The Tor Browser / file revision

 /* 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";

 const Cc = Components.classes;

 const Ci = Components.interfaces;

 const Cu = Components.utils;

 Cu.import("resource://gre/modules/Services.jsm");

 Cu.import("resource://gre/modules/FileUtils.jsm");

 this.EXPORTED_SYMBOLS = ["FreeSpaceWatcher"];

 function debug(aMsg) {

   //dump("-*-*- FreeSpaceWatcher.jsm : " + aMsg + "\n");

 }

 // Polling delay for free space, in ms.

 const DEFAULT_WATCHER_DELAY = 1000;

 this.FreeSpaceWatcher = {

   timers: {},

   id: 0,

   /**

    * This function  will call aOnStatusChange

    * each time the free space for apps crosses aThreshold, checking

    * every aDelay milliseconds, or every second by default.

    * aOnStatusChange is called with either "free" or "full" and will

    * always be called at least one to get the initial status.

    * @param aThreshold      The amount of space in bytes to watch for.

    * @param aOnStatusChange The function called when the state changes.

    * @param aDelay          How often (in ms) we check free space. Defaults

    *                        to DEFAULT_WATCHER_DELAY.

    * @return                An opaque value to use with stop().

    */

   create: function spaceWatcher_create(aThreshold, aOnStatusChange, aDelay) {

     let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);

     debug("Creating new FreeSpaceWatcher");

     let callback = {

       currentStatus: null,

       notify: function(aTimer) {

         try {

           let checkFreeSpace = function (freeBytes) {

             debug("Free bytes: " + freeBytes);

             let newStatus = freeBytes > aThreshold;

             if (newStatus != callback.currentStatus) {

               debug("New status: " + (newStatus ? "free" : "full"));

               aOnStatusChange(newStatus ? "free" : "full");

               callback.currentStatus = newStatus;

             }

           };

           let navigator = Services.wm.getMostRecentWindow("navigator:browser")

                                   .navigator;

           let deviceStorage = null;

           if (navigator.getDeviceStorage) {

             deviceStorage = navigator.getDeviceStorage("apps");

           }

           if (deviceStorage) {

             let req = deviceStorage.freeSpace();

             req.onsuccess = req.onerror = function statResult(e) {

               if (!e.target.result) {

                 return;

               }

               let freeBytes = e.target.result;

               checkFreeSpace(freeBytes);

             }

           } else {

             // deviceStorage isn't available, so use the webappsDir instead.

             // This needs to be moved from a hardcoded string to DIRECTORY_NAME

             // in AppsUtils. See bug 852685.

             let dir = FileUtils.getDir("webappsDir", ["webapps"], true, true);

             let freeBytes;

             try {

               freeBytes = dir.diskSpaceAvailable;

             } catch(e) {

               // If disk space information isn't available, we should assume

               // that there is enough free space, and that we'll fail when

               // we actually run out of disk space.

               callback.currentStatus = true;

             }

             if (freeBytes) {

               // We have disk space information. Call this here so that

               // any exceptions are caught in the outer catch block.

               checkFreeSpace(freeBytes);

             }

           }

         } catch(e) {

           // If the aOnStatusChange callback has errored we'll end up here.

           debug(e);

         }

       }

     }

     timer.initWithCallback(callback, aDelay || DEFAULT_WATCHER_DELAY,

                            Ci.nsITimer.TYPE_REPEATING_SLACK);

     let id = "timer-" + this.id++;

     this.timers[id] = timer;

     return id;

   },

   /**

    * This function stops a running watcher.

    * @param aId The opaque timer id returned by create().

    */

   stop: function spaceWatcher_stop(aId) {

     if (this.timers[aId]) {

       this.timers[aId].cancel();

       delete this.timers[aId];

     }

   }

 }