DnsClient refactoring + features (timeout, suffix search, server rotation).

net/dns/dns_transaction.h

-// Copyright (c) 2011 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_TRANSACTION_H_
-#define NET_DNS_DNS_TRANSACTION_H_
-#pragma once
-
-#include <string>
-#include <vector>
-
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/timer.h"
-#include "base/threading/non_thread_safe.h"
-#include "net/base/completion_callback.h"
-#include "net/base/ip_endpoint.h"
-#include "net/base/net_export.h"
-#include "net/base/net_log.h"
-#include "net/base/rand_callback.h"
-
-namespace net {
-
-class DatagramClientSocket;
-class DnsQuery;
-class DnsResponse;
-class DnsSession;
-
-// Performs a single asynchronous DNS transaction over UDP,
-// which consists of sending out a DNS query, waiting for a response, and
-// returning the response that it matches.
-class NET_EXPORT_PRIVATE DnsTransaction :
-    NON_EXPORTED_BASE(public base::NonThreadSafe) {
- public:
-  typedef base::Callback<void(DnsTransaction*, int)> ResultCallback;
-
-  // Create new transaction using the parameters and state in |session|.
-  // Issues query for name |qname| (in DNS format) type |qtype| and class IN.
-  // Calls |callback| on completion or timeout.
-  // TODO(szym): change dependency to (IPEndPoint, Socket, DnsQuery, callback)
-  DnsTransaction(DnsSession* session,
-                 const base::StringPiece& qname,
-                 uint16 qtype,
-                 const ResultCallback& callback,
-                 const BoundNetLog& source_net_log);
-  ~DnsTransaction();
-
-  const DnsQuery* query() const { return query_.get(); }
-
-  const DnsResponse* response() const { return response_.get(); }
-
-  // Starts the resolution process.  Will return ERR_IO_PENDING and will
-  // notify the caller via |delegate|.  Should only be called once.
-  int Start();
-
- private:
-  enum State {
-    STATE_CONNECT,
-    STATE_CONNECT_COMPLETE,
-    STATE_SEND_QUERY,
-    STATE_SEND_QUERY_COMPLETE,
-    STATE_READ_RESPONSE,
-    STATE_READ_RESPONSE_COMPLETE,
-    STATE_NONE,
-  };
-
-  int DoLoop(int result);
-  void DoCallback(int result);
-  void OnIOComplete(int result);
-
-  int DoConnect();
-  int DoConnectComplete(int result);
-  int DoSendQuery();
-  int DoSendQueryComplete(int result);
-  int DoReadResponse();
-  int DoReadResponseComplete(int result);
-
-  // Fixed number of attempts are made to send a query and read a response,
-  // and at the start of each, a timer is started with increasing delays.
-  void StartTimer(base::TimeDelta delay);
-  void RevokeTimer();
-  void OnTimeout();
-
-  scoped_refptr<DnsSession> session_;
-  IPEndPoint dns_server_;
-  scoped_ptr<DnsQuery> query_;
-  ResultCallback callback_;
-  scoped_ptr<DnsResponse> response_;
-  scoped_ptr<DatagramClientSocket> socket_;
-
-  // Number of retry attempts so far.
-  int attempts_;
-
-  State next_state_;
-  base::OneShotTimer<DnsTransaction> timer_;
-
-  BoundNetLog net_log_;
-
-  DISALLOW_COPY_AND_ASSIGN(DnsTransaction);
-};
-
-}  // namespace net
-
-#endif  // NET_DNS_DNS_TRANSACTION_H_