extensions/renderer/resources/last_error.js

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 var GetAvailability = requireNative('v8_context').GetAvailability;
   6 var GetGlobal = requireNative('sendRequest').GetGlobal;
   7
   8 // Utility for setting chrome.*.lastError.
   9 //
  10 // A utility here is useful for two reasons:
  11 //  1. For backwards compatibility we need to set chrome.extension.lastError,
  12 //     but not all contexts actually have access to the extension namespace.
  13 //  2. When calling across contexts, the global object that gets lastError set
  14 //     needs to be that of the caller. We force callers to explicitly specify
  15 //     the chrome object to try to prevent bugs here.
  16
  17 /**
  18  * Sets the last error for |name| on |targetChrome| to |message| with an
  19  * optional |stack|.
  20  */
  21 function set(name, message, stack, targetChrome) {
  22   var errorMessage = name + ': ' + message;
  23   if (stack != null && stack != '')
  24     errorMessage += '\n' + stack;
  25
  26   if (!targetChrome)
  27     throw new Error('No chrome object to set error: ' + errorMessage);
  28   clear(targetChrome);  // in case somebody has set a sneaky getter/setter
  29
  30   var errorObject = { message: message };
  31   if (GetAvailability('extension.lastError').is_available)
  32     targetChrome.extension.lastError = errorObject;
  33
  34   assertRuntimeIsAvailable();
  35
  36   // We check to see if developers access runtime.lastError in order to decide
  37   // whether or not to log it in the (error) console.
  38   privates(targetChrome.runtime).accessedLastError = false;
  39   $Object.defineProperty(targetChrome.runtime, 'lastError', {
  40       configurable: true,
  41       get: function() {
  42         privates(targetChrome.runtime).accessedLastError = true;
  43         return errorObject;
  44       },
  45       set: function(error) {
  46         errorObject = errorObject;
  47       }});
  48 };
  49
  50 /**
  51  * Check if anyone has checked chrome.runtime.lastError since it was set.
  52  * @param {Object} targetChrome the Chrome object to check.
  53  * @return boolean True if the lastError property was set.
  54  */
  55 function hasAccessed(targetChrome) {
  56   assertRuntimeIsAvailable();
  57   return privates(targetChrome.runtime).accessedLastError === true;
  58 }
  59
  60 /**
  61  * Check whether there is an error set on |targetChrome| without setting
  62  * |accessedLastError|.
  63  * @param {Object} targetChrome the Chrome object to check.
  64  * @return boolean Whether lastError has been set.
  65  */
  66 function hasError(targetChrome) {
  67   if (!targetChrome)
  68     throw new Error('No target chrome to check');
  69
  70   assertRuntimeIsAvailable();
  71   if ('lastError' in targetChrome.runtime)
  72     return true;
  73
  74   return false;
  75 };
  76
  77 /**
  78  * Clears the last error on |targetChrome|.
  79  */
  80 function clear(targetChrome) {
  81   if (!targetChrome)
  82     throw new Error('No target chrome to clear error');
  83
  84   if (GetAvailability('extension.lastError').is_available)
  85    delete targetChrome.extension.lastError;
  86
  87   assertRuntimeIsAvailable();
  88   delete targetChrome.runtime.lastError;
  89   delete privates(targetChrome.runtime).accessedLastError;
  90 };
  91
  92 function assertRuntimeIsAvailable() {
  93   // chrome.runtime should always be available, but maybe it's disappeared for
  94   // some reason? Add debugging for http://crbug.com/258526.
  95   var runtimeAvailability = GetAvailability('runtime.lastError');
  96   if (!runtimeAvailability.is_available) {
  97     throw new Error('runtime.lastError is not available: ' +
  98                     runtimeAvailability.message);
  99   }
 100   if (!chrome.runtime)
 101     throw new Error('runtime namespace is null or undefined');
 102 }
 103
 104 /**
 105  * Runs |callback(args)| with last error args as in set().
 106  *
 107  * The target chrome object is the global object's of the callback, so this
 108  * method won't work if the real callback has been wrapped (etc).
 109  */
 110 function run(name, message, stack, callback, args) {
 111   var targetChrome = GetGlobal(callback).chrome;
 112   set(name, message, stack, targetChrome);
 113   try {
 114     $Function.apply(callback, undefined, args);
 115   } finally {
 116     clear(targetChrome);
 117   }
 118 }
 119
 120 exports.clear = clear;
 121 exports.hasAccessed = hasAccessed;
 122 exports.hasError = hasError;
 123 exports.set = set;
 124 exports.run = run;