From f82c3b1c874a61696d64c49efff819dcbad8cebe Mon Sep 17 00:00:00 2001
From: Kouji Takao <kouji.takao@gmail.com>
Date: Sat, 28 Mar 2026 02:21:18 +0900
Subject: [PATCH] feat: add smalruby3 launcher command (rsdl replacement)

Build a native smalruby3 binary that wraps SDL_main + ruby_init,
solving the macOS main thread requirement for SDL2. Users can run
scripts with `smalruby3 script.rb` instead of `rsdl`.

- ext/smalruby3_launcher/: C source and extconf.rb (based on rsdl)
- gemspec: add launcher as second extension
- .standard.yml: exclude extconf.rb from lint (mkmf globals)

Closes #403

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 .claude/rules/ruby/rsdl.md                    | 54 -------------------
 .gitmodules                                   |  4 --
 ruby/rsdl                                     |  1 -
 ruby/smalruby3/.gitignore                     |  7 +++
 ruby/smalruby3/.standard.yml                  |  2 +
 ruby/smalruby3/exe/smalruby3                  | 18 +++++++
 .../ext/smalruby3_launcher/Makefile.in        | 26 +++++++++
 .../ext/smalruby3_launcher/extconf.rb         | 48 +++++++++++++++++
 .../smalruby3_launcher.c.in                   | 38 +++++++++++++
 ruby/smalruby3/smalruby3.gemspec              |  6 ++-
 10 files changed, 143 insertions(+), 61 deletions(-)
 delete mode 100644 .claude/rules/ruby/rsdl.md
 delete mode 160000 ruby/rsdl
 create mode 100644 ruby/smalruby3/.standard.yml
 create mode 100755 ruby/smalruby3/exe/smalruby3
 create mode 100644 ruby/smalruby3/ext/smalruby3_launcher/Makefile.in
 create mode 100644 ruby/smalruby3/ext/smalruby3_launcher/extconf.rb
 create mode 100644 ruby/smalruby3/ext/smalruby3_launcher/smalruby3_launcher.c.in

diff --git a/.claude/rules/ruby/rsdl.md b/.claude/rules/ruby/rsdl.md
deleted file mode 100644
index 7a636845c8a..00000000000
--- a/.claude/rules/ruby/rsdl.md
+++ /dev/null
@@ -1,54 +0,0 @@
----
-paths:
-  - "ruby/rsdl/**"
----
-
-# rsdl Development
-
-## Overview
-
-rsdl は macOS で Ruby + SDL2 を使う際に必要なコマンド。GC/メインスレッド問題を回避するラッパー。
-smalruby/rsdl は knu/rsdl の fork で、Ruby 4.0 対応を行っている。
-
-## Git Submodule
-
-`ruby/rsdl` は git submodule として管理されている。
-
-```
-origin:   https://github.com/smalruby/rsdl.git   (fork)
-upstream: https://github.com/knu/rsdl.git         (オリジナル)
-```
-
-### ブランチ構成
-
-| ブランチ | 内容 |
-|---|---|
-| `master` | upstream の master と同期 |
-| `smalruby/ruby-4.0-support` | ERB.new API 修正（Ruby 4.0 対応） |
-
-### PR 作成ルール
-
-1. **まず origin (smalruby/rsdl) に PR を作成**して動作確認
-2. 動作確認後、**upstream (knu/rsdl) にも PR を作成**
-3. upstream への PR を想定して、**機能ごとに細かくブランチ/PR を分ける**
-
-## ビルド
-
-```bash
-cd ruby/rsdl
-rbenv local 4.0.2   # or 3.3.9, 3.4.9
-ruby extconf.rb && make
-```
-
-## smalruby3 gem からの使い方
-
-```bash
-cd ruby/smalruby3
-../rsdl/rsdl -I../ruby-sdl2 -I../ruby-sdl2/lib -Ilib examples/01_move.rb
-```
-
-## 主な変更点（upstream との差分）
-
-- `extconf.rb`: `ERB.new(str, nil, '%')` → `ERB.new(str, trim_mode: '%')`
-- `extconf.rb`: `open(file, 'w')` → `File.open(file, 'w')`
-- `extconf.rb`: `file_in.result` → `file_in.result(binding)`
diff --git a/.gitmodules b/.gitmodules
index dec251f9eaa..5980f4e8ebf 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -2,7 +2,3 @@
 	path = ruby/ruby-sdl2
 	url = https://github.com/smalruby/ruby-sdl2.git
 	branch = smalruby/add-read-pixels
-[submodule "ruby/rsdl"]
-	path = ruby/rsdl
-	url = https://github.com/smalruby/rsdl.git
-	branch = smalruby/ruby-4.0-support
diff --git a/ruby/rsdl b/ruby/rsdl
deleted file mode 160000
index 21829ff07ad..00000000000
--- a/ruby/rsdl
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 21829ff07adee4045ea64c75bb68be5748f58d6d
diff --git a/ruby/smalruby3/.gitignore b/ruby/smalruby3/.gitignore
index dcc56be6f38..cb44f426ef9 100644
--- a/ruby/smalruby3/.gitignore
+++ b/ruby/smalruby3/.gitignore
@@ -7,5 +7,12 @@ lib/smalruby3/smalruby3_imageutil.bundle
 lib/smalruby3/smalruby3_imageutil.so
 *.gem
 
