/*********************************************

	Copyright © 2001 Jason Lamport.
	All rights reserved.

----------------------
*******************************************/

package com.strangelight.mactoolbox;

import com.apple.jdirect.*;
import com.apple.mrj.jdirect.*;


/**
 *	Extends J_HandleStruct by providing an additional constructor
 *	for allocating a new Handle, and automatically disposing of its
 *	handle on finalize() (regardless of whether the handle was originally
 *	created by the J_DisposableHandle object or not)
 *	
 *	Be careful *not* to let this object get garbage-collected as long as
 *	someone, somewhere may need to access the handle that it encapsulates.
 */
public class J_DisposableHandle extends J_HandleStruct {

	public static class NewHandle {
		private int size;
		public NewHandle(int s) {
			size = s;
		}
		public int get_size() {
			return size;
		}
	}

	public J_DisposableHandle(int new_handle) {
		super( new_handle );
	}

	public J_DisposableHandle( NewHandle newH ) throws E_OSErr {
		super( allocate_handle( newH.get_size() ) );
		handle_size = newH.get_size();
	}

	public void finalize() {
		if ( handle != 0 ) {
			MemoryFunctions.DisposeHandle( handle );
		}
	}
	
	protected static int allocate_handle( int size ) throws E_OSErr {
		int osErr = 0;
		int new_hand = 0;
				
		new_hand = MemoryFunctions.NewHandle( size );
		if ( new_hand == 0 ) { 
			osErr = MemoryFunctions.MemError();
			if ( osErr == ErrorConstants.memFullErr ) {
				/*
					Run the garbage collector, then try again:
				 */
				System.gc();
				new_hand = MemoryFunctions.NewHandle( size );
				if ( new_hand == 0 ) { 
					throw new E_OSErr( 
						"Can't allocate new Handle for J_HandleStruct (gc() failed?)",
						MemoryFunctions.MemError()
					);
				}
			} else {
				//	unknown error:
				throw new E_OSErr( 
					"Can't allocate new Handle for J_HandleStruct because of an unknown error.",
					osErr
				);
			}
		}
		return new_hand;
	}
}