/**
   * Constructor. Initializes the ClassDirectiveProcessor and its associated AET data structures.
   *
   * @param node - the AST that starts the class' definition in source; used for diagnostics.
   * @param class_definition - the class' definition
   * @param enclosing_scope - the immediately enclosing lexical scope.
   * @param emitter - the active ABC emitter.
   */
  ClassDirectiveProcessor(
      ICommonClassNode node,
      ClassDefinition class_definition,
      LexicalScope enclosing_scope,
      IABCVisitor emitter) {
    super(enclosing_scope.getProblems());

    this.emitter = emitter;
    this.definitionSource = node;
    assert (this.definitionSource != null) : "Class definition AST must be provided.";

    this.classScope = enclosing_scope.pushFrame();
    this.classStaticScope = enclosing_scope.pushFrame();

    if (node.getNodeID() == ASTNodeID.ClassID) {
      classScope.setInitialControlFlowRegionNode(((ClassNode) node).getScopedNode());
      classStaticScope.setInitialControlFlowRegionNode(((ClassNode) node).getScopedNode());
    }

    ICompilerProject project = classScope.getProject();

    // Set the class Name.
    this.classDefinition = class_definition;
    this.className = classDefinition.getMName(project);
    iinfo.name = className;

    // Check for a duplicate class name.
    switch (SemanticUtils.getMultiDefinitionType(this.classDefinition, project)) {
      case AMBIGUOUS:
        classScope.addProblem(
            new DuplicateClassDefinitionProblem(node, class_definition.getBaseName()));
        break;
      case NONE:
        break;
      default:
        assert false; // I don't think classes can have other type of multiple definitions
    }

    if (node instanceof BaseDefinitionNode) // test doesn't work for MXML, which is OK.
    {
      BaseDefinitionNode n = (BaseDefinitionNode) node;
      SemanticUtils.checkScopedToDefaultNamespaceProblem(classScope, n, classDefinition, null);
    }
    // Resolve the super class, checking that it exists,
    // that it is a class rather than an interface,
    // that it isn't final, and that it isn't the same as this class.
    ClassDefinition superclassDefinition =
        SemanticUtils.resolveBaseClass(node, class_definition, project, classScope.getProblems());

    // Check that the superclass isn't a forward reference, but only need to do this if both
    // definitions come from the same containing source.  getContainingFilePath() returns the file
    // from the ASFileScope, so no need to worry about included files.
    if (!classDefinition.isGeneratedEmbedClass()
        && classDefinition
            .getContainingFilePath()
            .equals(superclassDefinition.getContainingFilePath())) {
      // If the absolute offset in the class is less than the
      // offset of the super class, it must be a forward reference in the file
      int classOffset = classDefinition.getAbsoluteStart();
      int superClassOffset = superclassDefinition.getAbsoluteEnd();
      if (classOffset < superClassOffset)
        classScope.addProblem(
            new ForwardReferenceToBaseClassProblem(node, superclassDefinition.getQualifiedName()));
    }

    // Set the superclass Name.
    this.superclassName = superclassDefinition.getMName(project);
    iinfo.superName = superclassName;

    // Resolve the interfaces.
    IInterfaceDefinition[] interfaces =
        classDefinition.resolveImplementedInterfaces(project, classScope.getProblems());

    // Set the interface Names.
    int n_interfaces = interfaces.length;
    ArrayList<Name> interface_names = new ArrayList<Name>(n_interfaces);
    for (int i = 0; i < n_interfaces; i++) {
      InterfaceDefinition idef = (InterfaceDefinition) interfaces[i];
      if (idef != null) {
        Name interfaceName = ((InterfaceDefinition) interfaces[i]).getMName(project);
        interface_names.add(interfaceName);
      }
    }
    iinfo.interfaceNames = interface_names.toArray(new Name[interface_names.size()]);

    // Set the flags corresponding to 'final' and 'dynamic'.
    if (classDefinition.isFinal()) iinfo.flags |= ABCConstants.CLASS_FLAG_final;
    if (!classDefinition.isDynamic()) iinfo.flags |= ABCConstants.CLASS_FLAG_sealed;

    iinfo.protectedNs =
        ((NamespaceDefinition) classDefinition.getProtectedNamespaceReference()).getAETNamespace();

    this.cv = emitter.visitClass(iinfo, cinfo);
    cv.visit();

    this.itraits = cv.visitInstanceTraits();
    this.ctraits = cv.visitClassTraits();

    this.classScope.traitsVisitor = this.itraits;
    this.classStaticScope.traitsVisitor = this.ctraits;

    // Build an array of the names of all the ancestor classes.
    ArrayList<Name> ancestorClassNames = new ArrayList<Name>();

    // Walk the superclass chain, starting with this class
    // and (unless there are problems) ending with Object.
    // This will accomplish three things:
    // - find loops;
    // - build the array of names of ancestor classes;
    // - set the needsProtected flag if this class or any of its ancestor classes needs it.

    boolean needsProtected = false;

    //  Remember the most recently examined class in case there's a cycle in the superclass
    //  chain, in which case we'll need it to issue a diagnostic.
    ClassDefinition c = null;

    IClassDefinition.IClassIterator classIterator = classDefinition.classIterator(project, true);

    while (classIterator.hasNext()) {
      c = (ClassDefinition) classIterator.next();
      needsProtected |= c.getOwnNeedsProtected();
      if (c != classDefinition) ancestorClassNames.add(c.getMName(project));
    }

    // Report a loop in the superclass chain, such as A extends B and B extends A.
    // Note: A extends A was found previously by SemanticUtils.resolveBaseClass().
    if (classIterator.foundLoop())
      classScope.addProblem(new CircularTypeReferenceProblem(c, c.getQualifiedName()));

    // In the case of class A extends A, ancestorClassNames will be empty at this point.
    // Change it to be Object to prevent "Warning: Stack underflow" in the script init code below.
    if (ancestorClassNames.isEmpty()) {
      ClassDefinition objectDefinition =
          (ClassDefinition) project.getBuiltinType(IASLanguageConstants.BuiltinType.OBJECT);
      ancestorClassNames.add(objectDefinition.getMName(project));
    }

    // If this class or any of its ancestor classes needs the protected flag set, set it.
    if (needsProtected) iinfo.flags |= ABCConstants.CLASS_FLAG_protected;

    // Add the class initialization logic to the script init.
    // For class B extends A, where class A extends Object, this looks like
    // getscopeobject
    // findpropstrict Object
    // getproperty Object
    // pushscope
    // findpropstrict A
    // getproperty A
    // dup
    // pushscope
    // newclass
    // popscope
    // popscope
    // initproperty B
    InstructionList initInstructions = this.classScope.getInitInstructions();
    initInstructions.addInstruction(OP_getscopeobject, 0);

    // Push ancestor classes onto the scope stack.
    for (int i = ancestorClassNames.size() - 1; i >= 0; i--) {
      Name ancestorClassName = ancestorClassNames.get(i);
      initInstructions.addInstruction(OP_getlex, ancestorClassName);
      // The newclass instruction below also needs the superclass on the stack, so dup it
      if (i == 0) initInstructions.addInstruction(OP_dup);
      initInstructions.addInstruction(OP_pushscope);
    }

    initInstructions.addInstruction(OP_newclass, cinfo);

    for (int i = 0; i < ancestorClassNames.size(); i++)
      initInstructions.addInstruction(OP_popscope);

    initInstructions.addInstruction(OP_initproperty, className);

    implementedInterfaceSemanticChecks(class_definition);

    processResourceBundles(class_definition, project, classScope.getProblems());
  }