text: // Copyright 2006 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 Rendering engine detection.
   * @see <a href="http://www.useragentstring.com/">User agent strings</a>
   * For information on the browser brand (such as Safari versus Chrome), see
   * goog.userAgent.product.
   * @see ../demos/useragent.html
   */
  
  goog.provide('goog.userAgent');
  
  goog.require('goog.string');
  
  
  /**
   * @define {boolean} Whether we know at compile-time that the browser is IE.
   */
  goog.userAgent.ASSUME_IE = false;
  
  
  /**
   * @define {boolean} Whether we know at compile-time that the browser is GECKO.
   */
  goog.userAgent.ASSUME_GECKO = false;
  
  
  /**
   * @define {boolean} Whether we know at compile-time that the browser is WEBKIT.
   */
  goog.userAgent.ASSUME_WEBKIT = false;
  
  
  /**
   * @define {boolean} Whether we know at compile-time that the browser is a
   *     mobile device running WebKit e.g. iPhone or Android.
   */
  goog.userAgent.ASSUME_MOBILE_WEBKIT = false;
  
  
  /**
   * @define {boolean} Whether we know at compile-time that the browser is OPERA.
   */
  goog.userAgent.ASSUME_OPERA = false;
  
  
  /**
   * @define {boolean} Whether the {@code goog.userAgent.isVersion} function will
   *     return true for any version.
   */
  goog.userAgent.ASSUME_ANY_VERSION = false;
  
  
  /**
   * Whether we know the browser engine at compile-time.
   * @type {boolean}
   * @private
   */
  goog.userAgent.BROWSER_KNOWN_ =
      goog.userAgent.ASSUME_IE ||
      goog.userAgent.ASSUME_GECKO ||
      goog.userAgent.ASSUME_MOBILE_WEBKIT ||
      goog.userAgent.ASSUME_WEBKIT ||
      goog.userAgent.ASSUME_OPERA;
  
  
  /**
   * Returns the userAgent string for the current browser.
   * Some user agents (I'm thinking of you, Gears WorkerPool) do not expose a
   * navigator object off the global scope.  In that case we return null.
   *
   * @return {?string} The userAgent string or null if there is none.
   */
  goog.userAgent.getUserAgentString = function() {
    return goog.global['navigator'] ? goog.global['navigator'].userAgent : null;
  };
  
  
  /**
   * @return {Object} The native navigator object.
   */
  goog.userAgent.getNavigator = function() {
    // Need a local navigator reference instead of using the global one,
    // to avoid the rare case where they reference different objects.
    // (in a WorkerPool, for example).
    return goog.global['navigator'];
  };
  
  
  /**
   * Initializer for goog.userAgent.
   *
   * This is a named function so that it can be stripped via the jscompiler
   * option for stripping types.
   * @private
   */
  goog.userAgent.init_ = function() {
    /**
     * Whether the user agent string denotes Opera.
     * @type {boolean}
     * @private
     */
    goog.userAgent.detectedOpera_ = false;
  
    /**
     * Whether the user agent string denotes Internet Explorer. This includes
     * other browsers using Trident as its rendering engine. For example AOL
     * and Netscape 8
     * @type {boolean}
     * @private
     */
    goog.userAgent.detectedIe_ = false;
  
    /**
     * Whether the user agent string denotes WebKit. WebKit is the rendering
     * engine that Safari, Android and others use.
     * @type {boolean}
     * @private
     */
    goog.userAgent.detectedWebkit_ = false;
  
    /**
     * Whether the user agent string denotes a mobile device.
     * @type {boolean}
     * @private
     */
    goog.userAgent.detectedMobile_ = false;
  
