Revert "Build Observatory with runtime"

runtime/observatory/lib/object_graph.dart

-// Copyright (c) 2014, 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 object_graph;
-
-import 'dart:typed_data';
-
-import 'dominator_tree.dart';
-
-// Port of dart::ReadStream from vm/datastream.h.
-class ReadStream {
-  int _cur = 0;
-  final ByteData _data;
-  
-  ReadStream(this._data);
-  
-  int get pendingBytes => _data.lengthInBytes - _cur;
-  
-  int readUnsigned() {
-    int result = 0;
-    int shift = 0;
-    while (_data.getUint8(_cur) <= maxUnsignedDataPerByte) {
-      result |= _data.getUint8(_cur) << shift;
-      shift += dataBitsPerByte;
-      ++_cur;
-    }
-    result |= (_data.getUint8(_cur) & byteMask) << shift;
-    ++_cur;
-    return result;
-  }
-
-  static const int dataBitsPerByte = 7;
-  static const int byteMask = (1 << dataBitsPerByte) - 1;
-  static const int maxUnsignedDataPerByte = byteMask;
-}
-
-class ObjectVertex {
-  // Never null. The isolate root has id 0.
-  final int _id;
-  // null for VM-heap objects.
-  int _shallowSize;
-  int get shallowSize => _shallowSize;
-  int _retainedSize;
-  int get retainedSize => _retainedSize;
-  // null for VM-heap objects.
-  int _classId;
-  int get classId => _classId;
-  final List<ObjectVertex> succ = new List<ObjectVertex>();
-  ObjectVertex(this._id) : _retainedSize = 0;
-  String toString() => '$_id,$_shallowSize,$succ';
-}
-
-// See implementation of ObjectGraph::Serialize for format.
-class ObjectGraph {
-  final Map<int, ObjectVertex> _idToVertex = new Map<int, ObjectVertex>();
-
-  ObjectVertex _asVertex(int id) {
-    return _idToVertex.putIfAbsent(id, () => new ObjectVertex(id));
-  }
-
-  void _addFrom(ReadStream stream) {
-    ObjectVertex obj = _asVertex(stream.readUnsigned());
-    obj._shallowSize = stream.readUnsigned();
-    obj._classId = stream.readUnsigned();
-    int last = stream.readUnsigned();
-    while (last != 0) {
-      obj.succ.add(_asVertex(last));
-      last = stream.readUnsigned();
-    }
-  }
-
-  ObjectGraph(ReadStream reader) {
-    while (reader.pendingBytes > 0) {
-      _addFrom(reader);
-    }
-    _computeRetainedSizes();
-  }
-
-  Iterable<ObjectVertex> get vertices => _idToVertex.values;
-
-  ObjectVertex get root => _asVertex(0);
-  
-  void _computeRetainedSizes() {
-    // The retained size for an object is the sum of the shallow sizes of
-    // all its descendants in the dominator tree (including itself).
-    var d = new Dominator();
-    for (ObjectVertex u in vertices) {
-      if (u.shallowSize != null) {
-        u._retainedSize = u.shallowSize;
-        d.addEdges(u, u.succ.where((ObjectVertex v) => v.shallowSize != null));
-      }
-    }
-    d.computeDominatorTree(root);
-    // Compute all retained sizes "bottom up", starting from the leaves.
-    // Keep track of number of remaining children of each vertex.
-    var degree = new Map<ObjectVertex, int>();
-    for (ObjectVertex u in vertices) {
-      var v = d.dominator(u);
-      if (v != null) {
-        degree[v] = 1 + degree.putIfAbsent(v, () => 0);
-      }
-    }
-    var leaves = new List<ObjectVertex>();
-    for (ObjectVertex u in vertices) {
-      if (!degree.containsKey(u)) {
-        leaves.add(u);
-      }
-    }
-    while (!leaves.isEmpty) {
-      var v = leaves.removeLast();
-      var u = d.dominator(v);
-      if (u == null) continue;
-      u._retainedSize += v._retainedSize;
-      if (--degree[u] == 0) {
-        leaves.add(u);
-      }
-    }
-  }
-}