Better terminal output

cache/src/main/scala/coursier/TermDisplay.scala

@@ -19,6 +19,7 @@ class TermDisplay(
   private val fallbackRefreshInterval = 1000
 
   private val lock = new AnyRef
+  private var currentHeight = 0
   private val t = new Thread("TermDisplay") {
     override def run() = lock.synchronized {
 
@@ -60,7 +61,9 @@ class TermDisplay(
       }
 
 
-      @tailrec def helper(lineCount: Int): Unit =
+      @tailrec def helper(lineCount: Int): Unit = {
+        currentHeight = lineCount
+
         Option(q.poll(100L, TimeUnit.MILLISECONDS)) match {
           case None => helper(lineCount)
           case Some(Left(())) => // poison pill
@@ -100,6 +103,7 @@ class TermDisplay(
             Thread.sleep(refreshInterval)
             helper(downloads0.length)
         }
+      }
 
 
       @tailrec def fallbackHelper(previous: Set[String]): Unit =
@@ -153,6 +157,13 @@ class TermDisplay(
   }
 
   def stop(): Unit = {
+    for (_ <- 0 until currentHeight) {
+      ansi.clearLine(2)
+      ansi.down(1)
+    }
+    for (_ <- 0 until currentHeight) {
+      ansi.up(1)
+    }
     q.put(Left(()))
     lock.synchronized(())
   }

cli/src/main/scala/coursier/cli/Helper.scala

@@ -213,7 +213,6 @@ class Helper(
       Some(new TermDisplay(new OutputStreamWriter(System.err)))
     else
       None
-  logger.foreach(_.init())
 
   val fetchs = cachePolicies.map(p =>
     Cache.fetch(caches, p, logger = logger, pool = pool)
@@ -246,6 +245,7 @@ class Helper(
     }
   }
 
+  logger.foreach(_.init())
 
   val res = startRes
     .process
@@ -341,24 +341,26 @@ class Helper(
         Some(new TermDisplay(new OutputStreamWriter(System.err)))
       else
         None
-    logger.foreach(_.init())
+
+    if (verbose0 >= 1 && artifacts.nonEmpty)
+      println(s"Found ${artifacts.length} artifacts")
+
     val tasks = artifacts.map(artifact =>
       (Cache.file(artifact, caches, cachePolicies.head, logger = logger, pool = pool) /: cachePolicies.tail)(
         _ orElse Cache.file(artifact, caches, _, logger = logger, pool = pool)
       ).run.map(artifact.->)
     )
-    def printTask = Task {
-      if (verbose0 >= 1 && artifacts.nonEmpty)
-        println(s"Found ${artifacts.length} artifacts")
-    }
-    val task = printTask.flatMap(_ => Task.gatherUnordered(tasks))
+
+    logger.foreach(_.init())
+
+    val task = Task.gatherUnordered(tasks)
+
+    logger.foreach(_.stop())
 
     val results = task.run
     val errors = results.collect{case (artifact, -\/(err)) => artifact -> err }
     val files0 = results.collect{case (artifact, \/-(f)) => f }
 
-    logger.foreach(_.stop())
-
     if (errors.nonEmpty) {
       println(s"${errors.size} error(s):")
       for ((artifact, error) <- errors) {

plugin/src/main/scala/coursier/Tasks.scala

@@ -251,16 +251,17 @@ object Tasks {
 
         val pool = Executors.newFixedThreadPool(parallelDownloads, Strategy.DefaultDaemonThreadFactory)
 
-        val logger = new TermDisplay(
+        def createLogger() = new TermDisplay(
           new OutputStreamWriter(System.err),
           fallbackMode = sys.env.get("COURSIER_NO_TERM").nonEmpty
         )
-        logger.init()
+
+        val resLogger = createLogger()
 
         val fetch = coursier.Fetch(
           repositories,
-          Cache.fetch(caches, CachePolicy.LocalOnly, checksums = checksums, logger = Some(logger), pool = pool),
-          Cache.fetch(caches, cachePolicy, checksums = checksums, logger = Some(logger), pool = pool)
+          Cache.fetch(caches, CachePolicy.LocalOnly, checksums = checksums, logger = Some(resLogger), pool = pool),
+          Cache.fetch(caches, cachePolicy, checksums = checksums, logger = Some(resLogger), pool = pool)
         )
 
         def depsRepr(deps: Seq[(String, Dependency)]) =
@@ -290,6 +291,8 @@ object Tasks {
           for (depRepr <- depsRepr(currentProject.dependencies))
             errPrintln(s"  $depRepr")
 
+        resLogger.init()
+
         val res = startRes
           .process
           .run(fetch, maxIterations)
@@ -297,6 +300,7 @@ object Tasks {
           .leftMap(ex => throw new Exception(s"Exception during resolution", ex))
           .merge
 
+        resLogger.stop()
 
 
         if (!res.isDone)
@@ -366,13 +370,17 @@ object Tasks {
             case Some(cl) => res.classifiersArtifacts(cl)
           }
 
+        val artifactsLogger = createLogger()
+
         val artifactFileOrErrorTasks = allArtifacts.toVector.map { a =>
-          Cache.file(a, caches, cachePolicy, checksums = artifactsChecksums, logger = Some(logger), pool = pool).run.map((a, _))
+          Cache.file(a, caches, cachePolicy, checksums = artifactsChecksums, logger = Some(artifactsLogger), pool = pool).run.map((a, _))
         }
 
         if (verbosity >= 0)
           errPrintln(s"Fetching artifacts")
 
+        artifactsLogger.init()
+
         val artifactFilesOrErrors = Task.gatherUnordered(artifactFileOrErrorTasks).attemptRun match {
           case -\/(ex) =>
             throw new Exception(s"Error while downloading / verifying artifacts", ex)
@@ -380,6 +388,8 @@ object Tasks {
             l.toMap
         }
 
+        artifactsLogger.stop()
+
         if (verbosity >= 0)
           errPrintln(s"Fetching artifacts: done")