"""Temporary files. This module provides generic, low- and high-level interfaces forcreating temporary files and directories.  The interfaces listedas "safe" just below can be used without fear of race conditions.Those listed as "unsafe" cannot, and are provided for backwardcompatibility only. This module also provides some data items to the user:   TMP_MAX  - maximum number of names that will be tried before             giving up.  template - the default prefix for all temporary names.             You may change this to control the default prefix.  tempdir  - If this is set to a string before the first use of             any routine from this module, it will be considered as             another candidate location to store temporary files.""" __all__ = [    "NamedTemporaryFile", "TemporaryFile", # high level safe interfaces    "mkstemp", "mkdtemp",                  # low level safe interfaces    "mktemp",                              # deprecated unsafe interface    "TMP_MAX", "gettempprefix",            # constants    "tempdir", "gettempdir"   ]  # Imports. import os as _osimport errno as _errnofrom random import Random as _Random if _os.name == 'mac':    import Carbon.Folder as _Folder    import Carbon.Folders as _Folders try:    import fcntl as _fcntlexcept ImportError:    def _set_cloexec(fd):        passelse:    def _set_cloexec(fd):        try:            flags = _fcntl.fcntl(fd, _fcntl.F_GETFD, 0)        except IOError:            pass        else:            # flags read successfully, modify            flags |= _fcntl.FD_CLOEXEC            _fcntl.fcntl(fd, _fcntl.F_SETFD, flags)  try:    import thread as _threadexcept ImportError:    import dummy_thread as _thread_allocate_lock = _thread.allocate_lock _text_openflags = _os.O_RDWR | _os.O_CREAT | _os.O_EXCLif hasattr(_os, 'O_NOINHERIT'):    _text_openflags |= _os.O_NOINHERITif hasattr(_os, 'O_NOFOLLOW'):    _text_openflags |= _os.O_NOFOLLOW _bin_openflags = _text_openflagsif hasattr(_os, 'O_BINARY'):    _bin_openflags |= _os.O_BINARY if hasattr(_os, 'TMP_MAX'):    TMP_MAX = _os.TMP_MAXelse:    TMP_MAX = 10000 template = "tmp" tempdir = None # Internal routines. _once_lock = _allocate_lock() if hasattr(_os, "lstat"):    _stat = _os.lstatelif hasattr(_os, "stat"):    _stat = _os.statelse:    # Fallback.  All we need is something that raises os.error if the    # file doesn't exist.    def _stat(fn):        try:            f = open(fn)        except IOError:            raise _os.error        f.close() def _exists(fn):    try:        _stat(fn)    except _os.error:        return False    else:        return True class _RandomNameSequence:    """An instance of _RandomNameSequence generates an endless    sequence of unpredictable strings which can safely be incorporated    into file names.  Each string is six characters long.  Multiple    threads can safely use the same instance at the same time.     _RandomNameSequence is an iterator."""     characters = ("abcdefghijklmnopqrstuvwxyz" +                  "ABCDEFGHIJKLMNOPQRSTUVWXYZ" +                  "0123456789-_")     def __init__(self):        self.mutex = _allocate_lock()        self.rng = _Random()        self.normcase = _os.path.normcase     def __iter__(self):        return self     def next(self):        m = self.mutex        c = self.characters        choose = self.rng.choice         m.acquire()        try:            letters = [choose(c) for dummy in "123456"]        finally:            m.release()         return self.normcase(''.join(letters)) def _candidate_tempdir_list():    """Generate a list of candidate temporary directories which    _get_default_tempdir will try."""     dirlist = []     # First, try the environment.    for envname in 'TMPDIR', 'TEMP', 'TMP':        dirname = _os.getenv(envname)        if dirname: dirlist.append(dirname)     # Failing that, try OS-specific locations.    if _os.name == 'mac':        try:            fsr = _Folder.FSFindFolder(_Folders.kOnSystemDisk,                                              _Folders.kTemporaryFolderType, 1)            dirname = fsr.as_pathname()            dirlist.append(dirname)        except _Folder.error:            pass    elif _os.name == 'riscos':        dirname = _os.getenv('Wimp$ScrapDir')        if dirname: dirlist.append(dirname)    elif _os.name == 'nt':        dirlist.extend([ r'c:\temp', r'c:\tmp', r'\temp', r'\tmp' ])    else:        dirlist.extend([ '/tmp', '/var/tmp', '/usr/tmp' ])     # As a last resort, the current directory.    try:        dirlist.append(_os.getcwd())    except (AttributeError, _os.error):        dirlist.append(_os.curdir)     return dirlist def _get_default_tempdir():    """Calculate the default directory to use for temporary files.    