Spent per txout

Change some internal data structures to keep track of spentness of each wallet transaction output separately, to support partially-spent transactions:
* an update to the data structures (vfSpent in CWalletTx instead of fSpent)
* a backward-compatible update to the wallet disk format. Old clients reading back an updated wallet will ignore partially spent transactions when creating new ones, and may report a wrong balance, though.
* some helper functions (CWalletTx: IsSpent, MarkSpent, MarkDirty to reset cached values, GetAvailableCredit which only counts unredeemed outputs)

2 files changed, 147 insertions, 43 deletions

diff --git a/main.cpp b/main.cpp
index bfc45af28e..6741d55861 100644
--- a/main.cpp
+++ b/main.cpp
@@ -136,11 +136,7 @@ bool AddToWallet(const CWalletTx& wtxIn)
                 wtx.fFromMe = wtxIn.fFromMe;
                 fUpdated = true;
             }
-            if (wtxIn.fSpent && wtxIn.fSpent != wtx.fSpent)
-            {
-                wtx.fSpent = wtxIn.fSpent;
-                fUpdated = true;
-            }
+            fUpdated |= wtx.UpdateSpent(wtxIn.vfSpent);
         }
 
         //// debug print
@@ -221,10 +217,10 @@ void WalletUpdateSpent(const COutPoint& prevout)
         if (mi != mapWallet.end())
         {
             CWalletTx& wtx = (*mi).second;
-            if (!wtx.fSpent && wtx.vout[prevout.n].IsMine())
+            if (!wtx.IsSpent(prevout.n) && wtx.vout[prevout.n].IsMine())
             {
                 printf("WalletUpdateSpent found spent coin %sbc %s\n", FormatMoney(wtx.GetCredit()).c_str(), wtx.GetHash().ToString().c_str());
-                wtx.fSpent = true;
+                wtx.MarkSpent(prevout.n);
                 wtx.WriteToDisk();
                 vWalletUpdated.push_back(prevout.hash);
             }
@@ -939,34 +935,34 @@ void ReacceptWalletTransactions()
         foreach(PAIRTYPE(const uint256, CWalletTx)& item, mapWallet)
         {
             CWalletTx& wtx = item.second;
-            if (wtx.fSpent && wtx.IsCoinBase())
+            if (wtx.IsCoinBase() && wtx.IsSpent(0))
                 continue;
 
             CTxIndex txindex;
+            bool fUpdated = false;
             if (txdb.ReadTxIndex(wtx.GetHash(), txindex))
             {
                 // Update fSpent if a tx got spent somewhere else by a copy of wallet.dat
-                if (!wtx.fSpent)
+                if (txindex.vSpent.size() != wtx.vout.size())
                 {
-                    if (txindex.vSpent.size() != wtx.vout.size())
-                    {
-                        printf("ERROR: ReacceptWalletTransactions() : txindex.vSpent.size() %d != wtx.vout.size() %d\n", txindex.vSpent.size(), wtx.vout.size());
-                        continue;
-                    }
-                    for (int i = 0; i < txindex.vSpent.size(); i++)
-                    {
-                        if (!txindex.vSpent[i].IsNull() && wtx.vout[i].IsMine())
-                        {
-                            wtx.fSpent = true;
-                            vMissingTx.push_back(txindex.vSpent[i]);
-                        }
-                    }
-                    if (wtx.fSpent)
+                    printf("ERROR: ReacceptWalletTransactions() : txindex.vSpent.size() %d != wtx.vout.size() %d\n", txindex.vSpent.size(), wtx.vout.size());
+                    continue;
+                }
+                for (int i = 0; i < txindex.vSpent.size(); i++)
+                {
+                    if (!txindex.vSpent[i].IsNull() && wtx.vout[i].IsMine())
                     {
-                        printf("ReacceptWalletTransactions found spent coin %sbc %s\n", FormatMoney(wtx.GetCredit()).c_str(), wtx.GetHash().ToString().c_str());
-                        wtx.WriteToDisk();
+                        wtx.MarkSpent(i);
+                        fUpdated = true;
+                        vMissingTx.push_back(txindex.vSpent[i]);
                     }
                 }
+                if (fUpdated)
+                {
+                    printf("ReacceptWalletTransactions found spent coin %sbc %s\n", FormatMoney(wtx.GetCredit()).c_str(), wtx.GetHash().ToString().c_str());
+                    wtx.MarkDirty();
+                    wtx.WriteToDisk();
+                }
             }
             else
             {
@@ -3732,9 +3728,9 @@ int64 GetBalance()
         for (map<uint256, CWalletTx>::iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
         {
             CWalletTx* pcoin = &(*it).second;
-            if (!pcoin->IsFinal() || pcoin->fSpent || !pcoin->IsConfirmed())
+            if (!pcoin->IsFinal() || !pcoin->IsConfirmed())
                 continue;
-            nTotal += pcoin->GetCredit();
+            nTotal += pcoin->GetAvailableCredit();
         }
     }
 
