XPIProvider.jsm

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

"use strict";

/**
 * This file contains most of the logic required to load and run
 * extensions at startup. Anything which is not required immediately at
 * startup should go in XPIInstall.jsm or XPIDatabase.jsm if at all
 * possible, in order to minimize the impact on startup performance.
 */

/**
 * @typedef {number} integer
 */

/* eslint "valid-jsdoc": [2, {requireReturn: false, requireReturnDescription: false, prefer: {return: "returns"}}] */

var EXPORTED_SYMBOLS = ["XPIProvider", "XPIInternal"];

const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
const { XPCOMUtils } = ChromeUtils.import(
  "resource://gre/modules/XPCOMUtils.jsm"
);
const { AddonManager, AddonManagerPrivate } = ChromeUtils.import(
  "resource://gre/modules/AddonManager.jsm"
);

XPCOMUtils.defineLazyModuleGetters(this, {
  AddonSettings: "resource://gre/modules/addons/AddonSettings.jsm",
  AppConstants: "resource://gre/modules/AppConstants.jsm",
  AsyncShutdown: "resource://gre/modules/AsyncShutdown.jsm",
  Dictionary: "resource://gre/modules/Extension.jsm",
  Extension: "resource://gre/modules/Extension.jsm",
  Langpack: "resource://gre/modules/Extension.jsm",
  FileUtils: "resource://gre/modules/FileUtils.jsm",
  JSONFile: "resource://gre/modules/JSONFile.jsm",
  TelemetrySession: "resource://gre/modules/TelemetrySession.jsm",

  XPIDatabase: "resource://gre/modules/addons/XPIDatabase.jsm",
  XPIDatabaseReconcile: "resource://gre/modules/addons/XPIDatabase.jsm",
  XPIInstall: "resource://gre/modules/addons/XPIInstall.jsm",
});

XPCOMUtils.defineLazyServiceGetters(this, {
  aomStartup: [
    "@mozilla.org/addons/addon-manager-startup;1",
    "amIAddonManagerStartup",
  ],
  resProto: [
    "@mozilla.org/network/protocol;1?name=resource",
    "nsISubstitutingProtocolHandler",
  ],
  spellCheck: ["@mozilla.org/spellchecker/engine;1", "mozISpellCheckingEngine"],
  timerManager: [
    "@mozilla.org/updates/timer-manager;1",
    "nsIUpdateTimerManager",
  ],
});

const nsIFile = Components.Constructor(
  "@mozilla.org/file/local;1",
  "nsIFile",
  "initWithPath"
);
const FileInputStream = Components.Constructor(
  "@mozilla.org/network/file-input-stream;1",
  "nsIFileInputStream",
  "init"
);

const PREF_DB_SCHEMA = "extensions.databaseSchema";
const PREF_PENDING_OPERATIONS = "extensions.pendingOperations";
const PREF_EM_ENABLED_SCOPES = "extensions.enabledScopes";
const PREF_EM_STARTUP_SCAN_SCOPES = "extensions.startupScanScopes";
// xpinstall.signatures.required only supported in dev builds
const PREF_XPI_SIGNATURES_REQUIRED = "xpinstall.signatures.required";
const PREF_LANGPACK_SIGNATURES = "extensions.langpacks.signatures.required";
const PREF_INSTALL_DISTRO_ADDONS = "extensions.installDistroAddons";
const PREF_BRANCH_INSTALLED_ADDON = "extensions.installedDistroAddon.";
const PREF_SYSTEM_ADDON_SET = "extensions.systemAddonSet";

const PREF_EM_LAST_APP_BUILD_ID = "extensions.lastAppBuildId";

