uri.java

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/* URI.java -- An URI class
   Copyright (C) 2002, 2004, 2005  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., 59 Temple Place, Suite 330, Boston, MA
02111-1307 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 java.net;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @author Ito Kazumitsu ([e-mail])
 * @author Dalibor Topic ([e-mail])
 * @author Michael Koch ([e-mail])
 * @since 1.4
 */
public final class URI implements Comparable, Serializable
{
  static final long serialVersionUID = -6052424284110960213L;

  /**
   * Regular expression for parsing URIs.
   *
   * Taken from RFC 2396, Appendix B.
   * This expression doesn't parse IPv6 addresses.
   */
  private static final String URI_REGEXP =
    "^(([^:/?#]+):)?((//([^/?#]*))?([^?#]*)(\\?([^#]*))?)?(#(.*))?";

  private static final String AUTHORITY_REGEXP =
    "^((([^?#]*)@)?([^?#:]*)(:([^?#]*)))?";

  /**
   * Valid characters (taken from rfc2396)
   */
  private static final String RFC2396_DIGIT = "0123456789";
  private static final String RFC2396_LOWALPHA = "abcdefghijklmnopqrstuvwxyz";
  private static final String RFC2396_UPALPHA = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  private static final String RFC2396_ALPHA =
    RFC2396_LOWALPHA + RFC2396_UPALPHA;
  private static final String RFC2396_ALPHANUM = RFC2396_DIGIT + RFC2396_ALPHA;
  private static final String RFC2396_MARK = "-_.!~*'()";
  private static final String RFC2396_UNRESERVED =
    RFC2396_ALPHANUM + RFC2396_MARK;
  private static final String RFC2396_REG_NAME =
    RFC2396_UNRESERVED + "$,;:@&=+";
  private static final String RFC2396_PCHAR = RFC2396_UNRESERVED + ":@&=+$,";
  private static final String RFC2396_SEGMENT = RFC2396_PCHAR + ";";
  private static final String RFC2396_PATH_SEGMENTS = RFC2396_SEGMENT + "/";

  /**
   * Index of scheme component in parsed URI.
   */
  private static final int SCHEME_GROUP = 2;

  /**
   * Index of scheme-specific-part in parsed URI.
   */
  private static final int SCHEME_SPEC_PART_GROUP = 3;

  /**
   * Index of authority component in parsed URI.
   */
  private static final int AUTHORITY_GROUP = 5;

  /**
   * Index of path component in parsed URI.
   */
  private static final int PATH_GROUP = 6;

  /**
   * Index of query component in parsed URI.
   */
  private static final int QUERY_GROUP = 8;

  /**
   * Index of fragment component in parsed URI.
   */
  private static final int FRAGMENT_GROUP = 10;
  
  private static final int AUTHORITY_USERINFO_GROUP = 3;
  private static final int AUTHORITY_HOST_GROUP = 4;
  private static final int AUTHORITY_PORT_GROUP = 6;
  
  private transient String scheme;
  private transient String rawSchemeSpecificPart;
  private transient String schemeSpecificPart;
  private transient String rawAuthority;
  private transient String authority;
  private transient String rawUserInfo;
  private transient String userInfo;
  private transient String rawHost;
  private transient String host;
  private transient int port = -1;
  private transient String rawPath;
  private transient String path;
  private transient String rawQuery;
  private transient String query;
  private transient String rawFragment;
  private transient String fragment;
  private String string;

  private void readObject(ObjectInputStream is)
    throws ClassNotFoundException, IOException
  {
    this.string = (String) is.readObject();
    try
      {
	parseURI(this.string);
      }
    catch (URISyntaxException x)
      {
	// Should not happen.
	throw new RuntimeException(x);
      }
  }

  private void writeObject(ObjectOutputStream os) throws IOException
  {
    if (string == null)
      string = toString(); 
    os.writeObject(string);
  }

  private static String getURIGroup(Matcher match, int group)
  {
    String matched = match.group(group);
    return matched.length() == 0 ? null : matched;
  }

  /**
   * Sets fields of this URI by parsing the given string.
   *
   * @param str The string to parse
   *
   * @exception URISyntaxException If the given string violates RFC 2396
   */
  private void parseURI(String str) throws URISyntaxException
  {
    Pattern pattern = Pattern.compile(URI_REGEXP);
    Matcher matcher = pattern.matcher(str);
    
    if (matcher.matches())
      {
	scheme = getURIGroup(matcher, SCHEME_GROUP);
	rawSchemeSpecificPart = getURIGroup(matcher, SCHEME_SPEC_PART_GROUP);
	rawAuthority = getURIGroup(matcher, AUTHORITY_GROUP);
	rawPath = getURIGroup(matcher, PATH_GROUP);
	rawQuery = getURIGroup(matcher, QUERY_GROUP);
	rawFragment = getURIGroup(matcher, FRAGMENT_GROUP);
      }
    else
      throw new URISyntaxException(str, "doesn't match URI regular expression");

    if (rawAuthority != null)
      {
	pattern = Pattern.compile(AUTHORITY_REGEXP);
	matcher = pattern.matcher(rawAuthority);

	if (matcher.matches())
	  {
	    rawUserInfo = getURIGroup(matcher, AUTHORITY_USERINFO_GROUP);
	    rawHost = getURIGroup(matcher, AUTHORITY_HOST_GROUP);

	    String portStr = getURIGroup(matcher, AUTHORITY_PORT_GROUP);

	    if (portStr != null)
	      try
		{
		  port = Integer.parseInt(portStr);
		}
	      catch (NumberFormatException e)
		{
		  URISyntaxException use =
		    new URISyntaxException
		      (str, "doesn't match URI regular expression");
		  use.initCause(e);
		  throw use;
		}
	  }
	else
	  throw new URISyntaxException(str, "doesn't match URI regular expression");
      }

