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杭城小刘
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Chapter1 - iOS/1.39.md
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770
Chapter1 - iOS/1.39.md
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# 监听 RunLoop
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```Objective-C
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//给 RunLoop 添加监听者
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- (void)testRunLoopObserver{
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//创建监听者
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// CFRunLoopObserverCreate(CFAllocatorGetDefault(), kCFRunLoopAllActivities, <#Boolean repeats#>, <#CFIndex order#>, <#CFRunLoopObserverCallBack callout#>, <#CFRunLoopObserverContext *context#>)
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/*
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创建监听对象
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参数1:分配内存空间
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参数2:要监听的状态 kCFRunLoopAllActivities ：所有状态
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参数3:是否要持续监听
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参数4:优先级
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参数5:回调
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*/
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CFRunLoopObserverRef oberver = CFRunLoopObserverCreateWithHandler(CFAllocatorGetDefault(), kCFRunLoopAllActivities, YES, 0, ^(CFRunLoopObserverRef observer, CFRunLoopActivity activity) {
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switch (activity) {
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case kCFRunLoopEntry:
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NSLog(@"RunLoop 闪亮登场");
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break;
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case kCFRunLoopBeforeTimers:
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NSLog(@"RunLoop 大哥要处理 Timer 了");
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break;
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case kCFRunLoopBeforeSources:
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//Source 有2种。Source0:非基于 port 的，用户主动触发的事件。Source1:基于 port，通过内核和其它线程互相发送消息
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NSLog(@"RunLoop 大哥要处理 Source 了");
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break;
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case kCFRunLoopBeforeWaiting:
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NSLog(@"RunLoop 大哥没事干要睡觉了");
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break;
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case kCFRunLoopAfterWaiting:
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NSLog(@"");
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NSLog(@"RunLoop 大哥终于等到有缘人了，要醒来开始干活了");
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break;
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case kCFRunLoopExit:
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NSLog(@"RunLoop 大哥要退出离开了");
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break;
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default:
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break;
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}
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});
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/*
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参数1:要监听哪个RunLoop
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参数2:监听者
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参数3:要监听 RunLoop 在哪种运行模式下的状态
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*/
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CFRunLoopAddObserver(CFRunLoopGetCurrent(), oberver, kCFRunLoopDefaultMode);
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//CoreFoundation 的内存管理：凡是带有 Create、Copy、Retain等字眼的函数创建出来的对象都需要在最后调用 release
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CFRelease(oberver);
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[NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(wakeupRunLoop) userInfo:nil repeats:YES];
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}
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//等到 RunLoop 休眠后，5秒钟叫醒 RunLoop
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- (void)wakeupRunLoop{
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NSLog(@"%s",__func__);
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}
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/*
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2018-08-01 11:23:49.401626+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Timer 了
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2018-08-01 11:23:49.401950+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Source 了
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2018-08-01 11:23:49.402326+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Timer 了
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2018-08-01 11:23:49.402509+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Source 了
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2018-08-01 11:23:49.402721+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Timer 了
