The field for a class representing a collection of elements via TVirtualCollectionProxy.

Objects of such type behave as collections that can be accessed through the corresponding member functions in TVirtualCollectionProxy. For STL collections, these proxies are provided. Custom classes need to implement the corresponding member functions in TVirtualCollectionProxy. At a bare minimum, the user is required to provide an implementation for the following functions in TVirtualCollectionProxy: HasPointers(), GetProperties(), GetValueClass(), GetType(), PushProxy(), PopProxy(), GetFunctionCreateIterators(), GetFunctionNext(), and GetFunctionDeleteTwoIterators().

The collection proxy for a given class can be set via TClass::CopyCollectionProxy().

Definition at line 764 of file RField.hxx.

Classes
class	RCollectionIterableOnce
	Allows for iterating over the elements of a proxied collection. More...

Public Member Functions
	RProxiedCollectionField (RProxiedCollectionField &&other)=default

	RProxiedCollectionField (std::string_view fieldName, std::string_view typeName)

	~RProxiedCollectionField () override=default

void	AcceptVisitor (Detail::RFieldVisitor &visitor) const final

size_t	GetAlignment () const override
	As a rule of thumb, the alignment is equal to the size of the type.

void	GetCollectionInfo (const RClusterIndex &clusterIndex, RClusterIndex collectionStart, ClusterSize_t size) const

void	GetCollectionInfo (NTupleSize_t globalIndex, RClusterIndex collectionStart, ClusterSize_t size) const

size_t	GetValueSize () const override
	The number of bytes taken by a value of the appropriate type.

RProxiedCollectionField &	operator= (RProxiedCollectionField &&other)=default

std::vector< RValue >	SplitValue (const RValue &value) const final
	Creates the list of direct child values given a value for this field.

Public Member Functions inherited from ROOT::Experimental::Detail::RFieldBase
	RFieldBase (const RFieldBase &)=delete

	RFieldBase (RFieldBase &&)=default

	RFieldBase (std::string_view name, std::string_view type, ENTupleStructure structure, bool isSimple, std::size_t nRepetitions=0)
	The constructor creates the underlying column objects and connects them to either a sink or a source.

virtual	~RFieldBase ()

RSchemaIterator	begin ()

RValue	BindValue (void *where)
	Creates a value from a memory location with an already constructed object.

RConstSchemaIterator	cbegin () const

RConstSchemaIterator	cend () const

std::unique_ptr< RFieldBase >	Clone (std::string_view newName) const
	Copies the field and its sub fields using a possibly new name and a new, unconnected set of columns.

void	CommitCluster ()
	Flushes data from active columns to disk and calls CommitClusterImpl.

void	ConnectPageSink (RPageSink &pageSink, NTupleSize_t firstEntry=0)
	Fields and their columns live in the void until connected to a physical page storage.

void	ConnectPageSource (RPageSource &pageSource)

RSchemaIterator	end ()

RBulk	GenerateBulk ()
	The returned bulk is initially empty; RBulk::ReadBulk will construct the array of values.

RValue	GenerateValue ()
	Generates an object of the field type and allocates new initialized memory according to the type.

const ColumnRepresentation_t &	GetColumnRepresentative () const
	Returns the fColumnRepresentative pointee or, if unset, the field's default representative.

std::string	GetDescription () const
	Get the field's description.

virtual std::uint32_t	GetFieldVersion () const
	Indicates an evolution of the mapping scheme from C++ type to columns.

std::string	GetName () const

NTupleSize_t	GetNElements () const

std::size_t	GetNRepetitions () const

DescriptorId_t	GetOnDiskId () const

std::uint32_t	GetOnDiskTypeVersion () const
	Return the C++ type version stored in the field descriptor; only valid after a call to `ConnectPageSource()`

RFieldBase *	GetParent () const

std::string	GetQualifiedFieldName () const
	Returns the field name and parent field names separated by dots ("grandparent.parent.child")

EState	GetState () const

ENTupleStructure	GetStructure () const

std::vector< RFieldBase * >	GetSubFields () const

int	GetTraits () const

std::string	GetType () const

std::string	GetTypeAlias () const

virtual std::uint32_t	GetTypeVersion () const
	Indicates an evolution of the C++ type itself.

bool	HasDefaultColumnRepresentative () const
	Whether or not an explicit column representative was set.

bool	HasReadCallbacks () const

bool	IsSimple () const

RFieldBase &	operator= (const RFieldBase &)=delete

RFieldBase &	operator= (RFieldBase &&)=default

void	SetColumnRepresentative (const ColumnRepresentation_t &representative)
	Fixes a column representative.

void	SetDescription (std::string_view description)

void	SetOnDiskId (DescriptorId_t id)

Protected Member Functions
	RProxiedCollectionField (std::string_view fieldName, std::string_view typeName, std::unique_ptr< Detail::RFieldBase > itemField)
	Constructor used when the value type of the collection is known in advance, e.g. in `RSetField`.

