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 26namespace WebCore { 27 28using namespace WTF::Unicode; 29 30struct SameSizeAsBidiContext : public RefCounted<SameSizeAsBidiContext> { 31 uint32_t bitfields : 16; 32 void* parent; 33}; 34 35COMPILE_ASSERT(sizeof(BidiContext) == sizeof(SameSizeAsBidiContext), BidiContext_should_stay_small); 36 37inline PassRefPtr<BidiContext> BidiContext::createUncached(unsigned char level, Direction direction, bool override, BidiEmbeddingSource source, BidiContext* parent) 38{ 39 return adoptRef(new BidiContext(level, direction, override, source, parent)); 40} 41 42PassRefPtr<BidiContext> BidiContext::create(unsigned char level, Direction direction, bool override, BidiEmbeddingSource source, BidiContext* parent) 43{ 44 ASSERT(direction == (level % 2 ? RightToLeft : LeftToRight)); 45 46 if (parent) 47 return createUncached(level, direction, override, source, parent); 48 49 ASSERT(level <= 1); 50 if (!level) { 51 if (!override) { 52 static BidiContext* ltrContext = createUncached(0, LeftToRight, false, FromStyleOrDOM, 0).leakRef(); 53 return ltrContext; 54 } 55 56 static BidiContext* ltrOverrideContext = createUncached(0, LeftToRight, true, FromStyleOrDOM, 0).leakRef(); 57 return ltrOverrideContext; 58 } 59 60 if (!override) { 61 static BidiContext* rtlContext = createUncached(1, RightToLeft, false, FromStyleOrDOM, 0).leakRef(); 62 return rtlContext; 63 } 64 65 static BidiContext* rtlOverrideContext = createUncached(1, RightToLeft, true, FromStyleOrDOM, 0).leakRef(); 66 return rtlOverrideContext; 67} 68 69static inline PassRefPtr<BidiContext> copyContextAndRebaselineLevel(BidiContext* context, BidiContext* parent) 70{ 71 ASSERT(context); 72 unsigned char newLevel = parent ? parent->level() : 0; 73 if (context->dir() == RightToLeft) 74 newLevel = nextGreaterOddLevel(newLevel); 75 else if (parent) 76 newLevel = nextGreaterEvenLevel(newLevel); 77 78 return BidiContext::create(newLevel, context->dir(), context->override(), context->source(), parent); 79} 80 81// The BidiContext stack must be immutable -- they're re-used for re-layout after 82// DOM modification/editing -- so we copy all the non-unicode contexts, and 83// recalculate their levels. 84PassRefPtr<BidiContext> BidiContext::copyStackRemovingUnicodeEmbeddingContexts() 85{ 86 Vector<BidiContext*, 64> contexts; 87 for (BidiContext* iter = this; iter; iter = iter->parent()) { 88 if (iter->source() != FromUnicode) 89 contexts.append(iter); 90 } 91 ASSERT(contexts.size()); 92 93 RefPtr<BidiContext> topContext = copyContextAndRebaselineLevel(contexts.last(), 0); 94 for (int i = contexts.size() - 1; i > 0; --i) 95 topContext = copyContextAndRebaselineLevel(contexts[i - 1], topContext.get()); 96 97 return topContext.release(); 98} 99 100bool operator==(const BidiContext& c1, const BidiContext& c2) 101{ 102 if (&c1 == &c2) 103 return true; 104 if (c1.level() != c2.level() || c1.override() != c2.override() || c1.dir() != c2.dir() || c1.source() != c2.source()) 105 return false; 106 if (!c1.parent()) 107 return !c2.parent(); 108 return c2.parent() && *c1.parent() == *c2.parent(); 109} 110 111} // namespace WebCore 112