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 "HarfBuzzFace.h"
33
34#include "FontPlatformData.h"
35#include "hb-ot.h"
36#include "hb.h"
37
38namespace WebCore {
39
40const hb_tag_t HarfBuzzFace::vertTag = HB_TAG('v', 'e', 'r', 't');
41const hb_tag_t HarfBuzzFace::vrt2Tag = HB_TAG('v', 'r', 't', '2');
42const hb_tag_t HarfBuzzFace::kernTag = HB_TAG('k', 'e', 'r', 'n');
43
44// Though we have FontCache class, which provides the cache mechanism for
45// WebKit's font objects, we also need additional caching layer for HarfBuzz
46// to reduce the memory consumption because hb_face_t should be associated with
47// underling font data (e.g. CTFontRef, FTFace).
48
49class FaceCacheEntry : public RefCounted<FaceCacheEntry> {
50public:
51    static PassRefPtr<FaceCacheEntry> create(hb_face_t* face)
52    {
53        ASSERT(face);
54        return adoptRef(new FaceCacheEntry(face));
55    }
56    ~FaceCacheEntry()
57    {
58        hb_face_destroy(m_face);
59    }
60
61    hb_face_t* face() { return m_face; }
62    HashMap<uint32_t, uint16_t>* glyphCache() { return &m_glyphCache; }
63
64private:
65    explicit FaceCacheEntry(hb_face_t* face)
66        : m_face(face)
67    { }
68
69    hb_face_t* m_face;
70    HashMap<uint32_t, uint16_t> m_glyphCache;
71};
72
73typedef HashMap<uint64_t, RefPtr<FaceCacheEntry>, WTF::IntHash<uint64_t>, WTF::UnsignedWithZeroKeyHashTraits<uint64_t> > HarfBuzzFaceCache;
74
75static HarfBuzzFaceCache* harfBuzzFaceCache()
76{
77    DEPRECATED_DEFINE_STATIC_LOCAL(HarfBuzzFaceCache, s_harfBuzzFaceCache, ());
78    return &s_harfBuzzFaceCache;
79}
80
81HarfBuzzFace::HarfBuzzFace(FontPlatformData* platformData, uint64_t uniqueID)
82    : m_platformData(platformData)
83    , m_uniqueID(uniqueID)
84    , m_scriptForVerticalText(HB_SCRIPT_INVALID)
85{
86    HarfBuzzFaceCache::AddResult result = harfBuzzFaceCache()->add(m_uniqueID, nullptr);
87    if (result.isNewEntry)
88        result.iterator->value = FaceCacheEntry::create(createFace());
89    result.iterator->value->ref();
90    m_face = result.iterator->value->face();
91    m_glyphCacheForFaceCacheEntry = result.iterator->value->glyphCache();
92}
93
94HarfBuzzFace::~HarfBuzzFace()
95{
96    HarfBuzzFaceCache::iterator result = harfBuzzFaceCache()->find(m_uniqueID);
97    ASSERT(result != harfBuzzFaceCache()->end());
98    ASSERT(result.get()->value->refCount() > 1);
99    result.get()->value->deref();
100    if (result.get()->value->refCount() == 1)
101        harfBuzzFaceCache()->remove(m_uniqueID);
102}
103
104static hb_script_t findScriptForVerticalGlyphSubstitution(hb_face_t* face)
105{
106    static const unsigned maxCount = 32;
107
108    unsigned scriptCount = maxCount;
109    hb_tag_t scriptTags[maxCount];
110    hb_ot_layout_table_get_script_tags(face, HB_OT_TAG_GSUB, 0, &scriptCount, scriptTags);
111    for (unsigned scriptIndex = 0; scriptIndex < scriptCount; ++scriptIndex) {
112        unsigned languageCount = maxCount;
113        hb_tag_t languageTags[maxCount];
114        hb_ot_layout_script_get_language_tags(face, HB_OT_TAG_GSUB, scriptIndex, 0, &languageCount, languageTags);
115        for (unsigned languageIndex = 0; languageIndex < languageCount; ++languageIndex) {
116            unsigned featureIndex;
117            if (hb_ot_layout_language_find_feature(face, HB_OT_TAG_GSUB, scriptIndex, languageIndex, HarfBuzzFace::vertTag, &featureIndex)
118                || hb_ot_layout_language_find_feature(face, HB_OT_TAG_GSUB, scriptIndex, languageIndex, HarfBuzzFace::vrt2Tag, &featureIndex))
119                return hb_ot_tag_to_script(scriptTags[scriptIndex]);
120        }
121    }
122    return HB_SCRIPT_INVALID;
123}
124
125void HarfBuzzFace::setScriptForVerticalGlyphSubstitution(hb_buffer_t* buffer)
126{
127    if (m_scriptForVerticalText == HB_SCRIPT_INVALID)
128        m_scriptForVerticalText = findScriptForVerticalGlyphSubstitution(m_face);
129    hb_buffer_set_script(buffer, m_scriptForVerticalText);
130}
131
132} // namespace WebCore
133