FileCodeFix

Author: inyutin-maxim

System.IO.Abstractions.Analyzers/Analyzers/FileServiceInterfaceInjectionAnalyzer.cs

@@ -17,7 +17,7 @@ public class FileServiceInterfaceInjectionAnalyzer : BaseFileSystemAnalyzer
 		/// Diagnostic Identifier
 		/// </summary>
 		[UsedImplicitly]
-		public const string DiagnosticId = "IO0001";
+		public const string DiagnosticId = Constants.Io0001;
 
 		/// <summary>
 		/// Diagnostic Title
@@ -61,8 +61,9 @@ protected override void AnalyzeCompilation(CompilationStartAnalysisContext compi
 						return;
 					}
 
-					var fileSystem = classDeclarationSyntax.Members.OfType<FieldDeclarationSyntax>().FirstOrDefault(x =>
-						x.NormalizeWhitespace().ToFullString() == fileSystemContext.FileSystemType.Name);
+					var fileSystem = classDeclarationSyntax.Members.OfType<FieldDeclarationSyntax>()
+						.FirstOrDefault(x =>
+							x.NormalizeWhitespace().ToFullString() == fileSystemContext.FileSystemType.Name);
 
 					if (fileSystem == null)
 					{

System.IO.Abstractions.Analyzers/Analyzers/FileSystemTypeAnalyzers/FileAnalyzer.cs

@@ -13,7 +13,7 @@ public class FileAnalyzer : BaseFileSystemNodeAnalyzer
 		/// Diagnostic Identifier
 		/// </summary>
 		[UsedImplicitly]
-		public const string DiagnosticId = "IO0002";
+		public const string DiagnosticId = Constants.Io0002;
 
 		/// <summary>
 		/// Diagnostic Title

System.IO.Abstractions.Analyzers/CodeActions/FileSystemInvokeCodeAction.cs

@@ -0,0 +1,39 @@
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CodeActions;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Editing;
+using SF = Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
+
+namespace System.IO.Abstractions.Analyzers.CodeActions
+{
+	public class FileSystemInvokeCodeAction : CodeAction
+	{
+		private const string FieldFileSystemName = "_fileSystem";
+
+		private readonly Document _document;
+
+		private readonly InvocationExpressionSyntax _invocation;
+
+		public override string Title { get; }
+
+		public override string EquivalenceKey => Title;
+
+		public FileSystemInvokeCodeAction(string title, Document document, InvocationExpressionSyntax invocation)
+		{
+			Title = title;
+			_document = document;
+			_invocation = invocation;
+		}
+
+		protected override async Task<Document> GetChangedDocumentAsync(CancellationToken cancellationToken)
+		{
+			var editor = await DocumentEditor.CreateAsync(_document, cancellationToken).ConfigureAwait(false);
+
+			editor.ReplaceNode(_invocation, SF.ParseExpression($"{FieldFileSystemName}.{_invocation.NormalizeWhitespace().ToFullString()}"));
+
+			return editor.GetChangedDocument();
+		}
+	}
+}

System.IO.Abstractions.Analyzers/CodeFixes/FileCodeFix.cs

@@ -0,0 +1,32 @@
+using System.Collections.Immutable;
+using System.Composition;
+using System.IO.Abstractions.Analyzers.CodeActions;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CodeFixes;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace System.IO.Abstractions.Analyzers.CodeFixes
+{
+	[Shared]
+	[ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(FileCodeFix))]
+	public class FileCodeFix : CodeFixProvider
+	{
+		private const string Title = "Use IFileSystem.File for improved testablity";
+
+		public override ImmutableArray<string> FixableDiagnosticIds => ImmutableArray.Create(Constants.Io0002);
+
+		public sealed override FixAllProvider GetFixAllProvider() => WellKnownFixAllProviders.BatchFixer;
+
+		public sealed override async Task RegisterCodeFixesAsync(CodeFixContext context)
+		{
+			var root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
+			var invocation = root.FindNode(context.Span).FirstAncestorOrSelf<InvocationExpressionSyntax>();
+
+			context.RegisterCodeFix(new FileSystemInvokeCodeAction(Title,
+					context.Document,
+					invocation),
+				context.Diagnostics);
+		}
+	}
+}

System.IO.Abstractions.Analyzers/CodeFixes/FileServiceInterfaceInjectionCodeFix.cs

@@ -16,7 +16,7 @@ public class FileServiceInterfaceInjectionCodeFix : CodeFixProvider
 		private const string Title = "Use System.IO.Abstractions";
 
 		public sealed override ImmutableArray<string> FixableDiagnosticIds =>
-			ImmutableArray.Create(FileServiceInterfaceInjectionAnalyzer.DiagnosticId);
+			ImmutableArray.Create(Constants.Io0001);
 
 		public sealed override FixAllProvider GetFixAllProvider() => WellKnownFixAllProviders.BatchFixer;
 

System.IO.Abstractions.Analyzers/Constants.cs

@@ -2,9 +2,14 @@ namespace System.IO.Abstractions.Analyzers
 {
 	public static class Constants
 	{
-        internal const string FileSystem = "System.IO.Abstractions.IFileSystem";
-        internal const string FileSystemName = "IFileSystem";
+		internal const string FileSystem = "System.IO.Abstractions.IFileSystem";
 
-        internal const string FileSystemNameSpace = "System.IO.Abstractions";
+		internal const string FileSystemName = "IFileSystem";
+
+		internal const string FileSystemNameSpace = "System.IO.Abstractions";
+
+		public const string Io0001 = "IO0001";
+
+		public const string Io0002 = "IO0002";
 	}
 }