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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/BufferQueueDefs.h>
#include <gui/IGraphicBufferProducer.h>
namespace android {
class BufferSlot;
class BufferQueueProducer : public BnGraphicBufferProducer,
private IBinder::DeathRecipient {
friend class BufferQueue; // Needed to access binderDied
BufferQueueProducer(const sp<BufferQueueCore>& core);
virtual ~BufferQueueProducer();
// 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// flags indicating that previously-returned buffers are no longer valid.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);
// 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);
// 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 outFence 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
// 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.
// 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 *outSlot, sp<Fence>* outFence,
bool async, uint32_t width, uint32_t height, PixelFormat format,
uint32_t usage);
// See IGraphicBufferProducer::detachBuffer
virtual status_t detachBuffer(int slot);
// See IGraphicBufferProducer::detachNextBuffer
virtual status_t detachNextBuffer(sp<GraphicBuffer>* outBuffer,
sp<Fence>* outFence);
// See IGraphicBufferProducer::attachBuffer
virtual status_t attachBuffer(int* outSlot, const sp<GraphicBuffer>& buffer);
// 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 slot,
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 slot, const sp<Fence>& fence);
// Query native window attributes. The "what" values are enumerated in
// window.h (e.g. NATIVE_WINDOW_FORMAT).
virtual int query(int what, int* outValue);
// 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<IProducerListener>& listener,
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 IGraphicBufferProducer.
// 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);
// See IGraphicBufferProducer::allocateBuffers
virtual void allocateBuffers(bool async, uint32_t width, uint32_t height,
PixelFormat format, uint32_t usage);
// See IGraphicBufferProducer::allowAllocation
virtual status_t allowAllocation(bool allow);
// See IGraphicBufferProducer::setGenerationNumber
virtual status_t setGenerationNumber(uint32_t generationNumber);
// See IGraphicBufferProducer::getConsumerName
virtual String8 getConsumerName() const override;
// This is required by the IBinder::DeathRecipient interface
virtual void binderDied(const wp<IBinder>& who);
// waitForFreeSlotThenRelock finds the oldest slot in the FREE state. It may
// block if there are no available slots and we are not in non-blocking
// mode (producer and consumer controlled by the application). If it blocks,
// it will release mCore->mMutex while blocked so that other operations on
// the BufferQueue may succeed.
status_t waitForFreeSlotThenRelock(const char* caller, bool async,
int* found, status_t* returnFlags) const;
sp<BufferQueueCore> mCore;
// This references mCore->mSlots. Lock mCore->mMutex while accessing.
BufferQueueDefs::SlotsType& mSlots;
// This is a cached copy of the name stored in the BufferQueueCore.
// It's updated during connect and dequeueBuffer (which should catch
// most updates).
String8 mConsumerName;
uint32_t mStickyTransform;
// This saves the fence from the last queueBuffer, such that the
// next queueBuffer call can throttle buffer production. The prior
// queueBuffer's fence is not nessessarily available elsewhere,
// since the previous buffer might have already been acquired.
sp<Fence> mLastQueueBufferFence;
// Take-a-ticket system for ensuring that onFrame* callbacks are called in
// the order that frames are queued. While the BufferQueue lock
// (mCore->mMutex) is held, a ticket is retained by the producer. After
// dropping the BufferQueue lock, the producer must wait on the condition
// variable until the current callback ticket matches its retained ticket.
Mutex mCallbackMutex;
int mNextCallbackTicket; // Protected by mCore->mMutex
int mCurrentCallbackTicket; // Protected by mCallbackMutex
Condition mCallbackCondition;
}; // class BufferQueueProducer
} // namespace android