[io/file_watcher] Ensure start/stop file watching requests are run on dart thread.
At present start/stop requests are scheduled on RunLoop thread.
This results in deadlocks since same RunLoop thread might be busy
with blocking writes of file watching events, not giving a chance
for Dart to read previously-written events. Reading would unblock
writer.
So this CL moves start/stop requests to run on Dart thread instead.
Fixes https://github.com/dart-lang/sdk/issues/45996
TEST=run analysis_server against flutter_gallery github-backed folder, switch between branches and ensure analyze_server remains responsive
Change-Id: I0464eeecf8e46ba3027fa0ed21cc323495d965c3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/201442
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
diff --git a/runtime/bin/file_system_watcher_macos.cc b/runtime/bin/file_system_watcher_macos.cc
index b73c0d13..88d6986 100644
--- a/runtime/bin/file_system_watcher_macos.cc
+++ b/runtime/bin/file_system_watcher_macos.cc
@@ -82,81 +82,36 @@
void set_ref(FSEventStreamRef ref) { ref_ = ref; }
void Start() {
- // Schedule StartCallback to be executed in the RunLoop.
- CFRunLoopTimerContext context;
- memset(&context, 0, sizeof(context));
- context.info = this;
- CFRunLoopTimerRef timer =
- CFRunLoopTimerCreate(NULL, 0, 0, 0, 0, Node::StartCallback, &context);
- CFRunLoopAddTimer(watcher_->run_loop_, timer, kCFRunLoopCommonModes);
- CFRelease(timer);
- watcher_->monitor_.Enter();
- while (!ready_) {
- watcher_->monitor_.Wait(Monitor::kNoTimeout);
- }
- watcher_->monitor_.Exit();
- }
-
- static void StartCallback(CFRunLoopTimerRef timer, void* info) {
- Node* node = reinterpret_cast<Node*>(info);
- ASSERT(Thread::Compare(node->watcher_->threadId_,
- Thread::GetCurrentThreadId()));
FSEventStreamContext context;
memset(&context, 0, sizeof(context));
- context.info = reinterpret_cast<void*>(node);
+ context.info = reinterpret_cast<void*>(this);
CFArrayRef array = CFArrayCreate(
- NULL, reinterpret_cast<const void**>(&node->path_ref_), 1, NULL);
+ NULL, reinterpret_cast<const void**>(&path_ref_), 1, NULL);
FSEventStreamRef ref = FSEventStreamCreate(
NULL, Callback, &context, array, kFSEventStreamEventIdSinceNow, 0.10,
kFSEventStreamCreateFlagFileEvents);
CFRelease(array);
- node->set_ref(ref);
+ set_ref(ref);
+ ready_.store(true, std::memory_order_release);
- FSEventStreamScheduleWithRunLoop(node->ref_, node->watcher_->run_loop_,
+ FSEventStreamScheduleWithRunLoop(ref_, watcher_->run_loop_,
kCFRunLoopDefaultMode);
- FSEventStreamStart(node->ref_);
- FSEventStreamFlushSync(node->ref_);
-
- node->watcher_->monitor_.Enter();
- node->ready_ = true;
- node->watcher_->monitor_.Notify();
- node->watcher_->monitor_.Exit();
+ FSEventStreamStart(ref_);
+ FSEventStreamFlushSync(ref_);
}
void Stop() {
- // Schedule StopCallback to be executed in the RunLoop.
ASSERT(ready_);
- CFRunLoopTimerContext context;
- memset(&context, 0, sizeof(context));
- context.info = this;
- CFRunLoopTimerRef timer =
- CFRunLoopTimerCreate(NULL, 0, 0, 0, 0, StopCallback, &context);
- CFRunLoopAddTimer(watcher_->run_loop_, timer, kCFRunLoopCommonModes);
- CFRelease(timer);
- watcher_->monitor_.Enter();
- while (ready_) {
- watcher_->monitor_.Wait(Monitor::kNoTimeout);
- }
- watcher_->monitor_.Exit();
- }
-
- static void StopCallback(CFRunLoopTimerRef timer, void* info) {
- Node* node = reinterpret_cast<Node*>(info);
- ASSERT(Thread::Compare(node->watcher_->threadId_,
- Thread::GetCurrentThreadId()));
- FSEventStreamStop(node->ref_);
- FSEventStreamInvalidate(node->ref_);
- FSEventStreamRelease(node->ref_);
- node->watcher_->monitor_.Enter();
- node->ready_ = false;
- node->watcher_->monitor_.Notify();
- node->watcher_->monitor_.Exit();
+ FSEventStreamStop(ref_);
+ FSEventStreamInvalidate(ref_);
+ FSEventStreamRelease(ref_);
+ ready_.store(false, std::memory_order_release);
}
FSEventsWatcher* watcher() const { return watcher_; }
- bool ready() const { return ready_; }
+ bool ready() const { return ready_.load(std::memory_order_acquire); }
intptr_t base_path_length() const { return base_path_length_; }
int read_fd() const { return read_fd_; }
int write_fd() const { return write_fd_; }
@@ -164,7 +119,7 @@
private:
FSEventsWatcher* watcher_;
- bool ready_;
+ std::atomic<bool> ready_;
intptr_t base_path_length_;
CFStringRef path_ref_;
int read_fd_;
@@ -266,8 +221,6 @@
Node* node = reinterpret_cast<Node*>(client);
ASSERT(Thread::Compare(node->watcher()->threadId_,
Thread::GetCurrentThreadId()));
- // `ready` is set on same thread as this callback is invoked, so we don't
- // need to lock here.
if (!node->ready()) {
return;
}
