Add m-esr52 at 52.6.0

1 files changed, 983 insertions, 0 deletions

diff --git a/services/sync/modules/policies.js b/services/sync/modules/policies.js
new file mode 100644
index 000000000..a3933426d
--- /dev/null
+++ b/services/sync/modules/policies.js
@@ -0,0 +1,983 @@
+/* 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/. */
+
+this.EXPORTED_SYMBOLS = [
+  "ErrorHandler",
+  "SyncScheduler",
+];
+
+var {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
+
+Cu.import("resource://gre/modules/Log.jsm");
+Cu.import("resource://services-sync/constants.js");
+Cu.import("resource://services-sync/engines.js");
+Cu.import("resource://services-sync/util.js");
+Cu.import("resource://services-common/logmanager.js");
+Cu.import("resource://services-common/async.js");
+
+XPCOMUtils.defineLazyModuleGetter(this, "Status",
+                                  "resource://services-sync/status.js");
+XPCOMUtils.defineLazyModuleGetter(this, "AddonManager",
+                                  "resource://gre/modules/AddonManager.jsm");
+
+// Get the value for an interval that's stored in preferences. To save users
+// from themselves (and us from them!) the minimum time they can specify
+// is 60s.
+function getThrottledIntervalPreference(prefName) {
+  return Math.max(Svc.Prefs.get(prefName), 60) * 1000;
+}
+
+this.SyncScheduler = function SyncScheduler(service) {
+  this.service = service;
+  this.init();
+}
+SyncScheduler.prototype = {
+  _log: Log.repository.getLogger("Sync.SyncScheduler"),
+
+  _fatalLoginStatus: [LOGIN_FAILED_NO_USERNAME,
+                      LOGIN_FAILED_NO_PASSWORD,
+                      LOGIN_FAILED_NO_PASSPHRASE,
+                      LOGIN_FAILED_INVALID_PASSPHRASE,
+                      LOGIN_FAILED_LOGIN_REJECTED],
+
+  /**
+   * The nsITimer object that schedules the next sync. See scheduleNextSync().
+   */
+  syncTimer: null,
+
+  setDefaults: function setDefaults() {
+    this._log.trace("Setting SyncScheduler policy values to defaults.");
+
+    let service = Cc["@mozilla.org/weave/service;1"]
+                    .getService(Ci.nsISupports)
+                    .wrappedJSObject;
+
+    let part = service.fxAccountsEnabled ? "fxa" : "sync11";
+    let prefSDInterval = "scheduler." + part + ".singleDeviceInterval";
+    this.singleDeviceInterval = getThrottledIntervalPreference(prefSDInterval);
+
+    this.idleInterval         = getThrottledIntervalPreference("scheduler.idleInterval");
+    this.activeInterval       = getThrottledIntervalPreference("scheduler.activeInterval");
+    this.immediateInterval    = getThrottledIntervalPreference("scheduler.immediateInterval");
+    this.eolInterval          = getThrottledIntervalPreference("scheduler.eolInterval");
+
+    // A user is non-idle on startup by default.
+    this.idle = false;
+
+    this.hasIncomingItems = false;
+
+    this.clearSyncTriggers();
+  },
+
+  // nextSync is in milliseconds, but prefs can't hold that much
+  get nextSync() {
+    return Svc.Prefs.get("nextSync", 0) * 1000;
+  },
+  set nextSync(value) {
+    Svc.Prefs.set("nextSync", Math.floor(value / 1000));
+  },
+
+  get syncInterval() {
+    return Svc.Prefs.get("syncInterval", this.singleDeviceInterval);
+  },
+  set syncInterval(value) {
+    Svc.Prefs.set("syncInterval", value);
+  },
+
+  get syncThreshold() {
+    return Svc.Prefs.get("syncThreshold", SINGLE_USER_THRESHOLD);
+  },
+  set syncThreshold(value) {
+    Svc.Prefs.set("syncThreshold", value);
+  },
+
+  get globalScore() {
+    return Svc.Prefs.get("globalScore", 0);
+  },
+  set globalScore(value) {
+    Svc.Prefs.set("globalScore", value);
+  },
+
+  get numClients() {
+    return Svc.Prefs.get("numClients", 0);
+  },
+  set numClients(value) {
+    Svc.Prefs.set("numClients", value);
+  },
+
+  init: function init() {
+    this._log.level = Log.Level[Svc.Prefs.get("log.logger.service.main")];
+    this.setDefaults();
+    Svc.Obs.add("weave:engine:score:updated", this);
+    Svc.Obs.add("network:offline-status-changed", this);
+    Svc.Obs.add("weave:service:sync:start", this);
+    Svc.Obs.add("weave:service:sync:finish", this);
+    Svc.Obs.add("weave:engine:sync:finish", this);
+    Svc.Obs.add("weave:engine:sync:error", this);
