Keep track of where objects are being referenced in memory status page

pkg/analysis_server/lib/src/status/get_handler.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 analysis_server.src.status.get_handler;
 
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:math';
@@ skipping 1642 matching lines @@
   }
 
   void _returnMemoryUsage(HttpRequest request) {
     _writeResponse(request, (StringBuffer buffer) {
       _writePage(buffer, 'Analysis Server - Memory Use', [],
           (StringBuffer buffer) {
         AnalysisServer server = _server.analysisServer;
         MemoryUseData data = new MemoryUseData();
         data.processAnalysisServer(server);
         Map<Type, Set> instances = data.instances;
-        List<Type> types = instances.keys.toList();
-        types.sort((Type left, Type right) =>
+        List<Type> instanceTypes = instances.keys.toList();
+        instanceTypes.sort((Type left, Type right) =>
+            left.toString().compareTo(right.toString()));
+        Map<Type, Set> ownerMap = data.ownerMap;
+        List<Type> ownerTypes = ownerMap.keys.toList();
+        ownerTypes.sort((Type left, Type right) =>
             left.toString().compareTo(right.toString()));
 
-        buffer.write('<h3>Instance Counts (reachable from contexts)</h3>');
-        buffer.write('<table>');
-        _writeRow(buffer, ['Count', 'Class name'], header: true);
-        types.forEach((Type type) {
-          _writeRow(buffer, [instances[type].length, type],
-              classes: ['right', null]);
-        });
-        buffer.write('</table>');
-
-        void writeCountMap(String title, Map<Type, int> counts) {
-          List<Type> classNames = counts.keys.toList();
-          classNames.sort((Type left, Type right) =>
-              left.toString().compareTo(right.toString()));
-
-          buffer.write('<h3>$title</h3>');
+        _writeTwoColumns(buffer, (StringBuffer buffer) {
+          buffer.write('<h3>Instance Counts (reachable from contexts)</h3>');
           buffer.write('<table>');
           _writeRow(buffer, ['Count', 'Class name'], header: true);
-          classNames.forEach((Type type) {
-            _writeRow(buffer, [counts[type], type], classes: ['right', null]);
+          instanceTypes.forEach((Type type) {
+            _writeRow(buffer, [instances[type].length, type],
+                classes: ['right', null]);
           });
           buffer.write('</table>');
-        }
-        writeCountMap('Directly Held AST Nodes', data.directNodeCounts);
-        writeCountMap('Indirectly Held AST Nodes', data.indirectNodeCounts);
-        writeCountMap('Directly Held Elements', data.elementCounts);
 
-        buffer.write('<h3>Other Data</h3>');
-        buffer.write('<p>');
-        buffer.write(data.uniqueTargetedResults.length);
-        buffer.write(' non-equal TargetedResults</p>');
-        buffer.write('<p>');
-        buffer.write(data.uniqueLSUs.length);
-        buffer.write(' non-equal LibrarySpecificUnits</p>');
+          buffer.write(
+              '<h3>Ownership (which classes of objects hold on to others)</h3>');
+          buffer.write('<table>');
+          _writeRow(buffer, ['Referenced Type', 'Referencing Types'],
+              header: true);
+          ownerTypes.forEach((Type type) {
+            List<String> referencingTypes =
+                ownerMap[type].map((Type type) => type.toString()).toList();
+            referencingTypes.sort();
+            _writeRow(buffer, [type, referencingTypes.join('<br>')]);
+          });
+          buffer.write('</table>');
+
+          buffer.write('<h3>Other Data</h3>');
+          buffer.write('<p>');
+          buffer.write(data.uniqueTargetedResults.length);
+          buffer.write(' non-equal TargetedResults</p>');
+          buffer.write('<p>');
+          buffer.write(data.uniqueLSUs.length);
+          buffer.write(' non-equal LibrarySpecificUnits</p>');
+          int count = data.mismatchedTargets.length;
+          buffer.write('<p>');
+          buffer.write(count);
+          buffer.write(' mismatched targets</p>');
+          if (count < 100) {
+            for (AnalysisTarget target in data.mismatchedTargets) {
+              buffer.write(target);
+              buffer.write('<br>');
+            }
+          }
+        }, (StringBuffer buffer) {
+          void writeCountMap(String title, Map<Type, int> counts) {
+            List<Type> classNames = counts.keys.toList();
+            classNames.sort((Type left, Type right) =>
+                left.toString().compareTo(right.toString()));
+
+            buffer.write('<h3>$title</h3>');
+            buffer.write('<table>');
+            _writeRow(buffer, ['Count', 'Class name'], header: true);
+            classNames.forEach((Type type) {
+              _writeRow(buffer, [counts[type], type], classes: ['right', null]);
+            });
+            buffer.write('</table>');
+          }
+          writeCountMap('Directly Held AST Nodes', data.directNodeCounts);
+          writeCountMap('Indirectly Held AST Nodes', data.indirectNodeCounts);
+          writeCountMap('Directly Held Elements', data.elementCounts);
+        });
       });
     });
   }
 
   void _returnOverlayContents(HttpRequest request) {
     String path = request.requestedUri.queryParameters[PATH_PARAM];
     if (path == null) {
       return _returnFailure(request, 'Query parameter $PATH_PARAM required');
     }
     String contents = _overlayContents[path];
@@ skipping 630 matching lines @@
     buffer.write(
         'h3 {background-color: #DDDDDD; margin-top: 0em; margin-bottom: 0em;}');
     buffer.write('p {margin-top: 0.5em; margin-bottom: 0.5em;}');
     buffer.write(
         'p.commentary {margin-top: 1em; margin-bottom: 1em; margin-left: 2em; font-style: italic;}');
 //    response.write('span.error {text-decoration-line: underline; text-decoration-color: red; text-decoration-style: wavy;}');
     buffer.write(
         'table.column {border: 0px solid black; width: 100%; table-layout: fixed;}');
     buffer.write('td.column {vertical-align: top; width: 50%;}');
     buffer.write('td.right {text-align: right;}');
-    buffer.write('th {text-align: left;}');
+    buffer.write('th {text-align: left; vertical-align:top;}');
+    buffer.write('tr {vertical-align:top;}');
     buffer.write('</style>');
     buffer.write('</head>');
 
     buffer.write('<body>');
     buffer.write(
         '<h2>$title <small><small>(as of $time on $date)</small></small></h2>');
     if (subtitles != null && subtitles.isNotEmpty) {
       buffer.write('<blockquote>');
       bool first = true;
       for (String subtitle in subtitles) {
@@ skipping 348 matching lines @@
    */
   static String makeLink(
       String path, Map<String, String> params, String innerHtml,
       [bool hasError = false]) {
     Uri uri = new Uri(path: path, queryParameters: params);
     String href = HTML_ESCAPE.convert(uri.toString());
     String classAttribute = hasError ? ' class="error"' : '';
     return '<a href="$href"$classAttribute>$innerHtml</a>';
   }
 }