content::ResourceDispatcherHostImpl changes for stale-while-revalidate

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 <algorithm>
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/debug/alias.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/shared_memory.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/stl_util.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "base/time/time.h"
 #include "content/browser/appcache/appcache_interceptor.h"
 #include "content/browser/appcache/chrome_appcache_service.h"
 #include "content/browser/bad_message.h"
 #include "content/browser/cert_store_impl.h"
@@ skipping 434 matching lines @@
       &last_user_gesture_time_,
       "We don't care about the precise value, see http://crbug.com/92889");
 
   BrowserThread::PostTask(BrowserThread::IO,
                           FROM_HERE,
                           base::Bind(&ResourceDispatcherHostImpl::OnInit,
                                      base::Unretained(this)));
 
   update_load_states_timer_.reset(
       new base::RepeatingTimer<ResourceDispatcherHostImpl>());
+
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  if (base::FieldTrialList::FindFullName("StaleWhileRevalidate") == "Enabled" ||
+      command_line->HasSwitch(switches::kEnableStaleWhileRevalidate)) {
+    async_revalidation_manager_.reset(new AsyncRevalidationManager);
+  }
 }
 
 ResourceDispatcherHostImpl::~ResourceDispatcherHostImpl() {
   DCHECK(outstanding_requests_stats_map_.empty());
+  // It's not safe to destroy this object while AsyncRevalidationDriver objects
+  // have callbacks referencing it.
+  async_revalidation_manager_.reset();
   DCHECK(g_resource_dispatcher_host);
   g_resource_dispatcher_host = NULL;
 }
 
 // static
 ResourceDispatcherHostImpl* ResourceDispatcherHostImpl::Get() {
   return g_resource_dispatcher_host;
 }
 
 void ResourceDispatcherHostImpl::SetDelegate(
@@ skipping 81 matching lines @@
            (*i)->GetRequestInfo()->is_stream() ||
            ((*i)->GetRequestInfo()->detachable_handler() &&
             (*i)->GetRequestInfo()->detachable_handler()->is_detached()) ||
            (*i)->GetRequestInfo()->GetProcessType() == PROCESS_TYPE_BROWSER ||
            (*i)->is_transferring());
   }
 #endif
 
   loaders_to_cancel.clear();
 
+  if (async_revalidation_manager_) {
+    // Cancelling async revalidations should not result in the creation of new
+    // requests, but do it before the checks just to be on the safe side.
+    async_revalidation_manager_->CancelAsyncRevalidationsForResourceContext(
+        context);
+  }
+
   // 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);
   }
 
   for (BlockedLoadersMap::const_iterator i = blocked_loaders_map_.begin();
        i != blocked_loaders_map_.end(); ++i) {
     BlockedLoadersList* loaders = i->second;
@@ skipping 226 matching lines @@
 }
 
 void ResourceDispatcherHostImpl::DidReceiveRedirect(ResourceLoader* loader,
                                                     const GURL& new_url) {
   ResourceRequestInfoImpl* info = loader->GetRequestInfo();
 
   int render_process_id, render_frame_host;
   if (!info->GetAssociatedRenderFrame(&render_process_id, &render_frame_host))
     return;
 
+  // Remove the LOAD_SUPPORT_ASYNC_REVALIDATION flag if it is present.

[Bence, 2015/11/17 13:12:23]

Please explain briefly why you do this for redirects.

[Adam Rice, 2015/11/17 17:45:53]

Done.

+  net::URLRequest* request = loader->request();
+  if (request->load_flags() & net::LOAD_SUPPORT_ASYNC_REVALIDATION) {
+    int new_load_flags = request->load_flags() &
+        ~net::LOAD_SUPPORT_ASYNC_REVALIDATION;
+    request->SetLoadFlags(new_load_flags);
+  }
+
   // Notify the observers on the UI thread.
   scoped_ptr<ResourceRedirectDetails> detail(new ResourceRedirectDetails(
       loader->request(),
       GetCertID(loader->request(), info->GetChildID()),
       new_url));
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(
           &NotifyRedirectOnUI,
           render_process_id, render_frame_host, base::Passed(&detail)));
 }
 
 void ResourceDispatcherHostImpl::DidReceiveResponse(ResourceLoader* loader) {
   ResourceRequestInfoImpl* info = loader->GetRequestInfo();
   net::URLRequest* request = loader->request();
   if (request->was_fetched_via_proxy() &&
       request->was_fetched_via_spdy() &&
       request->url().SchemeIs(url::kHttpScheme)) {
     scheduler_->OnReceivedSpdyProxiedHttpResponse(
         info->GetChildID(), info->GetRouteID());
   }
 
+  if (request->response_info().async_revalidation_required && !is_shutdown_) {
+    DCHECK(async_revalidation_manager_);
+    async_revalidation_manager_->BeginAsyncRevalidation(request,
+                                                        scheduler_.get());
+  }
+
   int render_process_id, render_frame_host;
   if (!info->GetAssociatedRenderFrame(&render_process_id, &render_frame_host))
     return;
 
   // Notify the observers on the UI thread.
   scoped_ptr<ResourceRequestDetails> detail(new ResourceRequestDetails(
       request, GetCertID(request, info->GetChildID())));
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(
@@ skipping 413 matching lines @@
     // Only block image loads, as the attack applies largely to the "src"
     // property of the <img> tag. It is common for web properties to allow
     // untrusted values for <img src>; this is considered a fair thing for an
     // HTML sanitizer to do. Conversely, any HTML sanitizer that didn't
     // filter sources for <script>, <link>, <embed>, <object>, <iframe> tags
     // would be considered vulnerable in and of itself.
     do_not_prompt_for_login = true;
     load_flags |= net::LOAD_DO_NOT_USE_EMBEDDED_IDENTITY;
   }
 
+  // Check if request is eligible for async revalidation.