+    Svc.Obs.add("weave:service:login:error", this);
+    Svc.Obs.add("weave:service:logout:finish", this);
+    Svc.Obs.add("weave:service:sync:error", this);
+    Svc.Obs.add("weave:service:backoff:interval", this);
+    Svc.Obs.add("weave:service:ready", this);
+    Svc.Obs.add("weave:engine:sync:applied", this);
+    Svc.Obs.add("weave:service:setup-complete", this);
+    Svc.Obs.add("weave:service:start-over", this);
+    Svc.Obs.add("FxA:hawk:backoff:interval", this);
+
+    if (Status.checkSetup() == STATUS_OK) {
+      Svc.Obs.add("wake_notification", this);
+      Svc.Idle.addIdleObserver(this, Svc.Prefs.get("scheduler.idleTime"));
+    }
+  },
+
+  observe: function observe(subject, topic, data) {
+    this._log.trace("Handling " + topic);
+    switch(topic) {
+      case "weave:engine:score:updated":
+        if (Status.login == LOGIN_SUCCEEDED) {
+          Utils.namedTimer(this.calculateScore, SCORE_UPDATE_DELAY, this,
+                           "_scoreTimer");
+        }
+        break;
+      case "network:offline-status-changed":
+        // Whether online or offline, we'll reschedule syncs
+        this._log.trace("Network offline status change: " + data);
+        this.checkSyncStatus();
+        break;
+      case "weave:service:sync:start":
+        // Clear out any potentially pending syncs now that we're syncing
+        this.clearSyncTriggers();
+
+        // reset backoff info, if the server tells us to continue backing off,
+        // we'll handle that later
+        Status.resetBackoff();
+
+        this.globalScore = 0;
+        break;
+      case "weave:service:sync:finish":
+        this.nextSync = 0;
+        this.adjustSyncInterval();
+
+        if (Status.service == SYNC_FAILED_PARTIAL && this.requiresBackoff) {
+          this.requiresBackoff = false;
+          this.handleSyncError();
+          return;
+        }
+
+        let sync_interval;
+        this._syncErrors = 0;
+        if (Status.sync == NO_SYNC_NODE_FOUND) {
+          this._log.trace("Scheduling a sync at interval NO_SYNC_NODE_FOUND.");
+          sync_interval = NO_SYNC_NODE_INTERVAL;
+        }
+        this.scheduleNextSync(sync_interval);
+        break;
+      case "weave:engine:sync:finish":
+        if (data == "clients") {
+          // Update the client mode because it might change what we sync.
+          this.updateClientMode();
+        }
+        break;
+      case "weave:engine:sync:error":
+        // `subject` is the exception thrown by an engine's sync() method.
+        let exception = subject;
+        if (exception.status >= 500 && exception.status <= 504) {
+          this.requiresBackoff = true;
+        }
+        break;
+      case "weave:service:login:error":
+        this.clearSyncTriggers();
+
+        if (Status.login == MASTER_PASSWORD_LOCKED) {
+          // Try again later, just as if we threw an error... only without the
+          // error count.
+          this._log.debug("Couldn't log in: master password is locked.");
+          this._log.trace("Scheduling a sync at MASTER_PASSWORD_LOCKED_RETRY_INTERVAL");
+          this.scheduleAtInterval(MASTER_PASSWORD_LOCKED_RETRY_INTERVAL);
+        } else if (this._fatalLoginStatus.indexOf(Status.login) == -1) {
+          // Not a fatal login error, just an intermittent network or server
+          // issue. Keep on syncin'.
+          this.checkSyncStatus();
+        }
+        break;
+      case "weave:service:logout:finish":
+        // Start or cancel the sync timer depending on if
+        // logged in or logged out
+        this.checkSyncStatus();
+        break;
+      case "weave:service:sync:error":
+        // There may be multiple clients but if the sync fails, client mode
+        // should still be updated so that the next sync has a correct interval.
+        this.updateClientMode();
+        this.adjustSyncInterval();
+        this.nextSync = 0;
+        this.handleSyncError();
+        break;
+      case "FxA:hawk:backoff:interval":
+      case "weave:service:backoff:interval":
+        let requested_interval = subject * 1000;
+        this._log.debug("Got backoff notification: " + requested_interval + "ms");
+        // Leave up to 25% more time for the back off.
