1 /*
2  * Copyright (C) 2024 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 
17 package android.tools
18 
19 interface Trace<Entry : TraceEntry> {
20     val entries: Collection<Entry>
21 
22     /** @return a slice inclusive of both start and end timestamp */
slicenull23     fun slice(startTimestamp: Timestamp, endTimestamp: Timestamp): Trace<Entry>
24 
25     /**
26      * @return an entry that matches exactly [timestamp]
27      * @throws if there is no entry in the trace at [timestamp]
28      */
29     fun getEntryExactlyAt(timestamp: Timestamp): Entry {
30         return entries.firstOrNull { it.timestamp == timestamp }
31             ?: throw RuntimeException("Entry does not exist for timestamp $timestamp")
32     }
33 
34     /**
35      * @return the entry that is "active' at [timestamp]
36      *
37      * ```
38      *         (the entry at [timestamp] or the one before it if no entry exists at [timestamp])
39      * @throws if
40      * ```
41      *
42      * the provided [timestamp] is before all entries in the trace
43      */
getEntryAtnull44     fun getEntryAt(timestamp: Timestamp): Entry {
45         return entries.toList().dropLastWhile { it.timestamp > timestamp }.lastOrNull()
46             ?: error("No entry at or before timestamp $timestamp")
47     }
48 }
49