lfs_shadow.py 文件源码

def __init__(self, args, lfs_globals):
        super().__init__(args, lfs_globals)
        (head, tail) = os.path.split(args.shadow_file)
        assert os.path.isdir(head), 'No such directory %s' % head

        try:
            probe = tempfile.TemporaryFile(dir=head)
            probe.close()
        except OSError as e:
            raise RuntimeError('%s is not writeable' % head)

        if os.path.isfile(args.shadow_file):
            fd = os.open(args.shadow_file, os.O_RDWR)
        else:
            fd = os.open(args.shadow_file, os.O_RDWR | os.O_CREAT)
            size = lfs_globals['nvm_bytes_total']
            os.ftruncate(fd, size)
        self._shadow_fd = fd

        # Compare node requirements to actual file size
        statinfo = os.stat(args.shadow_file)
        assert self._S_IFREG_URW == self._S_IFREG_URW & statinfo.st_mode, \
            '%s is not RW'
        assert statinfo.st_size >= lfs_globals['nvm_bytes_total']
        args.aperture_base = 0
        args.aperture_size = statinfo.st_size
        args.addr_mode = self._MODE_FALLBACK
        super().__init__(args, lfs_globals)

    # open(), create(), release() only do caching as handled by superclass