gecko/browser/components/preferences/feeds.js

# -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
# ***** 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 the Firefox Preferences System.
#
# The Initial Developer of the Original Code is
# Jeff Walden <jwalden+code@mit.edu>.
# Portions created by the Initial Developer are Copyright (C) 2006
# the Initial Developer. All Rights Reserved.
#
# Contributor(s):
#   Asaf Romano <mozilla.mano@sent.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
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# the provisions above, a recipient may use your version of this file under
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#ifndef XP_MACOSX
var Cc = Components.classes;
var Ci = Components.interfaces;
var Cr = Components.results;
var TYPE_MAYBE_FEED = "application/vnd.mozilla.maybe.feed";
const kXULNS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
#endif

/*
 * Preferences:
 *
 * browser.feeds.handler
 * - "bookmarks", "reader" (clarified further using the .default preference),
 *   or "ask" -- indicates the default handler being used to process feeds
 *
 * browser.feeds.handler.default
 * - "bookmarks", "client" or "web" -- indicates the chosen feed reader used
 *   to display feeds, either transiently (i.e., when the "use as default"
 *   checkbox is unchecked, corresponds to when browser.feeds.handler=="ask")
 *   or more permanently (i.e., the item displayed in the dropdown in Feeds
 *   preferences)
 *
 * browser.feeds.handler.webservice
 * - the URL of the currently selected web service used to read feeds
 *
 * browser.feeds.handlers.application
 * - nsILocalFile, stores the current client-side feed reading app if one has
 *   been chosen
 */
   
const PREF_SELECTED_APP    = "browser.feeds.handlers.application";
const PREF_SELECTED_WEB    = "browser.feeds.handlers.webservice";
const PREF_SELECTED_ACTION = "browser.feeds.handler";
const PREF_SELECTED_READER = "browser.feeds.handler.default";

var gFeedsPane = {
  element: function(aID) {
    return document.getElementById(aID);
  },

  /* ........ QueryInterface .............. */
  QueryInterface: function(aIID) {
    if (aIID.equals(Ci.nsISupports) ||
        aIID.equals(Ci.nsIObserver) ||
        aIID.equals(Ci.nsIDOMEventListener))
      return this;
      
    throw Cr.NS_ERROR_NO_INTERFACE;
  },

  /**
   * See nsIObserver
   */
  observe: function(aSubject, aTopic, aData) {
    if (aTopic != "nsPref:changed" || aData != PREF_SELECTED_WEB)
      return;

    if (this.element(PREF_SELECTED_ACTION).value == "reader") {
      var wccr = 
        Cc["@mozilla.org/embeddor.implemented/web-content-handler-registrar;1"].
        getService(Ci.nsIWebContentConverterService);
      var handlerURL = this.element(PREF_SELECTED_WEB).valueFromPreferences;
      var handler =
        wccr.getWebContentHandlerByURI(TYPE_MAYBE_FEED, handlerURL);
      if (handler)
        wccr.setAutoHandler(TYPE_MAYBE_FEED, handler);
    }
  },

  /**
   * See nsIDOMEventListener
   */
  handleEvent: function(aEvent) {
    if (aEvent.type == "unload") {
      var prefBranch = Cc["@mozilla.org/preferences-service;1"].
        getService(Ci.nsIPrefBranch2);
      prefBranch.removeObserver(PREF_SELECTED_WEB, this);
      window.removeEventListener("unload", this, false);
    }
  },

  /**
   * Initializes this.
   */
  init: function () {
    var _delayedPaneLoad = function(self) {
      self._initFeedReaders();
      self.updateSelectedReader();
    }
    setTimeout(_delayedPaneLoad, 0, this);

    // For web readers, we need to call setAutoHandler if the
    // preview page should be skipped (i.e. PREF_SELECTED_ACTION="reader")
    // To do so, we've to add a pref-observer in order to be notified on
    // actual pref-changes (i.e. not on pref changes which may not take
    // affect when the prefwindow is closed)
    var prefBranch = Cc["@mozilla.org/preferences-service;1"].
      getService(Ci.nsIPrefBranch2);

    prefBranch.addObserver(PREF_SELECTED_WEB, this, false);
    window.addEventListener("unload", this, false);
  },

