1/*
2 * Copyright (C) 2012, 2014 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 LayerPool_h
27#define LayerPool_h
28
29#include "IntSize.h"
30#include "IntSizeHash.h"
31#include "PlatformCALayer.h"
32#include "Timer.h"
33#include <wtf/Deque.h>
34#include <wtf/HashMap.h>
35#include <wtf/OwnPtr.h>
36#include <wtf/RetainPtr.h>
37#include <wtf/Vector.h>
38
39namespace WebCore {
40
41class LayerPool {
42    WTF_MAKE_NONCOPYABLE(LayerPool);
43public:
44    LayerPool();
45    ~LayerPool();
46
47    static HashSet<LayerPool*>& allLayerPools();
48
49    void addLayer(const RefPtr<PlatformCALayer>&);
50    RefPtr<PlatformCALayer> takeLayerWithSize(const IntSize&);
51
52    void drain();
53
54    // The maximum size of all queued layers in bytes.
55    unsigned capacity() const { return m_maxBytesForPool; }
56
57private:
58    typedef Deque<RefPtr<PlatformCALayer>> LayerList;
59
60    unsigned decayedCapacity() const;
61
62    bool canReuseLayerWithSize(const IntSize& size) const { return m_maxBytesForPool && !size.isEmpty(); }
63    void schedulePrune();
64    void pruneTimerFired(Timer<LayerPool>&);
65
66    typedef enum { LeaveUnchanged, MarkAsUsed } AccessType;
67    LayerList& listOfLayersWithSize(const IntSize&, AccessType = LeaveUnchanged);
68
69    static unsigned backingStoreBytesForSize(const IntSize&);
70
71    HashMap<IntSize, LayerList> m_reuseLists;
72    // Ordered by recent use. The last size is the most recently used.
73    Vector<IntSize> m_sizesInPruneOrder;
74    unsigned m_totalBytes;
75    unsigned m_maxBytesForPool;
76
77    Timer<LayerPool> m_pruneTimer;
78
79    double m_lastAddTime;
80};
81
82}
83
84#endif
85