1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/browser/components/sessionstore/src/nsSessionStartup.js Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,354 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +"use strict";
1.9 +
1.10 +/**
1.11 + * Session Storage and Restoration
1.12 + *
1.13 + * Overview
1.14 + * This service reads user's session file at startup, and makes a determination
1.15 + * as to whether the session should be restored. It will restore the session
1.16 + * under the circumstances described below. If the auto-start Private Browsing
1.17 + * mode is active, however, the session is never restored.
1.18 + *
1.19 + * Crash Detection
1.20 + * The CrashMonitor is used to check if the final session state was successfully
1.21 + * written at shutdown of the last session. If we did not reach
1.22 + * 'sessionstore-final-state-write-complete', then it's assumed that the browser
1.23 + * has previously crashed and we should restore the session.
1.24 + *
1.25 + * Forced Restarts
1.26 + * In the event that a restart is required due to application update or extension
1.27 + * installation, set the browser.sessionstore.resume_session_once pref to true,
1.28 + * and the session will be restored the next time the browser starts.
1.29 + *
1.30 + * Always Resume
1.31 + * This service will always resume the session if the integer pref
1.32 + * browser.startup.page is set to 3.
1.33 + */
1.34 +
1.35 +/* :::::::: Constants and Helpers ::::::::::::::: */
1.36 +
1.37 +const Cc = Components.classes;
1.38 +const Ci = Components.interfaces;
1.39 +const Cr = Components.results;
1.40 +const Cu = Components.utils;
1.41 +Cu.import("resource://gre/modules/XPCOMUtils.jsm");
1.42 +Cu.import("resource://gre/modules/Services.jsm");
1.43 +Cu.import("resource://gre/modules/TelemetryStopwatch.jsm");
1.44 +Cu.import("resource://gre/modules/PrivateBrowsingUtils.jsm");
1.45 +Cu.import("resource://gre/modules/Promise.jsm");
1.46 +
1.47 +XPCOMUtils.defineLazyModuleGetter(this, "console",
1.48 + "resource://gre/modules/devtools/Console.jsm");
1.49 +XPCOMUtils.defineLazyModuleGetter(this, "SessionFile",
1.50 + "resource:///modules/sessionstore/SessionFile.jsm");
1.51 +XPCOMUtils.defineLazyModuleGetter(this, "CrashMonitor",
1.52 + "resource://gre/modules/CrashMonitor.jsm");
1.53 +
1.54 +const STATE_RUNNING_STR = "running";
1.55 +
1.56 +// 'browser.startup.page' preference value to resume the previous session.
1.57 +const BROWSER_STARTUP_RESUME_SESSION = 3;
1.58 +
1.59 +function debug(aMsg) {
1.60 + aMsg = ("SessionStartup: " + aMsg).replace(/\S{80}/g, "$&\n");
1.61 + Services.console.logStringMessage(aMsg);
1.62 +}
1.63 +
1.64 +let gOnceInitializedDeferred = Promise.defer();
1.65 +
1.66 +/* :::::::: The Service ::::::::::::::: */
1.67 +
1.68 +function SessionStartup() {
1.69 +}
1.70 +
1.71 +SessionStartup.prototype = {
1.72 +
1.73 + // the state to restore at startup
1.74 + _initialState: null,
1.75 + _sessionType: Ci.nsISessionStartup.NO_SESSION,
1.76 + _initialized: false,
1.77 +
1.78 + // Stores whether the previous session crashed.
