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cpython/Lib/tarfile.py

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#!/usr/bin/env python3
#-------------------------------------------------------------------
# tarfile.py
#-------------------------------------------------------------------
# Copyright (C) 2002 Lars Gustaebel <lars@gustaebel.de>
# All rights reserved.
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without
# restriction, including without limitation the rights to use,
# copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following
# conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
# OTHER DEALINGS IN THE SOFTWARE.
#
"""Read from and write to tar format archives.
"""
version = "0.9.0"
__author__ = "Lars Gust\u00e4bel (lars@gustaebel.de)"
__date__ = "$Date: 2011-02-25 17:42:01 +0200 (Fri, 25 Feb 2011) $"
__cvsid__ = "$Id: tarfile.py 88586 2011-02-25 15:42:01Z marc-andre.lemburg $"
__credits__ = "Gustavo Niemeyer, Niels Gust\u00e4bel, Richard Townsend."
#---------
# Imports
#---------
import sys
import os
import io
import shutil
import stat
import time
import struct
import copy
import re
try:
import grp, pwd
except ImportError:
grp = pwd = None
# os.symlink on Windows prior to 6.0 raises NotImplementedError
symlink_exception = (AttributeError, NotImplementedError)
try:
# WindowsError (1314) will be raised if the caller does not hold the
# SeCreateSymbolicLinkPrivilege privilege
symlink_exception += (WindowsError,)
except NameError:
pass
# from tarfile import *
__all__ = ["TarFile", "TarInfo", "is_tarfile", "TarError"]
from builtins import open as _open # Since 'open' is TarFile.open
#---------------------------------------------------------
# tar constants
#---------------------------------------------------------
NUL = b"\0" # the null character
BLOCKSIZE = 512 # length of processing blocks
RECORDSIZE = BLOCKSIZE * 20 # length of records
GNU_MAGIC = b"ustar \0" # magic gnu tar string
POSIX_MAGIC = b"ustar\x0000" # magic posix tar string
LENGTH_NAME = 100 # maximum length of a filename
LENGTH_LINK = 100 # maximum length of a linkname
LENGTH_PREFIX = 155 # maximum length of the prefix field
REGTYPE = b"0" # regular file
AREGTYPE = b"\0" # regular file
LNKTYPE = b"1" # link (inside tarfile)
SYMTYPE = b"2" # symbolic link
CHRTYPE = b"3" # character special device
BLKTYPE = b"4" # block special device
DIRTYPE = b"5" # directory
FIFOTYPE = b"6" # fifo special device
CONTTYPE = b"7" # contiguous file
GNUTYPE_LONGNAME = b"L" # GNU tar longname
GNUTYPE_LONGLINK = b"K" # GNU tar longlink
GNUTYPE_SPARSE = b"S" # GNU tar sparse file
XHDTYPE = b"x" # POSIX.1-2001 extended header
XGLTYPE = b"g" # POSIX.1-2001 global header
SOLARIS_XHDTYPE = b"X" # Solaris extended header
USTAR_FORMAT = 0 # POSIX.1-1988 (ustar) format
GNU_FORMAT = 1 # GNU tar format
PAX_FORMAT = 2 # POSIX.1-2001 (pax) format
DEFAULT_FORMAT = GNU_FORMAT
#---------------------------------------------------------
# tarfile constants
#---------------------------------------------------------
# File types that tarfile supports:
SUPPORTED_TYPES = (REGTYPE, AREGTYPE, LNKTYPE,
SYMTYPE, DIRTYPE, FIFOTYPE,
CONTTYPE, CHRTYPE, BLKTYPE,
GNUTYPE_LONGNAME, GNUTYPE_LONGLINK,
GNUTYPE_SPARSE)
# File types that will be treated as a regular file.
REGULAR_TYPES = (REGTYPE, AREGTYPE,
CONTTYPE, GNUTYPE_SPARSE)
# File types that are part of the GNU tar format.
GNU_TYPES = (GNUTYPE_LONGNAME, GNUTYPE_LONGLINK,
GNUTYPE_SPARSE)
# Fields from a pax header that override a TarInfo attribute.
PAX_FIELDS = ("path", "linkpath", "size", "mtime",
"uid", "gid", "uname", "gname")
# Fields from a pax header that are affected by hdrcharset.
PAX_NAME_FIELDS = {"path", "linkpath", "uname", "gname"}
# Fields in a pax header that are numbers, all other fields
# are treated as strings.
PAX_NUMBER_FIELDS = {
"atime": float,
"ctime": float,
"mtime": float,
"uid": int,
"gid": int,
"size": int
}
#---------------------------------------------------------
# Bits used in the mode field, values in octal.
#---------------------------------------------------------
S_IFLNK = 0o120000 # symbolic link
S_IFREG = 0o100000 # regular file
S_IFBLK = 0o060000 # block device
S_IFDIR = 0o040000 # directory
S_IFCHR = 0o020000 # character device
S_IFIFO = 0o010000 # fifo
TSUID = 0o4000 # set UID on execution
TSGID = 0o2000 # set GID on execution
TSVTX = 0o1000 # reserved
TUREAD = 0o400 # read by owner
TUWRITE = 0o200 # write by owner
TUEXEC = 0o100 # execute/search by owner
TGREAD = 0o040 # read by group
TGWRITE = 0o020 # write by group
TGEXEC = 0o010 # execute/search by group
TOREAD = 0o004 # read by other
TOWRITE = 0o002 # write by other
TOEXEC = 0o001 # execute/search by other
#---------------------------------------------------------
# initialization
#---------------------------------------------------------
if os.name in ("nt", "ce"):
ENCODING = "utf-8"
else:
ENCODING = sys.getfilesystemencoding()
#---------------------------------------------------------
# Some useful functions
#---------------------------------------------------------
def stn(s, length, encoding, errors):
"""Convert a string to a null-terminated bytes object.
"""
s = s.encode(encoding, errors)
return s[:length] + (length - len(s)) * NUL
def nts(s, encoding, errors):
"""Convert a null-terminated bytes object to a string.
"""
p = s.find(b"\0")
if p != -1:
s = s[:p]
return s.decode(encoding, errors)
def nti(s):
"""Convert a number field to a python number.
"""
# There are two possible encodings for a number field, see
# itn() below.
if s[0] in (0o200, 0o377):
n = 0
for i in range(len(s) - 1):
n <<= 8
n += s[i + 1]
if s[0] == 0o377:
n = -(256 ** (len(s) - 1) - n)
else:
try:
n = int(nts(s, "ascii", "strict") or "0", 8)
except ValueError:
raise InvalidHeaderError("invalid header")
return n
def itn(n, digits=8, format=DEFAULT_FORMAT):
"""Convert a python number to a number field.
"""
# POSIX 1003.1-1988 requires numbers to be encoded as a string of
# octal digits followed by a null-byte, this allows values up to
# (8**(digits-1))-1. GNU tar allows storing numbers greater than
# that if necessary. A leading 0o200 or 0o377 byte indicate this
# particular encoding, the following digits-1 bytes are a big-endian
# base-256 representation. This allows values up to (256**(digits-1))-1.
# A 0o200 byte indicates a positive number, a 0o377 byte a negative
# number.
if 0 <= n < 8 ** (digits - 1):
s = bytes("%0*o" % (digits - 1, n), "ascii") + NUL
elif format == GNU_FORMAT and -256 ** (digits - 1) <= n < 256 ** (digits - 1):
if n >= 0:
s = bytearray([0o200])
else:
s = bytearray([0o377])
n = 256 ** digits + n
for i in range(digits - 1):
s.insert(1, n & 0o377)
n >>= 8
else:
raise ValueError("overflow in number field")
return s
def calc_chksums(buf):
"""Calculate the checksum for a member's header by summing up all
characters except for the chksum field which is treated as if
it was filled with spaces. According to the GNU tar sources,
some tars (Sun and NeXT) calculate chksum with signed char,
which will be different if there are chars in the buffer with
the high bit set. So we calculate two checksums, unsigned and
signed.
"""
unsigned_chksum = 256 + sum(struct.unpack("148B", buf[:148]) + struct.unpack("356B", buf[156:512]))
signed_chksum = 256 + sum(struct.unpack("148b", buf[:148]) + struct.unpack("356b", buf[156:512]))
return unsigned_chksum, signed_chksum
def copyfileobj(src, dst, length=None):
"""Copy length bytes from fileobj src to fileobj dst.
If length is None, copy the entire content.
"""
if length == 0:
return
if length is None:
shutil.copyfileobj(src, dst)
return
BUFSIZE = 16 * 1024
blocks, remainder = divmod(length, BUFSIZE)
for b in range(blocks):
buf = src.read(BUFSIZE)
if len(buf) < BUFSIZE:
raise IOError("end of file reached")
dst.write(buf)
if remainder != 0:
buf = src.read(remainder)
if len(buf) < remainder:
raise IOError("end of file reached")
dst.write(buf)
return
filemode_table = (
((S_IFLNK, "l"),
(S_IFREG, "-"),
(S_IFBLK, "b"),
(S_IFDIR, "d"),
(S_IFCHR, "c"),
(S_IFIFO, "p")),
((TUREAD, "r"),),
((TUWRITE, "w"),),
((TUEXEC|TSUID, "s"),
(TSUID, "S"),
(TUEXEC, "x")),
((TGREAD, "r"),),
((TGWRITE, "w"),),
((TGEXEC|TSGID, "s"),
(TSGID, "S"),
(TGEXEC, "x")),
((TOREAD, "r"),),
((TOWRITE, "w"),),
((TOEXEC|TSVTX, "t"),
(TSVTX, "T"),
(TOEXEC, "x"))
)
def filemode(mode):
"""Convert a file's mode to a string of the form
-rwxrwxrwx.
