Utilize private fields and methods more in the PDFWorker class

This replaces, wherever possible, the old semi-private fields and methods with actually private ones.

src/display/api.js

@@ -2091,6 +2091,14 @@ class LoopbackPort {
  * @param {PDFWorkerParameters} params - The worker initialization parameters.
  */
 class PDFWorker {
+  #capability = Promise.withResolvers();
+
+  #messageHandler = null;
+
+  #port = null;
+
+  #webWorker = null;
+
   static #fakeWorkerId = 0;
 
   static #isWorkerDisabled = false;
@@ -2158,20 +2166,24 @@ class PDFWorker {
     this.destroyed = false;
     this.verbosity = verbosity;
 
-    this._readyCapability = Promise.withResolvers();
-    this._port = null;
-    this._webWorker = null;
-    this._messageHandler = null;
-
     if (port) {
       if (PDFWorker.#workerPorts.has(port)) {
         throw new Error("Cannot use more than one PDFWorker per port.");
       }
       PDFWorker.#workerPorts.set(port, this);
-      this._initializeFromPort(port);
-      return;
+      this.#initializeFromPort(port);
+    } else {
+      this.#initialize();
+    }
+
+    if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
+      // For testing purposes.
+      Object.defineProperty(this, "_webWorker", {
+        get() {
+          return this.#webWorker;
+        },
+      });
     }
-    this._initialize();
   }
 
   /**
@@ -2179,13 +2191,13 @@ class PDFWorker {
    * @type {Promise<void>}
    */
   get promise() {
-    return this._readyCapability.promise;
+    return this.#capability.promise;
   }
 
   #resolve() {
-    this._readyCapability.resolve();
+    this.#capability.resolve();
     // Send global setting, e.g. verbosity level.
-    this._messageHandler.send("configure", {
+    this.#messageHandler.send("configure", {
       verbosity: this.verbosity,
     });
   }
@@ -2195,7 +2207,7 @@ class PDFWorker {
    * @type {Worker}
    */
   get port() {
-    return this._port;
+    return this.#port;
   }
 
   /**
@@ -2203,20 +2215,20 @@ class PDFWorker {
    * @type {MessageHandler}
    */
   get messageHandler() {
-    return this._messageHandler;
+    return this.#messageHandler;
   }
 
-  _initializeFromPort(port) {
-    this._port = port;
-    this._messageHandler = new MessageHandler("main", "worker", port);
-    this._messageHandler.on("ready", function () {
+  #initializeFromPort(port) {
+    this.#port = port;
+    this.#messageHandler = new MessageHandler("main", "worker", port);
+    this.#messageHandler.on("ready", () => {
       // Ignoring "ready" event -- MessageHandler should already be initialized
       // and ready to accept messages.
     });
     this.#resolve();
   }
 
-  _initialize() {
+  #initialize() {
     // If worker support isn't disabled explicit and the browser has worker
     // support, create a new web worker and test if it/the browser fulfills
     // all requirements to run parts of pdf.js in a web worker.
@@ -2226,7 +2238,7 @@ class PDFWorker {
       PDFWorker.#isWorkerDisabled ||
       PDFWorker.#mainThreadWorkerMessageHandler
     ) {
-      this._setupFakeWorker();
+      this.#setupFakeWorker();
       return;
     }
     let { workerSrc } = PDFWorker;
@@ -2251,11 +2263,11 @@ class PDFWorker {
         messageHandler.destroy();
         worker.terminate();
         if (this.destroyed) {
-          this._readyCapability.reject(new Error("Worker was destroyed"));
+          this.#capability.reject(new Error("Worker was destroyed"));
         } else {
           // Fall back to fake worker if the termination is caused by an
           // error (e.g. NetworkError / SecurityError).
-          this._setupFakeWorker();
+          this.#setupFakeWorker();
         }
       };
 
@@ -2263,7 +2275,7 @@ class PDFWorker {
       worker.addEventListener(
         "error",
         () => {
-          if (!this._webWorker) {
+          if (!this.#webWorker) {
             // Worker failed to initialize due to an error. Clean up and fall
             // back to the fake worker.
             terminateEarly();
@@ -2278,9 +2290,9 @@ class PDFWorker {
           terminateEarly();
           return;
         }
-        this._messageHandler = messageHandler;
-        this._port = worker;
-        this._webWorker = worker;
+        this.#messageHandler = messageHandler;
+        this.#port = worker;
+        this.#webWorker = worker;
 
         this.#resolve();
       });
@@ -2295,7 +2307,7 @@ class PDFWorker {
           sendTest();
         } catch {
           // We need fallback to a faked worker.
-          this._setupFakeWorker();
+          this.#setupFakeWorker();
         }
       });
 
@@ -2315,10 +2327,10 @@ class PDFWorker {
     }
     // Either workers are not supported or have thrown an exception.
     // Thus, we fallback to a faked worker.
-    this._setupFakeWorker();
+    this.#setupFakeWorker();
   }
 
-  _setupFakeWorker() {
+  #setupFakeWorker() {
     if (!PDFWorker.#isWorkerDisabled) {
       warn("Setting up fake worker.");
       PDFWorker.#isWorkerDisabled = true;
@@ -2327,11 +2339,11 @@ class PDFWorker {
     PDFWorker._setupFakeWorkerGlobal
       .then(WorkerMessageHandler => {
         if (this.destroyed) {
-          this._readyCapability.reject(new Error("Worker was destroyed"));
+          this.#capability.reject(new Error("Worker was destroyed"));
           return;
         }
         const port = new LoopbackPort();
-        this._port = port;
+        this.#port = port;
 
         // All fake workers use the same port, making id unique.
         const id = `fake${PDFWorker.#fakeWorkerId++}`;
@@ -2341,11 +2353,11 @@ class PDFWorker {
         const workerHandler = new MessageHandler(id + "_worker", id, port);
         WorkerMessageHandler.setup(workerHandler, port);
 
-        this._messageHandler = new MessageHandler(id, id + "_worker", port);
+        this.#messageHandler = new MessageHandler(id, id + "_worker", port);
         this.#resolve();
       })
       .catch(reason => {
-        this._readyCapability.reject(
+        this.#capability.reject(
           new Error(`Setting up fake worker failed: "${reason.message}".`)
         );
       });
@@ -2358,14 +2370,14 @@ class PDFWorker {
     this.destroyed = true;
 
     // We need to terminate only web worker created resource.
-    this._webWorker?.terminate();
-    this._webWorker = null;
+    this.#webWorker?.terminate();
+    this.#webWorker = null;
 
-    PDFWorker.#workerPorts.delete(this._port);
-    this._port = null;
+    PDFWorker.#workerPorts.delete(this.#port);
+    this.#port = null;
 
-    this._messageHandler?.destroy();
-    this._messageHandler = null;
+    this.#messageHandler?.destroy();
+    this.#messageHandler = null;
   }
 
   /**