gecko/toolkit/mozapps/downloads/nsHelperAppDlg.js

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/*
# ***** BEGIN LICENSE BLOCK *****
# Version: MPL 1.1/GPL 2.0/LGPL 2.1
#
# The contents of this file are subject to the Mozilla Public License Version
# 1.1 (the "License"); you may not use this file except in compliance with
# the License. You may obtain a copy of the License at
# http://www.mozilla.org/MPL/
#
# Software distributed under the License is distributed on an "AS IS" basis,
# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
# for the specific language governing rights and limitations under the
# License.
#
# The Original Code is Mozilla.org Code.
#
# The Initial Developer of the Original Code is
# Doron Rosenberg.
# Portions created by the Initial Developer are Copyright (C) 2001
# the Initial Developer. All Rights Reserved.
#
# Contributor(s):
#   Bill Law <law@netscape.com>
#   Scott MacGregor <mscott@netscape.com>
#   Ben Goodger <ben@bengoodger.com> (2.0)
#   Fredrik Holmqvist <thesuckiestemail@yahoo.se>
#   Dan Mosedale <dmose@mozilla.org>
#   Jim Mathies <jmathies@mozilla.com>
#   Ehsan Akhgari <ehsan.akhgari@gmail.com>
#   Kailas Patil <patilkr24@gmail.com>
#
# Alternatively, the contents of this file may be used under the terms of
# either the GNU General Public License Version 2 or later (the "GPL"), or
# the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
# in which case the provisions of the GPL or the LGPL are applicable instead
# of those above. If you wish to allow use of your version of this file only
# under the terms of either the GPL or the LGPL, and not to allow others to
# use your version of this file under the terms of the MPL, indicate your
# decision by deleting the provisions above and replace them with the notice
# and other provisions required by the GPL or the LGPL. If you do not delete
# the provisions above, a recipient may use your version of this file under
# the terms of any one of the MPL, the GPL or the LGPL.
#
# ***** END LICENSE BLOCK *****
*/

///////////////////////////////////////////////////////////////////////////////
//// Helper Functions

/**
 * Determines if a given directory is able to be used to download to.
 *
 * @param aDirectory
 *        The directory to check.
 * @returns true if we can use the directory, false otherwise.
 */
function isUsableDirectory(aDirectory)
{
  return aDirectory.exists() && aDirectory.isDirectory() &&
         aDirectory.isWritable();
}

// Web progress listener so we can detect errors while mLauncher is
// streaming the data to a temporary file.
function nsUnkownContentTypeDialogProgressListener(aHelperAppDialog) {
  this.helperAppDlg = aHelperAppDialog;
}

nsUnkownContentTypeDialogProgressListener.prototype = {
  // nsIWebProgressListener methods.
  // Look for error notifications and display alert to user.
  onStatusChange: function( aWebProgress, aRequest, aStatus, aMessage ) {
    if ( aStatus != Components.results.NS_OK ) {
      // Get prompt service.
      var prompter = Components.classes[ "@mozilla.org/embedcomp/prompt-service;1" ]
                               .getService( Components.interfaces.nsIPromptService );
      // Display error alert (using text supplied by back-end).
      // FIXME this.dialog is undefined?
      prompter.alert( this.dialog, this.helperAppDlg.mTitle, aMessage );
      // Close the dialog.
      this.helperAppDlg.onCancel();
      if ( this.helperAppDlg.mDialog ) {
        this.helperAppDlg.mDialog.close();
      }
    }
  },

  // Ignore onProgressChange, onProgressChange64, onStateChange, onLocationChange, onSecurityChange, and onRefreshAttempted notifications.
  onProgressChange: function( aWebProgress,
                              aRequest,
                              aCurSelfProgress,
                              aMaxSelfProgress,
                              aCurTotalProgress,
                              aMaxTotalProgress ) {
  },

  onProgressChange64: function( aWebProgress,
                                aRequest,
                                aCurSelfProgress,
                                aMaxSelfProgress,
                                aCurTotalProgress,
                                aMaxTotalProgress ) {
  },



  onStateChange: function( aWebProgress, aRequest, aStateFlags, aStatus ) {
  },

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

  onSecurityChange: function( aWebProgress, aRequest, state ) {
  },

  onRefreshAttempted: function( aWebProgress, aURI, aDelay, aSameURI ) {
    return true;
  }
};

///////////////////////////////////////////////////////////////////////////////
//// nsUnkownContentTypeDialog

/* This file implements the nsIHelperAppLauncherDialog interface.
 *
 * The implementation consists of a JavaScript "class" named nsUnknownContentTypeDialog,
 * comprised of:
 *   - a JS constructor function
 *   - a prototype providing all the interface methods and implementation stuff
 *
 * In addition, this file implements an nsIModule object that registers the
 * nsUnknownContentTypeDialog component.
 */

const PREF_BD_USEDOWNLOADDIR = "browser.download.useDownloadDir";
const nsITimer = Components.interfaces.nsITimer;

Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
Components.utils.import("resource://gre/modules/DownloadLastDir.jsm");
Components.utils.import("resource://gre/modules/DownloadPaths.jsm");
Components.utils.import("resource://gre/modules/DownloadUtils.jsm");

/* ctor
 */
function nsUnknownContentTypeDialog() {
  // Initialize data properties.
  this.mLauncher = null;
  this.mContext  = null;
  this.mSourcePath = null;
  this.chosenApp = null;
  this.givenDefaultApp = false;
  this.updateSelf = true;
  this.mTitle    = "";
}

nsUnknownContentTypeDialog.prototype = {
  classID: Components.ID("{F68578EB-6EC2-4169-AE19-8C6243F0ABE1}"),

  nsIMIMEInfo  : Components.interfaces.nsIMIMEInfo,

  QueryInterface: function (iid) {
    if (!iid.equals(Components.interfaces.nsIHelperAppLauncherDialog) &&
        !iid.equals(Components.interfaces.nsITimerCallback) &&
        !iid.equals(Components.interfaces.nsISupports)) {
      throw Components.results.NS_ERROR_NO_INTERFACE;
    }
    return this;
  },

  // ---------- nsIHelperAppLauncherDialog methods ----------

  // show: Open XUL dialog using window watcher.  Since the dialog is not
  //       modal, it needs to be a top level window and the way to open
  //       one of those is via that route).
  show: function(aLauncher, aContext, aReason)  {
    this.mLauncher = aLauncher;
    this.mContext  = aContext;

    const nsITimer = Components.interfaces.nsITimer;
    this._showTimer = Components.classes["@mozilla.org/timer;1"]
                                .createInstance(nsITimer);
    this._showTimer.initWithCallback(this, 0, nsITimer.TYPE_ONE_SHOT);
  },

  // When opening from new tab, if tab closes while dialog is opening,
  // (which is a race condition on the XUL file being cached and the timer
  // in nsExternalHelperAppService), the dialog gets a blur and doesn't
  // activate the OK button.  So we wait a bit before doing opening it.
  reallyShow: function() {
    try {
      var ir = this.mContext.QueryInterface(Components.interfaces.nsIInterfaceRequestor);
      var dwi = ir.getInterface(Components.interfaces.nsIDOMWindow);
      var ww = Components.classes["@mozilla.org/embedcomp/window-watcher;1"]
                         .getService(Components.interfaces.nsIWindowWatcher);
      this.mDialog = ww.openWindow(dwi,
                                   "chrome://mozapps/content/downloads/unknownContentType.xul",
                                   null,
                                   "chrome,centerscreen,titlebar,dialog=yes,dependent",
                                   null);
    } catch (ex) {
      // The containing window may have gone away.  Break reference
      // cycles and stop doing the download.
      const NS_BINDING_ABORTED = 0x804b0002;
      this.mLauncher.cancel(NS_BINDING_ABORTED);
      return;
    }

    // Hook this object to the dialog.
    this.mDialog.dialog = this;

    // Hook up utility functions.
    this.getSpecialFolderKey = this.mDialog.getSpecialFolderKey;

    // Watch for error notifications.
    var progressListener = new nsUnkownContentTypeDialogProgressListener(this);
    this.mLauncher.setWebProgressListener(progressListener);
  },

  // promptForSaveToFile:  Display file picker dialog and return selected file.
  //                       This is called by the External Helper App Service
  //                       after the ucth dialog calls |saveToDisk| with a null
  //                       target filename (no target, therefore user must pick).
  //
  //                       Alternatively, if the user has selected to have all
  //                       files download to a specific location, return that
  //                       location and don't ask via the dialog.
  //
  // Note - this function is called without a dialog, so it cannot access any part
  // of the dialog XUL as other functions on this object do.
  promptForSaveToFile: function(aLauncher, aContext, aDefaultFile, aSuggestedFileExtension, aForcePrompt) {
    var result = null;

    this.mLauncher = aLauncher;

    let prefs = Components.classes["@mozilla.org/preferences-service;1"]
                          .getService(Components.interfaces.nsIPrefBranch);
    let bundle = Components.classes["@mozilla.org/intl/stringbundle;1"].
                            getService(Components.interfaces.nsIStringBundleService).
                            createBundle("chrome://mozapps/locale/downloads/unknownContentType.properties");

    if (!aForcePrompt) {
      // Check to see if the user wishes to auto save to the default download
      // folder without prompting. Note that preference might not be set.
      let autodownload = false;
      try {
        autodownload = prefs.getBoolPref(PREF_BD_USEDOWNLOADDIR);
      } catch (e) { }

      if (autodownload) {
        // Retrieve the user's default download directory
        let dnldMgr = Components.classes["@mozilla.org/download-manager;1"]
                                .getService(Components.interfaces.nsIDownloadManager);
        let defaultFolder = dnldMgr.userDownloadsDirectory;

        try {
          result = this.validateLeafName(defaultFolder, aDefaultFile, aSuggestedFileExtension);
        }
        catch (ex) {
          if (ex.result == Components.results.NS_ERROR_FILE_ACCESS_DENIED) {
            let prompter = Components.classes["@mozilla.org/embedcomp/prompt-service;1"].
                                      getService(Components.interfaces.nsIPromptService);

