fix: make sure JVM and SJS TASTy is alined

Author: hamzaremmal

library-js/src/scala/Symbol.scala

@@ -39,15 +39,14 @@ final class Symbol private (val name: String) extends Serializable {
   override def equals(other: Any) = this eq other.asInstanceOf[AnyRef]
 }
 
-// Modified to use Scala.js specific cache
-object Symbol extends JSUniquenessCache[Symbol] {
+object Symbol extends UniquenessCache[String, Symbol] {
   override def apply(name: String): Symbol = super.apply(name)
   protected def valueFromKey(name: String): Symbol = new Symbol(name)
   protected def keyFromValue(sym: Symbol): Option[String] = Some(sym.name)
 }
 
-private[scala] abstract class JSUniquenessCache[V]
-{
+// Modified to use Scala.js specific cache
+private[scala] abstract class UniquenessCache[K, V >: Null] {
   private val cache = js.Dictionary.empty[V]
 
   protected def valueFromKey(k: String): V
@@ -57,59 +56,4 @@ private[scala] abstract class JSUniquenessCache[V]
     cache.getOrElseUpdate(name, valueFromKey(name))
 
   def unapply(other: V): Option[String] = keyFromValue(other)
-}
-
-/** This is private so it won't appear in the library API, but
-  * abstracted to offer some hope of reusability.  */
-/* DELETED for Scala.js
-private[scala] abstract class UniquenessCache[K >: js.String, V >: Null]
-{
-
-  import java.lang.ref.WeakReference
-  import java.util.WeakHashMap
-  import java.util.concurrent.locks.ReentrantReadWriteLock
-
-  private[this] val rwl = new ReentrantReadWriteLock()
-  private[this] val rlock = rwl.readLock
-  private[this] val wlock = rwl.writeLock
-  private[this] val map = new WeakHashMap[K, WeakReference[V]]
-
-  protected def valueFromKey(k: K): V
-  protected def keyFromValue(v: V): Option[K]
-
-  def apply(name: K): V = {
-    def cached(): V = {
-      rlock.lock
-      try {
-        val reference = map get name
-        if (reference == null) null
-        else reference.get  // will be null if we were gc-ed
-      }
-      finally rlock.unlock
-    }
-    def updateCache(): V = {
-      wlock.lock
-      try {
-        val res = cached()
-        if (res != null) res
-        else {
-          // If we don't remove the old String key from the map, we can
-          // wind up with one String as the key and a different String as
-          // the name field in the Symbol, which can lead to surprising GC
-          // behavior and duplicate Symbols. See scala/bug#6706.
-          map remove name
-          val sym = valueFromKey(name)
-          map.put(name, new WeakReference(sym))
-          sym
-        }
-      }
-      finally wlock.unlock
-    }
-
-    val res = cached()
-    if (res == null) updateCache()
-    else res
-  }
-  def unapply(other: V): Option[K] = keyFromValue(other)
-}
-*/
+}