gecko-dev/browser/base/content/sanitize.js

// -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
/* 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/. */

Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
Components.utils.import("resource://gre/modules/Services.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "AppConstants",
                                  "resource://gre/modules/AppConstants.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "PlacesUtils",
                                  "resource://gre/modules/PlacesUtils.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "FormHistory",
                                  "resource://gre/modules/FormHistory.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Downloads",
                                  "resource://gre/modules/Downloads.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Promise",
                                  "resource://gre/modules/Promise.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Task",
                                  "resource://gre/modules/Task.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "DownloadsCommon",
                                  "resource:///modules/DownloadsCommon.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "TelemetryStopwatch",
                                  "resource://gre/modules/TelemetryStopwatch.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "console",
                                  "resource://gre/modules/Console.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Preferences",
                                  "resource://gre/modules/Preferences.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "setTimeout",
                                  "resource://gre/modules/Timer.jsm");

/**
 * A number of iterations after which to yield time back
 * to the system.
 */
const YIELD_PERIOD = 10;

function Sanitizer() {
}
Sanitizer.prototype = {
  // warning to the caller: this one may raise an exception (e.g. bug #265028)
  clearItem: function (aItemName)
  {
    this.items[aItemName].clear();
  },

  prefDomain: "",

  getNameFromPreference: function (aPreferenceName)
  {
    return aPreferenceName.substr(this.prefDomain.length);
  },

  /**
   * Deletes privacy sensitive data in a batch, according to user preferences.
   * Returns a promise which is resolved if no errors occurred.  If an error
   * occurs, a message is reported to the console and all other items are still
   * cleared before the promise is finally rejected.
   *
   * If the consumer specifies the (optional) array parameter, only those
   * items get cleared (irrespective of the preference settings)
   */
  sanitize: Task.async(function*(aItemsToClear = null) {
    let progress = {};
    let promise = this._sanitize(aItemsToClear, progress);

    //
    // Depending on preferences, the sanitizer may perform asynchronous
    // work before it starts cleaning up the Places database (e.g. closing
    // windows). We need to make sure that the connection to that database
    // hasn't been closed by the time we use it.
    //
    let shutdownClient = Cc["@mozilla.org/browser/nav-history-service;1"]
       .getService(Ci.nsPIPlacesDatabase)
       .shutdownClient
       .jsclient;

    shutdownClient.addBlocker("sanitize.js: Sanitize",
      promise,
      {
        fetchState: () => {
          return { progress };
        }
      }
    );
    try {
      yield promise;
    } finally {
      Services.obs.notifyObservers(null, "sanitizer-sanitization-complete", "");
    }
  }),

  _sanitize: Task.async(function*(aItemsToClear, progress = {}) {
    let seenError = false;
    let itemsToClear;
    if (Array.isArray(aItemsToClear)) {
      // Shallow copy the array, as we are going to modify
      // it in place later.
      itemsToClear = [...aItemsToClear];
    } else {
      let branch = Services.prefs.getBranch(this.prefDomain);
      itemsToClear = Object.keys(this.items).filter(itemName => {
        try {
          return branch.getBoolPref(itemName);
        } catch (ex) {
          return false;
        }
      });
    }

    // Store the list of items to clear, in case we are killed before we
    // get a chance to complete.
    Preferences.set(Sanitizer.PREF_SANITIZE_IN_PROGRESS, JSON.stringify(itemsToClear));

    // Store the list of items to clear, for debugging/forensics purposes
    for (let k of itemsToClear) {
      progress[k] = "ready";
    }

    // Ensure open windows get cleared first, if they're in our list, so that they don't stick
    // around in the recently closed windows list, and so we can cancel the whole thing
    // if the user selects to keep a window open from a beforeunload prompt.
    let openWindowsIndex = itemsToClear.indexOf("openWindows");
    if (openWindowsIndex != -1) {
      itemsToClear.splice(openWindowsIndex, 1);
      yield this.items.openWindows.clear();
      progress.openWindows = "cleared";
    }

