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Viewing changes to external/nrefactory/ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/RedundantNullCheckIssue.cs

  • Committer: Package Import Robot
  • Author(s): Jo Shields
  • Date: 2013-05-12 09:46:03 UTC
  • mto: This revision was merged to the branch mainline in revision 29.
  • Revision ID: package-import@ubuntu.com-20130512094603-mad323bzcxvmcam0
Tags: upstream-4.0.5+dfsg
Import upstream version 4.0.5+dfsg

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external/nrefactory/ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/RedundantNullCheckIssue.cs
 
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//
 
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// RedundantNullCheckIssue.cs
 
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//
 
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// Author:
 
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//         Ji Kun <jikun.nus@gmail.com>
 
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//
 
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// Copyright (c) 2013 Ji Kun
 
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//
 
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// Permission is hereby granted, free of charge, to any person obtaining a copy
 
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// of this software and associated documentation files (the "Software"), to deal
 
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// in the Software without restriction, including without limitation the rights
 
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 
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// copies of the Software, and to permit persons to whom the Software is
 
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// furnished to do so, subject to the following conditions:
 
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//
 
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// The above copyright notice and this permission notice shall be included in
 
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// all copies or substantial portions of the Software.
 
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//
 
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 
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// THE SOFTWARE.using System;
 
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using System.Collections.Generic;
 
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using ICSharpCode.NRefactory.PatternMatching;
 
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using ICSharpCode.NRefactory.TypeSystem;
 
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using ICSharpCode.NRefactory.CSharp.Resolver;
 
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using ICSharpCode.NRefactory.Semantics;
 
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using System.Linq;
 
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using ICSharpCode.NRefactory.TypeSystem.Implementation;
 
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namespace ICSharpCode.NRefactory.CSharp.Refactoring
 
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{
 
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        [IssueDescription("Redundant null check",
 
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                                          Description = "When 'is' keyword is used, which implicitly check null.",
 
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                                          Category = IssueCategories.Redundancies,
 
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                                          Severity = Severity.Suggestion,
 
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                          ResharperDisableKeyword = "RedundantNullCheck",
 
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                                          IssueMarker = IssueMarker.GrayOut)]
 
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        public class RedundantNullCheckIssue : ICodeIssueProvider
 
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        {
 
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                private static readonly Pattern pattern1
 
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                        = new Choice {
 
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                        //  x is Record && x!= null      
 
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                        new BinaryOperatorExpression(
 
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                                new IsExpression
 
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                                        {
 
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                                                Expression = new AnyNode("a"),
 
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                                                Type = new AnyNode("t")
 
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                                        }, BinaryOperatorType.ConditionalAnd,
 
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                                PatternHelper.CommutativeOperator(new Backreference("a"),
 
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                                                                                                        BinaryOperatorType.
 
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                                                                                                                InEquality,
 
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                                                                                                        new NullReferenceExpression
 
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                                                                                                                ())
 
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                                )
 
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                };
 
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                private static readonly Pattern pattern2
 
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                   = new Choice {
 
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                        //  x != null && x is Record
 
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                        new BinaryOperatorExpression (
 
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                                PatternHelper.CommutativeOperator (new AnyNode("a"), 
 
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                                                                                                                BinaryOperatorType.InEquality, 
 
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                                                                                                        new NullReferenceExpression())                  
 
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                                , BinaryOperatorType.ConditionalAnd,
 
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                                new IsExpression {
 
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                                        Expression = new Backreference("a"),
 
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                                        Type = new AnyNode("t")
 
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                                }
 
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                        )       
 
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                };
 
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                public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
 
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                {
 
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                        return new GatherVisitor(context).GetIssues();
 
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                }
 
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                class GatherVisitor : GatherVisitorBase<RedundantNullCheckIssue>
 
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                {
 
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                        public GatherVisitor(BaseRefactoringContext ctx)
 
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                                : base(ctx)
 
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                        {
 
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                        }
 
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                        public override void VisitBinaryOperatorExpression(BinaryOperatorExpression binaryOperatorExpression)
 
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                        {
 
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                                base.VisitBinaryOperatorExpression(binaryOperatorExpression);
 
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                                Match m1 = pattern1.Match(binaryOperatorExpression);
 
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                                if (m1.Success) {
 
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                                        AddIssue(binaryOperatorExpression, ctx.TranslateString("Remove redundant IsNULL check"), script => {
 
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                                                Expression expr = binaryOperatorExpression.Left;
 
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                                                script.Replace(binaryOperatorExpression, expr);
 
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                                        });
 
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                                        return;
 
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                                }
 
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                                Match m2 = pattern2.Match(binaryOperatorExpression);
 
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                                if (m2.Success) {
 
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                                        AddIssue(binaryOperatorExpression, ctx.TranslateString("Remove redundant IsNULL check"), script => {
 
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                                                Expression expr = binaryOperatorExpression.Right;
 
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                                                script.Replace(binaryOperatorExpression, expr);
 
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                                        });
 
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                                        return;
 
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                                }
 
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                        }
 
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                }
 
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        }
 
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}
 
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