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2018-08-01 11:23:49.402855+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Source 了
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2018-08-01 11:23:49.403080+0800 RunLoop[38148:1994974] RunLoop 大哥没事干要睡觉了
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2018-08-01 11:23:49.459238+0800 RunLoop[38148:1994974]
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2018-08-01 11:23:49.459512+0800 RunLoop[38148:1994974] RunLoop 大哥终于等到有缘人了，要醒来开始干活了
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2018-08-01 11:23:49.459740+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Timer 了
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2018-08-01 11:23:49.459932+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Source 了
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2018-08-01 11:23:49.460431+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Timer 了
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2018-08-01 11:23:49.460607+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Source 了
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2018-08-01 11:23:49.460775+0800 RunLoop[38148:1994974] RunLoop 大哥没事干要睡觉了
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2018-08-01 11:23:49.880631+0800 RunLoop[38148:1994974]
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2018-08-01 11:23:49.880867+0800 RunLoop[38148:1994974] RunLoop 大哥终于等到有缘人了，要醒来开始干活了
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2018-08-01 11:23:49.881530+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Timer 了
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2018-08-01 11:23:49.881699+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Source 了
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2018-08-01 11:23:49.881870+0800 RunLoop[38148:1994974] RunLoop 大哥没事干要睡觉了
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2018-08-01 11:23:54.402263+0800 RunLoop[38148:1994974]
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2018-08-01 11:23:54.402562+0800 RunLoop[38148:1994974] RunLoop 大哥终于等到有缘人了，要醒来开始干活了
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2018-08-01 11:23:54.402773+0800 RunLoop[38148:1994974] -[ViewController wakeupRunLoop]
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2018-08-01 11:23:54.403081+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Timer 了
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2018-08-01 11:23:54.403245+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Source 了
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2018-08-01 11:23:54.403476+0800 RunLoop[38148:1994974] RunLoop 大哥没事干要睡觉了
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2018-08-01 11:23:59.402151+0800 RunLoop[38148:1994974]
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2018-08-01 11:23:59.402511+0800 RunLoop[38148:1994974] RunLoop 大哥终于等到有缘人了，要醒来开始干活了
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2018-08-01 11:23:59.402687+0800 RunLoop[38148:1994974] -[ViewController wakeupRunLoop]
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2018-08-01 11:23:59.402913+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Timer 了
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2018-08-01 11:23:59.403037+0800 RunLoop[38148:1994974] RunLoop 大哥要处理 Source 了
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2018-08-01 11:23:59.403156+0800 RunLoop[38148:1994974] RunLoop 大哥没事干要睡觉了
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```
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上个实验是在主线程对 RunLoop 进行的监听，但是由于是主线程是由系统创建的，所以系统也创建了对应的主 RunLoop，所以我们看不到 RunLoop 创建的状态，为了模拟完整的状态，我们开启子线程，在子线程中模拟
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```objective-c
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- (void)testRunLoopObserverOnSubThread{
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//创建并发队列
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dispatch_queue_t queue = dispatch_queue_create("com.lbp.testRunLoopOnSubThread", DISPATCH_QUEUE_CONCURRENT);
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//开启子线程
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dispatch_async(queue, ^{
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//1、获得当前线程下的 RunLoop
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CFRunLoopRef runloop = CFRunLoopGetCurrent();
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//2、为 RunLoop 创建观察者
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CFRunLoopObserverRef obersver = CFRunLoopObserverCreateWithHandler(CFAllocatorGetDefault(), kCFRunLoopAllActivities, YES, 0, ^(CFRunLoopObserverRef observer, CFRunLoopActivity activity) {
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switch (activity) {
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case kCFRunLoopEntry:
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NSLog(@"RunLoop 闪亮登场");
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break;
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case kCFRunLoopBeforeTimers:
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NSLog(@"RunLoop 大哥要处理 Timer 了");
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break;
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case kCFRunLoopBeforeSources:
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//Source 有2种。Source0:非基于 port 的，用户主动触发的事件。Source1:基于 port，通过内核和其它线程互相发送消息