    // Cache the range of times to clear
    let range = null;
    // If we ignore timespan, clear everything,
    // otherwise, pick a range.
    if (!this.ignoreTimespan) {
      range = this.range || Sanitizer.getClearRange();
    }

    for (let itemName of itemsToClear) {
      let item = this.items[itemName];
      if (!("clear" in item)) {
        progress[itemName] = "`clear` not in item";
        continue;
      }
      item.range = range;
      // Some of these clear() may raise exceptions (see bug #265028)
      // to sanitize as much as possible, we catch and store them,
      // rather than fail fast.
      // Callers should check returned errors and give user feedback
      // about items that could not be sanitized
      let refObj = {};
      try {
        TelemetryStopwatch.start("FX_SANITIZE_TOTAL", refObj);
        yield item.clear();
        progress[itemName] = "cleared";
      } catch(er) {
        progress[itemName] = "failed";
        seenError = true;
        console.error("Error sanitizing " + itemName, er);
      } finally {
        TelemetryStopwatch.finish("FX_SANITIZE_TOTAL", refObj);
      }
    }

    // Sanitization is complete.
    Preferences.reset(Sanitizer.PREF_SANITIZE_IN_PROGRESS);
    progress = {};
    if (seenError) {
      throw new Error("Error sanitizing");
    }
  }),

  // Time span only makes sense in certain cases.  Consumers who want
  // to only clear some private data can opt in by setting this to false,
  // and can optionally specify a specific range.  If timespan is not ignored,
  // and range is not set, sanitize() will use the value of the timespan
  // pref to determine a range
  ignoreTimespan : true,
  range : null,

  items: {
    cache: {
      clear: function ()
      {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_CACHE", refObj);

        var cache = Cc["@mozilla.org/netwerk/cache-storage-service;1"].
                    getService(Ci.nsICacheStorageService);
        try {
          // Cache doesn't consult timespan, nor does it have the
          // facility for timespan-based eviction.  Wipe it.
          cache.clear();
        } catch(er) {}

        var imageCache = Cc["@mozilla.org/image/tools;1"].
                         getService(Ci.imgITools).getImgCacheForDocument(null);
        try {
          imageCache.clearCache(false); // true=chrome, false=content
        } catch(er) {}

        TelemetryStopwatch.finish("FX_SANITIZE_CACHE", refObj);
      }
    },

    cookies: {
      clear: Task.async(function* ()
      {
        let yieldCounter = 0;
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_COOKIES", refObj);
        TelemetryStopwatch.start("FX_SANITIZE_COOKIES_2", refObj);

        var cookieMgr = Components.classes["@mozilla.org/cookiemanager;1"]
                                  .getService(Ci.nsICookieManager);
        if (this.range) {
          // Iterate through the cookies and delete any created after our cutoff.
          var cookiesEnum = cookieMgr.enumerator;
          while (cookiesEnum.hasMoreElements()) {
            var cookie = cookiesEnum.getNext().QueryInterface(Ci.nsICookie2);

            if (cookie.creationTime > this.range[0]) {
              // This cookie was created after our cutoff, clear it
              cookieMgr.remove(cookie.host, cookie.name, cookie.path, false);

              if (++yieldCounter % YIELD_PERIOD == 0) {
                yield new Promise(resolve => setTimeout(resolve, 0)); // Don't block the main thread too long
              }
            }
          }
        }
        else {
          // Remove everything
          cookieMgr.removeAll();
          yield new Promise(resolve => setTimeout(resolve, 0)); // Don't block the main thread too long
        }
        TelemetryStopwatch.finish("FX_SANITIZE_COOKIES_2", refObj);

        // Clear deviceIds. Done asynchronously (returns before complete).
        let mediaMgr = Components.classes["@mozilla.org/mediaManagerService;1"]
                                 .getService(Ci.nsIMediaManagerService);
        mediaMgr.sanitizeDeviceIds(this.range && this.range[0]);

        // Clear plugin data.
        TelemetryStopwatch.start("FX_SANITIZE_PLUGINS", refObj);
        yield this.promiseClearPluginCookies();
        TelemetryStopwatch.finish("FX_SANITIZE_PLUGINS", refObj);
        TelemetryStopwatch.finish("FX_SANITIZE_COOKIES", refObj);
      }),

      promiseClearPluginCookies: Task.async(function*() {
        const phInterface = Ci.nsIPluginHost;
        const FLAG_CLEAR_ALL = phInterface.FLAG_CLEAR_ALL;
        let ph = Cc["@mozilla.org/plugin/host;1"].getService(phInterface);

