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/* StreamSerializer.java --

   Copyright (C) 2004,2006 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2, or (at your option)

any later version.

GNU Classpath 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

General Public License for more details.

You should have received a copy of the GNU General Public License

along with GNU Classpath; see the file COPYING.  If not, write to the

Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301 USA.

Linking this library statically or dynamically with other modules is

making a combined work based on this library.  Thus, the terms and

conditions of the GNU General Public License cover the whole

combination.

As a special exception, the copyright holders of this library give you

permission to link this library with independent modules to produce an

executable, regardless of the license terms of these independent

modules, and to copy and distribute the resulting executable under

terms of your choice, provided that you also meet, for each linked

independent module, the terms and conditions of the license of that

module.  An independent module is a module which is not derived from

or based on this library.  If you modify this library, you may extend

this exception to your version of the library, but you are not

obligated to do so.  If you do not wish to do so, delete this

exception statement from your version. */

package gnu.xml.transform;

import gnu.java.lang.CPStringBuilder;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.nio.ByteBuffer;

import java.nio.CharBuffer;

import java.nio.charset.Charset;

import java.nio.charset.CharsetEncoder;

import java.util.Collection;

import java.util.Collections;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Iterator;

import java.util.LinkedList;

import java.util.Map;

import javax.xml.XMLConstants;

import org.w3c.dom.Attr;

import org.w3c.dom.Document;

import org.w3c.dom.DocumentType;

import org.w3c.dom.NamedNodeMap;

import org.w3c.dom.Node;

/**

 * Serializes a DOM node to an output stream.

 *

 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>

 */

public class StreamSerializer

{

  static final int SPACE = 0x20;

  static final int BANG = 0x21; // !

  static final int APOS = 0x27; // '

  static final int SLASH = 0x2f; // /

  static final int BRA = 0x3c; // <

  static final int KET = 0x3e; // >

  static final int EQ = 0x3d; // =

  /**

   * HTML 4.01 boolean attributes

   */

  static final Map HTML_BOOLEAN_ATTRIBUTES = new HashMap();

  static

  {

    HashSet set;

    set = new HashSet();

    set.add("nohref");

    HTML_BOOLEAN_ATTRIBUTES.put("area", set);

    set = new HashSet();

    set.add("ismap");

    HTML_BOOLEAN_ATTRIBUTES.put("img", set);

    set = new HashSet();

    set.add("declare");

    HTML_BOOLEAN_ATTRIBUTES.put("object", set);

    set = new HashSet();

    set.add("noshade");

    HTML_BOOLEAN_ATTRIBUTES.put("hr", set);

    set = new HashSet();

    set.add("compact");

    HTML_BOOLEAN_ATTRIBUTES.put("dl", set);

    HTML_BOOLEAN_ATTRIBUTES.put("ol", set);

    HTML_BOOLEAN_ATTRIBUTES.put("ul", set);

    HTML_BOOLEAN_ATTRIBUTES.put("dir", set);

    HTML_BOOLEAN_ATTRIBUTES.put("menu", set);

    set = new HashSet();

    set.add("checked");

    set.add("disabled");

    set.add("readonly");

    set.add("ismap");

    HTML_BOOLEAN_ATTRIBUTES.put("input", set);

    set = new HashSet();

    set.add("multiple");

    set.add("disabled");

    HTML_BOOLEAN_ATTRIBUTES.put("select", set);

    set = new HashSet();

    set.add("disabled");

    HTML_BOOLEAN_ATTRIBUTES.put("optgroup", set);

    set = new HashSet();

    set.add("selected");

    set.add("disabled");

    HTML_BOOLEAN_ATTRIBUTES.put("option", set);

    set = new HashSet();

    set.add("disabled");

    set.add("readonly");

    HTML_BOOLEAN_ATTRIBUTES.put("textarea", set);

    set = new HashSet();

    set.add("disabled");

    HTML_BOOLEAN_ATTRIBUTES.put("button", set);

    set = new HashSet();

    set.add("nowrap");

    HTML_BOOLEAN_ATTRIBUTES.put("th", set);

    HTML_BOOLEAN_ATTRIBUTES.put("td", set);

    set = new HashSet();

    set.add("noresize");

    HTML_BOOLEAN_ATTRIBUTES.put("frame", set);

    set = new HashSet();

    set.add("defer");

    HTML_BOOLEAN_ATTRIBUTES.put("script", set);

  }

  // HTML namespace URIs

  static final HashSet HTML_URIS = new HashSet();

  static {

    HTML_URIS.add("http://www.w3.org/1999/xhtml");

  }

  protected final String encoding;

  final Charset charset;

  final CharsetEncoder encoder;

  final int mode;

  final LinkedList namespaces;

  protected String eol;