1.79 + _previousSessionCrashed: null,
1.80 +
1.81 +/* ........ Global Event Handlers .............. */
1.82 +
1.83 + /**
1.84 + * Initialize the component
1.85 + */
1.86 + init: function sss_init() {
1.87 + Services.obs.notifyObservers(null, "sessionstore-init-started", null);
1.88 +
1.89 + // do not need to initialize anything in auto-started private browsing sessions
1.90 + if (PrivateBrowsingUtils.permanentPrivateBrowsing) {
1.91 + this._initialized = true;
1.92 + gOnceInitializedDeferred.resolve();
1.93 + return;
1.94 + }
1.95 +
1.96 + SessionFile.read().then(
1.97 + this._onSessionFileRead.bind(this),
1.98 + console.error
1.99 + );
1.100 + },
1.101 +
1.102 + // Wrap a string as a nsISupports
1.103 + _createSupportsString: function ssfi_createSupportsString(aData) {
1.104 + let string = Cc["@mozilla.org/supports-string;1"]
1.105 + .createInstance(Ci.nsISupportsString);
1.106 + string.data = aData;
1.107 + return string;
1.108 + },
1.109 +
1.110 + /**
1.111 + * Complete initialization once the Session File has been read
1.112 + *
1.113 + * @param stateString
1.114 + * string The Session State string read from disk
1.115 + */
1.116 + _onSessionFileRead: function (stateString) {
1.117 + this._initialized = true;
1.118 +
1.119 + // Let observers modify the state before it is used
1.120 + let supportsStateString = this._createSupportsString(stateString);
1.121 + Services.obs.notifyObservers(supportsStateString, "sessionstore-state-read", "");
1.122 + stateString = supportsStateString.data;
1.123 +
1.124 + // No valid session found.
1.125 + if (!stateString) {
1.126 + this._sessionType = Ci.nsISessionStartup.NO_SESSION;
1.127 + Services.obs.notifyObservers(null, "sessionstore-state-finalized", "");
1.128 + gOnceInitializedDeferred.resolve();
1.129 + return;
1.130 + }
1.131 +
1.132 + this._initialState = this._parseStateString(stateString);
1.133 +
1.134 + let shouldResumeSessionOnce = Services.prefs.getBoolPref("browser.sessionstore.resume_session_once");
1.135 + let shouldResumeSession = shouldResumeSessionOnce ||
1.136 + Services.prefs.getIntPref("browser.startup.page") == BROWSER_STARTUP_RESUME_SESSION;
1.137 +
1.138 + // If this is a normal restore then throw away any previous session
1.139 + if (!shouldResumeSessionOnce && this._initialState) {
1.140 + delete this._initialState.lastSessionState;
1.141 + }
1.142 +
1.143 + let resumeFromCrash = Services.prefs.getBoolPref("browser.sessionstore.resume_from_crash");
1.144 +
1.145 + CrashMonitor.previousCheckpoints.then(checkpoints => {
1.146 + if (checkpoints) {
1.147 + // If the previous session finished writing the final state, we'll
1.148 + // assume there was no crash.
1.149 + this._previousSessionCrashed = !checkpoints["sessionstore-final-state-write-complete"];
1.150 + } else {
1.151 + // If the Crash Monitor could not load a checkpoints file it will
1.152 + // provide null. This could occur on the first run after updating to
1.153 + // a version including the Crash Monitor, or if the checkpoints file
1.154 + // was removed.
1.155 + //
1.156 + // If this is the first run after an update, sessionstore.js should
1.157 + // still contain the session.state flag to indicate if the session
1.158 + // crashed. If it is not present, we will assume this was not the first
1.159 + // run after update and the checkpoints file was somehow corrupted or
1.160 + // removed by a crash.
1.161 + //
1.162 + // If the session.state flag is present, we will fallback to using it
1.163 + // for crash detection - If the last write of sessionstore.js had it
1.164 + // set to "running", we crashed.
1.165 + let stateFlagPresent = (this._initialState &&
1.166 + this._initialState.session &&
1.167 + this._initialState.session.state);
1.168 +
1.169 +
1.170 + this._previousSessionCrashed = !stateFlagPresent ||
1.171 + (this._initialState.session.state == STATE_RUNNING_STR);
1.172 + }
1.173 +
1.174 + // Report shutdown success via telemetry. Shortcoming here are
1.175 + // being-killed-by-OS-shutdown-logic, shutdown freezing after
1.176 + // session restore was written, etc.
