Get rid of another map built in FastJarHandler

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/jarfs/FastJarHandler.kt

@@ -31,7 +31,6 @@ class FastJarHandler(val fileSystem: FastJarFileSystem, path: String) {
             }
         }
 
-        val childrenMap = HashMap<FastJarVirtualFile, MutableList<VirtualFile>>(ourEntryMap.size)
         myRoot = FastJarVirtualFile(this, "", -1, null)
 
         val filesByRelativePath = HashMap<String, FastJarVirtualFile>(ourEntryMap.size)
@@ -41,13 +40,8 @@ class FastJarHandler(val fileSystem: FastJarFileSystem, path: String) {
             getOrCreateFile(info, filesByRelativePath)
         }
 
-        for (child in filesByRelativePath.values) {
-            val parent = child.parent as? FastJarVirtualFile ?: continue
-            childrenMap.getOrPut(parent) { mutableListOf() }.add(child)
-        }
-
-        for ((key, childList) in childrenMap) {
-            key.children = childList.toTypedArray()
+        for (node in filesByRelativePath.values) {
+            node.initChildrenArrayFromList()
         }
     }
 

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/jarfs/FastJarVirtualFile.kt

@@ -17,12 +17,19 @@ internal class FastJarVirtualFile(
     private val myHandler: FastJarHandler,
     private val myName: CharSequence,
     private val myLength: Int,
-    private val myParent: VirtualFile?
+    private val myParent: FastJarVirtualFile?
 ) : VirtualFile() {
 
-    private var myChildren = EMPTY_ARRAY
-    fun setChildren(children: Array<VirtualFile>) {
-        myChildren = children
+    private var myChildrenArray = EMPTY_ARRAY
+    private val myChildrenList: MutableList<VirtualFile> = mutableListOf()
+
+    init {
+        myParent?.myChildrenList?.add(this)
+    }
+
+    fun initChildrenArrayFromList() {
+        myChildrenArray = myChildrenList.toTypedArray()
+        myChildrenList.clear()
     }
 
     override fun getName(): String {
@@ -68,7 +75,7 @@ internal class FastJarVirtualFile(
     }
 
     override fun getChildren(): Array<VirtualFile> {
-        return myChildren
+        return myChildrenArray
     }
 
     @Throws(IOException::class)