[api-minor] Replace the CMapReaderFactory, StandardFontDataFactory, and WasmFactory API options with a single factory/option

Currently we have no less than three different, but very similar, factories for reading built-in CMap files, standard font files, and wasm files on the main-thread.[1]
These factories were added at different points in time, since I cannot imagine that we'd add essentially three copies of the same code otherwise.

Nowadays these factories are often not even used[2], since worker-thread fetching is used whenever possible to improve performance. In particular, they will *only* be used when either:
 - The PDF.js library runs in Node.js environments.
 - The user manually sets `useWorkerFetch = false` when calling `getDocument`.
 - The user provides custom `CMapReaderFactory`, `StandardFontDataFactory`, and/or `WasmFactory` instances when calling `getDocument`.

By replacing these factories with *a single* new `BinaryDataFactory` factory/option the number of `getDocument` options are thus reduced, which cannot hurt.
This also reduces the total bundle-size of the Firefox PDF Viewer a little bit, and it slightly reduces the number of import maps that need to be maintained.

*Please note:* For users that provide custom `CMapReaderFactory`, `StandardFontDataFactory`, and `WasmFactory` instances when calling `getDocument` this will be a breaking change, however it's unlikely that (many) such users exist.
(The *internal* format data-format of `CMapReaderFactory` was changed in PR 18951, and there hasn't been a single question/complaint about it in well over a year.)

---

[1] Any new functionality could easily lead to more such factories being added in the future, which wouldn't be great.

[2] Note that the Firefox PDF Viewer no longer use these factories, since it "forcibly" sets `useWorkerFetch = true` during building.

Author: Snuffleupagus

gulpfile.mjs

@@ -195,9 +195,7 @@ function createWebpackAlias(defines) {
     "fluent-dom": "node_modules/@fluent/dom/esm/index.js",
   };
   const libraryAlias = {
-    "display-cmap_reader_factory": "src/display/stubs.js",
-    "display-standard_fontdata_factory": "src/display/stubs.js",
-    "display-wasm_factory": "src/display/stubs.js",
+    "display-binary_data_factory": "src/display/stubs.js",
     "display-fetch_stream": "src/display/stubs.js",
     "display-network": "src/display/stubs.js",
     "display-node_stream": "src/display/stubs.js",
@@ -227,11 +225,8 @@ function createWebpackAlias(defines) {
   };
 
   if (defines.CHROME) {
-    libraryAlias["display-cmap_reader_factory"] =
-      "src/display/cmap_reader_factory.js";
-    libraryAlias["display-standard_fontdata_factory"] =
-      "src/display/standard_fontdata_factory.js";
-    libraryAlias["display-wasm_factory"] = "src/display/wasm_factory.js";
+    libraryAlias["display-binary_data_factory"] =
+      "src/display/binary_data_factory.js";
     libraryAlias["display-fetch_stream"] = "src/display/fetch_stream.js";
     libraryAlias["display-network"] = "src/display/network.js";
 
@@ -244,11 +239,8 @@ function createWebpackAlias(defines) {
     // Aliases defined here must also be replicated in the paths section of
     // the tsconfig.json file for the type generation to work.
     // In the tsconfig.json files, the .js extension must be omitted.
-    libraryAlias["display-cmap_reader_factory"] =
-      "src/display/cmap_reader_factory.js";
-    libraryAlias["display-standard_fontdata_factory"] =
-      "src/display/standard_fontdata_factory.js";
-    libraryAlias["display-wasm_factory"] = "src/display/wasm_factory.js";
+    libraryAlias["display-binary_data_factory"] =
+      "src/display/binary_data_factory.js";
     libraryAlias["display-fetch_stream"] = "src/display/fetch_stream.js";
     libraryAlias["display-network"] = "src/display/network.js";
     libraryAlias["display-node_stream"] = "src/display/node_stream.js";
@@ -1547,9 +1539,7 @@ function buildLibHelper(bundleDefines, inputStream, outputDir) {
     defines: bundleDefines,
     map: {
       "pdfjs-lib": "../pdf.js",
-      "display-cmap_reader_factory": "./cmap_reader_factory.js",
-      "display-standard_fontdata_factory": "./standard_fontdata_factory.js",
-      "display-wasm_factory": "./wasm_factory.js",
+      "display-binary_data_factory": "./binary_data_factory.js",
       "display-fetch_stream": "./fetch_stream.js",
       "display-network": "./network.js",
       "display-node_stream": "./node_stream.js",

