DOMElementWriter.java
/*
* 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 org.apache.tools.ant.util;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.w3c.dom.Attr;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
/**
* Writes a DOM tree to a given Writer.
* warning: this utility currently does not declare XML Namespaces.
* <p>Utility class used by {@link org.apache.tools.ant.XmlLogger
* XmlLogger} and
* org.apache.tools.ant.taskdefs.optional.junit.XMLJUnitResultFormatter
* XMLJUnitResultFormatter}.</p>
*
*/
public class DOMElementWriter {
private static final int HEX = 16;
private static final String[] WS_ENTITIES = new String['\r' - '\t' + 1];
static {
for (int i = '\t'; i < '\r' + 1; i++) {
WS_ENTITIES[i - '\t'] = "&#x" + Integer.toHexString(i) + ";";
}
}
/** prefix for generated prefixes */
private static final String NS = "ns";
/** xml declaration is on by default */
private boolean xmlDeclaration = true;
/**
* XML Namespaces are ignored by default.
*/
private XmlNamespacePolicy namespacePolicy = XmlNamespacePolicy.IGNORE;
/**
* Map (URI to prefix) of known namespaces.
*/
private Map<String, String> nsPrefixMap = new HashMap<>();
/**
* Number of generated prefix to use next.
*/
private int nextPrefix = 0;
/**
* Map (Element to URI) of namespaces defined on a given element.
*/
private Map<Element, List<String>> nsURIByElement = new HashMap<>();
/**
* Whether namespaces should be ignored for elements and attributes.
*
* @since Ant 1.7
*/
public static class XmlNamespacePolicy {
private boolean qualifyElements;
private boolean qualifyAttributes;
/**
* Ignores namespaces for elements and attributes, the default.
*/
public static final XmlNamespacePolicy IGNORE =
new XmlNamespacePolicy(false, false);
/**
* Ignores namespaces for attributes.
*/
public static final XmlNamespacePolicy ONLY_QUALIFY_ELEMENTS =
new XmlNamespacePolicy(true, false);
/**
* Qualifies namespaces for elements and attributes.
*/
public static final XmlNamespacePolicy QUALIFY_ALL =
new XmlNamespacePolicy(true, true);
/**
* @param qualifyElements whether to qualify elements
* @param qualifyAttributes whether to qualify elements
*/
public XmlNamespacePolicy(boolean qualifyElements,
boolean qualifyAttributes) {
this.qualifyElements = qualifyElements;
this.qualifyAttributes = qualifyAttributes;
}
}
/**
* Create an element writer.
* The ?xml? declaration will be included, namespaces ignored.
*/
public DOMElementWriter() {
}
/**
* Create an element writer
* XML namespaces will be ignored.
* @param xmlDeclaration flag to indicate whether the ?xml? declaration
* should be included.
* @since Ant1.7
*/
public DOMElementWriter(boolean xmlDeclaration) {
this(xmlDeclaration, XmlNamespacePolicy.IGNORE);
}
/**
* Create an element writer
* XML namespaces will be ignored.
* @param xmlDeclaration flag to indicate whether the ?xml? declaration
* should be included.
* @param namespacePolicy the policy to use.
* @since Ant1.7
*/
public DOMElementWriter(boolean xmlDeclaration,
XmlNamespacePolicy namespacePolicy) {
this.xmlDeclaration = xmlDeclaration;
this.namespacePolicy = namespacePolicy;
}
private static String lSep = System.getProperty("line.separator");
// CheckStyle:VisibilityModifier OFF - bc
/**
* Don't try to be too smart but at least recognize the predefined
* entities.
*/
protected String[] knownEntities = {"gt", "amp", "lt", "apos", "quot"};
// CheckStyle:VisibilityModifier ON
/**
* Writes a DOM tree to a stream in UTF8 encoding. Note that
* it prepends the <?xml version='1.0' encoding='UTF-8'?> if
* the xmlDeclaration field is true.
* The indent number is set to 0 and a 2-space indent.
* @param root the root element of the DOM tree.
* @param out the outputstream to write to.
* @throws IOException if an error happens while writing to the stream.
