Keep pool of pre-connected DNS sockets

net/dns/dns_socket_pool.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_DNS_DNS_SOCKET_POOL_H_
+#define NET_DNS_DNS_SOCKET_POOL_H_
+
+#include <vector>
+
+#include "base/memory/scoped_ptr.h"
+
+namespace net {
+
+class ClientSocketFactory;
+class DatagramClientSocket;
+class IPEndPoint;
+class NetLog;
+
+class DnsSocketPool {
+ public:
+  virtual ~DnsSocketPool() { }
+
+  static scoped_ptr<DnsSocketPool> CreateDefault(
+      ClientSocketFactory* factory);
+
+  static scoped_ptr<DnsSocketPool> CreateNull(
+      ClientSocketFactory* factory);
+
+  virtual void Initialize(
+      const std::vector<IPEndPoint>* nameservers,
+      NetLog* net_log) = 0;
+
+  virtual scoped_ptr<DatagramClientSocket> AllocateSocket(
+      unsigned server_index) = 0;
+
+  virtual void FreeSocket(
+      unsigned server_index,
+      scoped_ptr<DatagramClientSocket> socket) = 0;
+
+ protected:
+  DnsSocketPool(ClientSocketFactory* socket_factory);
+
+  void InitializeInternal(
+      const std::vector<IPEndPoint>* nameservers,
+      NetLog* net_log);
+
+  scoped_ptr<DatagramClientSocket> CreateConnectedSocket(
+      unsigned server_index);
+
+ private:
+  ClientSocketFactory* socket_factory_;
+  NetLog* net_log_;
+  const std::vector<IPEndPoint>* nameservers_;
+  bool initialized_;
+
+  DISALLOW_COPY_AND_ASSIGN(DnsSocketPool);
+};
+
+} // namespace net
+
+#endif // NET_DNS_DNS_SOCKET_POOL_H_