Subj : Re: Spidermonkey: parameters to 'construction' function
To   : Peter Paulus
From : Brendan Eich
Date : Mon Apr 19 2004 10:57 am

Peter Paulus wrote:

> This means the 'constructor' function boilerplate may look like this.
> 
> JSBool Document::createDocument(JSContext* context, JSObject* object, 
> uintN argc, jsval* argv, jsval* result)
> {
> JSBool ok = JS_FALSE;
> 
> JSObject* jsDocument = 0L;
> if (JS_IsConstructing(context))
>   {
>   jsDocument = JSVAL_TO_OBJECT(*result);  // or jsDocument = object;


You could use |obj| instead of |*result| here -- it's faster and it is 
better documented, as well as being to my mind nicer looking.  Either 
way works and will continue to work, though, so it's your choice.


>   }
> else
>   {
>   jsDocument = JS_NewObject(context, &Document::clazz, NULL, NULL);


Check for null return, if so, return JS_FALSE immediately to propagate 
the out-of-memory error.


>   *result = OBJECT_TO_JSVAL(jsDocument);
>   }
> 
> if (jsDocument)


No need for this test if you return early on null.


>   {
>   void* hostDocument = new ...;
>   ok = JS_SetPrivate(context, jsDocument, hostDocument);


And that allows you to return JS_SetPrivate(...); here, eliminating the 
useless |ok| local variable.

/be

.