A Namespace Extension Toolkit

/*
 Copyright 2005 Chad Yoshikawa
 http://www.ececs.uc.edu/~yoshikco
 yoshikco@ececs.uc.edu

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 This program 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 for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

*/
using System;
using System.Net.Sockets;
using System.Diagnostics;
using System.IO;

namespace CSharpFileSystem.Commands
{
	/// <summary>
	/// A factory that will create commands based the opcode read over the wire (otw)
	/// </summary>
	public class FileSystemCommandFactory
	{

		enum FILESYSTEM_OPCODES {
			LISTFILES_OPCODE=1,
			READ_OPCODE=2,
			WRITE_OPCODE=3,
			STAT_OPCODE=4,
			CREATEDIR_OPCODE=5,
			DELETE_OPCODE=6,
			CREATEFILE_OPCODE=7,
			COMMAND_OPCODE=8,
			COPY_OPCODE=9
		} ;
		
		/// <summary>
		/// Cannot create this object -- just use the static methods
		/// @see CreateCommand()
		/// </summary>
		private FileSystemCommandFactory()
		{
		}

		/// <summary>
		/// The factory method for creating commands based on the next opcode otw
		/// </summary>
		/// <param name="reader">The stream representing the wire from the NSE</param>
		/// <param name="writer">The stream representing the wire to the NSE</param>
		/// <returns>The newly minted command</returns>
		public static FileSystemCommand CreateCommand(BinaryReader reader, BinaryWriter writer) {
			FileSystemCommand ret = null;
			int opcode = IOLibrary.ReadInt(reader); // 4 byte fixed length opcode
			switch (opcode) {
				case (int)FILESYSTEM_OPCODES.LISTFILES_OPCODE:
					// for now, just supply the 'list files command'
					ret = new Commands.ListFilesCommand(reader,writer);
					break;
				case (int)FILESYSTEM_OPCODES.READ_OPCODE:
					ret = new Commands.ReadCommand(reader,writer);
					break;
				case (int)FILESYSTEM_OPCODES.WRITE_OPCODE:
					ret = new Commands.WriteCommand(reader,writer);
					break;
				case (int)FILESYSTEM_OPCODES.STAT_OPCODE:
					ret = new Commands.StatCommand(reader,writer);
					break;
				case (int)FILESYSTEM_OPCODES.CREATEDIR_OPCODE:
					ret = new Commands.CreateDirectoryCommand(reader,writer);
					break;
				case (int)FILESYSTEM_OPCODES.DELETE_OPCODE:
					ret = new Commands.DeleteCommand(reader,writer);
					break;
				case (int)FILESYSTEM_OPCODES.CREATEFILE_OPCODE:
					ret = new Commands.CreateFileCommand(reader,writer);
					break;
				case (int)FILESYSTEM_OPCODES.COMMAND_OPCODE:
					ret = new Commands.CommandCommand(reader,writer);
					break;
				case (int)FILESYSTEM_OPCODES.COPY_OPCODE:
					ret = new Commands.CopyCommand(reader,writer);
					break;
				default:
					// error
					Debug.WriteLine("Error -- invalid opcode requested "+opcode);
					break;
			} // end switch
			
			return (ret);
		} // end CreateCommand
	} // end class
} // end namespace