fix race condition when recording computeCache performance

pkg/analysis_server/lib/src/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.get_handler;
 
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:math';
@@ skipping 297 matching lines @@
     }
     String sourceUri = request.uri.queryParameters[SOURCE_QUERY_PARAM];
     if (sourceUri == null) {
       return _returnFailure(
           request,
           'Query parameter $SOURCE_QUERY_PARAM required');
     }
 
     List<Folder> allContexts = <Folder>[];
     Map<Folder, SourceEntry> entryMap = new HashMap<Folder, SourceEntry>();
-    analysisServer.folderMap.forEach((Folder folder, AnalysisContextImpl context) {
+    analysisServer.folderMap.forEach(
+        (Folder folder, AnalysisContextImpl context) {
       Source source = context.sourceFactory.forUri(sourceUri);
       if (source != null) {
         SourceEntry entry = context.getReadableSourceEntryOrNull(source);
         if (entry != null) {
           allContexts.add(folder);
           entryMap[folder] = entry;
         }
       }
     });
-    allContexts.sort((Folder firstFolder, Folder secondFolder) => firstFolder.path.compareTo(secondFolder.path));
+    allContexts.sort(
+        (Folder firstFolder, Folder secondFolder) =>
+            firstFolder.path.compareTo(secondFolder.path));
     AnalysisContextImpl context = analysisServer.folderMap[folder];
 
     _writeResponse(request, (StringBuffer buffer) {
       _writePage(
           buffer,
           'Analysis Server - Cache Entry',
           ['Context: $contextFilter', 'File: $sourceUri'],
           (HttpResponse) {
         buffer.write('<h3>Analyzing Contexts</h3><p>');
         bool first = true;
         allContexts.forEach((Folder folder) {
           if (first) {
             first = false;
           } else {
             buffer.write('<br>');
           }
-          AnalysisContextImpl analyzingContext = analysisServer.folderMap[folder];
+          AnalysisContextImpl analyzingContext =
+              analysisServer.folderMap[folder];
           if (analyzingContext == context) {
             buffer.write(folder.path);
           } else {
             buffer.write(_makeLink(CACHE_ENTRY_PATH, {
               CONTEXT_QUERY_PARAM: folder.path,
               SOURCE_QUERY_PARAM: sourceUri
             }, HTML_ESCAPE.convert(folder.path)));
           }
           if (entryMap[folder].explicitlyAdded) {
             buffer.write(' (explicit)');
@@ skipping 120 matching lines @@
     });
   }
 
   /**
    * Return a response displaying code completion information.
    */
   void _returnCompletionInfo(HttpRequest request) {
     String value = request.requestedUri.queryParameters['index'];
     int index = value != null ? int.parse(value, onError: (_) => 0) : 0;
     _writeResponse(request, (StringBuffer buffer) {
-      _writePage(buffer, 'Analysis Server - Completion Stats', [], (StringBuffer buffer) {
+      _writePage(
+          buffer,
+          'Analysis Server - Completion Stats',
+          [],
+          (StringBuffer buffer) {
         _writeCompletionPerformanceDetail(buffer, index);
         _writeCompletionPerformanceList(buffer);
       });
     });
   }
 
   /**
    * Return a response containing information about a single source file in the
    * cache.
    */
@@ skipping 382 matching lines @@
       List<CompletionPerformance> list = handler.performanceList;
       if (list != null && list.isNotEmpty) {
         performance = list[max(0, min(list.length - 1, index))];
       }
     }
     if (performance == null) {
       buffer.write('<h3>Completion Performance Detail</h3>');
       buffer.write('<p>No completions yet</p>');
       return;
     }
-    buffer.write(
-        '<h3>Completion Performance Detail - ${performance.startTimeAndMs}</h3>');
+    buffer.write('<h3>Completion Performance Detail</h3>');
+    buffer.write('<p>${performance.startTimeAndMs} for ${performance.source}');
     buffer.write('<table>');
     _writeRow(buffer, ['Elapsed', '', 'Operation'], header: true);
     performance.operations.forEach((OperationPerformance op) {
       String elapsed = op.elapsed != null ? op.elapsed.toString() : '???';
       _writeRow(buffer, [elapsed, '&nbsp;&nbsp;', op.name]);
     });
-    if (handler.priorityChangedPerformance == null) {
-      buffer.write('<p>No priorityChanged caching</p>');
+    buffer.write('</table>');
+    buffer.write('<p><b>Compute Cache Performance</b>: ');
+    if (handler.computeCachePerformance == null) {
+      buffer.write('none');
     } else {
-      int len = handler.priorityChangedPerformance.operations.length;
-      if (len > 0) {
-        var op = handler.priorityChangedPerformance.operations[len - 1];
-        if (op != null) {
-          _writeRow(buffer, ['&nbsp;', '&nbsp;', '&nbsp;']);
-          String elapsed = op.elapsed != null ? op.elapsed.toString() : '???';
-          _writeRow(buffer, [elapsed, '&nbsp;&nbsp;', op.name]);
-        }
-      }
+      int elapsed = handler.computeCachePerformance.elapsedInMilliseconds;
+      Source source = handler.computeCachePerformance.source;
+      buffer.write(' $elapsed ms for $source');
     }
-    buffer.write('</table>');
+    buffer.write('</p>');
   }
 
   /**
    * Write a table showing summary information for the last several
    * completion requests to the given [buffer] object.
    */
   void _writeCompletionPerformanceList(StringBuffer buffer) {
     CompletionDomainHandler handler = _completionDomainHandler;
-    buffer.write('<h3>Completion Performance</h3>');
+    buffer.write('<h3>Completion Performance List</h3>');
     if (handler == null) {
       return;
     }
     buffer.write('<table>');
     _writeRow(
         buffer,
         [
             'Start Time',
             '',
             'First (ms)',
@@ skipping 257 matching lines @@
     } finally {
       response.close();
     }
   }
 
   /**
    * Write a single row within a table to the given [buffer]. The row will have
    * one cell for each of the [columns], and will be a header row if [header] is
    * `true`.
    */
-  void _writeRow(StringBuffer buffer, List<Object> columns, {bool header:
-      false, List<String> classes}) {
+  void _writeRow(StringBuffer buffer, List<Object> columns, {bool header: false,
+      List<String> classes}) {
     buffer.write('<tr>');
     int count = columns.length;
     int maxClassIndex = classes == null ? 0 : classes.length - 1;
     for (int i = 0; i < count; i++) {
       String classAttribute = '';
       if (classes != null) {
         String className = classes[min(i, maxClassIndex)];
         if (className != null) {
           classAttribute = ' class="$className"';
         }
@@ skipping 171 matching lines @@
     } else if (value is Element) {
       String link =
           _makeLink(ELEMENT_PATH, linkParameters, value.runtimeType.toString());
       buffer.write('<i>$link</i>');
     } else {
       buffer.write(HTML_ESCAPE.convert(value.toString()));
       buffer.write(' <i>(${value.runtimeType.toString()})</i>');
     }
   }
 }