RFilter.hxx

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// Author: Enrico Guiraud, Danilo Piparo CERN  09/2018
 
/*************************************************************************
 * Copyright (C) 1995-2018, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#ifndef ROOT_RFILTER
#define ROOT_RFILTER
 
#include "ROOT/RDF/ColumnReaderUtils.hxx"
#include "ROOT/RDF/RColumnReaderBase.hxx"
#include "ROOT/RDF/RCutFlowReport.hxx"
#include "ROOT/RDF/Utils.hxx"
#include "ROOT/RDF/RFilterBase.hxx"
#include "ROOT/RDF/RLoopManager.hxx"
#include "ROOT/RIntegerSequence.hxx"
#include "ROOT/TypeTraits.hxx"
#include "RtypesCore.h"
 
#include <algorithm>
#include <memory>
#include <string>
#include <vector>
 
namespace ROOT {
 
namespace Internal {
namespace RDF {
using namespace ROOT::Detail::RDF;
 
// fwd decl for RFilter
namespace GraphDrawing {
std::shared_ptr<GraphNode> CreateFilterNode(const RFilterBase *filterPtr);
 
std::shared_ptr<GraphNode> AddDefinesToGraph(std::shared_ptr<GraphNode> node,
                                             const RDFInternal::RBookedDefines &defines,
                                             const std::vector<std::string> &prevNodeDefines);
} // ns GraphDrawing
 
} // ns RDF
} // ns Internal
 
namespace Detail {
namespace RDF {
using namespace ROOT::TypeTraits;
namespace RDFGraphDrawing = ROOT::Internal::RDF::GraphDrawing;
 
template <typename FilterF, typename PrevDataFrame>
class R__CLING_PTRCHECK(off) RFilter final : public RFilterBase {
   using ColumnTypes_t = typename CallableTraits<FilterF>::arg_types;
   using TypeInd_t = std::make_index_sequence<ColumnTypes_t::list_size>;
 
   FilterF fFilter;
   const ColumnNames_t fColumnNames;
   const std::shared_ptr<PrevDataFrame> fPrevDataPtr;
   PrevDataFrame &fPrevData;
   /// Column readers per slot and per input column
   std::vector<std::array<std::unique_ptr<RColumnReaderBase>, ColumnTypes_t::list_size>> fValues;
   /// The nth flag signals whether the nth input column is a custom column or not.
   std::array<bool, ColumnTypes_t::list_size> fIsDefine;
 
public:
   RFilter(FilterF f, const ColumnNames_t &columns, std::shared_ptr<PrevDataFrame> pd,
           const RDFInternal::RBookedDefines &defines, std::string_view name = "")
      : RFilterBase(pd->GetLoopManagerUnchecked(), name, pd->GetLoopManagerUnchecked()->GetNSlots(), defines),
        fFilter(std::move(f)), fColumnNames(columns), fPrevDataPtr(std::move(pd)), fPrevData(*fPrevDataPtr),
        fValues(fNSlots), fIsDefine()
   {
      const auto nColumns = fColumnNames.size();
      for (auto i = 0u; i < nColumns; ++i)
         fIsDefine[i] = fDefines.HasName(fColumnNames[i]);
   }
 
   RFilter(const RFilter &) = delete;
   RFilter &operator=(const RFilter &) = delete;
   // must call Deregister here, before fPrevDataFrame is destroyed,
   // otherwise if fPrevDataFrame is fLoopManager we get a use after delete
   ~RFilter() { fLoopManager->Deregister(this); }
 
