Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1620 insertions, 0 deletions

diff --git a/services/fxaccounts/FxAccounts.sys.mjs b/services/fxaccounts/FxAccounts.sys.mjs
new file mode 100644
index 0000000000..98ba910db0
--- /dev/null
+++ b/services/fxaccounts/FxAccounts.sys.mjs
@@ -0,0 +1,1620 @@
+/* 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/. */
+
+import { PromiseUtils } from "resource://gre/modules/PromiseUtils.sys.mjs";
+
+import { CryptoUtils } from "resource://services-crypto/utils.sys.mjs";
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+import { clearTimeout, setTimeout } from "resource://gre/modules/Timer.sys.mjs";
+
+import { FxAccountsStorageManager } from "resource://gre/modules/FxAccountsStorage.sys.mjs";
+
+const {
+  ERRNO_INVALID_AUTH_TOKEN,
+  ERROR_AUTH_ERROR,
+  ERROR_INVALID_PARAMETER,
+  ERROR_NO_ACCOUNT,
+  ERROR_TO_GENERAL_ERROR_CLASS,
+  ERROR_UNKNOWN,
+  ERROR_UNVERIFIED_ACCOUNT,
+  FXA_PWDMGR_PLAINTEXT_FIELDS,
+  FXA_PWDMGR_REAUTH_ALLOWLIST,
+  FXA_PWDMGR_SECURE_FIELDS,
+  FX_OAUTH_CLIENT_ID,
+  ON_ACCOUNT_STATE_CHANGE_NOTIFICATION,
+  ONLOGIN_NOTIFICATION,
+  ONLOGOUT_NOTIFICATION,
+  ON_PRELOGOUT_NOTIFICATION,
+  ONVERIFIED_NOTIFICATION,
+  ON_DEVICE_DISCONNECTED_NOTIFICATION,
+  POLL_SESSION,
+  PREF_ACCOUNT_ROOT,
+  PREF_LAST_FXA_USER,
+  SERVER_ERRNO_TO_ERROR,
+  log,
+  logPII,
+  logManager,
+} = ChromeUtils.import("resource://gre/modules/FxAccountsCommon.js");
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  FxAccountsClient: "resource://gre/modules/FxAccountsClient.sys.mjs",
+  FxAccountsCommands: "resource://gre/modules/FxAccountsCommands.sys.mjs",
+  FxAccountsConfig: "resource://gre/modules/FxAccountsConfig.sys.mjs",
+  FxAccountsDevice: "resource://gre/modules/FxAccountsDevice.sys.mjs",
+  FxAccountsKeys: "resource://gre/modules/FxAccountsKeys.sys.mjs",
+  FxAccountsProfile: "resource://gre/modules/FxAccountsProfile.sys.mjs",
+  FxAccountsTelemetry: "resource://gre/modules/FxAccountsTelemetry.sys.mjs",
+  Preferences: "resource://gre/modules/Preferences.sys.mjs",
+});
+
+XPCOMUtils.defineLazyGetter(lazy, "mpLocked", () => {
+  return ChromeUtils.importESModule("resource://services-sync/util.sys.mjs")
+    .Utils.mpLocked;
+});
+
+XPCOMUtils.defineLazyGetter(lazy, "ensureMPUnlocked", () => {
+  return ChromeUtils.importESModule("resource://services-sync/util.sys.mjs")
+    .Utils.ensureMPUnlocked;
+});
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "FXA_ENABLED",
+  "identity.fxaccounts.enabled",
+  true
+);
+
+// An AccountState object holds all state related to one specific account.
+// It is considered "private" to the FxAccounts modules.
+// Only one AccountState is ever "current" in the FxAccountsInternal object -
+// whenever a user logs out or logs in, the current AccountState is discarded,
+// making it impossible for the wrong state or state data to be accidentally
+// used.
+// In addition, it has some promise-related helpers to ensure that if an
+// attempt is made to resolve a promise on a "stale" state (eg, if an
+// operation starts, but a different user logs in before the operation
+// completes), the promise will be rejected.
+// It is intended to be used thusly:
+// somePromiseBasedFunction: function() {
+//   let currentState = this.currentAccountState;
+//   return someOtherPromiseFunction().then(
+//     data => currentState.resolve(data)
+//   );
+// }
+// If the state has changed between the function being called and the promise
+// being resolved, the .resolve() call will actually be rejected.
+export function AccountState(storageManager) {
+  this.storageManager = storageManager;
+  this.inFlightTokenRequests = new Map();
+  this.promiseInitialized = this.storageManager
+    .getAccountData()
+    .then(data => {
+      this.oauthTokens = data && data.oauthTokens ? data.oauthTokens : {};
+    })
+    .catch(err => {
+      log.error("Failed to initialize the storage manager", err);
+      // Things are going to fall apart, but not much we can do about it here.
+    });
+}
+
+AccountState.prototype = {
+  oauthTokens: null,
+  whenVerifiedDeferred: null,
+  whenKeysReadyDeferred: null,
+
+  // If the storage manager has been nuked then we are no longer current.
+  get isCurrent() {
+    return this.storageManager != null;
+  },
+
+  abort() {
+    if (this.whenVerifiedDeferred) {
+      this.whenVerifiedDeferred.reject(
+        new Error("Verification aborted; Another user signing in")
+      );
+      this.whenVerifiedDeferred = null;
+    }
+    if (this.whenKeysReadyDeferred) {
+      this.whenKeysReadyDeferred.reject(
+        new Error("Key fetching aborted; Another user signing in")
+      );
+      this.whenKeysReadyDeferred = null;
+    }
+    this.inFlightTokenRequests.clear();
+    return this.signOut();
+  },
+
+  // Clobber all cached data and write that empty data to storage.
+  async signOut() {
+    this.cert = null;
+    this.keyPair = null;
+    this.oauthTokens = null;
+    this.inFlightTokenRequests.clear();
+
+    // Avoid finalizing the storageManager multiple times (ie, .signOut()
+    // followed by .abort())
+    if (!this.storageManager) {
+      return;
+    }
+    const storageManager = this.storageManager;
+    this.storageManager = null;
+
+    await storageManager.deleteAccountData();
+    await storageManager.finalize();
+  },
+
+  // Get user account data. Optionally specify explicit field names to fetch
+  // (and note that if you require an in-memory field you *must* specify the
+  // field name(s).)
