Forward Kythe requests to plugins and merge in the results

pkg/analysis_server/lib/src/domain_kythe.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 'dart:async';
 import 'dart:core';
 
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
+import 'package:analysis_server/src/domain_abstract.dart';
+import 'package:analysis_server/src/plugin/plugin_manager.dart';
+import 'package:analysis_server/src/plugin/result_merger.dart';
 import 'package:analysis_server/src/services/kythe/kythe_visitors.dart';
+import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/dart/resolver/inheritance_manager.dart';
+import 'package:analyzer_plugin/protocol/protocol.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
+import 'package:analyzer_plugin/protocol/protocol_constants.dart' as plugin;
+import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 
 /**
  * Instances of the class [KytheDomainHandler] implement a [RequestHandler]
  * that handles requests in the `kythe` domain.
  */
-class KytheDomainHandler implements RequestHandler {
-  /**
-   * The analysis server that is using this handler to process requests.
-   */
-  final AnalysisServer server;
-
+class KytheDomainHandler extends AbstractRequestHandler {
   /**
    * Initialize a newly created handler to handle requests for the given [server].
    */
-  KytheDomainHandler(this.server);
+  KytheDomainHandler(AnalysisServer server) : super(server);
 
   /**
    * Implement the `kythe.getKytheEntries` request.
    */
   Future<Null> getKytheEntries(Request request) async {
     String file = new KytheGetKytheEntriesParams.fromRequest(request).file;
-    AnalysisResult result = await server.getAnalysisResult(file);
-    List<KytheEntry> entries = <KytheEntry>[];
-    // TODO(brianwilkerson) Figure out how to get the list of files.
-    List<String> files = <String>[];
-    result.unit.accept(new KytheDartVisitor([] /*entries*/, file,
-        new InheritanceManager(result.libraryElement), result.content));
-    server.sendResponse(
-        new KytheGetKytheEntriesResult(entries, files).toResponse(request.id));
+    AnalysisDriver driver = server.getAnalysisDriver(file);
+    if (driver == null) {
+      server.sendResponse(new Response.getKytheEntriesInvalidFile(request));
+    } else {
+      //
+      // Allow plugins to start computing entries.
+      //
+      plugin.KytheGetKytheEntriesParams requestParams =
+          new plugin.KytheGetKytheEntriesParams(file);
+      Map<PluginInfo, Future<plugin.Response>> pluginFutures = server
+          .pluginManager
+          .broadcastRequest(requestParams, contextRoot: driver.contextRoot);
+      //
+      // Compute entries generated by server.
+      //
+      List<KytheGetKytheEntriesResult> allResults =
+          <KytheGetKytheEntriesResult>[];
+      AnalysisResult result = await server.getAnalysisResult(file);
+      CompilationUnit unit = result?.unit;
+      if (unit != null && result.exists) {
+        List<KytheEntry> entries = <KytheEntry>[];
+        // TODO(brianwilkerson) Figure out how to get the list of files.
+        List<String> files = <String>[];
+        result.unit.accept(new KytheDartVisitor(entries, file,
+            new InheritanceManager(result.libraryElement), result.content));
+        allResults.add(new KytheGetKytheEntriesResult(entries, files));
+      }
+      //
+      // Add the entries produced by plugins to the server-generated entries.
+      //
+      if (pluginFutures != null) {
+        List<plugin.Response> responses = await waitForResponses(pluginFutures,
+            requestParameters: requestParams);
+        for (plugin.Response response in responses) {
+          plugin.KytheGetKytheEntriesResult result =
+              new plugin.KytheGetKytheEntriesResult.fromResponse(response);
+          allResults.add(
+              new KytheGetKytheEntriesResult(result.entries, result.files));
+        }
+      }
+      //
+      // Return the result.
+      //
+      ResultMerger merger = new ResultMerger();
+      KytheGetKytheEntriesResult mergedResults =
+          merger.mergeKytheEntries(allResults);
+      if (mergedResults == null) {
+        server.sendResponse(
+            new KytheGetKytheEntriesResult(<KytheEntry>[], <String>[])
+                .toResponse(request.id));
+      } else {
+        server.sendResponse(new KytheGetKytheEntriesResult(
+                mergedResults.entries, mergedResults.files)
+            .toResponse(request.id));
+      }
+    }
   }
 
   @override
   Response handleRequest(Request request) {
     try {
       String requestName = request.method;
       if (requestName == KYTHE_REQUEST_GET_KYTHE_ENTRIES) {
         getKytheEntries(request);
         return Response.DELAYED_RESPONSE;
       }
     } on RequestFailure catch (exception) {
       return exception.response;
     }
     return null;
   }
 }