121 lines
4.6 KiB
Objective-C
121 lines
4.6 KiB
Objective-C
//
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// NSObject+RACPropertySubscribing.h
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// ReactiveObjC
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//
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// Created by Josh Abernathy on 3/2/12.
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// Copyright (c) 2012 GitHub, Inc. All rights reserved.
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//
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#import <Foundation/Foundation.h>
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#import <ReactiveObjC/RACEXTKeyPathCoding.h>
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#import "RACmetamacros.h"
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/// Creates a signal which observes `KEYPATH` on `TARGET` for changes.
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///
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/// In either case, the observation continues until `TARGET` _or self_ is
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/// deallocated. If any intermediate object is deallocated instead, it will be
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/// assumed to have been set to nil.
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///
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/// Make sure to `@strongify(self)` when using this macro within a block! The
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/// macro will _always_ reference `self`, which can silently introduce a retain
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/// cycle within a block. As a result, you should make sure that `self` is a weak
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/// reference (e.g., created by `@weakify` and `@strongify`) before the
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/// expression that uses `RACObserve`.
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///
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/// Examples
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///
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/// // Observes self, and doesn't stop until self is deallocated.
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/// RACSignal *selfSignal = RACObserve(self, arrayController.items);
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///
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/// // Observes the array controller, and stops when self _or_ the array
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/// // controller is deallocated.
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/// RACSignal *arrayControllerSignal = RACObserve(self.arrayController, items);
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///
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/// // Observes obj.arrayController, and stops when self _or_ the array
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/// // controller is deallocated.
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/// RACSignal *signal2 = RACObserve(obj.arrayController, items);
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///
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/// @weakify(self);
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/// RACSignal *signal3 = [anotherSignal flattenMap:^(NSArrayController *arrayController) {
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/// // Avoids a retain cycle because of RACObserve implicitly referencing
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/// // self.
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/// @strongify(self);
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/// return RACObserve(arrayController, items);
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/// }];
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///
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/// Returns a signal which sends the current value of the key path on
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/// subscription, then sends the new value every time it changes, and sends
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/// completed if self or observer is deallocated.
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#define _RACObserve(TARGET, KEYPATH) \
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({ \
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__weak id target_ = (TARGET); \
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[target_ rac_valuesForKeyPath:@keypath(TARGET, KEYPATH) observer:self]; \
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})
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#if __clang__ && (__clang_major__ >= 8)
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#define RACObserve(TARGET, KEYPATH) _RACObserve(TARGET, KEYPATH)
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#else
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#define RACObserve(TARGET, KEYPATH) \
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({ \
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_Pragma("clang diagnostic push") \
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_Pragma("clang diagnostic ignored \"-Wreceiver-is-weak\"") \
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_RACObserve(TARGET, KEYPATH) \
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_Pragma("clang diagnostic pop") \
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})
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#endif
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@class RACDisposable;
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@class RACTwoTuple<__covariant First, __covariant Second>;
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@class RACSignal<__covariant ValueType>;
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NS_ASSUME_NONNULL_BEGIN
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@interface NSObject (RACPropertySubscribing)
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/// Creates a signal to observe the value at the given key path.
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///
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/// The initial value is sent on subscription, the subsequent values are sent
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/// from whichever thread the change occured on, even if it doesn't have a valid
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/// scheduler.
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///
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/// Returns a signal that immediately sends the receiver's current value at the
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/// given keypath, then any changes thereafter.
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#if OS_OBJECT_HAVE_OBJC_SUPPORT
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- (RACSignal *)rac_valuesForKeyPath:(NSString *)keyPath observer:(__weak NSObject *)observer;
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#else
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// Swift builds with OS_OBJECT_HAVE_OBJC_SUPPORT=0 for Playgrounds and LLDB :(
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- (RACSignal *)rac_valuesForKeyPath:(NSString *)keyPath observer:(NSObject *)observer;
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#endif
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/// Creates a signal to observe the changes of the given key path.
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///
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/// The initial value is sent on subscription if `NSKeyValueObservingOptionInitial` is set.
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/// The subsequent values are sent from whichever thread the change occured on,
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/// even if it doesn't have a valid scheduler.
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///
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/// Returns a signal that sends tuples containing the current value at the key
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/// path and the change dictionary for each KVO callback.
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#if OS_OBJECT_HAVE_OBJC_SUPPORT
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- (RACSignal<RACTwoTuple<id, NSDictionary *> *> *)rac_valuesAndChangesForKeyPath:(NSString *)keyPath options:(NSKeyValueObservingOptions)options observer:(__weak NSObject *)observer;
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#else
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- (RACSignal<RACTwoTuple<id, NSDictionary *> *> *)rac_valuesAndChangesForKeyPath:(NSString *)keyPath options:(NSKeyValueObservingOptions)options observer:(NSObject *)observer;
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#endif
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@end
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NS_ASSUME_NONNULL_END
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#define RACAble(...) \
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metamacro_if_eq(1, metamacro_argcount(__VA_ARGS__)) \
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(_RACAbleObject(self, __VA_ARGS__)) \
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(_RACAbleObject(__VA_ARGS__))
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#define _RACAbleObject(object, property) [object rac_signalForKeyPath:@keypath(object, property) observer:self]
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#define RACAbleWithStart(...) \
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metamacro_if_eq(1, metamacro_argcount(__VA_ARGS__)) \
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(_RACAbleWithStartObject(self, __VA_ARGS__)) \
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(_RACAbleWithStartObject(__VA_ARGS__))
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#define _RACAbleWithStartObject(object, property) [object rac_signalWithStartingValueForKeyPath:@keypath(object, property) observer:self]
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