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CFRunLoop

作者：很楠不爱3 | 2024-03-20 14:13:59

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cfsetcontainsvalue

数据结构

__CFRunLoopMode

  1.  struct __CFRunLoopMode {
  2.     CFRuntimeBase _base;
  3.     pthread_mutex_t _lock;  /* must have the run loop locked before locking 
  4.     this */
  5. //mode名
  6.     CFStringRef _name;
  7.     Boolean _stopped;
  8.     char _padding[3];
  9. //source0 源
  10.     CFMutableSetRef _sources0;
  11. //source1 源
  12.     CFMutableSetRef _sources1;
  13. //observer 源
  14.     CFMutableArrayRef _observers;
  15. //timer 源
  16.     CFMutableArrayRef _timers;
  17.  
  18. //mach port 到 mode的映射,为了在runloop主逻辑中过滤runloop自己的port消息。
  19.     CFMutableDictionaryRef _portToV1SourceMap;
  20.  
  21. //记录了所有当前mode中需要监听的port，作为调用监听消息函数的参数。
  22.     __CFPortSet _portSet;
  23.     CFIndex _observerMask;
  24. #if USE_DISPATCH_SOURCE_FOR_TIMERS
  25.     dispatch_source_t _timerSource;
  26.     dispatch_queue_t _queue;
  27.     Boolean _timerFired; // set to true by the source when a timer has fired
  28.     Boolean _dispatchTimerArmed;
  29. #endif
  30. #if USE_MK_TIMER_TOO
  31. //使用 mk timer， 用到的mach port，和source1类似，都依赖于mach port
  32.     mach_port_t _timerPort;
  33.     Boolean _mkTimerArmed;
  34. #endif
  35. //timer触发的理想时间
  36.     uint64_t _timerSoftDeadline; /* TSR */
  37. //timer触发的实际时间，理想时间加上tolerance（偏差）
  38.     uint64_t _timerHardDeadline; /* TSR */
  39. };
  40. 复制代码

__CFRunLoop

  1. struct __CFRunLoop {
  2.     CFRuntimeBase _base;
  3.     pthread_mutex_t _lock;          /* locked for accessing mode list */
  4.  
  5. //用于手动将当前runloop线程唤醒，通过调用CFRunLoopWakeUp完成，
  6. //CFRunLoopWakeUp会向_wakeUpPort发送一条消息
  7.     __CFPort _wakeUpPort;           // used for CFRunLoopWakeUp 
  8.     Boolean _unused;
  9.     volatile _per_run_data *_perRunData; // reset for runs of the run loop
  10.     pthread_t _pthread;
  11.     uint32_t _winthread;
  12. //记录了当前runloop中所有的mode名
  13.     CFMutableSetRef _commonModes;
  14. //记录了当前runloop中所有注册到commonMode中的源
  15.     CFMutableSetRef _commonModeItems;
  16.     CFRunLoopModeRef _currentMode;
  17.     CFMutableSetRef _modes;
  18. //记录了添加到runloop中的block，它也可以像其他源一样被runloop处理，
  19. //通过CFRunLoopPerformBlock可向runloop中添加block任务。
  20.     struct _block_item *_blocks_head;
  21.     struct _block_item *_blocks_tail;
  22.     CFTypeRef _counterpart;
  23. };
  24. 复制代码

__CFRunLoops

  1. //全局字典，保存线程和对应runloop之间的关系
  2. static CFMutableDictionaryRef __CFRunLoops = NULL;
  3. 复制代码

