/*
 * Copyright (C) 2007 Apple Inc. All rights reserved.
 *           (C) 2008 Nikolas Zimmermann <zimmermann@kde.org>
 *
 * 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 ContainerNodeAlgorithms_h
#define ContainerNodeAlgorithms_h

#include "core/dom/Document.h"
#include "core/html/HTMLFrameOwnerElement.h"
#include "core/inspector/InspectorInstrumentation.h"
#include "wtf/Assertions.h"

namespace WebCore {

class ChildNodeInsertionNotifier {
public:
    explicit ChildNodeInsertionNotifier(ContainerNode* insertionPoint)
        : m_insertionPoint(insertionPoint)
    {
    }

    void notify(Node*);

private:
    void notifyDescendantInsertedIntoDocument(ContainerNode*);
    void notifyDescendantInsertedIntoTree(ContainerNode*);
    void notifyNodeInsertedIntoDocument(Node*);
    void notifyNodeInsertedIntoTree(ContainerNode*);

    ContainerNode* m_insertionPoint;
    Vector< RefPtr<Node> > m_postInsertionNotificationTargets;
};

class ChildNodeRemovalNotifier {
public:
    explicit ChildNodeRemovalNotifier(ContainerNode* insertionPoint)
        : m_insertionPoint(insertionPoint)
    {
    }

    void notify(Node*);

private:
    void notifyDescendantRemovedFromDocument(ContainerNode*);
    void notifyDescendantRemovedFromTree(ContainerNode*);
    void notifyNodeRemovedFromDocument(Node*);
    void notifyNodeRemovedFromTree(ContainerNode*);

    ContainerNode* m_insertionPoint;
};

namespace Private {

    template<class GenericNode, class GenericNodeContainer>
    void addChildNodesToDeletionQueue(GenericNode*& head, GenericNode*& tail, GenericNodeContainer*);

}

// Helper functions for TreeShared-derived classes, which have a 'Node' style interface
// This applies to 'ContainerNode' and 'SVGElementInstance'
template<class GenericNode, class GenericNodeContainer>
inline void removeDetachedChildrenInContainer(GenericNodeContainer* container)
{
    // List of nodes to be deleted.
    GenericNode* head = 0;
    GenericNode* tail = 0;

    Private::addChildNodesToDeletionQueue<GenericNode, GenericNodeContainer>(head, tail, container);

    GenericNode* n;
    GenericNode* next;
    while ((n = head) != 0) {
        ASSERT(n->m_deletionHasBegun);

        next = n->nextSibling();
        n->setNextSibling(0);

        head = next;
        if (next == 0)
            tail = 0;

        if (n->hasChildNodes())
            Private::addChildNodesToDeletionQueue<GenericNode, GenericNodeContainer>(head, tail, static_cast<GenericNodeContainer*>(n));

        delete n;
    }
}

template<class GenericNode, class GenericNodeContainer>
inline void appendChildToContainer(GenericNode* child, GenericNodeContainer* container)
{
    child->setParentOrShadowHostNode(container);

    GenericNode* lastChild = container->lastChild();
    if (lastChild) {
        child->setPreviousSibling(lastChild);
        lastChild->setNextSibling(child);
    } else
        container->setFirstChild(child);

    container->setLastChild(child);
}

// Helper methods for removeDetachedChildrenInContainer, hidden from WebCore namespace
namespace Private {

    template<class GenericNode, class GenericNodeContainer, bool dispatchRemovalNotification>
    struct NodeRemovalDispatcher {
        static void dispatch(GenericNode*, GenericNodeContainer*)
        {
            // no-op, by default
        }
    };

    template<class GenericNode, class GenericNodeContainer>
    struct NodeRemovalDispatcher<GenericNode, GenericNodeContainer, true> {
        static void dispatch(GenericNode* node, GenericNodeContainer* container)
        {
            // Clean up any TreeScope to a removed tree.
            if (Document* containerDocument = container->ownerDocument())
                containerDocument->adoptIfNeeded(node);
            if (node->inDocument())
                ChildNodeRemovalNotifier(container).notify(node);
        }
    };

    template<class GenericNode>
    struct ShouldDispatchRemovalNotification {
        static const bool value = false;
    };

    template<>
    struct ShouldDispatchRemovalNotification<Node> {
        static const bool value = true;
    };

    template<class GenericNode, class GenericNodeContainer>
    void addChildNodesToDeletionQueue(GenericNode*& head, GenericNode*& tail, GenericNodeContainer* container)
    {
        // We have to tell all children that their parent has died.
        GenericNode* next = 0;
        for (GenericNode* n = container->firstChild(); n != 0; n = next) {
            ASSERT(!n->m_deletionHasBegun);

            next = n->nextSibling();
            n->setNextSibling(0);
            n->setParentOrShadowHostNode(0);
            container->setFirstChild(next);
            if (next)
                next->setPreviousSibling(0);

            if (!n->refCount()) {
#ifndef NDEBUG
                n->m_deletionHasBegun = true;
#endif
                // Add the node to the list of nodes to be deleted.
                // Reuse the nextSibling pointer for this purpose.
                if (tail)
                    tail->setNextSibling(n);
                else
                    head = n;

                tail = n;
            } else {
                RefPtr<GenericNode> protect(n); // removedFromDocument may remove remove all references to this node.
                NodeRemovalDispatcher<GenericNode, GenericNodeContainer, ShouldDispatchRemovalNotification<GenericNode>::value>::dispatch(n, container);
            }
        }

