Split out `upstreamAssembly` from `assembly`

Also re-write `Jvm.createAssembly` to allow incremental assembly construction. This should allow much faster assembly creation in the common case where upstream dependencies do not change

3 files changed, 37 insertions, 19 deletions

diff --git a/core/src/mill/eval/PathRef.scala b/core/src/mill/eval/PathRef.scala
index 168eaa9a..0fbc18f8 100644
--- a/core/src/mill/eval/PathRef.scala
+++ b/core/src/mill/eval/PathRef.scala
@@ -4,10 +4,11 @@ import java.io.IOException
 import java.nio.file.attribute.BasicFileAttributes
 import java.nio.file.{FileVisitResult, FileVisitor}
 import java.nio.{file => jnio}
-import java.security.MessageDigest
+import java.security.{DigestOutputStream, MessageDigest}
+
 import upickle.default.{ReadWriter => RW}
 import ammonite.ops.Path
-import mill.util.JsonFormatters
+import mill.util.{DummyOutputStream, IO, JsonFormatters}
 
 
 /**
@@ -23,8 +24,7 @@ object PathRef{
   def apply(path: ammonite.ops.Path, quick: Boolean = false) = {
     val sig = {
       val digest = MessageDigest.getInstance("MD5")
-
-      val buffer = new Array[Byte](16 * 1024)
+      val digestOut = new DigestOutputStream(DummyOutputStream, digest)
       jnio.Files.walkFileTree(
         path.toNIO,
         new FileVisitor[jnio.Path] {
@@ -43,16 +43,7 @@ object PathRef{
               digest.update(value.toByte)
             }else {
               val is = jnio.Files.newInputStream(file)
-
-              def rec(): Unit = {
-                val length = is.read(buffer)
-                if (length != -1) {
-                  digest.update(buffer, 0, length)
-                  rec()
-                }
-              }
-              rec()
-
+              IO.stream(is, digestOut)
               is.close()
             }
             FileVisitResult.CONTINUE
diff --git a/core/src/mill/util/DummyInputStream.scala b/core/src/mill/util/DummyInputStream.scala
deleted file mode 100644
index 310b358b..00000000
--- a/core/src/mill/util/DummyInputStream.scala
+++ /dev/null
@@ -1,5 +0,0 @@
-package mill.util
-
-import java.io.ByteArrayInputStream
-
-object DummyInputStream extends ByteArrayInputStream(Array())
\ No newline at end of file
diff --git a/core/src/mill/util/IO.scala b/core/src/mill/util/IO.scala
new file mode 100644
index 00000000..833e52c7
--- /dev/null
+++ b/core/src/mill/util/IO.scala
@@ -0,0 +1,32 @@
+package mill.util
+
+import java.io.{InputStream, OutputStream}
+
+import scala.tools.nsc.interpreter.OutputStream
+
+/**
+  * Misc IO utilities, eventually probably should be pushed upstream into
+  * ammonite-ops
+  */
+object IO {
+  def stream(src: InputStream, dest: OutputStream) = {
+    val buffer = new Array[Byte](4096)
+    while ( {
+      src.read(buffer) match {
+        case -1 => false
+        case n =>
+          dest.write(buffer, 0, n)
+          true
+      }
+    }) ()
+  }
+}
+
+import java.io.{ByteArrayInputStream, OutputStream}
+
+object DummyInputStream extends ByteArrayInputStream(Array())
+object DummyOutputStream extends OutputStream{
+  override def write(b: Int) = ()
+  override def write(b: Array[Byte]) = ()
+  override def write(b: Array[Byte], off: Int, len: Int) = ()
+}