text: // Copyright (c) 2014-2019, The Monero Project
  //
  // All rights reserved.
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  // 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
  
  #pragma once
  #include "include_base_utils.h"
  
  #include <set>
  #include <tuple>
  #include <unordered_map>
  #include <unordered_set>
  #include <queue>
  #include <boost/serialization/version.hpp>
  #include <boost/utility.hpp>
  
  #include "span.h"
  #include "string_tools.h"
  #include "syncobj.h"
  #include "math_helper.h"
  #include "cryptonote_basic/cryptonote_basic_impl.h"
  #include "cryptonote_basic/verification_context.h"
  #include "cryptonote_protocol/enums.h"
  #include "blockchain_db/blockchain_db.h"
  #include "crypto/hash.h"
  #include "rpc/core_rpc_server_commands_defs.h"
  #include "rpc/message_data_structs.h"
  
  namespace cryptonote
  {
    class Blockchain;
    /************************************************************************/
    /*                                                                      */
    /************************************************************************/
  
    //! tuple of <deregister, transaction fee, receive time> for organization
    typedef std::pair<std::tuple<bool, double, std::time_t>, crypto::hash> tx_by_fee_and_receive_time_entry;
  
    class txCompare
    {
    public:
      bool operator()(const tx_by_fee_and_receive_time_entry& a, const tx_by_fee_and_receive_time_entry& b) const
      {
  		std::string ahash(a.second.data, sizeof(a.second.data));
  		std::string bhash(b.second.data, sizeof(b.second.data));
  		//      prioritize      deregister             fee                   arrival time      hash
  		return std::make_tuple(!std::get<0>(a.first), -std::get<1>(a.first), std::get<2>(a.first), ahash)
  			< std::make_tuple(!std::get<0>(b.first), -std::get<1>(b.first), std::get<2>(b.first), bhash);
      }
    };
  
    //! container for sorting transactions by fee per unit size
    typedef std::set<tx_by_fee_and_receive_time_entry, txCompare> sorted_tx_container;
  
    /**
     * @brief Transaction pool, handles transactions which are not part of a block
     *
     * This class handles all transactions which have been received, but not as
     * part of a block.
     *
     * This handling includes:
     *   storing the transactions
     *   organizing the transactions by fee per weight unit
     *   taking/giving transactions to and from various other components
     *   saving the transactions to disk on shutdown
     *   helping create a new block template by choosing transactions for it
     *
     */
    class tx_memory_pool: boost::noncopyable
    {
    public:
      /**
       * @brief Constructor
       *
       * @param bchs a Blockchain class instance, for getting chain info
       */
      tx_memory_pool(Blockchain& bchs);
  
  
      /**
       * @copydoc add_tx(transaction&, tx_verification_context&, bool, bool, uint8_t)
       *
       * @param id the transaction's hash
       * @tx_relay how the transaction was received
       * @param tx_weight the transaction's weight
       */
      bool add_tx(transaction &tx, const crypto::hash &id, const cryptonote::blobdata &blob, size_t tx_weight, tx_verification_context& tvc, relay_method tx_relay, bool relayed, uint8_t version);
  
      /**
       * @brief add a transaction to the transaction pool
       *
       * Most likely the transaction will come from the network, but it is
       * also possible for transactions to come from popped blocks during
       * a reorg, or from local clients creating a transaction and
       * submitting it to the network
       *
       * @param tx the transaction to be added
       * @param tvc return-by-reference status about the transaction verification
       * @tx_relay how the transaction was received
       * @param relayed was this transaction from the network or a local client?
       * @param version the version used to create the transaction
       *
       * @return true if the transaction passes validations, otherwise false
       */
      bool add_tx(transaction &tx, tx_verification_context& tvc, relay_method tx_relay, bool relayed, uint8_t version);
  
