cpython/Lib/xml/dom/domreg.py
Georg Brandl b044b2a701 Merged revisions 74821,74828-74831,74833,74835 via svnmerge from
svn+ssh://svn.python.org/python/branches/py3k

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  r74821 | georg.brandl | 2009-09-16 11:42:19 +0200 (Mi, 16 Sep 2009) | 1 line

  #6885: run python 3 as python3.
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  r74828 | georg.brandl | 2009-09-16 16:23:20 +0200 (Mi, 16 Sep 2009) | 1 line

  Use true booleans.
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  r74829 | georg.brandl | 2009-09-16 16:24:29 +0200 (Mi, 16 Sep 2009) | 1 line

  Small PEP8 correction.
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  r74830 | georg.brandl | 2009-09-16 16:36:22 +0200 (Mi, 16 Sep 2009) | 1 line

  Use true booleans.
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  r74831 | georg.brandl | 2009-09-16 17:54:04 +0200 (Mi, 16 Sep 2009) | 1 line

  Use true booleans and PEP8 for argdefaults.
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  r74833 | georg.brandl | 2009-09-16 17:58:14 +0200 (Mi, 16 Sep 2009) | 1 line

  Last round of adapting style of documenting argument default values.
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  r74835 | georg.brandl | 2009-09-16 18:00:31 +0200 (Mi, 16 Sep 2009) | 33 lines

  Merged revisions 74817-74820,74822-74824 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

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    r74817 | georg.brandl | 2009-09-16 11:05:11 +0200 (Mi, 16 Sep 2009) | 1 line

    Make deprecation notices as visible as warnings are right now.
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    r74818 | georg.brandl | 2009-09-16 11:23:04 +0200 (Mi, 16 Sep 2009) | 1 line

    #6880: add reference to classes section in exceptions section, which comes earlier.
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    r74819 | georg.brandl | 2009-09-16 11:24:57 +0200 (Mi, 16 Sep 2009) | 1 line

    #6876: fix base class constructor invocation in example.
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    r74820 | georg.brandl | 2009-09-16 11:30:48 +0200 (Mi, 16 Sep 2009) | 1 line

    #6891: comment out dead link to Unicode article.
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    r74822 | georg.brandl | 2009-09-16 12:12:06 +0200 (Mi, 16 Sep 2009) | 1 line

    #5621: refactor description of how class/instance attributes interact on a.x=a.x+1 or augassign.
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    r74823 | georg.brandl | 2009-09-16 15:06:22 +0200 (Mi, 16 Sep 2009) | 1 line

    Remove strange trailing commas.
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    r74824 | georg.brandl | 2009-09-16 15:11:06 +0200 (Mi, 16 Sep 2009) | 1 line

    #6892: fix optparse example involving help option.
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2009-09-16 16:05:59 +00:00

99 lines
3.4 KiB
Python

"""Registration facilities for DOM. This module should not be used
directly. Instead, the functions getDOMImplementation and
registerDOMImplementation should be imported from xml.dom."""
from xml.dom.minicompat import * # isinstance, StringTypes
# This is a list of well-known implementations. Well-known names
# should be published by posting to xml-sig@python.org, and are
# subsequently recorded in this file.
well_known_implementations = {
'minidom':'xml.dom.minidom',
'4DOM': 'xml.dom.DOMImplementation',
}
# DOM implementations not officially registered should register
# themselves with their
registered = {}
def registerDOMImplementation(name, factory):
"""registerDOMImplementation(name, factory)
Register the factory function with the name. The factory function
should return an object which implements the DOMImplementation
interface. The factory function can either return the same object,
or a new one (e.g. if that implementation supports some
customization)."""
registered[name] = factory
def _good_enough(dom, features):
"_good_enough(dom, features) -> Return 1 if the dom offers the features"
for f,v in features:
if not dom.hasFeature(f,v):
return 0
return 1
def getDOMImplementation(name=None, features=()):
"""getDOMImplementation(name = None, features = ()) -> DOM implementation.
Return a suitable DOM implementation. The name is either
well-known, the module name of a DOM implementation, or None. If
it is not None, imports the corresponding module and returns
DOMImplementation object if the import succeeds.
If name is not given, consider the available implementations to
find one with the required feature set. If no implementation can
be found, raise an ImportError. The features list must be a sequence
of (feature, version) pairs which are passed to hasFeature."""
import os
creator = None
mod = well_known_implementations.get(name)
if mod:
mod = __import__(mod, {}, {}, ['getDOMImplementation'])
return mod.getDOMImplementation()
elif name:
return registered[name]()
elif "PYTHON_DOM" in os.environ:
return getDOMImplementation(name = os.environ["PYTHON_DOM"])
# User did not specify a name, try implementations in arbitrary
# order, returning the one that has the required features
if isinstance(features, str):
features = _parse_feature_string(features)
for creator in registered.values():
dom = creator()
if _good_enough(dom, features):
return dom
for creator in well_known_implementations.keys():
try:
dom = getDOMImplementation(name = creator)
except Exception: # typically ImportError, or AttributeError
continue
if _good_enough(dom, features):
return dom
raise ImportError("no suitable DOM implementation found")
def _parse_feature_string(s):
features = []
parts = s.split()
i = 0
length = len(parts)
while i < length:
feature = parts[i]
if feature[0] in "0123456789":
raise ValueError("bad feature name: %r" % (feature,))
i = i + 1
version = None
if i < length:
v = parts[i]
if v[0] in "0123456789":
i = i + 1
version = v
features.append((feature, version))
return tuple(features)