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2525 lines (2167 loc) · 89 KB
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"""
Read and write ZIP files.
XXX references to utf-8 need further investigation.
"""
import binascii
import importlib.util
import io
import itertools
import os
import posixpath
import shutil
import stat
import struct
import sys
import threading
import time
import contextlib
import pathlib
try:
import zlib # We may need its compression method
crc32 = zlib.crc32
except ImportError:
zlib = None
crc32 = binascii.crc32
try:
import bz2 # We may need its compression method
except ImportError:
bz2 = None
try:
import lzma # We may need its compression method
except ImportError:
lzma = None
__all__ = ["BadZipFile", "BadZipfile", "error",
"ZIP_STORED", "ZIP_DEFLATED", "ZIP_BZIP2", "ZIP_LZMA",
"is_zipfile", "ZipInfo", "ZipFile", "PyZipFile", "LargeZipFile",
"Path"]
class BadZipFile(Exception):
pass
class LargeZipFile(Exception):
"""
Raised when writing a zipfile, the zipfile requires ZIP64 extensions
and those extensions are disabled.
"""
error = BadZipfile = BadZipFile # Pre-3.2 compatibility names
ZIP64_LIMIT = (1 << 31) - 1
ZIP_FILECOUNT_LIMIT = (1 << 16) - 1
ZIP_MAX_COMMENT = (1 << 16) - 1
# constants for Zip file compression methods
ZIP_STORED = 0
ZIP_DEFLATED = 8
ZIP_BZIP2 = 12
ZIP_LZMA = 14
# Other ZIP compression methods not supported
DEFAULT_VERSION = 20
ZIP64_VERSION = 45
BZIP2_VERSION = 46
LZMA_VERSION = 63
# we recognize (but not necessarily support) all features up to that version
MAX_EXTRACT_VERSION = 63
# Below are some formats and associated data for reading/writing headers using
# the struct module. The names and structures of headers/records are those used
# in the PKWARE description of the ZIP file format:
# http://www.pkware.com/documents/casestudies/APPNOTE.TXT
# (URL valid as of January 2008)
# The "end of central directory" structure, magic number, size, and indices
# (section V.I in the format document)
structEndArchive = b"<4s4H2LH"
stringEndArchive = b"PK\005\006"
sizeEndCentDir = struct.calcsize(structEndArchive)
_ECD_SIGNATURE = 0
_ECD_DISK_NUMBER = 1
_ECD_DISK_START = 2
_ECD_ENTRIES_THIS_DISK = 3
_ECD_ENTRIES_TOTAL = 4
_ECD_SIZE = 5
_ECD_OFFSET = 6
_ECD_COMMENT_SIZE = 7
# These last two indices are not part of the structure as defined in the
# spec, but they are used internally by this module as a convenience
_ECD_COMMENT = 8
_ECD_LOCATION = 9
# The "central directory" structure, magic number, size, and indices
# of entries in the structure (section V.F in the format document)
structCentralDir = "<4s4B4HL2L5H2L"
stringCentralDir = b"PK\001\002"
sizeCentralDir = struct.calcsize(structCentralDir)