@@ -3763,14 +3759,17 @@ bool SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfTheirs, set<
 
        foreach(CWalletTx* pcoin, vCoins)
        {
-            if (!pcoin->IsFinal() || pcoin->fSpent || !pcoin->IsConfirmed())
+            if (!pcoin->IsFinal() || !pcoin->IsConfirmed())
+                continue;
+
+            if (pcoin->IsCoinBase() && pcoin->GetBlocksToMaturity() > 0)
                 continue;
 
             int nDepth = pcoin->GetDepthInMainChain();
             if (nDepth < (pcoin->IsFromMe() ? nConfMine : nConfTheirs))
                 continue;
 
-            int64 n = pcoin->GetCredit();
+            int64 n = pcoin->GetAvailableCredit();
             if (n <= 0)
                 continue;
             if (n == nTargetValue)
@@ -4017,12 +4016,11 @@ bool CommitTransaction(CWalletTx& wtxNew, CReserveKey& reservekey)
             // Mark old coins as spent
             set<CWalletTx*> setCoins;
             foreach(const CTxIn& txin, wtxNew.vin)
-                setCoins.insert(&mapWallet[txin.prevout.hash]);
-            foreach(CWalletTx* pcoin, setCoins)
             {
-                pcoin->fSpent = true;
-                pcoin->WriteToDisk();
-                vWalletUpdated.push_back(pcoin->GetHash());
+                CWalletTx &pcoin = mapWallet[txin.prevout.hash];
+                pcoin.MarkSpent(txin.prevout.n);
+                pcoin.WriteToDisk();
+                vWalletUpdated.push_back(pcoin.GetHash());
             }
         }
 
diff --git a/main.h b/main.h
index e9d0c00310..0711d4ba0a 100644
--- a/main.h
+++ b/main.h
@@ -738,6 +738,7 @@ public:
         fMerkleVerified = false;
     }
 
+
     IMPLEMENT_SERIALIZE
     (
         nSerSize += SerReadWrite(s, *(CTransaction*)this, nType, nVersion, ser_action);
@@ -774,15 +775,17 @@ public:
     unsigned int fTimeReceivedIsTxTime;
     unsigned int nTimeReceived;  // time received by this node
     char fFromMe;
-    char fSpent;
     string strFromAccount;
+    vector<char> vfSpent;
 
     // memory only
     mutable char fDebitCached;
     mutable char fCreditCached;
+    mutable char fAvailableCreditCached;
     mutable char fChangeCached;
     mutable int64 nDebitCached;
     mutable int64 nCreditCached;
+    mutable int64 nAvailableCreditCached;
     mutable int64 nChangeCached;
 
     // memory only UI hints
@@ -814,13 +817,15 @@ public:
         fTimeReceivedIsTxTime = false;
         nTimeReceived = 0;
         fFromMe = false;
-        fSpent = false;
         strFromAccount.clear();
+        vfSpent.clear();
         fDebitCached = false;
         fCreditCached = false;
+        fAvailableCreditCached = false;
         fChangeCached = false;
         nDebitCached = 0;
         nCreditCached = 0;
+        nAvailableCreditCached = 0;
         nChangeCached = 0;
         nTimeDisplayed = 0;
         nLinesDisplayed = 0;
@@ -832,22 +837,96 @@ public:
         CWalletTx* pthis = const_cast<CWalletTx*>(this);
         if (fRead)
             pthis->Init();
-        nSerSize += SerReadWrite(s, *(CMerkleTx*)this, nType, nVersion, ser_action);
-        READWRITE(vtxPrev);
+        char fSpent = false;
 
