feat: add smalruby3 launcher command (rsdl replacement)

.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

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

ruby/smalruby3/.standard.yml

@@ -0,0 +1,2 @@
+ignore:
+  - "ext/**/extconf.rb"

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

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 $@

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

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
+  }
+}

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"