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Diffstat (limited to 'browser/components/sessionstore/SessionStartup.sys.mjs')
| -rw-r--r-- | browser/components/sessionstore/SessionStartup.sys.mjs | 415 |
1 files changed, 415 insertions, 0 deletions
diff --git a/browser/components/sessionstore/SessionStartup.sys.mjs b/browser/components/sessionstore/SessionStartup.sys.mjs new file mode 100644 index 0000000000..f151989161 --- /dev/null +++ b/browser/components/sessionstore/SessionStartup.sys.mjs @@ -0,0 +1,415 @@ +/* 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/. */ + +/** + * 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. If the auto-start Private Browsing + * mode is active, however, the session is never restored. + * + * Crash Detection + * The CrashMonitor is used to check if the final session state was successfully + * written at shutdown of the last session. If we did not reach + * 'sessionstore-final-state-write-complete', then it's assumed that the browser + * has previously crashed and 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 lazy = {}; + +ChromeUtils.defineESModuleGetters(lazy, { + CrashMonitor: "resource://gre/modules/CrashMonitor.sys.mjs", + PrivateBrowsingUtils: "resource://gre/modules/PrivateBrowsingUtils.sys.mjs", + SessionFile: "resource:///modules/sessionstore/SessionFile.sys.mjs", + StartupPerformance: + "resource:///modules/sessionstore/StartupPerformance.sys.mjs", +}); + +const STATE_RUNNING_STR = "running"; + +const TYPE_NO_SESSION = 0; +const TYPE_RECOVER_SESSION = 1; +const TYPE_RESUME_SESSION = 2; +const TYPE_DEFER_SESSION = 3; + +// 'browser.startup.page' preference value to resume the previous session. +const BROWSER_STARTUP_RESUME_SESSION = 3; + +function warning(msg, exception) { + let consoleMsg = Cc["@mozilla.org/scripterror;1"].createInstance( + Ci.nsIScriptError + ); + consoleMsg.init( + msg, + exception.fileName, + null, + exception.lineNumber, + 0, + Ci.nsIScriptError.warningFlag, + "component javascript" + ); + Services.console.logMessage(consoleMsg); +} + +var gOnceInitializedDeferred = (function () { + let deferred = {}; + + deferred.promise = new Promise((resolve, reject) => { + deferred.resolve = resolve; + deferred.reject = reject; + }); + + return deferred; +})(); + +/* :::::::: The Service ::::::::::::::: */ + +export var SessionStartup = { + NO_SESSION: TYPE_NO_SESSION, + RECOVER_SESSION: TYPE_RECOVER_SESSION, + RESUME_SESSION: TYPE_RESUME_SESSION, + DEFER_SESSION: TYPE_DEFER_SESSION, + + // The state to restore at startup. + _initialState: null, + _sessionType: null, + _initialized: false, + + // Stores whether the previous session crashed. + _previousSessionCrashed: null, + + _resumeSessionEnabled: null, + + /* ........ Global Event Handlers .............. */ + + /** + * Initialize the component + */ + init() { + Services.obs.notifyObservers(null, "sessionstore-init-started"); + lazy.StartupPerformance.init(); + + // do not need to initialize anything in auto-started private browsing sessions + if (lazy.PrivateBrowsingUtils.permanentPrivateBrowsing) { + this._initialized = true; + gOnceInitializedDeferred.resolve(); + return; + } + + if ( + Services.prefs.getBoolPref( + "browser.sessionstore.resuming_after_os_restart" + ) + ) { + if (!Services.appinfo.restartedByOS) { + // We had set resume_session_once in order to resume after an OS restart, + // but we aren't automatically started by the OS (or else appinfo.restartedByOS + // would have been set). Therefore we should clear resume_session_once + // to avoid forcing a resume for a normal startup. + Services.prefs.setBoolPref( + "browser.sessionstore.resume_session_once", + false + ); + } + Services.prefs.setBoolPref( + "browser.sessionstore.resuming_after_os_restart", + false + ); + } + + lazy.SessionFile.read().then( + this._onSessionFileRead.bind(this), + console.error + ); + }, + + // Wrap a string as a nsISupports. + _createSupportsString(data) { + let string = Cc["@mozilla.org/supports-string;1"].createInstance( + Ci.nsISupportsString + ); + string.data = data; + return