            // Display error alert (using text supplied by back-end)
            prompter.alert(this.dialog,
                           bundle.GetStringFromName("badPermissions.title"),
                           bundle.GetStringFromName("badPermissions"));

            return;
          }
        }

        // Check to make sure we have a valid directory, otherwise, prompt
        if (result)
          return result;
      }
    }

    // Use file picker to show dialog.
    var nsIFilePicker = Components.interfaces.nsIFilePicker;
    var picker = Components.classes["@mozilla.org/filepicker;1"].createInstance(nsIFilePicker);
    var windowTitle = bundle.GetStringFromName("saveDialogTitle");
    var parent = aContext.QueryInterface(Components.interfaces.nsIInterfaceRequestor).getInterface(Components.interfaces.nsIDOMWindow);
    picker.init(parent, windowTitle, nsIFilePicker.modeSave);
    picker.defaultString = aDefaultFile;

    if (aSuggestedFileExtension) {
      // aSuggestedFileExtension includes the period, so strip it
      picker.defaultExtension = aSuggestedFileExtension.substring(1);
    }
    else {
      try {
        picker.defaultExtension = this.mLauncher.MIMEInfo.primaryExtension;
      }
      catch (ex) { }
    }

    var wildCardExtension = "*";
    if (aSuggestedFileExtension) {
      wildCardExtension += aSuggestedFileExtension;
      picker.appendFilter(this.mLauncher.MIMEInfo.description, wildCardExtension);
    }

    picker.appendFilters( nsIFilePicker.filterAll );

    // Default to lastDir if it is valid, otherwise use the user's default
    // downloads directory.  userDownloadsDirectory should always return a
    // valid directory, so we can safely default to it.
    var dnldMgr = Components.classes["@mozilla.org/download-manager;1"]
                            .getService(Components.interfaces.nsIDownloadManager);
    picker.displayDirectory = dnldMgr.userDownloadsDirectory;

    var relatedURI = null;
    if (aContext.document)
      relatedURI = aContext.document.documentURIObject;

    // The last directory preference may not exist, which will throw.
    try {
      var lastDir = gDownloadLastDir.getFile(relatedURI);
      if (isUsableDirectory(lastDir))
        picker.displayDirectory = lastDir;
    }
    catch (ex) {
    }

    if (picker.show() == nsIFilePicker.returnCancel) {
      // null result means user cancelled.
      return null;
    }

    // Be sure to save the directory the user chose through the Save As...
    // dialog  as the new browser.download.dir since the old one
    // didn't exist.
    result = picker.file;

    if (result) {
      try {
        // Remove the file so that it's not there when we ensure non-existence later;
        // this is safe because for the file to exist, the user would have had to
        // confirm that he wanted the file overwritten.
        if (result.exists())
          result.remove(false);
      }
      catch (e) { }
      var newDir = result.parent.QueryInterface(Components.interfaces.nsILocalFile);

      // Do not store the last save directory as a pref inside the private browsing mode
      gDownloadLastDir.setFile(relatedURI, newDir);

      result = this.validateLeafName(newDir, result.leafName, null);
    }
    return result;
  },

  /**
   * Ensures that a local folder/file combination does not already exist in
   * the file system (or finds such a combination with a reasonably similar
   * leaf name), creates the corresponding file, and returns it.
   *
   * @param   aLocalFile
   *          the folder where the file resides
   * @param   aLeafName
   *          the string name of the file (may be empty if no name is known,
   *          in which case a name will be chosen)
   * @param   aFileExt
   *          the extension of the file, if one is known; this will be ignored
   *          if aLeafName is non-empty
   * @returns nsILocalFile
   *          the created file
   */
  validateLeafName: function (aLocalFile, aLeafName, aFileExt)
  {
    if (!(aLocalFile && isUsableDirectory(aLocalFile)))
      return null;

    // Remove any leading periods, since we don't want to save hidden files
    // automatically.
    aLeafName = aLeafName.replace(/^\.+/, "");

    if (aLeafName == "")
      aLeafName = "unnamed" + (aFileExt ? "." + aFileExt : "");
    aLocalFile.append(aLeafName);

    var createdFile = DownloadPaths.createNiceUniqueFile(aLocalFile);

#ifdef XP_WIN
    let ext;
    try {
      // We can fail here if there's no primary extension set
      ext = "." + this.mLauncher.MIMEInfo.primaryExtension;
    } catch (e) { }

    // Append a file extension if it's an executable that doesn't have one
    // but make sure we actually have an extension to add
    let leaf = createdFile.leafName;
    if (ext && leaf.slice(-ext.length) != ext && createdFile.isExecutable()) {
      createdFile.remove(false);
      aLocalFile.leafName = leaf + ext;
      createdFile = DownloadPaths.createNiceUniqueFile(aLocalFile);
    }
#endif

    return createdFile;
  },

  // ---------- implementation methods ----------

  // initDialog:  Fill various dialog fields with initial content.
  initDialog : function() {
    // Put file name in window title.
    var suggestedFileName = this.mLauncher.suggestedFileName;

