[analyzer] Report memory usage on Windows too

Change-Id: I6a31370c51e40a9593f8875d365a43d9f4111aaf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/275660
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>

pkg/analysis_server/lib/src/status/diagnostics.dart

@@ -1065,8 +1065,10 @@ class MemoryAndCpuPage extends DiagnosticPageWithNav {
     var serviceProtocolInfo = await developer.Service.getInfo();
 
     if (usage != null) {
-      buf.writeln(
-          writeOption('CPU', printPercentage(usage.cpuPercentage / 100.0)));
+      var cpuPercentage = usage.cpuPercentage;
+      if (cpuPercentage != null) {
+        buf.writeln(writeOption('CPU', printPercentage(cpuPercentage / 100.0)));
+      }
       buf.writeln(writeOption('Memory', '${usage.memoryMB.round()} MB'));
 
       h3('VM');

pkg/analysis_server/lib/src/utilities/profiling.dart

@@ -2,6 +2,7 @@
 // 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.
 
+import 'dart:convert';
 import 'dart:io';
 
 /// A class that can return memory and cpu usage information for a given
@@ -19,6 +20,10 @@ abstract class ProcessProfiler {
       return _PosixProcessProfiler();
     }
 
+    if (Platform.isWindows) {
+      return _WindowsProcessProfiler();
+    }
+
     // Not a supported platform.
     return null;
   }
@@ -27,7 +32,7 @@ abstract class ProcessProfiler {
 class UsageInfo {
   /// A number between 0.0 and 100.0 * the number of host CPUs (but typically
   /// never more than slightly above 100.0).
-  final double cpuPercentage;
+  final double? cpuPercentage;
 
   /// The process memory usage in kilobytes.
   final int memoryKB;
@@ -37,7 +42,12 @@ class UsageInfo {
   double get memoryMB => memoryKB / 1024;
 
   @override
-  String toString() => '$cpuPercentage% ${memoryMB.toStringAsFixed(1)}MB';
+  String toString() {
+    if (cpuPercentage != null) {
+      return '$cpuPercentage% ${memoryMB.toStringAsFixed(1)}MB';
+    }
+    return '${memoryMB.toStringAsFixed(1)}MB';
+  }
 }
 
 class _PosixProcessProfiler extends ProcessProfiler {
@@ -74,3 +84,44 @@ class _PosixProcessProfiler extends ProcessProfiler {
     }
   }
 }
+
+class _WindowsProcessProfiler extends ProcessProfiler {
+  _WindowsProcessProfiler() : super._();
+
+  @override
+  Future<UsageInfo?> getProcessUsage(int processId) async {
+    try {
+      var result = await Process.run(
+          'tasklist', ['/FI', 'PID eq $processId', '/NH', '/FO', 'csv']);
+
+      if (result.exitCode != 0) {
+        return Future.value(null);
+      }
+
+      return Future.value(_parse(result.stdout as String));
+    } catch (e) {
+      return Future.error(e);
+    }
+  }
+
+  UsageInfo? _parse(String tasklistResults) {
+    try {
+      var lines = tasklistResults.split(RegExp("\r?\n"));
+      for (var line in lines) {
+        if (line.trim().isEmpty) continue;
+        // Hacky parsing of csv line.
+        var entries = jsonDecode("[$line]") as List;
+        if (entries.length != 5) continue;
+        // E.g. 123,456 K
+        var memory = entries[4] as String;
+        memory = memory.substring(0, memory.indexOf(" "));
+        memory = memory.replaceAll(",", "");
+        memory = memory.replaceAll(".", "");
+        return UsageInfo(null, int.parse(memory));
+      }
+      return null;
+    } catch (e) {
+      return null;
+    }
+  }
+}

pkg/analysis_server/test/src/utilities/profiling_test.dart

@@ -3,17 +3,13 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:io';
+import 'dart:typed_data';
 
 import 'package:analysis_server/src/utilities/profiling.dart';
 import 'package:test/test.dart';
 
 void main() {
   group('ProcessProfiler', () {
-    // Skip on windows.
-    if (Platform.isWindows) {
-      return;
-    }
-
     test('getProfilerForPlatform', () async {
       expect(ProcessProfiler.getProfilerForPlatform(), isNotNull);
     });
@@ -22,8 +18,28 @@ void main() {
       var profiler = ProcessProfiler.getProfilerForPlatform()!;
       var info = (await profiler.getProcessUsage(pid))!;
 
-      expect(info.cpuPercentage, greaterThanOrEqualTo(0.0));
+      print("Uses ${info.memoryKB} KB");
+
+      if (Platform.isWindows) {
+        expect(info.cpuPercentage, isNull);
+      } else {
+        expect(info.cpuPercentage, greaterThanOrEqualTo(0.0));
+      }
       expect(info.memoryKB, greaterThanOrEqualTo(0));
+
+      // Use ~50 MB more memory and ensure that we actually use more memory
+      // as reported by the return value.
+      Uint8List use50mb = Uint8List(50 * 1024 * 1024);
+      for (int i = 0; i < use50mb.length; i++) {
+        use50mb[i] = i % 200;
+      }
+      var info2 = (await profiler.getProcessUsage(pid))!;
+      print("Now uses ${info2.memoryKB} KB");
+
+      for (var b in use50mb) {
+        if (b < 0) throw "This shouldn't happen, but we're using the data!";
+      }
+      expect(info2.memoryKB, greaterThan(info.memoryKB));
     });
   });
 }