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Diffstat (limited to 'include/gui/BufferQueue.h')
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1 files changed, 345 insertions, 0 deletions
diff --git a/include/gui/BufferQueue.h b/include/gui/BufferQueue.h new file mode 100644 index 0000000..ae99160 --- /dev/null +++ b/include/gui/BufferQueue.h @@ -0,0 +1,345 @@ +/* + * 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 <gui/ISurfaceTexture.h> + +#include <surfaceflinger/IGraphicBufferAlloc.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 { + MIN_ASYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS + 1, + MIN_SYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS + }; + enum { NUM_BUFFER_SLOTS = 32 }; + enum { NO_CONNECTED_API = 0 }; + + struct FrameAvailableListener : 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; + }; + + // 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. + BufferQueue(bool allowSynchronousMode = true); + 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 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, 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, int64_t timestamp, + uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform); + virtual void cancelBuffer(int buf); + virtual status_t setCrop(const Rect& reg); + virtual status_t setTransform(uint32_t transform); + virtual status_t setScalingMode(int mode); + + // 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, + uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform); + + // 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); + +protected: + + // 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(); + + status_t setBufferCountServerLocked(int bufferCount); + + enum { INVALID_BUFFER_SLOT = -1 }; + + struct BufferSlot { + + BufferSlot() + : mEglImage(EGL_NO_IMAGE_KHR), + mEglDisplay(EGL_NO_DISPLAY), + mBufferState(BufferSlot::FREE), + mRequestBufferCalled(false), + mTransform(0), + mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), + mTimestamp(0), + mFrameNumber(0), + mFence(EGL_NO_SYNC_KHR) { + mCrop.makeInvalid(); + } + + // mGraphicBuffer points to the buffer allocated for this slot or is NULL + // if no buffer has been allocated. + sp<GraphicBuffer> mGraphicBuffer; + + // mEglImage is the EGLImage created from mGraphicBuffer. + EGLImageKHR mEglImage; + + // 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. + 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. + 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. + QUEUED = 2, + }; + + // 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. This gets + // set to mNextCrop each time queueBuffer gets called for this buffer. + Rect mCrop; + + // mTransform is the current transform flags for this buffer slot. This + // gets set to mNextTransform each time queueBuffer gets called for this + // slot. + uint32_t mTransform; + + // mScalingMode is the current scaling mode for this buffer slot. This + // gets set to mNextScalingMode each time queueBuffer gets called for + // this 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; + + // mFence 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 mFence; + }; + + // 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; + + // mPixelFormat holds the pixel format of allocated buffers. It is used + // in requestBuffers() if a format of zero is specified. + uint32_t mPixelFormat; + + // mBufferCount is the number of buffer slots that the client and server + // must maintain. It defaults to MIN_ASYNC_BUFFER_SLOTS and can be changed + // by calling setBufferCount or setBufferCountServer + int mBufferCount; + + // mClientBufferCount is the number of buffer slots requested by the client. + // The default is zero, which means the client doesn't care how many buffers + // there is. + int mClientBufferCount; + + // mServerBufferCount buffer count requested by the server-side + int mServerBufferCount; + + // mCurrentTexture is the buffer slot index of the buffer that is currently + // bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT, + // indicating that no buffer slot is currently bound to the texture. Note, + // however, that a value of INVALID_BUFFER_SLOT does not necessarily mean + // that no buffer is bound to the texture. A call to setBufferCount will + // reset mCurrentTexture to INVALID_BUFFER_SLOT. + int mCurrentTexture; + + // mNextCrop is the crop rectangle that will be used for the next buffer + // that gets queued. It is set by calling setCrop. + Rect mNextCrop; + + // mNextTransform is the transform identifier that will be used for the next + // buffer that gets queued. It is set by calling setTransform. + uint32_t mNextTransform; + + // mNextScalingMode is the scaling mode that will be used for the next + // buffers that get queued. It is set by calling setScalingMode. + int mNextScalingMode; + + // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to + // allocate new GraphicBuffer objects. + sp<IGraphicBufferAlloc> mGraphicBufferAlloc; + + // mFrameAvailableListener is the listener object that will be called when a + // new frame becomes available. If it is not NULL it will be called from + // queueBuffer. + sp<FrameAvailableListener> mFrameAvailableListener; + + // 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 mName; + + // 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; +}; + +// ---------------------------------------------------------------------------- +}; // namespace android + +#endif // ANDROID_GUI_BUFFERQUEUE_H |