if (! mURL) return NS_ERROR_NOT_INITIALIZED;
nsresult rv;
RDFXMLDataSourceImpl::Flush(void){    if (!mIsWritable || !mIsDirty)        return NS_OK;    // while it is not fatal if mURL is not set,    // indicate failure since we can't flush back to an unknown origin    if (! mURL)        return NS_ERROR_NOT_INITIALIZED;#ifdef PR_LOGGING    nsCAutoString spec;    mURL->GetSpec(spec);    PR_LOG(gLog, PR_LOG_ALWAYS,           ("rdfxml[%p] flush(%s)", this, spec.get()));#endif    nsresult rv;    if (NS_SUCCEEDED(rv = rdfXMLFlush(mURL)))    {      mIsDirty = PR_FALSE;    }    return rv;}