Used by TarFile.list()
"""
perm = []
for table in filemode_table:
for bit, char in table:
if mode & bit == bit:
perm.append(char)
break
else:
perm.append("-")
return "".join(perm)
class TarError(Exception):
"""Base exception."""
pass
class ExtractError(TarError):
"""General exception for extract errors."""
pass
class ReadError(TarError):
"""Exception for unreadble tar archives."""
pass
class CompressionError(TarError):
"""Exception for unavailable compression methods."""
pass
class StreamError(TarError):
"""Exception for unsupported operations on stream-like TarFiles."""
pass
class HeaderError(TarError):
"""Base exception for header errors."""
pass
class EmptyHeaderError(HeaderError):
"""Exception for empty headers."""
pass
class TruncatedHeaderError(HeaderError):
"""Exception for truncated headers."""
pass
class EOFHeaderError(HeaderError):
"""Exception for end of file headers."""
pass
class InvalidHeaderError(HeaderError):
"""Exception for invalid headers."""
pass
class SubsequentHeaderError(HeaderError):
"""Exception for missing and invalid extended headers."""
pass
#---------------------------
# internal stream interface
#---------------------------
class _LowLevelFile:
"""Low-level file object. Supports reading and writing.
It is used instead of a regular file object for streaming
access.
"""
def __init__(self, name, mode):
mode = {
"r": os.O_RDONLY,
"w": os.O_WRONLY | os.O_CREAT | os.O_TRUNC,
}[mode]
if hasattr(os, "O_BINARY"):
mode |= os.O_BINARY
self.fd = os.open(name, mode, 0o666)
def close(self):
os.close(self.fd)
def read(self, size):
return os.read(self.fd, size)
def write(self, s):
os.write(self.fd, s)
class _Stream:
"""Class that serves as an adapter between TarFile and
a stream-like object. The stream-like object only
needs to have a read() or write() method and is accessed
blockwise. Use of gzip or bzip2 compression is possible.
A stream-like object could be for example: sys.stdin,
sys.stdout, a socket, a tape device etc.
_Stream is intended to be used only internally.
"""
def __init__(self, name, mode, comptype, fileobj, bufsize):
"""Construct a _Stream object.
"""
self._extfileobj = True
if fileobj is None:
fileobj = _LowLevelFile(name, mode)
self._extfileobj = False
if comptype == '*':
# Enable transparent compression detection for the
# stream interface
fileobj = _StreamProxy(fileobj)
comptype = fileobj.getcomptype()
self.name = name or ""
self.mode = mode
self.comptype = comptype
self.fileobj = fileobj
self.bufsize = bufsize
self.buf = b""
self.pos = 0
self.closed = False
try:
if comptype == "gz":
try:
import zlib
except ImportError:
raise CompressionError("zlib module is not available")
self.zlib = zlib
self.crc = zlib.crc32(b"")
if mode == "r":
self._init_read_gz()
self.exception = zlib.error
else:
self._init_write_gz()
elif comptype == "bz2":
try:
import bz2
except ImportError:
raise CompressionError("bz2 module is not available")
if mode == "r":
self.dbuf = b""
self.cmp = bz2.BZ2Decompressor()
self.exception = IOError
else:
self.cmp = bz2.BZ2Compressor()
elif comptype == "xz":
try:
import lzma
except ImportError:
raise CompressionError("lzma module is not available")
if mode == "r":
self.dbuf = b""
self.cmp = lzma.LZMADecompressor()
self.exception = lzma.LZMAError
else:
self.cmp = lzma.LZMACompressor()
elif comptype != "tar":
raise CompressionError("unknown compression type %r" % comptype)
except:
if not self._extfileobj:
self.fileobj.close()
self.closed = True
raise
def __del__(self):
if hasattr(self, "closed") and not self.closed:
self.close()
def _init_write_gz(self):
"""Initialize for writing with gzip compression.
"""
self.cmp = self.zlib.compressobj(9, self.zlib.DEFLATED,
-self.zlib.MAX_WBITS,
self.zlib.DEF_MEM_LEVEL,
0)
timestamp = struct.pack("<L", int(time.time()))
self.__write(b"\037\213\010\010" + timestamp + b"\002\377")
if self.name.endswith(".gz"):
self.name = self.name[:-3]
# RFC1952 says we must use ISO-8859-1 for the FNAME field.
self.__write(self.name.encode("iso-8859-1", "replace") + NUL)
def write(self, s):
"""Write string s to the stream.
"""
if self.comptype == "gz":
self.crc = self.zlib.crc32(s, self.crc)
self.pos += len(s)
if self.comptype != "tar":
s = self.cmp.compress(s)
self.__write(s)
def __write(self, s):
"""Write string s to the stream if a whole new block
is ready to be written.
"""
self.buf += s
while len(self.buf) > self.bufsize:
self.fileobj.write(self.buf[:self.bufsize])
self.buf = self.buf[self.bufsize:]
def close(self):
"""Close the _Stream object. No operation should be
done on it afterwards.
"""
if self.closed:
return
if self.mode == "w" and self.comptype != "tar":
self.buf += self.cmp.flush()
if self.mode == "w" and self.buf:
self.fileobj.write(self.buf)
self.buf = b""
if self.comptype == "gz":
# The native zlib crc is an unsigned 32-bit integer, but
# the Python wrapper implicitly casts that to a signed C
# long. So, on a 32-bit box self.crc may "look negative",
# while the same crc on a 64-bit box may "look positive".
# To avoid irksome warnings from the `struct` module, force
# it to look positive on all boxes.
self.fileobj.write(struct.pack("<L", self.crc & 0xffffffff))
self.fileobj.write(struct.pack("<L", self.pos & 0xffffFFFF))
if not self._extfileobj:
self.fileobj.close()
self.closed = True
def _init_read_gz(self):
"""Initialize for reading a gzip compressed fileobj.
"""
self.cmp = self.zlib.decompressobj(-self.zlib.MAX_WBITS)
self.dbuf = b""
# taken from gzip.GzipFile with some alterations
if self.__read(2) != b"\037\213":
raise ReadError("not a gzip file")
if self.__read(1) != b"\010":
raise CompressionError("unsupported compression method")
flag = ord(self.__read(1))
self.__read(6)
if flag & 4:
xlen = ord(self.__read(1)) + 256 * ord(self.__read(1))
self.read(xlen)
if flag & 8:
while True:
s = self.__read(1)
if not s or s == NUL:
break
if flag & 16:
while True:
s = self.__read(1)
if not s or s == NUL:
break
if flag & 2:
self.__read(2)
def tell(self):
"""Return the stream's file pointer position.
"""
return self.pos
def seek(self, pos=0):
"""Set the stream's file pointer to pos. Negative seeking
is forbidden.
"""
if pos - self.pos >= 0:
blocks, remainder = divmod(pos - self.pos, self.bufsize)
for i in range(blocks):
self.read(self.bufsize)
self.read(remainder)
else:
raise StreamError("seeking backwards is not allowed")
return self.pos
def read(self, size=None):
"""Return the next size number of bytes from the stream.
If size is not defined, return all bytes of the stream
up to EOF.
"""
if size is None:
t = []
while True:
buf = self._read(self.bufsize)
if not buf:
break
t.append(buf)
buf = "".join(t)
else:
buf = self._read(size)
self.pos += len(buf)
return buf
def _read(self, size):
"""Return size bytes from the stream.
"""
if self.comptype == "tar":
return self.__read(size)
c = len(self.dbuf)
while c < size:
buf = self.__read(self.bufsize)
if not buf:
break
try:
buf = self.cmp.decompress(buf)
except self.exception:
raise ReadError("invalid compressed data")
self.dbuf += buf
c += len(buf)
buf = self.dbuf[:size]
self.dbuf = self.dbuf[size:]
return buf
def __read(self, size):
"""Return size bytes from stream. If internal buffer is empty,
read another block from the stream.
"""
c = len(self.buf)
while c < size:
buf = self.fileobj.read(self.bufsize)
if not buf:
break
self.buf += buf
c += len(buf)
buf = self.buf[:size]
self.buf = self.buf[size:]
return buf
# class _Stream
class _StreamProxy(object):
"""Small proxy class that enables transparent compression
detection for the Stream interface (mode 'r|*').
"""
def __init__(self, fileobj):
self.fileobj = fileobj
self.buf = self.fileobj.read(BLOCKSIZE)
def read(self, size):
self.read = self.fileobj.read
return self.buf
def getcomptype(self):
if self.buf.startswith(b"\x1f\x8b\x08"):
return "gz"
elif self.buf[0:3] == b"BZh" and self.buf[4:10] == b"1AY&SY":
return "bz2"
elif self.buf.startswith((b"\x5d\x00\x00\x80", b"\xfd7zXZ")):
return "xz"
else:
return "tar"
def close(self):
self.fileobj.close()
# class StreamProxy
#------------------------
# Extraction file object
#------------------------
class _FileInFile(object):
"""A thin wrapper around an existing file object that
provides a part of its data as an individual file
object.