    // Some URIs do not implement nsIURL, so we can't just QI.
    var url   = this.mLauncher.source;
    var fname = "";
    var iconPath = "goat";
    this.mSourcePath = url.prePath;
    if (url instanceof Components.interfaces.nsIURL) {
      // A url, use file name from it.
      fname = iconPath = url.fileName;
      this.mSourcePath += url.directory;
    } else {
      // A generic uri, use path.
      fname = url.path;
      this.mSourcePath += url.path;
    }

    if (suggestedFileName)
      fname = iconPath = suggestedFileName;

    var displayName = fname.replace(/ +/g, " ");

    this.mTitle = this.dialogElement("strings").getFormattedString("title", [displayName]);
    this.mDialog.document.title = this.mTitle;

    // Put content type, filename and location into intro.
    this.initIntro(url, fname, displayName);

    var iconString = "moz-icon://" + iconPath + "?size=16&contentType=" + this.mLauncher.MIMEInfo.MIMEType;
    this.dialogElement("contentTypeImage").setAttribute("src", iconString);

    // if always-save and is-executable and no-handler
    // then set up simple ui
    var mimeType = this.mLauncher.MIMEInfo.MIMEType;
    var shouldntRememberChoice = (mimeType == "application/octet-stream" ||
                                  mimeType == "application/x-msdownload" ||
                                  this.mLauncher.targetFileIsExecutable);
    if (shouldntRememberChoice && !this.openWithDefaultOK()) {
      // hide featured choice
      this.dialogElement("normalBox").collapsed = true;
      // show basic choice
      this.dialogElement("basicBox").collapsed = false;
      // change button labels and icons; use "save" icon for the accept
      // button since it's the only action possible
      let acceptButton = this.mDialog.document.documentElement
                                              .getButton("accept");
      acceptButton.label = this.dialogElement("strings")
                               .getString("unknownAccept.label");
      acceptButton.setAttribute("icon", "save");
      this.mDialog.document.documentElement.getButton("cancel").label = this.dialogElement("strings").getString("unknownCancel.label");
      // hide other handler
      this.dialogElement("openHandler").collapsed = true;
      // set save as the selected option
      this.dialogElement("mode").selectedItem = this.dialogElement("save");
    }
    else {
      this.initAppAndSaveToDiskValues();

      // Initialize "always ask me" box. This should always be disabled
      // and set to true for the ambiguous type application/octet-stream.
      // We don't also check for application/x-msdownload here since we
      // want users to be able to autodownload .exe files.
      var rememberChoice = this.dialogElement("rememberChoice");

#if 0
      // Just because we have a content-type of application/octet-stream
      // here doesn't actually mean that the content is of that type. Many
      // servers default to sending text/plain for file types they don't know
      // about. To account for this, the uriloader does some checking to see
      // if a file sent as text/plain contains binary characters, and if so (*)
      // it morphs the content-type into application/octet-stream so that
      // the file can be properly handled. Since this is not generic binary
      // data, rather, a data format that the system probably knows about,
      // we don't want to use the content-type provided by this dialog's
      // opener, as that's the generic application/octet-stream that the
      // uriloader has passed, rather we want to ask the MIME Service.
      // This is so we don't needlessly disable the "autohandle" checkbox.

      // commented out to close the opening brace in the if statement.
      // var mimeService = Components.classes["@mozilla.org/mime;1"].getService(Components.interfaces.nsIMIMEService);
      // var type = mimeService.getTypeFromURI(this.mLauncher.source);
      // this.realMIMEInfo = mimeService.getFromTypeAndExtension(type, "");

      // if (type == "application/octet-stream") {
#endif
      if (shouldntRememberChoice) {
        rememberChoice.checked = false;
        rememberChoice.disabled = true;
      }
      else {
        rememberChoice.checked = !this.mLauncher.MIMEInfo.alwaysAskBeforeHandling;
      }
      this.toggleRememberChoice(rememberChoice);

      // XXXben - menulist won't init properly, hack.
      var openHandler = this.dialogElement("openHandler");
      openHandler.parentNode.removeChild(openHandler);
      var openHandlerBox = this.dialogElement("openHandlerBox");
      openHandlerBox.appendChild(openHandler);
    }

    this.mDialog.setTimeout("dialog.postShowCallback()", 0);

    this.mDialog.document.documentElement.getButton("accept").disabled = true;
    this._showTimer = Components.classes["@mozilla.org/timer;1"]
                                .createInstance(nsITimer);
    this._showTimer.initWithCallback(this, 250, nsITimer.TYPE_ONE_SHOT);
  },

  notify: function (aTimer) {
    if (aTimer == this._showTimer) {
      if (!this.mDialog) {
        this.reallyShow();
      } else {
        // The user may have already canceled the dialog.
        try {
          if (!this._blurred) {
            this.mDialog.document.documentElement.getButton("accept").disabled = false;
          }
        } catch (ex) {}
        this._delayExpired = true;
      }
      // The timer won't release us, so we have to release it.
      this._showTimer = null;
    }
    else if (aTimer == this._saveToDiskTimer) {
      // Since saveToDisk may open a file picker and therefore block this routine,
      // we should only call it once the dialog is closed.
      this.mLauncher.saveToDisk(null, false);
      this._saveToDiskTimer = null;
    }
  },

  postShowCallback: function () {
    this.mDialog.sizeToContent();

