peerplays_migrated/libraries/chain/db_update.cpp

/*
 * 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
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <graphene/chain/database.hpp>
#include <graphene/chain/db_with.hpp>

#include <graphene/chain/asset_object.hpp>
#include <graphene/chain/betting_market_object.hpp>
#include <graphene/chain/game_object.hpp>
#include <graphene/chain/global_property_object.hpp>
#include <graphene/chain/hardfork.hpp>
#include <graphene/chain/market_object.hpp>
#include <graphene/chain/offer_object.hpp>
#include <graphene/chain/proposal_object.hpp>
#include <graphene/chain/son_proposal_object.hpp>
#include <graphene/chain/tournament_object.hpp>
#include <graphene/chain/transaction_object.hpp>
#include <graphene/chain/withdraw_permission_object.hpp>
#include <graphene/chain/witness_object.hpp>

#include <graphene/chain/protocol/fee_schedule.hpp>

#include <fc/uint128.hpp>

namespace graphene { namespace chain {

void database::update_global_dynamic_data( const signed_block& b, const uint32_t missed_blocks )
{
   const dynamic_global_property_object& _dgp = get_dynamic_global_properties();

   // dynamic global properties updating
   modify( _dgp, [&b,this,missed_blocks]( dynamic_global_property_object& dgp ){
      secret_hash_type::encoder enc;       
      fc::raw::pack( enc, dgp.random );       
      fc::raw::pack( enc, b.previous_secret );        
      dgp.random = enc.result();

      _random_number_generator = fc::hash_ctr_rng<secret_hash_type, 20>(dgp.random.data());

      const uint32_t block_num = b.block_num();
      if( BOOST_UNLIKELY( block_num == 1 ) )
         dgp.recently_missed_count = 0;
      else if( _checkpoints.size() && _checkpoints.rbegin()->first >= block_num )
         dgp.recently_missed_count = 0;
      else if( missed_blocks )
         dgp.recently_missed_count += GRAPHENE_RECENTLY_MISSED_COUNT_INCREMENT*missed_blocks;
      else if( dgp.recently_missed_count > GRAPHENE_RECENTLY_MISSED_COUNT_INCREMENT )
         dgp.recently_missed_count -= GRAPHENE_RECENTLY_MISSED_COUNT_DECREMENT;
      else if( dgp.recently_missed_count > 0 )
         dgp.recently_missed_count--;

      dgp.head_block_number = block_num;
      dgp.head_block_id = b.id();
      dgp.time = b.timestamp;
      dgp.current_witness = b.witness;
      dgp.recent_slots_filled = (
           (dgp.recent_slots_filled << 1)
           + 1) << missed_blocks;
      dgp.current_aslot += missed_blocks+1;
   });

   if( !(get_node_properties().skip_flags & skip_undo_history_check) )
   {
      GRAPHENE_ASSERT( _dgp.head_block_number - _dgp.last_irreversible_block_num  < GRAPHENE_MAX_UNDO_HISTORY, undo_database_exception,
                 "The database does not have enough undo history to support a blockchain with so many missed blocks. "
                 "Please add a checkpoint if you would like to continue applying blocks beyond this point.",
                 ("last_irreversible_block_num",_dgp.last_irreversible_block_num)("head", _dgp.head_block_number)
                 ("recently_missed",_dgp.recently_missed_count)("max_undo",GRAPHENE_MAX_UNDO_HISTORY) );
   }

   _undo_db.set_max_size( _dgp.head_block_number - _dgp.last_irreversible_block_num + 1 );
   _fork_db.set_max_size( _dgp.head_block_number - _dgp.last_irreversible_block_num + 1 );
}

void database::update_signing_witness(const witness_object& signing_witness, const signed_block& new_block)
{
   const global_property_object& gpo = get_global_properties();
   const dynamic_global_property_object& dpo = get_dynamic_global_properties();
   uint64_t new_block_aslot = dpo.current_aslot + get_slot_at_time( new_block.timestamp );

   share_type witness_pay = std::min( gpo.parameters.witness_pay_per_block, dpo.witness_budget );

   modify( dpo, [&]( dynamic_global_property_object& _dpo )
   {
      _dpo.witness_budget -= witness_pay;
   } );

   deposit_witness_pay( signing_witness, witness_pay );

   modify( signing_witness, [&]( witness_object& _wit )
   {
      _wit.last_aslot = new_block_aslot;
      _wit.last_confirmed_block_num = new_block.block_num();
      _wit.previous_secret = new_block.previous_secret;
      _wit.next_secret_hash = new_block.next_secret_hash;
   } );
}

void database::update_last_irreversible_block()
{
   const global_property_object& gpo = get_global_properties();
   const dynamic_global_property_object& dpo = get_dynamic_global_properties();

