Custom NSKeyValueObservingOptions to add FBKVONotificationKeyPathKey

FBKVOController/FBKVOController.h

@@ -39,6 +39,13 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+/**
+ Additional option that may be passed to @c NSKeyValueObservingOptions mask.
+ When provided, and observing a keyPath, the @c FBKVONotificationKeyPathKey key will be added to the @c change dictionary.
+ This option is added automatically for any method passing multiple keyPaths.
+ */
+static NSKeyValueObservingOptions const FBKeyValueObservingOptionKeyPath = (1 << NSKeyValueObservingOptionPrior);
+
 /**
  Key provided in the @c change dictionary of @c FBKVONotificationBlock that's value represents the key-path being observed
  */

FBKVOController/FBKVOController.m

@@ -35,6 +35,9 @@
     case NSKeyValueObservingOptionPrior:
       return @"NSKeyValueObservingOptionPrior";
       break;
+    case FBKeyValueObservingOptionKeyPath:
+      return @"FBKeyValueObservingOptionKeyPath";
+      break;
     default:
       NSCAssert(NO, @"unexpected option %tu", option);
       break;
@@ -372,23 +375,23 @@ - (void)observeValueForKeyPath:(nullable NSString *)keyPath
       id observer = controller.observer;
       if (nil != observer) {
 
+        NSDictionary<NSKeyValueChangeKey, id> *changeWithKeyPath = change;
+        // add the keyPath to the change dictionary for clarity when mulitple keyPaths are being observed
+        if (keyPath && (info->_options & FBKeyValueObservingOptionKeyPath) != 0) {
+          NSMutableDictionary<NSKeyValueChangeKey, id> *mChange = [NSMutableDictionary dictionaryWithObject:keyPath forKey:FBKVONotificationKeyPathKey];
+          [mChange addEntriesFromDictionary:change];
+          changeWithKeyPath = [mChange copy];
+        }
         // dispatch custom block or action, fall back to default action
         if (info->_block) {
-          NSDictionary<NSKeyValueChangeKey, id> *changeWithKeyPath = change;
-          // add the keyPath to the change dictionary for clarity when mulitple keyPaths are being observed
-          if (keyPath) {
-            NSMutableDictionary<NSString *, id> *mChange = [NSMutableDictionary dictionaryWithObject:keyPath forKey:FBKVONotificationKeyPathKey];
-            [mChange addEntriesFromDictionary:change];
-            changeWithKeyPath = [mChange copy];
-          }
           info->_block(observer, object, changeWithKeyPath);
         } else if (info->_action) {
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Warc-performSelector-leaks"
-          [observer performSelector:info->_action withObject:change withObject:object];
+          [observer performSelector:info->_action withObject:changeWithKeyPath withObject:object];
 #pragma clang diagnostic pop
         } else {
-          [observer observeValueForKeyPath:keyPath ofObject:object change:change context:info->_context];
+          [observer observeValueForKeyPath:keyPath ofObject:object change:changeWithKeyPath context:info->_context];
         }
       }
     }
@@ -590,7 +593,7 @@ - (void)observe:(nullable id)object keyPaths:(NSArray<NSString *> *)keyPaths opt
   }
 
   for (NSString *keyPath in keyPaths) {
-    [self observe:object keyPath:keyPath options:options block:block];
+    [self observe:object keyPath:keyPath options:options|FBKeyValueObservingOptionKeyPath block:block];
   }
 }
 
@@ -618,7 +621,7 @@ - (void)observe:(nullable id)object keyPaths:(NSArray<NSString *> *)keyPaths opt
   }
 
   for (NSString *keyPath in keyPaths) {
-    [self observe:object keyPath:keyPath options:options action:action];
+    [self observe:object keyPath:keyPath options:options|FBKeyValueObservingOptionKeyPath action:action];
   }
 }
 
@@ -644,7 +647,7 @@ - (void)observe:(nullable id)object keyPaths:(NSArray<NSString *> *)keyPaths opt
   }
 
   for (NSString *keyPath in keyPaths) {
-    [self observe:object keyPath:keyPath options:options context:context];
+    [self observe:object keyPath:keyPath options:options|FBKeyValueObservingOptionKeyPath context:context];
   }
 }
 

FBKVOControllerTests/FBKVOControllerTests.m

@@ -30,6 +30,7 @@ @implementation FBKVOControllerTests
 static void *context = (void *)@"context";
 static NSKeyValueObservingOptions const optionsNone = 0;
 static NSKeyValueObservingOptions const optionsBasic = NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld | NSKeyValueObservingOptionInitial;
+static NSKeyValueObservingOptions const optionsBasicWithCustomOption =  optionsBasic | FBKeyValueObservingOptionKeyPath;
 static NSKeyValueObservingOptions const optionsAll = optionsBasic | NSKeyValueObservingOptionPrior;
 
