Remove timeStamp from the ChangeBuilder API

pkg/analysis_server/lib/src/services/correction/assist_internal.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.
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
 import 'package:analysis_server/plugin/edit/assist/assist_dart.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
@@ skipping 27 matching lines @@
  * The computer for Dart assists.
  */
 class AssistProcessor {
   /**
    * The analysis driver being used to perform analysis.
    */
   AnalysisDriver driver;
 
   Source source;
   String file;
-  int fileStamp;
 
   CompilationUnit unit;
   CompilationUnitElement unitElement;
 
   LibraryElement unitLibraryElement;
   String unitLibraryFile;
   String unitLibraryFolder;
 
   int selectionOffset;
   int selectionLength;
   int selectionEnd;
 
   final List<Assist> assists = <Assist>[];
 
   Position exitPosition = null;
 
   CorrectionUtils utils;
 
   AstNode node;
 
   TypeProvider _typeProvider;
 
   AssistProcessor(DartAssistContext dartContext) {
     driver = dartContext.analysisDriver;
     // source
     source = dartContext.source;
     file = dartContext.source.fullName;
-    fileStamp = _modificationStamp(file);
     // unit
     unit = dartContext.unit;
     unitElement = dartContext.unit.element;
     // library
     unitLibraryElement = resolutionMap
         .elementDeclaredByCompilationUnit(dartContext.unit)
         .library;
     unitLibraryFile = unitLibraryElement.source.fullName;
     unitLibraryFolder = dirname(unitLibraryFile);
     // selection
     selectionOffset = dartContext.selectionOffset;
     selectionLength = dartContext.selectionLength;
     selectionEnd = selectionOffset + selectionLength;
   }
 
   /**
    * Returns the EOL to use for this [CompilationUnit].
    */
   String get eol => utils.endOfLine;
 
   TypeProvider get typeProvider {
     if (_typeProvider == null) {
       _typeProvider = unitElement.context.typeProvider;
     }
     return _typeProvider;
   }
 
   Future<List<Assist>> compute() async {
-    // If the source was changed between the constructor and running
-    // this asynchronous method, it is not safe to use the unit.
-    if (_modificationStamp(file) != fileStamp) {
-      return const <Assist>[];
-    }
-
     try {
       utils = new CorrectionUtils(unit);
     } catch (e) {
       throw new CancelCorrectionException(exception: e);
     }
 
     node = new NodeLocator(selectionOffset, selectionEnd).searchWithin(unit);
     if (node == null) {
       return assists;
     }
@@ skipping 110 matching lines @@
     _configureTargetLocation(node);
     Set<Source> librariesToImport = new Set<Source>();
     String typeSource = utils.getTypeSource(type, librariesToImport);
     if (typeSource == null) {
       // The type source might be null if the type is private.
       _coverageMarker();
       return;
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       Token keyword = declaredIdentifier.keyword;
       if (keyword.keyword == Keyword.VAR) {
         builder.addSimpleReplacement(range.token(keyword), typeSource);
       } else {
         builder.addSimpleInsertion(
             declaredIdentifier.identifier.offset, '$typeSource ');
       }
       builder.importLibraries(librariesToImport);
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.ADD_TYPE_ANNOTATION);
@@ skipping 27 matching lines @@
     _configureTargetLocation(node);
     Set<Source> librariesToImport = new Set<Source>();
     String typeSource = utils.getTypeSource(type, librariesToImport);
     // type source might be null, if the type is private
     if (typeSource == null) {
       _coverageMarker();
       return;
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addSimpleInsertion(name.offset, '$typeSource ');
       builder.importLibraries(librariesToImport);
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.ADD_TYPE_ANNOTATION);
   }
 
