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 "BidiContext.h"
24 #include <wtf/Vector.h>
25
26 namespace WebCore {
27
28 using namespace WTF::Unicode;
29
createUncached(unsigned char level,Direction direction,bool override,BidiEmbeddingSource source,BidiContext * parent)30 inline PassRefPtr<BidiContext> BidiContext::createUncached(unsigned char level, Direction direction, bool override, BidiEmbeddingSource source, BidiContext* parent)
31 {
32 return adoptRef(new BidiContext(level, direction, override, source, parent));
33 }
34
create(unsigned char level,Direction direction,bool override,BidiEmbeddingSource source,BidiContext * parent)35 PassRefPtr<BidiContext> BidiContext::create(unsigned char level, Direction direction, bool override, BidiEmbeddingSource source, BidiContext* parent)
36 {
37 ASSERT(direction == (level % 2 ? RightToLeft : LeftToRight));
38
39 if (parent)
40 return createUncached(level, direction, override, source, parent);
41
42 ASSERT(level <= 1);
43 if (!level) {
44 if (!override) {
45 static BidiContext* ltrContext = createUncached(0, LeftToRight, false, FromStyleOrDOM, 0).releaseRef();
46 return ltrContext;
47 }
48
49 static BidiContext* ltrOverrideContext = createUncached(0, LeftToRight, true, FromStyleOrDOM, 0).releaseRef();
50 return ltrOverrideContext;
51 }
52
53 if (!override) {
54 static BidiContext* rtlContext = createUncached(1, RightToLeft, false, FromStyleOrDOM, 0).releaseRef();
55 return rtlContext;
56 }
57
58 static BidiContext* rtlOverrideContext = createUncached(1, RightToLeft, true, FromStyleOrDOM, 0).releaseRef();
59 return rtlOverrideContext;
60 }
61
copyContextAndRebaselineLevel(BidiContext * context,BidiContext * parent)62 static inline PassRefPtr<BidiContext> copyContextAndRebaselineLevel(BidiContext* context, BidiContext* parent)
63 {
64 ASSERT(context);
65 unsigned char newLevel = parent ? parent->level() : 0;
66 if (context->dir() == RightToLeft)
67 newLevel = nextGreaterOddLevel(newLevel);
68 else if (parent)
69 newLevel = nextGreaterEvenLevel(newLevel);
70
71 return BidiContext::create(newLevel, context->dir(), context->override(), context->source(), parent);
72 }
73
74 // The BidiContext stack must be immutable -- they're re-used for re-layout after
75 // DOM modification/editing -- so we copy all the non-unicode contexts, and
76 // recalculate their levels.
copyStackRemovingUnicodeEmbeddingContexts()77 PassRefPtr<BidiContext> BidiContext::copyStackRemovingUnicodeEmbeddingContexts()
78 {
79 Vector<BidiContext*, 64> contexts;
80 for (BidiContext* iter = this; iter; iter = iter->parent()) {
81 if (iter->source() != FromUnicode)
82 contexts.append(iter);
83 }
84 ASSERT(contexts.size());
85
86 RefPtr<BidiContext> topContext = copyContextAndRebaselineLevel(contexts.last(), 0);
87 for (int i = contexts.size() - 1; i > 0; --i)
88 topContext = copyContextAndRebaselineLevel(contexts[i - 1], topContext.get());
89
90 return topContext.release();
91 }
92
operator ==(const BidiContext & c1,const BidiContext & c2)93 bool operator==(const BidiContext& c1, const BidiContext& c2)
94 {
95 if (&c1 == &c2)
96 return true;
97 if (c1.level() != c2.level() || c1.override() != c2.override() || c1.dir() != c2.dir() || c1.source() != c2.source())
98 return false;
99 if (!c1.parent())
100 return !c2.parent();
101 return c2.parent() && *c1.parent() == *c2.parent();
102 }
103
104 } // namespace WebCore
105