gecko/js/public/SliceBudget.h
2013-12-03 15:53:40 -08:00

58 lines
1.5 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef js_SliceBudget_h
#define js_SliceBudget_h
#include <stdint.h>
namespace js {
/*
* This class records how much work has been done in a given collection slice, so that
* we can return before pausing for too long. Some slices are allowed to run for
* unlimited time, and others are bounded. To reduce the number of gettimeofday
* calls, we only check the time every 1000 operations.
*/
struct JS_PUBLIC_API(SliceBudget)
{
int64_t deadline; /* in microseconds */
intptr_t counter;
static const intptr_t CounterReset = 1000;
static const int64_t Unlimited = 0;
static int64_t TimeBudget(int64_t millis);
static int64_t WorkBudget(int64_t work);
/* Equivalent to SliceBudget(UnlimitedBudget). */
SliceBudget();
/* Instantiate as SliceBudget(Time/WorkBudget(n)). */
SliceBudget(int64_t budget);
void reset() {
deadline = INT64_MAX;
counter = INTPTR_MAX;
}
void step(intptr_t amt = 1) {
counter -= amt;
}
bool checkOverBudget();
bool isOverBudget() {
if (counter >= 0)
return false;
return checkOverBudget();
}
};
} // namespace js
#endif /* js_SliceBudget_h */