   Future<Null> _addProposal_addTypeAnnotation_VariableDeclaration() async {
     AstNode node = this.node;
     // prepare VariableDeclarationList
     VariableDeclarationList declarationList =
@@ skipping 38 matching lines @@
     // type source might be null, if the type is private
     if (typeSource == null) {
       _coverageMarker();
       return;
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
     if (unitLibraryFile == file) {
       // TODO(brianwilkerson) Make ChangeBuilder merge multiple edits to the
       // same file so that only the else block is necessary.
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         Token keyword = declarationList.keyword;
         if (keyword?.keyword == Keyword.VAR) {
           builder.addSimpleReplacement(range.token(keyword), typeSource);
         } else {
           builder.addSimpleInsertion(variable.offset, '$typeSource ');
         }
         builder.importLibraries(librariesToImport);
       });
     } else {
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         Token keyword = declarationList.keyword;
         if (keyword?.keyword == Keyword.VAR) {
           builder.addSimpleReplacement(range.token(keyword), typeSource);
         } else {
           builder.addSimpleInsertion(variable.offset, '$typeSource ');
         }
       });
-      await changeBuilder
-          .addFileEdit(unitLibraryFile, _modificationStamp(unitLibraryFile),
-              (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(unitLibraryFile,
+          (DartFileEditBuilder builder) {
         builder.importLibraries(librariesToImport);
       });
     }
     _addAssistFromBuilder(changeBuilder, DartAssistKind.ADD_TYPE_ANNOTATION);
   }
 
   Future<Null> _addProposal_assignToLocalVariable() async {
     // prepare enclosing ExpressionStatement
     ExpressionStatement expressionStatement;
     for (AstNode node = this.node; node != null; node = node.parent) {
@@ skipping 25 matching lines @@
     // prepare excluded names
     Set<String> excluded = new Set<String>();
     ScopedNameFinder scopedNameFinder = new ScopedNameFinder(offset);
     expression.accept(scopedNameFinder);
     excluded.addAll(scopedNameFinder.locals.keys.toSet());
     List<String> suggestions =
         getVariableNameSuggestionsForExpression(type, expression, excluded);
 
     if (suggestions.isNotEmpty) {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addInsertion(offset, (DartEditBuilder builder) {
           builder.write('var ');
           builder.addSimpleLinkedEdit('NAME', suggestions[0],
               kind: LinkedEditSuggestionKind.VARIABLE,
               suggestions: suggestions);
           builder.write(' = ');
         });
       });
       _addAssistFromBuilder(
           changeBuilder, DartAssistKind.ASSIGN_TO_LOCAL_VARIABLE);
     }
   }
 
   Future<Null> _addProposal_convertDocumentationIntoBlock() async {
     Comment comment = node.getAncestor((n) => n is Comment);
     if (comment == null || !comment.isDocumentation) {
       return;
     }
     var tokens = comment.tokens;
     if (tokens.isEmpty ||
         tokens.any((Token token) =>
             token is! DocumentationCommentToken ||
             token.type != TokenType.SINGLE_LINE_COMMENT)) {
       return;
     }
     String prefix = utils.getNodePrefix(comment);
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addReplacement(range.node(comment), (DartEditBuilder builder) {
         builder.writeln('/**');
         for (Token token in comment.tokens) {
           builder.write(prefix);
           builder.write(' *');
           builder.writeln(token.lexeme.substring('///'.length));
         }
         builder.write(prefix);
         builder.write(' */');
       });
@@ skipping 43 matching lines @@
           _coverageMarker();
           return;
         }
         line = line.substring(expectedPrefix.length).trim();
         newLines.add('$linePrefix/// $line');
         linePrefix = eol + prefix;
       }
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addReplacement(range.node(comment), (DartEditBuilder builder) {
         for (String newLine in newLines) {
           builder.write(newLine);
         }
       });
     });
     _addAssistFromBuilder(
         changeBuilder, DartAssistKind.CONVERT_DOCUMENTATION_INTO_LINE);
   }
 
@@ skipping 26 matching lines @@
         _coverageMarker();
         return;
       }
     }
     InstanceCreationExpression childArg = getChildWidget(namedExp, false);
     if (childArg == null) {
       _coverageMarker();
       return;
     }
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       _convertFlutterChildToChildren(childArg, namedExp, eol, utils.getNodeText,
           utils.getLinePrefix, utils.getIndent, utils.getText, builder);
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.CONVERT_FLUTTER_CHILD);
   }
 
   Future<Null> _addProposal_convertIntoFinalField() async {
     // Find the enclosing getter.
     MethodDeclaration getter;
     for (AstNode n = node; n != null; n = n.parent) {
@@ skipping 48 matching lines @@
         beginNodeToReplace = getter.returnType;
         code += ' ' + _getNodeText(getter.returnType);
       }
       code += ' ' + _getNodeText(getter.name);
       if (expression is! NullLiteral) {
         code += ' = ' + _getNodeText(expression);
       }
       code += ';';
       SourceRange replacementRange = range.startEnd(beginNodeToReplace, getter);
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addSimpleReplacement(replacementRange, code);
       });
       _addAssistFromBuilder(
           changeBuilder, DartAssistKind.CONVERT_INTO_FINAL_FIELD);
     }
   }
 
