[net/dns] Serve requests from HOSTS file if possible.

net/base/host_resolver_impl.h

 // 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.
 
 #ifndef NET_BASE_HOST_RESOLVER_IMPL_H_
 #define NET_BASE_HOST_RESOLVER_IMPL_H_
 #pragma once
 
 #include <map>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/time.h"
 #include "net/base/capturing_net_log.h"
 #include "net/base/host_cache.h"
 #include "net/base/host_resolver.h"
 #include "net/base/host_resolver_proc.h"
 #include "net/base/net_export.h"
 #include "net/base/net_log.h"
 #include "net/base/network_change_notifier.h"
 #include "net/base/prioritized_dispatcher.h"
+#include "net/dns/dns_client.h"
 #include "net/dns/dns_config_service.h"
 
 namespace net {
 
-class DnsTransactionFactory;
-
 // For each hostname that is requested, HostResolver creates a
 // HostResolverImpl::Job. When this job gets dispatched it creates a ProcTask
 // which runs the given HostResolverProc on a WorkerPool thread. If requests for
 // that same host are made during the job's lifetime, they are attached to the
 // existing job rather than creating a new one. This avoids doing parallel
 // resolves for the same host.
 //
 // The way these classes fit together is illustrated by:
 //
 //
@@ skipping 104 matching lines @@
   virtual void SetDefaultAddressFamily(AddressFamily address_family) OVERRIDE;
   virtual AddressFamily GetDefaultAddressFamily() const OVERRIDE;
   virtual void ProbeIPv6Support() OVERRIDE;
   virtual HostCache* GetHostCache() OVERRIDE;
 
   // Allows the tests to catch slots leaking out of the dispatcher.
   size_t num_running_jobs_for_tests() const {
     return dispatcher_.num_running_jobs();
   }
 
+  void set_dns_client_for_tests(scoped_ptr<DnsClient> client) {

[mmenke, 2012/03/13 15:56:27]

Suggest you make this and the above function private and friend the tests.

[szym, 2012/03/13 20:06:42]

Not a fan of FRIEND_TEST*. It completely opens the guts, makes the tests pollute
the namespace, and forces the test writer to edit the class header. I'd strongly
prefer if we could friend the fixture base class (HostResolverImplTest) and put
the rest of the tests in anonymous namespace.

For now, I moved the two tests out of the anonymous namespace. I hope to address
the namespace pollution when fixing http://crbug.com/117830

[mmenke, 2012/03/13 20:31:08]

SGTM.  I prefer just friending the fixture as well.

+    dns_client_ = client.Pass();
+  }
+
  private:
   class Job;
   class ProcTask;
   class IPv6ProbeJob;
   class DnsTask;
   class Request;
   typedef HostCache::Key Key;
   typedef std::map<Key, Job*> JobMap;
   typedef std::vector<Request*> RequestsList;
 
@@ skipping 11 matching lines @@
   bool ResolveAsIP(const Key& key,
                    const RequestInfo& info,
                    int* net_error,
                    AddressList* addresses);
 
   // If |key| is not found in cache returns false, otherwise returns
   // true, sets |net_error| to the cached error code and fills |addresses|
   // if it is a positive entry.
   bool ServeFromCache(const Key& key,
                       const RequestInfo& info,
-                      const BoundNetLog& request_net_log,
                       int* net_error,
                       AddressList* addresses);
 
+  // If |key| is not found in the HOSTS file or no HOSTS file known, returns
+  // false, otherwise returns true and fills |addresses|.
+  bool ServeFromHosts(const Key& key,
+                      const RequestInfo& info,
+                      AddressList* addresses);
+
   // Notifies IPv6ProbeJob not to call back, and discard reference to the job.
   void DiscardIPv6ProbeJob();
 
   // Callback from IPv6 probe activity.
   void IPv6ProbeSetDefaultAddressFamily(AddressFamily address_family);
 
   // Returns the (hostname, address_family) key to use for |info|, choosing an
   // "effective" address family by inheriting the resolver's default address
   // family when the request leaves it unspecified.
   Key GetEffectiveKeyForRequest(const RequestInfo& info) const;
 
   // Records the result in cache if cache is present.
   void CacheResult(const Key& key,
                    int net_error,
                    const AddressList& addr_list,
                    base::TimeDelta ttl);
 
   // Removes |job| from |jobs_|, only if it exists.
   void RemoveJob(Job* job);
 
   // Aborts all in progress jobs and notifies their requests.
   // Might start new jobs.
   void AbortAllInProgressJobs();
 
+  // Attempts to serve each Job in |jobs_| from the HOSTS file.
+  void TryServingAllJobsFromHosts();
+
   // NetworkChangeNotifier::IPAddressObserver:
   virtual void OnIPAddressChanged() OVERRIDE;
 
   // NetworkChangeNotifier::DNSObserver:
   virtual void OnDNSChanged(unsigned detail) OVERRIDE;
 
   // DnsConfigService::Observer:
   virtual void OnConfigChanged(const DnsConfig& dns_config) OVERRIDE;
 
+  // True if have fully configured DNS client.
+  bool HaveDnsConfig() const;
+
   // Cache of host resolution results.
   scoped_ptr<HostCache> cache_;
 
   // Map from HostCache::Key to a Job.
   JobMap jobs_;
 
   // Starts Jobs according to their priority and the configured limits.
   PrioritizedDispatcher dispatcher_;
 
   // Limit on the maximum number of jobs queued in |dispatcher_|.
   size_t max_queued_jobs_;
 
   // Parameters for ProcTask.
   ProcTaskParams proc_params_;
 
-  scoped_ptr<DnsTransactionFactory> dns_transaction_factory_;
-
   // Address family to use when the request doesn't specify one.
   AddressFamily default_address_family_;
 
+  scoped_ptr<DnsClient> dns_client_;
   scoped_ptr<DnsConfigService> dns_config_service_;
 
   // Indicate if probing is done after each network change event to set address
   // family.
   // When false, explicit setting of address family is used.
   bool ipv6_probe_monitoring_;
 
   // The last un-cancelled IPv6ProbeJob (if any).
   scoped_refptr<IPv6ProbeJob> ipv6_probe_job_;
 
   // Any resolver flags that should be added to a request by default.
   HostResolverFlags additional_resolver_flags_;
 
   NetLog* net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(HostResolverImpl);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_HOST_RESOLVER_IMPL_H_