fix: Make fromJson* functions work when reading JSON from a String

lib/src/double_ratchet/double_ratchet.dart

@@ -94,11 +94,20 @@ class OmemoDoubleRatchet {
       ]
     }
     */
-    final mkSkipped = <SkippedKey, List<int>>{};
-    for (final entry in data['mkskipped']! as List<Map<String, dynamic>>) {
-      final key = SkippedKey.fromJson(entry);
-      mkSkipped[key] = base64.decode(entry['key']! as String);
-    }
+    // NOTE: Dart has some issues with just casting a List<dynamic> to List<Map<...>>, as
+    //       such we need to convert the items by hand.
+    final mkSkipped = Map<SkippedKey, List<int>>.fromEntries(
+      (data['mkskipped']! as List<dynamic>).map<MapEntry<SkippedKey, List<int>>>(
+        (entry) {
+          final map = entry as Map<String, dynamic>;
+          final key = SkippedKey.fromJson(map);
+          return MapEntry(
+            key,
+            base64.decode(map['key']! as String),
+          );
+        },
+      ),
+    );
     
     return OmemoDoubleRatchet(
       OmemoKeyPair.fromBytes(

lib/src/omemo/device.dart

@@ -49,14 +49,23 @@ class Device {
       ]
     }
     */
-    final opks = <int, OmemoKeyPair>{};
-    for (final opk in data['opks']! as List<Map<String, dynamic>>) {
-      opks[opk['id']! as int] = OmemoKeyPair.fromBytes(
-        base64.decode(opk['public']! as String),
-        base64.decode(opk['private']! as String),
-        KeyPairType.x25519,
-      );
-    }
+    // NOTE: Dart has some issues with just casting a List<dynamic> to List<Map<...>>, as
+    //       such we need to convert the items by hand.
+    final opks = Map<int, OmemoKeyPair>.fromEntries(
+      (data['opks']! as List<dynamic>).map<MapEntry<int, OmemoKeyPair>>(
+        (opk) {
+          final map = opk as Map<String, dynamic>;
+          return MapEntry(
+            map['id']! as int,
+            OmemoKeyPair.fromBytes(
+              base64.decode(map['public']! as String),
+              base64.decode(map['private']! as String),
+              KeyPairType.x25519,
+            ),
+          );
+        },
+      ),
+    );
 
     return Device(
       data['jid']! as String,

lib/src/omemo/sessionmanager.dart

@@ -3,6 +3,7 @@ import 'dart:convert';
 import 'package:collection/collection.dart';
 import 'package:cryptography/cryptography.dart';
 import 'package:hex/hex.dart';
+import 'package:logging/logging.dart';
 import 'package:meta/meta.dart';
 import 'package:omemo_dart/src/crypto.dart';
 import 'package:omemo_dart/src/double_ratchet/double_ratchet.dart';
@@ -31,31 +32,28 @@ class OmemoSessionManager {
   OmemoSessionManager(this._device, this._deviceMap, this._ratchetMap, this._trustManager)
     : _lock = Lock(),
       _deviceLock = Lock(),
-      _eventStreamController = StreamController<OmemoEvent>.broadcast();
-
-  /// Deserialise the OmemoSessionManager from JSON data [data].
-  factory OmemoSessionManager.fromJson(Map<String, dynamic> data, TrustManager trustManager) {
-    final ratchetMap = <RatchetMapKey, OmemoDoubleRatchet>{};
-    for (final rawRatchet in data['sessions']! as List<Map<String, dynamic>>) {
-      final key = RatchetMapKey(rawRatchet['jid']! as String, rawRatchet['deviceId']! as int);
-      final ratchet = OmemoDoubleRatchet.fromJson(rawRatchet['ratchet']! as Map<String, dynamic>);
-      ratchetMap[key] = ratchet;
-    }
-
-    return OmemoSessionManager(
-      Device.fromJson(data['device']! as Map<String, dynamic>),
-      data['devices']! as Map<String, List<int>>,
-      ratchetMap,
-      trustManager,
-    );
-  }
+      _eventStreamController = StreamController<OmemoEvent>.broadcast(),
+      _log = Logger('OmemoSessionManager');
 
   /// Deserialise the OmemoSessionManager from JSON data [data] that does not contain
   /// the ratchet sessions.
-  factory OmemoSessionManager.fromJsonWithoutSessions(Map<String, dynamic> data, Map<RatchetMapKey, OmemoDoubleRatchet> ratchetMap, TrustManager trustManager) {
+  factory OmemoSessionManager.fromJsonWithoutSessions(
+    Map<String, dynamic> data,
+    Map<RatchetMapKey, OmemoDoubleRatchet> ratchetMap,
+    TrustManager trustManager,
+  ) {
+    // NOTE: Dart has some issues with just casting a List<dynamic> to List<Map<...>>, as
+    //       such we need to convert the items by hand.
     return OmemoSessionManager(
       Device.fromJson(data['device']! as Map<String, dynamic>),
-      data['devices']! as Map<String, List<int>>,
+      (data['devices']! as Map<String, dynamic>).map<String, List<int>>(
+        (key, value) {
+          return MapEntry(
+            key,
+            (value as List<dynamic>).map<int>((i) => i as int).toList(),
+          );
+        }
+      ),
       ratchetMap,
       trustManager,
     );
@@ -68,6 +66,9 @@ class OmemoSessionManager {
 
     return OmemoSessionManager(device, {}, {}, trustManager);
   }
+
+  /// Logging
+  Logger _log;
   