src/core/evaluator.js

@@ -416,7 +416,7 @@ class PartialEvaluator {
       // Get the data on the main-thread instead.
       data = {
         cMapData: await this.handler.sendWithPromise("FetchBinaryData", {
-          type: "cMapReaderFactory",
+          kind: "cMapUrl",
           filename: `${name}${this.options.cMapPacked ? ".bcmap" : ""}`,
         }),
         isCompressed: this.options.cMapPacked,
@@ -459,7 +459,7 @@ class PartialEvaluator {
         }
         // Get the data on the main-thread instead.
         data = await this.handler.sendWithPromise("FetchBinaryData", {
-          type: "standardFontDataFactory",
+          kind: "standardFontDataUrl",
           filename,
         });
       }

src/core/jbig2_ccittFax_wasm.js

@@ -53,7 +53,7 @@ class JBig2CCITTFaxWasmImage {
           }
           this.#buffer = await this.#handler.sendWithPromise(
             "FetchBinaryData",
-            { type: "wasmFactory", filename }
+            { kind: "wasmUrl", filename }
           );
         }
       }

src/core/jpx.js

@@ -77,7 +77,7 @@ class JpxImage {
           }
           this.#buffer = await this.#handler.sendWithPromise(
             "FetchBinaryData",
-            { type: "wasmFactory", filename }
+            { kind: "wasmUrl", filename }
           );
         }
       }

