/* NSC -- new Scala compiler
* Copyright 2005-2006 LAMP/EPFL
* @author Martin Odersky
*/
// $Id$
package scala.tools.nsc.transform
import symtab._
import Flags._
import scala.collection.mutable.{HashMap, ListBuffer}
import matching.{TransMatcher, PatternNodes, CodeFactory, PatternMatchers}
/** This class ...
*
* @author Martin Odersky
* @version 1.0
*/
abstract class ExplicitOuter extends InfoTransform with TransMatcher with PatternNodes with CodeFactory with PatternMatchers with TypingTransformers {
import global._
import definitions._
import posAssigner.atPos
/** The following flags may be set by this phase: */
override def phaseNewFlags: long = notPRIVATE | notPROTECTED
/** the name of the phase: */
val phaseName: String = "explicitouter"
/** This class does not change linearization */
override def changesBaseClasses = false
protected def newTransformer(unit: CompilationUnit): Transformer =
new ExplicitOuterTransformer(unit)
/** Is given <code>clazz</code> an inner class? */
private def isInner(clazz: Symbol) =
!clazz.isPackageClass && !clazz.outerClass.isStaticOwner
private def outerField(clazz: Symbol): Symbol = {
val result = clazz.info.member(nme.getterToLocal(nme.OUTER))
if (result == NoSymbol)
assert(false, "no outer field in "+clazz+clazz.info.decls+" at "+phase)
result
}
def outerAccessor(clazz: Symbol): Symbol = {
val firstTry = clazz.info.decl(clazz.expandedName(nme.OUTER))
if (firstTry != NoSymbol && firstTry.outerSource == clazz) firstTry
else {
var e = clazz.info.decls.elems
while (e != null && e.sym.outerSource != clazz) e = e.next
if (e != null) e.sym else NoSymbol
}
}
/** <p>
* The type transformation method:
* </p>
* <ol>
* <li>
* Add an outer parameter to the formal parameters of a constructor
* in a inner non-trait class;
* </li>
* <li>
* Add a protected $outer field to an inner class which is not a trait.
* </li>
* <li>
* <p>
* Add an outer accessor <code>$outer$$C</code> to every inner class
* with fully qualified name <code>C</code> that is not an interface.
* The outer accesssor is abstract for traits, concrete for other
* classes.
* </p>
* <p>
* 3a. Also add overriding accessor defs to every class that inherits
* mixin classes with outer accessor defs (unless the superclass
* already inherits the same mixin).
* </p>
* <li>
* <li>
* Add a mixin constructor <code>$init$</code> to all mixins except interfaces
* Leave all other types unchanged. todo: move to later
* </li>
* <li>
* Make all super accessors and modules in traits non-private, mangling
* their names.
* </li>
* <li>
* Remove protected flag from all members of traits.
* </li>
* </ol>
*/
def transformInfo(sym: Symbol, tp: Type): Type = tp match {
case MethodType(formals, restpe) =>
if (sym.owner.isTrait && ((sym hasFlag SUPERACCESSOR) || sym.isModule)) { // 5
sym.makeNotPrivate(sym.owner)
}
if (sym.owner.isTrait && (sym hasFlag PROTECTED)) sym setFlag notPROTECTED // 6
if (sym.isClassConstructor && isInner(sym.owner)) // 1
MethodType(sym.owner.outerClass.thisType :: formals, restpe)
else tp
case ClassInfoType(parents, decls, clazz) =>
var decls1 = decls
if (isInner(clazz) && !(clazz hasFlag INTERFACE)) {
decls1 = newScope(decls.toList)
val outerAcc = clazz.newMethod(clazz.pos, nme.OUTER) // 3
outerAcc.expandName(clazz)
val restpe = if (clazz.isTrait) clazz.outerClass.tpe else clazz.outerClass.thisType
decls1 enter clazz.newOuterAccessor(clazz.pos).setInfo(MethodType(List(), restpe))
if (!clazz.isTrait) // 2
//todo: avoid outer field if superclass has same outer value?
decls1 enter (
clazz.newValue(clazz.pos, nme.getterToLocal(nme.OUTER))
setFlag (SYNTHETIC | PROTECTED | PARAMACCESSOR)
setInfo clazz.outerClass.thisType)
}
if (!clazz.isTrait && !parents.isEmpty) {
for (val mc <- clazz.mixinClasses) {
val mixinOuterAcc: Symbol = atPhase(phase.next)(outerAccessor(mc))
if (mixinOuterAcc != NoSymbol) {
if (decls1 eq decls) decls1 = newScope(decls.toList)
val newAcc = mixinOuterAcc.cloneSymbol(clazz)
newAcc.resetFlag(DEFERRED)
newAcc.setInfo(clazz.thisType.memberType(mixinOuterAcc))
decls1 enter newAcc
}
}
}
if (decls1 eq decls) tp else ClassInfoType(parents, decls1, clazz)
case PolyType(tparams, restp) =>
val restp1 = transformInfo(sym, restp)
if (restp eq restp1) tp else PolyType(tparams, restp1)
case _ =>
tp
}
/** A base class for transformers that maintain <code>outerParam</code>
* values for outer parameters of constructors.