    /**
     * Whether the user agent string denotes Gecko. Gecko is the rendering
     * engine used by Mozilla, Mozilla Firefox, Camino and many more.
     * @type {boolean}
     * @private
     */
    goog.userAgent.detectedGecko_ = false;
  
    var ua;
    if (!goog.userAgent.BROWSER_KNOWN_ &&
        (ua = goog.userAgent.getUserAgentString())) {
      var navigator = goog.userAgent.getNavigator();
      goog.userAgent.detectedOpera_ = ua.indexOf('Opera') == 0;
      goog.userAgent.detectedIe_ = !goog.userAgent.detectedOpera_ &&
          ua.indexOf('MSIE') != -1;
      goog.userAgent.detectedWebkit_ = !goog.userAgent.detectedOpera_ &&
          ua.indexOf('WebKit') != -1;
      // WebKit also gives navigator.product string equal to 'Gecko'.
      goog.userAgent.detectedMobile_ = goog.userAgent.detectedWebkit_ &&
          ua.indexOf('Mobile') != -1;
      goog.userAgent.detectedGecko_ = !goog.userAgent.detectedOpera_ &&
          !goog.userAgent.detectedWebkit_ && navigator.product == 'Gecko';
    }
  };
  
  
  if (!goog.userAgent.BROWSER_KNOWN_) {
    goog.userAgent.init_();
  }
  
  
  /**
   * Whether the user agent is Opera.
   * @type {boolean}
   */
  goog.userAgent.OPERA = goog.userAgent.BROWSER_KNOWN_ ?
      goog.userAgent.ASSUME_OPERA : goog.userAgent.detectedOpera_;
  
  
  /**
   * Whether the user agent is Internet Explorer. This includes other browsers
   * using Trident as its rendering engine. For example AOL and Netscape 8
   * @type {boolean}
   */
  goog.userAgent.IE = goog.userAgent.BROWSER_KNOWN_ ?
      goog.userAgent.ASSUME_IE : goog.userAgent.detectedIe_;
  
  
  /**
   * Whether the user agent is Gecko. Gecko is the rendering engine used by
   * Mozilla, Mozilla Firefox, Camino and many more.
   * @type {boolean}
   */
  goog.userAgent.GECKO = goog.userAgent.BROWSER_KNOWN_ ?
      goog.userAgent.ASSUME_GECKO :
      goog.userAgent.detectedGecko_;
  
  
  /**
   * Whether the user agent is WebKit. WebKit is the rendering engine that
   * Safari, Android and others use.
   * @type {boolean}
   */
  goog.userAgent.WEBKIT = goog.userAgent.BROWSER_KNOWN_ ?
      goog.userAgent.ASSUME_WEBKIT || goog.userAgent.ASSUME_MOBILE_WEBKIT :
      goog.userAgent.detectedWebkit_;
  
  
  /**
   * Whether the user agent is running on a mobile device.
   * @type {boolean}
   */
  goog.userAgent.MOBILE = goog.userAgent.ASSUME_MOBILE_WEBKIT ||
                          goog.userAgent.detectedMobile_;
  
  
  /**
   * Used while transitioning code to use WEBKIT instead.
   * @type {boolean}
   * @deprecated Use {@link goog.userAgent.product.SAFARI} instead.
   * TODO(nicksantos): Delete this from goog.userAgent.
   */
  goog.userAgent.SAFARI = goog.userAgent.WEBKIT;
  
  
  /**
   * @return {string} the platform (operating system) the user agent is running
   *     on. Default to empty string because navigator.platform may not be defined
   *     (on Rhino, for example).
   * @private
   */
  goog.userAgent.determinePlatform_ = function() {
    var navigator = goog.userAgent.getNavigator();
    return navigator && navigator.platform || '';
  };
  
  
  /**
   * The platform (operating system) the user agent is running on. Default to
   * empty string because navigator.platform may not be defined (on Rhino, for
   * example).
   * @type {string}
   */
  goog.userAgent.PLATFORM = goog.userAgent.determinePlatform_();
  
  
  /**
   * @define {boolean} Whether the user agent is running on a Macintosh operating
   *     system.
   */
  goog.userAgent.ASSUME_MAC = false;
  
  
  /**
   * @define {boolean} Whether the user agent is running on a Windows operating
   *     system.
   */
  goog.userAgent.ASSUME_WINDOWS = false;
  
  
  /**
   * @define {boolean} Whether the user agent is running on a Linux operating
   *     system.
   */
  goog.userAgent.ASSUME_LINUX = false;
  
