2 files changed, 65 insertions, 1 deletions
diff --git a/stage2/BasicBuild.scala b/stage2/BasicBuild.scala
index 42384db..410d68f 100644
--- a/stage2/BasicBuild.scala
+++ b/stage2/BasicBuild.scala
@@ -136,6 +136,16 @@ trait BaseBuild extends DependencyImplementation with BuildInterface with Trigge
   def runClass: String = "Main"
   def run: ExitCode = lib.runMainIfFound( runClass, context.args, classLoader(context.classLoaderCache) )
 
+  def clean = {
+    lib.clean(
+      target,
+      context.args.contains("force"),
+      context.args.contains("dry-run"),
+      context.args.contains("list"),
+      context.args.contains("help")
+    )
+  }
+
   def test: Option[ExitCode] = 
     Some(new lib.ReflectBuild(
       DirectoryDependency(projectDirectory++"/test").build
diff --git a/stage2/Lib.scala b/stage2/Lib.scala
index 118c9a4..5b175c1 100644
--- a/stage2/Lib.scala
+++ b/stage2/Lib.scala
@@ -4,7 +4,7 @@ import java.io._
 import java.net._
 import java.lang.reflect.InvocationTargetException
 import java.nio.file.{Path =>_,_}
-import java.nio.file.Files.readAllBytes
+import java.nio.file.Files.{readAllBytes, deleteIfExists, delete}
 import java.security.MessageDigest
 import java.util.jar._
 import java.lang.reflect.Method
@@ -199,6 +199,60 @@ final class Lib(logger: Logger) extends Stage1Lib(logger) with Scaffold{
     }
   }
 
+  def clean(target: File, force: Boolean, dryRun: Boolean, list: Boolean, help: Boolean): ExitCode = {
+    def depthFirstFileStream(file: File): Vector[File] = {
+      (
+        if (file.isDirectory) {
+          file.listFiles.toVector.flatMap(depthFirstFileStream(_))
+        } else Vector()
+      ) :+ file
+    }
+    lazy val files = depthFirstFileStream( target )
+
+    if( help ){
+      System.err.println( s"""
+  list      lists files to be delete
+  force     does not ask for confirmation
+  dry-run   does not actually delete files
+""" )
+      ExitCode.Success
+    } else if (!target.exists){
+      System.err.println( "Nothing to clean. Does not exist: " ++ target.string )
+      ExitCode.Success
+    } else if( list ){
+      files.map(_.string).foreach( println )
+      ExitCode.Success
+    } else {
+      val performDelete = (
+        force || {
+          val console = Option(System.console).getOrElse(
+            throw new Exception("Can't access Console. Try running `cbt direct clean` or `cbt clean list` or `cbt clean force`.")
+          )
+          System.err.println("Files to be deleted:\n\n")
+          files.foreach( System.err.println )
+          System.err.println("")
+          System.err.print("To delete the above files type 'delete': ")
+          console.readLine() == "delete"
+        }
+      )
+
+      if( !performDelete ) {
+        System.err.println( "Ok, not cleaning." )
+        ExitCode.Failure
+      } else {
+        // use same Vector[File] that was displayed earlier as a safety measure
+        files.foreach{ file => 
+          System.err.println( red("Deleting") ++ " " ++ file.string )
+          if(!dryRun){
+            delete( file.toPath )
+          }
+        }
+        System.err.println( "Done." )
+        ExitCode.Success
+      }
+    }
+  }
+
   // file system helpers
   def basename(path: File): String = path.toString.stripSuffix("/").split("/").last
   def dirname(path: File): File = new File(realpath(path).string.stripSuffix("/").split("/").dropRight(1).mkString("/"))