[Bence, 2015/11/17 13:12:23]

Optional: this comment seems to be redundant with the nicely chosen local
variable name, consider removing it.

[Adam Rice, 2015/11/17 17:45:53]

Done.

+  bool support_async_revalidation =
+      (!is_sync_load && async_revalidation_manager_ &&
+       AsyncRevalidationManager::QualifiesForAsyncRevalidation(request_data));
+
+  if (support_async_revalidation)
+    load_flags |= net::LOAD_SUPPORT_ASYNC_REVALIDATION;
+
   // Sync loads should have maximum priority and should be the only
   // requets that have the ignore limits flag set.
   if (is_sync_load) {
     DCHECK_EQ(request_data.priority, net::MAXIMUM_PRIORITY);
     DCHECK_NE(load_flags & net::LOAD_IGNORE_LIMITS, 0);
   } else {
     DCHECK_EQ(load_flags & net::LOAD_IGNORE_LIMITS, 0);
   }
   new_request->SetLoadFlags(load_flags);
 
@@ skipping 13 matching lines @@
       false,  // is download
       false,  // is stream
       allow_download,
       request_data.has_user_gesture,
       request_data.enable_load_timing,
       request_data.enable_upload_progress,
       do_not_prompt_for_login,
       request_data.referrer_policy,
       request_data.visiblity_state,
       resource_context, filter_->GetWeakPtr(),
-      !is_sync_load);
+      !is_sync_load,
+      support_async_revalidation ? request_data.headers : std::string());
   // Request takes ownership.
   extra_info->AssociateWithRequest(new_request.get());
 
   if (new_request->url().SchemeIs(url::kBlobScheme)) {
     // Hang on to a reference to ensure the blob is not released prior
     // to the job being started.
     storage::BlobProtocolHandler::SetRequestedBlobDataHandle(
         new_request.get(),
         filter_->blob_storage_context()->context()->GetBlobDataFromPublicURL(
             new_request->url()));
@@ skipping 250 matching lines @@
       false,     // is_stream
       download,  // allow_download
       false,     // has_user_gesture
       false,     // enable_load_timing
       false,     // enable_upload_progress
       false,     // do_not_prompt_for_login
       blink::WebReferrerPolicyDefault,
       blink::WebPageVisibilityStateVisible,
       context,
       base::WeakPtr<ResourceMessageFilter>(),  // filter
-      true);                                   // is_async
+      true,                                    // is_async
+      std::string());                          // original_headers
 }
 
 void ResourceDispatcherHostImpl::OnRenderViewHostCreated(int child_id,
                                                          int route_id,
                                                          bool is_visible,
                                                          bool is_audible) {
   scheduler_->OnClientCreated(child_id, route_id, is_visible, is_audible);
 }
 
 void ResourceDispatcherHostImpl::OnRenderViewHostDeleted(
@@ skipping 422 matching lines @@
       true,   // enable_load_timing
       false,  // enable_upload_progress
       false,  // do_not_prompt_for_login
       info.common_params.referrer.policy,
       // TODO(davidben): This is only used for prerenders. Replace
       // is_showing with something for that. Or maybe it just comes from the
       // same mechanism as the cookie one.
       blink::WebPageVisibilityStateVisible,
       resource_context,
       base::WeakPtr<ResourceMessageFilter>(),  // filter
-      true);
+      true,                                    // is_async
+      std::string());                          // original_headers
   // Request takes ownership.
   extra_info->AssociateWithRequest(new_request.get());
 
   if (new_request->url().SchemeIs(url::kBlobScheme)) {
     // Hang on to a reference to ensure the blob is not released prior
     // to the job being started.
     ChromeBlobStorageContext* blob_context =
         GetChromeBlobStorageContextForResourceContext(resource_context);
     storage::BlobProtocolHandler::SetRequestedBlobDataHandle(
         new_request.get(),
@@ skipping 13 matching lines @@
   handler = AddStandardHandlers(new_request.get(), resource_type,
                                 resource_context,
                                 nullptr,  // appcache_service
                                 -1,  // child_id
                                 -1,  // route_id
                                 handler.Pass());
 
   BeginRequestInternal(new_request.Pass(), handler.Pass());
 }
 
+void ResourceDispatcherHostImpl::EnableStaleWhileRevalidateForTesting() {
+  // Do nothing if it is enabled already.
+  if (!async_revalidation_manager_)
+    async_revalidation_manager_.reset(new AsyncRevalidationManager);
+}
+
 // static
 int ResourceDispatcherHostImpl::CalculateApproximateMemoryCost(
     net::URLRequest* request) {
   // The following fields should be a minor size contribution (experimentally
   // on the order of 100). However since they are variable length, it could
   // in theory be a sizeable contribution.
   int strings_cost = request->extra_request_headers().ToString().size() +
                      request->original_url().spec().size() +
                      request->referrer().size() +
                      request->method().size();
@@ skipping 313 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