v8  5.8.282(node8.0.0)
V8 is Google's open source JavaScript engine
FunctionTemplate Class Reference

#include <v8.h>

Inheritance diagram for FunctionTemplate:
Collaboration diagram for FunctionTemplate:

Public Member Functions

 V8_DEPRECATE_SOON ("Use maybe version", Local< Function > GetFunction())
 
V8_WARN_UNUSED_RESULT MaybeLocal< FunctionGetFunction (Local< Context > context)
 
V8_WARN_UNUSED_RESULT MaybeLocal< ObjectNewRemoteInstance ()
 
void SetCallHandler (FunctionCallback callback, Local< Value > data=Local< Value >(), experimental::FastAccessorBuilder *fast_handler=nullptr)
 
void SetLength (int length)
 
Local< ObjectTemplateInstanceTemplate ()
 
void Inherit (Local< FunctionTemplate > parent)
 
Local< ObjectTemplatePrototypeTemplate ()
 
void SetPrototypeProviderTemplate (Local< FunctionTemplate > prototype_provider)
 
void SetClassName (Local< String > name)
 
void SetAcceptAnyReceiver (bool value)
 
void SetHiddenPrototype (bool value)
 
void ReadOnlyPrototype ()
 
void RemovePrototype ()
 
bool HasInstance (Local< Value > object)
 
- Public Member Functions inherited from Template
void Set (Local< Name > name, Local< Data > value, PropertyAttribute attributes=None)
 
void SetPrivate (Local< Private > name, Local< Data > value, PropertyAttribute attributes=None)
 
V8_INLINE void Set (Isolate *isolate, const char *name, Local< Data > value)
 
void SetAccessorProperty (Local< Name > name, Local< FunctionTemplate > getter=Local< FunctionTemplate >(), Local< FunctionTemplate > setter=Local< FunctionTemplate >(), PropertyAttribute attribute=None, AccessControl settings=DEFAULT)
 
void SetNativeDataProperty (Local< String > name, AccessorGetterCallback getter, AccessorSetterCallback setter=0, Local< Value > data=Local< Value >(), PropertyAttribute attribute=None, Local< AccessorSignature > signature=Local< AccessorSignature >(), AccessControl settings=DEFAULT)
 
void SetNativeDataProperty (Local< Name > name, AccessorNameGetterCallback getter, AccessorNameSetterCallback setter=0, Local< Value > data=Local< Value >(), PropertyAttribute attribute=None, Local< AccessorSignature > signature=Local< AccessorSignature >(), AccessControl settings=DEFAULT)
 
void SetLazyDataProperty (Local< Name > name, AccessorNameGetterCallback getter, Local< Value > data=Local< Value >(), PropertyAttribute attribute=None)
 
void SetIntrinsicDataProperty (Local< Name > name, Intrinsic intrinsic, PropertyAttribute attribute=None)
 

Static Public Member Functions

static Local< FunctionTemplateNew (Isolate *isolate, FunctionCallback callback=0, Local< Value > data=Local< Value >(), Local< Signature > signature=Local< Signature >(), int length=0, ConstructorBehavior behavior=ConstructorBehavior::kAllow)
 
static MaybeLocal< FunctionTemplateFromSnapshot (Isolate *isolate, size_t index)
 
static Local< FunctionTemplateNewWithFastHandler (Isolate *isolate, FunctionCallback callback, experimental::FastAccessorBuilder *fast_handler=nullptr, Local< Value > data=Local< Value >(), Local< Signature > signature=Local< Signature >(), int length=0)
 
static Local< FunctionTemplateNewWithCache (Isolate *isolate, FunctionCallback callback, Local< Private > cache_property, Local< Value > data=Local< Value >(), Local< Signature > signature=Local< Signature >(), int length=0)
 

Friends

class Context
 
class ObjectTemplate
 

Detailed Description

A FunctionTemplate is used to create functions at runtime. There can only be one function created from a FunctionTemplate in a context. The lifetime of the created function is equal to the lifetime of the context. So in case the embedder needs to create temporary functions that can be collected using Scripts is preferred.

Any modification of a FunctionTemplate after first instantiation will trigger a crash.

A FunctionTemplate can have properties, these properties are added to the function object when it is created.

A FunctionTemplate has a corresponding instance template which is used to create object instances when the function is used as a constructor. Properties added to the instance template are added to each object instance.

A FunctionTemplate can have a prototype template. The prototype template is used to create the prototype object of the function.

The following example shows how to use a FunctionTemplate:

t->Set(isolate, "func_property", v8::Number::New(isolate, 1));
proto_t->Set(isolate,
"proto_method",
v8::FunctionTemplate::New(isolate, InvokeCallback));
proto_t->Set(isolate, "proto_const", v8::Number::New(isolate, 2));
instance_t->SetAccessor(String::NewFromUtf8(isolate, "instance_accessor"),
InstanceAccessorCallback);
instance_t->SetNamedPropertyHandler(PropertyHandlerCallback);
instance_t->Set(String::NewFromUtf8(isolate, "instance_property"),
Number::New(isolate, 3));
v8::Local<v8::Object> instance = function->NewInstance();

Let's use "function" as the JS variable name of the function object and "instance" for the instance object created above. The function and the instance will have the following properties:

func_property in function == true;
function.func_property == 1;
function.prototype.proto_method() invokes 'InvokeCallback'
function.prototype.proto_const == 2;
instance instanceof function == true;
instance.instance_accessor calls 'InstanceAccessorCallback'
instance.instance_property == 3;

A FunctionTemplate can inherit from another one by calling the FunctionTemplate::Inherit method. The following graph illustrates the semantics of inheritance:

FunctionTemplate Parent -> Parent() . prototype -> { }
^ ^
| Inherit(Parent) | .__proto__
| |
FunctionTemplate Child -> Child() . prototype -> { }

A FunctionTemplate 'Child' inherits from 'Parent', the prototype object of the Child() function has proto pointing to the Parent() function's prototype object. An instance of the Child function has all properties on Parent's instance templates.