"""
def __init__(self, fileobj, offset, size, blockinfo=None):
self.fileobj = fileobj
self.offset = offset
self.size = size
self.position = 0
if blockinfo is None:
blockinfo = [(0, size)]
# Construct a map with data and zero blocks.
self.map_index = 0
self.map = []
lastpos = 0
realpos = self.offset
for offset, size in blockinfo:
if offset > lastpos:
self.map.append((False, lastpos, offset, None))
self.map.append((True, offset, offset + size, realpos))
realpos += size
lastpos = offset + size
if lastpos < self.size:
self.map.append((False, lastpos, self.size, None))
def seekable(self):
if not hasattr(self.fileobj, "seekable"):
# XXX gzip.GzipFile and bz2.BZ2File
return True
return self.fileobj.seekable()
def tell(self):
"""Return the current file position.
"""
return self.position
def seek(self, position):
"""Seek to a position in the file.
"""
self.position = position
def read(self, size=None):
"""Read data from the file.
"""
if size is None:
size = self.size - self.position
else:
size = min(size, self.size - self.position)
buf = b""
while size > 0:
while True:
data, start, stop, offset = self.map[self.map_index]
if start <= self.position < stop:
break
else:
self.map_index += 1
if self.map_index == len(self.map):
self.map_index = 0
length = min(size, stop - self.position)
if data:
self.fileobj.seek(offset + (self.position - start))
buf += self.fileobj.read(length)
else:
buf += NUL * length
size -= length
self.position += length
return buf
#class _FileInFile
class ExFileObject(object):
"""File-like object for reading an archive member.
Is returned by TarFile.extractfile().
"""
blocksize = 1024
def __init__(self, tarfile, tarinfo):
self.fileobj = _FileInFile(tarfile.fileobj,
tarinfo.offset_data,
tarinfo.size,
tarinfo.sparse)
self.name = tarinfo.name
self.mode = "r"
self.closed = False
self.size = tarinfo.size
self.position = 0
self.buffer = b""
def readable(self):
return True
def writable(self):
return False
def seekable(self):
return self.fileobj.seekable()
def read(self, size=None):
"""Read at most size bytes from the file. If size is not
present or None, read all data until EOF is reached.
"""
if self.closed:
raise ValueError("I/O operation on closed file")
buf = b""
if self.buffer:
if size is None:
buf = self.buffer
self.buffer = b""
else:
buf = self.buffer[:size]
self.buffer = self.buffer[size:]
if size is None:
buf += self.fileobj.read()
else:
buf += self.fileobj.read(size - len(buf))
self.position += len(buf)
return buf
# XXX TextIOWrapper uses the read1() method.
read1 = read
def readline(self, size=-1):
"""Read one entire line from the file. If size is present
and non-negative, return a string with at most that
size, which may be an incomplete line.
"""
if self.closed:
raise ValueError("I/O operation on closed file")
pos = self.buffer.find(b"\n") + 1
if pos == 0:
# no newline found.
while True:
buf = self.fileobj.read(self.blocksize)
self.buffer += buf
if not buf or b"\n" in buf:
pos = self.buffer.find(b"\n") + 1
if pos == 0:
# no newline found.
pos = len(self.buffer)
break
if size != -1:
pos = min(size, pos)
buf = self.buffer[:pos]
self.buffer = self.buffer[pos:]
self.position += len(buf)
return buf
def readlines(self):
"""Return a list with all remaining lines.
"""
result = []
while True:
line = self.readline()
if not line: break
result.append(line)
return result
def tell(self):
"""Return the current file position.
"""
if self.closed:
raise ValueError("I/O operation on closed file")
return self.position
def seek(self, pos, whence=io.SEEK_SET):
"""Seek to a position in the file.
"""
if self.closed:
raise ValueError("I/O operation on closed file")
if whence == io.SEEK_SET:
self.position = min(max(pos, 0), self.size)
elif whence == io.SEEK_CUR:
if pos < 0:
self.position = max(self.position + pos, 0)
else:
self.position = min(self.position + pos, self.size)
elif whence == io.SEEK_END:
self.position = max(min(self.size + pos, self.size), 0)
else:
raise ValueError("Invalid argument")
self.buffer = b""
self.fileobj.seek(self.position)
def close(self):
"""Close the file object.
"""
self.closed = True
def __iter__(self):
"""Get an iterator over the file's lines.
"""
while True:
line = self.readline()
if not line:
break
yield line
#class ExFileObject
#------------------
# Exported Classes
#------------------
class TarInfo(object):
"""Informational class which holds the details about an
archive member given by a tar header block.
TarInfo objects are returned by TarFile.getmember(),
TarFile.getmembers() and TarFile.gettarinfo() and are
usually created internally.
"""
__slots__ = ("name", "mode", "uid", "gid", "size", "mtime",
"chksum", "type", "linkname", "uname", "gname",
"devmajor", "devminor",
"offset", "offset_data", "pax_headers", "sparse",
"tarfile", "_sparse_structs", "_link_target")
def __init__(self, name=""):
"""Construct a TarInfo object. name is the optional name
of the member.
"""
self.name = name # member name
self.mode = 0o644 # file permissions
self.uid = 0 # user id
self.gid = 0 # group id
self.size = 0 # file size
self.mtime = 0 # modification time
self.chksum = 0 # header checksum
self.type = REGTYPE # member type
self.linkname = "" # link name
self.uname = "" # user name
self.gname = "" # group name
self.devmajor = 0 # device major number
self.devminor = 0 # device minor number
self.offset = 0 # the tar header starts here
self.offset_data = 0 # the file's data starts here
self.sparse = None # sparse member information
self.pax_headers = {} # pax header information
# In pax headers the "name" and "linkname" field are called
# "path" and "linkpath".
def _getpath(self):
return self.name
def _setpath(self, name):
self.name = name
path = property(_getpath, _setpath)
def _getlinkpath(self):
return self.linkname
def _setlinkpath(self, linkname):
self.linkname = linkname
linkpath = property(_getlinkpath, _setlinkpath)
def __repr__(self):
return "<%s %r at %#x>" % (self.__class__.__name__,self.name,id(self))
def get_info(self):
"""Return the TarInfo's attributes as a dictionary.
"""
info = {
"name": self.name,
"mode": self.mode & 0o7777,
"uid": self.uid,
"gid": self.gid,
"size": self.size,
"mtime": self.mtime,
"chksum": self.chksum,
"type": self.type,
"linkname": self.linkname,
"uname": self.uname,
"gname": self.gname,
"devmajor": self.devmajor,
"devminor": self.devminor
}
if info["type"] == DIRTYPE and not info["name"].endswith("/"):
info["name"] += "/"
return info
def tobuf(self, format=DEFAULT_FORMAT, encoding=ENCODING, errors="surrogateescape"):
"""Return a tar header as a string of 512 byte blocks.
"""
info = self.get_info()
if format == USTAR_FORMAT:
return self.create_ustar_header(info, encoding, errors)
elif format == GNU_FORMAT:
return self.create_gnu_header(info, encoding, errors)
elif format == PAX_FORMAT:
return self.create_pax_header(info, encoding)
else:
raise ValueError("invalid format")
def create_ustar_header(self, info, encoding, errors):
"""Return the object as a ustar header block.
"""
info["magic"] = POSIX_MAGIC
if len(info["linkname"]) > LENGTH_LINK:
raise ValueError("linkname is too long")
if len(info["name"]) > LENGTH_NAME:
info["prefix"], info["name"] = self._posix_split_name(info["name"])
return self._create_header(info, USTAR_FORMAT, encoding, errors)
def create_gnu_header(self, info, encoding, errors):
"""Return the object as a GNU header block sequence.
"""
info["magic"] = GNU_MAGIC
buf = b""
if len(info["linkname"]) > LENGTH_LINK:
buf += self._create_gnu_long_header(info["linkname"], GNUTYPE_LONGLINK, encoding, errors)
if len(info["name"]) > LENGTH_NAME:
buf += self._create_gnu_long_header(info["name"], GNUTYPE_LONGNAME, encoding, errors)
return buf + self._create_header(info, GNU_FORMAT, encoding, errors)
def create_pax_header(self, info, encoding):
"""Return the object as a ustar header block. If it cannot be
represented this way, prepend a pax extended header sequence
with supplement information.
"""
info["magic"] = POSIX_MAGIC
pax_headers = self.pax_headers.copy()
# Test string fields for values that exceed the field length or cannot
# be represented in ASCII encoding.
for name, hname, length in (
("name", "path", LENGTH_NAME), ("linkname", "linkpath", LENGTH_LINK),
("uname", "uname", 32), ("gname", "gname", 32)):
if hname in pax_headers:
# The pax header has priority.
continue
# Try to encode the string as ASCII.
try:
info[name].encode("ascii", "strict")
except UnicodeEncodeError:
pax_headers[hname] = info[name]
continue
if len(info[name]) > length:
pax_headers[hname] = info[name]
# Test number fields for values that exceed the field limit or values
# that like to be stored as float.
for name, digits in (("uid", 8), ("gid", 8), ("size", 12), ("mtime", 12)):
if name in pax_headers:
# The pax header has priority. Avoid overflow.
info[name] = 0
continue
val = info[name]
if not 0 <= val < 8 ** (digits - 1) or isinstance(val, float):
pax_headers[name] = str(val)
info[name] = 0
# Create a pax extended header if necessary.
if pax_headers:
buf = self._create_pax_generic_header(pax_headers, XHDTYPE, encoding)
else:
buf = b""
return buf + self._create_header(info, USTAR_FORMAT, "ascii", "replace")
@classmethod
def create_pax_global_header(cls, pax_headers):
"""Return the object as a pax global header block sequence.