// Specify a list of valid built-in add-ons to load.
const BUILT_IN_ADDONS_URI = "chrome://browser/content/built_in_addons.json";

const URI_EXTENSION_STRINGS =
  "chrome://mozapps/locale/extensions/extensions.properties";

const DIR_EXTENSIONS = "extensions";
const DIR_SYSTEM_ADDONS = "features";
const DIR_APP_SYSTEM_PROFILE = "system-extensions";
const DIR_STAGE = "staged";
const DIR_TRASH = "trash";

const FILE_XPI_STATES = "addonStartup.json.lz4";

const KEY_PROFILEDIR = "ProfD";
const KEY_ADDON_APP_DIR = "XREAddonAppDir";
const KEY_APP_DISTRIBUTION = "XREAppDist";
const KEY_APP_FEATURES = "XREAppFeat";

const KEY_APP_PROFILE = "app-profile";
const KEY_APP_SYSTEM_PROFILE = "app-system-profile";
const KEY_APP_SYSTEM_ADDONS = "app-system-addons";
const KEY_APP_SYSTEM_DEFAULTS = "app-system-defaults";
const KEY_APP_BUILTINS = "app-builtin";
const KEY_APP_GLOBAL = "app-global";
const KEY_APP_SYSTEM_LOCAL = "app-system-local";
const KEY_APP_SYSTEM_SHARE = "app-system-share";
const KEY_APP_SYSTEM_USER = "app-system-user";
const KEY_APP_TEMPORARY = "app-temporary";

const TEMPORARY_ADDON_SUFFIX = "@temporary-addon";

const STARTUP_MTIME_SCOPES = [
  KEY_APP_GLOBAL,
  KEY_APP_SYSTEM_LOCAL,
  KEY_APP_SYSTEM_SHARE,
  KEY_APP_SYSTEM_USER,
];

const NOTIFICATION_FLUSH_PERMISSIONS = "flush-pending-permissions";
const XPI_PERMISSION = "install";

const XPI_SIGNATURE_CHECK_PERIOD = 24 * 60 * 60;

const DB_SCHEMA = 33;

XPCOMUtils.defineLazyPreferenceGetter(
  this,
  "enabledScopesPref",
  PREF_EM_ENABLED_SCOPES,
  AddonManager.SCOPE_ALL
);

Object.defineProperty(this, "enabledScopes", {
  get() {
    // The profile location is always enabled
    return enabledScopesPref | AddonManager.SCOPE_PROFILE;
  },
});

function encoded(strings, ...values) {
  let result = [];

  for (let [i, string] of strings.entries()) {
    result.push(string);
    if (i < values.length) {
      result.push(encodeURIComponent(values[i]));
    }
  }

  return result.join("");
}

const BOOTSTRAP_REASONS = {
  APP_STARTUP: 1,
  APP_SHUTDOWN: 2,
  ADDON_ENABLE: 3,
  ADDON_DISABLE: 4,
  ADDON_INSTALL: 5,
  ADDON_UNINSTALL: 6,
  ADDON_UPGRADE: 7,
  ADDON_DOWNGRADE: 8,
};

const ALL_EXTERNAL_TYPES = new Set([
  "dictionary",
  "extension",
  "locale",
  "theme",
]);

var gGlobalScope = this;

/**
 * Valid IDs fit this pattern.
 */
var gIDTest = /^(\{[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}\}|[a-z0-9-\._]*\@[a-z0-9-\._]+)$/i;

const { Log } = ChromeUtils.import("resource://gre/modules/Log.jsm");
const LOGGER_ID = "addons.xpi";

// Create a new logger for use by all objects in this Addons XPI Provider module
// (Requires AddonManager.jsm)
var logger = Log.repository.getLogger(LOGGER_ID);

/**
 * Spins the event loop until the given promise resolves, and then eiter returns
 * its success value or throws its rejection value.
 *
 * @param {Promise} promise
 *        The promise to await.
 * @returns {any}
 *        The promise's resolution value, if any.
 */
function awaitPromise(promise) {
  let success = undefined;
  let result = null;

  promise.then(
    val => {
      success = true;
      result = val;
    },
    val => {
      success = false;
      result = val;
    }
  );