   /// Lock for _ratchetMap and _bundleMap
   final Lock _lock;
@@ -304,7 +305,7 @@ class OmemoSessionManager {
   /// [mapKey] with [oldRatchet].
   Future<void> _restoreRatchet(RatchetMapKey mapKey, OmemoDoubleRatchet oldRatchet) async {
     await _lock.synchronized(() {
-      print('RESTORING RATCHETS');
+      _log.finest('Restoring ratchet ${mapKey.jid}:${mapKey.deviceId}');
       _ratchetMap[mapKey] = oldRatchet;
 
       // Commit the ratchet
@@ -561,42 +562,6 @@ class OmemoSessionManager {
   @visibleForTesting
   Map<RatchetMapKey, OmemoDoubleRatchet> getRatchetMap() => _ratchetMap;
 
-  /// Serialise the entire session manager into a JSON object.
-  Future<Map<String, dynamic>> toJson() async {
-    /*
-    {
-      'devices': {
-        'alice@...': [1, 2, ...],
-        'bob@...': [1],
-        ...
-      },
-      'device': { ... },
-      'sessions': [
-        {
-          'jid': 'alice@...',
-          'deviceId': 1,
-          'ratchet': { ... },
-        },
-        ...
-      ],
-    }
-    */
-
-    final sessions = List<Map<String, dynamic>>.empty(growable: true);
-    for (final entry in _ratchetMap.entries) {
-      sessions.add({
-        'jid': entry.key.jid,
-        'deviceId': entry.key.deviceId,
-        'ratchet': await entry.value.toJson(),
-      });
-    }
-    return {
-      'devices': _deviceMap,
-      'device': await (await getDevice()).toJson(),
-      'sessions': sessions,
-    };
-  }
-
   /// Serialise the entire session manager into a JSON object.
   Future<Map<String, dynamic>> toJsonWithoutSessions() async {
     /*

lib/src/trust/btbv.dart

@@ -214,11 +214,6 @@ abstract class BlindTrustBeforeVerificationTrustManager extends TrustManager {
   @visibleForOverriding
   Future<void> commitState();
 
-  /// Called when the user wants to restore the state of the trust manager. The format
-  /// and actual storage mechanism is left to the user.
-  @visibleForOverriding
-  Future<void> loadState();
-  
   @visibleForTesting
   BTBVTrustState getDeviceTrust(String jid, int deviceId) => trustCache[RatchetMapKey(jid, deviceId)]!;
 }
@@ -228,7 +223,4 @@ abstract class BlindTrustBeforeVerificationTrustManager extends TrustManager {
 class MemoryBTBVTrustManager extends BlindTrustBeforeVerificationTrustManager {
   @override
   Future<void> commitState() async {}
-
-  @override
-  Future<void> loadState() async {}
 }

pubspec.yaml

@@ -11,6 +11,7 @@ dependencies:
   collection: ^1.16.0
   cryptography: ^2.0.5
   hex: ^0.2.0
+  logging: ^1.0.2
   meta: ^1.7.0
   pinenacl: ^0.5.1
   synchronized: ^3.0.0+2

test/omemo_test.dart

@@ -1,9 +1,17 @@
+import 'package:logging/logging.dart';
 import 'package:omemo_dart/omemo_dart.dart';
 import 'package:omemo_dart/src/trust/always.dart';
 import 'package:omemo_dart/src/trust/never.dart';
 import 'package:test/test.dart';
 
 void main() {
+  Logger.root
+    ..level = Level.ALL
+    ..onRecord.listen((record) {
+      // ignore: avoid_print
+      print('${record.level.name}: ${record.message}');
+    });
+
   test('Test using OMEMO sessions with only one device per user', () async {
     const aliceJid = 'alice@server.example';
     const bobJid = 'bob@other.server.example';

test/serialisation_test.dart

@@ -3,6 +3,10 @@ import 'package:omemo_dart/omemo_dart.dart';
 import 'package:omemo_dart/src/trust/always.dart';
 import 'package:test/test.dart';
 
