LoadManager.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2012, 2013 Ripple Labs Inc.
 
    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#ifndef RIPPLE_APP_MAIN_LOADMANAGER_H_INCLUDED
#define RIPPLE_APP_MAIN_LOADMANAGER_H_INCLUDED
 
#include <xrpl/beast/utility/Journal.h>
 
#include <atomic>
#include <memory>
#include <mutex>
#include <thread>
 
namespace ripple {
 
class Application;
 
class LoadManager
{
    LoadManager(Application& app, beast::Journal journal);
 
public:
    LoadManager() = delete;
    LoadManager(LoadManager const&) = delete;
    LoadManager&
    operator=(LoadManager const&) = delete;
 
    ~LoadManager();
 
    // VFALCO NOTE it seems that the stall detector has an "armed" state
    //             to prevent it from going off during program startup if
    //             there's a lengthy initialization operation taking place?
    //
    void
    activateStallDetector();
 
    void
    heartbeat();
 
    //--------------------------------------------------------------------------
 
    void
    start();
 
    void
    stop();
 
private:
    void
    run();
 
private:
    Application& app_;
    beast::Journal const journal_;
 
    std::thread thread_;
    std::mutex mutex_;  // Guards lastHeartbeat_, armed_, cv_
    std::condition_variable cv_;
    bool stop_ = false;
 
    // Detect server stalls
    std::chrono::steady_clock::time_point lastHeartbeat_;
    bool armed_;
 
    friend std::unique_ptr<LoadManager>
    make_LoadManager(Application& app, beast::Journal journal);
};
 
std::unique_ptr<LoadManager>
make_LoadManager(Application& app, beast::Journal journal);
 
}  // namespace ripple
 
#endif