patool/patoolib/util.py

509 lines
17 KiB
Python

# -*- coding: utf-8 -*-
# Copyright (C) 2010-2013 Bastian Kleineidam
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""Utility functions."""
from __future__ import print_function
import os
import sys
import shutil
import subprocess
import mimetypes
import tempfile
import traceback
from distutils.spawn import find_executable
# internal MIME database
mimedb = None
def init_mimedb():
"""Initialize the internal MIME database."""
global mimedb
try:
mimedb = mimetypes.MimeTypes(strict=False)
except Exception as msg:
log_error("could not initialize MIME database: %s" % msg)
return
add_mimedb_data(mimedb)
def add_mimedb_data(mimedb):
"""Add missing encodings and mimetypes to MIME database."""
mimedb.encodings_map['.bz2'] = 'bzip2'
mimedb.encodings_map['.lzma'] = 'lzma'
mimedb.encodings_map['.xz'] = 'xz'
mimedb.encodings_map['.lz'] = 'lzip'
mimedb.suffix_map['.tbz2'] = '.tar.bz2'
add_mimetype(mimedb, 'application/x-lzop', '.lzo')
add_mimetype(mimedb, 'application/x-adf', '.adf')
add_mimetype(mimedb, 'application/x-arj', '.arj')
add_mimetype(mimedb, 'application/x-lzma', '.lzma')
add_mimetype(mimedb, 'application/x-xz', '.xz')
add_mimetype(mimedb, 'application/java-archive', '.jar')
add_mimetype(mimedb, 'application/x-rar', '.rar')
add_mimetype(mimedb, 'application/x-7z-compressed', '.7z')
add_mimetype(mimedb, 'application/x-cab', '.cab')
add_mimetype(mimedb, 'application/x-rpm', '.rpm')
add_mimetype(mimedb, 'application/x-debian-package', '.deb')
add_mimetype(mimedb, 'application/x-ace', '.ace')
add_mimetype(mimedb, 'application/x-archive', '.a')
add_mimetype(mimedb, 'application/x-alzip', '.alz')
add_mimetype(mimedb, 'application/x-arc', '.arc')
add_mimetype(mimedb, 'application/x-lrzip', '.lrz')
add_mimetype(mimedb, 'application/x-lha', '.lha')
add_mimetype(mimedb, 'application/x-lzh', '.lzh')
add_mimetype(mimedb, 'application/x-rzip', '.rz')
add_mimetype(mimedb, 'application/x-zoo', '.zoo')
add_mimetype(mimedb, 'application/x-dms', '.dms')
add_mimetype(mimedb, 'application/x-zip-compressed', '.crx')
add_mimetype(mimedb, 'application/x-shar', '.shar')
add_mimetype(mimedb, 'audio/x-ape', '.ape')
add_mimetype(mimedb, 'audio/x-shn', '.shn')
add_mimetype(mimedb, 'audio/flac', '.flac')
add_mimetype(mimedb, 'application/x-chm', '.chm')
def add_mimetype(mimedb, mimetype, extension):
"""Add or replace a mimetype to be used with the given extension."""
# If extension is already a common type, strict=True must be used.
strict = extension in mimedb.types_map[True]
mimedb.add_type(mimetype, extension, strict=strict)
class PatoolError (Exception):
"""Raised when errors occur."""
pass
class memoized (object):
"""Decorator that caches a function's return value each time it is called.
If called later with the same arguments, the cached value is returned, and
not re-evaluated."""
def __init__(self, func):
"""Set func and init cache."""
self.func = func
self.cache = {}
def __call__(self, *args):
"""Try to find result for function arguments in local cache or
execute the function and fill the cache with the result."""
try:
return self.cache[args]
except KeyError:
self.cache[args] = value = self.func(*args)
return value
except TypeError:
# uncachable -- for instance, passing a list as an argument.
# Better to not cache than to blow up entirely.
return self.func(*args)
def __repr__(self):
"""Return the function's docstring."""
return self.func.__doc__
def backtick (cmd, encoding='utf-8'):
"""Return decoded output from command."""
data = subprocess.Popen(cmd, stdout=subprocess.PIPE).communicate()[0]
return data.decode(encoding)
def run (cmd, **kwargs):
"""Run command without error checking.
