1 files changed, 89 insertions, 0 deletions
diff --git a/src/wallet/fees.cpp b/src/wallet/fees.cpp
new file mode 100644
index 0000000000..76eeeeda05
--- /dev/null
+++ b/src/wallet/fees.cpp
@@ -0,0 +1,89 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2017 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "wallet/fees.h"
+
+#include "policy/policy.h"
+#include "txmempool.h"
+#include "util.h"
+#include "validation.h"
+#include "wallet/coincontrol.h"
+#include "wallet/wallet.h"
+
+
+CAmount GetRequiredFee(unsigned int nTxBytes)
+{
+    return std::max(CWallet::minTxFee.GetFee(nTxBytes), ::minRelayTxFee.GetFee(nTxBytes));
+}
+
+
+CAmount GetMinimumFee(unsigned int nTxBytes, const CCoinControl& coin_control, const CTxMemPool& pool, const CBlockPolicyEstimator& estimator, FeeCalculation *feeCalc)
+{
+    /* User control of how to calculate fee uses the following parameter precedence:
+       1. coin_control.m_feerate
+       2. coin_control.m_confirm_target
+       3. payTxFee (user-set global variable)
+       4. nTxConfirmTarget (user-set global variable)
+       The first parameter that is set is used.
+    */
+    CAmount fee_needed;
+    if (coin_control.m_feerate) { // 1.
+        fee_needed = coin_control.m_feerate->GetFee(nTxBytes);
+        if (feeCalc) feeCalc->reason = FeeReason::PAYTXFEE;
+        // Allow to override automatic min/max check over coin control instance
+        if (coin_control.fOverrideFeeRate) return fee_needed;
+    }
+    else if (!coin_control.m_confirm_target && ::payTxFee != CFeeRate(0)) { // 3. TODO: remove magic value of 0 for global payTxFee
+        fee_needed = ::payTxFee.GetFee(nTxBytes);
+        if (feeCalc) feeCalc->reason = FeeReason::PAYTXFEE;
+    }
+    else { // 2. or 4.
+        // We will use smart fee estimation
+        unsigned int target = coin_control.m_confirm_target ? *coin_control.m_confirm_target : ::nTxConfirmTarget;
+        // By default estimates are economical iff we are signaling opt-in-RBF
+        bool conservative_estimate = !coin_control.signalRbf;
+        // Allow to override the default fee estimate mode over the CoinControl instance
+        if (coin_control.m_fee_mode == FeeEstimateMode::CONSERVATIVE) conservative_estimate = true;
+        else if (coin_control.m_fee_mode == FeeEstimateMode::ECONOMICAL) conservative_estimate = false;
+
+        fee_needed = estimator.estimateSmartFee(target, feeCalc, conservative_estimate).GetFee(nTxBytes);
+        if (fee_needed == 0) {
+            // if we don't have enough data for estimateSmartFee, then use fallbackFee
+            fee_needed = CWallet::fallbackFee.GetFee(nTxBytes);
+            if (feeCalc) feeCalc->reason = FeeReason::FALLBACK;
+        }
+        // Obey mempool min fee when using smart fee estimation
+        CAmount min_mempool_fee = pool.GetMinFee(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFee(nTxBytes);
+        if (fee_needed < min_mempool_fee) {
+            fee_needed = min_mempool_fee;
+            if (feeCalc) feeCalc->reason = FeeReason::MEMPOOL_MIN;
+        }
+    }
+
+    // prevent user from paying a fee below minRelayTxFee or minTxFee
+    CAmount required_fee = GetRequiredFee(nTxBytes);
+    if (required_fee > fee_needed) {
+        fee_needed = required_fee;
+        if (feeCalc) feeCalc->reason = FeeReason::REQUIRED;
+    }
+    // But always obey the maximum
+    if (fee_needed > maxTxFee) {
+        fee_needed = maxTxFee;
+        if (feeCalc) feeCalc->reason = FeeReason::MAXTXFEE;
+    }
+    return fee_needed;
+}
+
+
+CFeeRate GetDiscardRate(const CBlockPolicyEstimator& estimator)
+{
+    unsigned int highest_target = estimator.HighestTargetTracked(FeeEstimateHorizon::LONG_HALFLIFE);
+    CFeeRate discard_rate = estimator.estimateSmartFee(highest_target, nullptr /* FeeCalculation */, false /* conservative */);
+    // Don't let discard_rate be greater than longest possible fee estimate if we get a valid fee estimate
+    discard_rate = (discard_rate == CFeeRate(0)) ? CWallet::m_discard_rate : std::min(discard_rate, CWallet::m_discard_rate);
+    // Discard rate must be at least dustRelayFee
+    discard_rate = std::max(discard_rate, ::dustRelayFee);
+    return discard_rate;
+}