LCOV - code coverage report
Current view: top level - src/wallet - coinselection.h (source / functions) Coverage Total Hit
Test: fuzz_coverage.info Lines: 98.2 % 56 55
Test Date: 2024-11-04 04:15:01 Functions: 100.0 % 7 7
Branches: 47.1 % 104 49

             Branch data     Line data    Source code
       1                 :             : // Copyright (c) 2017-2022 The Bitcoin Core developers
       2                 :             : // Distributed under the MIT software license, see the accompanying
       3                 :             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4                 :             : 
       5                 :             : #ifndef BITCOIN_WALLET_COINSELECTION_H
       6                 :             : #define BITCOIN_WALLET_COINSELECTION_H
       7                 :             : 
       8                 :             : #include <consensus/amount.h>
       9                 :             : #include <consensus/consensus.h>
      10                 :             : #include <outputtype.h>
      11                 :             : #include <policy/feerate.h>
      12                 :             : #include <primitives/transaction.h>
      13                 :             : #include <random.h>
      14                 :             : #include <util/check.h>
      15                 :             : #include <util/insert.h>
      16                 :             : #include <util/result.h>
      17                 :             : 
      18                 :             : #include <optional>
      19                 :             : 
      20                 :             : 
      21                 :             : namespace wallet {
      22                 :             : //! lower bound for randomly-chosen target change amount
      23                 :             : static constexpr CAmount CHANGE_LOWER{50000};
      24                 :             : //! upper bound for randomly-chosen target change amount
      25                 :             : static constexpr CAmount CHANGE_UPPER{1000000};
      26                 :             : 
      27                 :             : /** A UTXO under consideration for use in funding a new transaction. */
      28         [ +  - ]:    30820151 : struct COutput {
      29                 :             : private:
      30                 :             :     /** The output's value minus fees required to spend it and bump its unconfirmed ancestors to the target feerate. */
      31                 :             :     std::optional<CAmount> effective_value;
      32                 :             : 
      33                 :             :     /** The fee required to spend this output at the transaction's target feerate and to bump its unconfirmed ancestors to the target feerate. */
      34                 :             :     std::optional<CAmount> fee;
      35                 :             : 
      36                 :             : public:
      37                 :             :     /** The outpoint identifying this UTXO */
      38                 :             :     COutPoint outpoint;
      39                 :             : 
      40                 :             :     /** The output itself */
      41                 :             :     CTxOut txout;
      42                 :             : 
      43                 :             :     /**
      44                 :             :      * Depth in block chain.
      45                 :             :      * If > 0: the tx is on chain and has this many confirmations.
      46                 :             :      * If = 0: the tx is waiting confirmation.
      47                 :             :      * If < 0: a conflicting tx is on chain and has this many confirmations. */
      48                 :             :     int depth;
      49                 :             : 
      50                 :             :     /** Pre-computed estimated size of this output as a fully-signed input in a transaction. Can be -1 if it could not be calculated */
      51                 :             :     int input_bytes;
      52                 :             : 
      53                 :             :     /** Whether we have the private keys to spend this output */
      54                 :             :     bool spendable;
      55                 :             : 
      56                 :             :     /** Whether we know how to spend this output, ignoring the lack of keys */
      57                 :             :     bool solvable;
      58                 :             : 
      59                 :             :     /**
      60                 :             :      * Whether this output is considered safe to spend. Unconfirmed transactions
      61                 :             :      * from outside keys and unconfirmed replacement transactions are considered
      62                 :             :      * unsafe and will not be used to fund new spending transactions.
