Statement completion framework with a few examples

pkg/analysis_server/lib/src/edit/edit_domain.dart

 // Copyright (c) 2014, 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 edit.domain;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
 import 'package:analysis_server/plugin/edit/assist/assist_dart.dart';
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/plugin/edit/fix/fix_dart.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/collections.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
+import 'package:analysis_server/src/services/completion/statement/statement_completion.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/assist_internal.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/fix_internal.dart';
 import 'package:analysis_server/src/services/correction/organize_directives.dart';
 import 'package:analysis_server/src/services/correction/sort_members.dart';
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 215 matching lines @@
           }
         }
       }
     }
 
     // Send the response.
     server.sendResponse(
         new EditGetFixesResult(errorFixesList).toResponse(request.id));
   }
 
+  Future getStatementCompletion(Request request) async {
+    var params = new EditGetStatementCompletionParams.fromRequest(request);
+    SourceChange change;
+
+    server.contextManager.getContextFor(params.file);
+    server.contextManager.getDriverFor(params.file);

[Brian Wilkerson, 2017/04/07 19:17:14]

Are the two lines above necessary because of a side-effect? (If so, we should
document that, otherwise someone is likely to try to remove them.

[scheglov, 2017/04/07 19:36:07]

I don't think these two statements are useful.

[messick, 2017/04/07 20:10:09]

Done.

+    AnalysisResult result = await server.getAnalysisResult(params.file);
+    if (result != null) {
+      CompilationUnit unit = result.unit;
+      CompilationUnitElement unitElement =
+          resolutionMap.elementDeclaredByCompilationUnit(unit);
+      if (unitElement.context != null) {
+        StatementCompletionContext context = new StatementCompletionContext(
+            unitElement,
+            params.offset,
+            result.lineInfo,
+            result.errors,
+            params.file,
+            unit);
+        StatementCompletionProcessor processor =
+            new StatementCompletionProcessor(context);
+        StatementCompletion completion = await processor.compute();
+        change = completion.change;
+      }
+    }
+    if (change == null) {
+      change = new SourceChange("", edits: []);

[Brian Wilkerson, 2017/04/07 19:17:14]

Consider using "??=".

+    }
+
+    Response response = new EditGetStatementCompletionResult(change, false)
+        .toResponse(request.id);
+    server.sendResponse(response);
+  }
+
   @override
   Response handleRequest(Request request) {
     try {
       String requestName = request.method;
       if (requestName == EDIT_FORMAT) {
         return format(request);
       } else if (requestName == EDIT_GET_ASSISTS) {
         getAssists(request);
         return Response.DELAYED_RESPONSE;
       } else if (requestName == EDIT_GET_AVAILABLE_REFACTORINGS) {
         return _getAvailableRefactorings(request);
       } else if (requestName == EDIT_GET_FIXES) {
         getFixes(request);
         return Response.DELAYED_RESPONSE;
       } else if (requestName == EDIT_GET_REFACTORING) {
         return _getRefactoring(request);
       } else if (requestName == EDIT_ORGANIZE_DIRECTIVES) {
         organizeDirectives(request);
         return Response.DELAYED_RESPONSE;
       } else if (requestName == EDIT_SORT_MEMBERS) {
         sortMembers(request);
         return Response.DELAYED_RESPONSE;
+      } else if (requestName == EDIT_GET_STATEMENT_COMPLETION) {
+        getStatementCompletion(request);
+        return Response.DELAYED_RESPONSE;
       }
     } on RequestFailure catch (exception) {
       return exception.response;
     }
     return null;
   }
 
   Future<Null> organizeDirectives(Request request) async {
     var params = new EditOrganizeDirectivesParams.fromRequest(request);
     // prepare file
@@ skipping 687 matching lines @@
     }
     return new RefactoringStatus();
   }
 }
 
 /**
  * [_RefactoringManager] throws instances of this class internally to stop
  * processing in a manager that was reset.
  */
 class _ResetError {}