Initial Kythe support for plugins

pkg/analyzer_plugin/lib/utilities/kythe/entries.dart

+// Copyright (c) 2017, 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 'package:analyzer/dart/analysis/results.dart';
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer_plugin/protocol/protocol.dart';
+import 'package:analyzer_plugin/protocol/protocol_common.dart' show KytheEntry;
+import 'package:analyzer_plugin/protocol/protocol_generated.dart';
+import 'package:analyzer_plugin/src/utilities/kythe/entries.dart';
+import 'package:analyzer_plugin/utilities/generator.dart';
+
+/**
+ * The information about a requested set of entries when computing entries in a
+ * `.dart` file.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class DartEntryRequest implements EntryRequest {
+  /**
+   * The analysis result for the file in which the entries are being requested.
+   */
+  ResolveResult get result;
+}
+
+/**
+ * An object that [EntryContributor]s use to record entries.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class EntryCollector {
+  /**
+   * Record a new [entry].
+   */
+  void addEntry(KytheEntry entry);
+}
+
+/**
+ * An object used to produce entries.
+ *
+ * Clients may implement this class when implementing plugins.
+ */
+abstract class EntryContributor {
+  /**
+   * Contribute entries for the file specified by the given [request] into the
+   * given [collector].
+   */
+  void computeEntries(EntryRequest request, EntryCollector collector);
+}
+
+/**
+ * A generator that will generate a 'kythe.getEntries' response.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+class EntryGenerator {
+  /**
+   * The contributors to be used to generate the entries.
+   */
+  final List<EntryContributor> contributors;
+
+  /**
+   * Initialize a newly created entry generator to use the given [contributors].
+   */
+  EntryGenerator(this.contributors);
+
+  /**
+   * Create a 'kythe.getEntries' response for the file specified by the given
+   * [request]. If any of the contributors throws an exception, also create a
+   * non-fatal 'plugin.error' notification.
+   */
+  GeneratorResult generateGetEntriesResponse(EntryRequest request) {
+    List<Notification> notifications = <Notification>[];
+    EntryCollectorImpl collector = new EntryCollectorImpl();
+    for (EntryContributor contributor in contributors) {
+      try {
+        contributor.computeEntries(request, collector);
+      } catch (exception, stackTrace) {
+        notifications.add(new PluginErrorParams(
+                false, exception.toString(), stackTrace.toString())
+            .toNotification());
+      }
+    }
+    KytheGetKytheEntriesResult result =
+        new KytheGetKytheEntriesResult(collector.entries, collector.files);
+    return new GeneratorResult(result, notifications);
+  }
+}
+
+/**
+ * The information about a requested set of entries.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class EntryRequest {
+  /**
+   * Return the path of the file in which entries are being requested.
+   */
+  String get path;
+
+  /**
+   * Return the resource provider associated with this request.
+   */
+  ResourceProvider get resourceProvider;
+}