michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: #ifndef MERGED_COMPARTMENT
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = [
michael@0:   "SessionRecorder",
michael@0: ];
michael@0: 
michael@0: const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
michael@0: 
michael@0: #endif
michael@0: 
michael@0: Cu.import("resource://gre/modules/Preferences.jsm");
michael@0: Cu.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: Cu.import("resource://gre/modules/Log.jsm");
michael@0: Cu.import("resource://services-common/utils.js");
michael@0: 
michael@0: 
michael@0: // We automatically prune sessions older than this.
michael@0: const MAX_SESSION_AGE_MS = 7 * 24 * 60 * 60 * 1000; // 7 days.
michael@0: const STARTUP_RETRY_INTERVAL_MS = 5000;
michael@0: 
michael@0: // Wait up to 5 minutes for startup measurements before giving up.
michael@0: const MAX_STARTUP_TRIES = 300000 / STARTUP_RETRY_INTERVAL_MS;
michael@0: 
michael@0: /**
michael@0:  * Records information about browser sessions.
michael@0:  *
michael@0:  * This serves as an interface to both current session information as
michael@0:  * well as a history of previous sessions.
michael@0:  *
michael@0:  * Typically only one instance of this will be installed in an
michael@0:  * application. It is typically managed by an XPCOM service. The
michael@0:  * instance is instantiated at application start; onStartup is called
michael@0:  * once the profile is installed; onShutdown is called during shutdown.
michael@0:  *
michael@0:  * We currently record state in preferences. However, this should be
michael@0:  * invisible to external consumers. We could easily swap in a different
michael@0:  * storage mechanism if desired.
michael@0:  *
michael@0:  * Please note the different semantics for storing times and dates in
michael@0:  * preferences. Full dates (notably the session start time) are stored
michael@0:  * as strings because preferences have a 32-bit limit on integer values
michael@0:  * and milliseconds since UNIX epoch would overflow. Many times are
michael@0:  * stored as integer offsets from the session start time because they
michael@0:  * should not overflow 32 bits.
michael@0:  *
michael@0:  * Since this records history of all sessions, there is a possibility
michael@0:  * for unbounded data aggregation. This is curtailed through:
michael@0:  *
michael@0:  *   1) An "idle-daily" observer which delete sessions older than
michael@0:  *      MAX_SESSION_AGE_MS.
michael@0:  *   2) The creator of this instance explicitly calling
michael@0:  *      `pruneOldSessions`.
michael@0:  *
michael@0:  * @param branch
michael@0:  *        (string) Preferences branch on which to record state.
michael@0:  */
michael@0: this.SessionRecorder = function (branch) {
michael@0:   if (!branch) {
michael@0:     throw new Error("branch argument must be defined.");
michael@0:   }
michael@0: 
michael@0:   if (!branch.endsWith(".")) {
michael@0:     throw new Error("branch argument must end with '.': " + branch);
michael@0:   }
michael@0: 
michael@0:   this._log = Log.repository.getLogger("Services.DataReporting.SessionRecorder");
michael@0: 
michael@0:   this._prefs = new Preferences(branch);
michael@0:   this._lastActivityWasInactive = false;
michael@0:   this._activeTicks = 0;
michael@0:   this.fineTotalTime = 0;
michael@0:   this._started = false;
michael@0:   this._timer = null;
michael@0:   this._startupFieldTries = 0;
michael@0: 
michael@0:   this._os = Cc["@mozilla.org/observer-service;1"]
michael@0:                .getService(Ci.nsIObserverService);
michael@0: 
michael@0: };
michael@0: 
michael@0: SessionRecorder.prototype = Object.freeze({
michael@0:   QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver]),
michael@0: 
michael@0:   STARTUP_RETRY_INTERVAL_MS: STARTUP_RETRY_INTERVAL_MS,
michael@0: 
michael@0:   get _currentIndex() {
michael@0:     return this._prefs.get("currentIndex", 0);
michael@0:   },
michael@0: 
michael@0:   set _currentIndex(value) {
michael@0:     this._prefs.set("currentIndex", value);
michael@0:   },
michael@0: 
michael@0:   get _prunedIndex() {
michael@0:     return this._prefs.get("prunedIndex", 0);
michael@0:   },
michael@0: 
michael@0:   set _prunedIndex(value) {
michael@0:     this._prefs.set("prunedIndex", value);
michael@0:   },
michael@0: 
michael@0:   get startDate() {
michael@0:     return CommonUtils.getDatePref(this._prefs, "current.startTime");
michael@0:   },
michael@0: 
michael@0:   set _startDate(value) {
michael@0:     CommonUtils.setDatePref(this._prefs, "current.startTime", value);
michael@0:   },
michael@0: 
michael@0:   get activeTicks() {
michael@0:     return this._prefs.get("current.activeTicks", 0);
michael@0:   },
michael@0: 
michael@0:   incrementActiveTicks: function () {
michael@0:     this._prefs.set("current.activeTicks", ++this._activeTicks);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Total time of this session in integer seconds.
