transport.py 文件源码

def read(self, timeout=0):
        if self.usb_inp is not None:
            try:
                ep_addr = self.usb_inp.getAddress()
                frame = self.usb_dev.bulkRead(ep_addr, 300, timeout)
            except libusb.USBErrorTimeout:
                raise IOError(errno.ETIMEDOUT, os.strerror(errno.ETIMEDOUT))
            except libusb.USBErrorNoDevice:
                raise IOError(errno.ENODEV, os.strerror(errno.ENODEV))
            except libusb.USBError as error:
                log.error("%r", error)
                raise IOError(errno.EIO, os.strerror(errno.EIO))

            if len(frame) == 0:
                log.error("bulk read returned zero data")
                raise IOError(errno.EIO, os.strerror(errno.EIO))

            frame = bytearray(frame)
            log.log(logging.DEBUG-1, "<<< %s", hexlify(frame))
            return frame