# indexes of entries in the central directory structure
_CD_SIGNATURE = 0
_CD_CREATE_VERSION = 1
_CD_CREATE_SYSTEM = 2
_CD_EXTRACT_VERSION = 3
_CD_EXTRACT_SYSTEM = 4
_CD_FLAG_BITS = 5
_CD_COMPRESS_TYPE = 6
_CD_TIME = 7
_CD_DATE = 8
_CD_CRC = 9
_CD_COMPRESSED_SIZE = 10
_CD_UNCOMPRESSED_SIZE = 11
_CD_FILENAME_LENGTH = 12
_CD_EXTRA_FIELD_LENGTH = 13
_CD_COMMENT_LENGTH = 14
_CD_DISK_NUMBER_START = 15
_CD_INTERNAL_FILE_ATTRIBUTES = 16
_CD_EXTERNAL_FILE_ATTRIBUTES = 17
_CD_LOCAL_HEADER_OFFSET = 18
# General purpose bit flags
# Zip Appnote: 4.4.4 general purpose bit flag: (2 bytes)
_MASK_ENCRYPTED = 1 << 0
# Bits 1 and 2 have different meanings depending on the compression used.
_MASK_COMPRESS_OPTION_1 = 1 << 1
# _MASK_COMPRESS_OPTION_2 = 1 << 2
# _MASK_USE_DATA_DESCRIPTOR: If set, crc-32, compressed size and uncompressed
# size are zero in the local header and the real values are written in the data
# descriptor immediately following the compressed data.
_MASK_USE_DATA_DESCRIPTOR = 1 << 3
# Bit 4: Reserved for use with compression method 8, for enhanced deflating.
# _MASK_RESERVED_BIT_4 = 1 << 4
_MASK_COMPRESSED_PATCH = 1 << 5
_MASK_STRONG_ENCRYPTION = 1 << 6
# _MASK_UNUSED_BIT_7 = 1 << 7
# _MASK_UNUSED_BIT_8 = 1 << 8
# _MASK_UNUSED_BIT_9 = 1 << 9
# _MASK_UNUSED_BIT_10 = 1 << 10
_MASK_UTF_FILENAME = 1 << 11
# Bit 12: Reserved by PKWARE for enhanced compression.
# _MASK_RESERVED_BIT_12 = 1 << 12
# _MASK_ENCRYPTED_CENTRAL_DIR = 1 << 13
# Bit 14, 15: Reserved by PKWARE
# _MASK_RESERVED_BIT_14 = 1 << 14
# _MASK_RESERVED_BIT_15 = 1 << 15
# The "local file header" structure, magic number, size, and indices
# (section V.A in the format document)
structFileHeader = "<4s2B4HL2L2H"
stringFileHeader = b"PK\003\004"
sizeFileHeader = struct.calcsize(structFileHeader)
_FH_SIGNATURE = 0
_FH_EXTRACT_VERSION = 1
_FH_EXTRACT_SYSTEM = 2
_FH_GENERAL_PURPOSE_FLAG_BITS = 3
_FH_COMPRESSION_METHOD = 4
_FH_LAST_MOD_TIME = 5
_FH_LAST_MOD_DATE = 6
_FH_CRC = 7
_FH_COMPRESSED_SIZE = 8
_FH_UNCOMPRESSED_SIZE = 9
_FH_FILENAME_LENGTH = 10
_FH_EXTRA_FIELD_LENGTH = 11
# The "Zip64 end of central directory locator" structure, magic number, and size
structEndArchive64Locator = "<4sLQL"
stringEndArchive64Locator = b"PK\x06\x07"
sizeEndCentDir64Locator = struct.calcsize(structEndArchive64Locator)
# The "Zip64 end of central directory" record, magic number, size, and indices
# (section V.G in the format document)
structEndArchive64 = "<4sQ2H2L4Q"
stringEndArchive64 = b"PK\x06\x06"
sizeEndCentDir64 = struct.calcsize(structEndArchive64)
_CD64_SIGNATURE = 0
_CD64_DIRECTORY_RECSIZE = 1
_CD64_CREATE_VERSION = 2
_CD64_EXTRACT_VERSION = 3
_CD64_DISK_NUMBER = 4
_CD64_DISK_NUMBER_START = 5
_CD64_NUMBER_ENTRIES_THIS_DISK = 6
_CD64_NUMBER_ENTRIES_TOTAL = 7
_CD64_DIRECTORY_SIZE = 8
_CD64_OFFSET_START_CENTDIR = 9
_DD_SIGNATURE = 0x08074b50
_EXTRA_FIELD_STRUCT = struct.Struct('<HH')
def _strip_extra(extra, xids):
# Remove Extra Fields with specified IDs.
unpack = _EXTRA_FIELD_STRUCT.unpack
modified = False
buffer = []
start = i = 0
while i + 4 <= len(extra):
xid, xlen = unpack(extra[i : i + 4])
j = i + 4 + xlen
if xid in xids:
if i != start:
buffer.append(extra[start : i])
start = j
modified = True
i = j
if not modified:
return extra
return b''.join(buffer)
def _check_zipfile(fp):
try:
if _EndRecData(fp):
return True # file has correct magic number
except OSError:
pass
return False
def is_zipfile(filename):
"""Quickly see if a file is a ZIP file by checking the magic number.
