v8::FunctionTemplate Class Reference

#include <v8-template.h>

Inheritance diagram for v8::FunctionTemplate:

Collaboration diagram for v8::FunctionTemplate:

Public Member Functions
MaybeLocal< Function >	GetFunction (Local< Context > context)
MaybeLocal< Object >	NewRemoteInstance ()
void	SetCallHandler (FunctionCallback callback, Local< Value > data=Local< Value >(), SideEffectType side_effect_type=SideEffectType::kHasSideEffect, const MemorySpan< const CFunction > &c_function_overloads={})
void	SetLength (int length)
Local< ObjectTemplate >	InstanceTemplate ()
void	Inherit (Local< FunctionTemplate > parent)
Local< ObjectTemplate >	PrototypeTemplate ()
void	SetPrototypeProviderTemplate (Local< FunctionTemplate > prototype_provider)
void	SetClassName (Local< String > name)
void	SetInterfaceName (Local< String > name)
void	SetExceptionContext (ExceptionContext context)
void	SetAcceptAnyReceiver (bool value)
void	ReadOnlyPrototype ()
void	RemovePrototype ()
bool	HasInstance (Local< Value > object)
bool	IsLeafTemplateForApiObject (v8::Local< v8::Value > value) const
Public Member Functions inherited from v8::Template
void	Set (Local< Name > name, Local< Data > value, PropertyAttribute attributes=None)
void	SetPrivate (Local< Private > name, Local< Data > value, PropertyAttribute attributes=None)
void	Set (Isolate *isolate, const char *name, Local< Data > value, PropertyAttribute attributes=None)
void	SetAccessorProperty (Local< Name > name, Local< FunctionTemplate > getter=Local< FunctionTemplate >(), Local< FunctionTemplate > setter=Local< FunctionTemplate >(), PropertyAttribute attribute=None)
void	SetNativeDataProperty (Local< Name > name, AccessorNameGetterCallback getter, AccessorNameSetterCallback setter=nullptr, Local< Value > data=Local< Value >(), PropertyAttribute attribute=None, SideEffectType getter_side_effect_type=SideEffectType::kHasSideEffect, SideEffectType setter_side_effect_type=SideEffectType::kHasSideEffect)
void	SetLazyDataProperty (Local< Name > name, AccessorNameGetterCallback getter, Local< Value > data=Local< Value >(), PropertyAttribute attribute=None, SideEffectType getter_side_effect_type=SideEffectType::kHasSideEffect, SideEffectType setter_side_effect_type=SideEffectType::kHasSideEffect)
void	SetIntrinsicDataProperty (Local< Name > name, Intrinsic intrinsic, PropertyAttribute attribute=None)
Public Member Functions inherited from v8::Data
bool	IsValue () const
bool	IsModule () const
bool	IsFixedArray () const
bool	IsPrivate () const
bool	IsObjectTemplate () const
bool	IsFunctionTemplate () const
bool	IsContext () const

Static Public Member Functions
static Local< FunctionTemplate >	New (Isolate *isolate, FunctionCallback callback=nullptr, Local< Value > data=Local< Value >(), Local< Signature > signature=Local< Signature >(), int length=0, ConstructorBehavior behavior=ConstructorBehavior::kAllow, SideEffectType side_effect_type=SideEffectType::kHasSideEffect, const CFunction *c_function=nullptr, uint16_t instance_type=0, uint16_t allowed_receiver_instance_type_range_start=0, uint16_t allowed_receiver_instance_type_range_end=0)
static Local< FunctionTemplate >	NewWithCFunctionOverloads (Isolate *isolate, FunctionCallback callback=nullptr, Local< Value > data=Local< Value >(), Local< Signature > signature=Local< Signature >(), int length=0, ConstructorBehavior behavior=ConstructorBehavior::kAllow, SideEffectType side_effect_type=SideEffectType::kHasSideEffect, const MemorySpan< const CFunction > &c_function_overloads={})
static Local< FunctionTemplate >	NewWithCache (Isolate *isolate, FunctionCallback callback, Local< Private > cache_property, Local< Value > data=Local< Value >(), Local< Signature > signature=Local< Signature >(), int length=0, SideEffectType side_effect_type=SideEffectType::kHasSideEffect)
static FunctionTemplate *	Cast (Data *data)

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:

v8::Local<v8::FunctionTemplate> t = v8::FunctionTemplate::New(isolate);
t->Set(isolate, "func_property", v8::Number::New(isolate, 1));
 
v8::Local<v8::Template> proto_t = t->PrototypeTemplate();
proto_t->Set(isolate,
             "proto_method",
             v8::FunctionTemplate::New(isolate, InvokeCallback));
proto_t->Set(isolate, "proto_const", v8::Number::New(isolate, 2));
 
v8::Local<v8::ObjectTemplate> instance_t = t->InstanceTemplate();
instance_t->SetNativeDataProperty(
    String::NewFromUtf8Literal(isolate, "instance_accessor"),
    InstanceAccessorCallback);
instance_t->SetHandler(
    NamedPropertyHandlerConfiguration(PropertyHandlerCallback));
instance_t->Set(String::NewFromUtf8Literal(isolate, "instance_property"),
                Number::New(isolate, 3));
 
v8::Local<v8::Function> function = t->GetFunction();
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;

The additional 'c_function' parameter refers to a fast API call, which must not trigger GC or JavaScript execution, or call into V8 in other ways. For more information how to define them, see include/v8-fast-api-calls.h. Please note that this feature is still experimental.

