gecko-dev/xpcom/threads/InputEventStatistics.h

128 строки
3.4 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */
#if !defined(InputEventStatistics_h_)
#define InputEventStatistics_h_
#include "mozilla/ClearOnShutdown.h"
#include "mozilla/Maybe.h"
#include "mozilla/Preferences.h"
#include "mozilla/TimeStamp.h"
#include "nsTArray.h"
namespace mozilla {
class InputEventStatistics
{
// The default amount of time (milliseconds) required for handling a input
// event.
static const uint16_t sDefaultInputDuration = 1;
// The number of processed input events we use to predict the amount of time
// required to process the following input events.
static const uint16_t sInputCountForPrediction = 9;
// The default maximum and minimum time (milliseconds) we reserve for handling
// input events in each frame.
static const uint16_t sMaxReservedTimeForHandlingInput = 8;
static const uint16_t sMinReservedTimeForHandlingInput = 1;
class TimeDurationCircularBuffer
{
int16_t mSize;
int16_t mCurrentIndex;
nsTArray<TimeDuration> mBuffer;
TimeDuration mTotal;
public:
TimeDurationCircularBuffer(uint32_t aSize, TimeDuration& aDefaultValue)
: mSize(aSize)
, mCurrentIndex(0)
{
mSize = mSize == 0 ? sInputCountForPrediction : mSize;
for (int16_t index = 0; index < mSize; ++index) {
mBuffer.AppendElement(aDefaultValue);
mTotal += aDefaultValue;
}
}
void Insert(TimeDuration& aDuration)
{
mTotal += (aDuration - mBuffer[mCurrentIndex]);
mBuffer[mCurrentIndex++] = aDuration;
if (mCurrentIndex == mSize) {
mCurrentIndex = 0;
}
}
TimeDuration GetMean();
};
UniquePtr<TimeDurationCircularBuffer> mLastInputDurations;
TimeDuration mMaxInputDuration;
TimeDuration mMinInputDuration;
bool mEnable;
// We'd like to have our constructor and destructor be private to enforce our
// singleton, but because UniquePtr needs to be able to destruct our class we
// can't. This is a trick that ensures that we're the only code that can
// construct ourselves: nobody else can access ConstructorCookie and therefore
// nobody else can construct an InputEventStatistics.
struct ConstructorCookie {};
public:
explicit InputEventStatistics(ConstructorCookie&&);
~InputEventStatistics()
{
}
static InputEventStatistics& Get()
{
static UniquePtr<InputEventStatistics> sInstance;
if (!sInstance) {
sInstance = MakeUnique<InputEventStatistics>(ConstructorCookie());
ClearOnShutdown(&sInstance);
}
return *sInstance;
}
void UpdateInputDuration(TimeDuration aDuration)
{
if (!mEnable) {
return;
}
mLastInputDurations->Insert(aDuration);
}
TimeStamp GetInputHandlingStartTime(uint32_t aInputCount);
void SetEnable(bool aEnable)
{
mEnable = aEnable;
}
};
class MOZ_RAII AutoTimeDurationHelper final
{
public:
AutoTimeDurationHelper()
{
mStartTime = TimeStamp::Now();
}
~AutoTimeDurationHelper()
{
InputEventStatistics::Get().UpdateInputDuration(TimeStamp::Now() - mStartTime);
}
private:
TimeStamp mStartTime;
};
} // namespace mozilla
#endif // InputEventStatistics_h_