Convert more mutable.HashMaps to util.HashMaps (1)

Author: odersky

compiler/src/dotty/tools/dotc/core/tasty/CommentUnpickler.scala

@@ -1,19 +1,19 @@
-package dotty.tools.dotc.core.tasty
+package dotty.tools.dotc
+package core.tasty
 
-import dotty.tools.dotc.core.Comments.Comment
-import dotty.tools.dotc.util.Spans.Span
+import core.Comments.Comment
+import util.Spans.Span
+import util.HashMap
 
 import dotty.tools.tasty.{TastyReader, TastyBuffer}
 import TastyBuffer.Addr
 
-import scala.collection.mutable.HashMap
-
 import java.nio.charset.Charset
 
 class CommentUnpickler(reader: TastyReader) {
   import reader._
 
-  private[tasty] lazy val comments: Map[Addr, Comment] = {
+  private[tasty] lazy val comments: HashMap[Addr, Comment] = {
     val comments = new HashMap[Addr, Comment]
     while (!isAtEnd) {
       val addr = readAddr()
@@ -25,7 +25,7 @@ class CommentUnpickler(reader: TastyReader) {
         comments(addr) = Comment(position, rawComment)
       }
     }
-    comments.toMap
+    comments
   }
 
   def commentAt(addr: Addr): Option[Comment] =

compiler/src/dotty/tools/dotc/core/tasty/PositionUnpickler.scala

@@ -15,14 +15,14 @@ import Names.TermName
 class PositionUnpickler(reader: TastyReader, nameAtRef: NameRef => TermName) {
   import reader._
 
-  private var mySpans: mutable.HashMap[Addr, Span] = _
-  private var mySourcePaths: mutable.HashMap[Addr, String] = _
+  private var mySpans: util.HashMap[Addr, Span] = _
+  private var mySourcePaths: util.HashMap[Addr, String] = _
   private var isDefined = false
 
   def ensureDefined(): Unit = {
     if (!isDefined) {
-      mySpans = new mutable.HashMap[Addr, Span]
-      mySourcePaths = new mutable.HashMap[Addr, String]
+      mySpans = util.HashMap[Addr, Span]()
+      mySourcePaths = util.HashMap[Addr, String]()
       var curIndex = 0
       var curStart = 0
       var curEnd = 0
@@ -50,12 +50,12 @@ class PositionUnpickler(reader: TastyReader, nameAtRef: NameRef => TermName) {
     }
   }
 
-  private[tasty] def spans: Map[Addr, Span] = {
+  private[tasty] def spans: util.ReadOnlyMap[Addr, Span] = {
     ensureDefined()
     mySpans
   }
 
-  private[tasty] def sourcePaths: Map[Addr, String] = {
+  private[tasty] def sourcePaths: util.ReadOnlyMap[Addr, String] = {
     ensureDefined()
     mySourcePaths
   }

compiler/src/dotty/tools/dotc/util/ReadOnlyMap.scala

@@ -11,6 +11,7 @@ abstract class ReadOnlyMap[Key, Value]:
 
   def iterator: Iterator[(Key, Value)]
   def keysIterator: Iterator[Key]
+  def valuesIterator: Iterator[Value]
 
   def isEmpty: Boolean = size == 0
 
@@ -26,4 +27,15 @@ abstract class ReadOnlyMap[Key, Value]:
 
   def apply(key: Key): Value = lookup(key) match
     case null => throw new NoSuchElementException(s"$key")
-    case v => v.uncheckedNN
+    case v => v.uncheckedNN
+
+  def toArray: Array[(Key, Value)] =
+    val result = new Array[(Key, Value)](size)
+    var idx = 0
+    for pair <- iterator do
+      result(idx) = pair
+      idx += 1
+    result
+
+  def toSeq: Seq[(Key, Value)] = toArray.toSeq
+