zeroinstall/support/xmltools.py

   1 """Convenience functions for handling XML.
   2 @since: 1.9
   3 """
   4
   5 # Copyright (C) 2012, Thomas Leonard
   6 # See the README file for details, or visit http://0install.net.
   7
   8 from xml.dom import Node
   9
  10 def _compare_children(a, b):
  11         ac = a.childNodes
  12         bc = b.childNodes
  13
  14         if ac.length != bc.length:
  15                 return False
  16
  17         for i in range(ac.length):
  18                 if not nodes_equal(ac[i], bc[i]):
  19                         return False
  20
  21         return True
  22
  23 def nodes_equal(a, b):
  24         """Compare two DOM nodes.
  25         Warning: only supports documents containing elements, text nodes and attributes (will crash on comments, etc).
  26         """
  27         if a.nodeType != b.nodeType:
  28                 return False
  29
  30         if a.nodeType == Node.ELEMENT_NODE:
  31                 if a.namespaceURI != b.namespaceURI:
  32                         return False
  33
  34                 if a.nodeName != b.nodeName:
  35                         return False
  36
  37                 a_attrs = set([(name, value) for name, value in a.attributes.itemsNS()])
  38                 b_attrs = set([(name, value) for name, value in b.attributes.itemsNS()])
  39
  40                 if a_attrs != b_attrs:
  41                         #print "%s != %s" % (a_attrs, b_attrs)
  42                         return False
  43
  44                 return _compare_children(a, b)
  45         elif a.nodeType in (Node.TEXT_NODE, Node.CDATA_SECTION_NODE):
  46                 return a.wholeText == b.wholeText
  47         elif a.nodeType == Node.DOCUMENT_NODE:
  48                 return _compare_children(a, b)
  49         else:
  50                 assert 0, ("Unknown node type", a)