Add a mechanism to disable IPv6....

net/base/host_cache.h

 // Copyright (c) 2009 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_CACHE_H_
 #define NET_BASE_HOST_CACHE_H_
 
+#include <map>
 #include <string>
 
-#include "base/hash_tables.h"
 #include "base/ref_counted.h"
 #include "base/time.h"
+#include "net/base/address_family.h"
 #include "net/base/address_list.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 
 namespace net {
 
 // Cache used by HostResolver to map hostnames to their resolved result.
 class HostCache {
  public:
   // Stores the latest address list that was looked up for a hostname.
   struct Entry : public base::RefCounted<Entry> {
     Entry(int error, const AddressList& addrlist, base::TimeTicks expiration);
     ~Entry();
 
     // The resolve results for this entry.
     int error;
     AddressList addrlist;
 
     // The time when this entry expires.
     base::TimeTicks expiration;
   };
 
-  typedef base::hash_map<std::string, scoped_refptr<Entry> > EntryMap;
+  struct Key {
+    Key(const std::string& hostname, AddressFamily address_family)
+        : hostname(hostname), address_family(address_family) {}
+
+    bool operator==(const Key& other) const {
+      return other.hostname == hostname &&
+             other.address_family == address_family;
+    }
+
+    bool operator<(const Key& other) const {
+      if (address_family < other.address_family)
+        return true;
+      return hostname < other.hostname;
+    }
+
+    std::string hostname;
+    AddressFamily address_family;
+  };
+
+  typedef std::map<Key, scoped_refptr<Entry> > EntryMap;
 
   // Constructs a HostCache whose entries are valid for |cache_duration_ms|
   // milliseconds. The cache will store up to |max_entries|.
   HostCache(size_t max_entries, size_t cache_duration_ms);
 
   ~HostCache();
 
-  // Returns a pointer to the entry for |hostname|, which is valid at time
+  // Returns a pointer to the entry for |key|, which is valid at time
   // |now|. If there is no such entry, returns NULL.
-  const Entry* Lookup(const std::string& hostname, base::TimeTicks now) const;
+  const Entry* Lookup(const Key& key, base::TimeTicks now) const;
 
-  // Overwrites or creates an entry for |hostname|. Returns the pointer to the
+  // Overwrites or creates an entry for |key|. Returns the pointer to the
   // entry, or NULL on failure (fails if caching is disabled).
   // (|error|, |addrlist|) is the value to set, and |now| is the current
   // timestamp.
-  Entry* Set(const std::string& hostname,
+  Entry* Set(const Key& key,
              int error,
              const AddressList addrlist,
              base::TimeTicks now);
 
   // Returns true if this HostCache can contain no entries.
   bool caching_is_disabled() const {
     return max_entries_ == 0;
   }
 
   // Returns the number of entries in the cache.
@@ skipping 34 matching lines @@
   // Map from hostname (presumably in lowercase canonicalized format) to
   // a resolved result entry.
   EntryMap entries_;
 
   DISALLOW_COPY_AND_ASSIGN(HostCache);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_HOST_CACHE_H_