| /* |
| * Copyright (C) 2010, Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH |
| * DAMAGE. |
| */ |
| |
| #ifndef DeferredTaskHandler_h |
| #define DeferredTaskHandler_h |
| |
| #include "modules/ModulesExport.h" |
| #include "platform/heap/Handle.h" |
| #include "wtf/HashSet.h" |
| #include "wtf/PassRefPtr.h" |
| #include "wtf/RefPtr.h" |
| #include "wtf/ThreadSafeRefCounted.h" |
| #include "wtf/Threading.h" |
| #include "wtf/ThreadingPrimitives.h" |
| #include "wtf/Vector.h" |
| #include "wtf/build_config.h" |
| |
| namespace blink { |
| |
| class BaseAudioContext; |
| class OfflineAudioContext; |
| class AudioHandler; |
| class AudioNodeOutput; |
| class AudioSummingJunction; |
| |
| // DeferredTaskHandler manages the major part of pre- and post- rendering tasks, |
| // and provides a lock mechanism against the audio rendering graph. A |
| // DeferredTaskHandler object is created when an BaseAudioContext object is |
| // created. |
| // |
| // DeferredTaskHandler outlives the BaseAudioContext only if all of the |
| // following conditions match: |
| // - An audio rendering thread is running, |
| // - It is requested to stop, |
| // - The audio rendering thread calls requestToDeleteHandlersOnMainThread(), |
| // - It posts a task of deleteHandlersOnMainThread(), and |
| // - GC happens and it collects the BaseAudioContext before the task execution. |
| // |
| class MODULES_EXPORT DeferredTaskHandler final |
| : public ThreadSafeRefCounted<DeferredTaskHandler> { |
| public: |
| static PassRefPtr<DeferredTaskHandler> create(); |
| ~DeferredTaskHandler(); |
| |
| void handleDeferredTasks(); |
| void contextWillBeDestroyed(); |
| |
| // BaseAudioContext can pull node(s) at the end of each render quantum even |
| // when they are not connected to any downstream nodes. These two methods are |
| // called by the nodes who want to add/remove themselves into/from the |
| // automatic pull lists. |
| void addAutomaticPullNode(AudioHandler*); |
| void removeAutomaticPullNode(AudioHandler*); |
| // Called right before handlePostRenderTasks() to handle nodes which need to |
| // be pulled even when they are not connected to anything. |
| void processAutomaticPullNodes(size_t framesToProcess); |
| |
| // Keep track of AudioNode's that have their channel count mode changed. We |
| // process the changes in the post rendering phase. |
| void addChangedChannelCountMode(AudioHandler*); |
| void removeChangedChannelCountMode(AudioHandler*); |
| |
| // Keep track of AudioNode's that have their channel interpretation |
| // changed. We process the changes in the post rendering phase. |
| void addChangedChannelInterpretation(AudioHandler*); |
| void removeChangedChannelInterpretation(AudioHandler*); |
| |
| // Only accessed when the graph lock is held. |
| void markSummingJunctionDirty(AudioSummingJunction*); |
| // Only accessed when the graph lock is held. Must be called on the main |
| // thread. |
| void removeMarkedSummingJunction(AudioSummingJunction*); |
| |
| void markAudioNodeOutputDirty(AudioNodeOutput*); |
| void removeMarkedAudioNodeOutput(AudioNodeOutput*); |
| |
| // In AudioNode::breakConnection() and deref(), a tryLock() is used for |
| // calling actual processing, but if it fails keep track here. |
| void addDeferredBreakConnection(AudioHandler&); |
| void breakConnections(); |
| |
| void addRenderingOrphanHandler(PassRefPtr<AudioHandler>); |
| void requestToDeleteHandlersOnMainThread(); |
| void clearHandlersToBeDeleted(); |
| |
| // |
| // Thread Safety and Graph Locking: |
| // |
| void setAudioThreadToCurrentThread(); |
