updates in coroutines

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 ## 0.4.19
 
+* `Coroutines`:
+    * New extension `Iterable<Deferred>#awaitFirstWithDeferred` has been added to identify which of `Deferred`s was
+      normally completed
+    * New extensions `Iterable<Deferred<T>>#invokeOnFirst` and `Iterable<DeferredAction<*, O>>.invokeFirstOf` have been
+    added
+
 ## 0.4.18
 
 * `Coroutines`:

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

@@ -3,15 +3,15 @@ package dev.inmo.micro_utils.coroutines
 import kotlinx.coroutines.*
 import kotlin.coroutines.*
 
-suspend fun <T> Iterable<Deferred<T>>.awaitFirst(
+suspend fun <T> Iterable<Deferred<T>>.awaitFirstWithDeferred(
     scope: CoroutineScope,
     cancelOnResult: Boolean = true
-): T = suspendCoroutine<T> { continuation ->
+): Pair<Deferred<T>, T> = suspendCoroutine<Pair<Deferred<T>, T>> { continuation ->
     scope.launch(SupervisorJob()) {
         val scope = this
         forEach {
             scope.launch {
-                continuation.resume(it.await())
+                continuation.resume(it to it.await())
                 scope.cancel()
             }
         }
@@ -27,6 +27,11 @@ suspend fun <T> Iterable<Deferred<T>>.awaitFirst(
         }
     }
 }
+
+suspend fun <T> Iterable<Deferred<T>>.awaitFirst(
+    scope: CoroutineScope,
+    cancelOnResult: Boolean = true
+): T = awaitFirstWithDeferred(scope, cancelOnResult).second
 suspend fun <T> Iterable<Deferred<T>>.awaitFirst(
     cancelOthers: Boolean = true
 ): T = awaitFirst(CoroutineScope(coroutineContext), cancelOthers)

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

@@ -0,0 +1,40 @@
+package dev.inmo.micro_utils.coroutines
+
+import kotlinx.coroutines.*
+
+class DeferredAction<T, O>(
+    val deferred: Deferred<T>,
+    val callback: suspend (T) -> O
+) {
+    suspend operator fun invoke() = callback(deferred.await())
+}
+
+fun <T, O> Deferred<T>.buildAction(callback: suspend (T) -> O) = DeferredAction(this, callback)
+
+suspend fun <O> Iterable<DeferredAction<*, O>>.invokeFirstOf(
+    scope: CoroutineScope,
+    cancelOnResult: Boolean = true
+): O {
+    return map { it.deferred }.awaitFirstWithDeferred(scope, cancelOnResult).let { result ->
+        first { it.deferred == result.first }.invoke()
+    }
+}
+
+suspend fun <O> invokeFirstOf(
+    scope: CoroutineScope,
+    vararg variants: DeferredAction<*, O>,
+    cancelOnResult: Boolean = true
+): O = variants.toList().invokeFirstOf(scope, cancelOnResult)
+
+suspend fun <T, O> Iterable<Deferred<T>>.invokeOnFirst(
+    scope: CoroutineScope,
+    cancelOnResult: Boolean = true,
+    callback: suspend (T) -> O
+): O = map { it.buildAction(callback) }.invokeFirstOf(scope, cancelOnResult)
+
+suspend fun <T, O> invokeOnFirst(
+    scope: CoroutineScope,
+    vararg variants: Deferred<T>,
+    cancelOnResult: Boolean = true,
+    callback: suspend (T) -> O
+): O = variants.toList().invokeOnFirst(scope, cancelOnResult, callback)

coroutines/src/jvmTest/kotlin/dev/inmo/micro_utils/coroutines/DoWithFirstTests.kt

@@ -0,0 +1,27 @@
+package dev.inmo.micro_utils.coroutines
+
+import dev.inmo.micro_utils.coroutines.asDeferred
+import dev.inmo.micro_utils.coroutines.launchSynchronously
+import kotlinx.coroutines.*
+import kotlin.test.*
+
+class DoWithFirstTests {
+    @Test
+    fun testHandleOneOf() {
+        val scope = CoroutineScope(Dispatchers.Default)
+        val happenedDeferreds = mutableListOf<Int>()
+        val deferredWhichMustHappen = (-1).asDeferred
+        scope.launchSynchronously {
+            scope.launch {
+                ((0 until 100).map {
+                    DeferredAction(
+                        scope.async { delay(10000); it },
+                        happenedDeferreds::add
+                    )
+                } + DeferredAction(deferredWhichMustHappen, happenedDeferreds::add)).invokeFirstOf(scope)
+            }.join()
+        }
+        assertEquals(1, happenedDeferreds.size)
+        assertEquals(scope.launchSynchronously { deferredWhichMustHappen.await() }, happenedDeferreds.first())
+    }
+}