text: // Copyright 2005 The Closure Library Authors. All Rights Reserved.
  //
  // Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS-IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  /**
   * @fileoverview Utilties for working with DOM nodes related to rich text
   * editing.  Many of these are not general enough to go into goog.dom.
   */
  
  goog.provide('goog.editor.node');
  
  goog.require('goog.dom');
  goog.require('goog.dom.NodeType');
  goog.require('goog.dom.TagName');
  goog.require('goog.dom.iter.ChildIterator');
  goog.require('goog.dom.iter.SiblingIterator');
  goog.require('goog.iter');
  goog.require('goog.object');
  goog.require('goog.string');
  goog.require('goog.string.Unicode');
  goog.require('goog.userAgent');
  
  
  /**
   * Names of all block-level tags
   * @type {Object}
   * @private
   */
  goog.editor.node.BLOCK_TAG_NAMES_ = goog.object.createSet(
      goog.dom.TagName.ADDRESS, goog.dom.TagName.ARTICLE, goog.dom.TagName.ASIDE,
      goog.dom.TagName.BLOCKQUOTE, goog.dom.TagName.BODY,
      goog.dom.TagName.CAPTION, goog.dom.TagName.CENTER, goog.dom.TagName.COL,
      goog.dom.TagName.COLGROUP, goog.dom.TagName.DETAILS, goog.dom.TagName.DIR,
      goog.dom.TagName.DIV, goog.dom.TagName.DL, goog.dom.TagName.DD,
      goog.dom.TagName.DT, goog.dom.TagName.FIELDSET, goog.dom.TagName.FIGCAPTION,
      goog.dom.TagName.FIGURE, goog.dom.TagName.FOOTER, goog.dom.TagName.FORM,
      goog.dom.TagName.H1, goog.dom.TagName.H2, goog.dom.TagName.H3,
      goog.dom.TagName.H4, goog.dom.TagName.H5, goog.dom.TagName.H6,
      goog.dom.TagName.HEADER, goog.dom.TagName.HGROUP, goog.dom.TagName.HR,
      goog.dom.TagName.ISINDEX, goog.dom.TagName.OL, goog.dom.TagName.LI,
      goog.dom.TagName.MAIN, goog.dom.TagName.MAP, goog.dom.TagName.MENU,
      goog.dom.TagName.NAV, goog.dom.TagName.OPTGROUP, goog.dom.TagName.OPTION,
      goog.dom.TagName.P, goog.dom.TagName.PRE, goog.dom.TagName.SECTION,
      goog.dom.TagName.SUMMARY, goog.dom.TagName.TABLE, goog.dom.TagName.TBODY,
      goog.dom.TagName.TD, goog.dom.TagName.TFOOT, goog.dom.TagName.TH,
      goog.dom.TagName.THEAD, goog.dom.TagName.TR, goog.dom.TagName.UL);
  
  
  /**
   * Names of tags that have intrinsic content.
   * TODO(user): What about object, br, input, textarea, button, isindex,
   * hr, keygen, select, table, tr, td?
   * @type {Object}
   * @private
   */
  goog.editor.node.NON_EMPTY_TAGS_ = goog.object.createSet(
      goog.dom.TagName.IMG, goog.dom.TagName.IFRAME, goog.dom.TagName.EMBED);
  
  
  /**
   * Check if the node is in a standards mode document.
   * @param {Node} node The node to test.
   * @return {boolean} Whether the node is in a standards mode document.
   */
  goog.editor.node.isStandardsMode = function(node) {
    return goog.dom.getDomHelper(node).isCss1CompatMode();
  };
  
  
  /**
   * Get the right-most non-ignorable leaf node of the given node.
   * @param {Node} parent The parent ndoe.
   * @return {Node} The right-most non-ignorable leaf node.
   */
  goog.editor.node.getRightMostLeaf = function(parent) {
    var temp;
    while (temp = goog.editor.node.getLastChild(parent)) {
      parent = temp;
    }
    return parent;
  };
  
  
  /**
   * Get the left-most non-ignorable leaf node of the given node.
   * @param {Node} parent The parent ndoe.
   * @return {Node} The left-most non-ignorable leaf node.
   */
  goog.editor.node.getLeftMostLeaf = function(parent) {
    var temp;
    while (temp = goog.editor.node.getFirstChild(parent)) {
      parent = temp;
    }
    return parent;
  };
  