   Future<Null> _addProposal_convertIntoGetter() async {
     // Find the enclosing field declaration.
     FieldDeclaration fieldDeclaration;
@@ skipping 30 matching lines @@
     if (fieldList.type != null) {
       code += _getNodeText(fieldList.type) + ' ';
     }
     code += 'get';
     code += ' ' + _getNodeText(field.name);
     code += ' => ' + _getNodeText(initializer);
     code += ';';
     SourceRange replacementRange =
         range.startEnd(fieldList.keyword, fieldDeclaration);
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addSimpleReplacement(replacementRange, code);
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.CONVERT_INTO_GETTER);
   }
 
   Future<Null> _addProposal_convertToBlockFunctionBody() async {
     FunctionBody body = getEnclosingFunctionBody();
     // prepare expression body
     if (body is! ExpressionFunctionBody || body.isGenerator) {
       _coverageMarker();
       return;
     }
     Expression returnValue = (body as ExpressionFunctionBody).expression;
     DartType returnValueType = returnValue.staticType;
     String returnValueCode = _getNodeText(returnValue);
     // prepare prefix
     String prefix = utils.getNodePrefix(body.parent);
     String indent = utils.getIndent(1);
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addReplacement(range.node(body), (DartEditBuilder builder) {
         if (body.isAsynchronous) {
           builder.write('async ');
         }
         builder.write('{$eol$prefix$indent');
         if (!returnValueType.isVoid) {
           builder.write('return ');
         }
         builder.write(returnValueCode);
         builder.write(';');
@@ skipping 25 matching lines @@
       returnExpression = onlyStatement.expression;
     } else if (onlyStatement is ExpressionStatement) {
       returnExpression = onlyStatement.expression;
     }
     if (returnExpression == null) {
       _coverageMarker();
       return;
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addReplacement(range.node(body), (DartEditBuilder builder) {
         if (body.isAsynchronous) {
           builder.write('async ');
         }
         builder.write('=> ');
         builder.write(_getNodeText(returnExpression));
         if (body.parent is! FunctionExpression ||
             body.parent.parent is FunctionDeclaration) {
           builder.write(';');
         }
@@ skipping 65 matching lines @@
             parameterInitializer = initializer;
           }
         }
       }
       if (parameterInitializer == null) {
         return;
       }
       String fieldName = parameterInitializer.fieldName.name;
 
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         // replace parameter
         builder.addSimpleReplacement(range.node(parameter), 'this.$fieldName');
         // remove initializer
         int initializerIndex = initializers.indexOf(parameterInitializer);
         if (initializers.length == 1) {
           builder
               .addDeletion(range.endEnd(parameterList, parameterInitializer));
         } else {
           if (initializerIndex == 0) {
             ConstructorInitializer next = initializers[initializerIndex + 1];
@@ skipping 69 matching lines @@
         _coverageMarker();
         return;
       }
     }
     // prepare environment
     String prefix = utils.getNodePrefix(forEachStatement);
     String indent = utils.getIndent(1);
     int firstBlockLine = utils.getLineContentEnd(body.leftBracket.end);
     // add change
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       // TODO(brianwilkerson) Create linked positions for the loop variable.
       builder.addSimpleReplacement(
           range.startEnd(forEachStatement, forEachStatement.rightParenthesis),
           'for (int $indexName = 0; $indexName < $listName.length; $indexName++)');
       builder.addSimpleInsertion(firstBlockLine,
           '$prefix$indent$loopVariable = $listName[$indexName];$eol');
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.CONVERT_INTO_FOR_INDEX);
   }
 
