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      1 /*
      2  * Copyright (C) 2013 Google 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 are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      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,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     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 WebCore {
     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 0;
     52 
     53     Cache::iterator result = m_cache.find(*platformData);
     54     if (result == m_cache.end()) {
     55         pair<RefPtr<SimpleFontData>, unsigned> newValue(SimpleFontData::create(*platformData), shouldRetain == Retain ? 1 : 0);
     56         m_cache.set(*platformData, newValue);
     57         if (shouldRetain == DoNotRetain)
     58             m_inactiveFontData.add(newValue.first);
     59         return newValue.first.release();
     60     }
     61 
     62     if (!result.get()->value.second) {
     63         ASSERT(m_inactiveFontData.contains(result.get()->value.first));
     64         m_inactiveFontData.remove(result.get()->value.first);
     65     }
     66 
     67     if (shouldRetain == Retain) {
     68         result.get()->value.second++;
     69     } else if (!result.get()->value.second) {
     70         // If shouldRetain is DoNotRetain and count is 0, we want to remove the fontData from
     71         // m_inactiveFontData (above) and re-add here to update LRU position.
     72         m_inactiveFontData.add(result.get()->value.first);
     73     }
     74 
     75     return result.get()->value.first;
     76 }
     77 
     78 bool FontDataCache::contains(const FontPlatformData* fontPlatformData) const
     79 {
     80     return m_cache.contains(*fontPlatformData);
     81 }
     82 
     83 void FontDataCache::release(const SimpleFontData* fontData)
     84 {
     85     ASSERT(!fontData->isCustomFont());
     86 
     87     Cache::iterator it = m_cache.find(fontData->platformData());
     88     ASSERT(it != m_cache.end());
     89     if (it == m_cache.end())
     90         return;
     91 
     92     ASSERT(it->value.second);
     93     if (!--it->value.second)
     94         m_inactiveFontData.add(it->value.first);
     95 }
     96 
     97 void FontDataCache::markAllVerticalData()
     98 {
     99 #if ENABLE(OPENTYPE_VERTICAL)
    100     Cache::iterator end = m_cache.end();
    101     for (Cache::iterator fontData = m_cache.begin(); fontData != end; ++fontData) {
    102         OpenTypeVerticalData* verticalData = const_cast<OpenTypeVerticalData*>(fontData->value.first->verticalData());
    103         if (verticalData)
    104             verticalData->setInFontCache(true);
    105     }
    106 #endif
    107 }
    108 
    109 bool FontDataCache::purge(PurgeSeverity PurgeSeverity)
    110 {
    111     if (PurgeSeverity == ForcePurge)
    112         return purgeLeastRecentlyUsed(INT_MAX);
    113 
    114     if (m_inactiveFontData.size() > cMaxInactiveFontData)
    115         return purgeLeastRecentlyUsed(m_inactiveFontData.size() - cTargetInactiveFontData);
    116 
    117     return false;
    118 }
    119 
    120 bool FontDataCache::purgeLeastRecentlyUsed(int count)
    121 {
    122     static bool isPurging; // Guard against reentry when e.g. a deleted FontData releases its small caps FontData.
    123     if (isPurging)
    124         return false;
    125 
    126     isPurging = true;
    127 
    128     Vector<RefPtr<SimpleFontData>, 20> fontDataToDelete;
    129     ListHashSet<RefPtr<SimpleFontData> >::iterator end = m_inactiveFontData.end();
    130     ListHashSet<RefPtr<SimpleFontData> >::iterator it = m_inactiveFontData.begin();
    131     for (int i = 0; i < count && it != end; ++it, ++i) {
    132         RefPtr<SimpleFontData>& fontData = *it.get();
    133         m_cache.remove(fontData->platformData());
    134         // We should not delete SimpleFontData here because deletion can modify m_inactiveFontData. See http://trac.webkit.org/changeset/44011
    135         fontDataToDelete.append(fontData);
    136     }
    137 
    138     if (it == end) {
    139         // Removed everything
    140         m_inactiveFontData.clear();
    141     } else {
    142         for (int i = 0; i < count; ++i)
    143             m_inactiveFontData.remove(m_inactiveFontData.begin());
    144     }
    145 
    146     bool didWork = fontDataToDelete.size();
    147 
    148     fontDataToDelete.clear();
    149 
    150     isPurging = false;
    151 
    152     return didWork;
    153 }
    154 
    155 }
    156