| | """Registration facilities for DOM. This module should not be used |
| | directly. Instead, the functions getDOMImplementation and |
| | registerDOMImplementation should be imported from xml.dom.""" |
| |
|
| | |
| | |
| | |
| |
|
| | import sys |
| |
|
| | well_known_implementations = { |
| | 'minidom':'xml.dom.minidom', |
| | '4DOM': 'xml.dom.DOMImplementation', |
| | } |
| |
|
| | |
| | |
| |
|
| | 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 not sys.flags.ignore_environment and "PYTHON_DOM" in os.environ: |
| | return getDOMImplementation(name = os.environ["PYTHON_DOM"]) |
| |
|
| | |
| | |
| | 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: |
| | 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) |
| |
|