Change audio render thread checking to use new AudioRendererSink::BelongsToRendererThread()

media/audio/audio_device_thread.cc

 // Copyright (c) 2012 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 "media/audio/audio_device_thread.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
 #include <limits>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/aligned_memory.h"
 #include "base/message_loop/message_loop.h"
 #include "base/numerics/safe_conversions.h"
+#include "base/synchronization/lock.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "media/base/audio_bus.h"
 
 using base::PlatformThread;
 
 namespace media {
 
 // The actual worker thread implementation.  It's very bare bones and much
 // simpler than SimpleThread (no synchronization in Start, etc) and supports
 // joining the thread handle asynchronously via a provided message loop even
 // after the Thread object itself has been deleted.
 class AudioDeviceThread::Thread
     : public PlatformThread::Delegate,
       public base::RefCountedThreadSafe<AudioDeviceThread::Thread> {
  public:
   Thread(AudioDeviceThread::Callback* callback,
          base::SyncSocket::Handle socket,
          const char* thread_name,
          bool synchronized_buffers);
 
   void Start();
 
   // Stops the thread.  If |loop_for_join| is non-NULL, the function posts
   // a task to join (close) the thread handle later instead of waiting for
   // the thread.  If loop_for_join is NULL, then the function waits
   // synchronously for the thread to terminate.
   void Stop(base::MessageLoop* loop_for_join);
 
+  // Returns true if called on the device thread, otherwise false.
+  bool BelongsToRenderingThread();
+
  private:
   friend class base::RefCountedThreadSafe<AudioDeviceThread::Thread>;
   ~Thread() override;
 
   // Overrides from PlatformThread::Delegate.
   void ThreadMain() override;
 
   // Runs the loop that reads from the socket.
   void Run();
 
  private:
   base::PlatformThreadHandle thread_;
   AudioDeviceThread::Callback* callback_;
   base::CancelableSyncSocket socket_;
   base::Lock callback_lock_;
   const char* thread_name_;
   const bool synchronized_buffers_;
 
+#if DCHECK_IS_ON()
+  base::PlatformThreadRef device_thread_id_;
+  base::Lock device_thread_id_lock_;
+#endif
+
   DISALLOW_COPY_AND_ASSIGN(Thread);
 };
 
 // AudioDeviceThread implementation
 
 AudioDeviceThread::AudioDeviceThread() {
 }
 
 AudioDeviceThread::~AudioDeviceThread() { DCHECK(!thread_.get()); }
 
@@ skipping 14 matching lines @@
     thread_->Stop(loop_for_join);
     thread_ = NULL;
   }
 }
 
 bool AudioDeviceThread::IsStopped() {
   base::AutoLock auto_lock(thread_lock_);
   return !thread_.get();
 }
 
+bool AudioDeviceThread::BelongsToRenderingThread() {

[DaleCurtis, 2016/06/10 18:24:49]

Instead of hopping through two locks, it seems like AudioDeviceThread should
just store a ref to the thread id directly. see base::Thread for an example of
how they do this.

[Henrik Grunell, 2016/06/13 12:46:15]

base::Thread corresponds to ADT::Thread. We can replace the lock with an event
there.

Here we still need to ask ATD::Thread about the right thread (or get the ID). We
could store the ID here, but that data still needs to be protected by a lock
since we must clear it in Stop(), to be able to get a new after next Start().
(If you still think it's doable, that's great, could you be more specific on
how?)

I changed the first, removing one lock. Note that the change requires approval
by jam@ or brettw@.

+  base::AutoLock auto_lock(thread_lock_);
+  return thread_.get() ? thread_->BelongsToRenderingThread() : false;
+}
+
 // AudioDeviceThread::Thread implementation
 AudioDeviceThread::Thread::Thread(AudioDeviceThread::Callback* callback,
                                   base::SyncSocket::Handle socket,
                                   const char* thread_name,
                                   bool synchronized_buffers)
     : thread_(),
       callback_(callback),
       socket_(socket),
       thread_name_(thread_name),
       synchronized_buffers_(synchronized_buffers) {
@@ skipping 28 matching lines @@
   if (!thread.is_null()) {
     if (loop_for_join) {
       loop_for_join->PostTask(FROM_HERE,
           base::Bind(&base::PlatformThread::Join, thread));
     } else {
       base::PlatformThread::Join(thread);
     }
   }
 }
 
+bool AudioDeviceThread::Thread::BelongsToRenderingThread() {
+#if DCHECK_IS_ON()

[DaleCurtis, 2016/06/10 18:24:49]

Only ThreadCheckers disable for DCHECK, typically BelongsToXXXThread do not, so
I think this should always be available. I could be convinced otherwise since we
don't have a message loop though.

[Henrik Grunell, 2016/06/13 12:46:15]

OK, that's fine I think. Done.

+  base::AutoLock auto_lock(device_thread_id_lock_);
+  return device_thread_id_ == PlatformThread::CurrentRef();
+#else
+  return true;
+#endif
+}
+
 void AudioDeviceThread::Thread::ThreadMain() {
+#if DCHECK_IS_ON()
+  base::AutoLock auto_lock(device_thread_id_lock_);
+  device_thread_id_ = PlatformThread::CurrentRef();
+#endif
+
   PlatformThread::SetName(thread_name_);
 
   // Singleton access is safe from this thread as long as callback is non-NULL.
   // The callback is the only point where the thread calls out to 'unknown' code
   // that might touch singletons and the lifetime of the callback is controlled
   // by another thread on which singleton access is OK as well.
   base::ThreadRestrictions::SetSingletonAllowed(true);
 
   {  // NOLINT
     base::AutoLock auto_lock(callback_lock_);
@@ skipping 74 matching lines @@
 }
 
 AudioDeviceThread::Callback::~Callback() {}
 
 void AudioDeviceThread::Callback::InitializeOnAudioThread() {
   MapSharedMemory();
   CHECK(shared_memory_.memory());
 }
 
 }  // namespace media.