text: #include <crea/chain/transaction_object.hpp>
  
  namespace crea { namespace chain {
  
  const object* transaction_index::create(const std::function<void (object*)>& constructor, object_id_type)
  {
     transaction_object obj;
  
     obj.id = get_next_available_id();
     constructor(&obj);
  
     auto result = _index.insert(std::move(obj));
     FC_ASSERT(result.second, "Could not create transaction_object! Most likely a uniqueness constraint is violated.");
     return &*result.first;
  }
  
  void transaction_index::modify(const object* obj,
                                 const std::function<void (object*)>& m)
  {
     assert(obj != nullptr);
     FC_ASSERT(obj->id < _index.size());
  
     const transaction_object* t = dynamic_cast<const transaction_object*>(obj);
     assert(t != nullptr);
  
     auto itr = _index.find(obj->id.instance());
     assert(itr != _index.end());
     _index.modify(itr, [&m](transaction_object& o) { m(&o); });
  }
  
  void transaction_index::add(unique_ptr<object> o)
  {
     assert(o);
     object_id_type id = o->id;
     assert(id.space() == transaction_object::space_id);
     assert(id.type() == transaction_object::type_id);
     assert(id.instance() == size());
  
     auto trx = dynamic_cast<transaction_object*>(o.get());
     assert(trx != nullptr);
     o.release();
  
     auto result = _index.insert(std::move(*trx));
     FC_ASSERT(result.second, "Could not insert transaction_object! Most likely a uniqueness constraint is violated.");
  }
  
  void transaction_index::remove(object_id_type id)
  {
     auto& index = _index.get<instance>();
     auto itr = index.find(id.instance());
     if( itr == index.end() )
        return;
  
     assert(id.space() == transaction_object::space_id);
     assert(id.type() == transaction_object::type_id);
  
     index.erase(itr);
  }
  
  const object*transaction_index::get(object_id_type id) const
  {
     if( id.type() != transaction_object::type_id ||
         id.space() != transaction_object::space_id )
        return nullptr;
  
     auto itr = _index.find(id.instance());
     if( itr == _index.end() )
        return nullptr;
     return &*itr;
  }
  
  } } // crea::chain
  