*/
public void write(Element root, OutputStream out) throws IOException {
Writer wri = new OutputStreamWriter(out, "UTF8");
writeXMLDeclaration(wri);
write(root, wri, 0, " ");
wri.flush();
}
/**
* Writes the XML declaration if xmlDeclaration is true.
* @param wri the writer to write to.
* @throws IOException if there is an error.
* @since Ant 1.7.0
*/
public void writeXMLDeclaration(Writer wri) throws IOException {
if (xmlDeclaration) {
wri.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
}
}
/**
* Writes a DOM tree to a stream.
*
* @param element the Root DOM element of the tree
* @param out where to send the output
* @param indent number of
* @param indentWith string that should be used to indent the
* corresponding tag.
* @throws IOException if an error happens while writing to the stream.
*/
public void write(Element element, Writer out, int indent,
String indentWith)
throws IOException {
// Write child elements and text
NodeList children = element.getChildNodes();
boolean hasChildren = (children.getLength() > 0);
boolean hasChildElements = false;
openElement(element, out, indent, indentWith, hasChildren);
if (hasChildren) {
for (int i = 0; i < children.getLength(); i++) {
Node child = children.item(i);
switch (child.getNodeType()) {
case Node.ELEMENT_NODE:
hasChildElements = true;
if (i == 0) {
out.write(lSep);
}
write((Element) child, out, indent + 1, indentWith);
break;
case Node.TEXT_NODE:
out.write(encode(child.getNodeValue()));
break;
case Node.COMMENT_NODE:
out.write("<!--");
out.write(encode(child.getNodeValue()));
out.write("-->");
break;
case Node.CDATA_SECTION_NODE:
out.write("<![CDATA[");
encodedata(out, ((Text) child).getData());
out.write("]]>");
break;
case Node.ENTITY_REFERENCE_NODE:
out.write('&');
out.write(child.getNodeName());
out.write(';');
break;
case Node.PROCESSING_INSTRUCTION_NODE:
out.write("<?");
out.write(child.getNodeName());
String data = child.getNodeValue();
if (data != null && data.length() > 0) {
out.write(' ');
out.write(data);
}
out.write("?>");
break;
default:
// Do nothing
}
}
closeElement(element, out, indent, indentWith, hasChildElements);
}
}
/**
* Writes the opening tag - including all attributes -
* corresponding to a DOM element.
*
* @param element the DOM element to write
* @param out where to send the output
* @param indent number of
* @param indentWith string that should be used to indent the
* corresponding tag.
* @throws IOException if an error happens while writing to the stream.
*/
public void openElement(Element element, Writer out, int indent,
String indentWith)
throws IOException {
openElement(element, out, indent, indentWith, true);
}
/**
* Writes the opening tag - including all attributes -
* corresponding to a DOM element.
*
* @param element the DOM element to write
* @param out where to send the output
* @param indent number of
* @param indentWith string that should be used to indent the
* corresponding tag.
* @param hasChildren whether this element has children.
* @throws IOException if an error happens while writing to the stream.
* @since Ant 1.7
*/
public void openElement(Element element, Writer out, int indent,
String indentWith, boolean hasChildren)
throws IOException {
// Write indent characters
for (int i = 0; i < indent; i++) {
out.write(indentWith);
}
// Write element
out.write("<");
if (namespacePolicy.qualifyElements) {
String uri = getNamespaceURI(element);
String prefix = (String) nsPrefixMap.get(uri);
if (prefix == null) {
if (nsPrefixMap.isEmpty()) {
// steal default namespace
prefix = "";
} else {
prefix = NS + (nextPrefix++);
}
nsPrefixMap.put(uri, prefix);
addNSDefinition(element, uri);
}
if (!"".equals(prefix)) {
out.write(prefix);
out.write(":");
}
}
out.write(element.getTagName());
// Write attributes
NamedNodeMap attrs = element.getAttributes();
for (int i = 0; i < attrs.getLength(); i++) {
Attr attr = (Attr) attrs.item(i);
out.write(" ");
if (namespacePolicy.qualifyAttributes) {
String uri = getNamespaceURI(attr);
String prefix = (String) nsPrefixMap.get(uri);
if (prefix == null) {
prefix = NS + (nextPrefix++);
nsPrefixMap.put(uri, prefix);
addNSDefinition(element, uri);
}
out.write(prefix);
out.write(":");
}
out.write(attr.getName());
out.write("=\"");
out.write(encodeAttributeValue(attr.getValue()));
out.write("\"");
}
// write namespace declarations
List<String> uris = nsURIByElement.get(element);
if (uris != null) {
for (String uri : uris) {
String prefix = nsPrefixMap.get(uri);
out.write(" xmlns");
if (!"".equals(prefix)) {
out.write(":");
out.write(prefix);
}
out.write("=\"");
out.write(uri);
out.write("\"");
}
}
if (hasChildren) {
out.write(">");
} else {
removeNSDefinitions(element);
out.write(" />");
out.write(lSep);
out.flush();
}
}
/**
* Writes a DOM tree to a stream.