+# Launcher build artifacts
+ext/smalruby3_launcher/smalruby3
+ext/smalruby3_launcher/smalruby3_launcher.c
+ext/smalruby3_launcher/smalruby3_launcher.o
+ext/smalruby3_launcher/Makefile
+ext/smalruby3_launcher/mkmf.log
+
 # Docker marker
 .built
diff --git a/ruby/smalruby3/.standard.yml b/ruby/smalruby3/.standard.yml
new file mode 100644
index 00000000000..9b48f2b4e0b
--- /dev/null
+++ b/ruby/smalruby3/.standard.yml
@@ -0,0 +1,2 @@
+ignore:
+  - "ext/**/extconf.rb"
diff --git a/ruby/smalruby3/exe/smalruby3 b/ruby/smalruby3/exe/smalruby3
new file mode 100755
index 00000000000..30d22b2ae4a
--- /dev/null
+++ b/ruby/smalruby3/exe/smalruby3
@@ -0,0 +1,18 @@
+#!/usr/bin/env ruby
+
+# smalruby3 launcher wrapper — exec's the native SDL2 binary.
+# The native binary (smalruby3-bin) is installed to Ruby's bindir
+# by ext/smalruby3_launcher during gem install.
+
+require "rbconfig"
+
+bindir = RbConfig::CONFIG["bindir"]
+binary = File.join(bindir, "smalruby3-bin")
+
+# Fallback: development mode (built locally in ext/)
+unless File.exist?(binary)
+  binary = File.join(File.dirname(__FILE__, 2),
+    "ext", "smalruby3_launcher", "smalruby3")
+end
+
+exec binary, *ARGV
diff --git a/ruby/smalruby3/ext/smalruby3_launcher/Makefile.in b/ruby/smalruby3/ext/smalruby3_launcher/Makefile.in
new file mode 100644
index 00000000000..e0c583975c0
--- /dev/null
+++ b/ruby/smalruby3/ext/smalruby3_launcher/Makefile.in
@@ -0,0 +1,26 @@
+CC = <%= config['CC'] %>
+
+CFLAGS = <%= config['CFLAGS'] %>
+LIBS = <%= config['LIBS'] %>
+LDFLAGS = <%= config['LDFLAGS'] %>
+LIBPATH = <%= config['LIBPATH'] %>
+LIBRUBYARG = <%= config['LIBRUBYARG'] %>
+EXEEXT = <%= config['EXEEXT'] %>
+
+PROGRAM = smalruby3$(EXEEXT)
+
+OBJS = smalruby3_launcher.o
+
+.c.o:
+	$(CC) $(CFLAGS) -c $<
+
+all: $(PROGRAM)
+
+clean:
+	<%= config['RMALL'] %> $(PROGRAM) $(OBJS)
+
+install:
+	<%= config['INSTALL'] %> $(PROGRAM) <%= config['bindir'] %>/smalruby3-bin
+
+$(PROGRAM): $(OBJS)
+	$(CC) $(OBJS) $(LIBPATH) $(LDFLAGS) $(LIBRUBYARG) $(LIBS) -o $@
diff --git a/ruby/smalruby3/ext/smalruby3_launcher/extconf.rb b/ruby/smalruby3/ext/smalruby3_launcher/extconf.rb
new file mode 100644
index 00000000000..8abd608a67b
--- /dev/null
+++ b/ruby/smalruby3/ext/smalruby3_launcher/extconf.rb
@@ -0,0 +1,48 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# Build the smalruby3 launcher binary (SDL2 main thread wrapper).
+# Based on rsdl's extconf.rb.
+
+require "mkmf"
+require "erb"
+
+# Source directory where .in templates live
+srcdir = File.dirname(File.expand_path(__FILE__))
+
+dir_config("sdl")
+sdlconfig = with_config("sdl-config", "sdl-config")
+
+config = {}
+config["arch"] = RbConfig::CONFIG["arch"]
+config["INSTALL"] = RbConfig::CONFIG["INSTALL"]
+config["RMALL"] = RbConfig::CONFIG["RMALL"] || "rm -fr"
+config["CC"] = RbConfig::CONFIG["CC"]
+config["CFLAGS"] = RbConfig::CONFIG["CFLAGS"]
+config["CFLAGS"] += " -I\"#{$hdrdir}\"" if $hdrdir
+config["CFLAGS"] += " -I\"#{$arch_hdrdir}\"" if $arch_hdrdir
