// ThreadManager.h
// 
// Revision Log
//
// Date       Who SAR     Notes
// ========== === ======= =====================================
// 2000-12-21 mph         Initial coding by Mark Henri of
//                        MPH Software - markhenri@attbi.com
// 2001-10-18 mph         revamp all the logic; make dynamic types
// 2001-10-26 mph         Change again; create global logic
// 
// A good place to put a loop for ensuring the completion of all
// threads is right after the message loop just before program 
// exit.  Beware of trying to second guess your program's message
// logic; especially with MDI apps.
//
// note: once you've put this into a project, find all occurances
//       of CThreadTracker in the code and make sure that none of
//       the thread type numbers you've assigned is duplicated or
//       out of range.
//
#ifdef SAMPLE_CODE
void myThread(void*) {
   CThreadTracker tt(0 /* thread type */); // defaults to 0
   // more code here
}

   // putting this after the message loop could save your life--
   // blocks until all threads are finished.
   if (! g_threadManager.WaitForThreadsToTerminate())
      throw WinException("still waiting on active threads to terminate", 
         __FILE__, __LINE__);

#endif

#ifndef ACTIVETHREADCOUNT_H__
#define ACTIVETHREADCOUNT_H__

#include "CriticalSection.h"

#if _MSC_VER >= 1000
#pragma once
#endif // _MSC_VER >= 1000

class CThreadManager
{
public:
   CThreadManager();
   virtual ~CThreadManager();
   friend class CThreadTracker;

   void SetTypes(int numberOfTypes); // reallocation resets all counts
   int GetTypes() { return types; }
   int GetActiveThreads(int type=-1); // -1 == all
   bool WaitForThreadsToTerminate(int SecondsMax=60); // one minute default

private:
   CThreadManager(CThreadManager&); // not allowed
   operator=(CThreadManager&); // also, not allowed

   int Increment(int threadType=0);
   int Decrement(int threadType=0);
   void InitializeCounts();

   virtual void Changed() {;} // override with specialized "callback" behavior

   CCriticalSection criticalSection;
   int* active;
   int types;
};

#ifdef IN_THREADMANAGER_CPP
CThreadManager g_threadManager; // global variable
#else
extern CThreadManager g_threadManager;
#endif

class CThreadTracker
{
public:
   CThreadTracker(int threadType=0) { g_threadManager.Increment(_threadType = threadType); }
   ~CThreadTracker() { g_threadManager.Decrement(_threadType); }
protected:
private:
   CThreadTracker(CThreadTracker&); // not allowed
   operator=(CThreadTracker&); // also not allowed
   int _threadType;
};

#endif