  Collection cdataSectionElements = Collections.EMPTY_SET;

  protected boolean discardDefaultContent;

  protected boolean xmlDeclaration = true;

  // has a META element with the encoding been added?

  private boolean htmlEncoded;

  public StreamSerializer()

  {

    this(Stylesheet.OUTPUT_XML, null, null);

  }

  public StreamSerializer(String encoding)

  {

    this(Stylesheet.OUTPUT_XML, encoding, null);

  }

  public StreamSerializer(int mode, String encoding, String eol)

  {

    this.mode = mode;

    if (encoding == null)

      encoding = (mode == Stylesheet.OUTPUT_HTML) ? "ISO-8859-1" : "UTF-8";

    this.encoding = encoding.intern();

    charset = Charset.forName(this.encoding);

    encoder = charset.newEncoder();

    this.eol = (eol != null) ? eol : System.getProperty("line.separator");

    namespaces = new LinkedList();

  }

  void setCdataSectionElements(Collection c)

  {

    cdataSectionElements = c;

  }

  public void serialize(final Node node, final OutputStream out)

    throws IOException

  {

    serialize(node, out, false);

  }

  void serialize(Node node, final OutputStream out,

                 boolean convertToCdata)

    throws IOException

  {

    while (node != null)

      {

        Node next = node.getNextSibling();

        doSerialize(node, out, convertToCdata);

        node = next;

      }

  }

  private void doSerialize(final Node node, final OutputStream out,

                           boolean convertToCdata)

    throws IOException

  {

    if (out == null)

      throw new NullPointerException("no output stream");

    htmlEncoded = false;

    String value, prefix;

    Node children;

    String uri = node.getNamespaceURI();

    short nt = node.getNodeType();

    if (convertToCdata && nt == Node.TEXT_NODE)

      nt = Node.CDATA_SECTION_NODE;

    switch (nt)

      {

      case Node.ATTRIBUTE_NODE:

        prefix = node.getPrefix();

        if (XMLConstants.XMLNS_ATTRIBUTE_NS_URI.equals(uri) ||

            XMLConstants.XMLNS_ATTRIBUTE.equals(prefix) ||

            (prefix != null && prefix.startsWith("xmlns:")))

          {

            String nsuri = node.getNodeValue();

            if (isDefined(nsuri, prefix))

              break;

            String name = node.getLocalName();

            if (name == null)

              {

                // Namespace-unaware

                name = node.getNodeName();

                int ci = name.indexOf(':');

                if (ci != -1)

                  name = name.substring(ci + 1);

              }

            define(nsuri, name);

          }

        else if (uri != null && !isDefined(uri, prefix))

          {

            prefix = define(uri, prefix);

            String nsname = (prefix == null) ? "xmlns" : "xmlns:" + prefix;

            out.write(SPACE);

            out.write(encodeText(nsname));

            out.write(EQ);

            String nsvalue = "\"" + encode(uri, true, true) + "\"";

            out.write(nsvalue.getBytes(encoding));

          }

        out.write(SPACE);

        String a_nodeName = node.getNodeName();

        out.write(encodeText(a_nodeName));

        String a_nodeValue = node.getNodeValue();

        if (mode == Stylesheet.OUTPUT_HTML &&

            a_nodeName.equals(a_nodeValue) &&

            isHTMLBoolean((Attr) node, a_nodeName))

          break;

        out.write(EQ);

        value = "\"" + encode(a_nodeValue, true, true) + "\"";

        out.write(encodeText(value));

        break;

      case Node.ELEMENT_NODE:

        pushNamespaceContext();

        value = node.getNodeName();

        out.write(BRA);

        out.write(encodeText(value));

        prefix = node.getPrefix();

        if (uri != null && !isDefined(uri, prefix))

          {

            prefix = define(uri, prefix);

            String nsname = (prefix == null) ? "xmlns" : "xmlns:" + prefix;

            out.write(SPACE);

            out.write(encodeText(nsname));

            out.write(EQ);

            String nsvalue = "\"" + encode(uri, true, true) + "\"";

            out.write(encodeText(nsvalue));

          }

        NamedNodeMap attrs = node.getAttributes();

        if (attrs != null)

          {

            int len = attrs.getLength();

            for (int i = 0; i < len; i++)

              {

                Attr attr = (Attr) attrs.item(i);

                if (discardDefaultContent && !attr.getSpecified())

                  {

                    // NOOP

                  }

                else

                  serialize(attr, out, false);

              }

          }

        convertToCdata = cdataSectionElements.contains(value);

        children = node.getFirstChild();

        if (children == null)

          {

            out.write(SLASH);

            out.write(KET);

