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ROOT::Experimental::RVariantField Class Reference

The generic field for std::variant types.

Definition at line 1349 of file RField.hxx.

Classes

class  RVariantDeleter
 

Public Member Functions

 RVariantField (RVariantField &&other)=default
 
 RVariantField (std::string_view fieldName, const std::vector< RFieldBase * > &itemFields)
 
 ~RVariantField () override=default
 
size_t GetAlignment () const final
 As a rule of thumb, the alignment is equal to the size of the type.
 
size_t GetValueSize () const final
 The number of bytes taken by a value of the appropriate type.
 
RVariantFieldoperator= (RVariantField &&other)=default
 
- Public Member Functions inherited from ROOT::Experimental::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 ()=default
 
virtual void AcceptVisitor (Detail::RFieldVisitor &visitor) const
 
RSchemaIterator begin ()
 
RValue BindValue (std::shared_ptr< void > objPtr)
 Creates a value from a memory location with an already constructed object.
 
RConstSchemaIterator cbegin () const
 
RConstSchemaIterator cend () const
 
std::unique_ptr< RFieldBaseClone (std::string_view newName) const
 Copies the field and its sub fields using a possibly new name and a new, unconnected set of columns.
 
RBulk CreateBulk ()
 The returned bulk is initially empty; RBulk::ReadBulk will construct the array of values.
 
template<typename T >
std::unique_ptr< T, typename RCreateObjectDeleter< T >::deleter > CreateObject () const
 Generates an object of the field type and allocates new initialized memory according to the type.
 
template<>
std::unique_ptr< void, typename RFieldBase::RCreateObjectDeleter< void >::deleter > CreateObject () const
 
template<>
std::unique_ptr< void, typename ROOT::Experimental::RFieldBase::RCreateObjectDeleter< void >::deleter > CreateObject () const
 
RValue CreateValue ()
 Generates an object of the field type and wraps the created object in a shared pointer and returns it an RValue connected to the field.
 
RSchemaIterator end ()
 
const ColumnRepresentation_tGetColumnRepresentative () const
 Returns the fColumnRepresentative pointee or, if unset, the field's default representative.
 
std::string GetDescription () const
 Get the field's description.
 
std::string GetFieldName () const
 
virtual std::uint32_t GetFieldVersion () const
 Indicates an evolution of the mapping scheme from C++ type to columns.
 
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()
 
const RFieldBaseGetParent () 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 ()
 
std::vector< const RFieldBase * > GetSubFields () const
 
int GetTraits () const
 
std::string GetTypeAlias () const
 
std::string GetTypeName () 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
 
RFieldBaseoperator= (const RFieldBase &)=delete
 
RFieldBaseoperator= (RFieldBase &&)=default
 
void SetColumnRepresentative (const ColumnRepresentation_t &representative)
 Fixes a column representative.
 
void SetDescription (std::string_view description)
 
void SetOnDiskId (DescriptorId_t id)
 
virtual std::vector< RValueSplitValue (const RValue &value) const
 Creates the list of direct child values given a value for this field.
 

Protected Member Functions

std::size_t AppendImpl (const void *from) final
 Operations on values of complex types, e.g.
 
std::unique_ptr< RFieldBaseCloneImpl (std::string_view newName) const final
 Called by Clone(), which additionally copies the on-disk ID.
 
void CommitClusterImpl () final
 
void ConstructValue (void *where) const override
 Constructs value in a given location of size at least GetValueSize(). Called by the base class' CreateValue().
 
void GenerateColumnsImpl () final
 Implementations in derived classes should create the backing columns corresponsing to the field type for writing.
 
void GenerateColumnsImpl (const RNTupleDescriptor &desc) final
 Implementations in derived classes should create the backing columns corresponsing to the field type for reading.
 
const RColumnRepresentationsGetColumnRepresentations () const final
 Implementations in derived classes should return a static RColumnRepresentations object.
 
