1 /*
2  * Copyright (C) 2022 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package com.android.quicksearchbox
17 
18 import android.os.SystemClock
19 
20 /**
21  * Tracks latency in wall-clock time. Since [.getLatency] returns an `int`, latencies over 2^31 ms
22  * (~ 25 days) cannot be measured. This class uses [SystemClock.uptimeMillis] which does not advance
23  * during deep sleep.
24  */
25 class LatencyTracker {
26   /** Start time, in milliseconds as returned by [SystemClock.uptimeMillis]. */
27   private var mStartTime: Long
28 
29   /** Resets the start time. */
resetnull30   fun reset() {
31     mStartTime = SystemClock.uptimeMillis()
32   }
33 
34   /** Gets the number of milliseconds since the object was created, or [.reset] was called. */
35   val latency: Int
36     get() {
37       val now: Long = SystemClock.uptimeMillis()
38       return (now - mStartTime).toInt()
39     }
40 
41   /** Creates a new latency tracker and sets the start time. */
42   init {
43     mStartTime = SystemClock.uptimeMillis()
44   }
45 }
46