Current search function in tp-logger searches over all the logs (all accounts, all users).

void tpl_log_manager_search_async (TplLogManager *manager,
    const gchar *text,
    gint type_mask,
    GAsyncReadyCallback callback,
    gpointer user_data);

Last function maybe in useful in some use cases, but overkill in others. For example when we are just searching in the logs of a given contact. For that case something much more optimal like the following would be useful.

void tpl_log_manager_search_by_entity_async (
    TplLogManager *manager,
    TpAccount *account,
    TplEntity *target,
    const gchar *text,
    gint type_mask,
    GAsyncReadyCallback callback,
    gpointer user_data);

So only the logs of the given contact (identified with the account and entity) will be searched in.