Edit File: extensions.pxi
# support for extension functions in XPath and XSLT cdef class XPathError(LxmlError): """Base class of all XPath errors. """ cdef class XPathEvalError(XPathError): """Error during XPath evaluation. """ cdef class XPathFunctionError(XPathEvalError): """Internal error looking up an XPath extension function. """ cdef class XPathResultError(XPathEvalError): """Error handling an XPath result. """ # forward declarations ctypedef int (*_register_function)(void* ctxt, name_utf, ns_uri_utf) cdef class _ExsltRegExp ################################################################################ # Base class for XSLT and XPath evaluation contexts: functions, namespaces, ... @cython.internal cdef class _BaseContext: cdef xpath.xmlXPathContext* _xpathCtxt cdef _Document _doc cdef dict _extensions cdef list _namespaces cdef list _global_namespaces cdef dict _utf_refs cdef dict _function_cache cdef dict _eval_context_dict cdef bint _build_smart_strings # for exception handling and temporary reference keeping: cdef _TempStore _temp_refs cdef set _temp_documents cdef _ExceptionContext _exc cdef _ErrorLog _error_log def __cinit__(self): self._xpathCtxt = NULL def __init__(self, namespaces, extensions, error_log, enable_regexp, build_smart_strings): cdef _ExsltRegExp _regexp cdef dict new_extensions cdef list ns self._utf_refs = {} self._global_namespaces = [] self._function_cache = {} self._eval_context_dict = None self._error_log = error_log if extensions is not None: # convert extensions to UTF-8 if isinstance(extensions, dict): extensions = (extensions,) # format: [ {(ns, name):function} ] -> {(ns_utf, name_utf):function} new_extensions = {} for extension in extensions: for (ns_uri, name), function in extension.items(): if name is None: raise ValueError, u"extensions must have non empty names" ns_utf = self._to_utf(ns_uri) name_utf = self._to_utf(name) new_extensions[(ns_utf, name_utf)] = function extensions = new_extensions or None if namespaces is not None: if isinstance(namespaces, dict): namespaces = namespaces.items() if namespaces: ns = [] for prefix, ns_uri in namespaces: if prefix is None or not prefix: raise TypeError, \ u"empty namespace prefix is not supported in XPath" if ns_uri is None or not ns_uri: raise TypeError, \ u"setting default namespace is not supported in XPath" prefix_utf = self._to_utf(prefix) ns_uri_utf = self._to_utf(ns_uri) ns.append( (prefix_utf, ns_uri_utf) ) namespaces = ns else: namespaces = None self._doc = None self._exc = _ExceptionContext() self._extensions = extensions self._namespaces = namespaces self._temp_refs = _TempStore() self._temp_documents = set() self._build_smart_strings = build_smart_strings if enable_regexp: _regexp = _ExsltRegExp() _regexp._register_in_context(self) cdef _BaseContext _copy(self): cdef _BaseContext context if self._namespaces is not None: namespaces = self._namespaces[:] else: namespaces = None context = self.__class__(namespaces, None, self._error_log, False, self._build_smart_strings) if self._extensions is not None: context._extensions = self._extensions.copy() return context cdef bytes _to_utf(self, s): u"Convert to UTF-8 and keep a reference to the encoded string" cdef python.PyObject* dict_result if s is None: return None dict_result = python.PyDict_GetItem(self._utf_refs, s) if dict_result is not NULL: return <bytes>dict_result utf = _utf8(s) self._utf_refs[s] = utf if python.IS_PYPY: # use C level refs, PyPy refs are not enough! python.Py_INCREF(utf) return utf cdef void _set_xpath_context(self, xpath.xmlXPathContext* xpathCtxt): self._xpathCtxt = xpathCtxt xpathCtxt.userData = <void*>self xpathCtxt.error = _receiveXPathError @cython.final cdef _register_context(self, _Document doc): self._doc = doc self._exc.clear() @cython.final cdef _cleanup_context(self): #xpath.xmlXPathRegisteredNsCleanup(self._xpathCtxt) #self.unregisterGlobalNamespaces() if python.IS_PYPY: # clean up double refs in PyPy (see "_to_utf()" method) for ref in self._utf_refs.itervalues(): python.Py_DECREF(ref) self._utf_refs.clear() self._eval_context_dict = None self._doc = None @cython.final cdef _release_context(self): if self._xpathCtxt is not NULL: self._xpathCtxt.userData = NULL self._xpathCtxt = NULL # namespaces (internal UTF-8 methods with leading '_') cdef addNamespace(self, prefix, ns_uri): cdef list namespaces if prefix is None: raise TypeError, u"empty prefix is not supported in XPath" prefix_utf = self._to_utf(prefix) ns_uri_utf = self._to_utf(ns_uri) new_item = (prefix_utf, ns_uri_utf) if self._namespaces is None: self._namespaces = [new_item] else: namespaces = [] for item in self._namespaces: if item[0] == prefix_utf: item = new_item new_item = None namespaces.append(item) if new_item is not None: namespaces.append(new_item) self._namespaces = namespaces if self._xpathCtxt is not NULL: xpath.xmlXPathRegisterNs( self._xpathCtxt, _xcstr(prefix_utf), _xcstr(ns_uri_utf)) cdef registerNamespace(self, prefix, ns_uri): if prefix is None: raise TypeError, u"empty prefix is not supported in XPath" prefix_utf = self._to_utf(prefix) ns_uri_utf = self._to_utf(ns_uri) self._global_namespaces.append(prefix_utf) xpath.xmlXPathRegisterNs(self._xpathCtxt, _xcstr(prefix_utf), _xcstr(ns_uri_utf)) cdef registerLocalNamespaces(self): if self._namespaces is None: return for prefix_utf, ns_uri_utf in self._namespaces: xpath.xmlXPathRegisterNs( self._xpathCtxt, _xcstr(prefix_utf), _xcstr(ns_uri_utf)) cdef registerGlobalNamespaces(self): cdef list ns_prefixes = _find_all_extension_prefixes() if python.PyList_GET_SIZE(ns_prefixes) > 0: for prefix_utf, ns_uri_utf in ns_prefixes: self._global_namespaces.append(prefix_utf) xpath.xmlXPathRegisterNs( self._xpathCtxt, _xcstr(prefix_utf), _xcstr(ns_uri_utf)) cdef unregisterGlobalNamespaces(self): if python.PyList_GET_SIZE(self._global_namespaces) > 0: for prefix_utf in self._global_namespaces: xpath.xmlXPathRegisterNs(self._xpathCtxt, _xcstr(prefix_utf), NULL) del self._global_namespaces[:] cdef void _unregisterNamespace(self, prefix_utf): xpath.xmlXPathRegisterNs(self._xpathCtxt, _xcstr(prefix_utf), NULL) # extension functions cdef int _addLocalExtensionFunction(self, ns_utf, name_utf, function) except -1: if self._extensions is None: self._extensions = {} self._extensions[(ns_utf, name_utf)] = function return 0 cdef registerGlobalFunctions(self, void* ctxt, _register_function reg_func): cdef python.PyObject* dict_result cdef dict d for ns_utf, ns_functions in __FUNCTION_NAMESPACE_REGISTRIES.iteritems(): dict_result = python.PyDict_GetItem( self._function_cache, ns_utf) if dict_result is not NULL: d = <dict>dict_result else: d = {} self._function_cache[ns_utf] = d for name_utf, function in ns_functions.iteritems(): d[name_utf] = function reg_func(ctxt, name_utf, ns_utf) cdef registerLocalFunctions(self, void* ctxt, _register_function reg_func): cdef python.PyObject* dict_result cdef dict d if self._extensions is None: return # done last_ns = None d = None for (ns_utf, name_utf), function in self._extensions.iteritems(): if ns_utf is not last_ns or d is None: last_ns = ns_utf dict_result = python.PyDict_GetItem( self._function_cache, ns_utf) if dict_result is not NULL: d = <dict>dict_result else: d = {} self._function_cache[ns_utf] = d d[name_utf] = function reg_func(ctxt, name_utf, ns_utf) cdef unregisterAllFunctions(self, void* ctxt, _register_function