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/*
* 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();
// 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