gulpfile.mjs

/* Copyright 2016 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 * as babel from "@babel/core";
import {
  babelPluginAddHeaderComment,
  babelPluginPDFJSPreprocessor,
  babelPluginStripSrcPath,
  preprocessPDFJSCode,
} from "./external/builder/babel-plugin-pdfjs-preprocessor.mjs";
import { brotliCompressSync, constants } from "zlib";
import { colorize, COLORS_ENABLED } from "./external/color_utils.mjs";
import {
  COVERAGE_FORMAT_TO_REPORTER,
  parseCoverageFormats,
} from "./external/ccov/coverage_format.mjs";
import { exec, execSync, spawn, spawnSync } from "child_process";
import { Marked, TextRenderer } from "marked";
import autoprefixer from "autoprefixer";
import { buildPrefsSchema } from "./external/chromium/prefs.mjs";
import crypto from "crypto";
import fs from "fs";
import gulp from "gulp";
import hljs from "highlight.js";
import istanbulCoverage from "istanbul-lib-coverage";
import istanbulReportGenerator from "istanbul-reports";
import layout from "./docs/templates/layout.js";
import libReport from "istanbul-lib-report";
import ordered from "ordered-read-streams";
import path from "path";
import postcss from "gulp-postcss";
import postcssDiscardComments from "postcss-discard-comments";
import { preprocess } from "./external/builder/builder.mjs";
import rename from "gulp-rename";
import { pipeline as runPipeline } from "stream/promises";
import stream from "stream";
import TerserPlugin from "terser-webpack-plugin";
import Vinyl from "vinyl";
import webpack from "webpack";
import zip from "gulp-zip";

const __dirname = import.meta.dirname;

const BUILD_DIR = "build/";
const L10N_DIR = "l10n/";
const TEST_DIR = "test/";

const GENERIC_DIR = BUILD_DIR + "generic/";
const GENERIC_LEGACY_DIR = BUILD_DIR + "generic-legacy/";
const COMPONENTS_DIR = BUILD_DIR + "components/";
const COMPONENTS_LEGACY_DIR = BUILD_DIR + "components-legacy/";
const DEFAULT_PREFERENCES_DIR = BUILD_DIR + "default_preferences/";
const MINIFIED_DIR = BUILD_DIR + "minified/";
const MINIFIED_LEGACY_DIR = BUILD_DIR + "minified-legacy/";
const INTERNAL_VIEWER_DIR = BUILD_DIR + "internal-viewer/";
const JSDOC_BUILD_DIR = BUILD_DIR + "jsdoc/";
const GH_PAGES_DIR = BUILD_DIR + "gh-pages/";
const DIST_DIR = BUILD_DIR + "dist/";
const TYPES_DIR = BUILD_DIR + "types/";
const TMP_DIR = BUILD_DIR + "tmp/";
const PREFSTEST_DIR = BUILD_DIR + "prefstest/";
const TYPESTEST_DIR = BUILD_DIR + "typestest/";
const MOZCENTRAL_DIR = BUILD_DIR + "mozcentral/";
const MOZCENTRAL_EXTENSION_DIR = MOZCENTRAL_DIR + "browser/extensions/pdfjs/";
const MOZCENTRAL_CONTENT_DIR = MOZCENTRAL_EXTENSION_DIR + "content/";
const MOZCENTRAL_L10N_DIR = MOZCENTRAL_DIR + "browser/locales/en-US/pdfviewer/";
const CHROMIUM_DIR = BUILD_DIR + "chromium/";
const COMMON_WEB_FILES = [
  "web/images/*.{png,svg,gif}",
  "web/debugger.{css,mjs}",
];

const CONFIG_FILE = "pdfjs.config";
const config = JSON.parse(fs.readFileSync(CONFIG_FILE).toString());

const ENV_TARGETS = [
  "last 2 versions",
  "Chrome >= 125",
  "Firefox ESR",
  "Safari >= 18",
  "Node >= 22",
  "> 1%",
  "not IE > 0",
  "not dead",
];

// Default Autoprefixer config used for generic, components, minified-pre
const AUTOPREFIXER_CONFIG = {
  overrideBrowserslist: ENV_TARGETS,
};
// Default Babel targets used for generic, components, minified-pre
const BABEL_TARGETS = ENV_TARGETS.join(", ");

const BABEL_COREJS_OPTS = Object.freeze({
  method: "usage-global",
  version: "3.51.0",
  exclude: ["web.structured-clone"],
  shippedProposals: true,
});

const DEFINES = Object.freeze({
  SKIP_BABEL: true,
  WORKER_THREAD: false,
  TESTING: undefined,
  COVERAGE: undefined,
  INTERNAL_EVT: crypto.randomUUID(),
  // The main build targets:
  GENERIC: false,
  MOZCENTRAL: false,
  GECKOVIEW: false,
  CHROME: false,
  MINIFIED: false,
  COMPONENTS: false,
  LIB: false,
  INTERNAL_VIEWER: false,
});

function transform(charEncoding, transformFunction) {
  return new stream.Transform({
    objectMode: true,
    transform(vinylFile, enc, done) {
      const transformedFile = vinylFile.clone();
      transformedFile.contents = Buffer.from(
        transformFunction(transformedFile.contents),
        charEncoding
      );
      done(null, transformedFile);
    },
  });
}

function safeSpawnSync(command, parameters, options = {}) {
  // Execute all commands in a shell.
  options.shell = true;
  // `options.shell = true` requires parameters to be quoted.
  parameters = parameters.map(param =>
    !/[\s`~!#$*(){[|\\;'"<>?]/.test(param)
      ? param
      : '"' + param.replaceAll(/([$\\"`])/g, "\\$1") + '"'
  );

  const result = spawnSync(command, parameters, options);
  if (result.status !== 0) {
    console.log(
      'Error: command "' +
        command +
        '" with parameters "' +
        parameters +
        '" exited with code ' +
        result.status
    );
    process.exit(result.status);
  }
  return result;
}

function startNode(args, options) {
  // Node.js decreased the maximum header size from 80 KB to 8 KB in newer
  // releases, which is not sufficient for some of our reference test files
  // (such as `issue6360.pdf`), so we need to restore this value. Note that
  // this argument needs to be before all other arguments as it needs to be
  // passed to the Node.js process itself and not to the script that it runs.
  args.unshift("--max-http-header-size=80000");
  return spawn("node", args, options);
}

function createStringSource(filename, content) {
  const source = stream.Readable({ objectMode: true });
  source._read = function () {
    this.push(
      new Vinyl({
        path: filename,
        contents: Buffer.from(content),
      })
    );
    this.push(null);
  };
  return source;
}

function createWebpackAlias(defines) {
  const basicAlias = {
    pdfjs: "src",
    "pdfjs-web": "web",
    "pdfjs-lib": "web/pdfjs",
    "fluent-bundle": "node_modules/@fluent/bundle/esm/index.js",
    "fluent-dom": "node_modules/@fluent/dom/esm/index.js",
  };
  const libraryAlias = {
    "display-binary_data_factory": "src/display/stubs.js",
    "display-network_stream": "src/display/stubs.js",
    "display-node_utils": "src/display/stubs.js",
  };
  const viewerAlias = {
    "web-alt_text_manager": "web/alt_text_manager.js",
    "web-annotation_editor_params": "web/annotation_editor_params.js",
    "web-download_manager": "",
    "web-external_services": "",
    "web-new_alt_text_manager": "web/new_alt_text_manager.js",
    "web-null_l10n": "",
    "web-pdf_attachment_viewer": "web/pdf_attachment_viewer.js",
    "web-pdf_cursor_tools": "web/pdf_cursor_tools.js",
    "web-pdf_document_properties": "web/pdf_document_properties.js",
    "web-pdf_find_bar": "web/pdf_find_bar.js",
    "web-pdf_layer_viewer": "web/pdf_layer_viewer.js",
    "web-pdf_outline_viewer": "web/pdf_outline_viewer.js",
    "web-pdf_presentation_mode": "web/pdf_presentation_mode.js",
    "web-pdf_thumbnail_viewer": "web/pdf_thumbnail_viewer.js",
    "web-preferences": "",
    "web-print_service": "",
    "web-secondary_toolbar": "web/secondary_toolbar.js",
    "web-signature_manager": "web/signature_manager.js",
    "web-digital_signature_properties_manager":
      "web/digital_signature_properties_manager.js",
    "web-toolbar": "web/toolbar.js",
    "web-views_manager": "web/views_manager.js",
  };

  if (defines.CHROME) {
    libraryAlias["display-binary_data_factory"] =
      "src/display/binary_data_factory.js";
    libraryAlias["display-network_stream"] = "src/display/network_stream.js";

    viewerAlias["web-download_manager"] = "web/chromecom.js";
    viewerAlias["web-external_services"] = "web/chromecom.js";
    viewerAlias["web-null_l10n"] = "web/l10n.js";
    viewerAlias["web-preferences"] = "web/chromecom.js";
    viewerAlias["web-print_service"] = "web/pdf_print_service.js";
  } else if (defines.GENERIC) {
    // Aliases defined here must also be replicated in the paths section of
    // the tsconfig.json file for the type generation to work.
    // In the tsconfig.json files, the .js extension must be omitted.
    libraryAlias["display-binary_data_factory"] =
      "src/display/binary_data_factory.js";
    libraryAlias["display-network_stream"] = "src/display/network_stream.js";
    libraryAlias["display-node_utils"] = "src/display/node_utils.js";

    viewerAlias["web-download_manager"] = "web/download_manager.js";
    viewerAlias["web-external_services"] = "web/genericcom.js";
    viewerAlias["web-null_l10n"] = "web/genericl10n.js";
    viewerAlias["web-preferences"] = "web/genericcom.js";
    viewerAlias["web-print_service"] = "web/pdf_print_service.js";
  } else if (defines.MOZCENTRAL) {
    if (defines.GECKOVIEW) {
      const gvAlias = {
        "web-signature_manager": "web/signature_manager-geckoview.js",
        "web-toolbar": "web/toolbar-geckoview.js",
      };
      for (const key in viewerAlias) {
        viewerAlias[key] = gvAlias[key] || "web/stubs-geckoview.js";
      }
    }
    viewerAlias["web-download_manager"] = "web/firefoxcom.js";
    viewerAlias["web-external_services"] = "web/firefoxcom.js";
    viewerAlias["web-null_l10n"] = "web/l10n.js";
    viewerAlias["web-preferences"] = "web/firefoxcom.js";
    viewerAlias["web-print_service"] = "web/firefox_print_service.js";
  }

  const alias = { ...basicAlias, ...libraryAlias, ...viewerAlias };
  for (const key in alias) {
    alias[key] = path.join(__dirname, alias[key]);
  }
  return alias;
}

/**
 * Webpack's file and missing dependencies, keyed by output filename.
 * @type {Map<string, Set<string>>}
 */
const webpackFileDeps = new Map();

/** Return a Webpack plugin that records dependencies for `filename`. */
function recordFileDeps(filename) {
  return {
    /** @param {import('webpack').Compiler} compiler */
    apply(compiler) {
      compiler.hooks.done.tap("RecordFileDependencies", ({ compilation }) => {
        const dependencies = new Set([
          ...compilation.fileDependencies,
          ...compilation.missingDependencies,
        ]);

        // Preserve known dependencies after a failed compilation.
        if (compilation.errors.length > 0) {
          for (const dependency of webpackFileDeps.get(filename) ?? []) {
            dependencies.add(dependency);
          }
        }
        webpackFileDeps.set(filename, dependencies);
      });
    },
  };
}

function createWebpackConfig(
  defines,
  output,
  {
    disableVersionInfo = false,
    disableSourceMaps = false,
    disableLicenseHeader = false,
  } = {}
) {
  const versionInfo = !disableVersionInfo
    ? getVersionJSON()
    : { version: 0, commit: 0 };
  const bundleDefines = {
    ...defines,
    BUNDLE_VERSION: versionInfo.version,
    BUNDLE_BUILD: versionInfo.commit,
    TESTING: defines.TESTING ?? process.env.TESTING === "true",
    COVERAGE:
      defines.COVERAGE ??
      (process.argv.includes("--coverage") ||
        process.argv.includes("--coverage-per-test")),
    DEFAULT_FTL: defines.GENERIC ? getDefaultFtl() : "",
  };
  const licenseHeaderLibre = fs
    .readFileSync("./src/license_header_libre.js")
    .toString();
  const versionInfoHeader = [
    "/**",
    ` * pdfjsVersion = ${versionInfo.version}`,
    ` * pdfjsBuild = ${versionInfo.commit}`,
    " */",
  ].join("\n");
  const enableSourceMaps =
    !bundleDefines.MOZCENTRAL &&
    !bundleDefines.CHROME &&
    !bundleDefines.LIB &&
    !bundleDefines.MINIFIED &&
    (!bundleDefines.TESTING || bundleDefines.COVERAGE) &&
    !disableSourceMaps;
  const isModule = output.library?.type === "module";
  const isMinified = bundleDefines.MINIFIED;
  const skipBabel = bundleDefines.SKIP_BABEL;

  const babelExcludeRegExp = [
    // `core-js`, see https://github.com/zloirock/core-js/issues/514,
    // should be excluded from processing.
    /node_modules[\\/]core-js/,
  ];

  const babelPresets = skipBabel ? undefined : ["@babel/preset-env"];
  const babelPlugins = [
    [
      babelPluginPDFJSPreprocessor,
      {
        rootPath: __dirname,
        defines: bundleDefines,
      },
    ],
  ];
  if (!skipBabel) {
    babelPlugins.push(["babel-plugin-polyfill-corejs3", BABEL_COREJS_OPTS]);
  }
  if (bundleDefines.COVERAGE) {
    babelPlugins.push("babel-plugin-istanbul");
  }

  const plugins = [];
  if (!disableLicenseHeader) {
    plugins.push(
      new webpack.BannerPlugin({
        banner: licenseHeaderLibre + "\n" + versionInfoHeader,
        raw: true,
      })
    );
  }
  plugins.push(recordFileDeps(output.filename), {
    /** @param {import('webpack').Compiler} compiler */
    apply(compiler) {
      const errors = [];

      compiler.hooks.afterCompile.tap("VerifyImportMeta", compilation => {
        for (const asset of compilation.getAssets()) {
          if (asset.name.endsWith(".mjs")) {
            const source = asset.source.source();
            if (
              typeof source === "string" &&
              /new URL\([^,)]*,\s*import\.meta\.url/.test(source)
            ) {
              errors.push(
                `Output module ${asset.name} uses new URL(..., import.meta.url)`
              );
            }
          }
        }
      });
      compiler.hooks.afterEmit.tap("VerifyImportMeta", compilation => {
        compilation.errors.push(...errors);
      });
    },
  });

  const alias = createWebpackAlias(bundleDefines);
  const experiments = isModule ? { outputModule: true } : undefined;

