V8 API Reference Guide for node.js v5.12.0
Public Member Functions | Static Public Member Functions | Friends | List of all members
v8::Local< T > Class Template Reference

#include <v8.h>

Public Member Functions

template<class S >
V8_INLINE Local (Local< S > that)
 
V8_INLINE bool IsEmpty () const
 
V8_INLINE void Clear ()
 
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 ()
 

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)
 

Friends

class Utils
 
template<class F >
class Eternal
 
template<class F >
class PersistentBase
 
template<class F , class M >
class Persistent
 
template<class F >
class Local
 
template<class F >
class MaybeLocal
 
template<class F >
class FunctionCallbackInfo
 
template<class F >
class PropertyCallbackInfo
 
class String
 
class Object
 
class Context
 
template<class F >
class internal::CustomArguments
 
class HandleScope
 
class EscapableHandleScope
 
template<class F1 , class F2 , class F3 >
class PersistentValueMapBase
 
template<class F1 , class F2 >
class PersistentValueVector
 
Local< PrimitiveUndefined (Isolate *isolate)
 
Local< PrimitiveNull (Isolate *isolate)
 
Local< BooleanTrue (Isolate *isolate)
 
Local< BooleanFalse (Isolate *isolate)
 

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. 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.

Constructor & Destructor Documentation

template<class T>
template<class S >
V8_INLINE 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

template<class T>
V8_INLINE void v8::Local< T >::Clear ( )
inline

Sets the handle to be empty. IsEmpty() will then return true.

template<class T>
V8_INLINE bool v8::Local< T >::IsEmpty ( ) const
inline

Returns true if the handle is empty.

template<class T>
Local< T > v8::Local< T >::New ( Isolate isolate,
Local< T >  that 
)
static

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.

template<class T>
template<class S >
V8_INLINE bool v8::Local< T >::operator!= ( const Local< S > &  that) const
inline

Checks whether two handles are different. Returns true if only one of the handles is empty, or if the objects to which they refer are different. The handles' references are not checked.

template<class T>
template<class S >
V8_INLINE bool v8::Local< T >::operator== ( const Local< S > &  that) const
inline

Checks whether two handles are the same. Returns true if both are empty, or if the objects to which they refer are identical. The handles' references are not checked.


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