peerplays_migrated/libraries/chain/include/graphene/chain/evaluator.hpp
Nathan Hourt 377432453f Lay to rest #16
It's finally done.
2015-06-16 14:42:05 -04:00

216 lines
8.3 KiB
C++

/*
* Copyright (c) 2015, Cryptonomex, Inc.
* All rights reserved.
*
* This source code is provided for evaluation in private test networks only, until September 8, 2015. After this date, this license expires and
* the code may not be used, modified or distributed for any purpose. Redistribution and use in source and binary forms, with or without modification,
* are permitted until September 8, 2015, provided that the following conditions are met:
*
* 1. The code and/or derivative works are used only for private test networks consisting of no more than 10 P2P nodes.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <graphene/chain/operations.hpp>
#include <graphene/chain/authority.hpp>
namespace graphene { namespace chain {
class database;
class generic_evaluator;
class transaction_evaluation_state;
/**
* Observes evaluation events, providing
* pre- and post-evaluation hooks.
*
* Every call to pre_evaluate() is followed by
* a call to either post_evaluate() or evaluation_failed().
*
* A subclass which needs to do a "diff" can gather some
* "before" state into its members in pre_evaluate(),
* then post_evaluate() will have both "before"
* and "after" state, and will be able to do the diff.
*
* evaluation_failed() is a cleanup method which notifies
* the subclass to "throw away" the diff.
*/
class evaluation_observer
{
public:
virtual ~evaluation_observer(){}
virtual void pre_evaluate(
const transaction_evaluation_state& eval_state,
const operation& op,
bool apply,
generic_evaluator* ge ) {}
virtual void post_evaluate(
const transaction_evaluation_state& eval_state,
const operation& op,
bool apply,
generic_evaluator* ge,
const operation_result& result ) {}
virtual void evaluation_failed(
const transaction_evaluation_state& eval_state,
const operation& op,
bool apply,
generic_evaluator* ge,
const operation_result& result ) {}
};
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 );
/** @note derived classes should ASSUME that the default validation that is
* indepenent of chain state should be performed by op.validate() and should
* not perform these extra checks.
*/
virtual operation_result evaluate( const operation& op ) = 0;
virtual operation_result apply( const operation& op ) = 0;
database& db()const;
void check_required_authorities(const operation& op);
protected:
/**
* @brief Fetch objects relevant to fee payer and set pointer members
* @param account_id Account which is paying the fee
* @param fee The fee being paid. May be in assets other than core.
*
* This method verifies that the fee is valid and sets the object pointer members and the fee fields. It should
* be called during do_evaluate.
*/
void prepare_fee(account_id_type account_id, asset fee);
/// Pays the fee and returns the number of CORE asset that were paid.
void pay_fee();
bool verify_authority( const account_object&, authority::classification );
//bool verify_signature( const key_object& );
object_id_type get_relative_id( object_id_type rel_id )const;
void check_relative_ids(const authority& a)const;
authority resolve_relative_ids( const authority& a )const;
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;
vector< evaluation_observer* > eval_observers;
};
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
{
// fc::exception from observers are suppressed.
// fc::exception from evaluation is deferred (re-thrown
// after all observers receive evaluation_failed)
T eval;
optional< fc::exception > evaluation_exception;
size_t observer_count = 0;
operation_result result;
for( const auto& obs : eval_observers )
{
try
{
obs->pre_evaluate( eval_state, op, apply, &eval );
}
catch( const fc::exception& e )
{
elog( "suppressed exception in observer pre method:\n${e}", ( "e", e.to_detail_string() ) );
}
observer_count++;
}
try
{
result = eval.start_evaluate( eval_state, op, apply );
}
catch( const fc::exception& e )
{
evaluation_exception = e;
}
while( observer_count > 0 )
{
--observer_count;
const auto& obs = eval_observers[ observer_count ];
try
{
if( !evaluation_exception.valid() )
obs->post_evaluate( eval_state, op, apply, &eval, result );
else
obs->evaluation_failed( eval_state, op, apply, &eval, result );
}
catch( const fc::exception& e )
{
elog( "suppressed exception in observer post method:\n${e}", ( "e", e.to_detail_string() ) );
}
}
if( evaluation_exception.valid() )
throw *evaluation_exception;
return result;
}
};
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);
FC_ASSERT( core_fee_paid >= op.calculate_fee(db().current_fee_schedule()) );
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>();
pay_fee();
auto result = eval->do_apply( op );
db().adjust_balance(op.fee_payer(), -fee_from_account);
return result;
}
};
} }