155 lines
4.4 KiB
Python
155 lines
4.4 KiB
Python
"""Temporary files and filenames."""
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# XXX This tries to be not UNIX specific, but I don't know beans about
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# how to choose a temp directory or filename on MS-DOS or other
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# systems so it may have to be changed...
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import os
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# Parameters that the caller may set to override the defaults
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tempdir = None
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template = None
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def gettempdir():
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"""Function to calculate the directory to use."""
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global tempdir
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if tempdir is not None:
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return tempdir
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try:
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pwd = os.getcwd()
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except (AttributeError, os.error):
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pwd = os.curdir
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attempdirs = ['/usr/tmp', '/tmp', pwd]
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if os.name == 'nt':
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attempdirs.insert(0, 'C:\\TEMP')
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attempdirs.insert(0, '\\TEMP')
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elif os.name == 'mac':
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import macfs, MACFS
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try:
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refnum, dirid = macfs.FindFolder(MACFS.kOnSystemDisk,
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MACFS.kTemporaryFolderType, 1)
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dirname = macfs.FSSpec((refnum, dirid, '')).as_pathname()
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attempdirs.insert(0, dirname)
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except macfs.error:
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pass
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for envname in 'TMPDIR', 'TEMP', 'TMP':
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if os.environ.has_key(envname):
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attempdirs.insert(0, os.environ[envname])
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testfile = gettempprefix() + 'test'
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for dir in attempdirs:
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try:
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filename = os.path.join(dir, testfile)
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if os.name == 'posix':
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try:
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fd = os.open(filename, os.O_RDWR|os.O_CREAT|os.O_EXCL, 0700)
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except OSError:
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pass
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else:
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fp = os.fdopen(fd, 'w')
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fp.write('blat')
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fp.close()
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os.unlink(filename)
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del fp, fd
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tempdir = dir
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break
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else:
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fp = open(filename, 'w')
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fp.write('blat')
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fp.close()
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os.unlink(filename)
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tempdir = dir
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break
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except IOError:
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pass
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if tempdir is None:
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msg = "Can't find a usable temporary directory amongst " + `attempdirs`
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raise IOError, msg
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return tempdir
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_pid = None
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def gettempprefix():
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"""Function to calculate a prefix of the filename to use."""
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global template, _pid
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if os.name == 'posix' and _pid and _pid != os.getpid():
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# Our pid changed; we must have forked -- zap the template
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template = None
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if template is None:
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if os.name == 'posix':
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_pid = os.getpid()
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template = '@' + `_pid` + '.'
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elif os.name == 'nt':
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template = '~' + `os.getpid()` + '-'
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elif os.name == 'mac':
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template = 'Python-Tmp-'
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else:
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template = 'tmp' # XXX might choose a better one
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return template
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# Counter for generating unique names
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counter = 0
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def mktemp(suffix=""):
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"""User-callable function to return a unique temporary file name."""
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global counter
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dir = gettempdir()
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pre = gettempprefix()
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while 1:
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counter = counter + 1
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file = os.path.join(dir, pre + `counter` + suffix)
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if not os.path.exists(file):
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return file
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class TemporaryFileWrapper:
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"""Temporary file wrapper
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This class provides a wrapper around files opened for temporary use.
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In particular, it seeks to automatically remove the file when it is
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no longer needed.
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"""
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def __init__(self, file, path):
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self.file = file
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self.path = path
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def close(self):
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self.file.close()
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os.unlink(self.path)
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def __del__(self):
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try: self.close()
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except: pass
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def __getattr__(self, name):
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file = self.__dict__['file']
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a = getattr(file, name)
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if type(a) != type(0):
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setattr(self, name, a)
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return a
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def TemporaryFile(mode='w+b', bufsize=-1, suffix=""):
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"""Create and return a temporary file (opened read-write by default)."""
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name = mktemp(suffix)
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if os.name == 'posix':
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# Unix -- be very careful
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fd = os.open(name, os.O_RDWR|os.O_CREAT|os.O_EXCL, 0700)
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try:
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os.unlink(name)
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return os.fdopen(fd, mode, bufsize)
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except:
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os.close(fd)
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raise
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else:
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# Non-unix -- can't unlink file that's still open, use wrapper
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file = open(name, mode, bufsize)
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return TemporaryFileWrapper(file, name)
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