@@ skipping 26 matching lines @@
       _coverageMarker();
       return;
     }
     PrefixExpression prefExpression = parent2 as PrefixExpression;
     if (prefExpression.operator.type != TokenType.BANG) {
       _coverageMarker();
       return;
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       if (getExpressionParentPrecedence(prefExpression) >=
           TokenClass.RELATIONAL_OPERATOR.precedence) {
         builder.addDeletion(range.token(prefExpression.operator));
       } else {
         builder.addDeletion(
             range.startEnd(prefExpression, parExpression.leftParenthesis));
         builder.addDeletion(
             range.startEnd(parExpression.rightParenthesis, prefExpression));
       }
       builder.addSimpleInsertion(isExpression.isOperator.end, '!');
@@ skipping 30 matching lines @@
       _coverageMarker();
       return;
     }
     IsExpression isExpression = operand as IsExpression;
     if (isExpression.notOperator != null) {
       _coverageMarker();
       return;
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       if (getExpressionParentPrecedence(prefExpression) >=
           TokenClass.RELATIONAL_OPERATOR.precedence) {
         builder.addDeletion(range.token(prefExpression.operator));
       } else {
         builder.addDeletion(
             range.startEnd(prefExpression, parExpression.leftParenthesis));
         builder.addDeletion(
             range.startEnd(parExpression.rightParenthesis, prefExpression));
       }
       builder.addSimpleInsertion(isExpression.isOperator.end, '!');
@@ skipping 46 matching lines @@
     }
     PrefixExpression prefixExpression =
         isEmptyAccess.parent as PrefixExpression;
     // should be !
     if (prefixExpression.operator.type != TokenType.BANG) {
       _coverageMarker();
       return;
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addDeletion(
           range.startStart(prefixExpression, prefixExpression.operand));
       builder.addSimpleReplacement(range.node(isEmptyIdentifier), 'isNotEmpty');
     });
     _addAssistFromBuilder(
         changeBuilder, DartAssistKind.CONVERT_INTO_IS_NOT_EMPTY);
   }
 
   Future<Null> _addProposal_convertToNormalParameter() async {
     if (node is SimpleIdentifier &&
         node.parent is FieldFormalParameter &&
         node.parent.parent is FormalParameterList &&
         node.parent.parent.parent is ConstructorDeclaration) {
       ConstructorDeclaration constructor = node.parent.parent.parent;
       FormalParameterList parameterList = node.parent.parent;
       FieldFormalParameter parameter = node.parent;
       ParameterElement parameterElement = parameter.element;
       String name = (node as SimpleIdentifier).name;
       // prepare type
       DartType type = parameterElement.type;
       Set<Source> librariesToImport = new Set<Source>();
       String typeCode = utils.getTypeSource(type, librariesToImport);
 
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         // replace parameter
         if (type.isDynamic) {
           builder.addSimpleReplacement(range.node(parameter), name);
         } else {
           builder.addSimpleReplacement(
               range.node(parameter), '$typeCode $name');
         }
         // add field initializer
         List<ConstructorInitializer> initializers = constructor.initializers;
         if (initializers.isEmpty) {
@@ skipping 45 matching lines @@
     if (Identifier.isPrivateName(name)) {
       _coverageMarker();
       return;
     }
     // should be on the name
     if (nameNode != node) {
       _coverageMarker();
       return;
     }
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       // rename field
       builder.addSimpleReplacement(range.node(nameNode), '_$name');
       // update references in constructors
       ClassDeclaration classDeclaration = fieldDeclaration.parent;
       for (ClassMember member in classDeclaration.members) {
         if (member is ConstructorDeclaration) {
           for (FormalParameter parameter in member.parameters.parameters) {
             ParameterElement parameterElement = parameter.element;
             if (parameterElement is FieldFormalParameterElement &&
                 parameterElement.field == fieldElement) {
@@ skipping 55 matching lines @@
     if (operatorType == TokenType.LT) {
       newOperator = '>';
     } else if (operatorType == TokenType.LT_EQ) {
       newOperator = '>=';
     } else if (operatorType == TokenType.GT) {
       newOperator = '<';
     } else if (operatorType == TokenType.GT_EQ) {
       newOperator = '<=';
     }
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addSimpleReplacement(leftRange, _getRangeText(rightRange));
       builder.addSimpleReplacement(rightRange, _getRangeText(leftRange));
       // Optionally replace the operator.
       if (newOperator != null) {
         builder.addSimpleReplacement(range.token(operator), newOperator);
       }
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.EXCHANGE_OPERANDS);
   }
 
@@ skipping 26 matching lines @@
         referencedNames.add(element.displayName);
       }
     });
     unit.accept(visitor);
     // ignore if unused
     if (referencedNames.isEmpty) {
       _coverageMarker();
       return;
     }
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       String showCombinator = ' show ${referencedNames.join(', ')}';
       builder.addSimpleInsertion(importDirective.end - 1, showCombinator);
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.IMPORT_ADD_SHOW);
   }
 
