sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart

// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

library mirrors_util;

// TODO(rnystrom): Use "package:" URL (#4968).
import 'mirrors.dart';

//------------------------------------------------------------------------------
// Utility functions for using the Mirror API
//------------------------------------------------------------------------------

/**
 * Returns an iterable over the type declarations directly inheriting from
 * the declaration of this type.
 */
Iterable<ClassMirror> computeSubdeclarations(ClassMirror type) {
  type = type.originalDeclaration;
  var subtypes = <ClassMirror>[];
  type.mirrors.libraries.forEach((_, library) {
    for (ClassMirror otherType in library.classes.values) {
      var superClass = otherType.superclass;
      if (superClass != null) {
        superClass = superClass.originalDeclaration;
        if (type.library == superClass.library) {
          if (superClass == type) {
             subtypes.add(otherType);
          }
        }
      }
      final superInterfaces = otherType.superinterfaces;
      for (ClassMirror superInterface in superInterfaces) {
        superInterface = superInterface.originalDeclaration;
        if (type.library == superInterface.library) {
          if (superInterface == type) {
            subtypes.add(otherType);
          }
        }
      }
    }
  });
  return subtypes;
}

LibraryMirror findLibrary(MemberMirror member) {
  DeclarationMirror owner = member.owner;
  if (owner is LibraryMirror) {
    return owner;
  } else if (owner is TypeMirror) {
    return owner.library;
  }
  throw new Exception('Unexpected owner: ${owner}');
}

class HierarchyIterable implements Iterable<ClassMirror> {
  final bool includeType;
  final ClassMirror type;

  HierarchyIterable(this.type, {bool includeType})
      : this.includeType = includeType;

  Iterator<ClassMirror> iterator() =>
      new HierarchyIterator(type, includeType: includeType);
}

/**
 * [HierarchyIterator] iterates through the class hierarchy of the provided
 * type.
 *
 * First is the superclass relation is traversed, skipping [Object], next the
 * superinterface relation and finally is [Object] visited. The supertypes are
 * visited in breadth first order and a superinterface is visited more than once
 * if implemented through multiple supertypes.
 */
class HierarchyIterator implements Iterator<ClassMirror> {
  final Queue<ClassMirror> queue = new Queue<ClassMirror>();
  ClassMirror object;

  HierarchyIterator(ClassMirror type, {bool includeType}) {
    if (includeType) {
      queue.add(type);
    } else {
      push(type);
    }
  }

  ClassMirror push(ClassMirror type) {
    if (type.superclass != null) {
      if (type.superclass.isObject) {
        object = type.superclass;
      } else {
        queue.addFirst(type.superclass);
      }
    }
    queue.addAll(type.superinterfaces);
    return type;
  }

  ClassMirror next() {
    ClassMirror type;
    if (queue.isEmpty) {
      if (object == null) {
        throw new StateError("No more elements");
      }
      type = object;
      object = null;
      return type;
    } else {
      return push(queue.removeFirst());
    }
  }

  bool get hasNext => !queue.isEmpty || object != null;
}