[api-minor] Re-factor how the useWorkerFetch option is used internally

With the recently added OpenJPEG no-wasm fallback we need to send the `wasmUrl` option to the worker-thread *regardless* of the value of the `useWorkerFetch` option, since the fallback won't work if we don't have a URL to `import` it from.
For consistency the code is re-factored to always send the factory-urls to the worker-thread, and simply check the `useWorkerFetch` option there instead.

Also, as a follow-up to PR 19525, introduce a new `useWasm` option that can be used in e.g. browser-tests to forcibly disable WebAssembly usage.

src/core/evaluator.js

@@ -90,6 +90,8 @@ const DefaultPartialEvaluatorOptions = Object.freeze({
   canvasMaxAreaInBytes: -1,
   fontExtraProperties: false,
   useSystemFonts: true,
+  useWasm: true,
+  useWorkerFetch: true,
   cMapUrl: null,
   standardFontDataUrl: null,
   wasmUrl: null,
@@ -384,7 +386,7 @@ class PartialEvaluator {
     }
     let data;
 
-    if (this.options.cMapUrl !== null) {
+    if (this.options.useWorkerFetch) {
       // Only compressed CMaps are (currently) supported here.
       data = {
         cMapData: await fetchBinaryData(`${this.options.cMapUrl}${name}.bcmap`),
@@ -424,7 +426,7 @@ class PartialEvaluator {
     let data;
 
     try {
-      if (this.options.standardFontDataUrl !== null) {
+      if (this.options.useWorkerFetch) {
         data = await fetchBinaryData(
           `${this.options.standardFontDataUrl}${filename}`
         );

src/core/jpx.js

@@ -31,24 +31,26 @@ class JpxImage {
 
   static #modulePromise = null;
 
-  static #hasJSFallback = false;
+  static #useWasm = true;
+
+  static #useWorkerFetch = true;
 
   static #wasmUrl = null;
 
-  static setOptions({ handler, wasmUrl }) {
+  static setOptions({ handler, useWasm, useWorkerFetch, wasmUrl }) {
-    if (this.#buffer || this.#hasJSFallback || this.#modulePromise) {
+    if (this.#buffer || this.#modulePromise) {
       return;
     }
-    this.#wasmUrl = wasmUrl || null;
+    this.#useWasm = useWasm;
-    if (wasmUrl === null) {
+    this.#useWorkerFetch = useWorkerFetch;
+    this.#wasmUrl = wasmUrl;
+
+    if (!useWorkerFetch) {
       this.#handler = handler;
     }
   }
 
   static async #getJsModule(fallbackCallback) {
-    if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("TESTING")) {
-      this.#wasmUrl ??= "/build/generic/web/wasm/";
-    }
     const path =
       typeof PDFJSDev === "undefined"
         ? `../${this.#wasmUrl}openjpeg_nowasm_fallback.js`
@@ -63,8 +65,6 @@ class JpxImage {
     } catch (e) {
       warn(`JpxImage#getJsModule: ${e}`);
     }
-
-    this.#hasJSFallback = true;
     fallbackCallback(instance);
   }
 
@@ -72,7 +72,7 @@ class JpxImage {
     const filename = "openjpeg.wasm";
     try {
       if (!this.#buffer) {
-        if (this.#wasmUrl !== null) {
+        if (this.#useWorkerFetch) {
           this.#buffer = await fetchBinaryData(`${this.#wasmUrl}${filename}`);
         } else {
           this.#buffer = await this.#handler.sendWithPromise(
@@ -100,7 +100,7 @@ class JpxImage {
     if (!this.#modulePromise) {
       const { promise, resolve } = Promise.withResolvers();
       const promises = [promise];
-      if (this.#hasJSFallback) {
+      if (!this.#useWasm) {
         this.#getJsModule(resolve);
       } else {
         promises.push(

src/display/api.js

@@ -144,6 +144,9 @@ const RENDERING_CANCELLED_TIMEOUT = 100; // ms
  *   the `CMapReaderFactory`, `StandardFontDataFactory`, and `WasmFactory`
  *   options are ignored.
  *   The default value is `true` in web environments and `false` in Node.js.
+ * @property {boolean} [useWasm] - Attempt to use WebAssembly in order to
+ *    improve e.g. image decoding performance.
+ *    The default value is `true`.
  * @property {boolean} [stopAtErrors] - Reject certain promises, e.g.
  *   `getOperatorList`, `getTextContent`, and `RenderTask`, when the associated
  *   PDF data cannot be successfully parsed, instead of attempting to recover
@@ -320,6 +323,7 @@ function getDocument(src = {}) {
       ? NodeFilterFactory
       : DOMFilterFactory);
   const enableHWA = src.enableHWA === true;
+  const useWasm = src.useWasm !== false;
 
   // Parameters whose default values depend on other parameters.
   const length = rangeTransport ? rangeTransport.length : (src.length ?? NaN);
@@ -410,9 +414,11 @@ function getDocument(src = {}) {
       canvasMaxAreaInBytes,
       fontExtraProperties,
       useSystemFonts,
-      cMapUrl: useWorkerFetch ? cMapUrl : null,
+      useWasm,
-      standardFontDataUrl: useWorkerFetch ? standardFontDataUrl : null,
+      useWorkerFetch,
-      wasmUrl: useWorkerFetch ? wasmUrl : null,
+      cMapUrl,
+      standardFontDataUrl,
+      wasmUrl,
     },
   };
   const transportParams = {

test/driver.js

@@ -638,10 +638,11 @@ class Driver {
           password: task.password,
           cMapUrl: CMAP_URL,
           standardFontDataUrl: STANDARD_FONT_DATA_URL,
-          wasmUrl: task.noWasm ? null : WASM_URL,
+          wasmUrl: WASM_URL,
           disableAutoFetch: !task.enableAutoFetch,
           pdfBug: true,
           useSystemFonts: task.useSystemFonts,
+          useWasm: task.useWasm,
           useWorkerFetch: task.useWorkerFetch,
           enableXfa: task.enableXfa,
           isOffscreenCanvasSupported,

test/test_manifest.json

@@ -6422,9 +6422,9 @@
     "id": "issue19326_nowasm",
     "file": "pdfs/issue19326.pdf",
     "md5": "b4d937017daf439a6318501428e0c6ba",
-    "noWasm": true,
     "rounds": 1,
-    "type": "eq"
+    "type": "eq",
+    "useWasm": false
   },
   {
     "id": "issue19326_main_thread_fetch",