   Future<Null> _addProposal_introduceLocalTestedType() async {
     AstNode node = this.node;
     if (node is IfStatement) {
       node = (node as IfStatement).condition;
@@ skipping 38 matching lines @@
     Set<String> excluded = new Set<String>();
     ScopedNameFinder scopedNameFinder = new ScopedNameFinder(offset);
     isExpression.accept(scopedNameFinder);
     excluded.addAll(scopedNameFinder.locals.keys.toSet());
     // name(s)
     List<String> suggestions =
         getVariableNameSuggestionsForExpression(castType, null, excluded);
 
     if (suggestions.isNotEmpty) {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addInsertion(offset, (DartEditBuilder builder) {
           builder.write(eol + prefix + statementPrefix);
           builder.write(castTypeCode);
           builder.write(' ');
           builder.addSimpleLinkedEdit('NAME', suggestions[0],
               kind: LinkedEditSuggestionKind.VARIABLE,
               suggestions: suggestions);
           builder.write(' = ');
           builder.write(_getNodeText(isExpression.expression));
           builder.write(';');
@@ skipping 16 matching lines @@
     Statement elseStatement = ifStatement.elseStatement;
     if (thenStatement == null || elseStatement == null) {
       return;
     }
     // prepare source
     String invertedCondition = utils.invertCondition(condition);
     String thenSource = _getNodeText(thenStatement);
     String elseSource = _getNodeText(elseStatement);
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addSimpleReplacement(range.node(condition), invertedCondition);
       builder.addSimpleReplacement(range.node(thenStatement), elseSource);
       builder.addSimpleReplacement(range.node(elseStatement), thenSource);
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.INVERT_IF_STATEMENT);
   }
 
   Future<Null> _addProposal_joinIfStatementInner() async {
     // climb up condition to the (supposedly) "if" statement
     AstNode node = this.node;
@@ skipping 40 matching lines @@
       condition = '$targetConditionSource && $innerConditionSource';
     }
     // replace target "if" statement
     Statement innerThenStatement = innerIfStatement.thenStatement;
     List<Statement> innerThenStatements = getStatements(innerThenStatement);
     SourceRange lineRanges = utils.getLinesRangeStatements(innerThenStatements);
     String oldSource = utils.getRangeText(lineRanges);
     String newSource = utils.indentSourceLeftRight(oldSource, false);
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addSimpleReplacement(range.node(targetIfStatement),
           'if ($condition) {$eol$newSource$prefix}');
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.JOIN_IF_WITH_INNER);
   }
 
   Future<Null> _addProposal_joinIfStatementOuter() async {
     // climb up condition to the (supposedly) "if" statement
     AstNode node = this.node;
     while (node is Expression) {
@@ skipping 43 matching lines @@
     String condition = '$outerConditionSource && $targetConditionSource';
     // replace outer "if" statement
     Statement targetThenStatement = targetIfStatement.thenStatement;
     List<Statement> targetThenStatements = getStatements(targetThenStatement);
     SourceRange lineRanges =
         utils.getLinesRangeStatements(targetThenStatements);
     String oldSource = utils.getRangeText(lineRanges);
     String newSource = utils.indentSourceLeftRight(oldSource, false);
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addSimpleReplacement(range.node(outerIfStatement),
           'if ($condition) {$eol$newSource$prefix}');
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.JOIN_IF_WITH_OUTER);
   }
 
   Future<Null> _addProposal_joinVariableDeclaration_onAssignment() async {
     // check that node is LHS in assignment
     if (node is SimpleIdentifier &&
         node.parent is AssignmentExpression &&
@@ skipping 49 matching lines @@
     Block block = assignStatement.parent as Block;
     // check that "declaration" and "assignment" statements are adjacent
     List<Statement> statements = block.statements;
     if (statements.indexOf(assignStatement) ==
         statements.indexOf(declStatement) + 1) {} else {
       _coverageMarker();
       return;
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addSimpleReplacement(
           range.endStart(declNode, assignExpression.operator), ' ');
     });
     _addAssistFromBuilder(
         changeBuilder, DartAssistKind.JOIN_VARIABLE_DECLARATION);
   }
 
   Future<Null> _addProposal_joinVariableDeclaration_onDeclaration() async {
     // prepare enclosing VariableDeclarationList
     VariableDeclarationList declList =
@@ skipping 42 matching lines @@
       }
       assignExpression = expressionStatement.expression as AssignmentExpression;
     }
     // check that pure assignment
     if (assignExpression.operator.type != TokenType.EQ) {
       _coverageMarker();
       return;
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addSimpleReplacement(
           range.endStart(decl.name, assignExpression.operator), ' ');
     });
     _addAssistFromBuilder(
         changeBuilder, DartAssistKind.JOIN_VARIABLE_DECLARATION);
   }
 
