Improve code using new xmpp API

rebar.config

@@ -24,8 +24,8 @@
         {cache_tab, ".*", {git, "https://github.com/processone/cache_tab", {tag, "1.0.12"}}},
         {fast_tls, ".*", {git, "https://github.com/processone/fast_tls", {tag, "1.0.17"}}},
         {stringprep, ".*", {git, "https://github.com/processone/stringprep", {tag, "1.0.10"}}},
-        {fast_xml, ".*", {git, "https://github.com/processone/fast_xml", {tag, "1.1.25"}}},
+        {fast_xml, ".*", {git, "https://github.com/processone/fast_xml", "724ec0a"}},
-        {xmpp, ".*", {git, "https://github.com/processone/xmpp", "a893ee1"}},
+        {xmpp, ".*", {git, "https://github.com/processone/xmpp", "dbbaed4edfc"}},
         {fast_yaml, ".*", {git, "https://github.com/processone/fast_yaml", {tag, "1.0.12"}}},
         {jiffy, ".*", {git, "https://github.com/davisp/jiffy", {tag, "0.14.8"}}},
         {p1_oauth2, ".*", {git, "https://github.com/processone/p1_oauth2", {tag, "0.6.2"}}},

src/mod_mix.erl

@@ -310,11 +310,8 @@ is_item_not_found({error, #stanza_error{reason = 'item-not-found'}}) -> true;
 is_item_not_found({error, _}) -> false.
 
 -spec is_not_subscribed({error, stanza_error()}) -> boolean().
-is_not_subscribed({error, #stanza_error{sub_els = Els}}) ->
+is_not_subscribed({error, StanzaError}) ->
-    %% TODO: make xmpp:get_els function working for any XMPP element
+    xmpp:has_subtag(StanzaError, #ps_error{type = 'not-subscribed'}).
-    %% with sub_els field
-    xmpp:has_subtag(#message{sub_els = Els},
-		    #ps_error{type = 'not-subscribed'}).
 
 depends(_Host, _Opts) ->
     [{mod_pubsub, hard}].

src/mod_s2s_dialback.erl

@@ -334,9 +334,8 @@ mk_error(_) ->
 -spec format_error(db_result()) -> binary().
 format_error(#db_result{type = invalid}) ->
     <<"invalid dialback key">>;
-format_error(#db_result{type = error, sub_els = Els}) ->
+format_error(#db_result{type = error} = Result) ->
-    %% TODO: improve xmpp.erl
+    case xmpp:get_error(Result) of
-    case xmpp:get_error(#message{sub_els = Els}) of
 	#stanza_error{} = Err ->
 	    format_stanza_error(Err);
 	undefined ->

src/xmpp_stream_out.erl

@@ -511,7 +511,7 @@ process_features(StreamFeatures,
 	     catch _:undef -> State
 	     end,
     process_stream_established(State1);
-process_features(#stream_features{sub_els = Els} = StreamFeatures,
+process_features(StreamFeatures,
 		 #{stream_encrypted := Encrypted,
 		   mod := Mod, lang := Lang} = State) ->
     State1 = try Mod:handle_unauthenticated_features(StreamFeatures, State)
@@ -522,9 +522,7 @@ process_features(#stream_features{sub_els = Els} = StreamFeatures,
 	false ->
 	    TLSRequired = is_starttls_required(State1),
 	    TLSAvailable = is_starttls_available(State1),
-	    %% TODO: improve xmpp.erl
+	    case xmpp:get_subtag(StreamFeatures, #starttls{}) of
-	    Msg = #message{sub_els = Els},
-	    case xmpp:get_subtag(Msg, #starttls{}) of
 		false when TLSRequired and not Encrypted ->
 		    Txt = <<"Use of STARTTLS required">>,
 		    send_pkt(State1, xmpp:serr_policy_violation(Txt, Lang));
@@ -545,7 +543,7 @@ process_features(#stream_features{sub_els = Els} = StreamFeatures,
 		    case is_disconnected(State2) of
 			true -> State2;
 			false ->
-			    case xmpp:get_subtag(Msg, #sasl_mechanisms{}) of
+			    case xmpp:get_subtag(StreamFeatures, #sasl_mechanisms{}) of
 				#sasl_mechanisms{list = Mechs} ->
 				    process_sasl_mechanisms(Mechs, State2);
 				false ->