+  getUserAccountData(fieldNames = null) {
+    if (!this.isCurrent) {
+      return Promise.reject(new Error("Another user has signed in"));
+    }
+    return this.storageManager.getAccountData(fieldNames).then(result => {
+      return this.resolve(result);
+    });
+  },
+
+  async updateUserAccountData(updatedFields) {
+    if ("uid" in updatedFields) {
+      const existing = await this.getUserAccountData(["uid"]);
+      if (existing.uid != updatedFields.uid) {
+        throw new Error(
+          "The specified credentials aren't for the current user"
+        );
+      }
+      // We need to nuke uid as storage will complain if we try and
+      // update it (even when the value is the same)
+      updatedFields = Cu.cloneInto(updatedFields, {}); // clone it first
+      delete updatedFields.uid;
+    }
+    if (!this.isCurrent) {
+      return Promise.reject(new Error("Another user has signed in"));
+    }
+    return this.storageManager.updateAccountData(updatedFields);
+  },
+
+  resolve(result) {
+    if (!this.isCurrent) {
+      log.info(
+        "An accountState promise was resolved, but was actually rejected" +
+          " due to a different user being signed in. Originally resolved" +
+          " with",
+        result
+      );
+      return Promise.reject(new Error("A different user signed in"));
+    }
+    return Promise.resolve(result);
+  },
+
+  reject(error) {
+    // It could be argued that we should just let it reject with the original
+    // error - but this runs the risk of the error being (eg) a 401, which
+    // might cause the consumer to attempt some remediation and cause other
+    // problems.
+    if (!this.isCurrent) {
+      log.info(
+        "An accountState promise was rejected, but we are ignoring that " +
+          "reason and rejecting it due to a different user being signed in. " +
+          "Originally rejected with",
+        error
+      );
+      return Promise.reject(new Error("A different user signed in"));
+    }
+    return Promise.reject(error);
+  },
+
+  // Abstractions for storage of cached tokens - these are all sync, and don't
+  // handle revocation etc - it's just storage (and the storage itself is async,
+  // but we don't return the storage promises, so it *looks* sync)
+  // These functions are sync simply so we can handle "token races" - when there
+  // are multiple in-flight requests for the same scope, we can detect this
+  // and revoke the redundant token.
+
+  // A preamble for the cache helpers...
+  _cachePreamble() {
+    if (!this.isCurrent) {
+      throw new Error("Another user has signed in");
+    }
+  },
+
+  // Set a cached token. |tokenData| must have a 'token' element, but may also
+  // have additional fields.
+  // The 'get' functions below return the entire |tokenData| value.
+  setCachedToken(scopeArray, tokenData) {
+    this._cachePreamble();
+    if (!tokenData.token) {
+      throw new Error("No token");
+    }
+    let key = getScopeKey(scopeArray);
+    this.oauthTokens[key] = tokenData;
+    // And a background save...
+    this._persistCachedTokens();
+  },
+
+  // Return data for a cached token or null (or throws on bad state etc)
+  getCachedToken(scopeArray) {
+    this._cachePreamble();
+    let key = getScopeKey(scopeArray);
+    let result = this.oauthTokens[key];
+    if (result) {
+      // later we might want to check an expiry date - but we currently
+      // have no such concept, so just return it.
+      log.trace("getCachedToken returning cached token");
+      return result;
+    }
+    return null;
+  },
+
+  // Remove a cached token from the cache.  Does *not* revoke it from anywhere.
+  // Returns the entire token entry if found, null otherwise.
+  removeCachedToken(token) {
+    this._cachePreamble();
+    let data = this.oauthTokens;
+    for (let [key, tokenValue] of Object.entries(data)) {
+      if (tokenValue.token == token) {
+        delete data[key];
+        // And a background save...
+        this._persistCachedTokens();
+        return tokenValue;
+      }
+    }
+    return null;
+  },
+
+  // A hook-point for tests.  Returns a promise that's ignored in most cases
+  // (notable exceptions are tests and when we explicitly are saving the entire
+  // set of user data.)
+  _persistCachedTokens() {
+    this._cachePreamble();
+    return this.updateUserAccountData({ oauthTokens: this.oauthTokens }).catch(
+      err => {
+        log.error("Failed to update cached tokens", err);
+      }
+    );
+  },
+};
+
+/* Given an array of scopes, make a string key by normalizing. */
+function getScopeKey(scopeArray) {
+  let normalizedScopes = scopeArray.map(item => item.toLowerCase());
+  return normalizedScopes.sort().join("|");
+}
+
+function getPropertyDescriptor(obj, prop) {
+  return (
+    Object.getOwnPropertyDescriptor(obj, prop) ||
+    getPropertyDescriptor(Object.getPrototypeOf(obj), prop)
+  );
+}
+
+/**
+ * Copies properties from a given object to another object.
+ *
+ * @param from (object)
+ *        The object we read property descriptors from.
+ * @param to (object)
+ *        The object that we set property descriptors on.
+ * @param thisObj (object)
+ *        The object that will be used to .bind() all function properties we find to.
+ * @param keys ([...])
+ *        The names of all properties to be copied.
+ */
+function copyObjectProperties(from, to, thisObj, keys) {
+  for (let prop of keys) {
+    // Look for the prop in the prototype chain.
+    let desc = getPropertyDescriptor(from, prop);
+
+    if (typeof desc.value == "function") {
+      desc.value = desc.value.bind(thisObj);
+    }
+
+    if (desc.get) {
+      desc.get = desc.get.bind(thisObj);
+    }
+
+    if (desc.set) {
+      desc.set = desc.set.bind(thisObj);
+    }
+
+    Object.defineProperty(to, prop, desc);
+  }
+}
+
+/**
+ * The public API.
+ *
+ * TODO - *all* non-underscore stuff here should have sphinx docstrings so
+ * that docs magically appear on https://firefox-source-docs.mozilla.org/
+ * (although |./mach doc| is broken on windows (bug 1232403) and on Linux for
+ * markh (some obscure npm issue he gave up on) - so later...)
+ */
+export class FxAccounts {
+  constructor(mocks = null) {
+    this._internal = new FxAccountsInternal();
+    if (mocks) {
+      // it's slightly unfortunate that we need to mock the main "internal" object
+      // before calling initialize, primarily so a mock `newAccountState` is in
+      // place before initialize calls it, but we need to initialize the
+      // "sub-object" mocks after. This can probably be fixed, but whatever...
+      copyObjectProperties(
+        mocks,
+        this._internal,
+        this._internal,
+        Object.keys(mocks).filter(key => !["device", "commands"].includes(key))
+      );
+    }
+    this._internal.initialize();
+    // allow mocking our "sub-objects" too.
+    if (mocks) {
+      for (let subobject of [
+        "currentAccountState",
+        "keys",
+        "fxaPushService",
+        "device",
+        "commands",
+      ]) {
+        if (typeof mocks[subobject] == "object") {
+          copyObjectProperties(
+            mocks[subobject],
+            this._internal[subobject],
+            this._internal[subobject],
+            Object.keys(mocks[subobject])
+          );
+        }
+      }
+    }
+  }
+
+  get commands() {
+    return this._internal.commands;
+  }
+
+  static get config() {
+    return lazy.FxAccountsConfig;
+  }
+
+  get device() {
+    return this._internal.device;
+  }
+
+  get keys() {
+    return this._internal.keys;
+  }
+
+  get telemetry() {
+    return this._internal.telemetry;
+  }
+
+  _withCurrentAccountState(func) {
+    return this._internal.withCurrentAccountState(func);
+  }
+
+  _withVerifiedAccountState(func) {
+    return this._internal.withVerifiedAccountState(func);
+  }
+
+  _withSessionToken(func, mustBeVerified = true) {
+    return this._internal.withSessionToken(func, mustBeVerified);
+  }
+
+  /**
+   * Returns an array listing all the OAuth clients connected to the
+   * authenticated user's account. This includes browsers and web sessions - no
+   * filtering is done of the set returned by the FxA server.