函数：

__CFRunLoopRun

  1. static int32_t __CFRunLoopRun(CFRunLoopRef rl, CFRunLoopModeRef rlm, 
  2.     CFTimeInterval seconds, Boolean stopAfterHandle, CFRunLoopModeRef 
  3.     previousMode) {
  4.     //获取系统启动之后cpu嘀嗒数
  5.     uint64_t startTSR = mach_absolute_time();
  6.     if (__CFRunLoopIsStopped(rl)) {
  7.         __CFRunLoopUnsetStopped(rl);
  8.     return kCFRunLoopRunStopped;
  9.     } else if (rlm->_stopped) {
  10.     rlm->_stopped = false;
  11.     return kCFRunLoopRunStopped;
  12.     }
  13.      
  14.     //mach 端口, 线程之间通信的对象
  15.     mach_port_name_t dispatchPort = MACH_PORT_NULL;
  16.     //这里主要是为了判断当前线程是否为主线程        
  17.     Boolean libdispatchQSafe = pthread_main_np() && ((
  18.         HANDLE_DISPATCH_ON_BASE_INVOCATION_ONLY && NULL == previousMode) || (!
  19.         HANDLE_DISPATCH_ON_BASE_INVOCATION_ONLY && 0 == _CFGetTSD(
  20.             __CFTSDKeyIsInGCDMainQ)));
  21.     if (libdispatchQSafe && (CFRunLoopGetMain() == rl) && CFSetContainsValue(rl
  22.         ->_commonModes, rlm->_name)) dispatchPort = 
  23.         _dispatch_get_main_queue_port_4CF();
  24.      
  25.     //使用GCD实现runloop超时功能
  26.     dispatch_source_t timeout_timer = NULL;
  27.     struct __timeout_context *timeout_context = (struct __timeout_context *)
  28.     malloc(sizeof(*timeout_context));
  29.     //seconds是设置的runloop超时时间
  30.     if (seconds <= 0.0) { // instant timeout
  31.         seconds = 0.0;
  32.         timeout_context->termTSR = 0ULL;
  33.     } else if (seconds <= TIMER_INTERVAL_LIMIT) {
  34.     dispatch_queue_t queue = dispatch_get_global_queue(
  35.         DISPATCH_QUEUE_PRIORITY_HIGH, DISPATCH_QUEUE_OVERCOMMIT);
  36.     timeout_timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, 
  37.         queue);
  38.         dispatch_retain(timeout_timer);
  39.     timeout_context->ds = timeout_timer;
  40.     timeout_context->rl = (CFRunLoopRef)CFRetain(rl);
  41.     timeout_context->termTSR = startTSR + __CFTimeIntervalToTSR(seconds);
  42.     dispatch_set_context(timeout_timer, timeout_context); // source gets 
  43.     //ownership of context
  44.     dispatch_source_set_event_handler_f(timeout_timer, __CFRunLoopTimeout);
  45.         dispatch_source_set_cancel_handler_f(timeout_timer, 
  46.             __CFRunLoopTimeoutCancel);
  47.         uint64_t ns_at = (uint64_t)((__CFTSRToTimeInterval(startTSR) + seconds)
  48.          * 1000000000ULL);
  49.         dispatch_source_set_timer(timeout_timer, dispatch_time(1, ns_at), 
  50.         DISPATCH_TIME_FOREVER, 1000ULL);
  51.         dispatch_resume(timeout_timer);
  52.     } else { // infinite timeout
  53.         seconds = 9999999999.0;
  54.         timeout_context->termTSR = UINT64_MAX;
  55.     }
  56.     Boolean didDispatchPortLastTime = true;
  57.     int32_t retVal = 0;
  58.     do {
  59.         uint8_t msg_buffer[3 * 1024];
  60.         mach_msg_header_t *msg = NULL;
  61.         mach_port_t livePort = MACH_PORT_NULL;
  62.     __CFPortSet waitSet = rlm->_portSet;
  63.         __CFRunLoopUnsetIgnoreWakeUps(rl);
  64.         //rl->_perRunData->ignoreWakeUps = 0x0;
  65.         if (rlm->_observerMask & kCFRunLoopBeforeTimers) __CFRunLoopDoObservers
  66.         (rl, rlm, kCFRunLoopBeforeTimers);
  67.         if (rlm->_observerMask & kCFRunLoopBeforeSources) 
  68.         __CFRunLoopDoObservers(rl, rlm, kCFRunLoopBeforeSources);
  69. //Perform blocks queued by CFRunLoopPerformBlock;
  70.     __CFRunLoopDoBlocks(rl, rlm);
  71.         Boolean sourceHandledThisLoop = __CFRunLoopDoSources0(rl, rlm, 
  72.             stopAfterHandle);
  73.         //如果rl中有source0消息
  74.         if (sourceHandledThisLoop) {
  75.             //处理block  Perform blocks newly queued by CFRunLoopPerformBlock;
  76.             __CFRunLoopDoBlocks(rl, rlm);
  77.        }
  78. //poll标志着有没有处理source0的消息，如果没有则为false，反之为true
  79.         Boolean poll = sourceHandledThisLoop || (0ULL == timeout_context->
  80.             termTSR);
  81.         //第一次进来不走这个逻辑，didDispatchPortLastTime是true
  82.         if (MACH_PORT_NULL != dispatchPort && !didDispatchPortLastTime) {
  83.             msg = (mach_msg_header_t *)msg_buffer;
  84.             //__CFRunLoopServiceMachPort用于接受指定端口(一个也可以是多个)
  85.             //的消息,最后一个参数代表当端口无消息的时候是否休眠,0是立刻返回不休眠,
  86.             //TIMEOUT_INFINITY代表休眠
  87.             //处理通过GCD派发到主线程的任务,这些任务优先级最高会被最先处理
  88.             if (__CFRunLoopServiceMachPort(dispatchPort, &msg, sizeof(
  89.                 msg_buffer), &livePort, 0)) {
  90.                 goto handle_msg;
  91.             }
  92.         }
  93.         didDispatchPortLastTime = false;
  94. //根据之前有没有处理过source0消息，来判断如果也没有source1消息的时候是否让线程进入睡眠，这里处
  95. //理observer源，如果睡眠则通知Observer进入睡眠。
  96.     if (!poll && (rlm->_observerMask & kCFRunLoopBeforeWaiting)) 
  97.     __CFRunLoopDoObservers(rl, rlm, kCFRunLoopBeforeWaiting);
  98.     __CFRunLoopSetSleeping(rl);
  99.     // do not do any user callouts after this point (after notifying of 
  100.         //sleeping)
  101.         // Must push the local-to-this-activation ports in on every loop