  
  /**
   * Version of firstChild that skips nodes that are entirely
   * whitespace and comments.
   * @param {Node} parent The reference node.
   * @return {Node} The first child of sibling that is important according to
   *     goog.editor.node.isImportant, or null if no such node exists.
   */
  goog.editor.node.getFirstChild = function(parent) {
    return goog.editor.node.getChildHelper_(parent, false);
  };
  
  
  /**
   * Version of lastChild that skips nodes that are entirely whitespace or
   * comments.  (Normally lastChild is a property of all DOM nodes that gives the
   * last of the nodes contained directly in the reference node.)
   * @param {Node} parent The reference node.
   * @return {Node} The last child of sibling that is important according to
   *     goog.editor.node.isImportant, or null if no such node exists.
   */
  goog.editor.node.getLastChild = function(parent) {
    return goog.editor.node.getChildHelper_(parent, true);
  };
  
  
  /**
   * Version of previoussibling that skips nodes that are entirely
   * whitespace or comments.  (Normally previousSibling is a property
   * of all DOM nodes that gives the sibling node, the node that is
   * a child of the same parent, that occurs immediately before the
   * reference node.)
   * @param {Node} sibling The reference node.
   * @return {Node} The closest previous sibling to sibling that is
   *     important according to goog.editor.node.isImportant, or null if no such
   *     node exists.
   */
  goog.editor.node.getPreviousSibling = function(sibling) {
    return /** @type {Node} */ (
        goog.editor.node.getFirstValue_(
            goog.iter.filter(
                new goog.dom.iter.SiblingIterator(sibling, false, true),
                goog.editor.node.isImportant)));
  };
  
  
  /**
   * Version of nextSibling that skips nodes that are entirely whitespace or
   * comments.
   * @param {Node} sibling The reference node.
   * @return {Node} The closest next sibling to sibling that is important
   *     according to goog.editor.node.isImportant, or null if no
   *     such node exists.
   */
  goog.editor.node.getNextSibling = function(sibling) {
    return /** @type {Node} */ (
        goog.editor.node.getFirstValue_(
            goog.iter.filter(
                new goog.dom.iter.SiblingIterator(sibling),
                goog.editor.node.isImportant)));
  };
  
  
  /**
   * Internal helper for lastChild/firstChild that skips nodes that are entirely
   * whitespace or comments.
   * @param {Node} parent The reference node.
   * @param {boolean} isReversed Whether children should be traversed forward
   *     or backward.
   * @return {Node} The first/last child of sibling that is important according
   *     to goog.editor.node.isImportant, or null if no such node exists.
   * @private
   */
  goog.editor.node.getChildHelper_ = function(parent, isReversed) {
    return (!parent || parent.nodeType != goog.dom.NodeType.ELEMENT) ?
        null :
        /** @type {Node} */ (
            goog.editor.node.getFirstValue_(
                goog.iter.filter(
                    new goog.dom.iter.ChildIterator(
                        /** @type {!Element} */ (parent), isReversed),
                    goog.editor.node.isImportant)));
  };
  
  
  /**
   * Utility function that returns the first value from an iterator or null if
   * the iterator is empty.
   * @param {goog.iter.Iterator} iterator The iterator to get a value from.
   * @return {*} The first value from the iterator.
   * @private
   */
  goog.editor.node.getFirstValue_ = function(iterator) {
  
    try {
      return iterator.next();
    } catch (e) {
      return null;
    }
  };
  
  
  /**
   * Determine if a node should be returned by the iterator functions.
   * @param {Node} node An object implementing the DOM1 Node interface.
   * @return {boolean} Whether the node is an element, or a text node that
   *     is not all whitespace.
   */
  goog.editor.node.isImportant = function(node) {
    // Return true if the node is not either a TextNode or an ElementNode.
    return node.nodeType == goog.dom.NodeType.ELEMENT ||
        node.nodeType == goog.dom.NodeType.TEXT &&
        !goog.editor.node.isAllNonNbspWhiteSpace(node);
  };
  