+   *
+   * @typedef {Object} AttachedClient
+   * @property {String} id - OAuth `client_id` of the client.
+   * @property {Number} lastAccessedDaysAgo - How many days ago the client last
+   *    accessed the FxA server APIs.
+   *
+   * @returns {Array.<AttachedClient>} A list of attached clients.
+   */
+  async listAttachedOAuthClients() {
+    // We expose last accessed times in 'days ago'
+    const ONE_DAY = 24 * 60 * 60 * 1000;
+
+    return this._withSessionToken(async sessionToken => {
+      const response = await this._internal.fxAccountsClient.attachedClients(
+        sessionToken
+      );
+      const attachedClients = response.body;
+      const timestamp = response.headers["x-timestamp"];
+      const now =
+        timestamp !== undefined
+          ? new Date(parseInt(timestamp, 10))
+          : Date.now();
+      return attachedClients.map(client => {
+        const daysAgo = client.lastAccessTime
+          ? Math.max(Math.floor((now - client.lastAccessTime) / ONE_DAY), 0)
+          : null;
+        return {
+          id: client.clientId,
+          lastAccessedDaysAgo: daysAgo,
+        };
+      });
+    });
+  }
+
+  /**
+   * Get an OAuth token for the user.
+   *
+   * @param options
+   *        {
+   *          scope: (string/array) the oauth scope(s) being requested. As a
+   *                 convenience, you may pass a string if only one scope is
+   *                 required, or an array of strings if multiple are needed.
+   *          ttl: (number) OAuth token TTL in seconds.
+   *        }
+   *
+   * @return Promise.<string | Error>
+   *        The promise resolves the oauth token as a string or rejects with
+   *        an error object ({error: ERROR, details: {}}) of the following:
+   *          INVALID_PARAMETER
+   *          NO_ACCOUNT
+   *          UNVERIFIED_ACCOUNT
+   *          NETWORK_ERROR
+   *          AUTH_ERROR
+   *          UNKNOWN_ERROR
+   */
+  async getOAuthToken(options = {}) {
+    try {
+      return await this._internal.getOAuthToken(options);
+    } catch (err) {
+      throw this._internal._errorToErrorClass(err);
+    }
+  }
+
+  /**
+   * Remove an OAuth token from the token cache. Callers should call this
+   * after they determine a token is invalid, so a new token will be fetched
+   * on the next call to getOAuthToken().
+   *
+   * @param options
+   *        {
+   *          token: (string) A previously fetched token.
+   *        }
+   * @return Promise.<undefined> This function will always resolve, even if
+   *         an unknown token is passed.
+   */
+  removeCachedOAuthToken(options) {
+    return this._internal.removeCachedOAuthToken(options);
+  }
+
+  /**
+   * Get details about the user currently signed in to Firefox Accounts.
+   *
+   * @return Promise
+   *        The promise resolves to the credentials object of the signed-in user:
+   *        {
+   *          email: String: The user's email address
+   *          uid: String: The user's unique id
+   *          verified: Boolean: email verification status
+   *          displayName: String or null if not known.
+   *          avatar: URL of the avatar for the user. May be the default
+   *                  avatar, or null in edge-cases (eg, if there's an account
+   *                  issue, etc
+   *          avatarDefault: boolean - whether `avatar` is specific to the user
+   *                         or the default avatar.
+   *        }
+   *
+   *        or null if no user is signed in. This function never fails except
+   *        in pathological cases (eg, file-system errors, etc)
+   */
+  getSignedInUser() {
+    // Note we don't return the session token, but use it to see if we
+    // should fetch the profile.
+    const ACCT_DATA_FIELDS = ["email", "uid", "verified", "sessionToken"];
+    const PROFILE_FIELDS = ["displayName", "avatar", "avatarDefault"];
+    return this._withCurrentAccountState(async currentState => {
+      const data = await currentState.getUserAccountData(ACCT_DATA_FIELDS);
+      if (!data) {
+        return null;
+      }
+      if (!lazy.FXA_ENABLED) {
+        await this.signOut();
+        return null;
+      }
+      if (!this._internal.isUserEmailVerified(data)) {
+        // If the email is not verified, start polling for verification,
+        // but return null right away.  We don't want to return a promise
+        // that might not be fulfilled for a long time.
+        this._internal.startVerifiedCheck(data);
+      }
+
+      let profileData = null;
+      if (data.sessionToken) {
+        delete data.sessionToken;
+        try {
+          profileData = await this._internal.profile.getProfile();
+        } catch (error) {
+          log.error("Could not retrieve profile data", error);
+        }
+      }
+      for (let field of PROFILE_FIELDS) {
+        data[field] = profileData ? profileData[field] : null;
+      }
+      // and email is a special case - if we have profile data we prefer the
+      // email from that, as the email we stored for the account itself might
+      // not have been updated if the email changed since the user signed in.
+      if (profileData && profileData.email) {
+        data.email = profileData.email;
+      }
+      return data;
+    });
+  }
+
+  /**
+   * Checks the status of the account. Resolves with Promise<boolean>, where
+   * true indicates the account status is OK and false indicates there's some
+   * issue with the account - either that there's no user currently signed in,
+   * the entire account has been deleted (in which case there will be no user
+   * signed in after this call returns), or that the user must reauthenticate (in
+   * which case `this.hasLocalSession()` will return `false` after this call
+   * returns).
+   *
+   * Typically used when some external code which uses, for example, oauth tokens
+   * received a 401 error using the token, or that this external code has some
+   * other reason to believe the account status may be bad. Note that this will
+   * be called automatically in many cases - for example, if calls to fetch the
+   * profile, or fetch keys, etc return a 401, there's no need to call this
+   * function.
+   *
+   * Because this hits the server, you should only call this method when you have
+   * good reason to believe the session very recently became invalid (eg, because
+   * you saw an auth related exception from a remote service.)
+   */
+  checkAccountStatus() {
+    // Note that we don't use _withCurrentAccountState here because that will
+    // cause an exception to be thrown if we end up signing out due to the
+    // account not existing, which isn't what we want here.
+    let state = this._internal.currentAccountState;
+    return this._internal.checkAccountStatus(state);
+  }
+
+  /**
+   * Checks if we have a valid local session state for the current account.
+   *
+   * @return Promise
+   *        Resolves with a boolean, with true indicating that we appear to
+   *        have a valid local session, or false if we need to reauthenticate
+   *        with the content server to obtain one.
+   *        Note that this only checks local state, although typically that's
+   *        OK, because we drop the local session information whenever we detect
+   *        we are in this state. However, see checkAccountStatus() for a way to
+   *        check the account and session status with the server, which can be
+   *        considered the canonical, albiet expensive, way to determine the
+   *        status of the account.
