node.cpp

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    if (this == stayWithin)
        return 0;
    if (previousSibling())
        return previousSibling();
    const Node *n = this;
    while (n && !n->previousSibling() && (!stayWithin || n->parentNode() != stayWithin))
        n = n->parentNode();
    if (n)
        return n->previousSibling();
    return 0;
}

void Node::checkSetPrefix(const AtomicString&, ExceptionCode& ec)
{
    // Perform error checking as required by spec for setting Node.prefix. Used by
    // Element::setPrefix() and Attr::setPrefix()

    // FIXME: Implement support for INVALID_CHARACTER_ERR: Raised if the specified prefix contains an illegal character.
    
    // NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
    if (isReadOnlyNode()) {
        ec = NO_MODIFICATION_ALLOWED_ERR;
        return;
    }

    // FIXME: Implement NAMESPACE_ERR: - Raised if the specified prefix is malformed
    // We have to comment this out, since it's used for attributes and tag names, and we've only
    // switched one over.
    /*
    // - if the namespaceURI of this node is null,
    // - if the specified prefix is "xml" and the namespaceURI of this node is different from
    //   "http://www.w3.org/XML/1998/namespace",
    // - if this node is an attribute and the specified prefix is "xmlns" and
    //   the namespaceURI of this node is different from "http://www.w3.org/2000/xmlns/",
    // - or if this node is an attribute and the qualifiedName of this node is "xmlns" [Namespaces].
    if ((namespacePart(id()) == noNamespace && id() > ID_LAST_TAG) ||
        (_prefix == "xml" && String(document()->namespaceURI(id())) != "http://www.w3.org/XML/1998/namespace")) {
        ec = NAMESPACE_ERR;
        return;
    }*/
}

bool Node::canReplaceChild(Node* newChild, Node*)
{
    if (newChild->nodeType() != DOCUMENT_FRAGMENT_NODE) {
        if (!childTypeAllowed(newChild->nodeType()))
            return false;
    } else {
        for (Node *n = newChild->firstChild(); n; n = n->nextSibling()) {
            if (!childTypeAllowed(n->nodeType())) 
                return false;
        }
    }
    return true;
}

void Node::checkReplaceChild(Node* newChild, Node* oldChild, ExceptionCode& ec)
{
    // Perform error checking as required by spec for adding a new child. Used by
    // appendChild(), replaceChild() and insertBefore()
    
    // Not mentioned in spec: throw NOT_FOUND_ERR if newChild is null
    if (!newChild) {
        ec = NOT_FOUND_ERR;
        return;
    }
    
    // NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly
    if (isReadOnlyNode()) {
        ec = NO_MODIFICATION_ALLOWED_ERR;
        return;
    }
    
    bool shouldAdoptChild = false;
    
    // WRONG_DOCUMENT_ERR: Raised if newChild was created from a different document than the one that
    // created this node.
    // We assume that if newChild is a DocumentFragment, all children are created from the same document
    // as the fragment itself (otherwise they could not have been added as children)
    if (newChild->document() != document()) {
        // but if the child is not in a document yet then loosen the
        // restriction, so that e.g. creating an element with the Option()
        // constructor and then adding it to a different document works,
        // as it does in Mozilla and Mac IE.
        if (!newChild->inDocument()) {
            shouldAdoptChild = true;
        } else {
            ec = WRONG_DOCUMENT_ERR;
            return;
        }
    }
    
    // HIERARCHY_REQUEST_ERR: Raised if this node is of a type that does not allow children of the type of the
    // newChild node, or if the node to append is one of this node's ancestors.
    
    // check for ancestor/same node
    if (newChild == this || isDescendantOf(newChild)) {
        ec = HIERARCHY_REQUEST_ERR;
        return;
    }
    
    if (!canReplaceChild(newChild, oldChild)) {
        ec = HIERARCHY_REQUEST_ERR;
        return;
    }
       
    // change the document pointer of newChild and all of its children to be the new document
    if (shouldAdoptChild)
        for (Node* node = newChild; node; node = node->traverseNextNode(newChild))
            node->setDocument(document());
}

void Node::checkAddChild(Node *newChild, ExceptionCode& ec)
{
    // Perform error checking as required by spec for adding a new child. Used by
    // appendChild(), replaceChild() and insertBefore()

