Implement 'edit.getRefactoring' for rename refactoring.

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/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/edit/fix.dart';
 import 'package:analysis_server/src/protocol.dart';
+import 'package:analysis_server/src/protocol2.dart' as protocol show
+    LinkedEditGroup;
 import 'package:analysis_server/src/protocol2.dart' show AnalysisError,
     EditGetAssistsParams, EditGetAvailableRefactoringsParams,
-    EditGetAvailableRefactoringsResult, EditGetFixesParams, RefactoringKind;
+    EditGetAvailableRefactoringsResult, EditGetFixesParams,
+    EditGetRefactoringParams, EditGetRefactoringResult, LinkedEditGroup, Location,
+    RefactoringKind, RefactoringProblem, RefactoringProblemSeverity, RenameOptions,
+    SourceChange;
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/change.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
+import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/json.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/engine.dart' as engine;
 import 'package:analyzer/src/generated/error.dart' as engine;
 import 'package:analyzer/src/generated/source.dart';
 
 
 /**
  * Instances of the class [EditDomainHandler] implement a [RequestHandler]
  * that handles requests in the edit domain.
  */
 class EditDomainHandler implements RequestHandler {
   /**
    * The analysis server that is using this handler to process requests.
    */
   final AnalysisServer server;
 
   /**
    * The [SearchEngine] for this server.
    */
   SearchEngine searchEngine;
 
+  _RefactoringManager refactoringManager;
+
   /**
    * Initialize a newly created handler to handle requests for the given [server].
    */
   EditDomainHandler(this.server) {
     searchEngine = server.searchEngine;
+    refactoringManager = new _RefactoringManager(server, searchEngine);
   }
 
   Response getAssists(Request request) {
     var params = new EditGetAssistsParams.fromRequest(request);
     List<Change> changes = <Change>[];
     List<CompilationUnit> units =
         server.getResolvedCompilationUnits(params.file);
     if (units.isNotEmpty) {
       CompilationUnit unit = units[0];
       List<Assist> assists =
@@ skipping 66 matching lines @@
       }
     }
     // respond
     return new Response(request.id)..setResult(FIXES, errorFixesList);
   }
 
   @override
   Response handleRequest(Request request) {
     try {
       String requestName = request.method;
-      if (requestName == EDIT_GET_AVAILABLE_REFACTORINGS) {
+      if (requestName == EDIT_GET_ASSISTS) {
+        return getAssists(request);
+      } else if (requestName == EDIT_GET_AVAILABLE_REFACTORINGS) {
         return getAvailableRefactorings(request);
-      } else if (requestName == EDIT_GET_ASSISTS) {
-        return getAssists(request);
       } else if (requestName == EDIT_GET_FIXES) {
         return getFixes(request);
+      } else if (requestName == EDIT_GET_REFACTORING) {
+        refactoringManager.getRefactoring(request);
+        return Response.DELAYED_RESPONSE;
       }
     } on RequestFailure catch (exception) {
       return exception.response;
     }
     return null;
   }
 }
+
+
+/**
+ * An object managing a single [Refactoring] instance.
+ *
+ * The instance is identified by its kind, file, offset and length.
+ * It is initialized when the a set of parameters is given for the first time.
+ * All subsequent requests are performed on this [Refactoring] instance.
+ *
+ * Once new set of parameters is received, the previous [Refactoring] instance
+ * is invalidated and a new one is created and initialized.
+ */
+class _RefactoringManager {
+  final AnalysisServer server;
+  final SearchEngine searchEngine;
+
+  RefactoringKind kind;
+  String file;
+  int offset;
+  int length;
+  Refactoring refactoring;
+  RefactoringStatus initStatus;
+  RefactoringStatus optionsStatus;
+  RefactoringStatus finalStatus;
+
+  String requestId;
+  EditGetRefactoringResult result;
+
+  _RefactoringManager(this.server, this.searchEngine) {
+    _reset();
+  }
+
+  bool get _hasFatalError {
+    return initStatus.hasFatalError ||
+        optionsStatus.hasFatalError ||
+        finalStatus.hasFatalError;
+  }
+
+  void getRefactoring(Request request) {
+    // prepare for processing the request
+    requestId = request.id;
+    result = new EditGetRefactoringResult(<RefactoringProblem>[]);
+    // process the request
+    var params = new EditGetRefactoringParams.fromRequest(request);
+    _init(params.kind, params.file, params.offset, params.length).then((_) {
+      if (_hasFatalError) {
+        return _sendResultResponse();
+      }
+      // set options
+      if (params.options == null) {
+        return _sendResultResponse();
+      }
+      optionsStatus = _setOptions(params.options);
+      if (_hasFatalError) {
+        return _sendResultResponse();
+      }
+      // done if just validation
+      if (params.validateOnly) {
+        return _sendResultResponse();
+      }
+      // validation and create change
+      refactoring.checkFinalConditions().then((_finalStatus) {
+        finalStatus = _finalStatus;
+        if (_hasFatalError) {
+          return _sendResultResponse();
+        }
+        return refactoring.createChange().then((change) {
+          result.change = new SourceChange(
+              change.message,
+              change.fileEdits,
+              <protocol.LinkedEditGroup>[]);
+          return _sendResultResponse();
+        });
+      });
+    });
+  }
+
+  /**
+   * Initializes this context to perform a refactoring with the specified
+   * parameters. The existing [Refactoring] is reused or created as needed.
+   */
+  Future<RefactoringStatus> _init(RefactoringKind kind, String file, int offset,
+      int length) {
+    List<RefactoringProblem> problems = <RefactoringProblem>[];
+    // check if we can continue with the existing Refactoring instance
+    if (this.kind == kind &&
+        this.file == file &&
+        this.offset == offset &&
+        this.length == length) {
+      return new Future.value(initStatus);
+    }
+    _reset();
+    this.kind = kind;
+    this.file = file;
+    this.offset = offset;
+    this.length = length;
+    // create a new Refactoring instance
+    if (kind == RefactoringKind.RENAME) {
+      List<Element> elements = server.getElementsAtOffset(file, offset);
+      if (elements.isNotEmpty) {
+        Element element = elements[0];
+        refactoring = new RenameRefactoring(searchEngine, element);
+      }
+    }
+    if (refactoring == null) {
+      initStatus =
+          new RefactoringStatus.fatal('Unable to create a refactoring');
+      return new Future.value(initStatus);
+    }
+    // check initial conditions
+    return refactoring.checkInitialConditions().then((status) {
+      initStatus = status;
+      return initStatus;
+    });
+  }
+
+  void _reset() {
+    refactoring = null;
+    initStatus = new RefactoringStatus();
+    optionsStatus = new RefactoringStatus();
+    finalStatus = new RefactoringStatus();
+  }
+
+  void _sendResultResponse() {
+    // set problems
+    {
+      RefactoringStatus status = new RefactoringStatus();
+      status.addStatus(initStatus);
+      status.addStatus(optionsStatus);
+      status.addStatus(finalStatus);
+      result.problems = status.problems;
+    }
+    // send the response
+    server.sendResponse(result.toResponse(requestId));
+    // done with this request
+    requestId = null;
+    result = null;
+  }
+
+  RefactoringStatus _setOptions(Object options) {
+    if (refactoring is RenameRefactoring) {
+      RenameRefactoring renameRefactoring = refactoring;
+      RenameOptions renameOptions = options;
+      String newName = renameOptions.newName;
+      renameRefactoring.newName = newName;
+      return renameRefactoring.checkNewName();
+    }
+    return new RefactoringStatus();
+  }
+}