v8  8.4.371(node14.15.0)
V8 is Google's open source JavaScript engine
PersistentBase< T > Class Template Reference

#include <v8.h>

Public Member Functions

V8_INLINE void Reset ()
 
template<class S >
V8_INLINE void Reset (Isolate *isolate, const Local< S > &other)
 
template<class S >
V8_INLINE void Reset (Isolate *isolate, const PersistentBase< S > &other)
 
V8_INLINE bool IsEmpty () const
 
V8_INLINE void Empty ()
 
V8_INLINE Local< T > Get (Isolate *isolate) 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 PersistentBase< S > &that) const
 
template<class S >
V8_INLINE bool operator!= (const Local< S > &that) const
 
template<typename P >
V8_INLINE void SetWeak (P *parameter, typename WeakCallbackInfo< P >::Callback callback, WeakCallbackType type)
 
V8_INLINE void SetWeak ()
 
template<typename P >
V8_INLINE P * ClearWeak ()
 
V8_INLINE void ClearWeak ()
 
V8_INLINE void AnnotateStrongRetainer (const char *label)
 
V8_INLINE bool IsWeak () const
 
V8_INLINE void SetWrapperClassId (uint16_t class_id)
 
V8_INLINE uint16_t WrapperClassId () const
 
 PersistentBase (const PersistentBase &other)=delete
 
void operator= (const PersistentBase &)=delete
 
template<class S >
void Reset (Isolate *isolate, const Local< S > &other)
 
template<class S >
void Reset (Isolate *isolate, const PersistentBase< S > &other)
 

Friends

class Isolate
 
class Utils
 
template<class F >
class Local
 
template<class F1 , class F2 >
class Persistent
 
template<class F >
class Global
 
template<class F >
class PersistentBase
 
template<class F >
class ReturnValue
 
template<class F1 , class F2 , class F3 >
class PersistentValueMapBase
 
template<class F1 , class F2 >
class PersistentValueVector
 
class Object
 

Detailed Description

template<class T>
class v8::PersistentBase< T >

An object reference that is independent of any handle scope. Where a Local handle only lives as long as the HandleScope in which it was allocated, a PersistentBase handle remains valid until it is explicitly disposed using Reset().

A persistent handle contains a reference to a storage cell within the V8 engine which holds an object value and which is updated by the garbage collector whenever the object is moved. A new storage cell can be created using the constructor or PersistentBase::Reset and existing handles can be disposed using PersistentBase::Reset.

Definition at line 95 of file v8.h.

Constructor & Destructor Documentation

◆ PersistentBase()

PersistentBase ( const PersistentBase< T > &  other)
delete

Member Function Documentation

◆ AnnotateStrongRetainer()

void AnnotateStrongRetainer ( const char *  label)

Annotates the strong handle with the given label, which is then used by the heap snapshot generator as a name of the edge from the root to the handle. The function does not take ownership of the label and assumes that the label is valid as long as the handle is valid.

Definition at line 10824 of file v8.h.

◆ ClearWeak() [1/2]

V8_INLINE P* ClearWeak ( )

◆ ClearWeak() [2/2]

P * ClearWeak ( )
inline

Definition at line 565 of file v8.h.

◆ Empty()

V8_INLINE void Empty ( )
inline

Definition at line 501 of file v8.h.

◆ Get()

V8_INLINE Local<T> Get ( Isolate isolate) const
inline

Definition at line 503 of file v8.h.

References V8::Local.

◆ IsEmpty()

V8_INLINE bool IsEmpty ( ) const
inline

Definition at line 500 of file v8.h.

◆ IsWeak()

bool IsWeak

Returns true if the handle's reference is weak.

Definition at line 10764 of file v8.h.

References Internals::GetNodeState(), and Internals::kNodeStateIsWeakValue.

◆ operator!=() [1/2]

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

Definition at line 531 of file v8.h.

◆ operator!=() [2/2]

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

Definition at line 526 of file v8.h.

◆ operator=()

void operator= ( const PersistentBase< T > &  )
delete

◆ operator==() [1/2]

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

Definition at line 517 of file v8.h.

◆ operator==() [2/2]

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

Definition at line 508 of file v8.h.

◆ Reset() [1/5]

void Reset

If non-empty, destroy the underlying storage cell IsEmpty() will return true after this call.

Definition at line 10773 of file v8.h.

◆ Reset() [2/5]

V8_INLINE void Reset ( Isolate isolate,
const Local< S > &  other 
)

If non-empty, destroy the underlying storage cell and create a new one with the contents of other if other is non empty

◆ Reset() [3/5]

void Reset ( Isolate isolate,
const Local< S > &  other 
)

Definition at line 10782 of file v8.h.

◆ Reset() [4/5]

V8_INLINE void Reset ( Isolate isolate,
const PersistentBase< S > &  other 
)

If non-empty, destroy the underlying storage cell and create a new one with the contents of other if other is non empty

◆ Reset() [5/5]

void Reset ( Isolate isolate,
const PersistentBase< S > &  other 
)

Definition at line 10792 of file v8.h.

◆ SetWeak() [1/2]

void SetWeak

Turns this handle into a weak phantom handle without finalization callback. The handle will be reset automatically when the garbage collector detects that the object is no longer reachable. A related function Isolate::NumberOfPhantomHandleResetsSinceLastCall returns how many phantom handles were reset by the garbage collector.

Definition at line 10812 of file v8.h.

◆ SetWeak() [2/2]

V8_INLINE void SetWeak ( P *  parameter,
typename WeakCallbackInfo< P >::Callback  callback,
WeakCallbackType  type 
)

Install a finalization callback on this object. NOTE: There is no guarantee as to when or even if the callback is invoked. The invocation is performed solely on a best effort basis. As always, GC-based finalization should not be relied upon for any critical form of resource management!

The callback is supposed to reset the handle. No further V8 API may be called in this callback. In case additional work involving V8 needs to be done, a second callback can be scheduled using WeakCallbackInfo<void>::SetSecondPassCallback.

Definition at line 10803 of file v8.h.

References V8::WeakCallbackInfo.

◆ SetWrapperClassId()

void SetWrapperClassId ( uint16_t  class_id)

Assigns a wrapper class ID to the handle.

Definition at line 10830 of file v8.h.

References Internals::kNodeClassIdOffset.

◆ WrapperClassId()

uint16_t WrapperClassId

Returns the class ID previously assigned to this handle or 0 if no class ID was previously assigned.

Definition at line 10840 of file v8.h.

References Internals::kNodeClassIdOffset.

Friends And Related Function Documentation

◆ Global

friend class Global
friend

Definition at line 598 of file v8.h.

◆ Isolate

friend class Isolate
friend

Definition at line 593 of file v8.h.

◆ Local

friend class Local
friend

Definition at line 595 of file v8.h.

◆ Object

friend class Object
friend

Definition at line 604 of file v8.h.

◆ Persistent

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 596 of file v8.h.

◆ PersistentBase

friend class PersistentBase
friend

Definition at line 599 of file v8.h.

◆ PersistentValueMapBase

friend class PersistentValueMapBase
friend

Definition at line 602 of file v8.h.

◆ PersistentValueVector

friend class PersistentValueVector
friend

Definition at line 603 of file v8.h.

◆ ReturnValue

friend class ReturnValue
friend

Definition at line 600 of file v8.h.

◆ Utils

friend class Utils
friend

Definition at line 594 of file v8.h.


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