1 /*
2 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
3 * Copyright (C) 2003, 2004, 2006, 2007, 2009, 2010 Apple Inc. All right reserved.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
14 *
15 * You should have received a copy of the GNU Library General Public License
16 * along with this library; see the file COPYING.LIB. If not, write to
17 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
18 * Boston, MA 02110-1301, USA.
19 *
20 */
21
22 #include "config.h"
23 #include "platform/text/BidiContext.h"
24
25 #include "wtf/StdLibExtras.h"
26 #include "wtf/Vector.h"
27
28 namespace WebCore {
29
30 using namespace WTF::Unicode;
31
32 struct SameSizeAsBidiContext : public RefCounted<SameSizeAsBidiContext> {
33 uint32_t bitfields : 16;
34 void* parent;
35 };
36
37 COMPILE_ASSERT(sizeof(BidiContext) == sizeof(SameSizeAsBidiContext), BidiContext_should_stay_small);
38
createUncached(unsigned char level,Direction direction,bool override,BidiEmbeddingSource source,BidiContext * parent)39 inline PassRefPtr<BidiContext> BidiContext::createUncached(unsigned char level, Direction direction, bool override, BidiEmbeddingSource source, BidiContext* parent)
40 {
41 return adoptRef(new BidiContext(level, direction, override, source, parent));
42 }
43
create(unsigned char level,Direction direction,bool override,BidiEmbeddingSource source,BidiContext * parent)44 PassRefPtr<BidiContext> BidiContext::create(unsigned char level, Direction direction, bool override, BidiEmbeddingSource source, BidiContext* parent)
45 {
46 ASSERT(direction == (level % 2 ? RightToLeft : LeftToRight));
47
48 if (parent)
49 return createUncached(level, direction, override, source, parent);
50
51 ASSERT(level <= 1);
52 if (!level) {
53 if (!override) {
54 DEFINE_STATIC_REF(BidiContext, ltrContext, (createUncached(0, LeftToRight, false, FromStyleOrDOM, 0)));
55 return ltrContext;
56 }
57
58 DEFINE_STATIC_REF(BidiContext, ltrOverrideContext, (createUncached(0, LeftToRight, true, FromStyleOrDOM, 0)));
59 return ltrOverrideContext;
60 }
61
62 if (!override) {
63 DEFINE_STATIC_REF(BidiContext, rtlContext, (createUncached(1, RightToLeft, false, FromStyleOrDOM, 0)));
64 return rtlContext;
65 }
66
67 DEFINE_STATIC_REF(BidiContext, rtlOverrideContext, (createUncached(1, RightToLeft, true, FromStyleOrDOM, 0)));
68 return rtlOverrideContext;
69 }
70
copyContextAndRebaselineLevel(BidiContext * context,BidiContext * parent)71 static inline PassRefPtr<BidiContext> copyContextAndRebaselineLevel(BidiContext* context, BidiContext* parent)
72 {
73 ASSERT(context);
74 unsigned char newLevel = parent ? parent->level() : 0;
75 if (context->dir() == RightToLeft)
76 newLevel = nextGreaterOddLevel(newLevel);
77 else if (parent)
78 newLevel = nextGreaterEvenLevel(newLevel);
79
80 return BidiContext::create(newLevel, context->dir(), context->override(), context->source(), parent);
81 }
82
83 // The BidiContext stack must be immutable -- they're re-used for re-layout after
84 // DOM modification/editing -- so we copy all the non-unicode contexts, and
85 // recalculate their levels.
copyStackRemovingUnicodeEmbeddingContexts()86 PassRefPtr<BidiContext> BidiContext::copyStackRemovingUnicodeEmbeddingContexts()
87 {
88 Vector<BidiContext*, 64> contexts;
89 for (BidiContext* iter = this; iter; iter = iter->parent()) {
90 if (iter->source() != FromUnicode)
91 contexts.append(iter);
92 }
93 ASSERT(contexts.size());
94
95 RefPtr<BidiContext> topContext = copyContextAndRebaselineLevel(contexts.last(), 0);
96 for (int i = contexts.size() - 1; i > 0; --i)
97 topContext = copyContextAndRebaselineLevel(contexts[i - 1], topContext.get());
98
99 return topContext.release();
100 }
101
operator ==(const BidiContext & c1,const BidiContext & c2)102 bool operator==(const BidiContext& c1, const BidiContext& c2)
103 {
104 if (&c1 == &c2)
105 return true;
106 if (c1.level() != c2.level() || c1.override() != c2.override() || c1.dir() != c2.dir() || c1.source() != c2.source())
107 return false;
108 if (!c1.parent())
109 return !c2.parent();
110 return c2.parent() && *c1.parent() == *c2.parent();
111 }
112
113 } // namespace WebCore
114