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/**
* @file lldeadmantimer.cpp
* @brief Simple deadman-switch timer.
* @author monty@lindenlab.com
*
* $LicenseInfo:firstyear=2013&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2013, Linden Research, Inc.
*
* 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;
* version 2.1 of the License only.
*
* 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
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#include "lldeadmantimer.h"
// *TODO: Currently, this uses lltimer functions for its time
// aspects and this leaks into the apis in the U64s/F64s. Would
// like to perhaps switch this over to TSC register-based timers
// sometime and drop the overhead some more.
// Flag states and their meaning:
// mActive mDone Meaning
// false false Nothing running, no result available
// true false Timer running, no result available
// false true Timer finished, result can be read once
// true true Not allowed
//
LLDeadmanTimer::LLDeadmanTimer(F64 horizon)
: mHorizon(time_type(llmax(horizon, F64(0.0)) * gClockFrequency)),
mActive(false), // If true, a timer is running.
mDone(false), // If true, timer has completed and can be read (once)
mStarted(U64L(0)),
mExpires(U64L(0)),
mStopped(U64L(0)),
mCount(U64L(0))
{}
// static
LLDeadmanTimer::time_type LLDeadmanTimer::getNow()
{
return LLTimer::getCurrentClockCount();
}
void LLDeadmanTimer::start(time_type now)
{
// *TODO: If active, let's complete an existing timer and save
// the result to the side. I think this will be useful later.
// For now, wipe out anything in progress, start fresh.
if (! now)
{
now = LLTimer::getCurrentClockCount();
}
mActive = true;
mDone = false;
mStarted = now;
mExpires = now + mHorizon;
mStopped = now;
mCount = U64L(0);
}
void LLDeadmanTimer::stop(time_type now)
{
if (! mActive)
{
return;
}
if (! now)
{
now = getNow();
}
mStopped = now;
mActive = false;
mDone = true;
}
bool LLDeadmanTimer::isExpired(time_type now, F64 & started, F64 & stopped, U64 & count)
{
if (mActive && ! mDone)
{
if (! now)
{
now = getNow();
}
if (now >= mExpires)
{
// mStopped from ringBell() is the value we want
mActive = false;
mDone = true;
}
}
if (! mDone)
{
return false;
}
started = mStarted * gClockFrequencyInv;
stopped = mStopped * gClockFrequencyInv;
count = mCount;
mDone = false;
return true;
}
void LLDeadmanTimer::ringBell(time_type now, unsigned int count)
{
if (! mActive)
{
return;
}
if (! now)
{
now = getNow();
}
if (now >= mExpires)
{
mActive = false;
mDone = true;
}
else
{
mStopped = now;
mExpires = now + mHorizon;
mCount += count;
}
return;
}
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