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/*
* Copyright (C) 2013 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "Watchdog.h"
#include "CallFrame.h"
#include <wtf/CurrentTime.h>
#include <wtf/MathExtras.h>
namespace JSC {
#define NO_LIMIT std::numeric_limits<double>::infinity()
Watchdog::Watchdog()
: m_timerDidFire(false)
, m_didFire(false)
, m_limit(NO_LIMIT)
, m_startTime(0)
, m_elapsedTime(0)
, m_reentryCount(0)
, m_isStopped(true)
, m_callback(0)
, m_callbackData1(0)
, m_callbackData2(0)
{
initTimer();
}
Watchdog::~Watchdog()
{
ASSERT(!isArmed());
stopCountdown();
destroyTimer();
}
void Watchdog::setTimeLimit(VM& vm, double limit,
ShouldTerminateCallback callback, void* data1, void* data2)
{
bool wasEnabled = isEnabled();
if (!m_isStopped)
stopCountdown();
m_didFire = false; // Reset the watchdog.
m_limit = limit;
m_callback = callback;
m_callbackData1 = data1;
m_callbackData2 = data2;
// If this is the first time that timeout is being enabled, then any
// previously JIT compiled code will not have the needed polling checks.
// Hence, we need to flush all the pre-existing compiled code.
//
// However, if the timeout is already enabled, and we're just changing the
// timeout value, then any existing JITted code will have the appropriate
// polling checks. Hence, there is no need to re-do this flushing.
if (!wasEnabled) {
// And if we've previously compiled any functions, we need to revert
// them because they don't have the needed polling checks yet.
vm.releaseExecutableMemory();
}
startCountdownIfNeeded();
}
bool Watchdog::didFire(ExecState* exec)
{
if (m_didFire)
return true;
if (!m_timerDidFire)
return false;
m_timerDidFire = false;
stopCountdown();
double currentTime = currentCPUTime();
double deltaTime = currentTime - m_startTime;
double totalElapsedTime = m_elapsedTime + deltaTime;
if (totalElapsedTime > m_limit) {
// Case 1: the allowed CPU time has elapsed.
// If m_callback is not set, then we terminate by default.
// Else, we let m_callback decide if we should terminate or not.
bool needsTermination = !m_callback
|| m_callback(exec, m_callbackData1, m_callbackData2);
if (needsTermination) {
m_didFire = true;
return true;
}
// The m_callback may have set a new limit. So, we may need to restart
// the countdown.
startCountdownIfNeeded();
} else {
// Case 2: the allowed CPU time has NOT elapsed.
// Tell the timer to alarm us again when it thinks we've reached the
// end of the allowed time.
double remainingTime = m_limit - totalElapsedTime;
m_elapsedTime = totalElapsedTime;
m_startTime = currentTime;
startCountdown(remainingTime);
}
return false;
}
bool Watchdog::isEnabled()
{
return (m_limit != NO_LIMIT);
}
void Watchdog::fire()
{
m_didFire = true;
}
void Watchdog::arm()
{
m_reentryCount++;
if (m_reentryCount == 1)
startCountdownIfNeeded();
}
void Watchdog::disarm()
{
ASSERT(m_reentryCount > 0);
if (m_reentryCount == 1)
stopCountdown();
m_reentryCount--;
}
void Watchdog::startCountdownIfNeeded()
{
if (!m_isStopped)
return; // Already started.
if (!isArmed())
return; // Not executing JS script. No need to start.
if (isEnabled()) {
m_elapsedTime = 0;
m_startTime = currentCPUTime();
startCountdown(m_limit);
}
}
void Watchdog::startCountdown(double limit)
{
ASSERT(m_isStopped);
m_isStopped = false;
startTimer(limit);
}
void Watchdog::stopCountdown()
{
if (m_isStopped)
return;
stopTimer();
m_isStopped = true;
}
Watchdog::Scope::Scope(Watchdog& watchdog)
: m_watchdog(watchdog)
{
m_watchdog.arm();
}
Watchdog::Scope::~Scope()
{
m_watchdog.disarm();
}
} // namespace JSC
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