  102.         // iteration, as this mode could be run re-entrantly and we don't
  103.         // want these ports to get serviced.
  104.         __CFPortSetInsert(dispatchPort, waitSet);
  105.          
  106.     __CFRunLoopModeUnlock(rlm);
  107.     __CFRunLoopUnlock(rl);
  108.     if (kCFUseCollectableAllocator) {
  109.         objc_clear_stack(0);
  110.         memset(msg_buffer, 0, sizeof(msg_buffer));
  111.     }
  112.     msg = (mach_msg_header_t *)msg_buffer;
  113.     //如果poll为null，且waitset中无port有消息,线程进入休眠
  114.     __CFRunLoopServiceMachPort(waitSet, &msg, sizeof(msg_buffer), &livePort, 
  115.     poll ? 0 : TIMEOUT_INFINITY);
  116.      
  117.     __CFRunLoopLock(rl);
  118.     __CFRunLoopModeLock(rlm);
  119.     // Must remove the local-to-this-activation ports in on every loop
  120.     // iteration, as this mode could be run re-entrantly and we don't
  121.     // want these ports to get serviced. Also, we don't want them left
  122.     // in there if this function returns.
  123.     __CFPortSetRemove(dispatchPort, waitSet);
  124.      
  125.     __CFRunLoopSetIgnoreWakeUps(rl);
  126.         // user callouts now OK again
  127.     __CFRunLoopUnsetSleeping(rl);
  128.     //处理observer源，线程醒来
  129.     if (!poll && (rlm->_observerMask & kCFRunLoopAfterWaiting)) 
  130.     __CFRunLoopDoObservers(rl, rlm, kCFRunLoopAfterWaiting);
  131.         handle_msg:;
  132.         __CFRunLoopSetIgnoreWakeUps(rl);
  133.         if (MACH_PORT_NULL == livePort) {
  134.             CFRUNLOOP_WAKEUP_FOR_NOTHING();
  135.             // handle nothing
  136. //通过CFRunloopWake将当前线程唤醒
  137.         } else if (livePort == rl->_wakeUpPort) {
  138.             CFRUNLOOP_WAKEUP_FOR_WAKEUP();
  139.             // do nothing on Mac OS
  140.         }
  141. //处理timer源
  142.         else if (rlm->_timerPort != MACH_PORT_NULL && livePort == rlm->
  143.             _timerPort) {
  144.             CFRUNLOOP_WAKEUP_FOR_TIMER();
  145.             if (!__CFRunLoopDoTimers(rl, rlm, mach_absolute_time())) {
  146.                 // Re-arm the next timer
  147.                 __CFArmNextTimerInMode(rlm, rl);
  148.             }
  149.         }
  150. //通过GCD派发给主线程的任务
  151.         else if (livePort == dispatchPort) {
  152.             CFRUNLOOP_WAKEUP_FOR_DISPATCH();
  153.             __CFRunLoopModeUnlock(rlm);
  154.             __CFRunLoopUnlock(rl);
  155.             _CFSetTSD(__CFTSDKeyIsInGCDMainQ, (void *)6, NULL);
  156.             __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__(msg);
  157.             _CFSetTSD(__CFTSDKeyIsInGCDMainQ, (void *)0, NULL);
  158.             __CFRunLoopLock(rl);
  159.             __CFRunLoopModeLock(rlm);
  160.             sourceHandledThisLoop = true;
  161.             didDispatchPortLastTime = true;
  162.         } else {
  163. //通过macPort给当前线程派发消息,处理source1
  164.             CFRUNLOOP_WAKEUP_FOR_SOURCE();
  165.             // Despite the name, this works for windows handles as well
  166.             //过滤macPort消息，有一些消息不一定是runloop中注册的，这里只处理runloop中注册的
  167.             //消息，在rlm->_portToV1SourceMap通过macPort找有没有对应的runloopMode
  168.             CFRunLoopSourceRef rls = __CFRunLoopModeFindSourceForMachPort(rl, 
  169.                 rlm, livePort);
  170.             if (rls) {
  171.                 mach_msg_header_t *reply = NULL;
  172.                 sourceHandledThisLoop = __CFRunLoopDoSource1(rl, rlm, rls, msg,
  173.                  msg->msgh_size, &reply) || sourceHandledThisLoop;
  174.                 if (NULL != reply) {
  175.                     //当前线程处理完source1，给发消息的线程反馈消息, 
  176.                     //MACH_SEND_MSG表示给replay端口发送消息
  177.                     (void)mach_msg(reply, MACH_SEND_MSG, reply->msgh_size, 0, 
  178.                         MACH_PORT_NULL, 0, MACH_PORT_NULL);
  179.                     CFAllocatorDeallocate(kCFAllocatorSystemDefault, reply);
  180.                 }
  181.            }
  182.         }
  183.     if (msg && msg != (mach_msg_header_t *)msg_buffer) free(msg);
  184.          
  185.     __CFRunLoopDoBlocks(rl, rlm);
  186.     if (sourceHandledThisLoop && stopAfterHandle) {
  187.         retVal = kCFRunLoopRunHandledSource;
  188.     } else if (timeout_context->termTSR < mach_absolute_time()) {
  189.         //runloop超时时间到
  190.             retVal = kCFRunLoopRunTimedOut;
  191.     } else if (__CFRunLoopIsStopped(rl)) {
  192.             __CFRunLoopUnsetStopped(rl);
  193.         retVal = kCFRunLoopRunStopped;
  194.     } else if (rlm->_stopped) {
  195.         rlm->_stopped = false;
  196.         retVal = kCFRunLoopRunStopped;
  197.     } else if (__CFRunLoopModeIsEmpty(rl, rlm, previousMode)) {
  198.         retVal = kCFRunLoopRunFinished;
  199.     }
  200.     } while (0 == retVal);
  201.     if (timeout_timer) {
  202.         dispatch_source_cancel(timeout_timer);
  203.         dispatch_release(timeout_timer);
  204.     } else {
  205.         free(timeout_context);
  206.     }
  207.     return retVal;
  208. }
  209. 复制代码

