1 files changed, 48 insertions, 0 deletions
diff --git a/sbt-plugin/src/main/scala/scala/scalajs/sbtplugin/ScalaJSCrossVersion.scala b/sbt-plugin/src/main/scala/scala/scalajs/sbtplugin/ScalaJSCrossVersion.scala
new file mode 100644
index 0000000..d813622
--- /dev/null
+++ b/sbt-plugin/src/main/scala/scala/scalajs/sbtplugin/ScalaJSCrossVersion.scala
@@ -0,0 +1,48 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___      __ ____  Scala.js sbt plugin        **
+**    / __/ __// _ | / /  / _ | __ / // __/  (c) 2013, LAMP/EPFL        **
+**  __\ \/ /__/ __ |/ /__/ __ |/_// /_\ \    http://scala-js.org/       **
+** /____/\___/_/ |_/____/_/ | |__/ /____/                               **
+**                          |/____/                                     **
+\*                                                                      */
+
+
+package scala.scalajs.sbtplugin
+
+import sbt._
+
+import scala.scalajs.ir.ScalaJSVersions
+
+object ScalaJSCrossVersion {
+  private val scalaJSVersionUnmapped: String => String =
+    _ => s"sjs$currentBinaryVersion"
+
+  private val scalaJSVersionMap: String => String =
+    version => s"sjs${currentBinaryVersion}_$version"
+
+  private final val ReleaseVersion =
+    raw"""(\d+)\.(\d+)\.(\d+)""".r
+  private final val MinorSnapshotVersion =
+    raw"""(\d+)\.(\d+)\.([1-9]\d*)-SNAPSHOT""".r
+
+  val currentBinaryVersion = binaryScalaJSVersion(ScalaJSVersions.current)
+
+  def binaryScalaJSVersion(full: String): String = full match {
+    case ReleaseVersion(major, minor, release) => s"$major.$minor"
+    case MinorSnapshotVersion(major, minor, _) => s"$major.$minor"
+    case _                                     => full
+  }
+
+  def scalaJSMapped(cross: CrossVersion): CrossVersion = cross match {
+    case CrossVersion.Disabled =>
+      CrossVersion.binaryMapped(scalaJSVersionUnmapped)
+    case cross: CrossVersion.Binary =>
+      CrossVersion.binaryMapped(cross.remapVersion andThen scalaJSVersionMap)
+    case cross: CrossVersion.Full =>
+      CrossVersion.fullMapped(cross.remapVersion andThen scalaJSVersionMap)
+  }
+
+  def binary: CrossVersion = scalaJSMapped(CrossVersion.binary)
+
+  def full: CrossVersion = scalaJSMapped(CrossVersion.full)
+}