   bool CheckFilters(unsigned int slot, Long64_t entry) final
   {
      if (entry != fLastCheckedEntry[slot * RDFInternal::CacheLineStep<Long64_t>()]) {
         if (!fPrevData.CheckFilters(slot, entry)) {
            // a filter upstream returned false, cache the result
            fLastResult[slot * RDFInternal::CacheLineStep<int>()] = false;
         } else {
            // evaluate this filter, cache the result
            auto passed = CheckFilterHelper(slot, entry, ColumnTypes_t{}, TypeInd_t{});
            passed ? ++fAccepted[slot * RDFInternal::CacheLineStep<ULong64_t>()]
                   : ++fRejected[slot * RDFInternal::CacheLineStep<ULong64_t>()];
            fLastResult[slot * RDFInternal::CacheLineStep<int>()] = passed;
         }
         fLastCheckedEntry[slot * RDFInternal::CacheLineStep<Long64_t>()] = entry;
      }
      return fLastResult[slot * RDFInternal::CacheLineStep<int>()];
   }
 
   template <typename... ColTypes, std::size_t... S>
   bool CheckFilterHelper(unsigned int slot, Long64_t entry, TypeList<ColTypes...>, std::index_sequence<S...>)
   {
      // silence "unused parameter" warnings in gcc
      (void)slot;
      (void)entry;
      return fFilter(fValues[slot][S]->template Get<ColTypes>(entry)...);
   }
 
   void InitSlot(TTreeReader *r, unsigned int slot) final
   {
      for (auto &bookedBranch : fDefines.GetColumns())
         bookedBranch.second->InitSlot(r, slot);
      RDFInternal::RColumnReadersInfo info{fColumnNames, fDefines, fIsDefine.data(), fLoopManager->GetDSValuePtrs(),
                                           fLoopManager->GetDataSource()};
      fValues[slot] = RDFInternal::MakeColumnReaders(slot, r, ColumnTypes_t{}, info);
   }
 
   // recursive chain of `Report`s
   void Report(ROOT::RDF::RCutFlowReport &rep) const final { PartialReport(rep); }
 
   void PartialReport(ROOT::RDF::RCutFlowReport &rep) const final
   {
      fPrevData.PartialReport(rep);
      FillReport(rep);
   }
 
   void StopProcessing() final
   {
      ++fNStopsReceived;
      if (fNStopsReceived == fNChildren)
         fPrevData.StopProcessing();
   }
 
   void IncrChildrenCount() final
   {
      ++fNChildren;
      // propagate "children activation" upstream. named filters do the propagation via `TriggerChildrenCount`.
      if (fNChildren == 1 && fName.empty())
         fPrevData.IncrChildrenCount();
   }
 
   void TriggerChildrenCount() final
   {
      R__ASSERT(!fName.empty()); // this method is to only be called on named filters
      fPrevData.IncrChildrenCount();
   }
 
   void AddFilterName(std::vector<std::string> &filters)
   {
      fPrevData.AddFilterName(filters);
      auto name = (HasName() ? fName : "Unnamed Filter");
      filters.push_back(name);
   }
 
   /// Clean-up operations to be performed at the end of a task.
   virtual void FinaliseSlot(unsigned int slot) final
   {
      for (auto &column : fDefines.GetColumns())
         column.second->FinaliseSlot(slot);
 
      for (auto &v : fValues[slot])
         v.reset();
   }
 
   std::shared_ptr<RDFGraphDrawing::GraphNode> GetGraph()
   {
      // Recursively call for the previous node.
      auto prevNode = fPrevData.GetGraph();
      auto prevColumns = prevNode->GetDefinedColumns();
 
      auto thisNode = RDFGraphDrawing::CreateFilterNode(this);
 
      /* If the returned node is not new, there is no need to perform any other operation.
       * This is a likely scenario when building the entire graph in which branches share
       * some nodes. */
      if (!thisNode->GetIsNew()) {
         return thisNode;
      }
 
      auto upmostNode = AddDefinesToGraph(thisNode, fDefines, prevColumns);
 
      // Keep track of the columns defined up to this point.
      thisNode->AddDefinedColumns(fDefines.GetNames());
 
      upmostNode->SetPrevNode(prevNode);
      return thisNode;
   }
};
 
} // ns RDF
} // ns Detail
} // ns ROOT
 
#endif // ROOT_RFILTER