Optimize knownProducts for direct-to-JAR compilation

internal/zinc-classfile/src/main/scala/sbt/internal/inc/JarUtils.scala

@@ -46,17 +46,24 @@ object JarUtils {
    * "C:\develop\zinc\target\output.jar!sbt\internal\inc\Compile.class"
    */
   class ClassInJar(override val toString: String) extends AnyVal {
-    def toClassFilePath: Option[ClassFilePath] = splitJarReference._2
+    def toClassFilePath: Option[ClassFilePath] = Option(toClassFilePathOrNull)
+    def toClassFilePathOrNull: ClassFilePath = {
+      val idx = toString.indexOf('!')
+      if (idx < 0) null
+      else toClassFilePath(idx)
+    }
     def splitJarReference: (File, Option[ClassFilePath]) = {
-      if (toString.contains("!")) {
-        val Array(jar, cls) = toString.split("!")
-        // ClassInJar stores RelClass part with File.separatorChar, however actual paths in zips always use '/'
-        val classFilePath = cls.replace('\\', '/')
-        (new File(jar), Some(classFilePath))
-      } else {
+      val idx = toString.indexOf('!')
+      if (idx < 0) {
         (new File(toString), None)
+      } else {
+        (new File(toString.substring(0, idx)), Some(toClassFilePath(idx)))
       }
     }
+    private def toClassFilePath(idx: Int): String = {
+      // ClassInJar stores RelClass part with File.separatorChar, however actual paths in zips always use '/'
+      toString.substring(idx + 1).replace('\\', '/')
+    }
 
     /**
      * Wraps the string value inside a java.io.File object.

internal/zinc-core/src/main/scala/sbt/internal/inc/Incremental.scala

@@ -22,7 +22,6 @@ import sbt.util.{ InterfaceUtil, Level, Logger }
 import sbt.util.InterfaceUtil.{ jo2o, t2 }
 import scala.collection.JavaConverters._
 import scala.util.control.NonFatal
-import scala.collection.parallel.immutable.ParVector
 import xsbti.{ FileConverter, Position, Problem, Severity, UseScope, VirtualFile, VirtualFileRef }
 import xsbt.api.{ APIUtil, HashAPI, NameHashing }
 import xsbti.api._
@@ -1086,28 +1085,27 @@ private final class AnalysisCallback(
 
   private def knownProducts(merged: Analysis) = {
     // List classes defined in the files that were compiled in this run.
-    val ps = java.util.concurrent.ConcurrentHashMap.newKeySet[String]
-    val knownProducts: ParVector[VirtualFileRef] =
-      new ParVector(merged.relations.allSources.toVector)
-        .flatMap(merged.relations.products)
-    // extract product paths in parallel
-    jo2o(output.getSingleOutputAsPath) match {
-      case Some(so) if so.getFileName.toString.endsWith(".jar") =>
-        knownProducts foreach { product =>
-          new JarUtils.ClassInJar(product.id).toClassFilePath foreach { path =>
+    val ps: java.util.Set[String] = new java.util.HashSet[String]()
+    val knownProducts: collection.Set[VirtualFileRef] = merged.relations.allProducts
+
+    // extract product paths
+    val so = jo2o(output.getSingleOutputAsPath).getOrElse(sys.error(s"unsupported output $output"))
+    val isJarOutput = so.getFileName.toString.endsWith(".jar")
+    knownProducts foreach { product =>
+      if (isJarOutput) {
+        new JarUtils.ClassInJar(product.id).toClassFilePathOrNull match {
+          case null =>
+          case path =>
             ps.add(path.replace('\\', '/'))
-          }
         }
-      case Some(so) =>
-        knownProducts foreach { product =>
-          val productPath = converter.toPath(product)
-          try {
-            ps.add(so.relativize(productPath).toString.replace('\\', '/'))
-          } catch {
-            case NonFatal(_) => ps.add(product.id)
-          }
+      } else {
+        val productPath = converter.toPath(product)
+        try {
+          ps.add(so.relativize(productPath).toString.replace('\\', '/'))
+        } catch {
+          case NonFatal(_) => ps.add(product.id)
         }
-      case _ => sys.error(s"unsupported output $output")
+      }
     }
     ps
   }