add ability to define jar manifest (#634)

* add capability to define jar manifest

* Don't use the custom manifest for doc-only jars

This is to pass test mill.scalalib.HelloWorldTests.scalaDocOptions

* Add JarManifest.Default and fix the build


rebase fix

4 files changed, 64 insertions, 21 deletions

diff --git a/build.sc b/build.sc
index cba26933..2515abda 100755
--- a/build.sc
+++ b/build.sc
@@ -8,6 +8,7 @@ import mill._
 import mill.scalalib._
 import publish._
 import mill.modules.Jvm.createAssembly
+
 trait MillPublishModule extends PublishModule{
 
   def artifactName = "mill-" + super.artifactName()
diff --git a/main/src/modules/Jvm.scala b/main/src/modules/Jvm.scala
index 39813217..fb93b839 100644
--- a/main/src/modules/Jvm.scala
+++ b/main/src/modules/Jvm.scala
@@ -6,7 +6,7 @@ import java.net.URI
 import java.nio.file.{FileSystems, Files, StandardOpenOption}
 import java.nio.file.attribute.PosixFilePermission
 import java.util.Collections
-import java.util.jar.{JarEntry, JarFile, JarOutputStream}
+import java.util.jar.{Attributes, JarEntry, JarFile, JarOutputStream, Manifest}
 
 import coursier.{Dependency, Fetch, Repository, Resolution}
 import coursier.util.{Gather, Task}
@@ -19,6 +19,7 @@ import mill.api.Loose.Agg
 
 import scala.collection.mutable
 import scala.collection.JavaConverters._
+import upickle.default.{macroRW, ReadWriter => RW}
 
 object Jvm {
   /**
@@ -189,15 +190,16 @@ object Jvm {
     }
   }
 
-
-  private def createManifest(mainClass: Option[String]) = {
-    val m = new java.util.jar.Manifest()
-    m.getMainAttributes.put(java.util.jar.Attributes.Name.MANIFEST_VERSION, "1.0")
-    m.getMainAttributes.putValue( "Created-By", "Scala mill" )
-    mainClass.foreach(
-      m.getMainAttributes.put(java.util.jar.Attributes.Name.MAIN_CLASS, _)
-    )
-    m
+  def createManifest(mainClass: Option[String]): JarManifest = {
+    val main =
+      Map[String,String](
+        java.util.jar.Attributes.Name.MANIFEST_VERSION.toString -> "1.0",
+        "Created-By" -> "Scala mill"
+      ) ++
+      mainClass.map(mc =>
+        Map(java.util.jar.Attributes.Name.MAIN_CLASS.toString -> mc)
+      ).getOrElse(Map.empty)
+    JarManifest(main)
   }
 
   /**
@@ -214,7 +216,7 @@ object Jvm {
     * @return - a `PathRef` for the created jar.
     */
   def createJar(inputPaths: Agg[os.Path],
-                mainClass: Option[String] = None,
+                manifest: JarManifest = JarManifest.Default,
                 fileFilter: (os.Path, os.RelPath) => Boolean = (p: os.Path, r: os.RelPath) => true)
                (implicit ctx: Ctx.Dest): PathRef = {
     val outputPath = ctx.dest / "out.jar"
@@ -224,7 +226,7 @@ object Jvm {
     seen.add(os.rel / "META-INF" / "MANIFEST.MF")
     val jar = new JarOutputStream(
       new FileOutputStream(outputPath.toIO),
-      createManifest(mainClass)
+      manifest.build
     )
 
     try{
@@ -251,7 +253,7 @@ object Jvm {
   }
 
   def createAssembly(inputPaths: Agg[os.Path],
-                     mainClass: Option[String] = None,
+                     manifest: JarManifest = JarManifest.Default,
                      prependShellScript: String = "",
                      base: Option[os.Path] = None,
                      assemblyRules: Seq[Assembly.Rule] = Assembly.defaultRules)
@@ -269,7 +271,6 @@ object Jvm {
 
     val zipFs = FileSystems.newFileSystem(URI.create(baseUri), hm)
 
-    val manifest = createManifest(mainClass)
     val manifestPath = zipFs.getPath(JarFile.MANIFEST_NAME)
     Files.createDirectories(manifestPath.getParent)
     val manifestOut = Files.newOutputStream(
@@ -277,7 +278,7 @@ object Jvm {
       StandardOpenOption.TRUNCATE_EXISTING,
       StandardOpenOption.CREATE
     )
-    manifest.write(manifestOut)
+    manifest.build.write(manifestOut)
     manifestOut.close()
 
     Assembly.groupAssemblyEntries(inputPaths, assemblyRules).view
@@ -332,6 +333,7 @@ object Jvm {
     outputStream.close()
     is.close()
   }
+  
   def universalScript(shellCommands: String,
                       cmdCommands: String,
                       shebang: Boolean = false): String = {
@@ -561,4 +563,32 @@ object Jvm {
     }
   }
 
