lib/web/preferences.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2020 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @licend The above is the entire license notice for the
 * Javascript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.BasePreferences = void 0;

var _app_options = require("./app_options.js");

let defaultPreferences = null;

function getDefaultPreferences() {
  if (!defaultPreferences) {
    defaultPreferences = Promise.resolve({
      "cursorToolOnLoad": 0,
      "defaultZoomValue": "",
      "disablePageLabels": false,
      "enablePermissions": false,
      "enablePrintAutoRotate": false,
      "enableWebGL": false,
      "externalLinkTarget": 0,
      "historyUpdateUrl": false,
      "ignoreDestinationZoom": false,
      "pdfBugEnabled": false,
      "renderer": "canvas",
      "renderInteractiveForms": true,
      "sidebarViewOnLoad": -1,
      "scrollModeOnLoad": -1,
      "spreadModeOnLoad": -1,
      "textLayerMode": 1,
      "useOnlyCssZoom": false,
      "viewOnLoad": 0,
      "disableAutoFetch": false,
      "disableFontFace": false,
      "disableRange": false,
      "disableStream": false
    });
  }

  return defaultPreferences;
}

class BasePreferences {
  constructor() {
    if (this.constructor === BasePreferences) {
      throw new Error("Cannot initialize BasePreferences.");
    }

    this.prefs = null;
    this._initializedPromise = getDefaultPreferences().then(defaults => {
      Object.defineProperty(this, "defaults", {
        value: Object.freeze(defaults),
        writable: false,
        enumerable: true,
        configurable: false
      });
      this.prefs = Object.assign(Object.create(null), defaults);
      return this._readFromStorage(defaults);
    }).then(prefs => {
      if (!prefs) {
        return;
      }

      for (const name in prefs) {
        const defaultValue = this.defaults[name],
              prefValue = prefs[name];

        if (defaultValue === undefined || typeof prefValue !== typeof defaultValue) {
          continue;
        }

        this.prefs[name] = prefValue;
      }
    });
  }

  async _writeToStorage(prefObj) {
    throw new Error("Not implemented: _writeToStorage");
  }

  async _readFromStorage(prefObj) {
    throw new Error("Not implemented: _readFromStorage");
  }

  async reset() {
    await this._initializedPromise;
    this.prefs = Object.assign(Object.create(null), this.defaults);
    return this._writeToStorage(this.defaults);
  }

  async set(name, value) {
    await this._initializedPromise;
    const defaultValue = this.defaults[name];

    if (defaultValue === undefined) {
      throw new Error(`Set preference: "${name}" is undefined.`);
    } else if (value === undefined) {
      throw new Error("Set preference: no value is specified.");
    }

    const valueType = typeof value;
    const defaultType = typeof defaultValue;

    if (valueType !== defaultType) {
      if (valueType === "number" && defaultType === "string") {
        value = value.toString();
      } else {
        throw new Error(`Set preference: "${value}" is a ${valueType}, ` + `expected a ${defaultType}.`);
      }
    } else {
      if (valueType === "number" && !Number.isInteger(value)) {
        throw new Error(`Set preference: "${value}" must be an integer.`);
      }
    }

    this.prefs[name] = value;
    return this._writeToStorage(this.prefs);
  }

  async get(name) {
    await this._initializedPromise;
    const defaultValue = this.defaults[name];

    if (defaultValue === undefined) {
      throw new Error(`Get preference: "${name}" is undefined.`);
    } else {
      const prefValue = this.prefs[name];

      if (prefValue !== undefined) {
        return prefValue;
      }
    }

    return defaultValue;
  }

  async getAll() {
    await this._initializedPromise;
    return Object.assign(Object.create(null), this.defaults, this.prefs);
  }

}

exports.BasePreferences = BasePreferences;