+   */
+  hasLocalSession() {
+    return this._withCurrentAccountState(async state => {
+      let data = await state.getUserAccountData(["sessionToken"]);
+      return !!(data && data.sessionToken);
+    });
+  }
+
+  /** Returns a promise that resolves to true if we can currently connect (ie,
+   *  sign in, or re-connect after a password change) to a Firefox Account.
+   *  If this returns false, the caller can assume that some UI was shown
+   *  which tells the user why we could not connect.
+   *
+   *  Currently, the primary password being locked is the only reason why
+   *  this returns false, and in this scenario, the primary password unlock
+   *  dialog will have been shown.
+   *
+   *  This currently doesn't need to return a promise, but does so that
+   *  future enhancements, such as other explanatory UI which requires
+   *  async can work without modification of the call-sites.
+   */
+  static canConnectAccount() {
+    return Promise.resolve(!lazy.mpLocked() || lazy.ensureMPUnlocked());
+  }
+
+  /**
+   * Send a message to a set of devices in the same account
+   *
+   * @param deviceIds: (null/string/array) The device IDs to send the message to.
+   *                   If null, will be sent to all devices.
+   *
+   * @param excludedIds: (null/string/array) If deviceIds is null, this may
+   *                     list device IDs which should not receive the message.
+   *
+   * @param payload: (object) The payload, which will be JSON.stringified.
+   *
+   * @param TTL: How long the message should be retained before it is discarded.
+   */
+  // XXX - used only by sync to tell other devices that the clients collection
+  // has changed so they should sync asap. The API here is somewhat vague (ie,
+  // "an object"), but to be useful across devices, the payload really needs
+  // formalizing. We should try and do something better here.
+  notifyDevices(deviceIds, excludedIds, payload, TTL) {
+    return this._internal.notifyDevices(deviceIds, excludedIds, payload, TTL);
+  }
+
+  /**
+   * Resend the verification email for the currently signed-in user.
+   *
+   */
+  resendVerificationEmail() {
+    return this._withSessionToken((token, currentState) => {
+      this._internal.startPollEmailStatus(currentState, token, "start");
+      return this._internal.fxAccountsClient.resendVerificationEmail(token);
+    }, false);
+  }
+
+  async signOut(localOnly) {
+    // Note that we do not use _withCurrentAccountState here, otherwise we
+    // end up with an exception due to the user signing out before the call is
+    // complete - but that's the entire point of this method :)
+    return this._internal.signOut(localOnly);
+  }
+
+  // XXX - we should consider killing this - the only reason it is public is
+  // so that sync can change it when it notices the device name being changed,
+  // and that could probably be replaced with a pref observer.
+  updateDeviceRegistration() {
+    return this._withCurrentAccountState(_ => {
+      return this._internal.updateDeviceRegistration();
+    });
+  }
+
+  // we should try and kill this too.
+  whenVerified(data) {
+    return this._withCurrentAccountState(_ => {
+      return this._internal.whenVerified(data);
+    });
+  }
+
+  /**
+   * Generate a log file for the FxA action that just completed
+   * and refresh the input & output streams.
+   */
+  async flushLogFile() {
+    const logType = await logManager.resetFileLog();
+    if (logType == logManager.ERROR_LOG_WRITTEN) {
+      console.error(
+        "FxA encountered an error - see about:sync-log for the log file."
+      );
+    }
+    Services.obs.notifyObservers(null, "service:log-manager:flush-log-file");
+  }
+}
+
+var FxAccountsInternal = function () {};
+
+/**
+ * The internal API's prototype.
+ */
+FxAccountsInternal.prototype = {
+  // Make a local copy of this constant so we can mock it in testing
+  POLL_SESSION,
+
+  // The timeout (in ms) we use to poll for a verified mail for the first
+  // VERIFICATION_POLL_START_SLOWDOWN_THRESHOLD minutes if the user has
+  // logged-in in this session.
+  VERIFICATION_POLL_TIMEOUT_INITIAL: 60000, // 1 minute.
+  // All the other cases (> 5 min, on restart etc).
+  VERIFICATION_POLL_TIMEOUT_SUBSEQUENT: 5 * 60000, // 5 minutes.
+  // After X minutes, the polling will slow down to _SUBSEQUENT if we have
+  // logged-in in this session.
+  VERIFICATION_POLL_START_SLOWDOWN_THRESHOLD: 5,
+
+  _fxAccountsClient: null,
+
+  // All significant initialization should be done in this initialize() method
+  // to help with our mocking story.
+  initialize() {
+    XPCOMUtils.defineLazyGetter(this, "fxaPushService", function () {
+      return Cc["@mozilla.org/fxaccounts/push;1"].getService(
+        Ci.nsISupports
+      ).wrappedJSObject;
+    });
+
+    this.keys = new lazy.FxAccountsKeys(this);
+
+    if (!this.observerPreloads) {
+      // A registry of promise-returning functions that `notifyObservers` should
+      // call before sending notifications. Primarily used so parts of Firefox
+      // which have yet to load for performance reasons can be force-loaded, and
+      // thus not miss notifications.
+      this.observerPreloads = [
+        // Sync
+        () => {
+          let { Weave } = ChromeUtils.importESModule(
+            "resource://services-sync/main.sys.mjs"
+          );
+          return Weave.Service.promiseInitialized;
+        },
+      ];
+    }
+
+    this.currentTimer = null;
+    // This object holds details about, and storage for, the current user. It
+    // is replaced when a different user signs in. Instead of using it directly,
+    // you should try and use `withCurrentAccountState`.
+    this.currentAccountState = this.newAccountState();
+  },
+
+  async withCurrentAccountState(func) {
+    const state = this.currentAccountState;
+    let result;
+    try {
+      result = await func(state);
+    } catch (ex) {
+      return state.reject(ex);
+    }
+    return state.resolve(result);
+  },
+
+  async withVerifiedAccountState(func) {
+    return this.withCurrentAccountState(async state => {
+      let data = await state.getUserAccountData();
+      if (!data) {
+        // No signed-in user
+        throw this._error(ERROR_NO_ACCOUNT);
+      }
+
+      if (!this.isUserEmailVerified(data)) {
+        // Signed-in user has not verified email
+        throw this._error(ERROR_UNVERIFIED_ACCOUNT);
+      }
+      return func(state);
+    });
+  },
+
+  async withSessionToken(func, mustBeVerified = true) {
+    const state = this.currentAccountState;
+    let data = await state.getUserAccountData();
+    if (!data) {
+      // No signed-in user
+      throw this._error(ERROR_NO_ACCOUNT);
+    }
+
+    if (mustBeVerified && !this.isUserEmailVerified(data)) {
+      // Signed-in user has not verified email
+      throw this._error(ERROR_UNVERIFIED_ACCOUNT);
+    }
+
+    if (!data.sessionToken) {
+      throw this._error(ERROR_AUTH_ERROR, "no session token");
+    }
+    try {
+      // Anyone who needs the session token is going to send it to the server,
+      // so there's a chance we'll see an auth related error - so handle that
+      // here rather than requiring each caller to remember to.
