之前写过两篇关于Roslyn源生成器生成源代码的用例,今天使用Roslyn的代码修复器CodeFixProvider实现一个cs文件头部注释的功能,
代码修复器会同时涉及到CodeFixProvider和DiagnosticAnalyzer,
实现FileHeaderAnalyzer
首先我们知道修复器的先决条件是分析器,比如这里,如果要对代码添加头部注释,那么分析器必须要给出对应的分析提醒:
我们首先实现实现名为FileHeaderAnalyzer的分析器:
[DiagnosticAnalyzer(LanguageNames.CSharp)]
public class FileHeaderAnalyzer : DiagnosticAnalyzer
{public const string DiagnosticId = "GEN050";private static readonly LocalizableString Title = "文件缺少头部信息";private static readonly LocalizableString MessageFormat = "文件缺少头部信息";private static readonly LocalizableString Description = "每个文件应包含头部信息.";private const string Category = "Document";private static readonly DiagnosticDescriptor Rule = new(DiagnosticId, Title, MessageFormat, Category, DiagnosticSeverity.Warning, isEnabledByDefault: true, description: Description);public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => [Rule];public override void Initialize(AnalysisContext context){if (context is null)return;context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);context.EnableConcurrentExecution();context.RegisterSyntaxTreeAction(AnalyzeSyntaxTree);}private static void AnalyzeSyntaxTree(SyntaxTreeAnalysisContext context){var root = context.Tree.GetRoot(context.CancellationToken);var firstToken = root.GetFirstToken();// 检查文件是否以注释开头var hasHeaderComment = firstToken.LeadingTrivia.Any(trivia => trivia.IsKind(SyntaxKind.SingleLineCommentTrivia) || trivia.IsKind(SyntaxKind.MultiLineCommentTrivia));if (!hasHeaderComment){var diagnostic = Diagnostic.Create(Rule, Location.Create(context.Tree, TextSpan.FromBounds(0, 0)));context.ReportDiagnostic(diagnostic);}}
}
FileHeaderAnalyzer分析器的原理很简单,需要重载几个方法,重点是Initialize方法,这里的RegisterSyntaxTreeAction即核心代码,SyntaxTreeAnalysisContext对象取到当前源代码的SyntaxNode根节点,然后判断TA的第一个SyntaxToken是否为注释行(SyntaxKind.SingleLineCommentTrivia|SyntaxKind.MultiLineCommentTrivia)
如果不为注释行,那么就通知分析器!
实现了上面的代码我们看一下效果:
并且编译的时候分析器将会在错误面板中显示警告清单:
实现CodeFixProvider
分析器完成了,现在我们就来实现名为AddFileHeaderCodeFixProvider的修复器,
/// <summary>
/// 自动给文件添加头部注释
/// </summary>
[ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(AddFileHeaderCodeFixProvider))]
[Shared]
public class AddFileHeaderCodeFixProvider : CodeFixProvider
{private const string Title = "添加文件头部信息";//约定模板文件的名称private const string ConfigFileName = "Biwen.AutoClassGen.Comment";private const string VarPrefix = "$";//变量前缀//如果模板不存在的时候的默认注释文本private const string DefaultComment = """// Licensed to the {Product} under one or more agreements.// The {Product} licenses this file to you under the MIT license.// See the LICENSE file in the project root for more information.""";#region regexprivate const RegexOptions ROptions = RegexOptions.Compiled | RegexOptions.Singleline;private static readonly Regex VersionRegex = new(@"<Version>(.*?)</Version>", ROptions);private static readonly Regex CopyrightRegex = new(@"<Copyright>(.*?)</Copyright>", ROptions);private static readonly Regex CompanyRegex = new(@"<Company>(.*?)</Company>", ROptions);private static readonly Regex DescriptionRegex = new(@"<Description>(.*?)</Description>", ROptions);private static readonly Regex AuthorsRegex = new(@"<Authors>(.*?)</Authors>", ROptions);private static readonly Regex ProductRegex = new(@"<Product>(.*?)</Product>", ROptions);private static readonly Regex TargetFrameworkRegex = new(@"<TargetFramework>(.*?)</TargetFramework>", ROptions);private static readonly Regex TargetFrameworksRegex = new(@"<TargetFrameworks>(.*?)</TargetFrameworks>", ROptions);private static readonly Regex ImportRegex = new(@"<Import Project=""(.*?)""", ROptions);#endregionpublic sealed override ImmutableArray<string> FixableDiagnosticIds{//重写FixableDiagnosticIds,返回分析器的报告Id,表示当前修复器能修复的对应Idget { return [FileHeaderAnalyzer.DiagnosticId]; }}public sealed override FixAllProvider GetFixAllProvider(){return WellKnownFixAllProviders.BatchFixer;}public override Task RegisterCodeFixesAsync(CodeFixContext context){var diagnostic = context.Diagnostics[0];var diagnosticSpan = diagnostic.Location.SourceSpan;context.RegisterCodeFix(CodeAction.Create(title: Title,createChangedDocument: c => FixDocumentAsync(context.Document, diagnosticSpan, c),equivalenceKey: Title),diagnostic);return Task.CompletedTask;}private static async Task<Document> FixDocumentAsync(Document document, TextSpan span, CancellationToken ct){var root = await document.GetSyntaxRootAsync(ct).ConfigureAwait(false);//从项目配置中获取文件头部信息var projFilePath = document.Project.FilePath ?? "C:\\test.csproj";//单元测试时没有文件路径,因此使用默认路径var projectDirectory = Path.GetDirectoryName(projFilePath);var configFilePath = Path.Combine(projectDirectory, ConfigFileName);var comment = DefaultComment;string? copyright = "MIT";string? author = Environment.UserName;string? company = string.Empty;string? description = string.Empty;string? title = document.Project.Name;string? version = document.Project.Version.ToString();string? product = document.Project.AssemblyName;string? file = Path.GetFileName(document.FilePath);string? targetFramework = string.Empty;
