Reduce duplicated code

pkg/analysis_server/lib/src/computer/computer_outline.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 'package:analysis_server/src/collections.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart' as engine;
 import 'package:analyzer/dart/element/type.dart' as engine;
 import 'package:analyzer/src/generated/source.dart';
@@ skipping 94 matching lines @@
   Location _getLocationOffsetLength(int offset, int length) {
     LineInfo_Location lineLocation = lineInfo.getLocation(offset);
     int startLine = lineLocation.lineNumber;
     int startColumn = lineLocation.columnNumber;
     return new Location(file, offset, length, startLine, startColumn);
   }
 
   /**
    * Returns the [AstNode]'s source region.
    */
-  _SourceRegion _getSourceRegion(AstNode node) {
+  SourceRange _getSourceRange(AstNode node) {
     int endOffset = node.end;
     // prepare position of the node among its siblings
     int firstOffset;
     List<AstNode> siblings;
     AstNode parent = node.parent;
     // field
     if (parent is VariableDeclarationList) {
       VariableDeclarationList variableList = parent as VariableDeclarationList;
       List<VariableDeclaration> variables = variableList.variables;
       int variableIndex = variables.indexOf(node);
       if (variableIndex == variables.length - 1) {
         endOffset = variableList.parent.end;
       }
       if (variableIndex == 0) {
         node = parent.parent;
         parent = node.parent;
       } else if (variableIndex >= 1) {
         firstOffset = variables[variableIndex - 1].end;
-        return new _SourceRegion(firstOffset, endOffset - firstOffset);
+        return new SourceRange(firstOffset, endOffset - firstOffset);
       }
     }
     // unit or class member
     if (parent is CompilationUnit) {
       firstOffset = node.offset;
       siblings = parent.declarations;
     } else if (parent is ClassDeclaration) {
       firstOffset = parent.leftBracket.end;
       siblings = parent.members;
     } else {
       int offset = node.offset;
-      return new _SourceRegion(offset, endOffset - offset);
+      return new SourceRange(offset, endOffset - offset);
     }
     // first child: [endOfParent, endOfNode]
     int index = siblings.indexOf(node);
     if (index == 0) {
-      return new _SourceRegion(firstOffset, endOffset - firstOffset);
+      return new SourceRange(firstOffset, endOffset - firstOffset);
     }
     // not first child: [endOfPreviousSibling, endOfNode]
     int prevSiblingEnd = siblings[index - 1].end;
-    return new _SourceRegion(prevSiblingEnd, endOffset - prevSiblingEnd);
+    return new SourceRange(prevSiblingEnd, endOffset - prevSiblingEnd);
   }
 
   Outline _newClassOutline(ClassDeclaration node, List<Outline> classContents) {
     SimpleIdentifier nameNode = node.name;
     String name = nameNode.name;
-    _SourceRegion sourceRegion = _getSourceRegion(node);
+    SourceRange range = _getSourceRange(node);
     Element element = new Element(
         ElementKind.CLASS,
         name,
         Element.makeFlags(
             isPrivate: Identifier.isPrivateName(name),
             isDeprecated: _isDeprecated(node),
             isAbstract: node.isAbstract),
         location: _getLocationNode(nameNode),
         typeParameters: _getTypeParametersStr(node.typeParameters));
-    return new Outline(element, sourceRegion.offset, sourceRegion.length,
+    return new Outline(element, range.offset, range.length,
         children: nullIfEmpty(classContents));
   }
 
   Outline _newClassTypeAlias(ClassTypeAlias node) {
     SimpleIdentifier nameNode = node.name;
     String name = nameNode.name;
-    _SourceRegion sourceRegion = _getSourceRegion(node);
+    SourceRange range = _getSourceRange(node);
     Element element = new Element(
         ElementKind.CLASS_TYPE_ALIAS,
         name,
         Element.makeFlags(
             isPrivate: Identifier.isPrivateName(name),
             isDeprecated: _isDeprecated(node),
             isAbstract: node.isAbstract),
         location: _getLocationNode(nameNode),
         typeParameters: _getTypeParametersStr(node.typeParameters));
-    return new Outline(element, sourceRegion.offset, sourceRegion.length);
+    return new Outline(element, range.offset, range.length);
   }
 
