1 files changed, 91 insertions, 0 deletions
diff --git a/toolkit/components/ml/content/MLEngine.worker.mjs b/toolkit/components/ml/content/MLEngine.worker.mjs
new file mode 100644
index 0000000000..1013977e07
--- /dev/null
+++ b/toolkit/components/ml/content/MLEngine.worker.mjs
@@ -0,0 +1,91 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import { PromiseWorker } from "resource://gre/modules/workers/PromiseWorker.mjs";
+
+// Respect the preference "browser.ml.logLevel".
+let _loggingLevel = "Error";
+function log(...args) {
+  if (_loggingLevel !== "Error" && _loggingLevel !== "Warn") {
+    console.log("ML:", ...args);
+  }
+}
+function trace(...args) {
+  if (_loggingLevel === "Trace" || _loggingLevel === "All") {
+    console.log("ML:", ...args);
+  }
+}
+
+/**
+ * The actual MLEngine lives here in a worker.
+ */
+class MLEngineWorker {
+  /** @type {ArrayBuffer} */
+  #wasm;
+  /** @type {ArrayBuffer} */
+  #model;
+
+  constructor() {
+    // Connect the provider to the worker.
+    this.#connectToPromiseWorker();
+  }
+
+  /**
+   * @param {ArrayBuffer} wasm
+   * @param {ArrayBuffer} model
+   * @param {string} loggingLevel
+   */
+  initializeEngine(wasm, model, loggingLevel) {
+    this.#wasm = wasm;
+    this.#model = model;
+    _loggingLevel = loggingLevel;
+    // TODO - Initialize the engine for real here.
+    log("MLEngineWorker is initalized");
+  }
+
+  /**
+   * Run the worker.
+   *
+   * @param {string} request
+   */
+  run(request) {
+    if (!this.#wasm) {
+      throw new Error("Expected the wasm to exist.");
+    }
+    if (!this.#model) {
+      throw new Error("Expected the model to exist");
+    }
+    if (request === "throw") {
+      throw new Error(
+        'Received the message "throw", so intentionally throwing an error.'
+      );
+    }
+    trace("inference run requested with:", request);
+    return request.slice(0, Math.floor(request.length / 2));
+  }
+
+  /**
+   * Glue code to connect the `MLEngineWorker` to the PromiseWorker interface.
+   */
+  #connectToPromiseWorker() {
+    const worker = new PromiseWorker.AbstractWorker();
+    worker.dispatch = (method, args = []) => {
+      if (!this[method]) {
+        throw new Error("Method does not exist: " + method);
+      }
+      return this[method](...args);
+    };
+    worker.close = () => self.close();
+    worker.postMessage = (message, ...transfers) => {
+      self.postMessage(message, ...transfers);
+    };
+
+    self.addEventListener("message", msg => worker.handleMessage(msg));
+    self.addEventListener("unhandledrejection", function (error) {
+      throw error.reason;
+    });
+  }
+}
+
+new MLEngineWorker();