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NSLog(@"RunLoop 大哥要处理 Source 了");
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break;
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case kCFRunLoopBeforeWaiting:
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NSLog(@"RunLoop 大哥没事干要睡觉了");
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break;
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case kCFRunLoopAfterWaiting:
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NSLog(@"");
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NSLog(@"RunLoop 大哥终于等到有缘人了，要醒来开始干活了");
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break;
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case kCFRunLoopExit:
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NSLog(@"RunLoop 大哥要退出离开了");
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break;
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default:
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break;
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}
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});
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//为了运行 RunLoop 必须触发事件
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[NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(wakeUpRunLoopOnSubThread) userInfo:nil repeats:NO];
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//3、为当前的 RunLoop 添加观察者
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CFRunLoopAddObserver(runloop, obersver, kCFRunLoopDefaultMode);
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//4、在 CoreFoundation 框架中， create、copy、retain 过的对象都必须在最后 release
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CFRelease(obersver);
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//5、在非主线程创建的 RunLoop 必须触发运行
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[[NSRunLoop currentRunLoop] run];
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});
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}
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- (void)wakeUpRunLoopOnSubThread{
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NSLog(@"%s",__func__);
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}
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/*
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2018-08-01 14:23:06.453282+0800 RunLoop[2376:115968] RunLoop 闪亮登场
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2018-08-01 14:23:06.453608+0800 RunLoop[2376:115968] RunLoop 大哥要处理 Timer 了
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2018-08-01 14:23:06.453781+0800 RunLoop[2376:115968] RunLoop 大哥要处理 Source 了
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2018-08-01 14:23:06.453982+0800 RunLoop[2376:115968] RunLoop 大哥没事干要睡觉了
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2018-08-01 14:23:08.458237+0800 RunLoop[2376:115968]
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||||
2018-08-01 14:23:08.458658+0800 RunLoop[2376:115968] RunLoop 大哥终于等到有缘人了，要醒来开始干活了
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2018-08-01 14:23:08.458894+0800 RunLoop[2376:115968] -[ViewController wakeUpRunLoopOnSubThread]
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2018-08-01 14:23:08.459082+0800 RunLoop[2376:115968] RunLoop 大哥要退出离开了
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*/
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```
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## RunLoop 内部运行原理
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- 图上左上角的 Input source 是早期 RunLoop 的分法，现在分法为：Source0 和 Source1。
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- Source0:非基于 port 的，用户主动触发的事件。
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- Source1:基于 port，通过内核和其它线程互相发送消息
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- RunLoop 我们不能自己手动创建，而是可以通过 [NSRunLoop currentRunLoop] 方法获取，类似于懒加载。系统底层的做法是在全局维护了一个字典，字典的 key 和 value 分别是当前的线程和线程对应的 RunLoop，如果新开辟的线程没有对应的 RunLoop，系统则为其创建 RunLoop，并将其写入字典（线程、为其创建的 RunLoop）
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运行流程图
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运行流程说明
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## RunLoopMode 的概念
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## 底层实现
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内部就是 do-while 的循环，在这个循环内部不断处理各种任务（Timer、Source、Observer）
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我们来看看苹果官方开源的 [CFRunLoop.c 文件](https://legacy.gitbook.com/book/fantasticlbp/knowledge-kit/edit#)。看几个关键函数的实现猜测下 RunLoop 的内部原理
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以下的代码都有注释说明
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**__CFRunLoopModeIsEmpty**
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此函数的作用就是判断这个 Mode 下面有没有 source0、source1、timer，只要存在就说明当前 Mode 不是空的，同时看看这个 Mode 是不是属于当前的 RunLoop
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```objective-c
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// expects rl and rlm locked
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static Boolean __CFRunLoopModeIsEmpty(CFRunLoopRef rl, CFRunLoopModeRef rlm, CFRunLoopModeRef previousMode) {
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CHECK_FOR_FORK();
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if (NULL == rlm) return true;
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#if DEPLOYMENT_TARGET_WINDOWS
