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Diffstat (limited to 'Lib/xml/etree/ElementPath.py')
| -rw-r--r-- | Lib/xml/etree/ElementPath.py | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/Lib/xml/etree/ElementPath.py b/Lib/xml/etree/ElementPath.py new file mode 100644 index 0000000..e8093c6 --- /dev/null +++ b/Lib/xml/etree/ElementPath.py @@ -0,0 +1,196 @@ +#
+# 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.
+# --------------------------------------------------------------------
+
+##
+# 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)
+
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