      /**
       * @brief takes a transaction with the given hash from the pool
       *
       * @param id the hash of the transaction
       * @param tx return-by-reference the transaction taken
       * @param txblob return-by-reference the transaction as a blob
       * @param tx_weight return-by-reference the transaction's weight
       * @param fee the transaction fee
       * @param relayed return-by-reference was transaction relayed to us by the network?
       * @param do_not_relay return-by-reference is transaction not to be relayed to the network?
       * @param double_spend_seen return-by-reference was a double spend seen for that transaction?
       * @param pruned return-by-reference is the tx pruned
       *
       * @return true unless the transaction cannot be found in the pool
       */
      bool take_tx(const crypto::hash &id, transaction &tx, cryptonote::blobdata &txblob, size_t& tx_weight, uint64_t& fee, bool &relayed, bool &do_not_relay, bool &double_spend_seen, bool &pruned);
  
      /**
       * @brief checks if the pool has a transaction with the given hash
       *
       * @param id the hash to look for
       * @param tx_category a filter for txes
       *
       * @return true if the transaction is in the pool and meets tx_category requirements
       */
      bool have_tx(const crypto::hash &id, relay_category tx_category) const;
  
      /**
       * @brief action to take when notified of a block added to the blockchain
       *
       * Currently does nothing
       *
       * @param new_block_height the height of the blockchain after the change
       * @param top_block_id the hash of the new top block
       *
       * @return true
       */
      bool on_blockchain_inc(uint64_t new_block_height, const crypto::hash& top_block_id);
  
      /**
       * @brief action to take when notified of a block removed from the blockchain
       *
       * Currently does nothing
       *
       * @param new_block_height the height of the blockchain after the change
       * @param top_block_id the hash of the new top block
       *
       * @return true
       */
      bool on_blockchain_dec(uint64_t new_block_height, const crypto::hash& top_block_id);
  
      /**
       * @brief action to take periodically
       *
       * Currently checks transaction pool for stale ("stuck") transactions
       */
      void on_idle();
  
      /**
       * @brief locks the transaction pool
       */
      void lock() const;
  
      /**
       * @brief unlocks the transaction pool
       */
      void unlock() const;
  
      // load/store operations
  
      /**
       * @brief loads pool state (if any) from disk, and initializes pool
       *
       * @param max_txpool_weight the max weight in bytes
       * @param mine_stem_txes whether to mine txes in stem relay mode
       *
       * @return true
       */
      bool init(size_t max_txpool_weight = 0, bool mine_stem_txes = false);
  
      /**
       * @brief attempts to save the transaction pool state to disk
       *
       * Currently fails (returns false) if the data directory from init()
       * does not exist and cannot be created, but returns true even if
       * saving to disk is unsuccessful.
       *
       * @return true in most cases (see above)
       */
      bool deinit();
  
      /**
       * @brief Chooses transactions for a block to include
       *
       * @param bl return-by-reference the block to fill in with transactions
       * @param median_weight the current median block weight
       * @param already_generated_coins the current total number of coins "minted"
       * @param total_weight return-by-reference the total weight of the new block
       * @param fee return-by-reference the total of fees from the included transactions
       * @param expected_reward return-by-reference the total reward awarded to the miner finding this block, including transaction fees
       * @param version hard fork version to use for consensus rules
       *
       * @return true
       */
      bool 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);
  
      /**
       * @brief get a list of all transactions in the pool
       *
       * @param txs return-by-reference the list of transactions
       * @param include_sensitive return stempool, anonymity-pool, and unrelayed txes
       *
       */
      void get_transactions(std::vector<transaction>& txs, bool include_sensitive = false) const;
  
      /**
       * @brief get a list of all transaction hashes in the pool
       *
       * @param txs return-by-reference the list of transactions
       * @param include_sensitive return stempool, anonymity-pool, and unrelayed txes
       *
       */
      void get_transaction_hashes(std::vector<crypto::hash>& txs, bool include_sensitive = false) const;
  
      /**
       * @brief get (weight, fee, receive time) for all transaction in the pool
       *
       * @param txs return-by-reference that data
       * @param include_sensitive return stempool, anonymity-pool, and unrelayed txes
       *
       */
      void get_transaction_backlog(std::vector<tx_backlog_entry>& backlog, bool include_sensitive = false) const;
  
      /**
       * @brief get a summary statistics of all transaction hashes in the pool
       *
       * @param stats return-by-reference the pool statistics
       * @param include_sensitive return stempool, anonymity-pool, and unrelayed txes
       *
       */
      void get_transaction_stats(struct txpool_stats& stats, bool include_sensitive = false) const;
  
