include/gui/BufferQueue.h - LeafOS-Project/android_frameworks_native - Gitiles

 /*
  * Copyright (C) 2012 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_BUFFERQUEUE_H
 #define ANDROID_GUI_BUFFERQUEUE_H

 #include <gui/BufferQueueProducer.h>
 #include <gui/BufferQueueConsumer.h>
 #include <gui/IConsumerListener.h>

 // These are only required to keep other parts of the framework with incomplete
 // dependencies building successfully
 #include <gui/IGraphicBufferAlloc.h>

 #include <binder/IBinder.h>

 namespace android {
 // ----------------------------------------------------------------------------

 class BufferQueue : public BnGraphicBufferProducer,
                     public BnGraphicBufferConsumer,
                     private IBinder::DeathRecipient {
 public:
     // BufferQueue will keep track of at most this value of buffers.
     // Attempts at runtime to increase the number of buffers past this will fail.
     enum { NUM_BUFFER_SLOTS = 32 };
     // Used as a placeholder slot# when the value isn't pointing to an existing buffer.
     enum { INVALID_BUFFER_SLOT = IGraphicBufferConsumer::BufferItem::INVALID_BUFFER_SLOT };
     // Alias to <IGraphicBufferConsumer.h> -- please scope from there in future code!
     enum {
         NO_BUFFER_AVAILABLE = IGraphicBufferConsumer::NO_BUFFER_AVAILABLE,
         PRESENT_LATER = IGraphicBufferConsumer::PRESENT_LATER,
     };

     // When in async mode we reserve two slots in order to guarantee that the
     // producer and consumer can run asynchronously.
     enum { MAX_MAX_ACQUIRED_BUFFERS = NUM_BUFFER_SLOTS - 2 };

     // for backward source compatibility
     typedef ::android::ConsumerListener ConsumerListener;

     // ProxyConsumerListener is a ConsumerListener implementation that keeps a weak
     // reference to the actual consumer object.  It forwards all calls to that
     // consumer object so long as it exists.
     //
     // This class exists to avoid having a circular reference between the
     // BufferQueue object and the consumer object.  The reason this can't be a weak
     // reference in the BufferQueue class is because we're planning to expose the
     // consumer side of a BufferQueue as a binder interface, which doesn't support
     // weak references.
     class ProxyConsumerListener : public BnConsumerListener {
     public:
         ProxyConsumerListener(const wp<ConsumerListener>& consumerListener);
         virtual ~ProxyConsumerListener();
         virtual void onFrameAvailable();
         virtual void onBuffersReleased();
         virtual void onSidebandStreamChanged();
     private:
         // mConsumerListener is a weak reference to the IConsumerListener.  This is
         // the raison d'etre of ProxyConsumerListener.
         wp<ConsumerListener> mConsumerListener;
     };

     // BufferQueue manages a pool of gralloc memory slots to be used by
     // producers and consumers. allocator is used to allocate all the
     // needed gralloc buffers.
     BufferQueue(const sp<IGraphicBufferAlloc>& allocator = NULL);
     virtual ~BufferQueue();

     /*
      * IBinder::DeathRecipient interface
      */

     virtual void binderDied(const wp<IBinder>& who);

     /*
      * IGraphicBufferProducer interface
      */

     // Query native window attributes.  The "what" values are enumerated in
     // window.h (e.g. NATIVE_WINDOW_FORMAT).
     virtual int query(int what, int* value);

     // setBufferCount updates the number of available buffer slots.  If this
     // method succeeds, buffer slots will be both unallocated and owned by
     // the BufferQueue object (i.e. they are not owned by the producer or
     // consumer).
     //
     // This will fail if the producer has dequeued any buffers, or if
     // bufferCount is invalid.  bufferCount must generally be a value
     // between the minimum undequeued buffer count (exclusive) and NUM_BUFFER_SLOTS
     // (inclusive).  It may also be set to zero (the default) to indicate
     // that the producer does not wish to set a value.  The minimum value
     // can be obtained by calling query(NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS,
     // ...).
     //
     // This may only be called by the producer.  The consumer will be told
     // to discard buffers through the onBuffersReleased callback.
     virtual status_t setBufferCount(int bufferCount);

