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95 lines
3.3 KiB
C++
95 lines
3.3 KiB
C++
/*
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* Copyright (C) 2000 Lars Knoll (knoll@kde.org)
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* Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All right reserved.
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* Copyright (C) 2010 Google Inc. All rights reserved.
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* Copyright (C) 2014 Adobe Systems Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public License
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* along with this library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*
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*/
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#ifndef TrailingObjects_h
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#define TrailingObjects_h
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#include "wtf/Vector.h"
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namespace blink {
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class InlineIterator;
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class RenderObject;
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class RenderText;
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struct BidiRun;
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template <class Iterator, class Run> class BidiResolver;
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template <class Iterator> class MidpointState;
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typedef BidiResolver<InlineIterator, BidiRun> InlineBidiResolver;
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typedef MidpointState<InlineIterator> LineMidpointState;
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// This class allows us to ensure lineboxes are created in the right place on the line when
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// an out-of-flow positioned object or an empty inline is encountered between a trailing space
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// and subsequent spaces and we want to ignore (i.e. collapse) surplus whitespace. So for example:
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// <div>X <span></span> Y</div>
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// or
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// <div>X <div style="position: absolute"></div> Y</div>
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// In both of the above snippets the inline and the positioned object occur after a trailing space
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// and before a space that will cause our line breaking algorithm to start ignoring spaces. When it
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// does that we want to ensure that the inline/positioned object gets a linebox and that it is part
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// of the collapsed whitespace. So to achieve this we use appendObjectIfNeeded() to keep track of
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// objects encountered after a trailing whitespace and updateMidpointsForTrailingObjects() to put
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// them in the right place when we start ignoring surplus whitespace.
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class TrailingObjects {
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public:
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TrailingObjects()
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: m_whitespace(0)
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{
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}
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void setTrailingWhitespace(RenderText* whitespace)
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{
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ASSERT(whitespace);
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m_whitespace = whitespace;
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}
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void clear()
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{
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m_whitespace = 0;
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// Using resize(0) rather than clear() here saves 2% on
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// PerformanceTests/Layout/line-layout.html because we avoid freeing and
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// re-allocating the underlying buffer repeatedly.
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m_objects.resize(0);
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}
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void appendObjectIfNeeded(RenderObject* object)
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{
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if (m_whitespace)
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m_objects.append(object);
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}
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enum CollapseFirstSpaceOrNot { DoNotCollapseFirstSpace, CollapseFirstSpace };
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void updateMidpointsForTrailingObjects(LineMidpointState&, const InlineIterator& lBreak, CollapseFirstSpaceOrNot);
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private:
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RenderText* m_whitespace;
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Vector<RenderObject*, 4> m_objects;
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};
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}
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#endif // TrailingObjects_h
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