#include <v8-local-handle.h>

Inheritance diagram for Local< T >:

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Collaboration diagram for Local< T >:

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Public Member Functions
V8_INLINE	Local ()=default

template<class S >
V8_INLINE	Local (Local< S > that)

V8_INLINE T *	operator-> () const

V8_INLINE T *	operator* () const

template<class S >
V8_INLINE bool	operator== (const Local< S > &that) const

template<class S >
V8_INLINE bool	operator== (const PersistentBase< S > &that) const

template<class S >
V8_INLINE bool	operator!= (const Local< S > &that) const

template<class S >
V8_INLINE bool	operator!= (const Persistent< S > &that) const

template<class S >
V8_INLINE Local< S >	As () const

Public Member Functions inherited from IndirectHandleBase
V8_INLINE bool	IsEmpty () const

V8_INLINE void	Clear ()

Public Member Functions inherited from StackAllocated< false >
V8_INLINE	StackAllocated ()=default

Static Public Member Functions
template<class S >
static V8_INLINE Local< T >	Cast (Local< S > that)

static V8_INLINE Local< T >	New (Isolate *isolate, Local< T > that)

static V8_INLINE Local< T >	New (Isolate *isolate, const PersistentBase< T > &that)

static V8_INLINE Local< T >	New (Isolate *isolate, const BasicTracedReference< T > &that)

Friends
class	TracedReferenceBase

class	Utils

template<class F >
class	Eternal

template<class F >
class	Global

template<class F >
class	Local

template<class F >
class	MaybeLocal

template<class F , class M >
class	Persistent

template<class F >
class	FunctionCallbackInfo

template<class F >
class	PropertyCallbackInfo

class	String

class	Object

class	Context

class	Isolate

class	Private

template<class F >
class	internal::CustomArguments

class	HandleScope

class	EscapableHandleScope

class	InternalEscapableScope

template<class F1 , class F2 , class F3 >
class	PersistentValueMapBase

template<class F1 , class F2 >
class	PersistentValueVector

template<class F >
class	ReturnValue

template<class F >
class	Traced

class	internal::SamplingHeapProfiler

class	internal::HandleHelper

class	debug::ConsoleCallArguments

class	internal::LocalUnchecked< T >

Local< Primitive >	Undefined (Isolate *isolate)

Local< Primitive >	Null (Isolate *isolate)

Local< Boolean >	True (Isolate *isolate)

Local< Boolean >	False (Isolate *isolate)

Additional Inherited Members
Protected Member Functions inherited from LocalBase< T >
V8_INLINE	LocalBase ()=default

V8_INLINE	LocalBase (internal::Address *location)

template<typename S >
V8_INLINE	LocalBase (const LocalBase< S > &other)

Protected Member Functions inherited from IndirectHandleBase
V8_INLINE	IndirectHandleBase ()=default

V8_INLINE	IndirectHandleBase (const IndirectHandleBase &other)=default

V8_INLINE IndirectHandleBase &	operator= (const IndirectHandleBase &that)=default

V8_INLINE	IndirectHandleBase (internal::Address *location)

V8_INLINE internal::Address	ptr () const

V8_INLINE internal::Address *const &	slot () const

V8_INLINE internal::Address *&	slot ()

template<typename T , bool check_null = false>
V8_INLINE T *	value () const

Protected Member Functions inherited from StackAllocated< false >
V8_INLINE	StackAllocated (no_checking_tag)

V8_INLINE	StackAllocated (const StackAllocated &other, no_checking_tag)

V8_INLINE void	VerifyOnStack () const

Static Protected Member Functions inherited from LocalBase< T >
static V8_INLINE LocalBase< T >	New (Isolate *isolate, internal::Address value)

static V8_INLINE LocalBase< T >	New (Isolate isolate, T that)

static V8_INLINE LocalBase< T >	FromSlot (internal::Address *slot)

Static Protected Attributes inherited from StackAllocated< false >
static constexpr no_checking_tag	do_not_check

Detailed Description

template<class T>
class v8::Local< T >

An object reference managed by the v8 garbage collector.

All objects returned from v8 have to be tracked by the garbage collector so that it knows that the objects are still alive. Also, because the garbage collector may move objects, it is unsafe to point directly to an object. Instead, all objects are stored in handles which are known by the garbage collector and updated whenever an object moves. Handles should always be passed by value (except in cases like out-parameters) and they should never be allocated on the heap.

There are two types of handles: local and persistent handles.

Local handles are light-weight and transient and typically used in local operations. They are managed by HandleScopes. That means that a HandleScope must exist on the stack when they are created and that they are only valid inside of the HandleScope active during their creation. For passing a local handle to an outer HandleScope, an EscapableHandleScope and its Escape() method must be used.

Persistent handles can be used when storing objects across several independent operations and have to be explicitly deallocated when they're no longer used.

