/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package nokogiri.internals.c14n;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.ProcessingInstruction;
import org.w3c.dom.Text;
/**
* DOM and XML accessibility and comfort functions.
*
* @author Christian Geuer-Pollmann
*/
public class XMLUtils {
/**
* Constructor XMLUtils
*
*/
private XMLUtils() {
// we don't allow instantiation
}
/**
* Method getFullTextChildrenFromElement
*
* @param element
* @return the string of children
*/
public static String getFullTextChildrenFromElement(Element element) {
StringBuilder sb = new StringBuilder();
Node child = element.getFirstChild();
while (child != null) {
if (child.getNodeType() == Node.TEXT_NODE) {
sb.append(((Text)child).getData());
}
child = child.getNextSibling();
}
return sb.toString();
}
/**
* This method returns the owner document of a particular node.
* This method is necessary because it <I>always</I> returns a
* {@link Document}. {@link Node#getOwnerDocument} returns <CODE>null</CODE>
* if the {@link Node} is a {@link Document}.
*
* @param node
* @return the owner document of the node
*/
public static Document getOwnerDocument(Node node) {
if (node.getNodeType() == Node.DOCUMENT_NODE) {
return (Document) node;
}
try {
return node.getOwnerDocument();
} catch (NullPointerException npe) {
throw new NullPointerException(npe.getMessage());
}
}
/**
* This method returns the first non-null owner document of the Nodes in this Set.
* This method is necessary because it <I>always</I> returns a
* {@link Document}. {@link Node#getOwnerDocument} returns <CODE>null</CODE>
* if the {@link Node} is a {@link Document}.
*
* @param xpathNodeSet
* @return the owner document
*/
public static Document getOwnerDocument(Set<Node> xpathNodeSet) {
NullPointerException npe = null;
for (Node node : xpathNodeSet) {
int nodeType = node.getNodeType();
if (nodeType == Node.DOCUMENT_NODE) {
return (Document) node;
}
try {
if (nodeType == Node.ATTRIBUTE_NODE) {
return ((Attr)node).getOwnerElement().getOwnerDocument();
}
return node.getOwnerDocument();
} catch (NullPointerException e) {
npe = e;
}
}
throw new NullPointerException(npe.getMessage());
}
/**
* Method convertNodelistToSet
*
* @param xpathNodeSet
* @return the set with the nodelist
*/
public static Set<Node> convertNodelistToSet(NodeList xpathNodeSet) {
if (xpathNodeSet == null) {
return new HashSet<Node>();
}
int length = xpathNodeSet.getLength();
Set<Node> set = new HashSet<Node>(length);
for (int i = 0; i < length; i++) {
set.add(xpathNodeSet.item(i));
}
return set;
}
/**
* This method spreads all namespace attributes in a DOM document to their
* children. This is needed because the XML Signature XPath transform
* must evaluate the XPath against all nodes in the input, even against
* XPath namespace nodes. Through a bug in XalanJ2, the namespace nodes are
* not fully visible in the Xalan XPath model, so we have to do this by
* hand in DOM spaces so that the nodes become visible in XPath space.
*
* @param doc
* @see <A HREF="http://nagoya.apache.org/bugzilla/show_bug.cgi?id=2650">
* Namespace axis resolution is not XPath compliant </A>
*/
public static void circumventBug2650(Document doc) {
Element documentElement = doc.getDocumentElement();
// if the document element has no xmlns definition, we add xmlns=""
Attr xmlnsAttr =
documentElement.getAttributeNodeNS(Constants.NamespaceSpecNS, "xmlns");
if (xmlnsAttr == null) {
documentElement.setAttributeNS(Constants.NamespaceSpecNS, "xmlns", "");
}
XMLUtils.circumventBug2650internal(doc);
}
/**
* This is the work horse for {@link #circumventBug2650}.
