reactnative调研

/**
  * This function parses the exported methods inside RCTBridgeModules and
  * generates an array of arrays of RCTModuleMethod objects, keyed
  * by module index.
  */
  static RCTSparseArray *RCTExportedMethodsByModuleID(void)
  {
  static RCTSparseArray *methodsByModuleID;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
   
  Dl_info info;
  dladdr(&RCTExportedMethodsByModuleID, &info);
   
  #ifdef __LP64__
  typedef uint64_t RCTExportValue;
  typedef struct section_64 RCTExportSection;
  #define RCTGetSectByNameFromHeader getsectbynamefromheader_64
  #else
  typedef uint32_t RCTExportValue;
  typedef struct section RCTExportSection;
  #define RCTGetSectByNameFromHeader getsectbynamefromheader
  #endif
   
  const RCTExportValue mach_header = (RCTExportValue)info.dli_fbase;
  const RCTExportSection *section = RCTGetSectByNameFromHeader((void *)mach_header, "__DATA", "RCTExport");
   
  if (section == NULL) {
  return;
  }
   
  NSArray *classes = RCTBridgeModuleClassesByModuleID();
  NSMutableDictionary *methodsByModuleClassName = [NSMutableDictionary dictionaryWithCapacity:[classes count]];
   
  for (RCTExportValue addr = section->offset;
  addr < section->offset + section->size;
  addr += sizeof(const char **) * 2) {
   
  // Get data entry
  const char **entries = (const char **)(mach_header + addr);
   
  // Create method
  RCTModuleMethod *moduleMethod =
  [[RCTModuleMethod alloc] initWithMethodName:@(entries[0])
  JSMethodName:strlen(entries[1]) ? @(entries[1]) : nil];
   
  // Cache method
  NSArray *methods = methodsByModuleClassName[moduleMethod.moduleClassName];
  methodsByModuleClassName[moduleMethod.moduleClassName] =
  methods ? [methods arrayByAddingObject:moduleMethod] : @[moduleMethod];
  }
   
  methodsByModuleID = [[RCTSparseArray alloc] initWithCapacity:[classes count]];
  [classes enumerateObjectsUsingBlock:^(Class moduleClass, NSUInteger moduleID, BOOL *stop) {
  methodsByModuleID[moduleID] = methodsByModuleClassName[NSStringFromClass(moduleClass)];
  }];
  });
   
  return methodsByModuleID;
  }
原文地址:https://www.cnblogs.com/feng9exe/p/6694705.html