Add source generator for repository-pattern code

Related to #48

src/WeihanLi.EntityFramework.SourceGenerator/EFRepositorySourceGenerator.cs

@@ -0,0 +1,83 @@
+using System.Collections.Immutable;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Microsoft.CodeAnalysis.Text;
+
+namespace WeihanLi.EntityFramework.SourceGenerator;
+
+[Generator]
+public class EFRepositorySourceGenerator : IIncrementalGenerator
+{
+    public void Initialize(IncrementalGeneratorInitializationContext context)
+    {
+        var additionalFiles = context.AdditionalTextsProvider
+            .Where(file => file.Path.EndsWith(".template"))
+            .Select((file, cancellationToken) => file.GetText(cancellationToken)?.ToString())
+            .Where(content => !string.IsNullOrEmpty(content));
+
+        var dbContextDeclarations = context.SyntaxProvider
+            .CreateSyntaxProvider(
+                predicate: static (s, _) => IsDbContextDeclaration(s),
+                transform: static (ctx, _) => GetDbContextDeclaration(ctx))
+            .Where(static m => m is not null);
+
+        var combined = dbContextDeclarations.Combine(additionalFiles.Collect());
+
+        context.RegisterSourceOutput(combined, (spc, source) =>
+        {
+            var (dbContextDeclaration, templates) = source;
+            var dbContextName = dbContextDeclaration!.Identifier.Text;
+            var repositoryNamespace = dbContextDeclaration!.Parent!.GetNamespace();
+            var generatedCode = GenerateRepositoryCode(dbContextName, repositoryNamespace, templates);
+            spc.AddSource($"{dbContextName}Repository.g.cs", SourceText.From(generatedCode, Encoding.UTF8));
+        });
+    }
+
+    private static bool IsDbContextDeclaration(SyntaxNode node)
+    {
+        return node is ClassDeclarationSyntax classDeclaration &&
+               classDeclaration.BaseList?.Types.Any(t => t.ToString().Contains("DbContext")) == true;
+    }
+
+    private static ClassDeclarationSyntax? GetDbContextDeclaration(GeneratorSyntaxContext context)
+    {
+        var classDeclaration = (ClassDeclarationSyntax)context.Node;
+        return classDeclaration;
+    }
+
+    private static string GenerateRepositoryCode(string dbContextName, string repositoryNamespace, ImmutableArray<string> templates)
+    {
+        var builder = new StringBuilder();
+        builder.AppendLine("using WeihanLi.EntityFramework;");
+        builder.AppendLine($"namespace {repositoryNamespace}");
+        builder.AppendLine("{");
+
+        foreach (var template in templates)
+        {
+            var code = template.Replace("{{DbContextName}}", dbContextName);
+            builder.AppendLine(code);
+        }
+
+        builder.AppendLine("}");
+        return builder.ToString();
+    }
+}
+
+internal static class SyntaxNodeExtensions
+{
+    public static string GetNamespace(this SyntaxNode node)
+    {
+        while (node != null)
+        {
+            if (node is NamespaceDeclarationSyntax namespaceDeclaration)
+            {
+                return namespaceDeclaration.Name.ToString();
+            }
+
+            node = node.Parent;
+        }
+
+        return string.Empty;
+    }
+}

src/WeihanLi.EntityFramework.SourceGenerator/WeihanLi.EntityFramework.SourceGenerator.csproj

@@ -0,0 +1,28 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <LangVersion>latest</LangVersion>
+    <OutputPath>bin\$(Configuration)\</OutputPath>
+    <AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
+    <AppendRuntimeIdentifierToOutputPath>false</AppendRuntimeIdentifierToOutputPath>
+    <IsPackable>true</IsPackable>
+    <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
+    <PackageId>WeihanLi.EntityFramework.SourceGenerator</PackageId>
+    <Title>WeihanLi.EntityFramework.SourceGenerator</Title>
+    <Description>Source generator for WeihanLi.EntityFramework</Description>
+    <Authors>WeihanLi</Authors>
+    <Company>WeihanLi</Company>
+    <Product>WeihanLi.EntityFramework</Product>
+    <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
+    <RepositoryUrl>https://github.com/WeihanLi/WeihanLi.EntityFramework</RepositoryUrl>
+    <RepositoryType>git</RepositoryType>
+    <Copyright>Copyright 2019-2024 (c) WeihanLi</Copyright>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.0.1" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.2" PrivateAssets="all" />
+  </ItemGroup>
+
+</Project>

src/WeihanLi.EntityFramework/WeihanLi.EntityFramework.csproj

@@ -15,4 +15,7 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="$(EFVersion)" />
     <PackageReference Include="WeihanLi.Common" Version="$(CommonVersion)" />  
   </ItemGroup>
-</Project>
+  <ItemGroup>
+    <ProjectReference Include="..\WeihanLi.EntityFramework.SourceGenerator\WeihanLi.EntityFramework.SourceGenerator.csproj" />
+  </ItemGroup>
+</Project>