temporal realization of SmartKeyRWLocker

coroutines/src/commonMain/kotlin/dev/inmo/micro_utils/coroutines/SmartKeyRWLocker.kt

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+package dev.inmo.micro_utils.coroutines
+
+import kotlinx.coroutines.sync.withLock
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.InvocationKind
+import kotlin.contracts.contract
+
+class SmartKeyRWLocker<T>(
+    private val perKeyReadPermits: Int = Int.MAX_VALUE
+) {
+    private val internalRWLocker = SmartRWLocker()
+    private val lockers = mutableMapOf<T, SmartRWLocker>()
+
+    private fun allocateLockerWithoutLock(key: T) = lockers.getOrPut(key) {
+        SmartRWLocker(perKeyReadPermits)
+    }
+
+    suspend fun writeMutex(key: T): SmartMutex.Immutable = internalRWLocker.withReadAcquire {
+        allocateLockerWithoutLock(key).writeMutex
+    }
+    suspend fun readSemaphore(key: T): SmartSemaphore.Immutable = internalRWLocker.withReadAcquire {
+        allocateLockerWithoutLock(key).readSemaphore
+    }
+    fun writeMutexOrNull(key: T): SmartMutex.Immutable? = lockers[key] ?.writeMutex
+    fun readSemaphoreOrNull(key: T): SmartSemaphore.Immutable? = lockers[key] ?.readSemaphore
+
+    suspend fun acquireRead(key: T) {
+        internalRWLocker.withReadAcquire {
+            val locker = allocateLockerWithoutLock(key)
+            locker.acquireRead()
+        }
+    }
+    suspend fun releaseRead(key: T): Boolean {
+        return internalRWLocker.withReadAcquire {
+            lockers[key]
+        } ?.releaseRead() == true
+    }
+
+    suspend fun lockWrite(key: T) {
+        internalRWLocker.withWriteLock {
+            val locker = allocateLockerWithoutLock(key)
+            locker.lockWrite()
+        }
+    }
+    suspend fun unlockWrite(key: T): Boolean {
+        return internalRWLocker.withWriteLock {
+            lockers[key]
+        } ?.unlockWrite() == true
+    }
+    fun isWriteLocked(key: T): Boolean = lockers[key] ?.writeMutex ?.isLocked == true
+}
+
+@OptIn(ExperimentalContracts::class)
+suspend inline fun <T, R> SmartKeyRWLocker<T>.withReadAcquire(key: T, action: () -> R): R {
+    contract {
+        callsInPlace(action, InvocationKind.EXACTLY_ONCE)
+    }
+
+    acquireRead(key)
+    try {
+        return action()
+    } finally {
+        releaseRead(key)
+    }
+}
+
+@OptIn(ExperimentalContracts::class)
+suspend inline fun <T, R> SmartKeyRWLocker<T>.withWriteLock(key: T, action: () -> R): R {
+    contract {
+        callsInPlace(action, InvocationKind.EXACTLY_ONCE)
+    }
+
+    lockWrite(key)
+    try {
+        return action()
+    } finally {
+        unlockWrite(key)
+    }
+}

coroutines/src/commonTest/kotlin/RealTimeOut.kt

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+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import kotlinx.coroutines.withTimeout
+import kotlin.time.Duration
+
+suspend fun <T> realWithTimeout(time: Duration, block: suspend () -> T): T {
+    return withContext(Dispatchers.Default.limitedParallelism(1)) {
+        withTimeout(time) {
+            block()
+        }
+    }
+}

coroutines/src/commonTest/kotlin/SmartKeyRWLockerTests.kt

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+import dev.inmo.micro_utils.coroutines.*
+import kotlinx.coroutines.*
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFails
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+import kotlin.time.Duration.Companion.milliseconds
+import kotlin.time.Duration.Companion.seconds
+
+class SmartKeyRWLockerTests {
+    @Test
+    fun lockKeyFailedOnGlobalLockTest() = runTest {
+        val locker = SmartKeyRWLocker<String>()
+        val testKey = "test"
+        locker.lockWrite()
+
+        assertTrue { locker.isWriteLocked() }
+
+        assertFails {
+            realWithTimeout(1.seconds) {
+                locker.lockWrite(testKey)
+            }
+        }
+        assertFalse { locker.isWriteLocked(testKey) }
+
+        locker.unlockWrite()
+        assertFalse { locker.isWriteLocked() }
+
+        realWithTimeout(1.seconds) {
+            locker.lockWrite(testKey)
+        }
+        assertTrue { locker.isWriteLocked(testKey) }
+        assertTrue { locker.unlockWrite(testKey) }
+        assertFalse { locker.isWriteLocked(testKey) }
+    }
+    @Test
+    fun readsBlockingGlobalWrite() = runTest {
+        val locker = SmartKeyRWLocker<String>()
+
+        val testKeys = (0 until 100).map { "test$it" }
+
+        for (i in testKeys.indices) {
+            val it = testKeys[i]
+            locker.acquireRead(it)
+            val previous = testKeys.take(i)
+            val next = testKeys.drop(i + 1)
+
+            previous.forEach {
+                assertTrue { locker.readSemaphoreOrNull(it) ?.freePermits == Int.MAX_VALUE - 1 }
+            }
+            next.forEach {
+                assertTrue { locker.readSemaphoreOrNull(it) ?.freePermits == null }
+            }
+        }
+
+        for (i in testKeys.indices) {
+            val it = testKeys[i]
+            assertFails {
+                realWithTimeout(13.milliseconds) { locker.lockWrite() }
+            }
+            realWithTimeout(1.seconds) { locker.acquireRead() }
+            locker.releaseRead()
+            assertTrue { locker.readSemaphore().freePermits == Int.MAX_VALUE }
+
+            locker.releaseRead(it)
+        }
+
+        realWithTimeout(1.seconds) { locker.lockWrite() }
+        assertFails {
+            realWithTimeout(13.milliseconds) { locker.acquireRead() }
+        }
+        assertTrue { locker.unlockWrite() }
+        assertTrue { locker.readSemaphore().freePermits == Int.MAX_VALUE }
+    }
+}