[api-minor] Use the NodeCanvasFactory/NodeCMapReaderFactory classes as defaults in Node.js environments (issue 11900)

This moves, and slightly simplifies, code that's currently residing in the unit-test utils into the actual library, such that it's bundled with `GENERIC`-builds and used in e.g. the API-code.

As an added bonus, this also brings out-of-the-box support for CMaps in e.g. the Node.js examples.

examples/node/pdf2png/pdf2png.js

@@ -50,14 +50,21 @@ NodeCanvasFactory.prototype = {
 
 var pdfjsLib = require("pdfjs-dist/es5/build/pdf.js");
 
-// Relative path of the PDF file.
-var pdfURL = "../../../web/compressed.tracemonkey-pldi-09.pdf";
+// Some PDFs need external cmaps.
+var CMAP_URL = "../../../node_modules/pdfjs-dist/cmaps/";
+var CMAP_PACKED = true;
 
-// Read the PDF file into a typed array so PDF.js can load it.
-var rawData = new Uint8Array(fs.readFileSync(pdfURL));
+// Loading file from file system into typed array.
+var pdfPath =
+  process.argv[2] || "../../../web/compressed.tracemonkey-pldi-09.pdf";
+var data = new Uint8Array(fs.readFileSync(pdfPath));
 
 // Load the PDF file.
-var loadingTask = pdfjsLib.getDocument(rawData);
+var loadingTask = pdfjsLib.getDocument({
+  data: data,
+  cMapUrl: CMAP_URL,
+  cMapPacked: CMAP_PACKED,
+});
 loadingTask.promise
   .then(function (pdfDocument) {
     console.log("# PDF document loaded.");

examples/node/pdf2svg.js

@@ -16,6 +16,10 @@ require("./domstubs.js").setStubs(global);
 // Run `gulp dist-install` to generate 'pdfjs-dist' npm package files.
 var pdfjsLib = require("pdfjs-dist/es5/build/pdf.js");
 
+// Some PDFs need external cmaps.
+var CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
+var CMAP_PACKED = true;
+
 // Loading file from file system into typed array
 var pdfPath = process.argv[2] || "../../web/compressed.tracemonkey-pldi-09.pdf";
 var data = new Uint8Array(fs.readFileSync(pdfPath));
@@ -86,6 +90,8 @@ function writeSvgToFile(svgElement, filePath) {
 // callback.
 var loadingTask = pdfjsLib.getDocument({
   data: data,
+  cMapUrl: CMAP_URL,
+  cMapPacked: CMAP_PACKED,
   fontExtraProperties: true,
 });
 loadingTask.promise

gulpfile.js

@@ -1617,6 +1617,7 @@ gulp.task(
         bugs: DIST_BUGS_URL,
         license: DIST_LICENSE,
         browser: {
+          canvas: false,
           fs: false,
           http: false,
           https: false,

src/display/api.js

@@ -47,6 +47,7 @@ import {
   StatTimer,
 } from "./display_utils.js";
 import { FontFaceObject, FontLoader } from "./font_loader.js";
+import { NodeCanvasFactory, NodeCMapReaderFactory } from "./node_utils.js";
 import { apiCompatibilityParams } from "./api_compatibility.js";
 import { CanvasGraphics } from "./canvas.js";
 import { GlobalWorkerOptions } from "./worker_options.js";
@@ -59,6 +60,15 @@ import { WebGLContext } from "./webgl.js";
 const DEFAULT_RANGE_CHUNK_SIZE = 65536; // 2^16 = 65536
 const RENDERING_CANCELLED_TIMEOUT = 100; // ms
 
+const DefaultCanvasFactory =
+  (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) && isNodeJS
+    ? NodeCanvasFactory
+    : DOMCanvasFactory;
+const DefaultCMapReaderFactory =
+  (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) && isNodeJS
+    ? NodeCMapReaderFactory
+    : DOMCMapReaderFactory;
+
 /**
  * @typedef {function} IPDFStreamFactory
  * @param {DocumentInitParameters} params - The document initialization
@@ -242,7 +252,8 @@ function getDocument(src) {
   }
 