-        pthis->mapValue["fromaccount"] = pthis->strFromAccount;
-        READWRITE(mapValue);
-        pthis->strFromAccount = pthis->mapValue["fromaccount"];
-        pthis->mapValue.erase("fromaccount");
-        pthis->mapValue.erase("version");
+        if (!fRead)
+        {
+            pthis->mapValue["fromaccount"] = pthis->strFromAccount;
+
+            string str;
+            foreach(char f, vfSpent)
+            {
+                str += (f ? '1' : '0');
+                if (f)
+                    fSpent = true;
+            }
+            pthis->mapValue["spent"] = str;
+        }
 
+        nSerSize += SerReadWrite(s, *(CMerkleTx*)this, nType, nVersion,ser_action);
+        READWRITE(vtxPrev);
+        READWRITE(mapValue);
         READWRITE(vOrderForm);
         READWRITE(fTimeReceivedIsTxTime);
         READWRITE(nTimeReceived);
         READWRITE(fFromMe);
         READWRITE(fSpent);
+
+        if (fRead)
+        {
+            pthis->strFromAccount = pthis->mapValue["fromaccount"];
+
+            if (mapValue.count("spent"))
+                foreach(char c, pthis->mapValue["spent"])
+                    pthis->vfSpent.push_back(c != '0');
+            else
+                pthis->vfSpent.assign(vout.size(), fSpent);
+        }
+
+        pthis->mapValue.erase("fromaccount");
+        pthis->mapValue.erase("version");
+        pthis->mapValue.erase("spent");
     )
 
+    // marks certain txout's as spent
+    // returns true if any update took place
+    bool UpdateSpent(const vector<char>& vfNewSpent)
+    {
+        bool fReturn = false;
+        for (int i=0; i < vfNewSpent.size(); i++)
+        {
+            if (i == vfSpent.size())
+                break;
+
+            if (vfNewSpent[i] && !vfSpent[i])
+            {
+                vfSpent[i] = true;
+                fReturn = true;
+                fAvailableCreditCached = false;
+            }
+        }
+        return fReturn;
+    }
+
+    void MarkDirty()
+    {
+        fCreditCached = false;
+        fAvailableCreditCached = false;
+        fDebitCached = false;
+        fChangeCached = false;
+    }
+
+    void MarkSpent(unsigned int nOut)
+    {
+        if (nOut >= vout.size())
+            throw runtime_error("CWalletTx::MarkSpent() : nOut out of range");
+        vfSpent.resize(vout.size());
+        if (!vfSpent[nOut])
+        {
+            vfSpent[nOut] = true;
+            fAvailableCreditCached = false;
+        }
+    }
+
+    bool IsSpent(unsigned int nOut) const
+    {
+        if (nOut >= vout.size())
+            throw runtime_error("CWalletTx::IsSpent() : nOut out of range");
+        if (nOut >= vfSpent.size())
+            return false;
+        return (!!vfSpent[nOut]);
+    }
+
     int64 GetDebit() const
     {
         if (vin.empty())
@@ -873,6 +952,33 @@ public:
         return nCreditCached;
     }
 
+    int64 GetAvailableCredit(bool fUseCache=true) const
+    {
+        // Must wait until coinbase is safely deep enough in the chain before valuing it
+        if (IsCoinBase() && GetBlocksToMaturity() > 0)
+            return 0;
+
+        if (fUseCache && fAvailableCreditCached)
+            return nAvailableCreditCached;
+
+        int64 nCredit = 0;
+        for (int i = 0; i < vout.size(); i++)
+        {
+            if (!IsSpent(i))
+            {
+                const CTxOut &txout = vout[i];
+                nCredit += txout.GetCredit();
+                if (!MoneyRange(nCredit))
+                    throw runtime_error("CWalletTx::GetAvailableCredit() : value out of range");
+            }
+        }
+
+        nAvailableCreditCached = nCredit;
+        fAvailableCreditCached = true;
+        return nCredit;
+    }
+
+
     int64 GetChange() const
     {
         if (fChangeCached)