From 76506bbb731ca10119bbe37cf7718d327d5d2ff4 Mon Sep 17 00:00:00 2001
From: paltherr <paltherr@epfl.ch>
Date: Thu, 26 Feb 2004 16:42:42 +0000
Subject: - Added ClosureHistory.java

---
 config/list/compiler.lst                  |  1 +
 sources/scalac/symtab/ClosureHistory.java | 73 +++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 sources/scalac/symtab/ClosureHistory.java

diff --git a/config/list/compiler.lst b/config/list/compiler.lst
index 65c2710ebf..ebbad6cd93 100644
--- a/config/list/compiler.lst
+++ b/config/list/compiler.lst
@@ -87,6 +87,7 @@ symtab/classfile/SymblParser.java
 symtab/classfile/Pickle.java
 symtab/classfile/UnPickle.java
 
+symtab/ClosureHistory.java
 symtab/Definitions.java
 symtab/EntryTags.java
 symtab/Kinds.java
diff --git a/sources/scalac/symtab/ClosureHistory.java b/sources/scalac/symtab/ClosureHistory.java
new file mode 100644
index 0000000000..8825fb3e20
--- /dev/null
+++ b/sources/scalac/symtab/ClosureHistory.java
@@ -0,0 +1,73 @@
+/*     ____ ____  ____ ____  ______                                     *\
+**    / __// __ \/ __// __ \/ ____/    SOcos COmpiles Scala             **
+**  __\_ \/ /_/ / /__/ /_/ /\_ \       (c) 2002, LAMP/EPFL              **
+** /_____/\____/\___/\____/____/                                        **
+\*                                                                      */
+
+// $Id$
+
+package scalac.symtab;
+
+import java.util.Iterator;
+import java.util.TreeMap;
+
+import scalac.Global;
+import scalac.framework.History;
+import scalac.util.Debug;
+
+/** This class implements a closure history. */
+public class ClosureHistory extends History {
+
+    //########################################################################
+    // Protected Methods
+
+    /** Transforms given closure into closure at next phase. */
+    protected Object transformValue(Object owner, Object value){
+        Type[] closure = (Type[])value;
+        for (int i = 0; i < closure.length; i++) {
+            Symbol symbol = closure[i].symbol();
+            // !!! symbol.nextInfoHasChanged() would be better
+            if (symbol.info() != symbol.nextInfo())
+                return super.transformValue(owner, closure);
+        }
+        return closure;
+    }
+
+    /** Computes the closure at current phase. */
+    protected Object computeValue(Object owner) {
+        Symbol clasz = (Symbol)owner;
+        TreeMap parents = new TreeMap(SymbolComparator.instance);
+        addParents(parents, clasz.info());
+        Type[] closure = new Type[1 + parents.size()];
+        Iterator types = parents.values().iterator();
+        closure[0] = clasz.type();
+        for (int i = 1; i < closure.length; i++)
+            closure[i] = (Type)types.next();
+        return closure;
+    }
+
+    //########################################################################
+    // Private Functions
+
+    /** Adds all parents of given type to given parent table. */
+    private static void addParents(TreeMap/*<Symbol,Type>*/ table, Type type) {
+        switch (type) {
+        case ErrorType:
+            return;
+        case TypeRef(_, Symbol symbol, _):
+            Type.Map map = Type.getThisTypeMap(symbol, type);
+            Type[] closure = symbol.closure();
+            for (int i = 0; i < closure.length; i++)
+                table.put(closure[i].symbol(), map.apply(closure[i]));
+            return;
+        case CompoundType(Type[] parents, _):
+            for (int i = 0; i < parents.length; i++)
+                addParents(table, parents[i]);
+            return;
+        default:
+            throw Debug.abort("illegal case", type);
+        }
+    }
+
+    //########################################################################
+}
-- 
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