1 /*
<lambda>null2 * 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 com.android.intentresolver.util
18
19 import kotlinx.coroutines.async
20 import kotlinx.coroutines.awaitAll
21 import kotlinx.coroutines.coroutineScope
22 import kotlinx.coroutines.sync.withPermit
23 import kotlinx.coroutines.yield
24
25 /** Like [Iterable.map] but executes each [block] invocation in a separate coroutine. */
26 suspend fun <A, B> Iterable<A>.mapParallel(
27 parallelism: Int? = null,
28 block: suspend (A) -> B,
29 ): List<B> =
30 parallelism?.let { permits ->
31 withSemaphore(permits = permits) { mapParallel { withPermit { block(it) } } }
32 }
33 ?: mapParallel(block)
34
35 /** Like [Iterable.map] but executes each [block] invocation in a separate coroutine. */
mapParallelnull36 suspend fun <A, B> Sequence<A>.mapParallel(
37 parallelism: Int? = null,
38 block: suspend (A) -> B,
39 ): List<B> = asIterable().mapParallel(parallelism, block)
40
41 private suspend fun <A, B> Iterable<A>.mapParallel(block: suspend (A) -> B): List<B> =
42 coroutineScope {
43 map {
44 async {
45 yield()
46 block(it)
47 }
48 }
49 .awaitAll()
50 }
51
mapParallelIndexednull52 suspend fun <A, B> Iterable<A>.mapParallelIndexed(
53 parallelism: Int? = null,
54 block: suspend (Int, A) -> B,
55 ): List<B> =
56 parallelism?.let { permits ->
57 withSemaphore(permits = permits) {
58 mapParallelIndexed { idx, item -> withPermit { block(idx, item) } }
59 }
60 } ?: mapParallelIndexed(block)
61
mapParallelIndexednull62 private suspend fun <A, B> Iterable<A>.mapParallelIndexed(block: suspend (Int, A) -> B): List<B> =
63 coroutineScope {
64 mapIndexed { index, item ->
65 async {
66 yield()
67 block(index, item)
68 }
69 }
70 .awaitAll()
71 }
72