  // Required to expose e.g., the `window` object.
  output.globalObject = "globalThis";

  return {
    mode: "production",
    optimization: {
      mangleExports: false,
      minimize: isMinified,
      minimizer: !isMinified
        ? undefined
        : [
            new TerserPlugin({
              extractComments: false,
              parallel: false,
              terserOptions: {
                compress: {
                  // V8 chokes on very long sequences, work around that.
                  sequences: false,
                },
                format: {
                  comments: /@lic|webpackIgnore|@vite-ignore|pdfjsVersion/i,
                },
                keep_classnames: true,
                keep_fnames: true,
                module: isModule,
              },
            }),
          ],
    },
    experiments,
    output,
    performance: {
      hints: false, // Disable messages about larger file sizes.
    },
    plugins,
    resolve: {
      alias,
    },
    devtool: enableSourceMaps ? "source-map" : undefined,
    module: {
      parser: {
        javascript: {
          importMeta: false,
          url: false,
        },
      },
      rules: [
        {
          test: /\.[mc]?js$/,
          loader: "babel-loader",
          exclude: babelExcludeRegExp,
          options: {
            presets: babelPresets,
            plugins: babelPlugins,
            targets: BABEL_TARGETS,
          },
        },
      ],
    },
    // Avoid shadowing actual Node.js variables with polyfills, by disabling
    // polyfills/mocks - https://webpack.js.org/configuration/node/
    node: false,
  };
}

class WebpackCompilationError extends Error {
  // Omit the stack trace in gulp's error output.
  showStack = false;
}

/** Bundle `entry` into an in-memory Vinyl stream. */
function createWebpackStream(entry, webpackConfig) {
  const outputPath = __dirname;
  const files = [];
  const readable = new stream.Readable({ objectMode: true, read() {} });

  const compiler = webpack({
    ...webpackConfig,
    entry: path.resolve(entry),
    output: {
      ...webpackConfig.output,
      path: outputPath,
      compareBeforeEmit: false,
    },
  });
  compiler.outputFileSystem = {
    mkdir(_dirPath, callback) {
      callback(null);
    },
    writeFile(filePath, contents, callback) {
      files.push(new Vinyl({ base: outputPath, path: filePath, contents }));
      callback(null);
    },
  };

  compiler.run((runError, stats) => {
    compiler.close(closeError => {
      if (runError || closeError) {
        readable.destroy(runError || closeError);
        return;
      }
      console.log(
        stats.toString({
          colors: COLORS_ENABLED,
          chunks: false,
          hash: false,
          modules: false,
          timings: false,
        })
      );
      if (stats.hasErrors()) {
        readable.destroy(
          new WebpackCompilationError(`Webpack failed to bundle "${entry}".`)
        );
        return;
      }
      for (const file of files) {
        readable.push(file);
      }
      readable.push(null);
    });
  });
  return readable;
}

/** Write a Vinyl stream to `dest` and wait for completion. */
function writeToDirectory(readable, dest) {
  return runPipeline(
    readable,
    gulp.dest(dest),
    // Drain `gulp.dest`'s readable side to prevent backpressure.
    new stream.Writable({
      objectMode: true,
      write(_file, _encoding, callback) {
        callback();
      },
    })
  );
}

function getErrorMessages(error) {
  if (error instanceof AggregateError) {
    return error.errors.flatMap(getErrorMessages);
  }
  if (error instanceof WebpackCompilationError) {
    // createWebpackStream already logged the diagnostics.
    return [];
  }
  return [
    error instanceof Error ? error.stack || error.message : String(error),
  ];
}

function reportBuildFailure(error) {
  console.error(colorize("red", `\n### ${error?.message || "Build failed"}`));
  for (const message of getErrorMessages(error)) {
    console.error(colorize("red", message));
  }
}

/** Return a repository-relative path with POSIX separators. */
function repoPath(filePath) {
  return path.relative(__dirname, filePath).split(path.sep).join("/");
}

function getVersionJSON() {
  return JSON.parse(fs.readFileSync(BUILD_DIR + "version.json").toString());
}

function createMainBundle(defines) {
  const mainFileConfig = createWebpackConfig(defines, {
    filename: defines.MINIFIED ? "pdf.min.mjs" : "pdf.mjs",
    library: {
      type: "module",
    },
  });
  return createWebpackStream("./src/pdf.js", mainFileConfig);
}

function createScriptingBundle(defines, extraOptions = undefined) {
  const scriptingFileConfig = createWebpackConfig(
    defines,
    {
      filename: "pdf.scripting.mjs",
      iife: true,
    },
    extraOptions
  );
  return createWebpackStream("./src/pdf.scripting.js", scriptingFileConfig);
}

function createSandboxExternal(defines) {
  const licenseHeader = fs.readFileSync("./src/license_header.js").toString();

  const ctx = {
    defines,
  };
  return gulp
    .src("./src/pdf.sandbox.external.js", { encoding: false })
    .pipe(rename("pdf.sandbox.external.sys.mjs"))
    .pipe(
      transform("utf8", content => {
        content = preprocessPDFJSCode(ctx, content);
        return `${licenseHeader}\n${content}`;
      })
    );
}

function createTemporaryScriptingBundle(defines, extraOptions = undefined) {
  return createScriptingBundle(defines, {
    disableVersionInfo: !!extraOptions?.disableVersionInfo,
    disableSourceMaps: true,
    disableLicenseHeader: true,
  }).pipe(gulp.dest(TMP_DIR));
}

function createSandboxBundle(defines, extraOptions = undefined) {
  const scriptingPath = TMP_DIR + "pdf.scripting.mjs";
  // Insert the source as a string to be `eval`-ed in the sandbox.
  const sandboxDefines = {
    ...defines,
    PDF_SCRIPTING_JS_SOURCE: fs.readFileSync(scriptingPath).toString(),
  };
  fs.unlinkSync(scriptingPath);

  const sandboxFileConfig = createWebpackConfig(
    sandboxDefines,
    {
      filename: sandboxDefines.MINIFIED
        ? "pdf.sandbox.min.mjs"
        : "pdf.sandbox.mjs",
      library: {
        type: "module",
      },
    },
    extraOptions
  );

  return createWebpackStream("./src/pdf.sandbox.js", sandboxFileConfig);
}

function createWorkerBundle(defines) {
  const workerDefines = {
    ...defines,
    WORKER_THREAD: true,
  };
  const workerFileConfig = createWebpackConfig(workerDefines, {
    filename: workerDefines.MINIFIED ? "pdf.worker.min.mjs" : "pdf.worker.mjs",
    library: {
      type: "module",
    },
  });
  return createWebpackStream("./src/pdf.worker.js", workerFileConfig);
}

function createRendererWorkerBundle(defines) {
  const rendererWorkerDefines = {
    ...defines,
    WORKER_THREAD: true,
  };
  const rendererWorkerFileConfig = createWebpackConfig(rendererWorkerDefines, {
    filename: rendererWorkerDefines.MINIFIED
      ? "pdf.renderer.min.mjs"
      : "pdf.renderer.mjs",
    library: {
      type: "module",
    },
  });
  return createWebpackStream("./src/pdf.renderer.js", rendererWorkerFileConfig);
}

function createWebBundle(defines, options) {
  const viewerFileConfig = createWebpackConfig(defines, {
    filename: "viewer.mjs",
    library: {
      type: "module",
    },
  });
  return createWebpackStream("./web/viewer.js", viewerFileConfig);
}

function createGVWebBundle(defines, options) {
  const viewerFileConfig = createWebpackConfig(defines, {
    filename: "viewer-geckoview.mjs",
    library: {
      type: "module",
    },
  });
  return createWebpackStream("./web/viewer-geckoview.js", viewerFileConfig);
}

function createComponentsBundle(defines) {
  const componentsFileConfig = createWebpackConfig(defines, {
    filename: "pdf_viewer.mjs",
    library: {
      type: "module",
    },
  });
  return createWebpackStream(
    "./web/pdf_viewer.component.js",
    componentsFileConfig
  );
}

function createCMapBundle() {
  return gulp.src(["external/bcmaps/*.bcmap.br", "external/bcmaps/LICENSE"], {
    base: "external/bcmaps",
    encoding: false,
  });
}

function createICCBundle() {
  return gulp.src(["external/iccs/*.icc", "external/iccs/LICENSE"], {
    base: "external/iccs",
    encoding: false,
  });
}

function createStandardFontBundle() {
  return gulp.src(
    [
      "external/hellbox/*.hbgd",
      "external/hellbox/unicode.bin",
      "external/hellbox/LICENSE_*",
      "!external/hellbox/LICENSE_HELLBOX",
    ],
    {
      base: "external/hellbox",
      encoding: false,
    }
  );
}

function brotliCompressFallbacks() {
  return new stream.Transform({
    objectMode: true,
    transform(file, enc, done) {
      if (file.basename.endsWith("_nowasm_fallback.js")) {
        file.contents = brotliCompressSync(file.contents, {
          params: {
            [constants.BROTLI_PARAM_MODE]: constants.BROTLI_MODE_TEXT,
            [constants.BROTLI_PARAM_QUALITY]: constants.BROTLI_MAX_QUALITY,
            [constants.BROTLI_PARAM_LGWIN]: constants.BROTLI_MAX_WINDOW_BITS,
            [constants.BROTLI_PARAM_SIZE_HINT]: file.contents.length,
          },
        });
        file.extname += ".br";
      }
      done(null, file);
    },
  });
}

function createWasmBundle({ includeQuickJS = true } = {}) {
  const modules = [
    ["openjpeg", ["*.wasm", "openjpeg_nowasm_fallback.js", "LICENSE_*"]],
    ["qcms", ["*.wasm", "LICENSE_*"]],
    ["hellbox", ["*.wasm", "hellbox_nowasm_fallback.js", "LICENSE_HELLBOX"]],
    ["jbig2", ["*.wasm", "jbig2_nowasm_fallback.js", "LICENSE_*"]],
  ];
  if (includeQuickJS) {
    modules.push([
      "quickjs",
      ["quickjs-eval.js", "quickjs-eval.wasm", "LICENSE_*"],
    ]);
  }
  return ordered(
    modules.map(([name, files]) => {
      const base = `external/${name}`;
      return gulp.src(
        files.map(file => `${base}/${file}`),
        { base, encoding: false }
      );
    })
  );
}

function checkFile(filePath) {
  try {
    const stat = fs.lstatSync(filePath);
    return stat.isFile();
  } catch {
    return false;
  }
}

function checkDir(dirPath) {
  try {
    const stat = fs.lstatSync(dirPath);
    return stat.isDirectory();
  } catch {
    return false;
  }
}

function getTempFile(prefix, suffix) {
  fs.mkdirSync(BUILD_DIR + "tmp/", { recursive: true });
  const bytes = crypto.randomBytes(6).toString("hex");
  const filePath = BUILD_DIR + "tmp/" + prefix + bytes + suffix;
  fs.writeFileSync(filePath, "");
  return filePath;
}

function getArgValue(name) {
  for (let i = 0; i < process.argv.length; i++) {
    if (process.argv[i] === name && i + 1 < process.argv.length) {
      return process.argv[i + 1];
    }
    if (process.argv[i].startsWith(name + "=")) {
      return process.argv[i].slice(name.length + 1);
    }
  }
  return null;
}

function runTests(testsName, { bot = false } = {}) {
  return new Promise((resolve, reject) => {
    console.log("\n### Running " + testsName + " tests");

    const PDF_TEST = process.env.PDF_TEST || "test_manifest.json";
    let forceNoChrome = false;
    const args = ["test.mjs"];
    switch (testsName) {
      case "browser":
        if (!bot) {
          args.push("--reftest");
        } else {
          // The browser-tests are too slow in Google Chrome on the bots,
          // causing a timeout, hence disabling them for now.
          forceNoChrome = true;
        }
        args.push("--manifestFile=" + PDF_TEST);
        collectArgs(
          [
            { names: ["-t", "--testfilter"], hasValue: true },
            { names: ["-j", "--jobs"], hasValue: true },
            { names: ["--shard"], hasValue: true },
            { names: ["--summaryFile"], hasValue: true },
          ],
          args
        );
        break;
      case "unit":
        args.push("--unitTest");
        break;
      case "font":
        args.push("--fontTest");
        break;
      case "integration":
        args.push("--integration");
        break;
      default:
        reject(new Error(`Unknown tests name '${testsName}'`));
        return;
    }
    if (bot) {
      args.push("--strictVerify");
    }
    if (process.argv.includes("--noBrowserDownload")) {
      args.push("--noBrowserDownload");
    }
    if (process.argv.includes("--noChrome") || forceNoChrome) {
      args.push("--noChrome");
    }
    if (process.argv.includes("--noFirefox")) {
      args.push("--noFirefox");
    }
    if (process.argv.includes("--headless")) {
      args.push("--headless");
    }
    if (
      process.argv.includes("--coverage") ||
      process.argv.includes("--coverage-per-test")
    ) {
      args.push("--coverage");
    }
    if (process.argv.includes("--coverage-output")) {
      args.push(
        "--coverageOutput",
        process.argv[process.argv.indexOf("--coverage-output") + 1]
      );
    }
    const coverageFormatsArg = getArgValue("--coverage-formats");
    if (coverageFormatsArg) {
      args.push("--coverageFormats", coverageFormatsArg);
    }
    if (process.argv.includes("--coverage-per-test")) {
      args.push("--coveragePerTest");
    }

    if (testsName === "browser") {
      let shouldRun;
      try {
        shouldRun = applyCodeTestFilter(args);
      } catch (error) {
        reject(error);
        return;
      }
      if (!shouldRun) {
        resolve();
        return;
      }
    }

    const testProcess = startNode(args, { cwd: TEST_DIR, stdio: "inherit" });
    testProcess.on("close", function (code) {
      if (code !== 0) {
        reject(new Error(`Running ${testsName} tests failed.`));
        return;
      }
      resolve();
    });
  });
}

function collectArgs(options, args) {
  if (!Array.isArray(options)) {
    options = [options];
  }
  for (let i = 0, ii = process.argv.length; i < ii; i++) {
    const arg = process.argv[i];

