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 75 matching lines @@
 // net::LOAD_MAYBE_USER_GESTURE load flag. This is a fairly arbitrary
 // guess at how long to expect direct impact from a user gesture, but
 // this should be OK as the load flag is a best-effort thing only,
 // rather than being intended as fully accurate.
 const int kUserGestureWindowMs = 3500;
 
 // Ratio of |max_num_in_flight_requests_| that any one renderer is allowed to
 // use. Arbitrarily chosen.
 const double kMaxRequestsPerProcessRatio = 0.45;
 
+bool IsDetachableResourceType(const ResourceType::Type type) {
+  switch (type) {
+    case ResourceType::PREFETCH:
+      return true;
+    default:
+      return false;
+  }
+}
+
 // Aborts a request before an URLRequest has actually been created.
 void AbortRequestBeforeItStarts(ResourceMessageFilter* filter,
                                 IPC::Message* sync_result,
                                 int request_id) {
   if (sync_result) {
     SyncLoadResult result;
     result.error_code = net::ERR_ABORTED;
     ResourceHostMsg_SyncLoad::WriteReplyParams(sync_result, result);
     filter->Send(sync_result);
   } else {
@@ skipping 259 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.
-    DCHECK((*i)->GetRequestInfo()->is_download() ||
-           (*i)->GetRequestInfo()->is_stream() ||
-           (*i)->is_transferring());
+    // 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() ||
+        IsDetachableResourceType((*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
     CHECK_NE(i->second->GetRequestInfo()->GetContext(), context);
@@ skipping 261 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();
-  // 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}.
-    // TODO(rdsmith): This isn't currently true; see http://crbug.com/241176.
-    NOTREACHED();
+
+  if (!IsDetachableResourceType(info->GetResourceType())) {
+    // There should be an entry in the map created when we dispatched the
+    // request unless it's been detached.

[asanka, 2013/10/11 21:01:20]

This isn't strictly correct, is it? The entry would only be removed if the
associated renderer has died. It's not necessarily true that the entry would be
absent if the request is detachable. This check could prevent
UpdateStateForSuccessfullyStartedRequest() to be called for an entry that
exists.

[jkarlin2, 2013/10/14 14:30:00]

Done.

+    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}.
+      // TODO(rdsmith): This isn't currently true; see http://crbug.com/241176.
+      NOTREACHED();
+    }
   }
 
   int render_process_id, render_view_id;
   if (!info->GetAssociatedRenderView(&render_process_id, &render_view_id))
     return;
 
   // Notify the observers on the UI thread.
   scoped_ptr<ResourceRequestDetails> detail(new ResourceRequestDetails(
       loader->request(),
       GetCertID(loader->request(), info->GetChildID())));
@@ skipping 373 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 (IsDetachableResourceType(request_data.resource_type)) {
+    // put in detached handler

[asanka, 2013/10/11 21:01:20]

Nit: Remove comment.

[jkarlin2, 2013/10/14 14:30:00]

Done.

+    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 196 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() &&
+        !IsDetachableResourceType(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