func suiteMethod()

in common/rpc_service.go [358:420]
45 lines of code
14 McCabe index (conditional complexity)

func suiteMethod(method reflect.Method) *MethodType {
	mtype := method.Type
	mname := method.Name
	inNum := mtype.NumIn()
	outNum := mtype.NumOut()

	// Method must be exported.
	if method.PkgPath != "" {
		return nil
	}

	var (
		replyType, ctxType reflect.Type
		argsType           []reflect.Type
	)

	// Reference is used to define service reference, and method with prefix 'XXX' is generated by triple pb tool.
	// SetGRPCServer is used for pb reflection.
	// They should not to be checked.
	if mname == "Reference" || mname == "SetGRPCServer" || strings.HasPrefix(mname, "XXX") {
		return nil
	}

	if outNum != 1 && outNum != 2 {
		logger.Warnf("method %s of mtype %v has wrong number of in out parameters %d; needs exactly 1/2",
			mname, mtype.String(), outNum)
		return nil
	}

	// The latest return type of the method must be error.
	if returnType := mtype.Out(outNum - 1); returnType != typeOfError {
		logger.Debugf(`"%s" method will not be exported because its last return type %v doesn't have error`, mname, returnType)
		return nil
	}

	// replyType
	if outNum == 2 {
		replyType = mtype.Out(0)
		if !isExportedOrBuiltinType(replyType) {
			logger.Errorf("reply type of method %s not exported{%v}", mname, replyType)
			return nil
		}
	}

	index := 1

	// ctxType
	if inNum > 1 && mtype.In(1).String() == "context.Context" {
		ctxType = mtype.In(1)
		index = 2
	}

	for ; index < inNum; index++ {
		argsType = append(argsType, mtype.In(index))
		// need not be a pointer.
		if !isExportedOrBuiltinType(mtype.In(index)) {
			logger.Errorf("argument type of method %q is not exported %v", mname, mtype.In(index))
			return nil
		}
	}

	return &MethodType{method: method, argsType: argsType, replyType: replyType, ctxType: ctxType}
}