- Added SymbolCloner.java

1 files changed, 94 insertions, 0 deletions

diff --git a/sources/scalac/symtab/SymbolCloner.java b/sources/scalac/symtab/SymbolCloner.java
new file mode 100644
index 0000000000..75108e88b2
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+++ b/sources/scalac/symtab/SymbolCloner.java
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+/*     ____ ____  ____ ____  ______                                     *\
+**    / __// __ \/ __// __ \/ ____/    SOcos COmpiles Scala             **
+**  __\_ \/ /_/ / /__/ /_/ /\_ \       (c) 2002, LAMP/EPFL              **
+** /_____/\____/\___/\____/____/                                        **
+\*                                                                      */
+
+// $Id$
+
+package scalac.symtab;
+
+import java.util.Map;
+import java.util.HashMap;
+
+import scalac.util.FreshNameCreator;
+import scalac.util.Debug;
+
+/**
+ * This class implements a symbol cloner. It automatically determines
+ * the new owner of cloned symbols and keeps track of all cloned
+ * symbols.
+ */
+public class SymbolCloner {
+
+    //########################################################################
+    // Public Fields
+
+    /** The fresh name generator used to rename cloned symbols */
+    public final FreshNameCreator renamer;
+
+    /** A table that maps owners of symbols to owners of cloned symbols */
+    public final Map/*<Symbol,Symbol*/ owners;
+
+    /** A map<cloned,clone> into which cloned symbols are stored */
+    public final Map/*<Symbol,Symbol*/ clones;
+
+    //########################################################################
+    // Public Constructor
+
+    /** Initializes a new instance. */
+    public SymbolCloner(FreshNameCreator renamer) {
+        this(renamer, new HashMap());
+    }
+
+    /** Initializes a new instance. */
+    public SymbolCloner(FreshNameCreator renamer, Map owners) {
+        this(renamer, owners, new HashMap());
+    }
+
+    /** Initializes a new instance. */
+    public SymbolCloner(FreshNameCreator renamer, Map owners, Map clones) {
+        this.renamer = renamer;
+        this.owners = owners;
+        this.clones = clones;
+    }
+
+    //########################################################################
+    // Public Methods - Cloning symbols
+
+    /**
+     * Returns the owner for the clone of the given symbol. The
+     * default implementation returns the clone of the symbol's owner
+     * if that owner has been cloned or else returns the owner
+     * associated to the symbol's owner in the owner table.
+     */
+    public Symbol getOwnerFor(Symbol symbol) {
+        Symbol oldowner = symbol.owner();
+        Object newowner = clones.get(oldowner);
+        if (newowner == null) newowner = owners.get(oldowner);
+        assert newowner != null : Debug.show(symbol);
+        return (Symbol)newowner;
+    }
+
+    /** Clones the given symbol. */
+    public Symbol cloneSymbol(Symbol symbol) {
+        return cloneSymbol(symbol, false);
+    }
+
+    /** Clones the given symbol and renames it rename is true. */
+    public Symbol cloneSymbol(Symbol symbol, boolean rename) {
+        assert !symbol.isPrimaryConstructor() : Debug.show(symbol);
+        assert !symbol.isModuleClass() : Debug.show(symbol);
+        assert !symbol.isClass() : Debug.show(symbol);
+        assert !symbol.isModule() : Debug.show(symbol);
+        assert !owners.containsKey(symbol) : Debug.show(symbol);
+        assert !clones.containsKey(symbol) :
+            Debug.show(symbol) + " -> " + Debug.show(clones.get(symbol));
+        Symbol clone = symbol.cloneSymbol(getOwnerFor(symbol));
+        if (rename) clone.name = renamer.newName(symbol.name);
+        clones.put(symbol, clone);
+        return clone;
+    }
+
+    //########################################################################
+}