The filename argument may be a file or file-like object too.
"""
result = False
try:
if hasattr(filename, "read"):
result = _check_zipfile(fp=filename)
else:
with open(filename, "rb") as fp:
result = _check_zipfile(fp)
except OSError:
pass
return result
def _EndRecData64(fpin, offset, endrec):
"""
Read the ZIP64 end-of-archive records and use that to update endrec
"""
try:
fpin.seek(offset - sizeEndCentDir64Locator, 2)
except OSError:
# If the seek fails, the file is not large enough to contain a ZIP64
# end-of-archive record, so just return the end record we were given.
return endrec
data = fpin.read(sizeEndCentDir64Locator)
if len(data) != sizeEndCentDir64Locator:
return endrec
sig, diskno, reloff, disks = struct.unpack(structEndArchive64Locator, data)
if sig != stringEndArchive64Locator:
return endrec
if diskno != 0 or disks > 1:
raise BadZipFile("zipfiles that span multiple disks are not supported")
# Assume no 'zip64 extensible data'
fpin.seek(offset - sizeEndCentDir64Locator - sizeEndCentDir64, 2)
data = fpin.read(sizeEndCentDir64)
if len(data) != sizeEndCentDir64:
return endrec
sig, sz, create_version, read_version, disk_num, disk_dir, \
dircount, dircount2, dirsize, diroffset = \
struct.unpack(structEndArchive64, data)
if sig != stringEndArchive64:
return endrec
# Update the original endrec using data from the ZIP64 record
endrec[_ECD_SIGNATURE] = sig
endrec[_ECD_DISK_NUMBER] = disk_num
endrec[_ECD_DISK_START] = disk_dir
endrec[_ECD_ENTRIES_THIS_DISK] = dircount
endrec[_ECD_ENTRIES_TOTAL] = dircount2
endrec[_ECD_SIZE] = dirsize
endrec[_ECD_OFFSET] = diroffset
return endrec
def _EndRecData(fpin):
"""Return data from the "End of Central Directory" record, or None.
The data is a list of the nine items in the ZIP "End of central dir"
record followed by a tenth item, the file seek offset of this record."""
# Determine file size
fpin.seek(0, 2)
filesize = fpin.tell()
# Check to see if this is ZIP file with no archive comment (the
# "end of central directory" structure should be the last item in the
# file if this is the case).
try:
fpin.seek(-sizeEndCentDir, 2)
except OSError:
return None
data = fpin.read()
if (len(data) == sizeEndCentDir and
data[0:4] == stringEndArchive and
data[-2:] == b"\000\000"):
# the signature is correct and there's no comment, unpack structure
endrec = struct.unpack(structEndArchive, data)
endrec=list(endrec)
# Append a blank comment and record start offset
endrec.append(b"")
endrec.append(filesize - sizeEndCentDir)
# Try to read the "Zip64 end of central directory" structure
return _EndRecData64(fpin, -sizeEndCentDir, endrec)
# Either this is not a ZIP file, or it is a ZIP file with an archive
# comment. Search the end of the file for the "end of central directory"
# record signature. The comment is the last item in the ZIP file and may be
# up to 64K long. It is assumed that the "end of central directory" magic
# number does not appear in the comment.
maxCommentStart = max(filesize - (1 << 16) - sizeEndCentDir, 0)
fpin.seek(maxCommentStart, 0)
data = fpin.read()
start = data.rfind(stringEndArchive)
if start >= 0:
# found the magic number; attempt to unpack and interpret
recData = data[start:start+sizeEndCentDir]
if len(recData) != sizeEndCentDir:
# Zip file is corrupted.
return None
endrec = list(struct.unpack(structEndArchive, recData))
commentSize = endrec[_ECD_COMMENT_SIZE] #as claimed by the zip file
comment = data[start+sizeEndCentDir:start+sizeEndCentDir+commentSize]
endrec.append(comment)
endrec.append(maxCommentStart + start)
# Try to read the "Zip64 end of central directory" structure
return _EndRecData64(fpin, maxCommentStart + start - filesize,
endrec)
# Unable to find a valid end of central directory structure
return None
class ZipInfo (object):
"""Class with attributes describing each file in the ZIP archive."""