| ThreadIdentifier audioThread() const { return acquireLoad(&m_audioThread); } |
| |
| // TODO(hongchan): Use no-barrier load here. (crbug.com/247328) |
| // |
| // It is okay to use a relaxed (no-barrier) load here. Because the data |
| // referenced by m_audioThread is not actually being used, thus we do not |
| // need a barrier between the load of m_audioThread and of that data. |
| bool isAudioThread() const { |
| return currentThread() == acquireLoad(&m_audioThread); |
| } |
| |
| void lock(); |
| bool tryLock(); |
| void unlock(); |
| |
| // This locks the audio render thread for OfflineAudioContext rendering. |
| // MUST NOT be used in the real-time audio context. |
| void offlineLock(); |
| |
| #if ENABLE(ASSERT) |
| // Returns true if this thread owns the context's lock. |
| bool isGraphOwner(); |
| #endif |
| |
| class MODULES_EXPORT AutoLocker { |
| STACK_ALLOCATED(); |
| |
| public: |
| explicit AutoLocker(DeferredTaskHandler& handler) : m_handler(handler) { |
| m_handler.lock(); |
| } |
| explicit AutoLocker(BaseAudioContext*); |
| |
| ~AutoLocker() { m_handler.unlock(); } |
| |
| private: |
| DeferredTaskHandler& m_handler; |
| }; |
| |
| // This is for locking offline render thread (which is considered as the |
| // audio thread) with unlocking on self-destruction at the end of the scope. |
| // Also note that it uses lock() rather than tryLock() because the timing |
| // MUST be accurate on offline rendering. |
| class MODULES_EXPORT OfflineGraphAutoLocker { |
| STACK_ALLOCATED(); |
| |
| public: |
| explicit OfflineGraphAutoLocker(OfflineAudioContext*); |
| |
| ~OfflineGraphAutoLocker() { m_handler.unlock(); } |
| |
| private: |
| DeferredTaskHandler& m_handler; |
| }; |
| |
| private: |
| DeferredTaskHandler(); |
| void updateAutomaticPullNodes(); |
| void updateChangedChannelCountMode(); |
| void updateChangedChannelInterpretation(); |
| void handleDirtyAudioSummingJunctions(); |
| void handleDirtyAudioNodeOutputs(); |
| void deleteHandlersOnMainThread(); |
| |
| // For the sake of thread safety, we maintain a seperate Vector of automatic |
| // pull nodes for rendering in m_renderingAutomaticPullNodes. It will be |
| // copied from m_automaticPullNodes by updateAutomaticPullNodes() at the |
| // very start or end of the rendering quantum. |
| HashSet<AudioHandler*> m_automaticPullNodes; |
| Vector<AudioHandler*> m_renderingAutomaticPullNodes; |
| // m_automaticPullNodesNeedUpdating keeps track if m_automaticPullNodes is |
| // modified. |
| bool m_automaticPullNodesNeedUpdating; |
| |
| // Collection of nodes where the channel count mode has changed. We want the |
| // channel count mode to change in the pre- or post-rendering phase so as |
| // not to disturb the running audio thread. |
| HashSet<AudioHandler*> m_deferredCountModeChange; |
| |
| HashSet<AudioHandler*> m_deferredChannelInterpretationChange; |
| |
| // These two HashSet must be accessed only when the graph lock is held. |
| // These raw pointers are safe because their destructors unregister them. |
| HashSet<AudioSummingJunction*> m_dirtySummingJunctions; |
| HashSet<AudioNodeOutput*> m_dirtyAudioNodeOutputs; |
| |
| // Only accessed in the audio thread. |
| Vector<AudioHandler*> m_deferredBreakConnectionList; |
| |
| Vector<RefPtr<AudioHandler>> m_renderingOrphanHandlers; |
| Vector<RefPtr<AudioHandler>> m_deletableOrphanHandlers; |
| |
| // Graph locking. |
| RecursiveMutex m_contextGraphMutex; |
| volatile ThreadIdentifier m_audioThread; |
| }; |
| |
| } // namespace blink |
| |
| #endif // DeferredTaskHandler_h |