CFRunLoopAddSource

  1. void CFRunLoopAddSource(CFRunLoopRef rl, CFRunLoopSourceRef rls, 
  2.     CFStringRef modeName) {    /* DOES CALLOUT */
  3.     CHECK_FOR_FORK();
  4.     if (__CFRunLoopIsDeallocating(rl)) return;
  5.     if (!__CFIsValid(rls)) return;
  6.     Boolean doVer0Callout = false;
  7.     __CFRunLoopLock(rl);
  8.     if (modeName == kCFRunLoopCommonModes) {
  9.         //par1 : 处理commonModeItmes的逻辑
  10. /*rl->_commonModes的作用是记录了当前runloop中标记为commonMode的mode，rl->_commonModeI
  11. tems记录了当前runloop中注册到commonMode中的源
  12. 两者用来处理跟commonMode相关的逻辑，比如当一个mode被标记为commonMode的时候，会将rl->_common
  13. ModeItems中的源添加到新的mode当中去，在当前mode下这些源的消息就会被
  14. 监听并处理。例如一个timer被注册到commonMode中，那么在所有被标记为commonMode的mode中都会处理该timer的消息。
  15. */
  16.     CFSetRef set = rl->_commonModes ? CFSetCreateCopy(kCFAllocatorSystemDefault
  17.         , rl->_commonModes) : NULL;
  18.     if (NULL == rl->_commonModeItems) {
  19.         rl->_commonModeItems = CFSetCreateMutable(kCFAllocatorSystemDefault, 0, &kCFTypeSetCallBacks);
  20.     }
  21.     CFSetAddValue(rl->_commonModeItems, rls);
  22.     if (NULL != set) {
  23.         CFTypeRef context[2] = {rl, rls};
  24.         /* add new item to all common-modes */
  25.         //对每一个mode，调用part2的逻辑
  26.         CFSetApplyFunction(set, (__CFRunLoopAddItemToCommonModes), (void *)context);
  27.         CFRelease(set);
  28.     }
  29.     } else {
  30.     //part2 : 处理某个具体的mode中addSource的逻辑
  31.     CFRunLoopModeRef rlm = __CFRunLoopFindMode(rl, modeName, true);
  32.     if (NULL != rlm && NULL == rlm->_sources0) {
  33.         rlm->_sources0 = CFSetCreateMutable(kCFAllocatorSystemDefault, 0, &
  34.             kCFTypeSetCallBacks);
  35.         rlm->_sources1 = CFSetCreateMutable(kCFAllocatorSystemDefault, 0, &
  36.             kCFTypeSetCallBacks);
  37.         rlm->_portToV1SourceMap = CFDictionaryCreateMutable(
  38.             kCFAllocatorSystemDefault, 0, NULL, NULL);
  39.     }
  40.     if (NULL != rlm && !CFSetContainsValue(rlm->_sources0, rls) && !
  41.     CFSetContainsValue(rlm->_sources1, rls)) {
  42.         if (0 == rls->_context.version0.version) {
  43.             CFSetAddValue(rlm->_sources0, rls);
  44.         } else if (1 == rls->_context.version0.version) {
  45.             CFSetAddValue(rlm->_sources1, rls);
  46.         __CFPort src_port = rls->_context.version1.getPort(rls->_context.
  47.             version1.info);
  48.         if (CFPORT_NULL != src_port) {
  49.         //rlm->_portToV1SourceMap是port到source1的映射，
  50.         //为了在runloop主逻辑中过滤runloop自己的port消息。
  51.             CFDictionarySetValue(rlm->_portToV1SourceMap, (const void *)(
  52.                 uintptr_t)src_port, rls);
  53.         //rml->_portSet记录了所有当前mode中需要监听的port，作为调用监听消息函数的参数。
  54.             __CFPortSetInsert(src_port, rlm->_portSet);
  55.             }
  56.         }
  57.         __CFRunLoopSourceLock(rls);
  58.         if (NULL == rls->_runLoops) {
  59.             rls->_runLoops = CFBagCreateMutable(kCFAllocatorSystemDefault, 0, &
  60.             kCFTypeBagCallBacks); // sources retain run loops!
  61.         }
  62.         CFBagAddValue(rls->_runLoops, rl);
  63.         __CFRunLoopSourceUnlock(rls);
  64.         if (0 == rls->_context.version0.version) {
  65.             if (NULL != rls->_context.version0.schedule) {
  66.                 doVer0Callout = true;
  67.             }
  68.         }
  69.     }
  70.         if (NULL != rlm) {
  71.         __CFRunLoopModeUnlock(rlm);
  72.     }
  73.     }
  74.     __CFRunLoopUnlock(rl);
  75.     if (doVer0Callout) {
  76.         // although it looses some protection for the source, we have no 
  77.         //choice but
  78.         // to do this after unlocking the run loop and mode locks, to avoid 
  79.         //deadlocks
  80.         // where the source wants to take a lock which is already held in 
  81.         //another
  82.         // thread which is itself waiting for a run loop/mode lock
  83.     rls->_context.version0.schedule(rls->_context.version0.info, rl, modeName);   /* CALLOUT */
  84.     }
  85. }
  86. 复制代码

