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|
/* NSC -- new Scala compiler
* Copyright 2005-2009 LAMP/EPFL
* @author Martin Odersky
*/
// $Id$
package scala.tools.nsc.typechecker
import symtab.Flags._
import scala.collection.mutable.ListBuffer
/** <ul>
* <li>
* <code>productArity</code>, <code>element</code> implementations added
* to case classes
* </li>
* <li>
* <code>equals</code>, <code>hashCode</code> and </code>toString</code>
* methods are added to case classes, unless they are defined in the
* class or a baseclass different from <code>java.lang.Object</code>
* </li>
* <li>
* <code>toString</code> method is added to case objects, unless they
* are defined in the class or a baseclass different from
* <code>java.lang.Object</code>
* </li>
* </ul>
*/
trait SyntheticMethods { self: Analyzer =>
import global._ // the global environment
import definitions._ // standard classes and methods
//import global.typer.{typed} // methods to type trees
// @S: type hack: by default, we are used from global.analyzer context
// so this cast won't fail. If we aren't in global.analyzer, we have
// to override this method anyways.
protected def typer : Typer = global.typer.asInstanceOf[Typer]
/**
* @param templ ...
* @param clazz ...
* @param unit ...
* @return ...
*/
def addSyntheticMethods(templ: Template, clazz: Symbol, context: Context): Template = try {
val localContext = if (reporter.hasErrors) context.makeSilent(false) else context
val localTyper = newTyper(localContext)
def hasImplementation(name: Name): Boolean = {
val sym = clazz.info.member(name) // member and not nonPrivateMember: bug #1385
sym.isTerm && !(sym hasFlag DEFERRED)
}
def hasOverridingImplementation(meth: Symbol): Boolean = {
val sym = clazz.info.nonPrivateMember(meth.name)
sym.alternatives exists { sym =>
sym != meth && !(sym hasFlag DEFERRED) && !(sym hasFlag (SYNTHETIC | SYNTHETICMETH)) &&
(clazz.thisType.memberType(sym) matches clazz.thisType.memberType(meth))
}
}
def syntheticMethod(name: Name, flags: Int, tpe: Type) =
newSyntheticMethod(name, flags | OVERRIDE, tpe)
def newSyntheticMethod(name: Name, flags: Int, tpe: Type) = {
var method = clazz.newMethod(clazz.pos, name)
.setFlag(flags | SYNTHETICMETH)
.setInfo(tpe)
method = clazz.info.decls.enter(method).asInstanceOf[TermSymbol]
method
}
/*
def productSelectorMethod(n: int, accessor: Symbol): Tree = {
val method = syntheticMethod(newTermName("_"+n), FINAL, accessor.tpe)
typed(DefDef(method, vparamss => gen.mkAttributedRef(accessor)))
}
*/
def productPrefixMethod: Tree = {
val method = syntheticMethod(nme.productPrefix, 0, PolyType(List(), StringClass.tpe))
typer.typed(DefDef(method, vparamss => Literal(Constant(clazz.name.decode))))
}
def productArityMethod(nargs:Int ): Tree = {
val method = syntheticMethod(nme.productArity, 0, PolyType(List(), IntClass.tpe))
typer.typed(DefDef(method, vparamss => Literal(Constant(nargs))))
}
def productElementMethod(accs: List[Symbol]): Tree = {
//val retTpe = lub(accs map (_.tpe.resultType))
val method = syntheticMethod(nme.productElement, 0, MethodType(List(IntClass.tpe), AnyClass.tpe/*retTpe*/))
typer.typed(DefDef(method, vparamss => Match(Ident(vparamss.head.head), {
(for ((sym,i) <- accs.zipWithIndex) yield {
CaseDef(Literal(Constant(i)),EmptyTree, Ident(sym))
}):::List(CaseDef(Ident(nme.WILDCARD), EmptyTree,
Throw(New(TypeTree(IndexOutOfBoundsExceptionClass.tpe), List(List(