    // Exact name match (flag only, or flag with space-separated value).
    const exactOption = options.find(opt => opt.names.includes(arg));
    if (exactOption) {
      if (!exactOption.hasValue) {
        args.push(arg);
        continue;
      }
      const next = process.argv[i + 1];
      if (next && !next.startsWith("-")) {
        args.push(arg, next);
        i += 1;
      }
      continue;
    }

    // Also handle --flag=value and -fvalue (concatenated short) forms.
    for (const option of options) {
      if (!option.hasValue) {
        continue;
      }
      let matched = false;
      for (const name of option.names) {
        if (name.startsWith("--") && arg.startsWith(name + "=")) {
          // --flag=value
          args.push(name, arg.slice(name.length + 1));
          matched = true;
          break;
        }
        if (
          !name.startsWith("--") &&
          arg.startsWith(name) &&
          arg.length > name.length
        ) {
          // -fvalue (short option with concatenated value)
          args.push(name, arg.slice(name.length));
          matched = true;
          break;
        }
      }
      if (matched) {
        break;
      }
    }
  }
}

// Builds the coverage_search command line. By default the published index is
// downloaded; an explicit --index=<path> selects a local index instead, used
// read-only so it's never overwritten by the published copy.
function getCoverageSearchArgs(codeArg) {
  const searchArgs = [
    path.join(__dirname, "external/ccov/coverage_search.mjs"),
    `--code=${codeArg}`,
  ];
  const indexArg = getArgValue("--index");
  if (indexArg === "") {
    // An explicit but empty value (e.g. an unset shell variable expanding to
    // `--index=`) almost certainly isn't intended; fail loudly rather than
    // silently falling back to the downloaded index.
    throw new Error("--index was given without a value");
  }
  if (indexArg) {
    searchArgs.push(`--index=${indexArg}`, "--no-download");
  } else if (process.argv.includes("--no-download")) {
    searchArgs.push("--no-download");
  }
  return searchArgs;
}

// Returns the set of test IDs defined in the local ref-test manifest, or null
// when it can't be read. Used to drop coverage-derived IDs that don't exist on
// this branch (e.g. a test renamed since the published index was built), which
// would otherwise make test.mjs reject the entire run.
function readManifestTestIds() {
  try {
    const manifestFile = process.env.PDF_TEST || "test_manifest.json";
    const manifest = JSON.parse(
      fs.readFileSync(path.join(__dirname, TEST_DIR, manifestFile), "utf8")
    );
    return new Set(manifest.map(entry => entry.id));
  } catch {
    return null;
  }
}

// For a --code=<file>::<line|function> argument, runs coverage_search to find
// the ref tests that exercise that location and returns their IDs (an empty
// array when none match locally). Returns null when --code wasn't given; throws
// when the search itself fails.
function resolveCodeTestIds() {
  const codeArg = getArgValue("--code");
  if (!codeArg) {
    return null;
  }
  // Inherit stderr so the index download progress is visible; stdout is
  // captured because it carries the matching test IDs.
  const result = spawnSync("node", getCoverageSearchArgs(codeArg), {
    encoding: "utf8",
    stdio: ["ignore", "pipe", "inherit"],
  });
  if (result.status !== 0) {
    // status is null when the child couldn't be spawned or was killed by a
    // signal; surface the real cause instead of a generic message.
    throw new Error(
      result.error
        ? `coverage_search failed: ${result.error.message}`
        : `coverage_search failed (exit code ${result.status})`
    );
  }
  let testIds = result.stdout.trim().split("\n").filter(Boolean);

  // The published index is built from master, so some covering tests may not
  // exist on this branch. Drop them (with a note) rather than letting test.mjs
  // reject the whole run — and silently exit 0 — on the first unknown ID.
  const knownIds = readManifestTestIds();
  if (knownIds) {
    const missing = testIds.filter(id => !knownIds.has(id));
    if (missing.length) {
      console.log(
        `\n### Ignoring ${missing.length} covered test(s) not in the manifest:\n` +
          missing.map(id => `  ${id}`).join("\n")
      );
      testIds = testIds.filter(id => knownIds.has(id));
    }
  }

  if (testIds.length === 0) {
    console.log(`\n### No tests found covering "${codeArg}"`);
  } else {
    console.log(
      `\n### Found ${testIds.length} test(s) covering "${codeArg}":\n` +
        testIds.map(id => `  ${id}`).join("\n")
    );
  }
  return testIds;
}

function appendTestFilters(args, testIds) {
  const existingIds = new Set();

  // collectArgs always normalizes filters to the space-separated
  // `-t <id>` / `--testfilter <id>` form, so that's the only shape to read.
  for (let i = 0; i < args.length; i++) {
    if (args[i] === "-t" || args[i] === "--testfilter") {
      if (i + 1 < args.length) {
        existingIds.add(args[++i]);
      }
    }
  }
  for (const id of testIds) {
    if (!existingIds.has(id)) {
      // Pass the id as a separate argument: node's parseArgs parses the short
      // form `-t=<id>` as the literal value "=<id>", which matches no test and
      // aborts the run with "Unrecognized test IDs".
      args.push("-t", id);
      existingIds.add(id);
    }
  }
}

// Applies the --code coverage filter to `args`. Returns false when the run
// should be skipped (--code was given but resolved to no runnable tests), and
// true otherwise (no --code, or matching tests were appended). Throws when the
// coverage search itself fails.
function applyCodeTestFilter(args) {
  const codeTestIds = resolveCodeTestIds();
  if (codeTestIds === null) {
    return true; // No --code argument; run normally.
  }
  if (codeTestIds.length === 0) {
    return false; // Nothing (runnable) covers the requested location.
  }
  appendTestFilters(args, codeTestIds);
  return true;
}

function makeRef(done, bot) {
  console.log("\n### Creating reference images");

  let forceNoChrome = false;
  const args = ["test.mjs", "--masterMode"];
  if (bot) {
    // The browser-tests are too slow in Google Chrome on the bots,
    // causing a timeout, hence disabling them for now.
    forceNoChrome = true;

    args.push("--noPrompts", "--strictVerify");
  }
  if (process.argv.includes("--noBrowserDownload")) {
    args.push("--noBrowserDownload");
  }
  if (process.argv.includes("--noChrome") || forceNoChrome) {
    args.push("--noChrome");
  }
  if (process.argv.includes("--noFirefox")) {
    args.push("--noFirefox");
  }
  if (process.argv.includes("--headless")) {
    args.push("--headless");
  }
  if (
    process.argv.includes("--coverage") ||
    process.argv.includes("--coverage-per-test")
  ) {
    args.push("--coverage");
  }
  if (process.argv.includes("--coverage-output")) {
    args.push(
      "--coverageOutput",
      process.argv[process.argv.indexOf("--coverage-output") + 1]
    );
  }
  const coverageFormatsArg = getArgValue("--coverage-formats");
  if (coverageFormatsArg) {
    args.push("--coverageFormats", coverageFormatsArg);
  }
  if (process.argv.includes("--coverage-per-test")) {
    args.push("--coveragePerTest");
  }
  collectArgs(
    [
      { names: ["-t", "--testfilter"], hasValue: true },
      { names: ["-j", "--jobs"], hasValue: true },
      { names: ["--shard"], hasValue: true },
      { names: ["--summaryFile"], hasValue: true },
    ],
    args
  );

  let shouldRun;
  try {
    shouldRun = applyCodeTestFilter(args);
  } catch (error) {
    done(error);
    return;
  }
  if (!shouldRun) {
    done();
    return;
  }

  const testProcess = startNode(args, { cwd: TEST_DIR, stdio: "inherit" });
  testProcess.on("close", function (code) {
    if (code !== 0) {
      done(new Error("Creating reference images failed."));
      return;
    }
    done();
  });
}

// Prints the IDs of tests that exercised a given source file location, using
// the per-test coverage index published to the pdf.js.refs repository. The
// index is downloaded on demand, cached locally, and only re-downloaded when
// it has changed. Run with --code=<file>::<line|function>, e.g.
// --code=canvas.js::205 (add --no-download to reuse the cached index offline).
gulp.task("coverage_search", function (done) {
  const codeArg = getArgValue("--code");
  if (!codeArg) {
    done(new Error('Missing --code argument, e.g. --code="canvas.js::205"'));
    return;
  }
  let searchArgs;
  try {
    searchArgs = getCoverageSearchArgs(codeArg);
  } catch (error) {
    done(error);
    return;
  }
  const result = spawnSync("node", searchArgs, { stdio: "inherit" });
  if (result.status !== 0) {
    done(
      new Error(
        result.error
          ? `coverage_search failed: ${result.error.message}`
          : `coverage_search failed (exit code ${result.status})`
      )
    );
    return;
  }
  done();
});

gulp.task("default", function (done) {
  console.log("Available tasks:");
  const tasks = Object.keys(gulp.registry().tasks());
  for (const taskName of tasks.sort()) {
    if (taskName.endsWith("-pre")) {
      continue;
    }
    console.log("  " + taskName);
  }
  done();
});

gulp.task("release-brotli", async function () {
  const hashIndex = process.argv.indexOf("--hash");
  if (hashIndex === -1 || hashIndex + 1 >= process.argv.length) {
    throw new Error('Missing "--hash <commit-hash>" argument.');
  }
  console.log();
  console.log("### Getting Brotli js file for release");

  const hash = process.argv[hashIndex + 1];
  const url = `https://raw.githubusercontent.com/google/brotli/${hash}/js/decode.js`;
  const outputPath = "./external/brotli/decode.js";
  const res = await fetch(url);
  if (!res.ok) {
    throw new Error(`Failed to fetch ${url}: ${res.status}`);
  }
  // Export the factory so that decoder tables can be initialized lazily.
  const source = await res.text();
  const patchedSource = source.replace(
    /\/\*\*\n \* @type \{[^}]+\}\n \*\/\nexport let BrotliDecode = makeBrotliDecode\(\);/,
    "export { makeBrotliDecode };"
  );
  if (patchedSource === source) {
    throw new Error("Unexpected `BrotliDecode` export in decode.js.");
  }
  // Forcibly invoke `enableLargeWindow` until the option is exposed upstream.
  const enableLargeWindowSource = patchedSource.replace(
    /(\sinitState\(s\);)\n(\s*if \(options\) \{)/,
    "$1\n    enableLargeWindow(s);\n$2"
  );
  if (enableLargeWindowSource === patchedSource) {
    throw new Error("Cannot patch `enableLargeWindow` into decode.js.");
  }
  fs.writeFileSync(outputPath, enableLargeWindowSource);

  console.log(`Brotli js file saved to: ${outputPath}`);
});

function createBuildNumber(done) {
  console.log("\n### Getting extension build number");

  exec(
    "git log --format=oneline " + config.baseVersion + "..",
    function (err, stdout, stderr) {
      let buildNumber = 0;
      if (!err) {
        // Build number is the number of commits since base version
        buildNumber = stdout ? stdout.match(/\n/g).length : 0;
      } else {
        console.log(
          "This is not a Git repository; using default build number."
        );
      }

      console.log("Extension build number: " + buildNumber);

      const version = config.versionPrefix + buildNumber;

      exec('git log --format="%h" -n 1', function (err2, stdout2, stderr2) {
        const buildCommit = !err2 ? stdout2.replace("\n", "") : "";

        createStringSource(
          "version.json",
          JSON.stringify(
            {
              version,
              build: buildNumber,
              commit: buildCommit,
            },
            null,
            2
          )
        )
          .pipe(gulp.dest(BUILD_DIR))
          .on("end", done);
      });
    }
  );
}

function createDefaultPreferencesBundle(defines, dir) {
  console.log(`\n### Building default preferences (${dir})`);

  const bundleDefines = {
    ...defines,
    LIB: true,
    TESTING: defines.TESTING ?? process.env.TESTING === "true",
  };

  const defaultPreferencesConfig = createWebpackConfig(
    bundleDefines,
    {
      filename: "app_options.mjs",
      library: {
        type: "module",
      },
    },
    {
      disableVersionInfo: true,
    }
  );
  return createWebpackStream("web/app_options.js", defaultPreferencesConfig);
}

function buildDefaultPreferences(defines, dir) {
  return createDefaultPreferencesBundle(defines, dir).pipe(
    gulp.dest(DEFAULT_PREFERENCES_DIR + dir)
  );
}

let defaultPreferencesId = 0;

async function getDefaultPreferences(dir) {
  console.log(`\n### Parsing default preferences (${dir})`);

  const url = new URL(
    `${DEFAULT_PREFERENCES_DIR}${dir}app_options.mjs`,
    import.meta.url
  );
  // Node caches ES modules by URL; vary it to reload this bundle in watch mode.
  url.searchParams.set("id", defaultPreferencesId++);

  // eslint-disable-next-line no-unsanitized/method
  const { AppOptions, OptionKind } = await import(url.href);

  const prefs = AppOptions.getAll(
    OptionKind.PREFERENCE,
    /* defaultOnly = */ true
  );
  if (Object.keys(prefs).length === 0) {
    throw new Error(`No default preferences found in "${dir}".`);
  }
  return prefs;
}

function getDefaultFtl() {
  const content = fs.readFileSync("l10n/en-US/viewer.ftl").toString(),
    stringBuf = [];

