Collateral asset fee accumulator for BSIPs 74 and 87

libraries/chain/asset_evaluator.cpp

@@ -55,7 +55,16 @@ namespace detail {
                    "Taker fee percent should not be defined before HARDFORK_BSIP_81_TIME");
       }
    }
-}
+
+   void check_asset_claim_fees_hardfork_87_74_collatfee(const fc::time_point_sec& block_time, const asset_claim_fees_operation& op)
+   {
+      // HF_REMOVABLE: Following hardfork check should be removable after hardfork date passes:
+      FC_ASSERT( !op.extensions.value.claim_from_asset_id.valid() ||
+                 block_time >= HARDFORK_CORE_BSIP_87_74_COLLATFEE_TIME,
+                 "Collateral-denominated fees are not yet active and therefore cannot be claimed." );
+   }
+
+} // graphene::chain::detail
 
 void_result asset_create_evaluator::do_evaluate( const asset_create_operation& op )
 { try {
@@ -455,6 +464,9 @@ void_result asset_update_bitasset_evaluator::do_evaluate(const asset_update_bita
       FC_ASSERT( asset_obj.dynamic_asset_data_id(d).current_supply == 0,
                  "Cannot update a bitasset if there is already a current supply." );
 
+      FC_ASSERT( asset_obj.dynamic_asset_data_id(d).accumulated_collateral_fees == 0,
+                 "Must claim collateral-denominated fees before changing backing asset." );
+
       const asset_object& new_backing_asset = op.new_options.short_backing_asset(d); // check if the asset exists
 
       if( after_hf_core_922_931 )
@@ -920,25 +932,58 @@ void_result asset_publish_feeds_evaluator::do_apply(const asset_publish_feed_ope
 } FC_CAPTURE_AND_RETHROW((o)) }
 
 
-
+/***
+ * @brief evaluator for asset_claim_fees operation
+ *
+ * Checks that we are able to claim fees denominated in asset Y (the amount_to_claim asset),
+ * from some container asset X which is presumed to have accumulated the fees we wish to claim.
+ * The container asset is either explicitly named in the extensions, or else assumed as the same
+ * asset as the amount_to_claim asset. Evaluation fails if either (a) operation issuer is not
+ * the same as the container_asset issuer, or (b) container_asset has no fee bucket for
+ * amount_to_claim asset, or (c) accumulated fees are insufficient to cover amount claimed.
+ */
 void_result asset_claim_fees_evaluator::do_evaluate( const asset_claim_fees_operation& o )
 { try {
-   FC_ASSERT( o.amount_to_claim.asset_id(db()).issuer == o.issuer, "Asset fees may only be claimed by the issuer" );
+   const database& d = db();
+
+   detail::check_asset_claim_fees_hardfork_87_74_collatfee(d.head_block_time(), o); // HF_REMOVABLE
+
+   container_asset = o.extensions.value.claim_from_asset_id.valid() ?
+      &(*o.extensions.value.claim_from_asset_id)(d) : &o.amount_to_claim.asset_id(d);
+
+   FC_ASSERT( container_asset->issuer == o.issuer, "Asset fees may only be claimed by the issuer" );
+   FC_ASSERT( container_asset->can_accumulate_fee(d,o.amount_to_claim),
+              "Asset ${a} (${id}) is not backed by asset (${fid}) and does not hold it as fees.",
+              ("a",container_asset->symbol)("id",container_asset->id)("fid",o.amount_to_claim.asset_id) );
+
+   container_ddo = &container_asset->dynamic_asset_data_id(d);
+
+   FC_ASSERT( o.amount_to_claim.amount <= ((container_asset->get_id() == o.amount_to_claim.asset_id) ?
+                                           container_ddo->accumulated_fees :
+                                           container_ddo->accumulated_collateral_fees),
+              "Attempt to claim more fees than have accumulated within asset ${a} (${id})",
+              ("a",container_asset->symbol)("id",container_asset->id)("ddo",*container_ddo) );
+
    return void_result();
 } FC_CAPTURE_AND_RETHROW( (o) ) }
 
 
+/***
+ * @brief apply asset_claim_fees operation
+ */
 void_result asset_claim_fees_evaluator::do_apply( const asset_claim_fees_operation& o )
 { try {
    database& d = db();
 
