diff options
| -rw-r--r-- | src/wallet/wallet.cpp | 221 |
1 files changed, 104 insertions, 117 deletions
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp index c1e58a949f..303823695e 100644 --- a/src/wallet/wallet.cpp +++ b/src/wallet/wallet.cpp @@ -2804,7 +2804,6 @@ bool CWallet::CreateTransactionInternal( CAmount nValue = 0; const OutputType change_type = TransactionChangeType(coin_control.m_change_type ? *coin_control.m_change_type : m_default_change_type, vecSend); ReserveDestination reservedest(this, change_type); - int nChangePosRequest = nChangePosInOut; unsigned int nSubtractFeeFromAmount = 0; for (const auto& recipient : vecSend) { @@ -2909,151 +2908,139 @@ bool CWallet::CreateTransactionInternal( coin_selection_params.m_change_fee = coin_selection_params.m_effective_feerate.GetFee(coin_selection_params.change_output_size); coin_selection_params.m_cost_of_change = coin_selection_params.m_discard_feerate.GetFee(coin_selection_params.change_spend_size) + coin_selection_params.m_change_fee; - nFeeRet = 0; - CAmount nValueIn = 0; - coin_selection_params.m_subtract_fee_outputs = nSubtractFeeFromAmount != 0; // If we are doing subtract fee from recipient, don't use effective values - // Start with no fee and loop until there is enough fee - while (true) + + // vouts to the payees + if (!coin_selection_params.m_subtract_fee_outputs) { + coin_selection_params.tx_noinputs_size = 11; // Static vsize overhead + outputs vsize. 4 nVersion, 4 nLocktime, 1 input count, 1 output count, 1 witness overhead (dummy, flag, stack size) + } + for (const auto& recipient : vecSend) { - nChangePosInOut = nChangePosRequest; - txNew.vin.clear(); - txNew.vout.clear(); + CTxOut txout(recipient.nAmount, recipient.scriptPubKey); - // vouts to the payees + // Include the fee cost for outputs. if (!coin_selection_params.m_subtract_fee_outputs) { - coin_selection_params.tx_noinputs_size = 11; // Static vsize overhead + outputs vsize. 4 nVersion, 4 nLocktime, 1 input count, 1 output count, 1 witness overhead (dummy, flag, stack size) + coin_selection_params.tx_noinputs_size += ::GetSerializeSize(txout, PROTOCOL_VERSION); } - for (const auto& recipient : vecSend) + + if (IsDust(txout, chain().relayDustFee())) { - CTxOut txout(recipient.nAmount, recipient.scriptPubKey); + error = _("Transaction amount too small"); + return false; + } + txNew.vout.push_back(txout); + } - // Include the fee cost for outputs. - if (!coin_selection_params.m_subtract_fee_outputs) { - coin_selection_params.tx_noinputs_size += ::GetSerializeSize(txout, PROTOCOL_VERSION); - } + // Include the fees for things that aren't inputs, excluding the change output + const CAmount not_input_fees = coin_selection_params.m_effective_feerate.GetFee(coin_selection_params.tx_noinputs_size); + CAmount nValueToSelect = nValue + not_input_fees; - if (IsDust(txout, chain().relayDustFee())) - { - error = _("Transaction amount too small"); - return false; - } - txNew.vout.push_back(txout); - } + // Choose coins to use + CAmount inputs_sum = 0; + setCoins.clear(); + if (!SelectCoins(vAvailableCoins, /* nTargetValue */ nValueToSelect, setCoins, inputs_sum, coin_control, coin_selection_params)) + { + error = _("Insufficient funds"); + return false; + } - // Include the fees for things that aren't inputs, excluding the change output - const CAmount not_input_fees = coin_selection_params.m_effective_feerate.GetFee(coin_selection_params.tx_noinputs_size); - CAmount nValueToSelect = nValue + not_input_fees; + // Always make a change output + // We will reduce the fee from this change output later, and remove the output if it is too small. + const CAmount change_and_fee = inputs_sum - nValue; + assert(change_and_fee >= 0); + CTxOut newTxOut(change_and_fee, scriptChange); - // Choose coins to use - nValueIn = 0; - setCoins.clear(); - if (!SelectCoins(vAvailableCoins, /* nTargetValue */ nValueToSelect, setCoins, nValueIn, coin_control, coin_selection_params)) - { - error = _("Insufficient funds"); - return false; - } + if (nChangePosInOut == -1) + { + // Insert change txn at random position: + nChangePosInOut = GetRandInt(txNew.vout.size()+1); + } + else if ((unsigned int)nChangePosInOut > txNew.vout.size()) + { + error = _("Change index out of range"); + return false; + } - // Always make a change output - // We will reduce the fee from this change output later, and remove the output if it is too small. - const CAmount change_and_fee = nValueIn - nValue; - assert(change_and_fee >= 0); - CTxOut newTxOut(change_and_fee, scriptChange); + assert(nChangePosInOut != -1); + auto change_position = txNew.vout.insert(txNew.vout.begin() + nChangePosInOut, newTxOut); - if (nChangePosInOut == -1) - { - // Insert change txn at random position: - nChangePosInOut = GetRandInt(txNew.vout.size()+1); - } - else if ((unsigned int)nChangePosInOut > txNew.vout.size()) - { - error = _("Change index out of range"); - return false; - } + // Dummy fill vin for maximum size estimation + // + for (const auto& coin : setCoins) { + txNew.vin.push_back(CTxIn(coin.outpoint,CScript())); + } - assert(nChangePosInOut != -1); - auto change_position = txNew.vout.insert(txNew.vout.begin() + nChangePosInOut, newTxOut); + // Calculate the transaction fee + tx_sizes = CalculateMaximumSignedTxSize(CTransaction(txNew), this, coin_control.fAllowWatchOnly); + nBytes = tx_sizes.first; + if (nBytes < 0) { + error = _("Signing transaction failed"); + return false; + } + nFeeRet = coin_selection_params.m_effective_feerate.GetFee(nBytes); - // Dummy fill vin for maximum size estimation - // - for (const auto& coin : setCoins) { - txNew.vin.push_back(CTxIn(coin.outpoint,CScript())); - } + // Subtract fee from the change output if not subtrating it from recipient outputs + CAmount fee_needed = nFeeRet; + if (nSubtractFeeFromAmount == 0) { + change_position->nValue -= fee_needed; + } - // Calculate the transaction fee + // We want to drop the change to fees if: + // 1. The change output would be dust + // 2. The change is within the (almost) exact match window, i.e. it is less than or equal to the cost of the change output (cost_of_change) + CAmount change_amount = change_position->nValue; + if (IsDust(*change_position, coin_selection_params.m_discard_feerate) || change_amount <= coin_selection_params.m_cost_of_change) + { + nChangePosInOut = -1; + change_amount = 0; + txNew.vout.erase(change_position); + + // Because we have dropped this change, the tx size and required fee will be different, so let's recalculate those tx_sizes = CalculateMaximumSignedTxSize(CTransaction(txNew), this, coin_control.fAllowWatchOnly); nBytes = tx_sizes.first; - if (nBytes < 0) { - error = _("Signing transaction failed"); - return false; - } - nFeeRet = coin_selection_params.m_effective_feerate.GetFee(nBytes); + fee_needed = coin_selection_params.m_effective_feerate.GetFee(nBytes); + } - // Subtract fee from the change output if not subtrating it from recipient outputs - CAmount fee_needed = nFeeRet; - if (nSubtractFeeFromAmount == 0) { - change_position->nValue -= fee_needed; - } + // Update nFeeRet in case fee_needed changed due to dropping the change output + if (fee_needed <= change_and_fee - change_amount) { + nFeeRet = change_and_fee - change_amount; + } - // We want to drop the change to fees if: - // 1. The change output would be dust - // 2. The change is within the (almost) exact match window, i.e. it is less than or equal to the cost of the change output (cost_of_change) - CAmount change_amount = change_position->nValue; - if (IsDust(*change_position, coin_selection_params.m_discard_feerate) || change_amount <= coin_selection_params.m_cost_of_change) + // Reduce output values for subtractFeeFromAmount + if (nSubtractFeeFromAmount != 0) { + CAmount to_reduce = fee_needed + change_amount - change_and_fee; + int i = 0; + bool fFirst = true; + for (const auto& recipient : vecSend) { - nChangePosInOut = -1; - change_amount = 0; - txNew.vout.erase(change_position); - - // Because we have dropped this change, the tx size and required fee will be different, so let's recalculate those - tx_sizes = CalculateMaximumSignedTxSize(CTransaction(txNew), this, coin_control.fAllowWatchOnly); - nBytes = tx_sizes.first; - fee_needed = coin_selection_params.m_effective_feerate.GetFee(nBytes); - } - - // If the fee is covered, there's no need to loop or subtract from recipients - if (fee_needed <= change_and_fee - change_amount) { - nFeeRet = change_and_fee - change_amount; - break; - } + if (i == nChangePosInOut) { + ++i; + } + CTxOut& txout = txNew.vout[i]; - // Reduce output values for subtractFeeFromAmount - if (nSubtractFeeFromAmount != 0) { - CAmount to_reduce = fee_needed + change_amount - change_and_fee; - int i = 0; - bool fFirst = true; - for (const auto& recipient : vecSend) + if (recipient.fSubtractFeeFromAmount) { - if (i == nChangePosInOut) { - ++i; - } - CTxOut& txout = txNew.vout[i]; + txout.nValue -= to_reduce / nSubtractFeeFromAmount; // Subtract fee equally from each selected recipient - if (recipient.fSubtractFeeFromAmount) + if (fFirst) // first receiver pays the remainder not divisible by output count { - txout.nValue -= to_reduce / nSubtractFeeFromAmount; // Subtract fee equally from each selected recipient - - if (fFirst) // first receiver pays the remainder not divisible by output count - { - fFirst = false; - txout.nValue -= to_reduce % nSubtractFeeFromAmount; - } + fFirst = false; + txout.nValue -= to_reduce % nSubtractFeeFromAmount; + } - // Error if this output is reduced to be below dust - if (IsDust(txout, chain().relayDustFee())) { - if (txout.nValue < 0) { - error = _("The transaction amount is too small to pay the fee"); - } else { - error = _("The transaction amount is too small to send after the fee has been deducted"); - } - return false; + // Error if this output is reduced to be below dust + if (IsDust(txout, chain().relayDustFee())) { + if (txout.nValue < 0) { + error = _("The transaction amount is too small to pay the fee"); + } else { + error = _("The transaction amount is too small to send after the fee has been deducted"); } + return false; } - ++i; } - nFeeRet = fee_needed; - break; // The fee has been deducted from the recipients, nothing left to do here + ++i; } + nFeeRet = fee_needed; } // Give up if change keypool ran out and change is required |