        // Determine age range in seconds. (-1 means clear all.) We don't know
        // that this.range[1] is actually now, so we compute age range based
        // on the lower bound. If this.range results in a negative age, do
        // nothing.
        let age = this.range ? (Date.now() / 1000 - this.range[0] / 1000000) : -1;
        if (!this.range || age >= 0) {
          let tags = ph.getPluginTags();
          for (let tag of tags) {
            try {
              let rv = yield new Promise(resolve =>
                ph.clearSiteData(tag, null, FLAG_CLEAR_ALL, age, resolve)
              );
              // If the plugin doesn't support clearing by age, clear everything.
              if (rv == Components.results.NS_ERROR_PLUGIN_TIME_RANGE_NOT_SUPPORTED) {
                yield new Promise(resolve =>
                  ph.clearSiteData(tag, null, FLAG_CLEAR_ALL, -1, resolve)
                );
              }
            } catch (ex) {
              // Ignore errors from plug-ins
            }
          }
        }
      })
    },

    offlineApps: {
      clear: function ()
      {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_OFFLINEAPPS", refObj);
        Components.utils.import("resource:///modules/offlineAppCache.jsm");
        OfflineAppCacheHelper.clear();
        TelemetryStopwatch.finish("FX_SANITIZE_OFFLINEAPPS", refObj);
      }
    },

    history: {
      clear: Task.async(function* ()
      {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_HISTORY", refObj);
        try {
          if (this.range) {
            yield PlacesUtils.history.removeVisitsByFilter({
              beginDate: new Date(this.range[0] / 1000),
              endDate: new Date(this.range[1] / 1000)
            });
          } else {
            // Remove everything.
            yield PlacesUtils.history.clear();
          }

          try {
            let clearStartingTime = this.range ? String(this.range[0]) : "";
            Services.obs.notifyObservers(null, "browser:purge-session-history", clearStartingTime);
          } catch (e) { }

          try {
            let predictor = Components.classes["@mozilla.org/network/predictor;1"]
                                      .getService(Components.interfaces.nsINetworkPredictor);
            predictor.reset();
          } catch (e) {
            console.error("Error while resetting the predictor", e);
          }
        } finally {
          TelemetryStopwatch.finish("FX_SANITIZE_HISTORY", refObj);
        }
      })
    },

    formdata: {
      clear: function ()
      {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_FORMDATA", refObj);

        // Clear undo history of all searchBars
        var windowManager = Components.classes['@mozilla.org/appshell/window-mediator;1']
                                      .getService(Components.interfaces.nsIWindowMediator);
        var windows = windowManager.getEnumerator("navigator:browser");
        while (windows.hasMoreElements()) {
          let currentWindow = windows.getNext();
          let currentDocument = currentWindow.document;
          let searchBar = currentDocument.getElementById("searchbar");
          if (searchBar)
            searchBar.textbox.reset();
          let tabBrowser = currentWindow.gBrowser;
          for (let tab of tabBrowser.tabs) {
            if (tabBrowser.isFindBarInitialized(tab))
              tabBrowser.getFindBar(tab).clear();
          }
          // Clear any saved find value
          tabBrowser._lastFindValue = "";
        }

        let change = { op: "remove" };
        if (this.range) {
          [ change.firstUsedStart, change.firstUsedEnd ] = this.range;
        }
        FormHistory.update(change);

        TelemetryStopwatch.finish("FX_SANITIZE_FORMDATA", refObj);
      }
    },

    downloads: {
      clear: function ()
      {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_DOWNLOADS", refObj);
        Task.spawn(function*() {
          let filterByTime = null;
          if (this.range) {
            // Convert microseconds back to milliseconds for date comparisons.
            let rangeBeginMs = this.range[0] / 1000;
            let rangeEndMs = this.range[1] / 1000;
            filterByTime = download => download.startTime >= rangeBeginMs &&
                                       download.startTime <= rangeEndMs;
          }

          // Clear all completed/cancelled downloads
          let list = yield Downloads.getList(Downloads.ALL);
          list.removeFinished(filterByTime);
          TelemetryStopwatch.finish("FX_SANITIZE_DOWNLOADS", refObj);
        }.bind(this)).then(null, error => {
          TelemetryStopwatch.finish("FX_SANITIZE_DOWNLOADS", refObj);
          Components.utils.reportError(error);
        });
      }
    },

    sessions: {
      clear: function ()
      {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_SESSIONS", refObj);

        // clear all auth tokens
        var sdr = Components.classes["@mozilla.org/security/sdr;1"]
                            .getService(Components.interfaces.nsISecretDecoderRing);
        sdr.logoutAndTeardown();

        // clear FTP and plain HTTP auth sessions
        var os = Components.classes["@mozilla.org/observer-service;1"]
                           .getService(Components.interfaces.nsIObserverService);
        os.notifyObservers(null, "net:clear-active-logins", null);

