/*
 * Copyright 2000-2006 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package javax.security.auth.x500;

import java.io.*;
import java.security.Principal;
import java.util.Collections;
import java.util.Map;
import sun.security.x509.X500Name;
import sun.security.util.*;

/**
 * <p> This class represents an X.500 <code>Principal</code>.
 * <code>X500Principal</code>s are represented by distinguished names such as
 * "CN=Duke, OU=JavaSoft, O=Sun Microsystems, C=US".
 *
 * <p> This class can be instantiated by using a string representation
 * of the distinguished name, or by using the ASN.1 DER encoded byte
 * representation of the distinguished name.  The current specification
 * for the string representation of a distinguished name is defined in
 * <a href="http://www.ietf.org/rfc/rfc2253.txt">RFC 2253: Lightweight
 * Directory Access Protocol (v3): UTF-8 String Representation of
 * Distinguished Names</a>. This class, however, accepts string formats from
 * both RFC 2253 and <a href="http://www.ietf.org/rfc/rfc1779.txt">RFC 1779:
 * A String Representation of Distinguished Names</a>, and also recognizes
 * attribute type keywords whose OIDs (Object Identifiers) are defined in
 * <a href="http://www.ietf.org/rfc/rfc3280.txt">RFC 3280: Internet X.509
 * Public Key Infrastructure Certificate and CRL Profile</a>.
 *
 * <p> The string representation for this <code>X500Principal</code>
 * can be obtained by calling the <code>getName</code> methods.
 *
 * <p> Note that the <code>getSubjectX500Principal</code> and
 * <code>getIssuerX500Principal</code> methods of
 * <code>X509Certificate</code> return X500Principals representing the
 * issuer and subject fields of the certificate.
 *
 * @see java.security.cert.X509Certificate
 * @since 1.4
 */
public final class X500Principal implements Principal, java.io.Serializable {

    private static final long serialVersionUID = -500463348111345721L;

    /**
     * RFC 1779 String format of Distinguished Names.
     */
    public static final String RFC1779 = "RFC1779";
    /**
     * RFC 2253 String format of Distinguished Names.
     */
    public static final String RFC2253 = "RFC2253";
    /**
     * Canonical String format of Distinguished Names.
     */
    public static final String CANONICAL = "CANONICAL";

    /**
     * The X500Name representing this principal.
     *
     * NOTE: this field is reflectively accessed from within X500Name.
     */
    private transient X500Name thisX500Name;

    /**
     * Creates an X500Principal by wrapping an X500Name.
     *
     * NOTE: The constructor is package private. It is intended to be accessed
     * using privileged reflection from classes in sun.security.*.
     * Currently referenced from sun.security.x509.X500Name.asX500Principal().
     */
    X500Principal(X500Name x500Name) {
        thisX500Name = x500Name;
    }

    /**
     * Creates an <code>X500Principal</code> from a string representation of
     * an X.500 distinguished name (ex:
     * "CN=Duke, OU=JavaSoft, O=Sun Microsystems, C=US").
     * The distinguished name must be specified using the grammar defined in
     * RFC 1779 or RFC 2253 (either format is acceptable).
     *
     * <p>This constructor recognizes the attribute type keywords
     * defined in RFC 1779 and RFC 2253
     * (and listed in {@link #getName(String format) getName(String format)}),
     * as well as the T, DNQ or DNQUALIFIER, SURNAME, GIVENNAME, INITIALS,
     * GENERATION, EMAILADDRESS, and SERIALNUMBER keywords whose OIDs are
     * defined in RFC 3280 and its successor.
     * Any other attribute type must be specified as an OID.
     *
     * @param name an X.500 distinguished name in RFC 1779 or RFC 2253 format
     * @exception NullPointerException if the <code>name</code>
     *                  is <code>null</code>
     * @exception IllegalArgumentException if the <code>name</code>
     *                  is improperly specified
     */
    public X500Principal(String name) {
        this(name, (Map<String, String>) Collections.EMPTY_MAP);
    }