It is safe to extract the object stored in the handle by dereferencing the handle (for instance, to extract the Object* from a Local<Object>); the value will still be governed by a handle behind the scenes and the same rules apply to these values as to their handles.

Definition at line 252 of file v8-local-handle.h.

Constructor & Destructor Documentation

◆ Local() [1/2]

template<class T >

V8_INLINE Local ( )

default

◆ Local() [2/2]

template<class T >

template<class S >

V8_INLINE Local ( Local< S > that )

inline

This check fails when trying to convert between incompatible handles. For example, converting from a Local<String> to a Local<Number>.

Definition at line 263 of file v8-local-handle.h.

Member Function Documentation

◆ As()

template<class T >

template<class S >

V8_INLINE Local< S > As ( ) const

inline

Calling this is equivalent to Local<S>::Cast(). In particular, this is only valid if the handle actually refers to a value of the target type.

Definition at line 329 of file v8-local-handle.h.

◆ Cast()

template<class T >

template<class S >

static V8_INLINE Local< T > Cast ( Local< S > that )

inlinestatic

Cast a handle to a subclass, e.g. Local<Value> to Local<Object>. This is only valid if the handle actually refers to a value of the target type.

Definition at line 313 of file v8-local-handle.h.

References IndirectHandleBase::IsEmpty().

◆ New() [1/3]

template<class T >

static V8_INLINE Local< T > New	(	Isolate *	isolate,
		const BasicTracedReference< T > &	that
	)

inlinestatic

Definition at line 347 of file v8-local-handle.h.

◆ New() [2/3]

template<class T >

static V8_INLINE Local< T > New	(	Isolate *	isolate,
		const PersistentBase< T > &	that
	)

inlinestatic

Definition at line 342 of file v8-local-handle.h.

◆ New() [3/3]

template<class T >

static V8_INLINE Local< T > New	(	Isolate *	isolate,
		Local< T >	that
	)

inlinestatic

Create a local handle for the content of another handle. The referee is kept alive by the local handle even when the original handle is destroyed/disposed.

Definition at line 338 of file v8-local-handle.h.

Referenced by PersistentValueMapBase< K, V, Traits >::Get(), PersistentBase< T >::Get(), TracedReferenceBase::Get(), BasicTracedReference< T >::Get(), Context::GetEmbedderData(), Object::GetInternalField(), PersistentValueMapBase< K, V, Traits >::PersistentValueReference::NewLocal(), PersistentValueMap< K, V, Traits >::SetUnique(), and GlobalValueMap< K, V, Traits >::SetUnique().

◆ operator!=() [1/2]

template<class T >

template<class S >

V8_INLINE bool operator!= ( const Local< S > & that ) const

inline

Definition at line 298 of file v8-local-handle.h.

◆ operator!=() [2/2]

template<class T >

template<class S >

V8_INLINE bool operator!= ( const Persistent< S > & that ) const

inline

Definition at line 303 of file v8-local-handle.h.

◆ operator*()

template<class T >

V8_INLINE T * operator* ( ) const

inline

Definition at line 274 of file v8-local-handle.h.

◆ operator->()

template<class T >

V8_INLINE T * operator-> ( ) const

inline

Definition at line 272 of file v8-local-handle.h.

◆ operator==() [1/2]

template<class T >

template<class S >

V8_INLINE bool operator== ( const Local< S > & that ) const

inline

Checks whether two handles are equal or different. They are equal iff they are both empty or they are both non-empty and the objects to which they refer are physically equal.

If both handles refer to JS objects, this is the same as strict non-equality. For primitives, such as numbers or strings, a true return value does not indicate that the values aren't equal in the JavaScript sense. Use Value::StrictEquals() to check primitives for equality.

Definition at line 288 of file v8-local-handle.h.

◆ operator==() [2/2]

template<class T >

template<class S >

V8_INLINE bool operator== ( const PersistentBase< S > & that ) const

inline

Definition at line 293 of file v8-local-handle.h.

Friends And Related Symbol Documentation

◆ Context

template<class T >

friend class Context

friend

Definition at line 371 of file v8-local-handle.h.

◆ debug::ConsoleCallArguments

template<class T >

friend class debug::ConsoleCallArguments

friend

Definition at line 393 of file v8-local-handle.h.

◆ EscapableHandleScope

template<class T >

friend class EscapableHandleScope

friend

Definition at line 381 of file v8-local-handle.h.

◆ Eternal

template<class T >

template<class F >

friend class Eternal

friend

Definition at line 356 of file v8-local-handle.h.

◆ False

template<class T >

Local< Boolean > False ( Isolate * isolate )

friend

Definition at line 863 of file v8-primitive.h.

◆ FunctionCallbackInfo

template<class T >

template<class F >

friend class FunctionCallbackInfo

friend

Definition at line 366 of file v8-local-handle.h.

