/* ProcessImpl.java --
   Copyright (C) 2003 David Belanger <dbelan2@cs.mcgill.ca>
 
This file is part of GNU Classpath.
 
GNU Classpath 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, or (at your option)
any later version.
 
GNU Classpath 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 GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.
 
Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.
 
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */

package java.lang;

import java.io.*;

/**
 *
 * An implementation of <code>Process</code>.
 *
 * @author David Belanger <dbelan2@cs.mcgill.ca>
 *
 */
public class ProcessImpl extends Process
{

  private int pid;
  private FileDescriptor outFd;
  private FileDescriptor inFd;
  private FileDescriptor errFd;

  private OutputStream out;
  private InputStream in;
  private InputStream err;

  private boolean hasExited = false;
  private int exitValue;


  public ProcessImpl(int pid,
                     FileDescriptor inFd,
                     FileDescriptor outFd,
                     FileDescriptor errFd)
  {
    this.pid = pid;
    this.outFd = outFd;
    this.inFd = inFd;
    this.errFd = errFd;

    /*
    System.err.println("In ProcessImp constructor, FDs are: ");
    System.err.println(inFd.getNativeFD());
    System.err.println(outFd.getNativeFD());
    System.err.println(errFd.getNativeFD());
    System.err.println("------");
    */
  }


  public OutputStream getOutputStream()
  {
    if (out == null)
    {
      out = new FileOutputStream(outFd);
    }
    return out;
  }

  public InputStream getInputStream()
  {
    if (in == null)
    {
      in = new FileInputStream(inFd);
    }
    return in;
  }

  public InputStream getErrorStream()
  {
    if (err == null)
    {
      err = new FileInputStream(errFd);
    }
    return err;
  }

  public int waitFor() throws InterruptedException
  {
    return wait(false);
  }

  public int exitValue()
  {
    try {
      return wait(true);
    } catch (InterruptedException e) {
      // should never occur...
      System.err.println(e);
      System.exit(1);
      return 0;
    }
  }



  /*
   *
   * If nonBlocking is true, this method will not block and will
   * throw an IllegalThreadStateException if the child process has
   * not exited.
   *
   * It will throw an InterruptedException, if the thread is interrupted
   * while waiting.
   *
   * TODO: Implement thread interruption in SableVM.
   *
   */
  private int wait(boolean nonBlocking) throws InterruptedException
  {
    if (!hasExited)
    {
      exitValue = nativeWaitFor(pid, nonBlocking);
      if (exitValue == -1) {
	throw new IllegalThreadStateException();
      } else if (exitValue == -2) {
	// What to do???
	System.err.println("Child did not exit normally.");
	System.exit(1);
      } else if (exitValue == -3) {
        throw new InterruptedException();
      }
      hasExited = true;
    }
    return exitValue;
  }

  // -1 indicates that needs to throw IllegalThreadStateException.
  // -2 indicates another error condition.  Ex: child did not exited
  //    normally, so we don't have an exit value...
  // -3 indicates that needs to throw InterruptedException.
  private native int nativeWaitFor(int pid, boolean nonBlocking)
    throws InterruptedException;


  public void destroy()
  {
    nativeDestroy(pid);
  }

  public native void nativeDestroy(int pid);



}