Issue #303 Part 1: Move basilisk files from /browser to /application/basilisk

application/basilisk/components/sessionstore/SessionSaver.jsm

@@ -0,0 +1,264 @@
+/* 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/. */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = ["SessionSaver"];
+
+const Cu = Components.utils;
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+
+Cu.import("resource://gre/modules/Timer.jsm", this);
+Cu.import("resource://gre/modules/Services.jsm", this);
+Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
+Cu.import("resource://gre/modules/TelemetryStopwatch.jsm", this);
+
+XPCOMUtils.defineLazyModuleGetter(this, "AppConstants",
+  "resource://gre/modules/AppConstants.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "console",
+  "resource://gre/modules/Console.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "PrivacyFilter",
+  "resource:///modules/sessionstore/PrivacyFilter.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "RunState",
+  "resource:///modules/sessionstore/RunState.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "SessionStore",
+  "resource:///modules/sessionstore/SessionStore.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "SessionFile",
+  "resource:///modules/sessionstore/SessionFile.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "PrivateBrowsingUtils",
+  "resource://gre/modules/PrivateBrowsingUtils.jsm");
+
+// Minimal interval between two save operations (in milliseconds).
+XPCOMUtils.defineLazyGetter(this, "gInterval", function () {
+  const PREF = "browser.sessionstore.interval";
+
+  // Observer that updates the cached value when the preference changes.
+  Services.prefs.addObserver(PREF, () => {
+    this.gInterval = Services.prefs.getIntPref(PREF);
+
+    // Cancel any pending runs and call runDelayed() with
+    // zero to apply the newly configured interval.
+    SessionSaverInternal.cancel();
+    SessionSaverInternal.runDelayed(0);
+  }, false);
+
+  return Services.prefs.getIntPref(PREF);
+});
+
+// Notify observers about a given topic with a given subject.
+function notify(subject, topic) {
+  Services.obs.notifyObservers(subject, topic, "");
+}
+
+// TelemetryStopwatch helper functions.
+function stopWatch(method) {
+  return function (...histograms) {
+    for (let hist of histograms) {
+      TelemetryStopwatch[method]("FX_SESSION_RESTORE_" + hist);
+    }
+  };
+}
+
+var stopWatchStart = stopWatch("start");
+var stopWatchCancel = stopWatch("cancel");
+var stopWatchFinish = stopWatch("finish");
+
+/**
+ * The external API implemented by the SessionSaver module.
+ */
+this.SessionSaver = Object.freeze({
+  /**
+   * Immediately saves the current session to disk.
+   */
+  run: function () {
+    return SessionSaverInternal.run();
+  },
+
+  /**
+   * Saves the current session to disk delayed by a given amount of time. Should
+   * another delayed run be scheduled already, we will ignore the given delay
+   * and state saving may occur a little earlier.
+   */
+  runDelayed: function () {
+    SessionSaverInternal.runDelayed();
+  },
+
+  /**
+   * Sets the last save time to the current time. This will cause us to wait for
+   * at least the configured interval when runDelayed() is called next.
+   */
+  updateLastSaveTime: function () {
+    SessionSaverInternal.updateLastSaveTime();
+  },
+
+  /**
+   * Cancels all pending session saves.
+   */
+  cancel: function () {
+    SessionSaverInternal.cancel();
+  }
+});
+
+/**
+ * The internal API.
+ */
+var SessionSaverInternal = {
+  /**
+   * The timeout ID referencing an active timer for a delayed save. When no
+   * save is pending, this is null.
+   */
+  _timeoutID: null,
+
+  /**
+   * A timestamp that keeps track of when we saved the session last. We will
+   * this to determine the correct interval between delayed saves to not deceed
+   * the configured session write interval.
+   */
+  _lastSaveTime: 0,
+
+  /**
+   * Immediately saves the current session to disk.
+   */
+  run: function () {
+    return this._saveState(true /* force-update all windows */);
+  },
+
+  /**
+   * Saves the current session to disk delayed by a given amount of time. Should
+   * another delayed run be scheduled already, we will ignore the given delay
+   * and state saving may occur a little earlier.
+   *
+   * @param delay (optional)
+   *        The minimum delay in milliseconds to wait for until we collect and
+   *        save the current session.
+   */
+  runDelayed: function (delay = 2000) {
+    // Bail out if there's a pending run.
+    if (this._timeoutID) {
+      return;
+    }
+
+    // Interval until the next disk operation is allowed.