  
  /**
   * @define {boolean} Whether the user agent is running on a X11 windowing
   *     system.
   */
  goog.userAgent.ASSUME_X11 = false;
  
  
  /**
   * @type {boolean}
   * @private
   */
  goog.userAgent.PLATFORM_KNOWN_ =
      goog.userAgent.ASSUME_MAC ||
      goog.userAgent.ASSUME_WINDOWS ||
      goog.userAgent.ASSUME_LINUX ||
      goog.userAgent.ASSUME_X11;
  
  
  /**
   * Initialize the goog.userAgent constants that define which platform the user
   * agent is running on.
   * @private
   */
  goog.userAgent.initPlatform_ = function() {
    /**
     * Whether the user agent is running on a Macintosh operating system.
     * @type {boolean}
     * @private
     */
    goog.userAgent.detectedMac_ = goog.string.contains(goog.userAgent.PLATFORM,
        'Mac');
  
    /**
     * Whether the user agent is running on a Windows operating system.
     * @type {boolean}
     * @private
     */
    goog.userAgent.detectedWindows_ = goog.string.contains(
        goog.userAgent.PLATFORM, 'Win');
  
    /**
     * Whether the user agent is running on a Linux operating system.
     * @type {boolean}
     * @private
     */
    goog.userAgent.detectedLinux_ = goog.string.contains(goog.userAgent.PLATFORM,
        'Linux');
  
    /**
     * Whether the user agent is running on a X11 windowing system.
     * @type {boolean}
     * @private
     */
    goog.userAgent.detectedX11_ = !!goog.userAgent.getNavigator() &&
        goog.string.contains(goog.userAgent.getNavigator()['appVersion'] || '',
            'X11');
  };
  
  
  if (!goog.userAgent.PLATFORM_KNOWN_) {
    goog.userAgent.initPlatform_();
  }
  
  
  /**
   * Whether the user agent is running on a Macintosh operating system.
   * @type {boolean}
   */
  goog.userAgent.MAC = goog.userAgent.PLATFORM_KNOWN_ ?
      goog.userAgent.ASSUME_MAC : goog.userAgent.detectedMac_;
  
  
  /**
   * Whether the user agent is running on a Windows operating system.
   * @type {boolean}
   */
  goog.userAgent.WINDOWS = goog.userAgent.PLATFORM_KNOWN_ ?
      goog.userAgent.ASSUME_WINDOWS : goog.userAgent.detectedWindows_;
  
  
  /**
   * Whether the user agent is running on a Linux operating system.
   * @type {boolean}
   */
  goog.userAgent.LINUX = goog.userAgent.PLATFORM_KNOWN_ ?
      goog.userAgent.ASSUME_LINUX : goog.userAgent.detectedLinux_;
  
  
  /**
   * Whether the user agent is running on a X11 windowing system.
   * @type {boolean}
   */
  goog.userAgent.X11 = goog.userAgent.PLATFORM_KNOWN_ ?
      goog.userAgent.ASSUME_X11 : goog.userAgent.detectedX11_;
  
  
  /**
   * @return {string} The string that describes the version number of the user
   *     agent.
   * @private
   */
  goog.userAgent.determineVersion_ = function() {
    // All browsers have different ways to detect the version and they all have
    // different naming schemes.
  
    // version is a string rather than a number because it may contain 'b', 'a',
    // and so on.
    var version = '', re;
  
    if (goog.userAgent.OPERA && goog.global['opera']) {
      var operaVersion = goog.global['opera'].version;
      version = typeof operaVersion == 'function' ? operaVersion() : operaVersion;
    } else {
      if (goog.userAgent.GECKO) {
        re = /rv\:([^\);]+)(\)|;)/;
      } else if (goog.userAgent.IE) {
        re = /MSIE\s+([^\);]+)(\)|;)/;
      } else if (goog.userAgent.WEBKIT) {
        // WebKit/125.4
        re = /WebKit\/(\S+)/;
      }
      if (re) {
        var arr = re.exec(goog.userAgent.getUserAgentString());
        version = arr ? arr[1] : '';
      }
    }
    if (goog.userAgent.IE) {
      // IE9 can be in document mode 9 but be reporting an inconsistent user agent
      // version.  If it is identifying as a version lower than 9 we take the
      // documentMode as the version instead.  IE8 has similar behavior.
      // It is recommended to set the X-UA-Compatible header to ensure that IE9
      // uses documentMode 9.
      var docMode = goog.userAgent.getDocumentMode_();
      if (docMode > parseFloat(version)) {
        return String(docMode);
      }
    }
    return version;
  };
  
