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/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
\* */
// $Id$
// $OldId: ExplicitOuterClasses.java,v 1.22 2002/10/17 12:31:56 schinz Exp $
package scalac.transformer;
import java.util.*;
import scalac.*;
import scalac.ast.*;
import scalac.util.*;
import scalac.parser.*;
import scalac.symtab.*;
import scalac.typechecker.*;
import Tree.*;
/**
* Make links from nested classes to their enclosing class explicit.
*
* @author Michel Schinz
* @version 1.0
*/
public class ExplicitOuterClasses extends Transformer {
// Mapping from class constructor symbols to owner field symbols.
protected HashMap/*<Symbol,Symbol>*/ outerMap;
public ExplicitOuterClasses(Global global) {
super(global);
outerMap = global.PHASE.EXPLICITOUTER.outerMap;
}
protected Type addValueParam(Type oldType, Symbol newValueParam) {
switch (oldType) {
case MethodType(Symbol[] vparams, Type result): {
Symbol[] newVParams = new Symbol[vparams.length + 1];
newVParams[0] = newValueParam;
System.arraycopy(vparams, 0, newVParams, 1, vparams.length);
return new Type.MethodType(newVParams, result);
}
case PolyType(Symbol[] tparams, Type result):
return new Type.PolyType(tparams, addValueParam(result, newValueParam));
default:
throw global.fail("invalid type", oldType);
}
}
protected Symbol outerSym(Symbol constSym) {
if (! outerMap.containsKey(constSym)) {
Symbol ownerSym = constSym.enclClass();
Symbol outerSym =
new TermSymbol(constSym.pos, freshOuterName(), constSym, 0);
outerSym.setInfo(ownerSym.type());
outerMap.put(constSym, outerSym);
}
return (Symbol)outerMap.get(constSym);
}
protected Type newConstType(Symbol constSym) {
return addValueParam(constSym.info(), outerSym(constSym));
}
protected LinkedList/*<Symbol>*/ classStack = new LinkedList();
protected LinkedList/*<Symbol>*/ outerLinks = new LinkedList();
protected Name freshOuterName() {
return global.freshNameCreator.newName(Names.OUTER_PREFIX);
}
// Return the given class with an explicit link to its outer
// class, if any.
protected Tree addOuterLink(ClassDef classDef) {
Symbol classSym = classDef.symbol();
Symbol constSym = classSym.constructor();
Symbol outerSym = outerSym(constSym);
assert (outerSym.owner() == constSym) : outerSym;
outerLinks.addFirst(outerSym);
// Add the outer parameter, both to the type and the tree.
Type newConstType = newConstType(constSym);
ValDef[][] vparams = classDef.vparams;
ValDef[] newVParamsI;
if (vparams.length == 0)
newVParamsI = new ValDef[] { gen.ValDef(outerSym) };
else {
newVParamsI = new ValDef[vparams[0].length + 1];
newVParamsI[0] = gen.ValDef(outerSym);
System.arraycopy(vparams[0], 0, newVParamsI, 1, vparams[0].length);
}
ValDef[][] newVParams = new ValDef[][] { newVParamsI };
constSym.updateInfo(newConstType);
int newMods = classDef.mods | Modifiers.STATIC;
classSym.flags |= Modifiers.STATIC;
return copy.ClassDef(classDef,
newMods,
classDef.name,
transform(classDef.tparams),
transform(newVParams),
transform(classDef.tpe),
(Template)transform((Tree)classDef.impl));
}
// Return the number of outer links to follow to find the given
// symbol.
protected int outerLevel(Symbol sym) {
Iterator classIt = classStack.iterator();
for (int level = 0; classIt.hasNext(); ++level) {
Symbol classSym = (Symbol)classIt.next();
if (classSym == sym)
return level;
}
return -1;
}
// Return a tree referencing the "level"th outer class.
protected Tree outerRef(int level) {
assert level >= 0 : level;
if (level == 0) {
Symbol thisSym = (Symbol)classStack.getFirst();
return gen.This(thisSym.pos, thisSym);
} else {
Iterator outerIt = outerLinks.iterator();
Tree root = gen.Ident((Symbol)outerIt.next());
for (int l = 1; l < level; ++l) {
Symbol outerSym = (Symbol)outerIt.next();
root = gen.mkStable(gen.Select(root, outerSym));
}
return root;
}
}
public Tree transform(Tree tree) {
switch (tree) {
case ClassDef(int mods, _, _, _, _, _) : {
// Add outer link
ClassDef classDef = (ClassDef) tree;
Symbol sym = classDef.symbol();
Tree newTree;
classStack.addFirst(sym);
if (classStack.size() == 1 || Modifiers.Helper.isStatic(mods)) {
outerLinks.addFirst(null);
newTree = super.transform(tree);
} else
newTree = addOuterLink(classDef);
outerLinks.removeFirst();
classStack.removeFirst();
return newTree;
}
case Ident(Name name): {
if (! name.isTermName())
return super.transform(tree);
// Follow "outer" links to fetch data in outer classes.
int level = outerLevel(tree.symbol().classOwner());
if (level > 0) {
Tree root = outerRef(level);
return gen.mkStable(gen.Select(root, tree.symbol()));
} else {
return super.transform(tree);
}
}
case This(Tree qualifier): {
// If "this" refers to some outer class, replace it by
// explicit reference to it.
int level = qualifier.hasSymbol() ? outerLevel(qualifier.symbol()) : 0;
if (level > 0)
return outerRef(level);
else
return super.transform(tree);
}
case Apply(Tree fun, Tree[] args): {
// Add outer parameter to constructor calls.
Tree realFun;
Tree[] typeArgs;
switch (fun) {
case TypeApply(Tree fun2, Tree[] tArgs):
realFun = fun2; typeArgs = tArgs; break;
default:
realFun = fun; typeArgs = null; break;
}
Tree newFun = null, newArg = null;
if (realFun.hasSymbol() && realFun.symbol().isPrimaryConstructor()) {
switch (transform(realFun)) {
case Select(Tree qualifier, Name selector): {
if (! (qualifier.hasSymbol()
&& Modifiers.Helper.isNoVal(qualifier.symbol().flags))) {
newFun = make.Ident(qualifier.pos, selector)
.setType(realFun.type())
.setSymbol(realFun.symbol());
newArg = qualifier;
}
} break;
case Ident(Name name): {
int level = outerLevel(realFun.symbol().owner());
if (level >= 0) {
newFun = realFun;
newArg = outerRef(level);
}
} break;
default:
throw global.fail("unexpected node in constructor call");
}
if (newFun != null && newArg != null) {
Tree[] newArgs = new Tree[args.length + 1];
newArgs[0] = newArg;
System.arraycopy(args, 0, newArgs, 1, args.length);
Tree finalFun;
if (typeArgs != null)
finalFun = copy.TypeApply(fun, newFun, typeArgs);
else
finalFun = newFun;
finalFun.type = addValueParam(finalFun.type,
outerSym(realFun.symbol()));
return copy.Apply(tree, finalFun, transform(newArgs));
} else
return super.transform(tree);
} else
return super.transform(tree);
}
default:
return super.transform(tree);
}
}
}
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