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