*
* @param node
* @see <A HREF="http://nagoya.apache.org/bugzilla/show_bug.cgi?id=2650">
* Namespace axis resolution is not XPath compliant </A>
*/
@SuppressWarnings("fallthrough")
private static void circumventBug2650internal(Node node) {
Node parent = null;
Node sibling = null;
final String namespaceNs = Constants.NamespaceSpecNS;
do {
switch (node.getNodeType()) {
case Node.ELEMENT_NODE :
Element element = (Element) node;
if (!element.hasChildNodes()) {
break;
}
if (element.hasAttributes()) {
NamedNodeMap attributes = element.getAttributes();
int attributesLength = attributes.getLength();
for (Node child = element.getFirstChild(); child!=null;
child = child.getNextSibling()) {
if (child.getNodeType() != Node.ELEMENT_NODE) {
continue;
}
Element childElement = (Element) child;
for (int i = 0; i < attributesLength; i++) {
Attr currentAttr = (Attr) attributes.item(i);
if (!namespaceNs.equals(currentAttr.getNamespaceURI())) {
continue;
}
if (childElement.hasAttributeNS(namespaceNs,
currentAttr.getLocalName())) {
continue;
}
childElement.setAttributeNS(namespaceNs,
currentAttr.getName(),
currentAttr.getNodeValue());
}
}
}
case Node.ENTITY_REFERENCE_NODE :
case Node.DOCUMENT_NODE :
parent = node;
sibling = node.getFirstChild();
break;
}
while ((sibling == null) && (parent != null)) {
sibling = parent.getNextSibling();
parent = parent.getParentNode();
}
if (sibling == null) {
return;
}
node = sibling;
sibling = node.getNextSibling();
} while (true);
}
/**
* @param sibling
* @param uri
* @param nodeName
* @param number
* @return nodes with the constrain
*/
public static Text selectNodeText(Node sibling, String uri, String nodeName, int number) {
Node n = selectNode(sibling,uri,nodeName,number);
if (n == null) {
return null;
}
n = n.getFirstChild();
while (n != null && n.getNodeType() != Node.TEXT_NODE) {
n = n.getNextSibling();
}
return (Text)n;
}
/**
* @param sibling
* @param uri
* @param nodeName
* @param number
* @return nodes with the constrain
*/
public static Element selectNode(Node sibling, String uri, String nodeName, int number) {
while (sibling != null) {
if (sibling.getNamespaceURI() != null && sibling.getNamespaceURI().equals(uri)
&& sibling.getLocalName().equals(nodeName)) {
if (number == 0){
return (Element)sibling;
}
number--;
}
sibling = sibling.getNextSibling();
}
return null;
}
/**
* @param sibling
* @param uri
* @param nodeName
* @return nodes with the constraint
*/
public static Element[] selectNodes(Node sibling, String uri, String nodeName) {
List<Element> list = new ArrayList<Element>();
while (sibling != null) {
if (sibling.getNamespaceURI() != null && sibling.getNamespaceURI().equals(uri)
&& sibling.getLocalName().equals(nodeName)) {
list.add((Element)sibling);
}
sibling = sibling.getNextSibling();
}
return list.toArray(new Element[list.size()]);
}
/**
* @param signatureElement
* @param inputSet
* @return nodes with the constrain
*/
public static Set<Node> excludeNodeFromSet(Node signatureElement, Set<Node> inputSet) {
Set<Node> resultSet = new HashSet<Node>();
Iterator<Node> iterator = inputSet.iterator();
while (iterator.hasNext()) {
Node inputNode = iterator.next();
if (!XMLUtils.isDescendantOrSelf(signatureElement, inputNode)) {
resultSet.add(inputNode);
}
}
return resultSet;
}
/**
* Method getStrFromNode
*
* @param xpathnode
* @return the string for the node.
*/
public static String getStrFromNode(Node xpathnode) {
if (xpathnode.getNodeType() == Node.TEXT_NODE) {
// we iterate over all siblings of the context node because eventually,
// the text is "polluted" with pi's or comments
StringBuilder sb = new StringBuilder();
for (Node currentSibling = xpathnode.getParentNode().getFirstChild();
currentSibling != null;
currentSibling = currentSibling.getNextSibling()) {
if (currentSibling.getNodeType() == Node.TEXT_NODE) {
sb.append(((Text) currentSibling).getData());
}
}
return sb.toString();
} else if (xpathnode.getNodeType() == Node.ATTRIBUTE_NODE) {
return ((Attr) xpathnode).getNodeValue();
} else if (xpathnode.getNodeType() == Node.PROCESSING_INSTRUCTION_NODE) {
return ((ProcessingInstruction) xpathnode).getNodeValue();
}
return null;
}
/**
* Returns true if the descendantOrSelf is on the descendant-or-self axis
* of the context node.
