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Compiler for the Scala Programming Language
/* NSC -- new Scala compiler
* Copyright 2005-2013 LAMP/EPFL
* @author Paul Phillips
*/
package scala.tools.nsc
package typechecker
import symtab.Flags._
import scala.collection.{ mutable, immutable }
import scala.reflect.internal.util.StringOps.{ ojoin }
import scala.reflect.ClassTag
import scala.reflect.runtime.{ universe => ru }
import scala.language.higherKinds
/** Logic related to method synthesis which involves cooperation between
* Namer and Typer.
*/
trait MethodSynthesis {
self: Analyzer =>
import global._
import definitions._
import CODE._
object synthesisUtil {
type TT[T] = ru.TypeTag[T]
type CT[T] = ClassTag[T]
def ValOrDefDef(sym: Symbol, body: Tree) =
if (sym.isLazy) ValDef(sym, body)
else DefDef(sym, body)
def applyTypeInternal(tags: List[TT[_]]): Type = {
val symbols = tags map compilerSymbolFromTag
val container :: args = symbols
val tparams = container.typeConstructor.typeParams
// Conservative at present - if manifests were more usable this could do a lot more.
// [Eugene to Paul] all right, they are now. what do you have in mind?
require(symbols forall (_ ne NoSymbol), "Must find all tags: " + symbols)
require(container.owner.isPackageClass, "Container must be a top-level class in a package: " + container)
require(tparams.size == args.size, "Arguments must match type constructor arity: " + tparams + ", " + args)
appliedType(container, args map (_.tpe): _*)
}
def companionType[T](implicit ct: CT[T]) =
rootMirror.getRequiredModule(ct.runtimeClass.getName).tpe
// Use these like `applyType[List, Int]` or `applyType[Map, Int, String]`
def applyType[CC](implicit t1: TT[CC]): Type =
applyTypeInternal(List(t1))
def applyType[CC[X1], X1](implicit t1: TT[CC[_]], t2: TT[X1]): Type =
applyTypeInternal(List(t1, t2))
def applyType[CC[X1, X2], X1, X2](implicit t1: TT[CC[_,_]], t2: TT[X1], t3: TT[X2]): Type =
applyTypeInternal(List(t1, t2, t3))
def applyType[CC[X1, X2, X3], X1, X2, X3](implicit t1: TT[CC[_,_,_]], t2: TT[X1], t3: TT[X2], t4: TT[X3]): Type =
applyTypeInternal(List(t1, t2, t3, t4))
def newMethodType[F](owner: Symbol)(implicit t: TT[F]): Type = {
val fnSymbol = compilerSymbolFromTag(t)
val formals = compilerTypeFromTag(t).typeArguments
assert(fnSymbol isSubClass FunctionClass(formals.size - 1), (owner, t))
val params = owner newSyntheticValueParams formals
MethodType(params, formals.last)
}
/** The annotations amongst those found on the original symbol which
* should be propagated to this kind of accessor.
*/
def deriveAnnotations(initial: List[AnnotationInfo], category: Symbol, keepClean: Boolean): List[AnnotationInfo] = {
initial filter { ann =>
// There are no meta-annotation arguments attached to `ann`
if (ann.metaAnnotations.isEmpty) {
// A meta-annotation matching `annotKind` exists on `ann`'s definition.
(ann.defaultTargets contains category) ||
// `ann`'s definition has no meta-annotations, and `keepClean` is true.
