[api-minor] Re-factor how Node.js packages/polyfills are loaded (issue 17245)

gulpfile.mjs

@@ -445,10 +445,8 @@ function checkChromePreferencesFile(chromePrefsPath, webPrefs) {
 
 function tweakWebpackOutput(jsName) {
   const replacer = [
-    " __webpack_exports__ = {};",
-    ",__webpack_exports__={};",
-    " __webpack_exports__ = await __webpack_exports__;",
-    "\\(__webpack_exports__=await __webpack_exports__\\)",
+    " __webpack_exports__ = {};", // Normal builds.
+    ",__webpack_exports__={};", // Minified builds.
   ];
   const regex = new RegExp(`(${replacer.join("|")})`, "gm");
 
@@ -458,10 +456,6 @@ function tweakWebpackOutput(jsName) {
         return ` __webpack_exports__ = globalThis.${jsName} = {};`;
       case ",__webpack_exports__={};":
         return `,__webpack_exports__=globalThis.${jsName}={};`;
-      case " __webpack_exports__ = await __webpack_exports__;":
-        return ` __webpack_exports__ = globalThis.${jsName} = await (globalThis.${jsName}Promise = __webpack_exports__);`;
-      case "(__webpack_exports__=await __webpack_exports__)":
-        return `(__webpack_exports__=globalThis.${jsName}=await (globalThis.${jsName}Promise=__webpack_exports__))`;
     }
     return match;
   });

src/display/api.js

@@ -58,6 +58,7 @@ import {
   NodeCanvasFactory,
   NodeCMapReaderFactory,
   NodeFilterFactory,
+  NodePackages,
   NodeStandardFontDataFactory,
 } from "display-node_utils";
 import { CanvasGraphics } from "./canvas.js";
@@ -2089,6 +2090,14 @@ class PDFWorker {
    * @type {Promise<void>}
    */
   get promise() {
+    if (
+      typeof PDFJSDev !== "undefined" &&
+      PDFJSDev.test("GENERIC") &&
+      isNodeJS
+    ) {
+      // Ensure that all Node.js packages/polyfills have loaded.
+      return Promise.all([NodePackages.promise, this._readyCapability.promise]);
+    }
     return this._readyCapability.promise;
   }
 

src/display/node_stream.js

@@ -13,35 +13,23 @@
  * limitations under the License.
  */
 
-import {
-  AbortException,
-  assert,
-  isNodeJS,
-  MissingPDFException,
-} from "../shared/util.js";
+import { AbortException, assert, MissingPDFException } from "../shared/util.js";
 import {
   extractFilenameFromHeader,
   validateRangeRequestCapabilities,
 } from "./network_utils.js";
+import { NodePackages } from "./node_utils.js";
 
 if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
   throw new Error(
     'Module "./node_stream.js" shall not be used with MOZCENTRAL builds.'
   );
 }
 
-let fs, http, https, url;
-if (isNodeJS) {
-  // Native packages.
-  fs = await __non_webpack_import__("fs");
-  http = await __non_webpack_import__("http");
-  https = await __non_webpack_import__("https");
-  url = await __non_webpack_import__("url");
-}
-
 const fileUriRegex = /^file:\/\/\/[a-zA-Z]:\//;
 
 function parseUrl(sourceUrl) {
+  const url = NodePackages.get("url");
   const parsedUrl = url.parse(sourceUrl);
   if (parsedUrl.protocol === "file:" || parsedUrl.host) {
     return parsedUrl;
@@ -347,11 +335,13 @@ class PDFNodeStreamFullReader extends BaseFullReader {
 
     this._request = null;
     if (this._url.protocol === "http:") {
+      const http = NodePackages.get("http");
       this._request = http.request(
         createRequestOptions(this._url, stream.httpHeaders),
         handleResponse
       );
     } else {
+      const https = NodePackages.get("https");
       this._request = https.request(
         createRequestOptions(this._url, stream.httpHeaders),
         handleResponse
@@ -394,11 +384,13 @@ class PDFNodeStreamRangeReader extends BaseRangeReader {
 
