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//
// ConvertForeachToFor.cs
//
// Author:
// Mike Krüger <mkrueger@novell.com>
//
// Copyright (c) 2011 Mike Krüger <mkrueger@novell.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
using System;
using System.Linq;
using ICSharpCode.NRefactory.TypeSystem;
using System.Threading;
using System.Collections.Generic;
namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
/// <summary>
/// Converts a foreach loop to for.
/// </summary>
[ContextAction("Convert 'foreach' loop to 'for'", Description = "Works on 'foreach' loops that allow direct access to its elements.")]
public class ConvertForeachToForAction : ICodeActionProvider
{
static string[] VariableNames = new string[] { "i", "j", "k", "l", "n", "m", "x", "y", "z"};
static string[] CollectionNames = new string[] { "list" };
static string GetName(ICSharpCode.NRefactory.CSharp.Resolver.CSharpResolver state, string[] variableNames)
{
for (int i = 0; i < 1000; i++) {
foreach (var vn in variableNames) {
string id = i > 0 ? vn + i : vn;
var rr = state.LookupSimpleNameOrTypeName(id, new IType[0], NameLookupMode.Expression);
if (rr.IsError)
return id;
}
}
return null;
}
public IEnumerable<CodeAction> GetActions(RefactoringContext context)
{
var foreachStatement = GetForeachStatement(context);
if (foreachStatement == null) {
yield break;
}
var state = context.GetResolverStateBefore (foreachStatement.EmbeddedStatement);
string name = GetName(state, VariableNames);
if (name == null) // very unlikely, but just in case ...
yield break;
yield return new CodeAction(context.TranslateString("Convert 'foreach' loop to 'for'"), script => {
var result = context.Resolve(foreachStatement.InExpression);
var countProperty = GetCountProperty(result.Type);
// TODO: use another variable name if 'i' is already in use
var initializer = new VariableDeclarationStatement(new PrimitiveType("int"), name, new PrimitiveExpression(0));
var id1 = new IdentifierExpression(name);
var id2 = id1.Clone();
var id3 = id1.Clone();
var inExpression = foreachStatement.InExpression;
Statement declarationStatement = null;
if (inExpression is ObjectCreateExpression || inExpression is ArrayCreateExpression) {
string listName = GetName(state, CollectionNames) ?? "col";
declarationStatement = new VariableDeclarationStatement (
new PrimitiveType ("var"),
listName,
inExpression.Clone ()
);
inExpression = new IdentifierExpression (listName);
}
var variableDeclarationStatement = new VariableDeclarationStatement(
foreachStatement.VariableType.Clone(),
foreachStatement.VariableName,
new IndexerExpression(inExpression.Clone(), id3)
);
var forStatement = new ForStatement() {
Initializers = { initializer },
Condition = new BinaryOperatorExpression (id1, BinaryOperatorType.LessThan, new MemberReferenceExpression (inExpression.Clone (), countProperty)),
Iterators = { new ExpressionStatement (new UnaryOperatorExpression (UnaryOperatorType.PostIncrement, id2)) },
EmbeddedStatement = new BlockStatement {
variableDeclarationStatement
}
};
if (foreachStatement.EmbeddedStatement is BlockStatement) {
variableDeclarationStatement.Remove();
var oldBlock = (BlockStatement)foreachStatement.EmbeddedStatement.Clone();
if (oldBlock.Statements.Any()) {
oldBlock.Statements.InsertBefore(oldBlock.Statements.First(), variableDeclarationStatement);
} else {
oldBlock.Statements.Add(variableDeclarationStatement);
}
forStatement.EmbeddedStatement = oldBlock;
} else {
forStatement.EmbeddedStatement.AddChild (foreachStatement.EmbeddedStatement.Clone (), BlockStatement.StatementRole);
}
if (declarationStatement != null)
script.InsertBefore (foreachStatement, declarationStatement);
script.Replace (foreachStatement, forStatement);
script.Link (initializer.Variables.First ().NameToken, id1, id2, id3);
}, foreachStatement);
}
static string GetCountProperty(IType type)
{
if (type.Kind == TypeKind.Array) {
return "Length";
}
return "Count";
}
static ForeachStatement GetForeachStatement (RefactoringContext context)
{
var astNode = context.GetNode ();
if (astNode == null)
return null;
var result = (astNode as ForeachStatement) ?? astNode.Parent as ForeachStatement;
if (result == null)
return null;
var collection = context.Resolve (result.InExpression);
if (collection.Type.Kind != TypeKind.Array && !collection.Type.GetProperties(p => p.IsIndexer).Any())
return null;
return result;
}
}
}
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