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//
// SimplifyIfFlowAction.cs
//
// Author:
// Ciprian Khlud <ciprian.mustiata@yahoo.com>
//
// Copyright (c) 2013 Ciprian Khlud <ciprian.mustiata@yahoo.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.Collections.Generic;
namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
[ContextAction("Simplify if flow", Description = "Inverts if and reduces branching ")]
public class SimplifyIfFlowAction : ICodeActionProvider
{
readonly InsertParenthesesVisitor _insertParenthesesVisitor = new InsertParenthesesVisitor();
public IEnumerable<CodeAction> GetActions(RefactoringContext context)
{
// TODO: Invert if without else
// ex. if (cond) DoSomething () == if (!cond) return; DoSomething ()
// beware of loop contexts return should be continue then.
var ifStatement = GetIfElseStatement(context);
if (ifStatement == null)
yield break;
yield return new CodeAction(context.TranslateString("Invert if"), script =>
{
GenerateNewScript(script, ifStatement);
}, ifStatement);
}
internal static void InsertBody(Script script, IfElseStatement ifStatement)
{
var ifBody = ifStatement.TrueStatement.Clone();
if (ifBody is BlockStatement) {
AstNode last = ifStatement;
foreach (var stmt in ((BlockStatement)ifBody).Children) {
if (stmt.Role == Roles.LBrace || stmt.Role == Roles.RBrace || stmt.Role == Roles.NewLine)
continue;
script.InsertAfter(last, stmt);
last = stmt;
}
} else {
script.InsertAfter(ifStatement, ifBody);
}
script.FormatText(ifStatement.Parent);
}
void GenerateNewScript(Script script, IfElseStatement ifStatement)
{
var mergedIfStatement = new IfElseStatement {
Condition = CSharpUtil.InvertCondition(ifStatement.Condition),
TrueStatement = new ReturnStatement()
};
mergedIfStatement.Condition.AcceptVisitor(_insertParenthesesVisitor);
script.Replace(ifStatement, mergedIfStatement);
InsertBody(script, ifStatement);
}
static IfElseStatement GetIfElseStatement(RefactoringContext context)
{
var result = context.GetNode<IfElseStatement>();
if (result == null)
return null;
if (!(result.IfToken.Contains(context.Location)
&& !result.TrueStatement.IsNull
&& result.FalseStatement.IsNull))
return null;
if (!(result.Parent is BlockStatement) || !(result.Parent.Parent is MethodDeclaration))
return null;
var parentMethod = (MethodDeclaration)result.Parent.Parent;
if (parentMethod.ReturnType.ToString() != "void")
return null;
var nextSibling = result.GetNextSibling(n => n is Statement);
if (nextSibling == null)
return result;
nextSibling = nextSibling.GetNextSibling (n => n is Statement);
if (nextSibling != null)
return null;
return result;
}
}
}
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