  
  /**
   * Determine whether a node's text content is entirely whitespace.
   * @param {Node} textNode A node implementing the CharacterData interface (i.e.,
   *     a Text, Comment, or CDATASection node.
   * @return {boolean} Whether the text content of node is whitespace,
   *     otherwise false.
   */
  goog.editor.node.isAllNonNbspWhiteSpace = function(textNode) {
    return goog.string.isBreakingWhitespace(textNode.nodeValue);
  };
  
  
  /**
   * Returns true if the node contains only whitespace and is not and does not
   * contain any images, iframes or embed tags.
   * @param {Node} node The node to check.
   * @param {boolean=} opt_prohibitSingleNbsp By default, this function treats a
   *     single nbsp as empty.  Set this to true to treat this case as non-empty.
   * @return {boolean} Whether the node contains only whitespace.
   * @suppress {strictMissingProperties} Part of the go/strict_warnings_migration
   */
  goog.editor.node.isEmpty = function(node, opt_prohibitSingleNbsp) {
    var nodeData = goog.dom.getRawTextContent(node);
  
    if (node.getElementsByTagName) {
      node = /** @type {!Element} */ (node);
      for (var tag in goog.editor.node.NON_EMPTY_TAGS_) {
        if (node.tagName == tag || node.getElementsByTagName(tag).length > 0) {
          return false;
        }
      }
    }
    return (!opt_prohibitSingleNbsp && nodeData == goog.string.Unicode.NBSP) ||
        goog.string.isBreakingWhitespace(nodeData);
  };
  
  
  /**
   * Returns the length of the text in node if it is a text node, or the number
   * of children of the node, if it is an element. Useful for range-manipulation
   * code where you need to know the offset for the right side of the node.
   * @param {Node} node The node to get the length of.
   * @return {number} The length of the node.
   * @suppress {strictMissingProperties} Part of the go/strict_warnings_migration
   */
  goog.editor.node.getLength = function(node) {
    return node.length || node.childNodes.length;
  };
  
  
  /**
   * Search child nodes using a predicate function and return the first node that
   * satisfies the condition.
   * @param {Node} parent The parent node to search.
   * @param {function(Node):boolean} hasProperty A function that takes a child
   *    node as a parameter and returns true if it meets the criteria.
   * @return {?number} The index of the node found, or null if no node is found.
   */
  goog.editor.node.findInChildren = function(parent, hasProperty) {
    for (var i = 0, len = parent.childNodes.length; i < len; i++) {
      if (hasProperty(parent.childNodes[i])) {
        return i;
      }
    }
    return null;
  };
  
  
  /**
   * Search ancestor nodes using a predicate function and returns the topmost
   * ancestor in the chain of consecutive ancestors that satisfies the condition.
   *
   * @param {Node} node The node whose ancestors have to be searched.
   * @param {function(Node): boolean} hasProperty A function that takes a parent
   *     node as a parameter and returns true if it meets the criteria.
   * @return {Node} The topmost ancestor or null if no ancestor satisfies the
   *     predicate function.
   */
  goog.editor.node.findHighestMatchingAncestor = function(node, hasProperty) {
    var parent = node.parentNode;
    var ancestor = null;
    while (parent && hasProperty(parent)) {
      ancestor = parent;
      parent = parent.parentNode;
    }
    return ancestor;
  };
  
  
  /**
  * Checks if node is a block-level html element. The <tt>display</tt> css
   * property is ignored.
   * @param {Node} node The node to test.
   * @return {boolean} Whether the node is a block-level node.
   */
  goog.editor.node.isBlockTag = function(node) {
    return !!goog.editor.node.BLOCK_TAG_NAMES_[
        /** @type {!Element} */ (node).tagName];
  };
  
  
  /**
   * Skips siblings of a node that are empty text nodes.
   * @param {Node} node A node. May be null.
   * @return {Node} The node or the first sibling of the node that is not an
   *     empty text node. May be null.
   */
  goog.editor.node.skipEmptyTextNodes = function(node) {
    while (node && node.nodeType == goog.dom.NodeType.TEXT && !node.nodeValue) {
      node = node.nextSibling;
    }
    return node;
  };
  
  
  /**
   * Checks if an element is a top-level editable container (meaning that
   * it itself is not editable, but all its child nodes are editable).
   * @param {Node} element The element to test.
   * @return {boolean} Whether the element is a top-level editable container.
   * @suppress {strictMissingProperties} Part of the go/strict_warnings_migration
   */
  goog.editor.node.isEditableContainer = function(element) {
    return element.getAttribute && element.getAttribute('g_editable') == 'true';
  };
  