  /**
   * Populates the UI list of available feed readers.
   */
  _initFeedReaders: function() {
    this.updateSelectedApplicationInfo();

    var readersList = this.element("readers");

    // List the system default feed reader if it is
    // not the last-selected application already
    try {
      var systemDefaultReader = Cc["@mozilla.org/browser/shell-service;1"].
                                getService(Ci.nsIShellService).
                                defaultFeedReader;

      var defaultSystemReaderFilefield = this.element("defaultSystemReaderFilefield");
      defaultSystemReaderFilefield.file = systemDefaultReader;
      var selectedAppFile = this.element("selectedAppFilefield").file;
      if (!selectedAppFile || defaultSystemReaderFilefield.file.path !=
          selectedAppFile.path) {
        var defaultReaderItem = document.createElementNS(kXULNS, "listitem");
        defaultReaderItem.id = "defaultSystemReaderListitem";
        defaultReaderItem.className = "listitem-iconic";
        defaultReaderItem.setAttribute("label", defaultSystemReaderFilefield.label);
        defaultReaderItem.setAttribute("image", defaultSystemReaderFilefield.image);
        readersList.appendChild(defaultReaderItem);
      }
    }
    catch(ex) { /* no default reader */ }

    // List of web handlers
    var wccr = 
        Cc["@mozilla.org/embeddor.implemented/web-content-handler-registrar;1"].
        getService(Ci.nsIWebContentConverterService);
    var handlers = wccr.getContentHandlers(TYPE_MAYBE_FEED, {});
    if (handlers.length == 0)
      return;

    var ios = 
        Cc["@mozilla.org/network/io-service;1"].
        getService(Ci.nsIIOService);
    for (var i = 0; i < handlers.length; ++i) {
      var row = document.createElementNS(kXULNS, "listitem");
      row.className = "listitem-iconic";
      row.setAttribute("label", handlers[i].name);
      row.setAttribute("webhandlerurl", handlers[i].uri);

      var uri = ios.newURI(handlers[i].uri, null, null);
      if (/^https?/.test(uri.scheme))
        row.setAttribute("image", uri.prePath + "/favicon.ico");

      readersList.appendChild(row);
    }
  },

  /**
   * Updates the label and image of the client feed reader listitem
   */
  updateSelectedApplicationInfo: function() {
    var appItemCell = this.element("selectedApplicationCell");
    var selectedAppFilefield = this.element("selectedAppFilefield");
    selectedAppFilefield.file = this.element(PREF_SELECTED_APP).value;
    if (selectedAppFilefield.file) {
      appItemCell.setAttribute("label", selectedAppFilefield.label);
      appItemCell.setAttribute("image", selectedAppFilefield.image);
    }
    else {
      var noAppString =
        this.element("stringbundle").getString("noApplicationSelected");
      appItemCell.setAttribute("label", noAppString);
      appItemCell.setAttribute("image", "");
    }
  },

  /**
   * Selects a item in the list without triggering a preference change.
   *
   * @param aItem
   *        the listitem to be selected
   */
  _silentSelectReader: function(aItem) {
    var readers = this.element("readers");
    readers.setAttribute("suppressonselect", "true");
    readers.selectItem(aItem);
    readers.removeAttribute("suppressonselect");
  },

  /**
   * Helper for updateSelectedReader. Syncs the selected item in the readers
   * list with value stored invalues stored in PREF_SELECTED_WEB
   */
  _updateSelectedWebHandlerItem: function() {
    // We should select the new web handler only if the default handler
    // is "web"
    var readers = this.element("readers")
    var readerElts =
        readers.getElementsByAttribute("webhandlerurl",
                                       this.element(PREF_SELECTED_WEB).value);

    // XXXmano: handle the addition of a new web handler
    if (readerElts.length > 0)
      this._silentSelectReader(readerElts[0]);
  },