__slots__ = (
'orig_filename',
'filename',
'date_time',
'compress_type',
'_compresslevel',
'comment',
'extra',
'create_system',
'create_version',
'extract_version',
'reserved',
'flag_bits',
'volume',
'internal_attr',
'external_attr',
'header_offset',
'CRC',
'compress_size',
'file_size',
'_raw_time',
)
def __init__(self, filename="NoName", date_time=(1980,1,1,0,0,0)):
self.orig_filename = filename # Original file name in archive
# Terminate the file name at the first null byte. Null bytes in file
# names are used as tricks by viruses in archives.
null_byte = filename.find(chr(0))
if null_byte >= 0:
filename = filename[0:null_byte]
# This is used to ensure paths in generated ZIP files always use
# forward slashes as the directory separator, as required by the
# ZIP format specification.
if os.sep != "/" and os.sep in filename:
filename = filename.replace(os.sep, "/")
self.filename = filename # Normalized file name
self.date_time = date_time # year, month, day, hour, min, sec
if date_time[0] < 1980:
raise ValueError('ZIP does not support timestamps before 1980')
# Standard values:
self.compress_type = ZIP_STORED # Type of compression for the file
self._compresslevel = None # Level for the compressor
self.comment = b"" # Comment for each file
self.extra = b"" # ZIP extra data
if sys.platform == 'win32':
self.create_system = 0 # System which created ZIP archive
else:
# Assume everything else is unix-y
self.create_system = 3 # System which created ZIP archive
self.create_version = DEFAULT_VERSION # Version which created ZIP archive
self.extract_version = DEFAULT_VERSION # Version needed to extract archive
self.reserved = 0 # Must be zero
self.flag_bits = 0 # ZIP flag bits
self.volume = 0 # Volume number of file header
self.internal_attr = 0 # Internal attributes
self.external_attr = 0 # External file attributes
self.compress_size = 0 # Size of the compressed file
self.file_size = 0 # Size of the uncompressed file
# Other attributes are set by class ZipFile:
# header_offset Byte offset to the file header
# CRC CRC-32 of the uncompressed file
def __repr__(self):
result = ['<%s filename=%r' % (self.__class__.__name__, self.filename)]
if self.compress_type != ZIP_STORED:
result.append(' compress_type=%s' %
compressor_names.get(self.compress_type,
self.compress_type))
hi = self.external_attr >> 16
lo = self.external_attr & 0xFFFF
if hi:
result.append(' filemode=%r' % stat.filemode(hi))
if lo:
result.append(' external_attr=%#x' % lo)
isdir = self.is_dir()
if not isdir or self.file_size:
result.append(' file_size=%r' % self.file_size)
if ((not isdir or self.compress_size) and
(self.compress_type != ZIP_STORED or
self.file_size != self.compress_size)):
result.append(' compress_size=%r' % self.compress_size)
result.append('>')
return ''.join(result)
def FileHeader(self, zip64=None):
"""Return the per-file header as a bytes object."""