+Map<String, dynamic> jsonify(Map<String, dynamic> map) {
+  return jsonDecode(jsonEncode(map)) as Map<String, dynamic>;
+}
+
 void main() {
   test('Test serialising and deserialising the Device', () async {
     // Generate a random session
@@ -12,7 +16,7 @@ void main() {
       opkAmount: 1,
     );
     final oldDevice = await oldSession.getDevice();
-    final serialised = await oldDevice.toJson();
+    final serialised = jsonify(await oldDevice.toJson());
 
     final newDevice = Device.fromJson(serialised);
     expect(await oldDevice.equals(newDevice), true);
@@ -26,7 +30,7 @@ void main() {
       opkAmount: 1,
     );
     final oldDevice = await (await oldSession.getDevice()).replaceSignedPrekey();
-    final serialised = await oldDevice.toJson();
+    final serialised = jsonify(await oldDevice.toJson());
 
     final newDevice = Device.fromJson(serialised);
     expect(await oldDevice.equals(newDevice), true);
@@ -60,7 +64,7 @@ void main() {
       aliceMessage.encryptedKeys,
     );
     final aliceOld = aliceSession.getRatchet(bobJid, await bobSession.getDeviceId());
-    final aliceSerialised = await aliceOld.toJson();
+    final aliceSerialised = jsonify(await aliceOld.toJson());
     final aliceNew = OmemoDoubleRatchet.fromJson(aliceSerialised);
 
     expect(await aliceOld.equals(aliceNew), true);
@@ -85,9 +89,11 @@ void main() {
     );
 
     // Serialise and deserialise
-    final serialised = await oldSession.toJson();
-    final newSession = OmemoSessionManager.fromJson(
+    final serialised = jsonify(await oldSession.toJsonWithoutSessions());
+    final newSession = OmemoSessionManager.fromJsonWithoutSessions(
       serialised,
+      // NOTE: At this point, we don't care about this attribute
+      {},
       AlwaysTrustingTrustManager(),
     );
 
@@ -95,51 +101,6 @@ void main() {
     final newDevice = await newSession.getDevice();
     expect(await oldDevice.equals(newDevice), true);
     expect(await oldSession.getDeviceMap(), await newSession.getDeviceMap());
-
-    expect(oldSession.getRatchetMap().length, newSession.getRatchetMap().length);
-    for (final session in oldSession.getRatchetMap().entries) {
-      expect(newSession.getRatchetMap().containsKey(session.key), true);
-
-      final oldRatchet = oldSession.getRatchetMap()[session.key]!;
-      final newRatchet = newSession.getRatchetMap()[session.key]!;
-      expect(await oldRatchet.equals(newRatchet), true);
-    }
-  });
-
-  test('Test serialising and deserialising the BlindTrustBeforeVerificationTrustManager', () async {
-    // Caroline's BTBV manager
-    final btbv = MemoryBTBVTrustManager();
-    // Example data
-    const aliceJid = 'alice@some.server';
-    const bobJid = 'bob@other.server';
-    
-    // Caroline starts a chat a device from Alice
-    await btbv.onNewSession(aliceJid, 1);
-    expect(await btbv.isTrusted(aliceJid, 1), true);
-    expect(await btbv.isEnabled(aliceJid, 1), true);
-
-    // Caroline meets with Alice and verifies her fingerprint
-    await btbv.setDeviceTrust(aliceJid, 1, BTBVTrustState.verified);
-    expect(await btbv.isTrusted(aliceJid, 1), true);
-
-    // Alice adds a new device
-    await btbv.onNewSession(aliceJid, 2);
-    expect(await btbv.isTrusted(aliceJid, 2), false);
-    expect(btbv.getDeviceTrust(aliceJid, 2), BTBVTrustState.notTrusted);
-    expect(await btbv.isEnabled(aliceJid, 2), false);
-
-    // Caronline starts a chat with Bob but since they live far apart, Caroline cannot
-    // verify his fingerprint.
-    await btbv.onNewSession(bobJid, 3);
-
-    // Bob adds a new device
-    await btbv.onNewSession(bobJid, 4);
-    expect(await btbv.isTrusted(bobJid, 3), true);
-    expect(await btbv.isTrusted(bobJid, 4), true);
-    expect(btbv.getDeviceTrust(bobJid, 3), BTBVTrustState.blindTrust);
-    expect(btbv.getDeviceTrust(bobJid, 4), BTBVTrustState.blindTrust);
-    expect(await btbv.isEnabled(bobJid, 3), true);
-    expect(await btbv.isEnabled(bobJid, 4), true);
   });
 
   test('Test serializing and deserializing RatchetMapKey', () {
@@ -167,21 +128,19 @@ void main() {
     await btbv.onNewSession(bobJid, 3);
     await btbv.onNewSession(bobJid, 4);
 
-    final managerJson = await btbv.toJson();
-    final managerString = jsonEncode(managerJson);
-    final managerPostJson = jsonDecode(managerString) as Map<String, dynamic>;
+    final serialized = jsonify(await btbv.toJson());
     final deviceList = BlindTrustBeforeVerificationTrustManager.deviceListFromJson(
-      managerPostJson,
+      serialized,
     );
     expect(btbv.devices, deviceList);
 
     final trustCache = BlindTrustBeforeVerificationTrustManager.trustCacheFromJson(
-      managerPostJson,
+      serialized,
     );
     expect(btbv.trustCache, trustCache);
 
     final enableCache = BlindTrustBeforeVerificationTrustManager.enableCacheFromJson(
-      managerPostJson,
+      serialized,
     );
     expect(btbv.enablementCache, enableCache);
   });