include/gui/StreamSplitter.h - platform/frameworks/native - Git at Google

 /*
  * Copyright 2014 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #ifndef ANDROID_GUI_STREAMSPLITTER_H
 #define ANDROID_GUI_STREAMSPLITTER_H

 #include <gui/IConsumerListener.h>
 #include <gui/IProducerListener.h>

 #include <utils/Condition.h>
 #include <utils/KeyedVector.h>
 #include <utils/Mutex.h>
 #include <utils/StrongPointer.h>

 namespace android {

 class GraphicBuffer;
 class IGraphicBufferConsumer;
 class IGraphicBufferProducer;

 // StreamSplitter is an autonomous class that manages one input BufferQueue
 // and multiple output BufferQueues. By using the buffer attach and detach logic
 // in BufferQueue, it is able to present the illusion of a single split
 // BufferQueue, where each buffer queued to the input is available to be
 // acquired by each of the outputs, and is able to be dequeued by the input
 // again only once all of the outputs have released it.
 class StreamSplitter : public BnConsumerListener {
 public:
     // createSplitter creates a new splitter, outSplitter, using inputQueue as
     // the input BufferQueue. Output BufferQueues must be added using addOutput
     // before queueing any buffers to the input.
     //
     // A return value other than NO_ERROR means that an error has occurred and
     // outSplitter has not been modified. BAD_VALUE is returned if inputQueue or
     // outSplitter is NULL. See IGraphicBufferConsumer::consumerConnect for
     // explanations of other error codes.
     static status_t createSplitter(const sp<IGraphicBufferConsumer>& inputQueue,
             sp<StreamSplitter>* outSplitter);

     // addOutput adds an output BufferQueue to the splitter. The splitter
     // connects to outputQueue as a CPU producer, and any buffers queued
     // to the input will be queued to each output. It is assumed that all of the
     // outputs are added before any buffers are queued on the input. If any
     // output is abandoned by its consumer, the splitter will abandon its input
     // queue (see onAbandoned).
     //
     // A return value other than NO_ERROR means that an error has occurred and
     // outputQueue has not been added to the splitter. BAD_VALUE is returned if
     // outputQueue is NULL. See IGraphicBufferProducer::connect for explanations
     // of other error codes.
     status_t addOutput(const sp<IGraphicBufferProducer>& outputQueue);

     // setName sets the consumer name of the input queue
     void setName(const String8& name);

 private:
     // From IConsumerListener
     //
     // During this callback, we store some tracking information, detach the
     // buffer from the input, and attach it to each of the outputs. This call
     // can block if there are too many outstanding buffers. If it blocks, it
     // will resume when onBufferReleasedByOutput releases a buffer back to the
     // input.
     virtual void onFrameAvailable(const BufferItem& item);

     // From IConsumerListener
     // We don't care about released buffers because we detach each buffer as
     // soon as we acquire it. See the comment for onBufferReleased below for
     // some clarifying notes about the name.
     virtual void onBuffersReleased() {}

     // From IConsumerListener
     // We don't care about sideband streams, since we won't be splitting them
     virtual void onSidebandStreamChanged() {}

     // This is the implementation of the onBufferReleased callback from
     // IProducerListener. It gets called from an OutputListener (see below), and
     // 'from' is which producer interface from which the callback was received.
     //
     // During this callback, we detach the buffer from the output queue that
     // generated the callback, update our state tracking to see if this is the
     // last output releasing the buffer, and if so, release it to the input.
     // If we release the buffer to the input, we allow a blocked
     // onFrameAvailable call to proceed.
     void onBufferReleasedByOutput(const sp<IGraphicBufferProducer>& from);

     // When this is called, the splitter disconnects from (i.e., abandons) its
     // input queue and signals any waiting onFrameAvailable calls to wake up.
     // It still processes callbacks from other outputs, but only detaches their
     // buffers so they can continue operating until they run out of buffers to
     // acquire. This must be called with mMutex locked.
     void onAbandonedLocked();

     // This is a thin wrapper class that lets us determine which BufferQueue
     // the IProducerListener::onBufferReleased callback is associated with. We
     // create one of these per output BufferQueue, and then pass the producer
     // into onBufferReleasedByOutput above.
     class OutputListener : public BnProducerListener,
                            public IBinder::DeathRecipient {
     public:
         OutputListener(const sp<StreamSplitter>& splitter,
                 const sp<IGraphicBufferProducer>& output);
         virtual ~OutputListener();

