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/*
* Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_DOM_TREE_ORDERED_MAP_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_DOM_TREE_ORDERED_MAP_H_
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/platform/heap/handle.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/forward.h"
#include "third_party/blink/renderer/platform/wtf/hash_map.h"
#include "third_party/blink/renderer/platform/wtf/text/atomic_string.h"
#include "third_party/blink/renderer/platform/wtf/text/atomic_string_hash.h"
#include "third_party/blink/renderer/platform/wtf/text/string_impl.h"
namespace blink {
class Element;
class HTMLSlotElement;
class TreeScope;
// TreeOrderedMap is a map from keys to |Element|s, which allows multiple values
// per key, maintained in tree order per key. Tree walks are avoided when
// possible by retaining a cached, ordered array of matching nodes. Adding or
// removing an element for a given key often clears the cache, forcing a tree
// walk upon the next access.
class CORE_EXPORT TreeOrderedMap : public GarbageCollected<TreeOrderedMap> {
public:
TreeOrderedMap();
void Add(const AtomicString&, Element&);
void Remove(const AtomicString&, Element&);
bool Contains(const AtomicString&) const;
bool ContainsMultiple(const AtomicString&) const;
// concrete instantiations of the get<>() method template
Element* GetElementById(const AtomicString&, const TreeScope&) const;
const HeapVector<Member<Element>>& GetAllElementsById(const AtomicString&,
const TreeScope&) const;
Element* GetElementByMapName(const AtomicString&, const TreeScope&) const;
HTMLSlotElement* GetSlotByName(const AtomicString&, const TreeScope&) const;
// Don't use this unless the caller can know the internal state of
// TreeOrderedMap exactly.
Element* GetCachedFirstElementWithoutAccessingNodeTree(const AtomicString&);
void Trace(Visitor*) const;
#if DCHECK_IS_ON()
// While removing a ContainerNode, ID lookups won't be precise should the tree
// have elements with duplicate IDs contained in the element being removed.
// Rare trees, but ID lookups may legitimately fail across such removals;
// this scope object informs TreeOrderedMaps about the transitory state of the
// underlying tree.
class CORE_EXPORT RemoveScope {
STACK_ALLOCATED();
public:
RemoveScope();
~RemoveScope();
};
#else
class CORE_EXPORT RemoveScope {
STACK_ALLOCATED();
public:
RemoveScope() {}
~RemoveScope() {}
};
#endif
private:
template <bool keyMatches(const AtomicString&, const Element&)>
Element* Get(const AtomicString&, const TreeScope&) const;
class MapEntry : public GarbageCollected<MapEntry> {
public:
explicit MapEntry(Element& first_element)
: element(first_element), count(1) {}
void Trace(Visitor*) const;
Member<Element> element;
unsigned count;
HeapVector<Member<Element>> ordered_list;
};
using Map = HeapHashMap<AtomicString, Member<MapEntry>>;
mutable Map map_;
};
inline bool TreeOrderedMap::Contains(const AtomicString& id) const {
return map_.Contains(id);
}
inline bool TreeOrderedMap::ContainsMultiple(const AtomicString& id) const {
Map::const_iterator it = map_.find(id);
return it != map_.end() && it->value->count > 1;
}
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_DOM_TREE_ORDERED_MAP_H_
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