   // TODO for better performance, move this to db_maint, because only need to do it once per maintenance interval
   vector< const witness_object* > wit_objs;
   wit_objs.reserve( gpo.active_witnesses.size() );
   for( const witness_id_type& wid : gpo.active_witnesses )
      wit_objs.push_back( &(wid(*this)) );

   static_assert( GRAPHENE_IRREVERSIBLE_THRESHOLD > 0, "irreversible threshold must be nonzero" );

   // 1 1 1 2 2 2 2 2 2 2 -> 2     .7*10 = 7
   // 1 1 1 1 1 1 1 2 2 2 -> 1
   // 3 3 3 3 3 3 3 3 3 3 -> 3

   size_t offset = ((GRAPHENE_100_PERCENT - GRAPHENE_IRREVERSIBLE_THRESHOLD) * wit_objs.size() / GRAPHENE_100_PERCENT);

   std::nth_element( wit_objs.begin(), wit_objs.begin() + offset, wit_objs.end(),
      []( const witness_object* a, const witness_object* b )
      {
         return a->last_confirmed_block_num < b->last_confirmed_block_num;
      } );

   uint32_t new_last_irreversible_block_num = wit_objs[offset]->last_confirmed_block_num;

   if( new_last_irreversible_block_num > dpo.last_irreversible_block_num )
   {
      modify( dpo, [&]( dynamic_global_property_object& _dpo )
      {
         _dpo.last_irreversible_block_num = new_last_irreversible_block_num;
      } );
   }
}
void database::clear_expired_transactions()
{ try {
   //Look for expired transactions in the deduplication list, and remove them.
   //Transactions must have expired by at least two forking windows in order to be removed.
   auto& transaction_idx = static_cast<transaction_index&>(get_mutable_index(implementation_ids, impl_transaction_object_type));
   const auto& dedupe_index = transaction_idx.indices().get<by_expiration>();
   while( (!dedupe_index.empty()) && (head_block_time() > dedupe_index.begin()->trx.expiration) )
      transaction_idx.remove(*dedupe_index.begin());
} FC_CAPTURE_AND_RETHROW() }

void database::place_delayed_bets()
{ try {
   // If any bets have been placed during live betting where bets are delayed for a few seconds, see if there are
   // any bets whose delays have expired.

   // Delayed bets are sorted to the beginning of the order book, so if there are any bets that need placing, 
   // they're right at the front of the book
   const auto& bet_odds_idx = get_index_type<bet_object_index>().indices().get<by_odds>();
   auto iter = bet_odds_idx.begin();

   // we use an awkward looping mechanism here because there's a case where we are processing the
   // last delayed bet before the "real" order book starts and `iter` was pointing at the first 
   // real order.  The place_bet() call can cause the that real order to be deleted, so we need
   // to decide whether this is the last delayed bet before `place_bet` is called.
   bool last = iter == bet_odds_idx.end() || 
               !iter->end_of_delay ||
               *iter->end_of_delay > head_block_time();
   while (!last)
   {
      const bet_object& bet_to_place = *iter;
      ++iter;

      last = iter == bet_odds_idx.end() || 
             !iter->end_of_delay ||
             *iter->end_of_delay > head_block_time();

