/* * 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 <EGL/egl.h> #include <EGL/eglext.h> #include <gui/IGraphicBufferAlloc.h> #include <gui/ISurfaceTexture.h> #include <ui/Fence.h> #include <ui/GraphicBuffer.h> #include <utils/String8.h> #include <utils/Vector.h> #include <utils/threads.h> namespace android { // ---------------------------------------------------------------------------- class BufferQueue : public BnSurfaceTexture { 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 }; // 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 // teh 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<BufferQueue::ConsumerListener>& 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<BufferQueue::ConsumerListener> 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<IGraphicBufferAlloc>& allocator = NULL); virtual ~BufferQueue(); virtual int query(int what, int* value); // setBufferCount updates the number of available buffer slots. After // calling this all buffer slots are both unallocated and owned by the // BufferQueue object (i.e. they are not owned by the client). virtual status_t setBufferCount(int bufferCount); virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf); // dequeueBuffer gets the next buffer slot index for the client 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 NULL, 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. virtual status_t dequeueBuffer(int *buf, sp<Fence>& fence, uint32_t width, uint32_t height, uint32_t format, uint32_t usage); // queueBuffer returns a filled buffer to the BufferQueue. In addition, 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 client-dependent and should be documented by the // client. virtual status_t queueBuffer(int buf, const QueueBufferInput& input, QueueBufferOutput* output); virtual void cancelBuffer(int buf, sp<Fence> fence); // setSynchronousMode set 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 retired in order. // The default mode is asynchronous. virtual status_t setSynchronousMode(bool enabled); // connect attempts to connect a producer client API to the BufferQueue. // This must be called before any other ISurfaceTexture methods are called // except for getAllocator. // // This method will fail if the connect was previously called on the // BufferQueue and no corresponding disconnect call was made. virtual status_t connect(int api, QueueBufferOutput* output); // disconnect attempts to disconnect a producer client API from the // BufferQueue. Calling this method will cause any subsequent calls to other // ISurfaceTexture 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 client 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, char* buffer, size_t SIZE) 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) { mCrop.makeInvalid(); } // mGraphicBuffer points to the buffer allocated for this slot or is NULL // if no buffer has been allocated. sp<GraphicBuffer> 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<Fence> mFence; }; // The following public functions is 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. status_t acquireBuffer(BufferItem *buffer); // releaseBuffer releases a buffer slot from the consumer back to the // BufferQueue pending a fence sync. // // 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, 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. status_t consumerConnect(const sp<ConsumerListener>& 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 the have been released by the BufferQueue // but have not yet been released by the consumer. status_t getReleasedBuffers(uint32_t* slotMask); // setDefaultBufferSize is used to set the size of buffers returned by // requestBuffers when a with and height of zero is requested. status_t setDefaultBufferSize(uint32_t w, uint32_t h); // setDefaultBufferCount set the buffer count. If the client has requested // a buffer count using setBufferCount, the server-buffer count will // take effect once the client sets the count back to zero. status_t setDefaultMaxBufferCount(int bufferCount); // setMaxAcquiredBufferCount sets the maximum number of buffers that can // be acquired by the consumer at one time. This call will fail if a // producer is connected to the BufferQueue. status_t setMaxAcquiredBufferCount(int maxAcquiredBuffers); // isSynchronousMode returns whether the SurfaceTexture 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 status_t setDefaultBufferFormat(uint32_t defaultFormat); // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer status_t setConsumerUsageBits(uint32_t usage); // setTransformHint bakes in rotation to buffers so overlays can be used status_t setTransformHint(uint32_t hint); private: // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage) // for the given slot. void freeBufferLocked(int index); // freeAllBuffersLocked frees the resources (both GraphicBuffer and // EGLImage) for all slots. void freeAllBuffersLocked(); // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer // and EGLImage) for all slots except the head of mQueue void freeAllBuffersExceptHeadLocked(); // drainQueueLocked drains the buffer queue if we're in synchronous mode // returns immediately otherwise. It returns NO_INIT if the BufferQueue // became abandoned or disconnected during this 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 current buffer. 