DPL: drop obsolete TreeToTable code

Now using the arrow::Dataset API.

Author: ktf

Framework/Core/CMakeLists.txt

@@ -250,7 +250,6 @@ add_executable(o2-test-framework-core
               test/test_Variants.cxx
               test/test_WorkflowHelpers.cxx
               test/test_WorkflowSerialization.cxx
-              test/test_TreeToTable.cxx
               test/test_DataOutputDirector.cxx
               test/unittest_SimpleOptionsRetriever.cxx
               test/unittest_DataSpecUtils.cxx
@@ -348,7 +347,6 @@ foreach(b
         EventMixing
         HistogramRegistry
         TableToTree
-        TreeToTable
         ExternalFairMQDeviceProxies
         )
   o2_add_executable(benchmark-${b}

Framework/Core/include/Framework/DataAllocator.h

@@ -233,15 +233,6 @@ class DataAllocator
     return tb;
   }
 
-  template <typename T, typename... Args>
-    requires(requires { static_cast<struct TreeToTable>(std::declval<std::decay_t<T>>()); })
-  decltype(auto) make(const Output& spec, Args... args)
-  {
-    auto t2t = std::move(LifetimeHolder<TreeToTable>(new std::decay_t<T>(args...)));
-    adopt(spec, t2t);
-    return t2t;
-  }
-
   template <typename T, typename... Args>
     requires(requires { static_cast<struct FragmentToBatch>(std::declval<std::decay_t<T>>()); })
   decltype(auto) make(const Output& spec, Args... args)
@@ -288,11 +279,6 @@ class DataAllocator
   void
     adopt(const Output& spec, LifetimeHolder<struct TableBuilder>&);
 
-  /// Adopt a Tree2Table in the framework and serialise / send
-  /// it as an Arrow table to all consumers of @a spec once done
-  void
-    adopt(const Output& spec, LifetimeHolder<struct TreeToTable>&);
-
   /// Adopt a Source2Batch in the framework and serialise / send
   /// it as an Arrow Dataset to all consumers of @a spec once done
   void

Framework/Core/include/Framework/TableTreeHelpers.h

@@ -36,19 +36,6 @@ namespace o2::framework
 //    OR t2t.addBranch(column.get(), field.get()), ...;
 //  . t2t.process();
 //
-// .............................................................................
-// -----------------------------------------------------------------------------
-// TreeToTable allows to fill the contents of a given TTree to an arrow::Table
-//  ColumnIterator is used by TreeToTable
-//
-// To copy the contents of a tree tr to a table ta do:
-//  . TreeToTable t2t(tr);
-//  . t2t.addColumn(columnname1); t2t.addColumn(columnname2); ...
-//    OR
-//    t2t.addAllColumns();
-//  . auto ta = t2t.process();
-//
-// .............................................................................
 struct ROOTTypeInfo {
   EDataType type;
   char suffix[3];
@@ -58,29 +45,6 @@ struct ROOTTypeInfo {
 auto arrowTypeFromROOT(EDataType type, int size);
 auto basicROOTTypeFromArrow(arrow::Type::type id);
 
-class BranchToColumn
-{
- public:
-  BranchToColumn(TBranch* branch, bool VLA, std::string name, EDataType type, int listSize, arrow::MemoryPool* pool);
-  //  BranchToColumn(TBranch* branch, TBranch* sizeBranch, std::string name, EDataType type, arrow::MemoryPool* pool);
-  ~BranchToColumn() = default;
-  TBranch* branch();
-
-  std::pair<std::shared_ptr<arrow::ChunkedArray>, std::shared_ptr<arrow::Field>> read(TBuffer* buffer);
-
- private:
-  TBranch* mBranch = nullptr;
-  bool mVLA = false;
-  std::string mColumnName;
-  EDataType mType;
-  std::shared_ptr<arrow::DataType> mArrowType;
-  arrow::ArrayBuilder* mValueBuilder = nullptr;
-  std::unique_ptr<arrow::ArrayBuilder> mListBuilder = nullptr;
-  int mListSize = 1;
-  std::unique_ptr<arrow::ArrayBuilder> mBuilder = nullptr;
-  arrow::MemoryPool* mPool = nullptr;
-};
-
 class ColumnToBranch
 {
  public:
@@ -127,24 +91,6 @@ class TableToTree
   std::vector<std::unique_ptr<ColumnToBranch>> mColumnReaders;
 };
 
-class TreeToTable
-{
- public:
-  TreeToTable(arrow::MemoryPool* pool = arrow::default_memory_pool());
-  void setLabel(const char* label);
-  void addAllColumns(TTree* tree, std::vector<std::string>&& names = {});
-  void fill(TTree*);
-  std::shared_ptr<arrow::Table> finalize();
-
- private:
-  arrow::MemoryPool* mArrowMemoryPool;
-  std::vector<std::unique_ptr<BranchToColumn>> mBranchReaders;
-  std::string mTableLabel;
-  std::shared_ptr<arrow::Table> mTable;
-
-  void addReader(TBranch* branch, std::string const& name, bool VLA);
-};
-
 class FragmentToBatch
 {
  public:

Framework/Core/src/DataAllocator.cxx

@@ -241,38 +241,6 @@ void DataAllocator::adopt(const Output& spec, LifetimeHolder<TableBuilder>& tb)
   context.addBuffer(std::move(header), buffer, std::move(finalizer), routeIndex);
 }
 
-void DataAllocator::adopt(const Output& spec, LifetimeHolder<TreeToTable>& t2t)
-{
-  auto& timingInfo = mRegistry.get<TimingInfo>();
-  RouteIndex routeIndex = matchDataHeader(spec, timingInfo.timeslice);
-
-  auto header = headerMessageFromOutput(spec, routeIndex, o2::header::gSerializationMethodArrow, 0);
-  auto& context = mRegistry.get<ArrowContext>();
-
-  auto creator = [transport = context.proxy().getOutputTransport(routeIndex)](size_t s) -> std::unique_ptr<fair::mq::Message> {
-    return transport->CreateMessage(s);
-  };
-  auto buffer = std::make_shared<FairMQResizableBuffer>(creator);
-
-  t2t.callback = [buffer = buffer, transport = context.proxy().getOutputTransport(routeIndex)](TreeToTable& tree) {
-    // Serialization happens in here, so that we can
-    // get rid of the intermediate tree 2 table object, saving memory.
-    auto table = tree.finalize();
-    doWriteTable(buffer, table.get());
-    // deletion happens in the caller
-  };
-
-  /// To finalise this we write the table to the buffer.
-  /// FIXME: most likely not a great idea. We should probably write to the buffer
-  ///        directly in the TableBuilder, incrementally.
-  auto finalizer = [](std::shared_ptr<FairMQResizableBuffer> b) -> void {
-    // This is empty because we already serialised the object when
-    // the LifetimeHolder goes out of scope.
-  };
-
-  context.addBuffer(std::move(header), buffer, std::move(finalizer), routeIndex);
-}
-
 void DataAllocator::adopt(const Output& spec, LifetimeHolder<FragmentToBatch>& f2b)
 {
   auto& timingInfo = mRegistry.get<TimingInfo>();