// // UnreachableCodeIssue.cs // // Author: // Mansheng Yang // // Copyright (c) 2012 Mansheng Yang // // 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.Collections.Generic; using ICSharpCode.NRefactory.CSharp.Analysis; namespace ICSharpCode.NRefactory.CSharp.Refactoring { [IssueDescription ("Code is unreachable", Description = "Code is unreachable.", Category = IssueCategories.Redundancies, Severity = Severity.Warning, IssueMarker = IssueMarker.GrayOut)] public class UnreachableCodeIssue : ICodeIssueProvider { public IEnumerable GetIssues (BaseRefactoringContext context) { return new GatherVisitor (context).GetIssues (); } class GatherVisitor : GatherVisitorBase { HashSet unreachableNodes; public GatherVisitor (BaseRefactoringContext ctx) : base (ctx) { unreachableNodes = new HashSet (); } public override void VisitMethodDeclaration (MethodDeclaration methodDeclaration) { StatementIssueCollector.Collect (this, methodDeclaration.Body); base.VisitMethodDeclaration (methodDeclaration); } public override void VisitLambdaExpression (LambdaExpression lambdaExpression) { var blockStatement = lambdaExpression.Body as BlockStatement; if (blockStatement != null) StatementIssueCollector.Collect (this, blockStatement); base.VisitLambdaExpression (lambdaExpression); } public override void VisitAnonymousMethodExpression (AnonymousMethodExpression anonymousMethodExpression) { StatementIssueCollector.Collect (this, anonymousMethodExpression.Body); base.VisitAnonymousMethodExpression (anonymousMethodExpression); } public override void VisitConditionalExpression (ConditionalExpression conditionalExpression) { var resolveResult = ctx.Resolve (conditionalExpression.Condition); if (resolveResult.ConstantValue is bool) { var condition = (bool)resolveResult.ConstantValue; Expression resultExpr, unreachableExpr; if (condition) { resultExpr = conditionalExpression.TrueExpression; unreachableExpr = conditionalExpression.FalseExpression; } else { resultExpr = conditionalExpression.FalseExpression; unreachableExpr = conditionalExpression.TrueExpression; } unreachableNodes.Add (unreachableExpr); AddIssue (unreachableExpr, ctx.TranslateString ("Remove unreachable code"), script => script.Replace (conditionalExpression, resultExpr.Clone ())); } base.VisitConditionalExpression (conditionalExpression); } protected override void VisitChildren (AstNode node) { // skip unreachable nodes if (!unreachableNodes.Contains (node)) base.VisitChildren (node); } class StatementIssueCollector : DepthFirstAstVisitor { GatherVisitor visitor; ReachabilityAnalysis reachability; HashSet collectedStatements; private StatementIssueCollector (GatherVisitor visitor, ReachabilityAnalysis reachability) { collectedStatements = new HashSet (); this.visitor = visitor; this.reachability = reachability; } public static void Collect (GatherVisitor visitor, BlockStatement body) { var reachability = visitor.ctx.CreateReachabilityAnalysis (body); var collector = new StatementIssueCollector (visitor, reachability); collector.VisitBlockStatement (body); } protected override void VisitChildren (AstNode node) { var statement = node as Statement; if (statement == null || !AddStatement (statement)) base.VisitChildren (node); } bool AddStatement(Statement statement) { if (reachability.IsReachable (statement)) return false; if (collectedStatements.Contains (statement)) return true; var prevEnd = statement.GetPrevNode ().EndLocation; // group multiple continuous statements into one issue var start = statement.StartLocation; collectedStatements.Add (statement); visitor.unreachableNodes.Add (statement); while (statement.NextSibling is Statement) { statement = (Statement)statement.NextSibling; collectedStatements.Add (statement); visitor.unreachableNodes.Add (statement); } var end = statement.EndLocation; var removeAction = new CodeAction (visitor.ctx.TranslateString ("Remove unreachable code"), script => { var startOffset = script.GetCurrentOffset (prevEnd); var endOffset = script.GetCurrentOffset (end); script.RemoveText (startOffset, endOffset - startOffset); }); var commentAction = new CodeAction (visitor.ctx.TranslateString ("Comment unreachable code"), script => { var startOffset = script.GetCurrentOffset (prevEnd); script.InsertText (startOffset, Environment.NewLine + "/*"); var endOffset = script.GetCurrentOffset (end); script.InsertText (endOffset, Environment.NewLine + "*/"); }); var actions = new [] { removeAction, commentAction }; visitor.AddIssue (start, end, visitor.ctx.TranslateString ("Code is unreachable"), actions); return true; } // skip lambda and anonymous method public override void VisitLambdaExpression (LambdaExpression lambdaExpression) { } public override void VisitAnonymousMethodExpression ( AnonymousMethodExpression anonymousMethodExpression) { } } } } }