JSClassDefinition Struct Reference

#include <JavaScriptCore/JSObjectRef.h>

Details

This structure contains properties and callbacks that define a type of object. All fields other than the version field are optional. Any pointer may be NULL.

• version The version number of this structure. The current version is 0.
• attributes A logically ORed set of JSClassAttributes to give to the class.
• className A null-terminated UTF8 string containing the class's name.
• parentClass A JSClass to set as the class's parent class. Pass NULL use the default object class.
• staticValues A JSStaticValue array containing the class's statically declared value properties. Pass NULL to specify no statically declared value properties. The array must be terminated by a JSStaticValue whose name field is NULL.
• staticFunctions A JSStaticFunction array containing the class's statically declared function properties. Pass NULL to specify no statically declared function properties. The array must be terminated by a JSStaticFunction whose name field is NULL.
• initialize The callback invoked when an object is first created. Use this callback to initialize the object.
• finalize The callback invoked when an object is finalized (prepared for garbage collection). Use this callback to release resources allocated for the object, and perform other cleanup.
• hasProperty The callback invoked when determining whether an object has a property. If this field is NULL, getProperty is called instead. The hasProperty callback enables optimization in cases where only a property's existence needs to be known, not its value, and computing its value is expensive.
• getProperty The callback invoked when getting a property's value.
• setProperty The callback invoked when setting a property's value.
• deleteProperty The callback invoked when deleting a property.
• getPropertyNames The callback invoked when collecting the names of an object's properties.
• callAsFunction The callback invoked when an object is called as a function.
• hasInstance The callback invoked when an object is used as the target of an 'instanceof' expression.
• callAsConstructor The callback invoked when an object is used as a constructor in a 'new' expression.
• convertToType The callback invoked when converting an object to a particular JavaScript type.

  Note

  The staticValues and staticFunctions arrays are the simplest and most efficient means for vending custom properties. Statically declared properties autmatically service requests like getProperty, setProperty, and getPropertyNames. Property access callbacks are required only to implement unusual properties, like array indexes, whose names are not known at compile-time.

  If you named your getter function "GetX" and your setter function "SetX", you would declare a JSStaticValue array containing "X" like this:

  JSStaticValue StaticValueArray[] = { { "X", GetX, SetX, kJSPropertyAttributeNone }, { 0, 0, 0, 0 } };

  Standard JavaScript practice calls for storing function objects in prototypes, so they can be shared. The default JSClass created by JSClassCreate follows this idiom, instantiating objects with a shared, automatically generating prototype containing the class's function objects. The kJSClassAttributeNoAutomaticPrototype attribute specifies that a JSClass should not automatically generate such a prototype. The resulting JSClass instantiates objects with the default object prototype, and gives each instance object its own copy of the class's function objects.

  A NULL callback specifies that the default object callback should substitute, except in the case of hasProperty, where it specifies that getProperty should substitute.

Data Fields
int	version
JSClassAttributes	attributes
const char *	className
JSClassRef	parentClass
union {
struct {
const JSStaticValue *   staticValues
const JSStaticFunction *   staticFunctions
JSObjectInitializeCallback   initialize
JSObjectFinalizeCallback   finalize
JSObjectHasPropertyCallback   hasProperty
JSObjectGetPropertyCallback   getProperty
JSObjectSetPropertyCallback   setProperty
JSObjectDeletePropertyCallback   deleteProperty
JSObjectGetPropertyNamesCallback   getPropertyNames
JSObjectCallAsFunctionCallback   callAsFunction
JSObjectCallAsConstructorCallback   callAsConstructor
JSObjectHasInstanceCallback   hasInstance
JSObjectConvertToTypeCallback   convertToType
}
struct {
const JSStaticValueEx *   staticValuesEx
const JSStaticFunctionEx *   staticFunctionsEx
JSObjectInitializeCallbackEx   initializeEx
JSObjectFinalizeCallbackEx   finalizeEx
JSObjectHasPropertyCallbackEx   hasPropertyEx
JSObjectGetPropertyCallbackEx   getPropertyEx
JSObjectSetPropertyCallbackEx   setPropertyEx
JSObjectDeletePropertyCallbackEx   deletePropertyEx
JSObjectGetPropertyNamesCallbackEx   getPropertyNamesEx
JSObjectCallAsFunctionCallbackEx   callAsFunctionEx
JSObjectCallAsConstructorCallbackEx   callAsConstructorEx
JSObjectHasInstanceCallbackEx   hasInstanceEx
JSObjectConvertToTypeCallbackEx   convertToTypeEx
}
};
void *	privateData

Field Documentation

[union]

union { ... } JSClassDefinition

attributes

JSClassAttributes JSClassDefinition::attributes

callAsConstructor

JSObjectCallAsConstructorCallback JSClassDefinition::callAsConstructor

callAsConstructorEx

JSObjectCallAsConstructorCallbackEx JSClassDefinition::callAsConstructorEx

callAsFunction

JSObjectCallAsFunctionCallback JSClassDefinition::callAsFunction

callAsFunctionEx

JSObjectCallAsFunctionCallbackEx JSClassDefinition::callAsFunctionEx

className

const char* JSClassDefinition::className

convertToType

JSObjectConvertToTypeCallback JSClassDefinition::convertToType

convertToTypeEx

JSObjectConvertToTypeCallbackEx JSClassDefinition::convertToTypeEx

deleteProperty

JSObjectDeletePropertyCallback JSClassDefinition::deleteProperty

deletePropertyEx

JSObjectDeletePropertyCallbackEx JSClassDefinition::deletePropertyEx

finalize

JSObjectFinalizeCallback JSClassDefinition::finalize

finalizeEx

JSObjectFinalizeCallbackEx JSClassDefinition::finalizeEx

getProperty

JSObjectGetPropertyCallback JSClassDefinition::getProperty

getPropertyEx

JSObjectGetPropertyCallbackEx JSClassDefinition::getPropertyEx

getPropertyNames

JSObjectGetPropertyNamesCallback JSClassDefinition::getPropertyNames

getPropertyNamesEx

JSObjectGetPropertyNamesCallbackEx JSClassDefinition::getPropertyNamesEx

hasInstance

JSObjectHasInstanceCallback JSClassDefinition::hasInstance

hasInstanceEx

JSObjectHasInstanceCallbackEx JSClassDefinition::hasInstanceEx

hasProperty

JSObjectHasPropertyCallback JSClassDefinition::hasProperty

hasPropertyEx

JSObjectHasPropertyCallbackEx JSClassDefinition::hasPropertyEx

initialize

JSObjectInitializeCallback JSClassDefinition::initialize

initializeEx

JSObjectInitializeCallbackEx JSClassDefinition::initializeEx

parentClass

JSClassRef JSClassDefinition::parentClass

privateData

void* JSClassDefinition::privateData

setProperty

JSObjectSetPropertyCallback JSClassDefinition::setProperty

setPropertyEx

JSObjectSetPropertyCallbackEx JSClassDefinition::setPropertyEx

staticFunctions

const JSStaticFunction* JSClassDefinition::staticFunctions

staticFunctionsEx

const JSStaticFunctionEx* JSClassDefinition::staticFunctionsEx

staticValues

const JSStaticValue* JSClassDefinition::staticValues

staticValuesEx

const JSStaticValueEx* JSClassDefinition::staticValuesEx

version

int JSClassDefinition::version

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

• JavaScriptCore/JSObjectRef.h