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/*
* Copyright (C) 2013 Google 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 TreeNode_h
#define TreeNode_h
#include "wtf/Assertions.h"
namespace WTF {
//
// TreeNode is generic, ContainerNode-like linked tree data structure.
// There are a few notable difference between TreeNode and Node:
//
// * Each TreeNode node is NOT ref counted. The user have to retain its lifetime somehow.
// FIXME: lifetime management could be parameterized so that ref counted implementations can be used.
// * It ASSERT()s invalid input. The callers have to ensure that given parameter is sound.
// * There is no branch-leaf difference. Every node can be a parent of other node.
//
// FIXME: oilpan: Trace tree node edges to ensure we don't have dangling pointers.
// As it is used in HTMLImport it is safe since they all die together.
template <class T>
class TreeNode {
public:
typedef T NodeType;
TreeNode()
: m_next(0)
, m_previous(0)
, m_parent(0)
, m_firstChild(0)
, m_lastChild(0)
{
}
NodeType* next() const { return m_next; }
NodeType* previous() const { return m_previous; }
NodeType* parent() const { return m_parent; }
NodeType* firstChild() const { return m_firstChild; }
NodeType* lastChild() const { return m_lastChild; }
NodeType* here() const { return static_cast<NodeType*>(const_cast<TreeNode*>(this)); }
bool orphan() const { return !m_parent && !m_next && !m_previous && !m_firstChild && !m_lastChild; }
bool hasChildren() const { return m_firstChild; }
void insertBefore(NodeType* newChild, NodeType* refChild)
{
ASSERT(!newChild->parent());
ASSERT(!newChild->next());
ASSERT(!newChild->previous());
ASSERT(!refChild || this == refChild->parent());
if (!refChild) {
appendChild(newChild);
return;
}
NodeType* newPrevious = refChild->previous();
newChild->m_parent = here();
newChild->m_next = refChild;
newChild->m_previous = newPrevious;
refChild->m_previous = newChild;
if (newPrevious)
newPrevious->m_next = newChild;
else
m_firstChild = newChild;
}
void appendChild(NodeType* child)
{
ASSERT(!child->parent());
ASSERT(!child->next());
ASSERT(!child->previous());
child->m_parent = here();
if (!m_lastChild) {
ASSERT(!m_firstChild);
m_lastChild = m_firstChild = child;
return;
}
ASSERT(!m_lastChild->m_next);
NodeType* oldLast = m_lastChild;
m_lastChild = child;
child->m_previous = oldLast;
oldLast->m_next = child;
}
NodeType* removeChild(NodeType* child)
{
ASSERT(child->parent() == this);
if (m_firstChild == child)
m_firstChild = child->next();
if (m_lastChild == child)
m_lastChild = child->previous();
NodeType* oldNext = child->next();
NodeType* oldPrevious = child->previous();
child->m_parent = child->m_next = child->m_previous = 0;
if (oldNext)
oldNext->m_previous = oldPrevious;
if (oldPrevious)
oldPrevious->m_next = oldNext;
return child;
}
void takeChildrenFrom(NodeType* oldParent)
{
ASSERT(oldParent != this);
while (oldParent->hasChildren()) {
NodeType* child = oldParent->firstChild();
oldParent->removeChild(child);
this->appendChild(child);
}
}
private:
NodeType* m_next;
NodeType* m_previous;
NodeType* m_parent;
NodeType* m_firstChild;
NodeType* m_lastChild;
};
template<class T>
inline typename TreeNode<T>::NodeType* traverseNext(const TreeNode<T>* current, const TreeNode<T>* stayWithin = 0)
{
if (typename TreeNode<T>::NodeType* next = current->firstChild())
return next;
if (current == stayWithin)
return 0;
if (typename TreeNode<T>::NodeType* next = current->next())
return next;
for (typename TreeNode<T>::NodeType* parent = current->parent(); parent; parent = parent->parent()) {
if (parent == stayWithin)
return 0;
if (typename TreeNode<T>::NodeType* next = parent->next())
return next;
}
return 0;
}
template<class T>
inline typename TreeNode<T>::NodeType* traverseFirstPostOrder(const TreeNode<T>* current)
{
typename TreeNode<T>::NodeType* first = current->here();
while (first->firstChild())
first = first->firstChild();
return first;
}
template<class T>
inline typename TreeNode<T>::NodeType* traverseNextPostOrder(const TreeNode<T>* current, const TreeNode<T>* stayWithin = 0)
{
if (current == stayWithin)
return 0;
typename TreeNode<T>::NodeType* next = current->next();
if (!next)
return current->parent();
while (next->firstChild())
next = next->firstChild();
return next;
}
}
using WTF::TreeNode;
using WTF::traverseNext;
using WTF::traverseNextPostOrder;
#endif
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