text: 
  // Copyright (c) 2014-2019, The Monero Project
  //
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without modification, are
  // permitted provided that the following conditions are met:
  //
  // 1. Redistributions of source code must retain the above copyright notice, this list of
  //    conditions and the following disclaimer.
  //
  // 2. Redistributions in binary form must reproduce the above copyright notice, this list
  //    of conditions and the following disclaimer in the documentation and/or other
  //    materials provided with the distribution.
  //
  // 3. Neither the name of the copyright holder nor the names of its contributors may be
  //    used to endorse or promote products derived from this software without specific
  //    prior written permission.
  //
  // 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.
  //
  // Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
  
  #include <algorithm>
  #include <boost/filesystem.hpp>
  #include <unordered_set>
  #include <vector>
  
  #include "tx_pool.h"
  #include "cryptonote_tx_utils.h"
  #include "cryptonote_basic/cryptonote_boost_serialization.h"
  #include "cryptonote_config.h"
  #include "blockchain.h"
  #include "blockchain_db/blockchain_db.h"
  #include "common/boost_serialization_helper.h"
  #include "common/int-util.h"
  #include "misc_language.h"
  #include "warnings.h"
  #include "common/perf_timer.h"
  #include "crypto/hash.h"
  
  #undef MONERO_DEFAULT_LOG_CATEGORY
  #define MONERO_DEFAULT_LOG_CATEGORY "txpool"
  
  DISABLE_VS_WARNINGS(4244 4345 4503) //'boost::foreach_detail_::or_' : decorated name length exceeded, name was truncated
  
  using namespace crypto;
  
  namespace cryptonote
  {
    namespace
    {
      //TODO: constants such as these should at least be in the header,
      //      but probably somewhere more accessible to the rest of the
      //      codebase.  As it stands, it is at best nontrivial to test
      //      whether or not changing these parameters (or adding new)
      //      will work correctly.
      time_t const MIN_RELAY_TIME = (60 * 5); // only start re-relaying transactions after that many seconds
      time_t const MAX_RELAY_TIME = (60 * 60 * 4); // at most that many seconds between resends
      float const ACCEPT_THRESHOLD = 1.0f;
  
      // a kind of increasing backoff within min/max bounds
      uint64_t get_relay_delay(time_t now, time_t received)
      {
        time_t d = (now - received + MIN_RELAY_TIME) / MIN_RELAY_TIME * MIN_RELAY_TIME;
        if (d > MAX_RELAY_TIME)
          d = MAX_RELAY_TIME;
        return d;
      }
  
      uint64_t template_accept_threshold(uint64_t amount)
      {
        return amount * ACCEPT_THRESHOLD;
      }
  
      uint64_t get_transaction_weight_limit(uint8_t version)
      {
        // from v8, limit a tx to 50% of the minimum block weight
        if (version >= 8)
          return get_min_block_weight(version) / 2 - CRYPTONOTE_COINBASE_BLOB_RESERVED_SIZE;
        else
          return get_min_block_weight(version) - CRYPTONOTE_COINBASE_BLOB_RESERVED_SIZE;
      }
  
      // This class is meant to create a batch when none currently exists.
      // If a batch exists, it can't be from another thread, since we can
      // only be called with the txpool lock taken, and it is held during
      // the whole prepare/handle/cleanup incoming block sequence.
      class LockedTXN {
      public:
        LockedTXN(Blockchain &b): m_blockchain(b), m_batch(false) {
          m_batch = m_blockchain.get_db().batch_start();
        }
        ~LockedTXN() { try { if (m_batch) { m_blockchain.get_db().batch_stop(); } } catch (const std::exception &e) { MWARNING("LockedTXN dtor filtering exception: " << e.what()); } }
      private:
        Blockchain &m_blockchain;
        bool m_batch;
      };
    }
    //---------------------------------------------------------------------------------
    //---------------------------------------------------------------------------------
    tx_memory_pool::tx_memory_pool(Blockchain& bchs): m_blockchain(bchs), m_txpool_max_weight(DEFAULT_TXPOOL_MAX_WEIGHT), m_txpool_weight(0), m_cookie(0)
    {
  
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::add_tx(transaction &tx, /*const crypto::hash& tx_prefix_hash,*/ const crypto::hash &id, size_t tx_weight, tx_verification_context& tvc, bool kept_by_block, bool relayed, bool do_not_relay, uint8_t version)
    {
      // this should already be called with that lock, but let's make it explicit for clarity
      CRITICAL_REGION_LOCAL(m_transactions_lock);
  
      PERF_TIMER(add_tx);
      if (tx.version == 0)
      {
        // v0 never accepted
        LOG_PRINT_L1("transaction version 0 is invalid");
        tvc.m_verifivation_failed = true;
        return false;
      }
  
      // we do not accept transactions that timed out before, unless they're
      // kept_by_block
      if (!kept_by_block && m_timed_out_transactions.find(id) != m_timed_out_transactions.end())
      {
        // not clear if we should set that, since verifivation (sic) did not fail before, since
        // the tx was accepted before timing out.
        tvc.m_verifivation_failed = true;
        return false;
      }
  
      if(!check_inputs_types_supported(tx))
      {
        tvc.m_verifivation_failed = true;
        tvc.m_invalid_input = true;
        return false;
      }
  
      // fee per kilobyte, size rounded up.
      uint64_t fee;
  
      if (tx.version == 1)
      {
        uint64_t inputs_amount = 0;
        if(!get_inputs_money_amount(tx, inputs_amount))
        {
          tvc.m_verifivation_failed = true;
          return false;
        }
  
        uint64_t outputs_amount = get_outs_money_amount(tx);
        if(outputs_amount > inputs_amount)
        {
          LOG_PRINT_L1("transaction use more money than it has: use " << print_money(outputs_amount) << ", have " << print_money(inputs_amount));
          tvc.m_verifivation_failed = true;
          tvc.m_overspend = true;
          return false;
        }
        else if(outputs_amount == inputs_amount)
        {
          LOG_PRINT_L1("transaction fee is zero: outputs_amount == inputs_amount, rejecting.");
          tvc.m_verifivation_failed = true;
          tvc.m_fee_too_low = true;
          return false;
        }
  
        fee = inputs_amount - outputs_amount;
      }
      else
      {
        fee = tx.rct_signatures.txnFee;
      }
  
      if (!kept_by_block && !m_blockchain.check_fee(tx_weight, fee))
      {
        tvc.m_verifivation_failed = true;
        tvc.m_fee_too_low = true;
        return false;
      }
  
      size_t tx_weight_limit = get_transaction_weight_limit(version);
      if ((!kept_by_block || version >= HF_VERSION_PER_BYTE_FEE) && tx_weight > tx_weight_limit)
      {
        LOG_PRINT_L1("transaction is too heavy: " << tx_weight << " bytes, maximum weight: " << tx_weight_limit);
        tvc.m_verifivation_failed = true;
        tvc.m_too_big = true;
        return false;
      }
  
