tarfile.py

python s60 1.4.5版本的源代码

# Portions Copyright (c) 2005 Nokia Corporation 
#!/usr/bin/env python
# -*- coding: iso-8859-1 -*-
#-------------------------------------------------------------------
# tarfile.py
#
# Module for reading and writing .tar and tar.gz files.
#
# Needs at least Python version 2.2.
#
# Please consult the html documentation in this distribution
# for further details on how to use tarfile.
#
#-------------------------------------------------------------------
# Copyright (C) 2002 Lars Gust鋌el <[e-mail]>
# 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.
#


__version__ = "$Revision: 1.2 $"
# $Source: /isource/cvsroot/amaretto-python/python-port-s60/symbian_python/Lib/tarfile.py,v $

version     = "0.6.7"
__author__  = "Lars Gust鋌el ([e-mail])"
__date__    = "$Date: 2004/04/22 12:09:21 $"
__cvsid__   = "$Id: tarfile.py,v 1.2 2004/04/22 12:09:21 kpetrlai Exp $"
__credits__ = "Gustavo Niemeyer, Niels Gust鋌el, Richard Townsend"

#---------
# Imports
#---------
import sys
import os
import shutil
import stat
import errno
import time
import struct

try:
    import grp, pwd
except ImportError:
    grp = pwd = None

# We won't need this anymore in Python 2.3
#
# We import the _tarfile extension, that contains
# some useful functions to handle devices and symlinks.
# We inject them into os module, as if we were under 2.3.
#
try:
    import _tarfile
    if _tarfile.mknod is None:
        _tarfile = None
except ImportError:
    _tarfile = None
if _tarfile and not hasattr(os, "mknod"):
    os.mknod = _tarfile.mknod
if _tarfile and not hasattr(os, "major"):
    os.major = _tarfile.major
if _tarfile and not hasattr(os, "minor"):
    os.minor = _tarfile.minor
if _tarfile and not hasattr(os, "makedev"):
    os.makedev = _tarfile.makedev
if _tarfile and not hasattr(os, "lchown"):
    os.lchown = _tarfile.lchown

# XXX remove for release (2.3)
try:
    True
    False
except NameError:
    True  = 1
    False = 0

# from tarfile import *
__all__ = ["TarFile", "TarInfo", "is_tarfile", "TarError"]

#---------------------------------------------------------
# tar constants
#---------------------------------------------------------
NUL        = "\0"               # the null character
BLOCKSIZE  = 512                # length of processing blocks
RECORDSIZE = BLOCKSIZE * 20     # length of records
MAGIC      = "ustar"            # magic tar string
VERSION    = "00"               # version number

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
MAXSIZE_MEMBER = 077777777777L  # maximum size of a file (11 octal digits)

REGTYPE  = "0"                  # regular file
AREGTYPE = "\0"                 # regular file
LNKTYPE  = "1"                  # link (inside tarfile)
SYMTYPE  = "2"                  # symbolic link
CHRTYPE  = "3"                  # character special device
BLKTYPE  = "4"                  # block special device
DIRTYPE  = "5"                  # directory
FIFOTYPE = "6"                  # fifo special device
CONTTYPE = "7"                  # contiguous file

GNUTYPE_LONGNAME = "L"          # GNU tar extension for longnames
GNUTYPE_LONGLINK = "K"          # GNU tar extension for longlink
GNUTYPE_SPARSE   = "S"          # GNU tar extension for sparse file

#---------------------------------------------------------
# tarfile constants
#---------------------------------------------------------
SUPPORTED_TYPES = (REGTYPE, AREGTYPE, LNKTYPE,  # file types that tarfile
                   SYMTYPE, DIRTYPE, FIFOTYPE,  # can cope with.
                   CONTTYPE, CHRTYPE, BLKTYPE,
                   GNUTYPE_LONGNAME, GNUTYPE_LONGLINK,
                   GNUTYPE_SPARSE)

REGULAR_TYPES = (REGTYPE, AREGTYPE,             # file types that somehow
                 CONTTYPE, GNUTYPE_SPARSE)      # represent regular files

#---------------------------------------------------------
# Bits used in the mode field, values in octal.
#---------------------------------------------------------
S_IFLNK = 0120000        # symbolic link
S_IFREG = 0100000        # regular file
S_IFBLK = 0060000        # block device
S_IFDIR = 0040000        # directory
S_IFCHR = 0020000        # character device
S_IFIFO = 0010000        # fifo

TSUID   = 04000          # set UID on execution
TSGID   = 02000          # set GID on execution
TSVTX   = 01000          # reserved

TUREAD  = 0400           # read by owner
TUWRITE = 0200           # write by owner
TUEXEC  = 0100           # execute/search by owner
TGREAD  = 0040           # read by group
TGWRITE = 0020           # write by group
TGEXEC  = 0010           # execute/search by group
TOREAD  = 0004           # read by other
TOWRITE = 0002           # write by other
TOEXEC  = 0001           # execute/search by other

