Un-hardcode TX_FEE constants

Allow setting of MIN_TX_FEE / MIN_RELAY_TX_FEE with
-mintxfee / -mintxrelayfee

Default values are the same (0.0001 BTC).

5 files changed, 53 insertions, 40 deletions

diff --git a/src/init.cpp b/src/init.cpp
index 3845cfad81..058b6a06e5 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -583,6 +583,28 @@ bool AppInit2(boost::thread_group& threadGroup)
     const char* pszP2SH = "/P2SH/";
     COINBASE_FLAGS << std::vector<unsigned char>(pszP2SH, pszP2SH+strlen(pszP2SH));
 
+    // Fee-per-kilobyte amount considered the same as "free"
+    // If you are mining, be careful setting this:
+    // if you set it to zero then
+    // a transaction spammer can cheaply fill blocks using
+    // 1-satoshi-fee transactions. It should be set above the real
+    // cost to you of processing a transaction.
+    if (mapArgs.count("-mintxfee"))
+    {
+        int64 n = 0;
+        if (ParseMoney(mapArgs["-mintxfee"], n) && n > 0)
+            CTransaction::nMinTxFee = n;
+        else
+            return InitError(strprintf(_("Invalid amount for -mintxfee=<amount>: '%s'"), mapArgs["-mintxfee"].c_str()));
+    }
+    if (mapArgs.count("-minrelaytxfee"))
+    {
+        int64 n = 0;
+        if (ParseMoney(mapArgs["-minrelaytxfee"], n) && n > 0)
+            CTransaction::nMinRelayTxFee = n;
+        else
+            return InitError(strprintf(_("Invalid amount for -minrelaytxfee=<amount>: '%s'"), mapArgs["-minrelaytxfee"].c_str()));
+    }
 
     if (mapArgs.count("-paytxfee"))
     {
diff --git a/src/main.cpp b/src/main.cpp
index d0d6a99eb1..91e84aefcc 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -48,6 +48,11 @@ bool fBenchmark = false;
 bool fTxIndex = false;
 unsigned int nCoinCacheSize = 5000;
 
+/** Fees smaller than this (in satoshi) are considered zero fee (for transaction creation) */
+int64 CTransaction::nMinTxFee = 10000;  // Override with -mintxfee
+/** Fees smaller than this (in satoshi) are considered zero fee (for relaying) */
+int64 CTransaction::nMinRelayTxFee = 10000;
+
 CMedianFilter<int> cPeerBlockCounts(8, 0); // Amount of blocks that other nodes claim to have
 
 map<uint256, CBlock*> mapOrphanBlocks;
@@ -352,9 +357,22 @@ unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans)
 
 //////////////////////////////////////////////////////////////////////////////
 //
-// CTransaction
+// CTransaction / CTxOut
 //
 
+bool CTxOut::IsDust() const
+{
+    // "Dust" is defined in terms of CTransaction::nMinRelayTxFee,
+    // which has units satoshis-per-kilobyte.
+    // If you'd pay more than 1/3 in fees
+    // to spend something, then we consider it dust.
+    // A typical txout is 33 bytes big, and will
+    // need a CTxIn of at least 148 bytes to spend,
+    // so dust is a txout less than 54 uBTC
+    // (5430 satoshis) with default nMinRelayTxFee
+    return ((nValue*1000)/(3*((int)GetSerializeSize(SER_DISK,0)+148)) < CTransaction::nMinRelayTxFee);
+}
+
 bool CTransaction::IsStandard() const
 {
     if (nVersion > CTransaction::CURRENT_VERSION)
@@ -574,8 +592,8 @@ bool CTransaction::CheckTransaction(CValidationState &state) const
 int64 CTransaction::GetMinFee(unsigned int nBlockSize, bool fAllowFree,
                               enum GetMinFee_mode mode) const
 {
-    // Base fee is either MIN_TX_FEE or MIN_RELAY_TX_FEE
-    int64 nBaseFee = (mode == GMF_RELAY) ? MIN_RELAY_TX_FEE : MIN_TX_FEE;
+    // Base fee is either nMinTxFee or nMinRelayTxFee
+    int64 nBaseFee = (mode == GMF_RELAY) ? nMinRelayTxFee : nMinTxFee;
 
     unsigned int nBytes = ::GetSerializeSize(*this, SER_NETWORK, PROTOCOL_VERSION);
     unsigned int nNewBlockSize = nBlockSize + nBytes;
@@ -598,7 +616,7 @@ int64 CTransaction::GetMinFee(unsigned int nBlockSize, bool fAllowFree,
         }
     }
 
-    // To limit dust spam, require MIN_TX_FEE/MIN_RELAY_TX_FEE if any output is less than 0.01
+    // To limit dust spam, require base fee if any output is less than 0.01
     if (nMinFee < nBaseFee)
     {
         BOOST_FOREACH(const CTxOut& txout, vout)
@@ -746,7 +764,7 @@ bool CTxMemPool::accept(CValidationState &state, CTransaction &tx, bool fCheckIn
         // Continuously rate-limit free transactions
         // This mitigates 'penny-flooding' -- sending thousands of free transactions just to
         // be annoying or make others' transactions take longer to confirm.
-        if (fLimitFree && nFees < MIN_RELAY_TX_FEE)
+        if (fLimitFree && nFees < CTransaction::nMinRelayTxFee)
         {
             static double dFreeCount;
             static int64 nLastTime;
@@ -4184,15 +4202,6 @@ CBlockTemplate* CreateNewBlock(CReserveKey& reservekey)
     unsigned int nBlockMinSize = GetArg("-blockminsize", 0);
     nBlockMinSize = std::min(nBlockMaxSize, nBlockMinSize);
 
