Allows prefetch requests to live beyond the renderer by delaying

content/browser/loader/resource_loader.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.
 
 #include "content/browser/loader/resource_loader.h"
 
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/time/time.h"
+#include "base/timer/timer.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/loader/cross_site_resource_handler.h"
 #include "content/browser/loader/resource_loader_delegate.h"
 #include "content/browser/loader/resource_request_info_impl.h"
 #include "content/browser/ssl/ssl_client_auth_handler.h"
 #include "content/browser/ssl/ssl_manager.h"
 #include "content/common/ssl_status_serialization.h"
 #include "content/public/browser/cert_store.h"
 #include "content/public/browser/resource_dispatcher_host_login_delegate.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/process_type.h"
 #include "content/public/common/resource_response.h"
 #include "content/public/common/url_constants.h"
 #include "net/base/io_buffer.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_response_headers.h"
 #include "net/ssl/client_cert_store.h"
 #include "net/ssl/client_cert_store_impl.h"
 #include "webkit/browser/appcache/appcache_interceptor.h"
 
 using base::TimeDelta;
 using base::TimeTicks;
 
 namespace content {
 namespace {
 
+const int kDefaultDetachableDelayOnCancelMs = 60000;
+
 void PopulateResourceResponse(net::URLRequest* request,
                               ResourceResponse* response) {
   response->head.error_code = request->status().error();
   response->head.request_time = request->request_time();
   response->head.response_time = request->response_time();
   response->head.headers = request->response_headers();
   request->GetCharset(&response->head.charset);
   response->head.content_length = request->GetExpectedContentSize();
   request->GetMimeType(&response->head.mime_type);
   net::HttpResponseInfo response_info = request->response_info();
@@ skipping 154 matching lines @@
                           ResourceLoaderDelegate* delegate,
                           scoped_ptr<net::ClientCertStore> client_cert_store) {
   deferred_stage_ = DEFERRED_NONE;
   request_ = request.Pass();
   handler_ = handler.Pass();
   delegate_ = delegate;
   last_upload_position_ = 0;
   waiting_for_upload_progress_ack_ = false;
   is_transferring_ = false;
   client_cert_store_ = client_cert_store.Pass();
+  detachable_delay_on_cancel_ms_ = kDefaultDetachableDelayOnCancelMs;
 
   request_->set_delegate(this);
   handler_->SetController(this);
 }
 
 void ResourceLoader::OnReceivedRedirect(net::URLRequest* unused,
                                         const GURL& new_url,
                                         bool* defer) {
   DCHECK_EQ(request_.get(), unused);
 
@@ skipping 228 matching lines @@
   CancelRequest(false);
 }
 
 void ResourceLoader::StartRequestInternal() {
   DCHECK(!request_->is_pending());
   request_->Start();
 
   delegate_->DidStartRequest(this);
 }
 
+void ResourceLoader::CancelAfterTimeout() {
+  if (detached_timer_)
+    return;
+
+  detached_timer_.reset(new base::OneShotTimer<ResourceLoader>());
+  detached_timer_->Start(
+      FROM_HERE, TimeDelta::FromMilliseconds(detachable_delay_on_cancel_ms_),
+      this, &ResourceLoader::Cancel);
+}
+
 void ResourceLoader::CancelRequestInternal(int error, bool from_renderer) {
   VLOG(1) << "CancelRequestInternal: " << request_->url().spec();
 
   ResourceRequestInfoImpl* info = GetRequestInfo();
 
   // WebKit will send us a cancel for downloads since it no longer handles
   // them.  In this case, ignore the cancel since we handle downloads in the
   // browser.
   if (from_renderer && (info->is_download() || info->is_stream()))
     return;
 
+  if (from_renderer && info->is_detachable()) {
+    CancelAfterTimeout();
+    return;
+  }
+
   // TODO(darin): Perhaps we should really be looking to see if the status is
   // IO_PENDING?
   bool was_pending = request_->is_pending();
 
   if (login_delegate_.get()) {
     login_delegate_->OnRequestCancelled();
     login_delegate_ = NULL;
   }
   if (ssl_client_auth_handler_.get()) {
     ssl_client_auth_handler_->OnRequestCancelled();
@@ skipping 173 matching lines @@
     // we resume.
     deferred_stage_ = DEFERRED_FINISH;
   }
 }
 
 void ResourceLoader::CallDidFinishLoading() {
   delegate_->DidFinishLoading(this);
 }
 
 }  // namespace content