зеркало из https://github.com/mozilla/gecko-dev.git
64 строки
2.1 KiB
C++
64 строки
2.1 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "MainThreadIdlePeriod.h"
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#include "mozilla/Maybe.h"
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#include "mozilla/Preferences.h"
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#include "nsRefreshDriver.h"
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#include "nsThreadUtils.h"
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// The amount of idle time (milliseconds) reserved for a long idle period.
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static const double kLongIdlePeriodMS = 50.0;
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// The minimum amount of time (milliseconds) required for an idle period to be
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// scheduled on the main thread. N.B. layout.idle_period.time_limit adds
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// padding at the end of the idle period, which makes the point in time that we
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// expect to become busy again be:
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// now + kMinIdlePeriodMS + layout.idle_period.time_limit
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static const double kMinIdlePeriodMS = 3.0;
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static const uint32_t kMaxTimerThreadBound = 5; // milliseconds
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static const uint32_t kMaxTimerThreadBoundClamp = 15; // milliseconds
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namespace mozilla {
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NS_IMETHODIMP
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MainThreadIdlePeriod::GetIdlePeriodHint(TimeStamp* aIdleDeadline)
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{
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MOZ_ASSERT(NS_IsMainThread());
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MOZ_ASSERT(aIdleDeadline);
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TimeStamp now = TimeStamp::Now();
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TimeStamp currentGuess =
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now + TimeDuration::FromMilliseconds(kLongIdlePeriodMS);
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currentGuess = nsRefreshDriver::GetIdleDeadlineHint(currentGuess);
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currentGuess = NS_GetTimerDeadlineHintOnCurrentThread(currentGuess, kMaxTimerThreadBound);
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// If the idle period is too small, then just return a null time
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// to indicate we are busy. Otherwise return the actual deadline.
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TimeDuration minIdlePeriod =
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TimeDuration::FromMilliseconds(kMinIdlePeriodMS);
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bool busySoon = currentGuess.IsNull() ||
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(now >= (currentGuess - minIdlePeriod)) ||
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currentGuess < mLastIdleDeadline;
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if (!busySoon) {
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*aIdleDeadline = mLastIdleDeadline = currentGuess;
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}
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return NS_OK;
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}
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/* static */ float
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MainThreadIdlePeriod::GetLongIdlePeriod()
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{
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return kLongIdlePeriodMS;
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}
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} // namespace mozilla
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