basic.py 文件源码

def _apply_operation_to_mode(user, operator, mode_to_apply, current_mode):
        if operator == '=':
            if user == 'u':
                mask = stat.S_IRWXU | stat.S_ISUID
            elif user == 'g':
                mask = stat.S_IRWXG | stat.S_ISGID
            elif user == 'o':
                mask = stat.S_IRWXO | stat.S_ISVTX

            # mask out u, g, or o permissions from current_mode and apply new permissions
            inverse_mask = mask ^ PERM_BITS
            new_mode = (current_mode & inverse_mask) | mode_to_apply
        elif operator == '+':
            new_mode = current_mode | mode_to_apply
        elif operator == '-':
            new_mode = current_mode - (current_mode & mode_to_apply)
        return new_mode