Experimental `getDiagnostics` request (#24480).

pkg/analysis_server/lib/src/domain_experimental.dart

 // 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.
 
 library src.domain_experimental;
 
+import 'dart:collection';
 import 'dart:core' hide Resource;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/analysis_server.dart';
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/src/context/cache.dart';
+import 'package:analyzer/src/context/context.dart';
+import 'package:analyzer/src/generated/engine.dart'
+    hide AnalysisCache, AnalysisContextImpl;
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/generated/utilities_collection.dart';
+import 'package:analyzer/src/task/driver.dart';
+import 'package:analyzer/task/model.dart';
 
-/**
- * Instances of the class [ExperimentalDomainHandler] implement a
- * [RequestHandler] that handles requests in the `experimental` domain.
- */
+/// Extract context data from the given [context].
+ContextData extractData(AnalysisContext context) {
+  int explicitFiles = 0;
+  int implicitFiles = 0;
+  int workItems = 0;
+  Set<String> exceptions = new HashSet<String>();
+  if (context is AnalysisContextImpl) {
+    // Work Item count.
+    AnalysisDriver driver = context.driver;
+    List<WorkItem> items = driver.currentWorkOrder?.workItems;
+    workItems ??= items?.length;
+    var cache = context.analysisCache;
+    if (cache is AnalysisCache) {
+      Set<AnalysisTarget> countedTargets = new HashSet<AnalysisTarget>();
+      MapIterator<AnalysisTarget, CacheEntry> iterator = cache.iterator();
+      while (iterator.moveNext()) {
+        AnalysisTarget target = iterator.key;
+        if (countedTargets.add(target)) {
+          CacheEntry cacheEntry = iterator.value;
+          if (target is Source) {
+            if (cacheEntry.explicitlyAdded) {
+              explicitFiles++;
+            } else {
+              implicitFiles++;
+            }
+          }
+          // Caught exceptions.
+          if (cacheEntry.exception != null) {
+            exceptions.add(cacheEntry.exception.toString());
+          }
+        }
+      }
+    }
+  }
+  return new ContextData(context.name, explicitFiles, implicitFiles, workItems,
+      exceptions.toList());
+}
+
+/// Instances of the class [ExperimentalDomainHandler] implement a
+/// [RequestHandler] that handles requests in the `experimental` domain.
 class ExperimentalDomainHandler implements RequestHandler {
-  /**
-   * The analysis server that is using this handler to process requests.
-   */
+  /// The name of the request used to get diagnostic information.
+  static const String EXPERIMENTAL_DIAGNOSTICS = 'experimental.getDiagnostics';
+
+  /// The analysis server that is using this handler to process requests.
   final AnalysisServer server;
 
-  /**
-   * The name of the request used to get diagnostic information.
-   */
-  static const String EXPERIMENTAL_DIAGNOSTICS = 'experimental.diagnostics';
+  /// Initialize a newly created handler to handle requests for the given
+  /// [server].
+  ExperimentalDomainHandler(this.server);
 
-  /**
-   * Initialize a newly created handler to handle requests for the given [server].
-   */
-  ExperimentalDomainHandler(this.server);
+  /// Answer the `experimental.diagnostics` request.
+  Response computeDiagnostics(Request request) {
+    List<ContextData> infos = <ContextData>[];
+    server.folderMap.forEach((Folder folder, AnalysisContext context) {
+      infos.add(extractData(context));
+    });
+
+    return new ExperimentalGetDiagnosticsResult(infos).toResponse(request.id);
+  }
 
   @override
   Response handleRequest(Request request) {
     try {
       String requestName = request.method;
       if (requestName == EXPERIMENTAL_DIAGNOSTICS) {
         return computeDiagnostics(request);
       }
     } on RequestFailure catch (exception) {
       return exception.response;
     }
     return null;
   }
-
-  /**
-   * Implement the `experimental.diagnostics` request.
-   */
-  Response computeDiagnostics(Request request) {
-    return new Response.unknownRequest(request);
-  }
 }