ui/file_manager/video_player/js/error_util.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 /**
   6  * This variable is checked in SelectFileDialogExtensionBrowserTest.
   7  * @type {number}
   8  */
   9 window.JSErrorCount = 0;
  10
  11 /**
  12  * Counts uncaught exceptions.
  13  */
  14 window.onerror = function() { window.JSErrorCount++; };
  15
  16 /**
  17  * Wraps the function to use it as a callback.
  18  * This does:
  19  *  - Capture the stack trace in case of error.
  20  *  - Bind this object
  21  *
  22  * @param {Object=} opt_thisObject Object to be used as this.
  23  * @param {...} var_args Arguments to be bound with the wrapped function.
  24  * @return {function(...)} Wrapped function.
  25  */
  26 Function.prototype.wrap = function(opt_thisObject, var_args) {
  27   var func = this;
  28   var liveStack = (new Error('Stack trace before async call')).stack;
  29   var thisObject = opt_thisObject || null;
  30   var boundArguments = Array.prototype.slice.call(arguments, 1);
  31
  32   return function wrappedCallback(var_args) {
  33     try {
  34       var args = boundArguments.concat(Array.prototype.slice.call(arguments));
  35       return func.apply(thisObject, args);
  36     } catch (e) {
  37       // Some async function doesn't handle exception correctly. So outputting
  38       // the exception message and stack trace just in case.
  39       // The message will show twice if the caller handles exception correctly.
  40       console.error(e.stack);
  41       console.info('Exception above happened in callback.', liveStack);
  42
  43       window.JSErrorCount++;
  44       throw e;
  45     }
  46   }
  47 };