[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 2024-05-28 16:38:20 +01:00
parent 06da64ee51
commit 34484e49f5

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