ESM: Added BackgroundWorkerWaiter for running Magic on output in the background

src/web/BackgroundWorkerWaiter.mjs

@@ -0,0 +1,156 @@
+/**
+ * @author n1474335 [n1474335@gmail.com]
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+
+import ChefWorker from "worker-loader?inline&fallback=false!../core/ChefWorker";
+
+/**
+ * Waiter to handle conversations with a ChefWorker in the background.
+ */
+class BackgroundWorkerWaiter {
+
+    /**
+     * BackgroundWorkerWaiter constructor.
+     *
+     * @param {App} app - The main view object for CyberChef.
+     * @param {Manager} manager - The CyberChef event manager.
+     */
+    constructor(app, manager) {
+        this.app = app;
+        this.manager = manager;
+
+        this.callbacks = {};
+        this.callbackID = 0;
+        this.completedCallback = -1;
+        this.timeout = null;
+    }
+
+
+    /**
+     * Sets up the ChefWorker and associated listeners.
+     */
+    registerChefWorker() {
+        log.debug("Registering new background ChefWorker");
+        this.chefWorker = new ChefWorker();
+        this.chefWorker.addEventListener("message", this.handleChefMessage.bind(this));
+
+        let docURL = document.location.href.split(/[#?]/)[0];
+        const index = docURL.lastIndexOf("/");
+        if (index > 0) {
+            docURL = docURL.substring(0, index);
+        }
+        this.chefWorker.postMessage({"action": "docURL", "data": docURL});
+    }
+
+
+    /**
+     * Handler for messages sent back by the ChefWorker.
+     *
+     * @param {MessageEvent} e
+     */
+    handleChefMessage(e) {
+        const r = e.data;
+        log.debug("Receiving '" + r.action + "' from ChefWorker in the background");
+
+        switch (r.action) {
+            case "bakeComplete":
+            case "bakeError":
+                if (typeof r.data.id !== "undefined") {
+                    clearTimeout(this.timeout);
+                    this.callbacks[r.data.id].bind(this)(r.data);
+                    this.completedCallback = r.data.id;
+                }
+                break;
+            case "workerLoaded":
+                log.debug("Background ChefWorker loaded");
+                break;
+            case "optionUpdate":
+                // Ignore these messages
+                break;
+            default:
+                log.error("Unrecognised message from background ChefWorker", e);
+                break;
+        }
+    }
+
+
+    /**
+     * Cancels the current bake by terminating the ChefWorker and creating a new one.
+     */
+    cancelBake() {
+        if (this.chefWorker)
+            this.chefWorker.terminate();
+        this.registerChefWorker();
+    }
+
+
+    /**
+     * Asks the ChefWorker to bake the input using the specified recipe.
+     *
+     * @param {string} input
+     * @param {Object[]} recipeConfig
+     * @param {Object} options
+     * @param {number} progress
+     * @param {boolean} step
+     * @param {Function} callback
+     */
+    bake(input, recipeConfig, options, progress, step, callback) {
+        const id = this.callbackID++;
+        this.callbacks[id] = callback;
+
+        this.chefWorker.postMessage({
+            action: "bake",
+            data: {
+                input: input,
+                recipeConfig: recipeConfig,
+                options: options,
+                progress: progress,
+                step: step,
+                id: id
+            }
+        });
+    }
+
+
+    /**
+     * Asks the Magic operation what it can do with the input data.
+     *
+     * @param {string|ArrayBuffer} input
+     */
+    magic(input) {
+        // If we're still working on the previous bake, cancel it before stating a new one.
+        if (this.completedCallback + 1 < this.callbackID) {
+            clearTimeout(this.timeout);
+            this.cancelBake();
+        }
+
+        this.bake(input, [
+            {
+                "op": "Magic",
+                "args": [3, false, false]
+            }
+        ], {}, 0, false, this.magicComplete);
+
+        // Cancel this bake if it takes too long.
+        this.timeout = setTimeout(this.cancelBake.bind(this), 3000);
+    }
+
+
+    /**
+     * Handler for completed Magic bakes.
+     *
+     * @param {Object} response
+     */
+    magicComplete(response) {
+        log.debug("--- Background Magic Bake complete ---");
+        if (!response || response.error) return;
+
+        this.manager.output.backgroundMagicResult(response.dish.value);
+    }
+
+}
+
+
+export default BackgroundWorkerWaiter;