   Outline _newConstructorOutline(ConstructorDeclaration constructor) {
     Identifier returnType = constructor.returnType;
     String name = returnType.name;
     int offset = returnType.offset;
     int length = returnType.length;
     SimpleIdentifier constructorNameNode = constructor.name;
     bool isPrivate = false;
     if (constructorNameNode != null) {
       String constructorName = constructorNameNode.name;
       isPrivate = Identifier.isPrivateName(constructorName);
       name += '.$constructorName';
       offset = constructorNameNode.offset;
       length = constructorNameNode.length;
     }
-    _SourceRegion sourceRegion = _getSourceRegion(constructor);
+    SourceRange range = _getSourceRange(constructor);
     FormalParameterList parameters = constructor.parameters;
     String parametersStr = _safeToSource(parameters);
     Element element = new Element(
         ElementKind.CONSTRUCTOR,
         name,
         Element.makeFlags(
             isPrivate: isPrivate, isDeprecated: _isDeprecated(constructor)),
         location: _getLocationOffsetLength(offset, length),
         parameters: parametersStr);
     List<Outline> contents = _addLocalFunctionOutlines(constructor.body);
-    Outline outline = new Outline(
-        element, sourceRegion.offset, sourceRegion.length,
+    Outline outline = new Outline(element, range.offset, range.length,
         children: nullIfEmpty(contents));
     return outline;
   }
 
   Outline _newEnumConstant(EnumConstantDeclaration node) {
     SimpleIdentifier nameNode = node.name;
     String name = nameNode.name;
-    _SourceRegion sourceRegion = _getSourceRegion(node);
+    SourceRange range = _getSourceRange(node);
     Element element = new Element(
         ElementKind.ENUM_CONSTANT,
         name,
         Element.makeFlags(
             isPrivate: Identifier.isPrivateName(name),
             isDeprecated: _isDeprecated(node)),
         location: _getLocationNode(nameNode));
-    return new Outline(element, sourceRegion.offset, sourceRegion.length);
+    return new Outline(element, range.offset, range.length);
   }
 
   Outline _newEnumOutline(EnumDeclaration node, List<Outline> children) {
     SimpleIdentifier nameNode = node.name;
     String name = nameNode.name;
-    _SourceRegion sourceRegion = _getSourceRegion(node);
+    SourceRange range = _getSourceRange(node);
     Element element = new Element(
         ElementKind.ENUM,
         name,
         Element.makeFlags(
             isPrivate: Identifier.isPrivateName(name),
             isDeprecated: _isDeprecated(node)),
         location: _getLocationNode(nameNode));
-    return new Outline(element, sourceRegion.offset, sourceRegion.length,
+    return new Outline(element, range.offset, range.length,
         children: nullIfEmpty(children));
   }
 
   Outline _newFunctionOutline(FunctionDeclaration function, bool isStatic) {
     TypeAnnotation returnType = function.returnType;
     SimpleIdentifier nameNode = function.name;
     String name = nameNode.name;
     FunctionExpression functionExpression = function.functionExpression;
     FormalParameterList parameters = functionExpression.parameters;
     ElementKind kind;
     if (function.isGetter) {
       kind = ElementKind.GETTER;
     } else if (function.isSetter) {
       kind = ElementKind.SETTER;
     } else {
       kind = ElementKind.FUNCTION;
     }
-    _SourceRegion sourceRegion = _getSourceRegion(function);
+    SourceRange range = _getSourceRange(function);
     String parametersStr = _safeToSource(parameters);
     String returnTypeStr = _safeToSource(returnType);
     Element element = new Element(
         kind,
         name,
         Element.makeFlags(
             isPrivate: Identifier.isPrivateName(name),
             isDeprecated: _isDeprecated(function),
             isStatic: isStatic),
         location: _getLocationNode(nameNode),
         parameters: parametersStr,
         returnType: returnTypeStr);
     List<Outline> contents = _addLocalFunctionOutlines(functionExpression.body);
-    Outline outline = new Outline(
-        element, sourceRegion.offset, sourceRegion.length,
+    Outline outline = new Outline(element, range.offset, range.length,
         children: nullIfEmpty(contents));
     return outline;
   }
 
