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