Move SourceReference, extract duplicate code.

pkg/analysis_server/lib/src/services/refactoring/refactoring_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.
 
 library services.src.refactoring;
 
 import 'dart:async';
+import 'dart:collection';
 
+import 'package:analysis_server/src/protocol.dart' hide Element;
 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/src/generated/element.dart';
+import 'package:analyzer/src/generated/source.dart';
 
 
 /**
+ * When a [Source] (a file) is used in more than one context, [SearchEngine]
+ * will return separate [SearchMatch]s for each context. But in rename
+ * refactorings we want to update each [Source] only once.
+ */
+List<SourceReference> getSourceReferences(List<SearchMatch> matches) {
+  var uniqueReferences = new HashMap<SourceReference, SourceReference>();
+  for (SearchMatch match in matches) {
+    Element element = match.element;
+    String file = element.source.fullName;
+    SourceRange range = match.sourceRange;
+    SourceReference newReference =
+        new SourceReference(file, range, element, match.isResolved, match.isQualified);
+    SourceReference oldReference = uniqueReferences[newReference];
+    if (oldReference == null) {
+      uniqueReferences[newReference] = newReference;
+      oldReference = newReference;
+    }
+  }
+  return uniqueReferences.keys.toList();
+}
+
+
+/**
  * Abstract implementation of [Refactoring].
  */
 abstract class RefactoringImpl implements Refactoring {
   final List<String> potentialEditIds = <String>[];
 
   @override
   Future<RefactoringStatus> checkAllConditions() {
     RefactoringStatus result = new RefactoringStatus();
     return checkInitialConditions().then((status) {
       result.addStatus(status);
       if (result.hasFatalError) {
         return result;
       }
       return checkFinalConditions().then((status) {
         result.addStatus(status);
         return result;
       });
     });
   }
 }
+
+
+/**
+ * The [SourceRange] in some [Source].
+ */
+class SourceReference {
+  final String file;
+  final SourceRange range;
+  final Element element;
+  final bool isResolved;
+  final bool isQualified;
+
+  SourceReference(this.file, this.range, this.element, this.isResolved,
+      this.isQualified);
+
+  @override
+  int get hashCode {
+    int hash = file.hashCode;
+    hash = ((hash << 16) & 0xFFFFFFFF) + range.hashCode;
+    return hash;
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(other, this)) {
+      return true;
+    }
+    if (other is SourceReference) {
+      return other.file == file && other.range == range;
+    }
+    return false;
+  }
+
+  /**
+   * Adds the [SourceEdit] to replace this reference.
+   */
+  void addEdit(SourceChange change, String newText, {String id}) {
+    SourceEdit edit = createEdit(newText, id: id);
+    change.addElementEdit(element, edit);
+  }
+
+  /**
+   * Returns the [SourceEdit] to replace this reference.
+   */
+  SourceEdit createEdit(String newText, {String id}) {
+    return new SourceEdit.range(range, newText, id: id);
+  }
+
+  @override
+  String toString() => '${file}@${range}';
+}