string; + }, + + /** + * Complete initialization once the Session File has been read. + * + * @param source The Session State string read from disk. + * @param parsed The object obtained by parsing |source| as JSON. + */ + _onSessionFileRead({ source, parsed, noFilesFound }) { + this._initialized = true; + + // Let observers modify the state before it is used + let supportsStateString = this._createSupportsString(source); + Services.obs.notifyObservers( + supportsStateString, + "sessionstore-state-read" + ); + let stateString = supportsStateString.data; + + if (stateString != source) { + // The session has been modified by an add-on, reparse. + try { + this._initialState = JSON.parse(stateString); + } catch (ex) { + // That's not very good, an add-on has rewritten the initial + // state to something that won't parse. + warning("Observer rewrote the state to something that won't parse", ex); + } + } else { + // No need to reparse + this._initialState = parsed; + } + + if (this._initialState == null) { + // No valid session found. + this._sessionType = this.NO_SESSION; + Services.obs.notifyObservers(null, "sessionstore-state-finalized"); + gOnceInitializedDeferred.resolve(); + return; + } + + let initialState = this._initialState; + Services.tm.idleDispatchToMainThread(() => { + let pinnedTabCount = initialState.windows.reduce((winAcc, win) => { + return ( + winAcc + + win.tabs.reduce((tabAcc, tab) => { + return tabAcc + (tab.pinned ? 1 : 0); + }, 0) + ); + }, 0); + Services.telemetry.scalarSetMaximum( + "browser.engagement.max_concurrent_tab_pinned_count", + pinnedTabCount + ); + }, 60000); + + // If this is a normal restore then throw away any previous session. + if (!this.isAutomaticRestoreEnabled() && this._initialState) { + delete this._initialState.lastSessionState; + } + + lazy.CrashMonitor.previousCheckpoints.then(checkpoints => { + if (checkpoints) { + // If the previous session finished writing the final state, we'll + // assume there was no crash. + this._previousSessionCrashed = + !checkpoints["sessionstore-final-state-write-complete"]; + } else if (noFilesFound) { + // If the Crash Monitor could not load a checkpoints file it will + // provide null. This could occur on the first run after updating to + // a version including the Crash Monitor, or if the checkpoints file + // was removed, or on first startup with this profile, or after Firefox Reset. + + // There was no checkpoints file and no sessionstore.js or its backups, + // so we will assume that this was a fresh profile. + this._previousSessionCrashed = false; + } else { + // If this is the first run after an update, sessionstore.js should + // still contain the session.state flag to indicate if the session + // crashed. If it is not present, we will assume this was not the first + // run after update and the checkpoints file was somehow corrupted or + // removed by a crash. + // + // If the session.state flag is present, we will fallback to using it + // for crash detection - If the last write of sessionstore.js had it + // set to "running", we crashed. + let stateFlagPresent = + this._initialState.session && this._initialState.session.state; + + this._previousSessionCrashed = + !stateFlagPresent || + this._initialState.session.state == STATE_RUNNING_STR; + } + + // Report shutdown success via telemetry. Shortcoming here are + // being-killed-by-OS-shutdown-logic, shutdown freezing after + // session restore was written, etc. + Services.telemetry + .getHistogramById("SHUTDOWN_OK") + .add(!this._previousSessionCrashed); + + Services.obs.addObserver(this, "sessionstore-windows-restored", true); + + if (this.sessionType == this.NO_SESSION) { + this._initialState = null; // Reset the state. + } else { + Services.obs.addObserver(this, "browser:purge-session-history", true); + } + + // We're ready. Notify everyone else. + Services.obs.notifyObservers(null, "sessionstore-state-finalized"); + + gOnceInitializedDeferred.resolve(); + }); + }, + + /** + * Handle notifications + */ + observe(subject, topic, data) { + switch (topic) { + case "sessionstore-windows-restored": + Services.obs.removeObserver(this, "sessionstore-windows-restored"); + // Free _initialState after nsSessionStore is done with it. + this._initialState = null; + this._didRestore = true; + break; + case "browser:purge-session-history": + Services.obs.removeObserver(this, "browser:purge-session-history"); + // Reset all state on sanitization. + this._sessionType = this.NO_SESSION; + break; + } + }, + + /* ........ Public API ................*/ + + get onceInitialized() { + return gOnceInitializedDeferred.promise; + }, + + /** + * Get the session state as a jsval + */ + get state() { + return this._initialState; + }, + + /** + * Determines whether automatic session restoration is enabled for this + * launch of the browser. This does not include crash restoration. In + * particular, if session restore is configured to restore only in case of + * crash, this method returns false. + * @returns bool + */ + isAutomaticRestoreEnabled() { + if (this._resumeSessionEnabled === null) { + this._resumeSessionEnabled = + !lazy.PrivateBrowsingUtils.permanentPrivateBrowsing && + (Services.prefs.getBoolPref( + "browser.sessionstore.resume_session_once" + ) || + Services.prefs.getIntPref("browser.startup.page") == + BROWSER_STARTUP_RESUME_SESSION); + } + + return this._resumeSessionEnabled; + }, + + /** + * Determines whether there is a pending session restore. + * @returns bool + */ + willRestore() { + return ( + this.sessionType == this.RECOVER_SESSION || + this.sessionType == this.RESUME_SESSION + ); + }, + + /** + * Determines whether there is a pending session restore and if that will refer + * back to a crash. + * @returns bool + */ + willRestoreAsCrashed() { + return this.sessionType == this.RECOVER_SESSION; + }, + + /** + * Returns a boolean or a promise that resolves to a boolean, indicating + * whether we will restore a session that ends up replacing the homepage. + * True guarantees that we'll restore a session; false means that we + * /probably/ won't do so. + * The browser uses this to avoid unnecessarily loading the homepage when + * restoring a session. + */ + get willOverrideHomepage() { + // If the session file hasn't been read yet and resuming the session isn't + // enabled via prefs, go ahead and load the homepage. We may still replace + // it when recovering from a crash, which we'll only know after reading the + // session file, but waiting for that would delay loading the homepage in + // the non-crash case. + if (!this._initialState && !this.isAutomaticRestoreEnabled()) { + return false; + } + // If we've already restored the session, we won't override again. + if (this._didRestore) { + return false; + } + + return new Promise(resolve => { + this.onceInitialized.then(() => { + // If there are valid windows with not only pinned tabs, signal that we + // will override the default homepage by restoring a session. + resolve( + this.willRestore() && + this._initialState && + this._initialState.windows && + (!this.willRestoreAsCrashed() + ? this._initialState.windows.filter(w => !w._maybeDontRestoreTabs) + : this._initialState.windows + ).some(w => w.tabs.some(t => !t.pinned)) + ); + }); + }); + }, + + /** + * Get the type of pending session store, if any. + */ + get sessionType() { + if (this._sessionType === null) { + let resumeFromCrash = Services.prefs.getBoolPref( + "browser.sessionstore.resume_from_crash" + ); + // Set the startup type. + if (this.isAutomaticRestoreEnabled()) { + this._sessionType = this.RESUME_SESSION; + } else if (this._previousSessionCrashed && resumeFromCrash) { + this._sessionType = this.RECOVER_SESSION; + } else if (this._initialState) { + this._sessionType = this.DEFER_SESSION; + } else { + this._sessionType = this.NO_SESSION; + } + } + + return this._sessionType; + }, + + /** + * Get whether the previous session crashed. + */ + get previousSessionCrashed() { + return this._previousSessionCrashed; + }, + + resetForTest() { + this._resumeSessionEnabled = null; + this._sessionType = null; + }, + + QueryInterface: ChromeUtils.generateQI([ + "nsIObserver", + "nsISupportsWeakReference", + ]), +}; |