      // it's possible that the betting market was active when the bet was placed,
      // but has been frozen before the delay expired.  If that's the case here,
      // don't try to match the bet.
      // Since this check happens every block, this could impact performance if a
      // market with many delayed bets is frozen for a long time.
      // Our current understanding is that the witnesses will typically cancel all unmatched
      // bets on frozen markets to avoid this.
      const betting_market_object& betting_market = bet_to_place.betting_market_id(*this);
      if (betting_market.get_status() == betting_market_status::unresolved)
      {
         modify(bet_to_place, [](bet_object& bet_obj) {
            // clear the end_of_delay,  which will re-sort the bet into its place in the book
            bet_obj.end_of_delay.reset();
         });

         place_bet(bet_to_place);
      }
   }
} FC_CAPTURE_AND_RETHROW() }

void database::clear_expired_proposals()
{
   const auto& proposal_expiration_index = get_index_type<proposal_index>().indices().get<by_expiration>();
   while( !proposal_expiration_index.empty() && proposal_expiration_index.begin()->expiration_time <= head_block_time() )
   {
      const proposal_object& proposal = *proposal_expiration_index.begin();
      processed_transaction result;
      try {
         if( proposal.is_authorized_to_execute(*this) )
         {
            result = push_proposal(proposal);
            //TODO: Do something with result so plugins can process it.
            continue;
         }
      } catch( const fc::exception& e ) {
         elog("Failed to apply proposed transaction on its expiration. Deleting it.\n${proposal}\n${error}",
              ("proposal", proposal)("error", e.to_detail_string()));
      }
      remove_son_proposal(proposal);
      remove(proposal);
   }
}

/**
 *  let HB = the highest bid for the collateral  (aka who will pay the most DEBT for the least collateral)
 *  let SP = current median feed's Settlement Price 
 *  let LC = the least collateralized call order's swan price (debt/collateral)
 *
 *  If there is no valid price feed or no bids then there is no black swan.
 *
 *  A black swan occurs if MAX(HB,SP) <= LC
 */
bool database::check_for_blackswan( const asset_object& mia, bool enable_black_swan,
                                    const asset_bitasset_data_object* bitasset_ptr )
{
    if( !mia.is_market_issued() ) return false;

    const asset_bitasset_data_object& bitasset = ( bitasset_ptr ? *bitasset_ptr : mia.bitasset_data(*this) );
    if( bitasset.has_settlement() ) return true; // already force settled
    auto settle_price = bitasset.current_feed.settlement_price;
    if( settle_price.is_null() ) return false; // no feed

    const call_order_object* call_ptr = nullptr; // place holder for the call order with least collateral ratio

    asset_id_type debt_asset_id = mia.id;
    auto call_min = price::min( bitasset.options.short_backing_asset, debt_asset_id );

    auto maint_time = get_dynamic_global_properties().next_maintenance_time;
    bool before_core_hardfork_1270 = ( maint_time <= HARDFORK_CORE_1270_TIME ); // call price caching issue

    if( before_core_hardfork_1270 ) // before core-1270 hard fork, check with call_price
    {
       const auto& call_price_index = get_index_type<call_order_index>().indices().get<by_price>();
       auto call_itr = call_price_index.lower_bound( call_min );
       if( call_itr == call_price_index.end() ) // no call order
          return false;
       call_ptr = &(*call_itr);
    }
    else // after core-1270 hard fork, check with collateralization
    {
       const auto& call_collateral_index = get_index_type<call_order_index>().indices().get<by_collateral>();
       auto call_itr = call_collateral_index.lower_bound( call_min );
       if( call_itr == call_collateral_index.end() ) // no call order
          return false;
       call_ptr = &(*call_itr);
    }
    if( call_ptr->debt_type() != debt_asset_id ) // no call order
       return false;

    price highest = settle_price;
    if( maint_time > HARDFORK_CORE_1270_TIME )
       // due to #338, we won't check for black swan on incoming limit order, so need to check with MSSP here
       highest = bitasset.current_feed.max_short_squeeze_price();
    else if( maint_time > HARDFORK_CORE_338_TIME )
       // due to #338, we won't check for black swan on incoming limit order, so need to check with MSSP here
       highest = bitasset.current_feed.max_short_squeeze_price_before_hf_1270();

    const limit_order_index& limit_index = get_index_type<limit_order_index>();
    const auto& limit_price_index = limit_index.indices().get<by_price>();

    // looking for limit orders selling the most USD for the least CORE
    auto highest_possible_bid = price::max( mia.id, bitasset.options.short_backing_asset );
    // stop when limit orders are selling too little USD for too much CORE
    auto lowest_possible_bid  = price::min( mia.id, bitasset.options.short_backing_asset );

