Edit File: nsclasses.pxi
# module-level API for namespace implementations cdef class LxmlRegistryError(LxmlError): """Base class of lxml registry errors. """ cdef class NamespaceRegistryError(LxmlRegistryError): """Error registering a namespace extension. """ @cython.internal cdef class _NamespaceRegistry: u"Dictionary-like namespace registry" cdef object _ns_uri cdef bytes _ns_uri_utf cdef dict _entries cdef char* _c_ns_uri_utf def __cinit__(self, ns_uri): self._ns_uri = ns_uri if ns_uri is None: self._ns_uri_utf = None self._c_ns_uri_utf = NULL else: self._ns_uri_utf = _utf8(ns_uri) self._c_ns_uri_utf = _cstr(self._ns_uri_utf) self._entries = {} def update(self, class_dict_iterable): u"""update(self, class_dict_iterable) Forgivingly update the registry. ``class_dict_iterable`` may be a dict or some other iterable that yields (name, value) pairs. If a value does not match the required type for this registry, or if the name starts with '_', it will be silently discarded. This allows registrations at the module or class level using vars(), globals() etc.""" if hasattr(class_dict_iterable, u'items'): class_dict_iterable = class_dict_iterable.items() for name, item in class_dict_iterable: if (name is None or name[:1] != '_') and callable(item): self[name] = item def __getitem__(self, name): if name is not None: name = _utf8(name) return self._get(name) def __delitem__(self, name): if name is not None: name = _utf8(name) del self._entries[name] cdef object _get(self, object name): cdef python.PyObject* dict_result dict_result = python.PyDict_GetItem(self._entries, name) if dict_result is NULL: raise KeyError, u"Name not registered." return <object>dict_result cdef object _getForString(self, char* name): cdef python.PyObject* dict_result dict_result = python.PyDict_GetItem(self._entries, name) if dict_result is NULL: raise KeyError, u"Name not registered." return <object>dict_result def __iter__(self): return iter(self._entries) def items(self): return list(self._entries.items()) def iteritems(self): return iter(self._entries.items()) def clear(self): self._entries.clear() def __call__(self, obj): # Usage as decorator: # ns = lookup.get_namespace("...") # @ns('abc') # class element(ElementBase): pass # # @ns # class elementname(ElementBase): pass if obj is None or python._isString(obj): # @ns(None) or @ns('tag') return partial(self.__deco, obj) # plain @ns decorator self[obj.__name__] = obj return obj def __deco(self, name, obj): self[name] = obj return obj @cython.final @cython.internal cdef class _ClassNamespaceRegistry(_NamespaceRegistry): u"Dictionary-like registry for namespace implementation classes" def __setitem__(self, name, item): if not isinstance(item, type) or not issubclass(item, ElementBase): raise NamespaceRegistryError, \ u"Registered element classes must be subtypes of ElementBase" if name is not None: name = _utf8(name) self._entries[name] = item def __repr__(self): return u"Namespace(%r)" % self._ns_uri cdef class ElementNamespaceClassLookup(FallbackElementClassLookup): u"""ElementNamespaceClassLookup(self, fallback=None) Element class lookup scheme that searches the Element class in the Namespace registry. Usage: >>> lookup = ElementNamespaceClassLookup() >>> ns_elements = lookup.get_namespace("http://schema.org/Movie") >>> @ns_elements ... class movie(ElementBase): ... "Element implementation for 'movie' tag (using class name) in schema namespace." >>> @ns_elements("movie") ... class MovieElement(ElementBase): ... "Element implementation for 'movie' tag (explicit tag name) in schema namespace." """ cdef dict _namespace_registries def __cinit__(self): self._namespace_registries = {} def __init__(self, ElementClassLookup fallback=None): FallbackElementClassLookup.