         // From IProducerListener
         virtual void onBufferReleased();

         // From IBinder::DeathRecipient
         virtual void binderDied(const wp<IBinder>& who);

     private:
         sp<StreamSplitter> mSplitter;
         sp<IGraphicBufferProducer> mOutput;
     };

     class BufferTracker : public LightRefBase<BufferTracker> {
     public:
         BufferTracker(const sp<GraphicBuffer>& buffer);

         const sp<GraphicBuffer>& getBuffer() const { return mBuffer; }
         const sp<Fence>& getMergedFence() const { return mMergedFence; }

         void mergeFence(const sp<Fence>& with);

         // Returns the new value
         // Only called while mMutex is held
         size_t incrementReleaseCountLocked() { return ++mReleaseCount; }

     private:
         // Only destroy through LightRefBase
         friend LightRefBase<BufferTracker>;
         ~BufferTracker();

         // Disallow copying
         BufferTracker(const BufferTracker& other);
         BufferTracker& operator=(const BufferTracker& other);

         sp<GraphicBuffer> mBuffer; // One instance that holds this native handle
         sp<Fence> mMergedFence;
         size_t mReleaseCount;
     };

     // Only called from createSplitter
     StreamSplitter(const sp<IGraphicBufferConsumer>& inputQueue);

     // Must be accessed through RefBase
     virtual ~StreamSplitter();

     static const int MAX_OUTSTANDING_BUFFERS = 2;

     // mIsAbandoned is set to true when an output dies. Once the StreamSplitter
     // has been abandoned, it will continue to detach buffers from other
     // outputs, but it will disconnect from the input and not attempt to
     // communicate with it further.
     bool mIsAbandoned;

     Mutex mMutex;
     Condition mReleaseCondition;
     int mOutstandingBuffers;
     sp<IGraphicBufferConsumer> mInput;
     Vector<sp<IGraphicBufferProducer> > mOutputs;

     // Map of GraphicBuffer IDs (GraphicBuffer::getId()) to buffer tracking
     // objects (which are mostly for counting how many outputs have released the
     // buffer, but also contain merged release fences).
     KeyedVector<uint64_t, sp<BufferTracker> > mBuffers;
 };

 } // namespace android

 #endif
	/*
	* Copyright 2014 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#ifndef ANDROID_GUI_STREAMSPLITTER_H
	#define ANDROID_GUI_STREAMSPLITTER_H

	#include <gui/IConsumerListener.h>
	#include <gui/IProducerListener.h>

	#include <utils/Condition.h>
	#include <utils/KeyedVector.h>
	#include <utils/Mutex.h>
	#include <utils/StrongPointer.h>

	namespace android {

	class GraphicBuffer;
	class IGraphicBufferConsumer;
	class IGraphicBufferProducer;

	// StreamSplitter is an autonomous class that manages one input BufferQueue
	// and multiple output BufferQueues. By using the buffer attach and detach logic
	// in BufferQueue, it is able to present the illusion of a single split
	// BufferQueue, where each buffer queued to the input is available to be
	// acquired by each of the outputs, and is able to be dequeued by the input
	// again only once all of the outputs have released it.
	class StreamSplitter : public BnConsumerListener {
	public:
	// createSplitter creates a new splitter, outSplitter, using inputQueue as
	// the input BufferQueue. Output BufferQueues must be added using addOutput
	// before queueing any buffers to the input.
	//
	// A return value other than NO_ERROR means that an error has occurred and
	// outSplitter has not been modified. BAD_VALUE is returned if inputQueue or
	// outSplitter is NULL. See IGraphicBufferConsumer::consumerConnect for
	// explanations of other error codes.
	static status_t createSplitter(const sp<IGraphicBufferConsumer>& inputQueue,
	sp<StreamSplitter>* outSplitter);

	// addOutput adds an output BufferQueue to the splitter. The splitter
	// connects to outputQueue as a CPU producer, and any buffers queued
	// to the input will be queued to each output. It is assumed that all of the
	// outputs are added before any buffers are queued on the input. If any
	// output is abandoned by its consumer, the splitter will abandon its input
	// queue (see onAbandoned).
	//
	// A return value other than NO_ERROR means that an error has occurred and
	// outputQueue has not been added to the splitter. BAD_VALUE is returned if
	// outputQueue is NULL. See IGraphicBufferProducer::connect for explanations
	// of other error codes.
	status_t addOutput(const sp<IGraphicBufferProducer>& outputQueue);