CFRunLoopRemoveSource

  1. void CFRunLoopRemoveSource(CFRunLoopRef rl, CFRunLoopSourceRef rls, 
  2.     CFStringRef modeName) { /* DOES CALLOUT */
  3.     CHECK_FOR_FORK();
  4.     Boolean doVer0Callout = false, doRLSRelease = false;
  5.     __CFRunLoopLock(rl);
  6.     if (modeName == kCFRunLoopCommonModes) {
  7.         if (NULL != rl->_commonModeItems && CFSetContainsValue(rl->
  8.             _commonModeItems, rls)) {
  9.             CFSetRef set = rl->_commonModes ? CFSetCreateCopy(
  10.                 kCFAllocatorSystemDefault, rl->_commonModes) : NULL;
  11.             CFSetRemoveValue(rl->_commonModeItems, rls);
  12.             if (NULL != set) {
  13.             CFTypeRef context[2] = {rl, rls};
  14.             /* remove new item from all common-modes */
  15.             CFSetApplyFunction(set, (__CFRunLoopRemoveItemFromCommonModes), (
  16.                 void *)context);
  17.             CFRelease(set);
  18.             }
  19.         }
  20.     } else {
  21.     CFRunLoopModeRef rlm = __CFRunLoopFindMode(rl, modeName, false);
  22.     if (NULL != rlm && ((NULL != rlm->_sources0 && CFSetContainsValue(rlm->
  23.         _sources0, rls)) || (NULL != rlm->_sources1 && CFSetContainsValue(rlm->
  24.             _sources1, rls)))) {
  25.         //source0或者source1中的一种
  26.         CFRetain(rls);
  27.         if (1 == rls->_context.version0.version) {
  28.         __CFPort src_port = rls->_context.version1.getPort(rls->_context.
  29.             version1.info);
  30.                 if (CFPORT_NULL != src_port) {
  31.             CFDictionaryRemoveValue(rlm->_portToV1SourceMap, (const void *)(
  32.                 uintptr_t)src_port);
  33.                     __CFPortSetRemove(src_port, rlm->_portSet);
  34.                 }
  35.         }
  36.         CFSetRemoveValue(rlm->_sources0, rls);
  37.         CFSetRemoveValue(rlm->_sources1, rls);
  38.             __CFRunLoopSourceLock(rls);
  39.             if (NULL != rls->_runLoops) {
  40.                 CFBagRemoveValue(rls->_runLoops, rl);
  41.             }
  42.             __CFRunLoopSourceUnlock(rls);
  43.         if (0 == rls->_context.version0.version) {
  44.             if (NULL != rls->_context.version0.cancel) {
  45.                 doVer0Callout = true;
  46.             }
  47.         }
  48.         doRLSRelease = true;
  49.     }
  50.         if (NULL != rlm) {
  51.         __CFRunLoopModeUnlock(rlm);
  52.     }
  53.     }
  54.     __CFRunLoopUnlock(rl);
  55.     if (doVer0Callout) {
  56.         // although it looses some protection for the source, we have no choice but
  57.         // to do this after unlocking the run loop and mode locks, to avoid deadlocks
  58.         // where the source wants to take a lock which is already held in another
  59.         // thread which is itself waiting for a run loop/mode lock
  60.         rls->_context.version0.cancel(rls->_context.version0.info, rl, modeName); /* CALLOUT */
  61.     }
  62.     if (doRLSRelease) CFRelease(rls);
  63. }
  64. 复制代码

CFRunLoopAddTimer

  1. void CFRunLoopAddTimer(CFRunLoopRef rl, CFRunLoopTimerRef rlt, CFStringRef 
  2.     modeName) {   
  3.     CHECK_FOR_FORK();
  4.     if (__CFRunLoopIsDeallocating(rl)) return;
  5.     if (!__CFIsValid(rlt) || (NULL != rlt->_runLoop && rlt->_runLoop != rl)) 
  6.     return;
  7.     __CFRunLoopLock(rl);
  8.     if (modeName == kCFRunLoopCommonModes) {
  9.     CFSetRef set = rl->_commonModes ? CFSetCreateCopy(kCFAllocatorSystemDefault
  10.         , rl->_commonModes) : NULL;
  11.     if (NULL == rl->_commonModeItems) {
  12.         rl->_commonModeItems = CFSetCreateMutable(kCFAllocatorSystemDefault, 0,
  13.          &kCFTypeSetCallBacks);
  14.     }
  15.     CFSetAddValue(rl->_commonModeItems, rlt);
  16.     if (NULL != set) {
  17.         CFTypeRef context[2] = {rl, rlt};
  18.         /* add new item to all common-modes */
  19.         CFSetApplyFunction(set, (__CFRunLoopAddItemToCommonModes), (void *)
  20.         context);
  21.         CFRelease(set);
  22.     }
  23.     } else {
  24.     CFRunLoopModeRef rlm = __CFRunLoopFindMode(rl, modeName, true);
  25.     if (NULL != rlm) {
  26.             if (NULL == rlm->_timers) {
  27.                 CFArrayCallBacks cb = kCFTypeArrayCallBacks;
  28.                 cb.equal = NULL;
  29.                 rlm->_timers = CFArrayCreateMutable(kCFAllocatorSystemDefault, 
  30.                     0, &cb);
  31.             }
  32.     }
  33.     if (NULL != rlm && !CFSetContainsValue(rlt->_rlModes, rlm->_name)) {
  34.             __CFRunLoopTimerLock(rlt);
  35.             if (NULL == rlt->_runLoop) {
  36.         rlt->_runLoop = rl;
  37.         } else if (rl != rlt->_runLoop) {
  38.                 __CFRunLoopTimerUnlock(rlt);
  39.             __CFRunLoopModeUnlock(rlm);
  40.                 __CFRunLoopUnlock(rl);
  41.         return;
  42.         }
  43.         CFSetAddValue(rlt->_rlModes, rlm->_name);
  44.             __CFRunLoopTimerUnlock(rlt);
  45.             __CFRunLoopTimerFireTSRLock();
  46.             //__CFRepositionTimerInMode是添加或者删除timer,
  47.             //这里是往rlm->_timers添加timer
  48.             __CFRepositionTimerInMode(rlm, rlt, false);
  49.             __CFRunLoopTimerFireTSRUnlock();
  50.             if (!_CFExecutableLinkedOnOrAfter(CFSystemVersionLion)) {
  51.                 // Normally we don't do this on behalf of clients, but for
  52.                 // backwards compatibility due to the change in timer handling...
  53.                 if (rl != CFRunLoopGetCurrent()) CFRunLoopWakeUp(rl);
  54.             }
  55.     }
  56.         if (NULL != rlm) {
  57.         __CFRunLoopModeUnlock(rlm);
  58.     }
  59.     }
  60.     __CFRunLoopUnlock(rl);
  61. }
  62. 复制代码

