/usr/include/ola/network/HealthCheckedConnection.h is in libola-dev 0.10.5.nojsmin-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 | /*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* HealthCheckedConnection.h
* Copyright (C) 2012 Simon Newton
*
* This class adds health checking to a connection, which ensures that the
* connection is able to transfer data in a timely manner. The implementation
* is pretty simple: we define a heart beat interval I, which *must* be the
* same at both ends of the connection. Every I seconds, both ends send a
* heart beat message and if either end doesn't receive a heart beat in
* 2.5 * I, the connection is deemed dead, and the connection is closed.
*
* This class provides the basic health check mechanism, the sub class is left
* to define the format of the heartbeat message.
*
* To use this health checked channel, subclass HealthCheckedConnection, and
* provide the SendHeartbeat() and HeartbeatTimeout methods.
*
* There are some additional features:
* - Some receivers may want to stop reading from a connection under some
* circumstances (e.g. flow control). Before this happens, call PauseTimer()
* to pause the rx timer, otherwise the channel will be marked unhealthy. Once
* reading is resumed called ResumeTimer();
* - Some protocols may want to piggyback heartbeats on other messages, or
* even count any message as a heartbeat. When such a message is received, be
* sure to call HeartbeatReceived() which will update the timer.
*/
#ifndef INCLUDE_OLA_NETWORK_HEALTHCHECKEDCONNECTION_H_
#define INCLUDE_OLA_NETWORK_HEALTHCHECKEDCONNECTION_H_
#include <ola/Callback.h>
#include <ola/Clock.h>
#include <ola/base/Macro.h>
#include <ola/thread/SchedulerInterface.h>
namespace ola {
namespace network {
/**
* An class that provides health checking for a connection.
* The subclasses implement the SendHeartbeat and HeartbeatTimeout methods.
*/
class HealthCheckedConnection {
public:
HealthCheckedConnection(ola::thread::SchedulerInterface *scheduler,
const ola::TimeInterval timeout_interval);
virtual ~HealthCheckedConnection();
/**
* Setup the health checked channel
*/
bool Setup();
// Sending methods
//-----------------------------
/*
* Subclasses implement this to send a health check
*/
virtual void SendHeartbeat() = 0;
/**
* Call this when a heartbeat is piggybacked on another message. This
* prevents sending heatbeats unless necessary.
*/
void HeartbeatSent();
// Receiving methods
//-----------------------------
// Call this method every time a valid health check is received.
void HeartbeatReceived();
/*
* This pauses the timer which checks for heartbeats. Call this if you stop
* reading from the socket for any reason.
*/
void PauseTimer();
/**
* Resume the health check timer. Call this when reading is resumed.
*/
void ResumeTimer();
protected:
/**
* This is called when we don't receive a health check within the interval.
*/
virtual void HeartbeatTimeout() = 0;
private:
ola::thread::SchedulerInterface *m_scheduler;
ola::TimeInterval m_heartbeat_interval;
ola::thread::timeout_id m_send_timeout_id;
ola::thread::timeout_id m_receive_timeout_id;
bool SendNextHeartbeat();
void UpdateReceiveTimer();
void InternalHeartbeatTimeout();
DISALLOW_COPY_AND_ASSIGN(HealthCheckedConnection);
};
} // namespace network
} // namespace ola
#endif // INCLUDE_OLA_NETWORK_HEALTHCHECKEDCONNECTION_H__
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