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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
/**
* Session Storage and Restoration
*
* Overview
* This service reads user's session file at startup, and makes a determination
* as to whether the session should be restored. It will restore the session
* under the circumstances described below.
*
* Crash Detection
* The session file stores a session.state property, that
* indicates whether the browser is currently running. When the browser shuts
* down, the field is changed to "stopped". At startup, this field is read, and
* if it's value is "running", then it's assumed that the browser had previously
* crashed, or at the very least that something bad happened, and that we should
* restore the session.
*
* Forced Restarts
* In the event that a restart is required due to application update or extension
* installation, set the browser.sessionstore.resume_session_once pref to true,
* and the session will be restored the next time the browser starts.
*
* Always Resume
* This service will always resume the session if the integer pref
* browser.startup.page is set to 3.
*/
/* :::::::: Constants and Helpers ::::::::::::::: */
const STATE_RUNNING_STR = "running";
function debug(aMsg) {
Services.console.logStringMessage("SessionStartup: " + aMsg);
}
/* :::::::: The Service ::::::::::::::: */
function SessionStartup() {
}
SessionStartup.prototype = {
// the state to restore at startup
_initialState: null,
_sessionType: Ci.nsISessionStartup.NO_SESSION,
/* ........ Global Event Handlers .............. */
/**
* Initialize the component
*/
init: function sss_init() {
// get file references
let sessionFile = Services.dirsvc.get("ProfD", Ci.nsIFile);
sessionFile.append("sessionstore.json");
let doResumeSessionOnce = Services.prefs.getBoolPref("browser.sessionstore.resume_session_once");
let doResumeSession = doResumeSessionOnce ||
Services.prefs.getIntPref("browser.startup.page") == 3;
var resumeFromCrash = Services.prefs.getBoolPref("browser.sessionstore.resume_from_crash");
// only continue if the session file exists
if (!sessionFile.exists())
return;
// get string containing session state
let iniString = this._readStateFile(sessionFile);
if (!iniString)
return;
try {
// parse the session state into JS objects
this._initialState = JSON.parse(iniString);
}
catch (ex) {
doResumeSession = false;
debug("The session file is invalid: " + ex);
}
// If this is a normal restore then throw away any previous session
if (!doResumeSessionOnce && this._initialState)
delete this._initialState.lastSessionState;
let lastSessionCrashed =
this._initialState && this._initialState.session &&
this._initialState.session.state &&
this._initialState.session.state == STATE_RUNNING_STR;
// set the startup type
if (lastSessionCrashed && resumeFromCrash)
this._sessionType = Ci.nsISessionStartup.RECOVER_SESSION;
else if (!lastSessionCrashed && doResumeSession)
this._sessionType = Ci.nsISessionStartup.RESUME_SESSION;
else if (this._initialState)
this._sessionType = Ci.nsISessionStartup.DEFER_SESSION;
else
this._initialState = null; // reset the state
if (this.doRestore()) {
// wait for the first browser window to open
Services.obs.addObserver(this, "sessionstore-windows-restored", true);
}
},
/**
* Handle notifications
*/
observe: function sss_observe(aSubject, aTopic, aData) {
switch (aTopic) {
case "app-startup":
Services.obs.addObserver(this, "final-ui-startup", true);
Services.obs.addObserver(this, "quit-application", true);
break;
case "final-ui-startup":
Services.obs.removeObserver(this, "final-ui-startup");
Services.obs.removeObserver(this, "quit-application");
this.init();
break;
case "quit-application":
Services.obs.removeObserver(this, "final-ui-startup");
Services.obs.removeObserver(this, "quit-application");
break;
case "sessionstore-windows-restored":
// no need in repeating this, since session type won't change
Services.obs.removeObserver(this, "sessionstore-windows-restored");
// free _initialState after nsSessionStore is done with it
this._initialState = null;
// reset session type after restore
this._sessionType = Ci.nsISessionStartup.NO_SESSION;
break;
}
},
/* ........ Public API ................*/
/**
* Get the session state as a string
*/
get state() {
return this._initialState;
},
/**
* Determine whether there is a pending session restore.
* @returns bool
*/
doRestore: function sss_doRestore() {
return this._sessionType == Ci.nsISessionStartup.RECOVER_SESSION ||
this._sessionType == Ci.nsISessionStartup.RESUME_SESSION;
},
/**
* Get the type of pending session store, if any.
*/
get sessionType() {
return this._sessionType;
},
/* ........ Storage API .............. */
/**
* Reads a session state file into a string and lets
* observers modify the state before it's being used
*
* @param aFile is any nsIFile
* @returns a session state string
*/
_readStateFile: function sss_readStateFile(aFile) {
var stateString = Cc["@mozilla.org/supports-string;1"]
.createInstance(Ci.nsISupportsString);
stateString.data = this._readFile(aFile) || "";
Services.obs.notifyObservers(stateString, "sessionstore-state-read");
return stateString.data;
},
/**
* reads a file into a string
* @param aFile
* nsIFile
* @returns string
*/
_readFile: function sss_readFile(aFile) {
try {
var stream = Cc["@mozilla.org/network/file-input-stream;1"]
.createInstance(Ci.nsIFileInputStream);
stream.init(aFile, 0x01, 0, 0);
var cvStream = Cc["@mozilla.org/intl/converter-input-stream;1"]
.createInstance(Ci.nsIConverterInputStream);
cvStream.init(stream, "UTF-8", 1024, Ci.nsIConverterInputStream.DEFAULT_REPLACEMENT_CHARACTER);
var content = "";
var data = {};
while (cvStream.readString(4096, data)) {
content += data.value;
}
cvStream.close();
return content.replace(/\r\n?/g, "\n");
}
catch (ex) { Cu.reportError(ex); }
return null;
},
/* ........ QueryInterface .............. */
QueryInterface : XPCOMUtils.generateQI([Ci.nsIObserver,
Ci.nsISupportsWeakReference,
Ci.nsISessionStartup]),
classID: Components.ID("{4e6c1112-57b6-44ba-adf9-99fb573b0a30}")
};
var NSGetFactory = XPCOMUtils.generateNSGetFactory([SessionStartup]);