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/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <gtest/gtest_prod.h>
#include <stdint.h>
namespace android {
namespace os {
namespace statsd {
/**
* A simple stopwatch to time the duration of condition being true.
*
* The owner of the stopwatch (MetricProducer) is responsible to notify the stopwatch when condition
* changes (start/pause), and when to start a new bucket (a new lap basically). All timestamps
* should be elapsedRealTime in nano seconds.
*
* Keep the timer simple and inline everything. This class is *NOT* thread safe. Caller is
* responsible for thread safety.
*/
class ConditionTimer {
public:
explicit ConditionTimer(bool initCondition, int64_t bucketStartNs) : mCondition(initCondition) {
if (initCondition) {
mLastConditionTrueTimestampNs = bucketStartNs;
}
};
// Tracks how long the condition has been stayed true in the *current* bucket.
// When a new bucket is created, this value will be reset to 0.
int64_t mTimerNs = 0;
// Last elapsed real timestamp when condition turned to true
// When a new bucket is created and the condition is true, then the timestamp is set
// to be the bucket start timestamp.
int64_t mLastConditionTrueTimestampNs = 0;
bool mCondition = false;
int64_t newBucketStart(int64_t nextBucketStartNs) {
if (mCondition) {
mTimerNs += (nextBucketStartNs - mLastConditionTrueTimestampNs);
mLastConditionTrueTimestampNs = nextBucketStartNs;
}
int64_t temp = mTimerNs;
mTimerNs = 0;
return temp;
}
void onConditionChanged(bool newCondition, int64_t timestampNs) {
if (newCondition == mCondition) {
return;
}
mCondition = newCondition;
if (newCondition) {
mLastConditionTrueTimestampNs = timestampNs;
} else {
mTimerNs += (timestampNs - mLastConditionTrueTimestampNs);
}
}
FRIEND_TEST(ConditionTimerTest, TestTimer_Inital_False);
FRIEND_TEST(ConditionTimerTest, TestTimer_Inital_True);
};
} // namespace statsd
} // namespace os
} // namespace android
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