Lib/email/_compat22.py

   1 # Copyright (C) 2002 Python Software Foundation
   2 # Author: barry@zope.com
   3
   4 """Module containing compatibility functions for Python 2.1.
   5 """
   6
   7 from __future__ import generators
   8 from __future__ import division
   9 from cStringIO import StringIO
  10 from types import StringTypes
  11
  12
  13 \f
  14 # This function will become a method of the Message class
  15 def walk(self):
  16     """Walk over the message tree, yielding each subpart.
  17
  18     The walk is performed in depth-first order.  This method is a
  19     generator.
  20     """
  21     yield self
  22     if self.is_multipart():
  23         for subpart in self.get_payload():
  24             for subsubpart in subpart.walk():
  25                 yield subsubpart
  26
  27
  28 # Python 2.2 spells floor division //
  29 def _floordiv(i, j):
  30     """Do a floor division, i/j."""
  31     return i // j
  32
  33
  34 def _isstring(obj):
  35     return isinstance(obj, StringTypes)
  36
  37
  38 \f
  39 # These two functions are imported into the Iterators.py interface module.
  40 # The Python 2.2 version uses generators for efficiency.
  41 def body_line_iterator(msg):
  42     """Iterate over the parts, returning string payloads line-by-line."""
  43     for subpart in msg.walk():
  44         payload = subpart.get_payload()
  45         if _isstring(payload):
  46             for line in StringIO(payload):
  47                 yield line
  48
  49
  50 def typed_subpart_iterator(msg, maintype='text', subtype=None):
  51     """Iterate over the subparts with a given MIME type.
  52
  53     Use `maintype' as the main MIME type to match against; this defaults to
  54     "text".  Optional `subtype' is the MIME subtype to match against; if
  55     omitted, only the main type is matched.
  56     """
  57     for subpart in msg.walk():
  58         if subpart.get_main_type('text') == maintype:
  59             if subtype is None or subpart.get_subtype('plain') == subtype:
  60                 yield subpart