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/* =========================================================================================
* Copyright © 2013-2017 the kamon project <http://kamon.io/>
*
* 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.
* =========================================================================================
*/
package kamon.util
import java.time.{Instant, ZoneId, Clock => JavaClock}
abstract class Clock extends JavaClock {
def nanos(): Long
def nanosBetween(left: Instant, right: Instant): Long
def toInstant(nanos: Long): Instant
}
object Clock {
private val MillisInSecond = 1000L
private val MicrosInSecond = 1000000L
private val NanosInSecond = 1000000000L
class Default extends Clock {
private val systemClock = JavaClock.systemUTC()
private val (startTimeMillis, startNanoTime) = {
var calibrationIterations = 1000
var millis = System.currentTimeMillis()
var nanos = System.nanoTime()
var isCandidate = false
while(calibrationIterations > 0) {
val currentMillis = System.currentTimeMillis()
val currentNanos = System.nanoTime()
if(isCandidate && millis != currentMillis) {
millis = currentMillis
nanos = currentNanos
calibrationIterations = 0
} else {
if(millis == currentMillis) {
isCandidate = true
} else {
millis = currentMillis
nanos = currentNanos
}
}
calibrationIterations -= 1
}
(millis, nanos)
}
private val startSecondTime = Math.floorDiv(startTimeMillis, MillisInSecond)
private val startSecondNanoOffset = Math.multiplyExact(Math.floorMod(startTimeMillis, MillisInSecond), MicrosInSecond)
override def nanos(): Long =
System.nanoTime()
override def toInstant(nanos: Long): Instant = {
val nanoOffset = nanos - startNanoTime + startSecondNanoOffset
Instant.ofEpochSecond(startSecondTime, nanoOffset)
}
override def instant(): Instant =
toInstant(System.nanoTime())
override def nanosBetween(left: Instant, right: Instant): Long = {
val secsDiff = Math.subtractExact(right.getEpochSecond, left.getEpochSecond)
val totalNanos = Math.multiplyExact(secsDiff, NanosInSecond)
return Math.addExact(totalNanos, right.getNano - left.getNano)
}
override def withZone(zone: ZoneId): JavaClock =
systemClock.withZone(zone)
override def getZone: ZoneId =
systemClock.getZone()
}
}
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