#include <visitor.h>

Inheritance diagram for Visitor:

Data Structures
class	Key

Public Member Functions
	Visitor (Key)

virtual	~Visitor ()=default

template<typename T>
void	Trace (const Member< T > &member)

template<typename T>
void	Trace (const WeakMember< T > &weak_member)

template<typename T>
void	TraceMultiple (const subtle::UncompressedMember< T > *start, size_t len)

template<typename T, std::enable_if_t<!std::is_same_v< Member< T >, subtle::UncompressedMember< T > > > * = nullptr>
void	TraceMultiple (const Member< T > *start, size_t len)

template<typename T>
void	Trace (const T &object)

template<typename T>
void	TraceMultiple (const T *start, size_t len)

template<typename T, void(T::*)(const LivenessBroker &) method>
void	RegisterWeakCallbackMethod (const T *object)

template<typename K, typename V>
void	Trace (const EphemeronPair< K, V > &ephemeron_pair)

template<typename KeyType, typename ValueType>
void	TraceEphemeron (const WeakMember< KeyType > &weak_member_key, const Member< ValueType > *member_value)

template<typename KeyType, typename ValueType>
void	TraceEphemeron (const WeakMember< KeyType > &weak_member_key, const ValueType *value)

template<typename T>
void	TraceStrongly (const WeakMember< T > &weak_member)

template<typename T>
void	TraceStrongContainer (const T *object)

template<typename T>
void	TraceWeakContainer (const T object, WeakCallback callback, const void callback_data)

template<typename T>
void	RegisterMovableReference (const T **slot)

virtual void	RegisterWeakCallback (WeakCallback callback, const void *data)

virtual V8_WARN_UNUSED_RESULT bool	DeferTraceToMutatorThreadIfConcurrent (const void *parameter, TraceCallback callback, size_t deferred_size)

Protected Member Functions
virtual void	Visit (const void *self, TraceDescriptor)

virtual void	VisitWeak (const void self, TraceDescriptor, WeakCallback, const void weak_member)

virtual void	VisitEphemeron (const void key, const void value, TraceDescriptor value_desc)

virtual void	VisitWeakContainer (const void self, TraceDescriptor strong_desc, TraceDescriptor weak_desc, WeakCallback callback, const void data)

virtual void	HandleMovableReference (const void **)

virtual void	VisitMultipleUncompressedMember (const void *start, size_t len, TraceDescriptorCallback get_trace_descriptor)

Friends
template<typename T, typename WeaknessPolicy, typename LocationPolicy, typename CheckingPolicy>
class	internal::BasicCrossThreadPersistent

template<typename T, typename WeaknessPolicy, typename LocationPolicy, typename CheckingPolicy>
class	internal::BasicPersistent

class	internal::ConservativeTracingVisitor

class	internal::VisitorBase

Detailed Description

Visitor passed to trace methods. All managed pointers must have called the Visitor's trace method on them.

class Foo final : public GarbageCollected<Foo> {
 public:
  void Trace(Visitor* visitor) const {
    visitor->Trace(foo_);
    visitor->Trace(weak_foo_);
  }
 private:
  Member<Foo> foo_;
  WeakMember<Foo> weak_foo_;
};

Definition at line 75 of file visitor.h.

Constructor & Destructor Documentation

◆ Visitor()

Visitor ( Key )

inlineexplicit

Definition at line 83 of file visitor.h.

Referenced by JSVisitor::JSVisitor().

◆ ~Visitor()

virtual ~Visitor ( )

virtualdefault

Member Function Documentation

◆ DeferTraceToMutatorThreadIfConcurrent()

virtual V8_WARN_UNUSED_RESULT bool DeferTraceToMutatorThreadIfConcurrent	(	const void *	parameter,
		TraceCallback	callback,
		size_t	deferred_size )

inlinevirtual

Defers tracing an object from a concurrent thread to the mutator thread. Should be called by Trace methods of types that are not safe to trace concurrently.

Parameters

parameter	tells the trace callback which object was deferred.
callback	to be invoked for tracing on the mutator thread.
deferred_size	size of deferred object.

Returns: false if the object does not need to be deferred (i.e. currently traced on the mutator thread) and true otherwise (i.e. currently traced on a concurrent thread).

Definition at line 366 of file visitor.h.

References V8_WARN_UNUSED_RESULT.

◆ HandleMovableReference()

virtual void HandleMovableReference ( const void ** )

inlineprotectedvirtual

Definition at line 381 of file visitor.h.

Referenced by RegisterMovableReference().

◆ RegisterMovableReference()

template<typename T>

void RegisterMovableReference ( const T ** slot )

inline

Registers a slot containing a reference to an object allocated on a compactable space. Such references maybe be arbitrarily moved by the GC.

Parameters

slot	location of reference to object that might be moved by the GC. The slot must contain an uncompressed pointer.

