The Tor Browser: toolkit/components/jsdownloads/src/DownloadLegacy.js@b8a032363ba2 (annotated)

toolkit/components/jsdownloads/src/DownloadLegacy.js@b8a032363ba2 (annotated)

toolkit/components/jsdownloads/src/DownloadLegacy.js

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* 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/. */
 /**
  * This component implements the XPCOM interfaces required for integration with
  * the legacy download components.
  *
  * New code is expected to use the "Downloads.jsm" module directly, without
  * going through the interfaces implemented in this XPCOM component.  These
  * interfaces are only maintained for backwards compatibility with components
  * that still work synchronously on the main thread.
  */
 "use strict";
 ////////////////////////////////////////////////////////////////////////////////
 //// 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, "Promise",
                                   "resource://gre/modules/Promise.jsm");
 ////////////////////////////////////////////////////////////////////////////////
 //// DownloadLegacyTransfer
 /**
  * nsITransfer implementation that provides a bridge to a Download object.
  *
  * Legacy downloads work differently than the JavaScript implementation.  In the
  * latter, the caller only provides the properties for the Download object and
  * the entire process is handled by the "start" method.  In the legacy
  * implementation, the caller must create a separate object to execute the
  * download, and then make the download visible to the user by hooking it up to
  * an nsITransfer instance.
  *
  * Since nsITransfer instances may be created before the download system is
  * initialized, and initialization as well as other operations are asynchronous,
  * this implementation is able to delay all progress and status notifications it
  * receives until the associated Download object is finally created.
  *
  * Conversely, the DownloadLegacySaver object can also receive execution and
  * cancellation requests asynchronously, before or after it is connected to
  * this nsITransfer instance.  For that reason, those requests are communicated
  * in a potentially deferred way, using promise objects.
  *
  * The component that executes the download implements nsICancelable to receive
  * cancellation requests, but after cancellation it cannot be reused again.
  *
  * Since the components that execute the download may be different and they
  * don't always give consistent results, this bridge takes care of enforcing the
  * expectations, for example by ensuring the target file exists when the
  * download is successful, even if the source has a size of zero bytes.
  */
 function DownloadLegacyTransfer()
 {
   this._deferDownload = Promise.defer();
 }
 DownloadLegacyTransfer.prototype = {
   classID: Components.ID("{1b4c85df-cbdd-4bb6-b04e-613caece083c}"),
   //////////////////////////////////////////////////////////////////////////////
   //// nsISupports
   QueryInterface: XPCOMUtils.generateQI([Ci.nsIWebProgressListener,
                                          Ci.nsIWebProgressListener2,
                                          Ci.nsITransfer]),
   //////////////////////////////////////////////////////////////////////////////
   //// nsIWebProgressListener
   onStateChange: function DLT_onStateChange(aWebProgress, aRequest, aStateFlags,
                                             aStatus)
   {
     if (!Components.isSuccessCode(aStatus)) {
       this._componentFailed = true;
     }
     if ((aStateFlags & Ci.nsIWebProgressListener.STATE_START) &&
         (aStateFlags & Ci.nsIWebProgressListener.STATE_IS_NETWORK)) {
       // If the request's response has been blocked by Windows Parental Controls
       // with an HTTP 450 error code, we must cancel the request synchronously.
       let blockedByParentalControls = aRequest instanceof Ci.nsIHttpChannel &&
                                       aRequest.responseStatus == 450;
       if (blockedByParentalControls) {
         aRequest.cancel(Cr.NS_BINDING_ABORTED);
       }
       // The main request has just started.  Wait for the associated Download
       // object to be available before notifying.
       this._deferDownload.promise.then(download => {
         // If the request was blocked, now that we have the download object we
         // should set a flag that can be retrieved later when handling the
         // cancellation so that the proper error can be thrown.
         if (blockedByParentalControls) {
           download._blockedByParentalControls = true;
         }
         download.saver.onTransferStarted(
                          aRequest,
                          this._cancelable instanceof Ci.nsIHelperAppLauncher);
         // To handle asynchronous cancellation properly, we should hook up the
         // handler only after we have been notified that the main request
         // started.  We will wait until the main request stopped before
         // notifying that the download has been canceled.  Since the request has
         // not completed yet, deferCanceled is guaranteed to be set.
         return download.saver.deferCanceled.promise.then(() => {
           // Only cancel if the object executing the download is still running.
           if (this._cancelable && !this._componentFailed) {
             this._cancelable.cancel(Cr.NS_ERROR_ABORT);
             if (this._cancelable instanceof Ci.nsIWebBrowserPersist) {
               // This component will not send the STATE_STOP notification.
               download.saver.onTransferFinished(aRequest, Cr.NS_ERROR_ABORT);
               this._cancelable = null;
             }
           }
         });
       }).then(null, Cu.reportError);
     } else if ((aStateFlags & Ci.nsIWebProgressListener.STATE_STOP) &&
         (aStateFlags & Ci.nsIWebProgressListener.STATE_IS_NETWORK)) {
       // The last file has been received, or the download failed.  Wait for the
       // associated Download object to be available before notifying.
       this._deferDownload.promise.then(download => {
         // At this point, the hash has been set and we need to copy it to the
         // DownloadSaver.
