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/XPCOMUtils.jsm");
michael@0: 
michael@0: XPCOMUtils.defineLazyModuleGetter(this, "FreeSpaceWatcher",
michael@0:                                   "resource://gre/modules/FreeSpaceWatcher.jsm");
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["AppDownloadManager"];
michael@0: 
michael@0: function debug(aMsg) {
michael@0:   //dump("-*-*- AppDownloadManager.jsm : " + aMsg + "\n");
michael@0: }
michael@0: 
michael@0: this.AppDownloadManager = {
michael@0:   // Minimum disk free space we want to keep, in bytes.
michael@0:   // Keep synchronized with Webapps.jsm
michael@0:   MIN_REMAINING_FREESPACE: 5 * 1024 * 1024,
michael@0: 
michael@0:   downloads: {},
michael@0:   count: 0,
michael@0:   cancelFunc: null,
michael@0:   timer: null,
michael@0: 
michael@0:   /**
michael@0:    * Registers the function called when we need to cancel a download.
michael@0:    * The function will be called with a single parameter being the
michael@0:    * manifest URL.
michael@0:    */
michael@0:   registerCancelFunction: function app_dlMgr_registerCancel(aFunction) {
michael@0:     this.cancelFunc = aFunction;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Adds a download to the list of current downloads.
michael@0:    * @param aManifestURL The manifest URL for the application being downloaded.
michael@0:    * @param aDownload    An opaque object representing the download.
michael@0:    */
michael@0:   add: function app_dlMgr_add(aManifestURL, aDownload) {
michael@0:     debug("Adding " + aManifestURL);
michael@0:     if (!(aManifestURL in this.downloads)) {
michael@0:       this.count++;
michael@0:       if (this.count == 1) {
michael@0:         this.timer = FreeSpaceWatcher.create(this.MIN_REMAINING_FREESPACE,
michael@0:                                              this._spaceWatcher.bind(this));
michael@0:       }
michael@0:     }
michael@0:     this.downloads[aManifestURL] = aDownload;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Retrieves a download from the list of current downloads.
michael@0:    * @param  aManifestURL The manifest URL for the application being retrieved.
michael@0:    * @return              The opaque object representing the download.
michael@0:    */
michael@0:   get: function app_dlMgr_get(aManifestURL) {
michael@0:     debug("Getting " + aManifestURL);
michael@0:     if (!this.downloads[aManifestURL]) {
michael@0:       return null;
michael@0:     }
michael@0:     return this.downloads[aManifestURL];
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Removes a download of the list of current downloads.
michael@0:    * @param aManifestURL The manifest URL for the application being removed.
michael@0:    */
michael@0:   remove: function app_dlMgr_remove(aManifestURL) {
michael@0:     debug("Removing " + aManifestURL);
michael@0:     if (aManifestURL in this.downloads) {
michael@0:       this.count--;
michael@0:       delete this.downloads[aManifestURL];
michael@0:       if (this.count == 0) {
michael@0:         FreeSpaceWatcher.stop(this.timer);
michael@0:       }
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Callback for the free space watcher. This will call cancel on downloads
michael@0:    * if needed.
michael@0:    */
michael@0:   _spaceWatcher: function app_dlMgr_watcher(aStatus) {
michael@0:     debug("Disk space is now " + aStatus);
michael@0:     if (aStatus == "free") {
michael@0:       // Nothing to do.
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     // We cancel all downloads, because we don't know which ones we could
michael@0:     // keep running. We can improve that later if we have better heuristics,
michael@0:     // or when we'll support pause & resume we should just pause downloads.
michael@0:     for (let url in this.downloads) {
michael@0:       this.cancelFunc(url, "INSUFFICIENT_STORAGE");
michael@0:     }
michael@0:   }
michael@0: }