std::unique_ptr< RDeleterGetDeleter () const final
 
void ReadGlobalImpl (NTupleSize_t globalIndex, void *to) final
 
- Protected Member Functions inherited from ROOT::Experimental::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< 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_tEnsureCompatibleColumnTypes (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 (NTupleSize_t globalIndex, void *to)
 Populate a single value with data from the field.
 
void Read (RClusterIndex clusterIndex, void *to)
 
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 (RClusterIndex clusterIndex, void *to)
 
void RemoveReadCallback (size_t idx)
 

Static Private Member Functions

static std::uint32_t GetTag (const void *variantPtr, std::size_t tagOffset)
 Extracts the index from an std::variant and transforms it into the 1-based index used for the switch column.
 
static std::string GetTypeList (const std::vector< RFieldBase * > &itemFields)
 
static void SetTag (void *variantPtr, std::size_t tagOffset, std::uint32_t tag)
 

Private Attributes

size_t fMaxAlignment = 1
 
size_t fMaxItemSize = 0
 
std::vector< ClusterSize_t::ValueTypefNWritten
 
size_t fTagOffset = 0
 In the std::variant memory layout, at which byte number is the index stored.
 

Additional Inherited Members

- Public Types inherited from ROOT::Experimental::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::RFieldBase
static std::vector< RCheckResultCheck (const std::string &fieldName, const std::string &typeName)
 Checks if the given type is supported by RNTuple.
 
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::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. the destructor performs 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::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 CallConstructValueOn (const RFieldBase &other, void *where)
 Allow derived classes to call ConstructValue(void *) and GetDeleter on other (sub) fields.
 
static void CallReadOn (RFieldBase &other, NTupleSize_t globalIndex, void *to)
 
static void CallReadOn (RFieldBase &other, RClusterIndex clusterIndex, void *to)
 
static RResult< std::unique_ptr< RFieldBase > > Create (const std::string &fieldName, const std::string &canonicalType, const std::string &typeAlias, bool fContinueOnError=false)
 Factory method to resurrect a field from the stored on-disk type information.
 
static std::unique_ptr< RDeleterGetDeleterOf (const RFieldBase &other)
 
static Internal::RColumnGetPrincipalColumnOf (const RFieldBase &other)
 Fields may need direct access to the principal column of their sub fields, e.g. in RRVecField::ReadBulk.
 
- Protected Attributes inherited from ROOT::Experimental::RFieldBase
const ColumnRepresentation_tfColumnRepresentative = nullptr
 Points into the static vector GetColumnRepresentations().GetSerializationTypes() when SetColumnRepresentative is called.
 
std::vector< std::unique_ptr< Internal::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()
 
RFieldBasefParent
 Sub fields point to their mother field.
 
Internal::RColumnfPrincipalColumn
 Points into fColumns.
 
std::vector< ReadCallback_tfReadCallbacks
 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.
 

#include <ROOT/RField.hxx>

Inheritance diagram for ROOT::Experimental::RVariantField:
[legend]

Constructor & Destructor Documentation

◆ RVariantField() [1/2]

ROOT::Experimental::RVariantField::RVariantField ( std::string_view  fieldName,
const std::vector< RFieldBase * > &  itemFields 
)

Definition at line 3198 of file RField.cxx.

◆ RVariantField() [2/2]

ROOT::Experimental::RVariantField::RVariantField ( RVariantField &&  other)
default

◆ ~RVariantField()

ROOT::Experimental::RVariantField::~RVariantField ( )
overridedefault

Member Function Documentation

◆ AppendImpl()

std::size_t ROOT::Experimental::RVariantField::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::RFieldBase.

Definition at line 3243 of file RField.cxx.

◆ CloneImpl()

std::unique_ptr< ROOT::Experimental::RFieldBase > ROOT::Experimental::RVariantField::CloneImpl ( std::string_view  newName) const
finalprotectedvirtual

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

Implements ROOT::Experimental::RFieldBase.

Definition at line 3219 of file RField.cxx.

◆ CommitClusterImpl()

void ROOT::Experimental::RVariantField::CommitClusterImpl ( )
finalprotectedvirtual

Reimplemented from ROOT::Experimental::RFieldBase.

