func()

in hessian.go [110:172]

• 49 lines of code
• 13 McCabe index (conditional complexity)

func (h *HessianCodec) ReadHeader(header *DubboHeader) error {
	var err error

	if h.reader.Size() < HEADER_LENGTH {
		return ErrHeaderNotEnough
	}
	buf, err := h.reader.Peek(HEADER_LENGTH)
	if err != nil { // this is impossible
		return perrors.WithStack(err)
	}
	_, err = h.reader.Discard(HEADER_LENGTH)
	if err != nil { // this is impossible
		return perrors.WithStack(err)
	}

	//// read header

	if buf[0] != MAGIC_HIGH && buf[1] != MAGIC_LOW {
		return ErrIllegalPackage
	}

	// Header{serialization id(5 bit), event, two way, req/response}
	if header.SerialID = buf[2] & SERIAL_MASK; header.SerialID == Zero {
		return perrors.Errorf("serialization ID:%v", header.SerialID)
	}

	headerFlag := buf[2] & FLAG_EVENT
	if headerFlag != Zero {
		header.Type |= PackageHeartbeat
	}
	headerFlag = buf[2] & FLAG_REQUEST
	if headerFlag != Zero {
		header.Type |= PackageRequest
		headerFlag = buf[2] & FLAG_TWOWAY
		if headerFlag != Zero {
			header.Type |= PackageRequest_TwoWay
		}
	} else {
		header.Type |= PackageResponse
		header.ResponseStatus = buf[3]
		if header.ResponseStatus != Response_OK {
			header.Type |= PackageResponse_Exception
		}
	}

	// Header{req id}
	header.ID = int64(binary.BigEndian.Uint64(buf[4:]))

	// Header{body len}
	header.BodyLen = int(binary.BigEndian.Uint32(buf[12:]))
	if header.BodyLen < 0 {
		return ErrIllegalPackage
	}

	h.pkgType = header.Type
	h.bodyLen = header.BodyLen

	if h.reader.Buffered() < h.bodyLen {
		return ErrBodyNotEnough
	}

	return perrors.WithStack(err)
}