Merge "Refactored ISurfaceTexture calls from SurfaceTexture into BufferQueue."

Author: Jamie Gennis

include/gui/BufferQueue.h

@@ -0,0 +1,343 @@
+/*
+ * 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