    // Set initial focus
    this.dialogElement("mode").focus();
  },

  // initIntro:
  initIntro: function(url, filename, displayname) {
    this.dialogElement( "location" ).value = displayname;
    this.dialogElement( "location" ).setAttribute("realname", filename);
    this.dialogElement( "location" ).setAttribute("tooltiptext", displayname);

    // if mSourcePath is a local file, then let's use the pretty path name instead of an ugly
    // url...
    var pathString = this.mSourcePath;
    try
    {
      var fileURL = url.QueryInterface(Components.interfaces.nsIFileURL);
      if (fileURL)
      {
        var fileObject = fileURL.file;
        if (fileObject)
        {
          var parentObject = fileObject.parent;
          if (parentObject)
          {
            pathString = parentObject.path;
          }
        }
      }
    } catch(ex) {}

    if (pathString == this.mSourcePath)
    {
      // wasn't a fileURL
      var tmpurl = url.clone(); // don't want to change the real url
      try {
        tmpurl.userPass = "";
      } catch (ex) {}
      pathString = tmpurl.prePath;
    }

    // Set the location text, which is separate from the intro text so it can be cropped
    var location = this.dialogElement( "source" );
    location.value = pathString;
    location.setAttribute("tooltiptext", this.mSourcePath);

    // Show the type of file.
    var type = this.dialogElement("type");
    var mimeInfo = this.mLauncher.MIMEInfo;

    // 1. Try to use the pretty description of the type, if one is available.
    var typeString = mimeInfo.description;

    if (typeString == "") {
      // 2. If there is none, use the extension to identify the file, e.g. "ZIP file"
      var primaryExtension = "";
      try {
        primaryExtension = mimeInfo.primaryExtension;
      }
      catch (ex) {
      }
      if (primaryExtension != "")
        typeString = this.dialogElement("strings").getFormattedString("fileType", [primaryExtension.toUpperCase()]);
      // 3. If we can't even do that, just give up and show the MIME type.
      else
        typeString = mimeInfo.MIMEType;
    }
    if (this.mLauncher.contentLength) {
      let [size, unit] = DownloadUtils.
                         convertByteUnits(this.mLauncher.contentLength);
      type.value = this.dialogElement("strings")
                       .getFormattedString("fileSizeWithType", 
                                           [typeString, size, unit]);
    }
    else {
      type.value = typeString;
    }
  },

  _blurred: false,
  _delayExpired: false,
  onBlur: function(aEvent) {
    this._blurred = true;
    this.mDialog.document.documentElement.getButton("accept").disabled = true;
  },

  onFocus: function(aEvent) {
    this._blurred = false;
    if (this._delayExpired) {
      var script = "document.documentElement.getButton('accept').disabled = false";
      this.mDialog.setTimeout(script, 250);
    }
  },

  // Returns true if opening the default application makes sense.
  openWithDefaultOK: function() {
    // The checking is different on Windows...
#ifdef XP_WIN
    // Windows presents some special cases.
    // We need to prevent use of "system default" when the file is
    // executable (so the user doesn't launch nasty programs downloaded
    // from the web), and, enable use of "system default" if it isn't
    // executable (because we will prompt the user for the default app
    // in that case).

    //  Default is Ok if the file isn't executable (and vice-versa).
    return !this.mLauncher.targetFileIsExecutable;
#else
    // On other platforms, default is Ok if there is a default app.
    // Note that nsIMIMEInfo providers need to ensure that this holds true
    // on each platform.
    return this.mLauncher.MIMEInfo.hasDefaultHandler;
#endif
  },

  // Set "default" application description field.
  initDefaultApp: function() {
    // Use description, if we can get one.
    var desc = this.mLauncher.MIMEInfo.defaultDescription;
    if (desc) {
      var defaultApp = this.dialogElement("strings").getFormattedString("defaultApp", [desc]);
      this.dialogElement("defaultHandler").label = defaultApp;
    }
    else {
      this.dialogElement("modeDeck").setAttribute("selectedIndex", "1");
      // Hide the default handler item too, in case the user picks a
      // custom handler at a later date which triggers the menulist to show.
      this.dialogElement("defaultHandler").hidden = true;
    }
  },

  // getPath:
  getPath: function (aFile) {
#ifdef XP_MACOSX
    return aFile.leafName || aFile.path;
#else
    return aFile.path;
#endif
  },

  // initAppAndSaveToDiskValues:
  initAppAndSaveToDiskValues: function() {
    var modeGroup = this.dialogElement("mode");