      63                 :             :      */
      64                 :             :     bool safe;
      65                 :             : 
      66                 :             :     /** The time of the transaction containing this output as determined by CWalletTx::nTimeSmart */
      67                 :             :     int64_t time;
      68                 :             : 
      69                 :             :     /** Whether the transaction containing this output is sent from the owning wallet */
      70                 :             :     bool from_me;
      71                 :             : 
      72                 :             :     /** The fee required to spend this output at the consolidation feerate. */
      73                 :             :     CAmount long_term_fee{0};
      74                 :             : 
      75                 :             :     /** The fee necessary to bump this UTXO's ancestor transactions to the target feerate */
      76                 :             :     CAmount ancestor_bump_fees{0};
      77                 :             : 
      78                 :     7562546 :     COutput(const COutPoint& outpoint, const CTxOut& txout, int depth, int input_bytes, bool spendable, bool solvable, bool safe, int64_t time, bool from_me, const std::optional<CFeeRate> feerate = std::nullopt)
      79                 :     7562546 :         : outpoint{outpoint},
      80                 :     7562546 :           txout{txout},
      81                 :     7562546 :           depth{depth},
      82                 :     7562546 :           input_bytes{input_bytes},
      83                 :     7562546 :           spendable{spendable},
      84                 :     7562546 :           solvable{solvable},
      85                 :     7562546 :           safe{safe},
      86                 :     7562546 :           time{time},
      87                 :     7562546 :           from_me{from_me}
      88                 :             :     {
      89         [ +  - ]:     7562546 :         if (feerate) {
      90                 :             :             // base fee without considering potential unconfirmed ancestors
      91   [ +  -  +  -  :     7562546 :             fee = input_bytes < 0 ? 0 : feerate.value().GetFee(input_bytes);
                   +  - ]
      92         [ +  - ]:     7562546 :             effective_value = txout.nValue - fee.value();
      93                 :             :         }
      94                 :     7562546 :     }
      95                 :             : 
      96                 :             :     COutput(const COutPoint& outpoint, const CTxOut& txout, int depth, int input_bytes, bool spendable, bool solvable, bool safe, int64_t time, bool from_me, const CAmount fees)
      97                 :             :         : COutput(outpoint, txout, depth, input_bytes, spendable, solvable, safe, time, from_me)
      98                 :             :     {
      99                 :             :         // if input_bytes is unknown, then fees should be 0, if input_bytes is known, then the fees should be a positive integer or 0 (input_bytes known and fees = 0 only happens in the tests)
     100                 :             :         assert((input_bytes < 0 && fees == 0) || (input_bytes > 0 && fees >= 0));
     101                 :             :         fee = fees;
     102                 :             :         effective_value = txout.nValue - fee.value();
     103                 :             :     }
     104                 :             : 
     105                 :             :     std::string ToString() const;
     106                 :             : 
     107                 :             :     bool operator<(const COutput& rhs) const
     108                 :             :     {
     109                 :             :         return outpoint < rhs.outpoint;
     110                 :             :     }
     111                 :             : 
     112                 :     7111532 :     void ApplyBumpFee(CAmount bump_fee)
     113                 :             :     {
     114         [ -  + ]:     7111532 :         assert(bump_fee >= 0);
     115                 :     7111532 :         ancestor_bump_fees = bump_fee;
     116         [ -  + ]:     7111532 :         assert(fee);
     117                 :     7111532 :         *fee += bump_fee;
     118                 :             :         // Note: assert(effective_value - bump_fee == nValue - fee.value());
     119                 :     7111532 :         effective_value = txout.nValue - fee.value();
     120                 :     7111532 :     }
     121                 :             : 
     122                 :     6468327 :     CAmount GetFee() const
     123                 :             :     {
     124         [ -  + ]:     6468327 :         assert(fee.has_value());
     125                 :     6468327 :         return fee.value();
     126                 :             :     }
     127                 :             : 
     128                 :    15899380 :     CAmount GetEffectiveValue() const
     129                 :             :     {
     130         [ -  + ]:    15899380 :         assert(effective_value.has_value());
     131                 :    15899380 :         return effective_value.value();
     132                 :             :     }
     133                 :             : 
     134   [ +  -  -  - ]:     6870548 :     bool HasEffectiveValue() const { return effective_value.has_value(); }
     135                 :             : };
     136                 :             : 
     137                 :             : /** Parameters for one iteration of Coin Selection. */
     138                 :             : struct CoinSelectionParams {
     139                 :             :     /** Randomness to use in the context of coin selection. */
     140                 :             :     FastRandomContext& rng_fast;
     141                 :             :     /** Size of a change output in bytes, determined by the output type. */
     142                 :             :     int change_output_size = 0;
     143                 :             :     /** Size of the input to spend a change output in virtual bytes. */
     144                 :             :     int change_spend_size = 0;
     145                 :             :     /** Mininmum change to target in Knapsack solver and CoinGrinder:
     146                 :             :      * select coins to cover the payment and at least this value of change. */
     147                 :             :     CAmount m_min_change_target{0};
     148                 :             :     /** Minimum amount for creating a change output.
     149                 :             :      * If change budget is smaller than min_change then we forgo creation of change output.