      // if the transaction came from a block popped from the chain,
      // don't check if we have its key images as spent.
      // TODO: Investigate why not?
      if(!kept_by_block)
      {
        if(have_tx_keyimges_as_spent(tx))
        {
          mark_double_spend(tx);
          LOG_PRINT_L1("Transaction with id= "<< id << " used already spent key images");
          tvc.m_verifivation_failed = true;
          tvc.m_double_spend = true;
          return false;
        }
      }
  
      if (!m_blockchain.check_tx_outputs(tx, tvc))
      {
        LOG_PRINT_L1("Transaction with id= "<< id << " has at least one invalid output");
        tvc.m_verifivation_failed = true;
        tvc.m_invalid_output = true;
        return false;
      }
  
      // assume failure during verification steps until success is certain
      tvc.m_verifivation_failed = true;
  
      time_t receive_time = time(nullptr);
  
      crypto::hash max_used_block_id = null_hash;
      uint64_t max_used_block_height = 0;
      cryptonote::txpool_tx_meta_t meta;
      bool ch_inp_res = check_tx_inputs([&tx]()->cryptonote::transaction&{ return tx; }, id, max_used_block_height, max_used_block_id, tvc, kept_by_block);
      if(!ch_inp_res)
      {
        // if the transaction was valid before (kept_by_block), then it
        // may become valid again, so ignore the failed inputs check.
        if(kept_by_block)
        {
          meta.weight = tx_weight;
          meta.fee = fee;
          meta.max_used_block_id = null_hash;
          meta.max_used_block_height = 0;
          meta.last_failed_height = 0;
          meta.last_failed_id = null_hash;
          meta.kept_by_block = kept_by_block;
          meta.receive_time = receive_time;
          meta.last_relayed_time = time(NULL);
          meta.relayed = relayed;
          meta.do_not_relay = do_not_relay;
          meta.double_spend_seen = have_tx_keyimges_as_spent(tx);
          meta.bf_padding = 0;
          memset(meta.padding, 0, sizeof(meta.padding));
          try
          {
            CRITICAL_REGION_LOCAL1(m_blockchain);
            LockedTXN lock(m_blockchain);
            m_blockchain.add_txpool_tx(tx, meta);
            if (!insert_key_images(tx, kept_by_block))
              return false;
            m_txs_by_fee_and_receive_time.emplace(std::pair<double, std::time_t>(fee / (double)tx_weight, receive_time), id);
          }
          catch (const std::exception &e)
          {
            MERROR("transaction already exists at inserting in memory pool: " << e.what());
            return false;
          }
          tvc.m_verifivation_impossible = true;
          tvc.m_added_to_pool = true;
        }else
        {
          LOG_PRINT_L1("tx used wrong inputs, rejected");
          tvc.m_verifivation_failed = true;
          tvc.m_invalid_input = true;
          return false;
        }
      }else
      {
        //update transactions container
        meta.weight = tx_weight;
        meta.kept_by_block = kept_by_block;
        meta.fee = fee;
        meta.max_used_block_id = max_used_block_id;
        meta.max_used_block_height = max_used_block_height;
        meta.last_failed_height = 0;
        meta.last_failed_id = null_hash;
        meta.receive_time = receive_time;
        meta.last_relayed_time = time(NULL);
        meta.relayed = relayed;
        meta.do_not_relay = do_not_relay;
        meta.double_spend_seen = false;
        meta.bf_padding = 0;
        memset(meta.padding, 0, sizeof(meta.padding));
  
        try
        {
          CRITICAL_REGION_LOCAL1(m_blockchain);
          LockedTXN lock(m_blockchain);
          m_blockchain.remove_txpool_tx(get_transaction_hash(tx));
          m_blockchain.add_txpool_tx(tx, meta);
          if (!insert_key_images(tx, kept_by_block))
            return false;
          m_txs_by_fee_and_receive_time.emplace(std::pair<double, std::time_t>(fee / (double)tx_weight, receive_time), id);
        }
        catch (const std::exception &e)
        {
          MERROR("internal error: transaction already exists at inserting in memory pool: " << e.what());
          return false;
        }
        tvc.m_added_to_pool = true;
  
        if(meta.fee > 0 && !do_not_relay)
          tvc.m_should_be_relayed = true;
      }
  
      tvc.m_verifivation_failed = false;
      m_txpool_weight += tx_weight;
  
      ++m_cookie;
  
      MINFO("Transaction added to pool: txid " << id << " weight: " << tx_weight << " fee/byte: " << (fee / (double)tx_weight));
  
      prune(m_txpool_max_weight);
  
      return true;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::add_tx(transaction &tx, tx_verification_context& tvc, bool keeped_by_block, bool relayed, bool do_not_relay, uint8_t version)
    {
      crypto::hash h = null_hash;
      size_t blob_size = 0;
      if (!get_transaction_hash(tx, h, blob_size) || blob_size == 0)
        return false;
      return add_tx(tx, h, get_transaction_weight(tx, blob_size), tvc, keeped_by_block, relayed, do_not_relay, version);
    }
    //---------------------------------------------------------------------------------
    size_t tx_memory_pool::get_txpool_weight() const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      return m_txpool_weight;
    }
    //---------------------------------------------------------------------------------
    void tx_memory_pool::set_txpool_max_weight(size_t bytes)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      m_txpool_max_weight = bytes;
    }
    //---------------------------------------------------------------------------------
    void tx_memory_pool::prune(size_t bytes)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      if (bytes == 0)
        bytes = m_txpool_max_weight;
      CRITICAL_REGION_LOCAL1(m_blockchain);
      LockedTXN lock(m_blockchain);
      bool changed = false;
  