	// setName sets the consumer name of the input queue
	void setName(const String8& name);

	private:
	// From IConsumerListener
	//
	// During this callback, we store some tracking information, detach the
	// buffer from the input, and attach it to each of the outputs. This call
	// can block if there are too many outstanding buffers. If it blocks, it
	// will resume when onBufferReleasedByOutput releases a buffer back to the
	// input.
	virtual void onFrameAvailable(const BufferItem& item);

	// From IConsumerListener
	// We don't care about released buffers because we detach each buffer as
	// soon as we acquire it. See the comment for onBufferReleased below for
	// some clarifying notes about the name.
	virtual void onBuffersReleased() {}

	// From IConsumerListener
	// We don't care about sideband streams, since we won't be splitting them
	virtual void onSidebandStreamChanged() {}

	// This is the implementation of the onBufferReleased callback from
	// IProducerListener. It gets called from an OutputListener (see below), and
	// 'from' is which producer interface from which the callback was received.
	//
	// During this callback, we detach the buffer from the output queue that
	// generated the callback, update our state tracking to see if this is the
	// last output releasing the buffer, and if so, release it to the input.
	// If we release the buffer to the input, we allow a blocked
	// onFrameAvailable call to proceed.
	void onBufferReleasedByOutput(const sp<IGraphicBufferProducer>& from);

	// When this is called, the splitter disconnects from (i.e., abandons) its
	// input queue and signals any waiting onFrameAvailable calls to wake up.
	// It still processes callbacks from other outputs, but only detaches their
	// buffers so they can continue operating until they run out of buffers to
	// acquire. This must be called with mMutex locked.
	void onAbandonedLocked();

	// This is a thin wrapper class that lets us determine which BufferQueue
	// the IProducerListener::onBufferReleased callback is associated with. We
	// create one of these per output BufferQueue, and then pass the producer
	// into onBufferReleasedByOutput above.
	class OutputListener : public BnProducerListener,
	public IBinder::DeathRecipient {
	public:
	OutputListener(const sp<StreamSplitter>& splitter,
	const sp<IGraphicBufferProducer>& output);
	virtual ~OutputListener();

	// From IProducerListener
	virtual void onBufferReleased();

	// From IBinder::DeathRecipient
	virtual void binderDied(const wp<IBinder>& who);

	private:
	sp<StreamSplitter> mSplitter;
	sp<IGraphicBufferProducer> mOutput;
	};

	class BufferTracker : public LightRefBase<BufferTracker> {
	public:
	BufferTracker(const sp<GraphicBuffer>& buffer);

	const sp<GraphicBuffer>& getBuffer() const { return mBuffer; }
	const sp<Fence>& getMergedFence() const { return mMergedFence; }

	void mergeFence(const sp<Fence>& with);

	// Returns the new value
	// Only called while mMutex is held
	size_t incrementReleaseCountLocked() { return ++mReleaseCount; }

	private:
	// Only destroy through LightRefBase
	friend LightRefBase<BufferTracker>;
	~BufferTracker();

	// Disallow copying
	BufferTracker(const BufferTracker& other);
	BufferTracker& operator=(const BufferTracker& other);

	sp<GraphicBuffer> mBuffer; // One instance that holds this native handle
	sp<Fence> mMergedFence;
	size_t mReleaseCount;
	};

	// Only called from createSplitter
	StreamSplitter(const sp<IGraphicBufferConsumer>& inputQueue);

	// Must be accessed through RefBase
	virtual ~StreamSplitter();

	static const int MAX_OUTSTANDING_BUFFERS = 2;

	// mIsAbandoned is set to true when an output dies. Once the StreamSplitter
	// has been abandoned, it will continue to detach buffers from other
	// outputs, but it will disconnect from the input and not attempt to
	// communicate with it further.
	bool mIsAbandoned;

	Mutex mMutex;
	Condition mReleaseCondition;
	int mOutstandingBuffers;
	sp<IGraphicBufferConsumer> mInput;
	Vector<sp<IGraphicBufferProducer> > mOutputs;

	// Map of GraphicBuffer IDs (GraphicBuffer::getId()) to buffer tracking
	// objects (which are mostly for counting how many outputs have released the
	// buffer, but also contain merged release fences).
	KeyedVector<uint64_t, sp<BufferTracker> > mBuffers;
	};

	} // namespace android

	#endif