+  object JarManifest {
+    implicit val jarManifestRW: RW[JarManifest] = upickle.default.macroRW
+    final val Default = createManifest(None)
+  }
+
+  /** Represents a JAR manifest.
+    * @param main the main manifest attributes
+    * @param groups additional attributes for named entries
+    */
+  final case class JarManifest(main: Map[String,String] = Map.empty, groups: Map[String, Map[String,String]] = Map.empty) {
+    def add(entries: (String,String)*): JarManifest = copy(main = main ++ entries)
+    def addGroup(group: String, entries: (String,String)*): JarManifest =
+      copy(groups = groups + (group -> (groups.getOrElse(group, Map.empty) ++ entries)))
+
+    /** Constructs a [[java.util.jar.Manifest]] from this JarManifest. */
+    def build: Manifest = {
+      val manifest = new Manifest
+      val mainAttributes = manifest.getMainAttributes
+      main.foreach{case(key,value) => mainAttributes.putValue(key, value)}
+      val entries = manifest.getEntries
+      for((group, attribs) <- groups) {
+        val attrib = new Attributes
+        attribs.foreach{case(key,value) => attrib.putValue(key, value)}
+        entries.put(group, attrib)
+      }
+      manifest
+    }
+  }
 }
diff --git a/main/test/src/eval/JavaCompileJarTests.scala b/main/test/src/eval/JavaCompileJarTests.scala
index 0f9002df..e243b915 100644
--- a/main/test/src/eval/JavaCompileJarTests.scala
+++ b/main/test/src/eval/JavaCompileJarTests.scala
@@ -2,6 +2,7 @@ package mill.eval
 
 import mill.define.{Discover, Input, Target, Task}
 import mill.modules.Jvm
+import mill.modules.Jvm.JarManifest
 import mill.api.Ctx.Dest
 import mill.{Module, T}
 import mill.util.{DummyLogger, TestEvaluator, TestUtil}
@@ -9,6 +10,7 @@ import mill.api.Strict.Agg
 import mill.api.Loose
 import utest._
 import mill._
+
 object JavaCompileJarTests extends TestSuite{
   def compileAll(sources: mill.api.Loose.Agg[PathRef])(implicit ctx: Dest) = {
     os.makeDir.all(ctx.dest)
@@ -39,7 +41,7 @@ object JavaCompileJarTests extends TestSuite{
         def classFiles = T{ compileAll(allSources()) }
         def jar = T{ Jvm.createJar(Loose.Agg(classFiles().path) ++ resourceRoot().map(_.path)) }
         // Test createJar() with optional file filter.
-        def filterJar(fileFilter: (os.Path, os.RelPath) => Boolean) = T{ Jvm.createJar(Loose.Agg(classFiles().path) ++ resourceRoot().map(_.path), None, fileFilter) }
+        def filterJar(fileFilter: (os.Path, os.RelPath) => Boolean) = T{ Jvm.createJar(Loose.Agg(classFiles().path) ++ resourceRoot().map(_.path), JarManifest.Default, fileFilter) }
 
         def run(mainClsName: String) = T.command{
           os.proc('java, "-Duser.language=en", "-cp", classFiles().path, mainClsName).call()
diff --git a/scalalib/src/JavaModule.scala b/scalalib/src/JavaModule.scala
index 7b373650..c7066d15 100644
--- a/scalalib/src/JavaModule.scala
+++ b/scalalib/src/JavaModule.scala
@@ -1,6 +1,9 @@
 package mill
 package scalalib
 
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+
 import coursier.Repository
 import mill.define.Task
 import mill.define.TaskModule
@@ -257,6 +260,14 @@ trait JavaModule extends mill.Module with TaskModule { outer =>
   }
 
   /**
+    * Creates a manifest representation which can be modifed or replaced
+    * The default implementation just adds the `Manifest-Version`, `Main-Class` and `Created-By` attributes
+    */
+  def manifest = T{
+    Jvm.createManifest(finalMainClassOpt().toOption)
+  }
+
+  /**
     * Build the assembly for upstream dependencies separate from the current
     * classpath
     *
@@ -266,7 +277,7 @@ trait JavaModule extends mill.Module with TaskModule { outer =>
   def upstreamAssembly = T{
     createAssembly(
       upstreamAssemblyClasspath().map(_.path),
-      mainClass(),
+      manifest(),
       assemblyRules = assemblyRules
     )
   }
@@ -278,7 +289,7 @@ trait JavaModule extends mill.Module with TaskModule { outer =>
   def assembly = T{
     createAssembly(
       Agg.from(localClasspath().map(_.path)),
-      finalMainClassOpt().toOption,
+      manifest(),
       prependShellScript(),
       Some(upstreamAssembly().path),
       assemblyRules
@@ -292,7 +303,7 @@ trait JavaModule extends mill.Module with TaskModule { outer =>
   def jar = T{
     createJar(
       localClasspath().map(_.path).filter(os.exists),
-      mainClass()
+      manifest()
     )
   }
 
@@ -345,7 +356,7 @@ trait JavaModule extends mill.Module with TaskModule { outer =>
     * The source jar, containing only source code for publishing to Maven Central
     */
   def sourceJar = T {
-    createJar((allSources() ++ resources()).map(_.path).filter(os.exists))
+    createJar((allSources() ++ resources()).map(_.path).filter(os.exists), manifest())
   }
 
   /**
@@ -626,4 +637,3 @@ object TestModule{
     }
   }
 }
-