  Services.tm.spinEventLoopUntil(
    "XPIProvider.jsm:awaitPromise",
    () => success !== undefined
  );

  if (!success) {
    throw result;
  }
  return result;
}

/**
 * Returns a nsIFile instance for the given path, relative to the given
 * base file, if provided.
 *
 * @param {string} path
 *        The (possibly relative) path of the file.
 * @param {nsIFile} [base]
 *        An optional file to use as a base path if `path` is relative.
 * @returns {nsIFile}
 */
function getFile(path, base = null) {
  // First try for an absolute path, as we get in the case of proxy
  // files. Ideally we would try a relative path first, but on Windows,
  // paths which begin with a drive letter are valid as relative paths,
  // and treated as such.
  try {
    return new nsIFile(path);
  } catch (e) {
    // Ignore invalid relative paths. The only other error we should see
    // here is EOM, and either way, any errors that we care about should
    // be re-thrown below.
  }

  // If the path isn't absolute, we must have a base path.
  let file = base.clone();
  file.appendRelativePath(path);
  return file;
}

/**
 * Returns true if the given file, based on its name, should be treated
 * as an XPI. If the file does not have an appropriate extension, it is
 * assumed to be an unpacked add-on.
 *
 * @param {string} filename
 *        The filename to check.
 * @param {boolean} [strict = false]
 *        If true, this file is in a location maintained by the browser, and
 *        must have a strict, lower-case ".xpi" extension.
 * @returns {boolean}
 *        True if the file is an XPI.
 */
function isXPI(filename, strict) {
  if (strict) {
    return filename.endsWith(".xpi");
  }
  let ext = filename.slice(-4).toLowerCase();
  return ext === ".xpi" || ext === ".zip";
}

/**
 * Returns the extension expected ID for a given file in an extension install
 * directory.
 *
 * @param {nsIFile} file
 *        The extension XPI file or unpacked directory.
 * @returns {AddonId?}
 *        The add-on ID, if valid, or null otherwise.
 */
function getExpectedID(file) {
  let { leafName } = file;
  let id = isXPI(leafName, true) ? leafName.slice(0, -4) : leafName;
  if (gIDTest.test(id)) {
    return id;
  }
  return null;
}

/**
 * Evaluates whether an add-on is allowed to run in safe mode.
 *
 * @param {AddonInternal} aAddon
 *        The add-on to check
 * @returns {boolean}
 *        True if the add-on should run in safe mode
 */
function canRunInSafeMode(aAddon) {
  let location = aAddon.location || null;
  if (!location) {
    return false;
  }

  // Even though the updated system add-ons aren't generally run in safe mode we
  // include them here so their uninstall functions get called when switching
  // back to the default set.

  // TODO product should make the call about temporary add-ons running
  // in safe mode. assuming for now that they are.
  return location.isTemporary || location.isSystem || location.isBuiltin;
}

/**
 * Gets an nsIURI for a file within another file, either a directory or an XPI
 * file. If aFile is a directory then this will return a file: URI, if it is an
 * XPI file then it will return a jar: URI.
 *
 * @param {nsIFile} aFile
 *        The file containing the resources, must be either a directory or an
 *        XPI file
 * @param {string} aPath
 *        The path to find the resource at, "/" separated. If aPath is empty
 *        then the uri to the root of the contained files will be returned
 * @returns {nsIURI}
 *        An nsIURI pointing at the resource
 */
function getURIForResourceInFile(aFile, aPath) {
  if (!isXPI(aFile.leafName)) {
    let resource = aFile.clone();
    if (aPath) {
      aPath.split("/").forEach(part => resource.append(part));
    }

    return Services.io.newFileURI(resource);
  }

  return buildJarURI(aFile, aPath);
}

/**
 * Creates a jar: URI for a file inside a ZIP file.
 *
 * @param {nsIFile} aJarfile
 *        The ZIP file as an nsIFile
 * @param {string} aPath
 *        The path inside the ZIP file
 * @returns {nsIURI}
 *        An nsIURI for the file
 */
function buildJarURI(aJarfile, aPath) {
  let uri = Services.io.newFileURI(aJarfile);
  uri = "jar:" + uri.spec + "!/" + aPath;
  return Services.io.newURI(uri);
}

function maybeResolveURI(uri) {
  if (uri.schemeIs("resource")) {
    return Services.io.newURI(resProto.resolveURI(uri));
  }
  return uri;
}

