#include <v8-local-handle.h>

Inheritance diagram for v8::Local< T >:

Collaboration diagram for v8::Local< T >:

Public Member Functions
	Local ()=default

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

T *	operator-> () const

T *	operator* () const

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

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

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

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

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

Public Member Functions inherited from v8::api_internal::IndirectHandleBase
bool	IsEmpty () const

void	Clear ()

Public Member Functions inherited from v8::api_internal::StackAllocated< false >
	StackAllocated ()=default

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

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

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

static 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 v8::LocalBase< T >
	LocalBase ()=default

	LocalBase (internal::Address *location)

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

Protected Member Functions inherited from v8::api_internal::IndirectHandleBase
	IndirectHandleBase ()=default

	IndirectHandleBase (const IndirectHandleBase &other)=default

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

	IndirectHandleBase (internal::Address *location)

internal::Address	ptr () const

internal::Address *const &	slot () const

internal::Address *&	slot ()

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

Protected Member Functions inherited from v8::api_internal::StackAllocated< false >
	StackAllocated (no_checking_tag)

	StackAllocated (const StackAllocated &other, no_checking_tag)

void	VerifyOnStack () const

Static Protected Member Functions inherited from v8::LocalBase< T >
static LocalBase< T >	New (Isolate *isolate, internal::Address value)

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

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

Static Protected Attributes inherited from v8::api_internal::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.

Examples: process.cc, and shell.cc.

Constructor & Destructor Documentation

◆ Local() [1/2]

template<class T >

v8::Local< T >::Local ( )

inlinedefault

◆ Local() [2/2]

template<class T >

template<class S >

v8::Local< T >::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>.

Member Function Documentation

◆ As()

template<class T >

template<class S >

Local< S > v8::Local< T >::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.

Examples: shell.cc.

◆ Cast()

template<class T >

template<class S >

static Local< T > v8::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.

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◆ New() [1/3]

template<class T >

static Local< T > v8::Local< T >::New	(	Isolate *	isolate,
		const BasicTracedReference< T > &	that
	)

inlinestatic

◆ New() [2/3]

template<class T >

static Local< T > v8::Local< T >::New	(	Isolate *	isolate,
		const PersistentBase< T > &	that
	)

inlinestatic

◆ New() [3/3]

template<class T >

static Local< T > v8::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.

Examples: process.cc.

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◆ operator!=() [1/2]

template<class T >

template<class S >

bool v8::Local< T >::operator!= ( const Local< S > & that ) const

inline

◆ operator!=() [2/2]

template<class T >

template<class S >

bool v8::Local< T >::operator!= ( const Persistent< S > & that ) const

inline

◆ operator*()

template<class T >

T * v8::Local< T >::operator* ( ) const

inline

◆ operator->()

template<class T >

T * v8::Local< T >::operator-> ( ) const

inline

◆ operator==() [1/2]

template<class T >

template<class S >

bool v8::Local< T >::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.

◆ operator==() [2/2]

template<class T >

template<class S >

bool v8::Local< T >::operator== ( const PersistentBase< S > & that ) const

inline

Friends And Related Function Documentation

◆ Context

template<class T >

friend class Context

friend

◆ debug::ConsoleCallArguments

template<class T >

friend class debug::ConsoleCallArguments

friend

◆ EscapableHandleScope

template<class T >

friend class EscapableHandleScope

friend

◆ Eternal

template<class T >

template<class F >

friend class Eternal

friend

◆ False

template<class T >

Local< Boolean > False ( Isolate * isolate )

friend

◆ FunctionCallbackInfo

template<class T >

template<class F >

friend class FunctionCallbackInfo

friend

◆ Global

template<class T >

template<class F >

friend class Global

friend

Examples: process.cc.

◆ HandleScope

template<class T >

friend class HandleScope

friend

◆ internal::CustomArguments

template<class T >

template<class F >

friend class internal::CustomArguments

friend

◆ internal::HandleHelper

template<class T >

friend class internal::HandleHelper

friend

◆ internal::LocalUnchecked< T >

template<class T >

friend class internal::LocalUnchecked< T >

friend

◆ internal::SamplingHeapProfiler

template<class T >

friend class internal::SamplingHeapProfiler

friend

◆ InternalEscapableScope

template<class T >

friend class InternalEscapableScope

friend

◆ Isolate

template<class T >

friend class Isolate

friend

◆ Local

template<class T >

template<class F >

friend class Local

friend

◆ MaybeLocal

template<class T >

template<class F >

friend class MaybeLocal

friend

◆ Null

template<class T >

Local< Primitive > Null ( Isolate * isolate )

friend

◆ Object

template<class T >

friend class Object

friend

◆ 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.

◆ PersistentValueMapBase

template<class T >

template<class F1 , class F2 , class F3 >

friend class PersistentValueMapBase

friend

◆ PersistentValueVector

template<class T >

template<class F1 , class F2 >

friend class PersistentValueVector

friend

◆ Private

template<class T >

friend class Private

friend

◆ PropertyCallbackInfo

template<class T >

template<class F >

friend class PropertyCallbackInfo

friend

◆ ReturnValue

template<class T >

template<class F >

friend class ReturnValue

friend

◆ String

template<class T >

friend class String

friend

◆ Traced

template<class T >

template<class F >

friend class Traced

friend

◆ TracedReferenceBase

template<class T >

friend class TracedReferenceBase

friend

◆ True

template<class T >

Local< Boolean > True ( Isolate * isolate )

friend

◆ Undefined

template<class T >

Local< Primitive > Undefined ( Isolate * isolate )

friend

◆ Utils

template<class T >

friend class Utils

friend

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 Function 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