Make get_subscribed_rooms work even for non-persistant rooms

This will store info about non-persistant rooms in db, but rooms with that
that option enabled will not be restored on server restart.

This will save info about room only on subscribers change.

src/mod_muc.erl

@@ -654,31 +654,46 @@ load_permanent_rooms(Host, ServerHost, Access,
 		     HistorySize, RoomShaper, QueueType) ->
     RMod = gen_mod:ram_db_mod(ServerHost, ?MODULE),
     lists:foreach(
-      fun(R) ->
-		{Room, Host} = R#muc_room.name_host,
-	      case RMod:find_online_room(ServerHost, Room, Host) of
-		  error ->
-			{ok, Pid} = mod_muc_room:start(Host,
-				ServerHost, Access, Room,
-				HistorySize, RoomShaper,
-				R#muc_room.opts, QueueType),
-		      RMod:register_online_room(ServerHost, Room, Host, Pid);
-		  {ok, _} ->
-		      ok
-		end
-	end,
-	get_rooms(ServerHost, Host)).
+	fun(R) ->
+	    {Room, Host} = R#muc_room.name_host,
+	    case proplists:get_bool(persistent, R#muc_room.opts) of
+		true ->
+		    case RMod:find_online_room(ServerHost, Room, Host) of
+			error ->
+			    {ok, Pid} = mod_muc_room:start(Host,
+							   ServerHost, Access, Room,
+							   HistorySize, RoomShaper,
+							   R#muc_room.opts, QueueType),
+			    RMod:register_online_room(ServerHost, Room, Host, Pid);
+			{ok, _} ->
+			    ok
+		    end;
+		_ ->
+		    forget_room(ServerHost, Host, Room)
+	    end
+	end, get_rooms(ServerHost, Host)).
 
 start_new_room(Host, ServerHost, Access, Room,
 	    HistorySize, RoomShaper, From,
 	    Nick, DefRoomOpts, QueueType) ->
-    case restore_room(ServerHost, Host, Room) of
+    Opts = case restore_room(ServerHost, Host, Room) of
+	       error ->
+		   error;
+	       Opts0 ->
+		   case proplists:get_bool(persistent, Opts0) of
+		       true ->
+			   Opts0;
+		       _ ->
+			   error
+		   end
+	   end,
+    case Opts of
 	error ->
 	    ?DEBUG("MUC: open new room '~s'~n", [Room]),
 	    mod_muc_room:start(Host, ServerHost, Access, Room,
 		HistorySize, RoomShaper,
 		From, Nick, DefRoomOpts, QueueType);
-	Opts ->
+	_ ->
 	    ?DEBUG("MUC: restore room '~s'~n", [Room]),
 	    mod_muc_room:start(Host, ServerHost, Access, Room,
 		HistorySize, RoomShaper, Opts, QueueType)

src/mod_muc_room.erl

@@ -1140,6 +1140,7 @@ close_room_if_temporary_and_empty(StateData1) ->
 		    "and empty",
 		    [jid:encode(StateData1#state.jid)]),
 	  add_to_log(room_existence, destroyed, StateData1),
+	  maybe_forget_room(StateData1),
 	  {stop, normal, StateData1};
       _ -> {next_state, normal_state, StateData1}
     end.
@@ -3485,14 +3486,15 @@ change_config(Config, StateData) ->
                 end,
                 store_room(StateData1),
                 StateData1;
-            {true, false} ->
-                Affiliations = get_affiliations(StateData),
-                mod_muc:forget_room(StateData1#state.server_host,
-                                    StateData1#state.host,
-                                    StateData1#state.room),
-                StateData1#state{affiliations = Affiliations};
-            {false, false} ->
-                StateData1
+            {WasPersistent, false} ->
+		maybe_forget_room(StateData1),
+		case WasPersistent of
+		    true ->
+			Affiliations = get_affiliations(StateData),
+			StateData1#state{affiliations = Affiliations};
+		    _ ->
+			StateData1
+		end
         end,
     case {(StateData#state.config)#config.members_only,
 	  Config#config.members_only} of
@@ -3822,14 +3824,27 @@ destroy_room(DEl, StateData) ->
 			   Info#user.jid, Packet,
 			   ?NS_MUCSUB_NODES_CONFIG, StateData)
       end, ok, get_users_and_subscribers(StateData)),
-    case (StateData#state.config)#config.persistent of
-      true ->
-	  mod_muc:forget_room(StateData#state.server_host,
-			      StateData#state.host, StateData#state.room);
-      false -> ok
-    end,
+    maybe_forget_room(StateData),
     {result, undefined, stop}.
 
+maybe_forget_room(StateData) ->
+    Forget = case (StateData#state.config)#config.persistent of
+		 true ->
+		     true;
+		 _ ->
+		     Mod = gen_mod:db_mod(StateData#state.server_host, mod_muc),
+		     erlang:function_exported(Mod, get_subscribed_rooms, 3)
+	     end,
+    case Forget of
+	true ->
+	    mod_muc:forget_room(StateData#state.server_host,
+				StateData#state.host,
+				StateData#state.room),
+	    StateData;
+	_ ->
+	    StateData
+    end.
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % Disco
 
@@ -4359,7 +4374,20 @@ element_size(El) ->
 store_room(StateData) ->
     store_room(StateData, []).
 store_room(StateData, ChangesHints) ->
-    if (StateData#state.config)#config.persistent ->
+    % Let store persistent rooms or on those backends that have get_subscribed_rooms
+    ShouldStore = case (StateData#state.config)#config.persistent of
+		      true ->
+			  true;
+		      _ ->
+			  case ChangesHints of
+			      [] ->
+				  false;
+			      _ ->
+				  Mod = gen_mod:db_mod(StateData#state.server_host, mod_muc),
+				  erlang:function_exported(Mod, get_subscribed_rooms, 3)
+			  end
+		  end,
+    if ShouldStore ->
 	    mod_muc:store_room(StateData#state.server_host,
 			       StateData#state.host, StateData#state.room,
 			       make_opts(StateData),