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+# -*- coding: utf-8 -*-
+#
+# Copyright (c) 2020 Martin Owens <doctormo@gmail.com>
+# Sergei Izmailov <sergei.a.izmailov@gmail.com>
+# Thomas Holder <thomas.holder@schrodinger.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+
+"""Utilities for parsing SVG documents.
+
+.. versionadded:: 1.2
+ Separated out from :py:mod:`inkex.elements._base`"""
+
+from collections import defaultdict
+from typing import DefaultDict, List, Any, Type
+
+from lxml import etree
+
+from ..interfaces.IElement import IBaseElement
+
+from ._utils import splitNS
+from ..utils import errormsg
+from ..localization import inkex_gettext as _
+
+
+class NodeBasedLookup(etree.PythonElementClassLookup):
+ """
+ We choose what kind of Elements we should return for each element, providing useful
+ SVG based API to our extensions system.
+ """
+
+ default: Type[IBaseElement]
+
+ # (ns,tag) -> list(cls) ; ascending priority
+ lookup_table = defaultdict(list) # type: DefaultDict[str, List[Any]]
+
+ @classmethod
+ def register_class(cls, klass):
+ """Register the given class using it's attached tag name"""
+ cls.lookup_table[splitNS(klass.tag_name)].append(klass)
+
+ @classmethod
+ def find_class(cls, xpath):
+ """Find the class for this type of element defined by an xpath
+
+ .. versionadded:: 1.1"""
+ if isinstance(xpath, type):
+ return xpath
+ for kls in cls.lookup_table[splitNS(xpath.split("/")[-1])]:
+ # TODO: We could create a apply the xpath attrs to the test element
+ # to narrow the search, but this does everything we need right now.
+ test_element = kls()
+ if kls.is_class_element(test_element):
+ return kls
+ raise KeyError(f"Could not find svg tag for '{xpath}'")
+
+ def lookup(self, doc, element): # pylint: disable=unused-argument
+ """Lookup called by lxml when assigning elements their object class"""
+ try:
+ for kls in reversed(self.lookup_table[splitNS(element.tag)]):
+ if kls.is_class_element(element): # pylint: disable=protected-access
+ return kls
+ except TypeError:
+ # Handle non-element proxies case
+ # The documentation implies that it's not possible
+ # Didn't found a reliable way to check whether proxy corresponds to element
+ # or not
+ # Look like lxml issue to me.
+ # The troubling element is "<!--Comment-->"
+ return None
+ return NodeBasedLookup.default
+
+
+SVG_PARSER = etree.XMLParser(huge_tree=True, strip_cdata=False, recover=True)
+SVG_PARSER.set_element_class_lookup(NodeBasedLookup())
+
+
+def load_svg(stream):
+ """Load SVG file using the SVG_PARSER"""
+ if (isinstance(stream, str) and stream.lstrip().startswith("<")) or (
+ isinstance(stream, bytes) and stream.lstrip().startswith(b"<")
+ ):
+ parsed = etree.ElementTree(etree.fromstring(stream, parser=SVG_PARSER))
+ else:
+ parsed = etree.parse(stream, parser=SVG_PARSER)
+ if len(SVG_PARSER.error_log) > 0:
+ errormsg(
+ _(
+ "A parsing error occured, which means you are likely working with "
+ "a non-conformant SVG file. The following errors were found:\n"
+ )
+ )
+ for __, element in enumerate(SVG_PARSER.error_log):
+ errormsg(
+ _("{}. Line {}, column {}").format(
+ element.message, element.line, element.column
+ )
+ )
+ errormsg(
+ _(
+ "\nProcessing will continue; however we encourage you to fix your"
+ " file manually."
+ )
+ )
+ return parsed