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if (0 != rlm->_msgQMask) return false;
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#endif
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Boolean libdispatchQSafe = pthread_main_np() && ((HANDLE_DISPATCH_ON_BASE_INVOCATION_ONLY && NULL == previousMode) || (!HANDLE_DISPATCH_ON_BASE_INVOCATION_ONLY && 0 == _CFGetTSD(__CFTSDKeyIsInGCDMainQ)));
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if (libdispatchQSafe && (CFRunLoopGetMain() == rl) && CFSetContainsValue(rl->_commonModes, rlm->_name)) return false; // represents the libdispatch main queue
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// 判断时候有没有_sources0
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if (NULL != rlm->_sources0 && 0 < CFSetGetCount(rlm->_sources0)) return false;
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// 判断时候有没有_sources1
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if (NULL != rlm->_sources1 && 0 < CFSetGetCount(rlm->_sources1)) return false;
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// 判断时候有没有_timers
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if (NULL != rlm->_timers && 0 < CFArrayGetCount(rlm->_timers)) return false;
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||||
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struct _block_item *item = rl->_blocks_head;
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while (item) {
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||||
struct _block_item *curr = item;
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item = item->_next;
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Boolean doit = false;
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if (CFStringGetTypeID() == CFGetTypeID(curr->_mode)) {
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doit = CFEqual(curr->_mode, rlm->_name) || (CFEqual(curr->_mode, kCFRunLoopCommonModes) && CFSetContainsValue(rl->_commonModes, rlm->_name));
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||||
} else {
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||||
doit = CFSetContainsValue((CFSetRef)curr->_mode, rlm->_name) || (CFSetContainsValue((CFSetRef)curr->_mode, kCFRunLoopCommonModes) && CFSetContainsValue(rl->_commonModes, rlm->_name));
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}
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if (doit) return false;
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}
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return true;
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}
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```
|
||||
|
||||
|
||||
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||||
**CFRunLoopRun、CFRunLoopRunInMode**
|
||||
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||||
1、2个函数的作用分别是让 RunLoop 跑在 KCFRunLoopDefaultMode 下和特定的 Mode 下
|
||||
|
||||
2、2个函数本质上都是调用 CFRunLoopRunSpecific
|
||||
|
||||
```objective-c
|
||||
// 用DefaultMode启动
|
||||
void CFRunLoopRun(void) { /* DOES CALLOUT */
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||||
int32_t result;
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||||
do {
|
||||
result = CFRunLoopRunSpecific(CFRunLoopGetCurrent(), kCFRunLoopDefaultMode, 1.0e10, false);
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||||
CHECK_FOR_FORK();
|
||||
} while (kCFRunLoopRunStopped != result && kCFRunLoopRunFinished != result);
|
||||
}
|
||||
|
||||
|
||||
// 用指定的Mode启动，允许设置RunLoop超时时间
|
||||
SInt32 CFRunLoopRunInMode(CFStringRef modeName, CFTimeInterval seconds, Boolean returnAfterSourceHandled) { /* DOES CALLOUT */
|
||||
CHECK_FOR_FORK();
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||||
return CFRunLoopRunSpecific(CFRunLoopGetCurrent(), modeName, seconds, returnAfterSourceHandled);
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||||
}
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||||
```
|
||||
|
||||
|
||||
|
||||
**CFRunLoopRunSpecific**
|
||||
|
||||
参数1: RunLoop 对象。参数2:运行 Mode 名称。参数3:超时时间。参数4:主_CFRunLoopRun 会用到
|
||||
|
||||
```objective-c
|
||||
// RunLoop的实现
|
||||
SInt32 CFRunLoopRunSpecific(CFRunLoopRef rl, CFStringRef modeName, CFTimeInterval seconds, Boolean returnAfterSourceHandled) { /* DOES CALLOUT */
|
||||
CHECK_FOR_FORK();
|
||||
if (__CFRunLoopIsDeallocating(rl))
|
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return kCFRunLoopRunFinished;
|
||||
__CFRunLoopLock(rl);
|
||||
|
||||
|
||||
// 根据modeName找到对应mode
|
||||
CFRunLoopModeRef currentMode = __CFRunLoopFindMode(rl, modeName, false);
|
||||
|
||||
|
||||
// 判断mode里没有source/timer, 没有直接返回。
|
||||
if (NULL == currentMode || __CFRunLoopModeIsEmpty(rl, currentMode, rl->_currentMode)) {
|
||||
Boolean did = false;
|
||||
if (currentMode)
|
||||
__CFRunLoopModeUnlock(currentMode);
|
||||
__CFRunLoopUnlock(rl);
|
||||
return did ? kCFRunLoopRunHandledSource : kCFRunLoopRunFinished;
|
||||
}
|
||||
|
||||
|
||||
volatile _per_run_data *previousPerRun = __CFRunLoopPushPerRunData(rl);
|
||||
|
||||
|
||||
CFRunLoopModeRef previousMode = rl->_currentMode;
|
||||
rl->_currentMode = currentMode;
|
||||
int32_t result = kCFRunLoopRunFinished;
|
||||
|
||||
|
||||
if (currentMode->_observerMask & kCFRunLoopEntry )
|
||||
// 1. 通知 Observers: RunLoop 即将进入 loop
|
||||
