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Diffstat (limited to 'lib/python2.7/xml/etree/ElementPath.py')
-rw-r--r-- | lib/python2.7/xml/etree/ElementPath.py | 303 |
1 files changed, 303 insertions, 0 deletions
diff --git a/lib/python2.7/xml/etree/ElementPath.py b/lib/python2.7/xml/etree/ElementPath.py new file mode 100644 index 0000000..4a626d7 --- /dev/null +++ b/lib/python2.7/xml/etree/ElementPath.py @@ -0,0 +1,303 @@ +# +# 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( + "(" + "'[^']*'|\"[^\"]*\"|" + "::|" + "//?|" + "\.\.|" + "\(\)|" + "[/.*:\[\]\(\)@=])|" + "((?:\{[^}]+\})?[^/\[\]\(\)@=\s]+)|" + "\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) + 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: + for e in elem: + yield e + return select + +def prepare_self(next, token): + def select(context, result): + for elem in result: + yield elem + return select + +def prepare_descendant(next, token): + token = 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.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: + token = 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]) + 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("\d+$", predicate[0]): + # [tag] + tag = predicate[0] + def select(context, result): + for elem in result: + if elem.find(tag) is not None: + yield elem + return select + if signature == "-='" and not re.match("\d+$", predicate[0]): + # [tag='value'] + tag = predicate[0] + value = predicate[-1] + def select(context, result): + for elem in result: + for e in elem.findall(tag): + if "".join(e.itertext()) == 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 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") + next = iter(xpath_tokenizer(path, namespaces)).next + token = next() + selector = [] + while 1: + try: + selector.append(ops[token[0]](next, token)) + except StopIteration: + raise SyntaxError("invalid path") + try: + token = next() + if token[0] == "/": + token = next() + except StopIteration: + break + _cache[path] = 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): + try: + return iterfind(elem, path, namespaces).next() + except StopIteration: + return 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 = iterfind(elem, path, namespaces).next() + return elem.text or "" + except StopIteration: + return default |