PDF.js/web/genericcom.js

/* Copyright 2017 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 { AppOptions } from "./app_options.js";
import { BaseExternalServices } from "./external_services.js";
import { BasePreferences } from "./preferences.js";
import { GenericL10n } from "./genericl10n.js";
import { GenericScripting } from "./generic_scripting.js";
import { SignatureStorage } from "./generic_signature_storage.js";

if (typeof PDFJSDev !== "undefined" && !PDFJSDev.test("GENERIC")) {
  throw new Error(
    'Module "pdfjs-web/genericcom" shall not be used outside GENERIC build.'
  );
}

function initCom(app) {}

class Preferences extends BasePreferences {
  async _writeToStorage(prefObj) {
    localStorage.setItem("pdfjs.preferences", JSON.stringify(prefObj));
  }

  async _readFromStorage(prefObj) {
    return { prefs: JSON.parse(localStorage.getItem("pdfjs.preferences")) };
  }
}

class ExternalServices extends BaseExternalServices {
  async createL10n() {
    return new GenericL10n(AppOptions.get("localeProperties")?.lang);
  }

  createScripting() {
    return new GenericScripting(AppOptions.get("sandboxBundleSrc"));
  }

  createSignatureStorage(eventBus, signal) {
    return new SignatureStorage(eventBus, signal);
  }
}

class MLManager {
  static {
    if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
      this.getFakeMLManager = options => new FakeMLManager(options);
    }
  }

  async isEnabledFor(_name) {
    return false;
  }

  async deleteModel(_service) {
    return null;
  }

  isReady(_name) {
    return false;
  }

  guess(_data) {}

  toggleService(_name, _enabled) {}
}

if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
  // eslint-disable-next-line no-var
  var FakeMLManager = class {
    eventBus = null;

    hasProgress = false;

    constructor({ enableGuessAltText, enableAltTextModelDownload }) {
      this.enableGuessAltText = enableGuessAltText;
      this.enableAltTextModelDownload = enableAltTextModelDownload;
    }

    setEventBus(eventBus, abortSignal) {
      this.eventBus = eventBus;
    }

    async isEnabledFor(_name) {
      return this.enableGuessAltText;
    }

    async deleteModel(_name) {
      this.enableAltTextModelDownload = false;
      return null;
    }

    async loadModel(_name) {}

    async downloadModel(_name) {
      // Simulate downloading the model but with progress.
      // The progress can be seen in the new alt-text dialog.
      this.hasProgress = true;

      const { promise, resolve } = Promise.withResolvers();
      const total = 1e8;
      const end = 1.5 * total;
      const increment = 5e6;
      let loaded = 0;
      const id = setInterval(() => {
        loaded += increment;
        if (loaded <= end) {
          this.eventBus.dispatch("loadaiengineprogress", {
            source: this,
            detail: {
              total,
              totalLoaded: loaded,
              finished: loaded + increment >= end,
            },
          });
          return;
        }
        clearInterval(id);
        this.hasProgress = false;
        this.enableAltTextModelDownload = true;
        resolve(true);
      }, 900);
      return promise;
    }

    isReady(_name) {
      return this.enableAltTextModelDownload;
    }

    guess({ request: { data } }) {
      return new Promise(resolve => {
        setTimeout(() => {
          resolve(data ? { output: "Fake alt text." } : { error: true });
        }, 3000);
      });
    }

    toggleService(_name, enabled) {
      this.enableGuessAltText = enabled;
    }
  };
}

export { ExternalServices, initCom, MLManager, Preferences };