unreg_func): for ns_utf, functions in self._function_cache.iteritems(): for name_utf in functions: unreg_func(ctxt, name_utf, ns_utf) cdef unregisterGlobalFunctions(self, void* ctxt, _register_function unreg_func): for ns_utf, functions in self._function_cache.items(): for name_utf in functions: if self._extensions is None or \ (ns_utf, name_utf) not in self._extensions: unreg_func(ctxt, name_utf, ns_utf) @cython.final cdef _find_cached_function(self, const_xmlChar* c_ns_uri, const_xmlChar* c_name): u"""Lookup an extension function in the cache and return it. Parameters: c_ns_uri may be NULL, c_name must not be NULL """ cdef python.PyObject* c_dict cdef python.PyObject* dict_result c_dict = python.PyDict_GetItem( self._function_cache, None if c_ns_uri is NULL else c_ns_uri) if c_dict is not NULL: dict_result = python.PyDict_GetItem( <object>c_dict, <unsigned char*>c_name) if dict_result is not NULL: return <object>dict_result return None # Python access to the XPath context for extension functions @property def context_node(self): cdef xmlNode* c_node if self._xpathCtxt is NULL: raise XPathError, \ u"XPath context is only usable during the evaluation" c_node = self._xpathCtxt.node if c_node is NULL: raise XPathError, u"no context node" if c_node.doc != self._xpathCtxt.doc: raise XPathError, \ u"document-external context nodes are not supported" if self._doc is None: raise XPathError, u"document context is missing" return _elementFactory(self._doc, c_node) @property def eval_context(self): if self._eval_context_dict is None: self._eval_context_dict = {} return self._eval_context_dict # Python reference keeping during XPath function evaluation @cython.final cdef _release_temp_refs(self): u"Free temporarily referenced objects from this context." self._temp_refs.clear() self._temp_documents.clear() @cython.final cdef _hold(self, obj): u"""A way to temporarily hold references to nodes in the evaluator. This is needed because otherwise nodes created in XPath extension functions would be reference counted too soon, during the XPath evaluation. This is most important in the case of exceptions. """ cdef _Element element if isinstance(obj, _Element): self._temp_refs.add(obj) self._temp_documents.add((<_Element>obj)._doc) return elif _isString(obj) or not python.PySequence_Check(obj): return for o in obj: if isinstance(o, _Element): #print "Holding element:", <int>element._c_node self._temp_refs.add(o) #print "Holding document:", <int>element._doc._c_doc self._temp_documents.add((<_Element>o)._doc) @cython.final cdef _Document _findDocumentForNode(self, xmlNode* c_node): u"""If an XPath expression returns an element from a different document than the current context document, we call this to see if it was possibly created by an extension and is a known document instance. """ cdef _Document doc for doc in self._temp_documents: if doc is not None and doc._c_doc is c_node.doc: return doc return None # libxml2 keeps these error messages in a static array in its code # and doesn't give us access to them ... cdef tuple LIBXML2_XPATH_ERROR_MESSAGES = ( b"Ok", b"Number encoding", b"Unfinished literal", b"Start of literal", b"Expected $ for variable reference", b"Undefined variable", b"Invalid predicate", b"Invalid expression", b"Missing closing curly brace", b"Unregistered function", b"Invalid operand", b"Invalid type", b"Invalid number of arguments", b"Invalid context size", b"Invalid context position", b"Memory allocation error", b"Syntax error", b"Resource error", b"Sub resource error", b"Undefined namespace prefix", b"Encoding error", b"Char out of XML range", b"Invalid or incomplete context", b"Stack usage error", b"Forbidden variable\n", b"?? Unknown error ??