+        let interval = requested_interval * (1 + Math.random() * 0.25);
+        Status.backoffInterval = interval;
+        Status.minimumNextSync = Date.now() + requested_interval;
+        this._log.debug("Fuzzed minimum next sync: " + Status.minimumNextSync);
+        break;
+      case "weave:service:ready":
+        // Applications can specify this preference if they want autoconnect
+        // to happen after a fixed delay.
+        let delay = Svc.Prefs.get("autoconnectDelay");
+        if (delay) {
+          this.delayedAutoConnect(delay);
+        }
+        break;
+      case "weave:engine:sync:applied":
+        let numItems = subject.succeeded;
+        this._log.trace("Engine " + data + " successfully applied " + numItems +
+                        " items.");
+        if (numItems) {
+          this.hasIncomingItems = true;
+        }
+        break;
+      case "weave:service:setup-complete":
+         Services.prefs.savePrefFile(null);
+         Svc.Idle.addIdleObserver(this, Svc.Prefs.get("scheduler.idleTime"));
+         Svc.Obs.add("wake_notification", this);
+         break;
+      case "weave:service:start-over":
+         this.setDefaults();
+         try {
+           Svc.Idle.removeIdleObserver(this, Svc.Prefs.get("scheduler.idleTime"));
+         } catch (ex) {
+           if (ex.result != Cr.NS_ERROR_FAILURE) {
+             throw ex;
+           }
+           // In all likelihood we didn't have an idle observer registered yet.
+           // It's all good.
+         }
+         break;
+      case "idle":
+        this._log.trace("We're idle.");
+        this.idle = true;
+        // Adjust the interval for future syncs. This won't actually have any
+        // effect until the next pending sync (which will happen soon since we
+        // were just active.)
+        this.adjustSyncInterval();
+        break;
+      case "active":
+        this._log.trace("Received notification that we're back from idle.");
+        this.idle = false;
+        Utils.namedTimer(function onBack() {
+          if (this.idle) {
+            this._log.trace("... and we're idle again. " +
+                            "Ignoring spurious back notification.");
+            return;
+          }
+
+          this._log.trace("Genuine return from idle. Syncing.");
+          // Trigger a sync if we have multiple clients.
+          if (this.numClients > 1) {
+            this.scheduleNextSync(0);
+          }
+        }, IDLE_OBSERVER_BACK_DELAY, this, "idleDebouncerTimer");
+        break;
+      case "wake_notification":
+        this._log.debug("Woke from sleep.");
+        Utils.nextTick(() => {
+          // Trigger a sync if we have multiple clients. We give it 5 seconds
+          // incase the network is still in the process of coming back up.
+          if (this.numClients > 1) {
+            this._log.debug("More than 1 client. Will sync in 5s.");
+            this.scheduleNextSync(5000);
+          }
+        });
+        break;
+    }
+  },
+
+  adjustSyncInterval: function adjustSyncInterval() {
+    if (Status.eol) {
+      this._log.debug("Server status is EOL; using eolInterval.");
+      this.syncInterval = this.eolInterval;
+      return;
+    }
+
+    if (this.numClients <= 1) {
+      this._log.trace("Adjusting syncInterval to singleDeviceInterval.");
+      this.syncInterval = this.singleDeviceInterval;
+      return;
+    }
+
+    // Only MULTI_DEVICE clients will enter this if statement
+    // since SINGLE_USER clients will be handled above.
+    if (this.idle) {
+      this._log.trace("Adjusting syncInterval to idleInterval.");
+      this.syncInterval = this.idleInterval;
+      return;
+    }
+
+    if (this.hasIncomingItems) {
+      this._log.trace("Adjusting syncInterval to immediateInterval.");
+      this.hasIncomingItems = false;
+      this.syncInterval = this.immediateInterval;
+    } else {
+      this._log.trace("Adjusting syncInterval to activeInterval.");
+      this.syncInterval = this.activeInterval;
+    }
+  },
+
+  calculateScore: function calculateScore() {
+    let engines = [this.service.clientsEngine].concat(this.service.engineManager.getEnabled());
+    for (let i = 0;i < engines.length;i++) {
+      this._log.trace(engines[i].name + ": score: " + engines[i].score);
+      this.globalScore += engines[i].score;
+      engines[i]._tracker.resetScore();
+    }
+
+    this._log.trace("Global score updated: " + this.globalScore);
+    this.checkSyncStatus();
+  },
+
+  /**
+   * Process the locally stored clients list to figure out what mode to be in
+   */
+  updateClientMode: function updateClientMode() {
+    // Nothing to do if it's the same amount
+    let numClients = this.service.clientsEngine.stats.numClients;
+    if (this.numClients == numClients)
+      return;
+
+    this._log.debug("Client count: " + this.numClients + " -> " + numClients);
+    this.numClients = numClients;
+
+    if (numClients <= 1) {
+      this._log.trace("Adjusting syncThreshold to SINGLE_USER_THRESHOLD");
+      this.syncThreshold = SINGLE_USER_THRESHOLD;
+    } else {
+      this._log.trace("Adjusting syncThreshold to MULTI_DEVICE_THRESHOLD");
+      this.syncThreshold = MULTI_DEVICE_THRESHOLD;
+    }
+    this.adjustSyncInterval();
+  },
+
+  /**
+   * Check if we should be syncing and schedule the next sync, if it's not scheduled
+   */
+  checkSyncStatus: function checkSyncStatus() {
+    // Should we be syncing now, if not, cancel any sync timers and return
+    // if we're in backoff, we'll schedule the next sync.
