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+/* 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 file contains middleware to reconcile state of AddonManager for
+ * purposes of tracking events for Sync. The content in this file exists
+ * because AddonManager does not have a getChangesSinceX() API and adding
+ * that functionality properly was deemed too time-consuming at the time
+ * add-on sync was originally written. If/when AddonManager adds this API,
+ * this file can go away and the add-ons engine can be rewritten to use it.
+ *
+ * It was decided to have this tracking functionality exist in a separate
+ * standalone file so it could be more easily understood, tested, and
+ * hopefully ported.
+ */
+
+import { Log } from "resource://gre/modules/Log.sys.mjs";
+
+import { Svc, Utils } from "resource://services-sync/util.sys.mjs";
+
+import { AddonManager } from "resource://gre/modules/AddonManager.sys.mjs";
+
+const DEFAULT_STATE_FILE = "addonsreconciler";
+
+export var CHANGE_INSTALLED = 1;
+export var CHANGE_UNINSTALLED = 2;
+export var CHANGE_ENABLED = 3;
+export var CHANGE_DISABLED = 4;
+
+/**
+ * Maintains state of add-ons.
+ *
+ * State is maintained in 2 data structures, an object mapping add-on IDs
+ * to metadata and an array of changes over time. The object mapping can be
+ * thought of as a minimal copy of data from AddonManager which is needed for
+ * Sync. The array is effectively a log of changes over time.
+ *
+ * The data structures are persisted to disk by serializing to a JSON file in
+ * the current profile. The data structures are updated by 2 mechanisms. First,
+ * they can be refreshed from the global state of the AddonManager. This is a
+ * sure-fire way of ensuring the reconciler is up to date. Second, the
+ * reconciler adds itself as an AddonManager listener. When it receives change
+ * notifications, it updates its internal state incrementally.
+ *
+ * The internal state is persisted to a JSON file in the profile directory.
+ *
+ * An instance of this is bound to an AddonsEngine instance. In reality, it
+ * likely exists as a singleton. To AddonsEngine, it functions as a store and
+ * an entity which emits events for tracking.
+ *
+ * The usage pattern for instances of this class is:
+ *
+ * let reconciler = new AddonsReconciler(...);
+ * await reconciler.ensureStateLoaded();
+ *
+ * // At this point, your instance should be ready to use.
+ *
+ * When you are finished with the instance, please call:
+ *
+ * reconciler.stopListening();
+ * await reconciler.saveState(...);
+ *
+ * This class uses the AddonManager AddonListener interface.
+ * When an add-on is installed, listeners are called in the following order:
+ * AL.onInstalling, AL.onInstalled
+ *
+ * For uninstalls, we see AL.onUninstalling then AL.onUninstalled.
+ *
+ * Enabling and disabling work by sending:
+ *
+ * AL.onEnabling, AL.onEnabled
+ * AL.onDisabling, AL.onDisabled
+ *
+ * Actions can be undone. All undoable actions notify the same
+ * AL.onOperationCancelled event. We treat this event like any other.
+ *
+ * When an add-on is uninstalled from about:addons, the user is offered an
+ * "Undo" option, which leads to the following sequence of events as
+ * observed by an AddonListener:
+ * Add-ons are first disabled then they are actually uninstalled. So, we will
+ * see AL.onDisabling and AL.onDisabled. The onUninstalling and onUninstalled
+ * events only come after the Addon Manager is closed or another view is
+ * switched to. In the case of Sync performing the uninstall, the uninstall
+ * events will occur immediately. However, we still see disabling events and
+ * heed them like they were normal. In the end, the state is proper.
+ */
+export function AddonsReconciler(queueCaller) {
+ this._log = Log.repository.getLogger("Sync.AddonsReconciler");
+ this._log.manageLevelFromPref("services.sync.log.logger.addonsreconciler");
+ this.queueCaller = queueCaller;
+
+ Svc.Obs.add("xpcom-shutdown", this.stopListening, this);
+}
+
+AddonsReconciler.prototype = {
+ /** Flag indicating whether we are listening to AddonManager events. */
+ _listening: false,
+
+ /**
+ * Define this as false if the reconciler should not persist state
+ * to disk when handling events.
+ *
+ * This allows test code to avoid spinning to write during observer
+ * notifications and xpcom shutdown, which appears to cause hangs on WinXP
+ * (Bug 873861).
