LoggerMessageGenerator.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Runtime.CompilerServices;
using System.Text;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Text;

[assembly: System.Resources.NeutralResourcesLanguage("en-us")]

namespace Microsoft.Extensions.Logging.Generators
{
    [Generator]
    public partial class LoggerMessageGenerator : ISourceGenerator
    {
        [ExcludeFromCodeCoverage]
        public void Initialize(GeneratorInitializationContext context)
        {
            context.RegisterForSyntaxNotifications(SyntaxReceiver.Create);
        }

        [ExcludeFromCodeCoverage]
        public void Execute(GeneratorExecutionContext context)
        {
            if (context.SyntaxReceiver is not SyntaxReceiver receiver || receiver.ClassDeclarations.Count == 0)
            {
                // nothing to do yet
                return;
            }

            var p = new Parser(context.Compilation, context.ReportDiagnostic, context.CancellationToken);
            IReadOnlyList<LoggerClass> logClasses = p.GetLogClasses(receiver.ClassDeclarations);
            if (logClasses.Count > 0)
            {
                var e = new Emitter();
                string result = e.Emit(logClasses, context.CancellationToken);
    
                context.AddSource("LoggerMessage", SourceText.From(result, Encoding.UTF8));
            }
        }

        [ExcludeFromCodeCoverage]
        private sealed class SyntaxReceiver : ISyntaxReceiver
        {
            internal static ISyntaxReceiver Create()
            {
                return new SyntaxReceiver();
            }

            public List<ClassDeclarationSyntax> ClassDeclarations { get; } = new ();

            public void OnVisitSyntaxNode(SyntaxNode syntaxNode)
            {
                if (syntaxNode is ClassDeclarationSyntax classSyntax)
                {
                    ClassDeclarations.Add(classSyntax);
                }
            }
        }
    }
}