    FC_ASSERT( highest_possible_bid.base.asset_id == lowest_possible_bid.base.asset_id );
    // NOTE limit_price_index is sorted from greatest to least
    auto limit_itr = limit_price_index.lower_bound( highest_possible_bid );
    auto limit_end = limit_price_index.upper_bound( lowest_possible_bid );

    if( limit_itr != limit_end ) {
       FC_ASSERT( highest.base.asset_id == limit_itr->sell_price.base.asset_id );
       highest = std::max( limit_itr->sell_price, highest );
    }

    auto least_collateral = call_ptr->collateralization();
    if( ~least_collateral >= highest  ) 
    {
       wdump( (*call_ptr) );
       elog( "Black Swan detected on asset ${symbol} (${id}) at block ${b}: \n"
             "   Least collateralized call: ${lc}  ${~lc}\n"
           //  "   Highest Bid:               ${hb}  ${~hb}\n"
             "   Settle Price:              ${~sp}  ${sp}\n"
             "   Max:                       ${~h}   ${h}\n",
            ("id",mia.id)("symbol",mia.symbol)("b",head_block_num())
            ("lc",least_collateral.to_real())("~lc",(~least_collateral).to_real())
          //  ("hb",limit_itr->sell_price.to_real())("~hb",(~limit_itr->sell_price).to_real())
            ("sp",settle_price.to_real())("~sp",(~settle_price).to_real())
            ("h",highest.to_real())("~h",(~highest).to_real()) );
       edump((enable_black_swan));
       FC_ASSERT( enable_black_swan, "Black swan was detected during a margin update which is not allowed to trigger a blackswan" );
       if( maint_time > HARDFORK_CORE_338_TIME && ~least_collateral <= settle_price )
          // globol settle at feed price if possible
          globally_settle_asset(mia, settle_price );
       else
          globally_settle_asset(mia, ~least_collateral );
       return true;
    } 
    return false;
}

void database::clear_expired_orders()
{ try {
   //Cancel expired limit orders
   auto head_time = head_block_time();
   auto maint_time = get_dynamic_global_properties().next_maintenance_time;
   bool before_core_hardfork_184 = ( maint_time <= HARDFORK_CORE_184_TIME ); // something-for-nothing
   bool before_core_hardfork_342 = ( maint_time <= HARDFORK_CORE_342_TIME ); // better rounding
   bool before_core_hardfork_606 = ( maint_time <= HARDFORK_CORE_606_TIME ); // feed always trigger call
   auto& limit_index = get_index_type<limit_order_index>().indices().get<by_expiration>();
   while( !limit_index.empty() && limit_index.begin()->expiration <= head_time )
   {
      const limit_order_object& order = *limit_index.begin();
      auto base_asset = order.sell_price.base.asset_id;
      auto quote_asset = order.sell_price.quote.asset_id;
      cancel_limit_order( order );
      if( before_core_hardfork_606 )
      {
         // check call orders
         // Comments below are copied from limit_order_cancel_evaluator::do_apply(...)
         // Possible optimization: order can be called by cancelling a limit order
         //   if the canceled order was at the top of the book.
         // Do I need to check calls in both assets?
         check_call_orders( base_asset( *this ) );
         check_call_orders( quote_asset( *this ) );
      }
   }

   //Process expired force settlement orders
   auto& settlement_index = get_index_type<force_settlement_index>().indices().get<by_expiration>();
   if( !settlement_index.empty() )
   {
      asset_id_type current_asset = settlement_index.begin()->settlement_asset_id();
      asset max_settlement_volume;
      price settlement_fill_price;
      price settlement_price;
      bool current_asset_finished = false;
      bool extra_dump = false;

      auto next_asset = [&current_asset, &current_asset_finished, &settlement_index, &extra_dump] {
         auto bound = settlement_index.upper_bound(current_asset);
         if( bound == settlement_index.end() )
         {
            if( extra_dump )
            {
               ilog( "next_asset() returning false" );
            }
            return false;
         }
         if( extra_dump )
         {
            ilog( "next_asset returning true, bound is ${b}", ("b", *bound) );
         }
         current_asset = bound->settlement_asset_id();
         current_asset_finished = false;
         return true;
      };

      uint32_t count = 0;