  
  /**
   * Checks if a node is inside an editable container.
   * @param {Node} node The node to test.
   * @return {boolean} Whether the node is in an editable container.
   */
  goog.editor.node.isEditable = function(node) {
    return !!goog.dom.getAncestor(node, goog.editor.node.isEditableContainer);
  };
  
  
  /**
   * Finds the top-most DOM node inside an editable field that is an ancestor
   * (or self) of a given DOM node and meets the specified criteria.
   * @param {Node} node The DOM node where the search starts.
   * @param {function(Node) : boolean} criteria A function that takes a DOM node
   *     as a parameter and returns a boolean to indicate whether the node meets
   *     the criteria or not.
   * @return {Node} The DOM node if found, or null.
   */
  goog.editor.node.findTopMostEditableAncestor = function(node, criteria) {
    var targetNode = null;
    while (node && !goog.editor.node.isEditableContainer(node)) {
      if (criteria(node)) {
        targetNode = node;
      }
      node = node.parentNode;
    }
    return targetNode;
  };
  
  
  /**
   * Splits off a subtree.
   * @param {!Node} currentNode The starting splitting point.
   * @param {Node=} opt_secondHalf The initial leftmost leaf the new subtree.
   *     If null, siblings after currentNode will be placed in the subtree, but
   *     no additional node will be.
   * @param {Node=} opt_root The top of the tree where splitting stops at.
   * @return {!Node} The new subtree.
   */
  goog.editor.node.splitDomTreeAt = function(
      currentNode, opt_secondHalf, opt_root) {
    var parent;
    while (currentNode != opt_root && (parent = currentNode.parentNode)) {
      opt_secondHalf = goog.editor.node.getSecondHalfOfNode_(
          parent, currentNode, opt_secondHalf);
      currentNode = parent;
    }
    return /** @type {!Node} */ (opt_secondHalf);
  };
  
  
  /**
   * Creates a clone of node, moving all children after startNode to it.
   * When firstChild is not null or undefined, it is also appended to the clone
   * as the first child.
   * @param {!Node} node The node to clone.
   * @param {!Node} startNode All siblings after this node will be moved to the
   *     clone.
   * @param {Node|undefined} firstChild The first child of the new cloned element.
   * @return {!Node} The cloned node that now contains the children after
   *     startNode.
   * @private
   */
  goog.editor.node.getSecondHalfOfNode_ = function(node, startNode, firstChild) {
    var secondHalf = /** @type {!Node} */ (node.cloneNode(false));
    while (startNode.nextSibling) {
      goog.dom.appendChild(secondHalf, startNode.nextSibling);
    }
    if (firstChild) {
      secondHalf.insertBefore(firstChild, secondHalf.firstChild);
    }
    return secondHalf;
  };
  
  
  /**
   * Appends all of oldNode's children to newNode. This removes all children from
   * oldNode and appends them to newNode. oldNode is left with no children.
   * @param {!Node} newNode Node to transfer children to.
   * @param {Node} oldNode Node to transfer children from.
   * @deprecated Use goog.dom.append directly instead.
   */
  goog.editor.node.transferChildren = function(newNode, oldNode) {
    goog.dom.append(newNode, oldNode.childNodes);
  };
  
  
  /**
   * Replaces the innerHTML of a node.
   *
   * IE has serious problems if you try to set innerHTML of an editable node with
   * any selection. Early versions of IE tear up the old internal tree storage, to
   * help avoid ref-counting loops. But this sometimes leaves the selection object
   * in a bad state and leads to segfaults.
   *
   * Removing the nodes first prevents IE from tearing them up. This is not
   * strictly necessary in nodes that do not have the selection. You should always
   * use this function when setting innerHTML inside of a field.
   * @param {Node} node A node.
   * @param {string} html The innerHTML to set on the node.
   * @suppress {strictMissingProperties} Part of the go/strict_warnings_migration
   */
  goog.editor.node.replaceInnerHtml = function(node, html) {
    // Only do this IE. On gecko, we use element change events, and don't
    // want to trigger spurious events.
    if (goog.userAgent.IE) {
      goog.dom.removeChildren(node);
    }
    node.innerHTML = html;
  };
  