OutputFile.hh

//
// This file is part of MARLEY (Model of Argon Reaction Low Energy Yields)
//
// MARLEY is free software: you can redistribute it and/or modify it under the
// terms of version 3 of the GNU General Public License as published by the
// Free Software Foundation.
//
// For the full text of the license please see COPYING or
// visit http://opensource.org/licenses/GPL-3.0
//
// Please respect the MCnet academic usage guidelines. See GUIDELINES
// or visit https://www.montecarlonet.org/GUIDELINES for details.
 
#pragma once
 
// standard library includes
#include <fstream>
#include <memory>
#include <string>
 
namespace HepMC3 {
  class GenRunInfo;
}
 
namespace marley {
 
  class Generator;
  class JSON;

  class OutputFile {
 
    protected:
 
      // The input JSON object typically appears under the "output" key in the
      // "generate" section of a MARLEY job configuration file
      OutputFile( const JSON& output_config );
 
    public:
 
      // Factory method that constructs an appropriate derived object given the
      // input JSON configuration
      static std::shared_ptr< OutputFile > make_OutputFile(
        const JSON& output_config );
 
      virtual ~OutputFile() = default;
 
      const std::string& name() const { return name_; }

      virtual bool resume( std::unique_ptr<marley::Generator>& gen,
        long& num_previous_events ) = 0;

      virtual int_fast64_t bytes_written() = 0;

      virtual void write_event( HepMC3::GenEvent* event ) = 0;
 
      bool mode_is_resume() const { return mode_ == Mode::RESUME; }
 
      // Add more formats to the enum class as needed. This should include
      // every event format that MARLEY knows how to write. The "ASCII" format
      // is MARLEY's native format for textual input and output of
      // HepMC3::GenEvent objects.
      enum class Format { ASCII, ROOT };
 
    protected:

      inline bool check_if_file_exists( const std::string& filename ) {
        std::ifstream test_stream( filename );
        return test_stream.good();
      }

      void prompt_before_overwrite();

      std::unique_ptr< marley::Generator > restore_generator(
        const marley::JSON& config );

      static void merge_reweight_provenance_weights(
        HepMC3::GenRunInfo& run_info, marley::Generator& gen );
 
      // Modes to use when writing output to files that are not initially empty
      // OVERWRITE = removes any previous contents of the file, then writes new
      //   events in the requested format.
      // RESUME = uses saved metadata in a file to restore a previous MARLEY
      //   configuration (including the random number generator state), then
      //   appends new events after those currently saved in the file.
      enum class Mode { OVERWRITE, RESUME };
 
      std::string name_; 
      Format format_; 
      Mode mode_;
 
      // Whether to force the current output mode without prompting the user.
      // Currently only used when setting the OVERWRITE output mode.
      bool force_;
  };
 
}