/**
 * Iterates over the entries in a given directory.
 *
 * Fails silently if the given directory does not exist.
 *
 * @param {nsIFile} aDir
 *        Directory to iterate.
 */
function* iterDirectory(aDir) {
  let dirEnum;
  try {
    dirEnum = aDir.directoryEntries;
    let file;
    while ((file = dirEnum.nextFile)) {
      yield file;
    }
  } catch (e) {
    if (aDir.exists()) {
      logger.warn(`Can't iterate directory ${aDir.path}`, e);
    }
  } finally {
    if (dirEnum) {
      dirEnum.close();
    }
  }
}

/**
 * Migrate data about an addon to match the change made in bug 857456
 * in which "webextension-foo" types were converted to "foo" and the
 * "loader" property was added to distinguish different addon types.
 *
 * @param {Object} addon  The addon info to migrate.
 * @returns {boolean} True if the addon data was converted, false if not.
 */
function migrateAddonLoader(addon) {
  if (addon.hasOwnProperty("loader")) {
    return false;
  }

  switch (addon.type) {
    case "extension":
    case "dictionary":
    case "locale":
    case "theme":
      addon.loader = "bootstrap";
      break;

    case "webextension":
      addon.type = "extension";
      addon.loader = null;
      break;

    case "webextension-dictionary":
      addon.type = "dictionary";
      addon.loader = null;
      break;

    case "webextension-langpack":
      addon.type = "locale";
      addon.loader = null;
      break;

    case "webextension-theme":
      addon.type = "theme";
      addon.loader = null;
      break;

    default:
      logger.warn(`Not converting unknown addon type ${addon.type}`);
  }
  return true;
}

/**
 * The on-disk state of an individual XPI, created from an Object
 * as stored in the addonStartup.json file.
 */
const JSON_FIELDS = Object.freeze([
  "dependencies",
  "enabled",
  "file",
  "loader",
  "lastModifiedTime",
  "path",
  "rootURI",
  "runInSafeMode",
  "signedState",
  "signedDate",
  "startupData",
  "telemetryKey",
  "type",
  "version",
]);

class XPIState {
  constructor(location, id, saved = {}) {
    this.location = location;
    this.id = id;

    // Set default values.
    this.type = "extension";

    for (let prop of JSON_FIELDS) {
      if (prop in saved) {
        this[prop] = saved[prop];
      }
    }

    // Builds prior to be 1512436 did not include the rootURI property.
    // If we're updating from such a build, add that property now.
    if (!("rootURI" in this) && this.file) {
      this.rootURI = getURIForResourceInFile(this.file, "").spec;
    }

    if (!this.telemetryKey) {
      this.telemetryKey = this.getTelemetryKey();
    }

    if (
      saved.currentModifiedTime &&
      saved.currentModifiedTime != this.lastModifiedTime
    ) {
      this.lastModifiedTime = saved.currentModifiedTime;
    } else if (saved.currentModifiedTime === null) {
      this.missing = true;
    }
  }

  // Compatibility shim getters for legacy callers in XPIDatabase.jsm.
  get mtime() {
    return this.lastModifiedTime;
  }
  get active() {
    return this.enabled;
  }

  /**
   * @property {string} path
   *        The full on-disk path of the add-on.
   */
  get path() {
    return this.file && this.file.path;
  }
  set path(path) {
    this.file = path ? getFile(path, this.location.dir) : null;
  }

  /**
   * @property {string} relativePath
   *        The path to the add-on relative to its parent location, or
   *        the full path if its parent location has no on-disk path.
   */
  get relativePath() {
    if (this.location.dir && this.location.dir.contains(this.file)) {
      let path = this.file.getRelativePath(this.location.dir);
      if (AppConstants.platform == "win") {
        path = path.replace(/\//g, "\\");
      }
      return path;
    }
    return this.path;
  }

