Substitute ResourceHandlers with dummy ResourceHandler while request is transferred

content/browser/renderer_host/resource_dispatcher_host.cc

 // Copyright (c) 2012 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.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #include "content/browser/renderer_host/resource_dispatcher_host.h"
 
 #include <set>
 #include <vector>
@@ skipping 14 matching lines @@
 #include "content/browser/cert_store.h"
 #include "content/browser/child_process_security_policy.h"
 #include "content/browser/chrome_blob_storage_context.h"
 #include "content/browser/cross_site_request_manager.h"
 #include "content/browser/download/download_file_manager.h"
 #include "content/browser/download/download_id_factory.h"
 #include "content/browser/download/download_resource_handler.h"
 #include "content/browser/download/save_file_manager.h"
 #include "content/browser/download/save_file_resource_handler.h"
 #include "content/browser/plugin_service_impl.h"
+#include "content/browser/renderer_host/allow_cancel_resource_handler.h"
 #include "content/browser/renderer_host/async_resource_handler.h"
 #include "content/browser/renderer_host/buffered_resource_handler.h"
 #include "content/browser/renderer_host/cross_site_resource_handler.h"
 #include "content/browser/renderer_host/redirect_to_file_resource_handler.h"
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/renderer_host/render_view_host_delegate.h"
 #include "content/browser/renderer_host/resource_dispatcher_host_login_delegate.h"
 #include "content/browser/renderer_host/resource_dispatcher_host_request_info.h"
 #include "content/browser/renderer_host/resource_message_filter.h"
 #include "content/browser/renderer_host/resource_queue.h"
@@ skipping 1251 matching lines @@
                              info->resource_handler())) {
     // The request is complete so we can remove it.
     RemovePendingRequest(info->child_id(), info->request_id());
     return;
   }
 
   scoped_refptr<ResourceResponse> response(new ResourceResponse);
   PopulateResourceResponse(request, response);
   if (!info->resource_handler()->OnRequestRedirected(info->request_id(),
                                                      new_url,
-                                                     response, defer_redirect))
+                                                     response,
+                                                     defer_redirect)) {
     CancelRequestInternal(request, false);
+    return;
+  }
+
+  // If a URLRequest is transferred to a new RenderViewHost, its
+  // ResourceHandlers should not received any notifications because they may

[Matt Perry, 2012/01/05 23:52:44]

receive*

[battre, 2012/01/06 02:18:02]

Done.

+  // depend on the state of the old RVH. We set a ResourceHandler that allows
+  // canceling requests, because on shutdown of the RDH all pending requests
+  // are canceled. The RVH of requests that are being transferred may be gone by
+  // that time.
+  GlobalRequestID global_request_id(info->child_id(), info->request_id());
+  if (IsTransferredNavigation(global_request_id))
+    info->set_resource_handler(new AllowCancelResourceHandler());

[battre, 2012/01/05 22:55:17]

We cannot put this code into the TransferNavigationResourceHandler, as resource
handlers are refcounted. We would remove the only reference to the
ResourceHandler while it is being executed.

[Matt Perry, 2012/01/05 23:52:44]

It's perfectly fine to delete an instance of a class while running one of its
methods - just as long as you don't dereference that instance after the fact.
Please move this to the TransferNavigationResourceHandler (make sure it's the
last code that gets executed before returning, and add a comment warning that it
might 'delete this').

[battre, 2012/01/06 02:18:02]

Done. Moved to MarkAsTransferredNavigation as discussed.

 }
 
 void ResourceDispatcherHost::OnAuthRequired(
     net::URLRequest* request,
     net::AuthChallengeInfo* auth_info) {
   if (request->load_flags() & net::LOAD_DO_NOT_PROMPT_FOR_LOGIN) {
     request->CancelAuth();
     return;
   }
 
@@ skipping 929 matching lines @@
     const GlobalRequestID& transferred_request_id,
     net::URLRequest* ransferred_request) {
   transferred_navigations_[transferred_request_id] = ransferred_request;
 }
 
 bool ResourceDispatcherHost::IsTransferredNavigation(
     const content::GlobalRequestID& transferred_request_id) const {
   return transferred_navigations_.find(transferred_request_id) !=
       transferred_navigations_.end();
 }