     150                 :             :      */
     151                 :             :     CAmount min_viable_change{0};
     152                 :             :     /** Cost of creating the change output. */
     153                 :             :     CAmount m_change_fee{0};
     154                 :             :     /** Cost of creating the change output + cost of spending the change output in the future. */
     155                 :             :     CAmount m_cost_of_change{0};
     156                 :             :     /** The targeted feerate of the transaction being built. */
     157                 :             :     CFeeRate m_effective_feerate;
     158                 :             :     /** The feerate estimate used to estimate an upper bound on what should be sufficient to spend
     159                 :             :      * the change output sometime in the future. */
     160                 :             :     CFeeRate m_long_term_feerate;
     161                 :             :     /** If the cost to spend a change output at the discard feerate exceeds its value, drop it to fees. */
     162                 :             :     CFeeRate m_discard_feerate;
     163                 :             :     /** Size of the transaction before coin selection, consisting of the header and recipient
     164                 :             :      * output(s), excluding the inputs and change output(s). */
     165                 :             :     int tx_noinputs_size = 0;
     166                 :             :     /** Indicate that we are subtracting the fee from outputs */
     167                 :             :     bool m_subtract_fee_outputs = false;
     168                 :             :     /** When true, always spend all (up to OUTPUT_GROUP_MAX_ENTRIES) or none of the outputs
     169                 :             :      * associated with the same address. This helps reduce privacy leaks resulting from address
     170                 :             :      * reuse. Dust outputs are not eligible to be added to output groups and thus not considered. */
     171                 :             :     bool m_avoid_partial_spends = false;
     172                 :             :     /**
     173                 :             :      * When true, allow unsafe coins to be selected during Coin Selection. This may spend unconfirmed outputs:
     174                 :             :      * 1) Received from other wallets, 2) replacing other txs, 3) that have been replaced.
     175                 :             :      */
     176                 :             :     bool m_include_unsafe_inputs = false;
     177                 :             :     /** The maximum weight for this transaction. */
     178                 :             :     std::optional<int> m_max_tx_weight{std::nullopt};
     179                 :             : 
     180                 :             :     CoinSelectionParams(FastRandomContext& rng_fast, int change_output_size, int change_spend_size,
     181                 :             :                         CAmount min_change_target, CFeeRate effective_feerate,
     182                 :             :                         CFeeRate long_term_feerate, CFeeRate discard_feerate, int tx_noinputs_size, bool avoid_partial,
     183                 :             :                         std::optional<int> max_tx_weight = std::nullopt)
     184                 :             :         : rng_fast{rng_fast},
     185                 :             :           change_output_size(change_output_size),
     186                 :             :           change_spend_size(change_spend_size),
     187                 :             :           m_min_change_target(min_change_target),
     188                 :             :           m_effective_feerate(effective_feerate),
     189                 :             :           m_long_term_feerate(long_term_feerate),
     190                 :             :           m_discard_feerate(discard_feerate),
     191                 :             :           tx_noinputs_size(tx_noinputs_size),
     192                 :             :           m_avoid_partial_spends(avoid_partial),
     193                 :             :           m_max_tx_weight(max_tx_weight)
     194                 :             :     {
     195                 :             :     }
     196                 :      150175 :     CoinSelectionParams(FastRandomContext& rng_fast)
     197         [ -  + ]:      150175 :         : rng_fast{rng_fast} {}
     198                 :             : };
     199                 :             : 
     200                 :             : /** Parameters for filtering which OutputGroups we may use in coin selection.
     201                 :             :  * We start by being very selective and requiring multiple confirmations and
     202                 :             :  * then get more permissive if we cannot fund the transaction. */
     203                 :             : struct CoinEligibilityFilter
     204                 :             : {
     205                 :             :     /** Minimum number of confirmations for outputs that we sent to ourselves.