	RProxiedCollectionField (std::string_view fieldName, std::string_view typeName, TClass *classp)
	Constructor used when the value type of the collection is not known in advance, i.e.

std::size_t	AppendImpl (const void *from) final
	Operations on values of complex types, e.g.

std::unique_ptr< Detail::RFieldBase >	CloneImpl (std::string_view newName) const override
	Called by Clone(), which additionally copies the on-disk ID.

void	CommitClusterImpl () final

void	DestroyValue (void *objPtr, bool dtorOnly=false) const override
	Releases the resources acquired during GenerateValue (memory and constructor) This implementation works for types with a trivial destructor and should be overwritten otherwise.

void	GenerateColumnsImpl () final
	Creates the backing columns corresponsing to the field type for writing.

void	GenerateColumnsImpl (const RNTupleDescriptor &desc) final
	Creates the backing columns corresponsing to the field type for reading.

void	GenerateValue (void *where) const override
	Constructs value in a given location of size at least GetValueSize(). Called by the base class' GenerateValue().

const RColumnRepresentations &	GetColumnRepresentations () const final
	Implementations in derived classes should return a static RColumnRepresentations object.

void	ReadGlobalImpl (NTupleSize_t globalIndex, void *to) final

Protected Member Functions inherited from ROOT::Experimental::Detail::RFieldBase
size_t	AddReadCallback (ReadCallback_t func)
	Set a user-defined function to be called after reading a value, giving a chance to inspect and/or modify the value object.

std::size_t	Append (const void *from)
	Write the given value into columns.

void	Attach (std::unique_ptr< Detail::RFieldBase > child)
	Add a new subfield to the list of nested fields.

void	AutoAdjustColumnTypes (const RNTupleWriteOptions &options)
	When connecting a field to a page sink, the field's default column representation is subject to adjustment according to the write options.

const ColumnRepresentation_t &	EnsureCompatibleColumnTypes (const RNTupleDescriptor &desc) const
	Returns the on-disk column types found in the provided descriptor for fOnDiskId.

virtual void	OnConnectPageSource ()
	Called by `ConnectPageSource()` only once connected; derived classes may override this as appropriate.

void	Read (const RClusterIndex &clusterIndex, void *to)

void	Read (NTupleSize_t globalIndex, void *to)
	Populate a single value with data from the field.

std::size_t	ReadBulk (const RBulkSpec &bulkSpec)
	Returns the number of newly available values, that is the number of bools in bulkSpec.fMaskAvail that flipped from false to true.

virtual std::size_t	ReadBulkImpl (const RBulkSpec &bulkSpec)
	General implementation of bulk read.

virtual void	ReadInClusterImpl (const RClusterIndex &clusterIndex, void *to)

void	RemoveReadCallback (size_t idx)

Protected Attributes
Int_t	fCollectionType

RCollectionIterableOnce::RIteratorFuncs	fIFuncsRead
	Two sets of functions to operate on iterators, to be used depending on the access type.

RCollectionIterableOnce::RIteratorFuncs	fIFuncsWrite

std::size_t	fItemSize

ClusterSize_t	fNWritten

Int_t	fProperties

std::unique_ptr< TVirtualCollectionProxy >	fProxy

Protected Attributes inherited from ROOT::Experimental::Detail::RFieldBase
const ColumnRepresentation_t *	fColumnRepresentative = nullptr
	Points into the static vector GetColumnRepresentations().GetSerializationTypes() when SetColumnRepresentative is called.

std::vector< std::unique_ptr< RColumn > >	fColumns
	The columns are connected either to a sink or to a source (not to both); they are owned by the field.

std::uint32_t	fOnDiskTypeVersion = kInvalidTypeVersion
	C++ type version cached from the descriptor after a call to `ConnectPageSource()`

RFieldBase *	fParent
	Sub fields point to their mother field.