+    let ignore = [kSyncBackoffNotMet, kSyncMasterPasswordLocked];
+    let skip = this.service._checkSync(ignore);
+    this._log.trace("_checkSync returned \"" + skip + "\".");
+    if (skip) {
+      this.clearSyncTriggers();
+      return;
+    }
+
+    // Only set the wait time to 0 if we need to sync right away
+    let wait;
+    if (this.globalScore > this.syncThreshold) {
+      this._log.debug("Global Score threshold hit, triggering sync.");
+      wait = 0;
+    }
+    this.scheduleNextSync(wait);
+  },
+
+  /**
+   * Call sync() if Master Password is not locked.
+   *
+   * Otherwise, reschedule a sync for later.
+   */
+  syncIfMPUnlocked: function syncIfMPUnlocked() {
+    // No point if we got kicked out by the master password dialog.
+    if (Status.login == MASTER_PASSWORD_LOCKED &&
+        Utils.mpLocked()) {
+      this._log.debug("Not initiating sync: Login status is " + Status.login);
+
+      // If we're not syncing now, we need to schedule the next one.
+      this._log.trace("Scheduling a sync at MASTER_PASSWORD_LOCKED_RETRY_INTERVAL");
+      this.scheduleAtInterval(MASTER_PASSWORD_LOCKED_RETRY_INTERVAL);
+      return;
+    }
+
+    Utils.nextTick(this.service.sync, this.service);
+  },
+
+  /**
+   * Set a timer for the next sync
+   */
+  scheduleNextSync: function scheduleNextSync(interval) {
+    // If no interval was specified, use the current sync interval.
+    if (interval == null) {
+      interval = this.syncInterval;
+    }
+
+    // Ensure the interval is set to no less than the backoff.
+    if (Status.backoffInterval && interval < Status.backoffInterval) {
+      this._log.trace("Requested interval " + interval +
+                      " ms is smaller than the backoff interval. " +
+                      "Using backoff interval " +
+                      Status.backoffInterval + " ms instead.");
+      interval = Status.backoffInterval;
+    }
+
+    if (this.nextSync != 0) {
+      // There's already a sync scheduled. Don't reschedule if there's already
+      // a timer scheduled for sooner than requested.
+      let currentInterval = this.nextSync - Date.now();
+      this._log.trace("There's already a sync scheduled in " +
+                      currentInterval + " ms.");
+      if (currentInterval < interval && this.syncTimer) {
+        this._log.trace("Ignoring scheduling request for next sync in " +
+                        interval + " ms.");
+        return;
+      }
+    }
+
+    // Start the sync right away if we're already late.
+    if (interval <= 0) {
+      this._log.trace("Requested sync should happen right away.");
+      this.syncIfMPUnlocked();
+      return;
+    }
+
+    this._log.debug("Next sync in " + interval + " ms.");
+    Utils.namedTimer(this.syncIfMPUnlocked, interval, this, "syncTimer");
+
+    // Save the next sync time in-case sync is disabled (logout/offline/etc.)
+    this.nextSync = Date.now() + interval;
+  },
+
+
+  /**
+   * Incorporates the backoff/retry logic used in error handling and elective
+   * non-syncing.
+   */
+  scheduleAtInterval: function scheduleAtInterval(minimumInterval) {
+    let interval = Utils.calculateBackoff(this._syncErrors,
+                                          MINIMUM_BACKOFF_INTERVAL,
+                                          Status.backoffInterval);
+    if (minimumInterval) {
+      interval = Math.max(minimumInterval, interval);
+    }
+
+    this._log.debug("Starting client-initiated backoff. Next sync in " +
+                    interval + " ms.");
+    this.scheduleNextSync(interval);
+  },
+
+ /**
+  * Automatically start syncing after the given delay (in seconds).
