sbFileDownloader.js

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/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 :miv */
/*
 *=BEGIN SONGBIRD GPL
 *
 * This file is part of the Songbird web player.
 *
 * Copyright(c) 2005-2010 POTI, Inc.
 * http://www.songbirdnest.com
 *
 * This file may be licensed under the terms of of the
 * GNU General Public License Version 2 (the ``GPL'').
 *
 * Software distributed under the License is distributed
 * on an ``AS IS'' basis, WITHOUT WARRANTY OF ANY KIND, either
 * express or implied. See the GPL for the specific language
 * governing rights and limitations.
 *
 * You should have received a copy of the GPL along with this
 * program. If not, go to http://www.gnu.org/licenses/gpl.html
 * or write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 *=END SONGBIRD GPL
 */

//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
//
// File downloader component.
//
//   This component provides support for downloading files.
//
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------

//------------------------------------------------------------------------------
//
// File downloader imported services.
//
//------------------------------------------------------------------------------

// Component manager defs.
if (typeof(Cc) == "undefined")
  var Cc = Components.classes;
if (typeof(Ci) == "undefined")
  var Ci = Components.interfaces;
if (typeof(Cr) == "undefined")
  var Cr = Components.results;
if (typeof(Cu) == "undefined")
  var Cu = Components.utils;

// Songbird imports.
Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");


//------------------------------------------------------------------------------
//
// File downloader configuration.
//
//------------------------------------------------------------------------------

//
// classDescription             Description of component class.
// classID                      Component class ID.
// contractID                   Component contract ID.
// ifList                       List of external component interfaces.
// _xpcom_categories            List of component categories.
//

var sbFileDownloaderCfg= {
  classDescription: "File Downloader",
  classID: Components.ID("{f93a67e4-d97d-4607-971e-00ae2bf8ef8f}"),
  contractID: "@songbirdnest.com/Songbird/FileDownloader;1",
  ifList: [ Ci.sbIFileDownloader, Ci.nsIWebProgressListener ],
  _xpcom_categories: []
};


//------------------------------------------------------------------------------
//
// File downloader object.
//
//------------------------------------------------------------------------------

function sbFileDownloader() {
}

// Define the object.
sbFileDownloader.prototype = {
  // Set the constructor.
  constructor: sbFileDownloader,

  //
  // File downloader component configuration fields.
  //
  //   classDescription         Description of component class.
  //   classID                  Component class ID.
  //   contractID               Component contract ID.
  //   _xpcom_categories        List of component categories.
  //

  classDescription: sbFileDownloaderCfg.classDescription,
  classID: sbFileDownloaderCfg.classID,
  contractID: sbFileDownloaderCfg.contractID,
  _xpcom_categories: sbFileDownloaderCfg._xpcom_categories,


  //
  // File downloader fields.
  //
  //   _cfg                     Configuration settings.
  //   _webBrowserPersist       Web browser persist object.
  //

  _cfg: sbFileDownloaderCfg,
  _webBrowserPersist: null,


  //----------------------------------------------------------------------------
  //
  // File downloader sbIFileDownloader services.
  //
  //----------------------------------------------------------------------------

  bytesToDownload: 0,


  bytesDownloaded: 0,


  percentComplete: 0,


  complete: false,


  succeeded: false,


  listener: null,


  sourceURI: null,


  sourceURISpec: null,


  destinationFile: null,


  destinationFileExtension: null,


  temporaryFileFactory: null,


  start: function sbFileDownloader_start() {
    // Create a web browser persist object.
    this._webBrowserPersist =
           Cc["@mozilla.org/embedding/browser/nsWebBrowserPersist;1"]
             .createInstance(Ci.nsIWebBrowserPersist);
    this._webBrowserPersist.progressListener = this;
    this._webBrowserPersist.persistFlags =
           Ci.nsIWebBrowserPersist.PERSIST_FLAGS_REPLACE_EXISTING_FILES |
           Ci.nsIWebBrowserPersist.PERSIST_FLAGS_NO_CONVERSION |
           Ci.nsIWebBrowserPersist.PERSIST_FLAGS_BYPASS_CACHE;

    // If source URI is not provided, use source URI spec.
    if (!this.sourceURI && this.sourceURISpec) {
      var ioService = Cc["@mozilla.org/network/io-service;1"]
                        .getService(Ci.nsIIOService);
      this.sourceURI = ioService.newURI(this.sourceURISpec, null, null);
    }