      // this will never remove the first one, but we don't care
      auto it = --m_txs_by_fee_and_receive_time.end();
      while (it != m_txs_by_fee_and_receive_time.begin())
      {
        if (m_txpool_weight <= bytes)
          break;
        try
        {
          const crypto::hash &txid = it->second;
          txpool_tx_meta_t meta;
          if (!m_blockchain.get_txpool_tx_meta(txid, meta))
          {
            MERROR("Failed to find tx in txpool");
            return;
          }
          // don't prune the kept_by_block ones, they're likely added because we're adding a block with those
          if (meta.kept_by_block)
          {
            --it;
            continue;
          }
          cryptonote::blobdata txblob = m_blockchain.get_txpool_tx_blob(txid);
          cryptonote::transaction tx;
          if (!parse_and_validate_tx_from_blob(txblob, tx))
          {
            MERROR("Failed to parse tx from txpool");
            return;
          }
          // remove first, in case this throws, so key images aren't removed
          MINFO("Pruning tx " << txid << " from txpool: weight: " << it->first.second << ", fee/byte: " << it->first.first);
          m_blockchain.remove_txpool_tx(txid);
          m_txpool_weight -= it->first.second;
          remove_transaction_keyimages(tx);
          MINFO("Pruned tx " << txid << " from txpool: weight: " << it->first.second << ", fee/byte: " << it->first.first);
          m_txs_by_fee_and_receive_time.erase(it--);
          changed = true;
        }
        catch (const std::exception &e)
        {
          MERROR("Error while pruning txpool: " << e.what());
          return;
        }
      }
      if (changed)
        ++m_cookie;
      if (m_txpool_weight > bytes)
        MINFO("Pool weight after pruning is larger than limit: " << m_txpool_weight << "/" << bytes);
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::insert_key_images(const transaction &tx, bool kept_by_block)
    {
      for(const auto& in: tx.vin)
      {
        const crypto::hash id = get_transaction_hash(tx);
        CHECKED_GET_SPECIFIC_VARIANT(in, const txin_to_key, txin, false);
        std::unordered_set<crypto::hash>& kei_image_set = m_spent_key_images[txin.k_image];
        CHECK_AND_ASSERT_MES(kept_by_block || kei_image_set.size() == 0, false, "internal error: kept_by_block=" << kept_by_block
                                            << ",  kei_image_set.size()=" << kei_image_set.size() << ENDL << "txin.k_image=" << txin.k_image << ENDL
                                            << "tx_id=" << id );
        auto ins_res = kei_image_set.insert(id);
        CHECK_AND_ASSERT_MES(ins_res.second, false, "internal error: try to insert duplicate iterator in key_image set");
      }
      ++m_cookie;
      return true;
    }
    //---------------------------------------------------------------------------------
    //FIXME: Can return early before removal of all of the key images.
    //       At the least, need to make sure that a false return here
    //       is treated properly.  Should probably not return early, however.
    bool tx_memory_pool::remove_transaction_keyimages(const transaction& tx)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      // ND: Speedup
      // 1. Move transaction hash calcuation outside of loop. ._.
      crypto::hash actual_hash = get_transaction_hash(tx);
      for(const txin_v& vi: tx.vin)
      {
        CHECKED_GET_SPECIFIC_VARIANT(vi, const txin_to_key, txin, false);
        auto it = m_spent_key_images.find(txin.k_image);
        CHECK_AND_ASSERT_MES(it != m_spent_key_images.end(), false, "failed to find transaction input in key images. img=" << txin.k_image << ENDL
                                      << "transaction id = " << get_transaction_hash(tx));
        std::unordered_set<crypto::hash>& key_image_set =  it->second;
        CHECK_AND_ASSERT_MES(key_image_set.size(), false, "empty key_image set, img=" << txin.k_image << ENDL
          << "transaction id = " << actual_hash);
  
        auto it_in_set = key_image_set.find(actual_hash);
        CHECK_AND_ASSERT_MES(it_in_set != key_image_set.end(), false, "transaction id not found in key_image set, img=" << txin.k_image << ENDL
          << "transaction id = " << actual_hash);
        key_image_set.erase(it_in_set);
        if(!key_image_set.size())
        {
          //it is now empty hash container for this key_image
          m_spent_key_images.erase(it);
        }
  
      }
      ++m_cookie;
      return true;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::take_tx(const crypto::hash &id, transaction &tx, size_t& tx_weight, uint64_t& fee, bool &relayed, bool &do_not_relay, bool &double_spend_seen)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
  
      auto sorted_it = find_tx_in_sorted_container(id);
      if (sorted_it == m_txs_by_fee_and_receive_time.end())
        return false;
  
      try
      {
        LockedTXN lock(m_blockchain);
        txpool_tx_meta_t meta;
        if (!m_blockchain.get_txpool_tx_meta(id, meta))
        {
          MERROR("Failed to find tx in txpool");
          return false;
        }
        cryptonote::blobdata txblob = m_blockchain.get_txpool_tx_blob(id);
        if (!parse_and_validate_tx_from_blob(txblob, tx))
        {
          MERROR("Failed to parse tx from txpool");
          return false;
        }
        tx_weight = meta.weight;
        fee = meta.fee;
        relayed = meta.relayed;
        do_not_relay = meta.do_not_relay;
        double_spend_seen = meta.double_spend_seen;
  
        // remove first, in case this throws, so key images aren't removed
        m_blockchain.remove_txpool_tx(id);
        m_txpool_weight -= tx_weight;
        remove_transaction_keyimages(tx);
      }
      catch (const std::exception &e)
      {
        MERROR("Failed to remove tx from txpool: " << e.what());
        return false;
      }
  
      m_txs_by_fee_and_receive_time.erase(sorted_it);
      ++m_cookie;
      return true;
    }
    //---------------------------------------------------------------------------------
    void tx_memory_pool::on_idle()
    {
      m_remove_stuck_tx_interval.do_call([this](){return remove_stuck_transactions();});
    }
    //---------------------------------------------------------------------------------
    sorted_tx_container::iterator tx_memory_pool::find_tx_in_sorted_container(const crypto::hash& id) const
    {
      return std::find_if( m_txs_by_fee_and_receive_time.begin(), m_txs_by_fee_and_receive_time.end()
                         , [&](const sorted_tx_container::value_type& a){
                           return a.second == id;
                         }
      );
    }
    //---------------------------------------------------------------------------------
    //TODO: investigate whether boolean return is appropriate
    bool tx_memory_pool::remove_stuck_transactions()
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      std::unordered_set<crypto::hash> remove;
      m_blockchain.for_all_txpool_txes([this, &remove](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata*) {
        uint64_t tx_age = time(nullptr) - meta.receive_time;
  
