/* * 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 #include #include #include #include #include #include #include #include namespace android { // ---------------------------------------------------------------------------- class BufferQueue : public BnGraphicBufferProducer { public: enum { MIN_UNDEQUEUED_BUFFERS = 2 }; enum { NUM_BUFFER_SLOTS = 32 }; enum { NO_CONNECTED_API = 0 }; enum { INVALID_BUFFER_SLOT = -1 }; enum { STALE_BUFFER_SLOT = 1, NO_BUFFER_AVAILABLE, 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 }; // ConsumerListener is the interface through which the BufferQueue notifies // the consumer of events that the consumer may wish to react to. Because // the consumer will generally have a mutex that is locked during calls from // the consumer to the BufferQueue, these calls from the BufferQueue to the // consumer *MUST* be called only when the BufferQueue mutex is NOT locked. struct ConsumerListener : public virtual RefBase { // onFrameAvailable is called from queueBuffer each time an additional // frame becomes available for consumption. This means that frames that // are queued while in asynchronous mode only trigger the callback if no // previous frames are pending. Frames queued while in synchronous mode // always trigger the callback. // // This is called without any lock held and can be called concurrently // by multiple threads. virtual void onFrameAvailable() = 0; // onBuffersReleased is called to notify the buffer consumer that the // BufferQueue has released its references to one or more GraphicBuffers // contained in its slots. The buffer consumer should then call // BufferQueue::getReleasedBuffers to retrieve the list of buffers // // This is called without any lock held and can be called concurrently // by multiple threads. virtual void onBuffersReleased() = 0; }; // 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 BufferQueue::ConsumerListener { public: ProxyConsumerListener(const wp& consumerListener); virtual ~ProxyConsumerListener(); virtual void onFrameAvailable(); virtual void onBuffersReleased(); private: // mConsumerListener is a weak reference to the ConsumerListener. This is // the raison d'etre of ProxyConsumerListener. wp mConsumerListener; }; // BufferQueue manages a pool of gralloc memory slots to be used by // producers and consumers. allowSynchronousMode specifies whether or not // synchronous mode can be enabled by the producer. allocator is used to // allocate all the needed gralloc buffers. BufferQueue(bool allowSynchronousMode = true, const sp& allocator = NULL); virtual ~BufferQueue(); // 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 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* 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, 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); // setSynchronousMode sets whether dequeueBuffer is synchronous or // asynchronous. In synchronous mode, dequeueBuffer blocks until // a buffer is available, the currently bound buffer can be dequeued and // queued buffers will be acquired in order. In asynchronous mode, // a queued buffer may be replaced by a subsequently queued buffer. // // The default mode is asynchronous. virtual status_t setSynchronousMode(bool enabled); // 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(int api, 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); // dump our state in a String virtual void dump(String8& result) const; virtual void dump(String8& result, const char* prefix) const; // public facing structure for BufferSlot struct BufferItem { BufferItem() : mTransform(0), mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), mTimestamp(0), mFrameNumber(0), mBuf(INVALID_BUFFER_SLOT), mAcquireCalled(false) { mCrop.makeInvalid(); } // mGraphicBuffer points to the buffer allocated for this slot, or is NULL // if the buffer in this slot has been acquired in the past (see // BufferSlot.mAcquireCalled). sp mGraphicBuffer; // mCrop is the current crop rectangle for this buffer slot. Rect mCrop; // mTransform is the current transform flags for this buffer slot. uint32_t mTransform; // mScalingMode is the current scaling mode for this buffer slot. uint32_t mScalingMode; // mTimestamp is the current timestamp for this buffer slot. This gets // to set by queueBuffer each time this slot is queued. int64_t mTimestamp; // mFrameNumber is the number of the queued frame for this slot. uint64_t mFrameNumber; // mBuf is the slot index of this buffer int mBuf; // mFence is a fence that will signal when the buffer is idle. sp mFence; // Indicates whether this buffer has been seen by a consumer yet bool mAcquireCalled; }; // The following public functions are the consumer-facing interface // acquireBuffer attempts to acquire ownership of the next pending buffer in // the BufferQueue. If no buffer is pending then it returns -EINVAL. 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. 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. status_t releaseBuffer(int buf, uint64_t frameNumber, EGLDisplay display, EGLSyncKHR fence, const sp& 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. // // consumer may not be NULL. status_t consumerConnect(const sp& consumer); // 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. 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. 