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/*
* Copyright (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
* Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
*
* 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 LayoutCounter_h
#define LayoutCounter_h
#include "core/layout/LayoutText.h"
#include "core/style/CounterContent.h"
namespace blink {
class CounterNode;
// LayoutCounter is used to represent the text of a counter.
// See http://www.w3.org/TR/CSS21/generate.html#counters
//
// Counters are always generated content ("content: counter(a)") thus this
// LayoutObject is always anonymous.
//
// CounterNodes is where the logic for knowing the value of a counter is.
// LayoutCounter makes sure the CounterNodes tree is consistent with the
// style. It then just queries CounterNodes for their values.
//
// CounterNodes are rare so they are stored in a map instead of growing
// LayoutObject. counterMaps() (in LayoutCounter.cpp) keeps the association
// between LayoutObject and CounterNodes. To avoid unneeded hash-lookups in the
// common case where there is no CounterNode, LayoutObject also keeps track of
// whether it has at least one CounterNode in the hasCounterNodeMap bit.
//
// Keeping the map up-to-date is the reason why LayoutObjects need to call into
// LayoutCounter during their lifetime (see the static functions below).
class LayoutCounter final : public LayoutText {
public:
LayoutCounter(Document*, const CounterContent&);
~LayoutCounter() override;
// These functions are static so that any LayoutObject can call them.
// The reason is that any LayoutObject in the tree can have a CounterNode
// without a LayoutCounter (e.g. by specifying 'counter-increment' without
// a "content: counter(a)" directive)).
static void destroyCounterNodes(LayoutObject&);
static void destroyCounterNode(LayoutObject&, const AtomicString& identifier);
static void layoutObjectSubtreeAttached(LayoutObject*);
static void layoutObjectSubtreeWillBeDetached(LayoutObject*);
static void layoutObjectStyleChanged(LayoutObject&, const ComputedStyle* oldStyle, const ComputedStyle& newStyle);
void updateCounter();
const char* name() const override { return "LayoutCounter"; }
protected:
void willBeDestroyed() override;
private:
bool isOfType(LayoutObjectType type) const override { return type == LayoutObjectCounter || LayoutText::isOfType(type); }
PassRefPtr<StringImpl> originalText() const override;
// Removes the reference to the CounterNode associated with this layoutObject.
// This is used to cause a counter display update when the CounterNode tree changes.
void invalidate();
CounterContent m_counter;
CounterNode* m_counterNode;
LayoutCounter* m_nextForSameCounter;
friend class CounterNode;
};
DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutCounter, isCounter());
} // namespace blink
#ifndef NDEBUG
// Outside the WebCore namespace for ease of invocation from gdb.
void showCounterLayoutTree(const blink::LayoutObject*, const char* counterName = nullptr);
#endif
#endif // LayoutCounter_h
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