+ */
+ _shouldPersist: true,
+
+ /** Log logger instance */
+ _log: null,
+
+ /**
+ * Container for add-on metadata.
+ *
+ * Keys are add-on IDs. Values are objects which describe the state of the
+ * add-on. This is a minimal mirror of data that can be queried from
+ * AddonManager. In some cases, we retain data longer than AddonManager.
+ */
+ _addons: {},
+
+ /**
+ * List of add-on changes over time.
+ *
+ * Each element is an array of [time, change, id].
+ */
+ _changes: [],
+
+ /**
+ * Objects subscribed to changes made to this instance.
+ */
+ _listeners: [],
+
+ /**
+ * Accessor for add-ons in this object.
+ *
+ * Returns an object mapping add-on IDs to objects containing metadata.
+ */
+ get addons() {
+ return this._addons;
+ },
+
+ async ensureStateLoaded() {
+ if (!this._promiseStateLoaded) {
+ this._promiseStateLoaded = this.loadState();
+ }
+ return this._promiseStateLoaded;
+ },
+
+ /**
+ * Load reconciler state from a file.
+ *
+ * The path is relative to the weave directory in the profile. If no
+ * path is given, the default one is used.
+ *
+ * If the file does not exist or there was an error parsing the file, the
+ * state will be transparently defined as empty.
+ *
+ * @param file
+ * Path to load. ".json" is appended automatically. If not defined,
+ * a default path will be consulted.
+ */
+ async loadState(file = DEFAULT_STATE_FILE) {
+ let json = await Utils.jsonLoad(file, this);
+ this._addons = {};
+ this._changes = [];
+
+ if (!json) {
+ this._log.debug("No data seen in loaded file: " + file);
+ return false;
+ }
+
+ let version = json.version;
+ if (!version || version != 1) {
+ this._log.error(
+ "Could not load JSON file because version not " +
+ "supported: " +
+ version
+ );
+ return false;
+ }
+
+ this._addons = json.addons;
+ for (let id in this._addons) {
+ let record = this._addons[id];
+ record.modified = new Date(record.modified);
+ }
+
+ for (let [time, change, id] of json.changes) {
+ this._changes.push([new Date(time), change, id]);
+ }
+
+ return true;
+ },
+
+ /**
+ * Saves the current state to a file in the local profile.
+ *
+ * @param file
+ * String path in profile to save to. If not defined, the default
+ * will be used.
+ */
+ async saveState(file = DEFAULT_STATE_FILE) {
+ let state = { version: 1, addons: {}, changes: [] };
+
+ for (let [id, record] of Object.entries(this._addons)) {
+ state.addons[id] = {};
+ for (let [k, v] of Object.entries(record)) {
+ if (k == "modified") {
+ state.addons[id][k] = v.getTime();
+ } else {
+ state.addons[id][k] = v;
+ }
+ }
+ }
+
+ for (let [time, change, id] of this._changes) {
+ state.changes.push([time.getTime(), change, id]);
+ }
+
+ this._log.info("Saving reconciler state to file: " + file);
+ await Utils.jsonSave(file, this, state);
+ },
+
+ /**
+ * Registers a change listener with this instance.
+ *
+ * Change listeners are called every time a change is recorded. The listener
+ * is an object with the function "changeListener" that takes 3 arguments,
+ * the Date at which the change happened, the type of change (a CHANGE_*
+ * constant), and the add-on state object reflecting the current state of
+ * the add-on at the time of the change.
+ *
+ * @param listener
+ * Object containing changeListener function.
+ */
+ addChangeListener: function addChangeListener(listener) {
+ if (!this._listeners.includes(listener)) {
+ this._log.debug("Adding change listener.");
+ this._listeners.push(listener);
+ }
+ },
+
+ /**
+ * Removes a previously-installed change listener from the instance.
+ *
+ * @param listener
+ * Listener instance to remove.
+ */
+ removeChangeListener: function removeChangeListener(listener) {
+ this._listeners = this._listeners.filter(element => {
+ if (element == listener) {
+ this._log.debug("Removing change listener.");
+ return false;
+ }
+ return true;
+ });
+ },
+
+ /**
+ * Tells the instance to start listening for AddonManager changes.
+ *
+ * This is typically called automatically when Sync is loaded.
+ */
+ startListening: function startListening() {
+ if (this._listening) {
+ return;
+ }
+
+ this._log.info("Registering as Add-on Manager listener.");
+ AddonManager.addAddonListener(this);
+ this._listening = true;
+ },
+
+ /**
+ * Tells the instance to stop listening for AddonManager changes.
