[Fix] Allow to set 0 as number of rows to disable roll history

Issue: #4947
Closes: #4947

src/controller.c

 
 	L = ctx->cfg->lua_state;
 
-	if (!ctx->srv->history->disabled) {
+	if (ctx->srv->history && !ctx->srv->history->disabled) {
 		rspamd_controller_handle_legacy_history(session, ctx, conn_ent, msg);
 	}
 	else {
 		return 0;
 	}
 
-	if (!ctx->srv->history->disabled) {
+	if (ctx->srv->history && !ctx->srv->history->disabled) {
 		/* Clean from start to the current row */
 		completed_rows = g_atomic_int_get(&ctx->srv->history->cur_row);
 

src/libserver/protocol.c

 	}
 
 	if (!(task->flags & RSPAMD_TASK_FLAG_NO_LOG)) {
-		rspamd_roll_history_update(task->worker->srv->history, task);
+		if (task->worker->srv->history) {
+			rspamd_roll_history_update(task->worker->srv->history, task);
+		}
 	}
 	else {
 		msg_debug_protocol("skip history update due to no log flag");

src/rspamd.c

 
 	/* Create rolling history */
 	rspamd_main->history = rspamd_roll_history_new(rspamd_main->server_pool,
-												   rspamd_main->cfg->history_rows, rspamd_main->cfg);
+												   rspamd_main->cfg->history_rows,
+												   rspamd_main->cfg);
 
 	msg_info_main("rspamd " RVERSION
 				  " is starting, build id: " RID);
 	}
 
 	/* Maybe read roll history */
-	if (rspamd_main->cfg->history_file) {
+	if (rspamd_main->history && rspamd_main->cfg->history_file) {
 		rspamd_roll_history_load(rspamd_main->history,
 								 rspamd_main->cfg->history_file);
 	}
 	ev_loop(event_loop, 0);
 
 	/* Maybe save roll history */
-	if (rspamd_main->cfg->history_file) {
+	if (rspamd_main->history && rspamd_main->cfg->history_file) {
 		rspamd_roll_history_save(rspamd_main->history,
 								 rspamd_main->cfg->history_file);
 	}