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Diffstat (limited to 'Lib/xml/etree/ElementPath.py')
| -rw-r--r-- | Lib/xml/etree/ElementPath.py | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/Lib/xml/etree/ElementPath.py b/Lib/xml/etree/ElementPath.py new file mode 100644 index 0000000..00dbe9d --- /dev/null +++ b/Lib/xml/etree/ElementPath.py @@ -0,0 +1,198 @@ +# +# ElementTree +# $Id: ElementPath.py 1858 2004-06-17 21:31:41Z 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 +# +# Copyright (c) 2003-2004 by Fredrik Lundh. All rights reserved. +# +# fredrik@pythonware.com +# http://www.pythonware.com +# +# -------------------------------------------------------------------- +# The ElementTree toolkit is +# +# Copyright (c) 1999-2004 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/2.4/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.compile( + "(::|\.\.|\(\)|[/.*:\[\]\(\)@=])|((?:\{[^}]+\})?[^/:\[\]\(\)@=\s]+)|\s+" + ).findall + +class xpath_descendant_or_self: + pass + +## +# Wrapper for a compiled XPath. + +class Path: + + ## + # Create an Path instance from an XPath expression. + + def __init__(self, path): + tokens = xpath_tokenizer(path) + # the current version supports 'path/path'-style expressions only + self.path = [] + self.tag = None + if tokens and tokens[0][0] == "/": + raise SyntaxError("cannot use absolute path on element") + while tokens: + op, tag = tokens.pop(0) + if tag or op == "*": + self.path.append(tag or op) + elif op == ".": + pass + elif op == "/": + self.path.append(xpath_descendant_or_self()) + continue + else: + raise SyntaxError("unsupported path syntax (%s)" % op) + if tokens: + op, tag = tokens.pop(0) + if op != "/": + raise SyntaxError( + "expected path separator (%s)" % (op or tag) + ) + if self.path and isinstance(self.path[-1], xpath_descendant_or_self): + raise SyntaxError("path cannot end with //") + if len(self.path) == 1 and isinstance(self.path[0], type("")): + self.tag = self.path[0] + + ## + # Find first matching object. + + def find(self, element): + tag = self.tag + if tag is None: + nodeset = self.findall(element) + if not nodeset: + return None + return nodeset[0] + for elem in element: + if elem.tag == tag: + return elem + return None + + ## + # Find text for first matching object. + + def findtext(self, element, default=None): + tag = self.tag + if tag is None: + nodeset = self.findall(element) + if not nodeset: + return default + return nodeset[0].text or "" + for elem in element: + if elem.tag == tag: + return elem.text or "" + return default + + ## + # Find all matching objects. + + def findall(self, element): + nodeset = [element] + index = 0 + while 1: + try: + path = self.path[index] + index = index + 1 + except IndexError: + return nodeset + set = [] + if isinstance(path, xpath_descendant_or_self): + try: + tag = self.path[index] + if not isinstance(tag, type("")): + tag = None + else: + index = index + 1 + except IndexError: + tag = None # invalid path + for node in nodeset: + new = list(node.getiterator(tag)) + if new and new[0] is node: + set.extend(new[1:]) + else: + set.extend(new) + else: + for node in nodeset: + for node in node: + if path == "*" or node.tag == path: + set.append(node) + if not set: + return [] + nodeset = set + +_cache = {} + +## +# (Internal) Compile path. + +def _compile(path): + p = _cache.get(path) + if p is not None: + return p + p = Path(path) + if len(_cache) >= 100: + _cache.clear() + _cache[path] = p + return p + +## +# Find first matching object. + +def find(element, path): + return _compile(path).find(element) + +## +# Find text for first matching object. + +def findtext(element, path, default=None): + return _compile(path).findtext(element, default) + +## +# Find all matching objects. + +def findall(element, path): + return _compile(path).findall(element) |