199 lines
5.9 KiB
Python
199 lines
5.9 KiB
Python
![]() |
#
|
||
|
# 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)
|