michael@0:    *
michael@0:    * See also fineTotalTime for the time in milliseconds.
michael@0:    */
michael@0:   get totalTime() {
michael@0:     return this._prefs.get("current.totalTime", 0);
michael@0:   },
michael@0: 
michael@0:   updateTotalTime: function () {
michael@0:     // We store millisecond precision internally to prevent drift from
michael@0:     // repeated rounding.
michael@0:     this.fineTotalTime = Date.now() - this.startDate;
michael@0:     this._prefs.set("current.totalTime", Math.floor(this.fineTotalTime / 1000));
michael@0:   },
michael@0: 
michael@0:   get main() {
michael@0:     return this._prefs.get("current.main", -1);
michael@0:   },
michael@0: 
michael@0:   set _main(value) {
michael@0:     if (!Number.isInteger(value)) {
michael@0:       throw new Error("main time must be an integer.");
michael@0:     }
michael@0: 
michael@0:     this._prefs.set("current.main", value);
michael@0:   },
michael@0: 
michael@0:   get firstPaint() {
michael@0:     return this._prefs.get("current.firstPaint", -1);
michael@0:   },
michael@0: 
michael@0:   set _firstPaint(value) {
michael@0:     if (!Number.isInteger(value)) {
michael@0:       throw new Error("firstPaint must be an integer.");
michael@0:     }
michael@0: 
michael@0:     this._prefs.set("current.firstPaint", value);
michael@0:   },
michael@0: 
michael@0:   get sessionRestored() {
michael@0:     return this._prefs.get("current.sessionRestored", -1);
michael@0:   },
michael@0: 
michael@0:   set _sessionRestored(value) {
michael@0:     if (!Number.isInteger(value)) {
michael@0:       throw new Error("sessionRestored must be an integer.");
michael@0:     }
michael@0: 
michael@0:     this._prefs.set("current.sessionRestored", value);
michael@0:   },
michael@0: 
michael@0:   getPreviousSessions: function () {
michael@0:     let result = {};
michael@0: 
michael@0:     for (let i = this._prunedIndex; i < this._currentIndex; i++) {
michael@0:       let s = this.getPreviousSession(i);
michael@0:       if (!s) {
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       result[i] = s;
michael@0:     }
michael@0: 
michael@0:     return result;
michael@0:   },
michael@0: 
michael@0:   getPreviousSession: function (index) {
michael@0:     return this._deserialize(this._prefs.get("previous." + index));
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Prunes old, completed sessions that started earlier than the
michael@0:    * specified date.
michael@0:    */
michael@0:   pruneOldSessions: function (date) {
michael@0:     for (let i = this._prunedIndex; i < this._currentIndex; i++) {
michael@0:       let s = this.getPreviousSession(i);
michael@0:       if (!s) {
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       if (s.startDate >= date) {
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       this._log.debug("Pruning session #" + i + ".");
michael@0:       this._prefs.reset("previous." + i);
michael@0:       this._prunedIndex = i;
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   recordStartupFields: function () {
michael@0:     let si = this._getStartupInfo();
michael@0: 
michael@0:     if (!si.process) {
michael@0:       throw new Error("Startup info not available.");
michael@0:     }
michael@0: 
michael@0:     let missing = false;
michael@0: 
michael@0:     for (let field of ["main", "firstPaint", "sessionRestored"]) {
michael@0:       if (!(field in si)) {
michael@0:         this._log.debug("Missing startup field: " + field);
michael@0:         missing = true;
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       this["_" + field] = si[field].getTime() - si.process.getTime();
michael@0:     }
michael@0: 
michael@0:     if (!missing || this._startupFieldTries > MAX_STARTUP_TRIES) {
michael@0:       this._clearStartupTimer();
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     // If we have missing fields, install a timer and keep waiting for
michael@0:     // data.
michael@0:     this._startupFieldTries++;
michael@0: 
michael@0:     if (!this._timer) {
michael@0:       this._timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
michael@0:       this._timer.initWithCallback({
michael@0:         notify: this.recordStartupFields.bind(this),
michael@0:       }, this.STARTUP_RETRY_INTERVAL_MS, this._timer.TYPE_REPEATING_SLACK);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   _clearStartupTimer: function () {
michael@0:     if (this._timer) {
michael@0:       this._timer.cancel();
michael@0:       delete this._timer;
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Perform functionality on application startup.
michael@0:    *
michael@0:    * This is typically called in a "profile-do-change" handler.
michael@0:    */
michael@0:   onStartup: function () {
michael@0:     if (this._started) {
michael@0:       throw new Error("onStartup has already been called.");
michael@0:     }
michael@0: 
michael@0:     let si = this._getStartupInfo();
michael@0:     if (!si.process) {
michael@0:       throw new Error("Process information not available. Misconfigured app?");
michael@0:     }
michael@0: 
michael@0:     this._started = true;
michael@0: 
michael@0:     this._os.addObserver(this, "profile-before-change", false);
michael@0:     this._os.addObserver(this, "user-interaction-active", false);
michael@0:     this._os.addObserver(this, "user-interaction-inactive", false);
michael@0:     this._os.addObserver(this, "idle-daily", false);
michael@0: 
michael@0:     // This has the side-effect of clearing current session state.