        if((tx_age > CRYPTONOTE_MEMPOOL_TX_LIVETIME && !meta.kept_by_block) ||
           (tx_age > CRYPTONOTE_MEMPOOL_TX_FROM_ALT_BLOCK_LIVETIME && meta.kept_by_block) )
        {
          LOG_PRINT_L1("Tx " << txid << " removed from tx pool due to outdated, age: " << tx_age );
          auto sorted_it = find_tx_in_sorted_container(txid);
          if (sorted_it == m_txs_by_fee_and_receive_time.end())
          {
            LOG_PRINT_L1("Removing tx " << txid << " from tx pool, but it was not found in the sorted txs container!");
          }
          else
          {
            m_txs_by_fee_and_receive_time.erase(sorted_it);
          }
          m_timed_out_transactions.insert(txid);
          remove.insert(txid);
        }
        return true;
      }, false);
  
      if (!remove.empty())
      {
        LockedTXN lock(m_blockchain);
        for (const crypto::hash &txid: remove)
        {
          try
          {
            cryptonote::blobdata bd = m_blockchain.get_txpool_tx_blob(txid);
            cryptonote::transaction tx;
            if (!parse_and_validate_tx_from_blob(bd, tx))
            {
              MERROR("Failed to parse tx from txpool");
              // continue
            }
            else
            {
              // remove first, so we only remove key images if the tx removal succeeds
              m_blockchain.remove_txpool_tx(txid);
              m_txpool_weight -= get_transaction_weight(tx, bd.size());
              remove_transaction_keyimages(tx);
            }
          }
          catch (const std::exception &e)
          {
            MWARNING("Failed to remove stuck transaction: " << txid);
            // ignore error
          }
        }
        ++m_cookie;
      }
      return true;
    }
    //---------------------------------------------------------------------------------
    //TODO: investigate whether boolean return is appropriate
    bool tx_memory_pool::get_relayable_transactions(std::vector<std::pair<crypto::hash, cryptonote::blobdata>> &txs) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      const uint64_t now = time(NULL);
      txs.reserve(m_blockchain.get_txpool_tx_count());
      m_blockchain.for_all_txpool_txes([this, now, &txs](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata *){
        // 0 fee transactions are never relayed
        if(meta.fee > 0 && !meta.do_not_relay && now - meta.last_relayed_time > get_relay_delay(now, meta.receive_time))
        {
          // if the tx is older than half the max lifetime, we don't re-relay it, to avoid a problem
          // mentioned by smooth where nodes would flush txes at slightly different times, causing
          // flushed txes to be re-added when received from a node which was just about to flush it
          uint64_t max_age = meta.kept_by_block ? CRYPTONOTE_MEMPOOL_TX_FROM_ALT_BLOCK_LIVETIME : CRYPTONOTE_MEMPOOL_TX_LIVETIME;
          if (now - meta.receive_time <= max_age / 2)
          {
            try
            {
              cryptonote::blobdata bd = m_blockchain.get_txpool_tx_blob(txid);
              txs.push_back(std::make_pair(txid, bd));
            }
            catch (const std::exception &e)
            {
              MERROR("Failed to get transaction blob from db");
              // ignore error
            }
          }
        }
        return true;
      }, false);
      return true;
    }
    //---------------------------------------------------------------------------------
    void tx_memory_pool::set_relayed(const std::vector<std::pair<crypto::hash, cryptonote::blobdata>> &txs)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      const time_t now = time(NULL);
      LockedTXN lock(m_blockchain);
      for (auto it = txs.begin(); it != txs.end(); ++it)
      {
        try
        {
          txpool_tx_meta_t meta;
          if (m_blockchain.get_txpool_tx_meta(it->first, meta))
          {
            meta.relayed = true;
            meta.last_relayed_time = now;
            m_blockchain.update_txpool_tx(it->first, meta);
          }
        }
        catch (const std::exception &e)
        {
          MERROR("Failed to update txpool transaction metadata: " << e.what());
          // continue
        }
      }
    }
    //---------------------------------------------------------------------------------
    size_t tx_memory_pool::get_transactions_count(bool include_unrelayed_txes) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      return m_blockchain.get_txpool_tx_count(include_unrelayed_txes);
    }
    //---------------------------------------------------------------------------------
    void tx_memory_pool::get_transactions(std::vector<transaction>& txs, bool include_unrelayed_txes) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      txs.reserve(m_blockchain.get_txpool_tx_count(include_unrelayed_txes));
      m_blockchain.for_all_txpool_txes([&txs](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata *bd){
        transaction tx;
        if (!parse_and_validate_tx_from_blob(*bd, tx))
        {
          MERROR("Failed to parse tx from txpool");
          // continue
          return true;
        }
        txs.push_back(tx);
        return true;
      }, true, include_unrelayed_txes);
    }
    //------------------------------------------------------------------
    void tx_memory_pool::get_transaction_hashes(std::vector<crypto::hash>& txs, bool include_unrelayed_txes) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      txs.reserve(m_blockchain.get_txpool_tx_count(include_unrelayed_txes));
      m_blockchain.for_all_txpool_txes([&txs](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata *bd){
        txs.push_back(txid);
        return true;
      }, false, include_unrelayed_txes);
    }
    //------------------------------------------------------------------
    void tx_memory_pool::get_transaction_backlog(std::vector<tx_backlog_entry>& backlog, bool include_unrelayed_txes) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      const uint64_t now = time(NULL);
      backlog.reserve(m_blockchain.get_txpool_tx_count(include_unrelayed_txes));
      m_blockchain.for_all_txpool_txes([&backlog, now](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata *bd){
        backlog.push_back({meta.weight, meta.fee, meta.receive_time - now});
        return true;
      }, false, include_unrelayed_txes);
    }
    //------------------------------------------------------------------
    void tx_memory_pool::get_transaction_stats(struct txpool_stats& stats, bool include_unrelayed_txes) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      const uint64_t now = time(NULL);
      std::map<uint64_t, txpool_histo> agebytes;
      stats.txs_total = m_blockchain.get_txpool_tx_count(include_unrelayed_txes);
      std::vector<uint32_t> weights;
      weights.reserve(stats.txs_total);
      m_blockchain.for_all_txpool_txes([&stats, &weights, now, &agebytes](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata *bd){
        weights.push_back(meta.weight);
        stats.bytes_total += meta.weight;
        if (!stats.bytes_min || meta.weight < stats.bytes_min)
          stats.bytes_min = meta.weight;
        if (meta.weight > stats.bytes_max)
          stats.bytes_max = meta.weight;
        if (!meta.relayed)
          stats.num_not_relayed++;
        stats.fee_total += meta.fee;
        if (!stats.oldest || meta.receive_time < stats.oldest)
          stats.oldest = meta.receive_time;
        if (meta.receive_time < now - 600)
          stats.num_10m++;
        if (meta.last_failed_height)
          stats.num_failing++;
        uint64_t age = now - meta.receive_time + (now == meta.receive_time);
        agebytes[age].txs++;
        agebytes[age].bytes += meta.weight;
        if (meta.double_spend_seen)
          ++stats.num_double_spends;
        return true;
        }, false, include_unrelayed_txes);
      stats.bytes_med = epee::misc_utils::median(weights);
      if (stats.txs_total > 1)
      {
        /* looking for 98th percentile */
        size_t end = stats.txs_total * 0.02;
        uint64_t delta, factor;
        std::map<uint64_t, txpool_histo>::iterator it, i2;
        if (end)
        {
          /* If enough txs, spread the first 98% of results across
           * the first 9 bins, drop final 2% in last bin.
           */
          it=agebytes.end();
          for (size_t n=0; n <= end; n++, it--);
          stats.histo_98pc = it->first;
          factor = 9;
          delta = it->first;
          stats.histo.resize(10);
        } else
        {
          /* If not enough txs, don't reserve the last slot;
           * spread evenly across all 10 bins.
           */
          stats.histo_98pc = 0;
          it = agebytes.end();
          factor = stats.txs_total > 9 ? 10 : stats.txs_total;
          delta = now - stats.oldest;
          stats.histo.resize(factor);
        }
        if (!delta)
          delta = 1;
        for (i2 = agebytes.begin(); i2 != it; i2++)
        {
          size_t i = (i2->first * factor - 1) / delta;
          stats.histo[i].txs += i2->second.txs;
          stats.histo[i].bytes += i2->second.bytes;
        }
        for (; i2 != agebytes.end(); i2++)
        {
          stats.histo[factor].txs += i2->second.txs;
          stats.histo[factor].bytes += i2->second.bytes;
        }
      }
    }
    //------------------------------------------------------------------
    //TODO: investigate whether boolean return is appropriate
    bool tx_memory_pool::get_transactions_and_spent_keys_info(std::vector<tx_info>& tx_infos, std::vector<spent_key_image_info>& key_image_infos, bool include_sensitive_data) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      tx_infos.reserve(m_blockchain.get_txpool_tx_count());
      key_image_infos.reserve(m_blockchain.get_txpool_tx_count());
      m_blockchain.for_all_txpool_txes([&tx_infos, key_image_infos, include_sensitive_data](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata *bd){
        tx_info txi;
        txi.id_hash = epee::string_tools::pod_to_hex(txid);
        txi.tx_blob = *bd;
        transaction tx;
        if (!parse_and_validate_tx_from_blob(*bd, tx))
        {
          MERROR("Failed to parse tx from txpool");
          // continue
          return true;
        }
        txi.tx_json = obj_to_json_str(tx);
        txi.blob_size = bd->size();
        txi.weight = meta.weight;
        txi.fee = meta.fee;
        txi.kept_by_block = meta.kept_by_block;
        txi.max_used_block_height = meta.max_used_block_height;
        txi.max_used_block_id_hash = epee::string_tools::pod_to_hex(meta.max_used_block_id);
        txi.last_failed_height = meta.last_failed_height;
        txi.last_failed_id_hash = epee::string_tools::pod_to_hex(meta.last_failed_id);
        // In restricted mode we do not include this data:
        txi.receive_time = include_sensitive_data ? meta.receive_time : 0;
        txi.relayed = meta.relayed;
        // In restricted mode we do not include this data:
        txi.last_relayed_time = include_sensitive_data ? meta.last_relayed_time : 0;
        txi.do_not_relay = meta.do_not_relay;
        txi.double_spend_seen = meta.double_spend_seen;
        tx_infos.push_back(txi);
        return true;
      }, true, include_sensitive_data);
  