__CFRunLoopDoObservers(rl, currentMode, kCFRunLoopEntry);
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// 进入loop
|
||||
result = __CFRunLoopRun(rl, currentMode, seconds, returnAfterSourceHandled, previousMode);
|
||||
|
||||
|
||||
if (currentMode->_observerMask & kCFRunLoopExit )
|
||||
// 10.通知 Observers: RunLoop 即将退出。
|
||||
__CFRunLoopDoObservers(rl, currentMode, kCFRunLoopExit);
|
||||
|
||||
|
||||
__CFRunLoopModeUnlock(currentMode);
|
||||
__CFRunLoopPopPerRunData(rl, previousPerRun);
|
||||
rl->_currentMode = previousMode;
|
||||
__CFRunLoopUnlock(rl);
|
||||
return result;
|
||||
}
|
||||
```
|
||||
|
||||
|
||||
|
||||
**__CFRunLoopDoObserver**
|
||||
|
||||
|
||||
|
||||
调用 Observer 回调
|
||||
|
||||
联想给 RunLoop 添加观察者，监听 RunLoop 状态。
|
||||
|
||||
```objective-c
|
||||
static void __CFRunLoopDoObservers(CFRunLoopRef rl, CFRunLoopModeRef rlm, CFRunLoopActivity activity) { /* DOES CALLOUT */
|
||||
CHECK_FOR_FORK();
|
||||
|
||||
|
||||
CFIndex cnt = rlm->_observers ? CFArrayGetCount(rlm->_observers) : 0;
|
||||
if (cnt < 1) return;
|
||||
|
||||
|
||||
/* Fire the observers */
|
||||
STACK_BUFFER_DECL(CFRunLoopObserverRef, buffer, (cnt <= 1024) ? cnt : 1);
|
||||
CFRunLoopObserverRef *collectedObservers = (cnt <= 1024) ? buffer : (CFRunLoopObserverRef *)malloc(cnt * sizeof(CFRunLoopObserverRef));
|
||||
CFIndex obs_cnt = 0;
|
||||
//遍历 rlm-> _observers,将元素放到 collectedObservers 数组中
|
||||
for (CFIndex idx = 0; idx < cnt; idx++) {
|
||||
CFRunLoopObserverRef rlo = (CFRunLoopObserverRef)CFArrayGetValueAtIndex(rlm->_observers, idx);
|
||||
if (0 != (rlo->_activities & activity) && __CFIsValid(rlo) && !__CFRunLoopObserverIsFiring(rlo)) {
|
||||
collectedObservers[obs_cnt++] = (CFRunLoopObserverRef)CFRetain(rlo);
|
||||
}
|
||||
}
|
||||
__CFRunLoopModeUnlock(rlm);
|
||||
__CFRunLoopUnlock(rl);
|
||||
for (CFIndex idx = 0; idx < obs_cnt; idx++) {
|
||||
CFRunLoopObserverRef rlo = collectedObservers[idx];
|
||||
__CFRunLoopObserverLock(rlo);
|
||||
if (__CFIsValid(rlo)) {
|
||||
Boolean doInvalidate = !__CFRunLoopObserverRepeats(rlo);
|
||||
__CFRunLoopObserverSetFiring(rlo);
|
||||
__CFRunLoopObserverUnlock(rlo);
|
||||
__CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__(rlo->_callout, rlo, activity, rlo->_context.info);
|
||||
if (doInvalidate) {
|
||||
CFRunLoopObserverInvalidate(rlo);
|
||||
}
|
||||
__CFRunLoopObserverUnsetFiring(rlo);
|
||||
} else {
|
||||
__CFRunLoopObserverUnlock(rlo);
|
||||
}
|
||||
CFRelease(rlo);
|
||||
}
|
||||
__CFRunLoopLock(rl);
|
||||
__CFRunLoopModeLock(rlm);
|
||||
|
||||
|
||||
if (collectedObservers != buffer) free(collectedObservers);
|
||||
}
|
||||
```
|
||||
|
||||
|
||||
|
||||
**__CFRunLoopRun**
|
||||
|
||||
```objective-c
|
||||
/* rl, rlm are locked on entrance and exit */
|
||||
static int32_t __CFRunLoopRun(CFRunLoopRef rl, CFRunLoopModeRef rlm, CFTimeInterval seconds, Boolean stopAfterHandle, CFRunLoopModeRef previousMode) {
|
||||
|
||||
|
||||
uint64_t startTSR = mach_absolute_time();
|
||||
|
||||
|
||||
if (__CFRunLoopIsStopped(rl)) {
|
||||
__CFRunLoopUnsetStopped(rl);
|
||||
return kCFRunLoopRunStopped;
|
||||
} else if (rlm->_stopped) {
|
||||
rlm->_stopped = false;
|
||||
return kCFRunLoopRunStopped;
|
||||
}
|
||||
|
||||
|
||||
mach_port_name_t dispatchPort = MACH_PORT_NULL;
|
||||
Boolean libdispatchQSafe = pthread_main_np() && ((HANDLE_DISPATCH_ON_BASE_INVOCATION_ONLY && NULL == previousMode) || (!HANDLE_DISPATCH_ON_BASE_INVOCATION_ONLY && 0 == _CFGetTSD(__CFTSDKeyIsInGCDMainQ)));
|
||||
if (libdispatchQSafe && (CFRunLoopGetMain() == rl) && CFSetContainsValue(rl->_commonModes, rlm->_name)) dispatchPort = _dispatch_get_main_queue_port_4CF();
|
||||
|
||||
|
||||
#if USE_DISPATCH_SOURCE_FOR_TIMERS
|
||||
mach_port_name_t modeQueuePort = MACH_PORT_NULL;
|
||||
if (rlm->_queue) {
|
||||
modeQueuePort = _dispatch_runloop_root_queue_get_port_4CF(rlm->_queue);
|
||||
if (!modeQueuePort) {
|
||||
CRASH("Unable to get port for run loop mode queue (%d)", -1);
|
||||
}
|
||||
}
|
||||
#endif
|
||||
|
||||
|
||||
dispatch_source_t timeout_timer = NULL;
|
||||
struct __timeout_context *timeout_context = (struct __timeout_context *)malloc(sizeof(*timeout_context));
|
||||
if (seconds <= 0.0) { // instant timeout
|
||||
seconds = 0.0;
|
||||
timeout_context->termTSR = 0ULL;
|
||||
} else if (seconds <= TIMER_INTERVAL_LIMIT) {
|
||||
dispatch_queue_t queue = pthread_main_np() ? __CFDispatchQueueGetGenericMatchingMain() : __CFDispatchQueueGetGenericBackground();
|
||||
timeout_timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
|
||||
dispatch_retain(timeout_timer);
|
||||
timeout_context->ds = timeout_timer;
|
||||
timeout_context->rl = (CFRunLoopRef)CFRetain(rl);
|
||||
timeout_context->termTSR = startTSR + __CFTimeIntervalToTSR(seconds);
|
||||
dispatch_set_context(timeout_timer, timeout_context); // source gets ownership of context
|
||||
dispatch_source_set_event_handler_f(timeout_timer, __CFRunLoopTimeout);
|
||||
dispatch_source_set_cancel_handler_f(timeout_timer, __CFRunLoopTimeoutCancel);
|
||||
uint64_t ns_at = (uint64_t)((__CFTSRToTimeInterval(startTSR) + seconds) * 1000000000ULL);
|
||||
dispatch_source_set_timer(timeout_timer, dispatch_time(1, ns_at), DISPATCH_TIME_FOREVER, 1000ULL);
|
||||
dispatch_resume(timeout_timer);
|
||||
} else {
|
||||
// 设置RunLoop超时时间
|
||||
seconds = 9999999999.0;
|
||||
timeout_context->termTSR = UINT64_MAX;
