Subj : Re: How to pass boolean value from C++ back to script? (jsapi)
To   : Jens Bannmann
From : Brendan Eich
Date : Mon Jan 03 2005 04:48 pm

Jens Bannmann wrote:

> Reading the boolean parameter (argv[7] here):
> |
> |   JSObject* jsObject;
> |   jsval jsCheckState;
> |   PRBool checkState = PR_FALSE;
> |
> |   if (!JSVAL_IS_NULL(argv[7])
> |       && JSVAL_IS_OBJECT(argv[7]))


Combine these into one !JSVAL_IS_PRIMITIVE(argv[7]) test.


> |     jsObject = JSVAL_TO_OBJECT(argv[7]);
> |     if (JS_GetProperty(cx, jsObject, "value", &jsCheckState)


If JS_GetProperty fails, you want to fail too.  It means an error was 
reported or an exception thrown.


> |         && JSVAL_IS_BOOLEAN(jsCheckState))
> |     {
> |       JS_ValueToBoolean(cx, jsCheckState, &checkState);


You might want to check for failure here, too, and propagate any false 
return value.


> |     }
> |   }
> 
> 
> Passing it back:
> |
> |   jsCheckState = BOOLEAN_TO_JSVAL(checkState);
> |   JS_SetProperty(cx, jsObject, "value", &jsCheckState);


Another JS API call whose return value should be checked.

/be

.