      txpool_tx_meta_t meta;
      for (const key_images_container::value_type& kee : m_spent_key_images) {
        const crypto::key_image& k_image = kee.first;
        const std::unordered_set<crypto::hash>& kei_image_set = kee.second;
        spent_key_image_info ki;
        ki.id_hash = epee::string_tools::pod_to_hex(k_image);
        for (const crypto::hash& tx_id_hash : kei_image_set)
        {
          if (!include_sensitive_data)
          {
            try
            {
              if (!m_blockchain.get_txpool_tx_meta(tx_id_hash, meta))
              {
                MERROR("Failed to get tx meta from txpool");
                return false;
              }
              if (!meta.relayed)
                // Do not include that transaction if in restricted mode and it's not relayed
                continue;
            }
            catch (const std::exception &e)
            {
              MERROR("Failed to get tx meta from txpool: " << e.what());
              return false;
            }
          }
          ki.txs_hashes.push_back(epee::string_tools::pod_to_hex(tx_id_hash));
        }
        // Only return key images for which we have at least one tx that we can show for them
        if (!ki.txs_hashes.empty())
          key_image_infos.push_back(ki);
      }
      return true;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::get_pool_for_rpc(std::vector<cryptonote::rpc::tx_in_pool>& tx_infos, cryptonote::rpc::key_images_with_tx_hashes& key_image_infos) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      tx_infos.reserve(m_blockchain.get_txpool_tx_count());
      key_image_infos.reserve(m_blockchain.get_txpool_tx_count());
      m_blockchain.for_all_txpool_txes([&tx_infos, key_image_infos](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata *bd){
        cryptonote::rpc::tx_in_pool txi;
        txi.tx_hash = txid;
        transaction tx;
        if (!parse_and_validate_tx_from_blob(*bd, tx))
        {
          MERROR("Failed to parse tx from txpool");
          // continue
          return true;
        }
        txi.tx = tx;
        txi.blob_size = bd->size();
        txi.weight = meta.weight;
        txi.fee = meta.fee;
        txi.kept_by_block = meta.kept_by_block;
        txi.max_used_block_height = meta.max_used_block_height;
        txi.max_used_block_hash = meta.max_used_block_id;
        txi.last_failed_block_height = meta.last_failed_height;
        txi.last_failed_block_hash = meta.last_failed_id;
        txi.receive_time = meta.receive_time;
        txi.relayed = meta.relayed;
        txi.last_relayed_time = meta.last_relayed_time;
        txi.do_not_relay = meta.do_not_relay;
        txi.double_spend_seen = meta.double_spend_seen;
        tx_infos.push_back(txi);
        return true;
      }, true, false);
  