-   const asset_object& a = o.amount_to_claim.asset_id(d);
-   const asset_dynamic_data_object& addo = a.dynamic_asset_data_id(d);
-   FC_ASSERT( o.amount_to_claim.amount <= addo.accumulated_fees, "Attempt to claim more fees than have accumulated", ("addo",addo) );
-
-   d.modify( addo, [&]( asset_dynamic_data_object& _addo  ) {
-     _addo.accumulated_fees -= o.amount_to_claim.amount;
-   });
+   if ( container_asset->get_id() == o.amount_to_claim.asset_id ) {
+      d.modify( *container_ddo, [&o]( asset_dynamic_data_object& _addo  ) {
+         _addo.accumulated_fees -= o.amount_to_claim.amount;
+      });
+   } else {
+      d.modify( *container_ddo, [&o]( asset_dynamic_data_object& _addo  ) {
+         _addo.accumulated_collateral_fees -= o.amount_to_claim.amount;
+      });
+   }
 
    d.adjust_balance( o.issuer, o.amount_to_claim );
 

libraries/chain/asset_object.cpp

@@ -178,7 +178,7 @@ string asset_object::amount_to_string(share_type amount) const
 }
 
 FC_REFLECT_DERIVED_NO_TYPENAME( graphene::chain::asset_dynamic_data_object, (graphene::db::object),
-                    (current_supply)(confidential_supply)(accumulated_fees)(fee_pool) )
+                    (current_supply)(confidential_supply)(accumulated_fees)(accumulated_collateral_fees)(fee_pool) )
 
 FC_REFLECT_DERIVED_NO_TYPENAME( graphene::chain::asset_bitasset_data_object, (graphene::db::object),
                     (asset_id)

libraries/chain/hardfork.d/CORE_BSIP_87_74_COLLATFEE.hf

@@ -0,0 +1,7 @@
+// This hardfork enables the extension to asset_claim_fees_operation to claim collateral-denominated fees.
+// These fees are collected by BSIPs 87 and 74.  This should be set to match the earlier of either
+// HARDFORK_CORE_BSIP87_TIME or HARDFORK_CORE_BSIP74_TIME.
+// This hardfork check should be removable after the hardfork date passes.
+#ifndef HARDFORK_CORE_BSIP_87_74_COLLATFEE_TIME
+#define HARDFORK_CORE_BSIP_87_74_COLLATFEE_TIME (fc::time_point_sec( 1679955066 ) ) // Temporary date until actual hardfork date is set
+#endif

libraries/chain/include/graphene/chain/asset_evaluator.hpp

@@ -166,6 +166,9 @@ namespace graphene { namespace chain {
 
          void_result do_evaluate( const asset_claim_fees_operation& o );
          void_result do_apply( const asset_claim_fees_operation& o );
+
+         const asset_object* container_asset = nullptr;
+         const asset_dynamic_data_object* container_ddo = nullptr;
    };
 
    class asset_claim_pool_evaluator : public evaluator<asset_claim_pool_evaluator>

libraries/chain/include/graphene/chain/asset_object.hpp

@@ -65,6 +65,7 @@ namespace graphene { namespace chain {
          share_type current_supply;
          share_type confidential_supply; ///< total asset held in confidential balances
          share_type accumulated_fees; ///< fees accumulate to be paid out over time
+         share_type accumulated_collateral_fees; ///< accumulated collateral-denominated fees (for bitassets)
          share_type fee_pool;         ///< in core asset
    };
 
