Merge pull request #13882 from Snuffleupagus/PDFWorker-rm-closure

[api-minor] Remove the closure from the `PDFWorker` class, in the `src/display/api.js` file

src/display/api.js

@@ -1938,129 +1938,59 @@ class LoopbackPort {
  *   the constants from {@link VerbosityLevel} should be used.
  */
 
-/** @type {any} */
+const PDFWorkerUtil = {
-const PDFWorker = (function PDFWorkerClosure() {
+  isWorkerDisabled: false,
-  const pdfWorkerPorts = new WeakMap();
+  fallbackWorkerSrc: null,
-  let isWorkerDisabled = false;
+  fakeWorkerId: 0,
-  let fallbackWorkerSrc;
+};
-  let nextFakeWorkerId = 0;
+if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("GENERIC")) {
-  let fakeWorkerCapability;
-
-  if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("GENERIC")) {
   // eslint-disable-next-line no-undef
   if (isNodeJS && typeof __non_webpack_require__ === "function") {
     // Workers aren't supported in Node.js, force-disabling them there.
-      isWorkerDisabled = true;
+    PDFWorkerUtil.isWorkerDisabled = true;
 
-      fallbackWorkerSrc = PDFJSDev.test("LIB")
+    PDFWorkerUtil.fallbackWorkerSrc = PDFJSDev.test("LIB")
       ? "../pdf.worker.js"
       : "./pdf.worker.js";
   } else if (typeof document === "object") {
     const pdfjsFilePath = document?.currentScript?.src;
     if (pdfjsFilePath) {
-        fallbackWorkerSrc = pdfjsFilePath.replace(
+      PDFWorkerUtil.fallbackWorkerSrc = pdfjsFilePath.replace(
         /(\.(?:min\.)?js)(\?.*)?$/i,
         ".worker$1$2"
       );
     }
   }
-  }
 
-  function getWorkerSrc() {
+  PDFWorkerUtil.createCDNWrapper = function (url) {
-    if (GlobalWorkerOptions.workerSrc) {
-      return GlobalWorkerOptions.workerSrc;
-    }
-    if (typeof fallbackWorkerSrc !== "undefined") {
-      if (!isNodeJS) {
-        deprecated('No "GlobalWorkerOptions.workerSrc" specified.');
-      }
-      return fallbackWorkerSrc;
-    }
-    throw new Error('No "GlobalWorkerOptions.workerSrc" specified.');
-  }
-
-  function getMainThreadWorkerMessageHandler() {
-    try {
-      return globalThis.pdfjsWorker?.WorkerMessageHandler || null;
-    } catch (ex) {
-      return null;
-    }
-  }
-
-  // Loads worker code into main-thread.
-  function setupFakeWorkerGlobal() {
-    if (fakeWorkerCapability) {
-      return fakeWorkerCapability.promise;
-    }
-    fakeWorkerCapability = createPromiseCapability();
-
-    const loader = async function () {
-      const mainWorkerMessageHandler = getMainThreadWorkerMessageHandler();
-
-      if (mainWorkerMessageHandler) {
-        // The worker was already loaded using e.g. a `<script>` tag.
-        return mainWorkerMessageHandler;
-      }
-      if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("PRODUCTION")) {
-        const worker = await import("pdfjs/core/worker.js");
-        return worker.WorkerMessageHandler;
-      }
-      if (
-        PDFJSDev.test("GENERIC") &&
-        isNodeJS &&
-        // eslint-disable-next-line no-undef
-        typeof __non_webpack_require__ === "function"
-      ) {
-        // Since bundlers, such as Webpack, cannot be told to leave `require`
-        // statements alone we are thus forced to jump through hoops in order
-        // to prevent `Critical dependency: ...` warnings in third-party
-        // deployments of the built `pdf.js`/`pdf.worker.js` files; see
-        // https://github.com/webpack/webpack/issues/8826
-        //
-        // The following hack is based on the assumption that code running in
-        // Node.js won't ever be affected by e.g. Content Security Policies that
-        // prevent the use of `eval`. If that ever occurs, we should revert this
-        // to a normal `__non_webpack_require__` statement and simply document
-        // the Webpack warnings instead (telling users to ignore them).
-        //
-        // eslint-disable-next-line no-eval
-        const worker = eval("require")(getWorkerSrc());
-        return worker.WorkerMessageHandler;
-      }
-      await loadScript(getWorkerSrc());
-      return window.pdfjsWorker.WorkerMessageHandler;
-    };
-    loader().then(fakeWorkerCapability.resolve, fakeWorkerCapability.reject);
-
-    return fakeWorkerCapability.promise;
-  }
-
-  function createCDNWrapper(url) {
     // We will rely on blob URL's property to specify origin.
     // We want this function to fail in case if createObjectURL or Blob do not
     // exist or fail for some reason -- our Worker creation will fail anyway.
-    const wrapper = "importScripts('" + url + "');";
+    const wrapper = `importScripts("${url}");`;
     return URL.createObjectURL(new Blob([wrapper]));
-  }
+  };
+}
 