      // At each iteration, we either consume the current order and remove it, or we move to the next asset
      for( auto itr = settlement_index.lower_bound(current_asset);
           itr != settlement_index.end();
           itr = settlement_index.lower_bound(current_asset) )
      {
         ++count;
         const force_settlement_object& order = *itr;
         auto order_id = order.id;
         current_asset = order.settlement_asset_id();
         const asset_object& mia_object = get(current_asset);
         const asset_bitasset_data_object& mia = mia_object.bitasset_data(*this);

         extra_dump = ((count >= 1000) && (count <= 1020));

         if( extra_dump )
         {
            wlog( "clear_expired_orders() dumping extra data for iteration ${c}", ("c", count) );
            ilog( "head_block_num is ${hb} current_asset is ${a}", ("hb", head_block_num())("a", current_asset) );
         }

         if( mia.has_settlement() )
         {
            ilog( "Canceling a force settlement because of black swan" );
            cancel_settle_order( order );
            continue;
         }

         // Has this order not reached its settlement date?
         if( order.settlement_date > head_time )
         {
            if( next_asset() )
            {
               if( extra_dump )
               {
                  ilog( "next_asset() returned true when order.settlement_date > head_block_time()" );
               }
               continue;
            }
            break;
         }
         // Can we still settle in this asset?
         if( mia.current_feed.settlement_price.is_null() )
         {
            ilog("Canceling a force settlement in ${asset} because settlement price is null",
                 ("asset", mia_object.symbol));
            cancel_settle_order(order);
            continue;
         }
         if( max_settlement_volume.asset_id != current_asset )
            max_settlement_volume = mia_object.amount(mia.max_force_settlement_volume(mia_object.dynamic_data(*this).current_supply));
         // When current_asset_finished is true, this would be the 2nd time processing the same order.
         // In this case, we move to the next asset.
         if( mia.force_settled_volume >= max_settlement_volume.amount || current_asset_finished )
         {
            /*
            ilog("Skipping force settlement in ${asset}; settled ${settled_volume} / ${max_volume}",
                 ("asset", mia_object.symbol)("settlement_price_null",mia.current_feed.settlement_price.is_null())
                 ("settled_volume", mia.force_settled_volume)("max_volume", max_settlement_volume));
                 */
            if( next_asset() )
            {
               if( extra_dump )
               {
                  ilog( "next_asset() returned true when mia.force_settled_volume >= max_settlement_volume.amount" );
               }
               continue;
            }
            break;
         }

         if( settlement_fill_price.base.asset_id != current_asset )
            settlement_fill_price = mia.current_feed.settlement_price
                                    / ratio_type( GRAPHENE_100_PERCENT - mia.options.force_settlement_offset_percent,
                                                  GRAPHENE_100_PERCENT );

         if( before_core_hardfork_342 )
         {
            auto& pays = order.balance;
            auto receives = (order.balance * mia.current_feed.settlement_price);
            receives.amount = ( fc::uint128_t(receives.amount.value) *
                                (GRAPHENE_100_PERCENT - mia.options.force_settlement_offset_percent) /
                                GRAPHENE_100_PERCENT ).to_uint64();
            assert(receives <= order.balance * mia.current_feed.settlement_price);
            settlement_price = pays / receives;
         }
         else if( settlement_price.base.asset_id != current_asset ) // only calculate once per asset
            settlement_price = settlement_fill_price;

         auto& call_index = get_index_type<call_order_index>().indices().get<by_collateral>();
         asset settled = mia_object.amount(mia.force_settled_volume);
         // Match against the least collateralized short until the settlement is finished or we reach max settlements
         while( settled < max_settlement_volume && find_object(order_id) )
         {
            auto itr = call_index.lower_bound(boost::make_tuple(price::min(mia_object.bitasset_data(*this).options.short_backing_asset,
                                                                           mia_object.get_id())));
            // There should always be a call order, since asset exists!
            assert(itr != call_index.end() && itr->debt_type() == mia_object.get_id());
            asset max_settlement = max_settlement_volume - settled;