    // We don't let users open .exe files or random binary data directly
    // from the browser at the moment because of security concerns.
    var openWithDefaultOK = this.openWithDefaultOK();
    var mimeType = this.mLauncher.MIMEInfo.MIMEType;
    if (this.mLauncher.targetFileIsExecutable || (
      (mimeType == "application/octet-stream" ||
       mimeType == "application/x-msdownload") &&
        !openWithDefaultOK)) {
      this.dialogElement("open").disabled = true;
      var openHandler = this.dialogElement("openHandler");
      openHandler.disabled = true;
      openHandler.selectedItem = null;
      modeGroup.selectedItem = this.dialogElement("save");
      return;
    }

    // Fill in helper app info, if there is any.
    try {
      this.chosenApp =
        this.mLauncher.MIMEInfo.preferredApplicationHandler
                               .QueryInterface(Components.interfaces.nsILocalHandlerApp);
    } catch (e) {
      this.chosenApp = null;
    }
    // Initialize "default application" field.
    this.initDefaultApp();

    var otherHandler = this.dialogElement("otherHandler");

    // Fill application name textbox.
    if (this.chosenApp && this.chosenApp.executable &&
        this.chosenApp.executable.path) {
      otherHandler.setAttribute("path",
                                this.getPath(this.chosenApp.executable));

      otherHandler.label = this.getFileDisplayName(this.chosenApp.executable);
      otherHandler.hidden = false;
    }

    var useDefault = this.dialogElement("useSystemDefault");
    var openHandler = this.dialogElement("openHandler");
    openHandler.selectedIndex = 0;

    if (this.mLauncher.MIMEInfo.preferredAction == this.nsIMIMEInfo.useSystemDefault) {
      // Open (using system default).
      modeGroup.selectedItem = this.dialogElement("open");
    } else if (this.mLauncher.MIMEInfo.preferredAction == this.nsIMIMEInfo.useHelperApp) {
      // Open with given helper app.
      modeGroup.selectedItem = this.dialogElement("open");
      openHandler.selectedIndex = 1;
    } else {
      // Save to disk.
      modeGroup.selectedItem = this.dialogElement("save");
    }

    // If we don't have a "default app" then disable that choice.
    if (!openWithDefaultOK) {
      var useDefault = this.dialogElement("defaultHandler");
      var isSelected = useDefault.selected;

      // Disable that choice.
      useDefault.hidden = true;
      // If that's the default, then switch to "save to disk."
      if (isSelected) {
        openHandler.selectedIndex = 1;
        modeGroup.selectedItem = this.dialogElement("save");
      }
    }

    otherHandler.nextSibling.hidden = otherHandler.nextSibling.nextSibling.hidden = false;
    this.updateOKButton();
  },

  // Returns the user-selected application
  helperAppChoice: function() {
    return this.chosenApp;
  },

  get saveToDisk() {
    return this.dialogElement("save").selected;
  },

  get useOtherHandler() {
    return this.dialogElement("open").selected && this.dialogElement("openHandler").selectedIndex == 1;
  },

  get useSystemDefault() {
    return this.dialogElement("open").selected && this.dialogElement("openHandler").selectedIndex == 0;
  },

  toggleRememberChoice: function (aCheckbox) {
    this.dialogElement("settingsChange").hidden = !aCheckbox.checked;
    this.mDialog.sizeToContent();
  },

  openHandlerCommand: function () {
    var openHandler = this.dialogElement("openHandler");
    if (openHandler.selectedItem.id == "choose")
      this.chooseApp();
    else
      openHandler.setAttribute("lastSelectedItemID", openHandler.selectedItem.id);
  },

  updateOKButton: function() {
    var ok = false;
    if (this.dialogElement("save").selected) {
      // This is always OK.
      ok = true;
    }
    else if (this.dialogElement("open").selected) {
      switch (this.dialogElement("openHandler").selectedIndex) {
      case 0:
        // No app need be specified in this case.
        ok = true;
        break;
      case 1:
        // only enable the OK button if we have a default app to use or if
        // the user chose an app....
        ok = this.chosenApp || /\S/.test(this.dialogElement("otherHandler").getAttribute("path")); 
        break;
      }
    }

    // Enable Ok button if ok to press.
    this.mDialog.document.documentElement.getButton("accept").disabled = !ok;
  },

  // Returns true iff the user-specified helper app has been modified.
  appChanged: function() {
    return this.helperAppChoice() != this.mLauncher.MIMEInfo.preferredApplicationHandler;
  },