*
* @param ctx
* @param descendantOrSelf
* @return true if the node is descendant
*/
public static boolean isDescendantOrSelf(Node ctx, Node descendantOrSelf) {
if (ctx == descendantOrSelf) {
return true;
}
Node parent = descendantOrSelf;
while (true) {
if (parent == null) {
return false;
}
if (parent == ctx) {
return true;
}
if (parent.getNodeType() == Node.ATTRIBUTE_NODE) {
parent = ((Attr) parent).getOwnerElement();
} else {
parent = parent.getParentNode();
}
}
}
/**
* Returns the attribute value for the attribute with the specified name.
* Returns null if there is no such attribute, or
* the empty string if the attribute value is empty.
*
* <p>This works around a limitation of the DOM
* <code>Element.getAttributeNode</code> method, which does not distinguish
* between an unspecified attribute and an attribute with a value of
* "" (it returns "" for both cases).
*
* @param elem the element containing the attribute
* @param name the name of the attribute
* @return the attribute value (may be null if unspecified)
*/
public static String getAttributeValue(Element elem, String name) {
Attr attr = elem.getAttributeNodeNS(null, name);
return (attr == null) ? null : attr.getValue();
}
/**
* This method is a tree-search to help prevent against wrapping attacks. It checks that no
* two Elements have ID Attributes that match the "value" argument, if this is the case then
* "false" is returned. Note that a return value of "true" does not necessarily mean that
* a matching Element has been found, just that no wrapping attack has been detected.
*/
public static boolean protectAgainstWrappingAttack(Node startNode, String value) {
Node startParent = startNode.getParentNode();
Node processedNode = null;
Element foundElement = null;
String id = value.trim();
if (id.charAt(0) == '#') {
id = id.substring(1);
}
while (startNode != null) {
if (startNode.getNodeType() == Node.ELEMENT_NODE) {
Element se = (Element) startNode;
NamedNodeMap attributes = se.getAttributes();
if (attributes != null) {
for (int i = 0; i < attributes.getLength(); i++) {
Attr attr = (Attr)attributes.item(i);
if (attr.isId() && id.equals(attr.getValue())) {
if (foundElement == null) {
// Continue searching to find duplicates
foundElement = attr.getOwnerElement();
} else {
//log.debug("Multiple elements with the same 'Id' attribute value!");
return false;
}
}
}
}
}
processedNode = startNode;
startNode = startNode.getFirstChild();
// no child, this node is done.
if (startNode == null) {
// close node processing, get sibling
startNode = processedNode.getNextSibling();
}
// no more siblings, get parent, all children
// of parent are processed.
while (startNode == null) {
processedNode = processedNode.getParentNode();
if (processedNode == startParent) {
return true;
}
// close parent node processing (processed node now)
startNode = processedNode.getNextSibling();
}
}
return true;
}
/**
* This method is a tree-search to help prevent against wrapping attacks. It checks that no other
* Element than the given "knownElement" argument has an ID attribute that matches the "value"
* argument, which is the ID value of "knownElement". If this is the case then "false" is returned.
*/
public static boolean protectAgainstWrappingAttack(
Node startNode, Element knownElement, String value
) {
Node startParent = startNode.getParentNode();
Node processedNode = null;
String id = value.trim();
if (id.charAt(0) == '#') {
id = id.substring(1);
}
while (startNode != null) {
if (startNode.getNodeType() == Node.ELEMENT_NODE) {
Element se = (Element) startNode;
NamedNodeMap attributes = se.getAttributes();
if (attributes != null) {
for (int i = 0; i < attributes.getLength(); i++) {
Attr attr = (Attr)attributes.item(i);
if (attr.isId() && id.equals(attr.getValue()) && se != knownElement) {
//log.debug("Multiple elements with the same 'Id' attribute value!");
return false;
}
}
}
}
processedNode = startNode;
startNode = startNode.getFirstChild();
// no child, this node is done.
if (startNode == null) {
// close node processing, get sibling
startNode = processedNode.getNextSibling();
}
// no more siblings, get parent, all children
// of parent are processed.
while (startNode == null) {
processedNode = processedNode.getParentNode();
if (processedNode == startParent) {
return true;
}
// close parent node processing (processed node now)
startNode = processedNode.getNextSibling();
}
}
return true;
}
}