\n", ) cdef void _forwardXPathError(void* c_ctxt, xmlerror.xmlError* c_error) with gil: cdef xmlerror.xmlError error cdef int xpath_code if c_error.message is not NULL: error.message = c_error.message else: xpath_code = c_error.code - xmlerror.XML_XPATH_EXPRESSION_OK if 0 <= xpath_code < len(LIBXML2_XPATH_ERROR_MESSAGES): error.message = _cstr(LIBXML2_XPATH_ERROR_MESSAGES[xpath_code]) else: error.message = b"unknown error" error.domain = c_error.domain error.code = c_error.code error.level = c_error.level error.line = c_error.line error.int2 = c_error.int1 # column error.file = c_error.file error.node = NULL (<_BaseContext>c_ctxt)._error_log._receive(&error) cdef void _receiveXPathError(void* c_context, xmlerror.xmlError* error) nogil: if not __DEBUG: return if c_context is NULL: _forwardError(NULL, error) else: _forwardXPathError(c_context, error) def Extension(module, function_mapping=None, *, ns=None): u"""Extension(module, function_mapping=None, ns=None) Build a dictionary of extension functions from the functions defined in a module or the methods of an object. As second argument, you can pass an additional mapping of attribute names to XPath function names, or a list of function names that should be taken. The ``ns`` keyword argument accepts a namespace URI for the XPath functions. """ cdef dict functions = {} if isinstance(function_mapping, dict): for function_name, xpath_name in function_mapping.items(): functions[(ns, xpath_name)] = getattr(module, function_name) else: if function_mapping is None: function_mapping = [ name for name in dir(module) if not name.startswith(u'_') ] for function_name in function_mapping: functions[(ns, function_name)] = getattr(module, function_name) return functions ################################################################################ # EXSLT regexp implementation @cython.final @cython.internal cdef class _ExsltRegExp: cdef dict _compile_map def __cinit__(self): self._compile_map = {} cdef _make_string(self, value): if _isString(value): return value elif isinstance(value, list): # node set: take recursive text concatenation of first element if python.PyList_GET_SIZE(value) == 0: return u'' firstnode = value[0] if _isString(firstnode): return firstnode elif isinstance(firstnode, _Element): c_text = tree.xmlNodeGetContent((<_Element>firstnode)._c_node) if c_text is NULL: raise MemoryError() try: return funicode(c_text) finally: tree.xmlFree(c_text) else: return unicode(firstnode) else: return unicode(value) cdef _compile(self, rexp, ignore_case): cdef python.PyObject* c_result rexp = self._make_string(rexp) key = (rexp, ignore_case) c_result = python.PyDict_GetItem(self._compile_map, key) if c_result is not NULL: return <object>c_result py_flags = re.UNICODE if ignore_case: py_flags = py_flags | re.IGNORECASE rexp_compiled = re.compile(rexp, py_flags) self._compile_map[key] = rexp_compiled return rexp_compiled def test(self, ctxt, s, rexp, flags=u''): flags = self._make_string(flags) s = self._make_string(s) rexpc = self._compile(rexp, u'i' in flags) if rexpc.search(s) is None: return False else: return True def match(self, ctxt, s, rexp, flags=u''): cdef list result_list flags = self._make_string(flags) s = self._make_string(s) rexpc = self._compile(rexp, u'i' in flags) if u'g' in flags: results = rexpc.findall(s) if not results: return () else: result = rexpc.search(s) if not result: return () results = [ result.group() ] results.extend( result.groups(u'') ) result_list = [] root = Element(u'matches') join_groups = u''.join for s_match in results: if python.PyTuple_CheckExact(s_match): s_match = join_groups(s_match) elem = SubElement(root, u'match') elem.text = s_match result_list.append(elem) return result_list def replace(self, ctxt, s, rexp, flags, replacement): replacement = self._make_string(replacement) flags = self._make_string(flags) s = self._make_string(s) rexpc = self._compile(rexp, u'i' in flags) if u'g' in flags: count = 0 else: count = 1 return rexpc.sub(replacement, s, count) cdef _register_in_context(self, _BaseContext context): ns = b"http://exslt.org/regular-expressions" context._addLocalExtensionFunction(ns, b"test", self.test) context._addLocalExtensionFunction(ns, b"match", self.match) context._addLocalExtensionFunction(ns, b"replace", self.replace) ################################################################################ # helper functions cdef xpath.xmlXPathObject* _wrapXPathObject(object obj, _Document doc, _BaseContext context) except NULL: cdef xpath.xmlNodeSet* resultSet cdef _Element fake_node = None cdef xmlNode* c_node if isinstance(obj, unicode): obj = _utf8(obj) if isinstance(obj, bytes): # libxml2 copies the string value return xpath.xmlXPathNewCString(_cstr(obj)) if isinstance(obj, bool): return xpath.xmlXPathNewBoolean(obj) if python.PyNumber_Check(obj): return xpath.xmlXPathNewFloat(obj) if obj is None: resultSet = xpath.xmlXPathNodeSetCreate(NULL) elif isinstance(obj, _Element): resultSet = xpath.xmlXPathNodeSetCreate((<_Element>obj)._c_node) elif python.PySequence_Check(obj): resultSet = xpath.xmlXPathNodeSetCreate(NULL) try: for value in obj: if isinstance(value, _Element): if context is not None: context._hold(value) xpath.xmlXPathNodeSetAdd(resultSet, (<_Element>value)._c_node) else: if context is None or doc is None: raise XPathResultError, \ f"Non-Element values not supported at this point - got {value!r}" # support strings by appending text nodes to an Element if isinstance(value, unicode): value = _utf8(value) if isinstance(value, bytes): if fake_node is None: fake_node = _makeElement("text-root", NULL, doc, None, None, None, None, None, None) context._hold(fake_node) else: # append a comment node to keep the text nodes separate c_node = tree.xmlNewDocComment(doc._c_doc, <unsigned char*>"") if c_node is NULL: raise MemoryError() tree.xmlAddChild(fake_node._c_node, c_node) context._hold(value) c_node = tree.xmlNewDocText(doc._c_doc, _xcstr(value)) if c_node is NULL: raise MemoryError() tree.xmlAddChild(fake_node._c_node, c_node) xpath.xmlXPathNodeSetAdd(resultSet, c_node) else: raise XPathResultError, \ f"This is not a supported node-set result: {value!r}" except: xpath.xmlXPathFreeNodeSet(resultSet) raise else: raise XPathResultError, f"Unknown return type: {python._fqtypename(obj).decode('utf8')}" return xpath.xmlXPathWrapNodeSet(resultSet) cdef object _unwrapXPathObject(xpath.xmlXPathObject* xpathObj, _Document doc, _BaseContext context): if xpathObj.type == xpath.XPATH_UNDEFINED: raise XPathResultError, u"Undefined xpath result" elif xpathObj.type == xpath.XPATH_NODESET: return _createNodeSetResult(xpathObj, doc, context) elif xpathObj.type == xpath.XPATH_BOOLEAN: return xpathObj.boolval elif xpathObj.type == xpath.XPATH_NUMBER: return xpathObj.floatval elif xpathObj.type == xpath.XPATH_STRING: stringval = funicode(xpathObj.stringval) if context._build_smart_strings: stringval = _elementStringResultFactory( stringval, None, None, 0) return stringval elif xpathObj.type == xpath.XPATH_POINT: raise NotImplementedError, u"XPATH_POINT" elif xpathObj.type == xpath.XPATH_RANGE: raise NotImplementedError, u"XPATH_RANGE" elif xpathObj.type == xpath.XPATH_LOCATIONSET: raise NotImplementedError, u"XPATH_LOCATIONSET" elif xpathObj.type == xpath.XPATH_USERS: raise NotImplementedError, u"XPATH_USERS" elif