dt = self.date_time
dosdate = (dt[0] - 1980) << 9 | dt[1] << 5 | dt[2]
dostime = dt[3] << 11 | dt[4] << 5 | (dt[5] // 2)
if self.flag_bits & _MASK_USE_DATA_DESCRIPTOR:
# Set these to zero because we write them after the file data
CRC = compress_size = file_size = 0
else:
CRC = self.CRC
compress_size = self.compress_size
file_size = self.file_size
extra = self.extra
min_version = 0
if zip64 is None:
zip64 = file_size > ZIP64_LIMIT or compress_size > ZIP64_LIMIT
if zip64:
fmt = '<HHQQ'
extra = extra + struct.pack(fmt,
1, struct.calcsize(fmt)-4, file_size, compress_size)
if file_size > ZIP64_LIMIT or compress_size > ZIP64_LIMIT:
if not zip64:
raise LargeZipFile("Filesize would require ZIP64 extensions")
# File is larger than what fits into a 4 byte integer,
# fall back to the ZIP64 extension
file_size = 0xffffffff
compress_size = 0xffffffff
min_version = ZIP64_VERSION
if self.compress_type == ZIP_BZIP2:
min_version = max(BZIP2_VERSION, min_version)
elif self.compress_type == ZIP_LZMA:
min_version = max(LZMA_VERSION, min_version)
self.extract_version = max(min_version, self.extract_version)
self.create_version = max(min_version, self.create_version)
filename, flag_bits = self._encodeFilenameFlags()
header = struct.pack(structFileHeader, stringFileHeader,
self.extract_version, self.reserved, flag_bits,
self.compress_type, dostime, dosdate, CRC,
compress_size, file_size,
len(filename), len(extra))
return header + filename + extra
def _encodeFilenameFlags(self):
try:
return self.filename.encode('ascii'), self.flag_bits & ~_MASK_UTF_FILENAME
except UnicodeEncodeError:
return self.filename.encode('utf-8'), self.flag_bits | _MASK_UTF_FILENAME
def _decodeExtra(self):
# Try to decode the extra field.
extra = self.extra
unpack = struct.unpack
while len(extra) >= 4:
tp, ln = unpack('<HH', extra[:4])
if ln+4 > len(extra):
raise BadZipFile("Corrupt extra field %04x (size=%d)" % (tp, ln))
if tp == 0x0001:
data = extra[4:ln+4]
# ZIP64 extension (large files and/or large archives)
try:
if self.file_size in (0xFFFF_FFFF_FFFF_FFFF, 0xFFFF_FFFF):
field = "File size"
self.file_size, = unpack('<Q', data[:8])
data = data[8:]
if self.compress_size == 0xFFFF_FFFF:
field = "Compress size"
self.compress_size, = unpack('<Q', data[:8])
data = data[8:]
if self.header_offset == 0xFFFF_FFFF:
field = "Header offset"
self.header_offset, = unpack('<Q', data[:8])
except struct.error:
raise BadZipFile(f"Corrupt zip64 extra field. "
f"{field} not found.") from None
extra = extra[ln+4:]
@classmethod
def from_file(cls, filename, arcname=None, *, strict_timestamps=True):
"""Construct an appropriate ZipInfo for a file on the filesystem.
filename should be the path to a file or directory on the filesystem.
arcname is the name which it will have within the archive (by default,
this will be the same as filename, but without a drive letter and with
leading path separators removed).
"""
if isinstance(filename, os.PathLike):
filename = os.fspath(filename)
st = os.stat(filename)
isdir = stat.S_ISDIR(st.st_mode)
mtime = time.localtime(st.st_mtime)
date_time = mtime[0:6]
if not strict_timestamps and date_time[0] < 1980:
date_time = (1980, 1, 1, 0, 0, 0)
elif not strict_timestamps and date_time[0] > 2107:
date_time = (2107, 12, 31, 23, 59, 59)
# Create ZipInfo instance to store file information
if arcname is None:
arcname = filename
arcname = os.path.normpath(os.path.splitdrive(arcname)[1])
while arcname[0] in (os.sep, os.altsep):
arcname = arcname[1:]
if isdir:
arcname += '/'
zinfo = cls(arcname, date_time)
zinfo.external_attr = (st.st_mode & 0xFFFF) << 16 # Unix attributes
if isdir:
zinfo.file_size = 0
zinfo.external_attr |= 0x10 # MS-DOS directory flag
else:
zinfo.file_size = st.st_size
return zinfo
def is_dir(self):
"""Return True if this archive member is a directory."""
