Regression test for ResendWalletTransactions

Adds a regression test for the wallet's ResendWalletTransactions function, which uses a new, hidden RPC command "resendwallettransactions."

I refactored main's Broadcast signal so it is passed the best-block time, which let me remove a global variable shared between main.cpp and the wallet (nTimeBestReceived).

I also manually tested the "rebroadcast unconfirmed every half hour or so" functionality by:

1. Running bitcoind -connect=0.0.0.0:8333
2. Creating a couple of send-to-self transactions
3. Connect to a peer using -addnode
4. Waited a while, monitoring debug.log, until I see:
```2015-03-23 18:48:10 ResendWalletTransactions: rebroadcast 2 unconfirmed transactions```

One last change: don't bother putting ResendWalletTransactions messages in debug.log unless unconfirmed transactions were actually rebroadcast.

3 files changed, 59 insertions, 25 deletions

diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 9318c1b2b1..29f3eda15d 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -2096,3 +2096,25 @@ Value getwalletinfo(const Array& params, bool fHelp)
         obj.push_back(Pair("unlocked_until", nWalletUnlockTime));
     return obj;
 }
+
+Value resendwallettransactions(const Array& params, bool fHelp)
+{
+    if (fHelp || params.size() != 0)
+        throw runtime_error(
+            "resendwallettransactions\n"
+            "Immediately re-broadcast unconfirmed wallet transactions to all peers.\n"
+            "Intended only for testing; the wallet code periodically re-broadcasts\n"
+            "automatically.\n"
+            "Returns array of transaction ids that were re-broadcast.\n"
+            );
+
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
+    std::vector<uint256> txids = pwalletMain->ResendWalletTransactionsBefore(GetTime());
+    Array result;
+    BOOST_FOREACH(const uint256& txid, txids)
+    {
+        result.push_back(txid.ToString());
+    }
+    return result;
+}
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 09bcda577e..a10123002e 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1114,15 +1114,17 @@ void CWallet::ReacceptWalletTransactions()
     }
 }
 
-void CWalletTx::RelayWalletTransaction()
+bool CWalletTx::RelayWalletTransaction()
 {
     if (!IsCoinBase())
     {
         if (GetDepthInMainChain() == 0) {
             LogPrintf("Relaying wtx %s\n", GetHash().ToString());
             RelayTransaction((CTransaction)*this);
+            return true;
         }
     }
+    return false;
 }
 
 set<uint256> CWalletTx::GetConflicts() const
@@ -1324,7 +1326,31 @@ bool CWalletTx::IsTrusted() const
     return true;
 }
 
-void CWallet::ResendWalletTransactions()
+std::vector<uint256> CWallet::ResendWalletTransactionsBefore(int64_t nTime)
+{
+    std::vector<uint256> result;
+
+    LOCK(cs_wallet);
+    // Sort them in chronological order
+    multimap<unsigned int, CWalletTx*> mapSorted;
+    BOOST_FOREACH(PAIRTYPE(const uint256, CWalletTx)& item, mapWallet)
+    {
+        CWalletTx& wtx = item.second;
+        // Don't rebroadcast if newer than nTime:
+        if (wtx.nTimeReceived > nTime)
+            continue;
+        mapSorted.insert(make_pair(wtx.nTimeReceived, &wtx));
+    }
+    BOOST_FOREACH(PAIRTYPE(const unsigned int, CWalletTx*)& item, mapSorted)
+    {
+        CWalletTx& wtx = *item.second;
+        if (wtx.RelayWalletTransaction())
+            result.push_back(wtx.GetHash());
+    }
+    return result;
+}
+
+void CWallet::ResendWalletTransactions(int64_t nBestBlockTime)
 {
     // Do this infrequently and randomly to avoid giving away
     // that these are our transactions.
@@ -1336,30 +1362,15 @@ void CWallet::ResendWalletTransactions()
         return;
 
     // Only do it if there's been a new block since last time
-    if (nTimeBestReceived < nLastResend)
+    if (nBestBlockTime < nLastResend)
         return;
     nLastResend = GetTime();
 
-    // Rebroadcast any of our txes that aren't in a block yet
-    LogPrintf("ResendWalletTransactions()\n");
-    {
-        LOCK(cs_wallet);
-        // Sort them in chronological order
-        multimap<unsigned int, CWalletTx*> mapSorted;
-        BOOST_FOREACH(PAIRTYPE(const uint256, CWalletTx)& item, mapWallet)
-        {
-            CWalletTx& wtx = item.second;
-            // Don't rebroadcast until it's had plenty of time that
-            // it should have gotten in already by now.
-            if (nTimeBestReceived - (int64_t)wtx.nTimeReceived > 5 * 60)
-                mapSorted.insert(make_pair(wtx.nTimeReceived, &wtx));
-        }
-        BOOST_FOREACH(PAIRTYPE(const unsigned int, CWalletTx*)& item, mapSorted)
-        {
-            CWalletTx& wtx = *item.second;
-            wtx.RelayWalletTransaction();
-        }
-    }
+    // Rebroadcast unconfirmed txes older than 5 minutes before the last
+    // block was found:
+    std::vector<uint256> relayed = ResendWalletTransactionsBefore(nBestBlockTime-5*60);
+    if (!relayed.empty())
+        LogPrintf("%s: rebroadcast %u unconfirmed transactions\n", __func__, relayed.size());
 }
 
 /** @} */ // end of mapWallet
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 4a13f02195..6ae1c87b1d 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -381,7 +381,7 @@ public:
     int64_t GetTxTime() const;
     int GetRequestCount() const;
 
-    void RelayWalletTransaction();
+    bool RelayWalletTransaction();
 
     std::set<uint256> GetConflicts() const;
 };
@@ -614,7 +614,8 @@ public:
     void EraseFromWallet(const uint256 &hash);
     int ScanForWalletTransactions(CBlockIndex* pindexStart, bool fUpdate = false);
     void ReacceptWalletTransactions();
-    void ResendWalletTransactions();
+    void ResendWalletTransactions(int64_t nBestBlockTime);
+    std::vector<uint256> ResendWalletTransactionsBefore(int64_t nTime);
     CAmount GetBalance() const;
     CAmount GetUnconfirmedBalance() const;
     CAmount GetImmatureBalance() const;