jid.java

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/**
 * Copyright (C) 2004-2007 Jive Software. All rights reserved.
 *
 * This software is published under the terms of the GNU Public License (GPL),
 * a copy of which is included in this distribution, or a commercial license
 * agreement with Jive.
 */

package org.xmpp.packet;

import org.jivesoftware.stringprep.IDNA;
import org.jivesoftware.stringprep.Stringprep;
import org.jivesoftware.stringprep.StringprepException;
import org.jivesoftware.util.cache.ExternalizableUtil;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * An XMPP address (JID). A JID is made up of a node (generally a username), a domain,
 * and a resource. The node and resource are optional; domain is required. In simple
 * ABNF form:
 *
 * <ul><tt>jid = [ node "@" ] domain [ "/" resource ]</tt></ul>
 *
 * Some sample JID's:
 * <ul>
 *      <li><tt>[e-mail]</tt></li>
 *      <li><tt>[e-mail]/home</tt></li>
 *      <li><tt>example.com</tt></li>
 * </ul>
 *
 * Each allowable portion of a JID (node, domain, and resource) must not be more
 * than 1023 bytes in length, resulting in a maximum total size (including the '@'
 * and '/' separators) of 3071 bytes.
 *
 * @author Matt Tucker
 */
public class JID implements Comparable<JID>, Externalizable {

    // Stringprep operations are very expensive. Therefore, we cache node, domain and
    // resource values that have already had stringprep applied so that we can check
    // incoming values against the cache.
    private static Map<String,Object> stringprepCache = Collections.synchronizedMap(new Cache(10000));

    private String node;
    private String domain;
    private String resource;

    private String cachedFullJID;
    private String cachedBareJID;

    /**
     * Escapes the node portion of a JID according to "JID Escaping" (JEP-0106).
     * Escaping replaces characters prohibited by node-prep with escape sequences,
     * as follows:<p>
     *
     * <table border="1">
     * <tr><td><b>Unescaped Character</b></td><td><b>Encoded Sequence</b></td></tr>
     * <tr><td>&lt;space&gt;</td><td>\20</td></tr>
     * <tr><td>"</td><td>\22</td></tr>
     * <tr><td>&</td><td>\26</td></tr>
     * <tr><td>'</td><td>\27</td></tr>
     * <tr><td>/</td><td>\2f</td></tr>
     * <tr><td>:</td><td>\3a</td></tr>
     * <tr><td>&lt;</td><td>\3c</td></tr>
     * <tr><td>&gt;</td><td>\3e</td></tr>
     * <tr><td>@</td><td>\40</td></tr>
     * <tr><td>\</td><td>\5c</td></tr>
     * </table><p>
     *
     * This process is useful when the node comes from an external source that doesn't
     * conform to nodeprep. For example, a username in LDAP may be "Joe Smith". Because
     * the &lt;space&gt; character isn't a valid part of a node, the username should
     * be escaped to "Joe\20Smith" before being made into a JID (e.g. "joe\[e-mail]"
     * after case-folding, etc. has been applied).<p>
     *
     * All node escaping and un-escaping must be performed manually at the appropriate
     * time; the JID class will not escape or un-escape automatically.
     *
     * @param node the node.
     * @return the escaped version of the node.
     */
    public static String escapeNode(String node) {
        if (node == null) {
            return null;
        }
        StringBuilder buf = new StringBuilder(node.length() + 8);
        for (int i=0, n=node.length(); i<n; i++) {
            char c = node.charAt(i);
            switch (c) {
                case '"': buf.append("\\22"); break;
                case '&': buf.append("\\26"); break;
                case '\'': buf.append("\\27"); break;
                case '/': buf.append("\\2f"); break;
                case ':': buf.append("\\3a"); break;
                case '<': buf.append("\\3c"); break;
                case '>': buf.append("\\3e"); break;
                case '@': buf.append("\\40"); break;
                case '\\': buf.append("\\5c"); break;
                default: {
                    if (Character.isWhitespace(c)) {
                        buf.append("\\20");
                    }
                    else {
                        buf.append(c);
                    }
                }
            }
        }
        return buf.toString();
    }

