content: /*******************************************************************************
  * Copyright (c) 2009 Luaj.org. All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  ******************************************************************************/
  package org.luaj.vm2.lib.jse;
  
  import java.io.File;
  import java.io.IOException;
  
  import org.luaj.vm2.LuaValue;
  import org.luaj.vm2.Varargs;
  import org.luaj.vm2.lib.LibFunction;
  
  /**
   * Subclass of {@link LibFunction} which implements the standard lua {@code os} library.
   * <p>
   * This contains more complete implementations of the following functions 
   * using features that are specific to JSE:   
   * <ul>
   * <li>{@code execute()}</li>
   * <li>{@code remove()}</li>
   * <li>{@code rename()}</li>
   * <li>{@code tmpname()}</li>
   * </ul>
   * <p>
   * Because the nature of the {@code os} library is to encapsulate 
   * os-specific features, the behavior of these functions varies considerably 
   * from their counterparts in the C platform.  
   * <p>
   * Typically, this library is included as part of a call to 
   * {@link JsePlatform#standardGlobals()}
   * <pre> {@code
   * Globals globals = JsePlatform.standardGlobals();
   * System.out.println( globals.get("os").get("time").call() );
   * } </pre>
   * <p>
   * For special cases where the smallest possible footprint is desired, 
   * a minimal set of libraries could be loaded
   * directly via {@link Globals#load(LuaValue)} using code such as:
   * <pre> {@code
   * Globals globals = new Globals();
   * globals.load(new JseBaseLib());
   * globals.load(new PackageLib());
   * globals.load(new JseOsLib());
   * System.out.println( globals.get("os").get("time").call() );
   * } </pre>
   * <p>However, other libraries such as <em>MathLib</em> are not loaded in this case.
   * <p>
   * @see LibFunction
   * @see OsLib
   * @see JsePlatform
   * @see org.luaj.vm2.lib.jme.JmePlatform
   * @see <a href="http://www.lua.org/manual/5.2/manual.html#6.9">Lua 5.2 OS Lib Reference</a>
   */
  public class JseOsLib extends org.luaj.vm2.lib.OsLib {
  
  	/** return code indicating the execute() threw an I/O exception */
  	public static int EXEC_IOEXCEPTION =  1;
  
  	/** return code indicating the execute() was interrupted */
  	public static int EXEC_INTERRUPTED = -2;
  
  	/** return code indicating the execute() threw an unknown exception */
  	public static int EXEC_ERROR       = -3;
  
  	/** public constructor */
  	public JseOsLib() {
  	}
  
  	protected Varargs execute(String command) {
  		int exitValue;
  		try {
  //			exitValue = new JseProcess(command, null, globals.STDOUT, globals.STDERR).waitFor();
  			exitValue = new JseProcess(command, null, null, null).waitFor();
  		} catch (IOException ioe) {
  			exitValue = EXEC_IOEXCEPTION;
  		} catch (InterruptedException e) {
  			exitValue = EXEC_INTERRUPTED;
  		} catch (Throwable t) {
  			exitValue = EXEC_ERROR;
  		}
  		if (exitValue == 0)
  			return varargsOf(TRUE, valueOf("exit"), ZERO);
  		return varargsOf(NIL, valueOf("signal"), valueOf(exitValue));
  	}
  
  	protected void remove(String filename) throws IOException {
  		File f = new File(filename);
  		if ( ! f.exists() )
  			throw new IOException("No such file or directory");
  		if ( ! f.delete() )
  			throw new IOException("Failed to delete");
  	}
  
  	protected void rename(String oldname, String newname) throws IOException {
  		File f = new File(oldname);
  		if ( ! f.exists() )
  			throw new IOException("No such file or directory");
  		if ( ! f.renameTo(new File(newname)) )
  			throw new IOException("Failed to delete");
  	}
  
  	protected String tmpname() {
  		try {
  			java.io.File f = java.io.File.createTempFile(TMP_PREFIX ,TMP_SUFFIX);
  			return f.getName();
  		} catch ( IOException ioe ) {
  			return super.tmpname();
  		}
  	}
  
  }
  