michael@0:     this._moveCurrentToPrevious();
michael@0: 
michael@0:     this._startDate = si.process;
michael@0:     this._prefs.set("current.activeTicks", 0);
michael@0:     this.updateTotalTime();
michael@0: 
michael@0:     this.recordStartupFields();
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Record application activity.
michael@0:    */
michael@0:   onActivity: function (active) {
michael@0:     let updateActive = active && !this._lastActivityWasInactive;
michael@0:     this._lastActivityWasInactive = !active;
michael@0: 
michael@0:     this.updateTotalTime();
michael@0: 
michael@0:     if (updateActive) {
michael@0:       this.incrementActiveTicks();
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   onShutdown: function () {
michael@0:     this._log.info("Recording clean session shutdown.");
michael@0:     this._prefs.set("current.clean", true);
michael@0:     this.updateTotalTime();
michael@0:     this._clearStartupTimer();
michael@0: 
michael@0:     this._os.removeObserver(this, "profile-before-change");
michael@0:     this._os.removeObserver(this, "user-interaction-active");
michael@0:     this._os.removeObserver(this, "user-interaction-inactive");
michael@0:     this._os.removeObserver(this, "idle-daily");
michael@0:   },
michael@0: 
michael@0:   _CURRENT_PREFS: [
michael@0:     "current.startTime",
michael@0:     "current.activeTicks",
michael@0:     "current.totalTime",
michael@0:     "current.main",
michael@0:     "current.firstPaint",
michael@0:     "current.sessionRestored",
michael@0:     "current.clean",
michael@0:   ],
michael@0: 
michael@0:   // This is meant to be called only during onStartup().
michael@0:   _moveCurrentToPrevious: function () {
michael@0:     try {
michael@0:       if (!this.startDate.getTime()) {
michael@0:         this._log.info("No previous session. Is this first app run?");
michael@0:         return;
michael@0:       }
michael@0: 
michael@0:       let clean = this._prefs.get("current.clean", false);
michael@0: 
michael@0:       let count = this._currentIndex++;
michael@0:       let obj = {
michael@0:         s: this.startDate.getTime(),
michael@0:         a: this.activeTicks,
michael@0:         t: this.totalTime,
michael@0:         c: clean,
michael@0:         m: this.main,
michael@0:         fp: this.firstPaint,
michael@0:         sr: this.sessionRestored,
michael@0:       };
michael@0: 
michael@0:       this._log.debug("Recording last sessions as #" + count + ".");
michael@0:       this._prefs.set("previous." + count, JSON.stringify(obj));
michael@0:     } catch (ex) {
michael@0:       this._log.warn("Exception when migrating last session: " +
michael@0:                      CommonUtils.exceptionStr(ex));
michael@0:     } finally {
michael@0:       this._log.debug("Resetting prefs from last session.");
michael@0:       for (let pref of this._CURRENT_PREFS) {
michael@0:         this._prefs.reset(pref);
michael@0:       }
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   _deserialize: function (s) {
michael@0:     let o;
michael@0:     try {
michael@0:       o = JSON.parse(s);
michael@0:     } catch (ex) {
michael@0:       return null;
michael@0:     }
michael@0: 
michael@0:     return {
michael@0:       startDate: new Date(o.s),
michael@0:       activeTicks: o.a,
michael@0:       totalTime: o.t,
michael@0:       clean: !!o.c,
michael@0:       main: o.m,
michael@0:       firstPaint: o.fp,
michael@0:       sessionRestored: o.sr,
michael@0:     };
michael@0:   },
michael@0: 
michael@0:   // Implemented as a function to allow for monkeypatching in tests.
michael@0:   _getStartupInfo: function () {
michael@0:     return Cc["@mozilla.org/toolkit/app-startup;1"]
michael@0:              .getService(Ci.nsIAppStartup)
michael@0:              .getStartupInfo();
michael@0:   },
michael@0: 
michael@0:   observe: function (subject, topic, data) {
michael@0:     switch (topic) {
michael@0:       case "profile-before-change":
michael@0:         this.onShutdown();
michael@0:         break;
michael@0: 
michael@0:       case "user-interaction-active":
michael@0:         this.onActivity(true);
michael@0:         break;
michael@0: 
michael@0:       case "user-interaction-inactive":
michael@0:         this.onActivity(false);
michael@0:         break;
michael@0: 
michael@0:       case "idle-daily":
michael@0:         this.pruneOldSessions(new Date(Date.now() - MAX_SESSION_AGE_MS));
michael@0:         break;
michael@0:     }
michael@0:   },
michael@0: });