     // requestBuffer returns the GraphicBuffer for slot N.
     //
     // In normal operation, this is called the first time slot N is returned
     // by dequeueBuffer.  It must be called again if dequeueBuffer returns
     // flags indicating that previously-returned buffers are no longer valid.
     virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf);

     // dequeueBuffer gets the next buffer slot index for the producer to use.
     // If a buffer slot is available then that slot index is written to the
     // location pointed to by the buf argument and a status of OK is returned.
     // If no slot is available then a status of -EBUSY is returned and buf is
     // unmodified.
     //
     // The fence parameter will be updated to hold the fence associated with
     // the buffer. The contents of the buffer must not be overwritten until the
     // fence signals. If the fence is Fence::NO_FENCE, the buffer may be
     // written immediately.
     //
     // The width and height parameters must be no greater than the minimum of
     // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
     // An error due to invalid dimensions might not be reported until
     // updateTexImage() is called.  If width and height are both zero, the
     // default values specified by setDefaultBufferSize() are used instead.
     //
     // The pixel formats are enumerated in graphics.h, e.g.
     // HAL_PIXEL_FORMAT_RGBA_8888.  If the format is 0, the default format
     // will be used.
     //
     // The usage argument specifies gralloc buffer usage flags.  The values
     // are enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER.  These
     // will be merged with the usage flags specified by setConsumerUsageBits.
     //
     // The return value may be a negative error value or a non-negative
     // collection of flags.  If the flags are set, the return values are
     // valid, but additional actions must be performed.
     //
     // If IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION is set, the
     // producer must discard cached GraphicBuffer references for the slot
     // returned in buf.
     // If IGraphicBufferProducer::RELEASE_ALL_BUFFERS is set, the producer
     // must discard cached GraphicBuffer references for all slots.
     //
     // In both cases, the producer will need to call requestBuffer to get a
     // GraphicBuffer handle for the returned slot.
     virtual status_t dequeueBuffer(int *buf, sp<Fence>* fence, bool async,
             uint32_t width, uint32_t height, uint32_t format, uint32_t usage);

     // queueBuffer returns a filled buffer to the BufferQueue.
     //
     // Additional data is provided in the QueueBufferInput struct.  Notably,
     // a timestamp must be provided for the buffer. The timestamp is in
     // nanoseconds, and must be monotonically increasing. Its other semantics
     // (zero point, etc) are producer-specific and should be documented by the
     // producer.
     //
     // The caller may provide a fence that signals when all rendering
     // operations have completed.  Alternatively, NO_FENCE may be used,
     // indicating that the buffer is ready immediately.
     //
     // Some values are returned in the output struct: the current settings
     // for default width and height, the current transform hint, and the
     // number of queued buffers.
     virtual status_t queueBuffer(int buf,
             const QueueBufferInput& input, QueueBufferOutput* output);

     // cancelBuffer returns a dequeued buffer to the BufferQueue, but doesn't
     // queue it for use by the consumer.
     //
     // The buffer will not be overwritten until the fence signals.  The fence
     // will usually be the one obtained from dequeueBuffer.
     virtual void cancelBuffer(int buf, const sp<Fence>& fence);

     // connect attempts to connect a producer API to the BufferQueue.  This
     // must be called before any other IGraphicBufferProducer methods are
     // called except for getAllocator.  A consumer must already be connected.
     //
     // This method will fail if connect was previously called on the
     // BufferQueue and no corresponding disconnect call was made (i.e. if
     // it's still connected to a producer).
     //
     // APIs are enumerated in window.h (e.g. NATIVE_WINDOW_API_CPU).
     virtual status_t connect(const sp<IBinder>& token,
             int api, bool producerControlledByApp, QueueBufferOutput* output);

