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/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
\* */
// $Id$
package scalac.transformer;
import java.util.Collections;
import java.util.Map;
import java.util.HashMap;
import java.util.Iterator;
import scalac.Global;
import scalac.Phase;
import scalac.PhaseDescriptor;
import scalac.CompilationUnit;
import scalac.ast.GenTransformer;
import scalac.ast.Tree;
import scalac.ast.Tree.Ident;
import scalac.ast.Tree.Template;
import scalac.symtab.Modifiers;
import scalac.symtab.Scope;
import scalac.symtab.Symbol;
import scalac.symtab.Type;
import scalac.util.Debug;
import scalac.util.Name;
import scalac.util.Names;
/**
* This phase does the following:
*
* - In every nested class, adds to each of its constructor a new
* value parameter that contains a link to the outer class.
*
* - In every nested type, adds to each of its constructor a new type
* parameter for every type parameter appearing in outer types.
*
* - In every class, adds a forwarding "super" method for every method
* that is accessed via "super" in a nested class.
*
* - Replaces all prefixes of TypeRefs by localThisTypes.
*
* - Adds all missing qualifiers.
*/
// !!! needs to be cleaned
public class ExplicitOuterClassesPhase extends Phase {
//########################################################################
// Private Fields
/** A map from constructor symbols to type transformers */
private final Map/*<Symbol,TypeTransformer>*/ transformers = new HashMap();
//########################################################################
// Public Constructors
/** Initializes this instance. */
public ExplicitOuterClassesPhase(Global global,PhaseDescriptor descriptor){
super(global, descriptor);
}
//########################################################################
// Public Methods
/** Applies this phase to the given compilation units. */
public void apply(CompilationUnit[] units) {
treeTransformer.apply(units);
}
/** Applies this phase to the given type for the given symbol. */
public Type transformInfo(Symbol symbol, Type type) {
if (symbol.isConstructor()) {
Symbol clasz = symbol.constructorClass();
if (clasz.isClass() && !clasz.isCompoundSym())
return transformInfo(clasz, symbol, type);
}
return getTypeTransformerFor(symbol).apply(type);
}
//########################################################################
// Private Methods
/**
* Computes and returns the new type of the constructor. As a side
* effect, creates and stores the type transformer corresponding
* to this constructor.
*/
private Type transformInfo(Symbol clasz, Symbol constructor, Type type) {
Symbol[] tparams = type.typeParams();
Symbol[] vparams = type.valueParams();
int depth = getClassDepth(clasz);
Map/*<Symbol,Type>*/ table = new HashMap();
table.put(clasz, clasz.thisType());
for (int i = 0; i < tparams.length; i++)
table.put(tparams[i], tparams[i].type());
Symbol[] owners = new Symbol[depth];
Symbol[][] tparamss = new Symbol[depth][];
Symbol vlink = null;
if (depth > 0) {
int count = depth;
Symbol owner = clasz.owner();
for (int i = depth - 1; i >= 0; i--) {
owners[i] = owner;
tparamss[i] = owner.typeParams();
count += tparamss[i].length;
owner = owner.owner();
}
// create outer value link
vparams = Symbol.cloneArray(1, vparams);
int vflags = Modifiers.SYNTHETIC;
Name vname = Names.OUTER(constructor);
vlink = constructor.newVParam(constructor.pos, vflags, vname);
vlink.setInfo(clasz.owner().thisType());
vparams[0] = vlink;
int o = 0;
tparams = Symbol.cloneArray(count, tparams);
for (int i = 0; i < depth; i++) {
// create new type parameters
for (int j = 0; j < tparamss[i].length; j++) {
Symbol oldtparam = tparamss[i][j];
Symbol newtparam = oldtparam.cloneSymbol(constructor);
newtparam.name = Names.OUTER(constructor, oldtparam);
table.put(oldtparam, newtparam.type());
tparams[o++] = newtparam;
}
// create outer type links
int tflags = Modifiers.PARAM | Modifiers.COVARIANT | Modifiers.SYNTHETIC | Modifiers.STABLE;
Name tname = Names.OUTER(constructor, owners[i]);
Symbol tlink = constructor.newTParam(
constructor.pos, tflags, tname, owners[i].typeOfThis());
table.put(owners[i], tlink.type());
tparams[o++] = tlink;
}
}
transformers.put(constructor, new TypeTransformer(table));
type = Type.typeRef(Type.NoPrefix, clasz, Symbol.type(tparams));
type = Type.MethodType(vparams, type);
if (tparams.length > 0) type = Type.PolyType(tparams, type);
return type;
}
/** Returns the type transformer for the given symbol. */
private TypeTransformer getTypeTransformerFor(Symbol symbol) {
while (true) {
Symbol test = symbol;
if (test.isConstructor()) test = test.constructorClass();
// !!! isClassType -> isClass ?
if (test.isClassType() && !test.isCompoundSym()) break;
symbol = symbol.owner();
}
// !!!
