/**

 * This file is part of the DOM implementation for KDE.

 *

 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)

 *           (C) 1999 Antti Koivisto (koivisto@kde.org)

 *           (C) 2001 Dirk Mueller (mueller@kde.org)

 * Copyright (C) 2004, 2006 Apple Computer, 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.

 */

#include "config.h"

#include "NodeList.h"

#include "Document.h"

#include "Element.h"

namespace WebCore {

NodeList::NodeList(PassRefPtr<Node> rootNode)

    : m_rootNode(rootNode)

    , m_caches(new Caches)

    , m_ownsCaches(true)

{

    m_rootNode->registerNodeList(this);

}    

NodeList::NodeList(PassRefPtr<Node> rootNode, NodeList::Caches* info)

    : m_rootNode(rootNode)

    , m_caches(info)

    , m_ownsCaches(false)

{

    m_rootNode->registerNodeList(this);

}    

NodeList::~NodeList()

{

    m_rootNode->unregisterNodeList(this);

    if (m_ownsCaches)

        delete m_caches;

}

unsigned NodeList::recursiveLength(Node* start) const

{

    if (!start)

        start = m_rootNode.get();

    if (m_caches->isLengthCacheValid && start == m_rootNode)

        return m_caches->cachedLength;

    unsigned len = 0;

    for (Node* n = start->firstChild(); n; n = n->nextSibling())

        if (n->isElementNode()) {

            if (nodeMatches(n))

                len++;

            len += recursiveLength(n);

        }

    if (start == m_rootNode) {

        m_caches->cachedLength = len;

        m_caches->isLengthCacheValid = true;

    }

    return len;

}

Node* NodeList::itemForwardsFromCurrent(Node* start, unsigned offset, int remainingOffset) const

{

    ASSERT(remainingOffset >= 0);

    for (Node *n = start; n; n = n->traverseNextNode(m_rootNode.get())) {

        if (n->isElementNode()) {

            if (nodeMatches(n)) {

                if (!remainingOffset) {

                    m_caches->lastItem = n;

                    m_caches->lastItemOffset = offset;

                    m_caches->isItemCacheValid = true;

                    return n;

                }

                remainingOffset--;

            }

        }

    }

    return 0; // no matching node in this subtree

}

Node* NodeList::itemBackwardsFromCurrent(Node* start, unsigned offset, int remainingOffset) const

{

    ASSERT(remainingOffset < 0);

    for (Node *n = start; n; n = n->traversePreviousNode(m_rootNode.get())) {

        if (n->isElementNode()) {

            if (nodeMatches(n)) {

                if (!remainingOffset) {

                    m_caches->lastItem = n;

                    m_caches->lastItemOffset = offset;

                    m_caches->isItemCacheValid = true;

                    return n;

                }

                remainingOffset++;

            }

        }

    }

    return 0; // no matching node in this subtree

}

Node* NodeList::recursiveItem(unsigned offset, Node* start) const

{

    int remainingOffset = offset;

    if (!start) {

        start = m_rootNode->firstChild();

        if (m_caches->isItemCacheValid) {

            if (offset == m_caches->lastItemOffset) {

                return m_caches->lastItem;

            } else if (offset > m_caches->lastItemOffset || m_caches->lastItemOffset - offset < offset) {

                start = m_caches->lastItem;

                remainingOffset -= m_caches->lastItemOffset;

            }

        }

    }

    if (remainingOffset < 0)

        return itemBackwardsFromCurrent(start, offset, remainingOffset);

    else

        return itemForwardsFromCurrent(start, offset, remainingOffset);

}

Node* NodeList::itemWithName(const AtomicString& elementId) const

{

    if (m_rootNode->isDocumentNode() || m_rootNode->inDocument()) {

        Node* node = m_rootNode->document()->getElementById(elementId);

        if (!node || !nodeMatches(node))

            return 0;

        for (Node* p = node->parentNode(); p; p = p->parentNode())

            if (p == m_rootNode)

                return node;

        return 0;

    }

    unsigned l = length();

    for (unsigned i = 0; i < l; i++) {

        Node* node = item(i);

        if (node->isElementNode() && static_cast<Element*>(node)->getIDAttribute() == elementId)

            return node;

    }

    return 0;

}

void NodeList::rootNodeChildrenChanged()

{

    m_caches->reset();

}

NodeList::Caches::Caches()

    : lastItem(0)

    , isLengthCacheValid(false)

    , isItemCacheValid(false)

{

}

void NodeList::Caches::reset()

{

    lastItem = 0;

    isLengthCacheValid = false;

    isItemCacheValid = false;     

}

}