(ann.defaultTargets.isEmpty && keepClean)
}
// There are meta-annotation arguments, and one of them matches `annotKind`
else ann.metaAnnotations exists (_ matches category)
}
}
}
import synthesisUtil._
class ClassMethodSynthesis(val clazz: Symbol, localTyper: Typer) {
def mkThis = This(clazz) setPos clazz.pos.focus
def mkThisSelect(sym: Symbol) = atPos(clazz.pos.focus)(Select(mkThis, sym))
private def isOverride(name: TermName) =
clazzMember(name).alternatives exists (sym => !sym.isDeferred && (sym.owner != clazz))
def newMethodFlags(name: TermName) = {
val overrideFlag = if (isOverride(name)) OVERRIDE else 0L
overrideFlag | SYNTHETIC
}
def newMethodFlags(method: Symbol) = {
val overrideFlag = if (isOverride(method.name)) OVERRIDE else 0L
(method.flags | overrideFlag | SYNTHETIC) & ~DEFERRED
}
private def finishMethod(method: Symbol, f: Symbol => Tree): Tree =
localTyper typed ValOrDefDef(method, f(method))
private def createInternal(name: Name, f: Symbol => Tree, info: Type): Tree = {
val m = clazz.newMethod(name.toTermName, clazz.pos.focus, newMethodFlags(name))
finishMethod(m setInfoAndEnter info, f)
}
private def createInternal(name: Name, f: Symbol => Tree, infoFn: Symbol => Type): Tree = {
val m = clazz.newMethod(name.toTermName, clazz.pos.focus, newMethodFlags(name))
finishMethod(m setInfoAndEnter infoFn(m), f)
}
private def cloneInternal(original: Symbol, f: Symbol => Tree, name: Name): Tree = {
val m = original.cloneSymbol(clazz, newMethodFlags(original), name) setPos clazz.pos.focus
finishMethod(clazz.info.decls enter m, f)
}
private def cloneInternal(original: Symbol, f: Symbol => Tree): Tree =
cloneInternal(original, f, original.name)
def clazzMember(name: Name) = clazz.info nonPrivateMember name
def typeInClazz(sym: Symbol) = clazz.thisType memberType sym
/** Function argument takes the newly created method symbol of
* the same type as `name` in clazz, and returns the tree to be
* added to the template.
*/
def overrideMethod(name: Name)(f: Symbol => Tree): Tree =
overrideMethod(clazzMember(name))(f)
def overrideMethod(original: Symbol)(f: Symbol => Tree): Tree =
cloneInternal(original, sym => f(sym setFlag OVERRIDE))
def deriveMethod(original: Symbol, nameFn: Name => Name)(f: Symbol => Tree): Tree =
cloneInternal(original, f, nameFn(original.name))
def createMethod(name: Name, paramTypes: List[Type], returnType: Type)(f: Symbol => Tree): Tree =
createInternal(name, f, (m: Symbol) => MethodType(m newSyntheticValueParams paramTypes, returnType))
def createMethod(name: Name, returnType: Type)(f: Symbol => Tree): Tree =
createInternal(name, f, NullaryMethodType(returnType))
def createMethod(original: Symbol)(f: Symbol => Tree): Tree =
createInternal(original.name, f, original.info)
def forwardMethod(original: Symbol, newMethod: Symbol)(transformArgs: List[Tree] => List[Tree]): Tree =
createMethod(original)(m => gen.mkMethodCall(newMethod, transformArgs(m.paramss.head map Ident)))
def createSwitchMethod(name: Name, range: Seq[Int], returnType: Type)(f: Int => Tree) = {
createMethod(name, List(IntClass.tpe), returnType) { m =>
val arg0 = Ident(m.firstParam)
val default = DEFAULT ==> THROW(IndexOutOfBoundsExceptionClass, arg0)
val cases = range.map(num => CASE(LIT(num)) ==> f(num)).toList :+ default
Match(arg0, cases)
}
}
// def foo() = constant
def constantMethod(name: Name, value: Any): Tree = {
val constant = Constant(value)
createMethod(name, Nil, constant.tpe)(_ => Literal(constant))
}
// def foo = constant
def constantNullary(name: Name, value: Any): Tree = {
val constant = Constant(value)
createMethod(name, constant.tpe)(_ => Literal(constant))
}
}
/** There are two key methods in here.
*
* 1) Enter methods such as enterGetterSetterare called
* from Namer with a tree which may generate further trees such as accessors or
* implicit wrappers. Some setup is performed. In general this creates symbols
* and enters them into the scope of the owner.
*
* 2) addDerivedTrees is called from Typer when a Template is typed.
* It completes the job, returning a list of trees with their symbols
* set to those created in the enter methods. Those trees then become
* part of the typed template.
*/
trait MethodSynth {
self: Namer =>
import NamerErrorGen._
def enterImplicitWrapper(tree: ClassDef) {
ImplicitClassWrapper(tree).createAndEnterSymbol()
}
def enterGetterSetter(tree: ValDef) {
val ValDef(mods, name, _, _) = tree
if (nme.isSetterName(name))
ValOrValWithSetterSuffixError(tree)
val getter = Getter(tree).createAndEnterSymbol()
tree.symbol = (
if (mods.isLazy) enterLazyVal(tree, getter)
else {
if (mods.isPrivateLocal)
PrivateThisCaseClassParameterError(tree)
// Create the setter if necessary.
if (mods.isMutable)
Setter(tree).createAndEnterSymbol()
// If abstract, the tree gets the getter's symbol. Otherwise, create a field.
if (mods.isDeferred) getter setPos tree.pos
else enterStrictVal(tree)
}
)
enterBeans(tree)
}
def addDerivedTrees(typer: Typer, stat: Tree): List[Tree] = stat match {
case vd @ ValDef(mods, name, tpt, rhs) if !noFinishGetterSetter(vd) && !vd.symbol.isLazy =>
// If we don't save the annotations, they seem to wander off.
val annotations = stat.symbol.initialize.annotations
( allValDefDerived(vd)
map (acc => atPos(vd.pos.focus)(acc derive annotations))
filterNot (_ eq EmptyTree)
)
case cd @ ClassDef(mods, _, _, _) if mods.isImplicit =>
val annotations = stat.symbol.initialize.annotations
// TODO: need to shuffle annotations between wrapper and class.
val wrapper = ImplicitClassWrapper(cd)
val meth = wrapper.derivedSym
context.unit.synthetics get meth match {
case Some(mdef) =>
context.unit.synthetics -= meth
meth setAnnotations deriveAnnotations(annotations, MethodTargetClass, false)
cd.symbol setAnnotations deriveAnnotations(annotations, ClassTargetClass, true)
List(cd, mdef)
case _ =>
// Shouldn't happen, but let's give ourselves a reasonable error when it does
abort("No synthetics for " + meth + ": synthetics contains " + context.unit.synthetics.keys.mkString(", "))
}
case _ =>
stat :: Nil
}
def standardAccessors(vd: ValDef): List[DerivedFromValDef] = (
if (vd.mods.isMutable && !vd.mods.isLazy) List(Getter(vd), Setter(vd))
else List(Getter(vd))
)
def beanAccessors(vd: ValDef): List[DerivedFromValDef] = {
val setter = if (vd.mods.isMutable) List(BeanSetter(vd)) else Nil
if (forMSIL) Nil
else if (vd.symbol hasAnnotation BeanPropertyAttr)
BeanGetter(vd) :: setter
else if (vd.symbol hasAnnotation BooleanBeanPropertyAttr)
BooleanBeanGetter(vd) :: setter
else Nil
}
def allValDefDerived(vd: ValDef) = {
val field = if (vd.mods.isDeferred) Nil else List(Field(vd))
field ::: standardAccessors(vd) ::: beanAccessors(vd)
}
/** This trait assembles what's needed for synthesizing derived methods.
* Important: Typically, instances of this trait are created TWICE for each derived
* symbol; once form Namers in an enter method, and once from Typers in addDerivedTrees.
* So it's important that creating an instance of Derived does not have a side effect,
* or if it has a side effect, control that it is done only once.
*/
trait Derived {
/** The tree from which we are deriving a synthetic member. Typically, that's
* given as an argument of the instance. */
def tree: Tree
/** The name of the method */
def name: TermName
/** The flags that are retained from the original symbol */
def flagsMask: Long
/** The flags that the derived symbol has in addition to those retained from
* the original symbol*/
def flagsExtra: Long
/** type completer for the synthetic member.
*/
def completer(sym: Symbol): Type
/** The derived symbol. It is assumed that this symbol already exists and has been
* entered in the parent scope when derivedSym is called */
def derivedSym: Symbol
/** The definition tree of the derived symbol. */
def derivedTree: Tree
}
trait DerivedFromMemberDef extends Derived {
def tree: MemberDef
def enclClass: Symbol
// Final methods to make the rest easier to reason about.
final def mods = tree.mods
final def basisSym = tree.symbol
final def derivedFlags: Long = basisSym.flags & flagsMask | flagsExtra
}
trait DerivedFromClassDef extends DerivedFromMemberDef {
def tree: ClassDef
final def enclClass = basisSym.owner.enclClass
}
trait DerivedFromValDef extends DerivedFromMemberDef {
def tree: ValDef
final def enclClass = basisSym.enclClass
/** Which meta-annotation is associated with this kind of entity.
* Presently one of: field, getter, setter, beanGetter, beanSetter, param.
*/
def category: Symbol
final def completer(sym: Symbol) = namerOf(sym).accessorTypeCompleter(tree, isSetter)
final def fieldSelection = Select(This(enclClass), basisSym)
final def derivedMods: Modifiers = mods & flagsMask | flagsExtra mapAnnotations (_ => Nil)
def derivedSym: Symbol = tree.symbol
def derivedTree: Tree = EmptyTree
def isSetter = false
def isDeferred = mods.isDeferred
def keepClean = false // whether annotations whose definitions are not meta-annotated should be kept.
def validate() { }
def createAndEnterSymbol(): Symbol = {
val sym = owner.newMethod(name, tree.pos.focus, (tree.mods.flags & flagsMask) | flagsExtra)
setPrivateWithin(tree, sym)
enterInScope(sym)
sym setInfo completer(sym)
}
private def logDerived(result: Tree): Tree = {
debuglog("[+derived] " + ojoin(mods.flagString, basisSym.accurateKindString, basisSym.getterName.decode)
+ " (" + derivedSym + ")\n " + result)
result
}
final def derive(initial: List[AnnotationInfo]): Tree = {
validate()
derivedSym setAnnotations deriveAnnotations(initial, category, keepClean)
logDerived(derivedTree)
}
}
trait DerivedGetter extends DerivedFromValDef {
// TODO
}
trait DerivedSetter extends DerivedFromValDef {
override def isSetter = true
private def setterParam = derivedSym.paramss match {
case (p :: Nil) :: _ => p
case _ => NoSymbol
}
private def setterRhs = (
if (mods.isDeferred || derivedSym.isOverloaded) EmptyTree
else Assign(fieldSelection, Ident(setterParam))
)
private def setterDef = DefDef(derivedSym, setterRhs)
override def derivedTree: Tree = if (setterParam == NoSymbol) EmptyTree else setterDef
}
/** A synthetic method which performs the implicit conversion implied by
* the declaration of an implicit class.
*/
case class ImplicitClassWrapper(tree: ClassDef) extends DerivedFromClassDef {
def completer(sym: Symbol): Type = ??? // not needed
def createAndEnterSymbol(): Symbol = enterSyntheticSym(derivedTree)
def derivedSym: Symbol = {
// Only methods will do! Don't want to pick up any stray
// companion objects of the same name.
val result = enclClass.info decl name suchThat (x => x.isMethod && x.isSynthetic)
assert(result != NoSymbol, "not found: "+name+" in "+enclClass+" "+enclClass.info.decls)
result
}
def derivedTree: DefDef =
factoryMeth(mods & flagsMask | flagsExtra, name, tree, symbolic = false)
def flagsExtra: Long = METHOD | IMPLICIT | SYNTHETIC
def flagsMask: Long = AccessFlags
def name: TermName = tree.name.toTermName
}
case class Getter(tree: ValDef) extends DerivedGetter {
def name = tree.name
def category = GetterTargetClass
def flagsMask = GetterFlags
def flagsExtra = ACCESSOR | ( if (tree.mods.isMutable) 0 else STABLE )
override def derivedSym = (
if (mods.isDeferred) basisSym
else basisSym.getter(enclClass)
)
override def validate() {
assert(derivedSym != NoSymbol, tree)
if (derivedSym.isOverloaded)
GetterDefinedTwiceError(derivedSym)
super.validate()
}
override def derivedTree: DefDef = {
// For existentials, don't specify a type for the getter, even one derived
// from the symbol! This leads to incompatible existentials for the field and
// the getter. Let the typer do all the work. You might think "why only for
// existentials, why not always," and you would be right, except: a single test
// fails, but it looked like some work to deal with it. Test neg/t0606.scala
// starts compiling (instead of failing like it's supposed to) because the typer
// expects to be able to identify escaping locals in typedDefDef, and fails to
// spot that brand of them. In other words it's an artifact of the implementation.
val tpt = derivedSym.tpe.finalResultType match {
case ExistentialType(_, _) => TypeTree()
case tp => TypeTree(tp)
}
tpt setPos derivedSym.pos.focus
// keep type tree of original abstract field
if (mods.isDeferred)
tpt setOriginal tree.tpt
// TODO - reconcile this with the DefDef creator in Trees (which
// at this writing presented no way to pass a tree in for tpt.)
atPos(derivedSym.pos) {
DefDef(
Modifiers(derivedSym.flags),
derivedSym.name.toTermName,
Nil,
Nil,
tpt,
if (mods.isDeferred) EmptyTree else gen.mkCheckInit(fieldSelection)
) setSymbol derivedSym
}
}
}
case class Setter(tree: ValDef) extends DerivedSetter {
def name = nme.getterToSetter(tree.name)
def category = SetterTargetClass
def flagsMask = SetterFlags
def flagsExtra = ACCESSOR
override def derivedSym = basisSym.setter(enclClass)
}
case class Field(tree: ValDef) extends DerivedFromValDef {
def name = nme.getterToLocal(tree.name)
def category = FieldTargetClass
def flagsMask = FieldFlags
def flagsExtra = PrivateLocal
// By default annotations go to the field, except if the field is
// generated for a class parameter (PARAMACCESSOR).
override def keepClean = !mods.isParamAccessor
override def derivedTree = (
if (mods.isDeferred) EmptyTree
else copyValDef(tree)(mods = mods | flagsExtra, name = this.name)
)
}
case class Param(tree: ValDef) extends DerivedFromValDef {
def name = tree.name
def category = ParamTargetClass
def flagsMask = -1L
def flagsExtra = 0L
override def keepClean = true
override def derivedTree = EmptyTree
}
def validateParam(tree: ValDef) {
Param(tree).derive(tree.symbol.annotations)
}
sealed abstract class BeanAccessor(bean: String) extends DerivedFromValDef {
val name = newTermName(bean + tree.name.toString.capitalize)
def flagsMask = BeanPropertyFlags
def flagsExtra = 0
override def derivedSym = enclClass.info decl name
}
trait AnyBeanGetter extends BeanAccessor with DerivedGetter {
def category = BeanGetterTargetClass
override def validate() {
if (derivedSym == NoSymbol) {
// the namer decides whether to generate these symbols or not. at that point, we don't
// have symbolic information yet, so we only look for annotations named "BeanProperty".
BeanPropertyAnnotationLimitationError(tree)
}
super.validate()
}
}
trait NoSymbolBeanGetter extends AnyBeanGetter {
// Derives a tree without attempting to use the original tree's symbol.
override def derivedTree = {
atPos(tree.pos.focus) {
DefDef(derivedMods, name, Nil, ListOfNil, tree.tpt.duplicate,
if (isDeferred) EmptyTree else Select(This(owner), tree.name)
)
}
}
override def createAndEnterSymbol(): Symbol = enterSyntheticSym(derivedTree)
}
case class BooleanBeanGetter(tree: ValDef) extends BeanAccessor("is") with AnyBeanGetter { }
case class BeanGetter(tree: ValDef) extends BeanAccessor("get") with AnyBeanGetter { }
case class BeanSetter(tree: ValDef) extends BeanAccessor("set") with DerivedSetter {
def category = BeanSetterTargetClass
}
// No Symbols available.
private def beanAccessorsFromNames(tree: ValDef) = {
val ValDef(mods, name, tpt, _) = tree
val hasBP = mods hasAnnotationNamed tpnme.BeanPropertyAnnot
val hasBoolBP = mods hasAnnotationNamed tpnme.BooleanBeanPropertyAnnot
if (hasBP || hasBoolBP) {
val getter = (
if (hasBP) new BeanGetter(tree) with NoSymbolBeanGetter
else new BooleanBeanGetter(tree) with NoSymbolBeanGetter
)
getter :: {
if (mods.isMutable) List(BeanSetter(tree)) else Nil
}
}
else Nil
}
protected def enterBeans(tree: ValDef) {
if (forMSIL)
return
val ValDef(mods, name, _, _) = tree
val beans = beanAccessorsFromNames(tree)
if (beans.nonEmpty) {
if (!name.charAt(0).isLetter)
BeanPropertyAnnotationFieldWithoutLetterError(tree)
else if (mods.isPrivate) // avoids name clashes with private fields in traits
BeanPropertyAnnotationPrivateFieldError(tree)
// Create and enter the symbols here, add the trees in finishGetterSetter.
beans foreach (_.createAndEnterSymbol())
}
}
}
}