#---------------------------------------------------------
# Some useful functions
#---------------------------------------------------------
def nts(s):
    
    return s.split(NUL, 1)[0]

def calc_chksum(buf):
    
    chk = 256                           # chksum field is treated as blanks,
                                        # so the initial value is 8 * ord(" ")
    for c in buf[:148]: chk += ord(c)   # sum up all bytes before chksum
    for c in buf[156:]: chk += ord(c)   # sum up all bytes after chksum
    return chk

def copyfileobj(src, dst, length=None):
    
    if length == 0:
        return
    if length is None:
        shutil.copyfileobj(src, dst)
        return

    BUFSIZE = 16 * 1024
    blocks, remainder = divmod(length, BUFSIZE)
    for b in xrange(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,  "x", TSUID, "S", TUEXEC|TSUID, "s"),
    (TGREAD,  "r"),
    (TGWRITE, "w"),
    (TGEXEC,  "x", TSGID, "S", TGEXEC|TSGID, "s"),
    (TOREAD,  "r"),
    (TOWRITE, "w"),
    (TOEXEC,  "x", TSVTX, "T", TOEXEC|TSVTX, "t"))

def filemode(mode):
    
    s = ""
    for t in filemode_table:
        while True:
            if mode & t[0] == t[0]:
                s += t[1]
            elif len(t) > 2:
                t = t[2:]
                continue
            else:
                s += "-"
            break
    return s

if os.sep != "/":
    normpath = lambda path: os.path.normpath(path).replace(os.sep, "/")
else:
    normpath = os.path.normpath

class TarError(Exception):
    
    pass
class ExtractError(TarError):
    
    pass
class ReadError(TarError):
    
    pass
class CompressionError(TarError):
    
    pass
class StreamError(TarError):
    
    pass

#---------------------------
# internal stream interface
#---------------------------
class _LowLevelFile:
    

    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)

    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:
    

    def __init__(self, name, mode, comptype, fileobj, bufsize):
        
        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      = ""
        self.pos      = 0L
        self.closed   = False

        if comptype == "gz":
            try:
                import zlib
            except ImportError:
                raise CompressionError, "zlib module is not available"
            self.zlib = zlib
            self.crc = zlib.crc32("")
            if mode == "r":
                self._init_read_gz()
            else:
                self._init_write_gz()

        if comptype == "bz2":
            try:
                import bz2
            except ImportError:
                raise CompressionError, "bz2 module is not available"
            if mode == "r":
                self.dbuf = ""
                self.cmp = bz2.BZ2Decompressor()
            else:
                self.cmp = bz2.BZ2Compressor()

    def __del__(self):
        if hasattr(self, "closed") and not self.closed:
            self.close()

    def _init_write_gz(self):
        
        self.cmp = self.zlib.compressobj(9, self.zlib.DEFLATED,
                                            -self.zlib.MAX_WBITS,
                                            self.zlib.DEF_MEM_LEVEL,
                                            0)
        timestamp = struct.pack("<L", long(time.time()))
        self.__write("\037\213\010\010%s\002\377" % timestamp)
        if self.name.endswith(".gz"):
            self.name = self.name[:-3]
        self.__write(self.name + NUL)

    def write(self, s):
        
        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):
        
        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):
        
        if self.closed:
            return

        if self.mode == "w" and self.buf:
            if self.comptype != "tar":
                self.buf += self.cmp.flush()
            self.fileobj.write(self.buf)
            self.buf = ""
            if self.comptype == "gz":
                self.fileobj.write(struct.pack("<l", self.crc))
                self.fileobj.write(struct.pack("<L", self.pos))

        if not self._extfileobj:
            self.fileobj.close()

        self.closed = True

    def _init_read_gz(self):
        
        self.cmp = self.zlib.decompressobj(-self.zlib.MAX_WBITS)
        self.dbuf = ""

        # taken from gzip.GzipFile with some alterations
        if self.__read(2) != "\037\213":
            raise ReadError, "not a gzip file"
        if self.__read(1) != "\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 self.pos

    def seek(self, pos=0):
        
        if pos - self.pos >= 0:
            blocks, remainder = divmod(pos - self.pos, self.bufsize)
            for i in xrange(blocks):
                self.read(self.bufsize)
            self.read(remainder)
        else:
            raise StreamError, "seeking backwards is not allowed"
        return self.pos

    def read(self, size=None):
        
        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):
        
        if self.comptype == "tar":
            return self.__read(size)

        c = len(self.dbuf)
        t = [self.dbuf]
        while c < size:
            buf = self.__read(self.bufsize)
            if not buf:
                break
            buf = self.cmp.decompress(buf)
            t.append(buf)
            c += len(buf)
        t = "".join(t)
        self.dbuf = t[size:]
        return t[:size]