Added macros for __kindof support, thanks to https://github.com/omnigroup/OmniGroup/blob/master/Frameworks/OmniBase/macros.h#L37-L41

Redid generics macro, inspired similar to https://github.com/omnigroup/OmniGroup/blob/master/Frameworks/OmniBase/macros.h#L44-L50

Author: asciimike

FirebaseUI/API/FirebaseArray.h

@@ -53,7 +53,7 @@
 /**
  * The delegate object that array changes are surfaced to.
  */
-@property (strong, nonatomic) __GENERIC(NSMutableArray, FDataSnapshot *) *snapshots;
+@property (strong, nonatomic) NSMutableArray __GENERIC(FDataSnapshot *) *snapshots;
 
 #pragma mark -
 #pragma mark Initializer methods

FirebaseUI/API/FirebaseCollectionViewDataSource.h

@@ -66,7 +66,7 @@
 /**
  * The callback to populate a subclass of UICollectionViewCell with an object provided by the datasource.
  */
-@property (strong, nonatomic, __NON_NULL) void(^populateCell)(__kindof UICollectionViewCell * __NON_NULL_PTR cell, __kindof NSObject * __NON_NULL_PTR object);
+@property (strong, nonatomic, __NON_NULL) void(^populateCell)(__KINDOF UICollectionViewCell * __NON_NULL_PTR cell, __KINDOF NSObject * __NON_NULL_PTR object);
 
 /**
  * Initialize an instance of FirebaseCollectionViewDataSource that populates UICollectionViewCells with FDataSnapshots.
@@ -152,6 +152,6 @@
  * This method populates the fields of a UICollectionViewCell or subclass given an FDataSnapshot (or custom model object).
  * @param callback A block which returns an initialized UICollectionViewCell (or subclass) and the corresponding object to populate the cell with.
  */
-- (void)populateCellWithBlock:(__NON_NULL void(^)(__kindof UICollectionViewCell * __NON_NULL_PTR cell, __kindof NSObject * __NON_NULL_PTR object))callback;
+- (void)populateCellWithBlock:(__NON_NULL void(^)(__KINDOF UICollectionViewCell * __NON_NULL_PTR cell, __KINDOF NSObject * __NON_NULL_PTR object))callback;
 
 @end

FirebaseUI/API/FirebaseTableViewDataSource.h

@@ -61,7 +61,7 @@
 /**
  * The callback to populate a subclass of UITableViewCell with an object provided by the datasource.
  */
-@property (strong, nonatomic, __NON_NULL) void(^populateCell)(__kindof UITableViewCell * __NON_NULL_PTR cell, __kindof NSObject * __NON_NULL_PTR object);
+@property (strong, nonatomic, __NON_NULL) void(^populateCell)(__KINDOF UITableViewCell * __NON_NULL_PTR cell, __KINDOF NSObject * __NON_NULL_PTR object);
 
 /**
  * Initialize an instance of FirebaseTableViewDataSource that populates UITableViewCells with FDataSnapshots.
@@ -147,7 +147,7 @@
  * This method populates the fields of a UITableViewCell or subclass given a model object (or FDataSnapshot).
  * @param callback A block which returns an initialized UITableViewCell (or subclass) and the corresponding object to populate the cell with.
  */
-- (void)populateCellWithBlock:(nonnull void (^)(__kindof UITableViewCell * __NON_NULL_PTR cell, __kindof NSObject * __NON_NULL_PTR object))callback;
+- (void)populateCellWithBlock:(nonnull void (^)(__KINDOF UITableViewCell * __NON_NULL_PTR cell, __KINDOF NSObject * __NON_NULL_PTR object))callback;
 
 @end
 

FirebaseUI/Implementation/FirebaseCollectionViewDataSource.m

@@ -169,7 +169,7 @@ -(NSInteger)collectionView:(nonnull UICollectionView *)collectionView numberOfIt
     return [self.array count];
 }
 
-- (void)populateCellWithBlock:(__NON_NULL void(^)(__kindof UICollectionViewCell * __NON_NULL_PTR cell, __kindof NSObject * __NON_NULL_PTR object))callback;
+- (void)populateCellWithBlock:(__NON_NULL void(^)(__KINDOF UICollectionViewCell * __NON_NULL_PTR cell, __KINDOF NSObject * __NON_NULL_PTR object))callback;
 {
     self.populateCell = callback;
 }

FirebaseUI/Implementation/FirebaseTableViewDataSource.m

@@ -172,7 +172,7 @@ - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger
     return [self.array count];
 }
 
-- (void)populateCellWithBlock:(nonnull void (^)(__kindof UITableViewCell * __NON_NULL_PTR cell, __kindof NSObject * __NON_NULL_PTR object))callback;
+- (void)populateCellWithBlock:(nonnull void (^)(__KINDOF UITableViewCell * __NON_NULL_PTR cell, __KINDOF NSObject * __NON_NULL_PTR object))callback;
 {
     self.populateCell = callback;
 }

FirebaseUI/XCodeMacros.h

@@ -29,7 +29,7 @@
 #ifndef XCodeMacros_h
 #define XCodeMacros_h
 
-#if __has_feature(nullability)
+#if defined(__has_feature) && __has_feature(nullability)
 #   define __ASSUME_NONNULL_BEGIN      NS_ASSUME_NONNULL_BEGIN
 #   define __ASSUME_NONNULL_END        NS_ASSUME_NONNULL_END
 #   define __NULLABLE                  nullable
@@ -45,12 +45,16 @@
 #   define __NON_NULL_PTR
 #endif
 
-#if __has_feature(objc_generics)
-#   define __GENERIC(class, ...)      class<__VA_ARGS__>
-#   define __GENERIC_TYPE(type)       type
+#if defined(__has_feature) && __has_feature(objc_generics)
+#   define __GENERIC(...)       <__VA_ARGS__>
 #else
-#   define __GENERIC(class, ...)      class
-#   define __GENERIC_TYPE(type)       id
+#   define __GENERIC(...)
 #endif
 
-#endif /* XCodeMacros_h */
+#if defined(__has_feature) && __has_feature(objc_kindof)
+#   define __KINDOF             __kindof
+#else
+#   define __KINDOF
+#endif
+
+#endif