Lib/tempfile.py

   1 # Temporary file name allocation
   2 #
   3 # XXX This tries to be not UNIX specific, but I don't know beans about
   4 # how to choose a temp directory or filename on MS-DOS or other
   5 # systems so it may have to be changed...
   6
   7
   8 import os
   9
  10
  11 # Parameters that the caller may set to override the defaults
  12
  13 tempdir = None
  14 template = None
  15
  16
  17 # Function to calculate the directory to use
  18
  19 def gettempdir():
  20         global tempdir
  21         if tempdir == None:
  22                 try:
  23                         tempdir = os.environ['TMPDIR']
  24                 except (KeyError, AttributeError):
  25                         if os.name == 'posix':
  26                                 tempdir = '/usr/tmp' # XXX Why not /tmp?
  27                         else:
  28                                 tempdir = os.getcwd() # XXX Is this OK?
  29         return tempdir
  30
  31
  32 # Function to calculate a prefix of the filename to use
  33
  34 def gettempprefix():
  35         global template
  36         if template == None:
  37                 if os.name == 'posix':
  38                         template = '@' + `os.getpid()` + '.'
  39                 else:
  40                         template = 'tmp' # XXX might choose a better one
  41         return template
  42
  43
  44 # Counter for generating unique names
  45
  46 counter = 0
  47
  48
  49 # User-callable function to return a unique temporary file name
  50
  51 def mktemp():
  52         global counter
  53         dir = gettempdir()
  54         pre = gettempprefix()
  55         while 1:
  56                 counter = counter + 1
  57                 file = os.path.join(dir, pre + `counter`)
  58                 if not os.path.exists(file):
  59                         return file