-  /**
+/**
  * PDF.js web worker abstraction that controls the instantiation of PDF
  * documents. Message handlers are used to pass information from the main
  * thread to the worker thread and vice versa. If the creation of a web
  * worker is not possible, a "fake" worker will be used instead.
+ *
+ * @param {PDFWorkerParameters} params - The worker initialization parameters.
  */
-  // eslint-disable-next-line no-shadow
+class PDFWorker {
-  class PDFWorker {
+  static get _workerPorts() {
-    /**
+    return shadow(this, "_workerPorts", new WeakMap());
-     * @param {PDFWorkerParameters} params - Worker initialization parameters.
+  }
-     */
+
   constructor({
     name = null,
     port = null,
     verbosity = getVerbosityLevel(),
   } = {}) {
-      if (port && pdfWorkerPorts.has(port)) {
+    if (port && PDFWorker._workerPorts.has(port)) {
-        throw new Error("Cannot use more than one PDFWorker per port");
+      throw new Error("Cannot use more than one PDFWorker per port.");
     }
 
     this.name = name;
@@ -2074,21 +2004,33 @@ const PDFWorker = (function PDFWorkerClosure() {
     this._messageHandler = null;
 
     if (port) {
-        pdfWorkerPorts.set(port, this);
+      PDFWorker._workerPorts.set(port, this);
       this._initializeFromPort(port);
       return;
     }
     this._initialize();
   }
 
+  /**
+   * Promise for worker initialization completion.
+   * @type {Promise<void>}
+   */
   get promise() {
     return this._readyCapability.promise;
   }
 
+  /**
+   * The current `workerPort`, when it exists.
+   * @type {Worker}
+   */
   get port() {
     return this._port;
   }
 
+  /**
+   * The current MessageHandler-instance.
+   * @type {MessageHandler}
+   */
   get messageHandler() {
     return this._messageHandler;
   }
@@ -2097,8 +2039,8 @@ const PDFWorker = (function PDFWorkerClosure() {
     this._port = port;
     this._messageHandler = new MessageHandler("main", "worker", port);
     this._messageHandler.on("ready", function () {
-        // Ignoring 'ready' event -- MessageHandler shall be already initialized
+      // Ignoring "ready" event -- MessageHandler should already be initialized
-        // and ready to accept the messages.
+      // and ready to accept messages.
     });
     this._readyCapability.resolve();
   }
@@ -2111,10 +2053,10 @@ const PDFWorker = (function PDFWorkerClosure() {
     // Uint8Array as it arrives on the worker. (Chrome added this with v.15.)
     if (
       typeof Worker !== "undefined" &&
-        !isWorkerDisabled &&
+      !PDFWorkerUtil.isWorkerDisabled &&
-        !getMainThreadWorkerMessageHandler()
+      !PDFWorker._mainThreadWorkerMessageHandler
     ) {
-        let workerSrc = getWorkerSrc();
+      let workerSrc = PDFWorker.workerSrc;
 
