cpython/Lib/xml/etree/ElementInclude.py

144 lines
5.0 KiB
Python

#
# ElementTree
# $Id: ElementInclude.py 3375 2008-02-13 08:05:08Z fredrik $
#
# limited xinclude support for element trees
#
# history:
# 2003-08-15 fl created
# 2003-11-14 fl fixed default loader
#
# Copyright (c) 2003-2004 by Fredrik Lundh. All rights reserved.
#
# fredrik@pythonware.com
# http://www.pythonware.com
#
# --------------------------------------------------------------------
# The ElementTree toolkit is
#
# Copyright (c) 1999-2008 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.
##
# Limited XInclude support for the ElementTree package.
##
import copy
from . import ElementTree
XINCLUDE = "{http://www.w3.org/2001/XInclude}"
XINCLUDE_INCLUDE = XINCLUDE + "include"
XINCLUDE_FALLBACK = XINCLUDE + "fallback"
##
# Fatal include error.
class FatalIncludeError(SyntaxError):
pass
##
# Default loader. This loader reads an included resource from disk.
#
# @param href Resource reference.
# @param parse Parse mode. Either "xml" or "text".
# @param encoding Optional text encoding (UTF-8 by default for "text").
# @return The expanded resource. If the parse mode is "xml", this
# is an ElementTree instance. If the parse mode is "text", this
# is a Unicode string. If the loader fails, it can return None
# or raise an OSError exception.
# @throws OSError If the loader fails to load the resource.
def default_loader(href, parse, encoding=None):
if parse == "xml":
with open(href, 'rb') as file:
data = ElementTree.parse(file).getroot()
else:
if not encoding:
encoding = 'UTF-8'
with open(href, 'r', encoding=encoding) as file:
data = file.read()
return data
##
# Expand XInclude directives.
#
# @param elem Root element.
# @param loader Optional resource loader. If omitted, it defaults
# to {@link default_loader}. If given, it should be a callable
# that implements the same interface as <b>default_loader</b>.
# @throws FatalIncludeError If the function fails to include a given
# resource, or if the tree contains malformed XInclude elements.
# @throws OSError If the function fails to load a given resource.
def include(elem, loader=None):
if loader is None:
loader = default_loader
# look for xinclude elements
i = 0
while i < len(elem):
e = elem[i]
if e.tag == XINCLUDE_INCLUDE:
# process xinclude directive
href = e.get("href")
parse = e.get("parse", "xml")
if parse == "xml":
node = loader(href, parse)
if node is None:
raise FatalIncludeError(
"cannot load %r as %r" % (href, parse)
)
node = copy.copy(node)
if e.tail:
node.tail = (node.tail or "") + e.tail
elem[i] = node
elif parse == "text":
text = loader(href, parse, e.get("encoding"))
if text is None:
raise FatalIncludeError(
"cannot load %r as %r" % (href, parse)
)
if i:
node = elem[i-1]
node.tail = (node.tail or "") + text + (e.tail or "")
else:
elem.text = (elem.text or "") + text + (e.tail or "")
del elem[i]
continue
else:
raise FatalIncludeError(
"unknown parse type in xi:include tag (%r)" % parse
)
elif e.tag == XINCLUDE_FALLBACK:
raise FatalIncludeError(
"xi:fallback tag must be child of xi:include (%r)" % e.tag
)
else:
include(e, loader)
i = i + 1