feat(xep): Allow negotiating SM enabling inline with Bind2

packages/moxxmpp/lib/src/negotiators/sasl2.dart

@@ -218,6 +218,7 @@ class Sasl2Negotiator extends XmppFeatureNegotiatorBase {
         attributes.sendNonza(authenticate);
         return const Result(NegotiatorState.ready);
       case Sasl2State.authenticateSent:
+        // TODO(PapaTutuWawa): Handle failure
         if (nonza.tag == 'success') {
           // Tell the dependent negotiators about the result
           final negotiators = _featureNegotiators

packages/moxxmpp/lib/src/xeps/xep_0198/negotiator.dart

@@ -12,6 +12,7 @@ import 'package:moxxmpp/src/xeps/xep_0198/nonzas.dart';
 import 'package:moxxmpp/src/xeps/xep_0198/state.dart';
 import 'package:moxxmpp/src/xeps/xep_0198/xep_0198.dart';
 import 'package:moxxmpp/src/xeps/xep_0352.dart';
+import 'package:moxxmpp/src/xeps/xep_0386.dart';
 
 enum _StreamManagementNegotiatorState {
   // We have not done anything yet
@@ -25,7 +26,8 @@ enum _StreamManagementNegotiatorState {
 /// NOTE: The stream management negotiator requires that loadState has been called on the
 ///       StreamManagementManager at least once before connecting, if stream resumption
 ///       is wanted.
-class StreamManagementNegotiator extends Sasl2FeatureNegotiator {
+class StreamManagementNegotiator extends Sasl2FeatureNegotiator
+    implements Bind2FeatureNegotiator {
   StreamManagementNegotiator()
       : super(10, false, smXmlns, streamManagementNegotiator);
 
@@ -200,6 +202,22 @@ class StreamManagementNegotiator extends Sasl2FeatureNegotiator {
     super.reset();
   }
 
+  @override
+  Future<List<XMLNode>> onBind2FeaturesReceived(
+    List<String> bind2Features,
+  ) async {
+    if (!bind2Features.contains(smXmlns)) {
+      return [];
+    }
+
+    return [
+      XMLNode.xmlns(
+        tag: 'enable',
+        xmlns: smXmlns,
+      ),
+    ];
+  }
+
   @override
   Future<List<XMLNode>> onSasl2FeaturesReceived(XMLNode sasl2Features) async {
     final inline = sasl2Features.firstTag('inline')!;
@@ -231,6 +249,7 @@ class StreamManagementNegotiator extends Sasl2FeatureNegotiator {
 
   @override
   Future<Result<bool, NegotiatorError>> onSasl2Success(XMLNode response) async {
+    // TODO(PapaTutuWawa): Handle SM failures.
     final resumed = response.firstTag('resumed', xmlns: smXmlns);
     if (resumed == null) {
       _log.warning('Inline stream resumption failed');
@@ -254,5 +273,8 @@ class StreamManagementNegotiator extends Sasl2FeatureNegotiator {
     attributes
         .getNegotiatorById<Sasl2Negotiator>(sasl2Negotiator)
         ?.registerNegotiator(this);
+    attributes
+        .getNegotiatorById<Bind2Negotiator>(bind2Negotiator)
+        ?.registerNegotiator(this);
   }
 }

packages/moxxmpp/lib/src/xeps/xep_0386.dart

@@ -6,14 +6,33 @@ import 'package:moxxmpp/src/negotiators/sasl2.dart';
 import 'package:moxxmpp/src/stringxml.dart';
 import 'package:moxxmpp/src/types/result.dart';
 
+/// An interface that allows registering against Bind2's feature list in order to
+/// negotiate features inline with Bind2.
+// ignore: one_member_abstracts
+abstract class Bind2FeatureNegotiator {
+  /// Called by the Bind2 negotiator when Bind2 features are received. The returned
+  /// [XMLNode]s are added to Bind2's bind request.
+  Future<List<XMLNode>> onBind2FeaturesReceived(List<String> bind2Features);
+}
+
 /// A negotiator implementing XEP-0386. This negotiator is useless on its own
 /// and requires a [Sasl2Negotiator] to be registered.
 class Bind2Negotiator extends Sasl2FeatureNegotiator {
   Bind2Negotiator() : super(0, false, bind2Xmlns, bind2Negotiator);
 
+  /// A list of negotiators that can work with Bind2.
+  final List<Bind2FeatureNegotiator> _negotiators =
+      List<Bind2FeatureNegotiator>.empty(growable: true);
+
   /// A tag to sent to the server when requesting Bind2.
   String? tag;
 
+  /// Register [negotiator] against the Bind2 negotiator to append data to the Bind2
+  /// negotiation.
+  void registerNegotiator(Bind2FeatureNegotiator negotiator) {
+    _negotiators.add(negotiator);
+  }
+
   @override
   Future<Result<NegotiatorState, NegotiatorError>> negotiate(
     XMLNode nonza,
@@ -23,6 +42,25 @@ class Bind2Negotiator extends Sasl2FeatureNegotiator {
 