  // Strip out comments and line-breaks.
  const regExp = /^\s*#/;
  for (const line of content.split("\n")) {
    if (!line || regExp.test(line)) {
      continue;
    }
    stringBuf.push(line);
  }
  return stringBuf.join("\n");
}

gulp.task("locale", function () {
  const VIEWER_LOCALE_OUTPUT = "web/locale/";

  console.log("\n### Building localization files");

  fs.rmSync(VIEWER_LOCALE_OUTPUT, { recursive: true, force: true });
  fs.mkdirSync(VIEWER_LOCALE_OUTPUT, { recursive: true });

  const subfolders = fs.readdirSync(L10N_DIR);
  subfolders.sort();
  const viewerOutput = Object.create(null);
  const locales = [];
  for (const locale of subfolders) {
    const dirPath = L10N_DIR + locale;
    if (!checkDir(dirPath)) {
      continue;
    }
    if (!/^[a-z]{2,3}(?:-[A-Z]{2})?$/.test(locale)) {
      console.log("Skipping invalid locale: " + locale);
      continue;
    }

    fs.mkdirSync(VIEWER_LOCALE_OUTPUT + "/" + locale, { recursive: true });

    locales.push(locale);

    if (checkFile(dirPath + "/viewer.ftl")) {
      // The L10n-implementations, in the viewer, use lowercase language-codes
      // internally.
      viewerOutput[locale.toLowerCase()] = `${locale}/viewer.ftl`;
    }
  }
  const glob = locales.length === 1 ? locales[0] : `{${locales.join(",")}}`;

  return ordered([
    createStringSource("locale.json", JSON.stringify(viewerOutput)).pipe(
      gulp.dest(VIEWER_LOCALE_OUTPUT)
    ),
    gulp
      .src(`${L10N_DIR}/${glob}/viewer.ftl`, {
        base: L10N_DIR,
        encoding: false,
      })
      .pipe(gulp.dest(VIEWER_LOCALE_OUTPUT)),
  ]);
});

gulp.task("cmaps", async function () {
  const CMAP_INPUT = "external/cmaps";
  const VIEWER_CMAP_OUTPUT = "external/bcmaps";

  console.log("\n### Building cmaps");

  // Testing a file that usually present.
  if (!checkFile(CMAP_INPUT + "/UniJIS-UCS2-H")) {
    console.log("./external/cmaps has no cmap files, download them from:");
    console.log("  https://github.com/adobe-type-tools/cmap-resources");
    throw new Error("cmap files were not found");
  }

  // Remove old bcmap files.
  fs.readdirSync(VIEWER_CMAP_OUTPUT).forEach(file => {
    if (/\.bcmap$/i.test(file)) {
      fs.unlinkSync(VIEWER_CMAP_OUTPUT + "/" + file);
    }
  });

  const { compressCmaps } =
    await import("./external/cmapscompress/compress.mjs");
  compressCmaps(CMAP_INPUT, VIEWER_CMAP_OUTPUT, true);

  // Compress the `.bcmap` files with Brotli, to further reduce their size.
  fs.readdirSync(VIEWER_CMAP_OUTPUT).forEach(file => {
    if (/\.bcmap$/i.test(file)) {
      const src = path.join(VIEWER_CMAP_OUTPUT, file),
        dest = path.join(VIEWER_CMAP_OUTPUT, file + ".br");
      const data = fs.readFileSync(src);

      const br = brotliCompressSync(data, {
        params: {
          [constants.BROTLI_PARAM_MODE]: constants.BROTLI_MODE_TEXT,
          [constants.BROTLI_PARAM_QUALITY]: constants.BROTLI_MAX_QUALITY,
          [constants.BROTLI_PARAM_LGWIN]: constants.BROTLI_MAX_WINDOW_BITS,
          [constants.BROTLI_PARAM_SIZE_HINT]: data.length,
        },
      });
      fs.writeFileSync(dest, br);

      fs.unlinkSync(src); // Finally, remove the `.bcmap` file.
    }
  });
});

function preprocessCSS(source, defines) {
  const outName = getTempFile("~preprocess", ".css");
  preprocess(source, outName, defines);
  const out = fs.readFileSync(outName).toString();
  fs.unlinkSync(outName);

  const i = source.lastIndexOf("/");
  return createStringSource(source.substr(i + 1), out);
}

function discardCommentsCSS() {
  let copyrightNum = 0;

  function remove(comment) {
    // Remove all comments, except the *first* license header.
    if (comment.startsWith("Copyright") && copyrightNum++ === 0) {
      return false;
    }
    return true;
  }
  return postcssDiscardComments({ remove });
}

function preprocessHTML(source, defines) {
  defines = {
    ...defines,
    TESTING: defines.TESTING ?? process.env.TESTING === "true",
  };
  const outName = getTempFile("~preprocess", ".html");
  preprocess(source, outName, defines);
  const out = fs.readFileSync(outName).toString();
  fs.unlinkSync(outName);

  const i = source.lastIndexOf("/");
  return createStringSource(source.substr(i + 1), `${out.trimEnd()}\n`);
}

function buildGeneric(defines, dir) {
  fs.rmSync(dir, { recursive: true, force: true });

  return ordered([
    createMainBundle(defines).pipe(gulp.dest(dir + "build")),
    createWorkerBundle(defines).pipe(gulp.dest(dir + "build")),
    createRendererWorkerBundle(defines).pipe(gulp.dest(dir + "build")),
    createSandboxBundle(defines).pipe(gulp.dest(dir + "build")),
    createWebBundle(defines).pipe(gulp.dest(dir + "web")),
    gulp
      .src(COMMON_WEB_FILES, { base: "web/", encoding: false })
      .pipe(gulp.dest(dir + "web")),
    gulp.src("LICENSE", { encoding: false }).pipe(gulp.dest(dir)),
    gulp
      .src(["web/locale/*/viewer.ftl", "web/locale/locale.json"], {
        base: "web/",
        encoding: false,
      })
      .pipe(gulp.dest(dir + "web")),
    createCMapBundle().pipe(gulp.dest(dir + "web/cmaps")),
    createICCBundle().pipe(gulp.dest(dir + "web/iccs")),
    createStandardFontBundle().pipe(gulp.dest(dir + "web/standard_fonts")),
    createWasmBundle()
      .pipe(brotliCompressFallbacks())
      .pipe(gulp.dest(dir + "web/wasm")),

    preprocessHTML("web/viewer.html", defines).pipe(gulp.dest(dir + "web")),
    preprocessCSS("web/viewer.css", defines)
      .pipe(postcss([discardCommentsCSS(), autoprefixer(AUTOPREFIXER_CONFIG)]))
      .pipe(gulp.dest(dir + "web")),

    gulp
      .src("web/compressed.tracemonkey-pldi-09.pdf", { encoding: false })
      .pipe(gulp.dest(dir + "web")),
  ]);
}

// Builds the generic production viewer that is only compatible with up-to-date
// HTML5 browsers, which implement modern ECMAScript features.
gulp.task(
  "generic",
  gulp.series(
    createBuildNumber,
    "locale",
    function scriptingGeneric() {
      const defines = { ...DEFINES, GENERIC: true };
      return createTemporaryScriptingBundle(defines);
    },
    function createGeneric() {
      console.log("\n### Creating generic viewer");
      const defines = { ...DEFINES, GENERIC: true };

      return buildGeneric(defines, GENERIC_DIR);
    }
  )
);

// Builds the generic production viewer that should be compatible with most
// older HTML5 browsers.
gulp.task(
  "generic-legacy",
  gulp.series(
    createBuildNumber,
    "locale",
    function scriptingGenericLegacy() {
      const defines = { ...DEFINES, GENERIC: true, SKIP_BABEL: false };
      return createTemporaryScriptingBundle(defines);
    },
    function createGenericLegacy() {
      console.log("\n### Creating generic (legacy) viewer");
      const defines = { ...DEFINES, GENERIC: true, SKIP_BABEL: false };

      return buildGeneric(defines, GENERIC_LEGACY_DIR);
    }
  )
);

function buildComponents(defines, dir) {
  fs.rmSync(dir, { recursive: true, force: true });

  const COMPONENTS_IMAGES = ["web/images/*.svg", "web/images/*.gif"];

  return ordered([
    createComponentsBundle(defines).pipe(gulp.dest(dir)),
    gulp
      .src(COMPONENTS_IMAGES, { encoding: false })
      .pipe(gulp.dest(dir + "images")),
    preprocessCSS("web/pdf_viewer.css", defines)
      .pipe(postcss([discardCommentsCSS(), autoprefixer(AUTOPREFIXER_CONFIG)]))
      .pipe(gulp.dest(dir)),
  ]);
}

gulp.task(
  "components",
  gulp.series(createBuildNumber, function createComponents() {
    console.log("\n### Creating generic components");
    const defines = { ...DEFINES, COMPONENTS: true, GENERIC: true };

    return buildComponents(defines, COMPONENTS_DIR);
  })
);

gulp.task(
  "components-legacy",
  gulp.series(createBuildNumber, function createComponentsLegacy() {
    console.log("\n### Creating generic (legacy) components");
    const defines = {
      ...DEFINES,
      COMPONENTS: true,
      GENERIC: true,
      SKIP_BABEL: false,
    };

    return buildComponents(defines, COMPONENTS_LEGACY_DIR);
  })
);

function buildMinified(defines, dir) {
  fs.rmSync(dir, { recursive: true, force: true });

  return ordered([
    createMainBundle(defines).pipe(gulp.dest(dir + "build")),
    createWorkerBundle(defines).pipe(gulp.dest(dir + "build")),
    createRendererWorkerBundle(defines).pipe(gulp.dest(dir + "build")),
    createSandboxBundle(defines).pipe(gulp.dest(dir + "build")),
  ]);
}

gulp.task(
  "minified",
  gulp.series(
    createBuildNumber,
    "locale",
    function scriptingMinified() {
      const defines = { ...DEFINES, MINIFIED: true, GENERIC: true };
      return createTemporaryScriptingBundle(defines);
    },
    function createMinified() {
      console.log("\n### Creating minified viewer");
      const defines = { ...DEFINES, MINIFIED: true, GENERIC: true };

      return buildMinified(defines, MINIFIED_DIR);
    }
  )
);

gulp.task(
  "minified-legacy",
  gulp.series(
    createBuildNumber,
    "locale",
    function scriptingMinifiedLegacy() {
      const defines = {
        ...DEFINES,
        MINIFIED: true,
        GENERIC: true,
        SKIP_BABEL: false,
      };
      return createTemporaryScriptingBundle(defines);
    },
    function createMinifiedLegacy() {
      console.log("\n### Creating minified (legacy) viewer");
      const defines = {
        ...DEFINES,
        MINIFIED: true,
        GENERIC: true,
        SKIP_BABEL: false,
      };

      return buildMinified(defines, MINIFIED_LEGACY_DIR);
    }
  )
);

async function createDefaultPrefsFile() {
  console.log("\n### Building mozilla-central preferences file");

  const defaultFileName = "PdfJsDefaultPrefs.js",
    overrideFileName = "PdfJsOverridePrefs.js";
  const licenseHeader = fs.readFileSync("./src/license_header.js").toString();

  const MODIFICATION_WARNING =
    "// THIS FILE IS GENERATED AUTOMATICALLY, DO NOT EDIT MANUALLY!\n//\n" +
    `// Any overrides should be placed in \`${overrideFileName}\`.\n`;

  const prefs = await getDefaultPreferences("mozcentral/");
  const buf = [];

  for (const name in prefs) {
    let value = prefs[name];

    if (typeof value === "string") {
      value = `"${value}"`;
    }
    buf.push(`pref("pdfjs.${name}", ${value});`);
  }
  buf.sort();
  buf.unshift(licenseHeader, MODIFICATION_WARNING);
  buf.push(`\n#include ${overrideFileName}\n`);

  return createStringSource(defaultFileName, buf.join("\n"));
}

/**
 * Build the mozilla-central staging tree.
 * @param {Set<string>|null} [changedFiles] - Absolute changed paths. Omit for
 *   a full build.
 * @returns {Promise<boolean>} Whether any output was built.
 */
async function buildMozcentral(changedFiles = null) {
  console.log("\n### Building mozilla-central extension");
  const defines = { ...DEFINES, MOZCENTRAL: true };
  const gvDefines = { ...defines, GECKOVIEW: true };

  const MOZCENTRAL_BUILD_DIR = MOZCENTRAL_CONTENT_DIR + "build",
    MOZCENTRAL_WEB_DIR = MOZCENTRAL_CONTENT_DIR + "web";

  const MOZCENTRAL_WEB_FILES = [
    ...COMMON_WEB_FILES,
    "!web/images/toolbarButton-openFile.svg",
  ];
  const MOZCENTRAL_AUTOPREFIXER_CONFIG = {
    overrideBrowserslist: ["last 1 firefox versions"],
  };

  const fullBuild = !changedFiles;
  const changedPaths = fullBuild ? [] : [...changedFiles].map(repoPath);

  if (fullBuild) {
    // Clear the staging tree before a full build.
    fs.rmSync(MOZCENTRAL_DIR, { recursive: true, force: true });
  }

  // Rebuild bundles with unknown or changed Webpack dependencies.
  function bundleChanged(filename) {
    const deps = webpackFileDeps.get(filename);
    return !deps || [...changedFiles].some(file => deps.has(file));
  }
  // Match changed paths for non-Webpack outputs.
  function sourceChanged(regExp) {
    return changedPaths.some(p => regExp.test(p));
  }