*
* @param element the Root DOM element of the tree
* @param out where to send the output
* @param indent number of
* @param indentWith string that should be used to indent the
* corresponding tag.
* @param hasChildren if true indent.
* @throws IOException if an error happens while writing to the stream.
*/
public void closeElement(Element element, Writer out, int indent,
String indentWith, boolean hasChildren)
throws IOException {
// If we had child elements, we need to indent before we close
// the element, otherwise we're on the same line and don't need
// to indent
if (hasChildren) {
for (int i = 0; i < indent; i++) {
out.write(indentWith);
}
}
// Write element close
out.write("</");
if (namespacePolicy.qualifyElements) {
String uri = getNamespaceURI(element);
String prefix = (String) nsPrefixMap.get(uri);
if (prefix != null && !"".equals(prefix)) {
out.write(prefix);
out.write(":");
}
removeNSDefinitions(element);
}
out.write(element.getTagName());
out.write(">");
out.write(lSep);
out.flush();
}
/**
* Escape <, >, &, ', " as their entities and
* drop characters that are illegal in XML documents.
* @param value the string to encode.
* @return the encoded string.
*/
public String encode(String value) {
return encode(value, false);
}
/**
* Escape <, >, &, ', " as their entities, \n,
* \r and \t as numeric entities and drop characters that are
* illegal in XML documents.
* @param value the string to encode.
* @return the encoded string.
*/
public String encodeAttributeValue(String value) {
return encode(value, true);
}
private String encode(final String value, final boolean encodeWhitespace) {
final int len = value.length();
final StringBuilder sb = new StringBuilder(len);
for (int i = 0; i < len; i++) {
final char c = value.charAt(i);
switch (c) {
case '<':
sb.append("<");
break;
case '>':
sb.append(">");
break;
case '\'':
sb.append("'");
break;
case '\"':
sb.append(""");
break;
case '&':
sb.append("&");
break;
case '\r':
case '\n':
case '\t':
if (encodeWhitespace) {
sb.append(WS_ENTITIES[c - '\t']);
} else {
sb.append(c);
}
break;
default:
if (isLegalCharacter(c)) {
sb.append(c);
}
break;
}
}
return sb.substring(0);
}
/**
* Drop characters that are illegal in XML documents.
*
* <p>Also ensure that we are not including an <code>]]></code>
* marker by replacing that sequence with
* <code>&#x5d;&#x5d;&gt;</code>.</p>
*
* <p>See XML 1.0 2.2 <a
* href="http://www.w3.org/TR/1998/REC-xml-19980210#charsets">
* http://www.w3.org/TR/1998/REC-xml-19980210#charsets</a> and
* 2.7 <a
* href="http://www.w3.org/TR/1998/REC-xml-19980210#sec-cdata-sect">http://www.w3.org/TR/1998/REC-xml-19980210#sec-cdata-sect</a>.</p>
* @param value the value to be encoded.
* @return the encoded value.
*/
public String encodedata(final String value) {
final StringWriter out = new StringWriter();
try {
encodedata(out, value);
} catch (IOException ex) {
throw new RuntimeException(ex); //NOSONAR
}
return out.toString();
}
/**
* Drop characters that are illegal in XML documents and write the
* rest to the given writer.