◆ Global

template<class T >

template<class F >

friend class Global

friend

Definition at line 358 of file v8-local-handle.h.

◆ HandleScope

template<class T >

friend class HandleScope

friend

Definition at line 380 of file v8-local-handle.h.

◆ internal::CustomArguments

template<class T >

template<class F >

friend class internal::CustomArguments

friend

Definition at line 375 of file v8-local-handle.h.

◆ internal::HandleHelper

template<class T >

friend class internal::HandleHelper

friend

Definition at line 392 of file v8-local-handle.h.

◆ internal::LocalUnchecked< T >

template<class T >

friend class internal::LocalUnchecked< T >

friend

Definition at line 393 of file v8-local-handle.h.

◆ internal::SamplingHeapProfiler

template<class T >

friend class internal::SamplingHeapProfiler

friend

Definition at line 391 of file v8-local-handle.h.

◆ InternalEscapableScope

template<class T >

friend class InternalEscapableScope

friend

Definition at line 382 of file v8-local-handle.h.

◆ Isolate

template<class T >

friend class Isolate

friend

Definition at line 372 of file v8-local-handle.h.

◆ Local

template<class T >

template<class F >

friend class Local

friend

Definition at line 360 of file v8-local-handle.h.

◆ MaybeLocal

template<class T >

template<class F >

friend class MaybeLocal

friend

Definition at line 362 of file v8-local-handle.h.

◆ Null

template<class T >

Local< Primitive > Null ( Isolate * isolate )

friend

Definition at line 847 of file v8-primitive.h.

◆ Object

template<class T >

friend class Object

friend

Definition at line 370 of file v8-local-handle.h.

◆ Persistent

template<class T >

template<class F , class M >

friend class Persistent

friend

Persistent is a way to create a strong pointer from an off-heap object to another on-heap object. As long as the Persistent handle is alive the GC will keep the object pointed to alive. The Persistent handle is always a GC root from the point of view of the GC. Persistent must be constructed and destructed in the same thread.

Definition at line 364 of file v8-local-handle.h.

◆ PersistentValueMapBase

template<class T >

template<class F1 , class F2 , class F3 >

friend class PersistentValueMapBase

friend

Definition at line 384 of file v8-local-handle.h.

◆ PersistentValueVector

template<class T >

template<class F1 , class F2 >

friend class PersistentValueVector

friend

Definition at line 386 of file v8-local-handle.h.

◆ Private

template<class T >

friend class Private

friend

Definition at line 373 of file v8-local-handle.h.

◆ PropertyCallbackInfo

template<class T >

template<class F >

friend class PropertyCallbackInfo

friend

Definition at line 368 of file v8-local-handle.h.

◆ ReturnValue

template<class T >

template<class F >

friend class ReturnValue

friend

Definition at line 388 of file v8-local-handle.h.

◆ String

template<class T >

friend class String

friend

Definition at line 369 of file v8-local-handle.h.

◆ Traced

template<class T >

template<class F >

friend class Traced

friend

Definition at line 390 of file v8-local-handle.h.

◆ TracedReferenceBase

template<class T >

friend class TracedReferenceBase

friend

Definition at line 353 of file v8-local-handle.h.

◆ True

template<class T >

Local< Boolean > True ( Isolate * isolate )

friend

Definition at line 855 of file v8-primitive.h.

◆ Undefined

template<class T >

Local< Primitive > Undefined ( Isolate * isolate )

friend

Definition at line 839 of file v8-primitive.h.

◆ Utils

template<class T >

friend class Utils

friend

Definition at line 354 of file v8-local-handle.h.

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

include/v8-local-handle.h

Public Member Functions

Static Public Member Functions

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Local() [1/2]

◆ Local() [2/2]

Member Function Documentation

◆ As()

◆ Cast()

◆ New() [1/3]

◆ New() [2/3]

◆ New() [3/3]

◆ operator!=() [1/2]

◆ operator!=() [2/2]

◆ operator*()

◆ operator->()

◆ operator==() [1/2]

◆ operator==() [2/2]

Friends And Related Symbol Documentation

◆ Context

◆ debug::ConsoleCallArguments

◆ EscapableHandleScope

◆ Eternal

◆ False

◆ FunctionCallbackInfo

◆ Global

◆ HandleScope

◆ internal::CustomArguments

◆ internal::HandleHelper

◆ internal::LocalUnchecked< T >

◆ internal::SamplingHeapProfiler

◆ InternalEscapableScope

◆ Isolate

◆ Local

◆ MaybeLocal

◆ Null

◆ Object

◆ Persistent

◆ PersistentValueMapBase

◆ PersistentValueVector

◆ Private

◆ PropertyCallbackInfo

◆ ReturnValue

◆ String

◆ Traced

◆ TracedReferenceBase

◆ True

◆ Undefined

◆ Utils