  // Map outputs to their builders and watch dependencies.
  const units = [
    { bundle: "pdf.mjs", create: () => createMainBundle(defines) },
    {
      bundle: "pdf.scripting.mjs",
      create: () => createScriptingBundle(defines),
    },
    { bundle: "pdf.worker.mjs", create: () => createWorkerBundle(defines) },
    {
      bundle: "pdf.renderer.mjs",
      create: () => createRendererWorkerBundle(defines),
    },
    {
      files: /^src\/pdf\.sandbox\.external\.js$/,
      create: () => createSandboxExternal(defines),
    },
    {
      bundle: "viewer.mjs",
      dest: MOZCENTRAL_WEB_DIR,
      create: () => createWebBundle(defines),
    },
    {
      bundle: "viewer-geckoview.mjs",
      dest: MOZCENTRAL_WEB_DIR,
      create: () => createGVWebBundle(gvDefines),
    },
    {
      files: /^web\/(images\/|debugger\.)/,
      dest: MOZCENTRAL_WEB_DIR,
      create: () =>
        gulp.src(MOZCENTRAL_WEB_FILES, { base: "web/", encoding: false }),
    },
    {
      files: /^external\/bcmaps\//,
      dest: MOZCENTRAL_WEB_DIR + "/cmaps",
      create: createCMapBundle,
    },
    {
      files: /^external\/iccs\//,
      dest: MOZCENTRAL_WEB_DIR + "/iccs",
      create: createICCBundle,
    },
    {
      files:
        /^external\/hellbox\/(?:.*\.hbgd|unicode\.bin|LICENSE_(?!HELLBOX))/,
      dest: MOZCENTRAL_WEB_DIR + "/standard_fonts",
      create: createStandardFontBundle,
    },
    {
      files: /^external\/(hellbox|jbig2|openjpeg|qcms)\//,
      dest: MOZCENTRAL_WEB_DIR + "/wasm",
      create: () =>
        createWasmBundle({ includeQuickJS: false }).pipe(
          brotliCompressFallbacks()
        ),
    },
    // HTML includes and CSS imports aren't tracked individually; a top-level
    // HTML or CSS change rebuilds both corresponding variants.
    {
      files: /^web\/[^/]+\.html$/,
      dest: MOZCENTRAL_WEB_DIR,
      create: () => preprocessHTML("web/viewer.html", defines),
    },
    {
      files: /^web\/[^/]+\.html$/,
      dest: MOZCENTRAL_WEB_DIR,
      create: () => preprocessHTML("web/viewer-geckoview.html", gvDefines),
    },
    {
      files: /^web\/[^/]+\.css$/,
      dest: MOZCENTRAL_WEB_DIR,
      create: () =>
        preprocessCSS("web/viewer.css", defines).pipe(
          postcss([
            discardCommentsCSS(),
            autoprefixer(MOZCENTRAL_AUTOPREFIXER_CONFIG),
          ])
        ),
    },
    {
      files: /^web\/[^/]+\.css$/,
      dest: MOZCENTRAL_WEB_DIR,
      create: () =>
        preprocessCSS("web/viewer-geckoview.css", gvDefines).pipe(
          postcss([
            discardCommentsCSS(),
            autoprefixer(MOZCENTRAL_AUTOPREFIXER_CONFIG),
          ])
        ),
    },
    {
      files: /^l10n\/en-US\/[^/]+\.ftl$/,
      dest: MOZCENTRAL_L10N_DIR,
      create: () => gulp.src("l10n/en-US/*.ftl", { encoding: false }),
    },
    {
      files: /^LICENSE$/,
      dest: MOZCENTRAL_EXTENSION_DIR,
      create: () => gulp.src("LICENSE", { encoding: false }),
    },
    // PdfJsDefaultPrefs.js is generated from this bundle.
    {
      bundle: "app_options.mjs",
      dest: DEFAULT_PREFERENCES_DIR + "mozcentral/",
      create: () => createDefaultPreferencesBundle(defines, "mozcentral/"),
    },
  ];

  const builds = [];
  let prefsBuildIndex = -1;

  for (const { bundle, files, dest = MOZCENTRAL_BUILD_DIR, create } of units) {
    if (fullBuild || (bundle ? bundleChanged(bundle) : sourceChanged(files))) {
      if (bundle === "app_options.mjs") {
        prefsBuildIndex = builds.length;
      }
      builds.push(
        // Convert synchronous builder errors to rejections so all units settle.
        (async () => {
          await writeToDirectory(create(), dest);
        })()
      );
    }
  }

  if (builds.length === 0) {
    console.log("Nothing to rebuild.");
    return false;
  }

  // Even after a failure, wait for every unit before the next watch build.
  const results = await Promise.allSettled(builds);
  const errors = results
    .filter(({ status }) => status === "rejected")
    .map(({ reason }) => reason);

  // Generate preferences after their bundle succeeds, even if another unit
  // failed: the next build may reuse this bundle before synchronizing.
  if (prefsBuildIndex >= 0 && results[prefsBuildIndex].status === "fulfilled") {
    try {
      await writeToDirectory(
        await createDefaultPrefsFile(),
        MOZCENTRAL_EXTENSION_DIR
      );
    } catch (error) {
      errors.push(error);
    }
  }

  if (errors.length > 0) {
    throw new AggregateError(errors, "The mozilla-central build failed.");
  }
  return true;
}

gulp.task(
  "mozcentral",
  gulp.series(createBuildNumber, async function createMozcentral() {
    try {
      return await buildMozcentral();
    } catch (error) {
      reportBuildFailure(error);
      throw error;
    }
  })
);

function getGeckoDirs() {
  const geckoPath =
    getArgValue("--path") ?? getArgValue("-p") ?? process.env.GECKO_PATH;

  if (!geckoPath) {
    throw new Error(
      "Missing mozilla-central path; please use either the " +
        '"--path <path>" (or "-p <path>") argument or the "GECKO_PATH" ' +
        "environment variable."
    );
  }
  const rootDir = path.resolve(geckoPath);

  if (!checkFile(path.join(rootDir, "mach"))) {
    throw new Error(
      `"${rootDir}" does not appear to be a mozilla-central checkout.`
    );
  }
  const pdfjsDir = path.join(rootDir, "toolkit", "components", "pdfjs"),
    l10nDir = path.join(
      rootDir,
      "toolkit",
      "locales",
      "en-US",
      "toolkit",
      "pdfviewer"
    );

  for (const dir of [pdfjsDir, l10nDir]) {
    if (!checkDir(dir)) {
      throw new Error(`The "${dir}" folder does not exist.`);
    }
  }
  return { rootDir, pdfjsDir, l10nDir };
}

/** Copy `src` if contents differ; otherwise preserve `dest`'s mtime. */
function copyFileIfChanged(src, dest, stats) {
  const data = fs.readFileSync(src);
  let destData;
  try {
    destData = fs.readFileSync(dest);
  } catch (ex) {
    if (ex.code !== "ENOENT" && ex.code !== "EISDIR") {
      throw ex;
    }
  }

  if (destData?.equals(data)) {
    stats.unchanged++;
    return;
  }
  // Remove first because `dest` may be a directory.
  fs.rmSync(dest, { recursive: true, force: true });
  fs.mkdirSync(path.dirname(dest), { recursive: true });
  fs.writeFileSync(dest, data);
  stats.updated.push(dest);
}

/** Mirror regular files and directories from `src`, deleting stale entries. */
function mirrorDir(src, dest, stats) {
  const destStats = fs.lstatSync(dest, { throwIfNoEntry: false });

  if (destStats && !destStats.isDirectory()) {
    fs.rmSync(dest, { recursive: true, force: true });
    stats.removed.push(dest);
  }
  fs.mkdirSync(dest, { recursive: true });

  const srcEntries = fs.readdirSync(src, { withFileTypes: true });
  const srcDirs = new Set(),
    srcFiles = new Set();

  for (const entry of srcEntries) {
    if (entry.isDirectory()) {
      srcDirs.add(entry.name);
    } else if (entry.isFile()) {
      srcFiles.add(entry.name);
    } else {
      throw new Error(
        `Unsupported entry type for "${path.join(src, entry.name)}".`
      );
    }
  }

  // Remove stale entries and entries whose type changed.
  for (const entry of fs.readdirSync(dest, { withFileTypes: true })) {
    if (
      (entry.isDirectory() && srcDirs.has(entry.name)) ||
      (entry.isFile() && srcFiles.has(entry.name))
    ) {
      continue;
    }
    const destPath = path.join(dest, entry.name);
    fs.rmSync(destPath, { recursive: true, force: true });
    stats.removed.push(destPath);
  }

  for (const entry of srcEntries) {
    const srcPath = path.join(src, entry.name),
      destPath = path.join(dest, entry.name);

    if (entry.isDirectory()) {
      mirrorDir(srcPath, destPath, stats);
    } else {
      copyFileIfChanged(srcPath, destPath, stats);
    }
  }
}

function hasWatchArg() {
  // Node consumes "--watch" before gulp can parse it.
  if (process.env.WATCH_REPORT_DEPENDENCIES) {
    throw new Error(
      'The "--watch" option is consumed by Node; please use "-w" instead.'
    );
  }
  return process.argv.includes("-w");
}

function syncMozcentral() {
  const { rootDir, pdfjsDir, l10nDir } = getGeckoDirs();
  console.log(`\n### Updating PDF.js in "${rootDir}"`);

  const stats = { updated: [], removed: [], unchanged: 0 };

  // Mirror `build` and `web`; preserve other `content` entries.
  for (const dir of ["build", "web"]) {
    mirrorDir(
      MOZCENTRAL_CONTENT_DIR + dir,
      path.join(pdfjsDir, "content", dir),
      stats
    );
  }

  for (const file of ["LICENSE", "PdfJsDefaultPrefs.js"]) {
    copyFileIfChanged(
      MOZCENTRAL_EXTENSION_DIR + file,
      path.join(pdfjsDir, file),
      stats
    );
  }

  for (const file of fs.readdirSync(MOZCENTRAL_L10N_DIR)) {
    if (file.endsWith(".ftl")) {
      copyFileIfChanged(
        MOZCENTRAL_L10N_DIR + file,
        path.join(l10nDir, file),
        stats
      );
    }
  }

  for (const filePath of stats.removed) {
    console.log(`  deleted: ${filePath}`);
  }
  for (const filePath of stats.updated) {
    console.log(colorize("green", `  updated: ${filePath}`));
  }
  console.log(
    `\n${stats.updated.length} file(s) updated, ` +
      `${stats.removed.length} file(s) deleted, ` +
      `${stats.unchanged} file(s) unchanged.`
  );
}

function watchMozcentral(done) {
  if (!hasWatchArg()) {
    done();
    return;
  }
  const MOZCENTRAL_SOURCE_FILES = [
    "src/**",
    "web/**",
    "!web/locale/**", // Generated by the `locale` task.
    "!web/wasm/**", // Generated by the `dev-wasm` task.
    "l10n/en-US/*.ftl",
    "external/bcmaps/*",
    "external/hellbox/*",
    "external/iccs/*",
    "external/jbig2/*",
    "external/openjpeg/*",
    "external/qcms/*",
    "LICENSE",
  ];

  console.log("\n### Watching for changes; press Ctrl+C to stop");

  const changedFiles = new Set();
  let timeoutId = null,
    building = false;

  async function rebuild() {
    timeoutId = null;
    if (building) {
      return; // The active rebuild will consume these changes.
    }
    building = true;

    while (changedFiles.size > 0) {
      const files = new Set(changedFiles);
      changedFiles.clear();

      console.log(
        `\n### Changed: ${[...files].map(repoPath).sort().join(", ")}`
      );
      try {
        if (await buildMozcentral(files)) {
          syncMozcentral();
        }
      } catch (error) {
        // Keep watching so a later edit can fix the error.
        reportBuildFailure(error);
      }
    }
    building = false;
  }

  gulp.watch(MOZCENTRAL_SOURCE_FILES).on("all", (event, filePath) => {
    changedFiles.add(path.resolve(filePath));
    // Coalesce event bursts such as branch switches.
    clearTimeout(timeoutId);
    timeoutId = setTimeout(rebuild, 100);
  });

  done();
}

gulp.task(
  "firefox",
  gulp.series(
    "mozcentral",
    function updateMozcentral(done) {
      syncMozcentral();
      done();
    },
    watchMozcentral
  )
);

async function createChromiumPrefsSchema() {
  console.log("\n### Building Chromium preferences file");

  const prefs = await getDefaultPreferences("chromium/");
  const chromiumPrefs = buildPrefsSchema(prefs);

  return createStringSource(
    "preferences_schema.json",
    JSON.stringify(chromiumPrefs, null, 2)
  );
}

gulp.task(
  "chromium",
  gulp.series(
    createBuildNumber,
    "locale",
    function scriptingChromium() {
      const defines = { ...DEFINES, CHROME: true, SKIP_BABEL: false };
      return ordered([
        buildDefaultPreferences(defines, "chromium/"),
        createTemporaryScriptingBundle(defines),
      ]);
    },
    function createChromium() {
      console.log("\n### Building Chromium extension");
      const defines = { ...DEFINES, CHROME: true, SKIP_BABEL: false };

      const CHROME_BUILD_CONTENT_DIR = CHROMIUM_DIR + "content/";

      const CHROME_WEB_FILES = [
        ...COMMON_WEB_FILES,
        "!web/images/toolbarButton-openFile.svg",
      ];

      // Clear out everything in the chrome extension build directory
      fs.rmSync(CHROMIUM_DIR, { recursive: true, force: true });

      const version = getVersionJSON().version;

      return ordered([
        createMainBundle(defines).pipe(
          gulp.dest(CHROME_BUILD_CONTENT_DIR + "build")
        ),
        createWorkerBundle(defines).pipe(
          gulp.dest(CHROME_BUILD_CONTENT_DIR + "build")
        ),
        createRendererWorkerBundle(defines).pipe(
          gulp.dest(CHROME_BUILD_CONTENT_DIR + "build")
        ),
        createSandboxBundle(defines).pipe(
          gulp.dest(CHROME_BUILD_CONTENT_DIR + "build")
        ),
        createWebBundle(defines).pipe(
          gulp.dest(CHROME_BUILD_CONTENT_DIR + "web")
        ),
        gulp
          .src(CHROME_WEB_FILES, { base: "web/", encoding: false })
          .pipe(gulp.dest(CHROME_BUILD_CONTENT_DIR + "web")),

        gulp
          .src(["web/locale/*/viewer.ftl", "web/locale/locale.json"], {
            base: "web/",
            encoding: false,
          })
          .pipe(gulp.dest(CHROME_BUILD_CONTENT_DIR + "web")),
        createCMapBundle().pipe(
          gulp.dest(CHROME_BUILD_CONTENT_DIR + "web/cmaps")
        ),
        createICCBundle().pipe(
          gulp.dest(CHROME_BUILD_CONTENT_DIR + "web/iccs")
        ),
        createStandardFontBundle().pipe(
          gulp.dest(CHROME_BUILD_CONTENT_DIR + "web/standard_fonts")
        ),
        createWasmBundle()
          .pipe(brotliCompressFallbacks())
          .pipe(gulp.dest(CHROME_BUILD_CONTENT_DIR + "web/wasm")),

        preprocessHTML("web/viewer.html", defines).pipe(
          gulp.dest(CHROME_BUILD_CONTENT_DIR + "web")
        ),
        preprocessCSS("web/viewer.css", defines)
          .pipe(
            postcss([discardCommentsCSS(), autoprefixer(AUTOPREFIXER_CONFIG)])
          )
          .pipe(gulp.dest(CHROME_BUILD_CONTENT_DIR + "web")),

        gulp.src("LICENSE", { encoding: false }).pipe(gulp.dest(CHROMIUM_DIR)),
        gulp
          .src("extensions/chromium/manifest.json", { encoding: false })
          .pipe(
            transform("utf8", content =>
              content.toString().replaceAll(/\bPDFJSSCRIPT_VERSION\b/g, version)
            )
          )
          .pipe(gulp.dest(CHROMIUM_DIR)),
        gulp
          .src(["extensions/chromium/**/*.{html,js,css,png}"], {
            base: "extensions/chromium/",
            encoding: false,
          })
          .pipe(gulp.dest(CHROMIUM_DIR)),
      ]);
    },
    async function prefsSchemaChromium() {
      return writeToDirectory(await createChromiumPrefsSchema(), CHROMIUM_DIR);
    }
  )
);

