XML datastore: load will now automatically try to load backup

nemubot/datastore/xml.py

@@ -15,11 +15,14 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import fcntl
+import logging
 import os
 import xml.parsers.expat
 
 from nemubot.datastore.abstract import Abstract
 
+logger = logging.getLogger("nemubot.datastore.xml")
+
 
 class XML(Abstract):
 
@@ -88,10 +91,27 @@ class XML(Abstract):
         """
 
         data_file = self._get_data_file_path(module)
+
+        # Try to load original file
         if os.path.isfile(data_file):
             from nemubot.tools.xmlparser import parse_file
+            try:
                 return parse_file(data_file)
-        else:
+            except xml.parsers.expat.ExpatError:
+                # Try to load from backup
+                for i in range(10):
+                    path = data_file + "." + str(i)
+                    if os.path.isfile(path):
+                        try:
+                            cnt = parse_file(path)
+
+                            logger.warn("Restoring from backup: %s", path)
+
+                            return cnt
+                        except xml.parsers.expat.ExpatError:
+                            continue
+
+        # Default case: initialize a new empty datastore
         return Abstract.load(self, module)
 
     def _rotate(self, path):