|
||||
}
|
||||
|
||||
|
||||
Boolean didDispatchPortLastTime = true;
|
||||
int32_t retVal = 0;
|
||||
do {
|
||||
#if DEPLOYMENT_TARGET_MACOSX || DEPLOYMENT_TARGET_EMBEDDED || DEPLOYMENT_TARGET_EMBEDDED_MINI
|
||||
voucher_mach_msg_state_t voucherState = VOUCHER_MACH_MSG_STATE_UNCHANGED;
|
||||
voucher_t voucherCopy = NULL;
|
||||
#endif
|
||||
uint8_t msg_buffer[3 * 1024];
|
||||
#if DEPLOYMENT_TARGET_MACOSX || DEPLOYMENT_TARGET_EMBEDDED || DEPLOYMENT_TARGET_EMBEDDED_MINI
|
||||
mach_msg_header_t *msg = NULL;
|
||||
mach_port_t livePort = MACH_PORT_NULL;
|
||||
#elif DEPLOYMENT_TARGET_WINDOWS
|
||||
HANDLE livePort = NULL;
|
||||
Boolean windowsMessageReceived = false;
|
||||
#endif
|
||||
__CFPortSet waitSet = rlm->_portSet;
|
||||
|
||||
|
||||
__CFRunLoopUnsetIgnoreWakeUps(rl);
|
||||
|
||||
|
||||
if (rlm->_observerMask & kCFRunLoopBeforeTimers)
|
||||
// 2. 通知 Observers: RunLoop 即将触发 Timer 回调
|
||||
__CFRunLoopDoObservers(rl, rlm, kCFRunLoopBeforeTimers);
|
||||
if (rlm->_observerMask & kCFRunLoopBeforeSources)
|
||||
// 3. 通知 Observers: RunLoop 即将触发 Source 回调
|
||||
__CFRunLoopDoObservers(rl, rlm, kCFRunLoopBeforeSources);
|
||||
// 执行被加入的block
|
||||
__CFRunLoopDoBlocks(rl, rlm);
|
||||
|
||||
|
||||
// 4. RunLoop 触发 Source0 (非port) 回调
|
||||
Boolean sourceHandledThisLoop = __CFRunLoopDoSources0(rl, rlm, stopAfterHandle);
|
||||
if (sourceHandledThisLoop) {
|
||||
// 执行被加入的block
|
||||
__CFRunLoopDoBlocks(rl, rlm);
|
||||
}
|
||||
|
||||
|
||||
Boolean poll = sourceHandledThisLoop || (0ULL == timeout_context->termTSR);
|
||||
|
||||
|
||||
// 5. 如果有 Source1 (基于port) 处于 ready 状态，直接处理这个 Source1 然后跳转去处理消息
|
||||
if (MACH_PORT_NULL != dispatchPort && !didDispatchPortLastTime) {
|
||||
#if DEPLOYMENT_TARGET_MACOSX || DEPLOYMENT_TARGET_EMBEDDED || DEPLOYMENT_TARGET_EMBEDDED_MINI
|
||||
msg = (mach_msg_header_t *)msg_buffer;
|
||||
|
||||
|
||||
if (__CFRunLoopServiceMachPort(dispatchPort, &msg, sizeof(msg_buffer), &livePort, 0, &voucherState, NULL)) {
|
||||
goto handle_msg;
|
||||
}
|
||||
#elif DEPLOYMENT_TARGET_WINDOWS
|
||||
if (__CFRunLoopWaitForMultipleObjects(NULL, &dispatchPort, 0, 0, &livePort, NULL)) {
|
||||
goto handle_msg;
|
||||
}
|
||||
#endif
|
||||
}
|
||||
|
||||
|
||||
didDispatchPortLastTime = false;
|
||||
|
||||
|
||||
// 通知 Observers: RunLoop 的线程即将进入休眠(sleep)
|
||||
if (!poll && (rlm->_observerMask & kCFRunLoopBeforeWaiting)) __CFRunLoopDoObservers(rl, rlm, kCFRunLoopBeforeWaiting);
|
||||
__CFRunLoopSetSleeping(rl);
|
||||
// do not do any user callouts after this point (after notifying of sleeping)
|
||||
|
||||
|
||||
// Must push the local-to-this-activation ports in on every loop
|
||||
// iteration, as this mode could be run re-entrantly and we don't
|
||||
// want these ports to get serviced.
|
||||
|
||||
|
||||
__CFPortSetInsert(dispatchPort, waitSet);
|
||||
|
||||
|
||||
__CFRunLoopModeUnlock(rlm);
|
||||
__CFRunLoopUnlock(rl);
|
||||
|
||||
|
||||
CFAbsoluteTime sleepStart = poll ? 0.0 : CFAbsoluteTimeGetCurrent();
|
||||
|
||||
|
||||
#if DEPLOYMENT_TARGET_MACOSX || DEPLOYMENT_TARGET_EMBEDDED || DEPLOYMENT_TARGET_EMBEDDED_MINI
|
||||
#if USE_DISPATCH_SOURCE_FOR_TIMERS
|
||||
do {
|
||||
if (kCFUseCollectableAllocator) {
|
||||
// objc_clear_stack(0);
|
||||
// <rdar://problem/16393959>
|
||||
memset(msg_buffer, 0, sizeof(msg_buffer));
|
||||
}
|
||||
msg = (mach_msg_header_t *)msg_buffer;
|
||||
|
||||
|
||||
__CFRunLoopServiceMachPort(waitSet, &msg, sizeof(msg_buffer), &livePort, poll ? 0 : TIMEOUT_INFINITY, &voucherState, &voucherCopy);
|
||||
|
||||
|
||||
if (modeQueuePort != MACH_PORT_NULL && livePort == modeQueuePort) {
|
||||
// Drain the internal queue. If one of the callout blocks sets the timerFired flag, break out and service the timer.
|
||||
while (_dispatch_runloop_root_queue_perform_4CF(rlm->_queue));
|
||||
if (rlm->_timerFired) {
|
||||
// Leave livePort as the queue port, and service timers below
|
||||
rlm->_timerFired = false;
|
||||
break;
|
||||
} else {
|
||||
if (msg && msg != (mach_msg_header_t *)msg_buffer) free(msg);
|
||||
}
|
||||
} else {
|
||||
// Go ahead and leave the inner loop.
|
||||
break;
|
||||
}
|
||||
} while (1);
|
||||
#else
|
||||
if (kCFUseCollectableAllocator) {
|
||||
// objc_clear_stack(0);
|
||||
// <rdar://problem/16393959>
|
||||
memset(msg_buffer, 0, sizeof(msg_buffer));
|
||||
}
|
||||
msg = (mach_msg_header_t *)msg_buffer;
|
||||
__CFRunLoopServiceMachPort(waitSet, &msg, sizeof(msg_buffer), &livePort, poll ? 0 : TIMEOUT_INFINITY, &voucherState, &voucherCopy);
|
||||
#endif
|
||||
|
||||
|
||||
|
||||
|
||||
#elif DEPLOYMENT_TARGET_WINDOWS
|
||||
// Here, use the app-supplied message queue mask. They will set this if they are interested in having this run loop receive windows messages.
|
||||
__CFRunLoopWaitForMultipleObjects(waitSet, NULL, poll ? 0 : TIMEOUT_INFINITY, rlm->_msgQMask, &livePort, &windowsMessageReceived);
|
||||
#endif
|
||||
|
||||
|
||||
__CFRunLoopLock(rl);
|
||||
__CFRunLoopModeLock(rlm);
|
||||
|
||||
|
||||
rl->_sleepTime += (poll ? 0.0 : (CFAbsoluteTimeGetCurrent() - sleepStart));
|
||||
|
||||
|
||||
// Must remove the local-to-this-activation ports in on every loop
|
||||
// iteration, as this mode could be run re-entrantly and we don't
|
||||
// want these ports to get serviced. Also, we don't want them left
|
||||
// in there if this function returns.