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. 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; struct BufferSlot { BufferSlot() : mEglDisplay(EGL_NO_DISPLAY), mBufferState(BufferSlot::FREE), mRequestBufferCalled(false), mTransform(0), mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), mTimestamp(0), mFrameNumber(0), mEglFence(EGL_NO_SYNC_KHR), mAcquireCalled(false), mNeedsCleanupOnRelease(false) { mCrop.makeInvalid(); } // mGraphicBuffer points to the buffer allocated for this slot or is NULL // if no buffer has been allocated. sp<GraphicBuffer> mGraphicBuffer; // mEglDisplay is the EGLDisplay used to create mEglImage. EGLDisplay mEglDisplay; // BufferState represents the different states in which a buffer slot // can be. enum BufferState { // FREE indicates that the buffer is not currently being used and // will not be used in the future until it gets dequeued and // subsequently queued by the client. // aka "owned by BufferQueue, ready to be dequeued" FREE = 0, // DEQUEUED indicates that the buffer has been dequeued by the // client, but has not yet been queued or canceled. The buffer is // considered 'owned' by the client, and the server should not use // it for anything. // // Note that when in synchronous-mode (mSynchronousMode == true), // the buffer that's currently attached to the texture may be // dequeued by the client. That means that the current buffer can // be in either the DEQUEUED or QUEUED state. In asynchronous mode, // however, the current buffer is always in the QUEUED state. // aka "owned by producer, ready to be queued" DEQUEUED = 1, // QUEUED indicates that the buffer has been queued by the client, // and has not since been made available for the client to dequeue. // Attaching the buffer to the texture does NOT transition the // buffer away from the QUEUED state. However, in Synchronous mode // the current buffer may be dequeued by the client under some // circumstances. See the note about the current buffer in the // documentation for DEQUEUED. // aka "owned by BufferQueue, ready to be acquired" QUEUED = 2, // aka "owned by consumer, ready to be released" ACQUIRED = 3 }; // mBufferState is the current state of this buffer slot. BufferState mBufferState; // mRequestBufferCalled is used for validating that the client did // call requestBuffer() when told to do so. Technically this is not // needed but useful for debugging and catching client bugs. bool mRequestBufferCalled; // mCrop is the current crop rectangle for this buffer slot. Rect mCrop; // mTransform is the current transform flags for this buffer slot. // (example: NATIVE_WINDOW_TRANSFORM_ROT_90) uint32_t mTransform; // mScalingMode is the current scaling mode for this buffer slot. // (example: NATIVE_WINDOW_SCALING_MODE_FREEZE) 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; // 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 (optionally, based // on a compile-time option) set to a new sync object in updateTexImage. 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 empty. sp<Fence> mFence; // Indicates whether this buffer has been seen by a consumer yet bool mAcquireCalled; // Indicates whether this buffer needs to be cleaned up by consumer bool mNeedsCleanupOnRelease; }; // mSlots is the array of buffer slots that must be mirrored on the client // side. This allows buffer ownership to be transferred between the client // and server 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 requestBuffers() if a width and height of zero is specified. uint32_t mDefaultWidth; // mDefaultHeight holds the default height of allocated buffers. It is used // in requestBuffers() 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<IGraphicBufferAlloc> 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<ConsumerListener> mConsumerListener; // mSynchronousMode whether we're in synchronous mode or not bool mSynchronousMode; // mAllowSynchronousMode whether we allow synchronous mode or not const bool mAllowSynchronousMode; // mConnectedApi indicates the 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<int> Fifo; Fifo mQueue; // mAbandoned indicates that the BufferQueue will no longer be used to // consume images buffers pushed to it using the ISurfaceTexture interface. // It is initialized to false, and set to true in the abandon method. A // BufferQueue that has been abandoned will return the NO_INIT error from // all ISurfaceTexture methods capable of returning an error. bool mAbandoned; // mName is a string used to identify the BufferQueue in log messages. // It is set by the setName 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 for every buffer queued // with the surface Texture. uint64_t mFrameCounter; // mBufferHasBeenQueued is true once a buffer has been queued. It is reset // by 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