      /**
       * @brief get information about all transactions and key images in the pool
       *
       * see documentation on tx_info and spent_key_image_info for more details
       *
       * @param tx_infos return-by-reference the transactions' information
       * @param key_image_infos return-by-reference the spent key images' information
       * @param include_sensitive_data return stempool, anonymity-pool, and unrelayed
       *    txes and fields that are sensitive to the node privacy
       *
       * @return true
       */
      bool 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 = false) const;
  
      /**
       * @brief get information about all transactions and key images in the pool
       *
       * see documentation on tx_in_pool and key_images_with_tx_hashes for more details
       *
       * @param tx_infos [out] the transactions' information
       * @param key_image_infos [out] the spent key images' information
       *
       * @return true
       */
      bool get_pool_for_rpc(std::vector<cryptonote::rpc::tx_in_pool>& tx_infos, cryptonote::rpc::key_images_with_tx_hashes& key_image_infos) const;
  
      /**
       * @brief check for presence of key images in the pool
       *
       * @param key_images [in] vector of key images to check
       * @param spent [out] vector of bool to return
       *
       * @return true
       */
      bool check_for_key_images(const std::vector<crypto::key_image>& key_images, std::vector<bool>& spent) const;
  
      /**
       * @brief get a specific transaction from the pool
       *
       * @param h the hash of the transaction to get
       * @param tx return-by-reference the transaction blob requested
       * @param tx_relay last relay method us
       *
       * @return true if the transaction is found, otherwise false
       */
      bool get_transaction(const crypto::hash& h, cryptonote::blobdata& txblob, relay_category tx_category) const;
  
      /**
       * @brief get a list of all relayable transactions and their hashes
       *
       * "relayable" in this case means:
       *   nonzero fee
       *   hasn't been relayed too recently
       *   isn't old enough that relaying it is considered harmful
       * Note a transaction can be "relayable" even if do_not_relay is true
       *
       * @param txs return-by-reference the transactions and their hashes
       *
       * @return true
       */
      bool get_relayable_transactions(std::vector<std::tuple<crypto::hash, cryptonote::blobdata, relay_method>>& txs) const;
  
      /**
       * @brief tell the pool that certain transactions were just relayed
       *
       * @param hashes list of tx hashes that are about to be relayed
       * @param tx_relay update how the tx left this node
       */
      void set_relayed(epee::span<const crypto::hash> hashes, relay_method tx_relay);
  
      /**
       * @brief get the total number of transactions in the pool
       *
       * @return the number of transactions in the pool
       */
      size_t get_transactions_count(bool include_sensitive = false) const;
  
      /**
       * @brief get a string containing human-readable pool information
       *
       * @param short_format whether to use a shortened format for the info
       *
       * @return the string
       */
      std::string print_pool(bool short_format) const;
  
      /**
       * @brief remove transactions from the pool which are no longer valid
       *
       * With new versions of the currency, what conditions render a transaction
       * invalid may change.  This function clears those which were received
       * before a version change and no longer conform to requirements.
       *
       * @param version the version the transactions must conform to
       *
       * @return the number of transactions removed
       */
      size_t validate(uint8_t version);
  
       /**
        * @brief return the cookie
        *
        * @return the cookie
        */
      uint64_t cookie() const { return m_cookie; }
  
      /**
       * @brief get the cumulative txpool weight in bytes
       *
       * @return the cumulative txpool weight in bytes
       */
      size_t get_txpool_weight() const;
  
      /**
       * @brief set the max cumulative txpool weight in bytes
       *
       * @param bytes the max cumulative txpool weight in bytes
       */
      void set_txpool_max_weight(size_t bytes);
  
  #define CURRENT_MEMPOOL_ARCHIVE_VER    11
  #define CURRENT_MEMPOOL_TX_DETAILS_ARCHIVE_VER    13
  
      /**
       * @brief information about a single transaction
       */
      struct tx_details
      {
        transaction tx;  //!< the transaction
        size_t blob_size;  //!< the transaction's size
        size_t weight;  //!< the transaction's weight
        uint64_t fee;  //!< the transaction's fee amount
        crypto::hash max_used_block_id;  //!< the hash of the highest block referenced by an input
        uint64_t max_used_block_height;  //!< the height of the highest block referenced by an input
  