    // Not mentioned in spec: throw NOT_FOUND_ERR if newChild is null
    if (!newChild) {
        ec = NOT_FOUND_ERR;
        return;
    }

    // NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly
    if (isReadOnlyNode()) {
        ec = NO_MODIFICATION_ALLOWED_ERR;
        return;
    }

    bool shouldAdoptChild = false;

    // WRONG_DOCUMENT_ERR: Raised if newChild was created from a different document than the one that
    // created this node.
    // We assume that if newChild is a DocumentFragment, all children are created from the same document
    // as the fragment itself (otherwise they could not have been added as children)
    if (newChild->document() != document()) {
        // but if the child is not in a document yet then loosen the
        // restriction, so that e.g. creating an element with the Option()
        // constructor and then adding it to a different document works,
        // as it does in Mozilla and Mac IE.
        if (!newChild->inDocument()) {
            shouldAdoptChild = true;
        } else {
            ec = WRONG_DOCUMENT_ERR;
            return;
        }
    }

    // HIERARCHY_REQUEST_ERR: Raised if this node is of a type that does not allow children of the type of the
    // newChild node, or if the node to append is one of this node's ancestors.

    // check for ancestor/same node
    if (newChild == this || isDescendantOf(newChild)) {
        ec = HIERARCHY_REQUEST_ERR;
        return;
    }
    
    if (newChild->nodeType() != DOCUMENT_FRAGMENT_NODE) {
        if (!childTypeAllowed(newChild->nodeType())) {
            ec = HIERARCHY_REQUEST_ERR;
            return;
        }
    }
    else {
        for (Node *n = newChild->firstChild(); n; n = n->nextSibling()) {
            if (!childTypeAllowed(n->nodeType())) {
                ec = HIERARCHY_REQUEST_ERR;
                return;
            }
        }
    }
    
    // change the document pointer of newChild and all of its children to be the new document
    if (shouldAdoptChild)
        for (Node* node = newChild; node; node = node->traverseNextNode(newChild))
            node->setDocument(document());
}

bool Node::isDescendantOf(const Node *other) const
{
    // Return true if other is an ancestor of this, otherwise false
    if (!other)
        return false;
    for (const Node *n = parentNode(); n; n = n->parentNode()) {
        if (n == other)
            return true;
    }
    return false;
}

bool Node::contains(const Node* node) const
{
    if (!node)
        return false;
    return this == node || node->isDescendantOf(this);
}

bool Node::childAllowed(Node* newChild)
{
    return childTypeAllowed(newChild->nodeType());
}

void Node::attach()
{
    ASSERT(!attached());
    ASSERT(!renderer() || (renderer()->style() && renderer()->parent()));

    // If this node got a renderer it may be the previousRenderer() of sibling text nodes and thus affect the
    // result of Text::rendererIsNeeded() for those nodes.
    if (renderer()) {
        for (Node* next = nextSibling(); next; next = next->nextSibling()) {
            if (next->renderer())
                break;
            if (!next->attached())
                break;  // Assume this means none of the following siblings are attached.
            if (next->isTextNode())
                next->createRendererIfNeeded();
        }
    }

    m_attached = true;
}

void Node::willRemove()
{
}

void Node::detach()
{
    m_inDetach = true;

    if (renderer())
        renderer()->destroy();
    setRenderer(0);

    Document* doc = document();
    if (m_hovered)
        doc->hoveredNodeDetached(this);
    if (m_inActiveChain)
        doc->activeChainNodeDetached(this);

    m_active = false;
    m_hovered = false;
    m_inActiveChain = false;
    m_attached = false;
    m_inDetach = false;
}

Node *Node::previousEditable() const
{
    Node *node = previousLeafNode();
    while (node) {
        if (node->isContentEditable())
            return node;
        node = node->previousLeafNode();
    }
    return 0;
}

Node *Node::nextEditable() const
{
    Node *node = nextLeafNode();
    while (node) {
        if (node->isContentEditable())
            return node;
        node = node->nextLeafNode();
    }
    return 0;
}

RenderObject * Node::previousRenderer()
{
    for (Node *n = previousSibling(); n; n = n->previousSibling()) {
        if (n->renderer())
            return n->renderer();
    }
    return 0;
}

