CompletableDeferred constructor with parent Job added

Author: elizarov

core/kotlinx-coroutines-core/src/main/kotlin/kotlinx/coroutines/experimental/CompletableDeferred.kt

@@ -71,19 +71,30 @@ public interface CompletableDeferred<T> : Deferred<T> {
 
 /**
  * Creates a [CompletableDeferred] in an _active_ state.
+ * It is optionally a child of a [parent] job.
  */
-public fun <T> CompletableDeferred(): CompletableDeferred<T> = CompletableDeferredImpl()
+@Suppress("FunctionName")
+public fun <T> CompletableDeferred(parent: Job? = null): CompletableDeferred<T> = CompletableDeferredImpl(parent)
+
+/** @suppress **Deprecated:** Binary compatibility only */
+@Deprecated(message = "Binary compatibility only", level = DeprecationLevel.HIDDEN)
+@Suppress("FunctionName")
+public fun <T> CompletableDeferred(): CompletableDeferred<T> = CompletableDeferredImpl(null)
 
 /**
  * Creates an already _completed_ [CompletableDeferred] with a given [value].
  */
-public fun <T> CompletableDeferred(value: T): CompletableDeferred<T> = CompletableDeferredImpl<T>().apply { complete(value) }
+@Suppress("FunctionName")
+public fun <T> CompletableDeferred(value: T): CompletableDeferred<T> = CompletableDeferredImpl<T>(null).apply { complete(value) }
 
 /**
  * Concrete implementation of [CompletableDeferred].
  */
 @Suppress("UNCHECKED_CAST")
-private class CompletableDeferredImpl<T> : JobSupport(true), CompletableDeferred<T> {
+private class CompletableDeferredImpl<T>(
+    parent: Job?
+) : JobSupport(true), CompletableDeferred<T> {
+    init { initParentJob(parent) }
     override fun getCompleted(): T = getCompletedInternal() as T
     suspend override fun await(): T = awaitInternal() as T
     override val onAwait: SelectClause1<T>

core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/CompletableDeferredTest.kt

@@ -27,6 +27,10 @@ class CompletableDeferredTest : TestBase() {
     @Test
     fun testFresh() {
         val c = CompletableDeferred<String>()
+        checkFresh(c)
+    }
+
+    private fun checkFresh(c: CompletableDeferred<String>) {
         assertThat(c.isActive, IsEqual(true))
         assertThat(c.isCancelled, IsEqual(false))
         assertThat(c.isCompleted, IsEqual(false))
@@ -112,6 +116,50 @@ class CompletableDeferredTest : TestBase() {
         assertThat(c.getCompletionExceptionOrNull(), IsInstanceOf(TestException::class.java))
     }
 
+    @Test
+    fun testParentCancelsChild() {
+        val parent = Job()
+        val c = CompletableDeferred<String>(parent)
+        checkFresh(c)
+        parent.cancel()
+        assertThat(parent.isActive, IsEqual(false))
+        assertThat(parent.isCancelled, IsEqual(true))
+        checkCancel(c)
+    }
+
+    @Test
+    fun testParentActiveOnChildCompletion() {
+        val parent = Job()
+        val c = CompletableDeferred<String>(parent)
+        checkFresh(c)
+        assertThat(parent.isActive, IsEqual(true))
+        assertThat(c.complete("OK"), IsEqual(true))
+        checkCompleteOk(c)
+        assertThat(parent.isActive, IsEqual(true))
+    }
+
+    @Test
+    fun testParentActiveOnChildException() {
+        val parent = Job()
+        val c = CompletableDeferred<String>(parent)
+        checkFresh(c)
+        assertThat(parent.isActive, IsEqual(true))
+        assertThat(c.completeExceptionally(TestException()), IsEqual(true))
+        checkCompleteTestException(c)
+        assertThat(parent.isActive, IsEqual(true))
+    }
+
+    @Test
+    fun testParentActiveOnChildCancellation() {
+        val parent = Job()
+        val c = CompletableDeferred<String>(parent)
+        checkFresh(c)
+        assertThat(parent.isActive, IsEqual(true))
+        assertThat(c.cancel(), IsEqual(true))
+        checkCancel(c)
+        assertThat(parent.isActive, IsEqual(true))
+    }
+
     @Test
     fun testAwait() = runBlocking {
         expect(1)