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|
| | import re |
| |
|
| | xpath_tokenizer_re = re.compile( |
| | r"(" |
| | r"'[^']*'|\"[^\"]*\"|" |
| | r"::|" |
| | r"//?|" |
| | r"\.\.|" |
| | r"\(\)|" |
| | r"!=|" |
| | r"[/.*:\[\]\(\)@=])|" |
| | r"((?:\{[^}]+\})?[^/\[\]\(\)@!=\s]+)|" |
| | r"\s+" |
| | ) |
| |
|
| | def xpath_tokenizer(pattern, namespaces=None): |
| | default_namespace = namespaces.get('') if namespaces else None |
| | parsing_attribute = False |
| | for token in xpath_tokenizer_re.findall(pattern): |
| | ttype, tag = token |
| | if tag and tag[0] != "{": |
| | if ":" in tag: |
| | prefix, uri = tag.split(":", 1) |
| | try: |
| | if not namespaces: |
| | raise KeyError |
| | yield ttype, "{%s}%s" % (namespaces[prefix], uri) |
| | except KeyError: |
| | raise SyntaxError("prefix %r not found in prefix map" % prefix) from None |
| | elif default_namespace and not parsing_attribute: |
| | yield ttype, "{%s}%s" % (default_namespace, tag) |
| | else: |
| | yield token |
| | parsing_attribute = False |
| | else: |
| | yield token |
| | parsing_attribute = ttype == '@' |
| |
|
| |
|
| | def get_parent_map(context): |
| | parent_map = context.parent_map |
| | if parent_map is None: |
| | context.parent_map = parent_map = {} |
| | for p in context.root.iter(): |
| | for e in p: |
| | parent_map[e] = p |
| | return parent_map |
| |
|
| |
|
| | def _is_wildcard_tag(tag): |
| | return tag[:3] == '{*}' or tag[-2:] == '}*' |
| |
|
| |
|
| | def _prepare_tag(tag): |
| | _isinstance, _str = isinstance, str |
| | if tag == '{*}*': |
| | |
| | |
| | |
| | def select(context, result): |
| | for elem in result: |
| | if _isinstance(elem.tag, _str): |
| | yield elem |
| | elif tag == '{}*': |
| | |
| | def select(context, result): |
| | for elem in result: |
| | el_tag = elem.tag |
| | if _isinstance(el_tag, _str) and el_tag[0] != '{': |
| | yield elem |
| | elif tag[:3] == '{*}': |
| | |
| | suffix = tag[2:] |
| | no_ns = slice(-len(suffix), None) |
| | tag = tag[3:] |
| | def select(context, result): |
| | for elem in result: |
| | el_tag = elem.tag |
| | if el_tag == tag or _isinstance(el_tag, _str) and el_tag[no_ns] == suffix: |
| | yield elem |
| | elif tag[-2:] == '}*': |
| | |
| | ns = tag[:-1] |
| | ns_only = slice(None, len(ns)) |
| | def select(context, result): |
| | for elem in result: |
| | el_tag = elem.tag |
| | if _isinstance(el_tag, _str) and el_tag[ns_only] == ns: |
| | yield elem |
| | else: |
| | raise RuntimeError(f"internal parser error, got {tag}") |
| | return select |
| |
|
| |
|
| | def prepare_child(next, token): |
| | tag = token[1] |
| | if _is_wildcard_tag(tag): |
| | select_tag = _prepare_tag(tag) |
| | def select(context, result): |
| | def select_child(result): |
| | for elem in result: |
| | yield from elem |
| | return select_tag(context, select_child(result)) |
| | else: |
| | if tag[:2] == '{}': |
| | tag = tag[2:] |
| | def select(context, result): |
| | for elem in result: |
| | for e in elem: |
| | if e.tag == tag: |
| | yield e |
| | return select |
| |
|
| | def prepare_star(next, token): |
| | def select(context, result): |
| | for elem in result: |
| | yield from elem |
| | return select |
| |
|
| | def prepare_self(next, token): |
| | def select(context, result): |
| | yield from result |
| | return select |
| |
|
| | def prepare_descendant(next, token): |
| | try: |
| | token = next() |
| | except StopIteration: |
| | return |
| | if token[0] == "*": |
| | tag = "*" |
| | elif not token[0]: |
| | tag = token[1] |
| | else: |
| | raise SyntaxError("invalid descendant") |
| |
|
| | if _is_wildcard_tag(tag): |
| | select_tag = _prepare_tag(tag) |
| | def select(context, result): |
| | def select_child(result): |
| | for elem in result: |
| | for e in elem.iter(): |
| | if e is not elem: |
| | yield e |
| | return select_tag(context, select_child(result)) |
| | else: |
| | if tag[:2] == '{}': |
| | tag = tag[2:] |
| | def select(context, result): |
| | for elem in result: |
| | for e in elem.iter(tag): |
| | if e is not elem: |
| | yield e |
| | return select |
| |
|
| | def prepare_parent(next, token): |
| | def select(context, result): |
| | |
| | parent_map = get_parent_map(context) |
| | result_map = {} |
| | for elem in result: |
| | if elem in parent_map: |
| | parent = parent_map[elem] |
| | if parent not in result_map: |
| | result_map[parent] = None |
| | yield parent |
| | return select |
| |
|
| | def prepare_predicate(next, token): |
| | |
| | |
| | signature = [] |
| | predicate = [] |
| | while 1: |
| | try: |
| | token = next() |
| | except StopIteration: |
| | return |
| | if token[0] == "]": |
| | break |
| | if token == ('', ''): |
| | |
| | continue |
| | if token[0] and token[0][:1] in "'\"": |
