[Jython-checkins] jython: Added and slightly tweaked tempfile from:
frank.wierzbicki
jython-checkins at python.org
Wed Mar 21 18:45:53 CET 2012
http://hg.python.org/jython/rev/60f3975016ff
changeset: 6451:60f3975016ff
user: Frank Wierzbicki <fwierzbicki at gmail.com>
date: Wed Mar 21 10:45:37 2012 -0700
summary:
Added and slightly tweaked tempfile from:
http://hg.python.org/cpython/Lib/tempfile.py@22db03646d9b
files:
Lib/tempfile.py | 622 ++++++++++++++++++++++++++++++++++++
1 files changed, 622 insertions(+), 0 deletions(-)
diff --git a/Lib/tempfile.py b/Lib/tempfile.py
new file mode 100644
--- /dev/null
+++ b/Lib/tempfile.py
@@ -0,0 +1,622 @@
+"""Temporary files.
+
+This module provides generic, low- and high-level interfaces for
+creating temporary files and directories. The interfaces listed
+as "safe" just below can be used without fear of race conditions.
+Those listed as "unsafe" cannot, and are provided for backward
+compatibility 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
+ "SpooledTemporaryFile",
+ "mkstemp", "mkdtemp", # low level safe interfaces
+ "mktemp", # deprecated unsafe interface
+ "TMP_MAX", "gettempprefix", # constants
+ "tempdir", "gettempdir"
+ ]
+
+
+# Imports.
+
+import os as _os
+import errno as _errno
+from random import Random as _Random
+
+import platform
+
+is_jython = platform.python_implementation() == "Jython"
+
+try:
+ from cStringIO import StringIO as _StringIO
+except ImportError:
+ from StringIO import StringIO as _StringIO
+
+try:
+ import fcntl as _fcntl
+except ImportError:
+ def _set_cloexec(fd):
+ pass
+else:
+ 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 _thread
+except ImportError:
+ import dummy_thread as _thread
+_allocate_lock = _thread.allocate_lock
+
+_text_openflags = _os.O_RDWR | _os.O_CREAT | _os.O_EXCL
+if hasattr(_os, 'O_NOINHERIT'):
+ _text_openflags |= _os.O_NOINHERIT
+if hasattr(_os, 'O_NOFOLLOW'):
+ _text_openflags |= _os.O_NOFOLLOW
+
+_bin_openflags = _text_openflags
+if hasattr(_os, 'O_BINARY'):
+ _bin_openflags |= _os.O_BINARY
+
+if hasattr(_os, 'TMP_MAX'):
+ TMP_MAX = _os.TMP_MAX
+else:
+ TMP_MAX = 10000
+
+template = "tmp"
+
+# Internal routines.
+
+_once_lock = _allocate_lock()
+
+if hasattr(_os, "lstat"):
+ _stat = _os.lstat
+elif hasattr(_os, "stat"):
+ _stat = _os.stat
+else:
+ # 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.normcase = _os.path.normcase
+
+ @property
+ def rng(self):
+ if is_jython:
+ #A JVM run cannot determine or change its pid so dummy this.
+ cur_pid = 1
+ else:
+ cur_pid = _os.getpid()
+
+ if cur_pid != getattr(self, '_rng_pid', None):
+ self._rng = _Random()
+ self._rng_pid = cur_pid
+ return self._rng
+
+ 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 == '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 tempfile.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):
+ """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):
+ """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):
+ """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, delete=True):
+ self.file = file
+ self.name = name
+ self.close_called = False
+ self.delete = delete
+
+ def __getattr__(self, name):
+ # Attribute lookups are delegated to the underlying file
+ # and cached for non-numeric results
+ # (i.e. methods are cached, closed and friends are not)
+ file = self.__dict__['file']
+ a = getattr(file, name)
+ if not issubclass(type(a), type(0)):
+ setattr(self, name, a)
+ return a
+
+ # The underlying __enter__ method returns the wrong object
+ # (self.file) so override it to return the wrapper
+ def __enter__(self):
+ self.file.__enter__()
+ return self
+
+ # 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()
+ if self.delete:
+ self.unlink(self.name)
+
+ def __del__(self):
+ self.close()
+
+ # Need to trap __exit__ as well to ensure the file gets
+ # deleted when used in a with statement
+ def __exit__(self, exc, value, tb):
+ result = self.file.__exit__(exc, value, tb)
+ self.close()
+ return result
+ else:
+ def __exit__(self, exc, value, tb):
+ self.file.__exit__(exc, value, tb)
+
+
+def NamedTemporaryFile(mode='w+b', bufsize=-1, suffix="",
+ prefix=template, dir=None, delete=True):
+ """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).
