[api-minor] Simplify the *fallback* fake worker loader code in src/display/api.js

examples/browserify/main.js

@@ -5,7 +5,7 @@
 
 var pdfjsLib = require('pdfjs-dist');
 
-var pdfPath = '../helloworld/helloworld.pdf';
+var pdfPath = '../learning/helloworld.pdf';
 
 // Setting worker path to worker bundle.
 pdfjsLib.GlobalWorkerOptions.workerSrc =

examples/webpack/main.js

@@ -5,7 +5,7 @@
 
 var pdfjsLib = require('pdfjs-dist');
 
-var pdfPath = '../helloworld/helloworld.pdf';
+var pdfPath = '../learning/helloworld.pdf';
 
 // Setting worker path to worker bundle.
 pdfjsLib.GlobalWorkerOptions.workerSrc =

gulpfile.js

@@ -1320,7 +1320,6 @@ gulp.task('dist-pre', gulp.series('generic', 'components', 'image_decoders',
  bugs: DIST_BUGS_URL,
  license: DIST_LICENSE,
  dependencies: {
- 'node-ensure': '^0.0.0', // shim for node for require.ensure
  'worker-loader': '^2.0.0', // used in external/dist/webpack.json
  },
  peerDependencies: {
@@ -1330,7 +1329,6 @@ gulp.task('dist-pre', gulp.series('generic', 'components', 'image_decoders',
  'fs': false,
  'http': false,
  'https': false,
- 'node-ensure': false,
  'url': false,
  'zlib': false,
  },

package.json

@@ -35,7 +35,6 @@
  "jstransformer-markdown-it": "^2.1.0",
  "merge-stream": "^1.0.1",
  "mkdirp": "^0.5.1",
- "node-ensure": "^0.0.0",
  "prettier": "^1.19.1",
  "rimraf": "^2.7.1",
  "streamqueue": "^1.1.2",

src/display/api.js

@@ -12,7 +12,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-/* globals requirejs, __non_webpack_require__ */
 /* eslint no-var: error */
 
 /**
@@ -27,13 +26,14 @@ import {
  unreachable, warn
 } from '../shared/util';
 import {
- DOMCanvasFactory, DOMCMapReaderFactory, loadScript, PageViewport,
+ deprecated, DOMCanvasFactory, DOMCMapReaderFactory, loadScript, PageViewport,
  releaseImageResources, RenderingCancelledException, StatTimer
 } from './display_utils';
 import { FontFaceObject, FontLoader } from './font_loader';
 import { apiCompatibilityParams } from './api_compatibility';
 import { CanvasGraphics } from './canvas';
 import { GlobalWorkerOptions } from './worker_options';
+import { isNodeJS } from '../shared/is_node';
 import { MessageHandler } from '../shared/message_handler';
 import { Metadata } from './metadata';
 import { PDFDataTransportStream } from './transport_stream';
@@ -42,68 +42,6 @@ import { WebGLContext } from './webgl';
 const DEFAULT_RANGE_CHUNK_SIZE = 65536; // 2^16 = 65536
 const RENDERING_CANCELLED_TIMEOUT = 100; // ms
 
-let isWorkerDisabled = false;
-let fallbackWorkerSrc;
-
-let fakeWorkerFilesLoader = null;
-if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('GENERIC')) {
- let useRequireEnsure = false;
- // For GENERIC build we need to add support for different fake file loaders
- // for different frameworks.
- if (typeof window === 'undefined') {
- // node.js - disable worker and set require.ensure.
- isWorkerDisabled = true;
- if (typeof __non_webpack_require__.ensure === 'undefined') {
- __non_webpack_require__.ensure = __non_webpack_require__('node-ensure');
- }
- useRequireEnsure = true;
- } else if (typeof __non_webpack_require__ !== 'undefined' &&
- typeof __non_webpack_require__.ensure === 'function') {
- useRequireEnsure = true;
- }
- if (typeof requirejs !== 'undefined' && requirejs.toUrl) {
- fallbackWorkerSrc = requirejs.toUrl('pdfjs-dist/build/pdf.worker.js');
- }
- const dynamicLoaderSupported =
- typeof requirejs !== 'undefined' && requirejs.load;
- fakeWorkerFilesLoader = useRequireEnsure ? (function() {
- return new Promise(function(resolve, reject) {
- __non_webpack_require__.ensure([], function() {
- try {
- let worker;
- if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('LIB')) {
- worker = __non_webpack_require__('../pdf.worker.js');
- } else {
- worker = __non_webpack_require__('./pdf.worker.js');
- }
- resolve(worker.WorkerMessageHandler);
- } catch (ex) {
- reject(ex);
- }
- }, reject, 'pdfjsWorker');
- });
- }) : dynamicLoaderSupported ? (function() {
- return new Promise(function(resolve, reject) {
- requirejs(['pdfjs-dist/build/pdf.worker'], function(worker) {
- try {
- resolve(worker.WorkerMessageHandler);
- } catch (ex) {
- reject(ex);
- }
- }, reject);
- });
- }) : null;
-
- if (!fallbackWorkerSrc && typeof document === 'object' &&
- 'currentScript' in document) {
- const pdfjsFilePath = document.currentScript && document.currentScript.src;
- if (pdfjsFilePath) {
- fallbackWorkerSrc =
- pdfjsFilePath.replace(/(\.(?:min\.)?js)(\?.*)?$/i, '.worker$1$2');
- }
- }
-}
-
 /**
  * @typedef {function} IPDFStreamFactory
  * @param {DocumentInitParameters} params The document initialization
@@ -1526,14 +1464,40 @@ class LoopbackPort {
 