* The class provides methods for referencing via outer.
*/
abstract class OuterPathTransformer(unit: CompilationUnit) extends TypingTransformer(unit) {
/** The directly enclosing outer parameter, if we are in a constructor */
protected var outerParam: Symbol = NoSymbol
/** The first outer selection from currently transformed tree.
* The result is typed but not positioned.
*/
protected def outerValue: Tree =
if (outerParam != NoSymbol) gen.mkAttributedIdent(outerParam)
else outerSelect(gen.mkAttributedThis(currentClass))
/** Select and apply outer accessor from 'base'
* The result is typed but not positioned.
*/
private def outerSelect(base: Tree): Tree =
localTyper.typed(Apply(Select(base, outerAccessor(base.tpe.symbol)), List()))
/** The path
* <blockquote><pre>`base'.$outer$$C1 ... .$outer$$Cn</pre></blockquote>
* which refers to the outer instance of class <code>to</code> of
* value <code>base</code>. The result is typed but not positioned.
*
* @param base ...
* @param from ...
* @param to ...
* @return ...
*/
protected def outerPath(base: Tree, from: Symbol, to: Symbol): Tree = {
//Console.println("outerPath from "+from+" to "+to+" at "+base+":"+base.tpe)
//assert(base.tpe.widen.baseType(from.toInterface) != NoType, ""+base.tpe.widen+" "+from.toInterface)//DEBUG
if (from == to || from.isImplClass && from.toInterface == to) base
else outerPath(outerSelect(base), from.outerClass, to)
}
override def transform(tree: Tree): Tree = {
val savedOuterParam = outerParam
try {
tree match {
case Template(_, _) =>
outerParam = NoSymbol
case DefDef(_, _, _, vparamss, _, _) =>
if (tree.symbol.isClassConstructor && isInner(tree.symbol.owner)) {
outerParam = vparamss.head.head.symbol
assert(outerParam.name == nme.OUTER)
}
case _ =>
}
super.transform(tree)
} catch {//debug
case ex: Throwable =>
System.out.println("exception when transforming " + tree)
throw ex
} finally {
outerParam = savedOuterParam
}
}
}
/** The phase performs the following transformations on terms:
* 1. An class which is not an interface and is not static gets an outer accessor
* (@see outerDefs)
* 1a. A class which is not a trait gets an outer field.
* 2. A mixin which is not also an interface gets a mixin constructor
* (@see mixinConstructorDef)
* 3. Constructor bodies are augmented by calls to supermixin constructors
* (@see addMixinConstructorCalls)
* 4. A constructor of a non-trait inner class gets an outer parameter.
* 5. A reference C.this where C refers to an outer class is replaced by a selection
* this.$outer$$C1 ... .$outer$$Cn (@see outerPath)
* 7. A call to a constructor Q.<init>(args) or Q.$init$(args) where Q != this and
* the constructor belongs to a non-static class is augmented by an outer argument.
* E.g. Q.<init>(OUTER, args) where OUTER is the qualifier corresponding to the
* singleton type Q.
* 8. A call to a constructor this.<init>(args) in a secondary constructor
* is augmented to this.<init>(OUTER, args) where OUTER is the last parameter
* of the secondary constructor.
* 9. Remove `private' modifier from class members M that are accessed from an inner class.
* 10.Remove `protected' modifier from class members M that are accessed
* without a super qualifier accessed from an inner class or trait.
* 11. Remove `private' and `protected' modifiers from type symbols
* 12. Remove `private' modifiers from members of traits
* Note: The whole transform is run in phase explicitOuter.next
*/
class ExplicitOuterTransformer(unit: CompilationUnit) extends OuterPathTransformer(unit) {
/** The definition tree of the outer accessor of current class
*/
def outerFieldDef: Tree = {
val outerF = outerField(currentClass)
ValDef(outerF, EmptyTree)
}
/** The definition tree of the outer accessor of current class
*/
def outerAccessorDef: Tree = {
val outerAcc = outerAccessor(currentClass)
var rhs = if (outerAcc hasFlag DEFERRED) EmptyTree
else Select(This(currentClass), outerField(currentClass))
localTyper.typed {
atPos(currentClass.pos) {
DefDef(outerAcc, vparamss => rhs)
}
}
}
/** The definition tree of the outer accessor for class `mixinClass'
* @param mixinClass The mixin class which defines the abstract outer accessor which is
* implemented by the generated one.
