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      1 /*
      2  * Copyright (c) 2012 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
     13  * distribution.
     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 "core/platform/graphics/harfbuzz/HarfBuzzFace.h"
     33 
     34 #include "core/platform/graphics/FontPlatformData.h"
     35 #include "hb-ot.h"
     36 #include "hb.h"
     37 
     38 namespace WebCore {
     39 
     40 const hb_tag_t HarfBuzzFace::vertTag = HB_TAG('v', 'e', 'r', 't');
     41 const hb_tag_t HarfBuzzFace::vrt2Tag = HB_TAG('v', 'r', 't', '2');
     42 
     43 // Though we have FontCache class, which provides the cache mechanism for
     44 // WebKit's font objects, we also need additional caching layer for HarfBuzz
     45 // to reduce the memory consumption because hb_face_t should be associated with
     46 // underling font data (e.g. CTFontRef, FTFace).
     47 
     48 class FaceCacheEntry : public RefCounted<FaceCacheEntry> {
     49 public:
     50     static PassRefPtr<FaceCacheEntry> create(hb_face_t* face)
     51     {
     52         ASSERT(face);
     53         return adoptRef(new FaceCacheEntry(face));
     54     }
     55     ~FaceCacheEntry()
     56     {
     57         hb_face_destroy(m_face);
     58     }
     59 
     60     hb_face_t* face() { return m_face; }
     61     HashMap<uint32_t, uint16_t>* glyphCache() { return &m_glyphCache; }
     62 
     63 private:
     64     explicit FaceCacheEntry(hb_face_t* face)
     65         : m_face(face)
     66     { }
     67 
     68     hb_face_t* m_face;
     69     HashMap<uint32_t, uint16_t> m_glyphCache;
     70 };
     71 
     72 typedef HashMap<uint64_t, RefPtr<FaceCacheEntry>, WTF::IntHash<uint64_t>, WTF::UnsignedWithZeroKeyHashTraits<uint64_t> > HarfBuzzFaceCache;
     73 
     74 static HarfBuzzFaceCache* harfBuzzFaceCache()
     75 {
     76     DEFINE_STATIC_LOCAL(HarfBuzzFaceCache, s_harfBuzzFaceCache, ());
     77     return &s_harfBuzzFaceCache;
     78 }
     79 
     80 HarfBuzzFace::HarfBuzzFace(FontPlatformData* platformData, uint64_t uniqueID)
     81     : m_platformData(platformData)
     82     , m_uniqueID(uniqueID)
     83     , m_scriptForVerticalText(HB_SCRIPT_INVALID)
     84 {
     85     HarfBuzzFaceCache::AddResult result = harfBuzzFaceCache()->add(m_uniqueID, 0);
     86     if (result.isNewEntry)
     87         result.iterator->value = FaceCacheEntry::create(createFace());
     88     result.iterator->value->ref();
     89     m_face = result.iterator->value->face();
     90     m_glyphCacheForFaceCacheEntry = result.iterator->value->glyphCache();
     91 }
     92 
     93 HarfBuzzFace::~HarfBuzzFace()
     94 {
     95     HarfBuzzFaceCache::iterator result = harfBuzzFaceCache()->find(m_uniqueID);
     96     ASSERT(result != harfBuzzFaceCache()->end());
     97     ASSERT(result.get()->value->refCount() > 1);
     98     result.get()->value->deref();
     99     if (result.get()->value->refCount() == 1)
    100         harfBuzzFaceCache()->remove(m_uniqueID);
    101 }
    102 
    103 static hb_script_t findScriptForVerticalGlyphSubstitution(hb_face_t* face)
    104 {
    105     static const unsigned maxCount = 32;
    106 
    107     unsigned scriptCount = maxCount;
    108     hb_tag_t scriptTags[maxCount];
    109     hb_ot_layout_table_get_script_tags(face, HB_OT_TAG_GSUB, 0, &scriptCount, scriptTags);
    110     for (unsigned scriptIndex = 0; scriptIndex < scriptCount; ++scriptIndex) {
    111         unsigned languageCount = maxCount;
    112         hb_tag_t languageTags[maxCount];
    113         hb_ot_layout_script_get_language_tags(face, HB_OT_TAG_GSUB, scriptIndex, 0, &languageCount, languageTags);
    114         for (unsigned languageIndex = 0; languageIndex < languageCount; ++languageIndex) {
    115             unsigned featureIndex;
    116             if (hb_ot_layout_language_find_feature(face, HB_OT_TAG_GSUB, scriptIndex, languageIndex, HarfBuzzFace::vertTag, &featureIndex)
    117                 || hb_ot_layout_language_find_feature(face, HB_OT_TAG_GSUB, scriptIndex, languageIndex, HarfBuzzFace::vrt2Tag, &featureIndex))
    118                 return hb_ot_tag_to_script(scriptTags[scriptIndex]);
    119         }
    120     }
    121     return HB_SCRIPT_INVALID;
    122 }
    123 
    124 void HarfBuzzFace::setScriptForVerticalGlyphSubstitution(hb_buffer_t* buffer)
    125 {
    126     if (m_scriptForVerticalText == HB_SCRIPT_INVALID)
    127         m_scriptForVerticalText = findScriptForVerticalGlyphSubstitution(m_face);
    128     hb_buffer_set_script(buffer, m_scriptForVerticalText);
    129 }
    130 
    131 } // namespace WebCore
    132