classfileparser.scala

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/* NSC -- new Scala compiler
 * Copyright 2005-2008 LAMP/EPFL
 * @author  Martin Odersky
 */
// $Id: ClassfileParser.scala 14134 2008-02-26 09:50:05Z odersky $

package scala.tools.nsc.symtab.classfile

import java.io.IOException
import java.lang.Integer.toHexString

import scala.collection.immutable.{Map, ListMap}
import scala.collection.mutable.{ListBuffer, ArrayBuffer}
import scala.tools.nsc.io.AbstractFile
import scala.tools.nsc.util.{Position, NoPosition}


/** This abstract class implements a class file parser.
 *
 *  @author Martin Odersky
 *  @version 1.0
 */
abstract class ClassfileParser {
  def sourcePath : AbstractFile = null

  val global: Global
  import global._

  import ClassfileConstants._
  import Flags._

  protected var in: AbstractFileReader = _  // the class file reader
  protected var clazz: Symbol = _           // the class symbol containing dynamic members
  protected var staticModule: Symbol = _    // the module symbol containing static members
  protected var instanceDefs: Scope = _     // the scope of all instance definitions
  protected var staticDefs: Scope = _       // the scope of all static definitions
  protected var pool: ConstantPool = _      // the classfile's constant pool
  protected var isScala: Boolean = _        // does class file describe a scala class?
  protected var hasMeta: Boolean = _        // does class file contain jaco meta attribute?s
  protected var busy: Boolean = false       // lock to detect recursive reads
  protected var classTParams = Map[Name,Symbol]()

  private object metaParser extends MetaParser {
    val global: ClassfileParser.this.global.type = ClassfileParser.this.global
  }

  private object unpickler extends UnPickler {
    val global: ClassfileParser.this.global.type = ClassfileParser.this.global
  }

  def parse(file: AbstractFile, root: Symbol) = try {
    def handleError(e: Exception) = {
      if (settings.debug.value) e.printStackTrace() //debug
      throw new IOException("class file '" + in.file + "' is broken\n(" + {
        if (e.getMessage() != null) e.getMessage()
        else e.getClass.toString
      } + ")")
    }
    assert(!busy)
    busy = true
    /*root match {
      case cs: ClassSymbol =>
        cs.classFile = file
      case ms: ModuleSymbol =>
        ms.moduleClass.asInstanceOf[ClassSymbol].classFile = file
      case _ =>
        println("Skipping class: " + root + ": " + root.getClass)
    }
*/
    this.in = new AbstractFileReader(file)
    if (root.isModule) {
      this.clazz = root.linkedClassOfModule
      this.staticModule = root
    } else {
      this.clazz = root
      this.staticModule = root.linkedModuleOfClass
    }
    this.isScala = false
    this.hasMeta = false
    try {
      parseHeader
      this.pool = new ConstantPool
      parseClass()
    } catch {
      case e: FatalError => handleError(e)
      case e: RuntimeException => handleError(e)
    }
  } finally {
    busy = false
  }

  protected def statics: Symbol = staticModule.moduleClass

  private def parseHeader {
    val magic = in.nextInt
    if (magic != JAVA_MAGIC)
      throw new IOException("class file '" + in.file + "' "
                            + "has wrong magic number 0x" + toHexString(magic)
                            + ", should be 0x" + toHexString(JAVA_MAGIC))
    val minorVersion = in.nextChar
    val majorVersion = in.nextChar
    if ((majorVersion < JAVA_MAJOR_VERSION) ||
        ((majorVersion == JAVA_MAJOR_VERSION) &&
         (minorVersion < JAVA_MINOR_VERSION)))
      throw new IOException("class file '" + in.file + "' "
                            + "has unknown version "
                            + majorVersion + "." + minorVersion
                            + ", should be at least "
                            + JAVA_MAJOR_VERSION + "." + JAVA_MINOR_VERSION)
  }

  class ConstantPool {
    private val len = in.nextChar
    private val starts = new Array[Int](len)
    private val values = new Array[AnyRef](len)
    private val internalized = new Array[Name](len)