+  *
+  * Applications can define the `services.sync.autoconnectDelay` preference
+  * to have this called automatically during start-up with the pref value as
+  * the argument. Alternatively, they can call it themselves to control when
+  * Sync should first start to sync.
+  */
+  delayedAutoConnect: function delayedAutoConnect(delay) {
+    if (this.service._checkSetup() == STATUS_OK) {
+      Utils.namedTimer(this.autoConnect, delay * 1000, this, "_autoTimer");
+    }
+  },
+
+  autoConnect: function autoConnect() {
+    if (this.service._checkSetup() == STATUS_OK && !this.service._checkSync()) {
+      // Schedule a sync based on when a previous sync was scheduled.
+      // scheduleNextSync() will do the right thing if that time lies in
+      // the past.
+      this.scheduleNextSync(this.nextSync - Date.now());
+    }
+
+    // Once autoConnect is called we no longer need _autoTimer.
+    if (this._autoTimer) {
+      this._autoTimer.clear();
+    }
+  },
+
+  _syncErrors: 0,
+  /**
+   * Deal with sync errors appropriately
+   */
+  handleSyncError: function handleSyncError() {
+    this._log.trace("In handleSyncError. Error count: " + this._syncErrors);
+    this._syncErrors++;
+
+    // Do nothing on the first couple of failures, if we're not in
+    // backoff due to 5xx errors.
+    if (!Status.enforceBackoff) {
+      if (this._syncErrors < MAX_ERROR_COUNT_BEFORE_BACKOFF) {
+        this.scheduleNextSync();
+        return;
+      }
+      this._log.debug("Sync error count has exceeded " +
+                      MAX_ERROR_COUNT_BEFORE_BACKOFF + "; enforcing backoff.");
+      Status.enforceBackoff = true;
+    }
+
+    this.scheduleAtInterval();
+  },
+
+
+  /**
+   * Remove any timers/observers that might trigger a sync
+   */
+  clearSyncTriggers: function clearSyncTriggers() {
+    this._log.debug("Clearing sync triggers and the global score.");
+    this.globalScore = this.nextSync = 0;
+
+    // Clear out any scheduled syncs
+    if (this.syncTimer)
+      this.syncTimer.clear();
+  },
+
+};
+
+this.ErrorHandler = function ErrorHandler(service) {
+  this.service = service;
+  this.init();
+}
+ErrorHandler.prototype = {
+  MINIMUM_ALERT_INTERVAL_MSEC: 604800000,   // One week.
+
+  /**
+   * Flag that turns on error reporting for all errors, incl. network errors.
+   */
+  dontIgnoreErrors: false,
+
+  /**
+   * Flag that indicates if we have already reported a prolonged failure.
+   * Once set, we don't report it again, meaning this error is only reported
+   * one per run.
+   */
+  didReportProlongedError: false,
+
+  init: function init() {
+    Svc.Obs.add("weave:engine:sync:applied", this);
+    Svc.Obs.add("weave:engine:sync:error", this);
+    Svc.Obs.add("weave:service:login:error", this);
+    Svc.Obs.add("weave:service:sync:error", this);
+    Svc.Obs.add("weave:service:sync:finish", this);
+
+    this.initLogs();
+  },
+
+  initLogs: function initLogs() {
+    this._log = Log.repository.getLogger("Sync.ErrorHandler");
+    this._log.level = Log.Level[Svc.Prefs.get("log.logger.service.main")];
+
+    let root = Log.repository.getLogger("Sync");
+    root.level = Log.Level[Svc.Prefs.get("log.rootLogger")];
+
+    let logs = ["Sync", "FirefoxAccounts", "Hawk", "Common.TokenServerClient",
+                "Sync.SyncMigration", "browserwindow.syncui",
+                "Services.Common.RESTRequest", "Services.Common.RESTRequest",
+                "BookmarkSyncUtils"
+               ];
+
+    this._logManager = new LogManager(Svc.Prefs, logs, "sync");
+  },
+
+  observe: function observe(subject, topic, data) {
+    this._log.trace("Handling " + topic);
+    switch(topic) {
+      case "weave:engine:sync:applied":
+        if (subject.newFailed) {
+          // An engine isn't able to apply one or more incoming records.
