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// Copyright 2007 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 Detection for whether the user has Picasa installed.
* Only Picasa versions 2 and later can be detected, and only from Firefox or
* Internet Explorer. Picasa for Linux cannot be detected.
*
* In the future, Picasa may provide access to the installed version number,
* but until then we can only detect that Picasa 2 or later is present.
*
* To check for Picasa on Internet Explorer requires using document.write, so
* this file must be included at page rendering time and cannot be imported
* later as part of a dynamically loaded module.
*
* @author brenneman@google.com (Shawn Brenneman)
* @see ../demos/useragent.html
*/
goog.provide('goog.userAgent.picasa');
goog.require('goog.string');
goog.require('goog.userAgent');
/**
* Variable name used to temporarily save the Picasa state in the global object
* in Internet Explorer.
* @type {string}
* @private
*/
goog.userAgent.picasa.IE_HAS_PICASA_ = 'hasPicasa';
(function() {
var hasPicasa = false;
if (goog.userAgent.IE) {
// In Internet Explorer, Picasa 2 can be detected using conditional comments
// due to some nice registry magic. The precise version number is not
// available, only the major version. This may be updated for Picasa 3. This
// check must pollute the global namespace.
goog.global[goog.userAgent.picasa.IE_HAS_PICASA_] = hasPicasa;
// NOTE(user): Some browsers do not like seeing
// slash-script anywhere in the text even if it's inside a string
// and escaped with a backslash, make a string in a way that
// avoids problems.
document.write(goog.string.subs(
'<!--[if gte Picasa 2]>' +
'<%s>' +
'this.%s=true;' +
'</%s>' +
'<![endif]-->',
'script', goog.userAgent.picasa.IE_HAS_PICASA_, 'script'));
hasPicasa = goog.global[goog.userAgent.picasa.IE_HAS_PICASA_];
// Unset the variable in a crude attempt to leave no trace.
goog.global[goog.userAgent.picasa.IE_HAS_PICASA_] = undefined;
} else if (navigator.mimeTypes &&
navigator.mimeTypes['application/x-picasa-detect']) {
// Picasa 2.x registers a file handler for the MIME-type
// 'application/x-picasa-detect' for detection in Firefox. Future versions
// may make precise version detection possible.
hasPicasa = true;
}
/**
* Whether we detect the user has Picasa installed.
* @type {boolean}
*/
goog.userAgent.picasa.HAS_PICASA = hasPicasa;
/**
* The installed version of Picasa. If Picasa is detected, this means it is
* version 2 or later. The precise version number is not yet available to the
* browser, this is a placeholder for later versions of Picasa.
* @type {string}
*/
goog.userAgent.picasa.VERSION = hasPicasa ? '2' : '';
})();
/**
* Whether the installed Picasa version is as new or newer than a given version.
* This is not yet relevant, we can't detect the true Picasa version number yet,
* but this may be possible in future Picasa releases.
* @param {string} version The version to check.
* @return {boolean} Whether the installed Picasa version is as new or newer
* than a given version.
*/
goog.userAgent.picasa.isVersion = function(version) {
return goog.string.compareVersions(
goog.userAgent.picasa.VERSION, version) >= 0;
};
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