Re-factor how the GenericL10n class fetches localization-data

 - Re-factor the existing `fetchData` helper function such that it can fetch more types of data, and it now supports "arraybuffer", "json", and "text".
   This only needed minor adjustments in the `DOMCMapReaderFactory` and `DOMStandardFontDataFactory` classes.[1]

 - Expose the `fetchData` helper function in the API, such that the viewer is able to access it.

 - Use the `fetchData` helper function in the `GenericL10n` class, since this should allow fetching of localization-data even if the default viewer is run in an environment without support for the Fetch API.

---
[1] While testing this I also noticed a minor inconsistency when handling standard font-data on the worker-thread.

src/core/evaluator.js

@@ -425,7 +425,7 @@ class PartialEvaluator {
  `fetchStandardFontData: failed to fetch file "${url}" with "${response.statusText}".`
  );
  } else {
- data = await response.arrayBuffer();
+ data = new Uint8Array(await response.arrayBuffer());
  }
  } else {
  // Get the data on the main-thread instead.

src/display/display_utils.js

@@ -387,7 +387,7 @@ class DOMCanvasFactory extends BaseCanvasFactory {
  }
 }
 
-async function fetchData(url, asTypedArray = false) {
+async function fetchData(url, type = "text") {
  if (
  (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
  isValidFetchUrl(url, document.baseURI)
@@ -396,29 +396,35 @@ async function fetchData(url, asTypedArray = false) {
  if (!response.ok) {
  throw new Error(response.statusText);
  }
- return asTypedArray
- ? new Uint8Array(await response.arrayBuffer())
- : stringToBytes(await response.text());
+ switch (type) {
+ case "arraybuffer":
+ return response.arrayBuffer();
+ case "json":
+ return response.json();
+ }
+ return response.text();
  }
 
  // The Fetch API is not supported.
  return new Promise((resolve, reject) => {
  const request = new XMLHttpRequest();
- request.open("GET", url, /* asTypedArray = */ true);
+ request.open("GET", url, /* async = */ true);
+ request.responseType = type;
 
- if (asTypedArray) {
- request.responseType = "arraybuffer";
- }
  request.onreadystatechange = () => {
  if (request.readyState !== XMLHttpRequest.DONE) {
  return;
  }
  if (request.status === 200 || request.status === 0) {
  let data;
- if (asTypedArray && request.response) {
- data = new Uint8Array(request.response);
- } else if (!asTypedArray && request.responseText) {
- data = stringToBytes(request.responseText);
+ switch (type) {
+ case "arraybuffer":
+ case "json":
+ data = request.response;
+ break;
+ default:
+ data = request.responseText;
+ break;
  }
  if (data) {
  resolve(data);
@@ -437,8 +443,17 @@ class DOMCMapReaderFactory extends BaseCMapReaderFactory {
  * @ignore
  */
  _fetchData(url, compressionType) {
- return fetchData(url, /* asTypedArray = */ this.isCompressed).then(data => {
- return { cMapData: data, compressionType };
+ return fetchData(
+ url,
+ /* type = */ this.isCompressed ? "arraybuffer" : "text"
+ ).then(data => {
+ return {
+ cMapData:
+ data instanceof ArrayBuffer
+ ? new Uint8Array(data)
+ : stringToBytes(data),
+ compressionType,
+ };
  });
  }
 }
@@ -448,7 +463,9 @@ class DOMStandardFontDataFactory extends BaseStandardFontDataFactory {
  * @ignore
  */
  _fetchData(url) {
- return fetchData(url, /* asTypedArray = */ true);
+ return fetchData(url, /* type = */ "arraybuffer").then(data => {
+ return new Uint8Array(data);
+ });
  }
 }
 
@@ -993,6 +1010,7 @@ export {
  DOMFilterFactory,
  DOMStandardFontDataFactory,
  DOMSVGFactory,
+ fetchData,
  getColorValues,
  getCurrentTransform,
  getCurrentTransformInverse,

src/pdf.js

@@ -54,6 +54,7 @@ import {
 } from "./display/api.js";
 import {
  DOMSVGFactory,
+ fetchData,
  getFilenameFromUrl,
  getPdfFilenameFromUrl,
  getXfaPageViewport,
@@ -92,6 +93,7 @@ export {
  createValidAbsoluteUrl,
  DOMSVGFactory,
  FeatureTest,
+ fetchData,
  getDocument,
  getFilenameFromUrl,
  getPdfFilenameFromUrl,

test/unit/pdf_spec.js

@@ -44,6 +44,7 @@ import {
 } from "../../src/display/api.js";
 import {
  DOMSVGFactory,
+ fetchData,
  getFilenameFromUrl,
  getPdfFilenameFromUrl,
  getXfaPageViewport,
@@ -78,6 +79,7 @@ const expectedAPI = Object.freeze({
  createValidAbsoluteUrl,
  DOMSVGFactory,
  FeatureTest,
+ fetchData,
  getDocument,
  getFilenameFromUrl,
  getPdfFilenameFromUrl,

web/genericl10n.js

@@ -17,6 +17,7 @@
 
 import { FluentBundle, FluentResource } from "fluent-bundle";
 import { DOMLocalization } from "fluent-dom";
+import { fetchData } from "pdfjs-lib";
 import { L10n } from "./l10n.js";
 
 /**
@@ -71,8 +72,8 @@ class GenericL10n extends L10n {
  return null;
  }
  const url = new URL(path, baseURL);
- const data = await fetch(url);
- const text = await data.text();
+ const text = await fetchData(url, /* type = */ "text");
+
  const resource = new FluentResource(text);
  const bundle = new FluentBundle(lang);
  const errors = bundle.addResource(resource);
@@ -84,8 +85,8 @@ class GenericL10n extends L10n {
 
  static async #getPaths() {
  const { href } = document.querySelector(`link[type="application/l10n"]`);
- const data = await fetch(href);
- const paths = await data.json();
+ const paths = await fetchData(href, /* type = */ "json");
+
  return { baseURL: href.replace(/[^/]*$/, "") || "./", paths };
  }
 }

web/pdfjs.js

@@ -35,6 +35,7 @@ const {
  createValidAbsoluteUrl,
  DOMSVGFactory,
  FeatureTest,
+ fetchData,
  getDocument,
  getFilenameFromUrl,
  getPdfFilenameFromUrl,
@@ -80,6 +81,7 @@ export {
  createValidAbsoluteUrl,
  DOMSVGFactory,
  FeatureTest,
+ fetchData,
  getDocument,
  getFilenameFromUrl,
  getPdfFilenameFromUrl,