CleanupManager.h

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/*
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   The MIT License

   Copyright (c) 2009 Scientific Computing and Imaging Institute,
   University of Utah.

   
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/*
 *@file  CleanupManager.cc
 *@brief Manage exitAll callbacks.
 *
 *@author
 *   Michael Callahan
 *   Department of Computer Science
 *   University of Utah
 *@date  November 2004
 *
 */

/*
 *@details
 *  How to use this class:
 *  
 *  #include <Core/Thread/Legacy/Legacy/CleanupManager.h>
 *  
 *  Make a callback function that takes zero arguements and returns
 *  void.  Be very careful about introducing crashes into this
 *  callback function as it then becomes difficult to exit from
 *  scirun.  It's recommended that you avoid calling new from
 *  within your callback.
 *  
 *  Register with CleanupManager::add_callback(YOUR_CALLBACK_HERE, MISC_DATA);
 *  
 *  Your callback will only ever be called once, no matter how many
 *  times you register it.  In addition you can unregister it or
 *
 *  design it such that it doesn't do anything if it doesn't need to.
 *  Here is an example of how this could be used:
 */
//  class Myclass {
//  public:
//    Myclass() {
//      CleanupManager::add_callback(this->cleanup_wrap, this);
//    }
//  
//    ~Myclass() {
//      // Need to remove and call callback at same time or else you get
//      // a race condition and the callback could be called twice.
//      CleanupManger::invoke_remove_callback(this->cleanup_wrap, this);
//    }
//  
//  private: 
//    static void cleanup_wrap(void *ptr) {
//      ((Myclass *)ptr)->cleanup();
//    }
//  
//    void cleanup();
//  }
//  

#ifndef SCI_project_CleanupManager_h
#define SCI_project_CleanupManager_h 1

#include <Core/Thread/Legacy/Mutex.h>
#include <vector>

#include <Core/Thread/Legacy/share.h>

namespace SCIRun {

typedef void (*CleanupManagerCallback)(void *);

class SCISHARE CleanupManager {
public:
  
  // Initializes the mutex lock for the cleanup manager.  Initialize
  // is called from the Thread::initialize and is only called once.
  static void initialize();

  static void add_callback(CleanupManagerCallback cb, void *data);
  static void invoke_remove_callback(CleanupManagerCallback cb, void *data);
  static void remove_callback(CleanupManagerCallback cb, void *data);

  // After calling this, all registered functions will be removed.
  // Should this also delete all the memory allocated by initialize()?
  static void call_callbacks();

protected:
  // callbacks_ needs to be allocated off the heap to make sure it's
  // still around when exitAll is called.
  static std::vector<std::pair<CleanupManagerCallback, void *> >* callbacks_;
  static bool    initialized_;
  static Mutex * lock_;
};

} // End namespace SCIRun


#endif /* SCI_project_CleanupManager_h */