diff options
Diffstat (limited to 'src/wallet/coinselection.cpp')
| -rw-r--r-- | src/wallet/coinselection.cpp | 59 |
1 files changed, 53 insertions, 6 deletions
diff --git a/src/wallet/coinselection.cpp b/src/wallet/coinselection.cpp index 49e6bac462..b568e90998 100644 --- a/src/wallet/coinselection.cpp +++ b/src/wallet/coinselection.cpp @@ -156,7 +156,7 @@ std::optional<SelectionResult> SelectCoinsBnB(std::vector<OutputGroup>& utxo_poo for (const size_t& i : best_selection) { result.AddInput(utxo_pool.at(i)); } - result.ComputeAndSetWaste(CAmount{0}); + result.ComputeAndSetWaste(cost_of_change, cost_of_change, CAmount{0}); assert(best_waste == result.GetWaste()); return result; @@ -166,6 +166,12 @@ std::optional<SelectionResult> SelectCoinsSRD(const std::vector<OutputGroup>& ut { SelectionResult result(target_value, SelectionAlgorithm::SRD); + // Include change for SRD as we want to avoid making really small change if the selection just + // barely meets the target. Just use the lower bound change target instead of the randomly + // generated one, since SRD will result in a random change amount anyway; avoid making the + // target needlessly large. + target_value += CHANGE_LOWER; + std::vector<size_t> indexes; indexes.resize(utxo_pool.size()); std::iota(indexes.begin(), indexes.end(), 0); @@ -389,20 +395,26 @@ CAmount GetSelectionWaste(const std::set<COutput>& inputs, CAmount change_cost, return waste; } -CAmount GenerateChangeTarget(CAmount payment_value, FastRandomContext& rng) +CAmount GenerateChangeTarget(const CAmount payment_value, const CAmount change_fee, FastRandomContext& rng) { if (payment_value <= CHANGE_LOWER / 2) { - return CHANGE_LOWER; + return change_fee + CHANGE_LOWER; } else { // random value between 50ksat and min (payment_value * 2, 1milsat) const auto upper_bound = std::min(payment_value * 2, CHANGE_UPPER); - return rng.randrange(upper_bound - CHANGE_LOWER) + CHANGE_LOWER; + return change_fee + rng.randrange(upper_bound - CHANGE_LOWER) + CHANGE_LOWER; } } -void SelectionResult::ComputeAndSetWaste(CAmount change_cost) +void SelectionResult::ComputeAndSetWaste(const CAmount min_viable_change, const CAmount change_cost, const CAmount change_fee) { - m_waste = GetSelectionWaste(m_selected_inputs, change_cost, m_target, m_use_effective); + const CAmount change = GetChange(min_viable_change, change_fee); + + if (change > 0) { + m_waste = GetSelectionWaste(m_selected_inputs, change_cost, m_target, m_use_effective); + } else { + m_waste = GetSelectionWaste(m_selected_inputs, 0, m_target, m_use_effective); + } } CAmount SelectionResult::GetWaste() const @@ -415,6 +427,11 @@ CAmount SelectionResult::GetSelectedValue() const return std::accumulate(m_selected_inputs.cbegin(), m_selected_inputs.cend(), CAmount{0}, [](CAmount sum, const auto& coin) { return sum + coin.txout.nValue; }); } +CAmount SelectionResult::GetSelectedEffectiveValue() const +{ + return std::accumulate(m_selected_inputs.cbegin(), m_selected_inputs.cend(), CAmount{0}, [](CAmount sum, const auto& coin) { return sum + coin.GetEffectiveValue(); }); +} + void SelectionResult::Clear() { m_selected_inputs.clear(); @@ -427,6 +444,16 @@ void SelectionResult::AddInput(const OutputGroup& group) m_use_effective = !group.m_subtract_fee_outputs; } +void SelectionResult::Merge(const SelectionResult& other) +{ + m_target += other.m_target; + m_use_effective |= other.m_use_effective; + if (m_algo == SelectionAlgorithm::MANUAL) { + m_algo = other.m_algo; + } + util::insert(m_selected_inputs, other.m_selected_inputs); +} + const std::set<COutput>& SelectionResult::GetInputSet() const { return m_selected_inputs; @@ -464,4 +491,24 @@ std::string GetAlgorithmName(const SelectionAlgorithm algo) } assert(false); } + +CAmount SelectionResult::GetChange(const CAmount min_viable_change, const CAmount change_fee) const +{ + // change = SUM(inputs) - SUM(outputs) - fees + // 1) With SFFO we don't pay any fees + // 2) Otherwise we pay all the fees: + // - input fees are covered by GetSelectedEffectiveValue() + // - non_input_fee is included in m_target + // - change_fee + const CAmount change = m_use_effective + ? GetSelectedEffectiveValue() - m_target - change_fee + : GetSelectedValue() - m_target; + + if (change < min_viable_change) { + return 0; + } + + return change; +} + } // namespace wallet |