+ *
+ * The reconciler should always be listening. This should only be called when
+ * the instance is being destroyed.
+ *
+ * This function will get called automatically on XPCOM shutdown. However, it
+ * is a best practice to call it yourself.
+ */
+ stopListening: function stopListening() {
+ if (!this._listening) {
+ return;
+ }
+
+ this._log.debug("Stopping listening and removing AddonManager listener.");
+ AddonManager.removeAddonListener(this);
+ this._listening = false;
+ },
+
+ /**
+ * Refreshes the global state of add-ons by querying the AddonManager.
+ */
+ async refreshGlobalState() {
+ this._log.info("Refreshing global state from AddonManager.");
+
+ let installs;
+ let addons = await AddonManager.getAllAddons();
+
+ let ids = {};
+
+ for (let addon of addons) {
+ ids[addon.id] = true;
+ await this.rectifyStateFromAddon(addon);
+ }
+
+ // Look for locally-defined add-ons that no longer exist and update their
+ // record.
+ for (let [id, addon] of Object.entries(this._addons)) {
+ if (id in ids) {
+ continue;
+ }
+
+ // If the id isn't in ids, it means that the add-on has been deleted or
+ // the add-on is in the process of being installed. We detect the
+ // latter by seeing if an AddonInstall is found for this add-on.
+
+ if (!installs) {
+ installs = await AddonManager.getAllInstalls();
+ }
+
+ let installFound = false;
+ for (let install of installs) {
+ if (
+ install.addon &&
+ install.addon.id == id &&
+ install.state == AddonManager.STATE_INSTALLED
+ ) {
+ installFound = true;
+ break;
+ }
+ }
+
+ if (installFound) {
+ continue;
+ }
+
+ if (addon.installed) {
+ addon.installed = false;
+ this._log.debug(
+ "Adding change because add-on not present in " +
+ "Add-on Manager: " +
+ id
+ );
+ await this._addChange(new Date(), CHANGE_UNINSTALLED, addon);
+ }
+ }
+
+ // See note for _shouldPersist.
+ if (this._shouldPersist) {
+ await this.saveState();
+ }
+ },
+
+ /**
+ * Rectifies the state of an add-on from an Addon instance.
+ *
+ * This basically says "given an Addon instance, assume it is truth and
+ * apply changes to the local state to reflect it."
+ *
+ * This function could result in change listeners being called if the local
+ * state differs from the passed add-on's state.
+ *
+ * @param addon
+ * Addon instance being updated.
+ */
+ async rectifyStateFromAddon(addon) {
+ this._log.debug(
+ `Rectifying state for addon ${addon.name} (version=${addon.version}, id=${addon.id})`
+ );
+
+ let id = addon.id;
+ let enabled = !addon.userDisabled;
+ let guid = addon.syncGUID;
+ let now = new Date();
+
+ if (!(id in this._addons)) {
+ let record = {
+ id,
+ guid,
+ enabled,
+ installed: true,
+ modified: now,
+ type: addon.type,
+ scope: addon.scope,
+ foreignInstall: addon.foreignInstall,
+ isSyncable: addon.isSyncable,
+ };
+ this._addons[id] = record;
+ this._log.debug(
+ "Adding change because add-on not present locally: " + id
+ );
+ await this._addChange(now, CHANGE_INSTALLED, record);
+ return;
+ }
+
+ let record = this._addons[id];
+ record.isSyncable = addon.isSyncable;
+
+ if (!record.installed) {
+ // It is possible the record is marked as uninstalled because an
+ // uninstall is pending.
+ if (!(addon.pendingOperations & AddonManager.PENDING_UNINSTALL)) {
+ record.installed = true;
+ record.modified = now;
+ }
+ }
+
+ if (record.enabled != enabled) {
+ record.enabled = enabled;
+ record.modified = now;
+ let change = enabled ? CHANGE_ENABLED : CHANGE_DISABLED;
+ this._log.debug("Adding change because enabled state changed: " + id);
+ await this._addChange(new Date(), change, record);
+ }
+
+ if (record.guid != guid) {
+ record.guid = guid;
+ // We don't record a change because the Sync engine rectifies this on its
+ // own. This is tightly coupled with Sync. If this code is ever lifted
+ // outside of Sync, this exception should likely be removed.
