dbm.py 文件源码

def open(filename, flag='r', mode=0666):
    "open a DBM database"
    if not isinstance(filename, str):
        raise TypeError("expected string")

    openflag = 0

    try:
        openflag = {
            'r': os.O_RDONLY,
            'rw': os.O_RDWR,
            'w': os.O_RDWR | os.O_CREAT,
            'c': os.O_RDWR | os.O_CREAT,
            'n': os.O_RDWR | os.O_CREAT | os.O_TRUNC,
            }[flag]
    except KeyError:
        raise error("arg 2 to open should be 'r', 'w', 'c', or 'n'")

    a_db = getattr(lib, funcs['open'])(filename, openflag, mode)
    if a_db == 0:
        raise error("Could not open file %s.db" % filename)
    return dbm(a_db)