Introduce ERR_NETWORK_CHANGED and allow URLFetcher to automatically retry on that error.

net/base/host_resolver_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.
 
 #include "net/base/host_resolver_impl.h"
 
 #if defined(OS_WIN)
 #include <Winsock2.h>
 #elif defined(OS_POSIX)
 #include <netdb.h>
@@ skipping 1251 matching lines @@
     } else {
       // If we were called from a Request's callback within CompleteRequests,
       // that Request could not have been cancelled, so num_active_requests()
       // could not be 0. Therefore, we are not in CompleteRequests().
       CompleteRequestsWithError(OK /* cancelled */);
     }
   }
 
   // Called from AbortAllInProgressJobs. Completes all requests as aborted
   // and destroys the job.
-  void Abort() {
+  void Abort(int error) {
     DCHECK(is_running());
-    CompleteRequestsWithError(ERR_ABORTED);
+    CompleteRequestsWithError(error);

[szym, 2012/12/10 18:36:31]

The only changes needed in host_resolver_impl.{h,cc} are to
(1) change ERR_ABORTED to ERR_NETWORK_CHANGED here.

[Joao da Silva, 2012/12/11 13:36:43]

Done.

   }
 
   // If DnsTask present, abort it and fall back to ProcTask.
   void AbortDnsTask() {
     if (dns_task_) {
       dns_task_.reset();
       dns_task_error_ = OK;
       StartProcTask();
     }
   }
@@ skipping 240 matching lines @@
     DCHECK(!requests_.empty());
 
     if (entry.error == OK) {
       // Record this histogram here, when we know the system has a valid DNS
       // configuration.
       UMA_HISTOGRAM_BOOLEAN("AsyncDNS.HaveDnsConfig",
                             resolver_->received_dns_config_);
     }
 
     bool did_complete = (entry.error != ERR_ABORTED) &&
+                        (entry.error != ERR_NETWORK_CHANGED) &&

[szym, 2012/12/10 18:36:31]

(2) change ERR_ABORTED to ERR_NETWORK_CHANGED here.

[Joao da Silva, 2012/12/11 13:36:43]

Done.

                         (entry.error != ERR_HOST_RESOLVER_QUEUE_TOO_LARGE);
     if (did_complete)
       resolver_->CacheResult(key_, entry, ttl);
 
     // Complete all of the requests that were attached to the job.
     for (RequestsList::const_iterator it = requests_.begin();
          it != requests_.end(); ++it) {
       Request* req = *it;
 
       if (req->was_canceled())
@@ skipping 480 matching lines @@
   AddressFamily effective_address_family = info.address_family();
   if (effective_address_family == ADDRESS_FAMILY_UNSPECIFIED &&
       default_address_family_ != ADDRESS_FAMILY_UNSPECIFIED) {
     effective_address_family = default_address_family_;
     if (ipv6_probe_monitoring_)
       effective_flags |= HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
   }
   return Key(info.hostname(), effective_address_family, effective_flags);
 }
 
-void HostResolverImpl::AbortAllInProgressJobs() {
+void HostResolverImpl::AbortAllInProgressJobs(int error) {
   // In Abort, a Request callback could spawn new Jobs with matching keys, so
   // first collect and remove all running jobs from |jobs_|.
   ScopedVector<Job> jobs_to_abort;
   for (JobMap::iterator it = jobs_.begin(); it != jobs_.end(); ) {
     Job* job = it->second;
     if (job->is_running()) {
       jobs_to_abort.push_back(job);
       jobs_.erase(it++);
     } else {
       DCHECK(job->is_queued());
       ++it;
     }
   }
 
   // Check if no dispatcher slots leaked out.
   DCHECK_EQ(dispatcher_.num_running_jobs(), jobs_to_abort.size());
 
   // Life check to bail once |this| is deleted.
   base::WeakPtr<HostResolverImpl> self = weak_ptr_factory_.GetWeakPtr();
 
   // Then Abort them.
   for (size_t i = 0; self && i < jobs_to_abort.size(); ++i) {
-    jobs_to_abort[i]->Abort();
+    jobs_to_abort[i]->Abort(error);
     jobs_to_abort[i] = NULL;
   }
 }
 
 void HostResolverImpl::TryServingAllJobsFromHosts() {
   if (!HaveDnsConfig())
     return;
 
   // TODO(szym): Do not do this if nsswitch.conf instructs not to.
   // http://crbug.com/117655
@@ skipping 12 matching lines @@
 void HostResolverImpl::OnIPAddressChanged() {
   // Abandon all ProbeJobs.
   probe_weak_ptr_factory_.InvalidateWeakPtrs();
   if (cache_.get())
     cache_->clear();
   if (ipv6_probe_monitoring_)
     new IPv6ProbeJob(probe_weak_ptr_factory_.GetWeakPtr(), net_log_);
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
   new LoopbackProbeJob(probe_weak_ptr_factory_.GetWeakPtr());
 #endif
-  AbortAllInProgressJobs();
+  AbortAllInProgressJobs(ERR_NETWORK_CHANGED);
   // |this| may be deleted inside AbortAllInProgressJobs().
 }
 
 void HostResolverImpl::OnDNSChanged() {
   DnsConfig dns_config;
   NetworkChangeNotifier::GetDnsConfig(&dns_config);
   if (net_log_) {
     net_log_->AddGlobalEntry(
         NetLog::TYPE_DNS_CONFIG_CHANGED,
         base::Bind(&NetLogDnsConfigCallback, &dns_config));
@@ skipping 17 matching lines @@
   // as NSCD's cache should be dropped automatically by the OS when
   // resolv.conf changes so we don't need to do anything to clear that cache.
   if (cache_.get())
     cache_->clear();
 
   // Life check to bail once |this| is deleted.
   base::WeakPtr<HostResolverImpl> self = weak_ptr_factory_.GetWeakPtr();
 
   // Existing jobs will have been sent to the original server so they need to
   // be aborted.
-  AbortAllInProgressJobs();
+  AbortAllInProgressJobs(ERR_NETWORK_CHANGED);
 
   // |this| may be deleted inside AbortAllInProgressJobs().
   if (self)
     TryServingAllJobsFromHosts();
 }
 
 bool HostResolverImpl::HaveDnsConfig() const {
   return (dns_client_.get() != NULL) && (dns_client_->GetConfig() != NULL);
 }
 
@@ skipping 25 matching lines @@
   }
   DnsConfig dns_config;
   NetworkChangeNotifier::GetDnsConfig(&dns_config);
   dns_client_->SetConfig(dns_config);
   num_dns_failures_ = 0;
   if (dns_config.IsValid())
     UMA_HISTOGRAM_BOOLEAN("AsyncDNS.DnsClientEnabled", true);
 }
 
 }  // namespace net