Delegating AST Visitor and Linter refactoring.

pkg/analyzer/lib/src/generated/resolver.dart

Index: pkg/analyzer/lib/src/generated/resolver.dart
===================================================================
--- pkg/analyzer/lib/src/generated/resolver.dart	(revision 42896)
+++ pkg/analyzer/lib/src/generated/resolver.dart	(working copy)
@@ -8,6 +8,7 @@
 import 'dart:collection';
 
 import 'package:analyzer/src/generated/utilities_collection.dart';
+import 'package:analyzer/src/generated/visitors.dart';
 
 import 'ast.dart';
 import 'constant.dart';
@@ -4470,54 +4471,6 @@
 }
 
 
-/// 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 verifiers.
-  static final List<LintVerifier> VERIFIERS = <LintVerifier>[];
-
-  final Iterable<CompilationUnit> _compilationUnits;
-  final AnalysisErrorListener _errorListener;
-  final Iterable<LintVerifier> _verifiers;
-
-  LintGenerator(this._compilationUnits, this._errorListener,
-      [Iterable<LintVerifier> verifiers])
-      : _verifiers = verifiers != null ? verifiers : VERIFIERS;
-
-  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);
-    _verifiers.forEach((verifier) {
-      verifier.reporter = errorReporter;
-      return unit.accept(verifier);
-    });
-  }
-}
-
-/// Implementers contribute lint warnings via the provided error [reporter].
-abstract class LintVerifier extends RecursiveAstVisitor<Object> {
-  /// Used to report lint warnings.
-  /// NOTE: this is set by the framework before visit begins.
-  ErrorReporter reporter;
-}
-
-
 /**
  * Instances of the class {@code HtmlTagInfo} record information about the tags used in an HTML
  * file.
@@ -9249,6 +9202,57 @@
   }
 }
 
+/// 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)));
+  }
+}
+
 /**
  * This class is used to replace uses of `HashMap<String, ExecutableElement>` which are not as
  * performant as this class.