  updateMIMEInfo: function() {
    var needUpdate = false;
    // If current selection differs from what's in the mime info object,
    // then we need to update.
    if (this.saveToDisk) {
      needUpdate = this.mLauncher.MIMEInfo.preferredAction != this.nsIMIMEInfo.saveToDisk;
      if (needUpdate)
        this.mLauncher.MIMEInfo.preferredAction = this.nsIMIMEInfo.saveToDisk;
    }
    else if (this.useSystemDefault) {
      needUpdate = this.mLauncher.MIMEInfo.preferredAction != this.nsIMIMEInfo.useSystemDefault;
      if (needUpdate)
        this.mLauncher.MIMEInfo.preferredAction = this.nsIMIMEInfo.useSystemDefault;
    }
    else {
      // For "open with", we need to check both preferred action and whether the user chose
      // a new app.
      needUpdate = this.mLauncher.MIMEInfo.preferredAction != this.nsIMIMEInfo.useHelperApp || this.appChanged();
      if (needUpdate) {
        this.mLauncher.MIMEInfo.preferredAction = this.nsIMIMEInfo.useHelperApp;
        // App may have changed - Update application
        var app = this.helperAppChoice();
        this.mLauncher.MIMEInfo.preferredApplicationHandler = app;
      }
    }
    // We will also need to update if the "always ask" flag has changed.
    needUpdate = needUpdate || this.mLauncher.MIMEInfo.alwaysAskBeforeHandling != (!this.dialogElement("rememberChoice").checked);

    // One last special case: If the input "always ask" flag was false, then we always
    // update.  In that case we are displaying the helper app dialog for the first
    // time for this mime type and we need to store the user's action in the mimeTypes.rdf
    // data source (whether that action has changed or not; if it didn't change, then we need
    // to store the "always ask" flag so the helper app dialog will or won't display
    // next time, per the user's selection).
    needUpdate = needUpdate || !this.mLauncher.MIMEInfo.alwaysAskBeforeHandling;

    // Make sure mime info has updated setting for the "always ask" flag.
    this.mLauncher.MIMEInfo.alwaysAskBeforeHandling = !this.dialogElement("rememberChoice").checked;

    return needUpdate;
  },

  // See if the user changed things, and if so, update the
  // mimeTypes.rdf entry for this mime type.
  updateHelperAppPref: function() {
    var ha = new this.mDialog.HelperApps();
    ha.updateTypeInfo(this.mLauncher.MIMEInfo);
    ha.destroy();
  },

  // onOK:
  onOK: function() {
    // Verify typed app path, if necessary.
    if (this.useOtherHandler) {
      var helperApp = this.helperAppChoice();
      if (!helperApp || !helperApp.executable ||
          !helperApp.executable.exists()) {
        // Show alert and try again.
        var bundle = this.dialogElement("strings");
        var msg = bundle.getFormattedString("badApp", [this.dialogElement("otherHandler").getAttribute("path")]);
        var svc = Components.classes["@mozilla.org/embedcomp/prompt-service;1"].getService(Components.interfaces.nsIPromptService);
        svc.alert(this.mDialog, bundle.getString("badApp.title"), msg);

        // Disable the OK button.
        this.mDialog.document.documentElement.getButton("accept").disabled = true;
        this.dialogElement("mode").focus();

        // Clear chosen application.
        this.chosenApp = null;

        // Leave dialog up.
        return false;
      }
    }

    // Remove our web progress listener (a progress dialog will be
    // taking over).
    this.mLauncher.setWebProgressListener(null);

    // saveToDisk and launchWithApplication can return errors in
    // certain circumstances (e.g. The user clicks cancel in the
    // "Save to Disk" dialog. In those cases, we don't want to
    // update the helper application preferences in the RDF file.
    try {
      var needUpdate = this.updateMIMEInfo();

      if (this.dialogElement("save").selected) {
        // If we're using a default download location, create a path
        // for the file to be saved to to pass to |saveToDisk| - otherwise
        // we must ask the user to pick a save name.

#if 0
        var prefs = Components.classes["@mozilla.org/preferences-service;1"].getService(Components.interfaces.nsIPrefBranch);
        var targetFile = null;
        try {
          targetFile = prefs.getComplexValue("browser.download.defaultFolder",
                                             Components.interfaces.nsILocalFile);
          var leafName = this.dialogElement("location").getAttribute("realname");
          // Ensure that we don't overwrite any existing files here.
          targetFile = this.validateLeafName(targetFile, leafName, null);
        }
        catch(e) { }

        this.mLauncher.saveToDisk(targetFile, false);
#endif

        // see @notify
        // we cannot use opener's setTimeout, see bug 420405
        this._saveToDiskTimer = Components.classes["@mozilla.org/timer;1"]
                                          .createInstance(nsITimer);
        this._saveToDiskTimer.initWithCallback(this, 0,
                                               nsITimer.TYPE_ONE_SHOT);
      }
      else
        this.mLauncher.launchWithApplication(null, false);

      // Update user pref for this mime type (if necessary). We do not
      // store anything in the mime type preferences for the ambiguous
      // type application/octet-stream. We do NOT do this for
      // application/x-msdownload since we want users to be able to
      // autodownload these to disk.
      if (needUpdate && this.mLauncher.MIMEInfo.MIMEType != "application/octet-stream")
        this.updateHelperAppPref();
    } catch(e) { }

    // Unhook dialog from this object.
    this.mDialog.dialog = null;

    // Close up dialog by returning true.
    return true;
  },

  // onCancel:
  onCancel: function() {
    // Remove our web progress listener.
    this.mLauncher.setWebProgressListener(null);