   @override
   Future<List<XMLNode>> onSasl2FeaturesReceived(XMLNode sasl2Features) async {
+    final children = List<XMLNode>.empty(growable: true);
+    if (_negotiators.isNotEmpty) {
+      final inline = sasl2Features
+          .firstTag('inline')!
+          .firstTag('bind', xmlns: bind2Xmlns)!
+          .firstTag('inline');
+      if (inline != null) {
+        final features = inline.children
+            .where((child) => child.tag == 'feature')
+            .map((child) => child.attributes['var']! as String)
+            .toList();
+
+        // Only call the negotiators if Bind2 allows doing stuff inline
+        for (final negotiator in _negotiators) {
+          children.addAll(await negotiator.onBind2FeaturesReceived(features));
+        }
+      }
+    }
+
     return [
       XMLNode.xmlns(
         tag: 'bind',
@@ -33,6 +71,7 @@ class Bind2Negotiator extends Sasl2FeatureNegotiator {
               tag: 'tag',
               text: tag,
             ),
+          ...children,
         ],
       ),
     ];

packages/moxxmpp/test/xeps/xep_0198_test.dart

@@ -882,4 +882,104 @@ void main() {
     );
     expect(conn.resource, 'test-resource');
   });
+
+  test('Test SASL2 inline stream resumption with Bind2', () async {
+    final fakeSocket = StubTCPSocket([
+      StringExpectation(
+        "<stream:stream xmlns='jabber:client' version='1.0' xmlns:stream='http://etherx.jabber.org/streams' to='test.server' xml:lang='en'>",
+        '''
+<stream:stream
+    xmlns="jabber:client"
+    version="1.0"
+    xmlns:stream="http://etherx.jabber.org/streams"
+    from="test.server"
+    xml:lang="en">
+  <stream:features xmlns="http://etherx.jabber.org/streams">
+    <mechanisms xmlns="urn:ietf:params:xml:ns:xmpp-sasl">
+      <mechanism>PLAIN</mechanism>
+    </mechanisms>
+    <authentication xmlns='urn:xmpp:sasl:2'>
+      <mechanism>PLAIN</mechanism>
+      <inline>
+        <resume xmlns="urn:xmpp:sm:3" />
+        <bind xmlns="urn:xmpp:bind:0">
+          <inline>
+            <feature var="urn:xmpp:sm:3" />
+          </inline>
+        </bind>
+      </inline>
+    </authentication>
+    <bind xmlns="urn:ietf:params:xml:ns:xmpp-bind">
+      <required/>
+    </bind>
+  </stream:features>''',
+      ),
+      StanzaExpectation(
+        "<authenticate xmlns='urn:xmpp:sasl:2' mechanism='PLAIN'><user-agent id='d4565fa7-4d72-4749-b3d3-740edbf87770'><software>moxxmpp</software><device>PapaTutuWawa's awesome device</device></user-agent><initial-response>AHBvbHlub21kaXZpc2lvbgBhYWFh</initial-response><bind xmlns='urn:xmpp:bind:0'><enable xmlns='urn:xmpp:sm:3' /></bind><resume xmlns='urn:xmpp:sm:3' previd='test-prev-id' h='2' /></authenticate>",
+        '''
+<success xmlns='urn:xmpp:sasl:2'>
+  <authorization-identifier>polynomdivision@test.server</authorization-identifier>
+  <resumed xmlns='urn:xmpp:sm:3' h='25' previd='test-prev-id' />
+</success>
+        ''',
+      ),
+    ]);
+    final sm = StreamManagementManager();
+    await sm.setState(
+      sm.state.copyWith(
+        c2s: 25,
+        s2c: 2,
+        streamResumptionId: 'test-prev-id',
+      ),
+    );
+
+    final conn = XmppConnection(
+      TestingReconnectionPolicy(),
+      AlwaysConnectedConnectivityManager(),
+      fakeSocket,
+    )
+      ..setConnectionSettings(
+        ConnectionSettings(
+          jid: JID.fromString('polynomdivision@test.server'),
+          password: 'aaaa',
+          useDirectTLS: true,
+        ),
+      )
+      ..setResource('test-resource', triggerEvent: false);
+    await conn.registerManagers([
+      RosterManager(TestingRosterStateManager('', [])),
+      DiscoManager([]),
+      sm,
+    ]);
+    await conn.registerFeatureNegotiators([
+      SaslPlainNegotiator(),
+      ResourceBindingNegotiator(),
+      StreamManagementNegotiator(),
+      Bind2Negotiator(),
+      Sasl2Negotiator(
+        userAgent: const UserAgent(
+          id: 'd4565fa7-4d72-4749-b3d3-740edbf87770',
+          software: 'moxxmpp',
+          device: "PapaTutuWawa's awesome device",
+        ),
+      ),
+    ]);
+
+    final result = await conn.connect(
+      waitUntilLogin: true,
+      shouldReconnect: false,
+      enableReconnectOnSuccess: false,
+    );
+    expect(result.isType<NegotiatorError>(), false);
+
+    expect(
+      sm.state.c2s,
+      25,
+    );
+    expect(
+      sm.state.s2c,
+      2,
+    );
+    expect(conn.resource, 'test-resource');
+  });
 }