Converted Observatory heap-snapshot element

runtime/observatory/lib/src/heap_snapshot/heap_snapshot.dart

Index: runtime/observatory/lib/src/heap_snapshot/heap_snapshot.dart
diff --git a/runtime/observatory/lib/src/heap_snapshot/heap_snapshot.dart b/runtime/observatory/lib/src/heap_snapshot/heap_snapshot.dart
new file mode 100644
index 0000000000000000000000000000000000000000..71f41e4f948d29e813ee2938da7d779abdcead18
--- /dev/null
+++ b/runtime/observatory/lib/src/heap_snapshot/heap_snapshot.dart
@@ -0,0 +1,226 @@
+// Copyright (c) 2016, 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.
+
+part of heap_snapshot;
+
+class HeapSnapshot implements M.HeapSnapshot {
+  ObjectGraph graph;
+  DateTime timestamp;
+  int get objects => graph.vertexCount;
+  int get references => graph.edgeCount;
+  int get size => graph.size;
+  HeapSnapshotDominatorNode dominatorTree;
+  List<MergedVertex> classReferences;
+
+  static Future sleep([Duration duration = const Duration(microseconds: 0)]) {
+    final Completer completer = new Completer();
+    new Timer(duration, () => completer.complete() );
+    return completer.future;
+  }
+
+  Stream<List> loadProgress(S.Isolate isolate, S.RawHeapSnapshot raw) {
+    final progress = new StreamController<List>.broadcast();
+    progress.add(['', 0.0]);
+    graph = new ObjectGraph(raw.chunks, raw.count);
+    var signal = (String description, double p) {
+      progress.add([description, p]);
+      return sleep();
+    };
+    (() async {
+      timestamp = new DateTime.now();
+      final stream = graph.process();
+      stream.listen((status) {
+        status[1] /= 2.0;
+        progress.add(status);
+      });
+      await stream.last;
+      dominatorTree = new HeapSnapshotDominatorNode(isolate, graph.root);
+      classReferences = await buildMergedVertices(isolate, graph, signal);
+      progress.close();
+    }());
+    return progress.stream;
+  }
+
+  Future<List<MergedVertex>> buildMergedVertices(S.Isolate isolate,
+                                                 ObjectGraph graph,
+                                                 signal) async {
+    final cidToMergedVertex = {};
+
+    int count = 0;
+    final Stopwatch watch = new Stopwatch();
+    watch.start();
+    var needToUpdate = () {
+      count++;
+      if (((count % 256) == 0) && (watch.elapsedMilliseconds > 16)) {
+        watch.reset();
+        return true;
+      }
+      return false;
+    };
+    final length = graph.vertices.length;
+    for (final vertex in graph.vertices) {
+      if (vertex.vmCid == 0) {
+        continue;
+      }
+      if (needToUpdate()) {
+        await signal('', count * 50.0 / length + 50);
+      }
+      final cid = vertex.vmCid;
+      MergedVertex source = cidToMergedVertex[cid];
+      if (source == null) {
+        cidToMergedVertex[cid] = source = new MergedVertex(isolate, cid);
+      }
+
+      source.instances++;
+      source.shallowSize += vertex.shallowSize ?? 0;
+
+      for (final vertex2 in vertex.successors) {
+        if (vertex2.vmCid == 0) {
+          continue;
+        }
+        final cid2 = vertex2.vmCid;
+        MergedEdge edge = source.outgoingEdges[cid2];
+        if (edge == null) {
+          MergedVertex target = cidToMergedVertex[cid2];
+          if (target == null) {
+            cidToMergedVertex[cid2] = target = new MergedVertex(isolate, cid2);
+          }
+          edge = new MergedEdge(source, target);
+          source.outgoingEdges[cid2] = edge;
+          target.incomingEdges.add(edge);
+        }
+        edge.count++;
+        // An over-estimate if there are multiple references to the same object.