+ }
+ },
+
+ /**
+ * Record a change in add-on state.
+ *
+ * @param date
+ * Date at which the change occurred.
+ * @param change
+ * The type of the change. A CHANGE_* constant.
+ * @param state
+ * The new state of the add-on. From this.addons.
+ */
+ async _addChange(date, change, state) {
+ this._log.info("Change recorded for " + state.id);
+ this._changes.push([date, change, state.id]);
+
+ for (let listener of this._listeners) {
+ try {
+ await listener.changeListener(date, change, state);
+ } catch (ex) {
+ this._log.error("Exception calling change listener", ex);
+ }
+ }
+ },
+
+ /**
+ * Obtain the set of changes to add-ons since the date passed.
+ *
+ * This will return an array of arrays. Each entry in the array has the
+ * elements [date, change_type, id], where
+ *
+ * date - Date instance representing when the change occurred.
+ * change_type - One of CHANGE_* constants.
+ * id - ID of add-on that changed.
+ */
+ getChangesSinceDate(date) {
+ let length = this._changes.length;
+ for (let i = 0; i < length; i++) {
+ if (this._changes[i][0] >= date) {
+ return this._changes.slice(i);
+ }
+ }
+
+ return [];
+ },
+
+ /**
+ * Prunes all recorded changes from before the specified Date.
+ *
+ * @param date
+ * Entries older than this Date will be removed.
+ */
+ pruneChangesBeforeDate(date) {
+ this._changes = this._changes.filter(function test_age(change) {
+ return change[0] >= date;
+ });
+ },
+
+ /**
+ * Obtains the set of all known Sync GUIDs for add-ons.
+ */
+ getAllSyncGUIDs() {
+ let result = {};
+ for (let id in this.addons) {
+ result[id] = true;
+ }
+
+ return result;
+ },
+
+ /**
+ * Obtain the add-on state record for an add-on by Sync GUID.
+ *
+ * If the add-on could not be found, returns null.
+ *
+ * @param guid
+ * Sync GUID of add-on to retrieve.
+ */
+ getAddonStateFromSyncGUID(guid) {
+ for (let id in this.addons) {
+ let addon = this.addons[id];
+ if (addon.guid == guid) {
+ return addon;
+ }
+ }
+
+ return null;
+ },
+
+ /**
+ * Handler that is invoked as part of the AddonManager listeners.
+ */
+ async _handleListener(action, addon) {
+ // Since this is called as an observer, we explicitly trap errors and
+ // log them to ourselves so we don't see errors reported elsewhere.
+ try {
+ let id = addon.id;
+ this._log.debug("Add-on change: " + action + " to " + id);
+
+ switch (action) {
+ case "onEnabled":
+ case "onDisabled":
+ case "onInstalled":
+ case "onInstallEnded":
+ case "onOperationCancelled":
+ await this.rectifyStateFromAddon(addon);
+ break;
+
+ case "onUninstalled":
+ let id = addon.id;
+ let addons = this.addons;
+ if (id in addons) {
+ let now = new Date();
+ let record = addons[id];
+ record.installed = false;
+ record.modified = now;
+ this._log.debug(
+ "Adding change because of uninstall listener: " + id
+ );
+ await this._addChange(now, CHANGE_UNINSTALLED, record);
+ }
+ }
+
+ // See note for _shouldPersist.
+ if (this._shouldPersist) {
+ await this.saveState();
+ }
+ } catch (ex) {
+ this._log.warn("Exception", ex);
+ }
+ },
+
+ // AddonListeners
+ onEnabled: function onEnabled(addon) {
+ this.queueCaller.enqueueCall(() =>
+ this._handleListener("onEnabled", addon)
+ );
+ },
+ onDisabled: function onDisabled(addon) {
+ this.queueCaller.enqueueCall(() =>
+ this._handleListener("onDisabled", addon)
+ );
+ },
+ onInstalled: function onInstalled(addon) {
+ this.queueCaller.enqueueCall(() =>
+ this._handleListener("onInstalled", addon)
+ );
+ },
+ onUninstalled: function onUninstalled(addon) {
+ this.queueCaller.enqueueCall(() =>
+ this._handleListener("onUninstalled", addon)
+ );
+ },
+ onOperationCancelled: function onOperationCancelled(addon) {
+ this.queueCaller.enqueueCall(() =>
+ this._handleListener("onOperationCancelled", addon)
+ );
+ },
+};
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