      for (const key_images_container::value_type& kee : m_spent_key_images) {
        std::vector<crypto::hash> tx_hashes;
        const std::unordered_set<crypto::hash>& kei_image_set = kee.second;
        for (const crypto::hash& tx_id_hash : kei_image_set)
        {
          tx_hashes.push_back(tx_id_hash);
        }
  
        const crypto::key_image& k_image = kee.first;
        key_image_infos[k_image] = tx_hashes;
      }
      return true;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::check_for_key_images(const std::vector<crypto::key_image>& key_images, std::vector<bool> spent) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
  
      spent.clear();
  
      for (const auto& image : key_images)
      {
        spent.push_back(m_spent_key_images.find(image) == m_spent_key_images.end() ? false : true);
      }
  
      return true;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::get_transaction(const crypto::hash& id, cryptonote::blobdata& txblob) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      try
      {
        return m_blockchain.get_txpool_tx_blob(id, txblob);
      }
      catch (const std::exception &e)
      {
        return false;
      }
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::on_blockchain_inc(uint64_t new_block_height, const crypto::hash& top_block_id)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      m_input_cache.clear();
      return true;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::on_blockchain_dec(uint64_t new_block_height, const crypto::hash& top_block_id)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      m_input_cache.clear();
      return true;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::have_tx(const crypto::hash &id) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      return m_blockchain.get_db().txpool_has_tx(id);
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::have_tx_keyimges_as_spent(const transaction& tx) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      for(const auto& in: tx.vin)
      {
        CHECKED_GET_SPECIFIC_VARIANT(in, const txin_to_key, tokey_in, true);//should never fail
        if(have_tx_keyimg_as_spent(tokey_in.k_image))
           return true;
      }
      return false;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::have_tx_keyimg_as_spent(const crypto::key_image& key_im) const
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      return m_spent_key_images.end() != m_spent_key_images.find(key_im);
    }
    //---------------------------------------------------------------------------------
    void tx_memory_pool::lock() const
    {
      m_transactions_lock.lock();
    }
    //---------------------------------------------------------------------------------
    void tx_memory_pool::unlock() const
    {
      m_transactions_lock.unlock();
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::check_tx_inputs(const std::function<cryptonote::transaction&(void)> &get_tx, const crypto::hash &txid, uint64_t &max_used_block_height, crypto::hash &max_used_block_id, tx_verification_context &tvc, bool kept_by_block) const
    {
      if (!kept_by_block)
      {
        const std::unordered_map<crypto::hash, std::tuple<bool, tx_verification_context, uint64_t, crypto::hash>>::const_iterator i = m_input_cache.find(txid);
        if (i != m_input_cache.end())
        {
          max_used_block_height = std::get<2>(i->second);
          max_used_block_id = std::get<3>(i->second);
          tvc = std::get<1>(i->second);
          return std::get<0>(i->second);
        }
      }
      bool ret = m_blockchain.check_tx_inputs(get_tx(), max_used_block_height, max_used_block_id, tvc, kept_by_block);
      if (!kept_by_block)
        m_input_cache.insert(std::make_pair(txid, std::make_tuple(ret, tvc, max_used_block_height, max_used_block_id)));
      return ret;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::is_transaction_ready_to_go(txpool_tx_meta_t& txd, const crypto::hash &txid, const cryptonote::blobdata &txblob, transaction &tx) const
    {
      struct transction_parser
      {
        transction_parser(const cryptonote::blobdata &txblob, transaction &tx): txblob(txblob), tx(tx), parsed(false) {}
        cryptonote::transaction &operator()()
        {
          if (!parsed)
          {
            if (!parse_and_validate_tx_from_blob(txblob, tx))
              throw std::runtime_error("failed to parse transaction blob");
            parsed = true;
          }
          return tx;
        }
        const cryptonote::blobdata &txblob;
        transaction &tx;
        bool parsed;
      } lazy_tx(txblob, tx);
  
      //not the best implementation at this time, sorry :(
      //check is ring_signature already checked ?
      if(txd.max_used_block_id == null_hash)
      {//not checked, lets try to check
  
        if(txd.last_failed_id != null_hash && m_blockchain.get_current_blockchain_height() > txd.last_failed_height && txd.last_failed_id == m_blockchain.get_block_id_by_height(txd.last_failed_height))
          return false;//we already sure that this tx is broken for this height
  
        tx_verification_context tvc;
        if(!check_tx_inputs([&lazy_tx]()->cryptonote::transaction&{ return lazy_tx(); }, txid, txd.max_used_block_height, txd.max_used_block_id, tvc))
        {
          txd.last_failed_height = m_blockchain.get_current_blockchain_height()-1;
          txd.last_failed_id = m_blockchain.get_block_id_by_height(txd.last_failed_height);
          return false;
        }
      }else
      {
        if(txd.max_used_block_height >= m_blockchain.get_current_blockchain_height())
          return false;
        if(true)
        {
          //if we already failed on this height and id, skip actual ring signature check
          if(txd.last_failed_id == m_blockchain.get_block_id_by_height(txd.last_failed_height))
            return false;
          //check ring signature again, it is possible (with very small chance) that this transaction become again valid
          tx_verification_context tvc;
          if(!check_tx_inputs([&lazy_tx]()->cryptonote::transaction&{ return lazy_tx(); }, txid, txd.max_used_block_height, txd.max_used_block_id, tvc))
          {
            txd.last_failed_height = m_blockchain.get_current_blockchain_height()-1;
            txd.last_failed_id = m_blockchain.get_block_id_by_height(txd.last_failed_height);
            return false;
          }
        }
      }
      //if we here, transaction seems valid, but, anyway, check for key_images collisions with blockchain, just to be sure
      if(m_blockchain.have_tx_keyimges_as_spent(lazy_tx()))
      {
        txd.double_spend_seen = true;
        return false;
      }
  
