[dartdev] push the analysisFinished logic down into the AnalysisServer wrapper

Change-Id: Idf2c7422046365bae056c8c767ed915ad91d7cf2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/166560
Reviewed-by: Phil Quitslund <pquitslund@google.com>
Commit-Queue: Devon Carew <devoncarew@google.com>

Author: devoncarew

pkg/dartdev/lib/src/commands/analyze.dart

@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
-import 'dart:io';
+import 'dart:io' as io;
 
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as path;
@@ -43,45 +43,41 @@ class AnalyzeCommand extends DartdevCommand<int> {
 
     // find directory from argResults.rest
     var dir = argResults.rest.isEmpty
-        ? Directory.current
-        : Directory(argResults.rest.single);
+        ? io.Directory.current
+        : io.Directory(argResults.rest.single);
     if (!dir.existsSync()) {
       usageException("Directory doesn't exist: ${dir.path}");
     }
 
-    final Completer<void> analysisCompleter = Completer<void>();
     final List<AnalysisError> errors = <AnalysisError>[];
 
     var progress = log.progress('Analyzing ${path.basename(dir.path)}');
 
     final AnalysisServer server = AnalysisServer(
-      Directory(sdk.sdkPath),
+      io.Directory(sdk.sdkPath),
       [dir],
     );
 
-    StreamSubscription<bool> subscription;
-    subscription = server.onAnalyzing.listen((bool isAnalyzing) {
-      if (!isAnalyzing) {
-        analysisCompleter.complete();
-        subscription.cancel();
-      }
-    });
     server.onErrors.listen((FileAnalysisErrors fileErrors) {
       // Record the issues found (but filter out to do comments).
       errors.addAll(fileErrors.errors
           .where((AnalysisError error) => error.type != 'TODO'));
     });
 
     await server.start();
-    // Completing the future in the callback can't fail.
-    //ignore: unawaited_futures
+
+    bool analysisFinished = false;
+
+    // ignore: unawaited_futures
     server.onExit.then((int exitCode) {
-      if (!analysisCompleter.isCompleted) {
-        analysisCompleter.completeError('analysis server exited: $exitCode');
+      if (!analysisFinished) {
+        io.exitCode = exitCode;
       }
     });
 
-    await analysisCompleter.future;
+    await server.analysisFinished;
+    analysisFinished = true;
+
     // todo (pq): consider server.shutdown() for cleaner dispose.
     await server.dispose();
     progress.finish(showTiming: true);

pkg/dartdev/lib/src/commands/analyze_impl.dart

@@ -24,6 +24,7 @@ class AnalysisServer {
   Process _process;
   final StreamController<bool> _analyzingController =
       StreamController<bool>.broadcast();
+  Completer<bool> _analysisFinished = Completer();
   final StreamController<EditBulkFixesResult> _bulkFixesController =
       StreamController<EditBulkFixesResult>.broadcast();
   final StreamController<FileAnalysisErrors> _errorsController =
@@ -41,6 +42,11 @@ class AnalysisServer {
 
   Stream<bool> get onAnalyzing => _analyzingController.stream;
 
+  /// This future completes when we next receive an analysis finished event
+  /// (unless there's not current analysis and we've already received a complete
+  /// event, in which case this future immediately completes).
+  Future<bool> get analysisFinished => _analysisFinished.future;
+
   Stream<FileAnalysisErrors> get onErrors => _errorsController.stream;
 
   Stream<EditBulkFixesResult> get onBulkFixes => _bulkFixesController.stream;
@@ -58,7 +64,7 @@ class AnalysisServer {
 
     _process = await startDartProcess(sdk, command);
     // This callback hookup can't throw.
-    //ignore: unawaited_futures
+    // ignore: unawaited_futures
     _process.exitCode.whenComplete(() => _process = null);
 
     final Stream<String> errorStream = _process.stderr
@@ -86,6 +92,16 @@ class AnalysisServer {
       path.context.separator,
     );
 
+    onAnalyzing.listen((bool isAnalyzing) {
+      if (isAnalyzing && _analysisFinished.isCompleted) {
+        // Start a new completer, to be completed when we receive the
+        // corresponding analysis complete event.
+        _analysisFinished = Completer();
+      } else if (!isAnalyzing && !_analysisFinished.isCompleted) {
+        _analysisFinished.complete(true);
+      }
+    });
+
     _sendCommand('analysis.setAnalysisRoots', <String, dynamic>{
       'included': [dirPath],
       'excluded': <String>[]