    // Throw an exception if no source is specified.
    if (!this.sourceURI)
      throw Cr.NS_ERROR_INVALID_ARG;

    // If destination file is not provided, create a temporary one.
    //XXXeps if destination file is provided, should create a temporary one and
    //XXXeps move to destination when complete.
    if (!this.destinationFile) {
      if (this.temporaryFileFactory) {
        this.destinationFile =
          this.temporaryFileFactory.createFile(Ci.nsIFile.NORMAL_FILE_TYPE,
                                               null,
                                               this.destinationFileExtension);
      }
      else {
        var temporaryFileService =
              Cc["@songbirdnest.com/Songbird/TemporaryFileService;1"]
                .getService(Ci.sbITemporaryFileService);
        this.destinationFile =
               temporaryFileService.createFile(Ci.nsIFile.NORMAL_FILE_TYPE,
                                               null,
                                               this.destinationFileExtension);
      }
    }

    // Start the file download.
    this._webBrowserPersist.saveURI(this.sourceURI,
                                    null,
                                    null,
                                    null,
                                    null,
                                    this.destinationFile);
  },


  cancel: function sbFileDownloader_cancel() {
    // Cancel the file download.
    this._webBrowserPersist.cancelSave();
    this.request = null;
  },

  request: null,


  //----------------------------------------------------------------------------
  //
  // File downloader nsIWebProgressListener services.
  //
  //----------------------------------------------------------------------------

  onStateChange: function sbFileDownloader_onStateChange(aWebProgress,
                                                         aRequest,
                                                         aStateFlags,
                                                         aStatus) {
    if (!this.request) {
      this.request = aRequest;
    }

    // Check for completion.
    if (aStateFlags & Ci.nsIWebProgressListener.STATE_STOP) {
      // Mark completion.
      this.complete = true;

      // Check for HTTP channel failure.
      var httpChannelFailed = false;
      try {
        var httpChannel = aRequest.QueryInterface(Ci.nsIHttpChannel);
        httpChannelFailed = (httpChannel.requestSucceeded ? false : true);
      }
      catch (ex) {}

      // Mark success if aStatus is NS_OK and the HTTP channel did not fail.
      if ((aStatus == Cr.NS_OK) && !httpChannelFailed)
        this.succeeded = true;

      // The destination file may have been overwritten.  This can cause the
      // destination file object to be invalid.  Clone it to get a usable
      // object.
      if (this.destinationFile)
        this.destinationFile = this.destinationFile.clone();

      // Delete destination file on failure.
      if (!this.succeeded) {
        this.destinationFile.remove(false);
        this.destinationFile = null;
      }

      // Remove web browser persist listener reference to avoid a cycle.
      this._webBrowserPersist.progressListener = null;

      // Call file download listener.
      if (this.listener)
        this.listener.onComplete();
    }
  },


  onProgressChange:
    function sbFileDownloader_onProgressChange(aWebProgress,
                                               aRequest,
                                               aCurSelfProgress,
                                               aMaxSelfProgress,
                                               aCurTotalProgress,
                                               aMaxTotalProgress) {
    // Update the file download statistics.
    this.bytesToDownload = aMaxSelfProgress;
    this.bytesDownloaded = aCurSelfProgress;
    this.percentComplete =
           Math.floor((this.bytesDownloaded / this.bytesToDownload) * 100);

    // Call file download listener.
    if (this.listener)
      this.listener.onProgress();
  },


  onLocationChange: function sbFileDownloader_onLocationChange(aWebProgress,
                                                               aRequest,
                                                               aLocation) {
  },


  onStatusChange: function sbFileDownloader_onStatusChange(aWebProgress,
                                                           aRequest,
                                                           aStatus,
                                                           aMessage) {
  },


  onSecurityChange: function sbFileDownloader_onSecurityChange(aWebProgress,
                                                               aRequest,
                                                               aState) {
  },


  //----------------------------------------------------------------------------
  //
  // File downloader nsISupports services.
  //
  //----------------------------------------------------------------------------

  QueryInterface: XPCOMUtils.generateQI(sbFileDownloaderCfg.ifList)
};


//------------------------------------------------------------------------------
//
// File downloader component services.
//
//------------------------------------------------------------------------------

function NSGetModule(compMgr, fileSpec) {
  return XPCOMUtils.generateModule([sbFileDownloader]);
}