/* -*- 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 { struct JS_PUBLIC_API(TimeBudget) { int64_t budget; explicit TimeBudget(int64_t milliseconds) { budget = milliseconds; } }; struct JS_PUBLIC_API(WorkBudget) { int64_t budget; explicit WorkBudget(int64_t work) { budget = work; } }; /* * 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. */ class JS_PUBLIC_API(SliceBudget) { static const int64_t unlimitedDeadline = INT64_MAX; static const intptr_t unlimitedStartCounter = INTPTR_MAX; bool checkOverBudget(); SliceBudget(); public: // Memory of the originally requested budget. If isUnlimited, neither of // these are in use. If deadline==0, then workBudget is valid. Otherwise // timeBudget is valid. TimeBudget timeBudget; WorkBudget workBudget; int64_t deadline; /* in microseconds */ intptr_t counter; static const intptr_t CounterReset = 1000; static const int64_t UnlimitedTimeBudget = -1; static const int64_t UnlimitedWorkBudget = -1; /* Use to create an unlimited budget. */ static SliceBudget unlimited() { return SliceBudget(); } /* Instantiate as SliceBudget(TimeBudget(n)). */ explicit SliceBudget(TimeBudget time); /* Instantiate as SliceBudget(WorkBudget(n)). */ explicit SliceBudget(WorkBudget work); void makeUnlimited() { deadline = unlimitedDeadline; counter = unlimitedStartCounter; } void step(intptr_t amt = 1) { counter -= amt; } bool isOverBudget() { if (counter > 0) return false; return checkOverBudget(); } bool isWorkBudget() const { return deadline == 0; } bool isTimeBudget() const { return deadline > 0 && !isUnlimited(); } bool isUnlimited() const { return deadline == unlimitedDeadline; } int describe(char* buffer, size_t maxlen) const; }; } // namespace js #endif /* js_SliceBudget_h */