PluginFactoryBase.h

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#ifndef FWCore_PluginManager_PluginFactoryBase_h
#define FWCore_PluginManager_PluginFactoryBase_h
// -*- C++ -*-
//
// Package:     PluginManager
// Class  :     PluginFactoryBase
// 
//
// Original Author:  Chris Jones
//         Created:  Wed Apr  4 12:24:44 EDT 2007
//

// system include files
#include <string>
#include <vector>
#include <map>
#include <atomic>
#include "tbb/concurrent_unordered_map.h"
#include "tbb/concurrent_vector.h"

#include "FWCore/Utilities/interface/Signal.h"
// user include files
#include "FWCore/PluginManager/interface/PluginInfo.h"

// forward declarations
namespace edmplugin {
class PluginFactoryBase
{

   public:
      PluginFactoryBase() {}
      virtual ~PluginFactoryBase();

      struct PluginMakerInfo {
        PluginMakerInfo(void* iPtr, const std::string& iName):
        m_name(iName),
        m_ptr() {
          m_ptr.store(iPtr,std::memory_order_release);}
        
        PluginMakerInfo(const PluginMakerInfo& iOther):
        m_name(iOther.m_name),
        m_ptr() {
          m_ptr.store(iOther.m_ptr.load(std::memory_order_acquire),
                      std::memory_order_release);
        }
        
        PluginMakerInfo& operator=(const PluginMakerInfo& iOther) {
          m_name = iOther.m_name;
          m_ptr.store(iOther.m_ptr.load(std::memory_order_acquire),std::memory_order_release);
          return *this;
        }
        std::string m_name;
        //NOTE: this has to be last since once it is non zero it signals
        // that the construction has finished
        std::atomic<void*> m_ptr;
      };
  
      typedef tbb::concurrent_vector<PluginMakerInfo> PMakers;
      typedef tbb::concurrent_unordered_map<std::string, PMakers > Plugins;

      // ---------- const member functions ---------------------

      virtual std::vector<PluginInfo> available() const;

      virtual const std::string& category() const = 0;
      
      mutable edm::signalslot::Signal<void(const std::string&, const PluginInfo&)> newPluginAdded_;

      // ---------- static member functions --------------------

      // ---------- member functions ---------------------------

   protected:
      void finishedConstruction();
      
      void newPlugin(const std::string& iName);

      //since each inheriting class has its own Container type to hold their PMakers
      // this function allows them to share the same code when doing the lookup
      // this routine will throw an exception if iName is unknown therefore the return value is always valid
      void* findPMaker(const std::string& iName) const;

      //similar to findPMaker but will return 'end()' if iName is known
      void* tryToFindPMaker(const std::string& iName) const;
      
      void fillInfo(const PMakers &makers,
                    PluginInfo& iInfo,
                    std::vector<PluginInfo>& iReturn ) const;

      void fillAvailable(std::vector<PluginInfo>& iReturn) const;

      void registerPMaker(void* iPMaker, const std::string& iName);
      
   private:
      PluginFactoryBase(const PluginFactoryBase&) = delete; // stop default

      const PluginFactoryBase& operator=(const PluginFactoryBase&) = delete; // stop default

      void checkProperLoadable(const std::string& iName, const std::string& iLoadedFrom) const;
      // ---------- member data --------------------------------
      Plugins m_plugins;
  

};

}
#endif