Deduplicate EnumSets of UseScopes

sbt · May 22, 2020 · f7e1812 · f7e1812
1 parent 68011f8
commit f7e1812
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/internal/zinc-core/src/main/scala/sbt/internal/inc/UsedName.scala b/internal/zinc-core/src/main/scala/sbt/internal/inc/UsedName.scala
@@ -12,12 +12,15 @@
 package sbt.internal.inc
 
 import java.util
+import java.util.concurrent.ConcurrentHashMap
 
 import xsbti.UseScope
 
 case class UsedName private (name: String, scopes: util.EnumSet[UseScope])
 
 object UsedName {
+  private[this] val internedUseUseScope =
+    new ConcurrentHashMap[util.EnumSet[UseScope], util.EnumSet[UseScope]]()
 
   def apply(name: String, scopes: Iterable[UseScope] = Nil): UsedName = {
     val useScopes = util.EnumSet.noneOf(classOf[UseScope])
@@ -27,7 +30,8 @@ object UsedName {
 
   def make(name: String, useScopes: util.EnumSet[UseScope]): UsedName = {
     val escapedName = escapeControlChars(name)
-    new UsedName(escapedName, useScopes)
+    val interned = internedUseUseScope.computeIfAbsent(useScopes, x => x)
+    new UsedName(escapedName, interned)
   }
 
   private def escapeControlChars(name: String) = {