start modularizing cbt into libraries

this extracts certain parts of cbt into stand-alone libraries, which can
be published to maven and used outside of cbt.

This also adds scalariform for these parts of the code.

This slows down cbt’s own build a lot because of the number of projects
involved! So we’ll follow this by a bunch of performance tweak commits.

1 files changed, 51 insertions, 0 deletions

diff --git a/internal/plugins/library/Library.scala b/internal/plugins/library/Library.scala
new file mode 100644
index 0000000..a9dec7c
--- /dev/null
+++ b/internal/plugins/library/Library.scala
@@ -0,0 +1,51 @@
+package cbt_internal
+import cbt._
+import java.io._
+import scala.concurrent._
+import scala.concurrent.duration._
+trait Library extends Scalariform with GoogleJavaFormat with DynamicOverrides with AdvancedScala{
+  def inceptionYear: Int
+  def description: String
+  def version = ???
+  override def compile = {
+    googleJavaFormat()
+    scalariform()
+    super.compile
+  }
+
+  def publishIfChanged = newBuild[PublishIfChanged]({s"""
+    def inceptionYear = $inceptionYear
+    def description = ${description.quote}
+    def apply = if(changedInMaster) publish
+  """})
+}
+
+trait PublishIfChanged extends PackageJars with DynamicOverrides with Shared{
+  override def url = super.url ++ "/libraries/" ++ name
+
+  def gitHash = {
+    val p = new ProcessBuilder(
+        "git rev-parse HEAD".split(" "): _*
+    )
+    .directory( projectDirectory )
+    .start
+
+    val sout = new InputStreamReader(p.getInputStream);
+    import scala.concurrent.ExecutionContext.Implicits.global
+    val out = Future(blocking(Iterator.continually(sout.read).takeWhile(_ != -1).map(_.toChar).mkString))
+    p.waitFor
+    val revision = Await.result( out, Duration.Inf ).trim
+    revision
+  }
+  override def version = "rev-"++gitHash
+
+  def changedInMaster = (
+    0 ===
+    new ProcessBuilder(
+        "git diff --exit-code --quiet master..master^ .".split(" "): _*
+    )
+    .directory( projectDirectory )
+    .start
+    .waitFor
+  )
+}