    { var i = 1
      while (i < starts.length) {
        starts(i) = in.bp
        i += 1
        in.nextByte match {
          case CONSTANT_UTF8 | CONSTANT_UNICODE =>
            in.skip(in.nextChar)
          case CONSTANT_CLASS | CONSTANT_STRING =>
            in.skip(2)
          case CONSTANT_FIELDREF | CONSTANT_METHODREF | CONSTANT_INTFMETHODREF
             | CONSTANT_NAMEANDTYPE | CONSTANT_INTEGER | CONSTANT_FLOAT =>
            in.skip(4)
          case CONSTANT_LONG | CONSTANT_DOUBLE =>
            in.skip(8)
            i += 1
          case _ =>
            errorBadTag(in.bp - 1)
        }
      }
    }

    def getName(index: Int): Name = {
      if (index <= 0 || len <= index) errorBadIndex(index)
      var name = values(index).asInstanceOf[Name]
      if (name eq null) {
        val start = starts(index)
        if (in.buf(start) != CONSTANT_UTF8) errorBadTag(start)
        name = newTermName(in.buf, start + 3, in.getChar(start + 1))
        values(index) = name
      }
      name
    }

    def getExternalName(index: Int): Name = {
      if (index <= 0 || len <= index) errorBadIndex(index)
      if (internalized(index) eq null) {
        internalized(index) = getName(index).replace('/', '.')
      }
      internalized(index)
    }

    def getClassSymbol(index: Int): Symbol = {
      if (index <= 0 || len <= index) errorBadIndex(index)
      var c = values(index).asInstanceOf[Symbol]
      if (c eq null) {
        val start = starts(index)
        if (in.buf(start) != CONSTANT_CLASS) errorBadTag(start)
        val name = getExternalName(in.getChar(start + 1))
        if (name.endsWith("$"))
          c = definitions.getModule(name.subName(0, name.length - 1))
        else
          c = classNameToSymbol(name)
        values(index) = c
      }
      c
    }
    
    /** Return the symbol of the class member at <code>index</code>.
     *  The following special cases exist:
     *   - If the member refers to special MODULE$ static field, return
     *  the symbol of the corresponding module.
     *   - If the member is a field, and is not found with the given name,
     *     another try is made by appending nme.LOCAL_SUFFIX
     *   - If no symbol is found in the right tpe, a new try is made in the 
     *     companion class, in case the owner is an implementation class.
     */
    def getMemberSymbol(index: Int, static: Boolean): Symbol = {
      if (index <= 0 || len <= index) errorBadIndex(index)
      var f = values(index).asInstanceOf[Symbol]
      if (f eq null) {
        val start = starts(index)
        if (in.buf(start) != CONSTANT_FIELDREF &&
            in.buf(start) != CONSTANT_METHODREF &&
            in.buf(start) != CONSTANT_INTFMETHODREF) errorBadTag(start)
        val ownerTpe = getClassOrArrayType(in.getChar(start + 1))
        val (name, tpe) = getNameAndType(in.getChar(start + 3), ownerTpe)
        if (name == nme.MODULE_INSTANCE_FIELD) {
          val index = in.getChar(start + 1)
          val name = getExternalName(in.getChar(starts(index) + 1))
          //assert(name.endsWith("$"), "Not a module class: " + name)
          f = definitions.getModule(name.subName(0, name.length - 1))
        } else {
          val owner = if (static) ownerTpe.typeSymbol.linkedClassOfClass else ownerTpe.typeSymbol
//          println("\t" + owner.info.member(name).tpe.widen + " =:= " + tpe)
          f = owner.info.member(name).suchThat(_.tpe.widen =:= tpe)
          if (f == NoSymbol)
            f = owner.info.member(newTermName(name.toString + nme.LOCAL_SUFFIX)).suchThat(_.tpe =:= tpe)
          if (f == NoSymbol) {
            // if it's an impl class, try to find it's static member inside the class
            assert(ownerTpe.typeSymbol.isImplClass, "Not an implementation class: " + owner + " couldn't find " + name + ": " + tpe + " inside: \n" + ownerTpe.members);
            f = ownerTpe.member(name).suchThat(_.tpe =:= tpe)
//            println("\townerTpe.decls: " + ownerTpe.decls)
//            println("Looking for: " + name + ": " + tpe + " inside: " + ownerTpe.typeSymbol + "\n\tand found: " + ownerTpe.members)
          }
        }
        assert(f != NoSymbol, "could not find " + name + ": " + tpe + "inside: \n" + ownerTpe.members)
        values(index) = f
      }
      f 
    }
    
