1 files changed, 32 insertions, 28 deletions

diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 3e2d1794d8..fbb87353c1 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -269,6 +269,9 @@ public:
     bool IsCoinBase() const { return tx->IsCoinBase(); }
 };
 
+//Get the marginal bytes of spending the specified output
+int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* pwallet);
+
 /** 
  * A transaction with a bunch of additional info that only the owner cares about.
  * It includes any unrecorded transactions needed to link it back to the block chain.
@@ -462,6 +465,12 @@ public:
     CAmount GetAvailableWatchOnlyCredit(const bool fUseCache=true) const;
     CAmount GetChange() const;
 
+    // Get the marginal bytes if spending the specified output from this transaction
+    int GetSpendSize(unsigned int out) const
+    {
+        return CalculateMaximumSignedInputSize(tx->vout[out], pwallet);
+    }
+
     void GetAmounts(std::list<COutputEntry>& listReceived,
                     std::list<COutputEntry>& listSent, CAmount& nFee, std::string& strSentAccount, const isminefilter& filter) const;
 
@@ -525,6 +534,9 @@ public:
     int i;
     int nDepth;
 
+    /** Pre-computed estimated size of this output as a fully-signed input in a transaction. Can be -1 if it could not be calculated */
+    int nInputBytes;
+
     /** Whether we have the private keys to spend this output */
     bool fSpendable;
 
@@ -540,7 +552,12 @@ public:
 
     COutput(const CWalletTx *txIn, int iIn, int nDepthIn, bool fSpendableIn, bool fSolvableIn, bool fSafeIn)
     {
-        tx = txIn; i = iIn; nDepth = nDepthIn; fSpendable = fSpendableIn; fSolvable = fSolvableIn; fSafe = fSafeIn;
+        tx = txIn; i = iIn; nDepth = nDepthIn; fSpendable = fSpendableIn; fSolvable = fSolvableIn; fSafe = fSafeIn; nInputBytes = -1;
+        // If known and signable by the given wallet, compute nInputBytes
+        // Failure will keep this value -1
+        if (fSpendable && tx) {
+            nInputBytes = tx->GetSpendSize(i);
+        }
     }
 
     std::string ToString() const;
@@ -981,8 +998,14 @@ public:
     void ListAccountCreditDebit(const std::string& strAccount, std::list<CAccountingEntry>& entries);
     bool AddAccountingEntry(const CAccountingEntry&);
     bool AddAccountingEntry(const CAccountingEntry&, CWalletDB *pwalletdb);
-    template <typename ContainerType>
-    bool DummySignTx(CMutableTransaction &txNew, const ContainerType &coins) const;
+    bool DummySignTx(CMutableTransaction &txNew, const std::set<CTxOut> &txouts) const
+    {
+        std::vector<CTxOut> v_txouts(txouts.size());
+        std::copy(txouts.begin(), txouts.end(), v_txouts.begin());
+        return DummySignTx(txNew, v_txouts);
+    }
+    bool DummySignTx(CMutableTransaction &txNew, const std::vector<CTxOut> &txouts) const;
+    bool DummySignInput(CTxIn &tx_in, const CTxOut &txout) const;
 
     static CFeeRate minTxFee;
     static CFeeRate fallbackFee;
@@ -1227,31 +1250,6 @@ public:
     }
 };
 
-// Helper for producing a bunch of max-sized low-S signatures (eg 72 bytes)
-// ContainerType is meant to hold pair<CWalletTx *, int>, and be iterable
-// so that each entry corresponds to each vIn, in order.
-template <typename ContainerType>
-bool CWallet::DummySignTx(CMutableTransaction &txNew, const ContainerType &coins) const
-{
-    // Fill in dummy signatures for fee calculation.
-    int nIn = 0;
-    for (const auto& coin : coins)
-    {
-        const CScript& scriptPubKey = coin.txout.scriptPubKey;
-        SignatureData sigdata;
-
-        if (!ProduceSignature(DummySignatureCreator(this), scriptPubKey, sigdata))
-        {
-            return false;
-        } else {
-            UpdateTransaction(txNew, nIn, sigdata);
-        }
-
-        nIn++;
-    }
-    return true;
-}
-
 OutputType ParseOutputType(const std::string& str, OutputType default_type = OUTPUT_TYPE_DEFAULT);
 const std::string& FormatOutputType(OutputType type);
 
@@ -1299,4 +1297,10 @@ public:
     }
 };
 
+// Calculate the size of the transaction assuming all signatures are max size
+// Use DummySignatureCreator, which inserts 72 byte signatures everywhere.
+// NOTE: this requires that all inputs must be in mapWallet (eg the tx should
+// be IsAllFromMe).
+int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet);
+int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, const std::vector<CTxOut>& txouts);
 #endif // BITCOIN_WALLET_WALLET_H