  /**
   * Returns a JSON-compatible representation of this add-on's state
   * data, to be saved to addonStartup.json.
   *
   * @returns {Object}
   */
  toJSON() {
    let json = {
      dependencies: this.dependencies,
      enabled: this.enabled,
      lastModifiedTime: this.lastModifiedTime,
      loader: this.loader,
      path: this.relativePath,
      rootURI: this.rootURI,
      runInSafeMode: this.runInSafeMode,
      signedState: this.signedState,
      signedDate: this.signedDate,
      telemetryKey: this.telemetryKey,
      version: this.version,
    };
    if (this.type != "extension") {
      json.type = this.type;
    }
    if (this.startupData) {
      json.startupData = this.startupData;
    }
    return json;
  }

  get isWebExtension() {
    return this.loader == null;
  }

  /**
   * Update the last modified time for an add-on on disk.
   *
   * @param {nsIFile} aFile
   *        The location of the add-on.
   * @returns {boolean}
   *       True if the time stamp has changed.
   */
  getModTime(aFile) {
    let mtime = 0;
    try {
      // Clone the file object so we always get the actual mtime, rather
      // than whatever value it may have cached.
      mtime = aFile.clone().lastModifiedTime;
    } catch (e) {
      logger.warn("Can't get modified time of ${path}", aFile, e);
    }

    let changed = mtime != this.lastModifiedTime;
    this.lastModifiedTime = mtime;
    return changed;
  }

  /**
   * Returns a string key by which to identify this add-on in telemetry
   * and crash reports.
   *
   * @returns {string}
   */
  getTelemetryKey() {
    return encoded`${this.id}:${this.version}`;
  }

  get resolvedRootURI() {
    return maybeResolveURI(Services.io.newURI(this.rootURI));
  }

  /**
   * Update the XPIState to match an XPIDatabase entry; if 'enabled' is changed to true,
   * update the last-modified time. This should probably be made async, but for now we
   * don't want to maintain parallel sync and async versions of the scan.
   *
   * Caller is responsible for doing XPIStates.save() if necessary.
   *
   * @param {DBAddonInternal} aDBAddon
   *        The DBAddonInternal for this add-on.
   * @param {boolean} [aUpdated = false]
   *        The add-on was updated, so we must record new modified time.
   */
  syncWithDB(aDBAddon, aUpdated = false) {
    logger.debug("Updating XPIState for " + JSON.stringify(aDBAddon));
    // If the add-on changes from disabled to enabled, we should re-check the modified time.
    // If this is a newly found add-on, it won't have an 'enabled' field but we
    // did a full recursive scan in that case, so we don't need to do it again.
    // We don't use aDBAddon.active here because it's not updated until after restart.
    let mustGetMod = aDBAddon.visible && !aDBAddon.disabled && !this.enabled;

    this.enabled = aDBAddon.visible && !aDBAddon.disabled;

    this.version = aDBAddon.version;
    this.type = aDBAddon.type;
    this.loader = aDBAddon.loader;

    if (aDBAddon.startupData) {
      this.startupData = aDBAddon.startupData;
    }

    this.telemetryKey = this.getTelemetryKey();

    this.dependencies = aDBAddon.dependencies;
    this.runInSafeMode = canRunInSafeMode(aDBAddon);
    this.signedState = aDBAddon.signedState;
    this.signedDate = aDBAddon.signedDate;
    this.file = aDBAddon._sourceBundle;
    this.rootURI = aDBAddon.rootURI;

    if ((aUpdated || mustGetMod) && this.file) {
      this.getModTime(this.file);
      if (this.lastModifiedTime != aDBAddon.updateDate) {
        aDBAddon.updateDate = this.lastModifiedTime;
        if (XPIDatabase.initialized) {
          XPIDatabase.saveChanges();
        }
      }
    }
  }
}

