JSExtendedClass 编辑

Obsolete since JavaScript 1.8.5
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

JSExtendedClass is an extended version of JSClass with additional hooks.

A C/C++ program can use a JSExtendedClass with the JS_InitClass and JS_NewObject APIs to create objects that have custom methods and properties implemented in C/C++.

Syntax

struct JSExtendedClass {
   JSClass             base;
   JSEqualityOp        equality;
   JSObjectOp          outerObject;
   JSObjectOp          innerObject;
   JSIteratorOp        iteratorObject;// Added in SpiderMonkey 1.8
   JSObjectOp          wrappedObject; // Added in SpiderMonkey 1.8

   ...and additional reserved fields.
};

Description

To implement a custom class that uses any of the JSExtendedClass callbacks:

• Create a JSExtendedClass and populate both the base fields and the extended fields.
• Ensure that the additional reserved fields at the end of the JSExtendedClass are NULL. JSClass and JSExtendedClass structs should usually be global, and in this case the compiler automatically initializes these fields to NULL. (This is a feature of the C and C++ languages.) Otherwise, use memset.
• Set the JSCLASS_IS_EXTENDED flag in myExtendedClass.base.flags.
• Pass &myExtendedClass.base to functions like JS_InitClass or JS_NewObject that require a JSClass *.

See Also

• bug 571789