+      let result = await func(data.sessionToken, state);
+      return state.resolve(result);
+    } catch (err) {
+      return this._handleTokenError(err);
+    }
+  },
+
+  get fxAccountsClient() {
+    if (!this._fxAccountsClient) {
+      this._fxAccountsClient = new lazy.FxAccountsClient();
+    }
+    return this._fxAccountsClient;
+  },
+
+  // The profile object used to fetch the actual user profile.
+  _profile: null,
+  get profile() {
+    if (!this._profile) {
+      let profileServerUrl = Services.urlFormatter.formatURLPref(
+        "identity.fxaccounts.remote.profile.uri"
+      );
+      this._profile = new lazy.FxAccountsProfile({
+        fxa: this,
+        profileServerUrl,
+      });
+    }
+    return this._profile;
+  },
+
+  _commands: null,
+  get commands() {
+    if (!this._commands) {
+      this._commands = new lazy.FxAccountsCommands(this);
+    }
+    return this._commands;
+  },
+
+  _device: null,
+  get device() {
+    if (!this._device) {
+      this._device = new lazy.FxAccountsDevice(this);
+    }
+    return this._device;
+  },
+
+  _telemetry: null,
+  get telemetry() {
+    if (!this._telemetry) {
+      this._telemetry = new lazy.FxAccountsTelemetry(this);
+    }
+    return this._telemetry;
+  },
+
+  // A hook-point for tests who may want a mocked AccountState or mocked storage.
+  newAccountState(credentials) {
+    let storage = new FxAccountsStorageManager();
+    storage.initialize(credentials);
+    return new AccountState(storage);
+  },
+
+  notifyDevices(deviceIds, excludedIds, payload, TTL) {
+    if (typeof deviceIds == "string") {
+      deviceIds = [deviceIds];
+    }
+    return this.withSessionToken(sessionToken => {
+      return this.fxAccountsClient.notifyDevices(
+        sessionToken,
+        deviceIds,
+        excludedIds,
+        payload,
+        TTL
+      );
+    });
+  },
+
+  /**
+   * Return the current time in milliseconds as an integer.  Allows tests to
+   * manipulate the date to simulate token expiration.
+   */
+  now() {
+    return this.fxAccountsClient.now();
+  },
+
+  /**
+   * Return clock offset in milliseconds, as reported by the fxAccountsClient.
+   * This can be overridden for testing.
+   *
+   * The offset is the number of milliseconds that must be added to the client
+   * clock to make it equal to the server clock.  For example, if the client is
+   * five minutes ahead of the server, the localtimeOffsetMsec will be -300000.
+   */
+  get localtimeOffsetMsec() {
+    return this.fxAccountsClient.localtimeOffsetMsec;
+  },
+
+  /**
+   * Ask the server whether the user's email has been verified
+   */
+  checkEmailStatus: function checkEmailStatus(sessionToken, options = {}) {
+    if (!sessionToken) {
+      return Promise.reject(
+        new Error("checkEmailStatus called without a session token")
+      );
+    }
+    return this.fxAccountsClient
+      .recoveryEmailStatus(sessionToken, options)
+      .catch(error => this._handleTokenError(error));
+  },
+
+  // set() makes sure that polling is happening, if necessary.
+  // get() does not wait for verification, and returns an object even if
+  // unverified. The caller of get() must check .verified .
+  // The "fxaccounts:onverified" event will fire only when the verified
+  // state goes from false to true, so callers must register their observer
+  // and then call get(). In particular, it will not fire when the account
+  // was found to be verified in a previous boot: if our stored state says
+  // the account is verified, the event will never fire. So callers must do:
+  //   register notification observer (go)
+  //   userdata = get()
+  //   if (userdata.verified()) {go()}
+
+  /**
+   * Set the current user signed in to Firefox Accounts.
+   *
+   * @param credentials
+   *        The credentials object obtained by logging in or creating
+   *        an account on the FxA server:
+   *        {
+   *          authAt: The time (seconds since epoch) that this record was
+   *                  authenticated
+   *          email: The users email address
+   *          keyFetchToken: a keyFetchToken which has not yet been used
+   *          sessionToken: Session for the FxA server
+   *          uid: The user's unique id
+   *          unwrapBKey: used to unwrap kB, derived locally from the
+   *                      password (not revealed to the FxA server)
+   *          verified: true/false
+   *        }
+   * @return Promise
+   *         The promise resolves to null when the data is saved
+   *         successfully and is rejected on error.
+   */
+  async setSignedInUser(credentials) {
+    if (!lazy.FXA_ENABLED) {
+      throw new Error("Cannot call setSignedInUser when FxA is disabled.");
+    }
+    lazy.Preferences.resetBranch(PREF_ACCOUNT_ROOT);
+    log.debug("setSignedInUser - aborting any existing flows");
+    const signedInUser = await this.currentAccountState.getUserAccountData();
+    if (signedInUser) {
+      await this._signOutServer(
+        signedInUser.sessionToken,
+        signedInUser.oauthTokens
+      );
+    }
+    await this.abortExistingFlow();
+    let currentAccountState = (this.currentAccountState = this.newAccountState(
+      Cu.cloneInto(credentials, {}) // Pass a clone of the credentials object.
+    ));
+    // This promise waits for storage, but not for verification.
+    // We're telling the caller that this is durable now (although is that
+    // really something we should commit to? Why not let the write happen in
+    // the background? Already does for updateAccountData ;)
+    await currentAccountState.promiseInitialized;
+    // Starting point for polling if new user
+    if (!this.isUserEmailVerified(credentials)) {
+      this.startVerifiedCheck(credentials);
+    }
+    await this.notifyObservers(ONLOGIN_NOTIFICATION);
+    await this.updateDeviceRegistration();
+    return currentAccountState.resolve();
+  },
+
+  /**
+   * Update account data for the currently signed in user.
+   *
+   * @param credentials
+   *        The credentials object containing the fields to be updated.
+   *        This object must contain the |uid| field and it must
+   *        match the currently signed in user.
+   */
+  updateUserAccountData(credentials) {
+    log.debug(
+      "updateUserAccountData called with fields",
+      Object.keys(credentials)
+    );
+    if (logPII) {
+      log.debug("updateUserAccountData called with data", credentials);
+    }
+    let currentAccountState = this.currentAccountState;
+    return currentAccountState.promiseInitialized.then(() => {
+      if (!credentials.uid) {
+        throw new Error("The specified credentials have no uid");
+      }
+      return currentAccountState.updateUserAccountData(credentials);
+    });
+  },
+
+  /*
+   * Reset state such that any previous flow is canceled.
+   */
+  abortExistingFlow() {
+    if (this.currentTimer) {
+      log.debug("Polling aborted; Another user signing in");
+      clearTimeout(this.currentTimer);
+      this.currentTimer = 0;
+    }
+    if (this._profile) {
+      this._profile.tearDown();
+      this._profile = null;
+    }
+    if (this._commands) {
+      this._commands = null;
+    }
+    if (this._device) {
+      this._device.reset();
+    }
+    // We "abort" the accountState and assume our caller is about to throw it
+    // away and replace it with a new one.
