gears_init.js

   1 // Copyright 2007, Google Inc.
   2 //
   3 // Redistribution and use in source and binary forms, with or without
   4 // modification, are permitted provided that the following conditions are met:
   5 //
   6 //  1. Redistributions of source code must retain the above copyright notice,
   7 //     this list of conditions and the following disclaimer.
   8 //  2. Redistributions in binary form must reproduce the above copyright notice,
   9 //     this list of conditions and the following disclaimer in the documentation
  10 //     and/or other materials provided with the distribution.
  11 //  3. Neither the name of Google Inc. nor the names of its contributors may be
  12 //     used to endorse or promote products derived from this software without
  13 //     specific prior written permission.
  14 //
  15 // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  16 // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  17 // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
  18 // EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  19 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  20 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  21 // OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  22 // WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  23 // OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  24 // ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25 //
  26 // Sets up google.gears.*, which is *the only* supported way to access Gears.
  27 //
  28 // Circumvent this file at your own risk!
  29 //
  30 // In the future, Gears may automatically define google.gears.* without this
  31 // file. Gears may use these objects to transparently fix bugs and compatibility
  32 // issues. Applications that use the code below will continue to work seamlessly
  33 // when that happens.
  34
  35 (function() {
  36   // We are already defined. Hooray!
  37   if (window.google && google.gears) {
  38     return;
  39   }
  40
  41   var factory = null;
  42
  43   // Firefox
  44   if (typeof GearsFactory != 'undefined') {
  45     factory = new GearsFactory();
  46   } else {
  47     // IE
  48     try {
  49       factory = new ActiveXObject('Gears.Factory');
  50       // privateSetGlobalObject is only required and supported on IE Mobile on
  51       // WinCE.
  52       if (factory.getBuildInfo().indexOf('ie_mobile') != -1) {
  53         factory.privateSetGlobalObject(this);
  54       }
  55     } catch (e) {
  56       // Safari
  57       if ((typeof navigator.mimeTypes != 'undefined')
  58            && navigator.mimeTypes["application/x-googlegears"]) {
  59         factory = document.createElement("object");
  60         factory.style.display = "none";
  61         factory.width = 0;
  62         factory.height = 0;
  63         factory.type = "application/x-googlegears";
  64         document.documentElement.appendChild(factory);
  65       }
  66     }
  67   }
  68
  69   // *Do not* define any objects if Gears is not installed. This mimics the
  70   // behavior of Gears defining the objects in the future.
  71   if (!factory) {
  72     return;
  73   }
  74
  75   // Now set up the objects, being careful not to overwrite anything.
  76   //
  77   // Note: In Internet Explorer for Windows Mobile, you can't add properties to
  78   // the window object. However, global objects are automatically added as
  79   // properties of the window object in all browsers.
  80   if (!window.google) {
  81     google = {};
  82   }
  83
  84   if (!google.gears) {
  85     google.gears = {factory: factory};
  86   }
  87 })();