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 LegacyTileLayerPool_h
27#define LegacyTileLayerPool_h
28
29#if PLATFORM(IOS)
30
31#include "IntSize.h"
32#include "IntSizeHash.h"
33#include "Timer.h"
34#include <wtf/Deque.h>
35#include <wtf/HashMap.h>
36#include <wtf/NeverDestroyed.h>
37#include <wtf/OwnPtr.h>
38#include <wtf/RetainPtr.h>
39#include <wtf/Threading.h>
40#include <wtf/Vector.h>
41
42@class LegacyTileLayer;
43
44namespace WebCore {
45
46class LegacyTileLayerPool {
47    WTF_MAKE_NONCOPYABLE(LegacyTileLayerPool);
48public:
49    static LegacyTileLayerPool* sharedPool();
50
51    void addLayer(const RetainPtr<LegacyTileLayer>&);
52    RetainPtr<LegacyTileLayer> takeLayerWithSize(const IntSize&);
53
54    // The maximum size of all queued layers in bytes.
55    unsigned capacity() const { return m_capacity; }
56    void setCapacity(unsigned);
57    void drain();
58
59    unsigned decayedCapacity() const;
60
61    static unsigned bytesBackingLayerWithPixelSize(const IntSize&);
62
63private:
64    LegacyTileLayerPool();
65
66    typedef Deque<RetainPtr<LegacyTileLayer> > LayerList;
67
68    bool canReuseLayerWithSize(const IntSize& size) const { return m_capacity && !size.isEmpty(); }
69    void schedulePrune();
70    void prune();
71    typedef enum { LeaveUnchanged, MarkAsUsed } AccessType;
72    LayerList& listOfLayersWithSize(const IntSize&, AccessType = LeaveUnchanged);
73
74    HashMap<IntSize, LayerList> m_reuseLists;
75    // Ordered by recent use. The last size is the most recently used.
76    Vector<IntSize> m_sizesInPruneOrder;
77    unsigned m_totalBytes;
78    unsigned m_capacity;
79    Mutex m_layerPoolMutex;
80
81    double m_lastAddTime;
82    bool m_needsPrune;
83
84    friend NeverDestroyed<LegacyTileLayerPool>;
85};
86
87} // namespace WebCore
88
89#endif // PLATFORM(IOS)
90#endif // TileLayerPool_h
91