Definition at line 336 of file visitor.h.

References HandleMovableReference(), cppgc::IsGarbageCollectedMixinTypeV, and IsAllocatedOnCompactableSpace< T >::value.

◆ RegisterWeakCallback()

virtual void RegisterWeakCallback	(	WeakCallback	callback,
		const void *	data )

inlinevirtual

Registers a weak callback that is invoked during garbage collection.

Parameters

callback	to be invoked.
data	custom data that is passed to the callback.

Definition at line 351 of file visitor.h.

Referenced by RegisterWeakCallbackMethod().

◆ RegisterWeakCallbackMethod()

template<typename T, void(T::*)(const LivenessBroker &) method>

void RegisterWeakCallbackMethod ( const T * object )

inline

Registers a weak callback method on the object of type T. See LivenessBroker for an usage example.

Parameters

object of type T specifying a weak callback method.

Definition at line 207 of file visitor.h.

References RegisterWeakCallback().

Referenced by Trace().

◆ Trace() [1/4]

template<typename K, typename V>

void Trace ( const EphemeronPair< K, V > & ephemeron_pair )

inline

Trace method for EphemeronPair.

Parameters

ephemeron_pair EphemeronPair reference weakly retaining a key object and strongly retaining a value object in case the key object is alive.

Definition at line 218 of file visitor.h.

References EphemeronPair< K, V >::ClearValueIfKeyIsDead(), EphemeronPair< K, V >::key, RegisterWeakCallbackMethod(), TraceEphemeron(), and EphemeronPair< K, V >::value.

◆ Trace() [2/4]

template<typename T>

void Trace ( const Member< T > & member )

inline

Trace method for Member.

Parameters

member Member reference retaining an object.

Definition at line 93 of file visitor.h.

References CPPGC_DCHECK, and cppgc::kSentinelPointer.

◆ Trace() [3/4]

template<typename T>

void Trace ( const T & object )

inline

Trace method for inlined objects that are not allocated themselves but otherwise follow managed heap layout and have a Trace() method.

Parameters

object reference of the inlined object.

Definition at line 169 of file visitor.h.

References TraceTraitBase< T >::Trace().

◆ Trace() [4/4]

template<typename T>

void Trace ( const WeakMember< T > & weak_member )

inline

Trace method for WeakMember.

Parameters

weak_member WeakMember reference weakly retaining an object.

Definition at line 105 of file visitor.h.

References CPPGC_DCHECK, TraceTraitBase< T >::GetTraceDescriptor(), cppgc::kSentinelPointer, IsAllocatedOnCompactableSpace< T >::value, and VisitWeak().

◆ TraceEphemeron() [1/2]

template<typename KeyType, typename ValueType>

void TraceEphemeron	(	const WeakMember< KeyType > &	weak_member_key,
		const Member< ValueType > *	member_value )

inline

Trace method for a single ephemeron. Used for tracing a raw ephemeron in which the key and value are kept separately.

Parameters

weak_member_key	WeakMember reference weakly retaining a key object.
member_value	Member reference with ephemeron semantics.

Definition at line 233 of file visitor.h.

References TraceDescriptor::base_object_payload, CPPGC_DCHECK, TraceTraitBase< T >::GetTraceDescriptor(), and VisitEphemeron().

Referenced by EphemeronPair< K, V >::Trace(), and Trace().

◆ TraceEphemeron() [2/2]

template<typename KeyType, typename ValueType>

void TraceEphemeron	(	const WeakMember< KeyType > &	weak_member_key,
		const ValueType *	value )

inline

Trace method for a single ephemeron. Used for tracing a raw ephemeron in which the key and value are kept separately. Note that this overload is for non-GarbageCollected values that can be traced though.

Parameters

key	`WeakMember` reference weakly retaining a key object.
value	Reference weakly retaining a value object. Note that `ValueType` here should not be `Member`. It is expected that `TraceTrait<ValueType>::GetTraceDescriptor(value)` returns a `TraceDescriptor` with a null base pointer but a valid trace method.

Definition at line 266 of file visitor.h.

References TraceDescriptor::base_object_payload, CPPGC_DCHECK, TraceTraitBase< T >::GetTraceDescriptor(), cppgc::IsGarbageCollectedOrMixinTypeV, and VisitEphemeron().

◆ TraceMultiple() [1/3]

template<typename T, std::enable_if_t<!std::is_same_v< Member< T >, subtle::UncompressedMember< T > > > * = nullptr>

void TraceMultiple	(	const Member< T > *	start,
		size_t	len )

inline

Definition at line 150 of file visitor.h.

References TraceTraitBase< T >::GetTraceDescriptor().

◆ TraceMultiple() [2/3]

template<typename T>

void TraceMultiple	(	const subtle::UncompressedMember< T > *	start,
		size_t	len )

inline

Definition at line 139 of file visitor.h.