     this._request = null;
     if (this._url.protocol === "http:") {
+      const http = NodePackages.get("http");
       this._request = http.request(
         createRequestOptions(this._url, this._httpHeaders),
         handleResponse
       );
     } else {
+      const https = NodePackages.get("https");
       this._request = https.request(
         createRequestOptions(this._url, this._httpHeaders),
         handleResponse
@@ -423,6 +415,7 @@ class PDFNodeStreamFsFullReader extends BaseFullReader {
       path = path.replace(/^\//, "");
     }
 
+    const fs = NodePackages.get("fs");
     fs.promises.lstat(path).then(
       stat => {
         // Setting right content length.
@@ -453,6 +446,7 @@ class PDFNodeStreamFsRangeReader extends BaseRangeReader {
       path = path.replace(/^\//, "");
     }
 
+    const fs = NodePackages.get("fs");
     this._setReadableStream(fs.createReadStream(path, { start, end: end - 1 }));
   }
 }

src/display/node_utils.js

@@ -27,56 +27,90 @@ if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
   );
 }
 
-let fs, canvas, path2d;
 if (isNodeJS) {
-  // Native packages.
-  fs = await __non_webpack_import__("fs");
-  // Optional, third-party, packages.
-  try {
-    canvas = await __non_webpack_import__("canvas");
-  } catch {}
-  try {
-    path2d = await __non_webpack_import__("path2d");
-  } catch {}
-}
+  // eslint-disable-next-line no-var
+  var packageCapability = Promise.withResolvers();
+  // eslint-disable-next-line no-var
+  var packageMap = null;
 
-if (typeof PDFJSDev !== "undefined" && !PDFJSDev.test("SKIP_BABEL")) {
-  (function checkDOMMatrix() {
-    if (globalThis.DOMMatrix || !isNodeJS) {
-      return;
-    }
-    const DOMMatrix = canvas?.DOMMatrix;
+  const loadPackages = async () => {
+    // Native packages.
+    const fs = await __non_webpack_import__("fs"),
+      http = await __non_webpack_import__("http"),
+      https = await __non_webpack_import__("https"),
+      url = await __non_webpack_import__("url");
 
-    if (DOMMatrix) {
-      globalThis.DOMMatrix = DOMMatrix;
-    } else {
-      warn("Cannot polyfill `DOMMatrix`, rendering may be broken.");
+    // Optional, third-party, packages.
+    let canvas, path2d;
+    if (typeof PDFJSDev !== "undefined" && !PDFJSDev.test("SKIP_BABEL")) {
+      try {
+        canvas = await __non_webpack_import__("canvas");
+      } catch {}
+      try {
+        path2d = await __non_webpack_import__("path2d");
+      } catch {}
     }
-  })();
 