+        edge.shallowSize += vertex2.shallowSize ?? 0;
+      }
+    }
+    return cidToMergedVertex.values.toList();
+  }
+
+  List<Future<S.ServiceObject>> getMostRetained(S.Isolate isolate,
+                                                {int classId, int limit}) {
+    var result = [];
+    for (ObjectVertex v in graph.getMostRetained(classId: classId,
+                                                 limit: limit)) {
+      result.add(isolate.getObjectByAddress(v.address)
+                        .then((S.ServiceObject obj) {
+        if (obj is S.HeapObject) {
+          obj.retainedSize = v.retainedSize;
+        } else {
+          print("${obj.runtimeType} should be a HeapObject");
+        }
+        return obj;
+      }));
+    }
+    return result;
+  }
+}
+
+class HeapSnapshotDominatorNode implements M.HeapSnapshotDominatorNode {
+  final ObjectVertex v;
+  final S.Isolate isolate;
+  S.HeapObject _preloaded;
+
+  Future<S.HeapObject> get object {
+    if (_preloaded != null) {
+      return new Future.value(_preloaded);
+    } else {
+      return isolate.getObjectByAddress(v.address).then((S.HeapObject obj) {
+        return _preloaded = obj;
+      });
+    }
+  }
+  Iterable<HeapSnapshotDominatorNode> _children;
+  Iterable<HeapSnapshotDominatorNode> get children {
+    if (_children != null) {
+      return _children;
+    } else {
+      return _children = new List.unmodifiable(
+        v.dominatorTreeChildren().map((v) {
+          return new HeapSnapshotDominatorNode(isolate, v);
+        })
+      );
+    }
+  }
+  int get retainedSize => v.retainedSize;
+  int get shallowSize => v.shallowSize;
+
+  HeapSnapshotDominatorNode(S.Isolate isolate, ObjectVertex vertex)
+    : isolate = isolate,
+      v = vertex;
+}
+
+class MergedEdge {
+  final MergedVertex sourceVertex;
+  final MergedVertex targetVertex;
+  int count = 0;
+  int shallowSize = 0;
+  int retainedSize = 0;
+
+  MergedEdge(this.sourceVertex, this.targetVertex);
+}
+
+class MergedVertex implements M.HeapSnapshotClassReferences {
+  final int cid;
+  final S.Isolate isolate;
+  S.Class get clazz => isolate.getClassByCid(cid);
+  int instances = 0;
+  int shallowSize = 0;
+  int retainedSize = 0;
+
+  List<MergedEdge> incomingEdges = new List<MergedEdge>();
+  Map<int, MergedEdge> outgoingEdges = new Map<int, MergedEdge>();
+
+  Iterable<HeapSnapshotClassInbound> _inbounds;
+  Iterable<HeapSnapshotClassInbound> get inbounds {
+    if (_inbounds != null) {
+      return _inbounds;
+    } else {
+      return _inbounds = new List.unmodifiable(
+        incomingEdges.map((edge) {
+          return new HeapSnapshotClassInbound(this, edge);
+        })
+      );
+    }
+  }
+
+  Iterable<HeapSnapshotClassOutbound> _outbounds;
+  Iterable<HeapSnapshotClassOutbound> get outbounds {
+    if (_outbounds != null) {
+      return _outbounds;
+    } else {
+      return _outbounds = new List.unmodifiable(
+        outgoingEdges.values.map((edge) {
+          return new HeapSnapshotClassInbound(this, edge);
+        })
+      );
+    }
+  }
+
+  MergedVertex(this.isolate, this.cid);
+}
+
+class HeapSnapshotClassInbound implements M.HeapSnapshotClassInbound {
+  final MergedVertex vertex;
+  final MergedEdge edge;
+  S.Class get source => edge.sourceVertex != vertex ? edge.sourceVertex.clazz
+                                                    : edge.targetVertex.clazz;
+  int get count => edge.count;
+  int get shallowSize => edge.shallowSize;
+  int get retainedSize => edge.retainedSize;
+
+  HeapSnapshotClassInbound(this.vertex, this.edge);
+}
+
+class HeapSnapshotClassOutbound implements M.HeapSnapshotClassOutbound {
+  final MergedVertex vertex;
+  final MergedEdge edge;
+  S.Class get target => edge.sourceVertex != vertex ? edge.sourceVertex.clazz
+                                                    : edge.targetVertex.clazz;
+  int get count => edge.count;
+  int get shallowSize => edge.shallowSize;
+  int get retainedSize => edge.retainedSize;
+
+  HeapSnapshotClassOutbound(this.vertex, this.edge);
+}