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. 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. status_t setDefaultMaxBufferCount(int bufferCount); // 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. status_t setMaxAcquiredBufferCount(int maxAcquiredBuffers); // isSynchronousMode returns whether the BufferQueue is currently in // synchronous mode. bool isSynchronousMode() const; // setConsumerName sets the name used in logging 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. 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. 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). status_t setTransformHint(uint32_t hint); private: // freeBufferLocked frees the GraphicBuffer and sync resources for the // given slot. void freeBufferLocked(int index); // freeAllBuffersLocked frees the GraphicBuffer and sync resources for // all slots. void freeAllBuffersLocked(); // drainQueueLocked waits for the buffer queue to empty if we're in // synchronous mode, or returns immediately otherwise. It returns NO_INIT // if the BufferQueue is abandoned (consumer disconnected) or disconnected // (producer disconnected) during the call. status_t drainQueueLocked(); // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in // synchronous mode and free all buffers. In asynchronous mode, all buffers // are freed except the currently queued buffer (if it exists). status_t drainQueueAndFreeBuffersLocked(); // setDefaultMaxBufferCountLocked sets the maximum number of buffer slots // that will be used if the producer does not override the buffer slot // count. The count must be between 2 and NUM_BUFFER_SLOTS, inclusive. // The initial default is 2. status_t setDefaultMaxBufferCountLocked(int count); // getMinBufferCountLocked returns the minimum number of buffers allowed // given the current BufferQueue state. int getMinMaxBufferCountLocked() const; // getMinUndequeuedBufferCountLocked returns the minimum number of buffers // that must remain in a state other than DEQUEUED. int getMinUndequeuedBufferCountLocked() const; // getMaxBufferCountLocked returns the maximum number of buffers that can // be allocated at once. This value depends upon the following member // variables: // // mSynchronousMode // mMaxAcquiredBufferCount // mDefaultMaxBufferCount // mOverrideMaxBufferCount // // Any time one of these member variables is changed while a producer is // connected, mDequeueCondition must be broadcast. int getMaxBufferCountLocked() const; // stillTracking returns true iff the buffer item is still being tracked // in one of the slots. bool stillTracking(const BufferItem *item) const; struct BufferSlot { BufferSlot() : mEglDisplay(EGL_NO_DISPLAY), mBufferState(BufferSlot::FREE), mRequestBufferCalled(false), mFrameNumber(0), mEglFence(EGL_NO_SYNC_KHR), mAcquireCalled(false), mNeedsCleanupOnRelease(false) { } // mGraphicBuffer points to the buffer allocated for this slot or is NULL // if no buffer has been allocated. sp mGraphicBuffer; // mEglDisplay is the EGLDisplay used to create EGLSyncKHR objects. EGLDisplay mEglDisplay; // BufferState represents the different states in which a buffer slot // can be. All slots are initially FREE. enum BufferState { // FREE indicates that the buffer is available to be dequeued // by the producer. The buffer may be in use by the consumer for // a finite time, so the buffer must not be modified until the // associated fence is signaled. // // The slot is "owned" by BufferQueue. It transitions to DEQUEUED // when dequeueBuffer is called. FREE = 0, // DEQUEUED indicates that the buffer has been dequeued by the // producer, but has not yet been queued or canceled. The // producer may modify the buffer's contents as soon as the // associated ready fence is signaled. // // The slot is "owned" by the producer. It can transition to // QUEUED (via queueBuffer) or back to FREE (via cancelBuffer). DEQUEUED = 1, // QUEUED indicates that the buffer has been filled by the // producer and queued for use by the consumer. The buffer // contents may continue to be modified for a finite time, so // the contents must not be accessed until the associated fence // is signaled. // // The slot is "owned" by BufferQueue. It can transition to // ACQUIRED (via acquireBuffer) or to FREE (if another buffer is // queued in asynchronous mode). QUEUED = 2, // ACQUIRED indicates that the buffer has been acquired by the // consumer. As with QUEUED, the contents must not be accessed // by the consumer until the fence is signaled. // // The slot is "owned" by the consumer. It transitions to FREE // when releaseBuffer is called. ACQUIRED = 3 }; // mBufferState is the current state of this buffer slot. BufferState mBufferState; // mRequestBufferCalled is used for validating that the producer did // call requestBuffer() when told to do so. Technically this is not // needed but useful for debugging and catching producer bugs. bool mRequestBufferCalled; // mFrameNumber is the number of the queued frame for this slot. This // is used to dequeue buffers in LRU order (useful because buffers // may be released before their release fence is signaled). uint64_t mFrameNumber; // mEglFence is the EGL sync object that must signal before the buffer // associated with this buffer slot may be dequeued. It is initialized // to EGL_NO_SYNC_KHR when the buffer is created and may be set to a // new sync object in releaseBuffer. (This is deprecated in favor of // mFence, below.) EGLSyncKHR mEglFence; // mFence is a fence which will signal when work initiated by the // previous owner of the buffer is finished. When the buffer is FREE, // the fence indicates when the consumer has finished reading // from the buffer, or when the producer has finished writing if it // called cancelBuffer after queueing some writes. When the buffer is // QUEUED, it indicates when the producer has finished filling the // buffer. When the buffer is DEQUEUED or ACQUIRED, the fence has been // passed to the consumer or producer along with ownership of the // buffer, and mFence is set to NO_FENCE. sp mFence; // Indicates whether this buffer has been seen by a consumer yet bool mAcquireCalled; // Indicates whether this buffer needs to be cleaned up by the // consumer. This is set when a buffer in ACQUIRED state is freed. // It causes releaseBuffer to return STALE_BUFFER_SLOT. bool mNeedsCleanupOnRelease; }; // mSlots is the array of buffer slots that must be mirrored on the // producer side. This allows buffer ownership to be transferred between // the producer and consumer without sending a GraphicBuffer over binder. // The entire array is initialized to NULL at construction time, and // buffers are allocated for a slot when requestBuffer is called with // that slot's index. BufferSlot mSlots[NUM_BUFFER_SLOTS]; // mDefaultWidth holds the default width of allocated buffers. It is used // in dequeueBuffer() if a width and height of zero is specified. uint32_t mDefaultWidth; // mDefaultHeight holds the default height of allocated buffers. It is used // in dequeueBuffer() if a width and height of zero is specified. uint32_t mDefaultHeight; // mMaxAcquiredBufferCount is the number of buffers that the consumer may // acquire at one time. It defaults to 1 and can be changed by the // consumer via the setMaxAcquiredBufferCount method, but this may only be // done when no producer is connected to the BufferQueue. // // This value is used to derive the value returned for the // MIN_UNDEQUEUED_BUFFERS query by the producer. int mMaxAcquiredBufferCount; // mDefaultMaxBufferCount is the default limit on the number of buffers // that will be allocated at one time. This default limit is set by the // consumer. The limit (as opposed to the default limit) may be // overridden by the producer. int mDefaultMaxBufferCount; // mOverrideMaxBufferCount is the limit on the number of buffers that will // be allocated at one time. This value is set by the image producer by // calling setBufferCount. The default is zero, which means the producer // doesn't care about the number of buffers in the pool. In that case // mDefaultMaxBufferCount is used as the limit. int mOverrideMaxBufferCount; // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to // allocate new GraphicBuffer objects. sp mGraphicBufferAlloc; // mConsumerListener is used to notify the connected consumer of // asynchronous events that it may wish to react to. It is initially set // to NULL and is written by consumerConnect and consumerDisconnect. sp mConsumerListener; // mSynchronousMode whether we're in synchronous mode or not bool mSynchronousMode; // mAllowSynchronousMode whether we allow synchronous mode or not. Set // when the BufferQueue is created (by the consumer). const bool mAllowSynchronousMode; // mConnectedApi indicates the producer API that is currently connected // to this BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets // updated by the connect and disconnect methods. int mConnectedApi; // mDequeueCondition condition used for dequeueBuffer in synchronous mode mutable Condition mDequeueCondition; // mQueue is a FIFO of queued buffers used in synchronous mode typedef Vector Fifo; Fifo mQueue; // mAbandoned indicates that the BufferQueue will no longer be used to // consume image buffers pushed to it using the IGraphicBufferProducer // interface. It is initialized to false, and set to true in the // consumerDisconnect method. A BufferQueue that has been abandoned will // return the NO_INIT error from all IGraphicBufferProducer methods // capable of returning an error. bool mAbandoned; // mConsumerName is a string used to identify the BufferQueue in log // messages. It is set by the setConsumerName method. String8 mConsumerName; // mMutex is the mutex used to prevent concurrent access to the member // variables of BufferQueue objects. It must be locked whenever the // member variables are accessed. mutable Mutex mMutex; // mFrameCounter is the free running counter, incremented on every // successful queueBuffer call, and buffer allocation. uint64_t mFrameCounter; // mBufferHasBeenQueued is true once a buffer has been queued. It is // reset when something causes all buffers to be freed (e.g. changing the // buffer count). bool mBufferHasBeenQueued; // mDefaultBufferFormat can be set so it will override // the buffer format when it isn't specified in dequeueBuffer uint32_t mDefaultBufferFormat; // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers uint32_t mConsumerUsageBits; // mTransformHint is used to optimize for screen rotations uint32_t mTransformHint; }; // ---------------------------------------------------------------------------- }; // namespace android #endif // ANDROID_GUI_BUFFERQUEUE_H