Remove timeStamp from the ChangeBuilder API

pkg/analysis_server/lib/src/services/completion/postfix/postfix_completion.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 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/util.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 262 matching lines @@
 /**
  * The computer for Dart postfix completions.
  */
 class PostfixCompletionProcessor {
   static final NO_COMPLETION = new PostfixCompletion(
       DartPostfixCompletion.NO_TEMPLATE, new SourceChange("", edits: []));
 
   final PostfixCompletionContext completionContext;
   final AnalysisContext analysisContext;
   final CorrectionUtils utils;
-  int fileStamp;
   AstNode node;
   PostfixCompletion completion;
   SourceChange change = new SourceChange('postfix-completion');
   final Map<String, LinkedEditGroup> linkedPositionGroups =
       <String, LinkedEditGroup>{};
   Position exitPosition = null;
   TypeProvider _typeProvider;
 
   PostfixCompletionProcessor(this.completionContext)
       : analysisContext = completionContext.unitElement.context,
-        utils = new CorrectionUtils(completionContext.unit) {
-    fileStamp = _modificationStamp(file);
-  }
+        utils = new CorrectionUtils(completionContext.unit);
 
   AnalysisDriver get driver => completionContext.driver;
 
   String get eol => utils.endOfLine;
 
   String get file => completionContext.file;
 
   String get key => completionContext.key;
 
   LineInfo get lineInfo => completionContext.lineInfo;
 
   int get requestLine => lineInfo.getLocation(selectionOffset).lineNumber;
 
   int get selectionOffset => completionContext.selectionOffset;
 
   Source get source => completionContext.unitElement.source;
 
   TypeProvider get typeProvider {
     return _typeProvider ??= unitElement.context.typeProvider;
   }
 
   CompilationUnit get unit => completionContext.unit;
 
   CompilationUnitElement get unitElement => completionContext.unitElement;
 
   Future<PostfixCompletion> 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 NO_COMPLETION;
-    }
     node = _selectedNode();
     if (node == null) {
       return NO_COMPLETION;
     }
     PostfixCompletionKind completer = DartPostfixCompletion.forKey(key);
     return completer?.computer(this, completer) ?? NO_COMPLETION;
   }
 
   Future<PostfixCompletion> expand(
       PostfixCompletionKind kind, Function contexter, Function sourcer,
       {bool withBraces: true}) async {
     AstNode expr = contexter();
     if (expr == null) {
       return null;
     }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       builder.addReplacement(range.node(expr), (DartEditBuilder builder) {
         String newSrc = sourcer(expr);
         if (newSrc == null) {
           return null;
         }
         builder.write(newSrc);
         if (withBraces) {
           builder.write(" {");
           builder.write(eol);
           String indent = utils.getNodePrefix(expr);
@@ skipping 13 matching lines @@
   }
 
   Future<PostfixCompletion> expandTry(
       PostfixCompletionKind kind, Function contexter,
       {bool withOn: false}) async {
     AstNode stmt = contexter();
     if (stmt == null) {
       return null;
     }
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    await changeBuilder.addFileEdit(file, fileStamp,
-        (DartFileEditBuilder builder) {
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       // Embed the full line(s) of the statement in the try block.
       var startLine = lineInfo.getLocation(stmt.offset).lineNumber - 1;
       var endLine = lineInfo.getLocation(stmt.end).lineNumber - 1;
       if (stmt is ExpressionStatement && !stmt.semicolon.isSynthetic) {
         endLine += 1;
       }
       var startOffset = lineInfo.getOffsetOfLine(startLine);
       var endOffset = lineInfo.getOffsetOfLine(endLine);
       var src = utils.getText(startOffset, endOffset - startOffset);
       String indent = utils.getLinePrefix(stmt.offset);
@@ skipping 78 matching lines @@
           return null;
         }
         return astNode;
       }
       astNode = astNode.parent;
     }
     return null;
   }
 
   Future<bool> isApplicable() async {
-    if (_modificationStamp(file) != fileStamp) {
-      return false;
-    }
     node = _selectedNode();
     if (node == null) {
       return false;
     }
     PostfixCompletionKind completer = DartPostfixCompletion.forKey(key);
     return completer?.selector(this);
   }
 
   String makeNegatedBoolExpr(Expression expr) {
     String originalSrc = utils.getNodeText(expr);
@@ skipping 60 matching lines @@
     }, orElse: () => null);
     if (expr is SimpleIdentifier && expr.parent is PropertyAccess) {
       expr = expr.parent;
     }
     if (expr?.parent is CascadeExpression) {
       expr = expr.parent;
     }
     return expr;
   }
 
-  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;
-  }
-
   AstNode _selectedNode({int at: null}) =>
       new NodeLocator(at == null ? selectionOffset : at).searchWithin(unit);
 
   void _setCompletionFromBuilder(
       DartChangeBuilder builder, PostfixCompletionKind kind,
       [List args]) {
     SourceChange change = builder.sourceChange;
     if (change.edits.isEmpty) {
       completion = null;
       return;
     }
     change.message = formatList(kind.message, args);
     completion = new PostfixCompletion(kind, change);
   }
 }