        container->setLastChild(0);
    }

} // namespace Private

inline void ChildNodeInsertionNotifier::notifyNodeInsertedIntoDocument(Node* node)
{
    ASSERT(m_insertionPoint->inDocument());
    RefPtr<Node> protect(node);
    if (Node::InsertionShouldCallDidNotifySubtreeInsertions == node->insertedInto(m_insertionPoint))
        m_postInsertionNotificationTargets.append(node);
    if (node->isContainerNode())
        notifyDescendantInsertedIntoDocument(toContainerNode(node));
}

inline void ChildNodeInsertionNotifier::notifyNodeInsertedIntoTree(ContainerNode* node)
{
    NoEventDispatchAssertion assertNoEventDispatch;
    ASSERT(!m_insertionPoint->inDocument());

    if (Node::InsertionShouldCallDidNotifySubtreeInsertions == node->insertedInto(m_insertionPoint))
        m_postInsertionNotificationTargets.append(node);
    notifyDescendantInsertedIntoTree(node);
}

inline void ChildNodeInsertionNotifier::notify(Node* node)
{
    ASSERT(!NoEventDispatchAssertion::isEventDispatchForbidden());

    InspectorInstrumentation::didInsertDOMNode(&node->document(), node);

    RefPtr<Document> protectDocument(&node->document());
    RefPtr<Node> protectNode(node);

    if (m_insertionPoint->inDocument())
        notifyNodeInsertedIntoDocument(node);
    else if (node->isContainerNode())
        notifyNodeInsertedIntoTree(toContainerNode(node));

    // Script runs in didNotifySubtreeInsertions so we should lazy attach before
    // to ensure that triggering a style recalc in script attaches all nodes that
    // were inserted.
    // FIXME: We should merge the lazy attach logic into the tree traversal in
    // notifyNodeInsertedIntoDocument.
    if (!node->attached() && node->parentNode() && node->parentNode()->attached())
        node->lazyAttach();

    for (size_t i = 0; i < m_postInsertionNotificationTargets.size(); ++i) {
        Node* node = m_postInsertionNotificationTargets[i].get();
        if (node->inDocument())
            node->didNotifySubtreeInsertionsToDocument();
    }
}

inline void ChildNodeRemovalNotifier::notifyNodeRemovedFromDocument(Node* node)
{
    ASSERT(m_insertionPoint->inDocument());
    node->removedFrom(m_insertionPoint);

    if (node->isContainerNode())
        notifyDescendantRemovedFromDocument(toContainerNode(node));
}

inline void ChildNodeRemovalNotifier::notifyNodeRemovedFromTree(ContainerNode* node)
{
    NoEventDispatchAssertion assertNoEventDispatch;
    ASSERT(!m_insertionPoint->inDocument());

    node->removedFrom(m_insertionPoint);
    notifyDescendantRemovedFromTree(node);
}

inline void ChildNodeRemovalNotifier::notify(Node* node)
{
    if (node->inDocument()) {
        notifyNodeRemovedFromDocument(node);
        node->document().notifyRemovePendingSheetIfNeeded();
    } else if (node->isContainerNode())
        notifyNodeRemovedFromTree(toContainerNode(node));
}

class ChildFrameDisconnector {
public:
    enum DisconnectPolicy {
        RootAndDescendants,
        DescendantsOnly
    };

    explicit ChildFrameDisconnector(Node* root)
        : m_root(root)
    {
    }

    void disconnect(DisconnectPolicy = RootAndDescendants);

private:
    void collectFrameOwners(Node* root);
    void collectFrameOwners(ElementShadow*);
    void disconnectCollectedFrameOwners();

    Vector<RefPtr<HTMLFrameOwnerElement>, 10> m_frameOwners;
    Node* m_root;
};

#ifndef NDEBUG
unsigned assertConnectedSubrameCountIsConsistent(Node*);
#endif

inline void ChildFrameDisconnector::collectFrameOwners(Node* root)
{
    if (!root->connectedSubframeCount())
        return;

    if (root->isHTMLElement() && root->isFrameOwnerElement())
        m_frameOwners.append(toHTMLFrameOwnerElement(root));

    for (Node* child = root->firstChild(); child; child = child->nextSibling())
        collectFrameOwners(child);

    ElementShadow* shadow = root->isElementNode() ? toElement(root)->shadow() : 0;
    if (shadow)
        collectFrameOwners(shadow);
}

inline void ChildFrameDisconnector::disconnectCollectedFrameOwners()
{
    // Must disable frame loading in the subtree so an unload handler cannot
    // insert more frames and create loaded frames in detached subtrees.
    SubframeLoadingDisabler disabler(m_root);

    for (unsigned i = 0; i < m_frameOwners.size(); ++i) {
        HTMLFrameOwnerElement* owner = m_frameOwners[i].get();
        // Don't need to traverse up the tree for the first owner since no
        // script could have moved it.
        if (!i || m_root->containsIncludingShadowDOM(owner))
            owner->disconnectContentFrame();
    }
}

inline void ChildFrameDisconnector::disconnect(DisconnectPolicy policy)
{
#ifndef NDEBUG
    assertConnectedSubrameCountIsConsistent(m_root);
#endif

    if (!m_root->connectedSubframeCount())
        return;

    if (policy == RootAndDescendants)
        collectFrameOwners(m_root);
    else {
        for (Node* child = m_root->firstChild(); child; child = child->nextSibling())
            collectFrameOwners(child);
    }

    disconnectCollectedFrameOwners();
}

} // namespace WebCore

#endif // ContainerNodeAlgorithms_h