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* 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
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#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 {
// 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);
// 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 {
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);
sp<StreamSplitter> mSplitter;
sp<IGraphicBufferProducer> mOutput;
class BufferTracker : public LightRefBase<BufferTracker> {
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; }
// Only destroy through LightRefBase
friend LightRefBase<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