    /**
     * Creates an <code>X500Principal</code> from a string representation of
     * an X.500 distinguished name (ex:
     * "CN=Duke, OU=JavaSoft, O=Sun Microsystems, C=US").
     * The distinguished name must be specified using the grammar defined in
     * RFC 1779 or RFC 2253 (either format is acceptable).
     *
     * <p> This constructor recognizes the attribute type keywords specified
     * in {@link #X500Principal(String)} and also recognizes additional
     * keywords that have entries in the <code>keywordMap</code> parameter.
     * Keyword entries in the keywordMap take precedence over the default
     * keywords recognized by <code>X500Principal(String)</code>. Keywords
     * MUST be specified in all upper-case, otherwise they will be ignored.
     * Improperly specified keywords are ignored; however if a keyword in the
     * name maps to an improperly specified OID, an
     * <code>IllegalArgumentException</code> is thrown. It is permissible to
     * have 2 different keywords that map to the same OID.
     *
     * @param name an X.500 distinguished name in RFC 1779 or RFC 2253 format
     * @param keywordMap an attribute type keyword map, where each key is a
     *   keyword String that maps to a corresponding object identifier in String
     *   form (a sequence of nonnegative integers separated by periods). The map
     *   may be empty but never <code>null</code>.
     * @exception NullPointerException if <code>name</code> or
     *   <code>keywordMap</code> is <code>null</code>
     * @exception IllegalArgumentException if the <code>name</code> is
     *   improperly specified or a keyword in the <code>name</code> maps to an
     *   OID that is not in the correct form
     * @since 1.6
     */
    public X500Principal(String name, Map<String, String> keywordMap) {
        if (name == null) {
            throw new NullPointerException
                (sun.security.util.ResourcesMgr.getString
                ("provided null name"));
        }
        if (keywordMap == null) {
            throw new NullPointerException
                (sun.security.util.ResourcesMgr.getString
                ("provided null keyword map"));
        }

        try {
            thisX500Name = new X500Name(name, keywordMap);
        } catch (Exception e) {
            IllegalArgumentException iae = new IllegalArgumentException
                        ("improperly specified input name: " + name);
            iae.initCause(e);
            throw iae;
        }
    }

    /**
     * Creates an <code>X500Principal</code> from a distinguished name in
     * ASN.1 DER encoded form. The ASN.1 notation for this structure is as
     * follows.
     * <pre><code>
     * Name ::= CHOICE {
     *   RDNSequence }
     *
     * RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
     *
     * RelativeDistinguishedName ::=
     *   SET SIZE (1 .. MAX) OF AttributeTypeAndValue
     *
     * AttributeTypeAndValue ::= SEQUENCE {
     *   type     AttributeType,
     *   value    AttributeValue }
     *
     * AttributeType ::= OBJECT IDENTIFIER
     *
     * AttributeValue ::= ANY DEFINED BY AttributeType
     * ....
     * DirectoryString ::= CHOICE {
     *       teletexString           TeletexString (SIZE (1..MAX)),
     *       printableString         PrintableString (SIZE (1..MAX)),
     *       universalString         UniversalString (SIZE (1..MAX)),
     *       utf8String              UTF8String (SIZE (1.. MAX)),
     *       bmpString               BMPString (SIZE (1..MAX)) }
     * </code></pre>
     *
     * @param name a byte array containing the distinguished name in ASN.1
     * DER encoded form
     * @throws IllegalArgumentException if an encoding error occurs
     *          (incorrect form for DN)
     */
    public X500Principal(byte[] name) {
        try {
            thisX500Name = new X500Name(name);
        } catch (Exception e) {
            IllegalArgumentException iae = new IllegalArgumentException
                        ("improperly specified input name");
            iae.initCause(e);
            throw iae;
        }
    }

    /**
     * Creates an <code>X500Principal</code> from an <code>InputStream</code>
     * containing the distinguished name in ASN.1 DER encoded form.
     * The ASN.1 notation for this structure is supplied in the
     * documentation for
     * {@link #X500Principal(byte[] name) X500Principal(byte[] name)}.
     *
     * <p> The read position of the input stream is positioned
     * to the next available byte after the encoded distinguished name.
     *
     * @param is an <code>InputStream</code> containing the distinguished
     *          name in ASN.1 DER encoded form
     *
     * @exception NullPointerException if the <code>InputStream</code>
     *          is <code>null</code>
     * @exception IllegalArgumentException if an encoding error occurs
     *          (incorrect form for DN)
     */
    public X500Principal(InputStream is) {
        if (is == null) {
            throw new NullPointerException("provided null input stream");
        }

        try {
            if (is.markSupported())
                is.mark(is.available() + 1);
            DerValue der = new DerValue(is);
            thisX500Name = new X500Name(der.data);
        } catch (Exception e) {
            if (is.markSupported()) {
                try {
                    is.reset();
                } catch (IOException ioe) {
                    IllegalArgumentException iae = new IllegalArgumentException
                        ("improperly specified input stream " +
                        ("and unable to reset input stream"));
                    iae.initCause(e);
                    throw iae;
                }
            }
            IllegalArgumentException iae = new IllegalArgumentException
                        ("improperly specified input stream");
            iae.initCause(e);
            throw iae;
        }
    }