*
* <p>Also ensure that we are not including an <code>]]></code>
* marker by replacing that sequence with
* <code>&#x5d;&#x5d;&gt;</code>.</p>
*
* <p>See XML 1.0 2.2 <a
* href="http://www.w3.org/TR/1998/REC-xml-19980210#charsets">
* http://www.w3.org/TR/1998/REC-xml-19980210#charsets</a> and
* 2.7 <a
* href="http://www.w3.org/TR/1998/REC-xml-19980210#sec-cdata-sect">http://www.w3.org/TR/1998/REC-xml-19980210#sec-cdata-sect</a>.</p>
* @param value the value to be encoded.
* @param out where to write the encoded data to.
* @throws IOException if data cannot be written
*/
public void encodedata(final Writer out, final String value) throws IOException {
final int len = value.length();
int prevEnd = 0;
int cdataEndPos = value.indexOf("]]>");
while (prevEnd < len) {
final int end = (cdataEndPos < 0 ? len : cdataEndPos);
// Write out stretches of legal characters in the range [prevEnd, end).
for (int prevLegalCharPos = prevEnd; prevLegalCharPos < end;/*empty*/) {
int illegalCharPos;
for (illegalCharPos = prevLegalCharPos; true; ++illegalCharPos) {
if (illegalCharPos >= end
|| !isLegalCharacter(value.charAt(illegalCharPos))) {
break;
}
}
out.write(value, prevLegalCharPos, illegalCharPos - prevLegalCharPos);
prevLegalCharPos = illegalCharPos + 1;
}
if (cdataEndPos >= 0) {
out.write("]]]]><![CDATA[>");
prevEnd = cdataEndPos + 3;
cdataEndPos = value.indexOf("]]>", prevEnd);
} else {
prevEnd = end;
}
}
}
/**
* Is the given argument a character or entity reference?
* @param ent the value to be checked.
* @return true if it is an entity.
*/
public boolean isReference(String ent) {
if (!(ent.charAt(0) == '&') || !ent.endsWith(";")) {
return false;
}
if (ent.charAt(1) == '#') {
if (ent.charAt(2) == 'x') {
try {
// CheckStyle:MagicNumber OFF
Integer.parseInt(ent.substring(3, ent.length() - 1), HEX);
// CheckStyle:MagicNumber ON
return true;
} catch (NumberFormatException nfe) {
return false;
}
} else {
try {
Integer.parseInt(ent.substring(2, ent.length() - 1));
return true;
} catch (NumberFormatException nfe) {
return false;
}
}
}
String name = ent.substring(1, ent.length() - 1);
for (int i = 0; i < knownEntities.length; i++) {
if (name.equals(knownEntities[i])) {
return true;
}
}
return false;
}
/**
* Is the given character allowed inside an XML document?
*
* <p>See XML 1.0 2.2 <a
* href="http://www.w3.org/TR/1998/REC-xml-19980210#charsets">
* http://www.w3.org/TR/1998/REC-xml-19980210#charsets</a>.</p>
* @param c the character to test.
* @return true if the character is allowed.
* @since 1.10, Ant 1.5
*/
public boolean isLegalCharacter(final char c) {
// CheckStyle:MagicNumber OFF
if (c == 0x9 || c == 0xA || c == 0xD) {
return true;
}
if (c < 0x20) {
return false;
}
if (c <= 0xD7FF) {
return true;
}
if (c < 0xE000) {
return false;
}
if (c <= 0xFFFD) {
return true;
}
// CheckStyle:MagicNumber ON
return false;
}
private void removeNSDefinitions(Element element) {
List<String> uris = nsURIByElement.get(element);
if (uris != null) {
uris.forEach(nsPrefixMap::remove);
nsURIByElement.remove(element);
}
}
private void addNSDefinition(Element element, String uri) {
nsURIByElement.computeIfAbsent(element, e -> new ArrayList<>())
.add(uri);
}
private static String getNamespaceURI(Node n) {
String uri = n.getNamespaceURI();
return uri == null ? "" : uri;
}
}