Persistent< T > Class Template Reference

#include <v8.h>

Inheritance diagram for Persistent< T >:

Collaboration diagram for Persistent< T >:

Public Member Functions
	Persistent ()
template<class S >
	Persistent (Persistent< S > that)
template<class S >
	Persistent (S *that)
template<class S >
	Persistent (Handle< S > that)
template<class S >
Persistent< S >	As ()
void	Dispose ()
void	MakeWeak (void *parameters, WeakReferenceCallback callback)
void	ClearWeak ()
void	MarkIndependent ()
bool	IsNearDeath () const
bool	IsWeak () const
void	SetWrapperClassId (uint16_t class_id)
Public Member Functions inherited from Handle< T >
	Handle ()
	Handle (T *val)
template<class S >
	Handle (Handle< S > that)
bool	IsEmpty () const
void	Clear ()
T *	operator-> () const
T *	operator* () const
template<class S >
bool	operator== (Handle< S > that) const
template<class S >
bool	operator!= (Handle< S > that) const
template<class S >
Handle< S >	As ()

Static Public Member Functions
template<class S >
static Persistent< T >	Cast (Persistent< S > that)
static Persistent< T >	New (Handle< T > that)
Static Public Member Functions inherited from Handle< T >
template<class S >
static Handle< T >	Cast (Handle< S > that)

Friends
class	ImplementationUtilities
class	ObjectTemplate

Detailed Description

template<class T>
class v8::Persistent< 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 Persistent handle remains valid until it is explicitly disposed.

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 Persistent::New and existing handles can be disposed using Persistent::Dispose. Since persistent handles are passed by value you may have many persistent handle objects that point to the same storage cell. For instance, if you pass a persistent handle as an argument to a function you will not get two different storage cells but rather two references to the same storage cell.

Definition at line 319 of file v8.h.

Constructor & Destructor Documentation

Persistent() [1/4]

Persistent

inline

Creates an empty persistent handle that doesn't point to any storage cell.

Definition at line 4072 of file v8.h.

References V8::Handle.

Persistent() [2/4]

Persistent ( Persistent< S >  that )

inline

Creates a persistent handle for the same storage cell as the specified handle. This constructor allows you to pass persistent handles as arguments by value and to assign between persistent handles. However, attempting to assign between incompatible persistent handles, for instance from a Persistent<String> to a Persistent<Number> will cause a compile-time error. Assigning between compatible persistent handles, for instance assigning a Persistent<String> to a variable declared as Persistent<Value>, is allowed as String is a subclass of Value.

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

Definition at line 338 of file v8.h.

References V8::Handle.

Persistent() [3/4]

Persistent ( S *  that )

inline

Definition at line 348 of file v8.h.

References V8::Handle.

Persistent() [4/4]

Persistent ( Handle< S >  that )

inlineexplicit

"Casts" a plain handle which is known to be a persistent handle to a persistent handle.

Definition at line 354 of file v8.h.

References V8::Handle.

Member Function Documentation

As()

Persistent<S> As ( )

inline

Definition at line 366 of file v8.h.

References V8::Persistent.

Cast()

static Persistent<T> Cast ( Persistent< S >  that )

inlinestatic

Definition at line 357 of file v8.h.

References V8::Persistent.

ClearWeak()

void ClearWeak

inline

Clears the weak reference to this object.

Definition at line 4082 of file v8.h.

Dispose()

void Dispose

inline

Releases the storage cell referenced by this persistent handle. Does not remove the reference to the cell from any handles. This handle's reference, and any other references to the storage cell remain and IsEmpty will still return false.

Definition at line 4065 of file v8.h.

IsNearDeath()

bool IsNearDeath

inline

Checks if the handle holds the only reference to an object.

Definition at line 4051 of file v8.h.

IsWeak()

bool IsWeak

inline

Returns true if the handle's reference is weak.

Definition at line 4058 of file v8.h.

MakeWeak()

void MakeWeak ( void *  parameters, WeakReferenceCallback  callback  )

inline

Make the reference to this object weak. When only weak handles refer to the object, the garbage collector will perform a callback to the given V8::WeakReferenceCallback function, passing it the object reference and the given parameters.

Definition at line 4075 of file v8.h.

MarkIndependent()

void MarkIndependent

inline

Marks the reference to this object independent. Garbage collector is free to ignore any object groups containing this object. Weak callback for an independent handle should not assume that it will be preceded by a global GC prologue callback or followed by a global GC epilogue callback.

Definition at line 4087 of file v8.h.

New()

Persistent< T > New ( Handle< T >  that )

inlinestatic

Creates a new persistent handle for an existing local or persistent handle.

Definition at line 4043 of file v8.h.

References V8::Persistent.

SetWrapperClassId()

void SetWrapperClassId ( uint16_t  class_id )

inline

Assigns a wrapper class ID to the handle. See RetainedObjectInfo interface description in v8-profiler.h for details.

Definition at line 4092 of file v8.h.

Friends And Related Function Documentation

ImplementationUtilities

friend class ImplementationUtilities

friend

Definition at line 421 of file v8.h.

ObjectTemplate

friend class ObjectTemplate

friend

Definition at line 422 of file v8.h.

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

• include/v8.h