1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef NET_DNS_DNS_SOCKET_POOL_H_ 6 #define NET_DNS_DNS_SOCKET_POOL_H_ 7 8 #include <vector> 9 10 #include "base/memory/scoped_ptr.h" 11 #include "net/base/net_export.h" 12 #include "net/base/net_log.h" 13 14 namespace net { 15 16 class ClientSocketFactory; 17 class DatagramClientSocket; 18 class IPEndPoint; 19 class NetLog; 20 class StreamSocket; 21 22 // A DnsSocketPool is an abstraction layer around a ClientSocketFactory that 23 // allows preallocation, reuse, or other strategies to manage sockets connected 24 // to DNS servers. 25 class NET_EXPORT_PRIVATE DnsSocketPool { 26 public: ~DnsSocketPool()27 virtual ~DnsSocketPool() { } 28 29 // Creates a DnsSocketPool that implements the default strategy for managing 30 // sockets. (This varies by platform; see DnsSocketPoolImpl in 31 // dns_socket_pool.cc for details.) 32 static scoped_ptr<DnsSocketPool> CreateDefault( 33 ClientSocketFactory* factory); 34 35 // Creates a DnsSocketPool that implements a "null" strategy -- no sockets are 36 // preallocated, allocation requests are satisfied by calling the factory 37 // directly, and returned sockets are deleted immediately. 38 static scoped_ptr<DnsSocketPool> CreateNull( 39 ClientSocketFactory* factory); 40 41 // Initializes the DnsSocketPool. |nameservers| is the list of nameservers 42 // for which the DnsSocketPool will manage sockets; |net_log| is the NetLog 43 // used when constructing sockets with the factory. 44 // 45 // Initialize may not be called more than once, and must be called before 46 // calling AllocateSocket or FreeSocket. 47 virtual void Initialize( 48 const std::vector<IPEndPoint>* nameservers, 49 NetLog* net_log) = 0; 50 51 // Allocates a socket that is already connected to the nameserver referenced 52 // by |server_index|. May return a scoped_ptr to NULL if no sockets are 53 // available to reuse and the factory fails to produce a socket (or produces 54 // one on which Connect fails). 55 virtual scoped_ptr<DatagramClientSocket> AllocateSocket( 56 unsigned server_index) = 0; 57 58 // Frees a socket allocated by AllocateSocket. |server_index| must be the 59 // same index passed to AllocateSocket. 60 virtual void FreeSocket( 61 unsigned server_index, 62 scoped_ptr<DatagramClientSocket> socket) = 0; 63 64 // Creates a StreamSocket from the factory for a transaction over TCP. These 65 // sockets are not pooled. 66 scoped_ptr<StreamSocket> CreateTCPSocket( 67 unsigned server_index, 68 const NetLog::Source& source); 69 70 protected: 71 DnsSocketPool(ClientSocketFactory* socket_factory); 72 73 void InitializeInternal( 74 const std::vector<IPEndPoint>* nameservers, 75 NetLog* net_log); 76 77 scoped_ptr<DatagramClientSocket> CreateConnectedSocket( 78 unsigned server_index); 79 80 private: 81 ClientSocketFactory* socket_factory_; 82 NetLog* net_log_; 83 const std::vector<IPEndPoint>* nameservers_; 84 bool initialized_; 85 86 DISALLOW_COPY_AND_ASSIGN(DnsSocketPool); 87 }; 88 89 } // namespace net 90 91 #endif // NET_DNS_DNS_SOCKET_POOL_H_ 92