nsresult rv = NS_NewLocalFile(nsCString(), PR_FALSE, getter_AddRefs(descDir));
nsresult rv = NS_NewNativeLocalFile(nsCString(), PR_FALSE, getter_AddRefs(descDir));
CurrentAppDirMatchesPersistentDescriptor(xptiInterfaceInfoManager* aMgr,                                          const char *inStr){    nsCOMPtr<nsILocalFile> appDir;    aMgr->GetApplicationDir(getter_AddRefs(appDir));    nsCOMPtr<nsILocalFile> descDir;    nsresult rv = NS_NewLocalFile(nsCString(), PR_FALSE, getter_AddRefs(descDir));    if(NS_FAILED(rv))        return PR_FALSE;    rv = descDir->SetPersistentDescriptor(nsDependentCString(inStr));    if(NS_FAILED(rv))        return PR_FALSE;        PRBool matches;    rv = appDir->Equals(descDir, &matches);    return NS_SUCCEEDED(rv) && matches;}