       try {
         // Wraps workerSrc path into blob URL, if the former does not belong
@@ -2124,7 +2066,7 @@ const PDFWorker = (function PDFWorkerClosure() {
           PDFJSDev.test("GENERIC") &&
           !isSameOrigin(window.location.href, workerSrc)
         ) {
-            workerSrc = createCDNWrapper(
+          workerSrc = PDFWorkerUtil.createCDNWrapper(
             new URL(workerSrc, window.location).href
           );
         }
@@ -2196,9 +2138,7 @@ const PDFWorker = (function PDFWorkerClosure() {
         });
 
         const sendTest = () => {
-            const testObj = new Uint8Array([
+          const testObj = new Uint8Array([this.postMessageTransfers ? 255 : 0]);
-              this.postMessageTransfers ? 255 : 0,
-            ]);
           // Some versions of Opera throw a DATA_CLONE_ERR on serializing the
           // typed array. Also, checking if we can use transfers.
           try {
@@ -2210,10 +2150,9 @@ const PDFWorker = (function PDFWorkerClosure() {
           }
         };
 
-          // It might take time for worker to initialize (especially when AMD
+        // It might take time for the worker to initialize. We will try to send
-          // loader is used). We will try to send test immediately, and then
+        // the "test" message immediately, and once the "ready" message arrives.
-          // when 'ready' message will arrive. The worker shall process only
+        // The worker shall process only the first received "test" message.
-          // first received 'test'.
         sendTest();
         return;
       } catch (e) {
@@ -2226,12 +2165,12 @@ const PDFWorker = (function PDFWorkerClosure() {
   }
 
   _setupFakeWorker() {
-      if (!isWorkerDisabled) {
+    if (!PDFWorkerUtil.isWorkerDisabled) {
       warn("Setting up fake worker.");
-        isWorkerDisabled = true;
+      PDFWorkerUtil.isWorkerDisabled = true;
     }
 
-      setupFakeWorkerGlobal()
+    PDFWorker._setupFakeWorkerGlobal
       .then(WorkerMessageHandler => {
         if (this.destroyed) {
           this._readyCapability.reject(new Error("Worker was destroyed"));
@@ -2241,7 +2180,7 @@ const PDFWorker = (function PDFWorkerClosure() {
         this._port = port;
 
         // All fake workers use the same port, making id unique.
-          const id = "fake" + nextFakeWorkerId++;
+        const id = `fake${PDFWorkerUtil.fakeWorkerId++}`;
 
         // If the main thread is our worker, setup the handling for the
         // messages -- the main thread sends to it self.
@@ -2273,7 +2212,7 @@ const PDFWorker = (function PDFWorkerClosure() {
       this._webWorker.terminate();
       this._webWorker = null;
     }
-      pdfWorkerPorts.delete(this._port);
+    PDFWorker._workerPorts.delete(this._port);
     this._port = null;
     if (this._messageHandler) {
       this._messageHandler.destroy();
@@ -2282,25 +2221,93 @@ const PDFWorker = (function PDFWorkerClosure() {
   }
 
   /**
-     * @param {PDFWorkerParameters} params - The worker initialization
+   * @param {PDFWorkerParameters} params - The worker initialization parameters.
-     *   parameters.
    */
   static fromPort(params) {
-      if (!params || !params.port) {
+    if (!params?.port) {
       throw new Error("PDFWorker.fromPort - invalid method signature.");
     }
-      if (pdfWorkerPorts.has(params.port)) {
+    if (this._workerPorts.has(params.port)) {
-        return pdfWorkerPorts.get(params.port);
+      return this._workerPorts.get(params.port);
     }
     return new PDFWorker(params);
   }
 
