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110 lines
4.4 KiB
110 lines
4.4 KiB
// |
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// StringIsNullOrEmptyInspector.cs |
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// |
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// Author: |
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// Mike Krüger <mkrueger@xamarin.com> |
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// |
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// Copyright (c) 2012 Xamarin <http://xamarin.com> |
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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. |
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using System; |
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using System.Collections.Generic; |
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using System.Linq; |
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using ICSharpCode.NRefactory.PatternMatching; |
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namespace ICSharpCode.NRefactory.CSharp.Refactoring |
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{ |
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/// <summary> |
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/// Checks for str == null && str == "" |
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/// Converts to: string.IsNullOrEmpty (str) |
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/// </summary> |
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[IssueDescription("Use string.IsNullOrEmpty", |
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Description = "Uses shorter string.IsNullOrEmpty call instead of a longer condition.", |
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Category = IssueCategories.Improvements, |
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Severity = Severity.Suggestion)] |
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public class StringIsNullOrEmptyIssue : ICodeIssueProvider |
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{ |
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static readonly Pattern pattern = new Choice { |
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// str == null || str == "" |
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new BinaryOperatorExpression ( |
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PatternHelper.CommutativeOperator(new AnyNode ("str"), BinaryOperatorType.Equality, new NullReferenceExpression ()), |
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BinaryOperatorType.ConditionalOr, |
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PatternHelper.CommutativeOperator(new Backreference ("str"), BinaryOperatorType.Equality, new PrimitiveExpression ("")) |
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), |
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// str == "" || str == null |
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new BinaryOperatorExpression ( |
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PatternHelper.CommutativeOperator(new AnyNode ("str"), BinaryOperatorType.Equality, new PrimitiveExpression ("")), |
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BinaryOperatorType.ConditionalOr, |
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PatternHelper.CommutativeOperator(new Backreference ("str"), BinaryOperatorType.Equality, new NullReferenceExpression ()) |
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), |
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}; |
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static readonly Pattern negPattern = new Choice { |
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// str != null && str != "" |
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new BinaryOperatorExpression ( |
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PatternHelper.CommutativeOperator(new AnyNode ("str"), BinaryOperatorType.InEquality, new NullReferenceExpression ()), |
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BinaryOperatorType.ConditionalAnd, |
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PatternHelper.CommutativeOperator(new Backreference ("str"), BinaryOperatorType.InEquality, new PrimitiveExpression ("")) |
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), |
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// str != "" && str != null |
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new BinaryOperatorExpression ( |
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PatternHelper.CommutativeOperator(new AnyNode ("str"), BinaryOperatorType.InEquality, new PrimitiveExpression ("")), |
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BinaryOperatorType.ConditionalAnd, |
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PatternHelper.CommutativeOperator(new Backreference ("str"), BinaryOperatorType.InEquality, new NullReferenceExpression ()) |
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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, this).GetIssues(); |
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} |
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class GatherVisitor : GatherVisitorBase |
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{ |
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readonly StringIsNullOrEmptyIssue inspector; |
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public GatherVisitor (BaseRefactoringContext ctx, StringIsNullOrEmptyIssue inspector) : base (ctx) |
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{ |
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this.inspector = inspector; |
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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 m = pattern.Match(binaryOperatorExpression); |
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bool isNegated = false; |
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if (!m.Success) { |
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m = negPattern.Match(binaryOperatorExpression); |
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isNegated = true; |
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} |
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if (m.Success) { |
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var str = m.Get<Expression>("str").Single(); |
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AddIssue(binaryOperatorExpression, ctx.TranslateString("Use string.IsNullOrEmpty"), script => { |
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Expression expr = new PrimitiveType ("string").Invoke("IsNullOrEmpty", str.Clone()); |
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if (isNegated) |
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expr = new UnaryOperatorExpression (UnaryOperatorType.Not, expr); |
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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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