From f2b26479754ffa4e899e5aa670e6c107b8384aca Mon Sep 17 00:00:00 2001
From: oxalica <oxalicc@pm.me>
Date: Sat, 29 Apr 2023 11:12:41 +0800
Subject: [PATCH] Fix stuck on non-regular files and report loading errors

---
 Cargo.lock               | 14 +++++------
 crates/nil/Cargo.toml    |  4 +--
 crates/nil/src/server.rs | 53 +++++++++++++++++++++++++++++++++-------
 3 files changed, 53 insertions(+), 18 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 23b4a0c..cb9d4a5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -388,15 +388,15 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.141"
+version = "0.2.142"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3304a64d199bb964be99741b7a14d26972741915b3649639149b2479bb46f4b5"
+checksum = "6a987beff54b60ffa6d51982e1aa1146bc42f19bd26be28b0586f252fccf5317"
 
 [[package]]
 name = "linux-raw-sys"
-version = "0.3.1"
+version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d59d8c75012853d2e872fb56bc8a2e53718e2cafe1a4c823143141c6d90c322f"
+checksum = "b64f40e5e03e0d54f03845c8197d0291253cdbedfb1cb46b13c2c117554a9f4c"
 
 [[package]]
 name = "lock_api"
@@ -476,10 +476,10 @@ dependencies = [
  "atty",
  "codespan-reporting",
  "ide",
- "libc",
  "log",
  "lsp-types",
  "nix-interop",
+ "rustix",
  "serde_json",
  "slab",
  "syntax",
@@ -710,9 +710,9 @@ checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
 
 [[package]]
 name = "rustix"
-version = "0.37.11"
+version = "0.37.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "85597d61f83914ddeba6a47b3b8ffe7365107221c2e557ed94426489fefb5f77"
+checksum = "bc809f704c03a812ac71f22456c857be34185cac691a4316f27ab0f633bb9009"
 dependencies = [
  "bitflags",
  "errno",
diff --git a/crates/nil/Cargo.toml b/crates/nil/Cargo.toml
index bed693a..d158d5a 100644
--- a/crates/nil/Cargo.toml
+++ b/crates/nil/Cargo.toml
@@ -34,5 +34,5 @@ features = [
     "tracing-log",
 ]
 
-[target.'cfg(target_os = "linux")'.dependencies]
-libc = "0.2.137"
+[target.'cfg(unix)'.dependencies]
+rustix = { version = "0.37.17", default-features = false, features = ["fs"] }
diff --git a/crates/nil/src/server.rs b/crates/nil/src/server.rs
index 1ada182..e420667 100644
--- a/crates/nil/src/server.rs
+++ b/crates/nil/src/server.rs
@@ -26,6 +26,7 @@ use std::borrow::BorrowMut;
 use std::cell::Cell;
 use std::collections::HashMap;
 use std::future::{ready, Future};
+use std::io::{ErrorKind, Read};
 use std::ops::ControlFlow;
 use std::panic::UnwindSafe;
 use std::path::Path;
@@ -352,23 +353,57 @@ impl Server {
         tracing::debug!("Watched files changed: {params:?}");
 
         let mut flake_files_changed = true;
-        for FileEvent { uri, typ } in &params.changes {
+        for &FileEvent { ref uri, mut typ } in &params.changes {
             // Don't reload files maintained by the client.
             if self.opened_files.contains_key(uri) {
                 continue;
             }
             let Ok(path) = uri.to_file_path() else { continue };
-            match *typ {
-                FileChangeType::CREATED | FileChangeType::CHANGED => {
-                    if let Ok(text) = std::fs::read_to_string(&path) {
-                        self.set_vfs_file_content(uri, text);
+
+            if matches!(typ, FileChangeType::CREATED | FileChangeType::CHANGED) {
+                match (|| -> std::io::Result<_> {
+                    #[cfg(unix)]
+                    use rustix::fs::{fcntl_getfl, fcntl_setfl, OFlags, OpenOptionsExt};
+
+                    // Rule out non-regular files which may block `open()` infinitely
+                    // (eg. FIFO). We open it with `O_NONBLOCK` and check it before reading.
+                    let mut options = std::fs::File::options();
+                    options.read(true);
+                    #[cfg(unix)]
+                    options.custom_flags(OFlags::NONBLOCK.bits() as _);
+
+                    let mut file = options.open(&path)?;
+                    let ft = file.metadata()?.file_type();
+                    if !ft.is_file() {
+                        return Err(std::io::Error::new(
+                            std::io::ErrorKind::Other,
+                            format!("non-regular file type: {ft:?}"),
+                        ));
                     }
+
+                    // Remove the O_NONBLOCK flag for blocking read.
+                    #[cfg(unix)]
+                    {
+                        let flags = fcntl_getfl(&file)? - OFlags::NONBLOCK;
+                        fcntl_setfl(&file, flags)?;
+                    }
+
+                    let mut buf = String::new();
+                    file.read_to_string(&mut buf)?;
+                    Ok(buf)
+                })() {
+                    Ok(text) => self.set_vfs_file_content(uri, text),
+                    Err(err) if matches!(err.kind(), ErrorKind::NotFound) => {
+                        // File gets removed at the time calling `open()`.
+                        typ = FileChangeType::DELETED;
+                    }
+                    Err(err) => tracing::error!("Ignore file {path:?}: {err}"),
                 }
-                FileChangeType::DELETED => {
-                    let _: Result<_> = self.vfs.write().unwrap().remove_uri(uri);
-                }
-                _ => continue,
             }
+            if typ == FileChangeType::DELETED {
+                let _: Result<_> = self.vfs.write().unwrap().remove_uri(uri);
+            }
+
             if let Ok(relative) = path.strip_prefix(&self.config.root_path) {
                 if relative == Path::new(FLAKE_FILE) || relative == Path::new(FLAKE_LOCK_FILE) {
                     flake_files_changed = true;