+    return this.currentAccountState.abort();
+  },
+
+  async checkVerificationStatus() {
+    log.trace("checkVerificationStatus");
+    let state = this.currentAccountState;
+    let data = await state.getUserAccountData();
+    if (!data) {
+      log.trace("checkVerificationStatus - no user data");
+      return null;
+    }
+
+    // Always check the verification status, even if the local state indicates
+    // we're already verified. If the user changed their password, the check
+    // will fail, and we'll enter the reauth state.
+    log.trace("checkVerificationStatus - forcing verification status check");
+    return this.startPollEmailStatus(state, data.sessionToken, "push");
+  },
+
+  _destroyOAuthToken(tokenData) {
+    return this.fxAccountsClient.oauthDestroy(
+      FX_OAUTH_CLIENT_ID,
+      tokenData.token
+    );
+  },
+
+  _destroyAllOAuthTokens(tokenInfos) {
+    if (!tokenInfos) {
+      return Promise.resolve();
+    }
+    // let's just destroy them all in parallel...
+    let promises = [];
+    for (let tokenInfo of Object.values(tokenInfos)) {
+      promises.push(this._destroyOAuthToken(tokenInfo));
+    }
+    return Promise.all(promises);
+  },
+
+  async signOut(localOnly) {
+    let sessionToken;
+    let tokensToRevoke;
+    const data = await this.currentAccountState.getUserAccountData();
+    // Save the sessionToken, tokens before resetting them in _signOutLocal().
+    if (data) {
+      sessionToken = data.sessionToken;
+      tokensToRevoke = data.oauthTokens;
+    }
+    await this.notifyObservers(ON_PRELOGOUT_NOTIFICATION);
+    await this._signOutLocal();
+    if (!localOnly) {
+      // Do this in the background so *any* slow request won't
+      // block the local sign out.
+      Services.tm.dispatchToMainThread(async () => {
+        await this._signOutServer(sessionToken, tokensToRevoke);
+        lazy.FxAccountsConfig.resetConfigURLs();
+        this.notifyObservers("testhelper-fxa-signout-complete");
+      });
+    } else {
+      // We want to do this either way -- but if we're signing out remotely we
+      // need to wait until we destroy the oauth tokens if we want that to succeed.
+      lazy.FxAccountsConfig.resetConfigURLs();
+    }
+    return this.notifyObservers(ONLOGOUT_NOTIFICATION);
+  },
+
+  async _signOutLocal() {
+    lazy.Preferences.resetBranch(PREF_ACCOUNT_ROOT);
+    await this.currentAccountState.signOut();
+    // this "aborts" this.currentAccountState but doesn't make a new one.
+    await this.abortExistingFlow();
+    this.currentAccountState = this.newAccountState();
+    return this.currentAccountState.promiseInitialized;
+  },
+
+  async _signOutServer(sessionToken, tokensToRevoke) {
+    log.debug("Unsubscribing from FxA push.");
+    try {
+      await this.fxaPushService.unsubscribe();
+    } catch (err) {
+      log.error("Could not unsubscribe from push.", err);
+    }
+    if (sessionToken) {
+      log.debug("Destroying session and device.");
+      try {
+        await this.fxAccountsClient.signOut(sessionToken, { service: "sync" });
+      } catch (err) {
+        log.error("Error during remote sign out of Firefox Accounts", err);
+      }
+    } else {
+      log.warn("Missing session token; skipping remote sign out");
+    }
+    log.debug("Destroying all OAuth tokens.");
+    try {
+      await this._destroyAllOAuthTokens(tokensToRevoke);
+    } catch (err) {
+      log.error("Error during destruction of oauth tokens during signout", err);
+    }
+  },
+
+  getUserAccountData(fieldNames = null) {
+    return this.currentAccountState.getUserAccountData(fieldNames);
+  },
+
+  isUserEmailVerified: function isUserEmailVerified(data) {
+    return !!(data && data.verified);
+  },
+
+  /**
+   * Setup for and if necessary do email verification polling.
+   */
+  loadAndPoll() {
+    let currentState = this.currentAccountState;
+    return currentState.getUserAccountData().then(data => {
+      if (data) {
+        if (!this.isUserEmailVerified(data)) {
+          this.startPollEmailStatus(
+            currentState,
+            data.sessionToken,
+            "browser-startup"
+          );
+        }
+      }
+      return data;
+    });
+  },
+
+  startVerifiedCheck(data) {
+    log.debug("startVerifiedCheck", data && data.verified);
+    if (logPII) {
+      log.debug("startVerifiedCheck with user data", data);
+    }
+
+    // Get us to the verified state. This returns a promise that will fire when
+    // verification is complete.
+
+    // The callers of startVerifiedCheck never consume a returned promise (ie,
+    // this is simply kicking off a background fetch) so we must add a rejection
+    // handler to avoid runtime warnings about the rejection not being handled.
+    this.whenVerified(data).catch(err =>
+      log.info("startVerifiedCheck promise was rejected: " + err)
+    );
+  },
+
+  whenVerified(data) {
+    let currentState = this.currentAccountState;
+    if (data.verified) {
+      log.debug("already verified");
+      return currentState.resolve(data);
+    }
+    if (!currentState.whenVerifiedDeferred) {
+      log.debug("whenVerified promise starts polling for verified email");
+      this.startPollEmailStatus(currentState, data.sessionToken, "start");
+    }
+    return currentState.whenVerifiedDeferred.promise.then(result =>
+      currentState.resolve(result)
+    );
+  },
+
+  async notifyObservers(topic, data) {
+    for (let f of this.observerPreloads) {
+      try {
+        await f();
+      } catch (O_o) {}
+    }
+    log.debug("Notifying observers of " + topic);
+    Services.obs.notifyObservers(null, topic, data);
+  },
+
+  startPollEmailStatus(currentState, sessionToken, why) {
+    log.debug("entering startPollEmailStatus: " + why);
+    // If we were already polling, stop and start again.  This could happen
+    // if the user requested the verification email to be resent while we
+    // were already polling for receipt of an earlier email.
+    if (this.currentTimer) {
+      log.debug(
+        "startPollEmailStatus starting while existing timer is running"
+      );
+      clearTimeout(this.currentTimer);
+      this.currentTimer = null;
+    }
+
+    this.pollStartDate = Date.now();
+    if (!currentState.whenVerifiedDeferred) {
+      currentState.whenVerifiedDeferred = PromiseUtils.defer();
+      // This deferred might not end up with any handlers (eg, if sync
+      // is yet to start up.)  This might cause "A promise chain failed to
+      // handle a rejection" messages, so add an error handler directly
+      // on the promise to log the error.
+      currentState.whenVerifiedDeferred.promise.then(
+        () => {
+          log.info("the user became verified");
+          // We are now ready for business. This should only be invoked once
+          // per setSignedInUser(), regardless of whether we've rebooted since
+          // setSignedInUser() was called.
+          this.notifyObservers(ONVERIFIED_NOTIFICATION);
+        },
+        err => {
+          log.info("the wait for user verification was stopped: " + err);
+        }
+      );
+    }
+    return this.pollEmailStatus(currentState, sessionToken, why);
+  },
+
+  // We return a promise for testing only. Other callers can ignore this,
+  // since verification polling continues in the background.