        //! whether or not the transaction has been in a block before
        /*! if the transaction was returned to the pool from the blockchain
         *  due to a reorg, then this will be true
         */
        bool kept_by_block;
  
        //! the highest block the transaction referenced when last checking it failed
        /*! if verifying a transaction's inputs fails, it's possible this is due
         *  to a reorg since it was created (if it used recently created outputs
         *  as inputs).
         */
        uint64_t last_failed_height;
  
        //! the hash of the highest block the transaction referenced when last checking it failed
        /*! if verifying a transaction's inputs fails, it's possible this is due
         *  to a reorg since it was created (if it used recently created outputs
         *  as inputs).
         */
        crypto::hash last_failed_id;
  
        time_t receive_time;  //!< the time when the transaction entered the pool
  
        time_t last_relayed_time;  //!< the last time the transaction was relayed to the network
        bool relayed;  //!< whether or not the transaction has been relayed to the network
        bool do_not_relay; //!< to avoid relay this transaction to the network
  
        bool double_spend_seen; //!< true iff another tx was seen double spending this one
      };
  
      /**
       * @brief get infornation about a single transaction
       */
      bool get_transaction_info(const crypto::hash &txid, tx_details &td) const;
  
      /**
       * @brief get transactions not in the passed set
       */
      bool get_complement(const std::vector<crypto::hash> &hashes, std::vector<cryptonote::blobdata> &txes) const;
  
    private:
  
      /**
       * @brief insert key images into m_spent_key_images
       *
       * @return true on success, false on error
       */
      bool insert_key_images(const transaction_prefix &tx, const crypto::hash &txid, relay_method tx_relay);
  
      /**
       * @brief remove old transactions from the pool
       *
       * After a certain time, it is assumed that a transaction which has not
       * yet been mined will likely not be mined.  These transactions are removed
       * from the pool to avoid buildup.
       *
       * @return true
       */
      bool remove_stuck_transactions();
  
      /**
       * @brief check if a transaction in the pool has a given spent key image
       *
       * @param key_im the spent key image to look for
       * @param txid hash of the new transaction where `key_im` was seen.
       *
       * @return true if the spent key image is present, otherwise false
       */
      /**
     * @brief check if the deregistration tx already exists in the pool.
     * @return true if it already exists
     *
     */
     bool have_deregister_tx_already(transaction const &tx) const;
      bool have_tx_keyimg_as_spent(const crypto::key_image& key_im, const crypto::hash& txid) const;
  
      /**
       * @brief check if any spent key image in a transaction is in the pool
       *
       * Checks if any of the spent key images in a given transaction are present
       * in any of the transactions in the transaction pool.
       *
       * @note see tx_pool::have_tx_keyimg_as_spent
       *
       * @param tx the transaction to check spent key images of
       * @param txid hash of `tx`.
       *
       * @return true if any spent key images are present in the pool, otherwise false
       */
      bool have_tx_keyimges_as_spent(const transaction& tx, const crypto::hash& txid) const;
  
      /**
       * @brief forget a transaction's spent key images
       *
       * Spent key images are stored separately from transactions for
       * convenience/speed, so this is part of the process of removing
       * a transaction from the pool.
       *
       * @param tx the transaction
       * @param txid the transaction's hash
       *
       * @return false if any key images to be removed cannot be found, otherwise true
       */
      bool remove_transaction_keyimages(const transaction_prefix& tx, const crypto::hash &actual_hash);
  
      /**
       * @brief check if any of a transaction's spent key images are present in a given set
       *
       * @param kic the set of key images to check against
       * @param tx the transaction to check
       *
       * @return true if any key images present in the set, otherwise false
       */
      static bool have_key_images(const std::unordered_set<crypto::key_image>& kic, const transaction_prefix& tx);
  
      /**
       * @brief append the key images from a transaction to the given set
       *
       * @param kic the set of key images to append to
       * @param tx the transaction
       *
       * @return false if any append fails, otherwise true
       */
      static bool append_key_images(std::unordered_set<crypto::key_image>& kic, const transaction_prefix& tx);
  