#pragma warning disable CA1305 // 指定 IFormatProviderstring? date = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
#pragma warning restore CA1305 // 指定 IFormatProviderif (File.Exists(configFilePath)){comment = File.ReadAllText(configFilePath, System.Text.Encoding.UTF8);}#region 查找程序集元数据// 加载项目文件:var text = File.ReadAllText(projFilePath, System.Text.Encoding.UTF8);// 载入Import的文件,例如 : <Import Project="..\Version.props" />// 使用正则表达式匹配Project:var importMatchs = ImportRegex.Matches(text);foreach (Match importMatch in importMatchs){var importFile = Path.Combine(projectDirectory, importMatch.Groups[1].Value);if (File.Exists(importFile)){text += File.ReadAllText(importFile);}}//存在变量引用的情况,需要解析string RawVal(string old, string @default){if (old == null)return @default;//当取得的版本号为变量引用:$(Version)的时候,需要再次解析if (version.StartsWith(VarPrefix, StringComparison.Ordinal)){var varName = old.Substring(2, old.Length - 3);var varMatch = new Regex($@"<{varName}>(.*?)</{varName}>", RegexOptions.Singleline).Match(text);if (varMatch.Success){return varMatch.Groups[1].Value;}//未找到变量引用,返回默return @default;}return old;}var versionMatch = VersionRegex.Match(text);var copyrightMath = CopyrightRegex.Match(text);var companyMatch = CompanyRegex.Match(text);var descriptionMatch = DescriptionRegex.Match(text);var authorsMatch = AuthorsRegex.Match(text);var productMatch = ProductRegex.Match(text);var targetFrameworkMatch = TargetFrameworkRegex.Match(text);var targetFrameworksMatch = TargetFrameworksRegex.Match(text);if (versionMatch.Success){version = RawVal(versionMatch.Groups[1].Value, version);}if (copyrightMath.Success){copyright = RawVal(copyrightMath.Groups[1].Value, copyright);}if (companyMatch.Success){company = RawVal(companyMatch.Groups[1].Value, company);}if (descriptionMatch.Success){description = RawVal(descriptionMatch.Groups[1].Value, description);}if (authorsMatch.Success){author = RawVal(authorsMatch.Groups[1].Value, author);}if (productMatch.Success){product = RawVal(productMatch.Groups[1].Value, product);}if (targetFrameworkMatch.Success){targetFramework = RawVal(targetFrameworkMatch.Groups[1].Value, targetFramework);}if (targetFrameworksMatch.Success){targetFramework = RawVal(targetFrameworksMatch.Groups[1].Value, targetFramework);}#endregion//使用正则表达式替换comment = Regex.Replace(comment, @"\{(?<key>[^}]+)\}", m =>{var key = m.Groups["key"].Value;return key switch{"Product" => product,"Title" => title,"Version" => version,"Date" => date,"Author" => author,"Company" => company,"Copyright" => copyright,"File" => file,"Description" => description,"TargetFramework" => targetFramework,_ => m.Value,};}, RegexOptions.Singleline);var headerComment = SyntaxFactory.Comment(comment + Environment.NewLine);var newRoot = root?.WithLeadingTrivia(headerComment);if (newRoot == null){return document;}var newDocument = document.WithSyntaxRoot(newRoot);return newDocument;}
}代码修复器最重要的重载方法RegisterCodeFixesAsync,对象CodeFixContext包含项目和源代码以及对应分析器的信息:
比如:CodeFixContext.Document表示对应的源代码,CodeFixContext.Document.Project表示对应项目,CodeFixContext.Document.Project.FilePath就是代码中我需要的*.csproj的项目文件,
我们取到项目文件,那么我们就可以读取配置在项目文件中的信息,比如Company,Authors,Description,甚至上一篇我们提到的版本号等有用信息,当前我用的正则表达式,当然如果可以你也可以使用XPath,
然后取到的有用数据替换模板即可得到想要的注释代码片段了!
比如我的Comment模板文件Biwen.AutoClassGen.Comment
// Licensed to the {Product} under one or more agreements.
// The {Product} licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
// {Product} Author: 万雅虎 Github: https://github.com/vipwan
// {Description}
// Modify Date: {Date} {File}
替换后将会生成如下的代码:
// Licensed to the Biwen.QuickApi under one or more agreements.
// The Biwen.QuickApi licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
// Biwen.QuickApi Author: 万雅虎 Github: https://github.com/vipwan
// Biwen.QuickApi ,NET9+ MinimalApi CQRS
// Modify Date: 2024-09-07 15:22:42 Verb.cs
最后使用SyntaxFactory.Comment(comment)方法生成一个注释的SyntaxTrivia并附加到当前的根语法树上,最后返回这个新的Document即可!
大功告成,我们来看效果:
以上代码就完成了整个源生成步骤,最后你可以使用我发布的nuget包体验:
dotnet add package Biwen.AutoClassGen
源代码我发布到了GitHub,欢迎star! https://github.com/vipwan/Biwen.AutoClassGen
https://github.com/vipwan/Biwen.AutoClassGen/blob/master/Biwen.AutoClassGen.Gen/CodeFixProviders/AddFileHeaderCodeFixProvider.cs
