Allows prefetch requests to live beyond the renderer by delaying

content/browser/loader/resource_dispatcher_host_impl.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/loader/resource_dispatcher_host_impl.h"
 
 #include <set>
 #include <vector>
@@ skipping 14 matching lines @@
 #include "content/browser/appcache/chrome_appcache_service.h"
 #include "content/browser/cert_store_impl.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/cross_site_request_manager.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/fileapi/chrome_blob_storage_context.h"
 #include "content/browser/loader/async_resource_handler.h"
 #include "content/browser/loader/buffered_resource_handler.h"
+#include "content/browser/loader/detached_resource_handler.h"
 #include "content/browser/loader/cross_site_resource_handler.h"
 #include "content/browser/loader/power_save_block_resource_throttle.h"
 #include "content/browser/loader/redirect_to_file_resource_handler.h"
 #include "content/browser/loader/resource_message_filter.h"
 #include "content/browser/loader/resource_request_info_impl.h"
 #include "content/browser/loader/stream_resource_handler.h"
 #include "content/browser/loader/sync_resource_handler.h"
 #include "content/browser/loader/throttling_resource_handler.h"
 #include "content/browser/loader/upload_data_stream_builder.h"
 #include "content/browser/plugin_service_impl.h"
@@ skipping 354 matching lines @@
       delete loaders;
     } else {
       ++i;
     }
   }
 
 #ifndef NDEBUG
   for (LoaderList::iterator i = loaders_to_cancel.begin();
        i != loaders_to_cancel.end(); ++i) {
     // There is no strict requirement that this be the case, but currently
-    // downloads, streams  and transferred requests are the only requests that
-    // aren't cancelled when the associated processes go away. It may be OK for
-    // this invariant to change in the future, but if this assertion fires
-    // without the invariant changing, then it's indicative of a leak.
+    // downloads, streams, prefetches, and transferred requests are the only
+    // requests that aren't cancelled when the associated processes go away. It
+    // may be OK for this invariant to change in the future, but if this
+    // assertion fires without the invariant changing, then it's indicative of a
+    // leak.
     DCHECK((*i)->GetRequestInfo()->is_download() ||
            (*i)->GetRequestInfo()->is_stream() ||
+           DetachableType((*i)->GetRequestInfo()->GetResourceType()) ||
            (*i)->is_transferring());
   }
 #endif
 
   loaders_to_cancel.clear();
 
   // Validate that no more requests for this context were added.
   for (LoaderMap::const_iterator i = pending_loaders_.begin();
        i != pending_loaders_.end(); ++i) {
     // http://crbug.com/90971
@@ skipping 262 matching lines @@
       new_url));
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(
           &NotifyRedirectOnUI,
           render_process_id, render_view_id, base::Passed(&detail)));
 }
 
 void ResourceDispatcherHostImpl::DidReceiveResponse(ResourceLoader* loader) {
   ResourceRequestInfoImpl* info = loader->GetRequestInfo();
+
+  // Exit early in case of detachable types as they may not have a policy after
+  // the renderer is canceled.
+  if (DetachableType(info->GetResourceType()))
+    return;

[mmenke, 2013/10/11 16:39:07]

Should this only protect against messing with the offline_policy_map?  Seems
like passing in the ResourceRequestDetails may be important/relevant, though I'm
not sure what it actually does.

[jkarlin2, 2013/10/11 18:37:04]

Done.

+
   // There should be an entry in the map created when we dispatched the
   // request.
   OfflineMap::iterator policy_it(
       offline_policy_map_.find(info->GetGlobalRoutingID()));
   if (offline_policy_map_.end() != policy_it) {
     policy_it->second->UpdateStateForSuccessfullyStartedRequest(
         loader->request()->response_info());
   } else {
     // We should always have an entry in offline_policy_map_ from when
     // this request traversed Begin{Download,SaveFile,Request}.
@@ skipping 385 matching lines @@
 
   // Have the appcache associate its extra info with the request.
   appcache::AppCacheInterceptor::SetExtraRequestInfo(
       request, filter_->appcache_service(), child_id,
       request_data.appcache_host_id, request_data.resource_type);
 
   // Construct the IPC resource handler.
   scoped_ptr<ResourceHandler> handler;
   if (sync_result) {
     handler.reset(new SyncResourceHandler(request, sync_result, this));
+  } else if (DetachableType(request_data.resource_type)) {
+    // put in detached handler
+    handler.reset(new DetachedResourceHandler(request, this));
   } else {
     handler.reset(new AsyncResourceHandler(request, this));
   }
 