   Future<Null> _addProposal_moveFlutterWidgetDown() async {
     InstanceCreationExpression exprGoingDown = identifyNewExpression(node);
     if (exprGoingDown == null ||
@@ skipping 82 matching lines @@
     }
     // must be not after the name of the variable
     VariableDeclaration firstVariable = declarationList.variables[0];
     if (selectionOffset > firstVariable.name.end) {
       _coverageMarker();
       return;
     }
     // add edit
     Token keyword = declarationList.keyword;
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       SourceRange typeRange = range.startStart(typeNode, firstVariable);
       if (keyword != null && keyword.lexeme != 'var') {
         builder.addSimpleReplacement(typeRange, '');
       } else {
         builder.addSimpleReplacement(typeRange, 'var ');
       }
     });
     _addAssistFromBuilder(changeBuilder, DartAssistKind.REMOVE_TYPE_ANNOTATION);
   }
 
@@ skipping 11 matching lines @@
     int newlineIdx = literalSrc.lastIndexOf(eol);
     if (newlineIdx < 0 || newlineIdx == literalSrc.length - 1) {
       _coverageMarker();
       return; // Lists need to be in multi-line format already.
     }
     String indentOld = utils.getLinePrefix(node.offset + 1 + newlineIdx);
     String indentArg = '$indentOld${utils.getIndent(1)}';
     String indentList = '$indentOld${utils.getIndent(2)}';
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addReplacement(range.node(node), (DartEditBuilder builder) {
         builder.write('[');
         builder.write(eol);
         builder.write(indentArg);
         builder.write('new ');
         builder.addSimpleLinkedEdit('WIDGET', 'widget');
         builder.write('(');
         builder.write(eol);
         builder.write(indentList);
         // Linked editing not needed since arg is always a list.
@@ skipping 15 matching lines @@
 
   Future<Null> _addProposal_reparentFlutterWidget() async {
     InstanceCreationExpression newExpr = identifyNewExpression(node);
     if (newExpr == null || !isFlutterInstanceCreationExpression(newExpr)) {
       _coverageMarker();
       return;
     }
     String newExprSrc = utils.getNodeText(newExpr);
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addReplacement(range.node(newExpr), (DartEditBuilder builder) {
         builder.write('new ');
         builder.addSimpleLinkedEdit('WIDGET', 'widget');
         builder.write('(');
         if (newExprSrc.contains(eol)) {
           int newlineIdx = newExprSrc.lastIndexOf(eol);
           int eolLen = eol.length;
           if (newlineIdx == newExprSrc.length - eolLen) {
             newlineIdx -= eolLen;
           }
@@ skipping 60 matching lines @@
         conditional = returnStatement.expression as ConditionalExpression;
         inReturn = true;
       }
     }
     // prepare environment
     String indent = utils.getIndent(1);
     String prefix = utils.getNodePrefix(statement);
 
     if (inVariable || inAssignment || inReturn) {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         // Type v = Conditional;
         if (inVariable) {
           VariableDeclaration variable =
               conditional.parent as VariableDeclaration;
           builder.addDeletion(range.endEnd(variable.name, conditional));
           String conditionSrc = _getNodeText(conditional.condition);
           String thenSrc = _getNodeText(conditional.thenExpression);
           String elseSrc = _getNodeText(conditional.elseExpression);
           String name = variable.name.name;
           String src = eol;
@@ skipping 68 matching lines @@
       if (thenStatement.expression is AssignmentExpression &&
           elseStatement.expression is AssignmentExpression) {
         hasExpressionStatements = true;
         thenExpression = thenStatement.expression;
         elseExpression = elseStatement.expression;
       }
     }
 