     206                 :             :      * We may use unconfirmed UTXOs sent from ourselves, e.g. change outputs. */
     207                 :             :     const int conf_mine;
     208                 :             :     /** Minimum number of confirmations for outputs received from a different wallet. */
     209                 :             :     const int conf_theirs;
     210                 :             :     /** Maximum number of unconfirmed ancestors aggregated across all UTXOs in an OutputGroup. */
     211                 :             :     const uint64_t max_ancestors;
     212                 :             :     /** Maximum number of descendants that a single UTXO in the OutputGroup may have. */
     213                 :             :     const uint64_t max_descendants;
     214                 :             :     /** When avoid_reuse=true and there are full groups (OUTPUT_GROUP_MAX_ENTRIES), whether or not to use any partial groups.*/
     215                 :             :     const bool m_include_partial_groups{false};
     216                 :             : 
     217                 :             :     CoinEligibilityFilter() = delete;
     218         [ +  - ]:      261476 :     CoinEligibilityFilter(int conf_mine, int conf_theirs, uint64_t max_ancestors) : conf_mine(conf_mine), conf_theirs(conf_theirs), max_ancestors(max_ancestors), max_descendants(max_ancestors) {}
     219   [ +  -  +  - ]:       63848 :     CoinEligibilityFilter(int conf_mine, int conf_theirs, uint64_t max_ancestors, uint64_t max_descendants) : conf_mine(conf_mine), conf_theirs(conf_theirs), max_ancestors(max_ancestors), max_descendants(max_descendants) {}
     220   [ +  -  +  -  :       69047 :     CoinEligibilityFilter(int conf_mine, int conf_theirs, uint64_t max_ancestors, uint64_t max_descendants, bool include_partial) : conf_mine(conf_mine), conf_theirs(conf_theirs), max_ancestors(max_ancestors), max_descendants(max_descendants), m_include_partial_groups(include_partial) {}
                   -  - ]
     221                 :             : 
     222                 :   115030263 :     bool operator<(const CoinEligibilityFilter& other) const {
     223                 :   115030263 :         return std::tie(conf_mine, conf_theirs, max_ancestors, max_descendants, m_include_partial_groups)
     224                 :   115030263 :                < std::tie(other.conf_mine, other.conf_theirs, other.max_ancestors, other.max_descendants, other.m_include_partial_groups);
     225                 :             :     }
     226                 :             : };
     227                 :             : 
     228                 :             : /** A group of UTXOs paid to the same output script. */
     229   [ +  +  +  + ]:   191245311 : struct OutputGroup
     230                 :             : {
     231                 :             :     /** The list of UTXOs contained in this output group. */
     232                 :             :     std::vector<std::shared_ptr<COutput>> m_outputs;
     233                 :             :     /** Whether the UTXOs were sent by the wallet to itself. This is relevant because we may want at
     234                 :             :      * least a certain number of confirmations on UTXOs received from outside wallets while trusting
     235                 :             :      * our own UTXOs more. */
     236                 :             :     bool m_from_me{true};
     237                 :             :     /** The total value of the UTXOs in sum. */
     238                 :             :     CAmount m_value{0};
     239                 :             :     /** The minimum number of confirmations the UTXOs in the group have. Unconfirmed is 0. */
     240                 :             :     int m_depth{999};
     241                 :             :     /** The aggregated count of unconfirmed ancestors of all UTXOs in this
     242                 :             :      * group. Not deduplicated and may overestimate when ancestors are shared. */
     243                 :             :     size_t m_ancestors{0};
     244                 :             :     /** The maximum count of descendants of a single UTXO in this output group. */
     245                 :             :     size_t m_descendants{0};
     246                 :             :     /** The value of the UTXOs after deducting the cost of spending them at the effective feerate. */
     247                 :             :     CAmount effective_value{0};
     248                 :             :     /** The fee to spend these UTXOs at the effective feerate. */
     249                 :             :     CAmount fee{0};
     250                 :             :     /** The fee to spend these UTXOs at the long term feerate. */
     251                 :             :     CAmount long_term_fee{0};
     252                 :             :     /** The feerate for spending a created change output eventually (i.e. not urgently, and thus at
     253                 :             :      * a lower feerate). Calculated using long term fee estimate. This is used to decide whether
     254                 :             :      * it could be economical to create a change output. */
     255                 :             :     CFeeRate m_long_term_feerate{0};
     256                 :             :     /** Indicate that we are subtracting the fee from outputs.
     257                 :             :      * When true, the value that is used for coin selection is the UTXO's real value rather than effective value */
     258                 :             :     bool m_subtract_fee_outputs{false};
     259                 :             :     /** Total weight of the UTXOs in this group. */
     260                 :             :     int m_weight{0};
     261                 :             : 
     262                 :             :     OutputGroup() = default;
     263                 :     5028299 :     OutputGroup(const CoinSelectionParams& params) :
     264         [ +  - ]:     5028299 :         m_long_term_feerate(params.m_long_term_feerate),
     265         [ +  - ]:     5028299 :         m_subtract_fee_outputs(params.m_subtract_fee_outputs)
     266                 :             :     {}
     267                 :             : 
     268                 :             :     void Insert(const std::shared_ptr<COutput>& output, size_t ancestors, size_t descendants);
     269                 :             :     bool EligibleForSpending(const CoinEligibilityFilter& eligibility_filter) const;
     270                 :             :     CAmount GetSelectionAmount() const;
     271                 :             : };
     272                 :             : 
     273                 :      776351 : struct Groups {
     274                 :             :     // Stores 'OutputGroup' containing only positive UTXOs (value > 0).