Select(Ident(vparamss.head.head), nme.toString_)
))))))
})))
}
def moduleToStringMethod: Tree = {
val method = syntheticMethod(nme.toString_, FINAL, MethodType(List(), StringClass.tpe))
typer.typed(DefDef(method, vparamss => Literal(Constant(clazz.name.decode))))
}
def forwardingMethod(name: Name): Tree = {
val target = getMember(ScalaRunTimeModule, "_" + name)
val paramtypes =
if (target.tpe.paramTypes.isEmpty) List()
else target.tpe.paramTypes.tail
val method = syntheticMethod(
name, 0, MethodType(paramtypes, target.tpe.resultType))
typer.typed(DefDef(method, vparamss =>
Apply(gen.mkAttributedRef(target), This(clazz) :: (vparamss.head map Ident))))
}
def equalsSym =
syntheticMethod(nme.equals_, 0, MethodType(List(AnyClass.tpe), BooleanClass.tpe))
/** The equality method for case modules:
* def equals(that: Any) = this eq that
*/
def equalsModuleMethod: Tree = {
val method = equalsSym
val methodDef =
DefDef(method, vparamss =>
Apply(
Select(This(clazz), Object_eq),
List(
TypeApply(
Select(
Ident(vparamss.head.head),
Any_asInstanceOf),
List(TypeTree(AnyRefClass.tpe))))))
localTyper.typed(methodDef)
}
/** The equality method for case classes:
* def equals(that: Any) =
* that.isInstanceOf[AnyRef] &&
* ((this eq that.asInstanceOf[AnyRef]) ||
* (that match {
* case this.C(this.arg_1, ..., this.arg_n) => true
* case _ => false
* }))
*/
def equalsClassMethod: Tree = {
val method = equalsSym
val methodDef =
DefDef(
method,
{ vparamss =>
val that = Ident(vparamss.head.head)
val constrParamTypes = clazz.primaryConstructor.tpe.paramTypes
val hasVarArgs = !constrParamTypes.isEmpty && constrParamTypes.last.typeSymbol == RepeatedParamClass
if (false && clazz.isStatic) {
// todo: elim
val target = getMember(ScalaRunTimeModule, if (hasVarArgs) nme._equalsWithVarArgs else nme._equals)
Apply(
Select(
TypeApply(
Select(that, Any_isInstanceOf),
List(TypeTree(clazz.tpe))),
Boolean_and),
List(
Apply(gen.mkAttributedRef(target),
This(clazz) :: (vparamss.head map Ident))))
} else {
val (pat, guard) = {
val guards = new ListBuffer[Tree]
val params = for ((acc, cpt) <- clazz.caseFieldAccessors zip constrParamTypes) yield {
val name = context.unit.fresh.newName(clazz.pos, acc.name+"$")
val isVarArg = cpt.typeSymbol == RepeatedParamClass
guards += Apply(
Select(
Ident(name),
if (isVarArg) nme.sameElements else nme.EQ),
List(Ident(acc)))
Bind(name,
if (isVarArg) Star(Ident(nme.WILDCARD))
else Ident(nme.WILDCARD))
}
( Apply(Ident(clazz.name.toTermName), params),
if (guards.isEmpty) EmptyTree
else guards reduceLeft { (g1: Tree, g2: Tree) =>
Apply(Select(g1, nme.AMPAMP), List(g2))
}
)
}
val isAnyRef = TypeApply(
Select(that, Any_isInstanceOf),
List(TypeTree(AnyRefClass.tpe)))
val cast = TypeApply(
Select(that, Any_asInstanceOf),
List(TypeTree(AnyRefClass.tpe)))
val eq_ = Apply(Select( This(clazz) , nme.eq), List(that setType AnyRefClass.tpe))
val match_ = Match(that, List(
CaseDef(pat, guard, Literal(Constant(true))),
CaseDef(Ident(nme.WILDCARD), EmptyTree, Literal(Constant(false)))))
Apply(
Select(isAnyRef, Boolean_and),
List(Apply(Select(eq_, Boolean_or),
List(match_))))
}
}
)
localTyper.typed(methodDef)
}
def hasSerializableAnnotation(clazz: Symbol): Boolean =
!clazz.getAttributes(definitions.SerializableAttr).isEmpty
def readResolveMethod: Tree = {
// !!! the synthetic method "readResolve" should be private,
// but then it is renamed !!!