Examples

process.cc.

Member Function Documentation

Cast()

FunctionTemplate * v8::FunctionTemplate::Cast ( Data *  data )

inlinestatic

GetFunction()

MaybeLocal< Function > v8::FunctionTemplate::GetFunction

(

Local< Context >

context

)

Returns the unique function instance in the current execution context.

HasInstance()

bool v8::FunctionTemplate::HasInstance

(

Local< Value >

object

)

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

Inherit()

void v8::FunctionTemplate::Inherit

(

Local< FunctionTemplate >

parent

)

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

InstanceTemplate()

Local< ObjectTemplate > v8::FunctionTemplate::InstanceTemplate

(

)

Get the InstanceTemplate.

IsLeafTemplateForApiObject()

bool v8::FunctionTemplate::IsLeafTemplateForApiObject

(

v8::Local< v8::Value >

value

)

const

Returns true if the given value is an API object that was constructed by an instance of this function template (without checking for inheriting function templates).

This is an experimental feature and may still change significantly.

New()

static Local< FunctionTemplate > v8::FunctionTemplate::New ( Isolate *  isolate, FunctionCallback  callback = nullptr, Local< Value >  data = Local< Value >(), Local< Signature >  signature = Local< Signature >(), int  length = 0, ConstructorBehavior  behavior = ConstructorBehavior::kAllow, SideEffectType  side_effect_type = SideEffectType::kHasSideEffect, const CFunction *  c_function = nullptr, uint16_t  instance_type = 0, uint16_t  allowed_receiver_instance_type_range_start = 0, uint16_t  allowed_receiver_instance_type_range_end = 0  )

static

Creates a function template.

Examples

shell.cc.

NewRemoteInstance()

MaybeLocal< Object > v8::FunctionTemplate::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.

NewWithCache()

static Local< FunctionTemplate > v8::FunctionTemplate::NewWithCache ( Isolate *  isolate, FunctionCallback  callback, Local< Private >  cache_property, Local< Value >  data = Local< Value >(), Local< Signature >  signature = Local< Signature >(), int  length = 0, SideEffectType  side_effect_type = SideEffectType::kHasSideEffect  )

static

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

NewWithCFunctionOverloads()

static Local< FunctionTemplate > v8::FunctionTemplate::NewWithCFunctionOverloads ( Isolate *  isolate, FunctionCallback  callback = nullptr, Local< Value >  data = Local< Value >(), Local< Signature >  signature = Local< Signature >(), int  length = 0, ConstructorBehavior  behavior = ConstructorBehavior::kAllow, SideEffectType  side_effect_type = SideEffectType::kHasSideEffect, const MemorySpan< const CFunction > &  c_function_overloads = {}  )

static

Creates a function template for multiple overloaded fast API calls.

PrototypeTemplate()

Local< ObjectTemplate > v8::FunctionTemplate::PrototypeTemplate

(

)

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

ReadOnlyPrototype()

void v8::FunctionTemplate::ReadOnlyPrototype

(

)

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

RemovePrototype()

void v8::FunctionTemplate::RemovePrototype

(

)

Removes the prototype property from functions created from this FunctionTemplate.

SetAcceptAnyReceiver()

void v8::FunctionTemplate::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.

SetCallHandler()

void v8::FunctionTemplate::SetCallHandler	(	FunctionCallback	callback,
		Local< Value >	data = Local< Value >(),
		SideEffectType	side_effect_type = SideEffectType::kHasSideEffect,
		const MemorySpan< const CFunction > &	c_function_overloads = {}
	)

Set the call-handler callback for a FunctionTemplate. This callback is called whenever the function created from this FunctionTemplate is called. The 'c_function' represents a fast API call, see the comment above the class declaration.

SetClassName()

void v8::FunctionTemplate::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.

SetExceptionContext()

void v8::FunctionTemplate::SetExceptionContext

(

ExceptionContext

context

)

Provides information on the type of FunctionTemplate for embedder exception handling.

SetInterfaceName()

void v8::FunctionTemplate::SetInterfaceName

(

Local< String >

name

)

Set the interface name of the FunctionTemplate. This is provided as contextual information in an ExceptionPropagationMessage to the embedder.

SetLength()

void v8::FunctionTemplate::SetLength

(

int

length

)

Set the predefined length property for the FunctionTemplate.

SetPrototypeProviderTemplate()

void v8::FunctionTemplate::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().

Friends And Related Function Documentation

Context

friend class Context

friend

ObjectTemplate

friend class ObjectTemplate

friend

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

• include/v8-template.h