    // Cancel app launcher.
    try {
      const NS_BINDING_ABORTED = 0x804b0002;
      this.mLauncher.cancel(NS_BINDING_ABORTED);
    } catch(exception) {
    }

    // Unhook dialog from this object.
    this.mDialog.dialog = null;

    // Close up dialog by returning true.
    return true;
  },

  // dialogElement:  Convenience.
  dialogElement: function(id) {
    return this.mDialog.document.getElementById(id);
  },

  // Retrieve the pretty description from the file
  getFileDisplayName: function getFileDisplayName(file)
  {
#ifdef XP_WIN
    if (file instanceof Components.interfaces.nsILocalFileWin) {
      try {
        return file.getVersionInfoField("FileDescription");
      } catch (e) {}
    }
#endif
#ifdef XP_MACOSX
    if (file instanceof Components.interfaces.nsILocalFileMac) {
      try {
        return file.bundleDisplayName;
      } catch (e) {}
    }
#endif
    return file.leafName;
  },

  // chooseApp:  Open file picker and prompt user for application.
  chooseApp: function() {
#ifdef XP_WIN
    // Protect against the lack of an extension
    var fileExtension = "";
    try {
      fileExtension = this.mLauncher.MIMEInfo.primaryExtension;
    } catch(ex) {
    }

    // Try to use the pretty description of the type, if one is available.
    var typeString = this.mLauncher.MIMEInfo.description;

    if (!typeString) {
      // If there is none, use the extension to
      // identify the file, e.g. "ZIP file"
      if (fileExtension) {
        typeString =
          this.dialogElement("strings").
          getFormattedString("fileType", [fileExtension.toUpperCase()]);
      } else {
        // If we can't even do that, just give up and show the MIME type.
        typeString = this.mLauncher.MIMEInfo.MIMEType;
      }
    }

    var params = {};
    params.title =
      this.dialogElement("strings").getString("chooseAppFilePickerTitle");
    params.description = typeString;
    params.filename    = this.mLauncher.suggestedFileName;
    params.mimeInfo    = this.mLauncher.MIMEInfo;
    params.handlerApp  = null;

    this.mDialog.openDialog("chrome://global/content/appPicker.xul", null,
                            "chrome,modal,centerscreen,titlebar,dialog=yes",
                            params);

    if (params.handlerApp &&
        params.handlerApp.executable &&
        params.handlerApp.executable.isFile()) {
      // Remember the file they chose to run.
      this.chosenApp = params.handlerApp;

#else
    var nsIFilePicker = Components.interfaces.nsIFilePicker;
    var fp = Components.classes["@mozilla.org/filepicker;1"]
                       .createInstance(nsIFilePicker);
    fp.init(this.mDialog,
            this.dialogElement("strings").getString("chooseAppFilePickerTitle"),
            nsIFilePicker.modeOpen);

    fp.appendFilters(nsIFilePicker.filterApps);

    if (fp.show() == nsIFilePicker.returnOK && fp.file) {
      // Remember the file they chose to run.
      var localHandlerApp =
        Components.classes["@mozilla.org/uriloader/local-handler-app;1"].
                   createInstance(Components.interfaces.nsILocalHandlerApp);
      localHandlerApp.executable = fp.file;
      this.chosenApp = localHandlerApp;
#endif

      // Show the "handler" menulist since we have a (user-specified)
      // application now.
      this.dialogElement("modeDeck").setAttribute("selectedIndex", "0");

      // Update dialog.
      var otherHandler = this.dialogElement("otherHandler");
      otherHandler.removeAttribute("hidden");
      otherHandler.setAttribute("path", this.getPath(this.chosenApp.executable));
      otherHandler.label = this.getFileDisplayName(this.chosenApp.executable);
      this.dialogElement("openHandler").selectedIndex = 1;
      this.dialogElement("openHandler").setAttribute("lastSelectedItemID", "otherHandler");

      this.dialogElement("mode").selectedItem = this.dialogElement("open");
    }
    else {
      var openHandler = this.dialogElement("openHandler");
      var lastSelectedID = openHandler.getAttribute("lastSelectedItemID");
      if (!lastSelectedID)
        lastSelectedID = "defaultHandler";
      openHandler.selectedItem = this.dialogElement(lastSelectedID);
    }
  },

  // Turn this on to get debugging messages.
  debug: false,

  // Dump text (if debug is on).
  dump: function( text ) {
    if ( this.debug ) {
      dump( text );
    }
  },

  // dumpObj:
  dumpObj: function( spec ) {
    var val = "<undefined>";
    try {
      val = eval( "this."+spec ).toString();
    } catch( exception ) {
    }
    this.dump( spec + "=" + val + "\n" );
  },

  // dumpObjectProperties
  dumpObjectProperties: function( desc, obj ) {
    for( prop in obj ) {
      this.dump( desc + "." + prop + "=" );
      var val = "<undefined>";
      try {
        val = obj[ prop ];
      } catch ( exception ) {
      }
      this.dump( val + "\n" );
    }
  }
}

var NSGetFactory = XPCOMUtils.generateNSGetFactory([nsUnknownContentTypeDialog]);