1 files changed, 67 insertions, 0 deletions
diff --git a/sbt-plugin/src/main/scala/scala/scalajs/sbtplugin/env/VirtualFileMaterializer.scala b/sbt-plugin/src/main/scala/scala/scalajs/sbtplugin/env/VirtualFileMaterializer.scala
new file mode 100644
index 0000000..fca1c47
--- /dev/null
+++ b/sbt-plugin/src/main/scala/scala/scalajs/sbtplugin/env/VirtualFileMaterializer.scala
@@ -0,0 +1,67 @@
+package scala.scalajs.sbtplugin.env
+
+import scala.scalajs.tools.io.{IO => _, _}
+
+import sbt.IO
+
+import java.io.File
+
+/** A helper class to temporarily store virtual files to the filesystem.
+ *  
+ *  Can be used with tools that require real files.
+ *  @param singleDir if true, forces files to be copied into
+ *      [[cacheDir]]. Useful to setup include directories for
+ *      example.
+ */
+final class VirtualFileMaterializer(singleDir: Boolean = false) {
+
+  val cacheDir = {
+    val dir = IO.createTemporaryDirectory
+    dir.deleteOnExit()
+    dir
+  }
+
+  /** Create a target file to write/copy to. Will also call
+   *  deleteOnExit on the file.
+   */
+  private def trgFile(name: String): File = {
+    val f = new File(cacheDir, name)
+    f.deleteOnExit()
+    f
+  }
+
+  private def materializeFileVF(vf: FileVirtualFile): File = {
+    if (!singleDir) vf.file
+    else {
+      val trg = trgFile(vf.name)
+      IO.copyFile(vf.file, trg)
+      trg
+    }
+  }
+
+  def materialize(vf: VirtualTextFile): File = vf match {
+    case vf: FileVirtualFile => materializeFileVF(vf)
+    case _ =>
+      val trg = trgFile(vf.name)
+      IO.write(trg, vf.content)
+      trg
+  }
+
+  def materialize(vf: VirtualBinaryFile): File = vf match {
+    case vf: FileVirtualFile => materializeFileVF(vf)
+    case _ =>
+      val trg = trgFile(vf.name)
+      IO.write(trg, vf.content)
+      trg
+  }
+
+  /** Removes the cache directory. Any operation on this
+   *  VirtualFileMaterializer is invalid after [[close]] has been
+   *  called.
+   */
+  def close(): Unit = {
+    cacheDir.listFiles().foreach(_.delete)
+    cacheDir.delete()
+  }
+
+}