1 files changed, 101 insertions, 0 deletions
diff --git a/packages/taler-wallet-core/src/operations/backup/state.ts b/packages/taler-wallet-core/src/operations/backup/state.ts
new file mode 100644
index 000000000..29c9402c7
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+++ b/packages/taler-wallet-core/src/operations/backup/state.ts
@@ -0,0 +1,101 @@
+/*
+ This file is part of GNU Taler
+ (C) 2020 Taler Systems SA
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+import {
+  ConfigRecord,
+  encodeCrock,
+  getRandomBytes,
+  Stores,
+  Timestamp,
+  TransactionHandle,
+} from "../..";
+import { checkDbInvariant } from "../../util/invariants";
+import { InternalWalletState } from "../state";
+
+export interface WalletBackupConfState {
+  deviceId: string;
+  walletRootPub: string;
+  walletRootPriv: string;
+  clocks: { [device_id: string]: number };
+
+  /**
+   * Last hash of the canonicalized plain-text backup.
+   *
+   * Used to determine whether the wallet's content changed
+   * and we need to bump the clock.
+   */
+  lastBackupPlainHash?: string;
+
+  /**
+   * Timestamp stored in the last backup.
+   */
+  lastBackupTimestamp?: Timestamp;
+
+  /**
+   * Last time we tried to do a backup.
+   */
+  lastBackupCheckTimestamp?: Timestamp;
+  lastBackupNonce?: string;
+}
+
+export const WALLET_BACKUP_STATE_KEY = "walletBackupState";
+
+export async function provideBackupState(
+  ws: InternalWalletState,
+): Promise<WalletBackupConfState> {
+  const bs: ConfigRecord<WalletBackupConfState> | undefined = await ws.db.get(
+    Stores.config,
+    WALLET_BACKUP_STATE_KEY,
+  );
+  if (bs) {
+    return bs.value;
+  }
+  // We need to generate the key outside of the transaction
+  // due to how IndexedDB works.
+  const k = await ws.cryptoApi.createEddsaKeypair();
+  const d = getRandomBytes(5);
+  // FIXME: device ID should be configured when wallet is initialized
+  // and be based on hostname
+  const deviceId = `wallet-core-${encodeCrock(d)}`;
+  return await ws.db.runWithWriteTransaction([Stores.config], async (tx) => {
+    let backupStateEntry:
+      | ConfigRecord<WalletBackupConfState>
+      | undefined = await tx.get(Stores.config, WALLET_BACKUP_STATE_KEY);
+    if (!backupStateEntry) {
+      backupStateEntry = {
+        key: WALLET_BACKUP_STATE_KEY,
+        value: {
+          deviceId,
+          clocks: { [deviceId]: 1 },
+          walletRootPub: k.pub,
+          walletRootPriv: k.priv,
+          lastBackupPlainHash: undefined,
+        },
+      };
+      await tx.put(Stores.config, backupStateEntry);
+    }
+    return backupStateEntry.value;
+  });
+}
+
+export async function getWalletBackupState(
+  ws: InternalWalletState,
+  tx: TransactionHandle<typeof Stores.config>,
+): Promise<WalletBackupConfState> {
+  let bs = await tx.get(Stores.config, WALLET_BACKUP_STATE_KEY);
+  checkDbInvariant(!!bs, "wallet backup state should be in DB");
+  return bs.value;
+}