Add db API to find liquidity pools by one asset

libraries/app/database_api.cpp

@@ -84,6 +84,16 @@ database_api_impl::database_api_impl( graphene::chain::database& db, const appli
    {
       amount_in_collateral_index = nullptr;
    }
+
+   try
+   {
+      asset_in_liquidity_pools_index = &_db.get_index_type< primary_index< liquidity_pool_index > >()
+            .get_secondary_index<graphene::api_helper_indexes::asset_in_liquidity_pools_index>();
+   }
+   catch( fc::assert_exception& e )
+   {
+      asset_in_liquidity_pools_index = nullptr;
+   }
 }
 
 database_api_impl::~database_api_impl()
@@ -1816,6 +1826,57 @@ vector<extended_liquidity_pool_object> database_api_impl::get_liquidity_pools_by
             with_statistics );
 }
 
+vector<extended_liquidity_pool_object> database_api::get_liquidity_pools_by_one_asset(
+            std::string asset_symbol_or_id,
+            optional<uint32_t> limit,
+            optional<liquidity_pool_id_type> start_id,
+            optional<bool> with_statistics )const
+{
+   return my->get_liquidity_pools_by_one_asset(
+            asset_symbol_or_id,
+            limit,
+            start_id,
+            with_statistics );
+}
+
+vector<extended_liquidity_pool_object> database_api_impl::get_liquidity_pools_by_one_asset(
+            std::string asset_symbol_or_id,
+            optional<uint32_t> olimit,
+            optional<liquidity_pool_id_type> ostart_id,
+            optional<bool> with_statistics )const
+{
+   // api_helper_indexes plugin is required for accessing the secondary index
+   FC_ASSERT( _app_options && _app_options->has_api_helper_indexes_plugin,
+              "api_helper_indexes plugin is not enabled on this server." );
+
+   uint32_t limit = olimit.valid() ? *olimit : 101;
+   const auto configured_limit = _app_options->api_limit_get_liquidity_pools;
+   FC_ASSERT( limit <= configured_limit,
+              "limit can not be greater than ${configured_limit}",
+              ("configured_limit", configured_limit) );
+
+   asset_id_type aid = get_asset_from_string(asset_symbol_or_id)->id;
+
+   FC_ASSERT( asset_in_liquidity_pools_index, "Internal error" );
+   const auto& pools = asset_in_liquidity_pools_index->get_liquidity_pools_by_asset( aid );
+
+   liquidity_pool_id_type start_id = ostart_id.valid() ? *ostart_id : liquidity_pool_id_type();
+
+   auto itr = pools.lower_bound( start_id );
+
+   bool with_stats = ( with_statistics.valid() && *with_statistics );
+
+   vector<extended_liquidity_pool_object> results;
+
+   results.reserve( limit );
+   for ( ; itr != pools.end() && results.size() < limit; ++itr )
+   {
+      results.emplace_back( extend_liquidity_pool( (*itr)(_db), with_stats ) );
+   }
+
+   return results;
+}
+
 vector<extended_liquidity_pool_object> database_api::get_liquidity_pools_by_both_assets(
             std::string asset_symbol_or_id_a,
             std::string asset_symbol_or_id_b,

libraries/app/database_api_impl.hxx

@@ -153,6 +153,11 @@ class database_api_impl : public std::enable_shared_from_this<database_api_impl>
             optional<uint32_t> limit = 101,
             optional<liquidity_pool_id_type> start_id = optional<liquidity_pool_id_type>(),
             optional<bool> with_statistics = false )const;
+      vector<extended_liquidity_pool_object> get_liquidity_pools_by_one_asset(
+            std::string asset_symbol_or_id,
+            optional<uint32_t> limit = 101,
+            optional<liquidity_pool_id_type> start_id = optional<liquidity_pool_id_type>(),
+            optional<bool> with_statistics = false )const;
       vector<extended_liquidity_pool_object> get_liquidity_pools_by_both_assets(
             std::string asset_symbol_or_id_a,
             std::string asset_symbol_or_id_b,
@@ -465,6 +470,7 @@ class database_api_impl : public std::enable_shared_from_this<database_api_impl>
       const application_options* _app_options = nullptr;
 
       const graphene::api_helper_indexes::amount_in_collateral_index* amount_in_collateral_index;
+      const graphene::api_helper_indexes::asset_in_liquidity_pools_index* asset_in_liquidity_pools_index;
 };
 
 } } // graphene::app

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

@@ -691,6 +691,26 @@ class database_api
             optional<liquidity_pool_id_type> start_id = optional<liquidity_pool_id_type>(),
             optional<bool> with_statistics = false )const;
 
+      /**
+       * @brief Get a list of liquidity pools by the symbol or ID of one asset in the pool
+       * @param asset_symbol_or_id symbol name or ID of the asset
+       * @param limit  The limitation of items each query can fetch, not greater than a configured value
+       * @param start_id  Start liquidity pool id, fetch pools whose IDs are greater than or equal to this ID
+       * @param with_statistics Whether to return statistics
+       * @return The liquidity pools
+       *
+       * @note
+       * 1. if @p asset_symbol_or_id cannot be tied to an asset, an error will be returned
+       * 2. @p limit can be omitted or be null, if so the default value 101 will be used
+       * 3. @p start_id can be omitted or be null, if so the api will return the "first page" of pools
+       * 4. can only omit one or more arguments in the end of the list, but not one or more in the middle
+       */
+      vector<extended_liquidity_pool_object> get_liquidity_pools_by_one_asset(
+            std::string asset_symbol_or_id,
+            optional<uint32_t> limit = 101,
+            optional<liquidity_pool_id_type> start_id = optional<liquidity_pool_id_type>(),
+            optional<bool> with_statistics = false )const;
+
       /**
        * @brief Get a list of liquidity pools by the symbols or IDs of the two assets in the pool
        * @param asset_symbol_or_id_a symbol name or ID of one asset
@@ -1179,6 +1199,7 @@ FC_API(graphene::app::database_api,
    (list_liquidity_pools)
    (get_liquidity_pools_by_asset_a)
    (get_liquidity_pools_by_asset_b)
+   (get_liquidity_pools_by_one_asset)
    (get_liquidity_pools_by_both_assets)
    (get_liquidity_pools)
    (get_liquidity_pools_by_share_asset)