        TelemetryStopwatch.finish("FX_SANITIZE_SESSIONS", refObj);
      }
    },

    siteSettings: {
      clear: function ()
      {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_SITESETTINGS", refObj);

        // Clear site-specific permissions like "Allow this site to open popups"
        // we ignore the "end" range and hope it is now() - none of the
        // interfaces used here support a true range anyway.
        let startDateMS = this.range == null ? null : this.range[0] / 1000;
        var pm = Components.classes["@mozilla.org/permissionmanager;1"]
                           .getService(Components.interfaces.nsIPermissionManager);
        if (startDateMS == null) {
          pm.removeAll();
        } else {
          pm.removeAllSince(startDateMS);
        }

        // Clear site-specific settings like page-zoom level
        var cps = Components.classes["@mozilla.org/content-pref/service;1"]
                            .getService(Components.interfaces.nsIContentPrefService2);
        if (startDateMS == null) {
          cps.removeAllDomains(null);
        } else {
          cps.removeAllDomainsSince(startDateMS, null);
        }

        // Clear "Never remember passwords for this site", which is not handled by
        // the permission manager
        // (Note the login manager doesn't support date ranges yet, and bug
        //  1058438 is calling for loginSaving stuff to end up in the
        // permission manager)
        var pwmgr = Components.classes["@mozilla.org/login-manager;1"]
                              .getService(Components.interfaces.nsILoginManager);
        var hosts = pwmgr.getAllDisabledHosts();
        for (var host of hosts) {
          pwmgr.setLoginSavingEnabled(host, true);
        }

        // Clear site security settings - no support for ranges in this
        // interface either, so we clearAll().
        var sss = Cc["@mozilla.org/ssservice;1"]
                    .getService(Ci.nsISiteSecurityService);
        sss.clearAll();

        // Clear all push notification subscriptions
        try {
          var push = Cc["@mozilla.org/push/Service;1"]
                       .getService(Ci.nsIPushService);
          push.clearForDomain("*", status => {
            if (!Components.isSuccessCode(status)) {
              dump("Error clearing Web Push data: " + status + "\n");
            }
          });
        } catch (e) {
          dump("Web Push may not be available.\n");
        }

        TelemetryStopwatch.finish("FX_SANITIZE_SITESETTINGS", refObj);
      }
    },

    openWindows: {
      privateStateForNewWindow: "non-private",
      _canCloseWindow: function(aWindow) {
        if (aWindow.CanCloseWindow()) {
          // We already showed PermitUnload for the window, so let's
          // make sure we don't do it again when we actually close the
          // window.
          aWindow.skipNextCanClose = true;
          return true;
        }
      },
      _resetAllWindowClosures: function(aWindowList) {
        for (let win of aWindowList) {
          win.skipNextCanClose = false;
        }
      },
      clear: Task.async(function*() {
        // NB: this closes all *browser* windows, not other windows like the library, about window,
        // browser console, etc.

        // Keep track of the time in case we get stuck in la-la-land because of onbeforeunload
        // dialogs
        let existingWindow = Services.appShell.hiddenDOMWindow;
        let startDate = existingWindow.performance.now();

        // First check if all these windows are OK with being closed:
        let windowEnumerator = Services.wm.getEnumerator("navigator:browser");
        let windowList = [];
        while (windowEnumerator.hasMoreElements()) {
          let someWin = windowEnumerator.getNext();
          windowList.push(someWin);
          // If someone says "no" to a beforeunload prompt, we abort here:
          if (!this._canCloseWindow(someWin)) {
            this._resetAllWindowClosures(windowList);
            throw new Error("Sanitize could not close windows: cancelled by user");
          }

          // ...however, beforeunload prompts spin the event loop, and so the code here won't get
          // hit until the prompt has been dismissed. If more than 1 minute has elapsed since we
          // started prompting, stop, because the user might not even remember initiating the
          // 'forget', and the timespans will be all wrong by now anyway:
          if (existingWindow.performance.now() > (startDate + 60 * 1000)) {
            this._resetAllWindowClosures(windowList);
            throw new Error("Sanitize could not close windows: timeout");
          }
        }

        // If/once we get here, we should actually be able to close all windows.

