Add rollback queue, like commit queue.

etiquette/objects.py

@@ -1033,16 +1033,22 @@ class Photo(ObjectBase):
 
         if new_path.normcase == old_path.normcase:
             # If they are equivalent but differently cased, just rename.
-            action = os.rename
-            args = [old_path.absolute_path, new_path.absolute_path]
+            self.photodb.on_commit_queue.append({
+                'action': os.rename,
+                'args': [old_path.absolute_path, new_path.absolute_path],
+            })
         else:
             # Delete the original, leaving only the new copy / hardlink.
-            action = os.remove
-            args = [old_path.absolute_path]
+            self.photodb.on_commit_queue.append({
+                'action': os.remove,
+                'args': [old_path.absolute_path],
+            })
+            self.photodb.on_rollback_queue.append({
+                'action': os.remove,
+                'args': [new_path.absolute_path],
+            })
 
         self._uncache()
-        queue_action = {'action': action, 'args': args}
-        self.photodb.on_commit_queue.append(queue_action)
 
         self.__reinit__()
 

etiquette/photodb.py

@@ -671,6 +671,7 @@ class PDBSQLMixin:
     def __init__(self):
         super().__init__()
         self.on_commit_queue = []
+        self.on_rollback_queue = []
         self.savepoints = []
 
     def assert_table_exists(self, table):
@@ -689,6 +690,7 @@ class PDBSQLMixin:
             args = task.get('args', [])
             kwargs = task.get('kwargs', {})
             task['action'](*args, **kwargs)
+
         self.savepoints.clear()
         self.sql.commit()
 
@@ -739,6 +741,17 @@ class PDBSQLMixin:
             self.log.debug('Nothing to roll back.')
             return
 
+        while len(self.on_rollback_queue) > 0:
+            task = self.on_rollback_queue.pop(-1)
+            if task == savepoint:
+                break
+            if isinstance(task, str):
+                # Intermediate savepoints.
+                continue
+            args = task.get('args', [])
+            kwargs = task.get('kwargs', {})
+            task['action'](*args, **kwargs)
+
         if savepoint is not None:
             self.log.debug('Rolling back to %s', savepoint)
             self.sql_execute(f'ROLLBACK TO "{savepoint}"')
@@ -761,6 +774,7 @@ class PDBSQLMixin:
         self.sql.execute(query)
         self.savepoints.append(savepoint_id)
         self.on_commit_queue.append(savepoint_id)
+        self.on_rollback_queue.append(savepoint_id)
         return savepoint_id
 
     def sql_delete(self, table, pairs):