     if (hasReturnStatements || hasExpressionStatements) {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         // returns
         if (hasReturnStatements) {
           String conditionSrc = _getNodeText(ifStatement.condition);
           String theSrc = _getNodeText(thenExpression);
           String elseSrc = _getNodeText(elseExpression);
           builder.addSimpleReplacement(range.node(ifStatement),
               'return $conditionSrc ? $theSrc : $elseSrc;');
         }
         // assignments -> v = Conditional;
         if (hasExpressionStatements) {
@@ skipping 63 matching lines @@
     String indent = utils.getIndent(1);
     // prepare "rightCondition"
     String rightConditionSource;
     {
       SourceRange rightConditionRange =
           range.startEnd(binaryExpression.rightOperand, condition);
       rightConditionSource = _getRangeText(rightConditionRange);
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       // remove "&& rightCondition"
       builder
           .addDeletion(range.endEnd(binaryExpression.leftOperand, condition));
       // update "then" statement
       Statement thenStatement = ifStatement.thenStatement;
       if (thenStatement is Block) {
         Block thenBlock = thenStatement;
         SourceRange thenBlockRange = range.node(thenBlock);
         // insert inner "if" with right part of "condition"
         int thenBlockInsideOffset = thenBlockRange.offset + 1;
@@ skipping 39 matching lines @@
       return;
     }
     VariableDeclaration variable = variables[0];
     // prepare initializer
     Expression initializer = variable.initializer;
     if (initializer == null) {
       _coverageMarker();
       return;
     }
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       // remove initializer value
       builder.addDeletion(range.endStart(variable.name, statement.semicolon));
       // add assignment statement
       String indent = utils.getNodePrefix(statement);
       String name = variable.name.name;
       String initSrc = _getNodeText(initializer);
       SourceRange assignRange = range.endLength(statement, 0);
       builder.addSimpleReplacement(
           assignRange, eol + indent + name + ' = ' + initSrc + ';');
     });
@@ skipping 28 matching lines @@
     SourceRange statementsRange =
         utils.getLinesRangeStatements(selectedStatements);
     // prepare environment
     String indentOld = utils.getNodePrefix(firstStatement);
     String indentNew = '$indentOld${utils.getIndent(1)}';
     String indentedCode =
         utils.replaceSourceRangeIndent(statementsRange, indentOld, indentNew);
     // "block"
     {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addSimpleInsertion(statementsRange.offset, '$indentOld{$eol');
         builder.addSimpleReplacement(
             statementsRange,
             utils.replaceSourceRangeIndent(
                 statementsRange, indentOld, indentNew));
         builder.addSimpleInsertion(statementsRange.end, '$indentOld}$eol');
         exitPosition = _newPosition(lastStatement.end);
       });
       _addAssistFromBuilder(changeBuilder, DartAssistKind.SURROUND_WITH_BLOCK);
     }
     // "if"
     {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addReplacement(statementsRange, (DartEditBuilder builder) {
           builder.write(indentOld);
           builder.write('if (');
           builder.addSimpleLinkedEdit('CONDITION', 'condition');
           builder.write(') {');
           builder.write(eol);
           builder.write(indentedCode);
           builder.write(indentOld);
           builder.write('}');
           builder.selectHere();
           builder.write(eol);
         });
       });
       _addAssistFromBuilder(changeBuilder, DartAssistKind.SURROUND_WITH_IF);
     }
     // "while"
     {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addReplacement(statementsRange, (DartEditBuilder builder) {
           builder.write(indentOld);
           builder.write('while (');
           builder.addSimpleLinkedEdit('CONDITION', 'condition');
           builder.write(') {');
           builder.write(eol);
           builder.write(indentedCode);
           builder.write(indentOld);
           builder.write('}');
           builder.selectHere();
           builder.write(eol);
         });
       });
       _addAssistFromBuilder(changeBuilder, DartAssistKind.SURROUND_WITH_WHILE);
     }
     // "for-in"
     {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addReplacement(statementsRange, (DartEditBuilder builder) {
           builder.write(indentOld);
           builder.write('for (var ');
           builder.addSimpleLinkedEdit('NAME', 'item');
           builder.write(' in ');
           builder.addSimpleLinkedEdit('ITERABLE', 'iterable');
           builder.write(') {');
           builder.write(eol);
           builder.write(indentedCode);
           builder.write(indentOld);
           builder.write('}');
           builder.selectHere();
           builder.write(eol);
         });
       });
       _addAssistFromBuilder(changeBuilder, DartAssistKind.SURROUND_WITH_FOR_IN);
     }
     // "for"
     {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addReplacement(statementsRange, (DartEditBuilder builder) {
           builder.write(indentOld);
           builder.write('for (var ');
           builder.addSimpleLinkedEdit('VAR', 'v');
           builder.write(' = ');
           builder.addSimpleLinkedEdit('INIT', 'init');
           builder.write('; ');
           builder.addSimpleLinkedEdit('CONDITION', 'condition');
           builder.write('; ');
           builder.addSimpleLinkedEdit('INCREMENT', 'increment');
           builder.write(') {');
           builder.write(eol);
           builder.write(indentedCode);
           builder.write(indentOld);
           builder.write('}');
           builder.selectHere();
           builder.write(eol);
         });
       });
       _addAssistFromBuilder(changeBuilder, DartAssistKind.SURROUND_WITH_FOR);
     }
     // "do-while"
     {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addReplacement(statementsRange, (DartEditBuilder builder) {
           builder.write(indentOld);
           builder.write('do {');
           builder.write(eol);
           builder.write(indentedCode);
           builder.write(indentOld);
           builder.write('} while (');
           builder.addSimpleLinkedEdit('CONDITION', 'condition');
           builder.write(');');
           builder.selectHere();
           builder.write(eol);
         });
       });
       _addAssistFromBuilder(
           changeBuilder, DartAssistKind.SURROUND_WITH_DO_WHILE);
     }
     // "try-catch"
     {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addReplacement(statementsRange, (DartEditBuilder builder) {
           builder.write(indentOld);
           builder.write('try {');
           builder.write(eol);
           builder.write(indentedCode);
           builder.write(indentOld);
           builder.write('} on ');
           builder.addSimpleLinkedEdit('EXCEPTION_TYPE', 'Exception');
           builder.write(' catch (');
           builder.addSimpleLinkedEdit('EXCEPTION_VAR', 'e');
           builder.write(') {');
           builder.write(eol);
           //
           builder.write(indentNew);
           builder.addSimpleLinkedEdit('CATCH', '// TODO');
           builder.selectHere();
           builder.write(eol);
           //
           builder.write(indentOld);
           builder.write('}');
           builder.write(eol);
         });
       });
       _addAssistFromBuilder(
           changeBuilder, DartAssistKind.SURROUND_WITH_TRY_CATCH);
     }
     // "try-finally"
     {
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-      await changeBuilder.addFileEdit(file, fileStamp,
-          (DartFileEditBuilder builder) {
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         builder.addReplacement(statementsRange, (DartEditBuilder builder) {
           builder.write(indentOld);
           builder.write('try {');
           builder.write(eol);
           //
           builder.write(indentedCode);
           //
           builder.write(indentOld);
           builder.write('} finally {');
           builder.write(eol);
@@ skipping 77 matching lines @@
     return utils.getNodeText(node);
   }
 