          }

        else

          {

            out.write(KET);

            serialize(children, out, convertToCdata);

            out.write(BRA);

            out.write(SLASH);

            out.write(encodeText(value));

            out.write(KET);

          }

        popNamespaceContext();

        break;

      case Node.TEXT_NODE:

        value = node.getNodeValue();

        if (!"yes".equals(node.getUserData("disable-output-escaping")) &&

            mode != Stylesheet.OUTPUT_TEXT)

          value = encode(value, false, false);

        out.write(encodeText(value));

        break;

      case Node.CDATA_SECTION_NODE:

        value = node.getNodeValue();

        // Where any instanceof of ]]> occur, split into multiple CDATA

        // sections

        int bbk = value.indexOf("]]>");

        while (bbk != -1)

          {

            String head = value.substring(0, bbk + 2);

            out.write(encodeText("<![CDATA[" + head + "]]>"));

            value = value.substring(bbk + 2);

            bbk = value.indexOf("]]>");

          }

        // Write final tail value

        out.write(encodeText("<![CDATA[" + value + "]]>"));

        break;

      case Node.COMMENT_NODE:

        value = "<!--" + node.getNodeValue() + "-->";

        out.write(encodeText(value));

        Node cp = node.getParentNode();

        if (cp != null && cp.getNodeType() == Node.DOCUMENT_NODE)

          out.write(encodeText(eol));

        break;

      case Node.DOCUMENT_NODE:

      case Node.DOCUMENT_FRAGMENT_NODE:

        if (mode == Stylesheet.OUTPUT_XML)

          {

            if ("UTF-16".equalsIgnoreCase(encoding))

              {

                out.write(0xfe);

                out.write(0xff);

              }

            if (!"yes".equals(node.getUserData("omit-xml-declaration")) &&

                xmlDeclaration)

              {

                Document doc = (node instanceof Document) ?

                  (Document) node : null;

                String version = (doc != null) ? doc.getXmlVersion() : null;

                if (version == null)

                  version = (String) node.getUserData("version");

                if (version == null)

                  version = "1.0";

                out.write(BRA);

                out.write(0x3f);

                out.write("xml version=\"".getBytes("US-ASCII"));

                out.write(version.getBytes("US-ASCII"));

                out.write(0x22);

                if (!("UTF-8".equalsIgnoreCase(encoding)))

                  {

                    out.write(" encoding=\"".getBytes("US-ASCII"));

                    out.write(encoding.getBytes("US-ASCII"));

                    out.write(0x22);

                  }

                if ((doc != null && doc.getXmlStandalone()) ||

                    "yes".equals(node.getUserData("standalone")))

                  out.write(" standalone=\"yes\"".getBytes("US-ASCII"));

                out.write(0x3f);

                out.write(KET);

                out.write(encodeText(eol));

              }

            // TODO warn if not outputting the declaration would be a

            // problem

          }

        else if (mode == Stylesheet.OUTPUT_HTML)

          {

            // Ensure that encoding is accessible if head element is present

            String mediaType = (String) node.getUserData("media-type");

            if (mediaType == null)

              mediaType = "text/html";

            String contentType = mediaType + "; charset=" +

              ((encoding.indexOf(' ') != -1) ?

                "\"" + encoding + "\"" :

                encoding);

            Document doc = (node instanceof Document) ? (Document) node :

              node.getOwnerDocument();

            Node html = null;

            for (Node ctx = node.getFirstChild(); ctx != null;

                 ctx = ctx.getNextSibling())

              {

                if (ctx.getNodeType() == Node.ELEMENT_NODE &&

                    isHTMLElement(ctx, "html"))

                  {

                    html = ctx;

                    break;

                  }

              }

            if (html != null)

              {

                Node head = null;

                for (Node ctx = html.getFirstChild(); ctx != null;

                     ctx = ctx.getNextSibling())

                  {

                    if (isHTMLElement(ctx, "head"))

                      {

                        head = ctx;

                        break;

                      }

                  }

                if (head != null)

                  {

                    Node meta = null;

                    Node metaContent = null;

                    for (Node ctx = head.getFirstChild(); ctx != null;

                         ctx = ctx.getNextSibling())

                      {

                        if (isHTMLElement(ctx, "meta"))

                          {

                            NamedNodeMap metaAttrs = ctx.getAttributes();

                            int len = metaAttrs.getLength();

                            String httpEquiv = null;

                            Node content = null;

                            for (int i = 0; i < len; i++)

                              {

                                Node attr = metaAttrs.item(i);

                                String attrName = attr.getNodeName();

                                if ("http-equiv".equalsIgnoreCase(attrName))

                                  httpEquiv = attr.getNodeValue();

