develop.md

Develop

New object check list

This walk-through will cover adding new object to DEIP protocol. We will use example test_object with following structure:

# Pseudocode
test_object {
    id id;
    string name;
}

• in libraries\chain\include\deip\chain\deip_object_types.hpp:

  • add test_object_type to object_type enum
  • introduce test_object class
  • define oid<test_object> test_id_type test object id type
  • reflect test_object_type field in FC_REFLECT_ENUM

• add libraries\chain\include\deip\chain\test_object.hpp and implement test_object class:

    namespace deip {
    namespace chain {
    
    using deip::protocol::asset;
    
    class test_object : public object<test_object_type, test_object>
    {
        test_object() = delete;
    
    public:
    
        template <typename Constructor, typename Allocator>
        test_object(Constructor&& c, allocator<Allocator> a)
        {
            c(*this);
        }
    
        id_type id;
        fc::shared_string name;
    };
    
    struct by_name;
    
    typedef multi_index_container<test_object,
            indexed_by<ordered_unique<tag<by_id>,
                    member<test_object,
                            test_id_type,
                            &test_object::id>>,
                    ordered_unique<tag<by_name>,
                            member<test_object,
                                    fc::shared_string,
                                    &test_object::name>>>,
            allocator<test_object>>
            test_index;
    }
    }
    
    FC_REFLECT( deip::chain::test_object,
                (id)(name)
    )
    
    CHAINBASE_SET_INDEX_TYPE( deip::chain::test_object, deip::chain::test_index )
  

Important: test_object class will not compile and will have a lot of errors until you reference it from another .cpp/.hpp file

• add libraries\chain\include\deip\chain\dbs_test.hpp:

    namespace deip {
    namespace chain {
    
    ///** DB service for operations with discipline_object
    // *  --------------------------------------------
    // */
    class dbs_test : public dbs_base {
        friend class dbservice_dbs_factory;
    
        dbs_test() = delete;
    
    protected:
        explicit dbs_test(database &db);
    
    public:
        using test_refs_type = std::vector<std::reference_wrapper<const test_object>>;
    
        /** Lists all tests.
        *
        * @returns a list of test objects
        */
        test_refs_type get_tests() const;
    
        /** Get test by id
        */
        const test_object& get_test(const test_id_type id) const;
    
        /** Get test by name
        */
        const test_object& get_test_by_name(const fc::shared_string& name) const;
    };
    } // namespace chain
    } // namespace deip
  

• add libraries\chain\dbs_test.cpp:

  • implement db service logic:

        #include <deip/chain/dbs_test.hpp>
        #include <deip/chain/database.hpp>
        
        #include <tuple>
        
        namespace deip {
        namespace chain {
        
        dbs_test::dbs_test(database &db)
            : _base_type(db)
        {
        }
        
        dbs_test::test_refs_type dbs_test::get_tests() const
        {
            test_refs_type ret;
        
            auto idx = db_impl().get_index<test_index>().indicies();
            auto it = idx.cbegin();
            const auto it_end = idx.cend();
            while (it != it_end)
            {
                ret.push_back(std::cref(*it));
                ++it;
            }
        
            return ret;
        }
        
        const test_object& dbs_test::get_test(const test_id_type id) const
        {
            return db_impl().get<test_object>(id);
        }
        
        const test_object& dbs_test::get_test_by_name(const fc::shared_string & name) const
        {
            return db_impl().get<test_object, by_name>(name);
        }
        
        } //namespace chain
        } //namespace deip
    

  • add dbs_test.cpp to libraries\chain\CMakeLists.txt and reload CMake project so dbs_test.cpp is included in build target

At this stage you should have fully working test_object and corresponding types and dbs_type which is database service for test_object

TODO: Implement API for test_object

TODO: Setup and configure node for private test net