The Tor Browser: toolkit/components/jsdownloads/src/DownloadStore.jsm@6474c204b198 (annotated)

toolkit/components/jsdownloads/src/DownloadStore.jsm@6474c204b198 (annotated)

toolkit/components/jsdownloads/src/DownloadStore.jsm

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80 filetype=javascript: */
 /* 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/. */
 /**
  * Handles serialization of Download objects and persistence into a file, so
  * that the state of downloads can be restored across sessions.
  *
  * The file is stored in JSON format, without indentation.  With indentation
  * applied, the file would look like this:
  *
  * {
  *   "list": [
  *     {
  *       "source": "http://www.example.com/download.txt",
  *       "target": "/home/user/Downloads/download.txt"
  *     },
  *     {
  *       "source": {
  *         "url": "http://www.example.com/download.txt",
  *         "referrer": "http://www.example.com/referrer.html"
  *       },
  *       "target": "/home/user/Downloads/download-2.txt"
  *     }
  *   ]
  * }
  */
 "use strict";
 this.EXPORTED_SYMBOLS = [
   "DownloadStore",
 ];
 ////////////////////////////////////////////////////////////////////////////////
 //// Globals
 const Cc = Components.classes;
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 const Cr = Components.results;
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "Downloads",
                                   "resource://gre/modules/Downloads.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "OS",
                                   "resource://gre/modules/osfile.jsm")
 XPCOMUtils.defineLazyModuleGetter(this, "Task",
                                   "resource://gre/modules/Task.jsm");
 XPCOMUtils.defineLazyGetter(this, "gTextDecoder", function () {
   return new TextDecoder();
 });
 XPCOMUtils.defineLazyGetter(this, "gTextEncoder", function () {
   return new TextEncoder();
 });
 ////////////////////////////////////////////////////////////////////////////////
 //// DownloadStore
 /**
  * Handles serialization of Download objects and persistence into a file, so
  * that the state of downloads can be restored across sessions.
  *
  * @param aList
  *        DownloadList object to be populated or serialized.
  * @param aPath
  *        String containing the file path where data should be saved.
  */
 this.DownloadStore = function (aList, aPath)
 {
   this.list = aList;
   this.path = aPath;
 }
 this.DownloadStore.prototype = {
   /**
    * DownloadList object to be populated or serialized.
    */
   list: null,
   /**
    * String containing the file path where data should be saved.
    */
   path: "",
   /**
    * This function is called with a Download object as its first argument, and
    * should return true if the item should be saved.
    */
   onsaveitem: () => true,
   /**
    * Loads persistent downloads from the file to the list.
    *
    * @return {Promise}
    * @resolves When the operation finished successfully.
    * @rejects JavaScript exception.
    */
   load: function DS_load()
   {
     return Task.spawn(function task_DS_load() {
       let bytes;
       try {
         bytes = yield OS.File.read(this.path);
       } catch (ex if ex instanceof OS.File.Error && ex.becauseNoSuchFile) {
         // If the file does not exist, there are no downloads to load.
         return;
       }
       let storeData = JSON.parse(gTextDecoder.decode(bytes));
       // Create live downloads based on the static snapshot.
       for (let downloadData of storeData.list) {
         try {
           let download = yield Downloads.createDownload(downloadData);
           try {
             if (!download.succeeded && !download.canceled && !download.error) {
               // Try to restart the download if it was in progress during the
               // previous session.
               download.start();
             } else {
               // If the download was not in progress, try to update the current
               // progress from disk.  This is relevant in case we retained
               // partially downloaded data.
               yield download.refresh();
             }
           } finally {
             // Add the download to the list if we succeeded in creating it,
             // after we have updated its initial state.
             yield this.list.add(download);
           }
         } catch (ex) {
           // If an item is unrecognized, don't prevent others from being loaded.
           Cu.reportError(ex);
         }
       }
     }.bind(this));
   },
   /**
    * Saves persistent downloads from the list to the file.
    *
    * If an error occurs, the previous file is not deleted.
    *
    * @return {Promise}
    * @resolves When the operation finished successfully.
    * @rejects JavaScript exception.
    */
   save: function DS_save()
   {
     return Task.spawn(function task_DS_save() {
       let downloads = yield this.list.getAll();
       // Take a static snapshot of the current state of all the downloads.
       let storeData = { list: [] };
       let atLeastOneDownload = false;
       for (let download of downloads) {
         try {
           if (!this.onsaveitem(download)) {
             continue;
           }
           storeData.list.push(download.toSerializable());
           atLeastOneDownload = true;
         } catch (ex) {
           // If an item cannot be converted to a serializable form, don't
           // prevent others from being saved.
           Cu.reportError(ex);
         }
       }
       if (atLeastOneDownload) {
         // Create or overwrite the file if there are downloads to save.
         let bytes = gTextEncoder.encode(JSON.stringify(storeData));
         yield OS.File.writeAtomic(this.path, bytes,
                                   { tmpPath: this.path + ".tmp" });
       } else {
         // Remove the file if there are no downloads to save at all.
         try {
           yield OS.File.remove(this.path);
         } catch (ex if ex instanceof OS.File.Error &&
                  (ex.becauseNoSuchFile || ex.becauseAccessDenied)) {
           // On Windows, we may get an access denied error instead of a no such
           // file error if the file existed before, and was recently deleted.
         }
       }
     }.bind(this));
   },
 };

The Tor Browser / annotate

toolkit/components/jsdownloads/src/DownloadStore.jsm@6474c204b198 (annotated)

toolkit/components/jsdownloads/src/DownloadStore.jsm