@@ -164,6 +165,46 @@ namespace graphene { namespace chain {
          template<class DB>
          share_type reserved( const DB& db )const
          { return options.max_supply - dynamic_data(db).current_supply; }
+
+         /// @return true if asset can accumulate fees in the given denomination
+         template<class DB>
+         bool can_accumulate_fee(const DB& db, const asset& fee) const {
+            return (( fee.asset_id == get_id() ) ||
+                    ( is_market_issued() && fee.asset_id == bitasset_data(db).options.short_backing_asset ));
+         }
+
+         /***
+          * @brief receive a fee asset to accrue in dynamic_data object
+          *
+          * Asset owners define various fees (market fees, force-settle fees, etc.) to be
+          * collected for the asset owners. These fees are typically denominated in the asset
+          * itself, but for bitassets some of the fees are denominated in the collateral
+          * asset. This will place the fee in the right container.
+          */
+         template<class DB>
+         void accumulate_fee(DB& db, const asset& fee) const
+         {
+            if (fee.amount == 0) return;
+            FC_ASSERT( fee.amount >= 0, "Fee amount must be non-negative." );
+            const auto& dyn_data = dynamic_asset_data_id(db);
+            if (fee.asset_id == get_id()) { // fee same as asset
+               db.modify( dyn_data, [&fee]( asset_dynamic_data_object& obj ){
+                  obj.accumulated_fees += fee.amount;
+               });
+            } else { // fee different asset; perhaps collateral-denominated fee
+               FC_ASSERT( is_market_issued(),
+                          "Asset ${a} (${id}) cannot accept fee of asset (${fid}).",
+                          ("a",this->symbol)("id",this->id)("fid",fee.asset_id) );
+               const auto & bad = bitasset_data(db);
+               FC_ASSERT( fee.asset_id == bad.options.short_backing_asset,
+                          "Asset ${a} (${id}) cannot accept fee of asset (${fid}).",
+                          ("a",this->symbol)("id",this->id)("fid",fee.asset_id) );
+               db.modify( dyn_data, [&fee]( asset_dynamic_data_object& obj ){
+                  obj.accumulated_collateral_fees += fee.amount;
+               });
+            }
+         }
+
    };
 
    /**

libraries/chain/proposal_evaluator.cpp

@@ -31,6 +31,7 @@ namespace graphene { namespace chain {
 namespace detail {
    void check_asset_options_hf_1774(const fc::time_point_sec& block_time, const asset_options& options);   
    void check_asset_options_hf_bsip81(const fc::time_point_sec& block_time, const asset_options& options);
+   void check_asset_claim_fees_hardfork_87_74_collatfee(const fc::time_point_sec& block_time, const asset_claim_fees_operation& op);
 }
 
 struct proposal_operation_hardfork_visitor
@@ -61,6 +62,10 @@ struct proposal_operation_hardfork_visitor
       detail::check_asset_options_hf_bsip81(block_time, v.new_options);
    }
 
+   void operator()(const graphene::chain::asset_claim_fees_operation &v) const {
+      detail::check_asset_claim_fees_hardfork_87_74_collatfee(block_time, v); // HF_REMOVABLE
+   }
+
    void operator()(const graphene::chain::committee_member_update_global_parameters_operation &op) const {
       if (block_time < HARDFORK_CORE_1468_TIME) {
          FC_ASSERT(!op.new_parameters.extensions.value.updatable_htlc_options.valid(), "Unable to set HTLC options before hardfork 1468");

libraries/protocol/asset_ops.cpp

@@ -251,6 +251,8 @@ void asset_options::validate()const
 void asset_claim_fees_operation::validate()const {
    FC_ASSERT( fee.amount >= 0 );
    FC_ASSERT( amount_to_claim.amount > 0 );
+   if( extensions.value.claim_from_asset_id.valid() )
+     FC_ASSERT( *extensions.value.claim_from_asset_id != amount_to_claim.asset_id );
 }
 
 void asset_claim_pool_operation::validate()const {
@@ -271,6 +273,7 @@ GRAPHENE_IMPLEMENT_EXTERNAL_SERIALIZATION( graphene::protocol::asset_settle_oper
 GRAPHENE_IMPLEMENT_EXTERNAL_SERIALIZATION( graphene::protocol::asset_fund_fee_pool_operation::fee_parameters_type )
 GRAPHENE_IMPLEMENT_EXTERNAL_SERIALIZATION( graphene::protocol::asset_claim_pool_operation::fee_parameters_type )
 GRAPHENE_IMPLEMENT_EXTERNAL_SERIALIZATION( graphene::protocol::asset_claim_fees_operation::fee_parameters_type )
+GRAPHENE_IMPLEMENT_EXTERNAL_SERIALIZATION( graphene::protocol::asset_claim_fees_operation::additional_options_type )
 GRAPHENE_IMPLEMENT_EXTERNAL_SERIALIZATION( graphene::protocol::asset_update_operation::fee_parameters_type )
 GRAPHENE_IMPLEMENT_EXTERNAL_SERIALIZATION( graphene::protocol::asset_update_issuer_operation::fee_parameters_type )
 GRAPHENE_IMPLEMENT_EXTERNAL_SERIALIZATION( graphene::protocol::asset_update_bitasset_operation::fee_parameters_type )