        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_OPENWINDOWS", refObj);

        // First create a new window. We do this first so that on non-mac, we don't
        // accidentally close the app by closing all the windows.
        let handler = Cc["@mozilla.org/browser/clh;1"].getService(Ci.nsIBrowserHandler);
        let defaultArgs = handler.defaultArgs;
        let features = "chrome,all,dialog=no," + this.privateStateForNewWindow;
        let newWindow = existingWindow.openDialog("chrome://browser/content/", "_blank",
                                                  features, defaultArgs);

        let onFullScreen = null;
        if (AppConstants.platform == "macosx") {
          onFullScreen = function(e) {
            newWindow.removeEventListener("fullscreen", onFullScreen);
            let docEl = newWindow.document.documentElement;
            let sizemode = docEl.getAttribute("sizemode");
            if (!newWindow.fullScreen && sizemode == "fullscreen") {
              docEl.setAttribute("sizemode", "normal");
              e.preventDefault();
              e.stopPropagation();
              return false;
            }
          }
          newWindow.addEventListener("fullscreen", onFullScreen);
        }

        let promiseReady = new Promise(resolve => {
          // Window creation and destruction is asynchronous. We need to wait
          // until all existing windows are fully closed, and the new window is
          // fully open, before continuing. Otherwise the rest of the sanitizer
          // could run too early (and miss new cookies being set when a page
          // closes) and/or run too late (and not have a fully-formed window yet
          // in existence). See bug 1088137.
          let newWindowOpened = false;
          let onWindowOpened = function(subject, topic, data) {
            if (subject != newWindow)
              return;

            Services.obs.removeObserver(onWindowOpened, "browser-delayed-startup-finished");
            if (AppConstants.platform == "macosx") {
              newWindow.removeEventListener("fullscreen", onFullScreen);
            }
            newWindowOpened = true;
            // If we're the last thing to happen, invoke callback.
            if (numWindowsClosing == 0) {
              TelemetryStopwatch.finish("FX_SANITIZE_OPENWINDOWS", refObj);
              resolve();
            }
          }

          let numWindowsClosing = windowList.length;
          let onWindowClosed = function() {
            numWindowsClosing--;
            if (numWindowsClosing == 0) {
              Services.obs.removeObserver(onWindowClosed, "xul-window-destroyed");
              // If we're the last thing to happen, invoke callback.
              if (newWindowOpened) {
                TelemetryStopwatch.finish("FX_SANITIZE_OPENWINDOWS", refObj);
                resolve();
              }
            }
          }
          Services.obs.addObserver(onWindowOpened, "browser-delayed-startup-finished", false);
          Services.obs.addObserver(onWindowClosed, "xul-window-destroyed", false);
        });

        // Start the process of closing windows
        while (windowList.length) {
          windowList.pop().close();
        }
        newWindow.focus();
        yield promiseReady;
      })
    },
  }
};

// "Static" members
Sanitizer.PREF_DOMAIN = "privacy.sanitize.";
Sanitizer.PREF_SANITIZE_ON_SHUTDOWN = "privacy.sanitize.sanitizeOnShutdown";
Sanitizer.PREF_SANITIZE_IN_PROGRESS = "privacy.sanitize.sanitizeInProgress";
Sanitizer.PREF_SANITIZE_DID_SHUTDOWN = "privacy.sanitize.didShutdownSanitize";

// Time span constants corresponding to values of the privacy.sanitize.timeSpan
// pref.  Used to determine how much history to clear, for various items
Sanitizer.TIMESPAN_EVERYTHING = 0;
Sanitizer.TIMESPAN_HOUR       = 1;
Sanitizer.TIMESPAN_2HOURS     = 2;
Sanitizer.TIMESPAN_4HOURS     = 3;
Sanitizer.TIMESPAN_TODAY      = 4;
Sanitizer.TIMESPAN_5MIN       = 5;
Sanitizer.TIMESPAN_24HOURS    = 6;

// Return a 2 element array representing the start and end times,
// in the uSec-since-epoch format that PRTime likes.  If we should
// clear everything, return null.  Use ts if it is defined; otherwise
// use the timeSpan pref.
Sanitizer.getClearRange = function (ts) {
  if (ts === undefined)
    ts = Sanitizer.prefs.getIntPref("timeSpan");
  if (ts === Sanitizer.TIMESPAN_EVERYTHING)
    return null;

