pdf.js/src/display/node_utils.js

/* 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.
 */

import {
  BaseCanvasFactory,
  BaseCMapReaderFactory,
  BaseFilterFactory,
  BaseStandardFontDataFactory,
} from "./base_factory.js";
import { isNodeJS, warn } from "../shared/util.js";

if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
  throw new Error(
    'Module "./node_utils.js" shall not be used with MOZCENTRAL builds.'
  );
}

if (isNodeJS) {
  // eslint-disable-next-line no-var
  var packageCapability = Promise.withResolvers();
  // eslint-disable-next-line no-var
  var packageMap = null;

  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");

    // 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 {}
    }

    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
        ) {
          try {
            applyPath2DToCanvasRenderingContext(CanvasRenderingContext2D);
          } catch (ex) {
            warn(`applyPath2DToCanvasRenderingContext: "${ex}".`);
          }
          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));
};

class NodeFilterFactory extends BaseFilterFactory {}

class NodeCanvasFactory extends BaseCanvasFactory {
  /**
   * @ignore
   */
  _createCanvas(width, height) {
    const canvas = NodePackages.get("canvas");
    return canvas.createCanvas(width, height);
  }
}

class NodeCMapReaderFactory extends BaseCMapReaderFactory {
  /**
   * @ignore
   */
  _fetchData(url, compressionType) {
    return fetchData(url).then(data => ({ cMapData: data, compressionType }));
  }
}

class NodeStandardFontDataFactory extends BaseStandardFontDataFactory {
  /**
   * @ignore
   */
  _fetchData(url) {
    return fetchData(url);
  }
}

export {
  NodeCanvasFactory,
  NodeCMapReaderFactory,
  NodeFilterFactory,
  NodePackages,
  NodeStandardFontDataFactory,
};