Allow same library for app and extensions.

clang will silence availability errors in classes and methods that are also unavailable to the target.  The following have been made unavailable to app extensions:
- `AFNetworkActivityIndicatorManager` class
- `UIAlertView` category methods
- `AFURLConnectionOperation setShouldExecuteAsBackgroundTaskWithExpirationHandler:`

Benefits of change:
- Fixes CocoaPods support for App Extensions.
- Allows single framework to be used in app.
- Eliminates the need for `AF_APP_EXTENSIONS`.

AFNetworking/AFURLConnectionOperation.h

@@ -73,10 +73,6 @@
 
  Connections will be validated on all matching certificates with a `.cer` extension in the bundle root.
 
- ## App Extensions
-
- When using AFNetworking in an App Extension, `#define AF_APP_EXTENSIONS` to avoid using unavailable APIs.
-
  ## NSCoding & NSCopying Conformance
 
  `AFURLConnectionOperation` conforms to the `NSCoding` and `NSCopying` protocols, allowing operations to be archived to disk, and copied in memory, respectively. However, because of the intrinsic limitations of capturing the exact state of an operation at a particular moment, there are some important caveats to keep in mind:
@@ -270,8 +266,8 @@ NS_ASSUME_NONNULL_BEGIN
 
  @param handler A handler to be called shortly before the application’s remaining background time reaches 0. The handler is wrapped in a block that cancels the operation, and cleans up and marks the end of execution, unlike the `handler` parameter in `UIApplication -beginBackgroundTaskWithExpirationHandler:`, which expects this to be done in the handler itself. The handler is called synchronously on the main thread, thus blocking the application’s suspension momentarily while the application is notified.
   */
-#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && !defined(AF_APP_EXTENSIONS)
-- (void)setShouldExecuteAsBackgroundTaskWithExpirationHandler:(nullable void (^)(void))handler;
+#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)
+- (void)setShouldExecuteAsBackgroundTaskWithExpirationHandler:(nullable void (^)(void))handler NS_EXTENSION_UNAVAILABLE_IOS("Not available in app extensions.");
 #endif
 
 ///---------------------------------

AFNetworking/AFURLConnectionOperation.m

@@ -37,12 +37,6 @@ typedef NS_ENUM(NSInteger, AFOperationState) {
     AFOperationFinishedState    = 3,
 };
 
-#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && !defined(AF_APP_EXTENSIONS)
-typedef UIBackgroundTaskIdentifier AFBackgroundTaskIdentifier;
-#else
-typedef id AFBackgroundTaskIdentifier;
-#endif
-
 static dispatch_group_t url_request_operation_completion_group() {
     static dispatch_group_t af_url_request_operation_completion_group;
     static dispatch_once_t onceToken;
@@ -72,6 +66,7 @@ typedef void (^AFURLConnectionOperationProgressBlock)(NSUInteger bytes, long lon
 typedef void (^AFURLConnectionOperationAuthenticationChallengeBlock)(NSURLConnection *connection, NSURLAuthenticationChallenge *challenge);
 typedef NSCachedURLResponse * (^AFURLConnectionOperationCacheResponseBlock)(NSURLConnection *connection, NSCachedURLResponse *cachedResponse);
 typedef NSURLRequest * (^AFURLConnectionOperationRedirectResponseBlock)(NSURLConnection *connection, NSURLRequest *request, NSURLResponse *redirectResponse);
+typedef void (^AFURLConnectionOperationBackgroundTaskCleanupBlock)();
 
 static inline NSString * AFKeyPathFromOperationState(AFOperationState state) {
     switch (state) {
@@ -144,7 +139,7 @@ static inline BOOL AFStateTransitionIsValid(AFOperationState fromState, AFOperat
 @property (readwrite, nonatomic, copy) NSString *responseString;
 @property (readwrite, nonatomic, assign) NSStringEncoding responseStringEncoding;
 @property (readwrite, nonatomic, assign) long long totalBytesRead;
-@property (readwrite, nonatomic, assign) AFBackgroundTaskIdentifier backgroundTaskIdentifier;
+@property (readwrite, nonatomic, copy) AFURLConnectionOperationBackgroundTaskCleanupBlock backgroundTaskCleanup;
 @property (readwrite, nonatomic, copy) AFURLConnectionOperationProgressBlock uploadProgress;
 @property (readwrite, nonatomic, copy) AFURLConnectionOperationProgressBlock downloadProgress;
 @property (readwrite, nonatomic, copy) AFURLConnectionOperationAuthenticationChallengeBlock authenticationChallenge;
@@ -214,13 +209,10 @@ static inline BOOL AFStateTransitionIsValid(AFOperationState fromState, AFOperat
         [_outputStream close];
         _outputStream = nil;
     }
-
-#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && !defined(AF_APP_EXTENSIONS)
-    if (_backgroundTaskIdentifier) {
-        [[UIApplication sharedApplication] endBackgroundTask:_backgroundTaskIdentifier];
-        _backgroundTaskIdentifier = UIBackgroundTaskInvalid;
+    
+    if (_backgroundTaskCleanup) {
+        _backgroundTaskCleanup();
     }
-#endif
 }
 
 #pragma mark -
@@ -293,13 +285,22 @@ static inline BOOL AFStateTransitionIsValid(AFOperationState fromState, AFOperat
     [self.lock unlock];
 }
 