            if( order.balance.amount == 0 )
            {
               wlog( "0 settlement detected" );
               cancel_settle_order( order );
               break;
            }
            try {
               asset new_settled = match(*itr, order, settlement_price, max_settlement, settlement_fill_price);
               if( !before_core_hardfork_184 && new_settled.amount == 0 ) // unable to fill this settle order
               {
                  if( find_object( order_id ) ) // the settle order hasn't been cancelled
                     current_asset_finished = true;
                  break;
               }
               settled += new_settled;
               // before hard fork core-342, if new_settled > 0, we'll have:
               // * call order is completely filled (thus itr will change in next loop), or
               // * settle order is completely filled (thus find_object(order_id) will be false so will break out), or
               // * reached max_settlement_volume limit (thus new_settled == max_settlement so will break out).
               //
               // after hard fork core-342, if new_settled > 0, we'll have:
               // * call order is completely filled (thus itr will change in next loop), or
               // * settle order is completely filled (thus find_object(order_id) will be false so will break out), or
               // * reached max_settlement_volume limit, but it's possible that new_settled < max_settlement,
               //   in this case, new_settled will be zero in next iteration of the loop, so no need to check here.
            } 
            catch ( const black_swan_exception& e ) { 
               wlog( "Cancelling a settle_order since it may trigger a black swan: ${o}, ${e}",
                     ("o", order)("e", e.to_detail_string()) );
               cancel_settle_order( order );
               break;
            }
         }
         if( mia.force_settled_volume != settled.amount )
         {
            modify(mia, [settled](asset_bitasset_data_object& b) {
               b.force_settled_volume = settled.amount;
            });
         }
      }
   }
} FC_CAPTURE_AND_RETHROW() }

void database::update_expired_feeds()
{
   const auto head_time = head_block_time();
   const auto next_maint_time = get_dynamic_global_properties().next_maintenance_time;
   bool after_hardfork_615 = ( head_time >= HARDFORK_615_TIME );

   const auto& idx = get_index_type<asset_bitasset_data_index>().indices().get<by_feed_expiration>();
   auto itr = idx.begin();
   while( itr != idx.end() && itr->feed_is_expired( head_time ) )
   {
      const asset_bitasset_data_object& b = *itr;
      ++itr; // not always process begin() because old code skipped updating some assets before hf 615
      bool update_cer = false; // for better performance, to only update bitasset once, also check CER in this function
      const asset_object* asset_ptr = nullptr;
      // update feeds, check margin calls
      if( after_hardfork_615 || b.feed_is_expired_before_hardfork_615( head_time ) )
      {
         auto old_median_feed = b.current_feed;
         modify( b, [head_time,next_maint_time,&update_cer]( asset_bitasset_data_object& abdo )
         {
            abdo.update_median_feeds( head_time, next_maint_time );
            if( abdo.need_to_update_cer() )
            {
               update_cer = true;
               abdo.asset_cer_updated = false;
               abdo.feed_cer_updated = false;
            }
         });
         if( !b.current_feed.settlement_price.is_null() && !( b.current_feed == old_median_feed ) ) // `==` check is safe here
         {
            asset_ptr = &b.asset_id( *this );
            check_call_orders( *asset_ptr, true, false, &b );
         }
      }
      // update CER
      if( update_cer )
      {
         if( !asset_ptr )
            asset_ptr = &b.asset_id( *this );
         if( asset_ptr->options.core_exchange_rate != b.current_feed.core_exchange_rate )
         {
            modify( *asset_ptr, [&b]( asset_object& ao )
            {
               ao.options.core_exchange_rate = b.current_feed.core_exchange_rate;
            });
         }
      }
   } // for each asset whose feed is expired

   // process assets affected by bitshares-core issue 453 before hard fork 615
   if( !after_hardfork_615 )
   {
      for( asset_id_type a : _issue_453_affected_assets )
      {
         check_call_orders( a(*this) );
      }
   }
}

void database::update_core_exchange_rates()
{
   const auto& idx = get_index_type<asset_bitasset_data_index>().indices().get<by_cer_update>();
   if( idx.begin() != idx.end() )
   {
      for( auto itr = idx.rbegin(); itr->need_to_update_cer(); itr = idx.rbegin() )
      {
         const asset_bitasset_data_object& b = *itr;
         const asset_object& a = b.asset_id( *this );
         if( a.options.core_exchange_rate != b.current_feed.core_exchange_rate )
         {
            modify( a, [&b]( asset_object& ao )
            {
               ao.options.core_exchange_rate = b.current_feed.core_exchange_rate;
            });
         }
         modify( b, []( asset_bitasset_data_object& abdo )
         {
            abdo.asset_cer_updated = false;
            abdo.feed_cer_updated = false;
         });
      }
   }
}