+ 'delete' -- whether the file is deleted on close (default True).
+ 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 unless the 'delete' argument is set to False.
+ """
+
+ 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' and delete:
+ flags |= _os.O_TEMPORARY
+
+ (fd, name) = _mkstemp_inner(dir, prefix, suffix, flags)
+ file = _os.fdopen(fd, mode, bufsize)
+ return _TemporaryFileWrapper(file, name, delete)
+
+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
+
+class SpooledTemporaryFile:
+ """Temporary file wrapper, specialized to switch from
+ StringIO to a real file when it exceeds a certain size or
+ when a fileno is needed.
+ """
+ _rolled = False
+
+ def __init__(self, max_size=0, mode='w+b', bufsize=-1,
+ suffix="", prefix=template, dir=None):
+ self._file = _StringIO()
+ self._max_size = max_size
+ self._rolled = False
+ self._TemporaryFileArgs = (mode, bufsize, suffix, prefix, dir)
+
+ def _check(self, file):
+ if self._rolled: return
+ max_size = self._max_size
+ if max_size and file.tell() > max_size:
+ self.rollover()
+
+ def rollover(self):
+ if self._rolled: return
+ file = self._file
+ newfile = self._file = TemporaryFile(*self._TemporaryFileArgs)
+ del self._TemporaryFileArgs
+
+ newfile.write(file.getvalue())
+ newfile.seek(file.tell(), 0)
+
+ self._rolled = True
+
+ # The method caching trick from NamedTemporaryFile
+ # won't work here, because _file may change from a
+ # _StringIO instance to a real file. So we list
+ # all the methods directly.
+
+ # Context management protocol
+ def __enter__(self):
+ if self._file.closed:
+ raise ValueError("Cannot enter context with closed file")
+ return self
+
+ def __exit__(self, exc, value, tb):
+ self._file.close()
+
+ # file protocol
+ def __iter__(self):
+ return self._file.__iter__()
+
+ def close(self):
+ self._file.close()
+
+ @property
+ def closed(self):
+ return self._file.closed
+
+ @property
+ def encoding(self):
+ return self._file.encoding
+
+ def fileno(self):
+ self.rollover()
+ return self._file.fileno()
+
+ def flush(self):
+ self._file.flush()
+
+ def isatty(self):
+ return self._file.isatty()
+
+ @property
+ def mode(self):
+ return self._file.mode
+
+ @property
+ def name(self):
+ return self._file.name
+
+ @property
+ def newlines(self):
+ return self._file.newlines
+
+ def next(self):
+ return self._file.next
+
+ def read(self, *args):
+ return self._file.read(*args)
+
+ def readline(self, *args):
+ return self._file.readline(*args)
+
+ def readlines(self, *args):
+ return self._file.readlines(*args)
+
+ def seek(self, *args):
+ self._file.seek(*args)
+
+ @property
+ def softspace(self):
+ return self._file.softspace
+
+ def tell(self):
+ return self._file.tell()
+
+ def truncate(self):
+ self._file.truncate()
+
+ def write(self, s):
+ file = self._file
+ rv = file.write(s)
+ self._check(file)
+ return rv
+
+ def writelines(self, iterable):
+ file = self._file
+ rv = file.writelines(iterable)
+ self._check(file)
+ return rv
+
+ def xreadlines(self, *args):
+ return self._file.xreadlines(*args)
--
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