Definition at line 3322 of file RField.cxx.

◆ ConstructValue()

void ROOT::Experimental::RVariantField::ConstructValue ( void *  where) const
overrideprotectedvirtual

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

Implements ROOT::Experimental::RFieldBase.

Definition at line 3291 of file RField.cxx.

◆ GenerateColumnsImpl() [1/2]

void ROOT::Experimental::RVariantField::GenerateColumnsImpl ( )
finalprotectedvirtual

Implementations in derived classes should create the backing columns corresponsing to the field type for writing.

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

Reimplemented from ROOT::Experimental::RFieldBase.

Definition at line 3280 of file RField.cxx.

◆ GenerateColumnsImpl() [2/2]

void ROOT::Experimental::RVariantField::GenerateColumnsImpl ( const RNTupleDescriptor )
finalprotectedvirtual

Implementations in derived classes should create the backing columns corresponsing to the field type for reading.

The default implementation does not attach any columns to the field. The method should check, using the page source and fOnDiskId, if the column types match and throw if they don't.

Reimplemented from ROOT::Experimental::RFieldBase.

Definition at line 3285 of file RField.cxx.

◆ GetAlignment()

size_t ROOT::Experimental::RVariantField::GetAlignment ( ) const
inlinefinalvirtual

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::RFieldBase.

Definition at line 1398 of file RField.hxx.

◆ GetColumnRepresentations()

const ROOT::Experimental::RFieldBase::RColumnRepresentations & ROOT::Experimental::RVariantField::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::RFieldBase.

Definition at line 3274 of file RField.cxx.

◆ GetDeleter()

std::unique_ptr< ROOT::Experimental::RFieldBase::RDeleter > ROOT::Experimental::RVariantField::GetDeleter ( ) const
finalprotectedvirtual

Reimplemented from ROOT::Experimental::RFieldBase.

Definition at line 3307 of file RField.cxx.

◆ GetTag()

std::uint32_t ROOT::Experimental::RVariantField::GetTag ( const void *  variantPtr,
std::size_t  tagOffset 
)
staticprivate

Extracts the index from an std::variant and transforms it into the 1-based index used for the switch column.

Definition at line 3231 of file RField.cxx.

◆ GetTypeList()

std::string ROOT::Experimental::RVariantField::GetTypeList ( const std::vector< RFieldBase * > &  itemFields)
staticprivate

Definition at line 3187 of file RField.cxx.

◆ GetValueSize()

size_t ROOT::Experimental::RVariantField::GetValueSize ( ) const
finalvirtual

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

Implements ROOT::Experimental::RFieldBase.

Definition at line 3317 of file RField.cxx.

◆ operator=()

RVariantField & ROOT::Experimental::RVariantField::operator= ( RVariantField &&  other)
default

◆ ReadGlobalImpl()

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

Reimplemented from ROOT::Experimental::RFieldBase.

Definition at line 3257 of file RField.cxx.

◆ SetTag()

void ROOT::Experimental::RVariantField::SetTag ( void *  variantPtr,
std::size_t  tagOffset,
std::uint32_t  tag 
)
staticprivate

Definition at line 3237 of file RField.cxx.

Member Data Documentation

◆ fMaxAlignment

size_t ROOT::Experimental::RVariantField::fMaxAlignment = 1
private

Definition at line 1365 of file RField.hxx.

◆ fMaxItemSize

size_t ROOT::Experimental::RVariantField::fMaxItemSize = 0
private

Definition at line 1364 of file RField.hxx.

◆ fNWritten

std::vector<ClusterSize_t::ValueType> ROOT::Experimental::RVariantField::fNWritten
private

Definition at line 1368 of file RField.hxx.

◆ fTagOffset

size_t ROOT::Experimental::RVariantField::fTagOffset = 0
private

In the std::variant memory layout, at which byte number is the index stored.

Definition at line 1367 of file RField.hxx.

Libraries for ROOT::Experimental::RVariantField:

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