+  async pollEmailStatus(currentState, sessionToken, why) {
+    log.debug("entering pollEmailStatus: " + why);
+    let nextPollMs;
+    try {
+      const response = await this.checkEmailStatus(sessionToken, {
+        reason: why,
+      });
+      log.debug("checkEmailStatus -> " + JSON.stringify(response));
+      if (response && response.verified) {
+        await this.onPollEmailSuccess(currentState);
+        return;
+      }
+    } catch (error) {
+      if (error && error.code && error.code == 401) {
+        let error = new Error("Verification status check failed");
+        this._rejectWhenVerified(currentState, error);
+        return;
+      }
+      if (error && error.retryAfter) {
+        // If the server told us to back off, back off the requested amount.
+        nextPollMs = (error.retryAfter + 3) * 1000;
+        log.warn(
+          `the server rejected our email status check and told us to try again in ${nextPollMs}ms`
+        );
+      } else {
+        log.error(`checkEmailStatus failed to poll`, error);
+      }
+    }
+    if (why == "push") {
+      return;
+    }
+    let pollDuration = Date.now() - this.pollStartDate;
+    // Polling session expired.
+    if (pollDuration >= this.POLL_SESSION) {
+      if (currentState.whenVerifiedDeferred) {
+        let error = new Error("User email verification timed out.");
+        this._rejectWhenVerified(currentState, error);
+      }
+      log.debug("polling session exceeded, giving up");
+      return;
+    }
+    // Poll email status again after a short delay.
+    if (nextPollMs === undefined) {
+      let currentMinute = Math.ceil(pollDuration / 60000);
+      nextPollMs =
+        why == "start" &&
+        currentMinute < this.VERIFICATION_POLL_START_SLOWDOWN_THRESHOLD
+          ? this.VERIFICATION_POLL_TIMEOUT_INITIAL
+          : this.VERIFICATION_POLL_TIMEOUT_SUBSEQUENT;
+    }
+    this._scheduleNextPollEmailStatus(
+      currentState,
+      sessionToken,
+      nextPollMs,
+      why
+    );
+  },
+
+  // Easy-to-mock testable method
+  _scheduleNextPollEmailStatus(currentState, sessionToken, nextPollMs, why) {
+    log.debug("polling with timeout = " + nextPollMs);
+    this.currentTimer = setTimeout(() => {
+      this.pollEmailStatus(currentState, sessionToken, why);
+    }, nextPollMs);
+  },
+
+  async onPollEmailSuccess(currentState) {
+    try {
+      await currentState.updateUserAccountData({ verified: true });
+      const accountData = await currentState.getUserAccountData();
+      this._setLastUserPref(accountData.email);
+      // Now that the user is verified, we can proceed to fetch keys
+      if (currentState.whenVerifiedDeferred) {
+        currentState.whenVerifiedDeferred.resolve(accountData);
+        delete currentState.whenVerifiedDeferred;
+      }
+    } catch (e) {
+      log.error(e);
+    }
+  },
+
+  _rejectWhenVerified(currentState, error) {
+    currentState.whenVerifiedDeferred.reject(error);
+    delete currentState.whenVerifiedDeferred;
+  },
+
+  /**
+   * Does the actual fetch of an oauth token for getOAuthToken()
+   * using the account session token.
+   *
+   * It's split out into a separate method so that we can easily
+   * stash in-flight calls in a cache.
+   *
+   * @param {String} scopeString
+   * @param {Number} ttl
+   * @returns {Promise<string>}
+   * @private
+   */
+  async _doTokenFetchWithSessionToken(sessionToken, scopeString, ttl) {
+    const result = await this.fxAccountsClient.accessTokenWithSessionToken(
+      sessionToken,
+      FX_OAUTH_CLIENT_ID,
+      scopeString,
+      ttl
+    );
+    return result.access_token;
+  },
+
+  getOAuthToken(options = {}) {
+    log.debug("getOAuthToken enter");
+    let scope = options.scope;
+    if (typeof scope === "string") {
+      scope = [scope];
+    }
+
+    if (!scope || !scope.length) {
+      return Promise.reject(
+        this._error(
+          ERROR_INVALID_PARAMETER,
+          "Missing or invalid 'scope' option"
+        )
+      );
+    }
+
+    return this.withSessionToken(async (sessionToken, currentState) => {
+      // Early exit for a cached token.
+      let cached = currentState.getCachedToken(scope);
+      if (cached) {
+        log.debug("getOAuthToken returning a cached token");
+        return cached.token;
+      }
+
+      // Build the string we use in our "inflight" map and that we send to the
+      // server. Because it's used as a key in the map we sort the scopes.
+      let scopeString = scope.sort().join(" ");
+
+      // We keep a map of in-flight requests to avoid multiple promise-based
+      // consumers concurrently requesting the same token.
+      let maybeInFlight = currentState.inFlightTokenRequests.get(scopeString);
+      if (maybeInFlight) {
+        log.debug("getOAuthToken has an in-flight request for this scope");
+        return maybeInFlight;
+      }
+
+      // We need to start a new fetch and stick the promise in our in-flight map
+      // and remove it when it resolves.
+      let promise = this._doTokenFetchWithSessionToken(
+        sessionToken,
+        scopeString,
+        options.ttl
+      )
+        .then(token => {
+          // As a sanity check, ensure something else hasn't raced getting a token
+          // of the same scope. If something has we just make noise rather than
+          // taking any concrete action because it should never actually happen.
+          if (currentState.getCachedToken(scope)) {
+            log.error(`detected a race for oauth token with scope ${scope}`);
+          }
+          // If we got one, cache it.
+          if (token) {
+            let entry = { token };
+            currentState.setCachedToken(scope, entry);
+          }
+          return token;
+        })
+        .finally(() => {
+          // Remove ourself from the in-flight map. There's no need to check the
+          // result of .delete() to handle a signout race, because setCachedToken
+          // above will fail in that case and cause the entire call to fail.
+          currentState.inFlightTokenRequests.delete(scopeString);
+        });
+
+      currentState.inFlightTokenRequests.set(scopeString, promise);
+      return promise;
+    });
+  },
+
+  /**
+   * Remove an OAuth token from the token cache
+   * and makes a network request to FxA server to destroy the token.
+   *
+   * @param options
+   *        {
+   *          token: (string) A previously fetched token.
+   *        }
+   * @return Promise.<undefined> This function will always resolve, even if
+   *         an unknown token is passed.
+   */
+  removeCachedOAuthToken(options) {
+    if (!options.token || typeof options.token !== "string") {
+      throw this._error(
+        ERROR_INVALID_PARAMETER,
+        "Missing or invalid 'token' option"
+      );
+    }
+    return this.withCurrentAccountState(currentState => {
+      let existing = currentState.removeCachedToken(options.token);
+      if (existing) {
+        // background destroy.