  /**
   * Syncs the selected item in the readers list with the values stored in
   * preferences.
   */
  updateSelectedReader: function() {
    var defaultReader = this.element(PREF_SELECTED_READER).value ||
                        "bookmarks";
    switch (defaultReader) {
      case "bookmarks":
        this._silentSelectReader(this.element("liveBookmarksListItem"));
        break;
      case "client":
#ifdef XP_WIN
        // Keep the system default feed reader item selected if the
        // last-selected application is the the system default feed reader
        // and if it is already selected
        var currentItem = this.element("readers").currentItem;
        if (currentItem && currentItem.id == "defaultSystemReaderListitem") {
          var defaultSystemReaderFile = this.element("defaultSystemReaderFilefield").file;
          var selectedAppFile = this.element("selectedAppFilefield").file;
          if (selectedAppFile && defaultSystemReaderFile &&
              defaultSystemReaderFile.path == selectedAppFile.path)
            break;
        }
#endif

        this._silentSelectReader(this.element("selectedApplicationListitem"));
        break;
      case "web":
        this._updateSelectedWebHandlerItem();
        break;
    }
  },

  /**
   * Displays a prompt from which the user may choose an a (client) feed reader.
   */
  chooseClientApp: function () {
    var fp = Cc["@mozilla.org/filepicker;1"]
               .createInstance(Ci.nsIFilePicker);
    fp.init(window, document.title, Ci.nsIFilePicker.modeOpen);
    fp.appendFilters(Ci.nsIFilePicker.filterApps);
    if (fp.show() == Ci.nsIFilePicker.returnOK && fp.file) {
      // XXXben - we need to compare this with the running instance executable
      //          just don't know how to do that via script...
      // XXXmano TBD: can probably add this to nsIShellService
#ifdef XP_WIN
#expand       if (fp.file.leafName == "__MOZ_APP_NAME__.exe")
#else
#ifdef XP_MACOSX
#expand       if (fp.file.leafName == "__MOZ_APP_DISPLAYNAME__.app")
#else
#expand       if (fp.file.leafName == "__MOZ_APP_NAME__-bin")
#endif
#endif
        return;

      this.element(PREF_SELECTED_APP).value = fp.file;
      this.element(PREF_SELECTED_READER).value = "client";
    }
  },

  /**
   * Disables the readers list if "Show preview..." is selected, enables
   * it otherwise.
   */
  onReadingMethodSelect: function() {
    var disableList = this.element("readingMethod").value == "ask";
    this.element("readers").disabled = disableList;
    this.element("chooseClientApp").disabled = disableList;
  },

  /**
   * Maps the value of PREF_SELECTED_ACTION to the parallel
   * value in the radiogroup
   */
  onReadingMethodSyncFromPreference: function() {
    var pref = this.element(PREF_SELECTED_ACTION);
    var newVal = pref.instantApply ? pref.valueFromPreferences : pref.value;
    if (newVal != "ask")
      return "reader";

    return "ask";
  },

  /**
   * Returns the value to be used for PREF_SELECTED_ACTION
   * according to the current UI state.
   */
  onReadingMethodSyncToPreference: function() {
    var readers = this.element("readers");

    // A reader must be choosed in order to skip the preview page
    if (this.element("readingMethod").value == "ask" ||
        !readers.currentItem)
      return "ask";

    if (readers.currentItem.id == "liveBookmarksListItem")
      return "bookmarks";

    return "reader";
  },

  /**
   * Syncs PREF_SELECTED_READER with the selected item in the readers list
   * Also updates PREF_SELECTED_ACTION if necessary
   */
  writeSelectedFeedReader: function() {
    // Force update of the action pref. This is needed for the case in which
    // the user flipped from a reader to live bookmarks or vice-versa
    this.element(PREF_SELECTED_ACTION).value =
      this.onReadingMethodSyncToPreference();

    var currentItem = this.element("readers").currentItem;
    if (currentItem.hasAttribute("webhandlerurl")) {
      this.element(PREF_SELECTED_WEB).value =
        currentItem.getAttribute("webhandlerurl");
      this.element(PREF_SELECTED_READER).value = "web";
    }
    else {
      switch (currentItem.id) {
        case "liveBookmarksListItem":
          this.element(PREF_SELECTED_READER).value = "bookmarks";
          break;
        case "selectedApplicationListitem":
          // PREF_SELECTED_APP is saved in chooseClientApp
          this.element(PREF_SELECTED_READER).value = "client";
          break;
#ifdef XP_WIN
        case "defaultSystemReaderListitem":
          this.element(PREF_SELECTED_APP).value = this.element("defaultSystemReaderFilefield").file;
          this.element(PREF_SELECTED_READER).value = "client";
          break;
#endif
      }
    }
  }
};