"""
return cls._create_pax_generic_header(pax_headers, XGLTYPE, "utf-8")
def _posix_split_name(self, name):
"""Split a name longer than 100 chars into a prefix
and a name part.
"""
prefix = name[:LENGTH_PREFIX + 1]
while prefix and prefix[-1] != "/":
prefix = prefix[:-1]
name = name[len(prefix):]
prefix = prefix[:-1]
if not prefix or len(name) > LENGTH_NAME:
raise ValueError("name is too long")
return prefix, name
@staticmethod
def _create_header(info, format, encoding, errors):
"""Return a header block. info is a dictionary with file
information, format must be one of the *_FORMAT constants.
"""
parts = [
stn(info.get("name", ""), 100, encoding, errors),
itn(info.get("mode", 0) & 0o7777, 8, format),
itn(info.get("uid", 0), 8, format),
itn(info.get("gid", 0), 8, format),
itn(info.get("size", 0), 12, format),
itn(info.get("mtime", 0), 12, format),
b" ", # checksum field
info.get("type", REGTYPE),
stn(info.get("linkname", ""), 100, encoding, errors),
info.get("magic", POSIX_MAGIC),
stn(info.get("uname", ""), 32, encoding, errors),
stn(info.get("gname", ""), 32, encoding, errors),
itn(info.get("devmajor", 0), 8, format),
itn(info.get("devminor", 0), 8, format),
stn(info.get("prefix", ""), 155, encoding, errors)
]
buf = struct.pack("%ds" % BLOCKSIZE, b"".join(parts))
chksum = calc_chksums(buf[-BLOCKSIZE:])[0]
buf = buf[:-364] + bytes("%06o\0" % chksum, "ascii") + buf[-357:]
return buf
@staticmethod
def _create_payload(payload):
"""Return the string payload filled with zero bytes
up to the next 512 byte border.
"""
blocks, remainder = divmod(len(payload), BLOCKSIZE)
if remainder > 0:
payload += (BLOCKSIZE - remainder) * NUL
return payload
@classmethod
def _create_gnu_long_header(cls, name, type, encoding, errors):
"""Return a GNUTYPE_LONGNAME or GNUTYPE_LONGLINK sequence
for name.
"""
name = name.encode(encoding, errors) + NUL
info = {}
info["name"] = "././@LongLink"
info["type"] = type
info["size"] = len(name)
info["magic"] = GNU_MAGIC
# create extended header + name blocks.
return cls._create_header(info, USTAR_FORMAT, encoding, errors) + \
cls._create_payload(name)
@classmethod
def _create_pax_generic_header(cls, pax_headers, type, encoding):
"""Return a POSIX.1-2008 extended or global header sequence
that contains a list of keyword, value pairs. The values
must be strings.
"""
# Check if one of the fields contains surrogate characters and thereby
# forces hdrcharset=BINARY, see _proc_pax() for more information.
binary = False
for keyword, value in pax_headers.items():
try:
value.encode("utf-8", "strict")
except UnicodeEncodeError:
binary = True
break
records = b""
if binary:
# Put the hdrcharset field at the beginning of the header.
records += b"21 hdrcharset=BINARY\n"
for keyword, value in pax_headers.items():
keyword = keyword.encode("utf-8")
if binary:
# Try to restore the original byte representation of `value'.
# Needless to say, that the encoding must match the string.
value = value.encode(encoding, "surrogateescape")
else:
value = value.encode("utf-8")
l = len(keyword) + len(value) + 3 # ' ' + '=' + '\n'
n = p = 0
while True:
n = l + len(str(p))
if n == p:
break
p = n
records += bytes(str(p), "ascii") + b" " + keyword + b"=" + value + b"\n"
# We use a hardcoded "././@PaxHeader" name like star does
# instead of the one that POSIX recommends.
info = {}
info["name"] = "././@PaxHeader"
info["type"] = type
info["size"] = len(records)
info["magic"] = POSIX_MAGIC
# Create pax header + record blocks.
return cls._create_header(info, USTAR_FORMAT, "ascii", "replace") + \
cls._create_payload(records)
@classmethod
def frombuf(cls, buf, encoding, errors):
"""Construct a TarInfo object from a 512 byte bytes object.
"""
if len(buf) == 0:
raise EmptyHeaderError("empty header")
if len(buf) != BLOCKSIZE:
raise TruncatedHeaderError("truncated header")
if buf.count(NUL) == BLOCKSIZE:
raise EOFHeaderError("end of file header")
chksum = nti(buf[148:156])
if chksum not in calc_chksums(buf):
raise InvalidHeaderError("bad checksum")
obj = cls()
obj.name = nts(buf[0:100], encoding, errors)
obj.mode = nti(buf[100:108])
obj.uid = nti(buf[108:116])
obj.gid = nti(buf[116:124])
obj.size = nti(buf[124:136])
obj.mtime = nti(buf[136:148])
obj.chksum = chksum
obj.type = buf[156:157]
obj.linkname = nts(buf[157:257], encoding, errors)
obj.uname = nts(buf[265:297], encoding, errors)
obj.gname = nts(buf[297:329], encoding, errors)
obj.devmajor = nti(buf[329:337])
obj.devminor = nti(buf[337:345])
prefix = nts(buf[345:500], encoding, errors)
# Old V7 tar format represents a directory as a regular
# file with a trailing slash.
if obj.type == AREGTYPE and obj.name.endswith("/"):
obj.type = DIRTYPE
# The old GNU sparse format occupies some of the unused
# space in the buffer for up to 4 sparse structures.
# Save the them for later processing in _proc_sparse().
if obj.type == GNUTYPE_SPARSE:
pos = 386
structs = []
for i in range(4):
try:
offset = nti(buf[pos:pos + 12])
numbytes = nti(buf[pos + 12:pos + 24])
except ValueError:
break
structs.append((offset, numbytes))
pos += 24
isextended = bool(buf[482])
origsize = nti(buf[483:495])
obj._sparse_structs = (structs, isextended, origsize)
# Remove redundant slashes from directories.
if obj.isdir():
obj.name = obj.name.rstrip("/")
# Reconstruct a ustar longname.
if prefix and obj.type not in GNU_TYPES:
obj.name = prefix + "/" + obj.name
return obj
@classmethod
def fromtarfile(cls, tarfile):
"""Return the next TarInfo object from TarFile object
tarfile.
"""
buf = tarfile.fileobj.read(BLOCKSIZE)
obj = cls.frombuf(buf, tarfile.encoding, tarfile.errors)
obj.offset = tarfile.fileobj.tell() - BLOCKSIZE
return obj._proc_member(tarfile)
#--------------------------------------------------------------------------
# The following are methods that are called depending on the type of a
# member. The entry point is _proc_member() which can be overridden in a
# subclass to add custom _proc_*() methods. A _proc_*() method MUST
# implement the following
# operations:
# 1. Set self.offset_data to the position where the data blocks begin,
# if there is data that follows.
# 2. Set tarfile.offset to the position where the next member's header will
# begin.
# 3. Return self or another valid TarInfo object.
def _proc_member(self, tarfile):
"""Choose the right processing method depending on
the type and call it.
"""
if self.type in (GNUTYPE_LONGNAME, GNUTYPE_LONGLINK):
return self._proc_gnulong(tarfile)
elif self.type == GNUTYPE_SPARSE:
return self._proc_sparse(tarfile)
elif self.type in (XHDTYPE, XGLTYPE, SOLARIS_XHDTYPE):
return self._proc_pax(tarfile)
else:
return self._proc_builtin(tarfile)
def _proc_builtin(self, tarfile):
"""Process a builtin type or an unknown type which
will be treated as a regular file.
"""
self.offset_data = tarfile.fileobj.tell()
offset = self.offset_data
if self.isreg() or self.type not in SUPPORTED_TYPES:
# Skip the following data blocks.
offset += self._block(self.size)
tarfile.offset = offset
# Patch the TarInfo object with saved global
# header information.
self._apply_pax_info(tarfile.pax_headers, tarfile.encoding, tarfile.errors)
return self
def _proc_gnulong(self, tarfile):
"""Process the blocks that hold a GNU longname
or longlink member.
"""
buf = tarfile.fileobj.read(self._block(self.size))
# Fetch the next header and process it.
try:
next = self.fromtarfile(tarfile)
except HeaderError:
raise SubsequentHeaderError("missing or bad subsequent header")
# Patch the TarInfo object from the next header with
# the longname information.
next.offset = self.offset
if self.type == GNUTYPE_LONGNAME:
next.name = nts(buf, tarfile.encoding, tarfile.errors)
elif self.type == GNUTYPE_LONGLINK:
next.linkname = nts(buf, tarfile.encoding, tarfile.errors)
return next
def _proc_sparse(self, tarfile):
"""Process a GNU sparse header plus extra headers.