    /**
     * Un-escapes the node portion of a JID according to "JID Escaping" (JEP-0106).<p>
     * Escaping replaces characters prohibited by node-prep with escape sequences,
     * as follows:<p>
     *
     * <table border="1">
     * <tr><td><b>Unescaped Character</b></td><td><b>Encoded Sequence</b></td></tr>
     * <tr><td>&lt;space&gt;</td><td>\20</td></tr>
     * <tr><td>"</td><td>\22</td></tr>
     * <tr><td>&</td><td>\26</td></tr>
     * <tr><td>'</td><td>\27</td></tr>
     * <tr><td>/</td><td>\2f</td></tr>
     * <tr><td>:</td><td>\3a</td></tr>
     * <tr><td>&lt;</td><td>\3c</td></tr>
     * <tr><td>&gt;</td><td>\3e</td></tr>
     * <tr><td>@</td><td>\40</td></tr>
     * <tr><td>\</td><td>\5c</td></tr>
     * </table><p>
     *
     * This process is useful when the node comes from an external source that doesn't
     * conform to nodeprep. For example, a username in LDAP may be "Joe Smith". Because
     * the &lt;space&gt; character isn't a valid part of a node, the username should
     * be escaped to "Joe\20Smith" before being made into a JID (e.g. "joe\[e-mail]"
     * after case-folding, etc. has been applied).<p>
     *
     * All node escaping and un-escaping must be performed manually at the appropriate
     * time; the JID class will not escape or un-escape automatically.
     *
     * @param node the escaped version of the node.
     * @return the un-escaped version of the node.
     */
    public static String unescapeNode(String node) {
        if (node == null) {
            return null;
        }
        char [] nodeChars = node.toCharArray();
        StringBuilder buf = new StringBuilder(nodeChars.length);
        for (int i=0, n=nodeChars.length; i<n; i++) {
            compare: {
                char c = node.charAt(i);
                if (c == '\\' && i+2<n) {
                    char c2 = nodeChars[i+1];
                    char c3 = nodeChars[i+2];
                    if (c2 == '2') {
                        switch (c3) {
                            case '0': buf.append(' '); i+=2; break compare;
                            case '2': buf.append('"'); i+=2; break compare;
                            case '6': buf.append('&'); i+=2; break compare;
                            case '7': buf.append('\''); i+=2; break compare;
                            case 'f': buf.append('/'); i+=2; break compare;
                        }
                    }
                    else if (c2 == '3') {
                        switch (c3) {
                            case 'a': buf.append(':'); i+=2; break compare;
                            case 'c': buf.append('<'); i+=2; break compare;
                            case 'e': buf.append('>'); i+=2; break compare;
                        }
                    }
                    else if (c2 == '4') {
                        if (c3 == '0') {
                            buf.append("@");
                            i+=2;
                            break compare;
                        }
                    }
                    else if (c2 == '5') {
                        if (c3 == 'c') {
                            buf.append("\\");
                            i+=2;
                            break compare;
                        }
                    }
                }
                buf.append(c);
            }
        }
        return buf.toString();
    }

    public static String resourceprep(String resource) throws StringprepException {
        String answer = resource;
        if (!stringprepCache.containsKey(resource)) {
            answer = Stringprep.resourceprep(resource);
            // Validate field is not greater than 1023 bytes. UTF-8 characters use two bytes.
            if (answer != null && answer.length()*2 > 1023) {
                return answer;
            }
            stringprepCache.put(answer, null);
        }
        return answer;
    }

    /**
     * Constructor added for Externalizable. Do not use this constructor.
     */
    public JID() {
    }

    /**
     * Constructs a JID from it's String representation.
     *
     * @param jid a valid JID.
     * @throws IllegalArgumentException if the JID is not valid.
     */
    public JID(String jid) {
        if (jid == null) {
            throw new NullPointerException("JID cannot be null");
        }
        String[] parts = getParts(jid);

        init(parts[0], parts[1], parts[2]);
    }

    /**
     * Constructs a JID given a node, domain, and resource.
     *
     * @param node the node.
     * @param domain the domain, which must not be <tt>null</tt>.
     * @param resource the resource.
     * @throws IllegalArgumentException if the JID is not valid.
     */
    public JID(String node, String domain, String resource) {
        if (domain == null) {
            throw new NullPointerException("Domain cannot be null");
        }
        init(node, domain, resource);
    }

    /**
     * Constructs a JID given a node, domain, and resource being able to specify if stringprep
     * should be applied or not.
     *
     * @param node the node.
     * @param domain the domain, which must not be <tt>null</tt>.
     * @param resource the resource.
     * @param skipStringprep true if stringprep should not be applied.
     * @throws IllegalArgumentException if the JID is not valid.
     */
    public JID(String node, String domain, String resource, boolean skipStringprep) {
        if (domain == null) {
            throw new NullPointerException("Domain cannot be null");
        }
        if (skipStringprep) {
            this.node = node;
            this.domain = domain;
            this.resource = resource;
            // Cache the bare and full JID String representation
            updateCache();
        }
        else {
            init(node, domain, resource);
        }
    }

    /**
     * Returns a String array with the parsed node, domain and resource.
     * No Stringprep is performed while parsing the textual representation.
     *
     * @param jid the textual JID representation.
     * @return a string array with the parsed node, domain and resource.
     */
    static String[] getParts(String jid) {
        String[] parts = new String[3];
        String node = null , domain, resource;
        if (jid == null) {
            return parts;
        }