         if (Components.isSuccessCode(aStatus)) {
           download.saver.setSha256Hash(this._sha256Hash);
           download.saver.setSignatureInfo(this._signatureInfo);
         }
         download.saver.onTransferFinished(aRequest, aStatus);
       }).then(null, Cu.reportError);
       // Release the reference to the component executing the download.
       this._cancelable = null;
     }
   },
   onProgressChange: function DLT_onProgressChange(aWebProgress, aRequest,
                                                   aCurSelfProgress,
                                                   aMaxSelfProgress,
                                                   aCurTotalProgress,
                                                   aMaxTotalProgress)
   {
     this.onProgressChange64(aWebProgress, aRequest, aCurSelfProgress,
                             aMaxSelfProgress, aCurTotalProgress,
                             aMaxTotalProgress);
   },
   onLocationChange: function () { },
   onStatusChange: function DLT_onStatusChange(aWebProgress, aRequest, aStatus,
                                               aMessage)
   {
     // The status change may optionally be received in addition to the state
     // change, but if no network request actually started, it is possible that
     // we only receive a status change with an error status code.
     if (!Components.isSuccessCode(aStatus)) {
       this._componentFailed = true;
       // Wait for the associated Download object to be available.
       this._deferDownload.promise.then(function DLT_OSC_onDownload(aDownload) {
         aDownload.saver.onTransferFinished(aRequest, aStatus);
       }).then(null, Cu.reportError);
     }
   },
   onSecurityChange: function () { },
   //////////////////////////////////////////////////////////////////////////////
   //// nsIWebProgressListener2
   onProgressChange64: function DLT_onProgressChange64(aWebProgress, aRequest,
                                                       aCurSelfProgress,
                                                       aMaxSelfProgress,
                                                       aCurTotalProgress,
                                                       aMaxTotalProgress)
   {
     // Wait for the associated Download object to be available.
     this._deferDownload.promise.then(function DLT_OPC64_onDownload(aDownload) {
       aDownload.saver.onProgressBytes(aCurTotalProgress, aMaxTotalProgress);
     }).then(null, Cu.reportError);
   },
   onRefreshAttempted: function DLT_onRefreshAttempted(aWebProgress, aRefreshURI,
                                                       aMillis, aSameURI)
   {
     // Indicate that refreshes and redirects are allowed by default.  However,
     // note that download components don't usually call this method at all.
     return true;
   },
   //////////////////////////////////////////////////////////////////////////////
   //// nsITransfer
   init: function DLT_init(aSource, aTarget, aDisplayName, aMIMEInfo, aStartTime,
                           aTempFile, aCancelable, aIsPrivate)
   {
     this._cancelable = aCancelable;
     let launchWhenSucceeded = false, contentType = null, launcherPath = null;
     if (aMIMEInfo instanceof Ci.nsIMIMEInfo) {
       launchWhenSucceeded =
                 aMIMEInfo.preferredAction != Ci.nsIMIMEInfo.saveToDisk;
       contentType = aMIMEInfo.type;
       let appHandler = aMIMEInfo.preferredApplicationHandler;
       if (aMIMEInfo.preferredAction == Ci.nsIMIMEInfo.useHelperApp &&
           appHandler instanceof Ci.nsILocalHandlerApp) {
         launcherPath = appHandler.executable.path;
       }
     }
     // Create a new Download object associated to a DownloadLegacySaver, and
     // wait for it to be available.  This operation may cause the entire
     // download system to initialize before the object is created.
     Downloads.createDownload({
       source: { url: aSource.spec, isPrivate: aIsPrivate },
       target: { path: aTarget.QueryInterface(Ci.nsIFileURL).file.path,
                 partFilePath: aTempFile && aTempFile.path },
       saver: "legacy",
       launchWhenSucceeded: launchWhenSucceeded,
       contentType: contentType,
       launcherPath: launcherPath
     }).then(function DLT_I_onDownload(aDownload) {
       // Legacy components keep partial data when they use a ".part" file.
       if (aTempFile) {
         aDownload.tryToKeepPartialData = true;
       }
       // Start the download before allowing it to be controlled.  Ignore errors.
       aDownload.start().then(null, () => {});
       // Start processing all the other events received through nsITransfer.
       this._deferDownload.resolve(aDownload);
       // Add the download to the list, allowing it to be seen and canceled.
       return Downloads.getList(Downloads.ALL).then(list => list.add(aDownload));
     }.bind(this)).then(null, Cu.reportError);
   },
   setSha256Hash: function (hash)
   {
     this._sha256Hash = hash;
   },
   setSignatureInfo: function (signatureInfo)
   {
     this._signatureInfo = signatureInfo;
   },
   //////////////////////////////////////////////////////////////////////////////
   //// Private methods and properties
   /**
    * This deferred object contains a promise that is resolved with the Download
    * object associated with this nsITransfer instance, when it is available.
    */
   _deferDownload: null,
   /**
    * Reference to the component that is executing the download.  This component
    * allows cancellation through its nsICancelable interface.
    */
   _cancelable: null,
   /**
    * Indicates that the component that executes the download has notified a
    * failure condition.  In this case, we should never use the component methods
    * that cancel the download.
    */
   _componentFailed: false,
   /**
    * Save the SHA-256 hash in raw bytes of the downloaded file.
    */
   _sha256Hash: null,
   /**
    * Save the signature info in a serialized protobuf of the downloaded file.
    */
   _signatureInfo: null,
 };
 ////////////////////////////////////////////////////////////////////////////////
 //// Module
 this.NSGetFactory = XPCOMUtils.generateNSGetFactory([DownloadLegacyTransfer]);