__CFRunLoopFindMode

  1. static CFRunLoopModeRef __CFRunLoopFindMode(CFRunLoopRef rl, CFStringRef 
  2.     modeName, Boolean create) {
  3.     CHECK_FOR_FORK();
  4.     CFRunLoopModeRef rlm;
  5.     struct __CFRunLoopMode srlm;
  6.     memset(&srlm, 0, sizeof(srlm));
  7.     _CFRuntimeSetInstanceTypeIDAndIsa(&srlm, __kCFRunLoopModeTypeID);
  8.     srlm._name = modeName;
  9.     rlm = (CFRunLoopModeRef)CFSetGetValue(rl->_modes, &srlm);
  10.     if (NULL != rlm) {
  11.     __CFRunLoopModeLock(rlm);
  12.     return rlm;
  13.     }
  14.     if (!create) {
  15.     return NULL;
  16.     }
  17.     rlm = (CFRunLoopModeRef)_CFRuntimeCreateInstance(kCFAllocatorSystemDefault,
  18.      __kCFRunLoopModeTypeID, sizeof(struct __CFRunLoopMode) - sizeof(
  19.         CFRuntimeBase), NULL);
  20.     if (NULL == rlm) {
  21.     return NULL;
  22.     }
  23.     __CFRunLoopLockInit(&rlm->_lock);
  24.     rlm->_name = CFStringCreateCopy(kCFAllocatorSystemDefault, modeName);
  25.     rlm->_stopped = false;
  26.     rlm->_portToV1SourceMap = NULL;
  27.     rlm->_sources0 = NULL;
  28.     rlm->_sources1 = NULL;
  29.     rlm->_observers = NULL;
  30.     rlm->_timers = NULL;
  31.     rlm->_observerMask = 0;
  32.     rlm->_portSet = __CFPortSetAllocate();
  33.     rlm->_timerSoftDeadline = UINT64_MAX;
  34.     rlm->_timerHardDeadline = UINT64_MAX;
  35.      
  36.     kern_return_t ret = KERN_SUCCESS;
  37.     //1
  38. #if USE_DISPATCH_SOURCE_FOR_TIMERS
  39.     rlm->_timerFired = false;
  40.     rlm->_queue = _dispatch_runloop_root_queue_create_4CF("Run Loop Mode Queue"
  41.     , 0);
  42.     mach_port_t queuePort = _dispatch_runloop_root_queue_get_port_4CF(rlm->
  43.         _queue);
  44.     if (queuePort == MACH_PORT_NULL) CRASH("*** Unable to create run loop mode 
  45.     queue port. (%d) ***", -1);
  46.     rlm->_timerSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0
  47.         , rlm->_queue);
  48.      
  49.     __block Boolean *timerFiredPointer = &(rlm->_timerFired);
  50.     dispatch_source_set_event_handler(rlm->_timerSource, ^{
  51.         *timerFiredPointer = true;
  52.     });
  53.      
  54.     // Set timer to far out there. The unique leeway makes this timer easy to spot in debug output.
  55.     _dispatch_source_set_runloop_timer_4CF(rlm->_timerSource, 
  56.         DISPATCH_TIME_FOREVER, DISPATCH_TIME_FOREVER, 321);
  57.     dispatch_resume(rlm->_timerSource);
  58.      
  59.     ret = __CFPortSetInsert(queuePort, rlm->_portSet);
  60.     if (KERN_SUCCESS != ret) CRASH("*** Unable to insert timer port into port 
  61.     set. (%d) ***", ret);
  62.      
  63. #endif
  64.     //1
  65. #if USE_MK_TIMER_TOO
  66.     rlm->_timerPort = mk_timer_create();
  67.     ret = __CFPortSetInsert(rlm->_timerPort, rlm->_portSet);
  68.     if (KERN_SUCCESS != ret) CRASH("*** Unable to insert timer port into port 
  69.     set. (%d) ***", ret);
  70. #endif
  71.      
  72.     ret = __CFPortSetInsert(rl->_wakeUpPort, rlm->_portSet);
  73.     if (KERN_SUCCESS != ret) CRASH("*** Unable to insert wake up port into 
  74.     port set. (%d) ***", ret);
  75.      
  76.     CFSetAddValue(rl->_modes, rlm);
  77.     CFRelease(rlm);
  78.     __CFRunLoopModeLock(rlm);   /* return mode locked */
  79.     return rlm;
  80. }  ``return` `rlm;``}`
  81. 复制代码