+          // We don't fail hard on this, but it usually indicates a bug,
+          // so for now treat it as sync error (c.f. Service._syncEngine())
+          Status.engines = [data, ENGINE_APPLY_FAIL];
+          this._log.debug(data + " failed to apply some records.");
+        }
+        break;
+      case "weave:engine:sync:error": {
+        let exception = subject;  // exception thrown by engine's sync() method
+        let engine_name = data;   // engine name that threw the exception
+
+        this.checkServerError(exception);
+
+        Status.engines = [engine_name, exception.failureCode || ENGINE_UNKNOWN_FAIL];
+        if (Async.isShutdownException(exception)) {
+          this._log.debug(engine_name + " was interrupted due to the application shutting down");
+        } else {
+          this._log.debug(engine_name + " failed", exception);
+          Services.telemetry.getKeyedHistogramById("WEAVE_ENGINE_SYNC_ERRORS")
+                            .add(engine_name);
+        }
+        break;
+      }
+      case "weave:service:login:error":
+        this._log.error("Sync encountered a login error");
+        this.resetFileLog();
+
+        if (this.shouldReportError()) {
+          this.notifyOnNextTick("weave:ui:login:error");
+        } else {
+          this.notifyOnNextTick("weave:ui:clear-error");
+        }
+
+        this.dontIgnoreErrors = false;
+        break;
+      case "weave:service:sync:error": {
+        if (Status.sync == CREDENTIALS_CHANGED) {
+          this.service.logout();
+        }
+
+        let exception = subject;
+        if (Async.isShutdownException(exception)) {
+          // If we are shutting down we just log the fact, attempt to flush
+          // the log file and get out of here!
+          this._log.error("Sync was interrupted due to the application shutting down");
+          this.resetFileLog();
+          break;
+        }
+
+        // Not a shutdown related exception...
+        this._log.error("Sync encountered an error", exception);
+        this.resetFileLog();
+
+        if (this.shouldReportError()) {
+          this.notifyOnNextTick("weave:ui:sync:error");
+        } else {
+          this.notifyOnNextTick("weave:ui:sync:finish");
+        }
+
+        this.dontIgnoreErrors = false;
+        break;
+      }
+      case "weave:service:sync:finish":
+        this._log.trace("Status.service is " + Status.service);
+
+        // Check both of these status codes: in the event of a failure in one
+        // engine, Status.service will be SYNC_FAILED_PARTIAL despite
+        // Status.sync being SYNC_SUCCEEDED.
+        // *facepalm*
+        if (Status.sync    == SYNC_SUCCEEDED &&
+            Status.service == STATUS_OK) {
+          // Great. Let's clear our mid-sync 401 note.
+          this._log.trace("Clearing lastSyncReassigned.");
+          Svc.Prefs.reset("lastSyncReassigned");
+        }
+
+        if (Status.service == SYNC_FAILED_PARTIAL) {
+          this._log.error("Some engines did not sync correctly.");
+          this.resetFileLog();
+
+          if (this.shouldReportError()) {
+            this.dontIgnoreErrors = false;
+            this.notifyOnNextTick("weave:ui:sync:error");
+            break;
+          }
+        } else {
+          this.resetFileLog();
+        }
+        this.dontIgnoreErrors = false;
+        this.notifyOnNextTick("weave:ui:sync:finish");
+        break;
+    }
+  },
+
+  notifyOnNextTick: function notifyOnNextTick(topic) {
+    Utils.nextTick(function() {
+      this._log.trace("Notifying " + topic +
+                      ". Status.login is " + Status.login +
+                      ". Status.sync is " + Status.sync);
+      Svc.Obs.notify(topic);
+    }, this);
+  },
+
+  /**
+   * Trigger a sync and don't muffle any errors, particularly network errors.
+   */
+  syncAndReportErrors: function syncAndReportErrors() {
+    this._log.debug("Beginning user-triggered sync.");
+
+    this.dontIgnoreErrors = true;
+    Utils.nextTick(this.service.sync, this.service);
+  },
+
+  _dumpAddons: function _dumpAddons() {
+    // Just dump the items that sync may be concerned with. Specifically,
+    // active extensions that are not hidden.
+    let addonPromise = new Promise(resolve => {
+      try {
+        AddonManager.getAddonsByTypes(["extension"], resolve);
+      } catch (e) {
+        this._log.warn("Failed to dump addons", e)
+        resolve([])
+      }
+    });
+
+    return addonPromise.then(addons => {
+      let relevantAddons = addons.filter(x => x.isActive && !x.hidden);
+      this._log.debug("Addons installed", relevantAddons.length);
+      for (let addon of relevantAddons) {
+        this._log.debug(" - ${name}, version ${version}, id ${id}", addon);
+      }
+    });
+  },
+
+  /**
+   * Generate a log file for the sync that just completed
+   * and refresh the input & output streams.