gulp.task("jsdoc", function (done) {
  console.log("\n### Generating documentation (JSDoc)");

  fs.rmSync(JSDOC_BUILD_DIR, { recursive: true, force: true });
  fs.mkdirSync(JSDOC_BUILD_DIR, { recursive: true });

  exec('"node_modules/.bin/jsdoc" -c jsdoc.json', done);
});

gulp.task("types", function (done) {
  console.log("### Generating TypeScript definitions using `tsc`");
  exec(
    `"node_modules/.bin/tsc" --outDir ${TYPES_DIR} --project .`,
    function () {
      exec(`"node_modules/.bin/tsc-alias" --outDir ${TYPES_DIR}`, done);
    }
  );
});

function buildLibHelper(bundleDefines, inputStream, outputDir) {
  const licenseHeader = fs
    .readFileSync("./src/license_header.js")
    .toString()
    .trim()
    .replace(/^\/\*/, "")
    .replace(/\*\/$/, "");

  const ctx = {
    rootPath: __dirname,
    defines: bundleDefines,
    map: {
      "pdfjs-lib": "../pdf.js",
      "display-binary_data_factory": "./binary_data_factory.js",
      "display-network_stream": "./network_stream.js",
      "display-node_utils": "./node_utils.js",
      "fluent-bundle": "../../../node_modules/@fluent/bundle/esm/index.js",
      "fluent-dom": "../../../node_modules/@fluent/dom/esm/index.js",
      "web-null_l10n": "../web/genericl10n.js",
    },
  };
  const enableSourceMaps = bundleDefines.TESTING;
  const enableCoverage = bundleDefines.COVERAGE;

  function preprocessLib(file, _enc, callback) {
    const skipBabel = bundleDefines.SKIP_BABEL;

    if (file.isNull()) {
      return callback(null, file);
    }

    if (file.isStream()) {
      return callback(new Error("Streaming not supported"));
    }

    try {
      // Calculate where the output file will be
      const outputFilePath = path.join(__dirname, outputDir, file.relative);
      const outputFileDir = path.dirname(outputFilePath);
      // Calculate relative path from output directory to source file
      const relativeSourcePath = path.relative(outputFileDir, file.path);

      const plugins = [
        [babelPluginPDFJSPreprocessor, ctx],
        [babelPluginStripSrcPath],
      ];
      if (!skipBabel) {
        plugins.push(["babel-plugin-polyfill-corejs3", BABEL_COREJS_OPTS]);
      }
      if (enableCoverage) {
        plugins.push([
          "babel-plugin-istanbul",
          {
            cwd: __dirname,
            include: ["external/**/*.js", "src/**/*.js", "web/**/*.js"],
          },
        ]);
      }
      plugins.push([babelPluginAddHeaderComment, { header: licenseHeader }]);

      const result = babel.transformSync(file.contents.toString(), {
        ...(enableCoverage && {
          filename: file.path,
          babelrc: false,
          configFile: false,
        }),
        sourceType: "module",
        presets: skipBabel ? undefined : ["@babel/preset-env"],
        plugins,
        targets: BABEL_TARGETS,
        sourceMaps: enableSourceMaps,
        sourceFileName: relativeSourcePath,
      });

      file.contents = Buffer.from(result.code);
      // Attach the source map to the file for gulp-sourcemaps
      if (result.map) {
        file.sourceMap = result.map;
      }

      return callback(null, file);
    } catch (err) {
      return callback(err);
    }
  }

  const pipeline = inputStream.pipe(
    new stream.Transform({
      objectMode: true,
      transform: preprocessLib,
    })
  );
  return pipeline.pipe(
    gulp.dest(outputDir, enableSourceMaps ? { sourcemaps: "." } : {})
  );
}

function buildLib(defines, dir) {
  const versionInfo = getVersionJSON();

  const bundleDefines = {
    ...defines,
    BUNDLE_VERSION: versionInfo.version,
    BUNDLE_BUILD: versionInfo.commit,
    TESTING: defines.TESTING ?? process.env.TESTING === "true",
    COVERAGE:
      defines.COVERAGE ??
      (process.argv.includes("--coverage") ||
        process.argv.includes("--coverage-per-test")),
    DEFAULT_FTL: getDefaultFtl(),
  };

  const enableSourceMaps = bundleDefines.TESTING;
  const inputStream = ordered([
    gulp.src(
      [
        "src/{core,display,shared}/**/*.js",
        "src/{pdf,pdf.worker,pdf.renderer}.js",
      ],
      { base: "src/", encoding: false, sourcemaps: enableSourceMaps }
    ),
    gulp.src(["web/*.js", "!web/{pdfjs,viewer}.js"], {
      base: ".",
      encoding: false,
      sourcemaps: enableSourceMaps,
    }),
    gulp.src("test/unit/*.js", {
      base: ".",
      encoding: false,
      sourcemaps: enableSourceMaps,
    }),
    ...["openjpeg", "qcms", "hellbox", "jbig2", "brotli"].map(name =>
      gulp.src(`external/${name}/*.js`, {
        base: `${name}/`,
        encoding: false,
        sourcemaps: enableSourceMaps,
      })
    ),
  ]);

  return buildLibHelper(bundleDefines, inputStream, dir);
}

gulp.task(
  "lib",
  gulp.series(
    createBuildNumber,
    function scriptingLib() {
      const defines = { ...DEFINES, GENERIC: true, LIB: true };
      return createTemporaryScriptingBundle(defines);
    },
    function createLib() {
      const defines = { ...DEFINES, GENERIC: true, LIB: true };

      return ordered([
        buildLib(defines, "build/lib/"),
        createSandboxBundle(defines).pipe(gulp.dest("build/lib/")),
      ]);
    }
  )
);

gulp.task(
  "lib-legacy",
  gulp.series(
    createBuildNumber,
    function scriptingLibLegacy() {
      const defines = {
        ...DEFINES,
        GENERIC: true,
        LIB: true,
        SKIP_BABEL: false,
      };
      return createTemporaryScriptingBundle(defines);
    },
    function createLibLegacy() {
      const defines = {
        ...DEFINES,
        GENERIC: true,
        LIB: true,
        SKIP_BABEL: false,
      };

      return ordered([
        buildLib(defines, "build/lib-legacy/"),
        createSandboxBundle(defines).pipe(gulp.dest("build/lib-legacy/")),
      ]);
    }
  )
);

function compressPublish({ sourceDirectory, targetFile, modifiedTime }) {
  return gulp
    .src(`${sourceDirectory}**`, { encoding: false })
    .pipe(zip(targetFile, { modifiedTime }))
    .pipe(gulp.dest(BUILD_DIR))
    .on("end", function () {
      console.log(`Built distribution file: ${targetFile}`);
    });
}

gulp.task(
  "publish",
  gulp.series("generic", "generic-legacy", function createPublish(done) {
    const version = JSON.parse(
      fs.readFileSync(BUILD_DIR + "version.json").toString()
    ).version;

    config.stableVersion = version;

    // ZIP files record the modification date of the source files, so if files
    // are generated during the build process the output is not reproducible.
    // To avoid this, the modification dates should be replaced with a fixed
    // date, in our case the last Git commit date, so that builds from identical
    // source code result in bit-by-bit identical output. The `gulp-zip` library
    // supports providing a different modification date to enable reproducible
    // builds. Note that the Git command below outputs the last Git commit date
    // as a Unix timestamp (in seconds since epoch), but the `Date` constructor
    // in JavaScript requires millisecond input, so we have to multiply by 1000.
    const lastCommitTimestamp = execSync('git log --format="%at" -n 1')
      .toString()
      .replace("\n", "");
    const lastCommitDate = new Date(parseInt(lastCommitTimestamp, 10) * 1000);

    return ordered([
      createStringSource(CONFIG_FILE, JSON.stringify(config, null, 2)).pipe(
        gulp.dest(".")
      ),
      compressPublish({
        sourceDirectory: GENERIC_DIR,
        targetFile: `pdfjs-${version}-dist.zip`,
        modifiedTime: lastCommitDate,
      }),
      compressPublish({
        sourceDirectory: GENERIC_LEGACY_DIR,
        targetFile: `pdfjs-${version}-legacy-dist.zip`,
        modifiedTime: lastCommitDate,
      }),
    ]);
  })
);

function setTestEnv(done) {
  process.env.TESTING = "true";
  // TODO: Re-write the relevant unit-tests, which are using `new Date(...)`,
  //       to not required the following time-zone hack since it doesn't work
  //       when the unit-tests are run directly in the browser.
  process.env.TZ = "UTC";
  done();
}

gulp.task(
  "test",
  gulp.series(setTestEnv, "generic", "components", async function runTest() {
    await runTests("unit");
    await runTests("browser");
    await runTests("integration");
  })
);

gulp.task(
  "bottest",
  gulp.series(setTestEnv, "generic", "components", async function runBotTest() {
    await runTests("unit", { bot: true });
    await runTests("browser", { bot: true });
    await runTests("integration");
  })
);

gulp.task(
  "browsertest",
  gulp.series(
    setTestEnv,
    "generic",
    "components",
    async function runBrowserTest() {
      await runTests("browser");
    }
  )
);

gulp.task(
  "botbrowsertest",
  gulp.series(
    setTestEnv,
    "generic",
    "components",
    async function runBotBrowserTest() {
      await runTests("browser", { bot: true });
    }
  )
);

gulp.task(
  "unittest",
  gulp.series(setTestEnv, "generic", async function runUnitTest() {
    await runTests("unit");
  })
);

gulp.task(
  "integrationtest",
  gulp.series(setTestEnv, "generic", async function runIntegrationTest() {
    await runTests("integration");
  })
);

gulp.task(
  "fonttest",
  gulp.series(setTestEnv, async function runFontTest() {
    await runTests("font");
  })
);

gulp.task(
  "makeref",
  gulp.series(setTestEnv, "generic", "components", function runMakeref(done) {
    makeRef(done);
  })
);

gulp.task(
  "botmakeref",
  gulp.series(
    setTestEnv,
    "generic",
    "components",
    function runBotMakeref(done) {
      makeRef(done, true);
    }
  )
);

gulp.task(
  "prefstest",
  gulp.series(
    setTestEnv,
    function genericPrefs() {
      const defines = { ...DEFINES, GENERIC: true };
      return buildDefaultPreferences(defines, "generic/");
    },
    function genericLegacyPrefs() {
      const defines = { ...DEFINES, GENERIC: true, SKIP_BABEL: false };
      return buildDefaultPreferences(defines, "generic-legacy/");
    },
    function chromiumPrefs() {
      const defines = { ...DEFINES, CHROME: true, SKIP_BABEL: false };
      return buildDefaultPreferences(defines, "chromium/");
    },
    function mozcentralPrefs() {
      const defines = { ...DEFINES, MOZCENTRAL: true };
      return buildDefaultPreferences(defines, "mozcentral/");
    },
    async function checkPrefs() {
      console.log("\n### Checking preference generation");

      // Check that the preferences were correctly generated,
      // for all the relevant builds.
      for (const dir of [
        "generic/",
        "generic-legacy/",
        "chromium/",
        "mozcentral/",
      ]) {
        await getDefaultPreferences(dir);
      }

      // Check that all the relevant files can be generated.
      await writeToDirectory(await createChromiumPrefsSchema(), PREFSTEST_DIR);
      await writeToDirectory(await createDefaultPrefsFile(), PREFSTEST_DIR);
    }
  )
);

gulp.task(
  "typestest",
  gulp.series(
    setTestEnv,
    createBuildNumber,
    "types",
    function createTypesTest() {
      return ordered([
        packageJson().pipe(gulp.dest(TYPESTEST_DIR)),
        gulp
          .src("external/dist/**/*", {
            base: "external/dist",
            encoding: false,
            removeBOM: false,
          })
          .pipe(gulp.dest(TYPESTEST_DIR)),
        gulp
          .src(TYPES_DIR + "**/*", { base: TYPES_DIR, encoding: false })
          .pipe(gulp.dest(TYPESTEST_DIR + "types/")),
      ]);
    },
    function runTypesTest(done) {
      exec('"node_modules/.bin/tsc" -p test/types', function (err, stdout) {
        if (err) {
          console.log(`Couldn't compile TypeScript test: ${stdout}`);
        }
        done(err);
      });
    }
  )
);

gulp.task(
  "unittestcli",
  gulp.series(
    setTestEnv,
    "generic-legacy",
    "lib-legacy",
    function downloadPDFs(done) {
      console.log("\n### Downloading PDFs");

      const PDF_TEST = process.env.PDF_TEST || "test_manifest.json";
      const args = ["test.mjs", "--manifestFile=" + PDF_TEST, "--downloadOnly"];

      const testProcess = startNode(args, {
        cwd: TEST_DIR,
        stdio: "inherit",
      });
      testProcess.on("close", function (code) {
        if (code !== 0) {
          done(new Error(`Downloading PDFs failed.`));
        }
        done();
      });
    },
    function runUnitTestCli(done) {
      const useCoverage = process.argv.includes("--coverage");
      const coverageDir =
        getArgValue("--coverage-output") || BUILD_DIR + "coverage";
      const coverageFormats = parseCoverageFormats(
        getArgValue("--coverage-formats")
      );

      const coverageFile = path.join(
        __dirname,
        BUILD_DIR,
        "tmp",
        "unittestcli-coverage.json"
      );
      const env = { ...process.env };
      if (useCoverage) {
        console.log("\n### Running unit tests with code coverage");
        env.UNITTESTCLI_COVERAGE_FILE = coverageFile;
        fs.rmSync(coverageFile, { force: true });
      }

      const options = [
        "--enable-source-maps",
        "node_modules/jasmine/bin/jasmine",
        "JASMINE_CONFIG_PATH=test/unit/clitests.json",
      ];
      const jasmineProcess = startNode(options, { stdio: "inherit", env });

      jasmineProcess.on("close", function (code) {
        if (useCoverage) {
          if (fs.existsSync(coverageFile)) {
            const rawCoverage = JSON.parse(
              fs.readFileSync(coverageFile, "utf8")
            );
            const coverageMap = istanbulCoverage.createCoverageMap(rawCoverage);
            const context = libReport.createContext({
              dir: coverageDir,
              coverageMap,
            });
            for (const fmt of coverageFormats) {
              istanbulReportGenerator
                .create(COVERAGE_FORMAT_TO_REPORTER[fmt], {
                  projectRoot: __dirname,
                })
                .execute(context);
            }
            console.log(
              `\n### Code coverage report generated in ${coverageDir} directory`
            );
          } else {
            console.warn(
              `\n### No coverage data found at ${coverageFile}. Did the build include 'babel-plugin-istanbul'?`
            );
          }
        }
        if (code !== 0) {
          done(new Error("Unit tests failed."));
          return;
        }
        done();
      });
    }
  )
);

gulp.task("benchmark", function (done) {
  console.log("\n### Running benchmarks");

  const args = [
    "node_modules/vitest/vitest.mjs",
    "bench",
    "--run",
    "--config",
    "test/benchmarks/vitest.config.mjs",
  ];
  const outputJson = getArgValue("--output-json");
  if (outputJson) {
    args.push("--outputJson", outputJson);
  }
  const compare = getArgValue("--compare");
  if (compare) {
    args.push("--compare", compare);
  }

  const benchProcess = startNode(args, { stdio: "inherit" });
  benchProcess.on("close", function (code) {
    if (code !== 0) {
      done(new Error("Benchmarks failed."));
      return;
    }
    done();
  });
});

gulp.task("lint-licenses", function (done) {
  console.log("\n### Checking license headers");

  const jsRE =
    /^(?:#[^\n]*\n)?\/\* Copyright \d{4} Mozilla Foundation\n \*\n \* Licensed under the Apache License, Version 2\.0 \(the "License"\);/;
  const htmlRE = /^<!doctype html>\n<!--\nCopyright \d{4} Mozilla Foundation\n/;