    def getNameAndType(index: Int, ownerTpe: Type): (Name, Type) = {
      if (index <= 0 || len <= index) errorBadIndex(index)
      var p = values(index).asInstanceOf[(Name, Type)]
      if (p eq null) {
        val start = starts(index)
        if (in.buf(start) != CONSTANT_NAMEANDTYPE) errorBadTag(start)
        val name = getName(in.getChar(start + 1))
        var tpe  = getType(in.getChar(start + 3))
        if (name == nme.CONSTRUCTOR)
          tpe match {
            case MethodType(formals, restpe) =>
              assert(restpe.typeSymbol == definitions.UnitClass)
              tpe = MethodType(formals, ownerTpe)
          }

        p = (name, tpe)
      }
      p
    }

    /** Return the type of a class constant entry. Since
     *  arrays are considered to be class types, they might
     *  appear as entries in 'newarray' or 'cast' opcodes.
     */
    def getClassOrArrayType(index: Int): Type = {
      if (index <= 0 || len <= index) errorBadIndex(index)
      val value = values(index)
      var c: Type = null
      if (value eq null) {
        val start = starts(index)
        if (in.buf(start) != CONSTANT_CLASS) errorBadTag(start)
        val name = getExternalName(in.getChar(start + 1))
        if (name(0) == ARRAY_TAG) {
          c = sigToType(null, name)
          values(index) = c
        } else {
          val sym = classNameToSymbol(name)
                  /*if (name.endsWith("$")) definitions.getModule(name.subName(0, name.length - 1))
                    else if (name.endsWith("$class")) definitions.getModule(name)
                    else definitions.getClass(name)*/
          values(index) = sym
          c = sym.tpe
        }
      } else c = value match {
          case tp: Type => tp
          case cls: Symbol => cls.tpe
      }
      c
    }

    def getType(index: Int): Type =
      sigToType(null, getExternalName(index))

    def getSuperClass(index: Int): Symbol =
      if (index == 0) definitions.AnyClass else getClassSymbol(index)

    def getConstant(index: Int): Constant = {
      if (index <= 0 || len <= index) errorBadIndex(index)
      var value = values(index)
      if (value eq null) {
        val start = starts(index)
        value = in.buf(start) match {
          case CONSTANT_STRING =>
            Constant(getName(in.getChar(start + 1)).toString())
          case CONSTANT_INTEGER =>
            Constant(in.getInt(start + 1))
          case CONSTANT_FLOAT =>
            Constant(in.getFloat(start + 1))
          case CONSTANT_LONG =>
            Constant(in.getLong(start + 1))
          case CONSTANT_DOUBLE =>
            Constant(in.getDouble(start + 1))
          case CONSTANT_CLASS =>
            getClassSymbol(index)
          case _ =>
            errorBadTag(start)
        }
        values(index) = value
      }
      value match {
        case  ct: Constant => ct
        case cls: Symbol   => Constant(cls.tpe)
        case arr: Type     => Constant(arr)
      }
    }

    /** Throws an exception signaling a bad constant index. */
    private def errorBadIndex(index: Int) =
      throw new RuntimeException("bad constant pool index: " + index + " at pos: " + in.bp)

    /** Throws an exception signaling a bad tag at given address. */
    private def errorBadTag(start: Int) =
      throw new RuntimeException("bad constant pool tag " + in.buf(start) + " at byte " + start)
  }