__init__(self, fallback) self._lookup_function = _find_nselement_class def get_namespace(self, ns_uri): u"""get_namespace(self, ns_uri) Retrieve the namespace object associated with the given URI. Pass None for the empty namespace. Creates a new namespace object if it does not yet exist.""" if ns_uri: ns_utf = _utf8(ns_uri) else: ns_utf = None try: return self._namespace_registries[ns_utf] except KeyError: registry = self._namespace_registries[ns_utf] = \ _ClassNamespaceRegistry(ns_uri) return registry cdef object _find_nselement_class(state, _Document doc, xmlNode* c_node): cdef python.PyObject* dict_result cdef ElementNamespaceClassLookup lookup cdef _NamespaceRegistry registry if state is None: return _lookupDefaultElementClass(None, doc, c_node) lookup = <ElementNamespaceClassLookup>state if c_node.type != tree.XML_ELEMENT_NODE: return _callLookupFallback(lookup, doc, c_node) c_namespace_utf = _getNs(c_node) if c_namespace_utf is not NULL: dict_result = python.PyDict_GetItem( lookup._namespace_registries, <unsigned char*>c_namespace_utf) else: dict_result = python.PyDict_GetItem( lookup._namespace_registries, None) if dict_result is not NULL: registry = <_NamespaceRegistry>dict_result classes = registry._entries if c_node.name is not NULL: dict_result = python.PyDict_GetItem( classes, <unsigned char*>c_node.name) else: dict_result = NULL if dict_result is NULL: dict_result = python.PyDict_GetItem(classes, None) if dict_result is not NULL: return <object>dict_result return _callLookupFallback(lookup, doc, c_node) ################################################################################ # XPath extension functions cdef dict __FUNCTION_NAMESPACE_REGISTRIES __FUNCTION_NAMESPACE_REGISTRIES = {} def FunctionNamespace(ns_uri): u"""FunctionNamespace(ns_uri) Retrieve the function namespace object associated with the given URI. Creates a new one if it does not yet exist. A function namespace can only be used to register extension functions. Usage: >>> ns_functions = FunctionNamespace("http://schema.org/Movie") >>> @ns_functions # uses function name ... def add2(x): ... return x + 2 >>> @ns_functions("add3") # uses explicit name ... def add_three(x): ... return x + 3 """ ns_utf = _utf8(ns_uri) if ns_uri else None try: return __FUNCTION_NAMESPACE_REGISTRIES[ns_utf] except KeyError: registry = __FUNCTION_NAMESPACE_REGISTRIES[ns_utf] = \ _XPathFunctionNamespaceRegistry(ns_uri) return registry @cython.internal cdef class _FunctionNamespaceRegistry(_NamespaceRegistry): def __setitem__(self, name, item): if not callable(item): raise NamespaceRegistryError, \ u"Registered functions must be callable." if not name: raise ValueError, \ u"extensions must have non empty names" self._entries[_utf8(name)] = item def __repr__(self): return u"FunctionNamespace(%r)" % self._ns_uri @cython.final @cython.internal cdef class _XPathFunctionNamespaceRegistry(_FunctionNamespaceRegistry): cdef object _prefix cdef bytes _prefix_utf property prefix: u"Namespace prefix for extension functions." def __del__(self): self._prefix = None # no prefix configured self._prefix_utf = None def __get__(self): if self._prefix is None: return '' else: return self._prefix def __set__(self, prefix): if prefix == '': prefix = None # empty prefix self._prefix_utf = _utf8(prefix) if prefix is not None else None self._prefix = prefix cdef list _find_all_extension_prefixes(): u"Internal lookup function to find all function prefixes for XSLT/XPath." cdef _XPathFunctionNamespaceRegistry registry cdef list ns_prefixes = [] for registry in __FUNCTION_NAMESPACE_REGISTRIES.itervalues(): if registry._prefix_utf is not None: if registry._ns_uri_utf is not None: ns_prefixes.append( (registry._prefix_utf, registry._ns_uri_utf)) return ns_prefixes