IJPL-163530 Improve service instance container to allow multiple instances for different classloaders

GitOrigin-RevId: c29c9396fe50abbafa4e499ce7d6cc41209e4148

platform/platform-api/api-dump-experimental.txt

@@ -122,6 +122,15 @@ f:com.intellij.ide.dnd.SmoothAutoScroller
 *:com.intellij.ide.environment.EnvironmentService
 - a:getEnvironmentValue(com.intellij.ide.environment.EnvironmentKey,java.lang.String,kotlin.coroutines.Continuation):java.lang.Object
 - a:getEnvironmentValue(com.intellij.ide.environment.EnvironmentKey,kotlin.coroutines.Continuation):java.lang.Object
+*f:com.intellij.ide.ui.LafFlowService
+- *sf:Companion:com.intellij.ide.ui.LafFlowService$Companion
+- <init>(kotlinx.coroutines.CoroutineScope):V
+- f:customLafFlowState(java.lang.Object,kotlinx.coroutines.flow.SharingStarted,kotlin.jvm.functions.Function1):kotlinx.coroutines.flow.StateFlow
+- bs:customLafFlowState$default(com.intellij.ide.ui.LafFlowService,java.lang.Object,kotlinx.coroutines.flow.SharingStarted,kotlin.jvm.functions.Function1,I,java.lang.Object):kotlinx.coroutines.flow.StateFlow
+- sf:getInstance():com.intellij.ide.ui.LafFlowService
+- f:getLafChangedFlow():kotlinx.coroutines.flow.SharedFlow
+*f:com.intellij.ide.ui.LafFlowService$Companion
+- f:getInstance():com.intellij.ide.ui.LafFlowService
 a:com.intellij.ide.ui.LafManager
 - *a:getInstalledThemes():kotlin.sequences.Sequence
 *:com.intellij.ide.ui.PopupLocator

platform/platform-api/src/com/intellij/ide/ui/LafFlowService.kt

@@ -0,0 +1,52 @@
+// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.ide.ui
+
+import com.intellij.openapi.application.Application
+import com.intellij.openapi.application.ApplicationManager
+import com.intellij.openapi.components.Service
+import com.intellij.openapi.components.service
+import com.intellij.util.messages.MessageBus
+import com.intellij.util.messages.SimpleMessageBusConnection
+import com.intellij.util.messages.Topic
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.channels.ProducerScope
+import kotlinx.coroutines.channels.awaitClose
+import kotlinx.coroutines.flow.*
+import org.jetbrains.annotations.ApiStatus
+
+@ApiStatus.Experimental
+@Service(Service.Level.APP)
+class LafFlowService(
+  private val scope: CoroutineScope,
+) {
+  private val lafEventFlow = ApplicationManager.getApplication().lookAndFeelFlow(scope)
+
+  @Suppress("MemberVisibilityCanBePrivate")
+  val lafChangedFlow: SharedFlow<Unit> = lafEventFlow.onStart { emit(Unit) }.shareIn(scope, SharingStarted.Eagerly, replay = 1)
+
+  fun <T> customLafFlowState(
+    default: T,
+    sharingStarted: SharingStarted = SharingStarted.Eagerly,
+    mapper: (SharedFlow<Unit>) -> Flow<T>,
+  ): StateFlow<T> {
+    return mapper(lafChangedFlow).stateIn(scope, sharingStarted, default)
+  }
+
+  companion object {
+    @JvmStatic
+    fun getInstance(): LafFlowService = service<LafFlowService>()
+  }
+}
+
+private fun Application.lookAndFeelFlow(scope: CoroutineScope): Flow<Unit> =
+  messageBus.flow(LafManagerListener.TOPIC, scope) { LafManagerListener { trySend(Unit) } }
+
+private fun <L : Any, K> MessageBus.flow(
+  topic: Topic<L>,
+  parentScope: CoroutineScope,
+  listener: ProducerScope<K>.() -> L,
+): Flow<K> = callbackFlow {
+  val connection: SimpleMessageBusConnection = connect(parentScope)
+  connection.subscribe(topic, listener())
+  awaitClose { connection.disconnect() }
+}