-  (function checkPath2D() {
-    if (globalThis.Path2D || !isNodeJS) {
-      return;
-    }
-    const CanvasRenderingContext2D = canvas?.CanvasRenderingContext2D;
-    const applyPath2DToCanvasRenderingContext =
-      path2d?.applyPath2DToCanvasRenderingContext;
-    const Path2D = path2d?.Path2D;
-
-    if (
-      CanvasRenderingContext2D &&
-      applyPath2DToCanvasRenderingContext &&
-      Path2D
-    ) {
-      applyPath2DToCanvasRenderingContext(CanvasRenderingContext2D);
-      globalThis.Path2D = Path2D;
-    } else {
-      warn("Cannot polyfill `Path2D`, rendering may be broken.");
+    return new Map(Object.entries({ fs, http, https, url, canvas, path2d }));
+  };
+
+  loadPackages().then(
+    map => {
+      packageMap = map;
+      packageCapability.resolve();
+
+      if (typeof PDFJSDev === "undefined" || PDFJSDev.test("SKIP_BABEL")) {
+        return;
+      }
+      if (!globalThis.DOMMatrix) {
+        const DOMMatrix = map.get("canvas")?.DOMMatrix;
+
+        if (DOMMatrix) {
+          globalThis.DOMMatrix = DOMMatrix;
+        } else {
+          warn("Cannot polyfill `DOMMatrix`, rendering may be broken.");
+        }
+      }
+      if (!globalThis.Path2D) {
+        const CanvasRenderingContext2D =
+          map.get("canvas")?.CanvasRenderingContext2D;
+        const applyPath2DToCanvasRenderingContext =
+          map.get("path2d")?.applyPath2DToCanvasRenderingContext;
+        const Path2D = map.get("path2d")?.Path2D;
+
+        if (
+          CanvasRenderingContext2D &&
+          applyPath2DToCanvasRenderingContext &&
+          Path2D
+        ) {
+          applyPath2DToCanvasRenderingContext(CanvasRenderingContext2D);
+          globalThis.Path2D = Path2D;
+        } else {
+          warn("Cannot polyfill `Path2D`, rendering may be broken.");
+        }
+      }
+    },
+    reason => {
+      warn(`loadPackages: ${reason}`);
+
+      packageMap = new Map();
+      packageCapability.resolve();
     }
-  })();
+  );
+}
+
+class NodePackages {
+  static get promise() {
+    return packageCapability.promise;
+  }
+
+  static get(name) {
+    return packageMap?.get(name);
+  }
 }
 
 const fetchData = function (url) {
+  const fs = NodePackages.get("fs");
   return fs.promises.readFile(url).then(data => new Uint8Array(data));
 };
 
@@ -87,6 +121,7 @@ class NodeCanvasFactory extends BaseCanvasFactory {
    * @ignore
    */
   _createCanvas(width, height) {
+    const canvas = NodePackages.get("canvas");
     return canvas.createCanvas(width, height);
   }
 }
@@ -113,5 +148,6 @@ export {
   NodeCanvasFactory,
   NodeCMapReaderFactory,
   NodeFilterFactory,
+  NodePackages,
   NodeStandardFontDataFactory,
 };

src/display/stubs.js

@@ -16,6 +16,7 @@
 const NodeCanvasFactory = null;
 const NodeCMapReaderFactory = null;
 const NodeFilterFactory = null;
+const NodePackages = null;
 const NodeStandardFontDataFactory = null;
 const PDFFetchStream = null;
 const PDFNetworkStream = null;
@@ -25,6 +26,7 @@ export {
   NodeCanvasFactory,
   NodeCMapReaderFactory,
   NodeFilterFactory,
+  NodePackages,
   NodeStandardFontDataFactory,
   PDFFetchStream,
   PDFNetworkStream,

test/unit/clitests_helper.js

@@ -18,6 +18,7 @@ import {
   setVerbosityLevel,
   VerbosityLevel,
 } from "../../src/shared/util.js";
+import { NodePackages } from "../../src/display/node_utils.js";
 
 // Sets longer timeout, similar to `jasmine-boot.js`.
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 30000;
@@ -29,6 +30,9 @@ if (!isNodeJS) {
   );
 }
 
+// Ensure that all Node.js packages/polyfills have loaded.
+await NodePackages.promise;
+
 // Reduce the amount of console "spam", by ignoring `info`/`warn` calls,
 // when running the unit-tests in Node.js/Travis.
 setVerbosityLevel(VerbosityLevel.ERRORS);

web/pdfjs.js

@@ -13,15 +13,6 @@
  * limitations under the License.
  */
 
-// Ensure that the viewer waits for the library to complete loading,
-// to avoid breaking e.g. the standalone viewer components (see issue 17228).
-if (
-  (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) &&
-  !globalThis.pdfjsLib
-) {
-  await globalThis.pdfjsLibPromise;
-}
-
 const {
   AbortException,
   AnnotationEditorLayer,