     // disconnect attempts to disconnect a producer API from the BufferQueue.
     // Calling this method will cause any subsequent calls to other
     // IGraphicBufferProducer methods to fail except for getAllocator and connect.
     // Successfully calling connect after this will allow the other methods to
     // succeed again.
     //
     // This method will fail if the the BufferQueue is not currently
     // connected to the specified producer API.
     virtual status_t disconnect(int api);

     // Attaches a sideband buffer stream to the BufferQueue.
     //
     // A sideband stream is a device-specific mechanism for passing buffers
     // from the producer to the consumer without using dequeueBuffer/
     // queueBuffer. If a sideband stream is present, the consumer can choose
     // whether to acquire buffers from the sideband stream or from the queued
     // buffers.
     //
     // Passing NULL or a different stream handle will detach the previous
     // handle if any.
     virtual status_t setSidebandStream(const sp<NativeHandle>& stream);

     /*
      * IGraphicBufferConsumer interface
      */

     // acquireBuffer attempts to acquire ownership of the next pending buffer in
     // the BufferQueue.  If no buffer is pending then it returns NO_BUFFER_AVAILABLE. If a
     // buffer is successfully acquired, the information about the buffer is
     // returned in BufferItem.  If the buffer returned had previously been
     // acquired then the BufferItem::mGraphicBuffer field of buffer is set to
     // NULL and it is assumed that the consumer still holds a reference to the
     // buffer.
     //
     // If presentWhen is nonzero, it indicates the time when the buffer will
     // be displayed on screen.  If the buffer's timestamp is farther in the
     // future, the buffer won't be acquired, and PRESENT_LATER will be
     // returned.  The presentation time is in nanoseconds, and the time base
     // is CLOCK_MONOTONIC.
     virtual status_t acquireBuffer(BufferItem* buffer, nsecs_t presentWhen);

     // releaseBuffer releases a buffer slot from the consumer back to the
     // BufferQueue.  This may be done while the buffer's contents are still
     // being accessed.  The fence will signal when the buffer is no longer
     // in use. frameNumber is used to indentify the exact buffer returned.
     //
     // If releaseBuffer returns STALE_BUFFER_SLOT, then the consumer must free
     // any references to the just-released buffer that it might have, as if it
     // had received a onBuffersReleased() call with a mask set for the released
     // buffer.
     //
     // Note that the dependencies on EGL will be removed once we switch to using
     // the Android HW Sync HAL.
     virtual status_t releaseBuffer(int buf, uint64_t frameNumber,
             EGLDisplay display, EGLSyncKHR fence,
             const sp<Fence>& releaseFence);

     // consumerConnect connects a consumer to the BufferQueue.  Only one
     // consumer may be connected, and when that consumer disconnects the
     // BufferQueue is placed into the "abandoned" state, causing most
     // interactions with the BufferQueue by the producer to fail.
     // controlledByApp indicates whether the consumer is controlled by
     // the application.
     //
     // consumer may not be NULL.
     virtual status_t consumerConnect(const sp<IConsumerListener>& consumer, bool controlledByApp);

     // consumerDisconnect disconnects a consumer from the BufferQueue. All
     // buffers will be freed and the BufferQueue is placed in the "abandoned"
     // state, causing most interactions with the BufferQueue by the producer to
     // fail.
     virtual status_t consumerDisconnect();

     // getReleasedBuffers sets the value pointed to by slotMask to a bit mask
     // indicating which buffer slots have been released by the BufferQueue
     // but have not yet been released by the consumer.
     //
     // This should be called from the onBuffersReleased() callback.
     virtual status_t getReleasedBuffers(uint32_t* slotMask);

     // setDefaultBufferSize is used to set the size of buffers returned by
     // dequeueBuffer when a width and height of zero is requested.  Default
     // is 1x1.
     virtual status_t setDefaultBufferSize(uint32_t w, uint32_t h);

     // setDefaultMaxBufferCount sets the default value for the maximum buffer
     // count (the initial default is 2). If the producer has requested a
     // buffer count using setBufferCount, the default buffer count will only
     // take effect if the producer sets the count back to zero.
     //
     // The count must be between 2 and NUM_BUFFER_SLOTS, inclusive.
     virtual status_t setDefaultMaxBufferCount(int bufferCount);

