First pass at an `assembly` task now works, rudimentary but enough to be used metacircularly

2 files changed, 57 insertions, 4 deletions

diff --git a/core/src/main/scala/mill/Main.scala b/core/src/main/scala/mill/Main.scala
index 9e7a9d11..9a3ade04 100644
--- a/core/src/main/scala/mill/Main.scala
+++ b/core/src/main/scala/mill/Main.scala
@@ -38,7 +38,7 @@ object Main {
             case _ => // do nothing
           }
 
-        case None => println("Unknown selector: " + selector)
+        case None => println("Unknown selector: " + selector.mkString("."))
       }
     }
   }
diff --git a/core/src/main/scala/mill/modules/Jvm.scala b/core/src/main/scala/mill/modules/Jvm.scala
index f18e2d96..63f335f5 100644
--- a/core/src/main/scala/mill/modules/Jvm.scala
+++ b/core/src/main/scala/mill/modules/Jvm.scala
@@ -1,13 +1,15 @@
 package mill.modules
 
 import java.io.FileOutputStream
-import java.util.jar.{JarEntry, JarOutputStream}
+import java.util.jar.{JarEntry, JarFile, JarInputStream, JarOutputStream}
 
 import ammonite.ops._
 import mill.define.Task
 import mill.eval.PathRef
 import mill.util.Args
 
+import scala.collection.mutable
+
 
 object Jvm {
 
@@ -43,8 +45,8 @@ object Jvm {
         for{
           p <- inputPaths
           (file, mapping) <-
-          if (p.isFile) Iterator(p -> empty/p.last)
-          else ls.rec(p).filter(_.isFile).map(sub => sub -> sub.relativeTo(p))
+            if (p.isFile) Iterator(p -> empty/p.last)
+            else ls.rec(p).filter(_.isFile).map(sub => sub -> sub.relativeTo(p))
         } {
           val entry = new JarEntry(mapping.toString)
           entry.setTime(file.mtime.toMillis)
@@ -59,6 +61,57 @@ object Jvm {
       Some(outputPath)
     }
   }
+
+
+  def createAssembly(outputPath: Path,
+                     inputPaths: Seq[Path],
+                     mainClass: Option[String] = None): Option[Path] = {
+    rm(outputPath)
+
+    if(inputPaths.isEmpty) None
+    else {
+      mkdir(outputPath/up)
+
+      val jar = new JarOutputStream(
+        new FileOutputStream(outputPath.toIO),
+        createManifest(mainClass)
+      )
+
+      val seen = mutable.Set("META-INF/MANIFEST.MF")
+      try{
+        assert(inputPaths.forall(exists(_)))
+        for{
+          p <- inputPaths
+
+          (file, mapping) <-
+            if (p.isFile) {
+              val jf = new JarFile(p.toIO)
+              import collection.JavaConverters._
+              for(entry <- jf.entries().asScala if !entry.isDirectory) yield {
+                read.bytes(jf.getInputStream(entry)) -> entry.getName
+              }
+            }
+            else {
+              ls.rec(p).iterator
+                .filter(_.isFile)
+                .map(sub => read.bytes(sub) -> sub.relativeTo(p).toString)
+            }
+          if !seen(mapping)
+        } {
+          seen.add(mapping)
+          val entry = new JarEntry(mapping.toString)
+          jar.putNextEntry(entry)
+          jar.write(file)
+          jar.closeEntry()
+        }
+      } finally {
+        jar.close()
+      }
+
+      Some(outputPath)
+    }
+  }
+
   def jarUp(roots: Task[PathRef]*) = new Task[PathRef]{
 
     val inputs = roots