mirror of https://github.com/python/cpython
77 lines
2.8 KiB
Python
77 lines
2.8 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."""
|
||
|
|
|
||
|
|
# 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 os.environ.has_key("PYTHON_DOM"):
|
||
|
|
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
|
||
|
|
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 StandardError: # typically ImportError, or AttributeError
|
||
|
|
continue
|
||
|
|
if _good_enough(dom, features):
|
||
|
|
return dom
|
||
|
|
|
||
|
|
raise ImportError,"no suitable DOM implementation found"
|