     // disableAsyncBuffer disables the extra buffer used in async mode
     // (when both producer and consumer have set their "isControlledByApp"
     // flag) and has dequeueBuffer() return WOULD_BLOCK instead.
     //
     // This can only be called before consumerConnect().
     virtual status_t disableAsyncBuffer();

     // setMaxAcquiredBufferCount sets the maximum number of buffers that can
     // be acquired by the consumer at one time (default 1).  This call will
     // fail if a producer is connected to the BufferQueue.
     virtual status_t setMaxAcquiredBufferCount(int maxAcquiredBuffers);

     // setConsumerName sets the name used in logging
     virtual void setConsumerName(const String8& name);

     // setDefaultBufferFormat allows the BufferQueue to create
     // GraphicBuffers of a defaultFormat if no format is specified
     // in dequeueBuffer.  Formats are enumerated in graphics.h; the
     // initial default is HAL_PIXEL_FORMAT_RGBA_8888.
     virtual status_t setDefaultBufferFormat(uint32_t defaultFormat);

     // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer.
     // These are merged with the bits passed to dequeueBuffer.  The values are
     // enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER; the default is 0.
     virtual status_t setConsumerUsageBits(uint32_t usage);

     // setTransformHint bakes in rotation to buffers so overlays can be used.
     // The values are enumerated in window.h, e.g.
     // NATIVE_WINDOW_TRANSFORM_ROT_90.  The default is 0 (no transform).
     virtual status_t setTransformHint(uint32_t hint);

     // Retrieve the BufferQueue's sideband stream, if any.
     virtual sp<NativeHandle> getSidebandStream() const;

     // dump our state in a String
     virtual void dump(String8& result, const char* prefix) const;

 private:
     sp<BufferQueueProducer> mProducer;
     sp<BufferQueueConsumer> mConsumer;
 };

 // ----------------------------------------------------------------------------
 }; // namespace android

 #endif // ANDROID_GUI_BUFFERQUEUE_H
	/*
	* Copyright (C) 2012 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_BUFFERQUEUE_H
	#define ANDROID_GUI_BUFFERQUEUE_H

	#include <gui/BufferQueueProducer.h>
	#include <gui/BufferQueueConsumer.h>
	#include <gui/IConsumerListener.h>

	// These are only required to keep other parts of the framework with incomplete
	// dependencies building successfully
	#include <gui/IGraphicBufferAlloc.h>

	#include <binder/IBinder.h>

	namespace android {
	// ----------------------------------------------------------------------------

	class BufferQueue : public BnGraphicBufferProducer,
	public BnGraphicBufferConsumer,
	private IBinder::DeathRecipient {
	public:
	// BufferQueue will keep track of at most this value of buffers.
	// Attempts at runtime to increase the number of buffers past this will fail.
	enum { NUM_BUFFER_SLOTS = 32 };
	// Used as a placeholder slot# when the value isn't pointing to an existing buffer.
	enum { INVALID_BUFFER_SLOT = IGraphicBufferConsumer::BufferItem::INVALID_BUFFER_SLOT };
	// Alias to <IGraphicBufferConsumer.h> -- please scope from there in future code!
	enum {
	NO_BUFFER_AVAILABLE = IGraphicBufferConsumer::NO_BUFFER_AVAILABLE,
	PRESENT_LATER = IGraphicBufferConsumer::PRESENT_LATER,
	};

	// When in async mode we reserve two slots in order to guarantee that the
	// producer and consumer can run asynchronously.
	enum { MAX_MAX_ACQUIRED_BUFFERS = NUM_BUFFER_SLOTS - 2 };

	// for backward source compatibility
	typedef ::android::ConsumerListener ConsumerListener;