      //transaction is ok.
      return true;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::have_key_images(const std::unordered_set<crypto::key_image>& k_images, const transaction& tx)
    {
      for(size_t i = 0; i!= tx.vin.size(); i++)
      {
        CHECKED_GET_SPECIFIC_VARIANT(tx.vin[i], const txin_to_key, itk, false);
        if(k_images.count(itk.k_image))
          return true;
      }
      return false;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::append_key_images(std::unordered_set<crypto::key_image>& k_images, const transaction& tx)
    {
      for(size_t i = 0; i!= tx.vin.size(); i++)
      {
        CHECKED_GET_SPECIFIC_VARIANT(tx.vin[i], const txin_to_key, itk, false);
        auto i_res = k_images.insert(itk.k_image);
        CHECK_AND_ASSERT_MES(i_res.second, false, "internal error: key images pool cache - inserted duplicate image in set: " << itk.k_image);
      }
      return true;
    }
    //---------------------------------------------------------------------------------
    void tx_memory_pool::mark_double_spend(const transaction &tx)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      bool changed = false;
      LockedTXN lock(m_blockchain);
      for(size_t i = 0; i!= tx.vin.size(); i++)
      {
        CHECKED_GET_SPECIFIC_VARIANT(tx.vin[i], const txin_to_key, itk, void());
        const key_images_container::const_iterator it = m_spent_key_images.find(itk.k_image);
        if (it != m_spent_key_images.end())
        {
          for (const crypto::hash &txid: it->second)
          {
            txpool_tx_meta_t meta;
            if (!m_blockchain.get_txpool_tx_meta(txid, meta))
            {
              MERROR("Failed to find tx meta in txpool");
              // continue, not fatal
              continue;
            }
            if (!meta.double_spend_seen)
            {
              MDEBUG("Marking " << txid << " as double spending " << itk.k_image);
              meta.double_spend_seen = true;
              changed = true;
              try
              {
                m_blockchain.update_txpool_tx(txid, meta);
              }
              catch (const std::exception &e)
              {
                MERROR("Failed to update tx meta: " << e.what());
                // continue, not fatal
              }
            }
          }
        }
      }
      if (changed)
        ++m_cookie;
    }
    //---------------------------------------------------------------------------------
    std::string tx_memory_pool::print_pool(bool short_format) const
    {
      std::stringstream ss;
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      m_blockchain.for_all_txpool_txes([&ss, short_format](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata *txblob) {
        ss << "id: " << txid << std::endl;
        if (!short_format) {
          cryptonote::transaction tx;
          if (!parse_and_validate_tx_from_blob(*txblob, tx))
          {
            MERROR("Failed to parse tx from txpool");
            return true; // continue
          }
          ss << obj_to_json_str(tx) << std::endl;
        }
        ss << "blob_size: " << (short_format ? "-" : std::to_string(txblob->size())) << std::endl
          << "weight: " << meta.weight << std::endl
          << "fee: " << print_money(meta.fee) << std::endl
          << "kept_by_block: " << (meta.kept_by_block ? 'T' : 'F') << std::endl
          << "double_spend_seen: " << (meta.double_spend_seen ? 'T' : 'F') << std::endl
          << "max_used_block_height: " << meta.max_used_block_height << std::endl
          << "max_used_block_id: " << meta.max_used_block_id << std::endl
          << "last_failed_height: " << meta.last_failed_height << std::endl
          << "last_failed_id: " << meta.last_failed_id << std::endl;
        return true;
      }, !short_format);
  
      return ss.str();
    }
    //---------------------------------------------------------------------------------
    //TODO: investigate whether boolean return is appropriate
    bool tx_memory_pool::fill_block_template(block &bl, size_t median_weight, uint64_t already_generated_coins, size_t &total_weight, uint64_t &fee, uint64_t &expected_reward, uint8_t version)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
  
      uint64_t best_coinbase = 0, coinbase = 0;
      total_weight = 0;
      fee = 0;
      
      //baseline empty block
      get_block_reward(median_weight, total_weight, already_generated_coins, best_coinbase, version);
  
  
      size_t max_total_weight_pre_v5 = (130 * median_weight) / 100 - CRYPTONOTE_COINBASE_BLOB_RESERVED_SIZE;
      size_t max_total_weight_v5 = 2 * median_weight - CRYPTONOTE_COINBASE_BLOB_RESERVED_SIZE;
      size_t max_total_weight = version >= 5 ? max_total_weight_v5 : max_total_weight_pre_v5;
      std::unordered_set<crypto::key_image> k_images;
  
      LOG_PRINT_L2("Filling block template, median weight " << median_weight << ", " << m_txs_by_fee_and_receive_time.size() << " txes in the pool");
  
      LockedTXN lock(m_blockchain);
  
      auto sorted_it = m_txs_by_fee_and_receive_time.begin();
      for (; sorted_it != m_txs_by_fee_and_receive_time.end(); ++sorted_it)
      {
        txpool_tx_meta_t meta;
        if (!m_blockchain.get_txpool_tx_meta(sorted_it->second, meta))
        {
          MERROR("  failed to find tx meta");
          continue;
        }
        LOG_PRINT_L2("Considering " << sorted_it->second << ", weight " << meta.weight << ", current block weight " << total_weight << "/" << max_total_weight << ", current coinbase " << print_money(best_coinbase));
  
        // Can not exceed maximum block weight
        if (max_total_weight < total_weight + meta.weight)
        {
          LOG_PRINT_L2("  would exceed maximum block weight");
          continue;
        }
  
