CallNTimesNoWait.h

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#ifndef FWCore_Utilities_CallNTimesNoWait_h
#define FWCore_Utilities_CallNTimesNoWait_h
// -*- C++ -*-
//
// Package:     FWCore/Utilities
// Class  :     CallNTimesNoWait
//
//
// Original Author:  Chris Jones
//         Created:  Fri, 15 Nov 2013 14:29:41 GMT
//

// system include files
#include <atomic>

// user include files

// forward declarations
namespace edm {
  class CallNTimesNoWait {
  public:
    CallNTimesNoWait(unsigned short iNTimes) : m_ntimes(static_cast<int>(iNTimes) - 1), m_done(false) {}

    template <typename T>
    void operator()(T iCall) {
      if (not m_done.load(std::memory_order_acquire)) {
        if (m_ntimes.fetch_sub(1, std::memory_order_acq_rel) < 0) {
          m_done.store(true, std::memory_order_release);
          return;
        };
        iCall();
      }
    }

  private:
    std::atomic<int> m_ntimes;
    std::atomic<bool> m_done;
  };
}  // namespace edm

#endif