1 files changed, 124 insertions, 0 deletions
diff --git a/share/extensions/inkex/tester/xmldiff.py b/share/extensions/inkex/tester/xmldiff.py
new file mode 100644
index 0000000..1864530
--- /dev/null
+++ b/share/extensions/inkex/tester/xmldiff.py
@@ -0,0 +1,124 @@
+#
+# Copyright 2011 (c) Ian Bicking <ianb@colorstudy.com>
+#           2019 (c) Martin Owens <doctormo@gmail.com>
+#
+# Taken from http://formencode.org under the GPL compatible PSF License.
+# Modified to produce more output as a diff.
+#
+"""
+Allow two xml files/lxml etrees to be compared, returning their differences.
+"""
+import xml.etree.ElementTree as xml
+from io import BytesIO
+
+from inkex.paths import Path
+
+
+def text_compare(test1, test2):
+    """
+    Compare two text strings while allowing for '*' to match
+    anything on either lhs or rhs.
+    """
+    if not test1 and not test2:
+        return True
+    if test1 == "*" or test2 == "*":
+        return True
+    return (test1 or "").strip() == (test2 or "").strip()
+
+
+class DeltaLogger(list):
+    """A record keeper of the delta between two svg files"""
+
+    def append_tag(self, tag_a, tag_b):
+        """Record a tag difference"""
+        if tag_a:
+            tag_a = f"<{tag_a}.../>"
+        if tag_b:
+            tag_b = f"<{tag_b}.../>"
+        self.append((tag_a, tag_b))
+
+    def append_attr(self, attr, value_a, value_b):
+        """Record an attribute difference"""
+
+        def _prep(val):
+            if val:
+                if attr == "d":
+                    return [attr] + Path(val).to_arrays()
+                return (attr, val)
+            return val
+
+        # Only append a difference if the preprocessed values are different.
+        # This solves the issue that -0 != 0 in path data.
+        prep_a = _prep(value_a)
+        prep_b = _prep(value_b)
+        if prep_a != prep_b:
+            self.append((prep_a, prep_b))
+
+    def append_text(self, text_a, text_b):
+        """Record a text difference"""
+        self.append((text_a, text_b))
+
+    def __bool__(self):
+        """Returns True if there's no log, i.e. the delta is clean"""
+        return not self.__len__()
+
+    __nonzero__ = __bool__
+
+    def __repr__(self):
+        if self:
+            return "No differences detected"
+        return f"{len(self)} xml differences"
+
+
+def to_xml(data):
+    """Convert string or bytes to xml parsed root node"""
+    if isinstance(data, str):
+        data = data.encode("utf8")
+    if isinstance(data, bytes):
+        return xml.parse(BytesIO(data)).getroot()
+    return data
+
+
+def xmldiff(data1, data2):
+    """Create an xml difference, will modify the first xml structure with a diff"""
+    xml1, xml2 = to_xml(data1), to_xml(data2)
+    delta = DeltaLogger()
+    _xmldiff(xml1, xml2, delta)
+    return xml.tostring(xml1).decode("utf-8"), delta
+
+
+def _xmldiff(xml1, xml2, delta):
+    if xml1.tag != xml2.tag:
+        xml1.tag = f"{xml1.tag}XXX{xml2.tag}"
+        delta.append_tag(xml1.tag, xml2.tag)
+    for name, value in xml1.attrib.items():
+        if name not in xml2.attrib:
+            delta.append_attr(name, xml1.attrib[name], None)
+            xml1.attrib[name] += "XXX"
+        elif xml2.attrib.get(name) != value:
+            delta.append_attr(name, xml1.attrib.get(name), xml2.attrib.get(name))
+            xml1.attrib[name] = f"{xml1.attrib.get(name)}XXX{xml2.attrib.get(name)}"
+    for name, value in xml2.attrib.items():
+        if name not in xml1.attrib:
+            delta.append_attr(name, None, value)
+            xml1.attrib[name] = "XXX" + value
+    if not text_compare(xml1.text, xml2.text):
+        delta.append_text(xml1.text, xml2.text)
+        xml1.text = f"{xml1.text}XXX{xml2.text}"
+    if not text_compare(xml1.tail, xml2.tail):
+        delta.append_text(xml1.tail, xml2.tail)
+        xml1.tail = f"{xml1.tail}XXX{xml2.tail}"
+
+    # Get children and pad with nulls
+    children_a = list(xml1)
+    children_b = list(xml2)
+    children_a += [None] * (len(children_b) - len(children_a))
+    children_b += [None] * (len(children_a) - len(children_b))
+
+    for child_a, child_b in zip(children_a, children_b):
+        if child_a is None:  # child_b exists
+            delta.append_tag(child_b.tag, None)
+        elif child_b is None:  # child_a exists
+            delta.append_tag(None, child_a.tag)
+        else:
+            _xmldiff(child_a, child_b, delta)