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// Copyright 2007 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 DOM patterns.  Allows for description of complex DOM patterns
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 * using regular expression like constructs.
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 *
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 * @author [email protected] (Robby Walker)
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 */
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goog.provide('goog.dom.pattern');
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goog.provide('goog.dom.pattern.MatchType');
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/**
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 * Utility function to match a string against either a string or a regular
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 * expression.
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 *
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 * @param {string|RegExp} obj Either a string or a regular expression.
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 * @param {string} str The string to match.
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 * @return {boolean} Whether the strings are equal, or if the string matches
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 *     the regular expression.
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 */
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goog.dom.pattern.matchStringOrRegex = function(obj, str) {
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  if (goog.isString(obj)) {
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    // Match a string
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    return str == obj;
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  } else {
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    // Match a regular expression
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    return !!(str && str.match(obj));
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  }
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};
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/**
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 * Utility function to match a DOM attribute against either a string or a
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 * regular expression.  Conforms to the interface spec for
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 * {@link goog.object#every}.
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 *
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 * @param {string|RegExp} elem Either a string or a regular expression.
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 * @param {string} index The attribute name to match.
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 * @param {Object} orig The original map of matches to test.
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 * @return {boolean} Whether the strings are equal, or if the attribute matches
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 *     the regular expression.
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 * @this {Element} Called using goog.object every on an Element.
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 */
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goog.dom.pattern.matchStringOrRegexMap = function(elem, index, orig) {
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  return goog.dom.pattern.matchStringOrRegex(
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      elem, index in this ?
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          this[index] :
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          (this.getAttribute ? this.getAttribute(index) : null));
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};
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/**
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 * When matched to a token, a pattern may return any of the following statuses:
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 *  <ol>
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 *    <li><code>NO_MATCH</code> - The pattern does not match.  This is the only
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 *      value that evaluates to <code>false</code> in a boolean context.
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 *    <li><code>MATCHING</code> - The token is part of an incomplete match.
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 *    <li><code>MATCH</code> - The token completes a match.
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 *    <li><code>BACKTRACK_MATCH</code> - The token does not match, but indicates
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 *      the end of a repetitive match.  For instance, in regular expressions,
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 *      the pattern <code>/a+/</code> would match <code>'aaaaaaaab'</code>.
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 *      Every <code>'a'</code> token would give a status of
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 *      <code>MATCHING</code> while the <code>'b'</code> token would give a
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 *      status of <code>BACKTRACK_MATCH</code>.
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 *  </ol>
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 * @enum {number}
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 */
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goog.dom.pattern.MatchType = {
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  NO_MATCH: 0,
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  MATCHING: 1,
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  MATCH: 2,
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  BACKTRACK_MATCH: 3
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};
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