RenderObject * Node::nextRenderer()
{
    // Avoid an O(n^2) problem with this function by not checking for nextRenderer() when the parent element hasn't even 
    // been attached yet.
    if (parent() && !parent()->attached())
        return 0;

    for (Node *n = nextSibling(); n; n = n->nextSibling()) {
        if (n->renderer())
            return n->renderer();
    }
    return 0;
}

// FIXME: This code is used by editing.  Seems like it could move over there and not pollute Node.
Node *Node::previousNodeConsideringAtomicNodes() const
{
    if (previousSibling()) {
        Node *n = previousSibling();
        while (!isAtomicNode(n) && n->lastChild())
            n = n->lastChild();
        return n;
    }
    else if (parentNode()) {
        return parentNode();
    }
    else {
        return 0;
    }
}

Node *Node::nextNodeConsideringAtomicNodes() const
{
    if (!isAtomicNode(this) && firstChild())
        return firstChild();
    if (nextSibling())
        return nextSibling();
    const Node *n = this;
    while (n && !n->nextSibling())
        n = n->parentNode();
    if (n)
        return n->nextSibling();
    return 0;
}

Node *Node::previousLeafNode() const
{
    Node *node = previousNodeConsideringAtomicNodes();
    while (node) {
        if (isAtomicNode(node))
            return node;
        node = node->previousNodeConsideringAtomicNodes();
    }
    return 0;
}

Node *Node::nextLeafNode() const
{
    Node *node = nextNodeConsideringAtomicNodes();
    while (node) {
        if (isAtomicNode(node))
            return node;
        node = node->nextNodeConsideringAtomicNodes();
    }
    return 0;
}

void Node::createRendererIfNeeded()
{
    if (!document()->shouldCreateRenderers())
        return;

    ASSERT(!renderer());
    
    Node* parent = parentNode();    
    ASSERT(parent);
    
    RenderObject* parentRenderer = parent->renderer();
    if (parentRenderer && parentRenderer->canHaveChildren()
#if ENABLE(SVG)
        && parent->childShouldCreateRenderer(this)
#endif
        ) {
        RefPtr<RenderStyle> style = styleForRenderer();
        if (rendererIsNeeded(style.get())) {
            if (RenderObject* r = createRenderer(document()->renderArena(), style.get())) {
                if (!parentRenderer->isChildAllowed(r, style.get()))
                    r->destroy();
                else {
                    setRenderer(r);
                    renderer()->setAnimatableStyle(style.release());
                    parentRenderer->addChild(renderer(), nextRenderer());
                }
            }
        }
    }
}

PassRefPtr<RenderStyle> Node::styleForRenderer()
{
    if (isElementNode())
        return document()->styleSelector()->styleForElement(static_cast<Element*>(this));
    return parentNode() && parentNode()->renderer() ? parentNode()->renderer()->style() : 0;
}

bool Node::rendererIsNeeded(RenderStyle *style)
{
    return (document()->documentElement() == this) || (style->display() != NONE);
}

RenderObject* Node::createRenderer(RenderArena*, RenderStyle*)
{
    ASSERT(false);
    return 0;
}
    
RenderStyle* Node::nonRendererRenderStyle() const
{ 
    return 0; 
}   

void Node::setRenderStyle(PassRefPtr<RenderStyle> s)
{
    if (m_renderer)
        m_renderer->setAnimatableStyle(s); 
}

RenderStyle* Node::computedStyle()
{
    return parent() ? parent()->computedStyle() : 0;
}

int Node::maxCharacterOffset() const
{
    ASSERT_NOT_REACHED();
    return 0;
}

// FIXME: Shouldn't these functions be in the editing code?  Code that asks questions about HTML in the core DOM class
// is obviously misplaced.
bool Node::canStartSelection() const
{
    if (isContentEditable())
        return true;
    return parent() ? parent()->canStartSelection() : true;
}

Node* Node::shadowAncestorNode()
{
#if ENABLE(SVG)
    // SVG elements living in a shadow tree only occour when <use> created them.
    // For these cases we do NOT want to return the shadowParentNode() here
    // but the actual shadow tree element - as main difference to the HTML forms
    // shadow tree concept. (This function _could_ be made virtual - opinions?)
    if (isSVGElement())
        return this;