(void)mProvider->GetFile(*mCurrentKey++, &dontCare, getter_AddRefs(mNext));
nsCOMPtr<nsIFile> testFile; (void)mProvider->GetFile(*mCurrentKey++, &dontCare, getter_AddRefs(testFile));  PRBool exists; if (testFile && NS_SUCCEEDED(testFile->Exists(&exists)) && exists) mNext = testFile;
    NS_IMETHOD HasMoreElements(PRBool *result)     {        while (!mNext && *mCurrentKey)        {            PRBool dontCare;            (void)mProvider->GetFile(*mCurrentKey++, &dontCare, getter_AddRefs(mNext));        }        *result = mNext != nsnull;        return NS_OK;    }