From ddd0acd3dbbbf3e19d2379fc9b24e7ef5c2a8adb Mon Sep 17 00:00:00 2001
From: Gavin Andresen <gavinandresen@gmail.com>
Date: Fri, 3 Apr 2015 11:50:06 -0400
Subject: [PATCH] Create a scheduler thread for lightweight tasks

---
 src/bitcoind.cpp   | 4 +++-
 src/init.cpp       | 7 ++++++-
 src/init.h         | 3 ++-
 src/qt/bitcoin.cpp | 4 +++-
 4 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/bitcoind.cpp b/src/bitcoind.cpp
index eeca8655c98..cce687ac98c 100644
--- a/src/bitcoind.cpp
+++ b/src/bitcoind.cpp
@@ -8,6 +8,7 @@
 #include "init.h"
 #include "main.h"
 #include "noui.h"
+#include "scheduler.h"
 #include "util.h"
 
 #include <boost/algorithm/string/predicate.hpp>
@@ -55,6 +56,7 @@ void WaitForShutdown(boost::thread_group* threadGroup)
 bool AppInit(int argc, char* argv[])
 {
     boost::thread_group threadGroup;
+    CScheduler scheduler;
 
     bool fRet = false;
 
@@ -142,7 +144,7 @@ bool AppInit(int argc, char* argv[])
 #endif
         SoftSetBoolArg("-server", true);
 
-        fRet = AppInit2(threadGroup);
+        fRet = AppInit2(threadGroup, scheduler);
     }
     catch (const std::exception& e) {
         PrintExceptionContinue(&e, "AppInit()");
diff --git a/src/init.cpp b/src/init.cpp
index 47cbda32f5b..51f3671c1d2 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -19,6 +19,7 @@
 #include "net.h"
 #include "rpcserver.h"
 #include "script/standard.h"
+#include "scheduler.h"
 #include "txdb.h"
 #include "ui_interface.h"
 #include "util.h"
@@ -564,7 +565,7 @@ bool InitSanityCheck(void)
 /** Initialize bitcoin.
  *  @pre Parameters should be parsed and config file should be read.
  */
-bool AppInit2(boost::thread_group& threadGroup)
+bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
 {
     // ********************************************************* Step 1: setup
 #ifdef _MSC_VER
@@ -890,6 +891,10 @@ bool AppInit2(boost::thread_group& threadGroup)
             threadGroup.create_thread(&ThreadScriptCheck);
     }
 
+    // Start the lightweight task scheduler thread
+    CScheduler::Function serviceLoop = boost::bind(&CScheduler::serviceQueue, &scheduler);
+    threadGroup.create_thread(boost::bind(&TraceThread<CScheduler::Function>, "scheduler", serviceLoop));
+
     /* Start the RPC server already.  It will be started in "warmup" mode
      * and not really process calls already (but it will signify connections
      * that the server is there and will be ready later).  Warmup mode will
diff --git a/src/init.h b/src/init.h
index d451f65be93..dcb2b293608 100644
--- a/src/init.h
+++ b/src/init.h
@@ -8,6 +8,7 @@
 
 #include <string>
 
+class CScheduler;
 class CWallet;
 
 namespace boost
@@ -20,7 +21,7 @@ extern CWallet* pwalletMain;
 void StartShutdown();
 bool ShutdownRequested();
 void Shutdown();
-bool AppInit2(boost::thread_group& threadGroup);
+bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler);
 
 /** The help message mode determines what help message to show */
 enum HelpMessageMode {
diff --git a/src/qt/bitcoin.cpp b/src/qt/bitcoin.cpp
index 018169cfdc5..8740b98b70c 100644
--- a/src/qt/bitcoin.cpp
+++ b/src/qt/bitcoin.cpp
@@ -26,6 +26,7 @@
 #include "init.h"
 #include "main.h"
 #include "rpcserver.h"
+#include "scheduler.h"
 #include "ui_interface.h"
 #include "util.h"
 
@@ -178,6 +179,7 @@ signals:
 
 private:
     boost::thread_group threadGroup;
+    CScheduler scheduler;
 
     /// Pass fatal exception message to UI thread
     void handleRunawayException(const std::exception *e);
@@ -258,7 +260,7 @@ void BitcoinCore::initialize()
     try
     {
         qDebug() << __func__ << ": Running AppInit2 in thread";
-        int rv = AppInit2(threadGroup);
+        int rv = AppInit2(threadGroup, scheduler);
         if(rv)
         {
             /* Start a dummy RPC thread if no RPC thread is active yet