"""
# We already collected some sparse structures in frombuf().
structs, isextended, origsize = self._sparse_structs
del self._sparse_structs
# Collect sparse structures from extended header blocks.
while isextended:
buf = tarfile.fileobj.read(BLOCKSIZE)
pos = 0
for i in range(21):
try:
offset = nti(buf[pos:pos + 12])
numbytes = nti(buf[pos + 12:pos + 24])
except ValueError:
break
if offset and numbytes:
structs.append((offset, numbytes))
pos += 24
isextended = bool(buf[504])
self.sparse = structs
self.offset_data = tarfile.fileobj.tell()
tarfile.offset = self.offset_data + self._block(self.size)
self.size = origsize
return self
def _proc_pax(self, tarfile):
"""Process an extended or global header as described in
POSIX.1-2008.
"""
# Read the header information.
buf = tarfile.fileobj.read(self._block(self.size))
# A pax header stores supplemental information for either
# the following file (extended) or all following files
# (global).
if self.type == XGLTYPE:
pax_headers = tarfile.pax_headers
else:
pax_headers = tarfile.pax_headers.copy()
# Check if the pax header contains a hdrcharset field. This tells us
# the encoding of the path, linkpath, uname and gname fields. Normally,
# these fields are UTF-8 encoded but since POSIX.1-2008 tar
# implementations are allowed to store them as raw binary strings if
# the translation to UTF-8 fails.
match = re.search(br"\d+ hdrcharset=([^\n]+)\n", buf)
if match is not None:
pax_headers["hdrcharset"] = match.group(1).decode("utf-8")
# For the time being, we don't care about anything other than "BINARY".
# The only other value that is currently allowed by the standard is
# "ISO-IR 10646 2000 UTF-8" in other words UTF-8.
hdrcharset = pax_headers.get("hdrcharset")
if hdrcharset == "BINARY":
encoding = tarfile.encoding
else:
encoding = "utf-8"
# Parse pax header information. A record looks like that:
# "%d %s=%s\n" % (length, keyword, value). length is the size
# of the complete record including the length field itself and
# the newline. keyword and value are both UTF-8 encoded strings.
regex = re.compile(br"(\d+) ([^=]+)=")
pos = 0
while True:
match = regex.match(buf, pos)
if not match:
break
length, keyword = match.groups()
length = int(length)
value = buf[match.end(2) + 1:match.start(1) + length - 1]
# Normally, we could just use "utf-8" as the encoding and "strict"
# as the error handler, but we better not take the risk. For
# example, GNU tar <= 1.23 is known to store filenames it cannot
# translate to UTF-8 as raw strings (unfortunately without a
# hdrcharset=BINARY header).
# We first try the strict standard encoding, and if that fails we
# fall back on the user's encoding and error handler.
keyword = self._decode_pax_field(keyword, "utf-8", "utf-8",
tarfile.errors)
if keyword in PAX_NAME_FIELDS:
value = self._decode_pax_field(value, encoding, tarfile.encoding,
tarfile.errors)
else:
value = self._decode_pax_field(value, "utf-8", "utf-8",
tarfile.errors)
pax_headers[keyword] = value
pos += length
# Fetch the next header.
try:
next = self.fromtarfile(tarfile)
except HeaderError:
raise SubsequentHeaderError("missing or bad subsequent header")
# Process GNU sparse information.
if "GNU.sparse.map" in pax_headers:
# GNU extended sparse format version 0.1.
self._proc_gnusparse_01(next, pax_headers)
elif "GNU.sparse.size" in pax_headers:
# GNU extended sparse format version 0.0.
self._proc_gnusparse_00(next, pax_headers, buf)
elif pax_headers.get("GNU.sparse.major") == "1" and pax_headers.get("GNU.sparse.minor") == "0":
# GNU extended sparse format version 1.0.
self._proc_gnusparse_10(next, pax_headers, tarfile)
if self.type in (XHDTYPE, SOLARIS_XHDTYPE):
# Patch the TarInfo object with the extended header info.
next._apply_pax_info(pax_headers, tarfile.encoding, tarfile.errors)
next.offset = self.offset
if "size" in pax_headers:
# If the extended header replaces the size field,
# we need to recalculate the offset where the next
# header starts.
offset = next.offset_data
if next.isreg() or next.type not in SUPPORTED_TYPES:
offset += next._block(next.size)
tarfile.offset = offset
return next
def _proc_gnusparse_00(self, next, pax_headers, buf):
"""Process a GNU tar extended sparse header, version 0.0.
"""
offsets = []
for match in re.finditer(br"\d+ GNU.sparse.offset=(\d+)\n", buf):
offsets.append(int(match.group(1)))
numbytes = []
for match in re.finditer(br"\d+ GNU.sparse.numbytes=(\d+)\n", buf):
numbytes.append(int(match.group(1)))
next.sparse = list(zip(offsets, numbytes))
def _proc_gnusparse_01(self, next, pax_headers):
"""Process a GNU tar extended sparse header, version 0.1.
"""
sparse = [int(x) for x in pax_headers["GNU.sparse.map"].split(",")]
next.sparse = list(zip(sparse[::2], sparse[1::2]))
def _proc_gnusparse_10(self, next, pax_headers, tarfile):
"""Process a GNU tar extended sparse header, version 1.0.
"""
fields = None
sparse = []
buf = tarfile.fileobj.read(BLOCKSIZE)
fields, buf = buf.split(b"\n", 1)
fields = int(fields)
while len(sparse) < fields * 2:
if b"\n" not in buf:
buf += tarfile.fileobj.read(BLOCKSIZE)
number, buf = buf.split(b"\n", 1)
sparse.append(int(number))
next.offset_data = tarfile.fileobj.tell()
next.sparse = list(zip(sparse[::2], sparse[1::2]))
def _apply_pax_info(self, pax_headers, encoding, errors):
"""Replace fields with supplemental information from a previous
pax extended or global header.
"""
for keyword, value in pax_headers.items():
if keyword == "GNU.sparse.name":
setattr(self, "path", value)
elif keyword == "GNU.sparse.size":
setattr(self, "size", int(value))
elif keyword == "GNU.sparse.realsize":
setattr(self, "size", int(value))
elif keyword in PAX_FIELDS:
if keyword in PAX_NUMBER_FIELDS:
try:
value = PAX_NUMBER_FIELDS[keyword](value)
except ValueError:
value = 0
if keyword == "path":
value = value.rstrip("/")
setattr(self, keyword, value)
self.pax_headers = pax_headers.copy()
def _decode_pax_field(self, value, encoding, fallback_encoding, fallback_errors):
"""Decode a single field from a pax record.
"""
try:
return value.decode(encoding, "strict")
except UnicodeDecodeError:
return value.decode(fallback_encoding, fallback_errors)
def _block(self, count):
"""Round up a byte count by BLOCKSIZE and return it,
e.g. _block(834) => 1024.
"""
blocks, remainder = divmod(count, BLOCKSIZE)
if remainder:
blocks += 1
return blocks * BLOCKSIZE
def isreg(self):
return self.type in REGULAR_TYPES
def isfile(self):
return self.isreg()
def isdir(self):
return self.type == DIRTYPE
def issym(self):
return self.type == SYMTYPE
def islnk(self):
return self.type == LNKTYPE
def ischr(self):
return self.type == CHRTYPE
def isblk(self):
return self.type == BLKTYPE
def isfifo(self):
return self.type == FIFOTYPE
def issparse(self):
return self.sparse is not None
def isdev(self):
return self.type in (CHRTYPE, BLKTYPE, FIFOTYPE)
# class TarInfo
class TarFile(object):
"""The TarFile Class provides an interface to tar archives.
"""
debug = 0 # May be set from 0 (no msgs) to 3 (all msgs)
dereference = False # If true, add content of linked file to the
# tar file, else the link.
ignore_zeros = False # If true, skips empty or invalid blocks and
# continues processing.
errorlevel = 1 # If 0, fatal errors only appear in debug
# messages (if debug >= 0). If > 0, errors
# are passed to the caller as exceptions.
format = DEFAULT_FORMAT # The format to use when creating an archive.
encoding = ENCODING # Encoding for 8-bit character strings.
errors = None # Error handler for unicode conversion.
tarinfo = TarInfo # The default TarInfo class to use.
fileobject = ExFileObject # The default ExFileObject class to use.
def __init__(self, name=None, mode="r", fileobj=None, format=None,
tarinfo=None, dereference=None, ignore_zeros=None, encoding=None,
errors="surrogateescape", pax_headers=None, debug=None, errorlevel=None):
"""Open an (uncompressed) tar archive `name'. `mode' is either 'r' to
read from an existing archive, 'a' to append data to an existing
file or 'w' to create a new file overwriting an existing one. `mode'
defaults to 'r'.
If `fileobj' is given, it is used for reading or writing data. If it
can be determined, `mode' is overridden by `fileobj's mode.
`fileobj' is not closed, when TarFile is closed.
"""
if len(mode) > 1 or mode not in "raw":
raise ValueError("mode must be 'r', 'a' or 'w'")
self.mode = mode
self._mode = {"r": "rb", "a": "r+b", "w": "wb"}[mode]
if not fileobj:
if self.mode == "a" and not os.path.exists(name):
# Create nonexistent files in append mode.
self.mode = "w"
self._mode = "wb"
fileobj = bltn_open(name, self._mode)
self._extfileobj = False
else:
if name is None and hasattr(fileobj, "name"):
name = fileobj.name
if hasattr(fileobj, "mode"):
self._mode = fileobj.mode
self._extfileobj = True
self.name = os.path.abspath(name) if name else None
self.fileobj = fileobj
# Init attributes.
if format is not None:
self.format = format
if tarinfo is not None:
self.tarinfo = tarinfo
if dereference is not None:
self.dereference = dereference
if ignore_zeros is not None:
self.ignore_zeros = ignore_zeros
if encoding is not None:
self.encoding = encoding
self.errors = errors
if pax_headers is not None and self.format == PAX_FORMAT:
self.pax_headers = pax_headers
else:
self.pax_headers = {}
if debug is not None:
self.debug = debug
if errorlevel is not None:
self.errorlevel = errorlevel
# Init datastructures.
self.closed = False
self.members = [] # list of members as TarInfo objects
self._loaded = False # flag if all members have been read
self.offset = self.fileobj.tell()
# current position in the archive file
self.inodes = {} # dictionary caching the inodes of
# archive members already added
try:
if self.mode == "r":
self.firstmember = None
self.firstmember = self.next()
if self.mode == "a":
# Move to the end of the archive,
# before the first empty block.
while True:
self.fileobj.seek(self.offset)
try:
tarinfo = self.tarinfo.fromtarfile(self)
self.members.append(tarinfo)
except EOFHeaderError:
self.fileobj.seek(self.offset)
break
except HeaderError as e:
raise ReadError(str(e))
if self.mode in "aw":
self._loaded = True
if self.pax_headers:
buf = self.tarinfo.create_pax_global_header(self.pax_headers.copy())
self.fileobj.write(buf)
self.offset += len(buf)
except:
if not self._extfileobj:
self.fileobj.close()
self.closed = True
raise
#--------------------------------------------------------------------------
# Below are the classmethods which act as alternate constructors to the
# TarFile class. The open() method is the only one that is needed for
# public use; it is the "super"-constructor and is able to select an
# adequate "sub"-constructor for a particular compression using the mapping
# from OPEN_METH.
#
# This concept allows one to subclass TarFile without losing the comfort of
# the super-constructor. A sub-constructor is registered and made available
# by adding it to the mapping in OPEN_METH.
@classmethod
def open(cls, name=None, mode="r", fileobj=None, bufsize=RECORDSIZE, **kwargs):
"""Open a tar archive for reading, writing or appending. Return
an appropriate TarFile class.
mode:
'r' or 'r:*' open for reading with transparent compression
'r:' open for reading exclusively uncompressed
'r:gz' open for reading with gzip compression
'r:bz2' open for reading with bzip2 compression
'r:xz' open for reading with lzma compression
'a' or 'a:' open for appending, creating the file if necessary
'w' or 'w:' open for writing without compression
'w:gz' open for writing with gzip compression
'w:bz2' open for writing with bzip2 compression
'w:xz' open for writing with lzma compression
'r|*' open a stream of tar blocks with transparent compression
'r|' open an uncompressed stream of tar blocks for reading
'r|gz' open a gzip compressed stream of tar blocks
'r|bz2' open a bzip2 compressed stream of tar blocks
'r|xz' open an lzma compressed stream of tar blocks
'w|' open an uncompressed stream for writing
'w|gz' open a gzip compressed stream for writing
'w|bz2' open a bzip2 compressed stream for writing
'w|xz' open an lzma compressed stream for writing
"""
if not name and not fileobj:
raise ValueError("nothing to open")
if mode in ("r", "r:*"):
# Find out which *open() is appropriate for opening the file.
for comptype in cls.OPEN_METH:
func = getattr(cls, cls.OPEN_METH[comptype])
if fileobj is not None:
saved_pos = fileobj.tell()
try:
return func(name, "r", fileobj, **kwargs)
except (ReadError, CompressionError) as e:
if fileobj is not None:
fileobj.seek(saved_pos)
continue
raise ReadError("file could not be opened successfully")
elif ":" in mode:
filemode, comptype = mode.split(":", 1)
filemode = filemode or "r"
comptype = comptype or "tar"
# Select the *open() function according to
# given compression.
if comptype in cls.OPEN_METH:
func = getattr(cls, cls.OPEN_METH[comptype])
else:
raise CompressionError("unknown compression type %r" % comptype)
return func(name, filemode, fileobj, **kwargs)
elif "|" in mode:
filemode, comptype = mode.split("|", 1)
filemode = filemode or "r"
comptype = comptype or "tar"
if filemode not in "rw":
raise ValueError("mode must be 'r' or 'w'")
stream = _Stream(name, filemode, comptype, fileobj, bufsize)
try:
t = cls(name, filemode, stream, **kwargs)
except:
stream.close()
raise
t._extfileobj = False
return t
elif mode in "aw":
return cls.taropen(name, mode, fileobj, **kwargs)
raise ValueError("undiscernible mode")
@classmethod
def taropen(cls, name, mode="r", fileobj=None, **kwargs):
"""Open uncompressed tar archive name for reading or writing.
"""
if len(mode) > 1 or mode not in "raw":
raise ValueError("mode must be 'r', 'a' or 'w'")
return cls(name, mode, fileobj, **kwargs)
@classmethod
def gzopen(cls, name, mode="r", fileobj=None, compresslevel=9, **kwargs):
"""Open gzip compressed tar archive name for reading or writing.
Appending is not allowed.
"""
if len(mode) > 1 or mode not in "rw":
raise ValueError("mode must be 'r' or 'w'")
try:
import gzip
gzip.GzipFile
except (ImportError, AttributeError):
raise CompressionError("gzip module is not available")
extfileobj = fileobj is not None
try:
fileobj = gzip.GzipFile(name, mode + "b", compresslevel, fileobj)
t = cls.taropen(name, mode, fileobj, **kwargs)
except IOError:
if not extfileobj and fileobj is not None:
fileobj.close()
if fileobj is None:
raise
raise ReadError("not a gzip file")
except:
if not extfileobj and fileobj is not None:
fileobj.close()
raise
t._extfileobj = extfileobj
return t
@classmethod
def bz2open(cls, name, mode="r", fileobj=None, compresslevel=9, **kwargs):
"""Open bzip2 compressed tar archive name for reading or writing.
Appending is not allowed.
"""
if len(mode) > 1 or mode not in "rw":
raise ValueError("mode must be 'r' or 'w'.")
try:
import bz2
except ImportError:
raise CompressionError("bz2 module is not available")
fileobj = bz2.BZ2File(filename=name if fileobj is None else None,
mode=mode, fileobj=fileobj, compresslevel=compresslevel)
try:
t = cls.taropen(name, mode, fileobj, **kwargs)
except (IOError, EOFError):
fileobj.close()
raise ReadError("not a bzip2 file")
t._extfileobj = False
return t
@classmethod
def xzopen(cls, name, mode="r", fileobj=None, preset=None, **kwargs):
"""Open lzma compressed tar archive name for reading or writing.
Appending is not allowed.
"""
if mode not in ("r", "w"):
raise ValueError("mode must be 'r' or 'w'")
try:
import lzma
except ImportError:
raise CompressionError("lzma module is not available")
fileobj = lzma.LZMAFile(filename=name if fileobj is None else None,
mode=mode, fileobj=fileobj, preset=preset)
try:
t = cls.taropen(name, mode, fileobj, **kwargs)
except (lzma.LZMAError, EOFError):
fileobj.close()
raise ReadError("not an lzma file")
t._extfileobj = False
return t
# All *open() methods are registered here.
OPEN_METH = {
"tar": "taropen", # uncompressed tar
"gz": "gzopen", # gzip compressed tar
"bz2": "bz2open", # bzip2 compressed tar
"xz": "xzopen" # lzma compressed tar
}
#--------------------------------------------------------------------------
# The public methods which TarFile provides:
def close(self):
"""Close the TarFile. In write-mode, two finishing zero blocks are
appended to the archive.
"""
if self.closed:
return
if self.mode in "aw":
self.fileobj.write(NUL * (BLOCKSIZE * 2))
self.offset += (BLOCKSIZE * 2)
# fill up the end with zero-blocks
# (like option -b20 for tar does)
blocks, remainder = divmod(self.offset, RECORDSIZE)
if remainder > 0:
self.fileobj.write(NUL * (RECORDSIZE - remainder))
if not self._extfileobj:
self.fileobj.close()
self.closed = True
def getmember(self, name):
"""Return a TarInfo object for member `name'. If `name' can not be
found in the archive, KeyError is raised. If a member occurs more
than once in the archive, its last occurrence is assumed to be the
most up-to-date version.
"""
tarinfo = self._getmember(name)
if tarinfo is None:
raise KeyError("filename %r not found" % name)
return tarinfo
def getmembers(self):
"""Return the members of the archive as a list of TarInfo objects. The
list has the same order as the members in the archive.
"""
self._check()
if not self._loaded: # if we want to obtain a list of
self._load() # all members, we first have to
# scan the whole archive.
return self.members
def getnames(self):
"""Return the members of the archive as a list of their names. It has
the same order as the list returned by getmembers().
"""
return [tarinfo.name for tarinfo in self.getmembers()]
def gettarinfo(self, name=None, arcname=None, fileobj=None):
"""Create a TarInfo object for either the file `name' or the file
object `fileobj' (using os.fstat on its file descriptor). You can
modify some of the TarInfo's attributes before you add it using
addfile(). If given, `arcname' specifies an alternative name for the
file in the archive.
