• Added method -[SSYOperationQueue tearDown].

• Added comment un-recommending SSYMOCManager.

Author: jerrykrinock

SSYMOCManager.h

@@ -14,6 +14,10 @@
  which the owner is desired turns out to not be one of this class's creations.
  This class itself is instantiated as an app-wide
  singleton and no public instance methods are available.
+
+ UPDATE 2018-12-28.  I do not recommend using this class, which I wrote I
+ think in 2009, any more, because it is easy to cause retain cycles which are
+ tricky to unravel.
  
  When using this class, [NSApp delegate] must conform to protocol 
  SSYAppSupporter.

SSYManagedObject.h

@@ -121,6 +121,8 @@ extern NSString* const constKeyNewValue ;
  and definition of "owner".  If the owner must be of a specific type or
  conform to a certain formal protocol, you can re-declare and override this
  method in subclasses.  The implementation simply returns super's owner.
+
+ UPDATE 2018-12-28.  This method is not recommended.  Use -allocOwner instead.
  @result   The owner of the receiver
 */
 - (id)owner;
@@ -130,11 +132,15 @@ extern NSString* const constKeyNewValue ;
  that is not in the autorelease pool – the caller "owns" it
 
  @details  This method is recommended instead of -owner whenever the owner is
- a transient object which may not be deallocced due to retain cycles with the
- receiver.  Keep in mind that Core Data can be quite  anal-retentive:
+ a transient object which may not be deallocced for a long time due to the
+ unpredictable release of the autoreleased owner.  This may be exacerbated by
+ the anal-retentive nature of Core Data, some of which is explained in here.
 
  https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/CoreData/MO_Lifecycle.html
 
+ Note that the problem being solved here is an artifact of autorelease pools.
+ The problem would be moot if we were using Automatic Reference Counting (ARC).
+
  The reason for the prefix 'alloc' is that, of the four prefixes which
  tell the clang objective-c static analyzer that this method returns an object
  which the caller "owns", as explained here

SSYOperationQueue.h

@@ -284,4 +284,14 @@ extern NSString* const SSYOperationQueueDidEndWorkNotification ;
 
 - (void)doDone:(NSDictionary*)doneInfo ;
 
+/*!
+ @brief    Removes an internal observer which observes the owner of the first
+ operation in the receiver's queue.
+
+ @details  To prevent crashes, you should send this prior to the owner of the
+ receiver's operations being deallocced.
+ */
+
+- (void)tearDown;
+
 @end

SSYOperationQueue.m

@@ -20,6 +20,7 @@
 @interface SSYOperationQueue ()
 
 @property (retain) id noAppNapActivity ;
+@property (assign) BOOL didTearDown;
 
 @end
 
@@ -128,11 +129,18 @@ - (id)init {
 	return self ;
 }
 
+- (void)tearDown {
+    if (!self.didTearDown) {
+        [self removeObserver:self
+                  forKeyPath:@"operations"];
+        self.didTearDown = YES;
+    }
+}
+
 - (void)dealloc {
-	// Probably this is not necessary but I'm paranoid about KVO.
-	[self removeObserver:self
-			  forKeyPath:@"operations"] ;
-	
+    /* This should have already been done, but in case not… */
+    [self tearDown];
+
 	[m_error release] ;
 	[m_scriptCommand release] ;
 	[m_scriptResult release] ;