1.177 + Services.telemetry.getHistogramById("SHUTDOWN_OK").add(!this._previousSessionCrashed);
1.178 +
1.179 + // set the startup type
1.180 + if (this._previousSessionCrashed && resumeFromCrash)
1.181 + this._sessionType = Ci.nsISessionStartup.RECOVER_SESSION;
1.182 + else if (!this._previousSessionCrashed && shouldResumeSession)
1.183 + this._sessionType = Ci.nsISessionStartup.RESUME_SESSION;
1.184 + else if (this._initialState)
1.185 + this._sessionType = Ci.nsISessionStartup.DEFER_SESSION;
1.186 + else
1.187 + this._initialState = null; // reset the state
1.188 +
1.189 + Services.obs.addObserver(this, "sessionstore-windows-restored", true);
1.190 +
1.191 + if (this._sessionType != Ci.nsISessionStartup.NO_SESSION)
1.192 + Services.obs.addObserver(this, "browser:purge-session-history", true);
1.193 +
1.194 + // We're ready. Notify everyone else.
1.195 + Services.obs.notifyObservers(null, "sessionstore-state-finalized", "");
1.196 + gOnceInitializedDeferred.resolve();
1.197 + });
1.198 + },
1.199 +
1.200 +
1.201 + /**
1.202 + * Convert the Session State string into a state object
1.203 + *
1.204 + * @param stateString
1.205 + * string The Session State string read from disk
1.206 + * @returns {State} a Session State object
1.207 + */
1.208 + _parseStateString: function (stateString) {
1.209 + let state = null;
1.210 + let corruptFile = false;
1.211 +
1.212 + try {
1.213 + state = JSON.parse(stateString);
1.214 + } catch (ex) {
1.215 + debug("The session file contained un-parse-able JSON: " + ex);
1.216 + corruptFile = true;
1.217 + }
1.218 + Services.telemetry.getHistogramById("FX_SESSION_RESTORE_CORRUPT_FILE").add(corruptFile);
1.219 +
1.220 + return state;
1.221 + },
1.222 +
1.223 + /**
1.224 + * Handle notifications
1.225 + */
1.226 + observe: function sss_observe(aSubject, aTopic, aData) {
1.227 + switch (aTopic) {
1.228 + case "app-startup":
1.229 + Services.obs.addObserver(this, "final-ui-startup", true);
1.230 + Services.obs.addObserver(this, "quit-application", true);
1.231 + break;
1.232 + case "final-ui-startup":
1.233 + Services.obs.removeObserver(this, "final-ui-startup");
1.234 + Services.obs.removeObserver(this, "quit-application");
1.235 + this.init();
1.236 + break;
1.237 + case "quit-application":
1.238 + // no reason for initializing at this point (cf. bug 409115)
1.239 + Services.obs.removeObserver(this, "final-ui-startup");
1.240 + Services.obs.removeObserver(this, "quit-application");
1.241 + if (this._sessionType != Ci.nsISessionStartup.NO_SESSION)
1.242 + Services.obs.removeObserver(this, "browser:purge-session-history");
1.243 + break;
1.244 + case "sessionstore-windows-restored":
1.245 + Services.obs.removeObserver(this, "sessionstore-windows-restored");
1.246 + // free _initialState after nsSessionStore is done with it
1.247 + this._initialState = null;
1.248 + break;
1.249 + case "browser:purge-session-history":
1.250 + Services.obs.removeObserver(this, "browser:purge-session-history");
1.251 + // reset all state on sanitization
1.252 + this._sessionType = Ci.nsISessionStartup.NO_SESSION;
1.253 + break;
1.254 + }
1.255 + },
1.256 +
1.257 +/* ........ Public API ................*/
1.258 +
1.259 + get onceInitialized() {
1.260 + return gOnceInitializedDeferred.promise;
1.261 + },
1.262 +
1.263 + /**
1.264 + * Get the session state as a jsval
1.265 + */
1.266 + get state() {
1.267 + this._ensureInitialized();
1.268 + return this._initialState;
1.269 + },
1.270 +
1.271 + /**
1.272 + * Determines whether there is a pending session restore. Should only be
1.273 + * called after initialization has completed.
