Fixed a really dumb bug in threadpool that would leave no threads

left to process jobs.  Also added an accessor to see how big
the job queue is.

src/ThreadPool.cpp

@@ -13,6 +13,7 @@ ThreadPool::ThreadPool() : maxThreads(1000), die(false), threadsWaiting(0)
     // context it's used in.  In the CRP class for example, the # of active threads would be 
     // naturally limited by the # of concurrent operations.
     logger = SMLogging::get();
+    pruner = boost::thread([this] { this->prune(); } );
 }
 
 ThreadPool::ThreadPool(uint num_threads, bool _processQueueOnExit) : maxThreads(num_threads), die(false), 
@@ -62,8 +63,9 @@ void ThreadPool::prune()
     {
         while (pruneable.empty() && !die)
             somethingToPrune.wait(s);
+            
         if (die)
-            return;
+            break;
         
         for (auto &id : pruneable)
         {
@@ -83,6 +85,12 @@ void ThreadPool::setMaxThreads(uint newMax)
     maxThreads = newMax;
 }
 
+int ThreadPool::currentQueueSize() const
+{
+    boost::unique_lock<boost::mutex> s(mutex);
+    return jobs.size();
+}
+
 void ThreadPool::processingLoop()
 {
     try

src/ThreadPool.h

@@ -27,6 +27,7 @@ class ThreadPool : public boost::noncopyable
         
         void addJob(const boost::shared_ptr<Job> &j);
         void setMaxThreads(uint newMax);
+        int currentQueueSize() const;
 
     private:
         void processingLoop();   // the fcn run by each thread
@@ -57,7 +58,7 @@ class ThreadPool : public boost::noncopyable
         
         boost::condition jobAvailable;
         std::deque<boost::shared_ptr<Job> > jobs;
-        boost::mutex mutex;
+        mutable boost::mutex mutex;
         
         const boost::posix_time::time_duration idleThreadTimeout = boost::posix_time::seconds(60);
         boost::thread pruner;