__CFRepositionTimerInMode

  1. static void __CFRepositionTimerInMode(CFRunLoopModeRef rlm, CFRunLoopTimerRef 
  2.     rlt, Boolean isInArray) {
  3.     if (!rlt) return;
  4.      
  5.     CFMutableArrayRef timerArray = rlm->_timers;
  6.     if (!timerArray) return;
  7.     Boolean found = false;
  8.      
  9.     // If we know in advance that the timer is not in the array (just being added now) then we can skip this search
  10.     if (isInArray) {
  11.         CFIndex idx = CFArrayGetFirstIndexOfValue(timerArray, CFRangeMake(0, 
  12.             CFArrayGetCount(timerArray)), rlt);
  13.         if (kCFNotFound != idx) {
  14.             CFRetain(rlt);
  15.             CFArrayRemoveValueAtIndex(timerArray, idx);
  16.             found = true;
  17.         }
  18.     }
  19.     if (!found && isInArray) return;
  20.     CFIndex newIdx = __CFRunLoopInsertionIndexInTimerArray(timerArray, rlt);
  21.    //timer开始计时
  22.     CFArrayInsertValueAtIndex(timerArray, newIdx, rlt);
  23.     __CFArmNextTimerInMode(rlm, rlt->_runLoop);
  24.     if (isInArray) CFRelease(rlt);
  25. }
  26. 复制代码

__CFArmNextTimerInMode

  1. static void __CFArmNextTimerInMode(CFRunLoopModeRef rlm, CFRunLoopRef rl) {   
  2.     uint64_t nextHardDeadline = UINT64_MAX;
  3.     uint64_t nextSoftDeadline = UINT64_MAX;
  4.     if (rlm->_timers) {
  5.         // Look at the list of timers. We will calculate two TSR values; the 
  6. //next soft and next hard deadline.
  7.         // The next soft deadline is the first time we can fire any timer. 
  8. //This is the fire date of the first timer in our sorted list of timers.
  9.         // The next hard deadline is the last time at which we can fire the 
  10. //timer before we've moved out of the allowable tolerance of the timers in our list.
  11.         for (CFIndex idx = 0, cnt = CFArrayGetCount(rlm->_timers); idx < cnt; 
  12. idx++) {
  13.             CFRunLoopTimerRef t = (CFRunLoopTimerRef)CFArrayGetValueAtIndex(rlm
  14.     ->_timers , idx);
  15.             // discount timers currently firing
  16.             if (__CFRunLoopTimerIsFiring(t)) continue;
  17.              
  18.             int32_t err = CHECKINT_NO_ERROR;
  19.             uint64_t oneTimerSoftDeadline = t->_fireTSR;
  20.             uint64_t oneTimerHardDeadline = check_uint64_add(t->_fireTSR, 
  21.     __CFTimeIntervalToTSR(t->_tolerance), &err);
  22.             if (err != CHECKINT_NO_ERROR) oneTimerHardDeadline = UINT64_MAX;
  23.              
  24.             // We can stop searching if the soft deadline for this timer exceeds the current hard deadline. Otherwise, later timers with lower tolerance could still have earlier hard deadlines.
  25.             if (oneTimerSoftDeadline > nextHardDeadline) {
  26.                 break;
  27.             }
  28.              
  29.             if (oneTimerSoftDeadline < nextSoftDeadline) {
  30.                 nextSoftDeadline = oneTimerSoftDeadline;
  31.             }
  32.              
  33.             if (oneTimerHardDeadline < nextHardDeadline) {
  34.                 nextHardDeadline = oneTimerHardDeadline;
  35.             }
  36.         }
  37.          
  38.         if (nextSoftDeadline < UINT64_MAX && (nextHardDeadline != rlm->
  39.     _timerHardDeadline || nextSoftDeadline != rlm->_timerSoftDeadline)) {
  40.             if (CFRUNLOOP_NEXT_TIMER_ARMED_ENABLED()) {
  41.                 CFRUNLOOP_NEXT_TIMER_ARMED((unsigned long)(nextSoftDeadline - 
  42.     mach_absolute_time()));
  43.             }
  44. #if USE_DISPATCH_SOURCE_FOR_TIMERS
  45.             // We're going to hand off the range of allowable timer fire date 
  46. //to dispatch and let it fire when appropriate for the system.
  47.             uint64_t leeway = __CFTSRToNanoseconds(nextHardDeadline - 
  48.     nextSoftDeadline);
  49.             dispatch_time_t deadline = __CFTSRToDispatchTime(nextSoftDeadline);
  50. #if USE_MK_TIMER_TOO
  51. //leeway表示timer的偏差，如果_tolerance(>=0)为0，则leeway等于0
  52.             if (leeway > 0) {
  53. //GCD timer
  54.                 // Only use the dispatch timer if we have any leeway
  55.                 // <rdar://problem/14447675>
  56.                  
  57.                 // Cancel the mk timer
  58.                 if (rlm->_mkTimerArmed && rlm->_timerPort) {
  59.                     AbsoluteTime dummy;
  60.                     mk_timer_cancel(rlm->_timerPort, &dummy);
  61.                     rlm->_mkTimerArmed = false;
  62.                 }
  63.                  
  64.                 // Arm the dispatch timer
  65.                 _dispatch_source_set_runloop_timer_4CF(rlm->_timerSource, 
  66.     deadline, DISPATCH_TIME_FOREVER, leeway);
  67.                 rlm->_dispatchTimerArmed = true;
  68.             } else {
  69. //mk timer，实际中是这种情况
  70.                 // Cancel the dispatch timer
  71.                 if (rlm->_dispatchTimerArmed) {
  72.                     // Cancel the dispatch timer
  73.                     _dispatch_source_set_runloop_timer_4CF(rlm->_timerSource, 
  74.     DISPATCH_TIME_FOREVER, DISPATCH_TIME_FOREVER, 888);
  75.                     rlm->_dispatchTimerArmed = false;
  76.                 }
  77.                  
  78.                 // Arm the mk timer
  79.                 if (rlm->_timerPort) {
  80. //timer开始运行
  81.                     mk_timer_arm(rlm->_timerPort, __CFUInt64ToAbsoluteTime(
  82.     nextSoftDeadline));
  83.                     rlm->_mkTimerArmed = true;
  84.                 }
  85.             }
  86. #else
  87.             _dispatch_source_set_runloop_timer_4CF(rlm->_timerSource, deadline,
  88.  DISPATCH_TIME_FOREVER, leeway);
  89. #endif
  90. #else
  91.             if (rlm->_timerPort) {
  92.                 mk_timer_arm(rlm->_timerPort, __CFUInt64ToAbsoluteTime(
  93.     nextSoftDeadline));
  94.             }
  95. #endif
  96.         } else if (nextSoftDeadline == UINT64_MAX) {
  97.             // Disarm the timers - there is no timer scheduled
  98.              
  99.             if (rlm->_mkTimerArmed && rlm->_timerPort) {
  100.                 AbsoluteTime dummy;
  101.                 mk_timer_cancel(rlm->_timerPort, &dummy);
  102.                 rlm->_mkTimerArmed = false;
  103.             }
  104.              
  105. #if USE_DISPATCH_SOURCE_FOR_TIMERS
  106.             if (rlm->_dispatchTimerArmed) {
  107.                 _dispatch_source_set_runloop_timer_4CF(rlm->_timerSource, 
  108.     DISPATCH_TIME_FOREVER, DISPATCH_TIME_FOREVER, 333);
  109.                 rlm->_dispatchTimerArmed = false;
  110.             }
  111. #endif
  112.         }
  113.     }
  114.     rlm->_timerHardDeadline = nextHardDeadline;
  115.     rlm->_timerSoftDeadline = nextSoftDeadline;
  116. }
  117. 复制代码

