corelink_exception.py

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"""
    @file corelink_exception.py
    @brief Handles the underlying DLL error messages
"""
import ctypes
import corelink_const

class CorelinkException(Exception):
    """
        Gets the error message for the corresponding error ID.
        @param error_id id returned by call to the dll.
        @exception Throws a CorelinkException for the error_id if error_id != 0.
    """
    def __init__(self,*arg):
        if len(arg)==2:
            self.update(arg[0],arg[1])
        if len(arg)==1:
            rhs = arg[0]
            self.update(rhs.msg,rhs.code)
        super().__init__(self.error_msg)
    def update(self,msg,code):
        """
            Update the Parameters
        """
        self.msg = msg
        self.code = code
        self.error_msg = corelink_const.ERROR_CODE_STRING[code] + ": " + msg
    @staticmethod
    def get_dll_exception(error_id_ctypes):
        """
            Handle DLL Exception
        """
        error_id = error_id_ctypes.value
        if error_id==0:
            return
        error_len = ctypes.c_int()
        corelink_const.LIB.getError.argtypes = [ctypes.POINTER(ctypes.c_int),
                                                ctypes.POINTER(ctypes.c_int)]
        corelink_const.LIB.getError.restype = ctypes.c_char_p
        msg = corelink_const.LIB.getError(ctypes.byref(error_id_ctypes),
                                            ctypes.byref(error_len)).decode('UTF-8')
        if error_len.value ==0:
            raise CorelinkException("No message remaining. Client closed",
                                    corelink_const.ERROR_CODES['ERROR_CODE_NONE'])
        raise CorelinkException(msg[:error_len.value -1],ord(msg[error_len.value -1]))