xpathObj.type == xpath.XPATH_XSLT_TREE: return _createNodeSetResult(xpathObj, doc, context) else: raise XPathResultError, f"Unknown xpath result {xpathObj.type}" cdef object _createNodeSetResult(xpath.xmlXPathObject* xpathObj, _Document doc, _BaseContext context): cdef xmlNode* c_node cdef int i cdef list result result = [] if xpathObj.nodesetval is NULL: return result for i in range(xpathObj.nodesetval.nodeNr): c_node = xpathObj.nodesetval.nodeTab[i] _unpackNodeSetEntry(result, c_node, doc, context, xpathObj.type == xpath.XPATH_XSLT_TREE) return result cdef _unpackNodeSetEntry(list results, xmlNode* c_node, _Document doc, _BaseContext context, bint is_fragment): cdef xmlNode* c_child if _isElement(c_node): if c_node.doc != doc._c_doc and c_node.doc._private is NULL: # XXX: works, but maybe not always the right thing to do? # XPath: only runs when extensions create or copy trees # -> we store Python refs to these, so that is OK # XSLT: can it leak when merging trees from multiple sources? c_node = tree.xmlDocCopyNode(c_node, doc._c_doc, 1) # FIXME: call _instantiateElementFromXPath() instead? results.append( _fakeDocElementFactory(doc, c_node)) elif c_node.type == tree.XML_TEXT_NODE or \ c_node.type == tree.XML_CDATA_SECTION_NODE or \ c_node.type == tree.XML_ATTRIBUTE_NODE: results.append( _buildElementStringResult(doc, c_node, context)) elif c_node.type == tree.XML_NAMESPACE_DECL: results.append( (funicodeOrNone((<xmlNs*>c_node).prefix), funicodeOrNone((<xmlNs*>c_node).href)) ) elif c_node.type == tree.XML_DOCUMENT_NODE or \ c_node.type == tree.XML_HTML_DOCUMENT_NODE: # ignored for everything but result tree fragments if is_fragment: c_child = c_node.children while c_child is not NULL: _unpackNodeSetEntry(results, c_child, doc, context, 0) c_child = c_child.next elif c_node.type == tree.XML_XINCLUDE_START or \ c_node.type == tree.XML_XINCLUDE_END: pass else: raise NotImplementedError, \ f"Not yet implemented result node type: {c_node.type}" cdef void _freeXPathObject(xpath.xmlXPathObject* xpathObj): u"""Free the XPath object, but *never* free the *content* of node sets. Python dealloc will do that for us. """ if xpathObj.nodesetval is not NULL: xpath.xmlXPathFreeNodeSet(xpathObj.nodesetval) xpathObj.nodesetval = NULL xpath.xmlXPathFreeObject(xpathObj) cdef _Element _instantiateElementFromXPath(xmlNode* c_node, _Document doc, _BaseContext context): # NOTE: this may copy the element - only call this when it can't leak if c_node.doc != doc._c_doc and c_node.doc._private is NULL: # not from the context document and not from a fake document # either => may still be from a known document, e.g. one # created by an extension function node_doc = context._findDocumentForNode(c_node) if node_doc is None: # not from a known document at all! => can only make a # safety copy here c_node = tree.xmlDocCopyNode(c_node, doc._c_doc, 1) else: doc = node_doc return _fakeDocElementFactory(doc, c_node) ################################################################################ # special str/unicode subclasses @cython.final cdef class _ElementUnicodeResult(unicode): cdef _Element _parent cdef readonly object attrname cdef readonly bint is_tail cdef readonly bint is_text cdef readonly bint is_attribute def getparent(self): return self._parent cdef object _PyElementUnicodeResult if python.IS_PYPY: class _PyElementUnicodeResult(unicode): # we need to use a Python class here, or PyPy will crash on creation # https://bitbucket.org/pypy/pypy/issues/2021/pypy3-pytype_ready-crashes-for-extension def getparent(self): return self._parent class _ElementStringResult(bytes): # we need to use a Python class here, bytes cannot be