uploadInboundGroupSessions method

Future<void> uploadInboundGroupSessions({ bool skipIfInProgress = false, })

This task should be performed after sync processing but should not block the sync. To make sure that it never gets executed multiple times, it is skipped when an upload task is already in progress. Set skipIfInProgress to false to await the pending upload task instead.

Implementation

Future<void> uploadInboundGroupSessions(
    {bool skipIfInProgress = false}) async {
  final database = client.database;
  final userID = client.userID;
  if (database == null || userID == null) {
    return;
  }

  // Make sure to not run in parallel
  if (_uploadingFuture != null) {
    if (skipIfInProgress) return;
    try {
      await _uploadingFuture;
    } finally {
      // shouldn't be necessary, since it will be unset already by the other process that started it, but just to be safe, also unset the future here
      _uploadingFuture = null;
    }
  }

  Future<void> uploadInternal() async {
    try {
      await client.userDeviceKeysLoading;

      if (!(await isCached())) {
        return; // we can't backup anyways
      }
      final dbSessions = await database.getInboundGroupSessionsToUpload();
      if (dbSessions.isEmpty) {
        return; // nothing to do
      }
      final privateKey =
          base64decodeUnpadded((await encryption.ssss.getCached(megolmKey))!);
      // decryption is needed to calculate the public key and thus see if the claimed information is in fact valid
      final decryption = olm.PkDecryption();
      final info = await getRoomKeysBackupInfo(false);
      String backupPubKey;
      try {
        backupPubKey = decryption.init_with_private_key(privateKey);

        if (info.algorithm !=
                BackupAlgorithm.mMegolmBackupV1Curve25519AesSha2 ||
            info.authData['public_key'] != backupPubKey) {
          decryption.free();
          return;
        }
        final args = GenerateUploadKeysArgs(
          pubkey: backupPubKey,
          dbSessions: <DbInboundGroupSessionBundle>[],
          userId: userID,
        );
        // we need to calculate verified beforehand, as else we pass a closure to an isolate
        // with 500 keys they do, however, noticably block the UI, which is why we give brief async suspentions in here
        // so that the event loop can progress
        var i = 0;
        for (final dbSession in dbSessions) {
          final device =
              client.getUserDeviceKeysByCurve25519Key(dbSession.senderKey);
          args.dbSessions.add(DbInboundGroupSessionBundle(
            dbSession: dbSession,
            verified: device?.verified ?? false,
          ));
          i++;
          if (i > 10) {
            await Future.delayed(Duration(milliseconds: 1));
            i = 0;
          }
        }
        final roomKeys =
            await client.nativeImplementations.generateUploadKeys(args);
        Logs().i('[Key Manager] Uploading ${dbSessions.length} room keys...');
        // upload the payload...
        await client.putRoomKeys(info.version, roomKeys);
        // and now finally mark all the keys as uploaded
        // no need to optimze this, as we only run it so seldomly and almost never with many keys at once
        for (final dbSession in dbSessions) {
          await database.markInboundGroupSessionAsUploaded(
              dbSession.roomId, dbSession.sessionId);
        }
      } finally {
        decryption.free();
      }
    } catch (e, s) {
      Logs().e('[Key Manager] Error uploading room keys', e, s);
    }
  }

  _uploadingFuture = uploadInternal();
  try {
    await _uploadingFuture;
  } finally {
    _uploadingFuture = null;
  }
}