content: /*
   * Copyright 1999-2012 Alibaba Group.
   *  
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *  
   *      http://www.apache.org/licenses/LICENSE-2.0
   *  
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.alibaba.cobar.jdbc.packet;
  
  import java.io.IOException;
  import java.io.OutputStream;
  
  import com.alibaba.cobar.jdbc.Driver;
  import com.alibaba.cobar.jdbc.util.ByteUtil;
  import com.alibaba.cobar.jdbc.util.StreamUtil;
  
  /**
   * From client to server during initial handshake.
   * 
   * <pre>
   * Bytes                        Name
   * -----                        ----
   * 4                            client_flags
   * 4                            max_packet_size
   * 1                            charset_number
   * 23                           (filler) always 0x00...
   * n (Null-Terminated String)   user
   * n (Length Coded Binary)      scramble_buff (1 + x bytes)
   * n (Null-Terminated String)   databasename (optional)
   * 
   * @see http://forge.mysql.com/wiki/MySQL_Internals_ClientServer_Protocol#Client_Authentication_Packet
   * </pre>
   * 
   * @author xianmao.hexm 2010-7-15 下午04:35:34
   */
  public class AuthPacket extends MySQLPacket {
  
      private static final byte[] FILLER = new byte[23];
      static {
          byte[] version = Driver.VERSION.getBytes();
          byte[] header = ByteUtil.getBytesWithLength(version.length);
          if ((header.length + version.length) <= FILLER.length) {
              int index = 0;
              for (int i = 0; i < header.length; i++) {
                  FILLER[index++] = header[i];
              }
              for (int i = 0; i < version.length; i++) {
                  FILLER[index++] = version[i];
              }
          }
      }
  
      public long clientFlags;
      public long maxPacketSize;
      public int charsetIndex;
      public String user;
      public byte[] password;
      public String database;
  
      public void write(OutputStream out) throws IOException {
          StreamUtil.writeUB3(out, getPacketLength());
          StreamUtil.write(out, packetId);
          StreamUtil.writeUB4(out, clientFlags);
          StreamUtil.writeUB4(out, maxPacketSize);
          StreamUtil.write(out, (byte) charsetIndex);
          out.write(FILLER);
          if (user == null) {
              StreamUtil.write(out, (byte) 0);
          } else {
              StreamUtil.writeWithNull(out, user.getBytes());
          }
          if (password == null) {
              StreamUtil.write(out, (byte) 0);
          } else {
              StreamUtil.writeWithLength(out, password);
          }
          if (database == null) {
              StreamUtil.write(out, (byte) 0);
          } else {
              StreamUtil.writeWithNull(out, database.getBytes());
          }
      }
  
      protected int getPacketLength() {
          int size = 32;// 4+4+1+23;
          size += (user == null) ? 1 : user.length() + 1;
          size += (password == null) ? 1 : ByteUtil.getLengthWithBytes(password);
          size += (database == null) ? 1 : database.length() + 1;
          return size;
      }
  
      @Override
      protected String packetInfo() {
          return "MySQL Authentication Packet";
      }
  
  }
  