    /**
     * Returns a string representation of the X.500 distinguished name using
     * the format defined in RFC 2253.
     *
     * <p>This method is equivalent to calling
     * <code>getName(X500Principal.RFC2253)</code>.
     *
     * @return the distinguished name of this <code>X500Principal</code>
     */
    public String getName() {
        return getName(X500Principal.RFC2253);
    }

    /**
     * Returns a string representation of the X.500 distinguished name
     * using the specified format. Valid values for the format are
     * "RFC1779", "RFC2253", and "CANONICAL" (case insensitive).
     *
     * <p> If "RFC1779" is specified as the format,
     * this method emits the attribute type keywords defined in
     * RFC 1779 (CN, L, ST, O, OU, C, STREET).
     * Any other attribute type is emitted as an OID.
     *
     * <p> If "RFC2253" is specified as the format,
     * this method emits the attribute type keywords defined in
     * RFC 2253 (CN, L, ST, O, OU, C, STREET, DC, UID).
     * Any other attribute type is emitted as an OID.
     * Under a strict reading, RFC 2253 only specifies a UTF-8 string
     * representation. The String returned by this method is the
     * Unicode string achieved by decoding this UTF-8 representation.
     *
     * <p> If "CANONICAL" is specified as the format,
     * this method returns an RFC 2253 conformant string representation
     * with the following additional canonicalizations:
     *
     * <p><ol>
     * <li> Leading zeros are removed from attribute types
     *          that are encoded as dotted decimal OIDs
     * <li> DirectoryString attribute values of type
     *          PrintableString and UTF8String are not
     *          output in hexadecimal format
     * <li> DirectoryString attribute values of types
     *          other than PrintableString and UTF8String
     *          are output in hexadecimal format
     * <li> Leading and trailing white space characters
     *          are removed from non-hexadecimal attribute values
     *          (unless the value consists entirely of white space characters)
     * <li> Internal substrings of one or more white space characters are
     *          converted to a single space in non-hexadecimal
     *          attribute values
     * <li> Relative Distinguished Names containing more than one
     *          Attribute Value Assertion (AVA) are output in the
     *          following order: an alphabetical ordering of AVAs
     *          containing standard keywords, followed by a numeric
     *          ordering of AVAs containing OID keywords.
     * <li> The only characters in attribute values that are escaped are
     *          those which section 2.4 of RFC 2253 states must be escaped
     *          (they are escaped using a preceding backslash character)
     * <li> The entire name is converted to upper case
     *          using <code>String.toUpperCase(Locale.US)</code>
     * <li> The entire name is converted to lower case
     *          using <code>String.toLowerCase(Locale.US)</code>
     * <li> The name is finally normalized using normalization form KD,
     *          as described in the Unicode Standard and UAX #15
     * </ol>
     *
     * <p> Additional standard formats may be introduced in the future.
     *
     * @param format the format to use
     *
     * @return a string representation of this <code>X500Principal</code>
     *          using the specified format
     * @throws IllegalArgumentException if the specified format is invalid
     *          or null
     */
    public String getName(String format) {
        if (format != null) {
            if (format.equalsIgnoreCase(RFC1779)) {
                return thisX500Name.getRFC1779Name();
            } else if (format.equalsIgnoreCase(RFC2253)) {
                return thisX500Name.getRFC2253Name();
            } else if (format.equalsIgnoreCase(CANONICAL)) {
                return thisX500Name.getRFC2253CanonicalName();
            }
        }
        throw new IllegalArgumentException("invalid format specified");
    }