RColumn *	fPrincipalColumn
	Points into fColumns.

std::vector< ReadCallback_t >	fReadCallbacks
	List of functions to be called after reading a value.

std::vector< std::unique_ptr< RFieldBase > >	fSubFields
	Collections and classes own sub fields.

int	fTraits = 0
	Properties of the type that allow for optimizations of collections of that type.

std::string	fTypeAlias
	A typedef or using name that was used when creating the field.

Additional Inherited Members
Public Types inherited from ROOT::Experimental::Detail::RFieldBase
using	ColumnRepresentation_t = std::vector< EColumnType >

enum class	EState { kUnconnected , kConnectedToSink , kConnectedToSource }
	During its lifetime, a field undergoes the following possible state transitions: More...

using	RConstSchemaIterator = RSchemaIteratorTemplate< true >

using	RSchemaIterator = RSchemaIteratorTemplate< false >

Static Public Member Functions inherited from ROOT::Experimental::Detail::RFieldBase
static RResult< std::unique_ptr< RFieldBase > >	Create (const std::string &fieldName, const std::string &typeName)
	Factory method to resurrect a field from the stored on-disk type information.

static RResult< void >	EnsureValidFieldName (std::string_view fieldName)
	Check whether a given string is a valid field name.

Static Public Attributes inherited from ROOT::Experimental::Detail::RFieldBase
static constexpr std::uint32_t	kInvalidTypeVersion = -1U

static constexpr int	kTraitMappable = 0x04
	A field of a fundamental type that can be directly mapped via `RField<T>::Map()`, i.e.

static constexpr int	kTraitTriviallyConstructible = 0x01
	No constructor needs to be called, i.e.

static constexpr int	kTraitTriviallyDestructible = 0x02
	The type is cleaned up just by freeing its memory. I.e. DestroyValue() is a no-op.

static constexpr int	kTraitTrivialType = kTraitTriviallyConstructible \| kTraitTriviallyDestructible
	Shorthand for types that are both trivially constructible and destructible.

Static Protected Member Functions inherited from ROOT::Experimental::Detail::RFieldBase
static std::size_t	CallAppendOn (RFieldBase &other, const void *from)
	Allow derived classes to call Append and Read on other (sub) fields.

static void	CallDestroyValueOn (const RFieldBase &other, void *objPtr, bool dtorOnly=false)

static void	CallGenerateValueOn (const RFieldBase &other, void *where)
	Allow derived classes to call GenerateValue(void *) and DestroyValue on other (sub) fields.

static void	CallReadOn (RFieldBase &other, const RClusterIndex &clusterIndex, void *to)

static void	CallReadOn (RFieldBase &other, NTupleSize_t globalIndex, void *to)

static RResult< std::unique_ptr< RFieldBase > >	Create (const std::string &fieldName, const std::string &canonicalType, const std::string &typeAlias)
	Factory method to resurrect a field from the stored on-disk type information.

static RColumn *	GetPrincipalColumnOf (const RFieldBase &other)
	Fields may need direct access to the principal column of their sub fields, e.g. in RRVecField::ReadBulk.

#include <ROOT/RField.hxx>

Inheritance diagram for ROOT::Experimental::RProxiedCollectionField:

[legend]

Constructor & Destructor Documentation

◆ RProxiedCollectionField() [1/4]

ROOT::Experimental::RProxiedCollectionField::RProxiedCollectionField	(	std::string_view	fieldName,
		std::string_view	typeName,
		TClass *	classp
	)

protected

Constructor used when the value type of the collection is not known in advance, i.e.

in the case of custom collections.

Definition at line 1506 of file RField.cxx.

◆ RProxiedCollectionField() [2/4]

ROOT::Experimental::RProxiedCollectionField::RProxiedCollectionField	(	std::string_view	fieldName,
		std::string_view	typeName,
		std::unique_ptr< Detail::RFieldBase >	itemField
	)

protected

Constructor used when the value type of the collection is known in advance, e.g. in RSetField.

Definition at line 1529 of file RField.cxx.

◆ RProxiedCollectionField() [3/4]

ROOT::Experimental::RProxiedCollectionField::RProxiedCollectionField	(	std::string_view	fieldName,
		std::string_view	typeName
	)

Definition at line 1538 of file RField.cxx.