	// ProxyConsumerListener is a ConsumerListener implementation that keeps a weak
	// reference to the actual consumer object. It forwards all calls to that
	// consumer object so long as it exists.
	//
	// This class exists to avoid having a circular reference between the
	// BufferQueue object and the consumer object. The reason this can't be a weak
	// reference in the BufferQueue class is because we're planning to expose the
	// consumer side of a BufferQueue as a binder interface, which doesn't support
	// weak references.
	class ProxyConsumerListener : public BnConsumerListener {
	public:
	ProxyConsumerListener(const wp<ConsumerListener>& consumerListener);
	virtual ~ProxyConsumerListener();
	virtual void onFrameAvailable();
	virtual void onBuffersReleased();
	virtual void onSidebandStreamChanged();
	private:
	// mConsumerListener is a weak reference to the IConsumerListener. This is
	// the raison d'etre of ProxyConsumerListener.
	wp<ConsumerListener> mConsumerListener;
	};

	// BufferQueue manages a pool of gralloc memory slots to be used by
	// producers and consumers. allocator is used to allocate all the
	// needed gralloc buffers.
	BufferQueue(const sp<IGraphicBufferAlloc>& allocator = NULL);
	virtual ~BufferQueue();

	/*
	* IBinder::DeathRecipient interface
	*/

	virtual void binderDied(const wp<IBinder>& who);

	/*
	* IGraphicBufferProducer interface
	*/

	// Query native window attributes. The "what" values are enumerated in
	// window.h (e.g. NATIVE_WINDOW_FORMAT).
	virtual int query(int what, int* value);

	// setBufferCount updates the number of available buffer slots. If this
	// method succeeds, buffer slots will be both unallocated and owned by
	// the BufferQueue object (i.e. they are not owned by the producer or
	// consumer).
	//
	// This will fail if the producer has dequeued any buffers, or if
	// bufferCount is invalid. bufferCount must generally be a value
	// between the minimum undequeued buffer count (exclusive) and NUM_BUFFER_SLOTS
	// (inclusive). It may also be set to zero (the default) to indicate
	// that the producer does not wish to set a value. The minimum value
	// can be obtained by calling query(NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS,
	// ...).
	//
	// This may only be called by the producer. The consumer will be told
	// to discard buffers through the onBuffersReleased callback.
	virtual status_t setBufferCount(int bufferCount);

	// requestBuffer returns the GraphicBuffer for slot N.
	//
	// In normal operation, this is called the first time slot N is returned
	// by dequeueBuffer. It must be called again if dequeueBuffer returns
	// flags indicating that previously-returned buffers are no longer valid.
	virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf);

	// dequeueBuffer gets the next buffer slot index for the producer to use.
	// If a buffer slot is available then that slot index is written to the
	// location pointed to by the buf argument and a status of OK is returned.
	// If no slot is available then a status of -EBUSY is returned and buf is
	// unmodified.
	//
	// The fence parameter will be updated to hold the fence associated with
	// the buffer. The contents of the buffer must not be overwritten until the
	// fence signals. If the fence is Fence::NO_FENCE, the buffer may be
	// written immediately.
	//
	// The width and height parameters must be no greater than the minimum of
	// GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
	// An error due to invalid dimensions might not be reported until
	// updateTexImage() is called. If width and height are both zero, the
	// default values specified by setDefaultBufferSize() are used instead.
	//
	// The pixel formats are enumerated in graphics.h, e.g.
	// HAL_PIXEL_FORMAT_RGBA_8888. If the format is 0, the default format
	// will be used.
	//
	// The usage argument specifies gralloc buffer usage flags. The values
	// are enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER. These
	// will be merged with the usage flags specified by setConsumerUsageBits.
	//
	// The return value may be a negative error value or a non-negative
	// collection of flags. If the flags are set, the return values are
	// valid, but additional actions must be performed.
	//
	// If IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION is set, the
	// producer must discard cached GraphicBuffer references for the slot
	// returned in buf.
	// If IGraphicBufferProducer::RELEASE_ALL_BUFFERS is set, the producer
	// must discard cached GraphicBuffer references for all slots.
	//
	// In both cases, the producer will need to call requestBuffer to get a
	// GraphicBuffer handle for the returned slot.
	virtual status_t dequeueBuffer(int buf, sp<Fence> fence, bool async,
	uint32_t width, uint32_t height, uint32_t format, uint32_t usage);

