Does method + (instancetype)classInfoWithClass:(Class)cls; in YYClassInfo thread-safe ?

[duduWang20]

• (instancetype)classInfoWithClass:(Class)cls {
  if (!cls) return nil;
  static CFMutableDictionaryRef classCache;
  static CFMutableDictionaryRef metaCache;
  static dispatch_once_t onceToken;
  static dispatch_semaphore_t lock;
  dispatch_once(&onceToken, ^{
  classCache = CFDictionaryCreateMutable(CFAllocatorGetDefault(), 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
  metaCache = CFDictionaryCreateMutable(CFAllocatorGetDefault(), 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
  lock = dispatch_semaphore_create(1);
  });
  dispatch_semaphore_wait(lock, DISPATCH_TIME_FOREVER);
  YYClassInfo *info = CFDictionaryGetValue(class_isMetaClass(cls) ? metaCache : classCache, (__bridge const void *)(cls));
  if (info && info->_needUpdate) {
  [info _update];
  }
  dispatch_semaphore_signal(lock);
  if (!info) {
  info = [[YYClassInfo alloc] initWithClass:cls];
  if (info) {
  dispatch_semaphore_wait(lock, DISPATCH_TIME_FOREVER);
  CFDictionarySetValue(info.isMeta ? metaCache : classCache, (__bridge const void *)(cls), (__bridge const void *)(info));
  dispatch_semaphore_signal(lock);
  }
  }
  return info;
  }

[duduWang20]

@ibireme