Initial Kythe support for plugins

pkg/analyzer_plugin/lib/plugin/kythe_mixin.dart

Index: pkg/analyzer_plugin/lib/plugin/kythe_mixin.dart
diff --git a/pkg/analyzer_plugin/lib/plugin/kythe_mixin.dart b/pkg/analyzer_plugin/lib/plugin/kythe_mixin.dart
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+// 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 'dart:async';
+
+import 'package:analyzer/dart/analysis/results.dart';
+import 'package:analyzer/src/dart/analysis/driver.dart';
+import 'package:analyzer_plugin/plugin/plugin.dart';
+import 'package:analyzer_plugin/protocol/protocol.dart';
+import 'package:analyzer_plugin/protocol/protocol_generated.dart';
+import 'package:analyzer_plugin/src/utilities/kythe/entries.dart';
+import 'package:analyzer_plugin/utilities/generator.dart';
+import 'package:analyzer_plugin/utilities/kythe/entries.dart';
+
+/**
+ * A mixin that can be used when creating a subclass of [ServerPlugin] and
+ * mixing in [KytheMixin]. This implements the creation of the kythe.getEntries
+ * request based on the assumption that the driver being created is an
+ * [AnalysisDriver].
+ *
+ * Clients may not extend or implement this class, but are allowed to use it as
+ * a mix-in when creating a subclass of [ServerPlugin] that also uses
+ * [KytheMixin] as a mix-in.
+ */
+abstract class DartEntryMixin implements EntryMixin {
+  @override
+  Future<EntryRequest> getEntryRequest(
+      KytheGetKytheEntriesParams parameters) async {
+    String path = parameters.file;
+    AnalysisDriver driver = driverForPath(path);
+    if (driver == null) {
+      // Return an error from the request.
+      throw new RequestFailure(
+          RequestErrorFactory.pluginError('Failed to analyze $path', null));
+    }
+    ResolveResult result = await driver.getResult(path);
+    return new DartEntryRequestImpl(resourceProvider, result);
+  }
+}
+
+/**
+ * A mixin that can be used when creating a subclass of [ServerPlugin] to
+ * provide most of the implementation for handling kythe.getEntries requests.
+ *
+ * Clients may not extend or implement this class, but are allowed to use it as
+ * a mix-in when creating a subclass of [ServerPlugin].
+ */
+abstract class EntryMixin implements ServerPlugin {
+  /**
+   * Return a list containing the entry contributors that should be used to
+   * create entries for the file with the given [path]
+   */
+  List<EntryContributor> getEntryContributors(String path);
+
+  /**
+   * Return the entries request that should be passes to the contributors
+   * returned from [getEntryContributors].
+   */
+  Future<EntryRequest> getEntryRequest(KytheGetKytheEntriesParams parameters);
+
+  @override
+  Future<KytheGetKytheEntriesResult> handleKytheGetKytheEntries(
+      KytheGetKytheEntriesParams parameters) async {
+    String path = parameters.file;
+    EntryRequest request = await getEntryRequest(parameters);
+    EntryGenerator generator = new EntryGenerator(getEntryContributors(path));
+    GeneratorResult result =
+        await generator.generateGetEntriesResponse(request);
+    result.sendNotifications(channel);
+    return result.result;
+  }
+}