towards factoring out cyclic dependencies

1 files changed, 182 insertions, 0 deletions

diff --git a/packages/taler-wallet-core/src/common.ts b/packages/taler-wallet-core/src/common.ts
new file mode 100644
index 000000000..cbbbb1e32
--- /dev/null
+++ b/packages/taler-wallet-core/src/common.ts
@@ -0,0 +1,182 @@
+/*
+ This file is part of GNU Taler
+ (C) 2019 GNUnet e.V.
+
+ 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/>
+ */
+
+/**
+ * Imports.
+ */
+import {
+  WalletNotification,
+  BalancesResponse,
+  Logger,
+} from "@gnu-taler/taler-util";
+import { CryptoApi, CryptoWorkerFactory } from "./crypto/workers/cryptoApi.js";
+import { ExchangeDetailsRecord, ExchangeRecord, WalletStoresV1 } from "./db.js";
+import { PendingOperationsResponse } from "./pending-types.js";
+import { AsyncOpMemoMap, AsyncOpMemoSingle } from "./util/asyncMemo.js";
+import { HttpRequestLibrary } from "./util/http.js";
+import {
+  AsyncCondition,
+  OpenedPromise,
+  openPromise,
+} from "./util/promiseUtils.js";
+import { DbAccess, GetReadOnlyAccess } from "./util/query.js";
+import { TimerGroup } from "./util/timer.js";
+
+type NotificationListener = (n: WalletNotification) => void;
+
+const logger = new Logger("state.ts");
+
+export const EXCHANGE_COINS_LOCK = "exchange-coins-lock";
+export const EXCHANGE_RESERVES_LOCK = "exchange-reserves-lock";
+
+export interface TrustInfo {
+  isTrusted: boolean;
+  isAudited: boolean;
+}
+
+/**
+ * Interface for exchange-related operations.
+ */
+export interface ExchangeOperations {
+  // FIXME:  Should other operations maybe always use
+  // updateExchangeFromUrl?
+  getExchangeDetails(
+    tx: GetReadOnlyAccess<{
+      exchanges: typeof WalletStoresV1.exchanges;
+      exchangeDetails: typeof WalletStoresV1.exchangeDetails;
+    }>,
+    exchangeBaseUrl: string,
+  ): Promise<ExchangeDetailsRecord | undefined>;
+  getExchangeTrust(
+    ws: InternalWalletState,
+    exchangeInfo: ExchangeRecord,
+  ): Promise<TrustInfo>;
+  updateExchangeFromUrl(
+    ws: InternalWalletState,
+    baseUrl: string,
+    forceNow?: boolean,
+  ): Promise<{
+    exchange: ExchangeRecord;
+    exchangeDetails: ExchangeDetailsRecord;
+  }>;
+}
+
+/**
+ * Internal state of the wallet.
+ */
+export class InternalWalletState {
+  memoProcessReserve: AsyncOpMemoMap<void> = new AsyncOpMemoMap();
+  memoMakePlanchet: AsyncOpMemoMap<void> = new AsyncOpMemoMap();
+  memoGetPending: AsyncOpMemoSingle<PendingOperationsResponse> = new AsyncOpMemoSingle();
+  memoGetBalance: AsyncOpMemoSingle<BalancesResponse> = new AsyncOpMemoSingle();
+  memoProcessRefresh: AsyncOpMemoMap<void> = new AsyncOpMemoMap();
+  memoProcessRecoup: AsyncOpMemoMap<void> = new AsyncOpMemoMap();
+  memoProcessDeposit: AsyncOpMemoMap<void> = new AsyncOpMemoMap();
+  cryptoApi: CryptoApi;
+
+  timerGroup: TimerGroup = new TimerGroup();
+  latch = new AsyncCondition();
+  stopped = false;
+  memoRunRetryLoop = new AsyncOpMemoSingle<void>();
+
+  listeners: NotificationListener[] = [];
+
+  initCalled: boolean = false;
+
+  exchangeOps: ExchangeOperations;
+
+  /**
+   * Promises that are waiting for a particular resource.
+   */
+  private resourceWaiters: Record<string, OpenedPromise<void>[]> = {};
+
+  /**
+   * Resources that are currently locked.
+   */
+  private resourceLocks: Set<string> = new Set();
+
+  constructor(
+    // FIXME: Make this a getter and make
+    // the actual value nullable.
+    // Check if we are in a DB migration / garbage collection
+    // and throw an error in that case.
+    public db: DbAccess<typeof WalletStoresV1>,
+    public http: HttpRequestLibrary,
+    cryptoWorkerFactory: CryptoWorkerFactory,
+  ) {
+    this.cryptoApi = new CryptoApi(cryptoWorkerFactory);
+  }
+
+  notify(n: WalletNotification): void {
+    logger.trace("Notification", n);
+    for (const l of this.listeners) {
+      const nc = JSON.parse(JSON.stringify(n));
+      setTimeout(() => {
+        l(nc);
+      }, 0);
+    }
+  }
+
+  addNotificationListener(f: (n: WalletNotification) => void): void {
+    this.listeners.push(f);
+  }
+
+  /**
+   * Stop ongoing processing.
+   */
+  stop(): void {
+    this.stopped = true;
+    this.timerGroup.stopCurrentAndFutureTimers();
+    this.cryptoApi.stop();
+  }
+
+  /**
+   * Run an async function after acquiring a list of locks, identified
+   * by string tokens.
+   */
+  async runSequentialized<T>(tokens: string[], f: () => Promise<T>) {
+    // Make sure locks are always acquired in the same order
+    tokens = [...tokens].sort();
+
+    for (const token of tokens) {
+      if (this.resourceLocks.has(token)) {
+        const p = openPromise<void>();
+        let waitList = this.resourceWaiters[token];
+        if (!waitList) {
+          waitList = this.resourceWaiters[token] = [];
+        }
+        waitList.push(p);
+        await p.promise;
+      }
+      this.resourceLocks.add(token);
+    }
+
+    try {
+      logger.trace(`begin exclusive execution on ${JSON.stringify(tokens)}`);
+      const result = await f();
+      logger.trace(`end exclusive execution on ${JSON.stringify(tokens)}`);
+      return result;
+    } finally {
+      for (const token of tokens) {
+        this.resourceLocks.delete(token);
+        let waiter = (this.resourceWaiters[token] ?? []).shift();
+        if (waiter) {
+          waiter.resolve();
+        }
+      }
+    }
+  }
+}