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//*********************************************************
//
// Copyright (c) Microsoft. All rights reserved.
// This code is licensed under the MIT License (MIT).
// THIS CODE IS PROVIDED *AS IS* WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY
// IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR
// PURPOSE, MERCHANTABILITY, OR NON-INFRINGEMENT.
//
//*********************************************************
#include "stdafx.h"
#include "Metering.h"
#include <assert.h>
#include "RpcInterface_h.h"
using namespace RpcServer;
//
// Thread pool callback method for metering worker
//
void CALLBACK MeteringWorkerTpCallback(
_In_ PTP_CALLBACK_INSTANCE /*iTimerInstance*/,
_In_ PVOID pContext,
_In_ PTP_TIMER /*pTimer*/)
{
Metering *metering = static_cast<Metering *>(pContext);
if (metering != nullptr)
{
// Run the metering worker for this instance of metering
metering->MeteringWorker();
}
}
//
// ctor for Metering
//
Metering::Metering(
_In_ __int64 period)
{
tpTimer = CreateThreadpoolTimer(::MeteringWorkerTpCallback, this, nullptr);
// TODO: Handle if CreateThreadpoolTimer fails i.e tpTimer == nullptr
samplePeriod = period;
event = CreateEvent(
nullptr, // default security attributes
FALSE, // auto-reset event object
FALSE, // initial state is nonsignaled
nullptr); // unnamed object
}
//
// dtor for Metering
//
Metering::~Metering()
{
if (tpTimer != nullptr)
{
// How to close threadpool timer when there are outstanding callbacks:
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms682040(v=vs.85).aspx
SetThreadpoolTimer(tpTimer, nullptr, 0, 0);
WaitForThreadpoolTimerCallbacks(tpTimer, true);
CloseThreadpoolTimer(tpTimer);
tpTimer = nullptr;
}
CloseHandle(event);
}
//
// Set the lowest sample period
//
void Metering::SetSamplePeriod(_In_ __int64 period)
{
if (period < 1)
{
// Don't allow 0 (too fast) or negative numbers.
period = 1;
}
if (period > 1000)
{
// Don't let the period be too long, or we will be
// slow to shut down.
period = 1000;
}
samplePeriod = period;
}
//
// Get last known metering data
//
__int64 Metering::GetMeteringData() const
{
return _data;
}
//
// Metering worker that updates metering data
//
void Metering::MeteringWorker()
{
// Get the value from the imaginary driver and update the data
_data = GetTickCount();
SetEvent(event);
}
//
// Set the thread poot timer and wait for metering data.
//
void Metering::WaitForMeteringData() const
{
ULARGE_INTEGER ulDueTime;
FILETIME FileDueTime;
ulDueTime.QuadPart = static_cast<ULONGLONG>(-(1 * 10 * 1000 * samplePeriod));
FileDueTime.dwHighDateTime = ulDueTime.HighPart;
FileDueTime.dwLowDateTime = ulDueTime.LowPart;
SetThreadpoolTimer(tpTimer,
&FileDueTime,
0,
0);
WaitForSingleObject(event, INFINITE);
}
void Metering::StartMetering(
_In_ __int64 samplePeriod,
_In_ __int64 context)
{
stopMeteringRequested = false;
SetSamplePeriod(samplePeriod);
while (true)
{
WaitForMeteringData();
if (stopMeteringRequested || ShutdownRequested)
{
break;
}
MeteringDataEvent(GetMeteringData(), context);
}
}
void Metering::StopMetering()
{
stopMeteringRequested = true;
}
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