evaluator.hpp

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/*
 * Copyright (c) 2015 Cryptonomex, Inc., and contributors.
 *
 * The MIT License
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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#pragma once
#include <graphene/chain/exceptions.hpp>
#include <graphene/chain/transaction_evaluation_state.hpp>
#include <graphene/protocol/operations.hpp>

namespace graphene { namespace chain {

   class database;
   class generic_evaluator;
   class transaction_evaluation_state;
   class account_object;
   class account_statistics_object;
   class asset_object;
   class asset_dynamic_data_object;

   class generic_evaluator
   {
   public:
      virtual ~generic_evaluator(){}

      virtual int get_type()const = 0;
      virtual operation_result start_evaluate(transaction_evaluation_state& eval_state, const operation& op, bool apply);

      virtual operation_result evaluate(const operation& op) = 0;
      virtual operation_result apply(const operation& op) = 0;

      virtual void pay_fee();

      database& db()const;

      //void check_required_authorities(const operation& op);
   protected:
      void prepare_fee(account_id_type account_id, asset fee);

      virtual void convert_fee();

      object_id_type get_relative_id( object_id_type rel_id )const;

      void pay_fba_fee( uint64_t fba_id );

      // the next two functions are helpers that allow template functions declared in this 
      // header to call db() without including database.hpp, which would
      // cause a circular dependency
      share_type calculate_fee_for_operation(const operation& op) const;
      void db_adjust_balance(const account_id_type& fee_payer, asset fee_from_account);

      asset                            fee_from_account;
      share_type                       core_fee_paid;
      const account_object*            fee_paying_account = nullptr;
      const account_statistics_object* fee_paying_account_statistics = nullptr;
      const asset_object*              fee_asset          = nullptr;
      const asset_dynamic_data_object* fee_asset_dyn_data = nullptr;
      transaction_evaluation_state*    trx_state;
   };

   class op_evaluator
   {
   public:
      virtual ~op_evaluator(){}
      virtual operation_result evaluate(transaction_evaluation_state& eval_state, const operation& op, bool apply) = 0;
   };

   template<typename T>
   class op_evaluator_impl : public op_evaluator
   {
   public:
      virtual operation_result evaluate(transaction_evaluation_state& eval_state, const operation& op, bool apply = true) override
      {
         T eval;
         return eval.start_evaluate(eval_state, op, apply);
      }
   };

   template<typename DerivedEvaluator>
   class evaluator : public generic_evaluator
   {
   public:
      virtual int get_type()const override { return operation::tag<typename DerivedEvaluator::operation_type>::value; }

      virtual operation_result evaluate(const operation& o) final override
      {
         auto* eval = static_cast<DerivedEvaluator*>(this);
         const auto& op = o.get<typename DerivedEvaluator::operation_type>();

         prepare_fee(op.fee_payer(), op.fee);
         if( !trx_state->skip_fee_schedule_check )
         {
            share_type required_fee = calculate_fee_for_operation(op);
            GRAPHENE_ASSERT( core_fee_paid >= required_fee,
                       insufficient_fee,
                       "Insufficient Fee Paid",
                       ("core_fee_paid",core_fee_paid)("required", required_fee) );
         }

         return eval->do_evaluate(op);
      }

      virtual operation_result apply(const operation& o) final override
      {
         auto* eval = static_cast<DerivedEvaluator*>(this);
         const auto& op = o.get<typename DerivedEvaluator::operation_type>();

         convert_fee();
         pay_fee();

         auto result = eval->do_apply(op);

         db_adjust_balance(op.fee_payer(), -fee_from_account);

         return result;
      }
   };
} }