template<typename T>
class ROOT::Internal::TDF::TColumnValue< T >

Helper class that updates and returns TTree branches as well as TDataFrame temporary columns.

Template Parameters

T	The type of the column

TDataFrame nodes must access two different types of values during the event loop: values of real branches, for which TTreeReader{Values,Arrays} act as proxies, or temporary columns whose values are generated on the fly. While the type of the value is known at compile time (or just-in-time), it is only at runtime that nodes can check whether a certain value is generated on the fly or not.

TColumnValue abstracts this difference by providing the same interface for both cases and handling the reading or generation of new values transparently. Only one of the two data members fReaderProxy or fValuePtr will be non-null for a given TColumnValue, depending on whether the value comes from a real TTree branch or from a temporary column respectively.

TDataFrame nodes can store tuples of TColumnValues and retrieve an updated value for the column via the Get method.

Definition at line 232 of file TDFNodes.hxx.

Public Member Functions
	TColumnValue ()=default

template<typename U = T, typename std::enable_if< std::is_same< typename TColumnValue< U >::ProxyParam_t, U >::value, int >::type = 0>
T &	Get (Long64_t entry)
	This overload is used to return scalar quantities (i.e. types that are not read into a TArrayBranch) More...

template<typename U = T, typename std::enable_if<!std::is_same< ProxyParam_t, U >::value, int >::type = 0>
TArrayBranch< ProxyParam_t >	Get (Long64_t)
	This overload is used to return arrays (i.e. types that are read into a TArrayBranch) More...

void	MakeProxy (TTreeReader *r, const std::string &bn)

void	Reset ()

void	SetTmpColumn (unsigned int slot, TCustomColumnBase *tmpColumn)

Private Types
enum	EColumnKind { EColumnKind::kTreeValue, EColumnKind::kTreeArray, EColumnKind::kCustomColumn, EColumnKind::kDataSource, EColumnKind::kInvalid }
	TColumnValue has a slightly different behaviour whether the column comes from a TTreeReader, a TDataFrame Define or a TDataSource. More...

using	ProxyParam_t = typename std::conditional< std::is_same< ReaderValueOrArray_t< T >, TTreeReaderValue< T > >::value, T, TakeFirstParameter_t< T > >::type

Private Attributes
bool	fArrayHasBeenChecked = false
	Signal whether we ever checked that the branch we are reading with a TTreeReaderArray stores array elements in contiguous memory. More...

EColumnKind	fColumnKind = EColumnKind::kInvalid

std::vector< TCustomColumnBase * >	fCustomColumns
	Non-owning ptrs to the node responsible for the custom column. Needed when querying custom values. More...

std::vector< T * >	fCustomValuePtrs
	Non-owning ptrs to the value of a custom column. More...

std::vector< T ** >	fDSValuePtrs
	Non-owning ptrs to the value of a data-source column. More...

std::vector< std::unique_ptr< TTreeReaderArray< ProxyParam_t > > >	fReaderArrays
	Owning ptrs to a TTreeReaderArray. Used for non-temporary columns when T == TArrayBranch<U>. More...

std::vector< std::unique_ptr< TTreeReaderValue< T > > >	fReaderValues
	Owning ptrs to a TTreeReaderValue. Used for non-temporary columns when T != TArrayBranch<U> More...

unsigned int	fSlot = std::numeric_limits<unsigned int>::max()
	The slot this value belongs to. Only needed when querying custom column values, it is set in `SetTmpColumn`. More...

#include <ROOT/TDFNodes.hxx>

Member Typedef Documentation

◆ ProxyParam_t

template<typename T >

using ROOT::Internal::TDF::TColumnValue< T >::ProxyParam_t = typename std::conditional<std::is_same<ReaderValueOrArray_t<T>, TTreeReaderValue<T> >::value, T, TakeFirstParameter_t<T> >::type

private

Definition at line 236 of file TDFNodes.hxx.

Member Enumeration Documentation

◆ EColumnKind

template<typename T >

enum ROOT::Internal::TDF::TColumnValue::EColumnKind

strongprivate

TColumnValue has a slightly different behaviour whether the column comes from a TTreeReader, a TDataFrame Define or a TDataSource.

It stores which it is as an enum.

Enumerator
kTreeValue
kTreeArray
kCustomColumn
kDataSource
kInvalid

Definition at line 240 of file TDFNodes.hxx.

Constructor & Destructor Documentation

◆ TColumnValue()

template<typename T >

ROOT::Internal::TDF::TColumnValue< T >::TColumnValue ( )

default

Member Function Documentation

◆ Get() [1/2]

template<typename T >

template<typename U , typename std::enable_if< std::is_same< typename TColumnValue< U >::ProxyParam_t, U >::value, int >::type >

T & ROOT::Internal::TDF::TColumnValue< T >::Get ( Long64_t entry )

This overload is used to return scalar quantities (i.e. types that are not read into a TArrayBranch)

Definition at line 835 of file TDFNodes.hxx.

◆ Get() [2/2]

template<typename T >

template<typename U = T, typename std::enable_if<!std::is_same< ProxyParam_t, U >::value, int >::type = 0>

TArrayBranch<ProxyParam_t> ROOT::Internal::TDF::TColumnValue< T >::Get ( Long64_t )

inline

This overload is used to return arrays (i.e. types that are read into a TArrayBranch)

Definition at line 288 of file TDFNodes.hxx.

◆ MakeProxy()

template<typename T >

void ROOT::Internal::TDF::TColumnValue< T >::MakeProxy	(	TTreeReader *	r,
		const std::string &	bn
	)

inline

Definition at line 269 of file TDFNodes.hxx.

◆ Reset()

template<typename T >

void ROOT::Internal::TDF::TColumnValue< T >::Reset ( void )

inline

Definition at line 312 of file TDFNodes.hxx.

◆ SetTmpColumn()

template<typename T >

void ROOT::Internal::TDF::TColumnValue< T >::SetTmpColumn	(	unsigned int	slot,
		TCustomColumnBase *	tmpColumn
	)

Definition at line 810 of file TDFNodes.hxx.

Member Data Documentation

◆ fArrayHasBeenChecked

template<typename T >

bool ROOT::Internal::TDF::TColumnValue< T >::fArrayHasBeenChecked = false

private

Signal whether we ever checked that the branch we are reading with a TTreeReaderArray stores array elements in contiguous memory.

Only used when T == TArrayBranch<U>.

Definition at line 262 of file TDFNodes.hxx.

template<typename T >

unsigned int ROOT::Internal::TDF::TColumnValue< T >::fSlot = std::numeric_limits<unsigned int>::max()

private

The slot this value belongs to. Only needed when querying custom column values, it is set in SetTmpColumn.

Definition at line 244 of file TDFNodes.hxx.

Libraries for ROOT::Internal::TDF::TColumnValue< T >:

[legend]

template<typename T> class ROOT::Internal::TDF::TColumnValue< T >

Public Member Functions

Private Types

Private Attributes

Member Typedef Documentation

◆ ProxyParam_t

Member Enumeration Documentation

◆ EColumnKind

Constructor & Destructor Documentation

◆ TColumnValue()

Member Function Documentation

◆ Get() [1/2]

◆ Get() [2/2]

◆ MakeProxy()

◆ Reset()

◆ SetTmpColumn()

Member Data Documentation

◆ fArrayHasBeenChecked

◆ fColumnKind

◆ fCustomColumns

◆ fCustomValuePtrs

◆ fDSValuePtrs

◆ fReaderArrays

◆ fReaderValues

◆ fSlot

template<typename T>
class ROOT::Internal::TDF::TColumnValue< T >