  /** Return the class symbol of the given name. */
  def classNameToSymbol(name: Name): Symbol =
    if (name.pos('.') == name.length)
      definitions.getMember(definitions.EmptyPackageClass, name.toTypeName)
    else
      definitions.getClass(name)
  
  var sawPrivateConstructor = false
  
  def parseClass() {
    val jflags = in.nextChar
    val isAnnotation = (jflags & JAVA_ACC_ANNOTATION) != 0
    var sflags = transFlags(jflags)
    if ((sflags & DEFERRED) != 0) sflags = sflags & ~DEFERRED | ABSTRACT
    val c = pool.getClassSymbol(in.nextChar)
    if (c != clazz) {
      assert(true)
      if ((clazz eq NoSymbol) && (c ne NoSymbol)) { // XXX: needed for build compiler, so can't protect with inIDE
        assert(true)
        clazz = c
      } else if (inIDE) {
        assert(true)
        Console.println("WRONG CLASS: expected: " + clazz + " found " + c)
      } else throw new IOException("class file '" + in.file + "' contains wrong " + c)
    }
    val superType = if (isAnnotation) { in.nextChar; definitions.AnnotationClass.tpe }
                    else pool.getSuperClass(in.nextChar).tpe
    val ifaceCount = in.nextChar
    var ifaces = for (i <- List.range(0, ifaceCount)) yield pool.getSuperClass(in.nextChar).tpe
    if (isAnnotation) ifaces = definitions.ClassfileAnnotationClass.tpe :: ifaces
    val parents = superType :: ifaces
    // get the class file parser to reuse scopes. 
    instanceDefs = newClassScope(clazz)
    staticDefs = newClassScope(statics)
    val classInfo = ClassInfoType(parents, instanceDefs, clazz)
    val staticInfo = ClassInfoType(List(), staticDefs, statics)

    val curbp = in.bp
    skipMembers() // fields
    skipMembers() // methods
    parseAttributes(clazz, classInfo)
    if (!isScala) {
      clazz.setFlag(sflags)
      setPrivateWithin(clazz, jflags)
      setPrivateWithin(staticModule, jflags)
      if (!hasMeta) {
        clazz.setInfo(classInfo)
      }
      statics.setInfo(staticInfo)
      staticModule.setInfo(statics.tpe)
      staticModule.setFlag(JAVA)
      staticModule.moduleClass.setFlag(JAVA)
      in.bp = curbp
      val fieldCount = in.nextChar
      for (i <- 0 until fieldCount) parseField()
      sawPrivateConstructor = false
      val methodCount = in.nextChar
      for (i <- 0 until methodCount) parseMethod()
      if (!sawPrivateConstructor &&
          (instanceDefs.lookup(nme.CONSTRUCTOR) == NoSymbol &&
           (sflags & INTERFACE) == 0))
        {
          //Console.println("adding constructor to " + clazz);//DEBUG
          instanceDefs.enter(
            clazz.newConstructor(NoPosition)
            .setFlag(clazz.flags & ConstrFlags)
            .setInfo(MethodType(List(), clazz.tpe)))

          // If the annotation has an attribute with name 'value'
          // add a constructor for it
          if (isAnnotation) {
            val value = instanceDefs.lookup(nme.value)
            if (value != NoSymbol) {
              instanceDefs.enter(
                clazz.newConstructor(NoPosition)
                .setFlag(clazz.flags & ConstrFlags)
                .setInfo(MethodType(List(value.tpe.resultType), clazz.tpe)))
            }
          }
        }
    }
  }

  def parseField() {
    val jflags = in.nextChar
    var sflags = transFlags(jflags)
    if ((sflags & FINAL) == 0) sflags = sflags | MUTABLE
    if ((sflags & PRIVATE) != 0 && !global.settings.XO.value) {
      in.skip(4); skipAttributes()
    } else {
      val name = pool.getName(in.nextChar)
      val info = pool.getType(in.nextChar)
      val sym = getOwner(jflags)
        .newValue(NoPosition, name).setFlag(sflags)
      sym.setInfo(if ((jflags & JAVA_ACC_ENUM) == 0) info else mkConstantType(Constant(sym)))
      setPrivateWithin(sym, jflags)
      parseAttributes(sym, info)