"""
self._check("aw")
# When fileobj is given, replace name by
# fileobj's real name.
if fileobj is not None:
name = fileobj.name
# Building the name of the member in the archive.
# Backward slashes are converted to forward slashes,
# Absolute paths are turned to relative paths.
if arcname is None:
arcname = name
drv, arcname = os.path.splitdrive(arcname)
arcname = arcname.replace(os.sep, "/")
arcname = arcname.lstrip("/")
# Now, fill the TarInfo object with
# information specific for the file.
tarinfo = self.tarinfo()
tarinfo.tarfile = self
# Use os.stat or os.lstat, depending on platform
# and if symlinks shall be resolved.
if fileobj is None:
if hasattr(os, "lstat") and not self.dereference:
statres = os.lstat(name)
else:
statres = os.stat(name)
else:
statres = os.fstat(fileobj.fileno())
linkname = ""
stmd = statres.st_mode
if stat.S_ISREG(stmd):
inode = (statres.st_ino, statres.st_dev)
if not self.dereference and statres.st_nlink > 1 and \
inode in self.inodes and arcname != self.inodes[inode]:
# Is it a hardlink to an already
# archived file?
type = LNKTYPE
linkname = self.inodes[inode]
else:
# The inode is added only if its valid.
# For win32 it is always 0.
type = REGTYPE
if inode[0]:
self.inodes[inode] = arcname
elif stat.S_ISDIR(stmd):
type = DIRTYPE
elif stat.S_ISFIFO(stmd):
type = FIFOTYPE
elif stat.S_ISLNK(stmd):
type = SYMTYPE
linkname = os.readlink(name)
elif stat.S_ISCHR(stmd):
type = CHRTYPE
elif stat.S_ISBLK(stmd):
type = BLKTYPE
else:
return None
# Fill the TarInfo object with all
# information we can get.
tarinfo.name = arcname
tarinfo.mode = stmd
tarinfo.uid = statres.st_uid
tarinfo.gid = statres.st_gid
if type == REGTYPE:
tarinfo.size = statres.st_size
else:
tarinfo.size = 0
tarinfo.mtime = statres.st_mtime
tarinfo.type = type
tarinfo.linkname = linkname
if pwd:
try:
tarinfo.uname = pwd.getpwuid(tarinfo.uid)[0]
except KeyError:
pass
if grp:
try:
tarinfo.gname = grp.getgrgid(tarinfo.gid)[0]
except KeyError:
pass
if type in (CHRTYPE, BLKTYPE):
if hasattr(os, "major") and hasattr(os, "minor"):
tarinfo.devmajor = os.major(statres.st_rdev)
tarinfo.devminor = os.minor(statres.st_rdev)
return tarinfo
def list(self, verbose=True):
"""Print a table of contents to sys.stdout. If `verbose' is False, only
the names of the members are printed. If it is True, an `ls -l'-like
output is produced.
"""
self._check()
for tarinfo in self:
if verbose:
print(filemode(tarinfo.mode), end=' ')
print("%s/%s" % (tarinfo.uname or tarinfo.uid,
tarinfo.gname or tarinfo.gid), end=' ')
if tarinfo.ischr() or tarinfo.isblk():
print("%10s" % ("%d,%d" \
% (tarinfo.devmajor, tarinfo.devminor)), end=' ')
else:
print("%10d" % tarinfo.size, end=' ')
print("%d-%02d-%02d %02d:%02d:%02d" \
% time.localtime(tarinfo.mtime)[:6], end=' ')
print(tarinfo.name + ("/" if tarinfo.isdir() else ""), end=' ')
if verbose:
if tarinfo.issym():
print("->", tarinfo.linkname, end=' ')
if tarinfo.islnk():
print("link to", tarinfo.linkname, end=' ')
print()
def add(self, name, arcname=None, recursive=True, exclude=None, *, filter=None):
"""Add the file `name' to the archive. `name' may be any type of file
(directory, fifo, symbolic link, etc.). If given, `arcname'
specifies an alternative name for the file in the archive.
Directories are added recursively by default. This can be avoided by
setting `recursive' to False. `exclude' is a function that should
return True for each filename to be excluded. `filter' is a function
that expects a TarInfo object argument and returns the changed
TarInfo object, if it returns None the TarInfo object will be
excluded from the archive.
"""
self._check("aw")
if arcname is None:
arcname = name
# Exclude pathnames.
if exclude is not None:
import warnings
warnings.warn("use the filter argument instead",
DeprecationWarning, 2)
if exclude(name):
self._dbg(2, "tarfile: Excluded %r" % name)
return
# Skip if somebody tries to archive the archive...
if self.name is not None and os.path.abspath(name) == self.name:
self._dbg(2, "tarfile: Skipped %r" % name)
return
self._dbg(1, name)
# Create a TarInfo object from the file.
tarinfo = self.gettarinfo(name, arcname)
if tarinfo is None:
self._dbg(1, "tarfile: Unsupported type %r" % name)
return
# Change or exclude the TarInfo object.
if filter is not None:
tarinfo = filter(tarinfo)
if tarinfo is None:
self._dbg(2, "tarfile: Excluded %r" % name)
return
# Append the tar header and data to the archive.
if tarinfo.isreg():
f = bltn_open(name, "rb")
self.addfile(tarinfo, f)
f.close()
elif tarinfo.isdir():
self.addfile(tarinfo)
if recursive:
for f in os.listdir(name):
self.add(os.path.join(name, f), os.path.join(arcname, f),
recursive, exclude, filter=filter)
else:
self.addfile(tarinfo)
def addfile(self, tarinfo, fileobj=None):
"""Add the TarInfo object `tarinfo' to the archive. If `fileobj' is
given, tarinfo.size bytes are read from it and added to the archive.
You can create TarInfo objects using gettarinfo().
On Windows platforms, `fileobj' should always be opened with mode
'rb' to avoid irritation about the file size.
"""
self._check("aw")
tarinfo = copy.copy(tarinfo)
buf = tarinfo.tobuf(self.format, self.encoding, self.errors)
self.fileobj.write(buf)
self.offset += len(buf)
# If there's data to follow, append it.
if fileobj is not None:
copyfileobj(fileobj, self.fileobj, tarinfo.size)
blocks, remainder = divmod(tarinfo.size, BLOCKSIZE)
if remainder > 0:
self.fileobj.write(NUL * (BLOCKSIZE - remainder))
blocks += 1
self.offset += blocks * BLOCKSIZE
self.members.append(tarinfo)
def extractall(self, path=".", members=None):
"""Extract all members from the archive to the current working
directory and set owner, modification time and permissions on
directories afterwards. `path' specifies a different directory
to extract to. `members' is optional and must be a subset of the
list returned by getmembers().
"""
directories = []
if members is None:
members = self
for tarinfo in members:
if tarinfo.isdir():
# Extract directories with a safe mode.
directories.append(tarinfo)
tarinfo = copy.copy(tarinfo)
tarinfo.mode = 0o700
# Do not set_attrs directories, as we will do that further down
self.extract(tarinfo, path, set_attrs=not tarinfo.isdir())
# Reverse sort directories.
directories.sort(key=lambda a: a.name)
directories.reverse()
# Set correct owner, mtime and filemode on directories.
for tarinfo in directories:
dirpath = os.path.join(path, tarinfo.name)
try:
self.chown(tarinfo, dirpath)
self.utime(tarinfo, dirpath)
self.chmod(tarinfo, dirpath)
except ExtractError as e:
if self.errorlevel > 1:
raise
else:
self._dbg(1, "tarfile: %s" % e)
def extract(self, member, path="", set_attrs=True):
"""Extract a member from the archive to the current working directory,
using its full name. Its file information is extracted as accurately
as possible. `member' may be a filename or a TarInfo object. You can
specify a different directory using `path'. File attributes (owner,
mtime, mode) are set unless `set_attrs' is False.
"""
self._check("r")
if isinstance(member, str):
tarinfo = self.getmember(member)
else:
tarinfo = member
# Prepare the link target for makelink().
if tarinfo.islnk():
tarinfo._link_target = os.path.join(path, tarinfo.linkname)
try:
self._extract_member(tarinfo, os.path.join(path, tarinfo.name),
set_attrs=set_attrs)
except EnvironmentError as e:
if self.errorlevel > 0:
raise
else:
if e.filename is None:
self._dbg(1, "tarfile: %s" % e.strerror)
else:
self._dbg(1, "tarfile: %s %r" % (e.strerror, e.filename))
except ExtractError as e:
if self.errorlevel > 1:
raise
else:
self._dbg(1, "tarfile: %s" % e)
def extractfile(self, member):
"""Extract a member from the archive as a file object. `member' may be
a filename or a TarInfo object. If `member' is a regular file, a
file-like object is returned. If `member' is a link, a file-like
object is constructed from the link's target. If `member' is none of
the above, None is returned.
The file-like object is read-only and provides the following
methods: read(), readline(), readlines(), seek() and tell()
"""
self._check("r")
if isinstance(member, str):
tarinfo = self.getmember(member)
else:
tarinfo = member
if tarinfo.isreg():
return self.fileobject(self, tarinfo)
elif tarinfo.type not in SUPPORTED_TYPES:
# If a member's type is unknown, it is treated as a
# regular file.
return self.fileobject(self, tarinfo)
elif tarinfo.islnk() or tarinfo.issym():
if isinstance(self.fileobj, _Stream):
# A small but ugly workaround for the case that someone tries
# to extract a (sym)link as a file-object from a non-seekable
# stream of tar blocks.
raise StreamError("cannot extract (sym)link as file object")
else:
# A (sym)link's file object is its target's file object.
return self.extractfile(self._find_link_target(tarinfo))
else:
# If there's no data associated with the member (directory, chrdev,
# blkdev, etc.), return None instead of a file object.
return None
def _extract_member(self, tarinfo, targetpath, set_attrs=True):
"""Extract the TarInfo object tarinfo to a physical
file called targetpath.
