Create a Chunk from an IterableOnce

core/shared/src/main/scala-2.12/fs2/ChunkPlatform.scala

@@ -24,10 +24,7 @@ package fs2
 import scala.collection.mutable.{ArrayBuilder, WrappedArray}
 import scala.reflect.ClassTag
 
-private[fs2] trait ChunkPlatform[+O] { self: Chunk[O] =>
-  protected def makeArrayBuilder[A](implicit ct: ClassTag[A]): ArrayBuilder[A] =
-    ArrayBuilder.make()(ct)
-}
+private[fs2] trait ChunkPlatform[+O] { self: Chunk[O] => }
 
 private[fs2] trait ChunkCompanionPlatform { self: Chunk.type =>
 
@@ -37,6 +34,9 @@ private[fs2] trait ChunkCompanionPlatform { self: Chunk.type =>
       case _                  => None
     }
 
+  private[fs2] def makeArrayBuilder[A](implicit ct: ClassTag[A]): ArrayBuilder[A] =
+    ArrayBuilder.make()(ct)
+
   /** Creates a chunk backed by a `WrappedArray`
     */
   def wrappedArray[O](wrappedArray: WrappedArray[O]): Chunk[O] = {

core/shared/src/main/scala-2.13/fs2/ChunkPlatform.scala

@@ -28,9 +28,6 @@ import scala.reflect.ClassTag
 
 private[fs2] trait ChunkPlatform[+O] { self: Chunk[O] =>
 
-  protected def makeArrayBuilder[A](implicit ct: ClassTag[A]): ArrayBuilder[A] =
-    ArrayBuilder.make(ct)
-
   def toArraySeq[O2 >: O: ClassTag]: ArraySeq[O2] = {
     val array: Array[O2] = new Array[O2](size)
     copyToArray(array)
@@ -57,10 +54,17 @@ private[fs2] trait ChunkCompanionPlatform { self: Chunk.type =>
       case _                        => None
     }
 
+  private[fs2] def makeArrayBuilder[A](implicit ct: ClassTag[A]): ArrayBuilder[A] =
+    ArrayBuilder.make(ct)
+
   /** Creates a chunk backed by an immutable `ArraySeq`.
     */
   def arraySeq[O](arraySeq: immutable.ArraySeq[O]): Chunk[O] = {
     val arr = arraySeq.unsafeArray.asInstanceOf[Array[O]]
     array(arr)(ClassTag[O](arr.getClass.getComponentType))
   }
+
+  /** Creates a chunk from a `scala.collection.IterableOnce`. */
+  def iterableOnce[O](i: collection.IterableOnce[O]): Chunk[O] =
+    iterator(i.iterator)
 }

core/shared/src/main/scala-3/fs2/ChunkPlatform.scala

@@ -28,9 +28,6 @@ import scala.reflect.ClassTag
 
 private[fs2] trait ChunkPlatform[+O] { self: Chunk[O] =>
 
-  protected def makeArrayBuilder[A](implicit ct: ClassTag[A]): ArrayBuilder[A] =
-    ArrayBuilder.make(ct)
-
   def toArraySeq[O2 >: O: ClassTag]: ArraySeq[O2] = {
     val array: Array[O2] = new Array[O2](size)
     copyToArray(array)
@@ -66,6 +63,9 @@ private[fs2] trait ChunkCompanionPlatform { self: Chunk.type =>
       case _                        => None
     }
 
+  private[fs2] def makeArrayBuilder[A](implicit ct: ClassTag[A]): ArrayBuilder[A] =
+    ArrayBuilder.make(ct)
+
   /** Creates a chunk backed by an immutable `ArraySeq`.
     */
   def arraySeq[O](arraySeq: immutable.ArraySeq[O]): Chunk[O] = {
@@ -119,4 +119,8 @@ private[fs2] trait ChunkCompanionPlatform { self: Chunk.type =>
       if (offset == 0 && length == values.length) values
       else super.toIArray[O2]
   }
+
+  /** Creates a chunk from a `scala.collection.IterableOnce`. */
+  def iterableOnce[O](i: collection.IterableOnce[O]): Chunk[O] =
+    iterator(i.iterator)
 }

core/shared/src/main/scala/fs2/Chunk.scala

@@ -112,7 +112,7 @@ abstract class Chunk[+O] extends Serializable with ChunkPlatform[O] with ChunkRu
 
   /** Returns a chunk that has only the elements that satisfy the supplied predicate. */
   def filter(p: O => Boolean): Chunk[O] = {
-    val b = makeArrayBuilder(thisClassTag)
+    val b = Chunk.makeArrayBuilder(thisClassTag)
     b.sizeHint(size)
     foreach(e => if (p(e)) b += e)
     Chunk.array(b.result()).asInstanceOf[Chunk[O]]
@@ -209,7 +209,7 @@ abstract class Chunk[+O] extends Serializable with ChunkPlatform[O] with ChunkRu
 
   /** Maps the supplied function over each element and returns a chunk of just the defined results. */
   def mapFilter[O2](f: O => Option[O2]): Chunk[O2] = {
-    val b = makeArrayBuilder[Any]
+    val b = Chunk.makeArrayBuilder[Any]
     b.sizeHint(size)
     foreach { o =>
       val o2 = f(o)
@@ -324,7 +324,7 @@ abstract class Chunk[+O] extends Serializable with ChunkPlatform[O] with ChunkRu
     */
   def toIndexedChunk: Chunk[O] = this match {
     case _: Chunk.Queue[_] =>
-      val b = makeArrayBuilder[Any]
+      val b = Chunk.makeArrayBuilder[Any]
       b.sizeHint(size)
       foreach(o => b += o)
       Chunk.array(b.result()).asInstanceOf[Chunk[O]]
@@ -599,18 +599,22 @@ object Chunk
       case ix: GIndexedSeq[O] => indexedSeq(ix)
       case _ =>
         if (i.isEmpty) empty
-        else {
-          val itr = i.iterator
-          val head = itr.next()
-          if (itr.hasNext) {
-            val bldr = collection.mutable.Buffer.newBuilder[O]
-            bldr += head
-            bldr ++= itr
-            buffer(bldr.result())
-          } else singleton(head)
-        }
+        else iterator(i.iterator)
     })
 
+  /** Creates a chunk from a `scala.collection.Iterator`. */
+  def iterator[O](itr: collection.Iterator[O]): Chunk[O] =
+    if (itr.isEmpty) empty
+    else {
+      val head = itr.next()
+      if (itr.hasNext) {
+        val bldr = Chunk.makeArrayBuilder[Any]
+        bldr += head
+        bldr ++= itr
+        array(bldr.result()).asInstanceOf[Chunk[O]]
+      } else singleton(head)
+    }
+
   /** Creates a chunk backed by a mutable `ArraySeq`.
     */
   def arraySeq[O](arraySeq: mutable.ArraySeq[O]): Chunk[O] = {
@@ -621,16 +625,7 @@ object Chunk
   /** Creates a chunk backed by a `Chain`. */
   def chain[O](c: Chain[O]): Chunk[O] =
     if (c.isEmpty) empty
-    else {
-      val itr = c.iterator
-      val head = itr.next()
-      if (itr.hasNext) {
-        val bldr = collection.mutable.Buffer.newBuilder[O]
-        bldr += head
-        bldr ++= itr
-        buffer(bldr.result())
-      } else singleton(head)
-    }
+    else iterator(c.iterator)
 
   /** Creates a chunk backed by a mutable buffer. The underlying buffer must not be modified after
     * it is passed to this function.