swift4/ShaarliOS/3rd/KeyValueObserver.m

   1 //  https://github.com/objcio/issue-7-lab-color-space-explorer/blob/9551c8b6f67dd46eca91d93c0437d10ff9ee4eed/Lab%20Color%20Space%20Explorer/KeyValueObserver.m
   2 //  KeyValueObserver.m
   3 //  Lab Color Space Explorer
   4 //
   5 //  Created by Daniel Eggert on 01/12/2013.
   6 //  Copyright (c) 2013 objc.io. All rights reserved.
   7 //
   8
   9 #import "KeyValueObserver.h"
  10
  11 //
  12 // Created by chris on 7/24/13.
  13 //
  14
  15 #import "KeyValueObserver.h"
  16
  17 @interface KeyValueObserver ()
  18 @property (nonatomic, weak) id observedObject;
  19 @property (nonatomic, copy) NSString* keyPath;
  20 @end
  21
  22 @implementation KeyValueObserver
  23
  24 - (id)initWithObject:(id)object keyPath:(NSString*)keyPath target:(id)target selector:(SEL)selector options:(NSKeyValueObservingOptions)options;
  25 {
  26     if (object == nil) {
  27         return nil;
  28     }
  29     NSParameterAssert(target != nil);
  30     NSParameterAssert([target respondsToSelector:selector]);
  31     self = [super init];
  32     if (self) {
  33         self.target = target;
  34         self.selector = selector;
  35         self.observedObject = object;
  36         self.keyPath = keyPath;
  37         [object addObserver:self forKeyPath:keyPath options:options context:(__bridge void *)(self)];
  38     }
  39     return self;
  40 }
  41
  42 + (NSObject *)observeObject:(id)object keyPath:(NSString*)keyPath target:(id)target selector:(SEL)selector __attribute__((warn_unused_result));
  43 {
  44     return [self observeObject:object keyPath:keyPath target:target selector:selector options:0];
  45 }
  46
  47 + (NSObject *)observeObject:(id)object keyPath:(NSString*)keyPath target:(id)target selector:(SEL)selector options:(NSKeyValueObservingOptions)options __attribute__((warn_unused_result));
  48 {
  49     return [[self alloc] initWithObject:object keyPath:keyPath target:target selector:selector options:options];
  50 }
  51
  52 - (void)observeValueForKeyPath:(NSString*)keyPath ofObject:(id)object change:(NSDictionary*)change context:(void*)context
  53 {
  54     if (context == (__bridge void *)(self)) {
  55         [self didChange:change];
  56     }
  57 }
  58
  59 - (void)didChange:(NSDictionary *)change;
  60 {
  61     id strongTarget = self.target;
  62 #pragma clang diagnostic push
  63 #pragma clang diagnostic ignored "-Warc-performSelector-leaks"
  64     [strongTarget performSelector:self.selector withObject:change];
  65 #pragma clang diagnostic pop
  66 }
  67
  68 - (void)dealloc;
  69 {
  70     [self.observedObject removeObserver:self forKeyPath:self.keyPath];
  71 }
  72
  73 @end