  // Files with non-standard license headers (different copyright holder,
  // different license, or missing license).
  const NON_STANDARD_HEADER_FILES = new Set([
    "examples/learning/helloworld.html",
    "examples/learning/helloworld64.html",
    "examples/learning/prevnext.html",
    "examples/node/getinfo.mjs",
    "examples/text-only/index.html",
    "examples/webpack/index.html",
    "examples/webpack/main.mjs",
    "examples/webpack/webpack.config.js",
    "test/add_test.mjs",
    "src/license_header_libre.js",
    "src/shared/murmurhash3.js",
    "test/font/font_core_spec.js",
    "test/font/font_fpgm_spec.js",
    "test/font/font_os2_spec.js",
    "test/font/font_post_spec.js",
    "test/reporter.js",
    "test/resources/reftest-analyzer.css",
    "test/resources/reftest-analyzer.js",
    "test/stats/statcmp.js",
    "web/grab_to_pan.js",
    "web/toggle_button.css",
  ]);

  const errors = [];

  gulp
    .src(
      [
        "{src,web,test,examples}/**/*.{js,mjs,css}",
        "examples/**/*.html",
        "!web/wasm/**/*",
      ],
      { base: "." }
    )
    .on("data", function (file) {
      if (!file.contents) {
        console.warn(
          `  ${file.relative} is a directory, skipping license header check.`
        );
        return;
      }

      const relativePath = file.relative.replaceAll("\\", "/");
      const content = file.contents.toString();
      const re = relativePath.endsWith(".html") ? htmlRE : jsRE;

      if (NON_STANDARD_HEADER_FILES.has(relativePath)) {
        if (re.test(content)) {
          console.warn(
            `  ${relativePath} has a standard license header, but is in the list of non-standard header files list.`
          );
        }
        return;
      }
      if (!re.test(content)) {
        errors.push(relativePath);
      }
    })
    .on("end", function () {
      if (errors.length > 0) {
        for (const file of errors.sort()) {
          console.log(`  Invalid license header: ${file}`);
        }
        done(new Error("License header check failed."));
        return;
      }
      console.log("files checked, no errors found");
      done();
    });
});

gulp.task("lint-chmod", function (done) {
  console.log("\n### Checking executable bit on tracked and untracked files");

  // Files allowed to keep the executable bit (shebang scripts).
  const EXECUTABLE_FILES = new Set([
    ".github/scripts/viewer-preview/check-pr.sh",
    ".github/scripts/viewer-preview/prepare-site.sh",
    ".github/scripts/viewer-preview/publish-pages.sh",
    ".github/scripts/viewer-preview/update-comment.sh",
    "test/chromium/test-telemetry.js",
  ]);

  // Cover untracked-but-not-ignored files too: a `gulp lint` run before
  // `git add` would otherwise miss any 0755 file the developer just created.
  // `-z` is NUL-separated to tolerate whitespace in paths; `--exclude-standard`
  // honours .gitignore / .git/info/exclude / core.excludesFile.
  let lsFiles;
  try {
    lsFiles = execSync("git ls-files -coz --exclude-standard", {
      encoding: "utf8",
    });
  } catch (e) {
    done(e);
    return;
  }

  const offenders = [];
  for (const file of lsFiles.split("\0")) {
    if (!file || EXECUTABLE_FILES.has(file)) {
      continue;
    }
    let stat;
    try {
      stat = fs.lstatSync(file);
    } catch {
      // Tracked file removed from the working tree, broken symlink, etc.
      continue;
    }
    // Skip symlinks (stored as mode 120000) and directories (submodules show
    // up here as 160000 in the index, never as a regular file on disk).
    if (!stat.isFile()) {
      continue;
    }
    // Match git's own heuristic in `ce_permissions`: only the owner execute
    // bit matters when deciding between 100644 and 100755.
    if (stat.mode & 0o100) {
      offenders.push(file);
    }
  }

  if (offenders.length === 0) {
    console.log("files checked, no errors found");
    done();
    return;
  }

  if (!process.argv.includes("--fix")) {
    for (const file of offenders.sort()) {
      console.log(`  Unexpected executable bit: ${file}`);
    }
    done(
      new Error(
        "Executable-bit check failed (run `gulp lint-chmod --fix` to clear)."
      )
    );
    return;
  }

  // Working-tree-only fix, like every other --fix in `gulp lint`: clear the
  // bit on disk and let the user stage the change. On filesystems with
  // `core.filemode=false` (e.g. Windows) this is a no-op and the offending
  // mode must be cleared with `git update-index --chmod=-x` instead.
  for (const file of offenders.sort()) {
    try {
      const { mode } = fs.statSync(file);
      fs.chmodSync(file, mode & ~0o111);
    } catch (e) {
      done(e);
      return;
    }
    console.log(`  cleared executable bit: ${file}`);
  }
  console.log(`done: ${offenders.length} file(s) updated`);
  done();
});

gulp.task("lint-bom", async function () {
  console.log("\n### Checking for UTF-8 byte order marks");

  // Cover untracked-but-not-ignored files too, so a BOM in a freshly created
  // file is caught before `git add`.
  const files = execSync("git ls-files -coz --exclude-standard", {
    encoding: "utf8",
    maxBuffer: 1 << 28,
  })
    .split("\0")
    .filter(Boolean);

  // Only the first three bytes matter: a leading EF BB BF is a UTF-8 BOM.
  async function hasBOM(file) {
    let handle;
    try {
      handle = await fs.promises.open(file, "r");
    } catch {
      return false; // Directory, broken symlink, removed file, etc.
    }
    try {
      const { bytesRead, buffer } = await handle.read(Buffer.alloc(3), 0, 3, 0);
      return (
        bytesRead === 3 &&
        buffer[0] === 0xef &&
        buffer[1] === 0xbb &&
        buffer[2] === 0xbf
      );
    } finally {
      await handle.close();
    }
  }

  // Don't exhaust file descriptors.
  const offenders = [];
  for (let i = 0; i < files.length; i += 256) {
    const chunk = files.slice(i, i + 256);
    const flags = await Promise.all(chunk.map(hasBOM));
    chunk.forEach((file, j) => flags[j] && offenders.push(file));
  }
  offenders.sort();

  if (offenders.length === 0) {
    console.log("files checked, no errors found");
    return;
  }

  if (!process.argv.includes("--fix")) {
    for (const file of offenders) {
      console.log(`  Unexpected byte order mark: ${file}`);
    }
    throw new Error("BOM check failed (run `gulp lint-bom --fix` to clear).");
  }

  // Strip the BOM on disk and let the user stage the change.
  await Promise.all(
    offenders.map(async file => {
      const content = await fs.promises.readFile(file);
      await fs.promises.writeFile(file, content.subarray(3));
      console.log(`  removed byte order mark: ${file}`);
    })
  );
  console.log(`done: ${offenders.length} file(s) updated`);
});

gulp.task("lint", function (done) {
  console.log("\n### Linting JS/CSS/JSON/SVG/HTML files");

  // Ensure that we lint the Firefox specific *.jsm files too.
  const esLintOptions = [
    "node_modules/eslint/bin/eslint",
    ".",
    "--report-unused-disable-directives",
    "--concurrency=auto",
  ];
  if (process.argv.includes("--fix")) {
    esLintOptions.push("--fix");
  }

  const styleLintOptions = [
    "node_modules/stylelint/bin/stylelint.mjs",
    "**/*.css",
    "--report-needless-disables",
  ];
  if (process.argv.includes("--fix")) {
    styleLintOptions.push("--fix");
  }

  // JSON files are intentionally not passed to Prettier here: ESLint already
  // formats them via its prettier/prettier rule (with identical output), and
  // running both in parallel would race on writes in --fix mode.
  const prettierOptions = [
    "node_modules/prettier/bin/prettier.cjs",
    "**/*.html",
  ];
  if (process.argv.includes("--fix")) {
    prettierOptions.push("--log-level", "error", "--write");
  } else {
    prettierOptions.push("--log-level", "warn", "--check");
  }

  const svgLintOptions = [
    "node_modules/svglint/bin/cli.js",
    "**/*.svg",
    "--ci",
    "--no-summary",
  ];

  function runLinter(name, options) {
    return new Promise(resolve => {
      const proc = startNode(options, { stdio: "inherit" });
      proc.on("close", code => {
        resolve(code === 0 ? null : name);
      });
    });
  }

  Promise.all([
    runLinter("ESLint", esLintOptions),
    runLinter("Stylelint", styleLintOptions),
    runLinter("Prettier", prettierOptions),
    runLinter("svglint", svgLintOptions),
  ]).then(results => {
    const failures = results.filter(Boolean);
    if (failures.length) {
      done(new Error(`${failures.join(", ")} failed.`));
      return;
    }

    gulp.series("lint-licenses", "lint-chmod", "lint-bom", "lint-docs")(done);
  });
});

gulp.task(
  "lint-mozcentral",
  gulp.series("mozcentral", function runLintMozcentral(done) {
    console.log("\n### Checking mozilla-central files");

    const styleLintOptions = [
      "../../node_modules/stylelint/bin/stylelint.mjs",
      "**/*.css",
      "--report-needless-disables",
      "--config",
      "../../stylelint-mozcentral.json",
    ];

    const styleLintProcess = startNode(styleLintOptions, {
      stdio: "inherit",
      cwd: BUILD_DIR + "mozcentral/",
    });
    styleLintProcess.on("close", function (styleLintCode) {
      if (styleLintCode !== 0) {
        done(new Error("Stylelint failed."));
        return;
      }
      console.log("files checked, no errors found");
      done();
    });
  })
);

gulp.task("dev-wasm", function () {
  const VIEWER_WASM_OUTPUT = "web/wasm/";

  fs.rmSync(VIEWER_WASM_OUTPUT, { recursive: true, force: true });
  fs.mkdirSync(VIEWER_WASM_OUTPUT, { recursive: true });

  return createWasmBundle()
    .pipe(brotliCompressFallbacks())
    .pipe(gulp.dest(VIEWER_WASM_OUTPUT));
});

gulp.task(
  "dev-sandbox",
  gulp.series(
    function scriptingDevSandbox() {
      const defines = { ...DEFINES, GENERIC: true, TESTING: true };
      return createTemporaryScriptingBundle(defines, {
        disableVersionInfo: true,
      });
    },
    function createDevSandbox() {
      console.log("\n### Building development sandbox");

      const defines = { ...DEFINES, GENERIC: true, TESTING: true };
      const sandboxDir = BUILD_DIR + "dev-sandbox/";

      fs.rmSync(sandboxDir, { recursive: true, force: true });

      return createSandboxBundle(defines, {
        disableVersionInfo: true,
      }).pipe(gulp.dest(sandboxDir));
    }
  )
);

gulp.task(
  "server",
  gulp.parallel(
    function watchLocale() {
      gulp.watch(
        "l10n/**/*.ftl",
        { ignoreInitial: false },
        gulp.series("locale")
      );
    },
    function watchWasm() {
      gulp.watch(
        [
          "external/hellbox/*",
          "external/openjpeg/*",
          "external/qcms/*",
          "external/jbig2/*",
          "external/quickjs/*",
        ],
        { ignoreInitial: false },
        gulp.series("dev-wasm")
      );
    },
    function watchDevSandbox() {
      gulp.watch(
        [
          "src/pdf.{sandbox,sandbox.external,scripting}.js",
          "src/scripting_api/*.js",
          "src/shared/scripting_utils.js",
        ],
        { ignoreInitial: false },
        gulp.series("dev-sandbox")
      );
    },
    async function createServer() {
      console.log("\n### Starting local server");

      let port = 8888;
      const i = process.argv.indexOf("--port");
      if (i >= 0 && i + 1 < process.argv.length) {
        const p = parseInt(process.argv[i + 1], 10);
        if (!isNaN(p)) {
          port = p;
        } else {
          console.error("Invalid port number: using default (8888)");
        }
      }

      let host;
      const j = process.argv.indexOf("--host");
      if (j >= 0 && j + 1 < process.argv.length) {
        host = process.argv[j + 1];
        if (host === "0") {
          host = "0.0.0.0";
        }
      }

      const { WebServer } = await import("./test/webserver.mjs");
      const server = new WebServer({ host, port });
      server.start();
    }
  )
);

gulp.task("clean", function (done) {
  console.log("\n### Cleaning up project builds");

  fs.rmSync(BUILD_DIR, { recursive: true, force: true });
  done();
});

gulp.task("importl10n", async function () {
  const { downloadL10n } = await import("./external/importL10n/locales.mjs");

  console.log("\n### Importing translations from mozilla-central");