+        this._destroyOAuthToken(existing).catch(err => {
+          log.warn("FxA failed to revoke a cached token", err);
+        });
+      }
+    });
+  },
+
+  async _getVerifiedAccountOrReject() {
+    let data = await this.currentAccountState.getUserAccountData();
+    if (!data) {
+      // No signed-in user
+      throw this._error(ERROR_NO_ACCOUNT);
+    }
+    if (!this.isUserEmailVerified(data)) {
+      // Signed-in user has not verified email
+      throw this._error(ERROR_UNVERIFIED_ACCOUNT);
+    }
+    return data;
+  },
+
+  // _handle* methods used by push, used when the account/device status is
+  // changed on a different device.
+  async _handleAccountDestroyed(uid) {
+    let state = this.currentAccountState;
+    const accountData = await state.getUserAccountData();
+    const localUid = accountData ? accountData.uid : null;
+    if (!localUid) {
+      log.info(
+        `Account destroyed push notification received, but we're already logged-out`
+      );
+      return null;
+    }
+    if (uid == localUid) {
+      const data = JSON.stringify({ isLocalDevice: true });
+      await this.notifyObservers(ON_DEVICE_DISCONNECTED_NOTIFICATION, data);
+      return this.signOut(true);
+    }
+    log.info(
+      `The destroyed account uid doesn't match with the local uid. ` +
+        `Local: ${localUid}, account uid destroyed: ${uid}`
+    );
+    return null;
+  },
+
+  async _handleDeviceDisconnection(deviceId) {
+    let state = this.currentAccountState;
+    const accountData = await state.getUserAccountData();
+    if (!accountData || !accountData.device) {
+      // Nothing we can do here.
+      return;
+    }
+    const localDeviceId = accountData.device.id;
+    const isLocalDevice = deviceId == localDeviceId;
+    if (isLocalDevice) {
+      this.signOut(true);
+    }
+    const data = JSON.stringify({ isLocalDevice });
+    await this.notifyObservers(ON_DEVICE_DISCONNECTED_NOTIFICATION, data);
+  },
+
+  _setLastUserPref(newEmail) {
+    Services.prefs.setStringPref(
+      PREF_LAST_FXA_USER,
+      CryptoUtils.sha256Base64(newEmail)
+    );
+  },
+
+  async _handleEmailUpdated(newEmail) {
+    this._setLastUserPref(newEmail);
+    await this.currentAccountState.updateUserAccountData({ email: newEmail });
+  },
+
+  /*
+   * Coerce an error into one of the general error cases:
+   *          NETWORK_ERROR
+   *          AUTH_ERROR
+   *          UNKNOWN_ERROR
+   *
+   * These errors will pass through:
+   *          INVALID_PARAMETER
+   *          NO_ACCOUNT
+   *          UNVERIFIED_ACCOUNT
+   */
+  _errorToErrorClass(aError) {
+    if (aError.errno) {
+      let error = SERVER_ERRNO_TO_ERROR[aError.errno];
+      return this._error(
+        ERROR_TO_GENERAL_ERROR_CLASS[error] || ERROR_UNKNOWN,
+        aError
+      );
+    } else if (
+      aError.message &&
+      (aError.message === "INVALID_PARAMETER" ||
+        aError.message === "NO_ACCOUNT" ||
+        aError.message === "UNVERIFIED_ACCOUNT" ||
+        aError.message === "AUTH_ERROR")
+    ) {
+      return aError;
+    }
+    return this._error(ERROR_UNKNOWN, aError);
+  },
+
+  _error(aError, aDetails) {
+    log.error("FxA rejecting with error ${aError}, details: ${aDetails}", {
+      aError,
+      aDetails,
+    });
+    let reason = new Error(aError);
+    if (aDetails) {
+      reason.details = aDetails;
+    }
+    return reason;
+  },
+
+  // Attempt to update the auth server with whatever device details are stored
+  // in the account data. Returns a promise that always resolves, never rejects.
+  // If the promise resolves to a value, that value is the device id.
+  updateDeviceRegistration() {
+    return this.device.updateDeviceRegistration();
+  },
+
+  /**
+   * Delete all the persisted credentials we store for FxA. After calling
+   * this, the user will be forced to re-authenticate to continue.
+   *
+   * @return Promise resolves when the user data has been persisted
+   */
+  dropCredentials(state) {
+    // Delete all fields except those required for the user to
+    // reauthenticate.
+    let updateData = {};
+    let clearField = field => {
+      if (!FXA_PWDMGR_REAUTH_ALLOWLIST.has(field)) {
+        updateData[field] = null;
+      }
+    };
+    FXA_PWDMGR_PLAINTEXT_FIELDS.forEach(clearField);
+    FXA_PWDMGR_SECURE_FIELDS.forEach(clearField);
+
+    return state.updateUserAccountData(updateData);
+  },
+
+  async checkAccountStatus(state) {
+    log.info("checking account status...");
+    let data = await state.getUserAccountData(["uid", "sessionToken"]);
+    if (!data) {
+      log.info("account status: no user");
+      return false;
+    }
+    // If we have a session token, then check if that remains valid - if this
+    // works we know the account must also be OK.
+    if (data.sessionToken) {
+      if (await this.fxAccountsClient.sessionStatus(data.sessionToken)) {
+        log.info("account status: ok");
+        return true;
+      }
+    }
+    let exists = await this.fxAccountsClient.accountStatus(data.uid);
+    if (!exists) {
+      // Delete all local account data. Since the account no longer
+      // exists, we can skip the remote calls.
+      log.info("account status: deleted");
+      await this._handleAccountDestroyed(data.uid);
+    } else {
+      // Note that we may already have been in a "needs reauth" state (ie, if
+      // this function was called when we already had no session token), but
+      // that's OK - re-notifying etc should cause no harm.
+      log.info("account status: needs reauthentication");
+      await this.dropCredentials(this.currentAccountState);
+      // Notify the account state has changed so the UI updates.
+      await this.notifyObservers(ON_ACCOUNT_STATE_CHANGE_NOTIFICATION);
+    }
+    return false;
+  },
+
+  async _handleTokenError(err) {
+    if (!err || err.code != 401 || err.errno != ERRNO_INVALID_AUTH_TOKEN) {
+      throw err;
+    }
+    log.warn("handling invalid token error", err);
+    // Note that we don't use `withCurrentAccountState` here as that will cause
+    // an error to be thrown if we sign out due to the account not existing.
+    let state = this.currentAccountState;
+    let ok = await this.checkAccountStatus(state);
+    if (ok) {
+      log.warn("invalid token error, but account state appears ok?");
+    }
+    // always re-throw the error.
+    throw err;
+  },
+};
+
+let fxAccountsSingleton = null;
+
+export function getFxAccountsSingleton() {
+  if (fxAccountsSingleton) {
+    return fxAccountsSingleton;
+  }
+
+  fxAccountsSingleton = new FxAccounts();
+
+  // XXX Bug 947061 - We need a strategy for resuming email verification after
+  // browser restart
+  fxAccountsSingleton._internal.loadAndPoll();
+
+  return fxAccountsSingleton;
+}
+
+// `AccountState` is exported for tests.