a beginning

Signed-off-by: Christian Henkel <[email protected]>

src/as2fm/as2fm_common/logging.py

@@ -0,0 +1,68 @@
+# Copyright (c) 2024 - for information on the respective copyright owner
+# see the NOTICE file
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+Modules that help produce better error messages.
+"""
+
+import xml.etree.ElementTree as ET
+
+
+class InformativeParser(ET.XMLParser):
+    """
+    An extension to the ElementTree parser that stores the line number of each element.
+    This will be used to provide more informative error messages.
+    """
+
+    def _start_list(self, *args, **kwargs):
+        element = super(InformativeParser, self)._start_list(*args, **kwargs)
+        element._file_name = self.parser._file_name  # pylint: disable=protected-access
+        element._start_line_number = \
+            self.parser.CurrentLineNumber  # pylint: disable=protected-access
+        element._start_column_number = \
+            self.parser.CurrentColumnNumber  # pylint: disable=protected-access
+        element._start_byte_index = \
+            self.parser.CurrentByteIndex  # pylint: disable=protected-access
+        return element
+
+    def _end(self, *args, **kwargs):
+        element = super(InformativeParser, self)._end(*args, **kwargs)
+        element._end_line_number = \
+            self.parser.CurrentLineNumber  # pylint: disable=protected-access
+        element._end_column_number = \
+            self.parser.CurrentColumnNumber  # pylint: disable=protected-access
+        element._end_byte_index = \
+            self.parser.CurrentByteIndex  # pylint: disable=protected-access
+        return element
+
+
+def error(element: ET.Element, message: str) -> str:
+    """
+    Produce an error message with the line number of the element.
+
+    :param element: The element that caused the error
+    :param message: The error message
+    :return: The error message with the line number
+    """
+    assert hasattr(element, '_file_name'), \
+        'The element must have the attribute "_file_name" '\
+        '(set by `as2fm_common.logging.InformativeParser`)'
+    assert hasattr(element, '_start_line_number'), \
+        'The element must have the attribute "_start_line_number" '\
+        '(set by `as2fm_common.logging.InformativeParser`)'
+    return (
+        f'E ({element._file_name}:'  # pylint: disable=protected-access
+        + f'{element._start_line_number}) '  # pylint: disable=protected-access
+        + f'{message}')