1 files changed, 162 insertions, 0 deletions
diff --git a/src/crypto/synchronousWorker.ts b/src/crypto/synchronousWorker.ts
new file mode 100644
index 000000000..d8a3d83cb
--- /dev/null
+++ b/src/crypto/synchronousWorker.ts
@@ -0,0 +1,162 @@
+/*
+ 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/>
+ */
+
+import { EmscEnvironment } from "./emscInterface";
+import { CryptoImplementation } from "./cryptoImplementation";
+
+/**
+ * Worker implementation that uses node subprocesses.
+ */
+export class SynchronousCryptoWorker {
+  private cachedEmscEnvironment: EmscEnvironment | undefined = undefined;
+  private cachedEmscEnvironmentPromise: Promise<EmscEnvironment> | undefined = undefined;
+
+  /**
+   * Function to be called when we receive a message from the worker thread.
+   */
+  onmessage: undefined | ((m: any) => void);
+
+  /**
+   * Function to be called when we receive an error from the worker thread.
+   */
+  onerror: undefined | ((m: any) => void);
+
+  constructor() {
+    this.onerror = undefined;
+    this.onmessage = undefined;
+  }
+
+  /**
+   * Add an event listener for either an "error" or "message" event.
+   */
+  addEventListener(event: "message" | "error", fn: (x: any) => void): void {
+    switch (event) {
+      case "message":
+        this.onmessage = fn;
+        break;
+      case "error":
+        this.onerror = fn;
+        break;
+    }
+  }
+
+  private getEmscriptenEnvironment(): Promise<EmscEnvironment> {
+    if (this.cachedEmscEnvironment) {
+      return Promise.resolve(this.cachedEmscEnvironment);
+    }
+
+    if (this.cachedEmscEnvironmentPromise) {
+      return this.cachedEmscEnvironmentPromise;
+    }
+
+    // Make sure that TypeScript doesn't try
+    // to check the taler-emscripten-lib.
+    const indirectRequire = require;
+
+    const g = global;
+
+    // unavoidable hack, so that emscripten detects
+    // the environment as node even though importScripts
+    // is present.
+
+    // @ts-ignore
+    const savedImportScripts = g.importScripts;
+    // @ts-ignore
+    delete g.importScripts;
+
+    // Assume that the code is run from the build/ directory.
+    const libFn = indirectRequire(
+      "../../../emscripten/taler-emscripten-lib.js",
+    );
+    const lib = libFn();
+    // @ts-ignore
+    g.importScripts = savedImportScripts;
+
+    if (!lib) {
+      throw Error("could not load taler-emscripten-lib.js");
+    }
+
+    if (!lib.ccall) {
+      throw Error(
+        "sanity check failed: taler-emscripten lib does not have 'ccall'",
+      );
+    }
+
+    this.cachedEmscEnvironmentPromise = new Promise((resolve, reject) => {
+      lib.onRuntimeInitialized = () => {
+        this.cachedEmscEnvironmentPromise = undefined;
+        this.cachedEmscEnvironment = new EmscEnvironment(lib);
+        resolve(this.cachedEmscEnvironment);
+      };
+    });
+    return this.cachedEmscEnvironmentPromise;
+  }
+
+  private dispatchMessage(msg: any) {
+    if (this.onmessage) {
+      this.onmessage({ data: msg });
+    }
+  }
+
+  private async handleRequest(operation: string, id: number, args: string[]) {
+    let emsc = await this.getEmscriptenEnvironment();
+
+    const impl = new CryptoImplementation(emsc);
+
+    if (!(operation in impl)) {
+      console.error(`crypto operation '${operation}' not found`);
+      return;
+    }
+
+    try {
+      const result = (impl as any)[operation](...args);
+      this.dispatchMessage({ result, id });
+    } catch (e) {
+      console.log("error during operation", e);
+      return;
+    }
+  }
+
+  /**
+   * Send a message to the worker thread.
+   */
+  postMessage(msg: any) {
+    const args = msg.args;
+    if (!Array.isArray(args)) {
+      console.error("args must be array");
+      return;
+    }
+    const id = msg.id;
+    if (typeof id !== "number") {
+      console.error("RPC id must be number");
+      return;
+    }
+    const operation = msg.operation;
+    if (typeof operation !== "string") {
+      console.error("RPC operation must be string");
+      return;
+    }
+
+    this.handleRequest(operation, id, args);
+  }
+
+  /**
+   * Forcibly terminate the worker thread.
+   */
+  terminate() {
+    console.log("terminating synchronous worker (no-op)");
+  }
+}