This routine should be called exactly once.     We determine whether or not a candidate temp dir is usable by    trying to create and write to a file in that directory.  If this    is successful, the test file is deleted.  To prevent denial of    service, the name of the test file must be randomized."""     namer = _RandomNameSequence()    dirlist = _candidate_tempdir_list()    flags = _text_openflags     for dir in dirlist:        if dir != _os.curdir:            dir = _os.path.normcase(_os.path.abspath(dir))        # Try only a few names per directory.        for seq in xrange(100):            name = namer.next()            filename = _os.path.join(dir, name)            try:                fd = _os.open(filename, flags, 0600)                fp = _os.fdopen(fd, 'w')                fp.write('blat')                fp.close()                _os.unlink(filename)                del fp, fd                return dir            except (OSError, IOError), e:                if e[0] != _errno.EEXIST:                    break # no point trying more names in this directory                pass    raise IOError, (_errno.ENOENT,                    ("No usable temporary directory found in %s" % dirlist)) _name_sequence = None def _get_candidate_names():    """Common setup sequence for all user-callable interfaces."""     global _name_sequence    if _name_sequence is None:        _once_lock.acquire()        try:            if _name_sequence is None:                _name_sequence = _RandomNameSequence()        finally:            _once_lock.release()    return _name_sequence  def _mkstemp_inner(dir, pre, suf, flags):    """Code common to mkstemp, TemporaryFile, and NamedTemporaryFile."""     names = _get_candidate_names()     for seq in xrange(TMP_MAX):        name = names.next()        file = _os.path.join(dir, pre + name + suf)        try:            fd = _os.open(file, flags, 0600)            _set_cloexec(fd)            return (fd, _os.path.abspath(file))        except OSError, e:            if e.errno == _errno.EEXIST:                continue # try again            raise     raise IOError, (_errno.EEXIST, "No usable temporary file name found")  # User visible interfaces. def gettempprefix():    """Accessor for tempdir.template."""    return template tempdir = None def gettempdir():    """Accessor for tempdir.tempdir."""    global tempdir    if tempdir is None:        _once_lock.acquire()        try:            if tempdir is None:                tempdir = _get_default_tempdir()        finally:            _once_lock.release()    return tempdir def mkstemp(suffix="", prefix=template, dir=None, text=False):    """mkstemp([suffix, [prefix, [dir, [text]]]])    User-callable function to create and return a unique temporary    file.  The return value is a pair (fd, name) where fd is the    file descriptor returned by os.open, and name is the filename.     If 'suffix' is specified, the file name will end with that suffix,    otherwise there will be no suffix.     If 'prefix' is specified, the file name will begin with that prefix,    otherwise a default prefix is used.     If 'dir' is specified, the file will be created in that directory,    otherwise a default directory is used.     If 'text' is specified and true, the file is opened in text    mode.  Else (the default) the file is opened in binary mode.  On    some operating systems, this makes no difference.     The file is readable and writable only by the creating user ID.    If the operating system uses permission bits to indicate whether a    file is executable, the file is executable by no one. The file    descriptor is not inherited by children of this process.     Caller is responsible for deleting the file when done with it.    """     if dir is None:        dir = gettempdir()     if text:        flags = _text_openflags    else:        flags = _bin_openflags     return _mkstemp_inner(dir, prefix, suffix, flags)  def mkdtemp(suffix="", prefix=template, dir=None):    """mkdtemp([suffix, [prefix, [dir]]])    User-callable function to create and return a unique temporary    directory.  The return value is the pathname of the directory.     Arguments are as for mkstemp, except that the 'text' argument is    not accepted.     The directory is readable, writable, and searchable only by the    creating user.     Caller is responsible for deleting the directory when done with it.    """     if dir is None:        dir = gettempdir()     names = _get_candidate_names()     for seq in xrange(TMP_MAX):        name = names.next()        file = _os.path.join(dir, prefix + name + suffix)        try:            _os.mkdir(file, 0700)            return file        except OSError, e:            if e.errno == _errno.EEXIST:                continue # try again            raise     raise IOError, (_errno.EEXIST, "No usable temporary directory name found") def mktemp(suffix="", prefix=template, dir=None):    """mktemp([suffix, [prefix, [dir]]])    User-callable function to return a unique temporary file name.  The    file is not created.     Arguments are as for mkstemp, except that the 'text' argument is    not accepted.     This function is unsafe and should not be used.  The file name    refers to a file that did not exist at some point, but by the time    you get around to creating it, someone else may have beaten you to    the punch.    """ ##    from warnings import warn as _warn##    _warn("mktemp is a potential security risk to your program",##          RuntimeWarning, stacklevel=2)     if dir is None:        dir = gettempdir()     names = _get_candidate_names()    for seq in xrange(TMP_MAX):        name = names.next()        file = _os.path.join(dir, prefix + name + suffix)        if not _exists(file):            return file     raise IOError, (_errno.EEXIST, "No usable temporary filename found") class _TemporaryFileWrapper:    """Temporary file wrapper     This class provides a wrapper around files opened for    temporary use.  In particular, it seeks to automatically    remove the file when it is no longer needed.    """     def __init__(self, file, name):        self.file = file        self.name = name        self.close_called = False     def __getattr__(self, name):        file = self.__dict__['file']        a = getattr(file, name)        if type(a) != type(0):            setattr(self, name, a)        return a     # NT provides delete-on-close as a primitive, so we don't need    # the wrapper to do anything special.  We still use it so that    # file.name is useful (i.e. not "(fdopen)") with NamedTemporaryFile.    if _os.name != 'nt':         # Cache the unlinker so we don't get spurious errors at        # shutdown when the module-level "os" is None'd out.  Note        # that this must be referenced as self.unlink, because the        # name TemporaryFileWrapper may also get None'd out before        # __del__ is called.        unlink = _os.unlink         def close(self):            if not self.close_called:                self.close_called = True                self.file.close()                self.unlink(self.name)         def __del__(self):            self.close() def NamedTemporaryFile(mode='w+b', bufsize=-1, suffix="",                       prefix=template, dir=None):    """Create and return a temporary file.    Arguments:    'prefix', 'suffix', 'dir' -- as for mkstemp.    'mode' -- the mode argument to os.fdopen (default "w+b").    'bufsize' -- the buffer size argument to os.fdopen (default -1).    The file is created as mkstemp() would do it.     Returns an object with a file-like interface; the name of the file    is accessible as file.name.  The file will be automatically deleted    when it is closed.    """     if dir is None:        dir = gettempdir()     if 'b' in mode:        flags = _bin_openflags    else:        flags = _text_openflags     # Setting O_TEMPORARY in the flags causes the OS to delete    # the file when it is closed.  This is only supported by Windows.    if _os.name == 'nt':        flags |= _os.O_TEMPORARY     (fd, name) = _mkstemp_inner(dir, prefix, suffix, flags)    file = _os.fdopen(fd, mode, bufsize)    return _TemporaryFileWrapper(file, name) if _os.name != 'posix' or _os.sys.platform == 'cygwin':    # On non-POSIX and Cygwin systems, assume that we cannot unlink a file    # while it is open.    TemporaryFile = NamedTemporaryFile else:    def TemporaryFile(mode='w+b', bufsize=-1, suffix="",                      prefix=template, dir=None):        """Create and return a temporary file.        Arguments:        'prefix', 'suffix', 'dir' -- as for mkstemp.        'mode' -- the mode argument to os.fdopen (default "w+b").        'bufsize' -- the buffer size argument to os.fdopen (default -1).        The file is created as mkstemp() would do it.         Returns an object with a file-like interface.  The file has no        name, and will cease to exist when it is closed.        """         if dir is None:            dir = gettempdir()         if 'b' in mode:            flags = _bin_openflags        else:            flags = _text_openflags         (fd, name) = _mkstemp_inner(dir, prefix, suffix, flags)        try:            _os.unlink(name)            return _os.fdopen(fd, mode, bufsize)        except:            _os.close(fd)            raise