     275                 :             :     std::vector<OutputGroup> positive_group;
     276                 :             :     // Stores 'OutputGroup' which may contain both positive and negative UTXOs.
     277                 :             :     std::vector<OutputGroup> mixed_group;
     278                 :             : };
     279                 :             : 
     280                 :             : /** Stores several 'Groups' whose were mapped by output type. */
     281                 :      366273 : struct OutputGroupTypeMap
     282                 :             : {
     283                 :             :     // Maps output type to output groups.
     284                 :             :     std::map<OutputType, Groups> groups_by_type;
     285                 :             :     // All inserted groups, no type distinction.
     286                 :             :     Groups all_groups;
     287                 :             : 
     288                 :             :     // Based on the insert flag; appends group to the 'mixed_group' and, if value > 0, to the 'positive_group'.
     289                 :             :     // This affects both; the groups filtered by type and the overall groups container.
     290                 :             :     void Push(const OutputGroup& group, OutputType type, bool insert_positive, bool insert_mixed);
     291                 :             :     // Different output types count
     292         [ +  - ]:         853 :     size_t TypesCount() { return groups_by_type.size(); }
     293                 :             : };
     294                 :             : 
     295                 :             : typedef std::map<CoinEligibilityFilter, OutputGroupTypeMap> FilteredOutputGroups;
     296                 :             : 
     297                 :             : /** Choose a random change target for each transaction to make it harder to fingerprint the Core
     298                 :             :  * wallet based on the change output values of transactions it creates.
     299                 :             :  * Change target covers at least change fees and adds a random value on top of it.
     300                 :             :  * The random value is between 50ksat and min(2 * payment_value, 1milsat)
     301                 :             :  * When payment_value <= 25ksat, the value is just 50ksat.
     302                 :             :  *
     303                 :             :  * Making change amounts similar to the payment value may help disguise which output(s) are payments
     304                 :             :  * are which ones are change. Using double the payment value may increase the number of inputs
     305                 :             :  * needed (and thus be more expensive in fees), but breaks analysis techniques which assume the
     306                 :             :  * coins selected are just sufficient to cover the payment amount ("unnecessary input" heuristic).
     307                 :             :  *
     308                 :             :  * @param[in]   payment_value   Average payment value of the transaction output(s).
     309                 :             :  * @param[in]   change_fee      Fee for creating a change output.
     310                 :             :  */
     311                 :             : [[nodiscard]] CAmount GenerateChangeTarget(const CAmount payment_value, const CAmount change_fee, FastRandomContext& rng);
     312                 :             : 
     313                 :             : enum class SelectionAlgorithm : uint8_t
     314                 :             : {
     315                 :             :     BNB = 0,
     316                 :             :     KNAPSACK = 1,
     317                 :             :     SRD = 2,
     318                 :             :     CG = 3,
     319                 :             :     MANUAL = 4,
     320                 :             : };
     321                 :             : 
     322                 :             : std::string GetAlgorithmName(const SelectionAlgorithm algo);
     323                 :             : 
     324                 :     2913175 : struct SelectionResult
     325                 :             : {
     326                 :             : private:
     327                 :             :     /** Set of inputs selected by the algorithm to use in the transaction */
     328                 :             :     std::set<std::shared_ptr<COutput>> m_selected_inputs;
     329                 :             :     /** The target the algorithm selected for. Equal to the recipient amount plus non-input fees */
     330                 :             :     CAmount m_target;
     331                 :             :     /** The algorithm used to produce this result */
     332                 :             :     SelectionAlgorithm m_algo;
     333                 :             :     /** Whether the input values for calculations should be the effective value (true) or normal value (false) */
     334                 :             :     bool m_use_effective{false};
     335                 :             :     /** The computed waste */
     336                 :             :     std::optional<CAmount> m_waste;
     337                 :             :     /** False if algorithm was cut short by hitting limit of attempts and solution is non-optimal */
     338                 :             :     bool m_algo_completed{true};
     339                 :             :     /** The count of selections that were evaluated by this coin selection attempt */
     340                 :             :     size_t m_selections_evaluated;