@return: command return code"""
# Note that shell_quote_nt() result is not suitable for copy-paste
# (especially on Unix systems), but it looks nicer than shell_quote().
log_info("running %s" % " ".join(map(shell_quote_nt, cmd)))
if kwargs:
log_info(" with %s" % ", ".join("%s=%s" % (k, shell_quote(str(v)))\
for k, v in kwargs.items()))
if kwargs.get("shell"):
# for shell calls the command must be a string
cmd = " ".join(cmd)
return subprocess.call(cmd, **kwargs)
def run_checked (cmd, **kwargs):
"""Run command and raise PatoolError on error."""
retcode = run(cmd, **kwargs)
if retcode:
msg = "Command `%s' returned non-zero exit status %d" % (cmd, retcode)
raise PatoolError(msg)
return retcode
@memoized
def guess_mime (filename):
"""Guess the MIME type of given filename using file(1) and if that
fails by looking at the filename extension with the Python mimetypes
module.
The result of this function is cached.
"""
mime, encoding = guess_mime_file(filename)
if mime is None:
mime, encoding = guess_mime_mimedb(filename)
assert mime is not None or encoding is None
return mime, encoding
Encoding2Mime = {
'gzip': "application/x-gzip",
'bzip2': "application/x-bzip2",
'compress': "application/x-compress",
'lzma': "application/x-lzma",
'lzip': "application/x-lzip",
'xz': "application/x-xz",
}
Mime2Encoding = dict([(_val, _key) for _key, _val in Encoding2Mime.items()])
def guess_mime_mimedb (filename):
"""Guess MIME type from given filename.
@return: tuple (mime, encoding)
"""
mime, encoding = None, None
if mimedb is not None:
mime, encoding = mimedb.guess_type(filename, strict=False)
from . import ArchiveMimetypes, ArchiveCompressions
if mime not in ArchiveMimetypes and encoding in ArchiveCompressions:
# Files like 't.txt.gz' are recognized with encoding as format, and
# an unsupported mime-type like 'text/plain'. Fix this.
mime = Encoding2Mime[encoding]
encoding = None
return mime, encoding
def guess_mime_file (filename):
"""Determine MIME type of filename with file(1):
(a) using `file --mime`
(b) using `file` and look the result string
@return: tuple (mime, encoding)
"""
mime, encoding = None, None
base, ext = os.path.splitext(filename)
if ext.lower() in ('.lzma', '.alz', '.lrz'):
# let mimedb recognize these extensions
return mime, encoding
if os.path.isfile(filename):
file_prog = find_program("file")
if file_prog:
mime, encoding = guess_mime_file_mime(file_prog, filename)
if mime is None:
mime = guess_mime_file_text(file_prog, filename)
return mime, encoding
def guess_mime_file_mime (file_prog, filename):
"""Determine MIME type of filename with file(1) and --mime option.
@return: tuple (mime, encoding)
"""
mime, encoding = None, None
cmd = [file_prog, "--brief", "--mime-type", filename]
try:
mime = backtick(cmd).strip()
except OSError:
# ignore errors, as file(1) is only a fallback
return mime, encoding
from . import ArchiveMimetypes
if mime in Mime2Encoding:
# try to look inside compressed archives
cmd = [file_prog, "--brief", "--mime", "--uncompress", filename]
try:
outparts = backtick(cmd).strip().split(";")
except OSError:
# ignore errors, as file(1) is only a fallback
return mime, encoding
mime2 = outparts[0].split(" ", 1)[0]
if mime2 == 'application/x-empty':
# The uncompressor program file(1) uses is not installed.
# Try to get mime information from the file extension.
mime2, encoding2 = guess_mime_mimedb(filename)
if mime2 in ArchiveMimetypes:
mime = mime2
encoding = encoding2
elif mime2 in ArchiveMimetypes:
mime = mime2
encoding = get_file_mime_encoding(outparts)
if mime not in ArchiveMimetypes:
mime, encoding = None, None
return mime, encoding
def get_file_mime_encoding (parts):
"""Get encoding value from splitted output of file --mime --uncompress."""