C-subclassed # in Pyrex/Cython def getparent(self): return self._parent cdef object _elementStringResultFactory(string_value, _Element parent, attrname, bint is_tail): cdef _ElementUnicodeResult uresult cdef bint is_text cdef bint is_attribute = attrname is not None if parent is None: is_text = 0 else: is_text = not (is_tail or is_attribute) if type(string_value) is bytes: result = _ElementStringResult(string_value) result._parent = parent result.is_attribute = is_attribute result.is_tail = is_tail result.is_text = is_text result.attrname = attrname return result elif python.IS_PYPY: result = _PyElementUnicodeResult(string_value) result._parent = parent result.is_attribute = is_attribute result.is_tail = is_tail result.is_text = is_text result.attrname = attrname return result else: uresult = _ElementUnicodeResult(string_value) uresult._parent = parent uresult.is_attribute = is_attribute uresult.is_tail = is_tail uresult.is_text = is_text uresult.attrname = attrname return uresult cdef object _buildElementStringResult(_Document doc, xmlNode* c_node, _BaseContext context): cdef _Element parent = None cdef object attrname = None cdef xmlNode* c_element cdef bint is_tail if c_node.type == tree.XML_ATTRIBUTE_NODE: attrname = _namespacedName(c_node) is_tail = 0 s = tree.xmlNodeGetContent(c_node) try: value = funicode(s) finally: tree.xmlFree(s) c_element = NULL else: #assert c_node.type == tree.XML_TEXT_NODE or c_node.type == tree.XML_CDATA_SECTION_NODE, "invalid node type" # may be tail text or normal text value = funicode(c_node.content) c_element = _previousElement(c_node) is_tail = c_element is not NULL if not context._build_smart_strings: return value if c_element is NULL: # non-tail text or attribute text c_element = c_node.parent while c_element is not NULL and not _isElement(c_element): c_element = c_element.parent if c_element is not NULL: parent = _instantiateElementFromXPath(c_element, doc, context) return _elementStringResultFactory( value, parent, attrname, is_tail) ################################################################################ # callbacks for XPath/XSLT extension functions cdef void _extension_function_call(_BaseContext context, function, xpath.xmlXPathParserContext* ctxt, int nargs): cdef _Document doc cdef xpath.xmlXPathObject* obj cdef list args cdef int i doc = context._doc try: args = [] for i in range(nargs): obj = xpath.valuePop(ctxt) o = _unwrapXPathObject(obj, doc, context) _freeXPathObject(obj) args.append(o) args.reverse() res = function(context, *args) # wrap result for XPath consumption obj = _wrapXPathObject(res, doc, context) # prevent Python from deallocating elements handed to libxml2 context._hold(res) xpath.valuePush(ctxt, obj) except: xpath.xmlXPathErr(ctxt, xpath.XPATH_EXPR_ERROR) context._exc._store_raised() finally: return # swallow any further exceptions # lookup the function by name and call it cdef void _xpath_function_call(xpath.xmlXPathParserContext* ctxt, int nargs) with gil: cdef _BaseContext context cdef xpath.xmlXPathContext* rctxt = ctxt.context context = <_BaseContext> rctxt.userData try: function = context._find_cached_function(rctxt.functionURI, rctxt.function) if function is not None: _extension_function_call(context, function, ctxt, nargs) else: xpath.xmlXPathErr(ctxt, xpath.XPATH_UNKNOWN_FUNC_ERROR) context._exc._store_exception(XPathFunctionError( f"XPath function '{_namespacedNameFromNsName(rctxt.functionURI, rctxt.function)}' not found")) except: # may not be the right error, but we need to tell libxml2 *something* xpath.xmlXPathErr(ctxt, xpath.XPATH_UNKNOWN_FUNC_ERROR) context._exc._store_raised() finally: return # swallow any further exceptions