Linter API updates.

pkg/analyzer/lib/src/services/lint.dart

+// Copyright (c) 2015, 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 lint;
+
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/utilities_general.dart';
+import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/error.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/generated/visitors.dart';
+
+
+/// Implementers contribute lint warnings via the provided error [reporter].
+abstract class Linter {
+  /// Used to report lint warnings.
+  /// NOTE: this is set by the framework before visit begins.
+  ErrorReporter reporter;
+
+  /// Return a visitor to be passed to compilation units to perform lint
+  /// analysis.
+  /// Lint errors are reported via this [Linter]'s error [reporter].
+  AstVisitor getVisitor();
+}
+
+/// Traverses a library's worth of dart code at a time to generate lint warnings
+/// over the set of sources.
+///
+/// See [LintCode].
+class LintGenerator {
+
+  /// A global container for contributed linters.
+  static final List<Linter> LINTERS = <Linter>[];
+
+  final Iterable<CompilationUnit> _compilationUnits;
+  final AnalysisErrorListener _errorListener;
+  final Iterable<Linter> _linters;
+
+  LintGenerator(this._compilationUnits, this._errorListener,
+      [Iterable<Linter> linters])
+      : _linters = linters != null ? linters : LINTERS;
+
+  void generate() {
+    TimeCounter_TimeCounterHandle timeCounter =
+        PerformanceStatistics.lint.start();
+    try {
+      _compilationUnits.forEach((cu) {
+        if (cu.element != null) {
+          _generate(cu, cu.element.source);
+        }
+      });
+    } finally {
+      timeCounter.stop();
+    }
+  }
+
+  void _generate(CompilationUnit unit, Source source) {
+    ErrorReporter errorReporter = new ErrorReporter(_errorListener, source);
+    _linters.forEach((l) => l.reporter = errorReporter);
+    Iterable<AstVisitor> visitors = _linters.map((l) => l.getVisitor());
+    unit.accept(new DelegatingAstVisitor(visitors.where((v) => v != null)));
+  }
+}