DAGScheduler.h

#ifndef DAGSCHEDULER_H
#define DAGSCHEDULER_H

#include <set>
#include <utility>
#include <vector>
#include <map>

/// The high-performance DAG scheduler. Visits the DAG obeying the dependencies.
///
///   @author Mario Valle - Swiss National Supercomputing Centre (CSCS)
///   @date 2012-05-14 (initial version)
///   @version 1.1
///
class DAGScheduler {
public:
  /// Constructor.
  ///
  DAGScheduler() {}

  /// Destructor.
  ///
  ~DAGScheduler() {}

  /// Clean everything
  ///
  void clear(void);

  /// Add a piece of DAG
  ///
  /// @param[in] aCopyId The current copy of the forest in which the dependency
  /// should be recorded
  /// @param[in] aDependsOn The object on which aDependant depends
  /// @param[in] aDependant The object to be computed only when aDependsOn is
  /// ready
  ///
  void loadDependency(unsigned int aCopyId, const void *aDependsOn,
                      const void *aDependant);

  /// Signals dependencies load has finished.
  ///
  /// @param[in] aNumCodonSets Number of DAG copies (one for each codon classes)
  ///
  void endLoadDependencies(unsigned int aNumCodonSets = 1);

  /// Get next item to process.
  ///
  /// @return The next object with all dependencies satisfied. Return NULL if no
  /// more objects to be executed.
  ///
  void *getNext(void);

  /// Signals finished execution on aItem.
  ///
  /// @param[in] aItem Object on which execution has ended.
  ///
  void setDone(const void *aItem);

  /// Reset all dependencies to initial state
  ///
  void resetDependencies(void);

  /// Dump DAG in textual form
  ///
  void dumpDAG(std::ostream &aOut) const;

private:
  std::set<const void *> mNodes; ///< Load the distinct node addresses
  std::vector<std::pair<const void *, const void *> >
      mEdges;                              ///< Load the edges
  std::map<const void *, int> mRefCounter; ///< Reference counter
  std::map<const void *, int>
      mRefCounterSave; ///< Save the reference counter map
};

#endif