RunLoop原理以及深度实现，RunLoop相关的部分Foundation API

前几个月没事，实现了下 iOS （Mac OS ） 的 NSRunLoop，github地址是 https://github.com/wuyunfeng/LightWeightRunLoop.git，欢迎大家 star 多多支持，喜欢研究底层API的朋友可以fork， pull-request. 其实iOS的RunLoop也就那么一回事，没什么可神秘的。
markdown文档 我是用英文写的，也挺好理解的。

转载务必请注明出处

Overview:

Each NSThread object, excluding the application’s main thread, can own an LWRunLoop object. You can get the current thread’s LWRunLoop, through the class method currentLWRunLoop. Subsequently code snippet shows how configure LWRunLoop for NSThread and make the NSThread _lwRunLoopThread entering into Event-Driver-Mode:

 NSThread *_lwRunLoopThread = [[NSThread alloc] initWithTarget:self selector:@selector(lightWeightRunloopThreadEntryPoint:) object:nil];    - (void)lightWeightRunloopThreadEntryPoint:(id)data {@autoreleasepool {    LWRunLoop *looper = [LWRunLoop currentLWRunLoop];    [looper run];    // or    //[[LWRunLoop currentLWRunLoop] run];    }}

To enqueue a selector to be performed on a different thread than your own

you can use the category of NSObject(post)

-(void)postSelector:(SEL)aSelector onThread:(NSThread *)thread withObject:(id)arg;

such as:

  [self postSelector:@selector(execute) onThread:_lwRunLoopThread withObject:nil];

To schedule a selector to be executed at some point in the future

you can use the category of NSObject(post)

-(void)postSelector:(SEL)aSelector onThread:(NSThread *)thread withObject:(id)arg afterDelay:(NSInteger)delay;

such as:

[self postSelector:@selector(execute) onThread:_lwRunLoopThread withObject:nil afterDelay:1000];

You use the LWTimer class to create timer objects or, more simply, timers.

A timer waits until a certain time interval has elapsed and then fires, sending a specified message to a target object.

+(LWTimer * _Nonnull)scheduledLWTimerWithTimeInterval:(NSTimeInterval)interval target:(nonnull id)aTarget selector:(nonnull SEL)aSelector userInfo:(nullable id)userInfo repeats:(BOOL)yesOrNo;

+(LWTimer * _Nonnull)timerWithTimeInterval:(NSTimeInterval)interval target:(nonnull id)aTarget selector:(nonnull SEL)aSelector userInfo:(nullable id)userInfo repeats:(BOOL)yesOrNo;

fire the LWTimer using - (void)fire and invalidate the LWTimer using - (void)invalidate

For example:

run the - (void)genernateLWTimer on _lwRunLoopThread:

[self postSelector:@selector(genernateLWTimer) onThread:_lwRunLoopThread withObject:nil];- (void)genernateLWTimer{    _count = 0;    LWTimer *timer = [LWTimer timerWithTimeInterval:1000 target:self selector:@selector(bindLWTimerWithSelector:) userInfo:nil repeats:YES];[timer fire];   //gTimer = [LWTimer scheduledLWTimerWithTimeInterval:2000 target:self selector:@selector(bindLWTimerWithSelector:) userInfo:nil repeats:YES];}

the selector for LWTimer to be executed:

- (void)bindLWTimerWithSelector:(LWTimer *)timer{    _count++;    NSLog(@"* [ LWTimer : %@ performSelector: ( %@ ) on Thread : %@ ] *", [self class], NSStringFromSelector(_cmd), [NSThread currentThread].name);    if (_count == 4) {        [timer invalidate];    }}   

An LWURLConnection object lets you load the contents of a URL by providing a URL request object.

Step1: Perform LWURLConnection on _lwRunLoopThread:

- (void)executeURLConnection:(UIButton *)button{   [self postSelector:@selector(performURLConnectionOnRunLoopThread) onThread:_lwRunLoopThread withObject:nil];}

Step2: Create LWURLConnection, schedule LWURLConnection to _lwRunLoopThread such as following code snippet:

- (void)performURLConnectionOnRunLoopThread{    NSLog(@"[%@ %@]", [self class], NSStringFromSelector(_cmd));    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://192.168.1.8:8888/post.php"]];   request.HTTPMethod = @"POST";   NSString *content = @"name=john&address=beijing&mobile=140005";   request.HTTPBody = [content dataUsingEncoding:NSUTF8StringEncoding];   LWURLConnection *conn = [[LWURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];   [conn scheduleInRunLoop:_lwRunLoopThread.looper];   [conn start];}

Step3: Implement the delegate methods on Receiver:

@protocol LWURLConnectionDataDelegate <NSObject>- (void)lw_connection:(LWURLConnection * _Nonnull)connection didReceiveData:(NSData * _Nullable)data;- (void)lw_connection:(LWURLConnection * _Nonnull)connection didFailWithError:(NSError * _Nullable)error;- (void)lw_connectionDidFinishLoading:(LWURLConnection * _Nonnull)connection;@end

Step4: You can use LWURLResponse to format Http response

LWURLResponse *response = [[LWURLResponse alloc] initWithData:_responseData];

If you want to join me, cantact me with [e-mail] or fork this project https://github.com/wuyunfeng/LightWeightRunLoop and create a pull-request