+    delay = Math.max(this._lastSaveTime + gInterval - Date.now(), delay, 0);
+
+    // Schedule a state save.
+    this._timeoutID = setTimeout(() => this._saveStateAsync(), delay);
+  },
+
+  /**
+   * Sets the last save time to the current time. This will cause us to wait for
+   * at least the configured interval when runDelayed() is called next.
+   */
+  updateLastSaveTime: function () {
+    this._lastSaveTime = Date.now();
+  },
+
+  /**
+   * Cancels all pending session saves.
+   */
+  cancel: function () {
+    clearTimeout(this._timeoutID);
+    this._timeoutID = null;
+  },
+
+  /**
+   * Saves the current session state. Collects data and writes to disk.
+   *
+   * @param forceUpdateAllWindows (optional)
+   *        Forces us to recollect data for all windows and will bypass and
+   *        update the corresponding caches.
+   */
+  _saveState: function (forceUpdateAllWindows = false) {
+    // Cancel any pending timeouts.
+    this.cancel();
+
+    if (PrivateBrowsingUtils.permanentPrivateBrowsing) {
+      // Don't save (or even collect) anything in permanent private
+      // browsing mode
+
+      this.updateLastSaveTime();
+      return Promise.resolve();
+    }
+
+    stopWatchStart("COLLECT_DATA_MS", "COLLECT_DATA_LONGEST_OP_MS");
+    let state = SessionStore.getCurrentState(forceUpdateAllWindows);
+    PrivacyFilter.filterPrivateWindowsAndTabs(state);
+
+    // Make sure that we keep the previous session if we started with a single
+    // private window and no non-private windows have been opened, yet.
+    if (state.deferredInitialState) {
+      state.windows = state.deferredInitialState.windows || [];
+      delete state.deferredInitialState;
+    }
+
+    if (AppConstants.platform != "macosx") {
+      // We want to restore closed windows that are marked with _shouldRestore.
+      // We're doing this here because we want to control this only when saving
+      // the file.
+      while (state._closedWindows.length) {
+        let i = state._closedWindows.length - 1;
+
+        if (!state._closedWindows[i]._shouldRestore) {
+          // We only need to go until _shouldRestore
+          // is falsy since we're going in reverse.
+          break;
+        }
+
+        delete state._closedWindows[i]._shouldRestore;
+        state.windows.unshift(state._closedWindows.pop());
+      }
+    }
+
+    // Clear all cookies on clean shutdown according to user preferences
+    if (RunState.isClosing) {
+      let expireCookies = Services.prefs.getIntPref("network.cookie.lifetimePolicy") ==
+                          Services.cookies.QueryInterface(Ci.nsICookieService).ACCEPT_SESSION;
+      let sanitizeCookies = Services.prefs.getBoolPref("privacy.sanitize.sanitizeOnShutdown") &&
+                            Services.prefs.getBoolPref("privacy.clearOnShutdown.cookies");
+      let restart = Services.prefs.getBoolPref("browser.sessionstore.resume_session_once");
+      // Don't clear cookies when restarting
+      if ((expireCookies || sanitizeCookies) && !restart) {
+        for (let window of state.windows) {
+          delete window.cookies;
+        }
+      }
+    }
+
+    stopWatchFinish("COLLECT_DATA_MS", "COLLECT_DATA_LONGEST_OP_MS");
+    return this._writeState(state);
+  },
+
+  /**
+   * Saves the current session state. Collects data asynchronously and calls
+   * _saveState() to collect data again (with a cache hit rate of hopefully
+   * 100%) and write to disk afterwards.
+   */
+  _saveStateAsync: function () {
+    // Allow scheduling delayed saves again.
+    this._timeoutID = null;
+
+    // Write to disk.
+    this._saveState();
+  },
+
+  /**
+   * Write the given state object to disk.
+   */
+  _writeState: function (state) {
+    // We update the time stamp before writing so that we don't write again
+    // too soon, if saving is requested before the write completes. Without
+    // this update we may save repeatedly if actions cause a runDelayed
+    // before writing has completed. See Bug 902280
+    this.updateLastSaveTime();
+
+    // Write (atomically) to a session file, using a tmp file. Once the session
+    // file is successfully updated, save the time stamp of the last save and
+    // notify the observers.
+    return SessionFile.write(state).then(() => {
+      this.updateLastSaveTime();
+      notify(null, "sessionstore-state-write-complete");
+    }, console.error);
+  },
+};