     341                 :             :     /** Total weight of the selected inputs */
     342                 :             :     int m_weight{0};
     343                 :             :     /** How much individual inputs overestimated the bump fees for the shared ancestry */
     344                 :             :     CAmount bump_fee_group_discount{0};
     345                 :             : 
     346                 :             :     template<typename T>
     347                 :      830691 :     void InsertInputs(const T& inputs)
     348                 :             :     {
     349                 :             :         // Store sum of combined input sets to check that the results have no shared UTXOs
     350                 :      830691 :         const size_t expected_count = m_selected_inputs.size() + inputs.size();
     351                 :      830691 :         util::insert(m_selected_inputs, inputs);
     352         [ -  + ]:      830691 :         if (m_selected_inputs.size() != expected_count) {
     353   [ #  #  #  # ]:           0 :             throw std::runtime_error(STR_INTERNAL_BUG("Shared UTXOs among selection results"));
     354                 :             :         }
     355                 :      830691 :     }
     356                 :             : 
     357                 :             : public:
     358                 :      597792 :     explicit SelectionResult(const CAmount target, SelectionAlgorithm algo)
     359   [ +  -  +  - ]:      597792 :         : m_target(target), m_algo(algo) {}
           [ +  -  #  # ]
     360                 :             : 
     361                 :             :     SelectionResult() = delete;
     362                 :             : 
     363                 :             :     /** Get the sum of the input values */
     364                 :             :     [[nodiscard]] CAmount GetSelectedValue() const;
     365                 :             : 
     366                 :             :     [[nodiscard]] CAmount GetSelectedEffectiveValue() const;
     367                 :             : 
     368                 :             :     [[nodiscard]] CAmount GetTotalBumpFees() const;
     369                 :             : 
     370                 :             :     void Clear();
     371                 :             : 
     372                 :             :     void AddInput(const OutputGroup& group);
     373                 :             :     void AddInputs(const std::set<std::shared_ptr<COutput>>& inputs, bool subtract_fee_outputs);
     374                 :             : 
     375                 :             :     /** How much individual inputs overestimated the bump fees for shared ancestries */
     376                 :             :     void SetBumpFeeDiscount(const CAmount discount);
     377                 :             : 
     378                 :             :     /** Calculates and stores the waste for this result given the cost of change
     379                 :             :      * and the opportunity cost of spending these inputs now vs in the future.
     380                 :             :      * If change exists, waste = change_cost + inputs * (effective_feerate - long_term_feerate) - bump_fee_group_discount
     381                 :             :      * If no change, waste = excess + inputs * (effective_feerate - long_term_feerate) - bump_fee_group_discount
     382                 :             :      * where excess = selected_effective_value - target
     383                 :             :      * change_cost = effective_feerate * change_output_size + long_term_feerate * change_spend_size
     384                 :             :      *
     385                 :             :      * @param[in] min_viable_change The minimum amount necessary to make a change output economic
     386                 :             :      * @param[in] change_cost       The cost of creating a change output and spending it in the future. Only
     387                 :             :      *                              used if there is change, in which case it must be non-negative.
     388                 :             :      * @param[in] change_fee        The fee for creating a change output
     389                 :             :      */
     390                 :             :     void RecalculateWaste(const CAmount min_viable_change, const CAmount change_cost, const CAmount change_fee);
     391                 :             :     [[nodiscard]] CAmount GetWaste() const;
     392                 :             : 
     393                 :             :     /** Tracks that algorithm was able to exhaustively search the entire combination space before hitting limit of tries */
     394                 :             :     void SetAlgoCompleted(bool algo_completed);
     395                 :             : 
     396                 :             :     /** Get m_algo_completed */
     397                 :             :     bool GetAlgoCompleted() const;
     398                 :             : 
     399                 :             :     /** Record the number of selections that were evaluated */
     400                 :             :     void SetSelectionsEvaluated(size_t attempts);
     401                 :             : 
     402                 :             :     /** Get selections_evaluated */
     403                 :             :     size_t GetSelectionsEvaluated() const ;
     404                 :             : 
     405                 :             :     /**
     406                 :             :      * Combines the @param[in] other selection result into 'this' selection result.