◆ RProxiedCollectionField() [4/4]

ROOT::Experimental::RProxiedCollectionField::RProxiedCollectionField ( RProxiedCollectionField && other )

default

◆ ~RProxiedCollectionField()

ROOT::Experimental::RProxiedCollectionField::~RProxiedCollectionField ( )

overridedefault

Member Function Documentation

◆ AcceptVisitor()

void ROOT::Experimental::RProxiedCollectionField::AcceptVisitor ( Detail::RFieldVisitor & visitor ) const

finalvirtual

Reimplemented from ROOT::Experimental::Detail::RFieldBase.

Definition at line 1673 of file RField.cxx.

◆ AppendImpl()

std::size_t ROOT::Experimental::RProxiedCollectionField::AppendImpl ( const void * from )

finalprotectedvirtual

Operations on values of complex types, e.g.

ones that involve multiple columns or for which no direct column type exists.

Reimplemented from ROOT::Experimental::Detail::RFieldBase.

Definition at line 1588 of file RField.cxx.

◆ CloneImpl()

std::unique_ptr< ROOT::Experimental::Detail::RFieldBase > ROOT::Experimental::RProxiedCollectionField::CloneImpl ( std::string_view newName ) const

overrideprotectedvirtual

Called by Clone(), which additionally copies the on-disk ID.

Implements ROOT::Experimental::Detail::RFieldBase.

Reimplemented in ROOT::Experimental::RSetField.

Definition at line 1581 of file RField.cxx.

◆ CommitClusterImpl()

void ROOT::Experimental::RProxiedCollectionField::CommitClusterImpl ( )

inlinefinalprotectedvirtual

Reimplemented from ROOT::Experimental::Detail::RFieldBase.

Definition at line 864 of file RField.hxx.

◆ DestroyValue()

void ROOT::Experimental::RProxiedCollectionField::DestroyValue	(	void *	objPtr,
		bool	dtorOnly = `false`
	)		const

overrideprotectedvirtual

Releases the resources acquired during GenerateValue (memory and constructor) This implementation works for types with a trivial destructor and should be overwritten otherwise.

Reimplemented from ROOT::Experimental::Detail::RFieldBase.

Definition at line 1648 of file RField.cxx.

◆ GenerateColumnsImpl() [1/2]

void ROOT::Experimental::RProxiedCollectionField::GenerateColumnsImpl ( )

finalprotectedvirtual

Creates the backing columns corresponsing to the field type for writing.

Implements ROOT::Experimental::Detail::RFieldBase.

Definition at line 1632 of file RField.cxx.

◆ GenerateColumnsImpl() [2/2]

void ROOT::Experimental::RProxiedCollectionField::GenerateColumnsImpl ( const RNTupleDescriptor & desc )

finalprotectedvirtual

Creates the backing columns corresponsing to the field type for reading.

The method should to check, using the page source and fOnDiskId, if the column types match and throw if they don't.

Implements ROOT::Experimental::Detail::RFieldBase.

Definition at line 1637 of file RField.cxx.

◆ GenerateValue()

void ROOT::Experimental::RProxiedCollectionField::GenerateValue ( void * where ) const

overrideprotectedvirtual

Constructs value in a given location of size at least GetValueSize(). Called by the base class' GenerateValue().

Implements ROOT::Experimental::Detail::RFieldBase.

Definition at line 1643 of file RField.cxx.

◆ GetAlignment()

size_t ROOT::Experimental::RProxiedCollectionField::GetAlignment ( ) const

inlineoverridevirtual

As a rule of thumb, the alignment is equal to the size of the type.

There are, however, various exceptions to this rule depending on OS and CPU architecture. So enforce the alignment to be explicitly spelled out.

Implements ROOT::Experimental::Detail::RFieldBase.

Reimplemented in ROOT::Experimental::RSetField.

Definition at line 875 of file RField.hxx.

◆ GetCollectionInfo() [1/2]

void ROOT::Experimental::RProxiedCollectionField::GetCollectionInfo	(	const RClusterIndex &	clusterIndex,
		RClusterIndex *	collectionStart,
		ClusterSize_t *	size
	)		const

inline

Definition at line 881 of file RField.hxx.

◆ GetCollectionInfo() [2/2]

void ROOT::Experimental::RProxiedCollectionField::GetCollectionInfo	(	NTupleSize_t	globalIndex,
		RClusterIndex *	collectionStart,
		ClusterSize_t *	size
	)		const

inline

Definition at line 877 of file RField.hxx.