libraries/protocol/include/graphene/protocol/asset_ops.hpp

@@ -446,10 +446,21 @@ namespace graphene { namespace protocol {
          uint64_t fee = 20 * GRAPHENE_BLOCKCHAIN_PRECISION;
       };
 
+      struct additional_options_type
+      {
+         /// Which asset to claim fees from. This is needed, e.g., to claim collateral-
+         /// denominated fees from a collateral-backed smart asset. If unset, assumed to be same
+         /// asset as amount_to_claim is denominated in, such as would be the case when claiming
+         /// market fees. If set, validation requires it to be a different asset_id than
+         /// amount_to_claim (else there would exist two ways to form the same request).
+         fc::optional<asset_id_type> claim_from_asset_id;
+      };
+
       asset           fee;
-      account_id_type issuer;
-      asset           amount_to_claim; /// amount_to_claim.asset_id->issuer must == issuer
-      extensions_type extensions;
+      account_id_type issuer; ///< must match issuer of asset from which we claim fees
+      asset           amount_to_claim;
+
+      extension<additional_options_type> extensions;
 
       account_id_type fee_payer()const { return issuer; }
       void            validate()const;
@@ -521,6 +532,8 @@ namespace graphene { namespace protocol {
 
 FC_REFLECT( graphene::protocol::asset_claim_fees_operation, (fee)(issuer)(amount_to_claim)(extensions) )
 FC_REFLECT( graphene::protocol::asset_claim_fees_operation::fee_parameters_type, (fee) )
+FC_REFLECT( graphene::protocol::asset_claim_fees_operation::additional_options_type, (claim_from_asset_id) )
+
 FC_REFLECT( graphene::protocol::asset_claim_pool_operation, (fee)(issuer)(asset_id)(amount_to_claim)(extensions) )
 FC_REFLECT( graphene::protocol::asset_claim_pool_operation::fee_parameters_type, (fee) )
 
@@ -619,6 +632,7 @@ GRAPHENE_DECLARE_EXTERNAL_SERIALIZATION( graphene::protocol::asset_settle_operat
 GRAPHENE_DECLARE_EXTERNAL_SERIALIZATION( graphene::protocol::asset_fund_fee_pool_operation::fee_parameters_type )
 GRAPHENE_DECLARE_EXTERNAL_SERIALIZATION( graphene::protocol::asset_claim_pool_operation::fee_parameters_type )
 GRAPHENE_DECLARE_EXTERNAL_SERIALIZATION( graphene::protocol::asset_claim_fees_operation::fee_parameters_type )
+GRAPHENE_DECLARE_EXTERNAL_SERIALIZATION( graphene::protocol::asset_claim_fees_operation::additional_options_type )
 GRAPHENE_DECLARE_EXTERNAL_SERIALIZATION( graphene::protocol::asset_update_operation::fee_parameters_type )
 GRAPHENE_DECLARE_EXTERNAL_SERIALIZATION( graphene::protocol::asset_update_issuer_operation::fee_parameters_type )
 GRAPHENE_DECLARE_EXTERNAL_SERIALIZATION( graphene::protocol::asset_update_bitasset_operation::fee_parameters_type )

tests/common/database_fixture.cpp

@@ -529,6 +529,7 @@ void database_fixture::verify_asset_supplies( const database& db )
       {
          const auto& bad = asset_obj.bitasset_data(db);
          total_balances[bad.options.short_backing_asset] += bad.settlement_fund;
+         total_balances[bad.options.short_backing_asset] += dasset_obj.accumulated_collateral_fees;
       }
       total_balances[asset_obj.id] += dasset_obj.confidential_supply.value;
    }