   params.rangeChunkSize = params.rangeChunkSize || DEFAULT_RANGE_CHUNK_SIZE;
-  params.CMapReaderFactory = params.CMapReaderFactory || DOMCMapReaderFactory;
+  params.CMapReaderFactory =
+    params.CMapReaderFactory || DefaultCMapReaderFactory;
   params.ignoreErrors = params.stopAtErrors !== true;
   params.fontExtraProperties = params.fontExtraProperties === true;
   params.pdfBug = params.pdfBug === true;
@@ -863,9 +874,9 @@ class PDFDocumentProxy {
  *                    just before viewport transform.
  * @property {Object} [imageLayer] - An object that has beginLayout,
  *                    endLayout and appendImage functions.
- * @property {Object} [canvasFactory] - The factory that will be used
+ * @property {Object} [canvasFactory] - The factory instance that will be used
  *                    when creating canvases. The default value is
- *                    {DOMCanvasFactory}.
+ *                    {new DOMCanvasFactory()}.
  * @property {Object} [background] - Background to use for the canvas.
  *                    Can use any valid canvas.fillStyle: A DOMString parsed as
  *                    CSS <color> value, a CanvasGradient object (a linear or
@@ -1015,7 +1026,7 @@ class PDFPageProxy {
       intentState.streamReaderCancelTimeout = null;
     }
 
-    const canvasFactoryInstance = canvasFactory || new DOMCanvasFactory();
+    const canvasFactoryInstance = canvasFactory || new DefaultCanvasFactory();
     const webGLContext = new WebGLContext({
       enable: enableWebGL,
     });

src/display/display_utils.js

@@ -21,6 +21,7 @@ import {
   isString,
   removeNullCharacters,
   stringToBytes,
+  unreachable,
   Util,
   warn,
 } from "../shared/util.js";
@@ -28,19 +29,15 @@ import {
 const DEFAULT_LINK_REL = "noopener noreferrer nofollow";
 const SVG_NS = "http://www.w3.org/2000/svg";
 
-class DOMCanvasFactory {
-  create(width, height) {
-    if (width <= 0 || height <= 0) {
-      throw new Error("Invalid canvas size");
+class BaseCanvasFactory {
+  constructor() {
+    if (this.constructor === BaseCanvasFactory) {
+      unreachable("Cannot initialize BaseCanvasFactory.");
     }
-    const canvas = document.createElement("canvas");
-    const context = canvas.getContext("2d");
-    canvas.width = width;
-    canvas.height = height;
-    return {
-      canvas,
-      context,
-    };
+  }
+
+  create(width, height) {
+    unreachable("Abstract method `create` called.");
   }
 
   reset(canvasAndContext, width, height) {
@@ -67,8 +64,27 @@ class DOMCanvasFactory {
   }
 }
 
-class DOMCMapReaderFactory {
+class DOMCanvasFactory extends BaseCanvasFactory {
+  create(width, height) {
+    if (width <= 0 || height <= 0) {
+      throw new Error("Invalid canvas size");
+    }
+    const canvas = document.createElement("canvas");
+    const context = canvas.getContext("2d");
+    canvas.width = width;
+    canvas.height = height;
+    return {
+      canvas,
+      context,
+    };
+  }
+}
+
+class BaseCMapReaderFactory {
   constructor({ baseUrl = null, isCompressed = false }) {
+    if (this.constructor === BaseCMapReaderFactory) {
+      unreachable("Cannot initialize BaseCMapReaderFactory.");
+    }
     this.baseUrl = baseUrl;
     this.isCompressed = isCompressed;
   }
@@ -88,29 +104,39 @@ class DOMCMapReaderFactory {
       ? CMapCompressionType.BINARY
       : CMapCompressionType.NONE;
 