    /**
     * Returns a string representation of the X.500 distinguished name
     * using the specified format. Valid values for the format are
     * "RFC1779" and "RFC2253" (case insensitive). "CANONICAL" is not
     * permitted and an <code>IllegalArgumentException</code> will be thrown.
     *
     * <p>This method returns Strings in the format as specified in
     * {@link #getName(String)} and also emits additional attribute type
     * keywords for OIDs that have entries in the <code>oidMap</code>
     * parameter. OID entries in the oidMap take precedence over the default
     * OIDs recognized by <code>getName(String)</code>.
     * Improperly specified OIDs are ignored; however if an OID
     * in the name maps to an improperly specified keyword, an
     * <code>IllegalArgumentException</code> is thrown.
     *
     * <p> Additional standard formats may be introduced in the future.
     *
     * <p> Warning: additional attribute type keywords may not be recognized
     * by other implementations; therefore do not use this method if
     * you are unsure if these keywords will be recognized by other
     * implementations.
     *
     * @param format the format to use
     * @param oidMap an OID map, where each key is an object identifier in
     *  String form (a sequence of nonnegative integers separated by periods)
     *  that maps to a corresponding attribute type keyword String.
     *  The map may be empty but never <code>null</code>.
     * @return a string representation of this <code>X500Principal</code>
     *          using the specified format
     * @throws IllegalArgumentException if the specified format is invalid,
     *  null, or an OID in the name maps to an improperly specified keyword
     * @throws NullPointerException if <code>oidMap</code> is <code>null</code>
     * @since 1.6
     */
    public String getName(String format, Map<String, String> oidMap) {
        if (oidMap == null) {
            throw new NullPointerException
                (sun.security.util.ResourcesMgr.getString
                ("provided null OID map"));
        }
        if (format != null) {
            if (format.equalsIgnoreCase(RFC1779)) {
                return thisX500Name.getRFC1779Name(oidMap);
            } else if (format.equalsIgnoreCase(RFC2253)) {
                return thisX500Name.getRFC2253Name(oidMap);
            }
        }
        throw new IllegalArgumentException("invalid format specified");
    }

    /**
     * Returns the distinguished name in ASN.1 DER encoded form. The ASN.1
     * notation for this structure is supplied in the documentation for
     * {@link #X500Principal(byte[] name) X500Principal(byte[] name)}.
     *
     * <p>Note that the byte array returned is cloned to protect against
     * subsequent modifications.
     *
     * @return a byte array containing the distinguished name in ASN.1 DER
     * encoded form
     */
    public byte[] getEncoded() {
        try {
            return thisX500Name.getEncoded();
        } catch (IOException e) {
            throw new RuntimeException("unable to get encoding", e);
        }
    }

    /**
     * Return a user-friendly string representation of this
     * <code>X500Principal</code>.
     *
     * @return a string representation of this <code>X500Principal</code>
     */
    public String toString() {
        return thisX500Name.toString();
    }

    /**
     * Compares the specified <code>Object</code> with this
     * <code>X500Principal</code> for equality.
     *
     * <p> Specifically, this method returns <code>true</code> if
     * the <code>Object</code> <i>o</i> is an <code>X500Principal</code>
     * and if the respective canonical string representations
     * (obtained via the <code>getName(X500Principal.CANONICAL)</code> method)
     * of this object and <i>o</i> are equal.
     *
     * <p> This implementation is compliant with the requirements of RFC 3280.
     *
     * @param o Object to be compared for equality with this
     *          <code>X500Principal</code>
     *
     * @return <code>true</code> if the specified <code>Object</code> is equal
     *          to this <code>X500Principal</code>, <code>false</code> otherwise
     */
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o instanceof X500Principal == false) {
            return false;
        }
        X500Principal other = (X500Principal)o;
        return this.thisX500Name.equals(other.thisX500Name);
    }

    /**
     * Return a hash code for this <code>X500Principal</code>.
     *
     * <p> The hash code is calculated via:
     * <code>getName(X500Principal.CANONICAL).hashCode()</code>
     *
     * @return a hash code for this <code>X500Principal</code>
     */
    public int hashCode() {
        return thisX500Name.hashCode();
    }

    /**
     * Save the X500Principal object to a stream.
     *
     * @serialData this <code>X500Principal</code> is serialized
     *          by writing out its DER-encoded form
     *          (the value of <code>getEncoded</code> is serialized).
     */
    private void writeObject(java.io.ObjectOutputStream s)
        throws IOException {
        s.writeObject(thisX500Name.getEncodedInternal());
    }

    /**
     * Reads this object from a stream (i.e., deserializes it).
     */
    private void readObject(java.io.ObjectInputStream s)
        throws java.io.IOException,
               java.io.NotActiveException,
               ClassNotFoundException {

        // re-create thisX500Name
        thisX500Name = new X500Name((byte[])s.readObject());
    }
}