-    static getWorkerSrc() {
+  /**
-      return getWorkerSrc();
+   * The current `workerSrc`, when it exists.
+   * @type {string}
+   */
+  static get workerSrc() {
+    if (GlobalWorkerOptions.workerSrc) {
+      return GlobalWorkerOptions.workerSrc;
+    }
+    if (PDFWorkerUtil.fallbackWorkerSrc !== null) {
+      if (!isNodeJS) {
+        deprecated('No "GlobalWorkerOptions.workerSrc" specified.');
+      }
+      return PDFWorkerUtil.fallbackWorkerSrc;
+    }
+    throw new Error('No "GlobalWorkerOptions.workerSrc" specified.');
+  }
+
+  static get _mainThreadWorkerMessageHandler() {
+    try {
+      return globalThis.pdfjsWorker?.WorkerMessageHandler || null;
+    } catch (ex) {
+      return null;
     }
   }
-  return PDFWorker;
+
-})();
+  // Loads worker code into the main-thread.
+  static get _setupFakeWorkerGlobal() {
+    const loader = async () => {
+      const mainWorkerMessageHandler = this._mainThreadWorkerMessageHandler;
+
+      if (mainWorkerMessageHandler) {
+        // The worker was already loaded using e.g. a `<script>` tag.
+        return mainWorkerMessageHandler;
+      }
+      if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("PRODUCTION")) {
+        const worker = await import("pdfjs/core/worker.js");
+        return worker.WorkerMessageHandler;
+      }
+      if (
+        PDFJSDev.test("GENERIC") &&
+        isNodeJS &&
+        // eslint-disable-next-line no-undef
+        typeof __non_webpack_require__ === "function"
+      ) {
+        // Since bundlers, such as Webpack, cannot be told to leave `require`
+        // statements alone we are thus forced to jump through hoops in order
+        // to prevent `Critical dependency: ...` warnings in third-party
+        // deployments of the built `pdf.js`/`pdf.worker.js` files; see
+        // https://github.com/webpack/webpack/issues/8826
+        //
+        // The following hack is based on the assumption that code running in
+        // Node.js won't ever be affected by e.g. Content Security Policies that
+        // prevent the use of `eval`. If that ever occurs, we should revert this
+        // to a normal `__non_webpack_require__` statement and simply document
+        // the Webpack warnings instead (telling users to ignore them).
+        //
+        // eslint-disable-next-line no-eval
+        const worker = eval("require")(this.workerSrc);
+        return worker.WorkerMessageHandler;
+      }
+      await loadScript(this.workerSrc);
+      return window.pdfjsWorker.WorkerMessageHandler;
+    };
+
+    return shadow(this, "_setupFakeWorkerGlobal", loader());
+  }
+}
+if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("GENERIC")) {
+  PDFWorker.getWorkerSrc = function () {
+    deprecated(
+      "`PDFWorker.getWorkerSrc()`, please use `PDFWorker.workerSrc` instead."
+    );
+    return this.workerSrc;
+  };
+}
 
 /**
  * For internal use only.

test/unit/api_spec.js

@@ -501,7 +501,7 @@ describe("api", function () {
         pending("Worker is not supported in Node.js.");
       }
 
-      const workerSrc = PDFWorker.getWorkerSrc();
+      const workerSrc = PDFWorker.workerSrc;
       expect(typeof workerSrc).toEqual("string");
       expect(workerSrc).toEqual(GlobalWorkerOptions.workerSrc);
     });

web/app.js

@@ -2139,7 +2139,7 @@ async function loadFakeWorker() {
     window.pdfjsWorker = await import("pdfjs/core/worker.js");
     return undefined;
   }
-  return loadScript(PDFWorker.getWorkerSrc());
+  return loadScript(PDFWorker.workerSrc);
 }
 
 function loadAndEnablePDFBug(enabledTabs) {