+    return this._fetchData(url, compressionType).catch(reason => {
+      throw new Error(
+        `Unable to load ${this.isCompressed ? "binary " : ""}CMap at: ${url}`
+      );
+    });
+  }
+
+  /**
+   * @private
+   */
+  _fetchData(url, compressionType) {
+    unreachable("Abstract method `_fetchData` called.");
+  }
+}
+
+class DOMCMapReaderFactory extends BaseCMapReaderFactory {
+  _fetchData(url, compressionType) {
     if (
       (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
       (isFetchSupported() && isValidFetchUrl(url, document.baseURI))
     ) {
-      return fetch(url)
-        .then(async response => {
-          if (!response.ok) {
-            throw new Error(response.statusText);
-          }
-          let cMapData;
-          if (this.isCompressed) {
-            cMapData = new Uint8Array(await response.arrayBuffer());
-          } else {
-            cMapData = stringToBytes(await response.text());
-          }
-          return { cMapData, compressionType };
-        })
-        .catch(reason => {
-          throw new Error(
-            `Unable to load ${this.isCompressed ? "binary " : ""}` +
-              `CMap at: ${url}`
-          );
-        });
+      return fetch(url).then(async response => {
+        if (!response.ok) {
+          throw new Error(response.statusText);
+        }
+        let cMapData;
+        if (this.isCompressed) {
+          cMapData = new Uint8Array(await response.arrayBuffer());
+        } else {
+          cMapData = stringToBytes(await response.text());
+        }
+        return { cMapData, compressionType };
+      });
     }
 
     // The Fetch API is not supported.
@@ -141,11 +167,6 @@ class DOMCMapReaderFactory {
       };
 
       request.send(null);
-    }).catch(reason => {
-      throw new Error(
-        `Unable to load ${this.isCompressed ? "binary " : ""}` +
-          `CMap at: ${url}`
-      );
     });
   }
 }
@@ -609,7 +630,9 @@ export {
   getFilenameFromUrl,
   LinkTarget,
   DEFAULT_LINK_REL,
+  BaseCanvasFactory,
   DOMCanvasFactory,
+  BaseCMapReaderFactory,
   DOMCMapReaderFactory,
   DOMSVGFactory,
   StatTimer,

src/display/node_utils.js

@@ -0,0 +1,65 @@
+/* Copyright 2020 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.
+ */
+/* globals __non_webpack_require__ */
+/* eslint no-var: error */
+
+import { BaseCanvasFactory, BaseCMapReaderFactory } from "./display_utils.js";
+import { isNodeJS } from "../shared/is_node.js";
+import { unreachable } from "../shared/util.js";
+
+let NodeCanvasFactory = class {
+  constructor() {
+    unreachable("Not implemented: NodeCanvasFactory");
+  }
+};
+
+let NodeCMapReaderFactory = class {
+  constructor() {
+    unreachable("Not implemented: NodeCMapReaderFactory");
+  }
+};
+
+if ((typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) && isNodeJS) {
+  NodeCanvasFactory = class extends BaseCanvasFactory {
+    create(width, height) {
+      if (width <= 0 || height <= 0) {
+        throw new Error("Invalid canvas size");
+      }
+      const Canvas = __non_webpack_require__("canvas");
+      const canvas = Canvas.createCanvas(width, height);
+      return {
+        canvas,
+        context: canvas.getContext("2d"),
+      };
+    }
+  };
+
+  NodeCMapReaderFactory = class extends BaseCMapReaderFactory {
+    _fetchData(url, compressionType) {
+      return new Promise((resolve, reject) => {
+        const fs = __non_webpack_require__("fs");
+        fs.readFile(url, (error, data) => {
+          if (error || !data) {
+            reject(new Error(error));
+            return;
+          }
+          resolve({ cMapData: new Uint8Array(data), compressionType });
+        });
+      });
+    }
+  };
+}
+
+export { NodeCanvasFactory, NodeCMapReaderFactory };

test/unit/api_spec.js

@@ -16,7 +16,6 @@
 import {
   buildGetDocumentParams,
   DOMFileReaderFactory,
-  NodeCanvasFactory,
   NodeFileReaderFactory,
   TEST_PDFS_PATH,
 } from "./test_utils.js";
@@ -49,6 +48,7 @@ import { GlobalImageCache } from "../../src/core/image_utils.js";
 import { GlobalWorkerOptions } from "../../src/display/worker_options.js";
 import { isNodeJS } from "../../src/shared/is_node.js";
 import { Metadata } from "../../src/display/metadata.js";
+import { NodeCanvasFactory } from "../../src/display/node_utils.js";
 
 describe("api", function () {
   const basicApiFileName = "basicapi.pdf";

