start 0.18.1 and add SmartMutex

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.18.1
+
+* `Coroutines`:
+    * Add `SmartMutex`
+
 ## 0.18.0
 
 **ALL PREVIOUSLY DEPRECATED FUNCTIONALITY HAVE BEEN REMOVED**

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

@@ -0,0 +1,136 @@
+package dev.inmo.micro_utils.coroutines
+
+import kotlinx.coroutines.currentCoroutineContext
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.InvocationKind
+import kotlin.contracts.contract
+
+/**
+ * It is interface which will work like classic [Mutex], but in difference have [lockStateFlow] for listening of the
+ * [SmartMutex] state.
+ *
+ * There is [Mutable] and [Immutable] realizations. In case you are owner and manager current state of lock, you need
+ * [Mutable] [SmartMutex]. Otherwise, [Immutable].
+ *
+ * Any [Mutable] [SmartMutex] may produce its [Immutable] variant which will contains [lockStateFlow] equal to its
+ * [Mutable] creator
+ */
+sealed interface SmartMutex {
+    val lockStateFlow: StateFlow<Boolean>
+
+    /**
+     * * True - locked
+     * * False - unlocked
+     */
+    val isLocked: Boolean
+        get() = lockStateFlow.value
+
+    /**
+     * Immutable variant of [SmartMutex]. In fact will depend on the owner of [lockStateFlow]
+     */
+    class Immutable(override val lockStateFlow: StateFlow<Boolean>) : SmartMutex
+
+    /**
+     * Mutable variant of [SmartMutex]. With that variant you may [lock] and [unlock]. Besides, you may create
+     * [Immutable] variant of [this] instance with [immutable] factory
+     *
+     * @param locked Preset state of [isLocked] and its internal [_lockStateFlow]
+     */
+    class Mutable(locked: Boolean = false) : SmartMutex {
+        private val _lockStateFlow = MutableStateFlow<Boolean>(locked)
+        override val lockStateFlow: StateFlow<Boolean> = _lockStateFlow.asStateFlow()
+
+        private val internalChangesMutex = Mutex()
+
+        fun immutable() = Immutable(lockStateFlow)
+
+        /**
+         * Holds call until this [SmartMutex] will be re-locked. That means that while [isLocked] == true, [holds] will
+         * wait for [isLocked] == false and then try to lock
+         */
+        suspend fun lock() {
+            do {
+                waitUnlock()
+                val shouldContinue = internalChangesMutex.withLock {
+                    if (_lockStateFlow.value) {
+                        true
+                    } else {
+                        _lockStateFlow.value = true
+                        false
+                    }
+                }
+            } while (shouldContinue && currentCoroutineContext().isActive)
+        }
+
+        /**
+         * Will try to lock this [SmartMutex] immediataly
+         *
+         * @return True if lock was successful. False otherwise
+         */
+        suspend fun tryLock(): Boolean {
+            return if (!_lockStateFlow.value) {
+                internalChangesMutex.withLock {
+                    if (!_lockStateFlow.value) {
+                        _lockStateFlow.value = true
+                        true
+                    } else {
+                        false
+                    }
+                }
+            } else {
+                false
+            }
+        }
+
+        /**
+         * If [isLocked] == true - will change it to false and return true. If current call will not unlock this
+         * [SmartMutex] - false
+         */
+        suspend fun unlock(): Boolean {
+            return if (_lockStateFlow.value) {
+                internalChangesMutex.withLock {
+                    if (_lockStateFlow.value) {
+                        _lockStateFlow.value = false
+                        true
+                    } else {
+                        false
+                    }
+                }
+            } else {
+                false
+            }
+        }
+    }
+}
+
+/**
+ * Will call [SmartMutex.Mutable.lock], then execute [action] and return the result after [SmartMutex.Mutable.unlock]
+ */
+@OptIn(ExperimentalContracts::class)
+suspend inline fun <T> SmartMutex.Mutable.withLock(action: () -> T): T {
+    contract {
+        callsInPlace(action, InvocationKind.EXACTLY_ONCE)
+    }
+
+    lock()
+    try {
+        return action()
+    } finally {
+        unlock()
+    }
+}
+
+/**
+ * Will wait until the [SmartMutex.lockStateFlow] of [this] instance will be false.
+ *
+ * Anyway, after the end of this block there are no any guaranties that [SmartMutex.isLocked] == false due to the fact
+ * that some other parties may lock it again
+ */
+suspend fun SmartMutex.waitUnlock() = lockStateFlow.first { !it }

gradle.properties

@@ -14,5 +14,5 @@ crypto_js_version=4.1.1
 # Project data
 
 group=dev.inmo
-version=0.18.0
+version=0.18.1
-android_code_version=191
+android_code_version=192