在源代码生成器中添加非 C# 文件

Question

I'm creating a source generator that creates Typescript utilities based on user C# code, right now the only efficient way to create a file is AddSource() method, which can only create *.cs files.

I need to create *.ts files (or *.js ), using File.Write* is also a pain, because the path and referencing project are unknown ( Environment.CurrentDirectory will return the generator path which is not even close to user project) to generator, currently the only way to find the path is:

var baseFilePath = context.Compilation.SyntaxTrees.First(x => x.HasCompilationUnitRoot).FilePath;

var myDir = Path.Combine(Path.GetDirectoryName(baseFilePath)!, "tsFiles");

from here .

which as you can see is not really nice and safe and it would be a performance killer since it cannot be used in Initialize method, it has to be in Execute method which will execute forever and you have to either put an if statement to check File.Exists() or it will create that file for ever.

Considering all these, what is the most efficient way to create non-C# files (both in startup and execution time)

Answer 1

For either a ISourceGenerator or IIncrementalGenerator, you should be able to access the target project's "build_property.projectdir" value from AnalyzerConfigOptions.

The following is a gist that I use for the same thing in an IIncrementalGenerator.

IncrementalValueProvider<string?> projectDirProvider = context.AnalyzerConfigOptionsProvider
    .Select(static (provider, _) => { 
        provider.GlobalOptions.TryGetValue("build_property.projectdir", out string? projectDirectory);

        return projectDirectory;
});
   

context.RegisterSourceOutput(
    projectDirProvider, 
    static (context, source) => {
    
    string? projectDirectory = source;

});

This will give you the base/root directory of your target project and from there you should be able to use System.IO for what you need.