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 <wtf/RunLoop.h>
33
34namespace WebCore {
35class Region;
36}
37
38namespace WebKit {
39
40class DrawingAreaProxyImpl : public DrawingAreaProxy {
41public:
42    explicit DrawingAreaProxyImpl(WebPageProxy*);
43    virtual ~DrawingAreaProxyImpl();
44
45    void paint(BackingStore::PlatformGraphicsContext, const WebCore::IntRect&, WebCore::Region& unpaintedRegion);
46
47    bool isInAcceleratedCompositingMode() const { return !m_layerTreeContext.isEmpty(); }
48
49    bool hasReceivedFirstUpdate() const { return m_hasReceivedFirstUpdate; }
50
51private:
52    // DrawingAreaProxy
53    virtual void sizeDidChange();
54    virtual void deviceScaleFactorDidChange();
55
56    virtual void setBackingStoreIsDiscardable(bool);
57    virtual void waitForBackingStoreUpdateOnNextPaint();
58
59    // IPC 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    virtual void updateAcceleratedCompositingMode(uint64_t backingStoreStateID, const LayerTreeContext&);
65
66    void incorporateUpdate(const UpdateInfo&);
67
68    enum RespondImmediatelyOrNot { DoNotRespondImmediately, RespondImmediately };
69    void backingStoreStateDidChange(RespondImmediatelyOrNot);
70    void sendUpdateBackingStoreState(RespondImmediatelyOrNot);
71    void waitForAndDispatchDidUpdateBackingStoreState();
72
73    void enterAcceleratedCompositingMode(const LayerTreeContext&);
74    void exitAcceleratedCompositingMode();
75    void updateAcceleratedCompositingMode(const LayerTreeContext&);
76
77    void discardBackingStoreSoon();
78    void discardBackingStore();
79
80    // The state ID corresponding to our current backing store. Updated whenever we allocate
81    // a new backing store. Any messages received that correspond to an earlier state are ignored,
82    // as they don't apply to our current backing store.
83    uint64_t m_currentBackingStoreStateID;
84
85    // The next backing store state ID we will request the web process update to. Incremented
86    // whenever our state changes in a way that will require a new backing store to be allocated.
87    uint64_t m_nextBackingStoreStateID;
88
89    // The current layer tree context.
90    LayerTreeContext m_layerTreeContext;
91
92    // Whether we've sent a UpdateBackingStoreState message and are now waiting for a DidUpdateBackingStoreState message.
93    // Used to throttle UpdateBackingStoreState messages so we don't send them faster than the Web process can handle.
94    bool m_isWaitingForDidUpdateBackingStoreState;
95
96    // For a new Drawing Area don't draw anything until the WebProcess has sent over the first content.
97    bool m_hasReceivedFirstUpdate;
98
99    bool m_isBackingStoreDiscardable;
100    std::unique_ptr<BackingStore> m_backingStore;
101
102    RunLoop::Timer<DrawingAreaProxyImpl> m_discardBackingStoreTimer;
103};
104
105} // namespace WebKit
106
107#endif // DrawingAreaProxyImpl_h
108