list_ports_osx.py 文件源码

def get_int_property(device_type, property, cf_number_type):
    """
    Search the given device for the specified string property

    @param device_type Device to search
    @param property String to search for
    @param cf_number_type CFType number

    @return Python string containing the value, or None if not found.
    """
    key = cf.CFStringCreateWithCString(
            kCFAllocatorDefault,
            property.encode("mac_roman"),
            kCFStringEncodingMacRoman)

    CFContainer = iokit.IORegistryEntryCreateCFProperty(
            device_type,
            key,
            kCFAllocatorDefault,
            0)

    if CFContainer:
        if (cf_number_type == kCFNumberSInt32Type):
            number = ctypes.c_uint32()
        elif (cf_number_type == kCFNumberSInt16Type):
            number = ctypes.c_uint16()
        cf.CFNumberGetValue(CFContainer, cf_number_type, ctypes.byref(number))
        cf.CFRelease(CFContainer)
        return number.value
    return None