      /**
       * @brief check if a transaction is a valid candidate for inclusion in a block
       *
       * @param txd the transaction to check (and info about it)
       * @param txid the txid of the transaction to check
       * @param txblob the transaction blob to check
       * @param tx the parsed transaction, if successful
       *
       * @return true if the transaction is good to go, otherwise false
       */
      bool is_transaction_ready_to_go(txpool_tx_meta_t& txd, const crypto::hash &txid, const cryptonote::blobdata &txblob, transaction&tx) const;
  
      /**
       * @brief mark all transactions double spending the one passed
       */
      void mark_double_spend(const transaction &tx);
  
      /**
       * @brief prune lowest fee/byte txes till we're not above bytes
       *
       * if bytes is 0, use m_txpool_max_weight
       */
      void prune(size_t bytes = 0);
  
      //TODO: confirm the below comments and investigate whether or not this
      //      is the desired behavior
      //! map key images to transactions which spent them
      /*! this seems odd, but it seems that multiple transactions can exist
       *  in the pool which both have the same spent key.  This would happen
       *  in the event of a reorg where someone creates a new/different
       *  transaction on the assumption that the original will not be in a
       *  block again.
       */
      typedef std::unordered_map<crypto::key_image, std::unordered_set<crypto::hash>> key_images_container;
  
  #if defined(DEBUG_CREATE_BLOCK_TEMPLATE)
  public:
  #endif
      mutable epee::critical_section m_transactions_lock;  //!< lock for the pool
  #if defined(DEBUG_CREATE_BLOCK_TEMPLATE)
  private:
  #endif
  
      //! container for spent key images from the transactions in the pool
      key_images_container m_spent_key_images;
  
      //TODO: this time should be a named constant somewhere, not hard-coded
      //! interval on which to check for stale/"stuck" transactions
      epee::math_helper::once_a_time_seconds<30> m_remove_stuck_tx_interval;
  
      //TODO: look into doing this better
      //!< container for transactions organized by fee per size and receive time
      sorted_tx_container m_txs_by_fee_and_receive_time;
  
      std::atomic<uint64_t> m_cookie; //!< incremented at each change
  
      /**
       * @brief get an iterator to a transaction in the sorted container
       *
       * @param id the hash of the transaction to look for
       *
       * @return an iterator, possibly to the end of the container if not found
       */
      sorted_tx_container::iterator find_tx_in_sorted_container(const crypto::hash& id) const;
  
      //! cache/call Blockchain::check_tx_inputs results
      bool 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 = false) const;
  
      //! transactions which are unlikely to be included in blocks
      /*! These transactions are kept in RAM in case they *are* included
       *  in a block eventually, but this container is not saved to disk.
       */
      std::unordered_set<crypto::hash> m_timed_out_transactions;
  
      Blockchain& m_blockchain;  //!< reference to the Blockchain object
  
      size_t m_txpool_max_weight;
      size_t m_txpool_weight;
      bool m_mine_stem_txes;
  
      mutable std::unordered_map<crypto::hash, std::tuple<bool, tx_verification_context, uint64_t, crypto::hash>> m_input_cache;
  
      std::unordered_map<crypto::hash, transaction> m_parsed_tx_cache;
    };
  }
  
  namespace boost
  {
    namespace serialization
    {
      template<class archive_t>
      void serialize(archive_t & ar, cryptonote::tx_memory_pool::tx_details& td, const unsigned int version)
      {
        ar & td.blob_size;
        ar & td.fee;
        ar & td.tx;
        ar & td.max_used_block_height;
        ar & td.max_used_block_id;
        ar & td.last_failed_height;
        ar & td.last_failed_id;
        ar & td.receive_time;
        ar & td.last_relayed_time;
        ar & td.relayed;
        if (version < 11)
          return;
        ar & td.kept_by_block;
        if (version < 12)
          return;
        ar & td.do_not_relay;
        if (version < 13)
          return;
        ar & td.weight;
      }
    }
  }
  BOOST_CLASS_VERSION(cryptonote::tx_memory_pool, CURRENT_MEMPOOL_ARCHIVE_VER)
  BOOST_CLASS_VERSION(cryptonote::tx_memory_pool::tx_details, CURRENT_MEMPOOL_TX_DETAILS_ARCHIVE_VER)
  