/**
 * Manages the state data for add-ons in a given install location.
 *
 * @param {string} name
 *        The name of the install location (e.g., "app-profile").
 * @param {string | nsIFile | null} path
 *        The on-disk path of the install location. May be null for some
 *        locations which do not map to a specific on-disk path.
 * @param {integer} scope
 *        The scope of add-ons installed in this location.
 * @param {object} [saved]
 *        The persisted JSON state data to restore.
 */
class XPIStateLocation extends Map {
  constructor(name, path, scope, saved) {
    super();

    this.name = name;
    this.scope = scope;
    if (path instanceof Ci.nsIFile) {
      this.dir = path;
      this.path = path.path;
    } else {
      this.path = path;
      this.dir = this.path && new nsIFile(this.path);
    }
    this.staged = {};
    this.changed = false;

    if (saved) {
      this.restore(saved);
    }

    this._installer = undefined;
  }

  hasPrecedence(otherLocation) {
    let locations = Array.from(XPIStates.locations());
    return locations.indexOf(this) <= locations.indexOf(otherLocation);
  }

  get installer() {
    if (this._installer === undefined) {
      this._installer = this.makeInstaller();
    }
    return this._installer;
  }

  makeInstaller() {
    return null;
  }

  restore(saved) {
    if (!this.path && saved.path) {
      this.path = saved.path;
      this.dir = new nsIFile(this.path);
    }
    this.staged = saved.staged || {};
    this.changed = saved.changed || false;

    for (let [id, data] of Object.entries(saved.addons || {})) {
      let xpiState = this._addState(id, data);

      // Make a note that this state was restored from saved data. But
      // only if this location hasn't moved since the last startup,
      // since that causes problems for new system add-on bundles.
      if (!this.path || this.path == saved.path) {
        xpiState.wasRestored = true;
      }
    }
  }

  /**
   * Returns a JSON-compatible representation of this location's state
   * data, to be saved to addonStartup.json.
   *
   * @returns {Object}
   */
  toJSON() {
    let json = {
      addons: {},
      staged: this.staged,
    };

    if (this.path) {
      json.path = this.path;
    }

    if (STARTUP_MTIME_SCOPES.includes(this.name)) {
      json.checkStartupModifications = true;
    }

    for (let [id, addon] of this.entries()) {
      json.addons[id] = addon;
    }
    return json;
  }

  get hasStaged() {
    for (let key in this.staged) {
      return true;
    }
    return false;
  }

  _addState(addonId, saved) {
    let xpiState = new XPIState(this, addonId, saved);
    this.set(addonId, xpiState);
    return xpiState;
  }

  /**
   * Adds state data for the given DB add-on to the DB.
   *
   * @param {DBAddon} addon
   *        The DBAddon to add.
   */
  addAddon(addon) {
    logger.debug(
      "XPIStates adding add-on ${id} in ${location}: ${path}",
      addon
    );

    XPIProvider.persistStartupData(addon);

    let xpiState = this._addState(addon.id, { file: addon._sourceBundle });
    xpiState.syncWithDB(addon, true);

    XPIProvider.addTelemetry(addon.id, { location: this.name });
  }

  /**
   * Remove the XPIState for an add-on and save the new state.
   *
   * @param {string} aId
   *        The ID of the add-on.
   */
  removeAddon(aId) {
    if (this.has(aId)) {
      this.delete(aId);
      XPIStates.save();
    }
  }

  /**
   * Adds stub state data for the local file to the DB.
   *
   * @param {string} addonId
   *        The ID of the add-on represented by the given file.
   * @param {nsIFile} file
   *        The local file or directory containing the add-on.
   * @returns {XPIState}
   */
  addFile(addonId, file) {
    let xpiState = this._addState(addonId, {
      enabled: false,
      file: file.clone(),
    });
    xpiState.getModTime(xpiState.file);
    return xpiState;
  }

  /**
   * Adds metadata for a staged install which should be performed after
   * the next restart.
   *
   * @param {string} addonId
   *        The ID of the staged install. The leaf name of the XPI
   *        within the location's staging directory must correspond to
   *        this ID.
   * @param {object} metadata
   *        The JSON metadata of the parsed install, to be used during
   *        the next startup.
   */
  stageAddon(addonId, metadata) {
    this.staged[addonId] = metadata;
    XPIStates.save();
  }

