gecko/dom/camera/GonkNativeWindow.h

/*
 * Copyright (C) 2010 The Android Open Source Project
 * Copyright (C) 2012 Mozilla Foundation
 *
 * 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 DOM_CAMERA_GONKNATIVEWINDOW_H
#define DOM_CAMERA_GONKNATIVEWINDOW_H

#include <stdint.h>
#include <sys/types.h>

#include <ui/egl/android_natives.h>

#include <utils/Errors.h>
#include <utils/RefBase.h>

#include <ui/GraphicBuffer.h>
#include <ui/Rect.h>
#include <utils/String8.h>
#include <utils/threads.h>

namespace android {

class GonkNativeWindow : public EGLNativeBase<ANativeWindow, GonkNativeWindow, RefBase>
{
public:
    enum { MIN_UNDEQUEUED_BUFFERS = 2 };
    enum { MIN_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS };
    enum { NUM_BUFFER_SLOTS = 32 };

    GonkNativeWindow();
    ~GonkNativeWindow(); // this class cannot be overloaded

    // ANativeWindow hooks
    static int hook_cancelBuffer(ANativeWindow* window, ANativeWindowBuffer* buffer);
    static int hook_dequeueBuffer(ANativeWindow* window, ANativeWindowBuffer** buffer);
    static int hook_lockBuffer(ANativeWindow* window, ANativeWindowBuffer* buffer);
    static int hook_perform(ANativeWindow* window, int operation, ...);
    static int hook_query(const ANativeWindow* window, int what, int* value);
    static int hook_queueBuffer(ANativeWindow* window, ANativeWindowBuffer* buffer);
    static int hook_setSwapInterval(ANativeWindow* window, int interval);

protected:
    virtual int cancelBuffer(ANativeWindowBuffer* buffer);
    virtual int dequeueBuffer(ANativeWindowBuffer** buffer);
    virtual int lockBuffer(ANativeWindowBuffer* buffer);
    virtual int perform(int operation, va_list args);
    virtual int query(int what, int* value) const;
    virtual int queueBuffer(ANativeWindowBuffer* buffer);
    virtual int setSwapInterval(int interval);

    virtual int setBufferCount(int bufferCount);
    virtual int setBuffersDimensions(int w, int h);
    virtual int setBuffersFormat(int format);
    virtual int setBuffersTimestamp(int64_t timestamp);
    virtual int setUsage(uint32_t reqUsage);

    // 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();

private:
    void init();

    int dispatchSetBufferCount(va_list args);
    int dispatchSetBuffersGeometry(va_list args);
    int dispatchSetBuffersDimensions(va_list args);
    int dispatchSetBuffersFormat(va_list args);
    int dispatchSetBuffersTimestamp(va_list args);
    int dispatchSetUsage(va_list args);

    int getSlotFromBufferLocked(android_native_buffer_t* buffer) const;

private:
    enum { INVALID_BUFFER_SLOT = -1 };

    struct BufferSlot {

        BufferSlot()
            : mGraphicBuffer(0),
              mBufferState(BufferSlot::FREE),
              mTimestamp(0),
              mFrameNumber(0){
        }

        // mGraphicBuffer points to the buffer allocated for this slot or is NULL
        // if no buffer has been allocated.
        sp<GraphicBuffer> mGraphicBuffer;

        // 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;

        // 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;
    };

    // 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];

    // mDequeueCondition condition used for dequeueBuffer in synchronous mode
    mutable Condition mDequeueCondition;

    // mTimestamp is the timestamp that will be used for the next buffer queue
    // operation. It defaults to NATIVE_WINDOW_TIMESTAMP_AUTO, which means that
    // a timestamp is auto-generated when queueBuffer is called.
    int64_t mTimestamp;

    // 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;

    // usage flag
    uint32_t mUsage;

    // 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;

    // mMutex is the mutex used to prevent concurrent access to the member
    // variables. It must be locked whenever the member variables are accessed.
    mutable Mutex mMutex;

    // mFrameCounter is the free running counter, incremented for every buffer queued
    uint64_t mFrameCounter;
};

}; // namespace android

#endif // DOM_CAMERA_GONKNATIVEWINDOW_H