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featherVoice/Pods/ReactiveObjC/ReactiveObjC/NSObject+RACPropertySubscribing.m
2025-08-08 10:49:36 +08:00

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2.8 KiB
Objective-C

//
// NSObject+RACPropertySubscribing.m
// ReactiveObjC
//
// Created by Josh Abernathy on 3/2/12.
// Copyright (c) 2012 GitHub, Inc. All rights reserved.
//
#import "NSObject+RACPropertySubscribing.h"
#import <ReactiveObjC/RACEXTScope.h>
#import "NSObject+RACDeallocating.h"
#import "NSObject+RACDescription.h"
#import "NSObject+RACKVOWrapper.h"
#import "RACCompoundDisposable.h"
#import "RACDisposable.h"
#import "RACKVOTrampoline.h"
#import "RACSubscriber.h"
#import "RACSignal+Operations.h"
#import "RACTuple.h"
#import <libkern/OSAtomic.h>
@implementation NSObject (RACPropertySubscribing)
- (RACSignal *)rac_valuesForKeyPath:(NSString *)keyPath observer:(__weak NSObject *)observer {
return [[[self
rac_valuesAndChangesForKeyPath:keyPath options:NSKeyValueObservingOptionInitial observer:observer]
map:^(RACTuple *value) {
// -map: because it doesn't require the block trampoline that -reduceEach: uses
return value[0];
}]
setNameWithFormat:@"RACObserve(%@, %@)", RACDescription(self), keyPath];
}
- (RACSignal *)rac_valuesAndChangesForKeyPath:(NSString *)keyPath options:(NSKeyValueObservingOptions)options observer:(__weak NSObject *)weakObserver {
NSObject *strongObserver = weakObserver;
keyPath = [keyPath copy];
NSRecursiveLock *objectLock = [[NSRecursiveLock alloc] init];
objectLock.name = @"org.reactivecocoa.ReactiveObjC.NSObjectRACPropertySubscribing";
__weak NSObject *weakSelf = self;
RACSignal *deallocSignal = [[RACSignal
zip:@[
self.rac_willDeallocSignal,
strongObserver.rac_willDeallocSignal ?: [RACSignal never]
]]
doCompleted:^{
// Forces deallocation to wait if the object variables are currently
// being read on another thread.
[objectLock lock];
@onExit {
[objectLock unlock];
};
}];
return [[[RACSignal
createSignal:^ RACDisposable * (id<RACSubscriber> subscriber) {
// Hold onto the lock the whole time we're setting up the KVO
// observation, because any resurrection that might be caused by our
// retaining below must be balanced out by the time -dealloc returns
// (if another thread is waiting on the lock above).
[objectLock lock];
@onExit {
[objectLock unlock];
};
__strong NSObject *observer __attribute__((objc_precise_lifetime)) = weakObserver;
__strong NSObject *self __attribute__((objc_precise_lifetime)) = weakSelf;
if (self == nil) {
[subscriber sendCompleted];
return nil;
}
return [self rac_observeKeyPath:keyPath options:options observer:observer block:^(id value, NSDictionary *change, BOOL causedByDealloc, BOOL affectedOnlyLastComponent) {
[subscriber sendNext:RACTuplePack(value, change)];
}];
}]
takeUntil:deallocSignal]
setNameWithFormat:@"%@ -rac_valueAndChangesForKeyPath: %@ options: %lu observer: %@", RACDescription(self), keyPath, (unsigned long)options, RACDescription(strongObserver)];
}
@end