 - (void)testDebugDescriptionContainsClassName
@@ -67,13 +68,56 @@ - (void)testBlockOptionsBasic
     blockKeyPath = change[FBKVONotificationKeyPathKey];
     blockCallCount++;
   }];
+  XCTAssert(1 == blockCallCount, @"unexpected block call count:%lu expected:%d", (unsigned long)blockCallCount, 1);
+  XCTAssert(blockObserver == observer, @"value:%@ expected:%@", blockObserver, observer);
+  XCTAssert(blockObject == referenceObserver.lastObject, @"value:%@ expected:%@", blockObject, referenceObserver.lastObject);
+  XCTAssertNil(blockKeyPath, @"value:%@ expected:nil", blockKeyPath);
+  XCTAssertEqualObjects(blockChange, referenceObserver.lastChange, @"value:%@ expected:%@", blockChange, referenceObserver.lastChange);
+
+  circle.radius = 1.0;
+  XCTAssert(2 == blockCallCount, @"unexpected block call count:%lu expected:%d", (unsigned long)blockCallCount, 2);
+  XCTAssert(blockObserver == observer, @"value:%@ expected:%@", blockObserver, observer);
+  XCTAssert(blockObject == referenceObserver.lastObject, @"value:%@ expected:%@", blockObject, referenceObserver.lastObject);
+  XCTAssertNil(blockKeyPath, @"value:%@ expected:nil", blockKeyPath);
+  XCTAssertEqualObjects(blockChange, referenceObserver.lastChange, @"value:%@ expected:%@", blockChange, referenceObserver.lastChange);
 
+  // cleanup
+  [circle removeObserver:referenceObserver forKeyPath:radius];
+}
+
+- (void)testBlockOptionsBasicWithCustomOption
+{
+  FBKVOTestCircle *circle = [FBKVOTestCircle circle];
+  id<FBKVOTestObserving> observer = mockProtocol(@protocol(FBKVOTestObserving));
+  FBKVOController *controller = [FBKVOController controllerWithObserver:observer];
+  FBKVOTestObserver *referenceObserver = [FBKVOTestObserver observer];
+
+  // add reference observe
+  [circle addObserver:referenceObserver forKeyPath:radius options:optionsBasicWithCustomOption context:context];
+
+  __block NSUInteger blockCallCount = 0;
+  __block id blockObserver = nil;
+  __block id blockObject = nil;
+  __block NSString *blockKeyPath = nil;
+  __block NSDictionary *blockChange = nil;
+
+  // add mock observer
+  [controller observe:circle keyPath:radius options:optionsBasicWithCustomOption block:^(id observer, id object, NSDictionary *change) {
+    blockObserver = observer;
+    blockObject = object;
+    NSMutableDictionary *mChange = [change mutableCopy];
+    [mChange removeObjectForKey:FBKVONotificationKeyPathKey];
+    blockChange = [mChange copy];
+    blockKeyPath = change[FBKVONotificationKeyPathKey];
+    blockCallCount++;
+  }];
+
   XCTAssert(1 == blockCallCount, @"unexpected block call count:%lu expected:%d", (unsigned long)blockCallCount, 1);
   XCTAssert(blockObserver == observer, @"value:%@ expected:%@", blockObserver, observer);
   XCTAssert(blockObject == referenceObserver.lastObject, @"value:%@ expected:%@", blockObject, referenceObserver.lastObject);
   XCTAssert([blockKeyPath isEqualToString:radius], @"value:%@ expected:%@", blockKeyPath, radius);
   XCTAssertEqualObjects(blockChange, referenceObserver.lastChange, @"value:%@ expected:%@", blockChange, referenceObserver.lastChange);
-  
+
   circle.radius = 1.0;
   XCTAssert(2 == blockCallCount, @"unexpected block call count:%lu expected:%d", (unsigned long)blockCallCount, 2);
   XCTAssert(blockObserver == observer, @"value:%@ expected:%@", blockObserver, observer);
@@ -195,9 +239,11 @@ - (void)testObserveKeyPathsOptionsBlockObservesEachOfTheKeyPaths
 
   // Arrange 2: Observe the key paths "radius" and "borderWidth" on the circle.
   //            Aggregate the new values in an array.
+  NSMutableArray *observedKeys = [NSMutableArray array];
   NSMutableArray *newValues = [NSMutableArray array];
   FBKVOTestCircle *circle = [FBKVOTestCircle circle];
   [controller observe:circle keyPaths:@[radius, borderWidth] options:NSKeyValueObservingOptionNew block:^(id observer, FBKVOTestCircle *circle, NSDictionary *change) {
+    [observedKeys addObject:change[FBKVONotificationKeyPathKey]];
     [newValues addObject:change[NSKeyValueChangeNewKey]];
   }];
 
@@ -206,6 +252,7 @@ - (void)testObserveKeyPathsOptionsBlockObservesEachOfTheKeyPaths
   circle.borderWidth = 10.f;
 
   // Assert: Changes to the radius and borderWidth should have been observed.
+  assertThat(observedKeys, equalTo(@[radius, borderWidth]));
   assertThat(newValues, equalTo(@[@1, @10]));
 }