Download resumption - Preliminary

content/browser/renderer_host/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/renderer_host/resource_dispatcher_host_impl.h"
 
 #include <set>
 #include <vector>
@@ skipping 31 matching lines @@
 #include "content/browser/renderer_host/throttling_resource_handler.h"
 #include "content/browser/renderer_host/transfer_navigation_resource_throttle.h"
 #include "content/browser/resource_context_impl.h"
 #include "content/browser/worker_host/worker_service_impl.h"
 #include "content/common/resource_messages.h"
 #include "content/common/ssl_status_serialization.h"
 #include "content/common/view_messages.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/download_manager.h"
+#include "content/public/browser/download_save_info.h"
 #include "content/public/browser/global_request_id.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/resource_dispatcher_host_delegate.h"
 #include "content/public/browser/resource_request_details.h"
 #include "content/public/browser/resource_throttle.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/process_type.h"
 #include "content/public/common/url_constants.h"
 #include "net/base/auth.h"
@@ skipping 429 matching lines @@
 }
 
 net::Error ResourceDispatcherHostImpl::BeginDownload(
     scoped_ptr<net::URLRequest> request,
     bool is_content_initiated,
     ResourceContext* context,
     int child_id,
     int route_id,
     bool prefer_cache,
     scoped_ptr<DownloadSaveInfo> save_info,
+    const std::string& last_modified,
+    const std::string& etag,
+    content::DownloadId download_id,
     const DownloadStartedCallback& started_callback) {
   if (is_shutdown_)
     return CallbackAndReturn(started_callback, net::ERR_INSUFFICIENT_RESOURCES);
 
   const GURL& url = request->original_url();
 
   // http://crbug.com/90971
   char url_buf[128];
   base::strlcpy(url_buf, url.spec().c_str(), arraysize(url_buf));
   base::debug::Alias(url_buf);
@@ skipping 18 matching lines @@
   if (!ChildProcessSecurityPolicyImpl::GetInstance()->
           CanRequestURL(child_id, url)) {
     VLOG(1) << "Denied unauthorized download request for "
             << url.possibly_invalid_spec();
     return CallbackAndReturn(started_callback, net::ERR_ACCESS_DENIED);
   }
 
   request_id_--;
 
   const net::URLRequestContext* request_context = context->GetRequestContext();
+
+  // If we're not at the beginning of the file, retrieve only the remaining
+  // portion.
+  if (save_info->offset > 0) {
+    request->SetExtraRequestHeaderByName(
+        "Range",
+        StringPrintf("bytes=%" PRId64 "-", save_info->offset),
+        true);
+  }
+
+  // If it's the second (or later) request for this file, make sure it
+  // hasn't been modified.
+  if (!last_modified.empty()) {
+    request->SetExtraRequestHeaderByName("If-Unmodified-Since",
+                                         last_modified,
+                                         true);
+  }
+  if (!etag.empty()) {
+    // Set requested ETAG.
+    request->SetExtraRequestHeaderByName("If-Match", etag, true);
+  }
   if (!request_context->job_factory()->IsHandledURL(url)) {
     VLOG(1) << "Download request for unsupported protocol: "
             << url.possibly_invalid_spec();
     return CallbackAndReturn(started_callback, net::ERR_ACCESS_DENIED);
   }
 
   ResourceRequestInfoImpl* extra_info =
       CreateRequestInfo(child_id, route_id, true, context);
   extra_info->AssociateWithRequest(request.get());  // Request takes ownership.
 
@@ skipping 1171 matching lines @@
 
   return i->second.get();
 }
 
 ResourceLoader* ResourceDispatcherHostImpl::GetLoader(int child_id,
                                                       int request_id) const {
   return GetLoader(GlobalRequestID(child_id, request_id));
 }
 
 }  // namespace content