ProgressMeter.h

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// ========================================================================= //
// This file is part of MyraMath, copyright (c) 2014-2019 by Ryan A Chilton  //
// and distributed by MyraCore, LLC. See LICENSE.txt for license terms.      //
// ========================================================================= //

#ifndef MYRAMATH_JOBGRAPH_PROGRESSMETER_H
#define MYRAMATH_JOBGRAPH_PROGRESSMETER_H

#include <stdint.h>
#include <string>
#include <myramath/utility/detail/LIBPUBLIC.h>

namespace myra {

// Forward declarations.
class ProgressMeterBase;
class ProgressMeter;

class LIBPUBLIC ProgressMeterBase
  {
  public:
  
    virtual ~ProgressMeterBase();

  protected:

    // Called when a lengthy calculation is started.
    virtual void begin(const std::string& name, uint64_t total) = 0;

    // Called repeatedly between begin() and end(), to regularly increment progress.
    virtual void increment(uint64_t delta) = 0;

    // Called when a lengthy calculation is finished.
    virtual void end() = 0;

    // Regularly polled while a JobGraph execute()'s, execution will halt if kill()==true.
    virtual bool kill() = 0;

    // Virtual copy constructor.
    virtual ProgressMeterBase* clone() const = 0;

    // Friendship for encapsulating ProgressMeter, to it can clone()/copy.
    friend class ::myra::ProgressMeter;
    
  };

class LIBPUBLIC ProgressMeter
  {
  public:

    // ------------------------------------ Value semantics.

    ProgressMeter();

    ProgressMeter(const ProgressMeterBase& that);

    ProgressMeter(const ProgressMeter& that);

    void swap(ProgressMeter& that);

    ProgressMeter& operator= (ProgressMeter that);

   ~ProgressMeter();

    // ------------------------------------ ProgressMeter API.

    //    name  = something human-readable that describes the operation
    //    total = how much "work" is required to complete the operation (e.g. #flops)
    void begin(const std::string& name, uint64_t total);

    //    delta = how much "work" has been completed, sum of all deltas eventually adds up to total
    void increment(uint64_t delta);

    void end();

    bool kill();

  private:
  
    // Underlying polymorphic instance, a ProgressMeterBase.
    ProgressMeterBase* base;

    // A "latch" bit for kill().
    bool kill_latch;
    
  };

} // namespace myra

#endif