| | token = "'", token[0][1:-1] |
| | signature.append(token[0] or "-") |
| | predicate.append(token[1]) |
| | signature = "".join(signature) |
| | |
| | if signature == "@-": |
| | |
| | key = predicate[1] |
| | def select(context, result): |
| | for elem in result: |
| | if elem.get(key) is not None: |
| | yield elem |
| | return select |
| | if signature == "@-='" or signature == "@-!='": |
| | |
| | key = predicate[1] |
| | value = predicate[-1] |
| | def select(context, result): |
| | for elem in result: |
| | if elem.get(key) == value: |
| | yield elem |
| | def select_negated(context, result): |
| | for elem in result: |
| | if (attr_value := elem.get(key)) is not None and attr_value != value: |
| | yield elem |
| | return select_negated if '!=' in signature else select |
| | if signature == "-" and not re.match(r"\-?\d+$", predicate[0]): |
| | |
| | tag = predicate[0] |
| | def select(context, result): |
| | for elem in result: |
| | if elem.find(tag) is not None: |
| | yield elem |
| | return select |
| | if signature == ".='" or signature == ".!='" or ( |
| | (signature == "-='" or signature == "-!='") |
| | and not re.match(r"\-?\d+$", predicate[0])): |
| | |
| | tag = predicate[0] |
| | value = predicate[-1] |
| | if tag: |
| | def select(context, result): |
| | for elem in result: |
| | for e in elem.findall(tag): |
| | if "".join(e.itertext()) == value: |
| | yield elem |
| | break |
| | def select_negated(context, result): |
| | for elem in result: |
| | for e in elem.iterfind(tag): |
| | if "".join(e.itertext()) != value: |
| | yield elem |
| | break |
| | else: |
| | def select(context, result): |
| | for elem in result: |
| | if "".join(elem.itertext()) == value: |
| | yield elem |
| | def select_negated(context, result): |
| | for elem in result: |
| | if "".join(elem.itertext()) != value: |
| | yield elem |
| | return select_negated if '!=' in signature else select |
| | if signature == "-" or signature == "-()" or signature == "-()-": |
| | |
| | if signature == "-": |
| | |
| | index = int(predicate[0]) - 1 |
| | if index < 0: |
| | raise SyntaxError("XPath position >= 1 expected") |
| | else: |
| | if predicate[0] != "last": |
| | raise SyntaxError("unsupported function") |
| | if signature == "-()-": |
| | try: |
| | index = int(predicate[2]) - 1 |
| | except ValueError: |
| | raise SyntaxError("unsupported expression") |
| | if index > -2: |
| | raise SyntaxError("XPath offset from last() must be negative") |
| | else: |
| | index = -1 |
| | def select(context, result): |
| | parent_map = get_parent_map(context) |
| | for elem in result: |
| | try: |
| | parent = parent_map[elem] |
| | |
| | elems = list(parent.findall(elem.tag)) |
| | if elems[index] is elem: |
| | yield elem |
| | except (IndexError, KeyError): |
| | pass |
| | return select |
| | raise SyntaxError("invalid predicate") |
| |
|
| | ops = { |
| | "": prepare_child, |
| | "*": prepare_star, |
| | ".": prepare_self, |
| | "..": prepare_parent, |
| | "//": prepare_descendant, |
| | "[": prepare_predicate, |
| | } |
| |
|
| | _cache = {} |
| |
|
| | class _SelectorContext: |
| | parent_map = None |
| | def __init__(self, root): |
| | self.root = root |
| |
|
| | |
| |
|
| | |
| | |
| |
|
| | def iterfind(elem, path, namespaces=None): |
| | |
| | if path[-1:] == "/": |
| | path = path + "*" |
| |
|
| | cache_key = (path,) |
| | if namespaces: |
| | cache_key += tuple(sorted(namespaces.items())) |
| |
|
| | try: |
| | selector = _cache[cache_key] |
| | except KeyError: |
| | if len(_cache) > 100: |
| | _cache.clear() |
| | if path[:1] == "/": |
| | raise SyntaxError("cannot use absolute path on element") |
| | next = iter(xpath_tokenizer(path, namespaces)).__next__ |
| | try: |
| | token = next() |
| | except StopIteration: |
| | return |
| | selector = [] |
| | while 1: |
| | try: |
| | selector.append(ops[token[0]](next, token)) |
| | except StopIteration: |
| | raise SyntaxError("invalid path") from None |
| | try: |
| | token = next() |
| | if token[0] == "/": |
| | token = next() |
| | except StopIteration: |
| | break |
| | _cache[cache_key] = selector |
| | |
| | result = [elem] |
| | context = _SelectorContext(elem) |
| | for select in selector: |
| | result = select(context, result) |
| | return result |
| |
|
| | |
| | |
| |
|
| | def find(elem, path, namespaces=None): |
| | return next(iterfind(elem, path, namespaces), None) |
| |
|
| | |
| | |
| |
|
| | def findall(elem, path, namespaces=None): |
| | return list(iterfind(elem, path, namespaces)) |
| |
|
| | |
| | |
| |
|
| | def findtext(elem, path, default=None, namespaces=None): |
| | try: |
| | elem = next(iterfind(elem, path, namespaces)) |
| | return elem.text or "" |
| | except StopIteration: |
| | return default |
| |
|