for part in parts:
for subpart in part.split(" "):
if subpart.startswith("compressed-encoding="):
mime = subpart.split("=")[1].strip()
return Mime2Encoding.get(mime)
return None
# Match file(1) output text to mime types
FileText2Mime = {
"7-zip archive data": "application/x-7z-compressed",
"ACE archive data": "application/x-ace",
"Amiga DOS disk": "application/x-adf",
"ARJ archive data": "application/x-arj",
"bzip2 compressed data": "application/x-bzip2",
"cpio archive": "application/x-cpio",
"ASCII cpio archive": "application/x-cpio",
"Debian binary package": "application/x-debian-package",
"gzip compressed data": "application/x-gzip",
"lzop compressed data": "application/x-lzop",
"Microsoft Cabinet archive data": "application/vnd.ms-cab-compressed",
"RAR archive data": "application/x-rar",
"RPM ": "application/x-redhat-package-manager",
"POSIX tar archive": "application/x-tar",
"xz compressed data": "application/x-xz",
"Zip archive data": "application/zip",
"compress'd data": "application/x-compress",
"lzip compressed data": "application/x-lzip",
"rzip compressed data": "application/x-rzip",
"current ar archive": "application/x-archive",
"LHa ": "application/x-lha",
"ARC archive data": "application/x-arc",
"Zoo archive data": "application/x-zoo",
"DMS archive data": "application/x-dms",
"Monkey's Audio": "audio/x-ape",
"FLAC audio bitstream data": "audio/flac",
"MS Windows HtmlHelp Data": "application/x-chm",
}
def guess_mime_file_text (file_prog, filename):
"""Determine MIME type of filename with file(1)."""
cmd = [file_prog, "--brief", filename]
try:
output = backtick(cmd).strip()
except OSError:
# ignore errors, as file(1) is only a fallback
return None
# match output against known strings
for matcher, mime in FileText2Mime.items():
if output.startswith(matcher):
return mime
return None
def check_existing_filename (filename, onlyfiles=True):
"""Ensure that given filename is a valid, existing file."""
if not os.path.exists(filename):
raise PatoolError("file `%s' was not found" % filename)
if not os.access(filename, os.R_OK):
raise PatoolError("file `%s' is not readable" % filename)
if onlyfiles and not os.path.isfile(filename):
raise PatoolError("`%s' is not a file" % filename)
def check_new_filename (filename):
"""Check that filename does not already exist."""
if os.path.exists(filename):
raise PatoolError("cannot overwrite existing file `%s'" % filename)
def check_archive_filelist (filenames):
"""Check that file list is not empty and contains only existing files."""
if not filenames:
raise PatoolError("cannot create archive with empty filelist")
for filename in filenames:
check_existing_filename(filename, onlyfiles=False)
def set_mode (filename, flags):
"""Set mode flags for given filename if not already set."""
try:
mode = os.lstat(filename).st_mode
except OSError:
# ignore
return
if not (mode & flags):
try:
os.chmod(filename, flags | mode)
except OSError as msg:
log_error("could not set mode flags for `%s': %s" % (filename, msg))
def tmpdir (dir=None):
"""Return a temporary directory for extraction."""
return tempfile.mkdtemp(suffix='', prefix='Unpack_', dir=dir)
def tmpfile (dir=None, prefix="temp", suffix=None):
"""Return a temporary file."""
return tempfile.mkstemp(suffix=suffix, prefix=prefix, dir=dir)[1]
def shell_quote (value):
"""Quote all shell metacharacters in given string value with strong
(ie. single) quotes, handling the single quote especially."""
if os.name == 'nt':
return shell_quote_nt(value)
return "'%s'" % value.replace("'", r"'\''")
def shell_quote_nt (value):
"""Quote argument for Windows system. Modeled after distutils
_nt_quote_args() function."""
