add get_top_markets

libraries/app/database_api.cpp

@@ -115,6 +115,7 @@ class database_api_impl : public std::enable_shared_from_this<database_api_impl>
       market_ticker                      get_ticker( const string& base, const string& quote, bool skip_order_book = false )const;
       market_volume                      get_24_volume( const string& base, const string& quote )const;
       order_book                         get_order_book( const string& base, const string& quote, unsigned limit = 50 )const;
+      vector<market_volume>              get_top_markets(uint limit)const;
       vector<market_trade>               get_trade_history( const string& base, const string& quote, fc::time_point_sec start, fc::time_point_sec stop, unsigned limit = 100 )const;
       vector<market_trade>               get_trade_history_by_sequence( const string& base, const string& quote, int64_t start, fc::time_point_sec stop, unsigned limit = 100 )const;
 
@@ -1292,6 +1293,40 @@ order_book database_api_impl::get_order_book( const string& base, const string&
    return result;
 }
 
+vector<market_volume> database_api::get_top_markets(uint limit)const
+{
+   return my->get_top_markets(limit);
+}
+
+vector<market_volume> database_api_impl::get_top_markets(uint limit)const
+{
+   FC_ASSERT( limit <= 100 );
+
+   const auto& volume_idx = _db.get_index_type<graphene::market_history::market_ticker_index>().indices().get<by_volume>();
+   auto itr = volume_idx.rbegin();
+   vector<market_volume> result;
+
+   fc::uint128 base_volume;
+   fc::uint128 quote_volume;
+
+   uint c = 0;
+   const fc::time_point_sec now = fc::time_point::now();
+
+   while( itr != volume_idx.rend() && result.size() < limit)
+   {
+      market_volume mv;
+      mv.time = now;
+      const auto assets = get_assets( { itr->base, itr->quote } );
+      mv.base = assets[0]->symbol;
+      mv.quote = assets[1]->symbol;
+      mv.base_volume = uint128_amount_to_string( itr->base_volume, assets[0]->precision );
+      mv.quote_volume = uint128_amount_to_string( itr->quote_volume, assets[1]->precision );
+      result.push_back(mv);
+      ++itr;
+   }
+   return result;
+}
+
 vector<market_trade> database_api::get_trade_history( const string& base,
                                                       const string& quote,
                                                       fc::time_point_sec start,

libraries/app/include/graphene/app/database_api.hpp

@@ -428,6 +428,13 @@ class database_api
        */
       order_book get_order_book( const string& base, const string& quote, unsigned limit = 50 )const;
 
+      /**
+       * @brief Returns vector of 24 hour volume markets sorted by reverse base_volume
+       * @param limit Max number of results
+       * @return Desc Sorted volume vector
+       */
+      vector<market_volume> get_top_markets(uint limit)const;
+
       /**
        * @brief Returns recent trades for the market assetA:assetB, ordered by time, most recent first. The range is [stop, start)
        * Note: Currently, timezone offsets are not supported. The time must be UTC.
@@ -715,6 +722,7 @@ FC_API(graphene::app::database_api,
    (unsubscribe_from_market)
    (get_ticker)
    (get_24_volume)
+   (get_top_markets)
    (get_trade_history)
    (get_trade_history_by_sequence)
 

libraries/plugins/market_history/include/graphene/market_history/market_history_plugin.hpp

@@ -194,10 +194,12 @@ typedef multi_index_container<
 > order_history_multi_index_type;
 
 struct by_market;
+struct by_volume;
 typedef multi_index_container<
    market_ticker_object,
    indexed_by<
       ordered_unique< tag<by_id>, member< object, object_id_type, &object::id > >,
+      ordered_non_unique< tag<by_volume>, member< market_ticker_object, fc::uint128, &market_ticker_object::base_volume > >,
       ordered_unique<
          tag<by_market>,
          composite_key<