zio · iravid · Sep 21, 2019 · Sep 21, 2019 · Sep 21, 2019 · Sep 21, 2019
diff --git a/streams-tests/jvm/src/test/scala/zio/stream/StreamSpec.scala b/streams-tests/jvm/src/test/scala/zio/stream/StreamSpec.scala
@@ -147,6 +147,7 @@ class StreamSpec(implicit ee: org.specs2.concurrent.ExecutionEnv) extends TestRu
   Stream.fromChunk          $fromChunk
   Stream.fromInputStream    $fromInputStream
   Stream.fromIterable       $fromIterable
+  Stream.fromIterator       $fromIterator
   Stream.fromQueue          $fromQueue
 
   Stream.groupBy
@@ -1228,6 +1229,10 @@ class StreamSpec(implicit ee: org.specs2.concurrent.ExecutionEnv) extends TestRu
     unsafeRunSync(Stream.fromIterable(l).runCollect) must_=== Success(l)
   }
 
+  private def fromIterator = prop { l: List[Int] =>
+    unsafeRunSync(Stream.fromIterator(UIO.effectTotal(l.iterator)).runCollect) must_=== Success(l)
+  }
+
   private def fromQueue = prop { c: Chunk[Int] =>
     val result = unsafeRunSync {
       for {

diff --git a/streams/shared/src/main/scala/zio/stream/Stream.scala b/streams/shared/src/main/scala/zio/stream/Stream.scala
@@ -169,6 +169,18 @@ object Stream extends ZStreamPlatformSpecific {
   final def fromIterable[A](as: Iterable[A]): Stream[Nothing, A] =
     ZStream.fromIterable(as)
 
+  /**
+   * See [[ZStream.fromIterator]]
+   */
+  final def fromIterator[E, A](iterator: IO[E, Iterator[A]]): Stream[E, A] =
+    ZStream.fromIterator(iterator)
+
+  /**
+   * See [[ZStream.fromIteratorManaged]]
+   */
+  final def fromIteratorManaged[E, A](iterator: Managed[E, Iterator[A]]): Stream[E, A] =
+    ZStream.fromIteratorManaged(iterator)
+
   /**
    * See [[ZStream.fromQueue]]
    */

diff --git a/streams/shared/src/main/scala/zio/stream/StreamEffect.scala b/streams/shared/src/main/scala/zio/stream/StreamEffect.scala
@@ -311,6 +311,15 @@ private[stream] object StreamEffect extends Serializable {
       }
     }
 
+  final def fromIterator[R, E, A](iterator: ZManaged[R, E, Iterator[A]]): StreamEffect[R, E, A] =
+    StreamEffect[R, E, A] {
+      iterator.flatMap { iterator =>
+        Managed.effectTotal { () =>
+          if (iterator.hasNext) iterator.next() else end
+        }
+      }
+    }
+
   final def unfold[S, A](s: S)(f0: S => Option[(A, S)]): StreamEffect[Any, Nothing, A] =
     StreamEffect[Any, Nothing, A] {
       Managed.effectTotal {

diff --git a/streams/shared/src/main/scala/zio/stream/ZStream.scala b/streams/shared/src/main/scala/zio/stream/ZStream.scala
@@ -2493,6 +2493,18 @@ object ZStream extends ZStreamPlatformSpecific {
   final def fromIterable[A](as: Iterable[A]): Stream[Nothing, A] =
     StreamEffect.fromIterable(as)
 
+  /**
+   * Creates a stream from an iterator
+   */
+  final def fromIterator[R, E, A](iterator: ZIO[R, E, Iterator[A]]): ZStream[R, E, A] =
+    fromIteratorManaged(iterator.toManaged_)
+
+  /**
+   * Creates a stream from an iterator
+   */
+  final def fromIteratorManaged[R, E, A](iterator: ZManaged[R, E, Iterator[A]]): ZStream[R, E, A] =
+    StreamEffect.fromIterator(iterator)
+
   /**
    * Creates a stream from a [[zio.ZQueue]] of values
    */