From 01ae67c212e95c1503402f4d4fdeb029caa3be18 Mon Sep 17 00:00:00 2001
From: Andrew Golovashevich <landgrafhomyak@gmail.com>
Date: Sun, 7 Sep 2025 00:42:19 +0300
Subject: [PATCH] Event loop and continuations interfaces

---
 build.gradle.kts                              |  8 ++++---
 .../multitasking_0/CancellationHandler.kt     |  5 ++++
 .../multitasking_0/Continuation.kt            | 24 +++++++++++++++++++
 .../multitasking_0/ContinuationHandler.kt     |  5 ++++
 .../multitasking_0/SingleThreadEventLoop.kt   | 11 +++++++++
 .../multitasking_0/TaskCancelledException.kt  | 10 ++++++++
 6 files changed, 60 insertions(+), 3 deletions(-)
 create mode 100644 src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/CancellationHandler.kt
 create mode 100644 src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/Continuation.kt
 create mode 100644 src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/ContinuationHandler.kt
 create mode 100644 src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/SingleThreadEventLoop.kt
 create mode 100644 src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/TaskCancelledException.kt

diff --git a/build.gradle.kts b/build.gradle.kts
index a93a69e..c7d5729 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -54,7 +54,11 @@ kotlin {
 	}
 
 	sourceSets {
-		val commonMain by getting
+		val commonMain by getting {
+			dependencies {
+				implementation("org.jetbrains.kotlin:kotlin-stdlib:${this@kotlin.coreLibrariesVersion}")
+			}
+		}
 		val commonTest by getting
 
 		val notJvmMain by creating { dependsOn(commonMain) }
@@ -88,8 +92,6 @@ kotlin {
 	}
 
 
-
-
 }
 
 publishing {
diff --git a/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/CancellationHandler.kt b/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/CancellationHandler.kt
new file mode 100644
index 0000000..7dafb21
--- /dev/null
+++ b/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/CancellationHandler.kt
@@ -0,0 +1,5 @@
+package ru.landgrafhomyak.multitasking_0
+
+public fun interface CancellationHandler {
+	public fun onCancellation(): Throwable
+}
\ No newline at end of file
diff --git a/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/Continuation.kt b/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/Continuation.kt
new file mode 100644
index 0000000..d99ab14
--- /dev/null
+++ b/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/Continuation.kt
@@ -0,0 +1,24 @@
+package ru.landgrafhomyak.multitasking_0
+
+/**
+ * Callback that resumes execution of a corresponding task [at suspension point][SingleThreadEventLoop.yield].
+ */
+public interface Continuation<T> {
+	/**
+	 * Resumes task with result that will be returned from [yield()][SingleThreadEventLoop.yield].
+	 */
+	public fun resumeWithSuccess(result: T)
+
+	/**
+	 * Resumes task with error that will be thrown from [yield()][SingleThreadEventLoop.yield].
+	 */
+	public fun resumeWithError(result: Throwable)
+
+
+	public interface Cancellable<T> : Continuation<T> {
+		/**
+		 * Set's callback called when task is canceled, but not earlier than [linkContinuation()][ContinuationHandler.linkContinuation] returns.
+		 */
+		public fun setCancellationHandler(handler: CancellationHandler)
+	}
+}
\ No newline at end of file
diff --git a/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/ContinuationHandler.kt b/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/ContinuationHandler.kt
new file mode 100644
index 0000000..e98bc1b
--- /dev/null
+++ b/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/ContinuationHandler.kt
@@ -0,0 +1,5 @@
+package ru.landgrafhomyak.multitasking_0
+
+public fun interface ContinuationHandler<R, C : Continuation<R>> {
+	public fun linkContinuation(continuation: C)
+}
\ No newline at end of file
diff --git a/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/SingleThreadEventLoop.kt b/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/SingleThreadEventLoop.kt
new file mode 100644
index 0000000..90149b1
--- /dev/null
+++ b/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/SingleThreadEventLoop.kt
@@ -0,0 +1,11 @@
+package ru.landgrafhomyak.multitasking_0
+
+public interface SingleThreadEventLoop {
+	public fun callAfter(delayMillis: Long, continuation: Continuation<Unit>)
+
+	public fun <R> yield(handler: ContinuationHandler<R, Continuation<R>>): R
+	public fun <R> yieldCancellable(handler: ContinuationHandler<R, Continuation.Cancellable<R>>): R
+
+	public fun runUntilSuspended()
+	public fun suspendEventLoop()
+}
\ No newline at end of file
diff --git a/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/TaskCancelledException.kt b/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/TaskCancelledException.kt
new file mode 100644
index 0000000..5317d76
--- /dev/null
+++ b/src/commonMain/kotlin/ru/landgrafhomyak/multitasking_0/TaskCancelledException.kt
@@ -0,0 +1,10 @@
+package ru.landgrafhomyak.multitasking_0
+
+import kotlin.RuntimeException
+
+public class TaskCancelledException : RuntimeException {
+	public constructor() : super()
+	public constructor(message: String?) : super(message)
+	public constructor(message: String?, cause: Throwable?) : super(message, cause)
+	public constructor(cause: Throwable?) : super(cause)
+}
\ No newline at end of file