[Rgen] Establish transformer tool setup (#21784)

Co-authored-by: GitHub Actions Autoformatter <[email protected]>

src/rgen/Microsoft.Macios.Transformer/Main.cs

@@ -0,0 +1,13 @@
+using System.CommandLine;
+using System.CommandLine.Builder;
+using System.CommandLine.Parsing;
+using Microsoft.Macios.Transformer;
+
+
+//TODO: logging infra
+// add cli header stuff
+var parser = new CommandLineBuilder (new TransformCommand ())
+			.UseDefaults ()
+			.Build ();
+
+return await parser.InvokeAsync (args).ConfigureAwait (false);

src/rgen/Microsoft.Macios.Transformer/Microsoft.Macios.Transformer.csproj

@@ -1,10 +1,22 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
-  <PropertyGroup>
-    <OutputType>Exe</OutputType>
-    <TargetFramework>net$(BundledNETCoreAppTargetFrameworkVersion)</TargetFramework>
-    <ImplicitUsings>enable</ImplicitUsings>
-    <Nullable>enable</Nullable>
-  </PropertyGroup>
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net$(BundledNETCoreAppTargetFrameworkVersion)</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Microsoft.CodeAnalysis.Common" Version="4.9.2" />
+        <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.9.2" />
+        <PackageReference Include="System.CommandLine" Version="2.0.0-beta4.22272.1" />
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\Microsoft.Macios.Generator\Microsoft.Macios.Generator.csproj" PrivateAssets="all" />
+        <None Include="$(OutputPath)\*.dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />
+    </ItemGroup>
 
 </Project>

src/rgen/Microsoft.Macios.Transformer/TransformCommand.cs

@@ -0,0 +1,38 @@
+using System.CommandLine;
+
+namespace Microsoft.Macios.Transformer;
+
+public class TransformCommand : Command {
+
+	public TransformCommand () : base ("rgen-transform", "command to convert outdated bindings to be rgen compatible")
+	{
+		var input = new Option<string> (["--input", "-i"], "input directory to search for bgen bindings") {
+			//single file support?
+			IsRequired = true
+		};
+		AddOption (input);
+
+		var output = new Option<string> (["--output", "-o"], "output directory to write rgen bindings") {
+			IsRequired = true
+		};
+		AddOption (output);
+
+		AddValidator (result => {
+			if (!Directory.Exists (result.GetValueForOption (input))) {
+				result.ErrorMessage = "Input directory does not exist";
+			}
+			if (!Directory.Exists (result.GetValueForOption (output))) {
+				Directory.CreateDirectory (result.GetValueForOption (output)!);
+			}
+		});
+		// this.AddOption (new Option<bool> (new string [] { "--verbose", "-v" }, "verbose output"));
+
+		this.SetHandler (Execute);
+	}
+
+	public async Task Execute ()
+	{
+		// placeholder for loading/parsing/transforming/writing components
+		await Task.CompletedTask;
+	}
+}