michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: const Cc = Components.classes;
michael@0: const Ci = Components.interfaces;
michael@0: const Cu = Components.utils;
michael@0: 
michael@0: Cu.import("resource://gre/modules/Services.jsm");
michael@0: Cu.import("resource://gre/modules/FileUtils.jsm");
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["FreeSpaceWatcher"];
michael@0: 
michael@0: function debug(aMsg) {
michael@0:   //dump("-*-*- FreeSpaceWatcher.jsm : " + aMsg + "\n");
michael@0: }
michael@0: 
michael@0: // Polling delay for free space, in ms.
michael@0: const DEFAULT_WATCHER_DELAY = 1000;
michael@0: 
michael@0: this.FreeSpaceWatcher = {
michael@0:   timers: {},
michael@0:   id: 0,
michael@0: 
michael@0:   /**
michael@0:    * This function  will call aOnStatusChange
michael@0:    * each time the free space for apps crosses aThreshold, checking
michael@0:    * every aDelay milliseconds, or every second by default.
michael@0:    * aOnStatusChange is called with either "free" or "full" and will
michael@0:    * always be called at least one to get the initial status.
michael@0:    * @param aThreshold      The amount of space in bytes to watch for.
michael@0:    * @param aOnStatusChange The function called when the state changes.
michael@0:    * @param aDelay          How often (in ms) we check free space. Defaults
michael@0:    *                        to DEFAULT_WATCHER_DELAY.
michael@0:    * @return                An opaque value to use with stop().
michael@0:    */
michael@0:   create: function spaceWatcher_create(aThreshold, aOnStatusChange, aDelay) {
michael@0:     let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
michael@0:     debug("Creating new FreeSpaceWatcher");
michael@0:     let callback = {
michael@0:       currentStatus: null,
michael@0:       notify: function(aTimer) {
michael@0:         try {
michael@0:           let checkFreeSpace = function (freeBytes) {
michael@0:             debug("Free bytes: " + freeBytes);
michael@0:             let newStatus = freeBytes > aThreshold;
michael@0:             if (newStatus != callback.currentStatus) {
michael@0:               debug("New status: " + (newStatus ? "free" : "full"));
michael@0:               aOnStatusChange(newStatus ? "free" : "full");
michael@0:               callback.currentStatus = newStatus;
michael@0:             }
michael@0:           };
michael@0: 
michael@0:           let navigator = Services.wm.getMostRecentWindow("navigator:browser")
michael@0:                                   .navigator;
michael@0:           let deviceStorage = null;
michael@0: 
michael@0:           if (navigator.getDeviceStorage) {
michael@0:             deviceStorage = navigator.getDeviceStorage("apps");
michael@0:           }
michael@0: 
michael@0:           if (deviceStorage) {
michael@0:             let req = deviceStorage.freeSpace();
michael@0:             req.onsuccess = req.onerror = function statResult(e) {
michael@0:               if (!e.target.result) {
michael@0:                 return;
michael@0:               }
michael@0: 
michael@0:               let freeBytes = e.target.result;
michael@0:               checkFreeSpace(freeBytes);
michael@0:             }
michael@0:           } else {
michael@0:             // deviceStorage isn't available, so use the webappsDir instead.
michael@0:             // This needs to be moved from a hardcoded string to DIRECTORY_NAME
michael@0:             // in AppsUtils. See bug 852685.
michael@0:             let dir = FileUtils.getDir("webappsDir", ["webapps"], true, true);
michael@0:             let freeBytes;
michael@0:             try {
michael@0:               freeBytes = dir.diskSpaceAvailable;
michael@0:             } catch(e) {
michael@0:               // If disk space information isn't available, we should assume
michael@0:               // that there is enough free space, and that we'll fail when
michael@0:               // we actually run out of disk space.
michael@0:               callback.currentStatus = true;
michael@0:             }
michael@0:             if (freeBytes) {
michael@0:               // We have disk space information. Call this here so that
michael@0:               // any exceptions are caught in the outer catch block.
michael@0:               checkFreeSpace(freeBytes);
michael@0:             }
michael@0:           }
michael@0:         } catch(e) {
michael@0:           // If the aOnStatusChange callback has errored we'll end up here.
michael@0:           debug(e);
michael@0:         }
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     timer.initWithCallback(callback, aDelay || DEFAULT_WATCHER_DELAY,
michael@0:                            Ci.nsITimer.TYPE_REPEATING_SLACK);
michael@0:     let id = "timer-" + this.id++;
michael@0:     this.timers[id] = timer;
michael@0:     return id;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * This function stops a running watcher.
michael@0:    * @param aId The opaque timer id returned by create().
michael@0:    */
michael@0:   stop: function spaceWatcher_stop(aId) {
michael@0:     if (this.timers[aId]) {
michael@0:       this.timers[aId].cancel();
michael@0:       delete this.timers[aId];
michael@0:     }
michael@0:   }
michael@0: }