   /**
    * Returns the text of the given range in the unit.
    */
   String _getRangeText(SourceRange range) {
     return utils.getRangeText(range);
   }
 
-  int _modificationStamp(String filePath) {
-    // TODO(brianwilkerson) We have lost the ability for clients to know whether
-    // it is safe to apply an edit.
-    return driver.fsState.getFileForPath(filePath).exists ? 0 : -1;
-  }
-
   Position _newPosition(int offset) {
     return new Position(file, offset);
   }
 
   Future<Null> _swapFlutterWidgets(
       InstanceCreationExpression exprGoingDown,
       InstanceCreationExpression exprGoingUp,
       NamedExpression stableChild,
       AssistKind assistKind) async {
     String currentSource = unitElement.context.getContents(source).data;
     // TODO(messick) Find a better way to get LineInfo for the source.
     LineInfo lineInfo = new LineInfo.fromContent(currentSource);
     int currLn = lineInfo.getLocation(exprGoingUp.offset).lineNumber;
     int lnOffset = lineInfo.getOffsetOfLine(currLn);
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addReplacement(range.node(exprGoingDown),
           (DartEditBuilder builder) {
         String argSrc =
             utils.getText(exprGoingUp.offset, lnOffset - exprGoingUp.offset);
         builder.write(argSrc); // Append child new-expr plus rest of line.
 
         String getSrc(Expression expr) {
           int startLn = lineInfo.getLocation(expr.offset).lineNumber;
           int startOffset = lineInfo.getOffsetOfLine(startLn - 1);
           int endLn =
@@ skipping 130 matching lines @@
 class _SimpleIdentifierRecursiveAstVisitor extends RecursiveAstVisitor {
   final _SimpleIdentifierVisitor visitor;
 
   _SimpleIdentifierRecursiveAstVisitor(this.visitor);
 
   @override
   visitSimpleIdentifier(SimpleIdentifier node) {
     visitor(node);
   }
 }