package org.apache.maven.surefire.booter;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  
  import java.io.DataInputStream;
  import java.io.IOException;
  
  import static java.nio.charset.StandardCharsets.US_ASCII;
  import static java.util.Objects.requireNonNull;
  import static java.lang.String.format;
  
  /**
   * Commands which are sent from plugin to the forked jvm.
   * Support and methods related to the commands.
   *
   * @author <a href="mailto:tibordigana@apache.org">Tibor Digana (tibor17)</a>
   * @since 2.19
   */
  public enum MasterProcessCommand
  {
      RUN_CLASS( 0, String.class ),
      TEST_SET_FINISHED( 1, Void.class ),
      SKIP_SINCE_NEXT_TEST( 2, Void.class ),
      SHUTDOWN( 3, String.class ),
  
      /** To tell a forked process that the master process is still alive. Repeated after 10 seconds. */
      NOOP( 4, Void.class ),
      BYE_ACK( 5, Void.class );
  
      private final int id;
  
      private final Class<?> dataType;
  
      MasterProcessCommand( int id, Class<?> dataType )
      {
          this.id = id;
          this.dataType = requireNonNull( dataType, "dataType cannot be null" );
      }
  
      public int getId()
      {
          return id;
      }
  
      public Class<?> getDataType()
      {
          return dataType;
      }
  
      public boolean hasDataType()
      {
          return dataType != Void.class;
      }
  
      @SuppressWarnings( "checkstyle:magicnumber" )
      public byte[] encode( String data )
      {
          if ( !hasDataType() )
          {
              throw new IllegalArgumentException( "cannot use data without data type" );
          }
  
          if ( getDataType() != String.class )
          {
              throw new IllegalArgumentException( "Data type can be only " + String.class );
          }
  
          final byte[] dataBytes = fromDataType( data );
          final int len = dataBytes.length;
  
          final byte[] encoded = new byte[8 + len];
  
          final int command = getId();
          setCommandAndDataLength( command, len, encoded );
          System.arraycopy( dataBytes, 0, encoded, 8, len );
  
          return encoded;
      }
  
      @SuppressWarnings( "checkstyle:magicnumber" )
      public byte[] encode()
      {
         if ( getDataType() != Void.class )
         {
             throw new IllegalArgumentException( "Data type can be only " + getDataType() );
         }
         byte[] encoded = new byte[8];
         int command = getId();
         setCommandAndDataLength( command, 0, encoded );
         return encoded;
     }
 
     public static Command decode( DataInputStream is )
         throws IOException
     {
         MasterProcessCommand command = resolve( is.readInt() );
         if ( command == null )
         {
             return null;
         }
         else
         {
             int dataLength = is.readInt();
             if ( dataLength > 0 )
             {
                 byte[] buffer = new byte[ dataLength ];
                 is.readFully( buffer );
 
                 if ( command.getDataType() == Void.class )
                 {
                     throw new IOException( format( "Command %s unexpectedly read Void data with length %d.",
                                                    command, dataLength ) );
                 }
 
                 String data = command.toDataTypeAsString( buffer );
                 return new Command( command, data );
             }
             else
             {
                 return new Command( command );
             }
         }
     }
 
     String toDataTypeAsString( byte... data )
     {
         switch ( this )
         {
             case RUN_CLASS:
             case SHUTDOWN:
                 return new String( data, US_ASCII );
             default:
                 return null;
         }
     }
 
     byte[] fromDataType( String data )
     {
         switch ( this )
         {
             case RUN_CLASS:
             case SHUTDOWN:
                 return data.getBytes( US_ASCII );
             default:
                 return new byte[0];
         }
     }
 
     static MasterProcessCommand resolve( int id )
     {
         for ( MasterProcessCommand command : values() )
         {
             if ( id == command.id )
             {
                 return command;
             }
         }
         return null;
     }
 
     @SuppressWarnings( "checkstyle:magicnumber" )
     static void setCommandAndDataLength( int command, int dataLength, byte... encoded )
     {
         encoded[0] = (byte) ( command >>> 24 );
         encoded[1] = (byte) ( command >>> 16 );
         encoded[2] = (byte) ( command >>> 8 );
         encoded[3] = (byte) command;
         encoded[4] = (byte) ( dataLength >>> 24 );
         encoded[5] = (byte) ( dataLength >>> 16 );
         encoded[6] = (byte) ( dataLength >>> 8 );
         encoded[7] = (byte) dataLength;
     }
 }