gistfile1.txt

//
//  NSNotificationCenter+RSLAdditions.h
//
//  Created by Doug Russell
//  Copyright (c) 2012 Doug Russell. All rights reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

#import <Foundation/Foundation.h>

@interface NSNotificationCenter (RSLAdditions)

- (id)rsl_addObserver:(id)observer selector:(SEL)selector name:(NSString *)name object:(id)object;

@end


//
//  NSNotificationCenter+RSLAdditions.m
//
//  Created by Doug Russell
//  Copyright (c) 2012 Doug Russell. All rights reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

#import "NSNotificationCenter+RSLAdditions.h"
#import <objc/runtime.h>

@protocol RSLObserverWatcherDelegate <NSObject>
- (void)rsl_shouldRemoveObserver:(id)observer;
@end

@interface RSLObserverWatcher : NSObject
@property (weak) id<RSLObserverWatcherDelegate> delegate;
@property id observer;
@end

@interface NSNotificationCenter (RSLObserverWatcherDelegate) <RSLObserverWatcherDelegate>
@end

@implementation NSNotificationCenter (RSLAdditions)

- (id)rsl_addObserver:(id)observer selector:(SEL)selector name:(NSString *)name object:(id)object
{
	NSMethodSignature *signature = [observer methodSignatureForSelector:selector];
	if (signature == nil)
	{
		NSLog(@"%@ is an invalid selector", NSStringFromSelector(selector));
		return nil;
	}
	bool validSelector = false;
	NSUInteger argCount = [signature numberOfArguments];
	if (argCount == 2)
	{
		// - (void)foo;
		validSelector = true;
	}
	else if (argCount == 3)
	{
		// - (void)foo:(NSNotification *)note;
		validSelector = true;
	}
	if (!validSelector)
	{
		NSLog(@"%@ is an invalid notification selector", NSStringFromSelector(selector));
		return nil;
	}
	__weak id weakObserver = observer;
	id token = [self addObserverForName:name object:object queue:nil usingBlock:^(NSNotification *note) {
		id strongObserver = weakObserver;
		if (strongObserver)
		{
			NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];
			[invocation setTarget:strongObserver];
			[invocation setSelector:selector];
			if (argCount == 3)
				[invocation setArgument:&note atIndex:2];
			[invocation invoke];
		}
	}];
	RSLObserverWatcher *watcher = [RSLObserverWatcher new];
	watcher.delegate = self;
	watcher.observer = token;
static const void * key = @"RSLObserverWatcher";
	objc_setAssociatedObject(observer, key, watcher, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
	return token;
}

@end

@implementation RSLObserverWatcher

- (void)dealloc
{
	[self.delegate rsl_shouldRemoveObserver:self.observer];
}

@end

@implementation NSNotificationCenter (RSLObserverWatcherDelegate)

- (void)rsl_shouldRemoveObserver:(id)observer
{
	NSLog(@"%@ %@ %@", NSStringFromClass([self class]), NSStringFromSelector(_cmd), observer);
	[self removeObserver:observer];
}

@end