updates in FSM

fsm/common/build.gradle

@@ -10,6 +10,7 @@ kotlin {
     sourceSets {
         commonMain {
             dependencies {
+                api project(":micro_utils.common")
                 api project(":micro_utils.coroutines")
             }
         }

fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/StatesMachine.kt

@@ -1,8 +1,11 @@
 package dev.inmo.micro_utils.fsm.common
 
-import dev.inmo.micro_utils.coroutines.launchSafelyWithoutExceptions
-import dev.inmo.micro_utils.coroutines.subscribeSafelyWithoutExceptions
+import dev.inmo.micro_utils.common.Optional
+import dev.inmo.micro_utils.common.onPresented
+import dev.inmo.micro_utils.coroutines.*
 import kotlinx.coroutines.*
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 
 /**
  * Default [StatesMachine] may [startChain] and use inside logic for handling [State]s. By default you may use
@@ -42,17 +45,53 @@ interface StatesMachine<T : State> : StatesHandler<T, T> {
 
 /**
  * Default realization of [StatesMachine]. It uses [statesManager] for incapsulation of [State]s storing and contexts
- * resolving, and uses [launchStateHandling] for [State] handling
+ * resolving, and uses [launchStateHandling] for [State] handling.
+ *
+ * This class suppose to be extended in case you wish some custom behaviour inside of [launchStateHandling], for example
  */
-class DefaultStatesMachine <T: State>(
-    private val statesManager: StatesManager<T>,
-    private val handlers: List<CheckableHandlerHolder<in T, T>>
+open class DefaultStatesMachine <T: State>(
+    protected val statesManager: StatesManager<T>,
+    protected val handlers: List<CheckableHandlerHolder<in T, T>>,
 ) : StatesMachine<T> {
     /**
      * Will call [launchStateHandling] for state handling
      */
     override suspend fun StatesMachine<in T>.handleState(state: T): T? = launchStateHandling(state, handlers)
 
+    /**
+     * This
+     */
+    protected val statesJobs = mutableMapOf<T, Job>()
+    protected val statesJobsMutex = Mutex()
+
+    protected open suspend fun performUpdate(state: T) {
+        val newState = launchStateHandling(state, handlers)
+        if (newState != null) {
+            statesManager.update(state, newState)
+        } else {
+            statesManager.endChain(state)
+        }
+    }
+
+    open suspend fun performStateUpdate(previousState: Optional<T>, actualState: T, scope: CoroutineScope) {
+        statesJobsMutex.withLock {
+            statesJobs[actualState] ?.cancel()
+            statesJobs[actualState] = scope.launch {
+                performUpdate(actualState)
+            }.also { job ->
+                job.invokeOnCompletion { _ ->
+                    scope.launch {
+                        statesJobsMutex.withLock {
+                            if (statesJobs[actualState] == job) {
+                                statesJobs.remove(actualState)
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
     /**
      * Launch handling of states. On [statesManager] [StatesManager.onStartChain],
      * [statesManager] [StatesManager.onChainStateUpdated] will be called lambda with performing of state. If
@@ -60,23 +99,15 @@ class DefaultStatesMachine <T: State>(
      * [StatesManager.endChain].
      */
     override fun start(scope: CoroutineScope): Job = scope.launchSafelyWithoutExceptions {
-        val statePerformer: suspend (T) -> Unit = { state: T ->
-            val newState = launchStateHandling(state, handlers)
-            if (newState != null) {
-                statesManager.update(state, newState)
-            } else {
-                statesManager.endChain(state)
-            }
-        }
         statesManager.onStartChain.subscribeSafelyWithoutExceptions(this) {
-            launch { statePerformer(it) }
+            launch { performStateUpdate(Optional.absent(), it, scope.LinkedSupervisorScope()) }
         }
         statesManager.onChainStateUpdated.subscribeSafelyWithoutExceptions(this) {
-            launch { statePerformer(it.second) }
+            launch { performStateUpdate(Optional.presented(it.first), it.second, scope.LinkedSupervisorScope()) }
         }
 
         statesManager.getActiveStates().forEach {
-            launch { statePerformer(it) }
+            launch { performStateUpdate(Optional.absent(), it, scope.LinkedSupervisorScope()) }
         }
     }
 

fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/UpdatableStatesMachine.kt

@@ -0,0 +1,57 @@
+package dev.inmo.micro_utils.fsm.common
+
+import dev.inmo.micro_utils.common.*
+import kotlinx.coroutines.*
+import kotlinx.coroutines.sync.withLock
+
+/**
+ * This extender of [StatesMachine] interface declare one new function [updateChain]. Realizations of this interface
+ * must be able to perform update of chain in internal [StatesManager]
+ */
+interface UpdatableStatesMachine<T : State> : StatesMachine<T> {
+    /**
+     * Update chain with current state equal to [currentState] with [newState]. Behaviour of this update preforming
+     * in cases when [currentState] does not exist in [StatesManager] must be declared inside of realization of
+     * [StatesManager.update] function
+     */
+    suspend fun updateChain(currentState: T, newState: T)
+}
+
+open class DefaultUpdatableStatesMachine<T : State>(
+    statesManager: StatesManager<T>,
+    handlers: List<CheckableHandlerHolder<in T, T>>,
+
+) : DefaultStatesMachine<T>(
+    statesManager,
+    handlers
+), UpdatableStatesMachine<T> {
+    protected val jobsStates = mutableMapOf<Job, T>()
+
+    override suspend fun performStateUpdate(previousState: Optional<T>, actualState: T, scope: CoroutineScope) {
+        statesJobsMutex.withLock {
+            statesJobs[actualState] ?.cancel()
+            val job = previousState.mapOnPresented {
+                statesJobs.remove(it)
+            } ?: scope.launch {
+                performUpdate(actualState)
+            }.also { job ->
+                job.invokeOnCompletion { _ ->
+                    scope.launch {
+                        statesJobsMutex.withLock {
+                            statesJobs.remove(
+                                jobsStates[job] ?: return@withLock
+                            )
+                        }
+                    }
+                }
+            }
+            jobsStates.remove(job)
+            statesJobs[actualState] = job
+            jobsStates[job] = actualState
+        }
+    }
+
+    override suspend fun updateChain(currentState: T, newState: T) {
+        statesManager.update(currentState, newState)
+    }
+}

fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/dsl/FSMBuilder.kt

@@ -7,6 +7,14 @@ import kotlin.reflect.KClass
 
 class FSMBuilder<T : State>(
     var statesManager: StatesManager<T> = DefaultStatesManager(InMemoryDefaultStatesManagerRepo()),
+    val fsmBuilder: (states: List<CheckableHandlerHolder<T, T>>, defaultHandler: StatesHandler<T, T>?) -> StatesMachine<T> = { states, defaultHandler ->
+        StatesMachine(
+            statesManager,
+            states.let { list ->
+                defaultHandler ?.let { list + it.holder { true } } ?: list
+            }
+        )
+    },
     var defaultStateHandler: StatesHandler<T, T>? = StatesHandler { null }
 ) {
     private var states = mutableListOf<CheckableHandlerHolder<T, T>>()
@@ -42,12 +50,7 @@ class FSMBuilder<T : State>(
         add(filter, handler)
     }
 
-    fun build() = StatesMachine(
-        statesManager,
-        states.toList().let { list ->
-            defaultStateHandler ?.let { list + it.holder { true } } ?: list
-        }
-    )
+    fun build() = fsmBuilder(states.toList(), defaultStateHandler)
 }
 
 fun <T : State> buildFSM(