   // The RedirectToFileResourceHandler depends on being next in the chain.
   if (request_data.download_to_file) {
     handler.reset(
         new RedirectToFileResourceHandler(handler.Pass(), request, this));
   }
 
@@ skipping 27 matching lines @@
 
   throttles.push_back(
       scheduler_->ScheduleRequest(child_id, route_id, request).release());
 
   handler.reset(
       new ThrottlingResourceHandler(handler.Pass(), request, throttles.Pass()));
 
   BeginRequestInternal(new_request.Pass(), handler.Pass());
 }
 
+bool ResourceDispatcherHostImpl::DetachableType(

[mmenke, 2013/10/11 16:39:07]

Suggest IsDetachableResouceType, or maybe IsResouceTypeDetachable.

[mmenke, 2013/10/11 16:39:07]

Since this is only used in this file and doesn't depend on |this|, suggest
moving it into a private namespace.

[jkarlin2, 2013/10/11 18:37:04]

Done.

[jkarlin2, 2013/10/11 18:37:04]

Done.

+    const ResourceType::Type type) const {
+  switch (type) {
+    case ResourceType::PREFETCH:
+      return true;
+    default:
+      return false;
+  }
+}
+
 void ResourceDispatcherHostImpl::OnReleaseDownloadedFile(int request_id) {
   UnregisterDownloadedTempFile(filter_->child_id(), request_id);
 }
 
 void ResourceDispatcherHostImpl::OnDataDownloadedACK(int request_id) {
   // TODO(michaeln): maybe throttle DataDownloaded messages
 }
 
 void ResourceDispatcherHostImpl::RegisterDownloadedTempFile(
     int child_id, int request_id, ShareableFileReference* reference) {
@@ skipping 149 matching lines @@
   ResourceLoader* loader = GetLoader(id);
   if (loader) {
     // The response we were meant to resume could have already been canceled.
     ResourceRequestInfoImpl* info = loader->GetRequestInfo();
     if (info->cross_site_handler())
       info->cross_site_handler()->ResumeResponse();
   }
 }
 
 // The object died, so cancel and detach all requests associated with it except
-// for downloads, which belong to the browser process even if initiated via a
-// renderer.
+// for downloads and prefetches, which belong to the browser process even if
+// initiated via a renderer.
 void ResourceDispatcherHostImpl::CancelRequestsForProcess(int child_id) {
   CancelRequestsForRoute(child_id, -1 /* cancel all */);
   registered_temp_files_.erase(child_id);
 }
 
 void ResourceDispatcherHostImpl::CancelRequestsForRoute(int child_id,
                                                         int route_id) {
   // Since pending_requests_ is a map, we first build up a list of all of the
   // matching requests to be cancelled, and then we cancel them.  Since there
   // may be more than one request to cancel, we cannot simply hold onto the map
   // iterators found in the first loop.
 
   // Find the global ID of all matching elements.
   bool any_requests_transferring = false;
   std::vector<GlobalRequestID> matching_requests;
   for (LoaderMap::const_iterator i = pending_loaders_.begin();
        i != pending_loaders_.end(); ++i) {
     if (i->first.child_id != child_id)
       continue;
 
     ResourceRequestInfoImpl* info = i->second->GetRequestInfo();
 
     GlobalRequestID id(child_id, i->first.request_id);
     DCHECK(id == i->first);
-
-    // Don't cancel navigations that are transferring to another process,
-    // since they belong to another process now.
+    // Don't cancel navigations that are expected to live beyond this process.
     if (IsTransferredNavigation(id))
       any_requests_transferring = true;
     if (!info->is_download() && !info->is_stream() &&
+        !DetachableType(info->GetResourceType()) &&
         !IsTransferredNavigation(id) &&
         (route_id == -1 || route_id == info->GetRouteID())) {
       matching_requests.push_back(id);
     }
   }
 
   // Remove matches.
   for (size_t i = 0; i < matching_requests.size(); ++i) {
     LoaderMap::iterator iter = pending_loaders_.find(matching_requests[i]);
     // Although every matching request was in pending_requests_ when we built
@@ skipping 552 matching lines @@
   if ((load_flags & net::LOAD_REPORT_RAW_HEADERS)
       && !policy->CanReadRawCookies(child_id)) {
     VLOG(1) << "Denied unauthorized request for raw headers";
     load_flags &= ~net::LOAD_REPORT_RAW_HEADERS;
   }
 
   return load_flags;
 }
 
 }  // namespace content