   Outline _newFunctionTypeAliasOutline(FunctionTypeAlias node) {
     TypeAnnotation returnType = node.returnType;
     SimpleIdentifier nameNode = node.name;
     String name = nameNode.name;
-    _SourceRegion sourceRegion = _getSourceRegion(node);
+    SourceRange range = _getSourceRange(node);
     FormalParameterList parameters = node.parameters;
     String parametersStr = _safeToSource(parameters);
     String returnTypeStr = _safeToSource(returnType);
     Element element = new Element(
         ElementKind.FUNCTION_TYPE_ALIAS,
         name,
         Element.makeFlags(
             isPrivate: Identifier.isPrivateName(name),
             isDeprecated: _isDeprecated(node)),
         location: _getLocationNode(nameNode),
         parameters: parametersStr,
         returnType: returnTypeStr,
         typeParameters: _getTypeParametersStr(node.typeParameters));
-    return new Outline(element, sourceRegion.offset, sourceRegion.length);
+    return new Outline(element, range.offset, range.length);
   }
 
   Outline _newMethodOutline(MethodDeclaration method) {
     TypeAnnotation returnType = method.returnType;
     SimpleIdentifier nameNode = method.name;
     String name = nameNode.name;
     FormalParameterList parameters = method.parameters;
     ElementKind kind;
     if (method.isGetter) {
       kind = ElementKind.GETTER;
     } else if (method.isSetter) {
       kind = ElementKind.SETTER;
     } else {
       kind = ElementKind.METHOD;
     }
-    _SourceRegion sourceRegion = _getSourceRegion(method);
+    SourceRange range = _getSourceRange(method);
     String parametersStr = parameters?.toSource();
     String returnTypeStr = _safeToSource(returnType);
     Element element = new Element(
         kind,
         name,
         Element.makeFlags(
             isPrivate: Identifier.isPrivateName(name),
             isDeprecated: _isDeprecated(method),
             isAbstract: method.isAbstract,
             isStatic: method.isStatic),
         location: _getLocationNode(nameNode),
         parameters: parametersStr,
         returnType: returnTypeStr);
     List<Outline> contents = _addLocalFunctionOutlines(method.body);
-    Outline outline = new Outline(
-        element, sourceRegion.offset, sourceRegion.length,
+    Outline outline = new Outline(element, range.offset, range.length,
         children: nullIfEmpty(contents));
     return outline;
   }
 
   Outline _newUnitOutline(List<Outline> unitContents) {
     Element element = new Element(
         ElementKind.COMPILATION_UNIT, '<unit>', Element.makeFlags(),
         location: _getLocationNode(unit));
     return new Outline(element, unit.offset, unit.length,
         children: nullIfEmpty(unitContents));
   }
 
   Outline _newVariableOutline(String typeName, ElementKind kind,
       VariableDeclaration variable, bool isStatic) {
     SimpleIdentifier nameNode = variable.name;
     String name = nameNode.name;
-    _SourceRegion sourceRegion = _getSourceRegion(variable);
+    SourceRange range = _getSourceRange(variable);
     Element element = new Element(
         kind,
         name,
         Element.makeFlags(
             isPrivate: Identifier.isPrivateName(name),
             isDeprecated: _isDeprecated(variable),
             isStatic: isStatic,
             isConst: variable.isConst,
             isFinal: variable.isFinal),
         location: _getLocationNode(nameNode),
         returnType: typeName);
-    Outline outline =
-        new Outline(element, sourceRegion.offset, sourceRegion.length);
+    Outline outline = new Outline(element, range.offset, range.length);
     return outline;
   }
 
   static String _getTypeParametersStr(TypeParameterList parameters) {
     if (parameters == null) {
       return null;
     }
     return parameters.toSource();
   }
 
@@ skipping 16 matching lines @@
   final DartUnitOutlineComputer outlineComputer;
   final List<Outline> contents;
 
   _LocalFunctionOutlinesVisitor(this.outlineComputer, this.contents);
 
   @override
   visitFunctionDeclaration(FunctionDeclaration node) {
     contents.add(outlineComputer._newFunctionOutline(node, false));
   }
 }
-
-/**
- * A range of characters.
- */
-class _SourceRegion {
-  final int length;
-  final int offset;
-  _SourceRegion(this.offset, this.length);
-}