                                else if ("content".equalsIgnoreCase(attrName))

                                  content = attr;

                              }

                            if ("Content-Type".equalsIgnoreCase(httpEquiv))

                              {

                                meta = ctx;

                                metaContent = content;

                                break;

                              }

                          }

                      }

                    if (meta == null)

                      {

                        meta = doc.createElement("meta");

                        // Insert first

                        Node first = head.getFirstChild();

                        if (first == null)

                          head.appendChild(meta);

                        else

                          head.insertBefore(meta, first);

                        Node metaHttpEquiv = doc.createAttribute("http-equiv");

                        meta.getAttributes().setNamedItem(metaHttpEquiv);

                        metaHttpEquiv.setNodeValue("Content-Type");

                      }

                    if (metaContent == null)

                      {

                        metaContent = doc.createAttribute("content");

                        meta.getAttributes().setNamedItem(metaContent);

                      }

                    metaContent.setNodeValue(contentType);

                    htmlEncoded = true;

                  }

              }

          }

        children = node.getFirstChild();

        if (children != null)

          serialize(children, out, convertToCdata);

        break;

      case Node.DOCUMENT_TYPE_NODE:

        DocumentType doctype = (DocumentType) node;

        out.write(BRA);

        out.write(BANG);

        out.write(encodeText("DOCTYPE "));

        value = doctype.getNodeName();

        out.write(encodeText(value));

        String publicId = doctype.getPublicId();

        if (publicId != null)

          {

            out.write(encodeText(" PUBLIC "));

            out.write(APOS);

            out.write(encodeText(publicId));

            out.write(APOS);

          }

        String systemId = doctype.getSystemId();

        if (systemId != null)

          {

            out.write(encodeText(" SYSTEM "));

            out.write(APOS);

            out.write(encodeText(systemId));

            out.write(APOS);

          }

        String internalSubset = doctype.getInternalSubset();

        if (internalSubset != null)

          {

            out.write(encodeText(internalSubset));

          }

        out.write(KET);

        out.write(eol.getBytes(encoding));

        break;

      case Node.ENTITY_REFERENCE_NODE:

        value = "&" + node.getNodeValue() + ";";

        out.write(encodeText(value));

        break;

      case Node.PROCESSING_INSTRUCTION_NODE:

        value = "<?" + node.getNodeName() + " " + node.getNodeValue() + "?>";

        out.write(encodeText(value));

        Node pp = node.getParentNode();

        if (pp != null && pp.getNodeType() == Node.DOCUMENT_NODE)

          {

            out.write(encodeText(eol));

          }

        break;

      default:

        System.err.println("Unhandled node type: "+nt);

      }

  }

  boolean isHTMLElement(Node node, String name)

  {

    if (node.getNodeType() != Node.ELEMENT_NODE)

      return false;

    String localName = node.getLocalName();

    if (localName == null)

      localName = node.getNodeName();

    if (!name.equalsIgnoreCase(localName))

      return false;

    String uri = node.getNamespaceURI();

    return (uri == null || HTML_URIS.contains(uri));

  }

  boolean isDefined(String uri, String prefix)

  {

    if (XMLConstants.XML_NS_URI.equals(uri))

      return "xml".equals(prefix);

    if (XMLConstants.XMLNS_ATTRIBUTE_NS_URI.equals(uri))

      return "xmlns".equals(prefix);

    if (prefix == null)

      prefix = "";

    for (Iterator i = namespaces.iterator(); i.hasNext(); )

      {

        Map ctx = (Map) i.next();

        String val = (String) ctx.get(uri);

        if (val != null && val.equals(prefix))

          return true;

      }

    return false;

  }

  void pushNamespaceContext()

  {

    namespaces.addFirst(new HashMap());

  }

  String define(String uri, String prefix)

  {

    if (namespaces.isEmpty())

      return prefix;

    HashMap ctx = (HashMap) namespaces.getFirst();

    while (ctx.containsValue(prefix))

      {

        // Fabricate new prefix

        prefix = prefix + "_";

      }

    ctx.put(uri, prefix);

    return prefix;

  }

  void popNamespaceContext()

  {

    namespaces.removeFirst();

  }

  final byte[] encodeText(String text)

    throws IOException

  {

    encoder.reset();

    boolean htmlNeedingEncoding =

      (mode == Stylesheet.OUTPUT_HTML && !htmlEncoded);

    if (!encoder.canEncode(text) || htmlNeedingEncoding)

      {

        // Check each character

        CPStringBuilder buf = new CPStringBuilder();

        int len = text.length();

        for (int i = 0; i < len; i++)

          {

            char c = text.charAt(i);

            if (!encoder.canEncode(c))