diff -r 000000000000 -r 3d3dcc3116d5 ConcurrentOperation.m
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ConcurrentOperation.m	Wed Apr 02 14:45:33 2008 -0700
@@ -0,0 +1,67 @@
+//
+//  ConcurrentOperation.m
+//  MYUtilities
+//
+//  Created by Jens Alfke on 2/5/08.
+//  Copyright 2008 Jens Alfke. All rights reserved.
+//
+
+#import "ConcurrentOperation.h"
+
+// See file:///Developer/Documentation/DocSets/com.apple.ADC_Reference_Library.CoreReference.docset/Contents/Resources/Documents/documentation/Cocoa/Reference/NSOperation_class/Reference/Reference.html#//apple_ref/doc/uid/TP40004591-RH2-DontLinkElementID_4
+
+
+@implementation ConcurrentOperation
+
+
+- (BOOL) isConcurrent {return YES;}
+
+- (void) main
+{
+    Assert(NO,@"Shouldn't call -main method of ConcurrentOperation");
+}
+
+- (BOOL) isExecuting
+{
+    return _isExecuting;
+}
+
+- (BOOL) isFinished
+{
+    return _isFinished;
+}
+
+- (void) start
+{
+    // don't call super!
+    Log(@"Starting %@",self);
+    [self willChangeValueForKey: @"isExecuting"];
+    _isExecuting = YES;
+    [self didChangeValueForKey: @"isExecuting"];
+}
+
+- (void) finish
+{
+    Log(@"Finished %@",self);
+    [self willChangeValueForKey: @"isExecuting"];
+    [self willChangeValueForKey: @"isFinished"];
+    _isExecuting = NO;
+    _isFinished = YES;
+    [self didChangeValueForKey: @"isFinished"];
+    [self didChangeValueForKey: @"isExecuting"];
+}
+
+
+- (void) cancel
+{
+    Log(@"Canceling %@",self);
+    [super cancel];
+    if( _isExecuting ) {
+        [self willChangeValueForKey: @"isExecuting"];
+        _isExecuting = NO;
+        [self didChangeValueForKey: @"isExecuting"];
+    }
+}
+
+
+@end