  
  /**
   * @return {number|undefined} Returns the document mode (for testing).
   * @private
   */
  goog.userAgent.getDocumentMode_ = function() {
    // NOTE(user): goog.userAgent may be used in context where there is no DOM.
    var doc = goog.global['document'];
    return doc ? doc['documentMode'] : undefined;
  };
  
  
  /**
   * The version of the user agent. This is a string because it might contain
   * 'b' (as in beta) as well as multiple dots.
   * @type {string}
   */
  goog.userAgent.VERSION = goog.userAgent.determineVersion_();
  
  
  /**
   * Compares two version numbers.
   *
   * @param {string} v1 Version of first item.
   * @param {string} v2 Version of second item.
   *
   * @return {number}  1 if first argument is higher
   *                   0 if arguments are equal
   *                  -1 if second argument is higher.
   * @deprecated Use goog.string.compareVersions.
   */
  goog.userAgent.compare = function(v1, v2) {
    return goog.string.compareVersions(v1, v2);
  };
  
  
  /**
   * Cache for {@link goog.userAgent.isVersion}. Calls to compareVersions are
   * surprisingly expensive and as a browsers version number is unlikely to change
   * during a session we cache the results.
   * @type {Object}
   * @private
   */
  goog.userAgent.isVersionCache_ = {};
  
  
  /**
   * Whether the user agent version is higher or the same as the given version.
   * NOTE: When checking the version numbers for Firefox and Safari, be sure to
   * use the engine's version, not the browser's version number.  For example,
   * Firefox 3.0 corresponds to Gecko 1.9 and Safari 3.0 to Webkit 522.11.
   * Opera and Internet Explorer versions match the product release number.<br>
   * @see <a href="http://en.wikipedia.org/wiki/Safari_version_history">
   *     Webkit</a>
   * @see <a href="http://en.wikipedia.org/wiki/Gecko_engine">Gecko</a>
   *
   * @param {string|number} version The version to check.
   * @return {boolean} Whether the user agent version is higher or the same as
   *     the given version.
   */
  goog.userAgent.isVersion = function(version) {
    return goog.userAgent.ASSUME_ANY_VERSION ||
        goog.userAgent.isVersionCache_[version] ||
        (goog.userAgent.isVersionCache_[version] =
            goog.string.compareVersions(goog.userAgent.VERSION, version) >= 0);
  };
  
  
  /**
   * Whether the IE effective document mode is higher or the same as the given
   * document mode version.
   * NOTE: Only for IE, return false for another browser.
   *
   * @param {number} documentMode The document mode version to check.
   * @return {boolean} Whether the IE effective document mode is higher or the
   *     same as the given version.
   */
  goog.userAgent.isDocumentMode = function(documentMode) {
    return goog.userAgent.IE && goog.userAgent.DOCUMENT_MODE >= documentMode;
  };
  
  
  /**
   * For IE version < 7, documentMode is undefined, so attempt to use the
   * CSS1Compat property to see if we are in standards mode. If we are in
   * standards mode, treat the browser version as the document mode. Otherwise,
   * IE is emulating version 5.
   * @type {number|undefined}
   * @const
   */
  goog.userAgent.DOCUMENT_MODE = (function() {
    var doc = goog.global['document'];
    if (!doc || !goog.userAgent.IE) {
      return undefined;
    }
    var mode = goog.userAgent.getDocumentMode_();
    return mode || (doc['compatMode'] == 'CSS1Compat' ?
        parseInt(goog.userAgent.VERSION, 10) : 5);
  })();
  