* @pre mixinClass is an inner class
*/
def mixinOuterAccessorDef(mixinClass: Symbol): Tree = {
val outerAcc = outerAccessor(mixinClass).overridingSymbol(currentClass)
if (outerAcc == NoSymbol)
Console.println("cc " + currentClass + ":" + currentClass.info.decls +
" at " + phase)//debug
assert(outerAcc != NoSymbol)
val path = gen.mkAttributedQualifier(currentClass.thisType.baseType(mixinClass).prefix)
val rhs = ExplicitOuterTransformer.this.transform(path)
localTyper.typed {
atPos(currentClass.pos) {
DefDef(outerAcc, vparamss => rhs)
}
}
}
/** The main transformation method */
override def transform(tree: Tree): Tree = {
val sym = tree.symbol
if (sym != null && sym.isType) {//(9)
if (sym hasFlag PRIVATE) sym setFlag notPRIVATE
if (sym hasFlag PROTECTED) sym setFlag notPROTECTED
}
tree match {
case Template(parents, decls) =>
val newDefs = new ListBuffer[Tree]
atOwner(tree, currentOwner) {
if (!(currentClass hasFlag INTERFACE) || (currentClass hasFlag lateINTERFACE)) {
if (isInner(currentClass)) {
if (!currentClass.isTrait) newDefs += outerFieldDef // (1a)
newDefs += outerAccessorDef // (1)
}
if (!currentClass.isTrait)
for (val mc <- currentClass.mixinClasses)
if (outerAccessor(mc) != NoSymbol)
newDefs += mixinOuterAccessorDef(mc)
}
}
super.transform(
copy.Template(tree, parents, if (newDefs.isEmpty) decls else decls ::: newDefs.toList))
case DefDef(mods, name, tparams, vparamss, tpt, rhs) =>
if (sym.isClassConstructor) {
rhs match {
case Literal(_) =>
// replace unit rhs () by empty block {()}
val rhs1 = Block(List(), rhs) setPos rhs.pos setType rhs.tpe
transform(copy.DefDef(tree, mods, name, tparams, vparamss, tpt, rhs1))
case _ =>
val clazz = sym.owner
val vparamss1 =
if (isInner(clazz)) { // (4)
val outerParam =
sym.newValueParameter(sym.pos, nme.OUTER) setInfo outerField(clazz).info
((ValDef(outerParam) setType NoType) :: vparamss.head) :: vparamss.tail
} else vparamss
super.transform(copy.DefDef(tree, mods, name, tparams, vparamss1, tpt, rhs))
}
} else { //todo: see whether we can move this to transformInfo
if (sym.owner.isTrait && (sym hasFlag (ACCESSOR | SUPERACCESSOR)))
sym.makeNotPrivate(sym.owner); //(2)
super.transform(tree)
}
case This(qual) =>
if (sym == currentClass || (sym hasFlag MODULE) && sym.isStatic) tree
else atPos(tree.pos)(outerPath(outerValue, currentClass.outerClass, sym)) // (5)
case Select(qual, name) =>
if (currentClass != sym.owner && currentClass != sym.moduleClass) // (3)
sym.makeNotPrivate(sym.owner)
val qsym = qual.tpe.widen.symbol
if ((sym hasFlag PROTECTED) && //(4)
(qsym.isTrait || !(qual.isInstanceOf[Super] || (qsym isSubClass currentClass))))
sym setFlag notPROTECTED
super.transform(tree)
case Apply(sel @ Select(qual, name), args)
if (name == nme.CONSTRUCTOR && isInner(sel.symbol.owner)) =>
val outerVal = atPos(tree.pos) {
if (qual.isInstanceOf[This]) { // it's a call between constructors of same class
assert(outerParam != NoSymbol)
outerValue
} else {
var pre = qual.tpe.prefix
if (pre == NoPrefix) pre = sym.owner.outerClass.thisType
gen.mkAttributedQualifier(pre)
}
}
super.transform(copy.Apply(tree, sel, outerVal :: args))
case Match(selector, cases) => // <----- transmatch hook
val tid = if (settings.debug.value) {
val q = unit.fresh.newName("tidmark")
Console.println("transforming patmat with tidmark "+q+" ncases = "+cases.length)
q
} else null
if ((cases.length > 1) && (treeInfo.isDefaultCase(cases(0))))
assert(false,"transforming too much, " + tid)
val nselector = transform(selector)
assert(nselector.tpe =:= selector.tpe)
val ncases = transformCaseDefs(cases)
ExplicitOuter.this.resultType = tree.tpe
//Console.println("TransMatcher currentOwner ="+currentOwner+")")
//Console.println("TransMatcher selector.tpe ="+selector.tpe+")")
//Console.println("TransMatcher resultType ="+resultType+")")
val t_untyped = handlePattern(nselector, ncases, currentOwner, transform)
//Console.println("t_untyped "+t_untyped.toString())
val t = atPos(tree.pos) { localTyper.typed(t_untyped, resultType) }
//t = transform(t)
//val t = atPos(tree.pos) { typed(t_untyped, resultType) }
//val t = atPos(tree.pos) { typed(t_untyped) }
//Console.println("t typed "+t.toString())
if (settings.debug.value)
Console.println("finished translation of " + tid)
t
case _ =>
super.transform(tree)
}
}
/** The transformation method for whole compilation units */
override def transformUnit(unit: CompilationUnit): unit = {
cunit = unit
atPhase(phase.next) { super.transformUnit(unit) }
}
}
}