val method = newSyntheticMethod(nme.readResolve, PROTECTED,
MethodType(List(), ObjectClass.tpe))
typer.typed(DefDef(method, vparamss => gen.mkAttributedRef(clazz.sourceModule)))
}
def newAccessorMethod(tree: Tree): Tree = tree match {
case DefDef(_, _, _, _, _, rhs) =>
var newAcc = tree.symbol.cloneSymbol
newAcc.name = context.unit.fresh.newName(tree.symbol.pos, tree.symbol.name + "$")
newAcc.setFlag(SYNTHETIC).resetFlag(ACCESSOR | PARAMACCESSOR | PRIVATE)
newAcc = newAcc.owner.info.decls enter newAcc
val result = typer.typed(DefDef(newAcc, vparamss => rhs.duplicate))
log("new accessor method " + result)
result
}
def beanSetterOrGetter(sym: Symbol): Symbol =
if (!sym.name(0).isLetter) {
context.unit.error(sym.pos, "attribute `BeanProperty' can be applied only to fields that start with a letter")
NoSymbol
} else {
var name0 = sym.name
if (sym.isSetter) name0 = nme.setterToGetter(name0)
val prefix = if (sym.isSetter) "set" else
if (sym.tpe.resultType == BooleanClass.tpe) "is" else "get"
val arity = if (sym.isSetter) 1 else 0
val name1 = prefix + name0(0).toUpperCase + name0.subName(1, name0.length)
val sym1 = clazz.info.decl(name1)
if (sym1 != NoSymbol && sym1.tpe.paramTypes.length == arity) {
context.unit.error(sym.pos, "a definition of `"+name1+"' already exists in " + clazz)
NoSymbol
} else {
clazz.newMethod(sym.pos, name1)
.setInfo(sym.info)
.setFlag(sym.getFlag(DEFERRED | OVERRIDE | STATIC))
}
}
val ts = new ListBuffer[Tree]
def addBeanGetterMethod(sym: Symbol) = {
val getter = beanSetterOrGetter(sym)
if (getter != NoSymbol) {
clazz.info.decls.enter(getter)
ts += typer.typed(DefDef(
getter,
vparamss => if (sym hasFlag DEFERRED) EmptyTree else gen.mkAttributedRef(sym)))
}
}
def addBeanSetterMethod(sym: Symbol) = {
val setter = beanSetterOrGetter(sym)
if (setter != NoSymbol) {
clazz.info.decls.enter(setter)
ts += typer.typed(DefDef(
setter,
vparamss =>
if (sym hasFlag DEFERRED) EmptyTree
else Apply(gen.mkAttributedRef(sym), List(Ident(vparamss.head.head)))))
}
}
def isPublic(sym: Symbol) =
!sym.hasFlag(PRIVATE | PROTECTED) && sym.privateWithin == NoSymbol
if (!phase.erasedTypes) {
try {
if (clazz hasFlag CASE) {
val isTop = !(clazz.info.baseClasses.tail exists (_ hasFlag CASE))
// case classes are implicitly declared serializable
clazz.attributes = AnnotationInfo(SerializableAttr.tpe, List(), List()) :: clazz.attributes
if (isTop) {
for (stat <- templ.body) {
if (stat.isDef && stat.symbol.isMethod && stat.symbol.hasFlag(CASEACCESSOR) && !isPublic(stat.symbol)) {
ts += newAccessorMethod(stat)
stat.symbol.resetFlag(CASEACCESSOR)
}
}
}
if (clazz.isModuleClass) {
if (!hasOverridingImplementation(Object_toString)) ts += moduleToStringMethod
// if there's a synthetic method in a parent case class, override its equality
// with eq (see #883)
val otherEquals = clazz.info.nonPrivateMember(Object_equals.name)
if (otherEquals.owner != clazz && (otherEquals hasFlag SYNTHETICMETH)) ts += equalsModuleMethod
} else {
if (!hasOverridingImplementation(Object_hashCode)) ts += forwardingMethod(nme.hashCode_)
if (!hasOverridingImplementation(Object_toString)) ts += forwardingMethod(nme.toString_)
if (!hasOverridingImplementation(Object_equals)) ts += equalsClassMethod
}
if (!hasOverridingImplementation(Product_productPrefix)) ts += productPrefixMethod
val accessors = clazz.caseFieldAccessors
if (!hasOverridingImplementation(Product_productArity))
ts += productArityMethod(accessors.length)
if (!hasOverridingImplementation(Product_productElement))
ts += productElementMethod(accessors)
}
if (clazz.isModuleClass && hasSerializableAnnotation(clazz)) {
// If you serialize a singleton and then deserialize it twice,
// you will have two instances of your singleton, unless you implement
// the readResolve() method (see http://www.javaworld.com/javaworld/
// jw-04-2003/jw-0425-designpatterns_p.html)
// question: should we do this for all serializable singletons, or (as currently done)
// only for those that carry a @serializable annotation?
if (!hasImplementation(nme.readResolve)) ts += readResolveMethod
}
if (!forMSIL)
for (sym <- clazz.info.decls.toList)
if (!sym.getAttributes(BeanPropertyAttr).isEmpty)
if (sym.isGetter)
addBeanGetterMethod(sym)
else if (sym.isSetter)
addBeanSetterMethod(sym)
else if (sym.isMethod || sym.isType)
context.unit.error(sym.pos, "attribute `BeanProperty' is not applicable to " + sym)
} catch {
case ex: TypeError =>
if (!reporter.hasErrors) throw ex
}
}
val synthetics = ts.toList
copy.Template(
templ, templ.parents, templ.self, if (synthetics.isEmpty) templ.body else templ.body ::: synthetics)
}
}
|