+   */
+  resetFileLog: function resetFileLog() {
+    let onComplete = logType => {
+      Svc.Obs.notify("weave:service:reset-file-log");
+      this._log.trace("Notified: " + Date.now());
+      if (logType == this._logManager.ERROR_LOG_WRITTEN) {
+        Cu.reportError("Sync encountered an error - see about:sync-log for the log file.");
+      }
+    };
+
+    // If we're writing an error log, dump extensions that may be causing problems.
+    let beforeResetLog;
+    if (this._logManager.sawError) {
+      beforeResetLog = this._dumpAddons();
+    } else {
+      beforeResetLog = Promise.resolve();
+    }
+    // Note we do not return the promise here - the caller doesn't need to wait
+    // for this to complete.
+    beforeResetLog
+      .then(() => this._logManager.resetFileLog())
+      .then(onComplete, onComplete);
+  },
+
+  /**
+   * Translates server error codes to meaningful strings.
+   *
+   * @param code
+   *        server error code as an integer
+   */
+  errorStr: function errorStr(code) {
+    switch (code.toString()) {
+    case "1":
+      return "illegal-method";
+    case "2":
+      return "invalid-captcha";
+    case "3":
+      return "invalid-username";
+    case "4":
+      return "cannot-overwrite-resource";
+    case "5":
+      return "userid-mismatch";
+    case "6":
+      return "json-parse-failure";
+    case "7":
+      return "invalid-password";
+    case "8":
+      return "invalid-record";
+    case "9":
+      return "weak-password";
+    default:
+      return "generic-server-error";
+    }
+  },
+
+  // A function to indicate if Sync errors should be "reported" - which in this
+  // context really means "should be notify observers of an error" - but note
+  // that since bug 1180587, no one is going to surface an error to the user.
+  shouldReportError: function shouldReportError() {
+    if (Status.login == MASTER_PASSWORD_LOCKED) {
+      this._log.trace("shouldReportError: false (master password locked).");
+      return false;
+    }
+
+    if (this.dontIgnoreErrors) {
+      return true;
+    }
+
+    if (Status.login == LOGIN_FAILED_LOGIN_REJECTED) {
+      // An explicit LOGIN_REJECTED state is always reported (bug 1081158)
+      this._log.trace("shouldReportError: true (login was rejected)");
+      return true;
+    }
+
+    let lastSync = Svc.Prefs.get("lastSync");
+    if (lastSync && ((Date.now() - Date.parse(lastSync)) >
+        Svc.Prefs.get("errorhandler.networkFailureReportTimeout") * 1000)) {
+      Status.sync = PROLONGED_SYNC_FAILURE;
+      if (this.didReportProlongedError) {
+        this._log.trace("shouldReportError: false (prolonged sync failure, but" +
+                        " we've already reported it).");
+        return false;
+      }
+      this._log.trace("shouldReportError: true (first prolonged sync failure).");
+      this.didReportProlongedError = true;
+      return true;
+    }
+
+    // We got a 401 mid-sync. Wait for the next sync before actually handling
+    // an error. This assumes that we'll get a 401 again on a login fetch in
+    // order to report the error.
+    if (!this.service.clusterURL) {
+      this._log.trace("shouldReportError: false (no cluster URL; " +
+                      "possible node reassignment).");
+      return false;
+    }
+
+
+    let result = ([Status.login, Status.sync].indexOf(SERVER_MAINTENANCE) == -1 &&
+                  [Status.login, Status.sync].indexOf(LOGIN_FAILED_NETWORK_ERROR) == -1);
+    this._log.trace("shouldReportError: ${result} due to login=${login}, sync=${sync}",
+                    {result, login: Status.login, sync: Status.sync});
+    return result;
+  },
+
+  get currentAlertMode() {
+    return Svc.Prefs.get("errorhandler.alert.mode");
+  },
+
+  set currentAlertMode(str) {
+    return Svc.Prefs.set("errorhandler.alert.mode", str);
+  },
+
+  get earliestNextAlert() {
+    return Svc.Prefs.get("errorhandler.alert.earliestNext", 0) * 1000;
+  },
+
+  set earliestNextAlert(msec) {
+    return Svc.Prefs.set("errorhandler.alert.earliestNext", msec / 1000);
+  },
+
+  clearServerAlerts: function () {
+    // If we have any outstanding alerts, apparently they're no longer relevant.
+    Svc.Prefs.resetBranch("errorhandler.alert");
+  },
+
+  /**
+   * X-Weave-Alert headers can include a JSON object:
+   *
+   *   {
+   *    "code":    // One of "hard-eol", "soft-eol".
