com.sun.xml.wss.impl.dsig.DOMSubTreeData Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2021 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package com.sun.xml.wss.impl.dsig;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import javax.xml.crypto.NodeSetData;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.NoSuchElementException;
/**
* This is a subtype of NodeSetData that represents a dereferenced
* same-document URI as the root of a subdocument. The main reason is
* for efficiency and performance, as some transforms can operate
* directly on the subdocument and there is no need to convert it
* first to an XPath node-set.
*/
public class DOMSubTreeData implements NodeSetData {
private boolean excludeComments;
private Iterator ni;
private Node root;
public DOMSubTreeData(Node root, boolean excludeComments) {
this.root = root;
this.ni = new DelayedNodeIterator(root, excludeComments);
this.excludeComments = excludeComments;
}
@Override
public Iterator iterator() {
return ni;
}
public Node getRoot() {
return root;
}
public boolean excludeComments() {
return excludeComments;
}
/**
* This is an Iterator that contains a backing node-set that is
* not populated until the caller first attempts to advance the iterator.
*/
static class DelayedNodeIterator implements Iterator {
private Node root;
private List nodeSet;
private ListIterator li;
private boolean withComments;
DelayedNodeIterator(Node root, boolean excludeComments) {
this.root = root;
this.withComments = !excludeComments;
}
@Override
public boolean hasNext() {
if (nodeSet == null) {
nodeSet = dereferenceSameDocumentURI(root);
li = nodeSet.listIterator();
}
return li.hasNext();
}
@Override
public Object next() {
if (nodeSet == null) {
nodeSet = dereferenceSameDocumentURI(root);
li = nodeSet.listIterator();
}
if (li.hasNext()) {
return li.next();
} else {
throw new NoSuchElementException();
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
/**
* Dereferences a same-document URI fragment.
*
* @param node the node (document or element) referenced by the
* URI fragment. If null, returns an empty set.
* @return a set of nodes (minus any comment nodes)
*/
private List dereferenceSameDocumentURI(Node node) {
List nodeSet = new ArrayList();
if (node != null) {
nodeSetMinusCommentNodes(node, nodeSet, null);
}
return nodeSet;
}
/**
* Recursively traverses the subtree, and returns an XPath-equivalent
* node-set of all nodes traversed, excluding any comment nodes,
* if specified.
*
* @param node the node to traverse
* @param nodeSet the set of nodes traversed so far
* @param prevSibling the previous sibling node
*/
private void nodeSetMinusCommentNodes(Node node, List nodeSet,
Node prevSibling) {
switch (node.getNodeType()) {
case Node.ELEMENT_NODE :
NamedNodeMap attrs = node.getAttributes();
if (attrs != null) {
for (int i = 0, len = attrs.getLength(); i < len; i++) {
nodeSet.add(attrs.item(i));
}
}
nodeSet.add(node);
case Node.DOCUMENT_NODE :
Node pSibling = null;
for (Node child = node.getFirstChild(); child != null;
child = child.getNextSibling()) {
nodeSetMinusCommentNodes(child, nodeSet, pSibling);
pSibling = child;
}
break;
case Node.TEXT_NODE :
case Node.CDATA_SECTION_NODE:
// emulate XPath which only returns the first node in
// contiguous text/cdata nodes
if (prevSibling != null &&
(prevSibling.getNodeType() == Node.TEXT_NODE ||
prevSibling.getNodeType() == Node.CDATA_SECTION_NODE)){
return;
}
case Node.PROCESSING_INSTRUCTION_NODE :
nodeSet.add(node);
break;
case Node.COMMENT_NODE:
if (withComments) {
nodeSet.add(node);
}
}
}
}
}