Source/WebCore/platform/graphics/texmap/TextureMapperPlatformLayerProxy.h

/*
 * Copyright (C) 2015 Igalia S.L.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#if USE(COORDINATED_GRAPHICS)

#include "TextureMapperGLHeaders.h"
#include <wtf/Condition.h>
#include <wtf/Function.h>
#include <wtf/Lock.h>
#include <wtf/RunLoop.h>
#include <wtf/ThreadSafeRefCounted.h>
#include <wtf/Vector.h>

#ifndef NDEBUG
#include <wtf/Threading.h>
#endif

namespace WebCore {

class IntSize;
class TextureMapperGL;
class TextureMapperLayer;
class TextureMapperPlatformLayerBuffer;

class TextureMapperPlatformLayerProxy : public ThreadSafeRefCounted<TextureMapperPlatformLayerProxy> {
    WTF_MAKE_FAST_ALLOCATED();
public:
    class Compositor {
    public:
        virtual void onNewBufferAvailable() = 0;
    };

    TextureMapperPlatformLayerProxy();
    virtual ~TextureMapperPlatformLayerProxy();

    // To avoid multiple lock/release situation to update a single frame,
    // the implementation of TextureMapperPlatformLayerProxyProvider should
    // aquire / release the lock explicitly to use below methods.
    Lock& lock() WTF_RETURNS_LOCK(m_lock) { return m_lock; }
    std::unique_ptr<TextureMapperPlatformLayerBuffer> getAvailableBuffer(const IntSize&, GLint internalFormat);
    void pushNextBuffer(std::unique_ptr<TextureMapperPlatformLayerBuffer>&&);
    bool isActive();

    WEBCORE_EXPORT void activateOnCompositingThread(Compositor*, TextureMapperLayer*);
    WEBCORE_EXPORT void invalidate();

    WEBCORE_EXPORT void swapBuffer();
    void dropCurrentBufferWhilePreservingTexture(bool shouldWait = false);

    bool scheduleUpdateOnCompositorThread(Function<void()>&&);

private:
    void appendToUnusedBuffers(std::unique_ptr<TextureMapperPlatformLayerBuffer>);
    void scheduleReleaseUnusedBuffers();
    void releaseUnusedBuffersTimerFired();

    Compositor* m_compositor;
    TextureMapperLayer* m_targetLayer;

    std::unique_ptr<TextureMapperPlatformLayerBuffer> m_currentBuffer;
    std::unique_ptr<TextureMapperPlatformLayerBuffer> m_pendingBuffer;

    Lock m_lock;

    Lock m_wasBufferDroppedLock;
    Condition m_wasBufferDroppedCondition;
    bool m_wasBufferDropped WTF_GUARDED_BY_LOCK(m_wasBufferDroppedLock) { false };

    Vector<std::unique_ptr<TextureMapperPlatformLayerBuffer>> m_usedBuffers;
    std::unique_ptr<RunLoop::Timer<TextureMapperPlatformLayerProxy>> m_releaseUnusedBuffersTimer;

#ifndef NDEBUG
    RefPtr<Thread> m_compositorThread;
#endif

    void compositorThreadUpdateTimerFired();
    std::unique_ptr<RunLoop::Timer<TextureMapperPlatformLayerProxy>> m_compositorThreadUpdateTimer;
    Function<void()> m_compositorThreadUpdateFunction;
};

} // namespace WebCore

#endif // USE(COORDINATED_GRAPHICS)