Let Parent be the FunctionTemplate initialized in the previous section and create a Child FunctionTemplate by:

Local<FunctionTemplate> parent = t;
Local<FunctionTemplate> child = FunctionTemplate::New();
child->Inherit(parent);
Local<Function> child_function = child->GetFunction();
Local<Object> child_instance = child_function->NewInstance();

The Child function and Child instance will have the following properties:

child_func.prototype.__proto__ == function.prototype;
child_instance.instance_accessor calls 'InstanceAccessorCallback'
child_instance.instance_property == 3;

Definition at line 5112 of file v8.h.

Member Function Documentation

static MaybeLocal<FunctionTemplate> FromSnapshot ( Isolate isolate,
size_t  index 
)
static

Get a template included in the snapshot by index.

V8_WARN_UNUSED_RESULT MaybeLocal<Function> GetFunction ( Local< Context context)
bool HasInstance ( Local< Value object)

Returns true if the given object is an instance of this function template.

void Inherit ( Local< FunctionTemplate parent)

Causes the function template to inherit from a parent function template. This means the the function's prototype.__proto__ is set to the parent function's prototype.

Local<ObjectTemplate> InstanceTemplate ( )

Get the InstanceTemplate.

static Local<FunctionTemplate> New ( Isolate isolate,
FunctionCallback  callback = 0,
Local< Value data = LocalValue >(),
Local< Signature signature = LocalSignature >(),
int  length = 0,
ConstructorBehavior  behavior = ConstructorBehavior::kAllow 
)
static

Creates a function template.

V8_WARN_UNUSED_RESULT MaybeLocal<Object> NewRemoteInstance ( )

Similar to Context::NewRemoteContext, this creates an instance that isn't backed by an actual object.

The InstanceTemplate of this FunctionTemplate must have access checks with handlers installed.

static Local<FunctionTemplate> NewWithCache ( Isolate isolate,
FunctionCallback  callback,
Local< Private cache_property,
Local< Value data = LocalValue >(),
Local< Signature signature = LocalSignature >(),
int  length = 0 
)
static

Creates a function template backed/cached by a private property.

static Local<FunctionTemplate> NewWithFastHandler ( Isolate isolate,
FunctionCallback  callback,
experimental::FastAccessorBuilder fast_handler = nullptr,
Local< Value data = LocalValue >(),
Local< Signature signature = LocalSignature >(),
int  length = 0 
)
static

Creates a function template with a fast handler. If a fast handler is set, the callback cannot be null.

Local<ObjectTemplate> PrototypeTemplate ( )

A PrototypeTemplate is the template used to create the prototype object of the function created by this template.

void ReadOnlyPrototype ( )

Sets the ReadOnly flag in the attributes of the 'prototype' property of functions created from this FunctionTemplate to true.

void RemovePrototype ( )

Removes the prototype property from functions created from this FunctionTemplate.

void SetAcceptAnyReceiver ( bool  value)

When set to true, no access check will be performed on the receiver of a function call. Currently defaults to true, but this is subject to change.

void SetCallHandler ( FunctionCallback  callback,
Local< Value data = LocalValue >(),
experimental::FastAccessorBuilder fast_handler = nullptr 
)

Set the call-handler callback for a FunctionTemplate. This callback is called whenever the function created from this FunctionTemplate is called.

void SetClassName ( Local< String name)

Set the class name of the FunctionTemplate. This is used for printing objects created with the function created from the FunctionTemplate as its constructor.

void SetHiddenPrototype ( bool  value)

Determines whether the proto accessor ignores instances of the function template. If instances of the function template are ignored, proto skips all instances and instead returns the next object in the prototype chain.

Call with a value of true to make the proto accessor ignore instances of the function template. Call with a value of false to make the proto accessor not ignore instances of the function template. By default, instances of a function template are not ignored.

void SetLength ( int  length)

Set the predefined length property for the FunctionTemplate.

void SetPrototypeProviderTemplate ( Local< FunctionTemplate prototype_provider)

A PrototypeProviderTemplate is another function template whose prototype property is used for this template. This is mutually exclusive with setting a prototype template indirectly by calling PrototypeTemplate() or using Inherit().

V8_DEPRECATE_SOON ( "Use maybe version"  ,
Local< Function >   GetFunction() 
)

Returns the unique function instance in the current execution context.

Friends And Related Function Documentation

friend class Context
friend

Definition at line 5241 of file v8.h.

friend class ObjectTemplate
friend

Definition at line 5242 of file v8.h.


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