001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 *
019 */
020package org.apache.directory.api.ldap.codec.api;
021
022
023import java.io.InputStream;
024import java.nio.ByteBuffer;
025
026import org.apache.directory.api.asn1.DecoderException;
027import org.apache.directory.api.asn1.ber.Asn1Decoder;
028import org.apache.directory.api.asn1.ber.tlv.TLVStateEnum;
029import org.apache.directory.api.i18n.I18n;
030import org.apache.directory.api.ldap.model.message.Message;
031import org.slf4j.Logger;
032import org.slf4j.LoggerFactory;
033
034
035/**
036 * The LdapDecoder decodes ASN.1 BER encoded PDUs into LDAP messages
037 *
038 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
039 */
040public class LdapDecoder
041{
042    /** The logger */
043    private static final Logger LOG = LoggerFactory.getLogger( LdapDecoder.class );
044
045    /** A speedup for logger */
046    private static final boolean IS_DEBUG = LOG.isDebugEnabled();
047
048    /** The ASN 1 decoder instance */
049    private Asn1Decoder asn1Decoder;
050
051    /** The name of the LdapSession's attribute for the LDAP container used during the decoding */
052    public static final String MESSAGE_CONTAINER_ATTR = "LDAP-container";
053
054    /** The maximum PDU size, stored into the LDAPSession's attribute */
055    public static final String MAX_PDU_SIZE_ATTR = "LDAP-maxPduSize";
056
057
058    /**
059     * Creates an instance of a Ldap Decoder implementation.
060     */
061    public LdapDecoder()
062    {
063        asn1Decoder = new Asn1Decoder();
064    }
065
066
067    /**
068     * Decodes a PDU from an input stream into a Ldap message container. We can only
069     * decode one complete message.
070     *
071     * @param in The input stream to read and decode PDU bytes from
072     * @param container The LdapMessageContainer containing the message to decode
073     * @return return The decoded message
074     * @throws DecoderException If the decoding failed
075     */
076    public Message decode( InputStream in, LdapMessageContainer<MessageDecorator<? extends Message>> container )
077        throws DecoderException
078    {
079        try
080        {
081            int amount;
082
083            while ( in.available() > 0 )
084            {
085                byte[] buf = new byte[in.available()];
086
087                amount = in.read( buf );
088                if ( amount == -1 )
089                {
090                    break;
091                }
092
093                asn1Decoder.decode( ByteBuffer.wrap( buf, 0, amount ), container );
094            }
095        }
096        catch ( Exception e )
097        {
098            String message = I18n.err( I18n.ERR_04060, e.getLocalizedMessage() );
099            LOG.error( message );
100            throw new DecoderException( message, e );
101        }
102
103        if ( container.getState() == TLVStateEnum.PDU_DECODED )
104        {
105            if ( IS_DEBUG )
106            {
107                LOG.debug( "Decoded LdapMessage : " + container );
108            }
109
110            return container.getMessage();
111        }
112        else
113        {
114            LOG.error( I18n.err( I18n.ERR_04062 ) );
115            throw new DecoderException( I18n.err( I18n.ERR_04063 ) );
116        }
117    }
118}