-    // Fee-per-kilobyte amount considered the same as "free"
-    // Be careful setting this: if you set it to zero then
-    // a transaction spammer can cheaply fill blocks using
-    // 1-satoshi-fee transactions. It should be set above the real
-    // cost to you of processing a transaction.
-    int64 nMinTxFee = MIN_TX_FEE;
-    if (mapArgs.count("-mintxfee"))
-        ParseMoney(mapArgs["-mintxfee"], nMinTxFee);
-
     // Collect memory pool transactions into the block
     int64 nFees = 0;
     {
@@ -4310,7 +4319,7 @@ CBlockTemplate* CreateNewBlock(CReserveKey& reservekey)
                 continue;
 
             // Skip free transactions if we're past the minimum block size:
-            if (fSortedByFee && (dFeePerKb < nMinTxFee) && (nBlockSize + nTxSize >= nBlockMinSize))
+            if (fSortedByFee && (dFeePerKb < CTransaction::nMinTxFee) && (nBlockSize + nTxSize >= nBlockMinSize))
                 continue;
 
             // Prioritize by fee once past the priority size or we run out of high-priority
diff --git a/src/main.h b/src/main.h
index 8c1e6d265c..905b9fbacb 100644
--- a/src/main.h
+++ b/src/main.h
@@ -44,10 +44,6 @@ static const unsigned int BLOCKFILE_CHUNK_SIZE = 0x1000000; // 16 MiB
 static const unsigned int UNDOFILE_CHUNK_SIZE = 0x100000; // 1 MiB
 /** Fake height value used in CCoins to signify they are only in the memory pool (since 0.8) */
 static const unsigned int MEMPOOL_HEIGHT = 0x7FFFFFFF;
-/** Fees smaller than this (in satoshi) are considered zero fee (for transaction creation) */
-static const int64 MIN_TX_FEE = 10000;
-/** Fees smaller than this (in satoshi) are considered zero fee (for relaying) */
-static const int64 MIN_RELAY_TX_FEE = 10000;
 /** No amount larger than this (in satoshi) is valid */
 static const int64 MAX_MONEY = 21000000 * COIN;
 inline bool MoneyRange(int64 nValue) { return (nValue >= 0 && nValue <= MAX_MONEY); }
@@ -439,23 +435,7 @@ public:
         return !(a == b);
     }
 
-    size_t size() const
-    {
-        return sizeof(nValue)+scriptPubKey.size();
-    }
-
-    bool IsDust() const
-    {
-        // "Dust" is defined in terms of MIN_RELAY_TX_FEE, which
-        // has units satoshis-per-kilobyte.
-        // If you'd pay more than 1/3 in fees
-        // to spend something, then we consider it dust.
-        // A typical txout is 32 bytes big, and will
-        // need a CTxIn of at least 148 bytes to spend, 
-        // so dust is a txout less than 54 uBTC
-        // (5400 satoshis)
-        return ((nValue*1000)/(3*(size()+148)) < MIN_RELAY_TX_FEE);
-    }
+    bool IsDust() const;
 
     std::string ToString() const
     {
@@ -485,6 +465,8 @@ enum GetMinFee_mode
 class CTransaction
 {
 public:
+    static int64 nMinTxFee;
+    static int64 nMinRelayTxFee;
     static const int CURRENT_VERSION=1;
     int nVersion;
     std::vector<CTxIn> vin;
diff --git a/src/qt/bitcoin.cpp b/src/qt/bitcoin.cpp
index 25448ea8cf..5bd808a89e 100644
--- a/src/qt/bitcoin.cpp
+++ b/src/qt/bitcoin.cpp
@@ -69,7 +69,7 @@ static bool ThreadSafeAskFee(int64 nFeeRequired)
 {
     if(!guiref)
         return false;
-    if(nFeeRequired < MIN_TX_FEE || nFeeRequired <= nTransactionFee || fDaemon)
+    if(nFeeRequired < CTransaction::nMinTxFee || nFeeRequired <= nTransactionFee || fDaemon)
         return true;
 
     bool payFee = false;
diff --git a/src/wallet.cpp b/src/wallet.cpp
index 65d2c3b68e..532a73201a 100644
--- a/src/wallet.cpp
+++ b/src/wallet.cpp
@@ -1197,12 +1197,12 @@ bool CWallet::CreateTransaction(const vector<pair<CScript, int64> >& vecSend,
                 }
 
                 int64 nChange = nValueIn - nValue - nFeeRet;
-                // if sub-cent change is required, the fee must be raised to at least MIN_TX_FEE
+                // if sub-cent change is required, the fee must be raised to at least nMinTxFee
                 // or until nChange becomes zero
                 // NOTE: this depends on the exact behaviour of GetMinFee
-                if (nFeeRet < MIN_TX_FEE && nChange > 0 && nChange < CENT)
+                if (nFeeRet < CTransaction::nMinTxFee && nChange > 0 && nChange < CENT)
                 {
-                    int64 nMoveToFee = min(nChange, MIN_TX_FEE - nFeeRet);
+                    int64 nMoveToFee = min(nChange, CTransaction::nMinTxFee - nFeeRet);
                     nChange -= nMoveToFee;
                     nFeeRet += nMoveToFee;
                 }