return self.filename[-1] == '/'
# ZIP encryption uses the CRC32 one-byte primitive for scrambling some
# internal keys. We noticed that a direct implementation is faster than
# relying on binascii.crc32().
_crctable = None
def _gen_crc(crc):
for j in range(8):
if crc & 1:
crc = (crc >> 1) ^ 0xEDB88320
else:
crc >>= 1
return crc
# ZIP supports a password-based form of encryption. Even though known
# plaintext attacks have been found against it, it is still useful
# to be able to get data out of such a file.
#
# Usage:
# zd = _ZipDecrypter(mypwd)
# plain_bytes = zd(cypher_bytes)
def _ZipDecrypter(pwd):
key0 = 305419896
key1 = 591751049
key2 = 878082192
global _crctable
if _crctable is None:
_crctable = list(map(_gen_crc, range(256)))
crctable = _crctable
def crc32(ch, crc):
"""Compute the CRC32 primitive on one byte."""
return (crc >> 8) ^ crctable[(crc ^ ch) & 0xFF]
def update_keys(c):
nonlocal key0, key1, key2
key0 = crc32(c, key0)
key1 = (key1 + (key0 & 0xFF)) & 0xFFFFFFFF
key1 = (key1 * 134775813 + 1) & 0xFFFFFFFF
key2 = crc32(key1 >> 24, key2)
for p in pwd:
update_keys(p)
def decrypter(data):
"""Decrypt a bytes object."""
result = bytearray()
append = result.append
for c in data:
k = key2 | 2
c ^= ((k * (k^1)) >> 8) & 0xFF
update_keys(c)
append(c)
return bytes(result)
return decrypter
class LZMACompressor:
def __init__(self):
self._comp = None
def _init(self):
props = lzma._encode_filter_properties({'id': lzma.FILTER_LZMA1})
self._comp = lzma.LZMACompressor(lzma.FORMAT_RAW, filters=[
lzma._decode_filter_properties(lzma.FILTER_LZMA1, props)
])
return struct.pack('<BBH', 9, 4, len(props)) + props
def compress(self, data):
if self._comp is None:
return self._init() + self._comp.compress(data)
return self._comp.compress(data)
def flush(self):
if self._comp is None:
return self._init() + self._comp.flush()
return self._comp.flush()
class LZMADecompressor:
def __init__(self):
self._decomp = None
self._unconsumed = b''
self.eof = False
def decompress(self, data):
if self._decomp is None:
self._unconsumed += data
if len(self._unconsumed) <= 4:
return b''
psize, = struct.unpack('<H', self._unconsumed[2:4])
if len(self._unconsumed) <= 4 + psize:
return b''
self._decomp = lzma.LZMADecompressor(lzma.FORMAT_RAW, filters=[
lzma._decode_filter_properties(lzma.FILTER_LZMA1,
self._unconsumed[4:4 + psize])
])
data = self._unconsumed[4 + psize:]
del self._unconsumed
result = self._decomp.decompress(data)
self.eof = self._decomp.eof
return result
compressor_names = {
0: 'store',
1: 'shrink',
2: 'reduce',
3: 'reduce',
4: 'reduce',
5: 'reduce',
6: 'implode',
7: 'tokenize',
8: 'deflate',
9: 'deflate64',
10: 'implode',
12: 'bzip2',
14: 'lzma',
18: 'terse',
19: 'lz77',
97: 'wavpack',
98: 'ppmd',
}
def _check_compression(compression):
if compression == ZIP_STORED:
pass
elif compression == ZIP_DEFLATED:
if not zlib:
raise RuntimeError(
"Compression requires the (missing) zlib module")
elif compression == ZIP_BZIP2:
if not bz2:
raise RuntimeError(
"Compression requires the (missing) bz2 module")
elif compression == ZIP_LZMA:
if not lzma:
raise RuntimeError(
"Compression requires the (missing) lzma module")
else:
raise NotImplementedError("That compression method is not supported")
def _get_compressor(compress_type, compresslevel=None):
if compress_type == ZIP_DEFLATED:
if compresslevel is not None:
return zlib.compressobj(compresslevel, zlib.DEFLATED, -15)
return zlib.compressobj(zlib.Z_DEFAULT_COMPRESSION, zlib.DEFLATED, -15)
elif compress_type == ZIP_BZIP2:
if compresslevel is not None:
