list_ports_osx.py 文件源码

def GetParentDeviceByType(device, parent_type):
    """ Find the first parent of a device that implements the parent_type
        @param IOService Service to inspect
        @return Pointer to the parent type, or None if it was not found.
    """
    # First, try to walk up the IOService tree to find a parent of this device that is a IOUSBDevice.
    parent_type = parent_type.encode('mac_roman')
    while IORegistryEntryGetName(device) != parent_type:
        parent = ctypes.c_void_p()
        response = iokit.IORegistryEntryGetParentEntry(
                device,
                "IOService".encode("mac_roman"),
                ctypes.byref(parent))
        # If we weren't able to find a parent for the device, we're done.
        if response != 0:
            return None
        device = parent
    return device