 const PDFWorker = (function PDFWorkerClosure() {
  const pdfWorkerPorts = new WeakMap();
+ let isWorkerDisabled = false;
+ let fallbackWorkerSrc;
  let nextFakeWorkerId = 0;
- let fakeWorkerFilesLoadedCapability;
+ 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;
+
+ if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('LIB')) {
+ fallbackWorkerSrc = '../pdf.worker.js';
+ } else {
+ fallbackWorkerSrc = './pdf.worker.js';
+ }
+ } else if (typeof document === 'object' && 'currentScript' in document) {
+ const pdfjsFilePath = document.currentScript &&
+ document.currentScript.src;
+ if (pdfjsFilePath) {
+ fallbackWorkerSrc =
+ pdfjsFilePath.replace(/(\.(?:min\.)?js)(\?.*)?$/i, '.worker$1$2');
+ }
+ }
+ }
 
  function getWorkerSrc() {
  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.');
@@ -1550,39 +1514,50 @@ const PDFWorker = (function PDFWorkerClosure() {
 
  // Loads worker code into main thread.
  function setupFakeWorkerGlobal() {
- if (fakeWorkerFilesLoadedCapability) {
- return fakeWorkerFilesLoadedCapability.promise;
- }
- fakeWorkerFilesLoadedCapability = createPromiseCapability();
-
- const mainWorkerMessageHandler = getMainThreadWorkerMessageHandler();
- if (mainWorkerMessageHandler) {
- // The worker was already loaded using a `<script>` tag.
- fakeWorkerFilesLoadedCapability.resolve(mainWorkerMessageHandler);
- return fakeWorkerFilesLoadedCapability.promise;
- }
- // In the developer build load worker_loader.js which in turn loads all the
- // other files and resolves the promise. In production only the
- // pdf.worker.js file is needed.
- if (typeof PDFJSDev === 'undefined' || !PDFJSDev.test('PRODUCTION')) {
- if (typeof SystemJS === 'object') {
- SystemJS.import('pdfjs/core/worker').then((worker) => {
- fakeWorkerFilesLoadedCapability.resolve(worker.WorkerMessageHandler);
- }).catch(fakeWorkerFilesLoadedCapability.reject);
- } else {
- fakeWorkerFilesLoadedCapability.reject(
- new Error('SystemJS must be used to load fake worker.'));
- }
- } else {
- const loader = fakeWorkerFilesLoader || function() {
- return loadScript(getWorkerSrc()).then(function() {
- return window.pdfjsWorker.WorkerMessageHandler;
- });
- };
- loader().then(fakeWorkerFilesLoadedCapability.resolve,
- fakeWorkerFilesLoadedCapability.reject);
+ if (fakeWorkerCapability) {
+ return fakeWorkerCapability.promise;
  }
- return fakeWorkerFilesLoadedCapability.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')) {
+ if (typeof SystemJS !== 'object') {
+ throw new Error('SystemJS must be used to load fake worker.');
+ }
+ const worker = await SystemJS.import('pdfjs/core/worker');
+ return worker.WorkerMessageHandler;
+ }
+ if ((typeof PDFJSDev !== 'undefined' && PDFJSDev.test('GENERIC')) &&
+ // eslint-disable-next-line no-undef
+ (isNodeJS && 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) {

web/app.js

@@ -1523,21 +1523,16 @@ if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC')) {
  };
 }
 
-function loadFakeWorker() {
+async function loadFakeWorker() {
  if (!GlobalWorkerOptions.workerSrc) {
  GlobalWorkerOptions.workerSrc = AppOptions.get('workerSrc');
  }
  if (typeof PDFJSDev === 'undefined' || !PDFJSDev.test('PRODUCTION')) {
- return new Promise(function(resolve, reject) {
- if (typeof SystemJS === 'object') {
- SystemJS.import('pdfjs/core/worker').then((worker) => {
- window.pdfjsWorker = worker;
- resolve();
- }).catch(reject);
- } else {
- reject(new Error('SystemJS must be used to load fake worker.'));
- }
- });
+ if (typeof SystemJS !== 'object') {
+ throw new Error('SystemJS must be used to load fake worker.');
+ }
+ window.pdfjsWorker = await SystemJS.import('pdfjs/core/worker');
+ return undefined;
  }
  return loadScript(PDFWorker.getWorkerSrc());
 }