"""
# Fetch the TarInfo object for the given name
# and build the destination pathname, replacing
# forward slashes to platform specific separators.
targetpath = targetpath.rstrip("/")
targetpath = targetpath.replace("/", os.sep)
# Create all upper directories.
upperdirs = os.path.dirname(targetpath)
if upperdirs and not os.path.exists(upperdirs):
# Create directories that are not part of the archive with
# default permissions.
os.makedirs(upperdirs)
if tarinfo.islnk() or tarinfo.issym():
self._dbg(1, "%s -> %s" % (tarinfo.name, tarinfo.linkname))
else:
self._dbg(1, tarinfo.name)
if tarinfo.isreg():
self.makefile(tarinfo, targetpath)
elif tarinfo.isdir():
self.makedir(tarinfo, targetpath)
elif tarinfo.isfifo():
self.makefifo(tarinfo, targetpath)
elif tarinfo.ischr() or tarinfo.isblk():
self.makedev(tarinfo, targetpath)
elif tarinfo.islnk() or tarinfo.issym():
self.makelink(tarinfo, targetpath)
elif tarinfo.type not in SUPPORTED_TYPES:
self.makeunknown(tarinfo, targetpath)
else:
self.makefile(tarinfo, targetpath)
if set_attrs:
self.chown(tarinfo, targetpath)
if not tarinfo.issym():
self.chmod(tarinfo, targetpath)
self.utime(tarinfo, targetpath)
#--------------------------------------------------------------------------
# Below are the different file methods. They are called via
# _extract_member() when extract() is called. They can be replaced in a
# subclass to implement other functionality.
def makedir(self, tarinfo, targetpath):
"""Make a directory called targetpath.
"""
try:
# Use a safe mode for the directory, the real mode is set
# later in _extract_member().
os.mkdir(targetpath, 0o700)
except FileExistsError:
pass
def makefile(self, tarinfo, targetpath):
"""Make a file called targetpath.
"""
source = self.fileobj
source.seek(tarinfo.offset_data)
target = bltn_open(targetpath, "wb")
if tarinfo.sparse is not None:
for offset, size in tarinfo.sparse:
target.seek(offset)
copyfileobj(source, target, size)
else:
copyfileobj(source, target, tarinfo.size)
target.seek(tarinfo.size)
target.truncate()
target.close()
def makeunknown(self, tarinfo, targetpath):
"""Make a file from a TarInfo object with an unknown type
at targetpath.
"""
self.makefile(tarinfo, targetpath)
self._dbg(1, "tarfile: Unknown file type %r, " \
"extracted as regular file." % tarinfo.type)
def makefifo(self, tarinfo, targetpath):
"""Make a fifo called targetpath.
"""
if hasattr(os, "mkfifo"):
os.mkfifo(targetpath)
else:
raise ExtractError("fifo not supported by system")
def makedev(self, tarinfo, targetpath):
"""Make a character or block device called targetpath.
"""
if not hasattr(os, "mknod") or not hasattr(os, "makedev"):
raise ExtractError("special devices not supported by system")
mode = tarinfo.mode
if tarinfo.isblk():
mode |= stat.S_IFBLK
else:
mode |= stat.S_IFCHR
os.mknod(targetpath, mode,
os.makedev(tarinfo.devmajor, tarinfo.devminor))
def makelink(self, tarinfo, targetpath):
"""Make a (symbolic) link called targetpath. If it cannot be created
(platform limitation), we try to make a copy of the referenced file
instead of a link.
"""
try:
# For systems that support symbolic and hard links.
if tarinfo.issym():
os.symlink(tarinfo.linkname, targetpath)
else:
# See extract().
if os.path.exists(tarinfo._link_target):
os.link(tarinfo._link_target, targetpath)
else:
self._extract_member(self._find_link_target(tarinfo),
targetpath)
except symlink_exception:
try:
self._extract_member(self._find_link_target(tarinfo),
targetpath)
except KeyError:
raise ExtractError("unable to resolve link inside archive")
def chown(self, tarinfo, targetpath):
"""Set owner of targetpath according to tarinfo.
"""
if pwd and hasattr(os, "geteuid") and os.geteuid() == 0:
# We have to be root to do so.
try:
g = grp.getgrnam(tarinfo.gname)[2]
except KeyError:
g = tarinfo.gid
try:
u = pwd.getpwnam(tarinfo.uname)[2]
except KeyError:
u = tarinfo.uid
try:
if tarinfo.issym() and hasattr(os, "lchown"):
os.lchown(targetpath, u, g)
else:
if sys.platform != "os2emx":
os.chown(targetpath, u, g)
except EnvironmentError as e:
raise ExtractError("could not change owner")
def chmod(self, tarinfo, targetpath):
"""Set file permissions of targetpath according to tarinfo.
"""
if hasattr(os, 'chmod'):
try:
os.chmod(targetpath, tarinfo.mode)
except EnvironmentError as e:
raise ExtractError("could not change mode")
def utime(self, tarinfo, targetpath):
"""Set modification time of targetpath according to tarinfo.
"""
if not hasattr(os, 'utime'):
return
try:
os.utime(targetpath, (tarinfo.mtime, tarinfo.mtime))
except EnvironmentError as e:
raise ExtractError("could not change modification time")
#--------------------------------------------------------------------------
def next(self):
"""Return the next member of the archive as a TarInfo object, when
TarFile is opened for reading. Return None if there is no more
available.
"""
self._check("ra")
if self.firstmember is not None:
m = self.firstmember
self.firstmember = None
return m
# Read the next block.
self.fileobj.seek(self.offset)
tarinfo = None
while True:
try:
tarinfo = self.tarinfo.fromtarfile(self)
except EOFHeaderError as e:
if self.ignore_zeros:
self._dbg(2, "0x%X: %s" % (self.offset, e))
self.offset += BLOCKSIZE
continue
except InvalidHeaderError as e:
if self.ignore_zeros:
self._dbg(2, "0x%X: %s" % (self.offset, e))
self.offset += BLOCKSIZE
continue
elif self.offset == 0:
raise ReadError(str(e))
except EmptyHeaderError:
if self.offset == 0:
raise ReadError("empty file")
except TruncatedHeaderError as e:
if self.offset == 0:
raise ReadError(str(e))
except SubsequentHeaderError as e:
raise ReadError(str(e))
break
if tarinfo is not None:
self.members.append(tarinfo)
else:
self._loaded = True
return tarinfo
#--------------------------------------------------------------------------
# Little helper methods:
def _getmember(self, name, tarinfo=None, normalize=False):
"""Find an archive member by name from bottom to top.
If tarinfo is given, it is used as the starting point.
"""
# Ensure that all members have been loaded.
members = self.getmembers()
# Limit the member search list up to tarinfo.
if tarinfo is not None:
members = members[:members.index(tarinfo)]
if normalize:
name = os.path.normpath(name)
for member in reversed(members):
if normalize:
member_name = os.path.normpath(member.name)
else:
member_name = member.name
if name == member_name:
return member
def _load(self):
"""Read through the entire archive file and look for readable
members.
"""
while True:
tarinfo = self.next()
if tarinfo is None:
break
self._loaded = True
def _check(self, mode=None):
"""Check if TarFile is still open, and if the operation's mode
corresponds to TarFile's mode.
"""
if self.closed:
raise IOError("%s is closed" % self.__class__.__name__)
if mode is not None and self.mode not in mode:
raise IOError("bad operation for mode %r" % self.mode)
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = os.path.dirname(tarinfo.name) + "/" + tarinfo.linkname
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def __iter__(self):
"""Provide an iterator object.
"""
if self._loaded:
return iter(self.members)
else:
return TarIter(self)
def _dbg(self, level, msg):
"""Write debugging output to sys.stderr.
"""
if level <= self.debug:
print(msg, file=sys.stderr)
def __enter__(self):
self._check()
return self
def __exit__(self, type, value, traceback):
if type is None:
self.close()
else:
# An exception occurred. We must not call close() because
# it would try to write end-of-archive blocks and padding.
if not self._extfileobj:
self.fileobj.close()
self.closed = True
# class TarFile
class TarIter:
"""Iterator Class.
for tarinfo in TarFile(...):
suite...
"""
def __init__(self, tarfile):
"""Construct a TarIter object.
"""
self.tarfile = tarfile
self.index = 0
def __iter__(self):
"""Return iterator object.
"""
return self
def __next__(self):
"""Return the next item using TarFile's next() method.
When all members have been read, set TarFile as _loaded.
"""
# Fix for SF #1100429: Under rare circumstances it can
# happen that getmembers() is called during iteration,
# which will cause TarIter to stop prematurely.
if not self.tarfile._loaded:
tarinfo = self.tarfile.next()
if not tarinfo:
self.tarfile._loaded = True
raise StopIteration
else:
try:
tarinfo = self.tarfile.members[self.index]
except IndexError:
raise StopIteration
self.index += 1
return tarinfo
#--------------------
# exported functions
#--------------------
def is_tarfile(name):
"""Return True if name points to a tar archive that we
are able to handle, else return False.
"""
try:
t = open(name)
t.close()
return True
except TarError:
return False
bltn_open = open
open = TarFile.open
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