Add a mechanism to disable IPv6....

net/base/host_resolver_impl.h

Index: net/base/host_resolver_impl.h
===================================================================
--- net/base/host_resolver_impl.h	(revision 29420)
+++ net/base/host_resolver_impl.h	(working copy)
@@ -27,7 +27,7 @@
 //            +----------- HostResolverImpl -------------+
 //            |                    |                     |
 //           Job                  Job                   Job
-//       (for host1)          (for host2)           (for hostX)
+//    (for host1, fam1)    (for host2, fam2)     (for hostx, famx)
 //       /    |   |            /   |   |             /   |   |
 //   Request ... Request  Request ... Request   Request ... Request
 //  (port1)     (port2)  (port3)      (port4)  (port5)      (portX)
@@ -70,11 +70,18 @@
   // TODO(eroman): temp hack for http://crbug.com/15513
   virtual void Shutdown();
 
+  // Prevents returning IPv6 addresses from Resolve().
+  // The default is to allow IPv6 results.
+  virtual void DisableIPv6(bool disable_ipv6) {
+    disable_ipv6_ = disable_ipv6;
+  }
+
  private:
   class Job;
   class Request;
   typedef std::vector<Request*> RequestsList;
-  typedef base::hash_map<std::string, scoped_refptr<Job> > JobMap;
+  typedef HostCache::Key Key;
+  typedef std::map<Key, scoped_refptr<Job> > JobMap;
   typedef std::vector<Observer*> ObserversList;
 
   // Returns the HostResolverProc to use for this instance.
@@ -86,8 +93,8 @@
   // Adds a job to outstanding jobs list.
   void AddOutstandingJob(Job* job);
 
-  // Returns the outstanding job for |hostname|, or NULL if there is none.
-  Job* FindOutstandingJob(const std::string& hostname);
+  // Returns the outstanding job for |key|, or NULL if there is none.
+  Job* FindOutstandingJob(const Key& key);
 
   // Removes |job| from the outstanding jobs list.
   void RemoveOutstandingJob(Job* job);
@@ -132,6 +139,9 @@
   // in the case of unit-tests which inject custom host resolving behaviors.
   scoped_refptr<HostResolverProc> resolver_proc_;
 
+  // Set to true if only IPv4 address are to be returned by Resolve().
+  bool disable_ipv6_;

[Lorenzo Colitti, 2009/10/21 23:14:08]

Instead, why not make this be "int desired_address_family" It could default to
AF_UNSPEC and then you could disable IPv6 by setting it to AF_INET.

The advantage is that you can pass this value directly into getaddrinfo(), thus
simplifying the code. Also, it's more flexible, since it allows the caller to
disable IPv6, disable IPv4, or request any address family he wants.

[eroman, 2009/10/21 23:32:07]

Done.

See proposed change here: http://codereview.chromium.org/303026

(as this codereview was already committed).

+
   // TODO(eroman): temp hack for http://crbug.com/15513
   bool shutdown_;