void database::update_maintenance_flag( bool new_maintenance_flag )
{
   modify( get_dynamic_global_properties(), [&]( dynamic_global_property_object& dpo )
   {
      auto maintenance_flag = dynamic_global_property_object::maintenance_flag;
      dpo.dynamic_flags =
           (dpo.dynamic_flags & ~maintenance_flag)
         | (new_maintenance_flag ? maintenance_flag : 0);
   } );
   return;
}

void database::update_withdraw_permissions()
{
   auto& permit_index = get_index_type<withdraw_permission_index>().indices().get<by_expiration>();
   while( !permit_index.empty() && permit_index.begin()->expiration <= head_block_time() )
      remove(*permit_index.begin());
}

uint64_t database::get_random_bits( uint64_t bound )
{
   return _random_number_generator(bound);
}

void process_finished_games(database& db)
{
   //auto& games_index = db.get_index_type<game_index>().indices().get<by_id>();
}

void process_finished_matches(database& db)
{
}

void process_in_progress_tournaments(database& db)
{
   auto& start_time_index = db.get_index_type<tournament_index>().indices().get<by_start_time>();
   auto start_iter = start_time_index.lower_bound(boost::make_tuple(tournament_state::in_progress));
   while (start_iter != start_time_index.end() &&
          start_iter->get_state() == tournament_state::in_progress)
   {
      auto next_iter = std::next(start_iter);
      start_iter->check_for_new_matches_to_start(db);
      start_iter = next_iter;
   }
}

void cancel_expired_tournaments(database& db)
{
   // First, cancel any tournaments that didn't get enough players
   auto& registration_deadline_index = db.get_index_type<tournament_index>().indices().get<by_registration_deadline>();
   // this index is sorted on state and deadline, so the tournaments awaiting registrations with the earliest
   // deadlines will be at the beginning
   while (!registration_deadline_index.empty() &&
          registration_deadline_index.begin()->get_state() == tournament_state::accepting_registrations &&
          registration_deadline_index.begin()->options.registration_deadline <= db.head_block_time())
   {
      const tournament_object& tournament_obj = *registration_deadline_index.begin();
      fc_ilog(fc::logger::get("tournament"),
              "Canceling tournament ${id} because its deadline expired",
              ("id", tournament_obj.id));
      // cancel this tournament
      db.modify(tournament_obj, [&](tournament_object& t) {
         t.on_registration_deadline_passed(db);
      });
   }
}

void start_fully_registered_tournaments(database& db)
{
   // Next, start any tournaments that have enough players and whose start time just arrived
   auto& start_time_index = db.get_index_type<tournament_index>().indices().get<by_start_time>();
   while (1)
   {
      // find the first tournament waiting to start; if its start time has arrived, start it
      auto start_iter = start_time_index.lower_bound(boost::make_tuple(tournament_state::awaiting_start));
      if (start_iter != start_time_index.end() &&
          start_iter->get_state() == tournament_state::awaiting_start && 
          *start_iter->start_time <= db.head_block_time())
      {
         db.modify(*start_iter, [&](tournament_object& t) {
            t.on_start_time_arrived(db);
         });
      }
      else
         break;
   }
}

void initiate_next_round_of_matches(database& db)
{
}

void initiate_next_games(database& db)
{
   // Next, trigger timeouts on any games which have been waiting too long for commit or
   // reveal moves
   auto& next_timeout_index = db.get_index_type<game_index>().indices().get<by_next_timeout>();
   while (1)
   {
      // empty time_points are sorted to the beginning, so upper_bound takes us to the first 
      // non-empty time_point
      auto start_iter = next_timeout_index.upper_bound(boost::make_tuple(optional<time_point_sec>()));
      if (start_iter != next_timeout_index.end() &&
          *start_iter->next_timeout <= db.head_block_time())
      {
         db.modify(*start_iter, [&](game_object& game) {
            game.on_timeout(db);
         });
      }
      else
         break;
   }
}

void database::update_tournaments()
{
   // Process as follows:
   // - Process games
   // - Process matches
   // - Process tournaments
   // - Process matches
   // - Process games
   process_finished_games(*this);
   process_finished_matches(*this);
   cancel_expired_tournaments(*this);
   start_fully_registered_tournaments(*this);
   process_in_progress_tournaments(*this);
   initiate_next_round_of_matches(*this);
   initiate_next_games(*this);
}

void process_settled_betting_markets(database& db, fc::time_point_sec current_block_time)
{
   // after a betting market is graded, it goes through a delay period in which it
   // can be flagged for re-grading.  If it isn't flagged during this interval, 
   // it is automatically settled (paid).  Process these now.
   const auto& betting_market_group_index = db.get_index_type<betting_market_group_object_index>().indices().get<by_settling_time>();