test/unit/cmap_spec.js

@@ -17,7 +17,7 @@ import { CMap, CMapFactory, IdentityCMap } from "../../src/core/cmap.js";
 import { DOMCMapReaderFactory } from "../../src/display/display_utils.js";
 import { isNodeJS } from "../../src/shared/is_node.js";
 import { Name } from "../../src/core/primitives.js";
-import { NodeCMapReaderFactory } from "./test_utils.js";
+import { NodeCMapReaderFactory } from "../../src/display/node_utils.js";
 import { StringStream } from "../../src/core/stream.js";
 
 var cMapUrl = {

test/unit/custom_spec.js

@@ -13,10 +13,11 @@
  * limitations under the License.
  */
 
-import { buildGetDocumentParams, NodeCanvasFactory } from "./test_utils.js";
+import { buildGetDocumentParams } from "./test_utils.js";
 import { DOMCanvasFactory } from "../../src/display/display_utils.js";
 import { getDocument } from "../../src/display/api.js";
 import { isNodeJS } from "../../src/shared/is_node.js";
+import { NodeCanvasFactory } from "../../src/display/node_utils.js";
 
 function getTopLeftPixel(canvasContext) {
   const imgData = canvasContext.getImageData(0, 0, 1, 1);

test/unit/test_utils.js

@@ -13,7 +13,7 @@
  * limitations under the License.
  */
 
-import { assert, CMapCompressionType } from "../../src/shared/util.js";
+import { assert } from "../../src/shared/util.js";
 import { isNodeJS } from "../../src/shared/is_node.js";
 import { isRef } from "../../src/core/primitives.js";
 import { Page } from "../../src/core/document.js";
@@ -62,77 +62,6 @@ function buildGetDocumentParams(filename, options) {
   return params;
 }
 
-class NodeCanvasFactory {
-  create(width, height) {
-    assert(width > 0 && height > 0, "Invalid canvas size");
-
-    const Canvas = require("canvas");
-    const canvas = Canvas.createCanvas(width, height);
-    return {
-      canvas,
-      context: canvas.getContext("2d"),
-    };
-  }
-
-  reset(canvasAndContext, width, height) {
-    assert(canvasAndContext.canvas, "Canvas is not specified");
-    assert(width > 0 && height > 0, "Invalid canvas size");
-
-    canvasAndContext.canvas.width = width;
-    canvasAndContext.canvas.height = height;
-  }
-
-  destroy(canvasAndContext) {
-    assert(canvasAndContext.canvas, "Canvas is not specified");
-
-    // Zeroing the width and height cause Firefox to release graphics
-    // resources immediately, which can greatly reduce memory consumption.
-    canvasAndContext.canvas.width = 0;
-    canvasAndContext.canvas.height = 0;
-    canvasAndContext.canvas = null;
-    canvasAndContext.context = null;
-  }
-}
-
-class NodeCMapReaderFactory {
-  constructor({ baseUrl = null, isCompressed = false }) {
-    this.baseUrl = baseUrl;
-    this.isCompressed = isCompressed;
-  }
-
-  async fetch({ name }) {
-    if (!this.baseUrl) {
-      throw new Error(
-        'The CMap "baseUrl" parameter must be specified, ensure that ' +
-          'the "cMapUrl" and "cMapPacked" API parameters are provided.'
-      );
-    }
-    if (!name) {
-      throw new Error("CMap name must be specified.");
-    }
-    const url = this.baseUrl + name + (this.isCompressed ? ".bcmap" : "");
-    const compressionType = this.isCompressed
-      ? CMapCompressionType.BINARY
-      : CMapCompressionType.NONE;
-
-    return new Promise((resolve, reject) => {
-      const fs = require("fs");
-      fs.readFile(url, (error, data) => {
-        if (error || !data) {
-          reject(new Error(error));
-          return;
-        }
-        resolve({ cMapData: new Uint8Array(data), compressionType });
-      });
-    }).catch(reason => {
-      throw new Error(
-        `Unable to load ${this.isCompressed ? "binary " : ""}` +
-          `CMap at: ${url}`
-      );
-    });
-  }
-}
-
 class XRefMock {
   constructor(array) {
     this._map = Object.create(null);
@@ -186,8 +115,6 @@ function isEmptyObj(obj) {
 export {
   DOMFileReaderFactory,
   NodeFileReaderFactory,
-  NodeCanvasFactory,
-  NodeCMapReaderFactory,
   XRefMock,
   buildGetDocumentParams,
   TEST_PDFS_PATH,