1 /*
2  * Copyright 2023 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 androidx.datastore.core
18 
19 import kotlin.contracts.ExperimentalContracts
20 import kotlin.contracts.InvocationKind
21 import kotlin.contracts.contract
22 import kotlinx.coroutines.sync.Mutex
23 
24 /**
25  * Provide similar functionality of {@link kotlinx.coroutines.sync.Mutex#withLock} but don't wait
26  * for the lock if unavailable, instead it passes a Boolean into the [block] lambda to indicate if
27  * it is able to get the lock and run [block] immediately.
28  *
29  * [block] is guaranteed to be called once and only once by this function.
30  */
31 @ExperimentalContracts
withTryLocknull32 internal inline fun <R> Mutex.withTryLock(owner: Any? = null, block: (Boolean) -> R): R {
33     contract { callsInPlace(block, InvocationKind.EXACTLY_ONCE) }
34     val locked: Boolean = tryLock(owner)
35     try {
36         return block(locked)
37     } finally {
38         if (locked) {
39             unlock(owner)
40         }
41     }
42 }
43