src/display/api.js

@@ -66,18 +66,14 @@ import {
 } from "./api_utils.js";
 import { MessageHandler, wrapReason } from "../shared/message_handler.js";
 import {
+  NodeBinaryDataFactory,
   NodeCanvasFactory,
-  NodeCMapReaderFactory,
   NodeFilterFactory,
-  NodeStandardFontDataFactory,
-  NodeWasmFactory,
 } from "display-node_utils";
 import { CanvasGraphics } from "./canvas.js";
+import { DOMBinaryDataFactory } from "display-binary_data_factory";
 import { DOMCanvasFactory } from "./canvas_factory.js";
-import { DOMCMapReaderFactory } from "display-cmap_reader_factory";
 import { DOMFilterFactory } from "./filter_factory.js";
-import { DOMStandardFontDataFactory } from "display-standard_fontdata_factory";
-import { DOMWasmFactory } from "display-wasm_factory";
 import { GlobalWorkerOptions } from "./worker_options.js";
 import { initWebGPUMesh } from "./webgpu_mesh.js";
 import { Metadata } from "./metadata.js";
@@ -140,9 +136,6 @@ const RENDERING_CANCELLED_TIMEOUT = 100; // ms
  *   located. Include the trailing slash.
  * @property {boolean} [cMapPacked] - Specifies if the Adobe CMaps are binary
  *   packed or not. The default value is `true`.
- * @property {Object} [CMapReaderFactory] - The factory that will be used when
- *   reading built-in CMap files.
- *   The default value is {DOMCMapReaderFactory}.
  * @property {string} [iccUrl] - The URL where the predefined ICC profiles are
  *   located. Include the trailing slash.
  * @property {boolean} [useSystemFonts] - When `true`, fonts that aren't
@@ -152,18 +145,11 @@ const RENDERING_CANCELLED_TIMEOUT = 100; // ms
  *   regardless of the environment (to prevent completely broken fonts).
  * @property {string} [standardFontDataUrl] - The URL where the standard font
  *   files are located. Include the trailing slash.
- * @property {Object} [StandardFontDataFactory] - The factory that will be used
- *   when reading the standard font files.
- *   The default value is {DOMStandardFontDataFactory}.
  * @property {string} [wasmUrl] - The URL where the wasm files are located.
  *   Include the trailing slash.
- * @property {Object} [WasmFactory] - The factory that will be used
- *   when reading the wasm files.
- *   The default value is {DOMWasmFactory}.
  * @property {boolean} [useWorkerFetch] - Enable using the Fetch API in the
- *   worker-thread when reading CMap and standard font files. When `true`,
- *   the `CMapReaderFactory`, `StandardFontDataFactory`, and `WasmFactory`
- *   options are ignored.
+ *   worker-thread when reading built-in CMap files, standard font files,
+ *   and wasm files. If `true`, the `BinaryDataFactory` option is 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.
@@ -235,6 +221,10 @@ const RENDERING_CANCELLED_TIMEOUT = 100; // ms
  * @property {Object} [FilterFactory] - The factory that will be used to
  *    create SVG filters when rendering some images on the main canvas.
  *    The default value is {DOMFilterFactory}.
+ * @property {Object} [BinaryDataFactory] - The factory that will be used when
+ *   falling back to reading built-in CMap files, standard font files,
+ *   and wasm files in the main-thread.
+ *   The default value is {DOMBinaryDataFactory}.
  * @property {boolean} [enableHWA] - Enables hardware acceleration for
  *   rendering. The default value is `false`.
  * @property {Object} [pagesMapper] - The pages mapper that will be used to map
@@ -287,24 +277,9 @@ function getDocument(src = {}) {
       : null;
   const cMapUrl = getFactoryUrlProp(src.cMapUrl);
   const cMapPacked = src.cMapPacked !== false;
-  const CMapReaderFactory =
-    src.CMapReaderFactory ||
-    (typeof PDFJSDev !== "undefined" && PDFJSDev.test("GENERIC") && isNodeJS
-      ? NodeCMapReaderFactory
-      : DOMCMapReaderFactory);
   const iccUrl = getFactoryUrlProp(src.iccUrl);
   const standardFontDataUrl = getFactoryUrlProp(src.standardFontDataUrl);
-  const StandardFontDataFactory =
-    src.StandardFontDataFactory ||
-    (typeof PDFJSDev !== "undefined" && PDFJSDev.test("GENERIC") && isNodeJS
-      ? NodeStandardFontDataFactory
-      : DOMStandardFontDataFactory);
   const wasmUrl = getFactoryUrlProp(src.wasmUrl);
-  const WasmFactory =
-    src.WasmFactory ||
-    (typeof PDFJSDev !== "undefined" && PDFJSDev.test("GENERIC") && isNodeJS
-      ? NodeWasmFactory
-      : DOMWasmFactory);
   const ignoreErrors = src.stopAtErrors !== true;
   const maxImageSize =
     Number.isInteger(src.maxImageSize) && src.maxImageSize > -1
@@ -347,6 +322,11 @@ function getDocument(src = {}) {
     (typeof PDFJSDev !== "undefined" && PDFJSDev.test("GENERIC") && isNodeJS
       ? NodeFilterFactory
       : DOMFilterFactory);
+  const BinaryDataFactory =
+    src.BinaryDataFactory ||
+    (typeof PDFJSDev !== "undefined" && PDFJSDev.test("GENERIC") && isNodeJS
+      ? NodeBinaryDataFactory
+      : DOMBinaryDataFactory);
   const enableHWA = src.enableHWA === true;
   const enableWebGPU = src.enableWebGPU === true;
   const useWasm = src.useWasm !== false;
@@ -362,9 +342,7 @@ function getDocument(src = {}) {
       ? src.useWorkerFetch
       : (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
         !!(
-          CMapReaderFactory === DOMCMapReaderFactory &&
-          StandardFontDataFactory === DOMStandardFontDataFactory &&
-          WasmFactory === DOMWasmFactory &&
+          BinaryDataFactory === DOMBinaryDataFactory &&
           cMapUrl &&
           cMapPacked &&
           standardFontDataUrl &&
@@ -388,21 +366,11 @@ function getDocument(src = {}) {
   const transportFactory = {
     canvasFactory: new CanvasFactory({ ownerDocument, enableHWA }),
     filterFactory: new FilterFactory({ docId, ownerDocument }),
-    cMapReaderFactory:
+    binaryDataFactory:
       (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
       useWorkerFetch
         ? null
-        : new CMapReaderFactory({ baseUrl: cMapUrl }),
-    standardFontDataFactory:
-      (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
-      useWorkerFetch
-        ? null
-        : new StandardFontDataFactory({ baseUrl: standardFontDataUrl }),
-    wasmFactory:
-      (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
-      useWorkerFetch
-        ? null
-        : new WasmFactory({ baseUrl: wasmUrl }),
+        : new BinaryDataFactory({ cMapUrl, standardFontDataUrl, wasmUrl }),
   };
 