  /**
   * Removes staged install metadata for the given add-on ID.
   *
   * @param {string} addonId
   *        The ID of the staged install.
   */
  unstageAddon(addonId) {
    if (addonId in this.staged) {
      delete this.staged[addonId];
      XPIStates.save();
    }
  }

  *getStagedAddons() {
    for (let [id, metadata] of Object.entries(this.staged)) {
      yield [id, metadata];
    }
  }

  /**
   * Returns true if the given addon was installed in this location by a text
   * file pointing to its real path.
   *
   * @param {string} aId
   *        The ID of the addon
   * @returns {boolean}
   */
  isLinkedAddon(aId) {
    if (!this.dir) {
      return true;
    }
    return this.has(aId) && !this.dir.contains(this.get(aId).file);
  }

  get isTemporary() {
    return false;
  }

  get isSystem() {
    return false;
  }

  get isBuiltin() {
    return false;
  }

  get hidden() {
    return this.isBuiltin;
  }

  // If this property is false, it does not implement readAddons()
  // interface.  This is used for the temporary and built-in locations
  // that do not correspond to a physical location that can be scanned.
  get enumerable() {
    return true;
  }
}

class TemporaryLocation extends XPIStateLocation {
  /**
   * @param {string} name
   *        The string identifier for the install location.
   */
  constructor(name) {
    super(name, null, AddonManager.SCOPE_TEMPORARY);
    this.locked = false;
  }

  makeInstaller() {
    // Installs are a no-op. We only register that add-ons exist, and
    // run them from their current location.
    return {
      installAddon() {},
      uninstallAddon() {},
    };
  }

  toJSON() {
    return {};
  }

  get isTemporary() {
    return true;
  }

  get enumerable() {
    return false;
  }
}

var TemporaryInstallLocation = new TemporaryLocation(KEY_APP_TEMPORARY);

/**
 * A "location" for addons installed from assets packged into the app.
 */
var BuiltInLocation = new (class _BuiltInLocation extends XPIStateLocation {
  constructor() {
    super(KEY_APP_BUILTINS, null, AddonManager.SCOPE_APPLICATION);
    this.locked = false;
  }

  // The installer object is responsible for moving files around on disk
  // when (un)installing an addon.  Since this location handles only addons
  // that are embedded within the browser, these are no-ops.
  makeInstaller() {
    return {
      installAddon() {},
      uninstallAddon() {},
    };
  }

  get hidden() {
    return false;
  }

  get isBuiltin() {
    return true;
  }

  get enumerable() {
    return false;
  }

  // Builtin addons are never linked, return false
  // here for correct behavior elsewhere.
  isLinkedAddon(/* aId */) {
    return false;
  }
})();

/**
 * An object which identifies a directory install location for add-ons. The
 * location consists of a directory which contains the add-ons installed in the
 * location.
 *
 */
class DirectoryLocation extends XPIStateLocation {
  /**
   * Each add-on installed in the location is either a directory containing the
   * add-on's files or a text file containing an absolute path to the directory
   * containing the add-ons files. The directory or text file must have the same
   * name as the add-on's ID.
   *
   * @param {string} name
   *        The string identifier for the install location.
   * @param {nsIFile} dir
   *        The directory for the install location.
   * @param {integer} scope
   *        The scope of add-ons installed in this location.
   * @param {boolean} [locked = true]
   *        If false, the location accepts new add-on installs.
   * @param {boolean} [system = false]
   *        If true, the location is a system addon location.
   */
  constructor(name, dir, scope, locked = true, system = false) {
    super(name, dir, scope);
    this.locked = locked;
    this._isSystem = system;
  }

  makeInstaller() {
    if (this.locked) {
      return null;
    }
    return new XPIInstall.DirectoryInstaller(this);
  }

  /**
   * Reads a single-line file containing the path to a directory, and
   * returns an nsIFile pointing to that directory, if successful.