DelayedReader.h

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#ifndef FWCore_Framework_DelayedReader_h
#define FWCore_Framework_DelayedReader_h
 
/*----------------------------------------------------------------------
 
DelayedReader: The abstract interface through which the Principal
uses input sources to retrieve EDProducts from external storage.
 
----------------------------------------------------------------------*/
 
#include "DataFormats/Common/interface/WrapperBase.h"
 
#include <memory>
#include <mutex>
 
namespace edm {
 
  class BranchID;
  class EDProductGetter;
  class ModuleCallingContext;
  class SharedResourcesAcquirer;
  class StreamContext;
 
  namespace signalslot {
    template <typename T>
    class Signal;
  }
 
  class DelayedReader {
  public:
    virtual ~DelayedReader();
    std::unique_ptr<WrapperBase> getProduct(BranchID const& k,
                                            EDProductGetter const* ep,
                                            ModuleCallingContext const* mcc = nullptr);
 
    void mergeReaders(DelayedReader* other) { mergeReaders_(other); }
    void reset() { reset_(); }
 
    std::pair<SharedResourcesAcquirer*, std::recursive_mutex*> sharedResources() const { return sharedResources_(); }
 
    virtual signalslot::Signal<void(StreamContext const&, ModuleCallingContext const&)> const*
    preEventReadFromSourceSignal() const = 0;
    virtual signalslot::Signal<void(StreamContext const&, ModuleCallingContext const&)> const*
    postEventReadFromSourceSignal() const = 0;
 
  private:
    virtual std::unique_ptr<WrapperBase> getProduct_(BranchID const& k, EDProductGetter const* ep) = 0;
    virtual void mergeReaders_(DelayedReader*) = 0;
    virtual void reset_() = 0;
    virtual std::pair<SharedResourcesAcquirer*, std::recursive_mutex*> sharedResources_() const;
  };
}  // namespace edm
 
#endif