| # |
| # 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) |