dumbdbm.py 文件源码

def open(file, flag=None, mode=0666):
    """Open the database file, filename, and return corresponding object.

    The flag argument, used to control how the database is opened in the
    other DBM implementations, is ignored in the dumbdbm module; the
    database is always opened for update, and will be created if it does
    not exist.

    The optional mode argument is the UNIX mode of the file, used only when
    the database has to be created.  It defaults to octal code 0666 (and
    will be modified by the prevailing umask).

    """
    # flag argument is currently ignored

    # Modify mode depending on the umask
    try:
        um = _os.umask(0)
        _os.umask(um)
    except AttributeError:
        pass
    else:
        # Turn off any bits that are set in the umask
        mode = mode & (~um)

    return _Database(file, mode)