return bz2.BZ2Compressor(compresslevel)
return bz2.BZ2Compressor()
# compresslevel is ignored for ZIP_LZMA
elif compress_type == ZIP_LZMA:
return LZMACompressor()
else:
return None
def _get_decompressor(compress_type):
_check_compression(compress_type)
if compress_type == ZIP_STORED:
return None
elif compress_type == ZIP_DEFLATED:
return zlib.decompressobj(-15)
elif compress_type == ZIP_BZIP2:
return bz2.BZ2Decompressor()
elif compress_type == ZIP_LZMA:
return LZMADecompressor()
else:
descr = compressor_names.get(compress_type)
if descr:
raise NotImplementedError("compression type %d (%s)" % (compress_type, descr))
else:
raise NotImplementedError("compression type %d" % (compress_type,))
class _SharedFile:
def __init__(self, file, pos, close, lock, writing):
self._file = file
self._pos = pos
self._close = close
self._lock = lock
self._writing = writing
self.seekable = file.seekable
def tell(self):
return self._pos
def seek(self, offset, whence=0):
with self._lock:
if self._writing():
raise ValueError("Can't reposition in the ZIP file while "
"there is an open writing handle on it. "
"Close the writing handle before trying to read.")
self._file.seek(offset, whence)
self._pos = self._file.tell()
return self._pos
def read(self, n=-1):
with self._lock:
if self._writing():
raise ValueError("Can't read from the ZIP file while there "
"is an open writing handle on it. "
"Close the writing handle before trying to read.")
self._file.seek(self._pos)
data = self._file.read(n)
self._pos = self._file.tell()
return data
def close(self):
if self._file is not None:
fileobj = self._file
self._file = None
self._close(fileobj)
# Provide the tell method for unseekable stream
class _Tellable:
def __init__(self, fp):
self.fp = fp
self.offset = 0
def write(self, data):
n = self.fp.write(data)
self.offset += n
return n
def tell(self):
return self.offset
def flush(self):
self.fp.flush()
def close(self):
self.fp.close()
class ZipExtFile(io.BufferedIOBase):
"""File-like object for reading an archive member.
Is returned by ZipFile.open().
"""
# Max size supported by decompressor.
MAX_N = 1 << 31 - 1
# Read from compressed files in 4k blocks.
MIN_READ_SIZE = 4096
# Chunk size to read during seek
MAX_SEEK_READ = 1 << 24
def __init__(self, fileobj, mode, zipinfo, pwd=None,
close_fileobj=False):
self._fileobj = fileobj
self._pwd = pwd
self._close_fileobj = close_fileobj
self._compress_type = zipinfo.compress_type
self._compress_left = zipinfo.compress_size
self._left = zipinfo.file_size
self._decompressor = _get_decompressor(self._compress_type)
self._eof = False
self._readbuffer = b''
self._offset = 0
self.newlines = None
self.mode = mode
self.name = zipinfo.filename
if hasattr(zipinfo, 'CRC'):
self._expected_crc = zipinfo.CRC
self._running_crc = crc32(b'')
else:
self._expected_crc = None
self._seekable = False
try:
if fileobj.seekable():
self._orig_compress_start = fileobj.tell()
self._orig_compress_size = zipinfo.compress_size
self._orig_file_size = zipinfo.file_size
self._orig_start_crc = self._running_crc
self._seekable = True
except AttributeError:
pass
self._decrypter = None
if pwd:
if zipinfo.flag_bits & _MASK_USE_DATA_DESCRIPTOR:
# compare against the file type from extended local headers
check_byte = (zipinfo._raw_time >> 8) & 0xff
else:
# compare against the CRC otherwise
check_byte = (zipinfo.CRC >> 24) & 0xff
h = self._init_decrypter()
if h != check_byte:
raise RuntimeError("Bad password for file %r" % zipinfo.orig_filename)
def _init_decrypter(self):
self._decrypter = _ZipDecrypter(self._pwd)