|
||||
|
||||
|
||||
__CFPortSetRemove(dispatchPort, waitSet);
|
||||
|
||||
|
||||
__CFRunLoopSetIgnoreWakeUps(rl);
|
||||
|
||||
|
||||
// user callouts now OK again
|
||||
__CFRunLoopUnsetSleeping(rl);
|
||||
|
||||
|
||||
// 8. 通知 Observers: RunLoop 的线程刚刚被唤醒了
|
||||
if (!poll && (rlm->_observerMask & kCFRunLoopAfterWaiting)) __CFRunLoopDoObservers(rl, rlm, kCFRunLoopAfterWaiting);
|
||||
// 处理消息
|
||||
handle_msg:;
|
||||
__CFRunLoopSetIgnoreWakeUps(rl);
|
||||
|
||||
|
||||
#if DEPLOYMENT_TARGET_WINDOWS
|
||||
if (windowsMessageReceived) {
|
||||
// These Win32 APIs cause a callout, so make sure we're unlocked first and relocked after
|
||||
__CFRunLoopModeUnlock(rlm);
|
||||
__CFRunLoopUnlock(rl);
|
||||
|
||||
|
||||
if (rlm->_msgPump) {
|
||||
rlm->_msgPump();
|
||||
} else {
|
||||
MSG msg;
|
||||
if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE | PM_NOYIELD)) {
|
||||
TranslateMessage(&msg);
|
||||
DispatchMessage(&msg);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
__CFRunLoopLock(rl);
|
||||
__CFRunLoopModeLock(rlm);
|
||||
sourceHandledThisLoop = true;
|
||||
|
||||
|
||||
// To prevent starvation of sources other than the message queue, we check again to see if any other sources need to be serviced
|
||||
// Use 0 for the mask so windows messages are ignored this time. Also use 0 for the timeout, because we're just checking to see if the things are signalled right now -- we will wait on them again later.
|
||||
// NOTE: Ignore the dispatch source (it's not in the wait set anymore) and also don't run the observers here since we are polling.
|
||||
__CFRunLoopSetSleeping(rl);
|
||||
__CFRunLoopModeUnlock(rlm);
|
||||
__CFRunLoopUnlock(rl);
|
||||
|
||||
|
||||
__CFRunLoopWaitForMultipleObjects(waitSet, NULL, 0, 0, &livePort, NULL);
|
||||
|
||||
|
||||
__CFRunLoopLock(rl);
|
||||
__CFRunLoopModeLock(rlm);
|
||||
__CFRunLoopUnsetSleeping(rl);
|
||||
// If we have a new live port then it will be handled below as normal
|
||||
}
|
||||
|
||||
|
||||
|
||||
|
||||
#endif
|
||||
if (MACH_PORT_NULL == livePort) {
|
||||
CFRUNLOOP_WAKEUP_FOR_NOTHING();
|
||||
// handle nothing
|
||||
} else if (livePort == rl->_wakeUpPort) {
|
||||
CFRUNLOOP_WAKEUP_FOR_WAKEUP();
|
||||
// do nothing on Mac OS
|
||||
#if DEPLOYMENT_TARGET_WINDOWS
|
||||
// Always reset the wake up port, or risk spinning forever
|
||||
ResetEvent(rl->_wakeUpPort);
|
||||
#endif
|
||||
}
|
||||
#if USE_DISPATCH_SOURCE_FOR_TIMERS
|
||||
else if (modeQueuePort != MACH_PORT_NULL && livePort == modeQueuePort) {
|
||||
CFRUNLOOP_WAKEUP_FOR_TIMER();
|
||||
|
||||
|
||||
if (!__CFRunLoopDoTimers(rl, rlm, mach_absolute_time())) {
|
||||
// Re-arm the next timer, because we apparently fired early
|
||||
__CFArmNextTimerInMode(rlm, rl);
|
||||
}
|
||||
}
|
||||
#endif
|
||||
#if USE_MK_TIMER_TOO
|
||||
// 9.1 如果一个 Timer 到时间了，触发这个Timer的回调
|
||||
else if (rlm->_timerPort != MACH_PORT_NULL && livePort == rlm->_timerPort) {
|
||||
CFRUNLOOP_WAKEUP_FOR_TIMER();
|
||||
// On Windows, we have observed an issue where the timer port is set before the time which we requested it to be set. For example, we set the fire time to be TSR 167646765860, but it is actually observed firing at TSR 167646764145, which is 1715 ticks early. The result is that, when __CFRunLoopDoTimers checks to see if any of the run loop timers should be firing, it appears to be 'too early' for the next timer, and no timers are handled.
