Reapply "Move the linter core to the analyzer package"

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

Index: pkg/analyzer/lib/src/lint/project.dart
diff --git a/pkg/analyzer/lib/src/lint/project.dart b/pkg/analyzer/lib/src/lint/project.dart
new file mode 100644
index 0000000000000000000000000000000000000000..9b22294e15c0a400b850869021a265ce31685fb6
--- /dev/null
+++ b/pkg/analyzer/lib/src/lint/project.dart
@@ -0,0 +1,129 @@
+// 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.
+
+import 'dart:io';
+
+import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/resolver.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/lint/io.dart';
+import 'package:analyzer/src/lint/pub.dart';
+import 'package:path/path.dart' as p;
+
+Pubspec _findAndParsePubspec(Directory root) {
+  if (root.existsSync()) {
+    File pubspec = root
+        .listSync(followLinks: false)
+        .firstWhere((f) => isPubspecFile(f), orElse: () => null);
+    if (pubspec != null) {
+      return new Pubspec.parse(pubspec.readAsStringSync(),
+          sourceUrl: p.toUri(pubspec.path));
+    }
+  }
+  return null;
+}
+
+/// A semantic representation of a Dart project.
+///
+/// Projects provide a semantic model of a Dart project based on the
+/// [pub package layout conventions](https://www.dartlang.org/tools/pub/package-layout.html).
+/// This model allows clients to traverse project contents in a convenient and
+/// standardized way, access global information (such as whether elements are
+/// in the "public API") and resources that have special meanings in the
+/// context of pub package layout conventions.
+class DartProject {
+  _ApiModel _apiModel;
+  String _name;
+  Pubspec _pubspec;
+
+  /// Project root.
+  final Directory root;
+
+  /// Create a Dart project for the corresponding [context] and [sources].
+  /// If a [dir] is unspecified the current working directory will be
+  /// used.
+  DartProject(AnalysisContext context, List<Source> sources, {Directory dir})
+      : root = dir ?? Directory.current {
+    _pubspec = _findAndParsePubspec(root);
+    _apiModel = new _ApiModel(context, sources, root);
+  }
+
+  /// The project's name.
+  ///
+  /// Project names correspond to the package name as specified in the project's
+  /// [pubspec]. The pubspec is found relative to the project [root].  If no
+  /// pubspec can be found, the name defaults to the project root basename.
+  String get name => _name ??= _calculateName();
+
+  /// The project's pubspec.
+  Pubspec get pubspec => _pubspec;
+
+  /// Returns `true` if the given element is part of this project's public API.
+  ///
+  /// Public API elements are defined as all elements that are in the packages's
+  /// `lib` directory, *less* those in `lib/src` (which are treated as private
+  /// *implementation files*), plus elements having been explicitly exported
+  /// via an `export` directive.
+  bool isApi(Element element) => _apiModel.contains(element);
+
+  String _calculateName() {
+    if (pubspec != null) {
+      var nameEntry = pubspec.name;
+      if (nameEntry != null) {
+        return nameEntry.value.text;
+      }
+    }
+    return p.basename(root.path);
+  }
+}
+
+/// An object that can be used to visit Dart project structure.
+abstract class ProjectVisitor<T> {
+  T visit(DartProject project) => null;
+}
+
+/// Captures the project's API as defined by pub package layout standards.
+class _ApiModel {
+  final AnalysisContext context;
+  final List<Source> sources;
+  final Directory root;
+  final Set<LibraryElement> elements = new Set();
+
+  _ApiModel(this.context, this.sources, this.root) {
+    _calculate();
+  }
+
+  /// Return `true` if this element is part of the public API for this package.
+  bool contains(Element element) {
+    while (element != null) {
+      if (!element.isPrivate && elements.contains(element)) {
+        return true;
+      }
+      element = element.enclosingElement;
+    }
+    return false;
+  }
+
+  _calculate() {
+    if (sources == null || sources.isEmpty) {
+      return;
+    }
+
+    var libDir = root.path + '/lib';
+    var libSrcDir = libDir + '/src';
+
+    for (Source source in sources) {
+      var path = source.uri.path;
+      if (path.startsWith(libDir) && !path.startsWith(libSrcDir)) {
+        var library = context.computeLibraryElement(source);
+        var namespaceBuilder = new NamespaceBuilder();
+        var exports = namespaceBuilder.createExportNamespaceForLibrary(library);
+        var public = namespaceBuilder.createPublicNamespaceForLibrary(library);
+        elements.addAll(exports.definedNames.values);
+        elements.addAll(public.definedNames.values);
+      }
+    }
+  }
+}