   // this index will be sorted with all bmgs with no settling time set first, followed by 
   // ones with the settling time set by increasing time.  Start at the first bmg with a time set
   auto betting_market_group_iter = betting_market_group_index.upper_bound(fc::optional<fc::time_point_sec>());
   while (betting_market_group_iter != betting_market_group_index.end() && 
          *betting_market_group_iter->settling_time <= current_block_time)
   {
      auto next_iter = std::next(betting_market_group_iter);
      db.settle_betting_market_group(*betting_market_group_iter);
      betting_market_group_iter = next_iter;
   }
}

void database::update_betting_markets(fc::time_point_sec current_block_time)
{
   process_settled_betting_markets(*this, current_block_time);
   remove_completed_events();
}

void database::finalize_expired_offers(){
    try {
       detail::with_skip_flags( *this,
          get_node_properties().skip_flags | skip_authority_check, [&](){
             transaction_evaluation_state cancel_context(this);

             //Cancel expired limit orders
             auto& limit_index = get_index_type<offer_index>().indices().get<by_expiration_date>();
             auto itr = limit_index.begin();
             while( itr != limit_index.end() && itr->offer_expiration_date <= head_block_time() )
             {
                 const offer_object& offer = *itr;
                 ++itr;

                 finalize_offer_operation finalize;
                 finalize.fee_paying_account = offer.issuer;
                 finalize.offer_id = offer.id;
                 finalize.fee = asset( 0, asset_id_type() );
                 finalize.result = offer.bidder ? result_type::Expired : result_type::ExpiredNoBid;

                 cancel_context.skip_fee_schedule_check = true;
                 apply_operation(cancel_context, finalize);
             }
         });
} FC_CAPTURE_AND_RETHROW()}
void database::remove_son_proposal( const proposal_object& proposal )
{ try {
   if( proposal.proposed_transaction.operations.size() == 1 &&
     ( proposal.proposed_transaction.operations.back().which() == operation::tag<son_deregister_operation>::value ||
       proposal.proposed_transaction.operations.back().which() == operation::tag<son_report_down_operation>::value) )
   {
      const auto& son_proposal_idx = get_index_type<son_proposal_index>().indices().get<by_proposal>();
      auto son_proposal_itr = son_proposal_idx.find( proposal.id );
      if( son_proposal_itr == son_proposal_idx.end() ) {
         return;
      }
      remove( *son_proposal_itr );
   }
} FC_CAPTURE_AND_RETHROW( (proposal) ) }

void database::remove_inactive_son_down_proposals( const vector<son_id_type>& son_ids_to_remove )
{
   const auto& son_proposal_idx = get_index_type<son_proposal_index>().indices().get< by_id >();
   std::vector<proposal_id_type> proposals_to_remove;

   for( auto& son_proposal : son_proposal_idx )
   {
      if(son_proposal.proposal_type == son_proposal_type::son_report_down_proposal)
      {
         auto it = std::find(son_ids_to_remove.begin(), son_ids_to_remove.end(), son_proposal.son_id);
         if (it != son_ids_to_remove.end())
         {
            ilog( "Removing inactive proposal ${p} for son ${s}", ("p", son_proposal.proposal_id) ("s",son_proposal.son_id));
            proposals_to_remove.push_back(son_proposal.proposal_id);
         }
      }
   }

   for( auto& proposal_id : proposals_to_remove )
   {
      const auto& proposal_obj = proposal_id(*this);
      remove_son_proposal(proposal_obj);
      remove(proposal_obj);
   }
}

void database::remove_inactive_son_proposals( const vector<son_id_type>& son_ids_to_remove )
{
   remove_inactive_son_down_proposals( son_ids_to_remove );
}

} }