References TraceTraitBase< T >::GetTraceDescriptor(), and VisitMultipleUncompressedMember().

◆ TraceMultiple() [3/3]

template<typename T>

void TraceMultiple	(	const T *	start,
		size_t	len )

inline

Definition at line 181 of file visitor.h.

References TraceTraitBase< T >::Trace().

◆ TraceStrongContainer()

template<typename T>

void TraceStrongContainer ( const T * object )

inline

Trace method for retaining containers strongly.

Parameters

object reference to the container.

Definition at line 307 of file visitor.h.

◆ TraceStrongly()

template<typename T>

void TraceStrongly ( const WeakMember< T > & weak_member )

inline

Trace method that strongifies a WeakMember.

Parameters

weak_member WeakMember reference retaining an object.

Definition at line 295 of file visitor.h.

References CPPGC_DCHECK, and cppgc::kSentinelPointer.

◆ TraceWeakContainer()

template<typename T>

void TraceWeakContainer	(	const T *	object,
		WeakCallback	callback,
		const void *	callback_data )

inline

Trace method for retaining containers weakly. Note that weak containers should emit write barriers.

Parameters

object	reference to the container.
callback	to be invoked.
callback_data	custom data that is passed to the callback.

Definition at line 320 of file visitor.h.

References TraceTraitBase< T >::GetTraceDescriptor(), and VisitWeakContainer().

◆ Visit()

virtual void Visit	(	const void *	self,
		TraceDescriptor	)

inlineprotectedvirtual

Definition at line 373 of file visitor.h.

Referenced by VisitMultipleUncompressedMember().

◆ VisitEphemeron()

virtual void VisitEphemeron	(	const void *	key,
		const void *	value,
		TraceDescriptor	value_desc )

inlineprotectedvirtual

Definition at line 376 of file visitor.h.

Referenced by TraceEphemeron(), and TraceEphemeron().

◆ VisitMultipleUncompressedMember()

virtual void VisitMultipleUncompressedMember	(	const void *	start,
		size_t	len,
		TraceDescriptorCallback	get_trace_descriptor )

inlineprotectedvirtual

Definition at line 383 of file visitor.h.

References RawPointer::LoadAtomic(), and Visit().

Referenced by TraceMultiple().

◆ VisitWeak()

virtual void VisitWeak	(	const void *	self,
		TraceDescriptor	,
		WeakCallback	,
		const void *	weak_member )

inlineprotectedvirtual

Definition at line 374 of file visitor.h.

Referenced by Trace().

◆ VisitWeakContainer()

virtual void VisitWeakContainer	(	const void *	self,
		TraceDescriptor	strong_desc,
		TraceDescriptor	weak_desc,
		WeakCallback	callback,
		const void *	data )

inlineprotectedvirtual

Definition at line 378 of file visitor.h.

Referenced by TraceWeakContainer().

Friends And Related Symbol Documentation

◆ internal::BasicCrossThreadPersistent

template<typename T, typename WeaknessPolicy, typename LocationPolicy, typename CheckingPolicy>

friend class internal::BasicCrossThreadPersistent

friend

Definition at line 450 of file visitor.h.

◆ internal::BasicPersistent

template<typename T, typename WeaknessPolicy, typename LocationPolicy, typename CheckingPolicy>

friend class internal::BasicPersistent

friend

Definition at line 453 of file visitor.h.

◆ internal::ConservativeTracingVisitor

friend class internal::ConservativeTracingVisitor

friend

Definition at line 454 of file visitor.h.

◆ internal::VisitorBase

friend class internal::VisitorBase

friend

Definition at line 455 of file visitor.h.

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

include/cppgc/visitor.h

Data Structures

Public Member Functions

Protected Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ Visitor()

◆ ~Visitor()

Member Function Documentation

◆ DeferTraceToMutatorThreadIfConcurrent()

◆ HandleMovableReference()

◆ RegisterMovableReference()

◆ RegisterWeakCallback()

◆ RegisterWeakCallbackMethod()

◆ Trace() [1/4]

◆ Trace() [2/4]

◆ Trace() [3/4]

◆ Trace() [4/4]

◆ TraceEphemeron() [1/2]

◆ TraceEphemeron() [2/2]

◆ TraceMultiple() [1/3]

◆ TraceMultiple() [2/3]

◆ TraceMultiple() [3/3]

◆ TraceStrongContainer()

◆ TraceStrongly()

◆ TraceWeakContainer()

◆ Visit()

◆ VisitEphemeron()

◆ VisitMultipleUncompressedMember()

◆ VisitWeak()

◆ VisitWeakContainer()

Friends And Related Symbol Documentation

◆ internal::BasicCrossThreadPersistent

◆ internal::BasicPersistent

◆ internal::ConservativeTracingVisitor

◆ internal::VisitorBase