Add a new Analysis Server option '--new-analysis-driver-log'.

pkg/analysis_server/lib/src/analysis_server.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;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core';
 import 'dart:io' as io;
@@ skipping 348 matching lines @@
     _performance = performanceDuringStartup;
     defaultContextOptions.incremental = true;
     defaultContextOptions.incrementalApi =
         options.enableIncrementalResolutionApi;
     defaultContextOptions.incrementalValidation =
         options.enableIncrementalResolutionValidation;
     defaultContextOptions.finerGrainedInvalidation =
         options.finerGrainedInvalidation;
     defaultContextOptions.generateImplicitErrors = false;
     operationQueue = new ServerOperationQueue();
-    _analysisPerformanceLogger = new nd.PerformanceLog(io.stdout);
+
+    {
+      String name = options.newAnalysisDriverLog;
+      StringSink sink = new _NullStringSink();
+      if (name != null) {
+        if (name == 'stdout') {
+          sink = io.stdout;
+        } else if (name.startsWith('file:')) {
+          String path = name.substring('file:'.length);
+          sink = new io.File(path).openWrite(mode: io.FileMode.APPEND);
+        }
+      }
+      _analysisPerformanceLogger = new nd.PerformanceLog(sink);
+    }
     if (resourceProvider is PhysicalResourceProvider) {
       byteStore = new MemoryCachingByteStore(
           new FileByteStore(
               resourceProvider.getStateLocation('.analysis-driver').path,
               1024 * 1024 * 1024 /*1 GiB*/),
           64 * 1024 * 1024 /*64 MiB*/);
     } else {
       byteStore = new MemoryByteStore();
     }
     analysisDriverScheduler =
         new nd.AnalysisDriverScheduler(_analysisPerformanceLogger);
     analysisDriverScheduler.status.listen(sendStatusNotificationNew);
     analysisDriverScheduler.start();
+
     if (useSingleContextManager) {
       contextManager = new SingleContextManager(resourceProvider, sdkManager,
           packageResolverProvider, analyzedFilesGlobs, defaultContextOptions);
     } else {
       contextManager = new ContextManagerImpl(
           resourceProvider,
           sdkManager,
           packageResolverProvider,
           packageMapProvider,
           analyzedFilesGlobs,
@@ skipping 1332 matching lines @@
 class AnalysisServerOptions {
   bool enableIncrementalResolutionApi = false;
   bool enableIncrementalResolutionValidation = false;
   bool enableNewAnalysisDriver = false;
   bool enablePubSummaryManager = false;
   bool finerGrainedInvalidation = false;
   bool noErrorNotification = false;
   bool noIndex = false;
   bool useAnalysisHighlight2 = false;
   String fileReadMode = 'as-is';
+  String newAnalysisDriverLog;
 }
 
 /**
  * Information about a file - an [AnalysisContext] that analyses the file,
  * and the [Source] representing the file in this context.
  */
 class ContextSourcePair {
   /**
    * A context that analysis the file.
    * May be `null` if the file is not analyzed by any context.
@@ skipping 316 matching lines @@
   /**
    * The [PerformanceTag] for time spent in server request handlers.
    */
   static PerformanceTag serverRequests = new PerformanceTag('serverRequests');
 
   /**
    * The [PerformanceTag] for time spent in split store microtasks.
    */
   static PerformanceTag splitStore = new PerformanceTag('splitStore');
 }
+
+class _NullStringSink implements StringSink {
+  void write(Object obj) {}
+  void writeAll(Iterable objects, [String separator = ""]) {}
+  void writeCharCode(int charCode) {}
+  void writeln([Object obj = ""]) {}
+}