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      1 /*
      2  * libjingle
      3  * Copyright 2011, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #ifndef TALK_XMPP_PINGTASK_H_
     29 #define TALK_XMPP_PINGTASK_H_
     30 
     31 #include "talk/xmpp/xmpptask.h"
     32 #include "webrtc/base/messagehandler.h"
     33 #include "webrtc/base/messagequeue.h"
     34 
     35 namespace buzz {
     36 
     37 // Task to periodically send pings to the server to ensure that the network
     38 // connection is valid, implementing XEP-0199.
     39 //
     40 // This is especially useful on cellular networks because:
     41 // 1. It keeps the connections alive through the cellular network's NATs or
     42 //    proxies.
     43 // 2. It detects when the server has crashed or any other case in which the
     44 //    connection has broken without a fin or reset packet being sent to us.
     45 class PingTask : public buzz::XmppTask, private rtc::MessageHandler {
     46  public:
     47   PingTask(buzz::XmppTaskParentInterface* parent,
     48       rtc::MessageQueue* message_queue, uint32 ping_period_millis,
     49       uint32 ping_timeout_millis);
     50 
     51   virtual bool HandleStanza(const buzz::XmlElement* stanza);
     52   virtual int ProcessStart();
     53 
     54   // Raised if there is no response to a ping within ping_timeout_millis.
     55   // The task is automatically aborted after a timeout.
     56   sigslot::signal0<> SignalTimeout;
     57 
     58  private:
     59   // Implementation of MessageHandler.
     60   virtual void OnMessage(rtc::Message* msg);
     61 
     62   rtc::MessageQueue* message_queue_;
     63   uint32 ping_period_millis_;
     64   uint32 ping_timeout_millis_;
     65   uint32 next_ping_time_;
     66   uint32 ping_response_deadline_; // 0 if the response has been received
     67 };
     68 
     69 } // namespace buzz
     70 
     71 #endif  // TALK_XMPP_PINGTASK_H_
     72