import gdb


class KapiFilesystemDeviceNumberPrinter(gdb.ValuePrinter):

    def __init__(self, val):
        self.__val = val

    def to_string(self):
        try:
            major = int(self.__val["major"])
            minor = int(self.__val["minor"])
            return f"{major}:{minor}"
        except (gdb.error, AttributeError):
            return "<device_number ?>"

    def children(self):
        yield ("major", self.__val["major"])
        yield ("minor", self.__val["minor"])

    def display_hint(self):
        return None