// while (!symbol.isClassType() && !(symbol.isConstructor() && symbol.constructorClass().isClassType())) // !!! isClassType -> isClass ?
// symbol = symbol.owner();
if (symbol.isClassType())
symbol = symbol.primaryConstructor();
if (symbol.constructorClass().isPackageClass())
return topLevelTypeTransformer;
TypeTransformer context = (TypeTransformer)transformers.get(symbol);
if (context == null) {
symbol.nextInfo();
context = (TypeTransformer)transformers.get(symbol);
assert context != null: Debug.show(symbol);
}
return context;
}
//########################################################################
// Private Functions
/**
* Returns the depth of the specified class. The depth of a class
* is:
* - -1 for a package class
* - 0 for a top-level class
* - the depth of the enclosing class plus 1 for an inner class
*/
private static int getClassDepth(Symbol clasz) {
assert clasz.isClass() || clasz.isPackageClass(): Debug.show(clasz);
int depth = -1;
while (!clasz.isPackageClass()) { clasz = clasz.owner(); depth++; }
return depth;
}
/**
* Returns the type arguments of the flattened version of the
* specified type reference. This functions takes and returns
* non-transformed types.
*/
private static Type[] getFlatArgs(Type prefix, Symbol clasz, Type[] args) {
int depth = getClassDepth(clasz);
if (depth <= 0) return args;
Type[] prefixes = new Type[depth];
Type[][] argss = new Type[depth][];
int count = collect(prefix, clasz, prefixes, argss);
args = Type.cloneArray(count, args);
for (int i = 0, o = 0; i < depth; i++) {
for (int j = 0; j < argss[i].length; j++)
args[o++] = argss[i][j];
args[o++] = prefixes[i];
}
return args;
}
// where
private static int collect(Type prefix, Symbol clasz, Type[] prefixes,
Type[][] argss)
{
int count = prefixes.length;
for (int i = prefixes.length - 1; i >= 0; i--) {
prefixes[i] = prefix;
Symbol owner = clasz.owner();
Type base = prefix.baseType(owner);
switch (base) {
case TypeRef(Type type, Symbol symbol, Type[] args):
assert symbol == owner: Debug.show(base);
count += args.length;
argss[i] = args;
prefix = type;
clasz = owner;
continue;
default:
throw Debug.abortIllegalCase(base);
}
}
return count;
}
//########################################################################
// Private Class - Type transformer
/** The type transformer for top-level types */
private static final TypeTransformer topLevelTypeTransformer =
new TypeTransformer(Collections.EMPTY_MAP);
/** The type transformer */
private static final class TypeTransformer extends Type.MapOnlyTypes {
private final Map/*<Symbol,Type>*/ tparams;
public TypeTransformer(Map tparams) {
this.tparams = tparams;
}
public Type apply(Type type) {
switch (type) {
case TypeRef(Type prefix, Symbol symbol, Type[] args):
if (symbol.isParameter() && symbol.owner().isConstructor()) {
assert prefix == Type.NoPrefix: type;
assert args.length == 0: type;
Object value = tparams.get(symbol);
return value != null ? (Type)value : type;
}
if (symbol.isClass() && !symbol.isCompoundSym()) {
args = map(getFlatArgs(prefix, symbol, args));
prefix = Type.NoPrefix;
return Type.typeRef(prefix, symbol, args);
}
if (symbol.isPackageClass()) {
args = Type.EMPTY_ARRAY;
prefix = Type.NoPrefix;
return Type.typeRef(prefix, symbol, args);
}
return Type.typeRef(apply(prefix), symbol, map(args));
case SingleType(Type prefix, Symbol symbol):
if (symbol.owner().isPackageClass())
return Type.singleType(Type.NoPrefix, symbol);
return Type.singleType(apply(prefix), symbol);
case ThisType(Symbol clasz):
Object value = tparams.get(clasz);
if (value != null) return (Type)value;
assert clasz.isCompoundSym() || clasz.isPackageClass():
Debug.show(clasz);
return type;
case CompoundType(Type[] parents, Scope members):
// !!! this case should not be needed
return Type.compoundType(map(parents), members, type.symbol());
default:
return map(type);
}
}
}
//########################################################################
// Private Class - Tree transformer
/** The tree transformer */
