Method on_objects_changed

libraries/app/database_api.cpp:1484–1537

}

void database_api_impl::on_objects_changed(const vector<object_id_type>& ids)
{
   vector<variant>    updates;
   map< pair<asset_id_type, asset_id_type>,  vector<variant> > market_broadcast_queue;

   for(auto id : ids)
   {
      const object* obj = nullptr;
      if( _subscribe_callback )
      {
         obj = _db.find_object( id );
         if( obj )
         {
            updates.emplace_back( obj->to_variant() );
         }
         else
         {
            updates.emplace_back(id); // send just the id to indicate removal
         }
      }

      if( _market_subscriptions.size() )
      {
         if( !_subscribe_callback ) 
            obj = _db.find_object( id );
         if( obj )
         {
            const limit_order_object* order = dynamic_cast<const limit_order_object*>(obj);
            if( order )
            {
               auto sub = _market_subscriptions.find( order->get_market() );
               if( sub != _market_subscriptions.end() )
                  market_broadcast_queue[order->get_market()].emplace_back( order->id );
            }
         }
      }
   }

   auto capture_this = shared_from_this();

   /// pushing the future back / popping the prior future if it is complete.
   /// if a connection hangs then this could get backed up and result in
   /// a failure to exit cleanly.
   fc::async([capture_this,this,updates,market_broadcast_queue](){
      if( _subscribe_callback ) _subscribe_callback( updates );

      for( const auto& item : market_broadcast_queue )
      {
        auto sub = _market_subscriptions.find(item.first);
        if( sub != _market_subscriptions.end() )
            sub->second( fc::variant(item.second ) );
      }
   });
}

/** note: this method cannot yield because it is called in the middle of
 * apply a block.