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      1 /*
      2  * Copyright (C) 2011 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
     14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
     17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     23  * THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef DrawingAreaProxyImpl_h
     27 #define DrawingAreaProxyImpl_h
     28 
     29 #include "BackingStore.h"
     30 #include "DrawingAreaProxy.h"
     31 #include "LayerTreeContext.h"
     32 #include "RunLoop.h"
     33 #include <wtf/OwnPtr.h>
     34 #include <wtf/PassOwnPtr.h>
     35 
     36 namespace WebKit {
     37 
     38 class Region;
     39 
     40 class DrawingAreaProxyImpl : public DrawingAreaProxy {
     41 public:
     42     static PassOwnPtr<DrawingAreaProxyImpl> create(WebPageProxy*);
     43     virtual ~DrawingAreaProxyImpl();
     44 
     45     void paint(BackingStore::PlatformGraphicsContext, const WebCore::IntRect&, Region& unpaintedRegion);
     46 
     47 private:
     48     explicit DrawingAreaProxyImpl(WebPageProxy*);
     49 
     50     // DrawingAreaProxy
     51     virtual void didReceiveMessage(CoreIPC::Connection*, CoreIPC::MessageID, CoreIPC::ArgumentDecoder*);
     52     virtual void didReceiveSyncMessage(CoreIPC::Connection*, CoreIPC::MessageID, CoreIPC::ArgumentDecoder*, CoreIPC::ArgumentEncoder*);
     53     virtual bool paint(const WebCore::IntRect&, PlatformDrawingContext);
     54     virtual void sizeDidChange();
     55     virtual void visibilityDidChange();
     56     virtual void setPageIsVisible(bool);
     57     virtual void setBackingStoreIsDiscardable(bool);
     58 
     59     // CoreIPC message handlers
     60     virtual void update(uint64_t backingStoreStateID, const UpdateInfo&);
     61     virtual void didUpdateBackingStoreState(uint64_t backingStoreStateID, const UpdateInfo&, const LayerTreeContext&);
     62     virtual void enterAcceleratedCompositingMode(uint64_t backingStoreStateID, const LayerTreeContext&);
     63     virtual void exitAcceleratedCompositingMode(uint64_t backingStoreStateID, const UpdateInfo&);
     64 
     65     void incorporateUpdate(const UpdateInfo&);
     66 
     67     enum RespondImmediatelyOrNot { DoNotRespondImmediately, RespondImmediately };
     68     void backingStoreStateDidChange(RespondImmediatelyOrNot);
     69     void sendUpdateBackingStoreState(RespondImmediatelyOrNot);
     70     void waitForAndDispatchDidUpdateBackingStoreState();
     71 
     72 #if USE(ACCELERATED_COMPOSITING)
     73     void enterAcceleratedCompositingMode(const LayerTreeContext&);
     74     void exitAcceleratedCompositingMode();
     75 
     76     bool isInAcceleratedCompositingMode() const { return !m_layerTreeContext.isEmpty(); }
     77 #else
     78     bool isInAcceleratedCompositingMode() const { return false; }
     79 #endif
     80 
     81     void discardBackingStoreSoon();
     82     void discardBackingStore();
     83 
     84     // The state ID corresponding to our current backing store. Updated whenever we allocate
     85     // a new backing store. Any messages received that correspond to an earlier state are ignored,
     86     // as they don't apply to our current backing store.
     87     uint64_t m_currentBackingStoreStateID;
     88 
     89     // The next backing store state ID we will request the web process update to. Incremented
     90     // whenever our state changes in a way that will require a new backing store to be allocated.
     91     uint64_t m_nextBackingStoreStateID;
     92 
     93 #if USE(ACCELERATED_COMPOSITING)
     94     // The current layer tree context.
     95     LayerTreeContext m_layerTreeContext;
     96 #endif
     97 
     98     // Whether we've sent a UpdateBackingStoreState message and are now waiting for a DidUpdateBackingStoreState message.
     99     // Used to throttle UpdateBackingStoreState messages so we don't send them faster than the Web process can handle.
    100     bool m_isWaitingForDidUpdateBackingStoreState;
    101 
    102     bool m_isBackingStoreDiscardable;
    103     OwnPtr<BackingStore> m_backingStore;
    104 
    105     RunLoop::Timer<DrawingAreaProxyImpl> m_discardBackingStoreTimer;
    106 };
    107 
    108 } // namespace WebKit
    109 
    110 #endif // DrawingAreaProxyImpl_h
    111