  // PRTime is microseconds while JS time is milliseconds
  var endDate = Date.now() * 1000;
  switch (ts) {
    case Sanitizer.TIMESPAN_5MIN :
      var startDate = endDate - 300000000; // 5*60*1000000
      break;
    case Sanitizer.TIMESPAN_HOUR :
      startDate = endDate - 3600000000; // 1*60*60*1000000
      break;
    case Sanitizer.TIMESPAN_2HOURS :
      startDate = endDate - 7200000000; // 2*60*60*1000000
      break;
    case Sanitizer.TIMESPAN_4HOURS :
      startDate = endDate - 14400000000; // 4*60*60*1000000
      break;
    case Sanitizer.TIMESPAN_TODAY :
      var d = new Date();  // Start with today
      d.setHours(0);      // zero us back to midnight...
      d.setMinutes(0);
      d.setSeconds(0);
      startDate = d.valueOf() * 1000; // convert to epoch usec
      break;
    case Sanitizer.TIMESPAN_24HOURS :
      startDate = endDate - 86400000000; // 24*60*60*1000000
      break;
    default:
      throw "Invalid time span for clear private data: " + ts;
  }
  return [startDate, endDate];
};

Sanitizer._prefs = null;
Sanitizer.__defineGetter__("prefs", function()
{
  return Sanitizer._prefs ? Sanitizer._prefs
    : Sanitizer._prefs = Components.classes["@mozilla.org/preferences-service;1"]
                         .getService(Components.interfaces.nsIPrefService)
                         .getBranch(Sanitizer.PREF_DOMAIN);
});

// Shows sanitization UI
Sanitizer.showUI = function(aParentWindow)
{
  var ww = Components.classes["@mozilla.org/embedcomp/window-watcher;1"]
                     .getService(Components.interfaces.nsIWindowWatcher);
  let win = AppConstants.platform == "macosx" ?
    null: // make this an app-modal window on Mac
    aParentWindow;
  ww.openWindow(win,
                "chrome://browser/content/sanitize.xul",
                "Sanitize",
                "chrome,titlebar,dialog,centerscreen,modal",
                null);
};

/**
 * Deletes privacy sensitive data in a batch, optionally showing the
 * sanitize UI, according to user preferences
 */
Sanitizer.sanitize = function(aParentWindow)
{
  Sanitizer.showUI(aParentWindow);
};

Sanitizer.onStartup = Task.async(function*() {
  // Make sure that we are triggered during shutdown, at the right time.
  let shutdownClient = Cc["@mozilla.org/browser/nav-history-service;1"]
     .getService(Ci.nsPIPlacesDatabase)
     .shutdownClient
     .jsclient;

  shutdownClient.addBlocker("sanitize.js: Sanitize on shutdown",
    () => Sanitizer.onShutdown());

    // One time migration to remove support for the clear saved passwords on exit feature.
    if (!Services.prefs.getBoolPref("privacy.sanitize.migrateClearSavedPwdsOnExit")) {
      let deprecatedPref = "privacy.clearOnShutdown.passwords";
      let doUpdate = Services.prefs.prefHasUserValue(deprecatedPref) &&
                     Services.prefs.getBoolPref(deprecatedPref);
      if (doUpdate) {
        Services.logins.removeAllLogins();
        Services.prefs.setBoolPref("signon.rememberSignons", false);
      }
      Services.prefs.clearUserPref(deprecatedPref);
      Services.prefs.setBoolPref("privacy.sanitize.migrateClearSavedPwdsOnExit", true);
  }

  // Handle incomplete sanitizations
  if (Preferences.has(Sanitizer.PREF_SANITIZE_IN_PROGRESS)) {
    // Firefox crashed during sanitization.
    let s = new Sanitizer();
    let json = Preferences.get(Sanitizer.PREF_SANITIZE_IN_PROGRESS);
    let itemsToClear = JSON.parse(json);
    yield s.sanitize(itemsToClear);
  }
  if (Preferences.has(Sanitizer.PREF_SANITIZE_DID_SHUTDOWN)) {
    // Firefox crashed before having a chance to sanitize during shutdown.
    // (note that if Firefox crashed during shutdown sanitization, we
    // will hit both `if` so we will run a second double-sanitization).
    yield Sanitizer.onShutdown();
  }
});

Sanitizer.onShutdown = Task.async(function*() {
  if (!Preferences.get(Sanitizer.PREF_SANITIZE_ON_SHUTDOWN)) {
    return;
  }
  // Need to sanitize upon shutdown
  let s = new Sanitizer();
  s.prefDomain = "privacy.clearOnShutdown.";
  yield s.sanitize();
  Preferences.set(Sanitizer.PREF_SANITIZE_DID_SHUTDOWN, true);
});