revamp loop feature

now CBT and builds pass their file names to the current build
via the context. The build then simply blocks until any file changes.
Then it returns with a special exit code, which the bash script picks
up and restarts CBT. Thats works well for looping over project files.
It works less well for looping over builds and CBT itself. For this
a build has to success once, so that the .cbt-loop.tmp file exists.
Then looping works for cbt and builds, but the file list is not
updated in case of compile errors, etc.

Fixes
- https://github.com/cvogt/cbt/issues/406
- https://github.com/cvogt/cbt/issues/405
- https://github.com/cvogt/cbt/issues/202
- https://github.com/cvogt/cbt/issues/50
- https://github.com/cvogt/cbt/issues/22

We should improve for 1.0 in https://github.com/cvogt/cbt/issues/419
to handle looping over build files and cbt itself smarter.

1 files changed, 19 insertions, 1 deletions

diff --git a/stage2/BasicBuild.scala b/stage2/BasicBuild.scala
index 68bda15..bc6f9d9 100644
--- a/stage2/BasicBuild.scala
+++ b/stage2/BasicBuild.scala
@@ -2,6 +2,7 @@ package cbt
 
 import java.io._
 import java.net._
+import java.nio.file._
 
 class BasicBuild(final val context: Context) extends BaseBuild
 trait BaseBuild extends BuildInterface with DependencyImplementation with TriggerLoop with SbtDependencyDsl{
@@ -124,7 +125,11 @@ trait BaseBuild extends BuildInterface with DependencyImplementation with Trigge
     pathToNestedBuild: _*
   )
 
-  def triggerLoopFiles: Seq[File] = sources ++ transitiveDependencies.collect{ case b: TriggerLoop => b.triggerLoopFiles }.flatten
+  def triggerLoopFiles: Set[File] = (
+    context.triggerLoopFiles
+    ++ sources
+    ++ transitiveDependencies.collect{ case b: TriggerLoop => b.triggerLoopFiles }.flatten
+  )
 
   def localJars: Seq[File] =
     Seq(projectDirectory ++ "/lib")
@@ -318,4 +323,17 @@ trait BaseBuild extends BuildInterface with DependencyImplementation with Trigge
   final def crossScalaVersionsArray = Array(scalaVersion)
 
   def publish: Seq[URL] = Seq()
+
+  def loop = {
+    lib.callReflective(this, context.args.headOption, context.copy(args=context.args.drop(1)))
+    val files = triggerLoopFiles
+    lib.watch{ () =>
+      logger.loop("Looping change detection over:\n - "++files.mkString("\n - "))
+      files
+    }()
+    context.loopFile.getParentFile.mkdirs
+    lib.write( context.loopFile, files.mkString("\n"), StandardOpenOption.CREATE )
+
+    ExitCode(253) // signal bash script to restart
+  }
 }