1/*
2 * Copyright (C) 2007, 2015 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. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "HistoryItem.h"
29#include <wtf/Forward.h>
30#include <wtf/ListHashSet.h>
31#include <wtf/Noncopyable.h>
32
33namespace WebCore {
34
35class CachedPage;
36class Frame;
37class Page;
38
39enum class PruningReason { None, ProcessSuspended, MemoryPressure, ReachedMaxSize };
40
41class PageCache {
42 WTF_MAKE_NONCOPYABLE(PageCache); WTF_MAKE_FAST_ALLOCATED;
43public:
44 // Function to obtain the global page cache.
45 WEBCORE_EXPORT static PageCache& singleton();
46
47 bool canCache(Page&) const;
48
49 // Used when memory is low to prune some cached pages.
50 WEBCORE_EXPORT void pruneToSizeNow(unsigned maxSize, PruningReason);
51 WEBCORE_EXPORT void setMaxSize(unsigned); // number of pages to cache.
52 unsigned maxSize() const { return m_maxSize; }
53
54 WEBCORE_EXPORT bool addIfCacheable(HistoryItem&, Page*); // Prunes if maxSize() is exceeded.
55 WEBCORE_EXPORT void remove(HistoryItem&);
56 CachedPage* get(HistoryItem&, Page*);
57 std::unique_ptr<CachedPage> take(HistoryItem&, Page*);
58
59 void removeAllItemsForPage(Page&);
60
61 unsigned pageCount() const { return m_items.size(); }
62 WEBCORE_EXPORT unsigned frameCount() const;
63
64 void markPagesForDeviceOrPageScaleChanged(Page&);
65 void markPagesForContentsSizeChanged(Page&);
66#if ENABLE(VIDEO_TRACK)
67 void markPagesForCaptionPreferencesChanged();
68#endif
69
70private:
71 PageCache();
72 ~PageCache() = delete; // Make sure nobody accidentally calls delete -- WebCore does not delete singletons.
73
74 static bool canCachePageContainingThisFrame(Frame&);
75
76 void prune(PruningReason);
77 void dump() const;
78
79 ListHashSet<RefPtr<HistoryItem>> m_items;
80 unsigned m_maxSize {0};
81
82#if !ASSERT_DISABLED
83 bool m_isInRemoveAllItemsForPage { false };
84#endif
85
86 friend class WTF::NeverDestroyed<PageCache>;
87};
88
89} // namespace WebCore
90