if (NS_FAILED(rv) || pPref == nsnull)
if (NS_FAILED(rv) || !pPref)
void DIR_ClearPrefBranch(const char *branch){	nsresult rv = NS_OK;	NS_WITH_SERVICE(nsIPref, pPref, kPrefCID, &rv); 	if (NS_FAILED(rv) || pPref == nsnull) 		return;	/* This little function provides a way to delete a prefs object but still	 * allow reassignment of that object later. 	 */	char *recreateBranch = nsnull;	pPref->DeleteBranch (branch);	recreateBranch = PR_smprintf("pref_inittree(\"%s\")", branch);	if (recreateBranch)	{#ifdef PREF_QuietEvaluateJSBuffer		PREF_QuietEvaluateJSBuffer (recreateBranch, PL_strlen(recreateBranch));#endif /* PREF_QuietEvaluateJSBuffer */		PR_Free(recreateBranch);	}}