        // start using the optimal filling algorithm from v5
        if (version >= 5)
        {
          // If we're getting lower coinbase tx,
          // stop including more tx
          uint64_t block_reward;
          if(!get_block_reward(median_weight, total_weight + meta.weight, already_generated_coins, block_reward, version))
          {
            LOG_PRINT_L2("  would exceed maximum block weight");
            continue;
          }
          coinbase = block_reward + fee + meta.fee;
          if (coinbase < template_accept_threshold(best_coinbase))
          {
            LOG_PRINT_L2("  would decrease coinbase to " << print_money(coinbase));
            continue;
          }
        }
        else
        {
          // If we've exceeded the penalty free weight,
          // stop including more tx
          if (total_weight > median_weight)
          {
            LOG_PRINT_L2("  would exceed median block weight");
            break;
          }
        }
  
        cryptonote::blobdata txblob = m_blockchain.get_txpool_tx_blob(sorted_it->second);
        cryptonote::transaction tx;
  
        // Skip transactions that are not ready to be
        // included into the blockchain or that are
        // missing key images
        const cryptonote::txpool_tx_meta_t original_meta = meta;
        bool ready = false;
        try
        {
          ready = is_transaction_ready_to_go(meta, sorted_it->second, txblob, tx);
        }
        catch (const std::exception &e)
        {
          MERROR("Failed to check transaction readiness: " << e.what());
          // continue, not fatal
        }
        if (memcmp(&original_meta, &meta, sizeof(meta)))
        {
          try
  	{
  	  m_blockchain.update_txpool_tx(sorted_it->second, meta);
  	}
          catch (const std::exception &e)
  	{
  	  MERROR("Failed to update tx meta: " << e.what());
  	  // continue, not fatal
  	}
        }
        if (!ready)
        {
          LOG_PRINT_L2("  not ready to go");
          continue;
        }
        if (have_key_images(k_images, tx))
        {
          LOG_PRINT_L2("  key images already seen");
          continue;
        }
  
        bl.tx_hashes.push_back(sorted_it->second);
        total_weight += meta.weight;
        fee += meta.fee;
        best_coinbase = coinbase;
        append_key_images(k_images, tx);
        LOG_PRINT_L2("  added, new block weight " << total_weight << "/" << max_total_weight << ", coinbase " << print_money(best_coinbase));
      }
  
      expected_reward = best_coinbase;
      LOG_PRINT_L2("Block template filled with " << bl.tx_hashes.size() << " txes, weight "
          << total_weight << "/" << max_total_weight << ", coinbase " << print_money(best_coinbase)
          << " (including " << print_money(fee) << " in fees)");
      return true;
    }
    //---------------------------------------------------------------------------------
    size_t tx_memory_pool::validate(uint8_t version)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
      size_t tx_weight_limit = get_transaction_weight_limit(version);
      std::unordered_set<crypto::hash> remove;
  
      m_txpool_weight = 0;
      m_blockchain.for_all_txpool_txes([this, &remove, tx_weight_limit](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata*) {
        m_txpool_weight += meta.weight;
        if (meta.weight > tx_weight_limit) {
          LOG_PRINT_L1("Transaction " << txid << " is too big (" << meta.weight << " bytes), removing it from pool");
          remove.insert(txid);
        }
        else if (m_blockchain.have_tx(txid)) {
          LOG_PRINT_L1("Transaction " << txid << " is in the blockchain, removing it from pool");
          remove.insert(txid);
        }
        return true;
      }, false);
  
      size_t n_removed = 0;
      if (!remove.empty())
      {
        LockedTXN lock(m_blockchain);
        for (const crypto::hash &txid: remove)
        {
          try
          {
            cryptonote::blobdata txblob = m_blockchain.get_txpool_tx_blob(txid);
            cryptonote::transaction tx;
            if (!parse_and_validate_tx_from_blob(txblob, tx))
            {
              MERROR("Failed to parse tx from txpool");
              continue;
            }
            // remove tx from db first
            m_blockchain.remove_txpool_tx(txid);
            m_txpool_weight -= get_transaction_weight(tx, txblob.size());
            remove_transaction_keyimages(tx);
            auto sorted_it = find_tx_in_sorted_container(txid);
            if (sorted_it == m_txs_by_fee_and_receive_time.end())
            {
              LOG_PRINT_L1("Removing tx " << txid << " from tx pool, but it was not found in the sorted txs container!");
            }
            else
            {
              m_txs_by_fee_and_receive_time.erase(sorted_it);
            }
            ++n_removed;
          }
          catch (const std::exception &e)
          {
            MERROR("Failed to remove invalid tx from pool");
            // continue
          }
        }
      }
      if (n_removed > 0)
        ++m_cookie;
      return n_removed;
    }
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::init(size_t max_txpool_weight)
    {
      CRITICAL_REGION_LOCAL(m_transactions_lock);
      CRITICAL_REGION_LOCAL1(m_blockchain);
  
      m_txpool_max_weight = max_txpool_weight ? max_txpool_weight : DEFAULT_TXPOOL_MAX_WEIGHT;
      m_txs_by_fee_and_receive_time.clear();
      m_spent_key_images.clear();
      m_txpool_weight = 0;
      std::vector<crypto::hash> remove;
  
      // first add the not kept by block, then the kept by block,
      // to avoid rejection due to key image collision
      for (int pass = 0; pass < 2; ++pass)
      {
        const bool kept = pass == 1;
        bool r = m_blockchain.for_all_txpool_txes([this, &remove, kept](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata *bd) {
          if (!!kept != !!meta.kept_by_block)
            return true;
          cryptonote::transaction tx;
          if (!parse_and_validate_tx_from_blob(*bd, tx))
          {
            MWARNING("Failed to parse tx from txpool, removing");
            remove.push_back(txid);
            return true;
          }
          if (!insert_key_images(tx, meta.kept_by_block))
          {
            MFATAL("Failed to insert key images from txpool tx");
            return false;
          }
          m_txs_by_fee_and_receive_time.emplace(std::pair<double, time_t>(meta.fee / (double)meta.weight, meta.receive_time), txid);
          m_txpool_weight += meta.weight;
          return true;
        }, true);
        if (!r)
          return false;
      }
      if (!remove.empty())
      {
        LockedTXN lock(m_blockchain);
        for (const auto &txid: remove)
        {
          try
          {
            m_blockchain.remove_txpool_tx(txid);
          }
          catch (const std::exception &e)
          {
            MWARNING("Failed to remove corrupt transaction: " << txid);
            // ignore error
          }
        }
      }
  
      m_cookie = 0;
  
      // Ignore deserialization error
      return true;
    }
  
    //---------------------------------------------------------------------------------
    bool tx_memory_pool::deinit()
    {
      return true;
    }
  }
  