Implement offline mode behind a flag

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 213 matching lines @@
     net::Error net_error) {
   if (started_cb.is_null())
     return net_error;
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(started_cb, static_cast<DownloadItem*>(NULL), net_error));
 
   return net_error;
 }
 
-int BuildLoadFlagsForRequest(const ResourceHostMsg_Request& request_data,
-                             int child_id, bool is_sync_load) {
+int BuildLoadFlagsForRequest(
+    const ResourceHostMsg_Request& request_data, int child_id,

[darin (slow to review), 2013/04/11 20:01:23]

nit: I think the style guide says to put one argument per line when the
arguments start on the line following the function name.

[Randy Smith (Not in Mondays), 2013/04/12 14:06:44]

Wow, right you are.  I wonder if that changed recently--I remembered decls as
being strict and defns as being more freeform (as in the original for this
function).  Done.

+    bool is_sync_load) {
   int load_flags = request_data.load_flags;
 
   // Although EV status is irrelevant to sub-frames and sub-resources, we have
   // to perform EV certificate verification on all resources because an HTTP
   // keep-alive connection created to load a sub-frame or a sub-resource could
   // be reused to load a main frame.
   load_flags |= net::LOAD_VERIFY_EV_CERT;
   if (request_data.resource_type == ResourceType::MAIN_FRAME) {
     load_flags |= net::LOAD_MAIN_FRAME;
   } else if (request_data.resource_type == ResourceType::SUB_FRAME) {
@@ skipping 449 matching lines @@
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(
           &NotifyOnUI<ResourceRedirectDetails>,
           static_cast<int>(NOTIFICATION_RESOURCE_RECEIVED_REDIRECT),
           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

[darin (slow to review), 2013/04/11 20:01:23]

DCHECK that this is true?  operator[] will create an entry if one doesn't
already exist.

[Randy Smith (Not in Mondays), 2013/04/12 14:06:44]

So my basic response to this is "Sure" and I'll put it in.  However, I'll also
call out the reason I didn't originally put it in, which is that I've seen
guidance on chromium-dev (pkasting@ comes to mind) that if you're going to
dereference a variable, you shouldn't add in the extra DCHECK, and if the
reference creates an entry when it's not there, I believe it'll be NULL, and
that'll result in a crash on the line below.

Done.

+  // request.
+  offline_map_[ProcessRouteIDs(info->GetChildID(), info->GetRouteID())]->

[darin (slow to review), 2013/04/11 20:01:23]

It could also be reasonable for ResourceRequestInfoImpl to have a
GetGlobalRoutingID function.  Hmm, that might be useful elsewhere.

[Randy Smith (Not in Mondays), 2013/04/12 14:06:44]

Done, though it was a bit of a yak shave.  If you have anything more than nits
about this implementation, I'd like to pull it out into a separate CL, just so
that discussion around it doesn't delay this CL.  

One note:  The replacement of "struct GlobalRequestID;" with the inclusion of
the file it was in was the belief that if GlobalRequestID was being used as a
key in maps in rdhi.h the actual structure needed to be known by rdhi.h,
semi-confirmed by successfully compiling with the "struct GlobalRequestID;"
removed, followed by putting the include in for IWYU.  If you object to any of
that I can reverse it, but it made sense at the time :-}.

+      RequestCompleted(loader->request()->response_info());
 
   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())));
   BrowserThread::PostTask(
@@ skipping 214 matching lines @@
                                                   resource_context,
                                                   referrer)) {
     AbortRequestBeforeItStarts(filter_, sync_result, route_id, request_id);
     return;
   }
 
   bool is_sync_load = sync_result != NULL;
   int load_flags =
       BuildLoadFlagsForRequest(request_data, child_id, is_sync_load);
 
+  ProcessRouteIDs id(child_id, route_id);
+  if (!offline_map_[id])
+    offline_map_[id] = new OfflinePolicy();
+  load_flags |= offline_map_[id]->GetAdditionalLoadFlags(
+      load_flags, request_data.resource_type);
+
   // Construct the request.
   scoped_ptr<net::URLRequest> new_request;
   net::URLRequest* request;
   if (deferred_loader.get()) {
     request = deferred_loader->request();
 
     // Give the ResourceLoader (or any of the ResourceHandlers held by it) a
     // chance to reset some state before we complete the transfer.
     deferred_loader->WillCompleteTransfer();
   } else {
@@ skipping 415 matching lines @@
     for (BlockedLoadersMap::const_iterator iter = blocked_loaders_map_.begin();
          iter != blocked_loaders_map_.end(); ++iter) {
       if (iter->first.first == child_id)
         route_ids.insert(iter->first.second);
     }
     for (std::set<int>::const_iterator iter = route_ids.begin();
         iter != route_ids.end(); ++iter) {
       CancelBlockedRequestsForRoute(child_id, *iter);
     }
   }
+
+  // Cleanup the offline state for the route.
+  delete offline_map_[ProcessRouteIDs(child_id, route_id)];
+  offline_map_.erase(ProcessRouteIDs(child_id, route_id));
 }
 
 // Cancels the request and removes it from the list.
 void ResourceDispatcherHostImpl::RemovePendingRequest(int child_id,
                                                       int request_id) {
   LoaderMap::iterator i = pending_loaders_.find(
       GlobalRequestID(child_id, request_id));
   if (i == pending_loaders_.end()) {
     NOTREACHED() << "Trying to remove a request that's not here";
     return;
@@ skipping 372 matching lines @@
   DelegateMap::iterator it = delegate_map_.find(id);
   DCHECK(it->second->HasObserver(delegate));
   it->second->RemoveObserver(delegate);
   if (it->second->size() == 0) {
     delete it->second;
     delegate_map_.erase(it);
   }
 }
 
 }  // namespace content