+   *    "url":     // For "Learn more" link.
+   *    "message": // Logged in Sync logs.
+   *   }
+   */
+  handleServerAlert: function (xwa) {
+    if (!xwa.code) {
+      this._log.warn("Got structured X-Weave-Alert, but no alert code.");
+      return;
+    }
+
+    switch (xwa.code) {
+      // Gently and occasionally notify the user that this service will be
+      // shutting down.
+      case "soft-eol":
+        // Fall through.
+
+      // Tell the user that this service has shut down, and drop our syncing
+      // frequency dramatically.
+      case "hard-eol":
+        // Note that both of these alerts should be subservient to future "sign
+        // in with your Firefox Account" storage alerts.
+        if ((this.currentAlertMode != xwa.code) ||
+            (this.earliestNextAlert < Date.now())) {
+          Utils.nextTick(function() {
+            Svc.Obs.notify("weave:eol", xwa);
+          }, this);
+          this._log.error("X-Weave-Alert: " + xwa.code + ": " + xwa.message);
+          this.earliestNextAlert = Date.now() + this.MINIMUM_ALERT_INTERVAL_MSEC;
+          this.currentAlertMode = xwa.code;
+        }
+        break;
+      default:
+        this._log.debug("Got unexpected X-Weave-Alert code: " + xwa.code);
+    }
+  },
+
+  /**
+   * Handle HTTP response results or exceptions and set the appropriate
+   * Status.* bits.
+   *
+   * This method also looks for "side-channel" warnings.
+   */
+  checkServerError: function (resp) {
+    switch (resp.status) {
+      case 200:
+      case 404:
+      case 513:
+        let xwa = resp.headers['x-weave-alert'];
+
+        // Only process machine-readable alerts.
+        if (!xwa || !xwa.startsWith("{")) {
+          this.clearServerAlerts();
+          return;
+        }
+
+        try {
+          xwa = JSON.parse(xwa);
+        } catch (ex) {
+          this._log.warn("Malformed X-Weave-Alert from server: " + xwa);
+          return;
+        }
+
+        this.handleServerAlert(xwa);
+        break;
+
+      case 400:
+        if (resp == RESPONSE_OVER_QUOTA) {
+          Status.sync = OVER_QUOTA;
+        }
+        break;
+
+      case 401:
+        this.service.logout();
+        this._log.info("Got 401 response; resetting clusterURL.");
+        this.service.clusterURL = null;
+
+        let delay = 0;
+        if (Svc.Prefs.get("lastSyncReassigned")) {
+          // We got a 401 in the middle of the previous sync, and we just got
+          // another. Login must have succeeded in order for us to get here, so
+          // the password should be correct.
+          // This is likely to be an intermittent server issue, so back off and
+          // give it time to recover.
+          this._log.warn("Last sync also failed for 401. Delaying next sync.");
+          delay = MINIMUM_BACKOFF_INTERVAL;
+        } else {
+          this._log.debug("New mid-sync 401 failure. Making a note.");
+          Svc.Prefs.set("lastSyncReassigned", true);
+        }
+        this._log.info("Attempting to schedule another sync.");
+        this.service.scheduler.scheduleNextSync(delay);
+        break;
+
+      case 500:
+      case 502:
+      case 503:
+      case 504:
+        Status.enforceBackoff = true;
+        if (resp.status == 503 && resp.headers["retry-after"]) {
+          let retryAfter = resp.headers["retry-after"];
+          this._log.debug("Got Retry-After: " + retryAfter);
+          if (this.service.isLoggedIn) {
+            Status.sync = SERVER_MAINTENANCE;
+          } else {
+            Status.login = SERVER_MAINTENANCE;
+          }
+          Svc.Obs.notify("weave:service:backoff:interval",
+                         parseInt(retryAfter, 10));
+        }
+        break;
+    }
+
+    switch (resp.result) {
+      case Cr.NS_ERROR_UNKNOWN_HOST:
+      case Cr.NS_ERROR_CONNECTION_REFUSED:
+      case Cr.NS_ERROR_NET_TIMEOUT:
+      case Cr.NS_ERROR_NET_RESET:
+      case Cr.NS_ERROR_NET_INTERRUPT:
+      case Cr.NS_ERROR_PROXY_CONNECTION_REFUSED:
+        // The constant says it's about login, but in fact it just
+        // indicates general network error.
+        if (this.service.isLoggedIn) {
+          Status.sync = LOGIN_FAILED_NETWORK_ERROR;
+        } else {
+          Status.login = LOGIN_FAILED_NETWORK_ERROR;
+        }
+        break;
+    }
+  },
+};