third_party/WebKit/Source/platform/fonts/FontDataCache.cpp

   1 /*
   2  * Copyright (C) 2013 Google Inc. All rights reserved.
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   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
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   9  * notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  * copyright notice, this list of conditions and the following disclaimer
  12  * in the documentation and/or other materials provided with the
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  14  *     * Neither the name of Google Inc. nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include "config.h"
  32 #include "platform/fonts/FontDataCache.h"
  33
  34 #include "platform/fonts/SimpleFontData.h"
  35
  36 using namespace WTF;
  37
  38 namespace blink {
  39
  40 #if !OS(ANDROID)
  41 const unsigned cMaxInactiveFontData = 250;
  42 const unsigned cTargetInactiveFontData = 200;
  43 #else
  44 const unsigned cMaxInactiveFontData = 225;
  45 const unsigned cTargetInactiveFontData = 200;
  46 #endif
  47
  48 PassRefPtr<SimpleFontData> FontDataCache::get(const FontPlatformData* platformData, ShouldRetain shouldRetain)
  49 {
  50     if (!platformData)
  51         return nullptr;
  52
  53     // TODO: crbug.com/446376 - This should not happen, but we currently
  54     // do not have a reproduction for the crash that an empty typeface()
  55     // causes downstream from here.
  56     if (!platformData->typeface()) {
  57         WTF_LOG_ERROR("Empty typeface() in FontPlatformData when accessing FontDataCache.");
  58         return nullptr;
  59     }
  60
  61     Cache::iterator result = m_cache.find(*platformData);
  62     if (result == m_cache.end()) {
  63         pair<RefPtr<SimpleFontData>, unsigned> newValue(SimpleFontData::create(*platformData), shouldRetain == Retain ? 1 : 0);
  64         m_cache.set(*platformData, newValue);
  65         if (shouldRetain == DoNotRetain)
  66             m_inactiveFontData.add(newValue.first);
  67         return newValue.first.release();
  68     }
  69
  70     if (!result.get()->value.second) {
  71         ASSERT(m_inactiveFontData.contains(result.get()->value.first));
  72         m_inactiveFontData.remove(result.get()->value.first);
  73     }
  74
  75     if (shouldRetain == Retain) {
  76         result.get()->value.second++;
  77     } else if (!result.get()->value.second) {
  78         // If shouldRetain is DoNotRetain and count is 0, we want to remove the fontData from
  79         // m_inactiveFontData (above) and re-add here to update LRU position.
  80         m_inactiveFontData.add(result.get()->value.first);
  81     }
  82
  83     return result.get()->value.first;
  84 }
  85
  86 bool FontDataCache::contains(const FontPlatformData* fontPlatformData) const
  87 {
  88     return m_cache.contains(*fontPlatformData);
  89 }
  90
  91 void FontDataCache::release(const SimpleFontData* fontData)
  92 {
  93     ASSERT(!fontData->isCustomFont());
  94
  95     Cache::iterator it = m_cache.find(fontData->platformData());
  96     ASSERT(it != m_cache.end());
  97     if (it == m_cache.end())
  98         return;
  99
 100     ASSERT(it->value.second);
 101     if (!--it->value.second)
 102         m_inactiveFontData.add(it->value.first);
 103 }
 104
 105 void FontDataCache::markAllVerticalData()
 106 {
 107     Cache::iterator end = m_cache.end();
 108     for (Cache::iterator fontData = m_cache.begin(); fontData != end; ++fontData) {
 109         OpenTypeVerticalData* verticalData = const_cast<OpenTypeVerticalData*>(fontData->value.first->verticalData());
 110         if (verticalData)
 111             verticalData->setInFontCache(true);
 112     }
 113 }
 114
 115 bool FontDataCache::purge(PurgeSeverity PurgeSeverity)
 116 {
 117     if (PurgeSeverity == ForcePurge)
 118         return purgeLeastRecentlyUsed(INT_MAX);
 119
 120     if (m_inactiveFontData.size() > cMaxInactiveFontData)
 121         return purgeLeastRecentlyUsed(m_inactiveFontData.size() - cTargetInactiveFontData);
 122
 123     return false;
 124 }
 125
 126 bool FontDataCache::purgeLeastRecentlyUsed(int count)
 127 {
 128     static bool isPurging; // Guard against reentry when e.g. a deleted FontData releases its small caps FontData.
 129     if (isPurging)
 130         return false;
 131
 132     isPurging = true;
 133
 134     Vector<RefPtr<SimpleFontData>, 20> fontDataToDelete;
 135     ListHashSet<RefPtr<SimpleFontData>>::iterator end = m_inactiveFontData.end();
 136     ListHashSet<RefPtr<SimpleFontData>>::iterator it = m_inactiveFontData.begin();
 137     for (int i = 0; i < count && it != end; ++it, ++i) {
 138         RefPtr<SimpleFontData>& fontData = *it.get();
 139         m_cache.remove(fontData->platformData());
 140         // We should not delete SimpleFontData here because deletion can modify m_inactiveFontData. See http://trac.webkit.org/changeset/44011
 141         fontDataToDelete.append(fontData);
 142     }
 143
 144     if (it == end) {
 145         // Removed everything
 146         m_inactiveFontData.clear();
 147     } else {
 148         for (int i = 0; i < count; ++i)
 149             m_inactiveFontData.remove(m_inactiveFontData.begin());
 150     }
 151
 152     bool didWork = fontDataToDelete.size();
 153
 154     fontDataToDelete.clear();
 155
 156     isPurging = false;
 157
 158     return didWork;
 159 }
 160
 161 } // namespace blink