1 files changed, 119 insertions, 0 deletions
diff --git a/contrib/twirllib/src/mill/twirllib/TwirlWorker.scala b/contrib/twirllib/src/mill/twirllib/TwirlWorker.scala
new file mode 100644
index 00000000..f351ff2f
--- /dev/null
+++ b/contrib/twirllib/src/mill/twirllib/TwirlWorker.scala
@@ -0,0 +1,119 @@
+package mill
+package twirllib
+
+import java.io.File
+import java.lang.reflect.Method
+import java.net.URLClassLoader
+
+import ammonite.ops.{Path, ls}
+import mill.eval.PathRef
+import mill.scalalib.CompilationResult
+
+import scala.io.Codec
+
+class TwirlWorker {
+
+  private var twirlInstanceCache = Option.empty[(Long, TwirlWorkerApi)]
+
+  private def twirl(twirlClasspath: Agg[Path]) = {
+    val classloaderSig = twirlClasspath.map(p => p.toString().hashCode + p.mtime.toMillis).sum
+    twirlInstanceCache match {
+      case Some((sig, instance)) if sig == classloaderSig => instance
+      case _ =>
+        val cl = new URLClassLoader(twirlClasspath.map(_.toIO.toURI.toURL).toArray)
+        val twirlCompilerClass = cl.loadClass("play.twirl.compiler.TwirlCompiler")
+        val compileMethod = twirlCompilerClass.getMethod("compile",
+          classOf[java.io.File],
+          classOf[java.io.File],
+          classOf[java.io.File],
+          classOf[java.lang.String],
+          cl.loadClass("scala.collection.Seq"),
+          cl.loadClass("scala.collection.Seq"),
+          cl.loadClass("scala.io.Codec"),
+          classOf[Boolean])
+
+        val defaultAdditionalImportsMethod = twirlCompilerClass.getMethod("compile$default$5")
+        val defaultConstructorAnnotationsMethod = twirlCompilerClass.getMethod("compile$default$6")
+        val defaultCodecMethod = twirlCompilerClass.getMethod("compile$default$7")
+        val defaultFlagMethod = twirlCompilerClass.getMethod("compile$default$8")
+
+        val instance = new TwirlWorkerApi {
+          override def compileTwirl(source: File,
+                                    sourceDirectory: File,
+                                    generatedDirectory: File,
+                                    formatterType: String,
+                                    additionalImports: Seq[String],
+                                    constructorAnnotations: Seq[String],
+                                    codec: Codec,
+                                    inclusiveDot: Boolean) {
+            val o = compileMethod.invoke(null, source,
+              sourceDirectory,
+              generatedDirectory,
+              formatterType,
+              defaultAdditionalImportsMethod.invoke(null),
+              defaultConstructorAnnotationsMethod.invoke(null),
+              defaultCodecMethod.invoke(null),
+              defaultFlagMethod.invoke(null))
+          }
+        }
+        twirlInstanceCache = Some((classloaderSig, instance))
+        instance
+    }
+  }
+
+  def compile(twirlClasspath: Agg[Path],
+              sourceDirectories: Seq[Path],
+              dest: Path,
+              additionalImports: Seq[String],
+              constructorAnnotations: Seq[String],
+              codec: Codec,
+              inclusiveDot: Boolean)
+             (implicit ctx: mill.util.Ctx): mill.eval.Result[CompilationResult] = {
+    val compiler = twirl(twirlClasspath)
+
+    def compileTwirlDir(inputDir: Path) {
+      ls.rec(inputDir).filter(_.name.matches(".*.scala.(html|xml|js|txt)"))
+        .foreach { template =>
+          val extFormat = twirlExtensionFormat(template.name)
+          compiler.compileTwirl(template.toIO,
+            inputDir.toIO,
+            dest.toIO,
+            s"play.twirl.api.$extFormat",
+            additionalImports,
+            constructorAnnotations,
+            codec,
+            inclusiveDot
+          )
+        }
+    }
+
+    sourceDirectories.foreach(compileTwirlDir)
+
+    val zincFile = ctx.dest / 'zinc
+    val classesDir = ctx.dest / 'html
+
+    mill.eval.Result.Success(CompilationResult(zincFile, PathRef(classesDir)))
+  }
+
+  private def twirlExtensionFormat(name: String) =
+    if (name.endsWith("html")) "HtmlFormat"
+    else if (name.endsWith("xml")) "XmlFormat"
+    else if (name.endsWith("js")) "JavaScriptFormat"
+    else "TxtFormat"
+}
+
+trait TwirlWorkerApi {
+  def compileTwirl(source: File,
+                   sourceDirectory: File,
+                   generatedDirectory: File,
+                   formatterType: String,
+                   additionalImports: Seq[String],
+                   constructorAnnotations: Seq[String],
+                   codec: Codec,
+                   inclusiveDot: Boolean)
+}
+
+object TwirlWorkerApi {
+
+  def twirlWorker = new TwirlWorker()
+}