Shutdown cleanup prep-work

Create a boost::thread_group object at the qt/bitcoind main-loop level
that will hold pointers to all the main-loop threads.

This will replace the vnThreadsRunning[] array.

For testing, ported the BitcoinMiner threads to use its
own boost::thread_group.

src/main.cpp

@@ -61,8 +61,8 @@ CScript COINBASE_FLAGS;
 
 const string strMessageMagic = "Bitcoin Signed Message:\n";
 
-double dHashesPerSec;
-int64 nHPSTimerStart;
+double dHashesPerSec = 0.0;
+int64 nHPSTimerStart = 0;
 
 // Settings
 int64 nTransactionFee = 0;
@@ -4089,6 +4089,8 @@ unsigned int static ScanHash_CryptoPP(char* pmidstate, char* pdata, char* phash1
             nHashesDone = 0xffff+1;
             return (unsigned int) -1;
         }
+        if ((nNonce & 0xfff) == 0)
+            boost::this_thread::interruption_point();
     }
 }
 
@@ -4506,37 +4508,19 @@ bool CheckWork(CBlock* pblock, CWallet& wallet, CReserveKey& reservekey)
     return true;
 }
 
-void static ThreadBitcoinMiner(void* parg);
-
-static bool fGenerateBitcoins = false;
-static bool fLimitProcessors = false;
-static int nLimitProcessors = -1;
-
 void static BitcoinMiner(CWallet *pwallet)
 {
     printf("BitcoinMiner started\n");
     SetThreadPriority(THREAD_PRIORITY_LOWEST);
-
-    // Make this thread recognisable as the mining thread
     RenameThread("bitcoin-miner");
 
     // Each thread has its own key and counter
     CReserveKey reservekey(pwallet);
     unsigned int nExtraNonce = 0;
 
-    while (fGenerateBitcoins)
-    {
-        if (fShutdown)
-            return;
-        while (vNodes.empty() || IsInitialBlockDownload())
-        {
+    try { loop {
+        while (vNodes.empty())
             Sleep(1000);
-            if (fShutdown)
-                return;
-            if (!fGenerateBitcoins)
-                return;
-        }
-
 
         //
         // Create new block
@@ -4553,7 +4537,6 @@ void static BitcoinMiner(CWallet *pwallet)
         printf("Running BitcoinMiner with %"PRIszu" transactions in block (%u bytes)\n", pblock->vtx.size(),
                ::GetSerializeSize(*pblock, SER_NETWORK, PROTOCOL_VERSION));
 
-
         //
         // Pre-build hash buffers
         //
@@ -4626,19 +4609,14 @@ void static BitcoinMiner(CWallet *pwallet)
                         if (GetTime() - nLogTime > 30 * 60)
                         {
                             nLogTime = GetTime();
-                            printf("hashmeter %3d CPUs %6.0f khash/s\n", vnThreadsRunning[THREAD_MINER], dHashesPerSec/1000.0);
+                            printf("hashmeter %6.0f khash/s\n", dHashesPerSec/1000.0);
                         }
                     }
                 }
             }
 
             // Check for stop or if block needs to be rebuilt
-            if (fShutdown)
-                return;
-            if (!fGenerateBitcoins)
-                return;
-            if (fLimitProcessors && vnThreadsRunning[THREAD_MINER] > nLimitProcessors)
-                return;
+            boost::this_thread::interruption_point();
             if (vNodes.empty())
                 break;
             if (nBlockNonce >= 0xffff0000)
@@ -4658,57 +4636,35 @@ void static BitcoinMiner(CWallet *pwallet)
                 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
             }
         }
-    }
-}
-
-void static ThreadBitcoinMiner(void* parg)
-{
-    CWallet* pwallet = (CWallet*)parg;
-    try
+    } }
+    catch (boost::thread_interrupted)
     {
-        vnThreadsRunning[THREAD_MINER]++;
-        BitcoinMiner(pwallet);
-        vnThreadsRunning[THREAD_MINER]--;
+        printf("BitcoinMiner terminated\n");
+        throw;
     }
-    catch (std::exception& e) {
-        vnThreadsRunning[THREAD_MINER]--;
-        PrintException(&e, "ThreadBitcoinMiner()");
-    } catch (...) {
-        vnThreadsRunning[THREAD_MINER]--;
-        PrintException(NULL, "ThreadBitcoinMiner()");
-    }
-    nHPSTimerStart = 0;
-    if (vnThreadsRunning[THREAD_MINER] == 0)
-        dHashesPerSec = 0;
-    printf("ThreadBitcoinMiner exiting, %d threads remaining\n", vnThreadsRunning[THREAD_MINER]);
 }
 
-
 void GenerateBitcoins(bool fGenerate, CWallet* pwallet)
 {
-    fGenerateBitcoins = fGenerate;
-    nLimitProcessors = GetArg("-genproclimit", -1);
-    if (nLimitProcessors == 0)
-        fGenerateBitcoins = false;
-    fLimitProcessors = (nLimitProcessors != -1);
+    static boost::thread_group* minerThreads = NULL;
 
-    if (fGenerate)
+    int nThreads = GetArg("-genproclimit", -1);
+    if (nThreads < 0)
+        nThreads = boost::thread::hardware_concurrency();
+
+    if (minerThreads != NULL)
     {
-        int nProcessors = boost::thread::hardware_concurrency();
-        printf("%d processors\n", nProcessors);
-        if (nProcessors < 1)
-            nProcessors = 1;
-        if (fLimitProcessors && nProcessors > nLimitProcessors)
-            nProcessors = nLimitProcessors;
-        int nAddThreads = nProcessors - vnThreadsRunning[THREAD_MINER];
-        printf("Starting %d BitcoinMiner threads\n", nAddThreads);
-        for (int i = 0; i < nAddThreads; i++)
-        {
-            if (!NewThread(ThreadBitcoinMiner, pwallet))
-                printf("Error: NewThread(ThreadBitcoinMiner) failed\n");
-            Sleep(10);
-        }
+        minerThreads->interrupt_all();
+        delete minerThreads;
+        minerThreads = NULL;
     }
+
+    if (nThreads == 0 || !fGenerate)
+        return;
+
+    minerThreads = new boost::thread_group();
+    for (int i = 0; i < nThreads; i++)
+        minerThreads->create_thread(boost::bind(&BitcoinMiner, pwallet));
 }
 
 // Amount compression: