path: root/src/dotty/tools/dotc/core/pickling/TreePickler.scala

package dotty.tools
package dotc
package core
package pickling

import util.Util.{bestFit, dble}
import ast.Trees._
import PickleFormat._
import core._
import Contexts._, Symbols._, Types._, Names._, Constants._, Decorators._
import collection.mutable
import TastyBuffer._

class TreePickler(pickler: TastyPickler, picklePositions: Boolean) {
  val buf = new TreeBuffer
  pickler.newSection("ASTs", buf)
  import buf._
  import pickler.nameBuffer.nameIndex
  import ast.tpd._

  private val symRefs = new mutable.HashMap[Symbol, Addr]
  private val forwardSymRefs = new mutable.HashMap[Symbol, List[Addr]]
  private val pickledTypes = new java.util.IdentityHashMap[Type, Any] // Value type is really Addr, but that's not compatible with null

  private def withLength(op: => Unit) = {
    val lengthAddr = reserveRef(relative = true)
    op
    fillRef(lengthAddr, currentAddr, relative = true)
  }

  def registerDef(sym: Symbol) = {
    symRefs(sym) = currentAddr
    forwardSymRefs.get(sym) match {
      case Some(refs) =>
        refs.foreach(fillRef(_, currentAddr, relative = false))
        forwardSymRefs -= sym
      case None =>
    }
  }

  private def pickleName(name: Name) = writeNat(nameIndex(name).index)
  private def pickleName(name: TastyName) = writeNat(nameIndex(name).index)
  private def pickleNameAndSig(name: Name, sig: Signature) = {
    val Signature(params, result) = sig
    pickleName(TastyName.Signed(nameIndex(name), params.map(nameIndex), nameIndex(result)))
  }

  private def pickleSym(sym: Symbol) = symRefs.get(sym) match {
    case Some(label) =>
      writeRef(label)
    case None =>
      val ref = reserveRef(relative = false)
      forwardSymRefs(sym) = ref :: forwardSymRefs.getOrElse(sym, Nil)
  }

  def pickle(tree: Tree)(implicit ctx: Context) = {
    
    def pickleConstant(c: Constant): Unit = {
      def pickleNum(nonNegTag: Int, negTag: Int) = {
        val x = c.longValue
        if (x < 0) {
          writeByte(negTag)
          writeLongNat(-(x + 1))
        }
        else {
          writeByte(nonNegTag)
          writeLongNat(x)
        }
      }
      c.tag match {
        case UnitTag => 
          writeByte(UNITconst)
        case BooleanTag => 
          writeByte(if (c.booleanValue) TRUEconst else FALSEconst)
        case ByteTag => 
          pickleNum(BYTEconst, BYTEneg)
        case ShortTag => 
          pickleNum(SHORTconst, SHORTneg)
        case CharTag => 
          writeByte(CHARconst)
          writeNat(c.charValue)
        case IntTag => 
          pickleNum(INTconst, INTneg)
        case LongTag => 
          pickleNum(LONGconst, LONGneg)
        case FloatTag => 
          writeByte(FLOATconst)
          writeRaw(java.lang.Float.floatToRawIntBits(c.floatValue), 4)
        case DoubleTag =>
          writeByte(DOUBLEconst)
          writeRaw(java.lang.Double.doubleToRawLongBits(c.doubleValue), 8)
        case StringTag =>
          writeByte(STRINGconst)
          writeNat(nameIndex(c.stringValue).index)
        case NullTag => 
          writeByte(NULLconst)
        case ClazzTag =>
          writeByte(CLASSconst)
          withLength { pickleType(c.typeValue) }
        case EnumTag =>
          writeByte(ENUMconst)
          withLength { pickleType(c.symbolValue.termRef) }          
      }
    }

    def pickleType(tpe: Type): Unit = {
      val prev = pickledTypes.get(tpe)
      if (prev == null) {
        val addr = currentAddr
        pickleNewType(tpe)
        pickledTypes.put(tpe, addr)
      }
      else {
        writeByte(SHARED)
        writeRef(prev.asInstanceOf[Addr])
      }
    }
      
    def pickleNewType(tpe: Type)= tpe match {
      case ConstantType(value) => pickleConstant(value)
      case tpe: WithFixedSym =>
        if (tpe.prefix == NoPrefix) {
          writeByte(if (tpe.isType) TYPEREFdirect else TERMREFdirect)
          pickleSym(tpe.symbol)
        }
        else {
          writeByte(if (tpe.isType) TYPEREFsymbol else TERMREFsymbol)
          pickleType(tpe.prefix); pickleSym(tpe.symbol)          
        }
      case tpe: TermRefWithSignature =>
        writeByte(TERMREF)
        pickleType(tpe.prefix); pickleNameAndSig(tpe.name, tpe.signature)
      case tpe: NamedType =>
        writeByte(if (tpe.isType) TYPEREF else TERMREF)
        pickleType(tpe.prefix); pickleName(tpe.name)
      case tpe: ThisType =>
        writeByte(THIS)
        pickleType(tpe.tref)
      case tpe: SuperType =>
        writeByte(SUPERtype)
        withLength { pickleType(tpe.thistpe); pickleType(tpe.supertpe)}
      case tpe: SkolemType =>
        writeByte(SKOLEMtype)
        withLength { pickleType(tpe.underlying) }
      case tpe: RefinedType =>
        val args = tpe.argInfos(interpolate = false)
        if (args.isEmpty) {
          writeByte(REFINEDtype)
          withLength { pickleName(tpe.refinedName); pickleType(tpe.refinedInfo) }
        }
        else {
          writeByte(APPLIEDtype)
          withLength { pickleType(tpe.withoutArgs(args)); args.foreach(pickleType) }
        }
      case tpe: TypeAlias =>
        writeByte(TYPEALIAS)
        withLength { pickleType(tpe.alias) }
      case tpe: TypeBounds =>
        writeByte(TYPEBOUNDS)
        withLength { pickleType(tpe.lo); pickleType(tpe.hi) }
      case tpe: AnnotatedType =>
        writeByte(ANNOTATED)
        withLength { pickleTree(tpe.annot.tree); pickleType(tpe.tpe) }
      case tpe: AndOrType =>
        writeByte(if (tpe.isAnd) ANDtype else ORtype)
        withLength { pickleType(tpe.tp1); pickleType(tpe.tp2) }
      case tpe: ExprType =>
        writeByte(BYNAMEtype)
        withLength { pickleType(tpe.underlying) }
      case NoType =>
        writeByte(NOTYPE)
//      case NoPrefix =>    // not sure we need this!
//        writeByte(NOPREFIX)
    }
    
    def pickleTpt(tpt: Tree): Unit = pickleType(tpt.tpe) // TODO correlate with original when generating positions
    
    def pickleTreeIfNonEmpty(tree: Tree): Unit = 
      if (!tree.isEmpty) pickleTree(tree)

    def pickleTree(tree: Tree): Unit = tree match {
      case Ident(_) | This(_) => 
        pickleType(tree.tpe)
      case Select(qual, name) => 
        writeByte(SELECT)
        val sig = tree.tpe.signature
        if (sig == Signature.NotAMethod) pickleName(name)
        else pickleNameAndSig(name, sig)
      case Apply(fun, args) =>
        writeByte(APPLY)
        withLength {
          pickleTree(fun)
          args.foreach(pickleTree)
        }
      case TypeApply(fun, args) =>
        writeByte(TYPEAPPLY)
        withLength {
          pickleTree(fun)
          args.foreach(pickleTree)
        }
      case Literal(const) =>
        pickleConstant(const)
      case Super(qual, mix) =>
        writeByte(SUPER)
        withLength { 
          pickleTree(qual);
          if (!mix.isEmpty) {
            val SuperType(_, mixinType) = tree.tpe
            pickleType(mixinType)
          }
        }
      case New(tpt) =>
        writeByte(NEW)
        withLength { pickleTpt(tpt) }
      case Pair(left, right) =>
        writeByte(PAIR)
        withLength { pickleTree(left); pickleTree(right) }
      case Typed(expr, tpt) =>
        writeByte(TYPED)
        withLength { pickleTree(expr); pickleTpt(tpt) }
      case NamedArg(name, arg) =>
        writeByte(NAMEDARG)
        withLength { pickleName(name); pickleTree(arg) }
      case Assign(lhs, rhs) =>
        writeByte(ASSIGN)
        withLength { pickleTree(lhs); pickleTree(rhs) }
      case Block(stats, expr) =>
        writeByte(BLOCK)
        withLength { pickleTree(expr); stats.foreach(pickleTree) }
      case If(cond, thenp, elsep) =>
        writeByte(IF)
        withLength{ pickleTree(cond); pickleTree(thenp); pickleTree(elsep) }
      case Closure(env, meth, tpt) => 
        writeByte(CLOSURE)
        withLength{ pickleTree(meth); pickleTpt(tpt); env.foreach(pickleTree) }
      case Match(selector, cases) =>
        writeByte(MATCH)
        withLength { pickleTree(selector); cases.foreach(pickleTree) }
      case CaseDef(pat, guard, rhs) =>
        writeByte(CASEDEF)
        withLength { pickleTree(pat); pickleTree(guard); pickleTree(rhs) }
      case Return(expr, from) =>
        writeByte(RETURN)
        withLength { pickleSym(from.symbol); pickleTreeIfNonEmpty(expr) }
      case Try(block, cases, finalizer) =>
        writeByte(TRY)
        withLength { pickleTree(block); cases.foreach(pickleTree); pickleTreeIfNonEmpty(finalizer) }
      case Throw(expr) =>
        writeByte(THROW)
        withLength { pickleTree(expr) }
      case SeqLiteral(elems) =>
        writeByte(if (tree.isInstanceOf[JavaSeqLiteral]) JSEQLITERAL else SEQLITERAL)
        withLength { elems.foreach(pickleTree) }
      case TypeTree(original) =>
        pickleTpt(tree)
      case Bind(name, body) =>
        registerDef(tree.symbol)
        writeByte(BIND)
        withLength { pickleName(name); pickleType(tree.symbol.info); pickleTree(body) }
      case Alternative(alts) =>
        writeByte(ALTERNATIVE)
        withLength { alts.foreach(pickleTree) }
      case UnApply(fun, implicits, patterns) =>
        writeByte(UNAPPLY)
        withLength { 
          pickleTree(fun)
          for (implicitArg <- implicits) {
            writeByte(IMPLICITARG)
            withLength { pickleTree(implicitArg) }
          }
          patterns.foreach(pickleTree) 
        }
      case tree: ValDef =>
        pickleDef(VALDEF, tree.symbol, tree.rhs)
      case tree: DefDef =>
        def pickleParams = {
          for (tparam <- tree.tparams) pickleDef(TYPEPARAM, tparam.symbol, EmptyTree)
          for (vparams <- tree.vparamss) {
            writeByte(PARAMS)
            withLength {
              for (vparam <- vparams) pickleDef(PARAM, vparam.symbol, EmptyTree)
            }
          }          
        }
        pickleDef(DEFDEF, tree.symbol, tree.rhs, pickleParams)
      case tree: TypeDef =>
        pickleDef(TYPEDEF, tree.symbol, tree.rhs)
      case tree: Template =>
        writeByte(TEMPLATE)
        withLength {
          tree.parents.foreach(pickleTree)
          if (!tree.self.isEmpty)
            pickleDef(PARAM, tree.self.symbol, EmptyTree)
          pickleTreeIfNonEmpty(tree.constr)
          tree.body.foreach(pickleTree)
        }
      case Import(expr, selectors) =>
        writeByte(IMPORT)
        withLength {
          pickleTree(expr)
          selectors foreach {
            case Pair(Ident(from), Ident(to)) => 
              writeByte(RENAMED)
              withLength { pickleName(from); pickleName(to) }
            case Ident(name) =>
              writeByte(IMPORTED)
              withLength { pickleName(name) }
          }
        }
      case PackageDef(pid, stats) =>
        writeByte(PACKAGE)
        withLength { pickleType(pid.tpe); stats.foreach(pickleTree) }
      case Annotated(annot, arg) =>
        writeByte(ANNOTATED)
        withLength { pickleTree(annot); pickleTree(arg) }
    }
    
    def pickleDef(tag: Int, sym: Symbol, rhs: Tree, pickleParams: => Unit = ()) = {
      registerDef(sym)
      writeByte(tag)
      withLength {
        pickleName(sym.name)
        pickleParams
        if (tag != TYPEDEF) pickleType(sym.info.finalResultType)
        if (tag != PARAM && tag != TYPEPARAM) pickleTree(rhs)
        pickleModifiers(sym)
      }
    }

    def pickleModifiers(sym: Symbol): Unit = {
      import Flags._
      val flags = sym.flags
      val privateWithin = sym.privateWithin
      if (privateWithin.exists) {
        writeByte(if (flags is Protected) PROTECTEDqualified else PRIVATEqualified)
        pickleSym(privateWithin)
      }
      if (flags is Private) writeByte(PRIVATE)
      if (flags is Protected) if (!privateWithin.exists) writeByte(PROTECTED)
      if (flags is Final) writeByte(FINAL)
      if (flags is Case) writeByte(CASE)
      if (flags is Override) writeByte(OVERRIDE)
      if (flags is Inline) writeByte(INLINE)
      if (flags is JavaStatic) writeByte(STATIC)
      if (flags is Module) writeByte(MODULE)
      if (flags is Local) writeByte(LOCAL)
      if (flags is Synthetic) writeByte(SYNTHETIC)
      if (flags is Artifact) writeByte(ARTIFACT)
      if (flags is Scala2x) writeByte(SCALA2X) 
      if (sym.isTerm) {
        if (flags is Implicit) writeByte(IMPLICIT)
        if (flags is Lazy) writeByte(LAZY)
        if (flags is AbsOverride) writeByte(ABSOVERRIDE)
        if (flags is Mutable) writeByte(MUTABLE)
        if (flags is Accessor) writeByte(FIELDaccessor)
        if (flags is ParamAccessor) writeByte(PARAMaccessor)
        if (flags is CaseAccessor) writeByte(CASEaccessor)  
        if (flags is DefaultParameterized) writeByte(DEFAULTparameterized)
        if (flags is DefaultInit) writeByte(DEFAULTinit)
      } else {
        if (flags is Sealed) writeByte(SEALED)
        if (flags is Abstract) writeByte(ABSTRACT)      
        if (flags is Covariant) writeByte(COVARIANT)
        if (flags is Contravariant) writeByte(CONTRAVARIANT)
      }
      sym.annotations.foreach(ann => pickleTree(ann.tree))
    }

    pickleTree(tree)
  }  
}