	// queueBuffer returns a filled buffer to the BufferQueue.
	//
	// Additional data is provided in the QueueBufferInput struct. Notably,
	// a timestamp must be provided for the buffer. The timestamp is in
	// nanoseconds, and must be monotonically increasing. Its other semantics
	// (zero point, etc) are producer-specific and should be documented by the
	// producer.
	//
	// The caller may provide a fence that signals when all rendering
	// operations have completed. Alternatively, NO_FENCE may be used,
	// indicating that the buffer is ready immediately.
	//
	// Some values are returned in the output struct: the current settings
	// for default width and height, the current transform hint, and the
	// number of queued buffers.
	virtual status_t queueBuffer(int buf,
	const QueueBufferInput& input, QueueBufferOutput* output);

	// cancelBuffer returns a dequeued buffer to the BufferQueue, but doesn't
	// queue it for use by the consumer.
	//
	// The buffer will not be overwritten until the fence signals. The fence
	// will usually be the one obtained from dequeueBuffer.
	virtual void cancelBuffer(int buf, const sp<Fence>& fence);

	// connect attempts to connect a producer API to the BufferQueue. This
	// must be called before any other IGraphicBufferProducer methods are
	// called except for getAllocator. A consumer must already be connected.
	//
	// This method will fail if connect was previously called on the
	// BufferQueue and no corresponding disconnect call was made (i.e. if
	// it's still connected to a producer).
	//
	// APIs are enumerated in window.h (e.g. NATIVE_WINDOW_API_CPU).
	virtual status_t connect(const sp<IBinder>& token,
	int api, bool producerControlledByApp, QueueBufferOutput* output);

	// disconnect attempts to disconnect a producer API from the BufferQueue.
	// Calling this method will cause any subsequent calls to other
	// IGraphicBufferProducer methods to fail except for getAllocator and connect.
	// Successfully calling connect after this will allow the other methods to
	// succeed again.
	//
	// This method will fail if the the BufferQueue is not currently
	// connected to the specified producer API.
	virtual status_t disconnect(int api);

	// Attaches a sideband buffer stream to the BufferQueue.
	//
	// A sideband stream is a device-specific mechanism for passing buffers
	// from the producer to the consumer without using dequeueBuffer/
	// queueBuffer. If a sideband stream is present, the consumer can choose
	// whether to acquire buffers from the sideband stream or from the queued
	// buffers.
	//
	// Passing NULL or a different stream handle will detach the previous
	// handle if any.
	virtual status_t setSidebandStream(const sp<NativeHandle>& stream);

	/*
	* IGraphicBufferConsumer interface
	*/

	// acquireBuffer attempts to acquire ownership of the next pending buffer in
	// the BufferQueue. If no buffer is pending then it returns NO_BUFFER_AVAILABLE. If a
	// buffer is successfully acquired, the information about the buffer is
	// returned in BufferItem. If the buffer returned had previously been
	// acquired then the BufferItem::mGraphicBuffer field of buffer is set to
	// NULL and it is assumed that the consumer still holds a reference to the
	// buffer.
	//
	// If presentWhen is nonzero, it indicates the time when the buffer will
	// be displayed on screen. If the buffer's timestamp is farther in the
	// future, the buffer won't be acquired, and PRESENT_LATER will be
	// returned. The presentation time is in nanoseconds, and the time base
	// is CLOCK_MONOTONIC.
	virtual status_t acquireBuffer(BufferItem* buffer, nsecs_t presentWhen);

	// releaseBuffer releases a buffer slot from the consumer back to the
	// BufferQueue. This may be done while the buffer's contents are still
	// being accessed. The fence will signal when the buffer is no longer
	// in use. frameNumber is used to indentify the exact buffer returned.
	//
	// If releaseBuffer returns STALE_BUFFER_SLOT, then the consumer must free
	// any references to the just-released buffer that it might have, as if it
	// had received a onBuffersReleased() call with a mask set for the released
	// buffer.
	//
	// Note that the dependencies on EGL will be removed once we switch to using
	// the Android HW Sync HAL.
	virtual status_t releaseBuffer(int buf, uint64_t frameNumber,
	EGLDisplay display, EGLSyncKHR fence,
	const sp<Fence>& releaseFence);

