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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 "core/layout/api/LineLayoutItem.h"
#include "core/layout/api/LineLayoutText.h"
#include "wtf/Allocator.h"
#include "wtf/Vector.h"
namespace blink {
class InlineIterator;
struct BidiRun;
struct BidiIsolatedRun;
template <class Iterator, class Run, class IsolatedRun>
class BidiResolver;
template <class Iterator>
class MidpointState;
typedef BidiResolver<InlineIterator, BidiRun, BidiIsolatedRun>
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 {
STACK_ALLOCATED();
public:
TrailingObjects() : m_whitespace(nullptr) {}
void setTrailingWhitespace(LineLayoutText whitespace) {
ASSERT(whitespace);
m_whitespace = whitespace;
}
void clear() {
m_whitespace = LineLayoutText();
// 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(LineLayoutItem object) {
if (m_whitespace)
m_objects.push_back(object);
}
enum CollapseFirstSpaceOrNot { DoNotCollapseFirstSpace, CollapseFirstSpace };
void updateMidpointsForTrailingObjects(LineMidpointState&,
const InlineIterator& lBreak,
CollapseFirstSpaceOrNot);
private:
LineLayoutText m_whitespace;
Vector<LineLayoutItem, 4> m_objects;
};
} // namespace blink
#endif // TrailingObjects_h
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