private final GenTransformer treeTransformer = new GenTransformer(global) {
/** The current context */
private Context context;
/** The current method */
private Symbol method;
/** Transforms the given type. */
public Type transform(Type type) {
return context.transformer.apply(type);
}
/** Transforms the given tree. */
public Tree transform(Tree tree) {
if (global.debug) global.log("transforming " + tree);//debug
switch (tree) {
case ClassDef(_, _, _, _, _, Template impl):
Symbol clasz = tree.symbol();
context = new Context(context, clasz, new HashMap(), new HashMap());
Tree[] parents = transform(impl.parents);
Tree[] body = transform(impl.body);
body = Tree.concat(body, genAccessMethods(false));
body = Tree.concat(body, genAccessMethods(true));
if (context.vfield != null) {
body = Tree.cloneArray(1, body);
body[0] = gen.ValDef(
context.vfield,
gen.Ident(context.vfield.pos, context.vparam));
}
context = context.outer;
return gen.ClassDef(clasz, parents, impl.symbol(), body);
case DefDef(_, _, _, _, _, Tree rhs):
Symbol method = tree.symbol();
Context backup = context;
if (method.isConstructor())
context = context.getConstructorContext(method);
this.method = method;
rhs = transform(rhs);
this.method = null;
context = backup;
return gen.DefDef(method, rhs);
case Apply(Tree vfun, Tree[] vargs):
switch (vfun) {
case TypeApply(Tree tfun, Tree[] targs):
if (!tfun.symbol().isConstructor()) break;
return transform(tree, vargs, vfun, targs, tfun);
default:
if (!vfun.symbol().isConstructor()) break;
return transform(tree, vargs, vfun, Tree.EMPTY_ARRAY,vfun);
}
return super.transform(tree);
case This(_):
return genOuterRef(tree.pos, tree.symbol());
case Select(Tree qualifier, _):
Symbol symbol = tree.symbol();
if (symbol.owner().isStaticOwner()) // !!! qualifier ignored
return gen.mkGlobalRef(tree.pos, symbol);
Symbol access;
switch (qualifier) {
case Super(_, _):
Symbol clasz = qualifier.symbol();
if (clasz == context.clasz) {
access = symbol;
qualifier = gen.Super(tree.pos, qualifier.symbol());
} else {
access = getAccessSymbol(symbol, clasz);
qualifier = genOuterRef(qualifier.pos, clasz);
}
break;
default:
access = getAccessSymbol(symbol, null);
qualifier = transform(qualifier);
break;
}
tree = gen.Select(tree.pos, qualifier, access);
if (access != symbol && !symbol.isMethod())
tree = gen.mkApply__(tree);
return tree;
default:
return super.transform(tree);
}
}
/* Add outer type and value arguments to constructor calls. */
private Tree transform(Tree vapply, Tree[] vargs, Tree tapply,
Tree[] targs, Tree tree)
{
switch (tree) {
case Select(Tree qualifier, _):
Symbol symbol = tree.symbol();
Symbol clasz = symbol.constructorClass();
if (getClassDepth(clasz) > 0) {
Type[] types = Tree.typeOf(targs);
types = getFlatArgs(qualifier.type(), clasz, types);
targs = gen.mkTypes(tapply.pos, types);
vargs = Tree.cloneArray(1, vargs);
vargs[0] = qualifier;
} else {
assert !containsValue(qualifier): tree;
}
tree = gen.Ident(tree.pos, symbol);
if (targs.length != 0)
tree = gen.TypeApply(tapply.pos, tree, transform(targs));
return gen.Apply(vapply.pos, tree, transform(vargs));
default:
throw Debug.abortIllegalCase(tree);
}
}
/**
* Returns the symbol to access the specified member from the
* current context. If "svper" is non null, the member is
* selected from the superclass of the specified class. The
* returned symbol may be the same as the given one.
*/
private Symbol getAccessSymbol(Symbol member, Symbol svper) {
if (member.isPublic() && svper == null) return member;
Context context = this.context;
for (; context != null; context = context.outer)
if (svper != null
? context.clasz == svper
: member.isPrivate()
? context.clasz == member.owner()
// !!! This is incorrect without static access methods
: context.clasz.isSubClass(member.owner())) break;
assert context != null: Debug.show(this.context, member);
if (context == this.context) return member;
Map table = svper != null ? context.supers : context.selfs;
Symbol access = (Symbol)table.get(member);
if (access == null) {
// !!! generate static access methods ?