_CFRunLoopGet0

  1. CF_EXPORT CFRunLoopRef _CFRunLoopGet0(pthread_t t) {
  2.     //判断t是否是传的空，如果是当成主线程处理
  3.     if (pthread_equal(t, kNilPthreadT)) {
  4.         t = pthread_main_thread_np();
  5.     }
  6.     __CFSpinLock(&loopsLock);
  7. //__CFRunLoops是全局存储线程和runloop关系的字典
  8.     if (!__CFRunLoops) {
  9. //__CFRunLoop第一次初始化
  10.         __CFSpinUnlock(&loopsLock);
  11. //初始化__CFRunLoop
  12.     CFMutableDictionaryRef dict = CFDictionaryCreateMutable(
  13.         kCFAllocatorSystemDefault, 0, NULL, &kCFTypeDictionaryValueCallBacks);
  14. //生成主线程对应runloop
  15.     CFRunLoopRef mainLoop = __CFRunLoopCreate(pthread_main_thread_np());
  16. //存储到__CFRunLoop字典中
  17.     CFDictionarySetValue(dict, pthreadPointer(pthread_main_thread_np()), mainLoop);
  18.     if (!OSAtomicCompareAndSwapPtrBarrier(NULL, dict, (void * volatile *)&
  19.     __CFRunLoops)) {
  20.         CFRelease(dict);
  21.     }
  22.     CFRelease(mainLoop);
  23.         __CFSpinLock(&loopsLock);
  24.     }
  25. //找到线程t对应的runloop
  26.     CFRunLoopRef loop = (CFRunLoopRef)CFDictionaryGetValue(__CFRunLoops, 
  27.         pthreadPointer(t));
  28.     __CFSpinUnlock(&loopsLock);
  29.     if (!loop) {
  30. //没有找到，创建一个
  31.     CFRunLoopRef newLoop = __CFRunLoopCreate(t);
  32.         __CFSpinLock(&loopsLock);
  33. //??????
  34.     loop = (CFRunLoopRef)CFDictionaryGetValue(__CFRunLoops, pthreadPointer(t));
  35.     if (!loop) {
  36. //保存到全局字典中
  37.         CFDictionarySetValue(__CFRunLoops, pthreadPointer(t), newLoop);
  38.         loop = newLoop;
  39.     }
  40.         // don't release run loops inside the loopsLock, because 
  41.         //CFRunLoopDeallocate may end up taking it --> -->
  42.         __CFSpinUnlock(&loopsLock);
  43.     CFRelease(newLoop);
  44.     }
  45.     if (pthread_equal(t, pthread_self())) {
  46.         _CFSetTSD(__CFTSDKeyRunLoop, (void *)loop, NULL);
  47.         if (0 == _CFGetTSD(__CFTSDKeyRunLoopCntr)) {
  48.             _CFSetTSD(__CFTSDKeyRunLoopCntr, (void *)(
  49.                 PTHREAD_DESTRUCTOR_ITERATIONS-1), (void (*)(void *))
  50.                 __CFFinalizeRunLoop);
  51.         }
  52.     }
  53.     return loop;
  54. }
  55. 复制代码

转载于:https://juejin.im/post/5b6817aee51d4519610e44f7

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