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https://github.com/ytdl-org/youtube-dl
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[compat] Improve compat_etree_iterfind for Py2.6
Adapted from https://raw.githubusercontent.com/python/cpython/2.7/Lib/xml/etree/ElementPath.py
This commit is contained in:
dirkf
parent
06da64ee51
commit
34484e49f5
@ -2720,9 +2720,217 @@ if sys.version_info < (2, 7):
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xpath = xpath.encode('ascii')
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return xpath
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def compat_etree_iterfind(element, match):
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for from_ in element.findall(match):
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yield from_
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# further code below based on CPython 2.7 source
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import functools
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_xpath_tokenizer_re = re.compile(r'''(?x)
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( # (1)
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'[^']*'|"[^"]*"| # quoted strings, or
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::|//?|\.\.|\(\)|[/.*:[\]()@=] # navigation specials
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)| # or (2)
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((?:\{[^}]+\})?[^/[\]()@=\s]+)| # token: optional {ns}, no specials
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\s+ # or white space
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''')
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def _xpath_tokenizer(pattern, namespaces=None):
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for token in _xpath_tokenizer_re.findall(pattern):
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tag = token[1]
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if tag and tag[0] != "{" and ":" in tag:
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try:
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if not namespaces:
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raise KeyError
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prefix, uri = tag.split(":", 1)
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yield token[0], "{%s}%s" % (namespaces[prefix], uri)
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except KeyError:
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raise SyntaxError("prefix %r not found in prefix map" % prefix)
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else:
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yield token
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def _get_parent_map(context):
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parent_map = context.parent_map
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if parent_map is None:
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context.parent_map = parent_map = {}
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for p in context.root.getiterator():
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for e in p:
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parent_map[e] = p
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return parent_map
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def _select(context, result, filter_fn=lambda *_: True):
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for elem in result:
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for e in elem:
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if filter_fn(e, elem):
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yield e
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def _prepare_child(next_, token):
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tag = token[1]
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return functools.partial(_select, filter_fn=lambda e, _: e.tag == tag)
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def _prepare_star(next_, token):
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return _select
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def _prepare_self(next_, token):
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return lambda _, result: (e for e in result)
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def _prepare_descendant(next_, token):
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token = next(next_)
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if token[0] == "*":
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tag = "*"
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elif not token[0]:
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tag = token[1]
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else:
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raise SyntaxError("invalid descendant")
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def select(context, result):
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for elem in result:
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for e in elem.getiterator(tag):
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if e is not elem:
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yield e
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return select
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def _prepare_parent(next_, token):
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def select(context, result):
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# FIXME: raise error if .. is applied at toplevel?
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parent_map = _get_parent_map(context)
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result_map = {}
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for elem in result:
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if elem in parent_map:
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parent = parent_map[elem]
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if parent not in result_map:
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result_map[parent] = None
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yield parent
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return select
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def _prepare_predicate(next_, token):
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signature = []
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predicate = []
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for token in next_:
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if token[0] == "]":
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break
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if token[0] and token[0][:1] in "'\"":
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token = "'", token[0][1:-1]
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signature.append(token[0] or "-")
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predicate.append(token[1])
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def select(context, result, filter_fn=lambda _: True):
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for elem in result:
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if filter_fn(elem):
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yield elem
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signature = "".join(signature)
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# use signature to determine predicate type
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if signature == "@-":
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# [@attribute] predicate
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key = predicate[1]
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return functools.partial(
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select, filter_fn=lambda el: el.get(key) is not None)
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if signature == "@-='":
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# [@attribute='value']
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key = predicate[1]
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value = predicate[-1]
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return functools.partial(
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select, filter_fn=lambda el: el.get(key) == value)
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if signature == "-" and not re.match(r"\d+$", predicate[0]):
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# [tag]
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tag = predicate[0]
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return functools.partial(
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select, filter_fn=lambda el: el.find(tag) is not None)
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if signature == "-='" and not re.match(r"\d+$", predicate[0]):
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# [tag='value']
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tag = predicate[0]
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value = predicate[-1]
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def itertext(el):
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for e in el.getiterator():
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e = e.text
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if e:
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yield e
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def select(context, result):
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for elem in result:
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for e in elem.findall(tag):
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if "".join(itertext(e)) == value:
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yield elem
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break
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return select
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if signature == "-" or signature == "-()" or signature == "-()-":
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# [index] or [last()] or [last()-index]
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if signature == "-":
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index = int(predicate[0]) - 1
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else:
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if predicate[0] != "last":
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raise SyntaxError("unsupported function")
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if signature == "-()-":
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try:
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index = int(predicate[2]) - 1
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except ValueError:
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raise SyntaxError("unsupported expression")
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else:
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index = -1
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def select(context, result):
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parent_map = _get_parent_map(context)
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for elem in result:
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try:
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parent = parent_map[elem]
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# FIXME: what if the selector is "*" ?
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elems = list(parent.findall(elem.tag))
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if elems[index] is elem:
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yield elem
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except (IndexError, KeyError):
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pass
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return select
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raise SyntaxError("invalid predicate")
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ops = {
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"": _prepare_child,
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"*": _prepare_star,
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".": _prepare_self,
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"..": _prepare_parent,
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"//": _prepare_descendant,
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"[": _prepare_predicate,
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}
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_cache = {}
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class _SelectorContext:
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parent_map = None
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def __init__(self, root):
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self.root = root
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##
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# Generate all matching objects.
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def compat_etree_iterfind(elem, path, namespaces=None):
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# compile selector pattern
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if path[-1:] == "/":
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path = path + "*" # implicit all (FIXME: keep this?)
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try:
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selector = _cache[path]
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except KeyError:
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if len(_cache) > 100:
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_cache.clear()
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if path[:1] == "/":
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raise SyntaxError("cannot use absolute path on element")
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tokens = _xpath_tokenizer(path, namespaces)
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selector = []
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for token in tokens:
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if token[0] == "/":
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continue
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try:
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selector.append(ops[token[0]](tokens, token))
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except StopIteration:
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raise SyntaxError("invalid path")
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_cache[path] = selector
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# execute selector pattern
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result = [elem]
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context = _SelectorContext(elem)
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for select in selector:
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result = select(context, result)
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return result
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# end of code based on CPython 2.7 source
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else:
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compat_xpath = lambda xpath: xpath
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