LambdaJobGraph.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_LAMBDAJOBGRAPH_H
#define MYRAMATH_JOBGRAPH_LAMBDAJOBGRAPH_H

#include <myramath/MYRAMATH_EXPORT.h>

#include <myramath/jobgraph/Job.h>
#include <myramath/jobgraph/JobID.h>
#include <myramath/jobgraph/JobGraph.h>

#include <string>
#include <stdint.h>

namespace myra {

template<class Lambda> class LambdaJobGraph : public JobGraphBase
  {
  private:

    class Job;
    friend class Job;
    Lambda lambda;
    std::string n;

  public:

    LambdaJobGraph(const Lambda& in_lambda)
      : lambda(in_lambda), n("LambdaJob") { }

    LambdaJobGraph(const Lambda& in_lambda, const std::string& in_n)
      : lambda(in_lambda), n(in_n) { }

    virtual JobGraphBase* clone() const
      { return new LambdaJobGraph<Lambda>(*this); }

    virtual ~LambdaJobGraph()
      { }

    // --------------------------- Base JobGraph overrides.

    virtual uint64_t n_work() const
      { return 1; }
    
    virtual std::string name() const
      { return n; }

    virtual void begins(JobIDs& output) const
      { output.push_back( JobID(0) ); }

    virtual void ends(JobIDs& output) const
      { output.push_back( JobID(0) ); }

    virtual Job* create(JobID j)
      { return new Job(this); }

    virtual std::vector<::myra::Job*> create()
      { return std::vector<::myra::Job*>(1,new Job(this)); }

    virtual uint64_t size() const
      { return 1; }

  private:

    // Implementation detail, calls the Lambda when execute()'d
    class Job : public ::myra::Job
      {
      private:
      
        // Host graph.
        LambdaJobGraph* host;
              
      public:

        // Constructor, requires underlying Job* j and host graph g.
        Job(LambdaJobGraph* in_host)
          : host(in_host) { }

        // Returns (0).
        virtual JobID id() const
          { return JobID(0); }

        // Empty set.
        virtual void parents(JobIDs& output) const
          { }

        // Empty set.
        virtual void children(JobIDs& output) const
          { }
        
        // Returns j->execute()
        virtual uint64_t execute()
          { host->lambda(); return 1; }

        // Returns j->name()
        virtual std::string name() const
          { return host->n; }

        // Deletes j.
        virtual ~Job()
          { }

      };
    
  };

template<class Lambda> 
JobGraph make_LambdaJobGraph(const Lambda& lambda)
  { return JobGraph(LambdaJobGraph<Lambda>(lambda)); }

template<class Lambda> 
JobGraph make_LambdaJobGraph(const Lambda& lambda, const std::string& name)
  { return JobGraph(LambdaJobGraph<Lambda>(lambda,name)); }

} // namespace myra

#endif