You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
324 lines
10 KiB
324 lines
10 KiB
#
|
|
# ElementTree
|
|
# $Id: ElementPath.py 3375 2008-02-13 08:05:08Z fredrik $
|
|
#
|
|
# limited xpath support for element trees
|
|
#
|
|
# history:
|
|
# 2003-05-23 fl created
|
|
# 2003-05-28 fl added support for // etc
|
|
# 2003-08-27 fl fixed parsing of periods in element names
|
|
# 2007-09-10 fl new selection engine
|
|
# 2007-09-12 fl fixed parent selector
|
|
# 2007-09-13 fl added iterfind; changed findall to return a list
|
|
# 2007-11-30 fl added namespaces support
|
|
# 2009-10-30 fl added child element value filter
|
|
#
|
|
# Copyright (c) 2003-2009 by Fredrik Lundh. All rights reserved.
|
|
#
|
|
# fredrik@pythonware.com
|
|
# http://www.pythonware.com
|
|
#
|
|
# --------------------------------------------------------------------
|
|
# The ElementTree toolkit is
|
|
#
|
|
# Copyright (c) 1999-2009 by Fredrik Lundh
|
|
#
|
|
# By obtaining, using, and/or copying this software and/or its
|
|
# associated documentation, you agree that you have read, understood,
|
|
# and will comply with the following terms and conditions:
|
|
#
|
|
# Permission to use, copy, modify, and distribute this software and
|
|
# its associated documentation for any purpose and without fee is
|
|
# hereby granted, provided that the above copyright notice appears in
|
|
# all copies, and that both that copyright notice and this permission
|
|
# notice appear in supporting documentation, and that the name of
|
|
# Secret Labs AB or the author not be used in advertising or publicity
|
|
# pertaining to distribution of the software without specific, written
|
|
# prior permission.
|
|
#
|
|
# SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
|
|
# TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT-
|
|
# ABILITY AND FITNESS. IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR
|
|
# BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
|
|
# DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
|
|
# WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
|
|
# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
|
|
# OF THIS SOFTWARE.
|
|
# --------------------------------------------------------------------
|
|
|
|
# Licensed to PSF under a Contributor Agreement.
|
|
# See http://www.python.org/psf/license for licensing details.
|
|
|
|
##
|
|
# Implementation module for XPath support. There's usually no reason
|
|
# to import this module directly; the <b>ElementTree</b> does this for
|
|
# you, if needed.
|
|
##
|
|
|
|
import re
|
|
|
|
xpath_tokenizer_re = re.compile(
|
|
r"("
|
|
r"'[^']*'|\"[^\"]*\"|"
|
|
r"::|"
|
|
r"//?|"
|
|
r"\.\.|"
|
|
r"\(\)|"
|
|
r"[/.*:\[\]\(\)@=])|"
|
|
r"((?:\{[^}]+\})?[^/\[\]\(\)@=\s]+)|"
|
|
r"\s+"
|
|
)
|
|
|
|
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:
|
|
prefix, uri = tag.split(":", 1)
|
|
if not namespaces:
|
|
raise KeyError
|
|
yield token[0], "{%s}%s" % (namespaces[prefix], uri)
|
|
except KeyError:
|
|
raise SyntaxError("prefix %r not found in prefix map" % prefix) from None
|
|
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.iter():
|
|
for e in p:
|
|
parent_map[e] = p
|
|
return parent_map
|
|
|
|
def prepare_child(next, token):
|
|
tag = token[1]
|
|
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")
|
|
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):
|
|
# 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):
|
|
# FIXME: replace with real parser!!! refs:
|
|
# http://effbot.org/zone/simple-iterator-parser.htm
|
|
# http://javascript.crockford.com/tdop/tdop.html
|
|
signature = []
|
|
predicate = []
|
|
while 1:
|
|
try:
|
|
token = next()
|
|
except StopIteration:
|
|
return
|
|
if token[0] == "]":
|
|
break
|
|
if token == ('', ''):
|
|
# ignore whitespace
|
|
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)
|
|
# use signature to determine predicate type
|
|
if signature == "@-":
|
|
# [@attribute] predicate
|
|
key = predicate[1]
|
|
def select(context, result):
|
|
for elem in result:
|
|
if elem.get(key) is not None:
|
|
yield elem
|
|
return select
|
|
if signature == "@-='":
|
|
# [@attribute='value']
|
|
key = predicate[1]
|
|
value = predicate[-1]
|
|
def select(context, result):
|
|
for elem in result:
|
|
if elem.get(key) == value:
|
|
yield elem
|
|
return select
|
|
if signature == "-" and not re.match(r"\-?\d+$", predicate[0]):
|
|
# [tag]
|
|
tag = predicate[0]
|
|
def select(context, result):
|
|
for elem in result:
|
|
if elem.find(tag) is not None:
|
|
yield elem
|
|
return select
|
|
if signature == ".='" or (signature == "-='" and not re.match(r"\-?\d+$", predicate[0])):
|
|
# [.='value'] or [tag='value']
|
|
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
|
|
else:
|
|
def select(context, result):
|
|
for elem in result:
|
|
if "".join(elem.itertext()) == value:
|
|
yield elem
|
|
return select
|
|
if signature == "-" or signature == "-()" or signature == "-()-":
|
|
# [index] or [last()] or [last()-index]
|
|
if signature == "-":
|
|
# [index]
|
|
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]
|
|
# 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 iterfind(elem, path, namespaces=None):
|
|
# compile selector pattern
|
|
cache_key = (path, None if namespaces is None
|
|
else tuple(sorted(namespaces.items())))
|
|
if path[-1:] == "/":
|
|
path = path + "*" # implicit all (FIXME: keep this?)
|
|
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
|
|
# execute selector pattern
|
|
result = [elem]
|
|
context = _SelectorContext(elem)
|
|
for select in selector:
|
|
result = select(context, result)
|
|
return result
|
|
|
|
##
|
|
# Find first matching object.
|
|
|
|
def find(elem, path, namespaces=None):
|
|
return next(iterfind(elem, path, namespaces), None)
|
|
|
|
##
|
|
# Find all matching objects.
|
|
|
|
def findall(elem, path, namespaces=None):
|
|
return list(iterfind(elem, path, namespaces))
|
|
|
|
##
|
|
# Find text for first matching object.
|
|
|
|
def findtext(elem, path, default=None, namespaces=None):
|
|
try:
|
|
elem = next(iterfind(elem, path, namespaces))
|
|
return elem.text or ""
|
|
except StopIteration:
|
|
return default
|