1 files changed, 47 insertions, 0 deletions
diff --git a/gn/util/msg_loop.h b/gn/util/msg_loop.h
new file mode 100644
index 00000000000..267d2a9f681
--- /dev/null
+++ b/gn/util/msg_loop.h
@@ -0,0 +1,47 @@
+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UTIL_RUN_LOOP_H_
+#define UTIL_RUN_LOOP_H_
+
+#include "base/macros.h"
+#include "util/task.h"
+
+#include <condition_variable>
+#include <mutex>
+#include <queue>
+
+class MsgLoop {
+ public:
+  MsgLoop();
+  ~MsgLoop();
+
+  // Blocks until PostQuit() is called, processing work items posted via
+  void Run();
+
+  // Schedules Run() to exit, but will not happen until other outstanding tasks
+  // complete. Can be called from any thread.
+  void PostQuit();
+
+  // Posts a work item to this queue. All items will be run on the thread from
+  // which Run() was called. Can be called from any thread.
+  void PostTask(Task task);
+
+  // Run()s until the queue is empty. Should only be used (carefully) in tests.
+  void RunUntilIdleForTesting();
+
+  // Gets the MsgLoop for the thread from which it's called, or nullptr if
+  // there's no MsgLoop for the current thread.
+  static MsgLoop* Current();
+
+ private:
+  std::mutex queue_mutex_;
+  std::queue<Task> task_queue_;
+  std::condition_variable notifier_;
+  bool should_quit_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(MsgLoop);
+};
+
+#endif  // UTIL_RUN_LOOP_H_