if " " in value:
return '"%s"' % value
return value
def stripext (filename):
"""Return the basename without extension of given filename."""
return os.path.splitext(os.path.basename(filename))[0]
def get_single_outfile (directory, archive, extension=""):
"""Get output filename if archive is in a single file format like gzip."""
outfile = os.path.join(directory, stripext(archive))
if os.path.exists(outfile + extension):
# prevent overwriting existing files
i = 1
newfile = "%s%d" % (outfile, i)
while os.path.exists(newfile + extension):
newfile = "%s%d" % (outfile, i)
i += 1
outfile = newfile
return outfile + extension
def log_error (msg, out=sys.stderr):
"""Print error message to stderr (or any other given output)."""
print("patool error:", msg, file=out)
def log_info (msg, out=sys.stdout):
"""Print info message to stdout (or any other given output)."""
print("patool:", msg, file=out)
def log_internal_error (out=sys.stderr):
"""Print internal error message to stderr."""
print("patool: internal error", file=out)
traceback.print_exc()
print("System info:", file=out)
print("Python %s on %s" % (sys.version, sys.platform), file=out)
def p7zip_supports_rar ():
"""Determine if the RAR codec is installed for 7z program."""
if os.name == 'nt':
# Assume RAR support is compiled into the binary.
return True
return os.path.exists('/usr/lib/p7zip/Codecs/Rar29.so')
@memoized
def find_program (program):
"""Look for program in environment PATH variable."""
path = os.environ['PATH']
if os.name == 'nt':
path = append_to_path(path, get_nt_7z_dir())
path = append_to_path(path, get_nt_mac_dir())
return find_executable(program, path=path)
def append_to_path (path, directory):
"""Add a directory to the PATH environment variable, if it is a valid
directory."""
if not os.path.isdir(directory) or directory in path:
return path
if not path.endswith(os.pathsep):
path += os.pathsep
return path + directory
def get_nt_7z_dir ():
"""Return 7-Zip directory from registry, or an empty string."""
# Python 3.x renamed the _winreg module to winreg
try:
import _winreg as winreg
except ImportError:
import winreg
try:
key = winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE, r"SOFTWARE\7-Zip")
try:
return winreg.QueryValueEx(key, "Path")[0]
finally:
winreg.CloseKey(key)
except WindowsError:
return ""
def get_nt_program_dir ():
"""Return the Windows program files directory."""
progvar = "%ProgramFiles%"
return os.path.expandvars(progvar)
def get_nt_mac_dir ():
"""Return Monkey Audio Compressor (MAC) directory, or an empty string."""
return os.path.join(get_nt_program_dir(), "Monkey's Audio")
def strlist_with_or (alist):
"""Return comma separated string, and last entry appended with ' or '."""
if len(alist) > 1:
return "%s or %s" % (", ".join(alist[:-1]), alist[-1])
return ", ".join(alist)
def is_same_file (filename1, filename2):
"""Check if filename1 and filename2 point to the same file object.
There can be false negatives, ie. the result is False, but it is
the same file anyway. Reason is that network filesystems can create
different paths to the same physical file.
"""
if filename1 == filename2:
return True
if os.name == 'posix':
return os.path.samefile(filename1, filename2)
return is_same_filename(filename1, filename2)
def is_same_filename (filename1, filename2):
"""Check if filename1 and filename2 are the same filename."""
return os.path.realpath(filename1) == os.path.realpath(filename2)
def link_or_copy(src, dst, verbose=False):
"""Try to make a hard link from src to dst and if that fails
copy the file. Hard links save some disk space and linking
should fail fast since no copying is involved.
"""
if verbose:
log_info("Copying %s -> %s" % (src, dst))
try:
os.link(src, dst)
except OSError:
shutil.copy(src, dst)
def chdir(directory):
"""Remember and return current directory before calling os.chdir().
If the current directory could not be determined, return None.
"""
try:
olddir = os.getcwd()
except OSError:
olddir = None
os.chdir(directory)
return olddir
init_mimedb()