src/third_party/WebKit/Source/platform/fonts/harfbuzz/HarfBuzzFace.cpp

   1 /*
   2  * Copyright (c) 2012 Google Inc. All rights reserved.
   3  *
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   6  * met:
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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
  13  * distribution.
  14  *     * Neither the name of Google Inc. nor the names of its
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  16  * this software without specific prior written permission.
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  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/harfbuzz/HarfBuzzFace.h"
  33
  34 #include "platform/fonts/FontPlatformData.h"
  35 #include "hb-ot.h"
  36 #include "hb.h"
  37
  38 namespace blink {
  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, nullptr);
  86     if (result.isNewEntry)
  87         result.storedValue->value = FaceCacheEntry::create(createFace());
  88     result.storedValue->value->ref();
  89     m_face = result.storedValue->value->face();
  90     m_glyphCacheForFaceCacheEntry = result.storedValue->value->glyphCache();
  91 }
  92
  93 HarfBuzzFace::~HarfBuzzFace()
  94 {
  95     HarfBuzzFaceCache::iterator result = harfBuzzFaceCache()->find(m_uniqueID);
  96     ASSERT_WITH_SECURITY_IMPLICATION(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 blink