Refactoring analyzer_cli for code hygiene.

pkg/analyzer_cli/lib/src/batch_mode.dart

+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file

[Brian Wilkerson, 2017/04/24 20:26:47]

We generally keep the copyright date from the old file when moving code out into
a new file. Not sure whether it makes any difference, though.

+// 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:async';
+import 'dart:convert';
+import 'dart:io' show exitCode, stdin;
+
+import 'package:analyzer/error/error.dart';
+
+typedef Future<ErrorSeverity> BatchRunnerHandler(List<String> args);
+
+/// Provides a framework to read command line options from stdin and feed them
+/// to a callback.
+class BatchRunner {
+  final outSink;
+  final errorSink;
+
+  BatchRunner(this.outSink, this.errorSink);
+
+  /// Run the tool in 'batch' mode, receiving command lines through stdin and
+  /// returning pass/fail status through stdout. This feature is intended for
+  /// use in unit testing.
+  void runAsBatch(List<String> sharedArgs, BatchRunnerHandler handler) {
+    outSink.writeln('>>> BATCH START');
+    Stopwatch stopwatch = new Stopwatch();
+    stopwatch.start();
+    int testsFailed = 0;
+    int totalTests = 0;
+    ErrorSeverity batchResult = ErrorSeverity.NONE;
+    // Read line from stdin.
+    Stream cmdLine =
+        stdin.transform(UTF8.decoder).transform(new LineSplitter());
+    cmdLine.listen((String line) async {
+      // Maybe finish.
+      if (line.isEmpty) {
+        var time = stopwatch.elapsedMilliseconds;
+        outSink.writeln(
+            '>>> BATCH END (${totalTests - testsFailed}/$totalTests) ${time}ms');
+        exitCode = batchResult.ordinal;
+      }
+      // Prepare arguments.
+      var lineArgs = line.split(new RegExp('\\s+'));
+      var args = new List<String>();
+      args.addAll(sharedArgs);
+      args.addAll(lineArgs);
+      args.remove('-b');
+      args.remove('--batch');
+      // Analyze single set of arguments.
+      try {
+        totalTests++;
+        ErrorSeverity result = await handler(args);
+        bool resultPass = result != ErrorSeverity.ERROR;
+        if (!resultPass) {
+          testsFailed++;
+        }
+        batchResult = batchResult.max(result);
+        // Write stderr end token and flush.
+        errorSink.writeln('>>> EOF STDERR');
+        String resultPassString = resultPass ? 'PASS' : 'FAIL';
+        outSink.writeln(
+            '>>> TEST $resultPassString ${stopwatch.elapsedMilliseconds}ms');
+      } catch (e, stackTrace) {
+        errorSink.writeln(e);
+        errorSink.writeln(stackTrace);
+        errorSink.writeln('>>> EOF STDERR');
+        outSink.writeln('>>> TEST CRASH');
+      }
+    });
+  }
+}