Merge pull request #27 from telly/nsobject-category

Add NSObject category with a convenient, lazy loaded KVOController

FBKVOController/FBKVOController.h

@@ -135,3 +135,15 @@ typedef void (^FBKVONotificationBlock)(id observer, id object, NSDictionary *cha
 - (void)unobserveAll;
 
 @end
+
+@interface NSObject (FBKVOController)
+
+/**
+ @abstract Lazy-loaded FBKVOController for use with any object
+ @return FBKVOController associated with this object, creating one if necessary
+ @discussion This makes it convenient to simply create and forget a FBKVOController, and when this object gets dealloc'd, so will the associated controller and the observation info.
+ */
+@property (nonatomic, strong) FBKVOController *KVOController;
+@property (nonatomic, strong) FBKVOController *KVOControllerNonRetaining;
+
+@end

FBKVOController/FBKVOController.m

@@ -622,3 +622,48 @@ - (void)unobserveAll
 }
 
 @end
+
+#pragma mark NSObject Category -
+
+static void *NSObjectKVOControllerKey = &NSObjectKVOControllerKey;
+static void *NSObjectKVOControllerNonRetainingKey = &NSObjectKVOControllerNonRetainingKey;
+
+@implementation NSObject (FBKVOController)
+
+- (FBKVOController *)KVOController
+{
+  id controller = objc_getAssociatedObject(self, NSObjectKVOControllerKey);
+
+  // lazily create the KVOController
+  if (nil == controller) {
+    controller = [FBKVOController controllerWithObserver:self];
+    self.KVOController = controller;
+  }
+
+  return controller;
+}
+
+- (void)setKVOController:(FBKVOController *)KVOController
+{
+  objc_setAssociatedObject(self, NSObjectKVOControllerKey, KVOController, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+}
+
+- (FBKVOController *)KVOControllerNonRetaining
+{
+  id controller = objc_getAssociatedObject(self, NSObjectKVOControllerNonRetainingKey);
+
+  if (nil == controller) {
+    controller = [[FBKVOController alloc] initWithObserver:self retainObserved:NO];
+    self.KVOControllerNonRetaining = controller;
+  }
+
+  return controller;
+}
+
+- (void)setKVOControllerNonRetaining:(FBKVOController *)KVOControllerNonRetaining
+{
+  objc_setAssociatedObject(self, NSObjectKVOControllerNonRetainingKey, KVOControllerNonRetaining, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+}
+
+@end
+