-#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && !defined(AF_APP_EXTENSIONS)
+#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)
 - (void)setShouldExecuteAsBackgroundTaskWithExpirationHandler:(void (^)(void))handler {
     [self.lock lock];
-    if (!self.backgroundTaskIdentifier) {
+    if (!self.backgroundTaskCleanup) {
         UIApplication *application = [UIApplication sharedApplication];
+        UIBackgroundTaskIdentifier __block backgroundTaskIdentifier = UIBackgroundTaskInvalid;
         __weak __typeof(self)weakSelf = self;
-        self.backgroundTaskIdentifier = [application beginBackgroundTaskWithExpirationHandler:^{
+        
+        self.backgroundTaskCleanup = ^(){
+            if (backgroundTaskIdentifier != UIBackgroundTaskInvalid) {
+                [[UIApplication sharedApplication] endBackgroundTask:backgroundTaskIdentifier];
+                backgroundTaskIdentifier = UIBackgroundTaskInvalid;
+            }
+        };
+        
+        backgroundTaskIdentifier = [application beginBackgroundTaskWithExpirationHandler:^{
             __strong __typeof(weakSelf)strongSelf = weakSelf;
 
             if (handler) {
@@ -308,9 +309,7 @@ static inline BOOL AFStateTransitionIsValid(AFOperationState fromState, AFOperat
 
             if (strongSelf) {
                 [strongSelf cancel];
-
-                [application endBackgroundTask:strongSelf.backgroundTaskIdentifier];
-                strongSelf.backgroundTaskIdentifier = UIBackgroundTaskInvalid;
+                strongSelf.backgroundTaskCleanup();
             }
         }];
     }

UIKit+AFNetworking/AFNetworkActivityIndicatorManager.h

@@ -41,6 +41,7 @@ NS_ASSUME_NONNULL_BEGIN
  See the Apple Human Interface Guidelines section about the Network Activity Indicator for more information:
  http://developer.apple.com/library/iOS/#documentation/UserExperience/Conceptual/MobileHIG/UIElementGuidelines/UIElementGuidelines.html#//apple_ref/doc/uid/TP40006556-CH13-SW44
  */
+NS_EXTENSION_UNAVAILABLE_IOS("Use view controller based solutions where appropriate instead.")
 @interface AFNetworkActivityIndicatorManager : NSObject
 
 /**

UIKit+AFNetworking/AFNetworkActivityIndicatorManager.m

@@ -113,9 +113,7 @@ static NSURLRequest * AFNetworkRequestFromNotification(NSNotification *notificat
 }
 
 - (void)updateNetworkActivityIndicatorVisibility {
-#if !defined(AF_APP_EXTENSIONS)
     [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:[self isNetworkActivityIndicatorVisible]];
-#endif
 }
 
 - (void)setActivityCount:(NSInteger)activityCount {

UIKit+AFNetworking/UIAlertView+AFNetworking.h

@@ -23,7 +23,7 @@
 
 #import <Availability.h>
 
-#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && !defined(AF_APP_EXTENSIONS)
+#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)
 
 #import <UIKit/UIKit.h>
 
@@ -48,7 +48,7 @@ NS_ASSUME_NONNULL_BEGIN
  */
 #if __IPHONE_OS_VERSION_MIN_REQUIRED >= 70000
 + (void)showAlertViewForTaskWithErrorOnCompletion:(NSURLSessionTask *)task
-                                         delegate:(nullable id)delegate;
+                                         delegate:(nullable id)delegate NS_EXTENSION_UNAVAILABLE_IOS("Not available in app extensions.");
 #endif
 
 /**
@@ -63,7 +63,7 @@ NS_ASSUME_NONNULL_BEGIN
 + (void)showAlertViewForTaskWithErrorOnCompletion:(NSURLSessionTask *)task
                                          delegate:(nullable id)delegate
                                 cancelButtonTitle:(nullable NSString *)cancelButtonTitle
-                                otherButtonTitles:(nullable NSString *)otherButtonTitles, ... NS_REQUIRES_NIL_TERMINATION;
+                                otherButtonTitles:(nullable NSString *)otherButtonTitles, ... NS_REQUIRES_NIL_TERMINATION NS_EXTENSION_UNAVAILABLE_IOS("Not available in app extensions.");
 #endif
 
 ///------------------------------------------
@@ -77,7 +77,7 @@ NS_ASSUME_NONNULL_BEGIN
  @param delegate The alert view delegate.
  */
 + (void)showAlertViewForRequestOperationWithErrorOnCompletion:(AFURLConnectionOperation *)operation
-                                                     delegate:(nullable id)delegate;
+                                                     delegate:(nullable id)delegate NS_EXTENSION_UNAVAILABLE_IOS("Not available in app extensions.");
 
 /**
  Shows an alert view with the error of the specified request operation, if any, with a custom cancel button title and other button titles.
@@ -90,7 +90,7 @@ NS_ASSUME_NONNULL_BEGIN
 + (void)showAlertViewForRequestOperationWithErrorOnCompletion:(AFURLConnectionOperation *)operation
                                                      delegate:(nullable id)delegate
                                             cancelButtonTitle:(nullable NSString *)cancelButtonTitle
-                                            otherButtonTitles:(nullable NSString *)otherButtonTitles, ... NS_REQUIRES_NIL_TERMINATION;
+                                            otherButtonTitles:(nullable NSString *)otherButtonTitles, ... NS_REQUIRES_NIL_TERMINATION NS_EXTENSION_UNAVAILABLE_IOS("Not available in app extensions.");
 
 @end
 

UIKit+AFNetworking/UIAlertView+AFNetworking.m

@@ -21,7 +21,7 @@
 
 #import "UIAlertView+AFNetworking.h"
 
-#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && !defined(AF_APP_EXTENSIONS)
+#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)
 
 #import "AFURLConnectionOperation.h"