+config["CFLAGS"] += " " + `"#{sdlconfig}" --cflags` if sdlconfig && !sdlconfig.empty?
+config["LDFLAGS"] = RbConfig::CONFIG["LDFLAGS"]
+config["LIBS"] = RbConfig::CONFIG["LIBS"]
+config["LIBS"] += " " + `"#{sdlconfig}" --libs` if sdlconfig && !sdlconfig.empty?
+config["LIBPATH"] = RbConfig.expand(libpathflag)
+config["LIBRUBYARG"] = RbConfig::CONFIG["LIBRUBYARG"]
+config["EXEEXT"] = RbConfig::CONFIG["EXEEXT"]
+config["bindir"] = RbConfig::CONFIG["bindir"]
+# gem_dir: where the gem is installed (for install target)
+config["gem_dir"] = srcdir
+
+headers = []
+headers << "#define HAVE_RUBY_SYSINIT 1" if have_func("ruby_sysinit")
+headers << "#define HAVE_RUBY_RUN_NODE 1" if have_func("ruby_run_node")
+config["COMMON_HEADERS"] = ([(COMMON_HEADERS || "")] + headers).join("\n")
+
+%w[Makefile smalruby3_launcher.c].each do |file|
+  # Read template from source directory
+  template_path = File.join(srcdir, file + ".in")
+  template = ERB.new(File.read(template_path), trim_mode: "%")
+  message "creating %s\n" % file
+  File.open(file, "w") do |f|
+    f.print template.result(binding)
+  end
+end
diff --git a/ruby/smalruby3/ext/smalruby3_launcher/smalruby3_launcher.c.in b/ruby/smalruby3/ext/smalruby3_launcher/smalruby3_launcher.c.in
new file mode 100644
index 00000000000..32ebfa8edba
--- /dev/null
+++ b/ruby/smalruby3/ext/smalruby3_launcher/smalruby3_launcher.c.in
@@ -0,0 +1,38 @@
+/* smalruby3 launcher — SDL2 main thread wrapper for macOS */
+/* Based on rsdl (https://github.com/knu/rsdl) */
+
+#include <ruby.h>
+<%= config['COMMON_HEADERS'] %>
+#include <SDL.h>
+#include "SDL_main.h"
+#ifdef HAVE_LOCALE_H
+#include <locale.h>
+#endif
+
+#ifdef RUBY_GLOBAL_SETUP
+RUBY_GLOBAL_SETUP
+#endif
+
+int main(int argc, char **argv)
+{
+#ifdef HAVE_LOCALE_H
+  setlocale(LC_CTYPE, "");
+#endif
+
+#ifdef HAVE_RUBY_SYSINIT
+  ruby_sysinit(&argc, &argv);
+#endif
+  {
+#ifdef RUBY_INIT_STACK
+    RUBY_INIT_STACK;
+#endif
+    ruby_init();
+#ifdef HAVE_RUBY_RUN_NODE
+    return ruby_run_node(ruby_options(argc, argv));
+#else
+    ruby_options(argc, argv);
+    ruby_run();
+    return 0;
+#endif
+  }
+}
diff --git a/ruby/smalruby3/smalruby3.gemspec b/ruby/smalruby3/smalruby3.gemspec
index 97127901c59..1c2bd91fefc 100644
--- a/ruby/smalruby3/smalruby3.gemspec
+++ b/ruby/smalruby3/smalruby3.gemspec
@@ -16,9 +16,11 @@ Gem::Specification.new do |spec|
   spec.license = "MIT"
   spec.required_ruby_version = ">= 3.3"
 
-  spec.files = Dir["lib/**/*.rb", "lib/**/*.json", "ext/**/*.{rb,rs,toml}", "assets/**/*", "LICENSE", "README.md"]
+  spec.files = Dir["lib/**/*.rb", "lib/**/*.json", "ext/**/*.{rb,rs,toml,in,c.in}", "exe/*", "assets/**/*", "LICENSE", "README.md"]
+  spec.bindir = "exe"
+  spec.executables = ["smalruby3"]
   spec.require_paths = ["lib"]
-  spec.extensions = ["ext/smalruby3_imageutil/extconf.rb"]
+  spec.extensions = ["ext/smalruby3_imageutil/extconf.rb", "ext/smalruby3_launcher/extconf.rb"]
 
   spec.add_dependency "ruby-sdl2", "~> 0.3"
   spec.add_dependency "rb_sys", "~> 0.9"