|
||||
// In this case, the timer port has been automatically reset (since it was returned from MsgWaitForMultipleObjectsEx), and if we do not re-arm it, then no timers will ever be serviced again unless something adjusts the timer list (e.g. adding or removing timers). The fix for the issue is to reset the timer here if CFRunLoopDoTimers did not handle a timer itself. 9308754
|
||||
if (!__CFRunLoopDoTimers(rl, rlm, mach_absolute_time())) {
|
||||
// Re-arm the next timer
|
||||
__CFArmNextTimerInMode(rlm, rl);
|
||||
}
|
||||
}
|
||||
#endif
|
||||
// 9.2 如果有dispatch到main_queue的block，执行block
|
||||
else if (livePort == dispatchPort) {
|
||||
CFRUNLOOP_WAKEUP_FOR_DISPATCH();
|
||||
__CFRunLoopModeUnlock(rlm);
|
||||
__CFRunLoopUnlock(rl);
|
||||
_CFSetTSD(__CFTSDKeyIsInGCDMainQ, (void *)6, NULL);
|
||||
#if DEPLOYMENT_TARGET_WINDOWS
|
||||
void *msg = 0;
|
||||
#endif
|
||||
/**/
|
||||
__CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__(msg);
|
||||
_CFSetTSD(__CFTSDKeyIsInGCDMainQ, (void *)0, NULL);
|
||||
__CFRunLoopLock(rl);
|
||||
__CFRunLoopModeLock(rlm);
|
||||
sourceHandledThisLoop = true;
|
||||
didDispatchPortLastTime = true;
|
||||
}
|
||||
// 9.3 如果一个 Source1 (基于port) 发出事件了，处理这个事件
|
||||
else {
|
||||
CFRUNLOOP_WAKEUP_FOR_SOURCE();
|
||||
|
||||
|
||||
// If we received a voucher from this mach_msg, then put a copy of the new voucher into TSD. CFMachPortBoost will look in the TSD for the voucher. By using the value in the TSD we tie the CFMachPortBoost to this received mach_msg explicitly without a chance for anything in between the two pieces of code to set the voucher again.
|
||||
voucher_t previousVoucher = _CFSetTSD(__CFTSDKeyMachMessageHasVoucher, (void *)voucherCopy, os_release);
|
||||
|
||||
|
||||
/**/
|
||||
CFRunLoopSourceRef rls = __CFRunLoopModeFindSourceForMachPort(rl, rlm, livePort);
|
||||
if (rls) {
|
||||
#if DEPLOYMENT_TARGET_MACOSX || DEPLOYMENT_TARGET_EMBEDDED || DEPLOYMENT_TARGET_EMBEDDED_MINI
|
||||
mach_msg_header_t *reply = NULL;
|
||||
sourceHandledThisLoop = __CFRunLoopDoSource1(rl, rlm, rls, msg, msg->msgh_size, &reply) || sourceHandledThisLoop;
|
||||
if (NULL != reply) {
|
||||
(void)mach_msg(reply, MACH_SEND_MSG, reply->msgh_size, 0, MACH_PORT_NULL, 0, MACH_PORT_NULL);
|
||||
CFAllocatorDeallocate(kCFAllocatorSystemDefault, reply);
|
||||
}
|
||||
#elif DEPLOYMENT_TARGET_WINDOWS
|
||||
sourceHandledThisLoop = __CFRunLoopDoSource1(rl, rlm, rls) || sourceHandledThisLoop;
|
||||
#endif
|
||||
}
|
||||
|
||||
|
||||
// Restore the previous voucher
|
||||
_CFSetTSD(__CFTSDKeyMachMessageHasVoucher, previousVoucher, os_release);
|
||||
|
||||
|
||||
}
|
||||
#if DEPLOYMENT_TARGET_MACOSX || DEPLOYMENT_TARGET_EMBEDDED || DEPLOYMENT_TARGET_EMBEDDED_MINI
|
||||
if (msg && msg != (mach_msg_header_t *)msg_buffer) free(msg);
|
||||
#endif
|
||||
// 执行加入到Loop的block
|
||||
__CFRunLoopDoBlocks(rl, rlm);
|
||||
|
||||
if (sourceHandledThisLoop && stopAfterHandle) {
|
||||
// 进入loop时参数说处理完事件就返回
|
||||
retVal = kCFRunLoopRunHandledSource;
|
||||
} else if (timeout_context->termTSR < mach_absolute_time()) {
|
||||
// 超出传入参数标记的超时时间了
|
||||
retVal = kCFRunLoopRunTimedOut;
|
||||
} else if (__CFRunLoopIsStopped(rl)) {
|
||||
__CFRunLoopUnsetStopped(rl);
|
||||
// 被外部调用者强制停止了
|
||||
retVal = kCFRunLoopRunStopped;
|
||||
} else if (rlm->_stopped) {
|
||||
rlm->_stopped = false;
|
||||
retVal = kCFRunLoopRunStopped;
|
||||
} else if (__CFRunLoopModeIsEmpty(rl, rlm, previousMode)) {
|
||||
// source/timer一个都没有
|
||||
retVal = kCFRunLoopRunFinished;
|
||||
}
|
||||
|
||||
|
||||
#if DEPLOYMENT_TARGET_MACOSX || DEPLOYMENT_TARGET_EMBEDDED || DEPLOYMENT_TARGET_EMBEDDED_MINI
|
||||
voucher_mach_msg_revert(voucherState);
|
||||
os_release(voucherCopy);
|
||||
#endif
|
||||
// 如果没超时，mode里没空，loop也没被停止，那继续loop
|
||||
} while (0 == retVal);
|
||||
|
||||
|
||||
if (timeout_timer) {
|
||||
dispatch_source_cancel(timeout_timer);
|
||||
dispatch_release(timeout_timer);
|
||||
} else {
|
||||
free(timeout_context);
|
||||
}
|
||||
return retVal;
|
||||
}
|
||||
```
|
||||
|
||||
Reference in New Issue
Block a user