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/*
* Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
* that can be found in the license/LICENSE.txt file.
*/
package test.utils
import kotlin.test.*
import kotlin.concurrent.thread
import test.io.serializeAndDeserialize
import java.util.*
import java.util.concurrent.ConcurrentLinkedQueue
import java.util.concurrent.ConcurrentHashMap
import java.util.concurrent.CyclicBarrier
import java.util.concurrent.atomic.AtomicBoolean
import java.util.concurrent.atomic.AtomicInteger
class LazyJVMTest {
@Test fun synchronizedLazy() {
val counter = AtomicInteger(0)
val lazy = lazy {
val value = counter.incrementAndGet()
Thread.sleep(16)
value
}
val threads = 3
val barrier = CyclicBarrier(threads)
val accessThreads = List(threads) { thread { barrier.await(); lazy.value } }
accessThreads.forEach { it.join() }
assertEquals(1, counter.get())
}
@Test fun synchronizedLazyRace() {
racyTest(initialize = {
val counter = AtomicInteger(0)
lazy { counter.incrementAndGet() }
},
access = { lazy, _ -> lazy.value },
validate = { result -> result.all { it == 1 } }
)
}
@Test fun externallySynchronizedLazy() {
val counter = AtomicInteger(0)
var initialized: Boolean = false
val runs = ConcurrentHashMap<Int, Boolean>()
val lock = Any()
val initializer = {
val value = counter.incrementAndGet()
runs += (value to initialized)
Thread.sleep(16)
initialized = true
value
}
val lazy1 = lazy(lock, initializer)
val lazy2 = lazy(lock, initializer)
val accessThreads = listOf(lazy1, lazy2).map { thread { it.value } }
accessThreads.forEach { it.join() }
assertEquals(2, counter.get())
@Suppress("NAME_SHADOWING")
for ((counter, initialized) in runs) {
assertEquals(initialized, counter == 2, "Expected uninitialized on first, initialized on second call: initialized=$initialized, counter=$counter")
}
}
@Test fun externallySynchronizedLazyRace() {
val threads = 3
racyTest(threads,
initialize = {
val counter = AtomicInteger(0)
var initialized = false
val initializer = {
(counter.incrementAndGet() to initialized).also {
initialized = true
}
}
val lock = Any()
List(threads) { lazy(lock, initializer) }
},
access = { lazies, runnerIndex -> lazies[runnerIndex].value },
validate = { result -> result.all { (id, initialized) -> initialized == (id != 1) } })
}
@Test fun publishOnceLazy() {
val counter = AtomicInteger(0)
val initialized = AtomicBoolean(false)
val threads = 3
val values = Random().let { r -> List(threads) { 50 + r.nextInt(50) } }
data class Run(val value: Int, val initialized: Boolean)
val runs = ConcurrentLinkedQueue<Run>()
val initializer = {
val id = counter.getAndIncrement()
val value = values[id]
runs += Run(value, initialized.get())
Thread.sleep(value.toLong())
initialized.set(true)
value
}
val lazy = lazy(LazyThreadSafetyMode.PUBLICATION, initializer)
val barrier = CyclicBarrier(threads)
val accessThreads = List(threads) { thread { barrier.await(); lazy.value } }
val result = run { while (!lazy.isInitialized()) /* wait */; lazy.value }
accessThreads.forEach { it.join() }
assertEquals(threads, counter.get())
assertEquals(result, lazy.value, "Value must not change after isInitialized is set: $lazy, runs: $runs")
runs.forEach {
assertFalse(it.initialized, "Expected uninitialized on all initializer executions, runs: $runs")
}
}
@Test fun publishOnceLazyRace() {
racyTest(initialize = { lazy(LazyThreadSafetyMode.PUBLICATION) { Thread.currentThread().id } },
access = { lazy, _ -> lazy.value },
validate = { result -> result.all { v -> v == result[0] } })
}
@Test fun lazyInitializationForcedOnSerialization() {
for (mode in listOf(LazyThreadSafetyMode.SYNCHRONIZED, LazyThreadSafetyMode.PUBLICATION, LazyThreadSafetyMode.NONE)) {
val lazy = lazy(mode) { "initialized" }
assertFalse(lazy.isInitialized())
val lazy2 = serializeAndDeserialize(lazy)
assertTrue(lazy.isInitialized())
assertTrue(lazy2.isInitialized())
assertEquals(lazy.value, lazy2.value)
}
}
private fun <TState : Any, TResult> racyTest(
threads: Int = 3, runs: Int = 5000,
initialize: () -> TState,
access: (TState, runnerIndex: Int) -> TResult,
validate: (List<TResult>) -> Boolean
) {
val runResult = java.util.Collections.synchronizedList(mutableListOf<TResult>())
val invalidResults = mutableListOf<Pair<Int, List<TResult>>>()
lateinit var state: TState
var runId = -1
val barrier = CyclicBarrier(threads) {
if (runId >= 0) {
if (!validate(runResult))
invalidResults.add(runId to runResult.toList())
runResult.clear()
}
state = initialize()
runId += 1
}
val runners = List(threads) { index ->
thread {
barrier.await()
repeat(runs) {
runResult += access(state, index)
barrier.await()
}
}
}
runners.forEach { it.join() }
assertTrue(invalidResults.isEmpty(), invalidResults.joinToString("\n") { (index, result) -> "At run #$index: $result" })
}
}
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