The Tor Browser: js/public/SliceBudget.h@925c144e1f1f

     1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-

     2  * vim: set ts=8 sts=4 et sw=4 tw=99:

     3  * This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 #ifndef js_SliceBudget_h

     8 #define js_SliceBudget_h

    10 #include <stdint.h>

    12 namespace js {

    14 /*

    15  * This class records how much work has been done in a given collection slice, so that

    16  * we can return before pausing for too long. Some slices are allowed to run for

    17  * unlimited time, and others are bounded. To reduce the number of gettimeofday

    18  * calls, we only check the time every 1000 operations.

    19  */

    20 struct JS_PUBLIC_API(SliceBudget)

    21 {

    22     int64_t deadline; /* in microseconds */

    23     intptr_t counter;

    25     static const intptr_t CounterReset = 1000;

    27     static const int64_t Unlimited = 0;

    28     static int64_t TimeBudget(int64_t millis);

    29     static int64_t WorkBudget(int64_t work);

    31     /* Equivalent to SliceBudget(UnlimitedBudget). */

    32     SliceBudget();

    34     /* Instantiate as SliceBudget(Time/WorkBudget(n)). */

    35     SliceBudget(int64_t budget);

    37     void reset() {

    38         deadline = INT64_MAX;

    39         counter = INTPTR_MAX;

    40     }

    42     void step(intptr_t amt = 1) {

    43         counter -= amt;

    44     }

    46     bool checkOverBudget();

    48     bool isOverBudget() {

    49         if (counter >= 0)

    50             return false;

    51         return checkOverBudget();

    52     }

    53 };

    55 } // namespace js

    57 #endif /* js_SliceBudget_h */

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