     407                 :             :      *
     408                 :             :      * Important note:
     409                 :             :      * There must be no shared 'COutput' among the two selection results being combined.
     410                 :             :      */
     411                 :             :     void Merge(const SelectionResult& other);
     412                 :             : 
     413                 :             :     /** Get m_selected_inputs */
     414                 :             :     const std::set<std::shared_ptr<COutput>>& GetInputSet() const;
     415                 :             :     /** Get the vector of COutputs that will be used to fill in a CTransaction's vin */
     416                 :             :     std::vector<std::shared_ptr<COutput>> GetShuffledInputVector() const;
     417                 :             : 
     418                 :             :     bool operator<(SelectionResult other) const;
     419                 :             : 
     420                 :             :     /** Get the amount for the change output after paying needed fees.
     421                 :             :      *
     422                 :             :      * The change amount is not 100% precise due to discrepancies in fee calculation.
     423                 :             :      * The final change amount (if any) should be corrected after calculating the final tx fees.
     424                 :             :      * When there is a discrepancy, most of the time the final change would be slightly bigger than estimated.
     425                 :             :      *
     426                 :             :      * Following are the possible factors of discrepancy:
     427                 :             :      *  + non-input fees always include segwit flags
     428                 :             :      *  + input fee estimation always include segwit stack size
     429                 :             :      *  + input fees are rounded individually and not collectively, which leads to small rounding errors
     430                 :             :      *  - input counter size is always assumed to be 1vbyte
     431                 :             :      *
     432                 :             :      * @param[in]  min_viable_change  Minimum amount for change output, if change would be less then we forgo change
     433                 :             :      * @param[in]  change_fee         Fees to include change output in the tx
     434                 :             :      * @returns Amount for change output, 0 when there is no change.
     435                 :             :      *
     436                 :             :      */
     437                 :             :     CAmount GetChange(const CAmount min_viable_change, const CAmount change_fee) const;
     438                 :             : 
     439   [ +  -  -  + ]:         486 :     CAmount GetTarget() const { return m_target; }
     440                 :             : 
     441         [ +  - ]:       54960 :     SelectionAlgorithm GetAlgo() const { return m_algo; }
     442                 :             : 
     443   [ -  +  #  #  :      166230 :     int GetWeight() const { return m_weight; }
           #  # ][ +  +  
             +  +  +  - ]
           [ -  +  -  +  
          -  +  +  -  -  
          +  +  -  -  +  
          -  +  +  -  -  
             +  -  +  -  
                      + ]
     444                 :             : };
     445                 :             : 
     446                 :             : util::Result<SelectionResult> SelectCoinsBnB(std::vector<OutputGroup>& utxo_pool, const CAmount& selection_target, const CAmount& cost_of_change,
     447                 :             :                                              int max_selection_weight);
     448                 :             : 
     449                 :             : util::Result<SelectionResult> CoinGrinder(std::vector<OutputGroup>& utxo_pool, const CAmount& selection_target, CAmount change_target, int max_selection_weight);
     450                 :             : 
     451                 :             : /** Select coins by Single Random Draw. OutputGroups are selected randomly from the eligible
     452                 :             :  * outputs until the target is satisfied
     453                 :             :  *
     454                 :             :  * @param[in]  utxo_pool    The positive effective value OutputGroups eligible for selection
     455                 :             :  * @param[in]  target_value The target value to select for
     456                 :             :  * @param[in]  rng The randomness source to shuffle coins
     457                 :             :  * @param[in]  max_selection_weight The maximum allowed weight for a selection result to be valid
     458                 :             :  * @returns If successful, a valid SelectionResult, otherwise, util::Error
     459                 :             :  */
     460                 :             : util::Result<SelectionResult> SelectCoinsSRD(const std::vector<OutputGroup>& utxo_pool, CAmount target_value, CAmount change_fee, FastRandomContext& rng,
     461                 :             :                                              int max_selection_weight);
     462                 :             : 
     463                 :             : // Original coin selection algorithm as a fallback
     464                 :             : util::Result<SelectionResult> KnapsackSolver(std::vector<OutputGroup>& groups, const CAmount& nTargetValue,
     465                 :             :                                              CAmount change_target, FastRandomContext& rng, int max_selection_weight);
     466                 :             : } // namespace wallet
     467                 :             : 
     468                 :             : #endif // BITCOIN_WALLET_COINSELECTION_H
        

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