   if (!worker) {
@@ -2474,9 +2442,7 @@ class WorkerTransport {
     this.canvasFactory = factory.canvasFactory;
     this.filterFactory = factory.filterFactory;
     if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("MOZCENTRAL")) {
-      this.cMapReaderFactory = factory.cMapReaderFactory;
-      this.standardFontDataFactory = factory.standardFontDataFactory;
-      this.wasmFactory = factory.wasmFactory;
+      this.binaryDataFactory = factory.binaryDataFactory;
     }
     this.pagesMapper = pagesMapper;
 
@@ -2943,14 +2909,12 @@ class WorkerTransport {
         if (this.destroyed) {
           throw new Error("Worker was destroyed.");
         }
-        const factory = this[data.type];
-
-        if (!factory) {
+        if (!this.binaryDataFactory) {
           throw new Error(
-            `${data.type} not initialized, see the \`useWorkerFetch\` parameter.`
+            "`BinaryDataFactory` not initialized, see the `useWorkerFetch` parameter."
           );
         }
-        return factory.fetch(data);
+        return this.binaryDataFactory.fetch(data);
       });
     }
   }

src/display/binary_data_factory.js

@@ -0,0 +1,79 @@
+/* Copyright 2015 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { stringToBytes, unreachable } from "../shared/util.js";
+import { fetchData } from "./display_utils.js";
+
+class BaseBinaryDataFactory {
+  #errorStr = Object.freeze({
+    cMapUrl: "CMap",
+    standardFontDataUrl: "font",
+    wasmUrl: "wasm",
+  });
+
+  constructor({ cMapUrl = null, standardFontDataUrl = null, wasmUrl = null }) {
+    if (
+      (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) &&
+      this.constructor === BaseBinaryDataFactory
+    ) {
+      unreachable("Cannot initialize BaseBinaryDataFactory.");
+    }
+    this.cMapUrl = cMapUrl;
+    this.standardFontDataUrl = standardFontDataUrl;
+    this.wasmUrl = wasmUrl;
+  }
+
+  async fetch({ kind, filename }) {
+    switch (kind) {
+      case "cMapUrl":
+      case "standardFontDataUrl":
+      case "wasmUrl":
+        break;
+      default:
+        unreachable(`Not implemented: ${kind}`);
+    }
+    const baseUrl = this[kind];
+    if (!baseUrl) {
+      throw new Error(`Ensure that the \`${kind}\` API parameter is provided.`);
+    }
+    const url = `${baseUrl}${filename}`;
+
+    return this._fetch(url, kind).catch(reason => {
+      throw new Error(`Unable to load ${this.#errorStr[kind]} data at: ${url}`);
+    });
+  }
+
+  /**
+   * @ignore
+   * @returns {Promise<Uint8Array>}
+   */
+  async _fetch(url, kind) {
+    unreachable("Abstract method `_fetch` called.");
+  }
+}
+
+class DOMBinaryDataFactory extends BaseBinaryDataFactory {
+  /**
+   * @ignore
+   */
+  async _fetch(url, kind) {
+    const type =
+      kind === "cMapUrl" && !url.endsWith(".bcmap") ? "text" : "bytes";
+    const data = await fetchData(url, type);
+    return data instanceof Uint8Array ? data : stringToBytes(data);
+  }
+}
+
+export { BaseBinaryDataFactory, DOMBinaryDataFactory };