1.274 + * @throws Error if initialization is not complete yet.
1.275 + * @returns bool
1.276 + */
1.277 + doRestore: function sss_doRestore() {
1.278 + this._ensureInitialized();
1.279 + return this._willRestore();
1.280 + },
1.281 +
1.282 + /**
1.283 + * Determines whether automatic session restoration is enabled for this
1.284 + * launch of the browser. This does not include crash restoration. In
1.285 + * particular, if session restore is configured to restore only in case of
1.286 + * crash, this method returns false.
1.287 + * @returns bool
1.288 + */
1.289 + isAutomaticRestoreEnabled: function () {
1.290 + return Services.prefs.getBoolPref("browser.sessionstore.resume_session_once") ||
1.291 + Services.prefs.getIntPref("browser.startup.page") == BROWSER_STARTUP_RESUME_SESSION;
1.292 + },
1.293 +
1.294 + /**
1.295 + * Determines whether there is a pending session restore.
1.296 + * @returns bool
1.297 + */
1.298 + _willRestore: function () {
1.299 + return this._sessionType == Ci.nsISessionStartup.RECOVER_SESSION ||
1.300 + this._sessionType == Ci.nsISessionStartup.RESUME_SESSION;
1.301 + },
1.302 +
1.303 + /**
1.304 + * Returns whether we will restore a session that ends up replacing the
1.305 + * homepage. The browser uses this to not start loading the homepage if
1.306 + * we're going to stop its load anyway shortly after.
1.307 + *
1.308 + * This is meant to be an optimization for the average case that loading the
1.309 + * session file finishes before we may want to start loading the default
1.310 + * homepage. Should this be called before the session file has been read it
1.311 + * will just return false.
1.312 + *
1.313 + * @returns bool
1.314 + */
1.315 + get willOverrideHomepage() {
1.316 + if (this._initialState && this._willRestore()) {
1.317 + let windows = this._initialState.windows || null;
1.318 + // If there are valid windows with not only pinned tabs, signal that we
1.319 + // will override the default homepage by restoring a session.
1.320 + return windows && windows.some(w => w.tabs.some(t => !t.pinned));
1.321 + }
1.322 + return false;
1.323 + },
1.324 +
1.325 + /**
1.326 + * Get the type of pending session store, if any.
1.327 + */
1.328 + get sessionType() {
1.329 + this._ensureInitialized();
1.330 + return this._sessionType;
1.331 + },
1.332 +
1.333 + /**
1.334 + * Get whether the previous session crashed.
1.335 + */
1.336 + get previousSessionCrashed() {
1.337 + this._ensureInitialized();
1.338 + return this._previousSessionCrashed;
1.339 + },
1.340 +
1.341 + // Ensure that initialization is complete. If initialization is not complete
1.342 + // yet, something is attempting to use the old synchronous initialization,
1.343 + // throw an error.
1.344 + _ensureInitialized: function sss__ensureInitialized() {
1.345 + if (!this._initialized) {
1.346 + throw new Error("Session Store is not initialized.");
1.347 + }
1.348 + },
1.349 +
1.350 + /* ........ QueryInterface .............. */
1.351 + QueryInterface : XPCOMUtils.generateQI([Ci.nsIObserver,
1.352 + Ci.nsISupportsWeakReference,
1.353 + Ci.nsISessionStartup]),
1.354 + classID: Components.ID("{ec7a6c20-e081-11da-8ad9-0800200c9a66}")
1.355 +};
1.356 +
1.357 +this.NSGetFactory = XPCOMUtils.generateNSGetFactory([SessionStartup]);
