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KeyPathObserver.m
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125 lines (100 loc) · 3.7 KB
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//
// KeyPathObserver.m
//
// Created by Olivier Halligon on 24/09/12.
//
//
#import "KeyPathObserver.h"
#import <objc/runtime.h>
//////////////////////////////////////////////////////////////////////////////////////////
#pragma mark - KeyPathObserver Helper Class Interface
@interface KeyPathObserver : NSObject
+(KeyPathObserver*)observerForObject:(id)object;
-(void)onKeyPathValueChange:(NSString*)keyPath execute:(KeyPathObserverActionBlock)block;
-(void)removeAllObservedKeyPaths;
@property(nonatomic, retain) NSMutableDictionary* blocksMappings;
@property(nonatomic, assign) id targetObject;
@end
//////////////////////////////////////////////////////////////////////////////////////////
#pragma mark - KeyPathObserver Category Implementation
@implementation NSObject (KeyPathObserver)
-(void)onKeyPathValueChange:(NSString*)keyPath execute:(KeyPathObserverActionBlock)block
{
[[KeyPathObserver observerForObject:self] onKeyPathValueChange:keyPath execute:block];
}
-(NSArray*)observedKeyPaths
{
return [[KeyPathObserver observerForObject:self].blocksMappings allKeys];
}
-(void)removeAllObservedKeyPaths
{
[[KeyPathObserver observerForObject:self] removeAllObservedKeyPaths];
}
@end
//////////////////////////////////////////////////////////////////////////////////////////
#pragma mark - KeyPathObserver Helper Class Implementation
@implementation KeyPathObserver
@synthesize blocksMappings = _blocksMappings;
@synthesize targetObject = _targetObject;
static char kKeyPathObserverContext;
+(KeyPathObserver*)observerForObject:(id)object
{
KeyPathObserver* observer = nil;
if (object)
{
observer = (KeyPathObserver*)objc_getAssociatedObject(object, &kKeyPathObserverContext);
if (!observer)
{
observer = [[[self alloc] init] autorelease];
observer.blocksMappings = [NSMutableDictionary dictionary];
observer.targetObject = object;
objc_setAssociatedObject(object, &kKeyPathObserverContext, observer, OBJC_ASSOCIATION_RETAIN);
}
}
return observer;
}
-(void)onKeyPathValueChange:(NSString*)keyPath execute:(KeyPathObserverActionBlock)block
{
if (block)
{
NSMutableArray* blocks = [self.blocksMappings objectForKey:keyPath];
if (!blocks)
{
blocks = [NSMutableArray array];
[self.blocksMappings setObject:blocks forKey:keyPath];
NSKeyValueObservingOptions options = (NSKeyValueObservingOptionOld|NSKeyValueObservingOptionNew);
[self.targetObject addObserver:self forKeyPath:keyPath options:options context:&kKeyPathObserverContext];
}
[blocks addObject:[[block copy] autorelease]];
} else {
[self.targetObject removeObserver:self forKeyPath:keyPath context:&kKeyPathObserverContext];
[self.blocksMappings removeObjectForKey:keyPath];
}
}
-(void)removeAllObservedKeyPaths
{
NSEnumerator* reverseEnum = [self.blocksMappings.allKeys reverseObjectEnumerator];
for(NSString* keyPath in reverseEnum)
{
[self.targetObject removeObserver:self forKeyPath:keyPath context:&kKeyPathObserverContext];
}
[_blocksMappings removeAllObjects];
}
-(void)dealloc
{
// Remove observers
[self removeAllObservedKeyPaths];
[_blocksMappings release];
[super dealloc];
}
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
NSMutableArray* blocks = [self.blocksMappings objectForKey:keyPath];
for(KeyPathObserverActionBlock block in blocks)
{
id old = [change objectForKey:NSKeyValueChangeOldKey];
id new = [change objectForKey:NSKeyValueChangeNewKey];
block(object, keyPath, old, new);
}
}
@end