◆ GetColumnRepresentations()

const ROOT::Experimental::Detail::RFieldBase::RColumnRepresentations & ROOT::Experimental::RProxiedCollectionField::GetColumnRepresentations ( ) const

finalprotectedvirtual

Implementations in derived classes should return a static RColumnRepresentations object.

The default implementation does not attach any columns to the field.

Reimplemented from ROOT::Experimental::Detail::RFieldBase.

Definition at line 1624 of file RField.cxx.

◆ GetValueSize()

size_t ROOT::Experimental::RProxiedCollectionField::GetValueSize ( ) const

inlineoverridevirtual

The number of bytes taken by a value of the appropriate type.

Implements ROOT::Experimental::Detail::RFieldBase.

Definition at line 874 of file RField.hxx.

◆ operator=()

RProxiedCollectionField & ROOT::Experimental::RProxiedCollectionField::operator= ( RProxiedCollectionField && other )

default

◆ ReadGlobalImpl()

void ROOT::Experimental::RProxiedCollectionField::ReadGlobalImpl	(	NTupleSize_t	globalIndex,
		void *	to
	)

finalprotectedvirtual

Reimplemented from ROOT::Experimental::Detail::RFieldBase.

Definition at line 1604 of file RField.cxx.

◆ SplitValue()

std::vector< ROOT::Experimental::Detail::RFieldBase::RValue > ROOT::Experimental::RProxiedCollectionField::SplitValue ( const RValue & value ) const

finalvirtual

Creates the list of direct child values given a value for this field.

E.g. a single value for the correct variant or all the elements of a collection. The default implementation assumes no sub values and returns an empty vector.

Reimplemented from ROOT::Experimental::Detail::RFieldBase.

Definition at line 1662 of file RField.cxx.

Member Data Documentation

◆ fCollectionType

Int_t ROOT::Experimental::RProxiedCollectionField::fCollectionType

protected

Definition at line 837 of file RField.hxx.

◆ fIFuncsRead

RCollectionIterableOnce::RIteratorFuncs ROOT::Experimental::RProxiedCollectionField::fIFuncsRead

protected

Two sets of functions to operate on iterators, to be used depending on the access type.

The direction preserves the meaning from TVirtualCollectionProxy, i.e. read from disk / write to disk, respectively

Definition at line 840 of file RField.hxx.

◆ fIFuncsWrite

RCollectionIterableOnce::RIteratorFuncs ROOT::Experimental::RProxiedCollectionField::fIFuncsWrite

protected

Definition at line 841 of file RField.hxx.

◆ fItemSize

std::size_t ROOT::Experimental::RProxiedCollectionField::fItemSize

protected

Definition at line 842 of file RField.hxx.

◆ fNWritten

ClusterSize_t ROOT::Experimental::RProxiedCollectionField::fNWritten

protected

Definition at line 843 of file RField.hxx.

◆ fProperties

Int_t ROOT::Experimental::RProxiedCollectionField::fProperties

protected

Definition at line 836 of file RField.hxx.

◆ fProxy

std::unique_ptr<TVirtualCollectionProxy> ROOT::Experimental::RProxiedCollectionField::fProxy

protected

Definition at line 835 of file RField.hxx.

Libraries for ROOT::Experimental::RProxiedCollectionField:

[legend]

The documentation for this class was generated from the following files:

tree/ntuple/v7/inc/ROOT/RField.hxx
tree/ntuple/v7/src/RField.cxx

Classes

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ RProxiedCollectionField() [1/4]

◆ RProxiedCollectionField() [2/4]

◆ RProxiedCollectionField() [3/4]

◆ RProxiedCollectionField() [4/4]

◆ ~RProxiedCollectionField()

Member Function Documentation

◆ AcceptVisitor()

◆ AppendImpl()

◆ CloneImpl()

◆ CommitClusterImpl()

◆ DestroyValue()

◆ GenerateColumnsImpl() [1/2]

◆ GenerateColumnsImpl() [2/2]

◆ GenerateValue()

◆ GetAlignment()

◆ GetCollectionInfo() [1/2]

◆ GetCollectionInfo() [2/2]

◆ GetColumnRepresentations()

◆ GetValueSize()

◆ operator=()

◆ ReadGlobalImpl()

◆ SplitValue()

Member Data Documentation

◆ fCollectionType

◆ fIFuncsRead

◆ fIFuncsWrite

◆ fItemSize

◆ fNWritten

◆ fProperties

◆ fProxy