# The first 12 bytes in the cypher stream is an encryption header
# used to strengthen the algorithm. The first 11 bytes are
# completely random, while the 12th contains the MSB of the CRC,
# or the MSB of the file time depending on the header type
# and is used to check the correctness of the password.
header = self._fileobj.read(12)
self._compress_left -= 12
return self._decrypter(header)[11]
def __repr__(self):
result = ['<%s.%s' % (self.__class__.__module__,
self.__class__.__qualname__)]
if not self.closed:
result.append(' name=%r mode=%r' % (self.name, self.mode))
if self._compress_type != ZIP_STORED:
result.append(' compress_type=%s' %
compressor_names.get(self._compress_type,
self._compress_type))
else:
result.append(' [closed]')
result.append('>')
return ''.join(result)
def readline(self, limit=-1):
"""Read and return a line from the stream.
If limit is specified, at most limit bytes will be read.
"""
if limit < 0:
# Shortcut common case - newline found in buffer.
i = self._readbuffer.find(b'\n', self._offset) + 1
if i > 0:
line = self._readbuffer[self._offset: i]
self._offset = i
return line
return io.BufferedIOBase.readline(self, limit)
def peek(self, n=1):
"""Returns buffered bytes without advancing the position."""
if n > len(self._readbuffer) - self._offset:
chunk = self.read(n)
if len(chunk) > self._offset:
self._readbuffer = chunk + self._readbuffer[self._offset:]
self._offset = 0
else:
self._offset -= len(chunk)
# Return up to 512 bytes to reduce allocation overhead for tight loops.
return self._readbuffer[self._offset: self._offset + 512]
def readable(self):
if self.closed:
raise ValueError("I/O operation on closed file.")
return True
def read(self, n=-1):
"""Read and return up to n bytes.
If the argument is omitted, None, or negative, data is read and returned until EOF is reached.
"""
if self.closed:
raise ValueError("read from closed file.")
if n is None or n < 0:
buf = self._readbuffer[self._offset:]
self._readbuffer = b''
self._offset = 0
while not self._eof:
buf += self._read1(self.MAX_N)
return buf
end = n + self._offset
if end < len(self._readbuffer):
buf = self._readbuffer[self._offset:end]
self._offset = end
return buf
n = end - len(self._readbuffer)
buf = self._readbuffer[self._offset:]
self._readbuffer = b''
self._offset = 0
while n > 0 and not self._eof:
data = self._read1(n)
if n < len(data):
self._readbuffer = data
self._offset = n
buf += data[:n]
break
buf += data
n -= len(data)
return buf
def _update_crc(self, newdata):
# Update the CRC using the given data.
if self._expected_crc is None:
# No need to compute the CRC if we don't have a reference value
return
self._running_crc = crc32(newdata, self._running_crc)
# Check the CRC if we're at the end of the file
if self._eof and self._running_crc != self._expected_crc:
raise BadZipFile("Bad CRC-32 for file %r" % self.name)
def read1(self, n):
"""Read up to n bytes with at most one read() system call."""
if n is None or n < 0:
buf = self._readbuffer[self._offset:]
self._readbuffer = b''
self._offset = 0
while not self._eof:
data = self._read1(self.MAX_N)
if data:
buf += data
break
return buf
end = n + self._offset
if end < len(self._readbuffer):
buf = self._readbuffer[self._offset:end]
self._offset = end
return buf
n = end - len(self._readbuffer)
buf = self._readbuffer[self._offset:]
self._readbuffer = b''
self._offset = 0
if n > 0:
while not self._eof:
data = self._read1(n)
if n < len(data):
self._readbuffer = data
self._offset = n