Name name = Names.ACCESS(member, svper != null);
access = context.clasz.newAccessMethod(context.clasz.pos,name);
global.nextPhase();
Type info = member.isMethod()
? member.info().cloneType(member, access)
: Type.MethodType(Symbol.EMPTY_ARRAY, member.info());
access.setInfo(info);
global.prevPhase();
table.put(member, access);
context.clasz.nextInfo().members().enter(access);
assert Debug.log("created access method: ", access);
}
return access;
}
/** Generates the trees of the access methods. */
private Tree[] genAccessMethods(boolean withSuper) {
Map table = withSuper ? context.supers : context.selfs;
if (table.size() == 0) return Tree.EMPTY_ARRAY;
Tree[] trees = new Tree[table.size()];
Iterator entries = table.entrySet().iterator();
for (int i = 0; i < trees.length; i++) {
Map.Entry entry = (Map.Entry)entries.next();
Symbol member = (Symbol)entry.getKey();
Symbol access = (Symbol)entry.getValue();
int pos = access.pos;
Tree qualifier = withSuper
? gen.Super(pos, context.clasz)
: gen.This(pos, context.clasz);
Tree select = gen.Select(qualifier, member);
Tree[] targs = gen.mkTypeRefs(pos, access.nextTypeParams());
Tree[] vargs = gen.mkLocalRefs(pos, access.nextValueParams());
Tree body = member.isMethod()
? gen.mkApplyTV(select, targs, vargs)
: select;
trees[i] = gen.DefDef(access, body);
}
return trees;
}
/** Returns a tree referencing the given outer class. */
private Tree genOuterRef(int pos, Symbol clasz) {
if (context.clasz == clasz) return gen.This(pos, clasz);
Tree tree = method == null || method.isConstructor()
? gen.Ident(pos, context.vparam)
: gen.Select(gen.This(pos, context.clasz),context.getVField());
for (Context c = context.outer;; c = c.outer) {
assert c != null: Debug.show(clasz, context.clasz);
if (c.clasz == clasz) return tree;
Symbol access = getAccessSymbol(c.getVField(), null);
tree = gen.Apply(gen.Select(tree, access));
}
}
/** Tests whether the tree contains some value computation. */
private boolean containsValue(Tree tree) {
switch (tree) {
case This(_):
return !tree.symbol().isPackageClass();
case Select(Tree qualifier, _):
return containsValue(qualifier) || tree.symbol().isValue();
default:
return false;
}
}
};
//########################################################################
// Private Class - Tree transformer context
/** This class represents the tree transformation context. */
private class Context {
/** The outer context */
public final Context outer;
/** The context class */
public final Symbol clasz;
/** The context type transformer */
public final TypeTransformer transformer;
/** The self access methods (maps members to accessors) */
public final Map/*<Symbol,Symbol>*/ selfs;
/** The super access methods (maps members to accessors) */
public final Map/*<Symbol,Symbol>*/ supers;
/** The context outer paramater (null if none) */
public final Symbol vparam;
/** The context outer field (null if none or not yet used) */
private Symbol vfield;
/** Initializes this instance. */
public Context(Context outer, Symbol symbol, Map selfs, Map supers) {
this.outer = outer;
this.clasz = symbol.constructorClass();
this.transformer = getTypeTransformerFor(symbol);
this.selfs = selfs;
this.supers = supers;
this.vparam = outer != null ? symbol.nextValueParams()[0] : null;
}
/** Returns a context for the given constructor. */
public Context getConstructorContext(Symbol constructor) {
assert constructor.constructorClass() == clasz;
return new Context(outer, constructor, selfs, supers);
}
/**
* Returns the outer value field. The field is created on the
* fly if it does not yet exist.
*/
private Symbol getVField() {
assert outer != null: Debug.show(clasz);
if (vfield == null) {
int flags =
Modifiers.SYNTHETIC | Modifiers.PRIVATE | Modifiers.STABLE;
vfield = clasz.newField(clasz.pos, flags, Names.OUTER(clasz));
vfield.setInfo(outer.clasz.thisType());
clasz.members().enterNoHide(vfield);
}
return vfield;
}
}
//########################################################################
}
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