeovimSession::new(neovim_instance, handler)
+    #[allow(unused_mut)]
+    let mut session = NeovimSession::new(neovim_instance, handler)
         .await
         .context("Could not locate or start neovim process")?;
 
@@ -153,6 +154,14 @@ async fn launch(
     options.set_linegrid_external(true);
     options.set_multigrid_external(!cmdline_settings.no_multi_grid);
     options.set_rgb(true);
+    // We can close the handle here, as Neovim already owns it
+    #[cfg(not(target_os = "windows"))]
+    if let Some(fd) = session.stdin_fd.take() {
+        use rustix::fd::AsRawFd;
+        if let Ok(fd) = fd.as_raw_fd().try_into() {
+            options.set_stdin_fd(fd);
+        }
+    }
 
     // Triggers loading the user config
 

src/bridge/mod.rs

@@ -29,6 +29,8 @@ pub struct NeovimSession {
     pub io_handle: JoinHandle<std::result::Result<(), Box<LoopError>>>,
     pub neovim_process: Option<Child>,
     pub stderr_task: Option<JoinHandle<Vec<String>>>,
+    #[cfg(not(target_os = "windows"))]
+    pub stdin_fd: Option<rustix::fd::OwnedFd>,
 }
 
 #[cfg(debug_assertions)]
@@ -45,6 +47,10 @@ impl NeovimSession {
         instance: NeovimInstance,
         handler: impl Handler<Writer = NeovimWriter>,
     ) -> anyhow::Result<Self> {
+        // This needs to be done before the process is spawned, since the file descriptors are
+        // inherited on unix-like systems
+        #[cfg(not(target_os = "windows"))]
+        let stdin_fd = instance.forward_stdin();
         let (reader, writer, stderr_reader, neovim_process) = instance.connect().await?;
         // Spawn a background task to read from stderr
         let stderr_task = stderr_reader.map(|reader| {
@@ -84,6 +90,8 @@ impl NeovimSession {
                     io_handle,
                     neovim_process,
                     stderr_task,
+                    #[cfg(not(target_os = "windows"))]
+                    stdin_fd,
                 })
             }
         }
@@ -120,7 +128,6 @@ impl NeovimInstance {
         mut cmd: Command,
     ) -> Result<(BoxedReader, BoxedWriter, Option<BoxedReader>, Option<Child>)> {
         log::debug!("Starting neovim with: {cmd:?}");
-
         let mut child = cmd
             .stdin(Stdio::piped())
             .stdout(Stdio::piped())
@@ -177,6 +184,20 @@ impl NeovimInstance {
         }
     }
 
+    #[cfg(not(target_os = "windows"))]
+    fn forward_stdin(&self) -> Option<rustix::fd::OwnedFd> {
+        use std::io::IsTerminal;
+        // stdin should be forwarded only in embedded mode when stdio is piped
+        match self {
+            Self::Embedded(..) => {
+                let stdin = std::io::stdin();
+                let is_pipe = !stdin.is_terminal();
+                is_pipe.then(|| rustix::io::dup(stdin).ok()).flatten()
+            }
+            Self::Server { .. } => None,
+        }
+    }
+
     fn split(
         stream: impl AsyncRead + AsyncWrite + Send + Unpin + 'static,
     ) -> (BoxedReader, BoxedWriter) {