    // We must eagerly unquote the parts, because this is the only time
    // we may throw an exception.
    schemeSpecificPart = unquote(rawSchemeSpecificPart);
    authority = unquote(rawAuthority);
    userInfo = unquote(rawUserInfo);
    host = unquote(rawHost);
    path = unquote(rawPath);
    query = unquote(rawQuery);
    fragment = unquote(rawFragment);
  }

  /**
   * Unquote "%" + hex quotes characters
   *
   * @param str The string to unquote or null.
   *
   * @return The unquoted string or null if str was null.
   *
   * @exception URISyntaxException If the given string contains invalid
   * escape sequences.
   */
  private static String unquote(String str) throws URISyntaxException
  {
    if (str == null)
      return null;
    byte[] buf = new byte[str.length()];
    int pos = 0;
    for (int i = 0; i < str.length(); i++)
      {
	char c = str.charAt(i);
	if (c > 127)
	  throw new URISyntaxException(str, "Invalid character");
	if (c == '%')
	  {
	    if (i + 2 >= str.length())
	      throw new URISyntaxException(str, "Invalid quoted character");
	    int hi = Character.digit(str.charAt(++i), 16);
	    int lo = Character.digit(str.charAt(++i), 16);
	    if (lo < 0 || hi < 0)
	      throw new URISyntaxException(str, "Invalid quoted character");
	    buf[pos++] = (byte) (hi * 16 + lo);
	  }
	else
	  buf[pos++] = (byte) c;
      }
    try
      {
	return new String(buf, 0, pos, "utf-8");
      }
    catch (java.io.UnsupportedEncodingException x2)
      {
	throw (Error) new InternalError().initCause(x2);
      }
  }

  /**
   * Quote characters illegal in URIs in given string.
   *
   * Replace illegal characters by encoding their UTF-8
   * representation as "%" + hex code for each resulting
   * UTF-8 character.
   *
   * @param str The string to quote
   *
   * @return The quoted string.
   */
  private static String quote(String str)
  {
    // FIXME: unimplemented.
    return str;
  }

  /**
   * Quote characters illegal in URI authorities in given string.
   *
   * Replace illegal characters by encoding their UTF-8
   * representation as "%" + hex code for each resulting
   * UTF-8 character.
   *
   * @param str The string to quote
   *
   * @return The quoted string.
   */
  private static String quoteAuthority(String str)
  {
    // Technically, we should be using RFC2396_AUTHORITY, but
    // it contains no additional characters.
    return quote(str, RFC2396_REG_NAME);
  }

  /**
   * Quote characters in str that are not part of legalCharacters.
   *
   * Replace illegal characters by encoding their UTF-8
   * representation as "%" + hex code for each resulting
   * UTF-8 character.
   *
   * @param str The string to quote
   * @param legalCharacters The set of legal characters
   *
   * @return The quoted string.
   */
  private static String quote(String str, String legalCharacters)
  {
    StringBuffer sb = new StringBuffer(str.length());
    for (int i = 0; i < str.length(); i++)
      {
	char c = str.charAt(i);
	if (legalCharacters.indexOf(c) == -1)
	  {
	    String hex = "0123456789ABCDEF";
	    if (c <= 127)
	      sb.append('%').append(hex.charAt(c / 16)).append(hex.charAt(c % 16));
	    else
	      {
		try
		  {
		    // this is far from optimal, but it works
		    byte[] utf8 = str.substring(i, i + 1).getBytes("utf-8");
		    for (int j = 0; j < utf8.length; j++)
		      sb.append('%').append(hex.charAt((utf8[j] & 0xff) / 16))
		        .append(hex.charAt((utf8[j] & 0xff) % 16));
		  }
		catch (java.io.UnsupportedEncodingException x)
		  {
		    throw (Error) new InternalError().initCause(x);
		  }
	      }
	  }
	else
	  sb.append(c);
      }
    return sb.toString();
  }

  /**
   * Quote characters illegal in URI hosts in given string.
   *
   * Replace illegal characters by encoding their UTF-8
   * representation as "%" + hex code for each resulting
   * UTF-8 character.
   *
   * @param str The string to quote
   *
   * @return The quoted string.
   */
  private static String quoteHost(String str)
  {
    // FIXME: unimplemented.
    return str;
  }

  /**
   * Quote characters illegal in URI paths in given string.
   *
   * Replace illegal characters by encoding their UTF-8
   * representation as "%" + hex code for each resulting
   * UTF-8 character.
   *
   * @param str The string to quote
   *
   * @return The quoted string.
   */
  private static String quotePath(String str)
  {
    // Technically, we should be using RFC2396_PATH, but
    // it contains no additional characters.
    return quote(str, RFC2396_PATH_SEGMENTS);
  }

  /**
   * Quote characters illegal in URI user infos in given string.
   *
   * Replace illegal characters by encoding their UTF-8
   * representation as "%" + hex code for each resulting
   * UTF-8 character.
   *
   * @param str The string to quote
   *
   * @return The quoted string.
   */
  private static String quoteUserInfo(String str)
  {
    // FIXME: unimplemented.
    return str;
  }

  /**
   * Creates an URI from the given string
   *
   * @param str The string to create the URI from
   *
   * @exception URISyntaxException If the given string violates RFC 2396
   * @exception NullPointerException If str is null
   */
  public URI(String str) throws URISyntaxException
  {