Add MessageLoop::AssertIdle(). Use in ChromeOS audio threads.

base/message_loop.cc

 // Copyright (c) 2010 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.
 
 #include "base/message_loop.h"
 
 #include <algorithm>
 
 #include "base/compiler_specific.h"
 #include "base/lazy_instance.h"
@@ skipping 268 matching lines @@
 void MessageLoop::AddTaskObserver(TaskObserver* task_observer) {
   DCHECK_EQ(this, current());
   task_observers_.AddObserver(task_observer);
 }
 
 void MessageLoop::RemoveTaskObserver(TaskObserver* task_observer) {
   DCHECK_EQ(this, current());
   task_observers_.RemoveObserver(task_observer);
 }
 
+void MessageLoop::AssertIdle() const {
+  base::AutoLock lock(incoming_queue_lock_);
+  DCHECK(incoming_queue_.empty());

[darin (slow to review), 2011/01/25 17:07:43]

what about the work_queue_?

[willchan no longer on Chromium, 2011/01/25 17:12:01]

See my comment in the .h file:
// Asserts that the MessageLoop is "idle". in reality, we only check
// |incoming_queue_|, since we don't want to lock |work_queue_|.

|work_queue_| is only ever touched on the thread the MessageLoop runs on, so
unless I want to add a bunch of locks, I think it's unsafe to access. I am
concerned that an unlocked .empty() operation on |work_queue_| may lead to
crashes, although I guess that's implementation specific.

+}
+
 //------------------------------------------------------------------------------
 
 // Runs the loop in two different SEH modes:
 // enable_SEH_restoration_ = false : any unhandled exception goes to the last
 // one that calls SetUnhandledExceptionFilter().
 // enable_SEH_restoration_ = true : any unhandled exception goes to the filter
 // that was existed before the loop was run.
 void MessageLoop::RunHandler() {
 #if defined(OS_WIN)
   if (exception_restoration_) {
@@ skipping 397 matching lines @@
                                            Watcher *delegate) {
   return pump_libevent()->WatchFileDescriptor(
       fd,
       persistent,
       static_cast<base::MessagePumpLibevent::Mode>(mode),
       controller,
       delegate);
 }
 
 #endif