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// Copyright 2008 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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 * @fileoverview Editor plugin to handle tab keys not in lists to add 4 spaces.
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 *
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 * @author [email protected] (Robby Walker)
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 */
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goog.provide('goog.editor.plugins.SpacesTabHandler');
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goog.require('goog.dom.TagName');
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goog.require('goog.editor.plugins.AbstractTabHandler');
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goog.require('goog.editor.range');
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/**
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 * Plugin to handle tab keys when not in lists to add 4 spaces.
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 * @constructor
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 * @extends {goog.editor.plugins.AbstractTabHandler}
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 * @final
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 */
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goog.editor.plugins.SpacesTabHandler = function() {
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  goog.editor.plugins.AbstractTabHandler.call(this);
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};
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goog.inherits(
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    goog.editor.plugins.SpacesTabHandler,
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    goog.editor.plugins.AbstractTabHandler);
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/** @override */
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goog.editor.plugins.SpacesTabHandler.prototype.getTrogClassId = function() {
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  return 'SpacesTabHandler';
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};
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/** @override */
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goog.editor.plugins.SpacesTabHandler.prototype.handleTabKey = function(e) {
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  var dh = this.getFieldDomHelper();
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  var range = this.getFieldObject().getRange();
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  if (!goog.editor.range.intersectsTag(range, goog.dom.TagName.LI)) {
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    // In the shift + tab case we don't want to insert spaces, but we don't
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    // want focus to move either so skip the spacing logic and just prevent
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    // default.
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    if (!e.shiftKey) {
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      // Not in a list but we want to insert 4 spaces.
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      // Stop change events while we make multiple field changes.
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      this.getFieldObject().stopChangeEvents(true, true);
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      // Inserting nodes below completely messes up the selection, doing the
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      // deletion here before it's messed up. Only delete if text is selected,
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      // otherwise we would remove the character to the right of the cursor.
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      if (!range.isCollapsed()) {
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        dh.getDocument().execCommand('delete', false, null);
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        // Safari 3 has some DOM exceptions if we don't reget the range here,
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        // doing it all the time just to be safe.
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        range = this.getFieldObject().getRange();
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      }
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      // Emulate tab by removing selection and inserting 4 spaces
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      // Two breaking spaces in a row can be collapsed by the browser into one
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      // space. Inserting the string below because it is guaranteed to never
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      // collapse to less than four spaces, regardless of what is adjacent to
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      // the inserted spaces. This might make line wrapping slightly
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      // sub-optimal around a grouping of non-breaking spaces.
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      var elem =
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          dh.createDom(goog.dom.TagName.SPAN, null, '\u00a0\u00a0 \u00a0');
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      elem = range.insertNode(elem, false);
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      this.getFieldObject().dispatchChange();
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      goog.editor.range.placeCursorNextTo(elem, false);
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      this.getFieldObject().dispatchSelectionChangeEvent();
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    }
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    e.preventDefault();
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    return true;
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  }
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  return false;
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};
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