ReactiveCocoa v2.5 源码解析之架构总览

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// 代理方法
[[self
rac_signalForSelector:@selector(webViewDidStartLoad:)
fromProtocol:@protocol(UIWebViewDelegate)]
subscribeNext:^(id x) {
// 实现 webViewDidStartLoad: 代理方法
}];

// target-action
[[self.avatarButton
rac_signalForControlEvents:UIControlEventTouchUpInside]
subscribeNext:^(UIButton *avatarButton) {
// avatarButton 被点击了
}];

// 通知
[[[NSNotificationCenter defaultCenter]
rac_addObserverForName:kReachabilityChangedNotification object:nil]
subscribeNext:^(NSNotification *notification) {
// 收到 kReachabilityChangedNotification 通知
}];

// KVO
[RACObserve(self, username) subscribeNext:^(NSString *username) {
// 用户名发生了变化
}];

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[[[RACSignal
combineLatest:@[ RACObserve(self, username), RACObserve(self, password) ]
reduce:^(NSString *username, NSString *password) {
return @(username.length > 0 && password.length > 0);
}]
distinctUntilChanged]
subscribeNext:^(NSNumber *valid) {
if (valid.boolValue) {
// 用户名和密码合法，登录按钮可用
} else {
// 用户名或密码不合法，登录按钮不可用
}
}];

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/// An abstract class representing any stream of values.
///
/// This class represents a monad, upon which many stream-based operations can
/// be built.
///
/// When subclassing RACStream, only the methods in the main @interface body need
/// to be overridden.
@interface RACStream : NSObject

/// Lifts `value` into the stream monad.
///
/// Returns a stream containing only the given value.
+ (instancetype)return:(id)value;

/// Lazily binds a block to the values in the receiver.
///
/// This should only be used if you need to terminate the bind early, or close
/// over some state. -flattenMap: is more appropriate for all other cases.
///
/// block - A block returning a RACStreamBindBlock. This block will be invoked
///         each time the bound stream is re-evaluated. This block must not be
///         nil or return nil.
///
/// Returns a new stream which represents the combined result of all lazy
/// applications of `block`.
- (instancetype)bind:(RACStreamBindBlock (^)(void))block;

@end

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- (RACDisposable *)subscribe:(id<RACSubscriber>)subscriber {
NSCAssert(NO, @"This method must be overridden by subclasses");
return nil;
}

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[self.viewModel.errors subscribeNext:^(NSError *error) {
// 错误处理逻辑
}

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[[RACSignal
merge:@[
self.requestReadmeMarkdownCommand.errors,
self.requestBlobCommand.errors,
self.requestReadmeHTMLCommand.errors
]]
subscribe:self.errors];

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/// Represents an immutable sequence of values. Unless otherwise specified, the
/// sequences' values are evaluated lazily on demand. Like Cocoa collections,
/// sequences cannot contain nil.
///
/// Most inherited RACStream methods that accept a block will execute the block
/// _at most_ once for each value that is evaluated in the returned sequence.
/// Side effects are subject to the behavior described in
/// +sequenceWithHeadBlock:tailBlock:.
///
/// Implemented as a class cluster. A minimal implementation for a subclass
/// consists simply of -head and -tail.
@interface RACSequence : RACStream <NSCoding, NSCopying, NSFastEnumeration>

/// The first object in the sequence, or nil if the sequence is empty.
///
/// Subclasses must provide an implementation of this method.
@property (nonatomic, strong, readonly) id head;

/// All but the first object in the sequence, or nil if the sequence is empty.
///
/// Subclasses must provide an implementation of this method.
@property (nonatomic, strong, readonly) RACSequence *tail;

@end

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NSMutableArray *results = [NSMutableArray array];
for (NSString *str in strings) {
if (str.length < 2) {
continue;
}

NSString *newString = [str stringByAppendingString:@"foobar"];
[results addObject:newString];
}

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RACSequence *results = [[strings.rac_sequence
filter:^ BOOL (NSString *str) {
return str.length >= 2;
}]
map:^(NSString *str) {
return [str stringByAppendingString:@"foobar"];
}];

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- (NSUInteger)countByEnumeratingWithState:(NSFastEnumerationState *)state objects:(id __unsafe_unretained [])buffer count:(NSUInteger)len;

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/// Represents any object which can directly receive values from a RACSignal.
///
/// You generally shouldn't need to implement this protocol. +[RACSignal
/// createSignal:], RACSignal's subscription methods, or RACSubject should work
/// for most uses.
///
/// Implementors of this protocol may receive messages and values from multiple
/// threads simultaneously, and so should be thread-safe. Subscribers will also
/// be weakly referenced so implementations must allow that.
@protocol RACSubscriber <NSObject>

@required

/// Sends the next value to subscribers.
///
/// value - The value to send. This can be `nil`.
- (void)sendNext:(id)value;

/// Sends the error to subscribers.
///
/// error - The error to send. This can be `nil`.
///
/// This terminates the subscription, and invalidates the subscriber (such that
/// it cannot subscribe to anything else in the future).
- (void)sendError:(NSError *)error;

/// Sends completed to subscribers.
///
/// This terminates the subscription, and invalidates the subscriber (such that
/// it cannot subscribe to anything else in the future).
- (void)sendCompleted;

/// Sends the subscriber a disposable that represents one of its subscriptions.
///
/// A subscriber may receive multiple disposables if it gets subscribed to
/// multiple signals; however, any error or completed events must terminate _all_
/// subscriptions.
- (void)didSubscribeWithDisposable:(RACCompou
2202e
ndDisposable *)disposable;

@end

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- (void)sendNext:(id)value {
if (self.disposable.disposed) return;
[self.innerSubscriber sendNext:value];
}

- (void)sendError:(NSError *)error {
if (self.disposable.disposed) return;
[self.innerSubscriber sendError:error];
}

- (void)sendCompleted {
if (self.disposable.disposed) return;
[self.innerSubscriber sendCompleted];
}

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- (RACDisposable *)scheduleRecursiveBlock:(RACSchedulerRecursiveBlock)recursiveBlock;