	// consumerConnect connects a consumer to the BufferQueue. Only one
	// consumer may be connected, and when that consumer disconnects the
	// BufferQueue is placed into the "abandoned" state, causing most
	// interactions with the BufferQueue by the producer to fail.
	// controlledByApp indicates whether the consumer is controlled by
	// the application.
	//
	// consumer may not be NULL.
	virtual status_t consumerConnect(const sp<IConsumerListener>& consumer, bool controlledByApp);

	// consumerDisconnect disconnects a consumer from the BufferQueue. All
	// buffers will be freed and the BufferQueue is placed in the "abandoned"
	// state, causing most interactions with the BufferQueue by the producer to
	// fail.
	virtual status_t consumerDisconnect();

	// getReleasedBuffers sets the value pointed to by slotMask to a bit mask
	// indicating which buffer slots have been released by the BufferQueue
	// but have not yet been released by the consumer.
	//
	// This should be called from the onBuffersReleased() callback.
	virtual status_t getReleasedBuffers(uint32_t* slotMask);

	// setDefaultBufferSize is used to set the size of buffers returned by
	// dequeueBuffer when a width and height of zero is requested. Default
	// is 1x1.
	virtual status_t setDefaultBufferSize(uint32_t w, uint32_t h);

	// setDefaultMaxBufferCount sets the default value for the maximum buffer
	// count (the initial default is 2). If the producer has requested a
	// buffer count using setBufferCount, the default buffer count will only
	// take effect if the producer sets the count back to zero.
	//
	// The count must be between 2 and NUM_BUFFER_SLOTS, inclusive.
	virtual status_t setDefaultMaxBufferCount(int bufferCount);

	// disableAsyncBuffer disables the extra buffer used in async mode
	// (when both producer and consumer have set their "isControlledByApp"
	// flag) and has dequeueBuffer() return WOULD_BLOCK instead.
	//
	// This can only be called before consumerConnect().
	virtual status_t disableAsyncBuffer();

	// setMaxAcquiredBufferCount sets the maximum number of buffers that can
	// be acquired by the consumer at one time (default 1). This call will
	// fail if a producer is connected to the BufferQueue.
	virtual status_t setMaxAcquiredBufferCount(int maxAcquiredBuffers);

	// setConsumerName sets the name used in logging
	virtual void setConsumerName(const String8& name);

	// setDefaultBufferFormat allows the BufferQueue to create
	// GraphicBuffers of a defaultFormat if no format is specified
	// in dequeueBuffer. Formats are enumerated in graphics.h; the
	// initial default is HAL_PIXEL_FORMAT_RGBA_8888.
	virtual status_t setDefaultBufferFormat(uint32_t defaultFormat);

	// setConsumerUsageBits will turn on additional usage bits for dequeueBuffer.
	// These are merged with the bits passed to dequeueBuffer. The values are
	// enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER; the default is 0.
	virtual status_t setConsumerUsageBits(uint32_t usage);

	// setTransformHint bakes in rotation to buffers so overlays can be used.
	// The values are enumerated in window.h, e.g.
	// NATIVE_WINDOW_TRANSFORM_ROT_90. The default is 0 (no transform).
	virtual status_t setTransformHint(uint32_t hint);

	// Retrieve the BufferQueue's sideband stream, if any.
	virtual sp<NativeHandle> getSidebandStream() const;

	// dump our state in a String
	virtual void dump(String8& result, const char* prefix) const;

	private:
	sp<BufferQueueProducer> mProducer;
	sp<BufferQueueConsumer> mConsumer;
	};

	// ----------------------------------------------------------------------------
	}; // namespace android

	#endif // ANDROID_GUI_BUFFERQUEUE_H