debug-viewer: Ignore broken utf8 errors

Not much we can do if the input file is not perfectly valid UTF8
but we should just do as good as we can.

debug-viewer/GstDebugViewer/Data.py

@@ -344,7 +344,7 @@ class LineCache (Producer):
                 yield True
 
             offset = tell()
-            line = readline().decode('utf-8')
+            line = readline().decode('utf-8', errors='replace')
             if not line:
                 break
             match = rexp_match(line)
@@ -384,7 +384,7 @@ class LogLine (list):
 
     @classmethod
     def parse_full(cls, line_string):
-        match = cls._line_regex.match(line_string.decode('utf8'))
+        match = cls._line_regex.match(line_string.decode('utf8', errors='replace'))
         if match is None:
             # raise ValueError ("not a valid log line (%r)" % (line_string,))
             groups = [0, 0, 0, 0, "", "", 0, "", "", 0]

debug-viewer/GstDebugViewer/GUI/columns.py

@@ -346,7 +346,7 @@ class MessageColumn (TextColumn):
 
         def message_data_func(column, cell, model, tree_iter, user_data):
 
-            msg = model.get_value(tree_iter, id_).decode("utf8")
+            msg = model.get_value(tree_iter, id_).decode("utf8", errors="replace")
 
             if not highlighters:
                 cell.props.text = msg

debug-viewer/GstDebugViewer/GUI/window.py

@@ -690,7 +690,7 @@ class Window (object):
         line_text = model.access_offset(line_offset).strip()
         line_text = Data.strip_escape(line_text)
 
-        self.clipboard.set_text(line_text.decode('utf8'), -1)
+        self.clipboard.set_text(line_text.decode('utf8', errors='replace'), -1)
 
     @action
     def handle_edit_copy_message_action_activate(self, action):