Validation of extension api callback and event parameters in DEBUG

chrome/renderer/resources/event_bindings.js

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // -----------------------------------------------------------------------------
 // NOTE: If you change this file you need to touch renderer_resources.grd to
 // have your change take effect.
 // -----------------------------------------------------------------------------
 
 var chrome = chrome || {};
 (function () {
   native function GetChromeHidden();
   native function AttachEvent(eventName);
   native function DetachEvent(eventName);
 
   var chromeHidden = GetChromeHidden();
 
   // Event object.  If opt_eventName is provided, this object represents
   // the unique instance of that named event, and dispatching an event
   // with that name will route through this object's listeners.
   //
   // Example:
   //   chrome.tabs.onChanged = new chrome.Event("tab-changed");
   //   chrome.tabs.onChanged.addListener(function(data) { alert(data); });
   //   chromeHidden.Event.dispatch("tab-changed", "hi");
   // will result in an alert dialog that says 'hi'.
-  chrome.Event = function(opt_eventName) {
+  chrome.Event = function(opt_eventName, opt_argSchemas) {
     this.eventName_ = opt_eventName;
     this.listeners_ = [];
+
+    // Validate event parameters if we are in debug.     
+    if (opt_argSchemas &&
+        chromeHidden.validateCallbacks &&
+        chromeHidden.validate) {
+
+      this.validate_ = function(args) {
+        try {
+          chromeHidden.validate(args, opt_argSchemas);
+        } catch (exception) {
+          return "Event validation error during " + opt_eventName + " -- " +
+                 exception;
+        }
+      }
+    }
   };
 
   // A map of event names to the event object that is registered to that name.
   var attachedNamedEvents = {};
 
   // An array of all attached event objects, used for detaching on unload.
   var allAttachedEvents = [];
 
   chromeHidden.Event = {};
 
   // Dispatches a named event with the given JSON array, which is deserialized
   // before dispatch. The JSON array is the list of arguments that will be
   // sent with the event callback.
   chromeHidden.Event.dispatchJSON = function(name, args) {
     if (attachedNamedEvents[name]) {
       if (args) {
         args = JSON.parse(args);
       }
-      attachedNamedEvents[name].dispatch.apply(
+      return attachedNamedEvents[name].dispatch.apply(
           attachedNamedEvents[name], args);
     }
   };
 
   // Dispatches a named event with the given arguments, supplied as an array.
   chromeHidden.Event.dispatch = function(name, args) {
     if (attachedNamedEvents[name]) {
       attachedNamedEvents[name].dispatch.apply(
           attachedNamedEvents[name], args);
     }
@@ skipping 40 matching lines @@
       }
     }
 
     return -1;
   };
 
   // Dispatches this event object to all listeners, passing all supplied
   // arguments to this function each listener.
   chrome.Event.prototype.dispatch = function(varargs) {
     var args = Array.prototype.slice.call(arguments);
+    if (this.validate_) {
+      var validationErrors = this.validate_(args);
+      if (validationErrors) {
+        return validationErrors;
+      }
+    }
     for (var i = 0; i < this.listeners_.length; i++) {
       try {
         this.listeners_[i].apply(null, args);
       } catch (e) {
         console.error(e);
       }
     }
   };
 
   // Attaches this event object to its name.  Only one object can have a given
@@ skipping 42 matching lines @@
   chromeHidden.dispatchOnUnload = function() {
     chromeHidden.onUnload.dispatch();
     for (var i in allAttachedEvents)
       allAttachedEvents[i].detach_();
   }
 
   chromeHidden.dispatchError = function(msg) {
     console.error(msg);
   }
 })();