filterx/filterx-scope: don't move the variables array multiple times

Optimize the removal of multiple elements.

Signed-off-by: Balazs Scheidler <[email protected]>

lib/filterx/filterx-scope.c

@@ -377,16 +377,31 @@ filterx_scope_invalidate_log_msg_cache(FilterXScope *self)
 {
   g_assert(filterx_scope_has_log_msg_changes(self));
 
-  gint i = 0;
-  while (i < self->variables->len)
+  /* this is a bit hacky and the solution would be to get rid of the GArray
+   * wrapper.  GArray does not allow us to remove multiple elements in a
+   * single loop, without moving the array multiple times.  So we basically
+   * open code this instead of multiple calls to g_array_remove_index()
+   */
+
+  gint src_index, dst_index;
+  for (src_index = 0, dst_index = 0; src_index < self->variables->len; src_index++)
     {
-      FilterXVariable *v = &g_array_index(self->variables, FilterXVariable, i);
+      FilterXVariable *v = &g_array_index(self->variables, FilterXVariable, src_index);
 
       if (!filterx_variable_is_floating(v) && self->syncable)
-        g_array_remove_index(self->variables, i);
+        {
+          /* skip this variable */
+          filterx_variable_free(v);
+        }
       else
-        i++;
+        {
+          if (src_index != dst_index)
+            g_array_index(self->variables, FilterXVariable, dst_index) = g_array_index(self->variables, FilterXVariable, src_index);
+          dst_index++;
+        }
     }
+  /* and this is the HACK: we reset the "len" member by poking that inside the GArray data structure */
+  self->variables->len = dst_index;
 
   filterx_scope_clear_log_msg_has_changes(self);
 }