  if (!fs.existsSync(L10N_DIR)) {
    fs.mkdirSync(L10N_DIR);
  }
  await downloadL10n(L10N_DIR);
});

gulp.task("check_l10n", function (done) {
  console.log("\n### Checking for unused l10n IDs");

  const checkProcess = startNode(["external/check_l10n/check_l10n.mjs"], {
    stdio: "inherit",
  });
  checkProcess.on("close", function (code) {
    if (code !== 0) {
      done(new Error("check_l10n failed."));
      return;
    }
    done();
  });
});

function createInternalViewerBundle(defines) {
  const viewerFileConfig = createWebpackConfig(defines, {
    filename: "debugger.mjs",
    library: {
      type: "module",
    },
  });
  return createWebpackStream("./web/internal/debugger.js", viewerFileConfig);
}

function buildInternalViewer(defines, dir) {
  fs.rmSync(dir, { recursive: true, force: true });

  return ordered([
    createMainBundle(defines).pipe(gulp.dest(dir + "build")),
    createWorkerBundle(defines).pipe(gulp.dest(dir + "build")),
    createRendererWorkerBundle(defines).pipe(gulp.dest(dir + "build")),
    createInternalViewerBundle(defines).pipe(gulp.dest(dir + "web")),
    preprocessHTML("web/internal/debugger.html", defines).pipe(
      gulp.dest(dir + "web")
    ),
    preprocessCSS("web/internal/debugger.css", defines)
      .pipe(postcss([discardCommentsCSS(), autoprefixer(AUTOPREFIXER_CONFIG)]))
      .pipe(gulp.dest(dir + "web")),
    createCMapBundle().pipe(gulp.dest(dir + "web/cmaps")),
    createICCBundle().pipe(gulp.dest(dir + "web/iccs")),
    createStandardFontBundle().pipe(gulp.dest(dir + "web/standard_fonts")),
    createWasmBundle()
      .pipe(brotliCompressFallbacks())
      .pipe(gulp.dest(dir + "web/wasm")),
  ]);
}

gulp.task(
  "internal-viewer",
  gulp.series(createBuildNumber, function createInternalViewer() {
    console.log("\n### Creating internal viewer");
    const defines = { ...DEFINES, GENERIC: true, INTERNAL_VIEWER: true };
    return buildInternalViewer(defines, INTERNAL_VIEWER_DIR);
  })
);

function ghPagesPrepare() {
  console.log("\n### Creating web site");

  fs.rmSync(GH_PAGES_DIR, { recursive: true, force: true });

  return ordered([
    gulp
      .src(GENERIC_DIR + "**/*", {
        base: GENERIC_DIR,
        encoding: false,
        removeBOM: false,
      })
      .pipe(gulp.dest(GH_PAGES_DIR)),
    gulp
      .src(GENERIC_LEGACY_DIR + "**/*", {
        base: GENERIC_LEGACY_DIR,
        encoding: false,
        removeBOM: false,
      })
      .pipe(gulp.dest(GH_PAGES_DIR + "legacy/")),
    gulp
      .src(JSDOC_BUILD_DIR + "**/*", { base: JSDOC_BUILD_DIR, encoding: false })
      .pipe(gulp.dest(GH_PAGES_DIR + "api/draft/")),
    gulp
      .src(INTERNAL_VIEWER_DIR + "**/*", {
        base: INTERNAL_VIEWER_DIR,
        encoding: false,
        removeBOM: false,
      })
      .pipe(gulp.dest(GH_PAGES_DIR + "internal-viewer/")),
  ]);
}

const DOCS_DIR = "docs/contents/";

// Supported Markdown tokens. Check link rewriting and heading IDs before
// adding more.
const DOCS_MARKDOWN_TOKENS = new Set([
  "code",
  "codespan",
  "heading",
  "html",
  "link",
  "list",
  "list_item",
  "paragraph",
  "space",
  "text",
]);

// Required page metadata.
const DOCS_FRONT_MATTER_KEYS = ["slug", "title"];

/**
 * Return rendered HTML pages keyed by their output path.
 */
function renderDocs() {
  const metadata = {
    sitename: "PDF.js",
    description:
      "A general-purpose, web standards-based platform for parsing and rendering PDFs.",
  };
  const pages = new Map();
  // Plain text of the headings, without inline HTML, for their IDs.
  const headingTextRenderer = new TextRenderer();
  headingTextRenderer.html = () => "";

  for (const file of fs.readdirSync(DOCS_DIR, { recursive: true })) {
    if (!file.endsWith(".md")) {
      continue;
    }
    const filePath = DOCS_DIR + file.replaceAll(path.sep, "/");
    const fail = message => {
      throw new Error(`${filePath}: ${message}`);
    };

    const [, frontMatter, markdown] =
      /^---\n(.*?)\n---\n(.*)$/s.exec(fs.readFileSync(filePath, "utf8")) ??
      fail("missing front matter.");
    const data = {};
    for (const line of frontMatter.split("\n")) {
      const [, key, value] = /^(\w+): (.*)$/.exec(line) ?? [];
      if (!DOCS_FRONT_MATTER_KEYS.includes(key)) {
        fail(`unsupported front matter "${line}".`);
      }
      data[key] = value;
    }
    for (const key of DOCS_FRONT_MATTER_KEYS) {
      if (!(key in data)) {
        fail(`missing "${key}" in the front matter.`);
      }
    }

    const ids = new Set();
    const marked = new Marked({
      renderer: {
        // Preserve existing heading IDs for links such as #download.
        heading({ depth, tokens }) {
          const slug = this.parser
            .parseInline(tokens, headingTextRenderer)
            .toLowerCase()
            .trim()
            .replaceAll(/[^\p{L}\p{N}\s_-]/gu, "")
            .replaceAll(/\s/g, "-");
          let id = slug;
          for (let i = 1; ids.has(id); i++) {
            id = `${slug}-${i}`;
          }
          ids.add(id);
          return `<h${depth} id="${id}">${this.parser.parseInline(tokens)}</h${depth}>\n`;
        },
      },
      walkTokens(token) {
        if (!DOCS_MARKDOWN_TOKENS.has(token.type)) {
          fail(`unsupported Markdown "${token.type}": "${token.raw}".`);
        }
        if (token.type === "code" && token.lang) {
          if (!hljs.getLanguage(token.lang)) {
            fail(`unsupported code language "${token.lang}".`);
          }
          token.text = hljs.highlight(token.text, {
            language: token.lang,
          }).value;
          token.escaped = true;
        }
      },
    });

    const htmlFile = file.replace(/\.md$/, ".html").replaceAll(path.sep, "/");
    const dir = path.posix.dirname(htmlFile);
    const html = layout({
      ...metadata,
      ...data,
      contents: marked.parse(markdown),
    })
      // Rewrite quoted root-relative href/src URLs relative to this page.
      .replaceAll(
        /(\s(?:href|src)=)(["'])\/(?!\/)(.*?)\2/g,
        (_, prefix, quote, url) =>
          `${prefix}${quote}${path.posix.relative(dir, url) || "."}${quote}`
      )
      .replaceAll("STABLE_VERSION", config.stableVersion);

    const absoluteURL =
      /\s(?:href|src|srcset|action|poster|data-src)=["']?\/(?!\/)[^\s>]*/.exec(
        html
      );
    if (absoluteURL) {
      fail(`unsupported absolute local URL:${absoluteURL[0]}`);
    }
    pages.set(htmlFile, html);
  }
  return pages;
}

gulp.task("docs", function (done) {
  fs.cpSync(DOCS_DIR, GH_PAGES_DIR, {
    recursive: true,
    filter: src => !src.endsWith(".md"),
  });
  for (const [htmlFile, html] of renderDocs()) {
    fs.mkdirSync(path.dirname(GH_PAGES_DIR + htmlFile), { recursive: true });
    fs.writeFileSync(GH_PAGES_DIR + htmlFile, html);
  }
  done();
});

gulp.task("lint-docs", function (done) {
  console.log("\n### Checking the web site files");

  renderDocs();
  console.log("files checked, no errors found");
  done();
});

gulp.task(
  "web",
  gulp.series(
    "generic",
    "generic-legacy",
    "internal-viewer",
    "jsdoc",
    ghPagesPrepare,
    "docs"
  )
);

function packageJson() {
  const VERSION = getVersionJSON().version;

  const DIST_NAME = "pdfjs-dist";
  const DIST_DESCRIPTION = "Generic build of Mozilla's PDF.js library.";
  const DIST_KEYWORDS = ["Mozilla", "pdf", "pdf.js"];
  const DIST_HOMEPAGE = "https://mozilla.github.io/pdf.js/";
  const DIST_BUGS_URL = "https://github.com/mozilla/pdf.js/issues";
  const DIST_GIT_URL = "https://github.com/mozilla/pdf.js.git";
  const DIST_LICENSE = "Apache-2.0";

  const npmManifest = {
    name: DIST_NAME,
    version: VERSION,
    main: "build/pdf.mjs",
    types: "types/src/pdf.d.ts",
    description: DIST_DESCRIPTION,
    keywords: DIST_KEYWORDS,
    homepage: DIST_HOMEPAGE,
    bugs: DIST_BUGS_URL,
    license: DIST_LICENSE,
    optionalDependencies: {
      "@napi-rs/canvas": "^1.1.0",
    },
    browser: {
      canvas: false,
      fs: false,
      http: false,
      https: false,
      url: false,
    },
    repository: {
      type: "git",
      url: `git+${DIST_GIT_URL}`,
    },
    engines: {
      node: ">=22.13.0 || >=24",
    },
    scripts: {},
  };

  return createStringSource(
    "package.json",
    JSON.stringify(npmManifest, null, 2)
  );
}

gulp.task(
  "dist",
  gulp.series(
    "generic",
    "generic-legacy",
    "components",
    "components-legacy",
    "minified",
    "minified-legacy",
    "types",
    function createDist() {
      fs.rmSync(DIST_DIR, { recursive: true, force: true });
      fs.mkdirSync(DIST_DIR, { recursive: true });

      return ordered([
        packageJson().pipe(gulp.dest(DIST_DIR)),
        gulp
          .src("external/dist/**/*", {
            base: "external/dist",
            encoding: false,
            removeBOM: false,
          })
          .pipe(gulp.dest(DIST_DIR)),
        gulp
          .src("external/dist/webpack.mjs", {
            encoding: false,
          })
          .pipe(gulp.dest(DIST_DIR + "legacy/")),
        gulp
          .src(GENERIC_DIR + "LICENSE", { encoding: false })
          .pipe(gulp.dest(DIST_DIR)),
        gulp
          .src(GENERIC_DIR + "web/cmaps/**/*", {
            base: GENERIC_DIR + "web",
            encoding: false,
          })
          .pipe(gulp.dest(DIST_DIR)),
        gulp
          .src(GENERIC_DIR + "web/iccs/**/*", {
            base: GENERIC_DIR + "web",
            encoding: false,
          })
          .pipe(gulp.dest(DIST_DIR)),
        gulp
          .src(GENERIC_DIR + "web/standard_fonts/**/*", {
            base: GENERIC_DIR + "web",
            encoding: false,
          })
          .pipe(gulp.dest(DIST_DIR)),
        gulp
          .src(GENERIC_DIR + "web/wasm/**/*", {
            base: GENERIC_DIR + "web",
            encoding: false,
          })
          .pipe(gulp.dest(DIST_DIR)),
        gulp
          .src(
            [
              GENERIC_DIR +
                "build/{pdf,pdf.worker,pdf.sandbox,pdf.renderer}.mjs",
              GENERIC_DIR +
                "build/{pdf,pdf.worker,pdf.sandbox,pdf.renderer}.mjs.map",
            ],
            { encoding: false }
          )
          .pipe(gulp.dest(DIST_DIR + "build/")),
        gulp
          .src(
            [
              GENERIC_LEGACY_DIR +
                "build/{pdf,pdf.worker,pdf.sandbox,pdf.renderer}.mjs",
              GENERIC_LEGACY_DIR +
                "build/{pdf,pdf.worker,pdf.sandbox,pdf.renderer}.mjs.map",
            ],
            { encoding: false }
          )
          .pipe(gulp.dest(DIST_DIR + "legacy/build/")),
        gulp
          .src(
            MINIFIED_DIR +
              "build/{pdf,pdf.worker,pdf.sandbox,pdf.renderer}.min.mjs",
            {
              encoding: false,
            }
          )
          .pipe(gulp.dest(DIST_DIR + "build/")),
        gulp
          .src(
            MINIFIED_LEGACY_DIR +
              "build/{pdf,pdf.worker,pdf.sandbox,pdf.renderer}.min.mjs",
            { encoding: false }
          )
          .pipe(gulp.dest(DIST_DIR + "legacy/build/")),
        gulp
          .src(COMPONENTS_DIR + "**/*", {
            base: COMPONENTS_DIR,
            encoding: false,
          })
          .pipe(gulp.dest(DIST_DIR + "web/")),
        gulp
          .src(COMPONENTS_LEGACY_DIR + "**/*", {
            base: COMPONENTS_LEGACY_DIR,
            encoding: false,
          })
          .pipe(gulp.dest(DIST_DIR + "legacy/web/")),
        gulp
          .src(TYPES_DIR + "**/*", { base: TYPES_DIR, encoding: false })
          .pipe(gulp.dest(DIST_DIR + "types/")),
      ]);
    }
  )
);

gulp.task(
  "dist-install",
  gulp.series("dist", function createDistInstall(done) {
    let distPath = DIST_DIR;
    const opts = {};
    const installPath = process.env.PDFJS_INSTALL_PATH;
    if (installPath) {
      opts.cwd = installPath;
      distPath = path.relative(installPath, distPath);
    }
    safeSpawnSync("npm", ["install", distPath], opts);
    done();
  })
);

gulp.task("externaltest", function (done) {
  console.log("\n### Running test-fixtures.js");
  safeSpawnSync("node", ["external/builder/test-fixtures.mjs"], {
    stdio: "inherit",
  });

  console.log("\n### Running test-fixtures_babel.js");
  safeSpawnSync("node", ["external/builder/test-fixtures_babel.mjs"], {
    stdio: "inherit",
  });

  console.log("\n### Running welch_ttest_spec.js");
  safeSpawnSync(
    "node",
    ["node_modules/jasmine/bin/jasmine", "test/stats/welch_ttest_spec.js"],
    { stdio: "inherit" }
  );
  done();
});