Migrate to Extension Gem using rake-compiler Part 1

Rakefile

@@ -1,92 +1,8 @@
 # frozen_string_literal: true
-
-warn 'only CRuby supported', category: :experimental if 'ruby' != RUBY_ENGINE
-
-
-# Defines #
-
-# @return `"<architecture>/<platform>"`
-# @see RbConfig::CONFIG
-OS = File.join(
-  case target = RbConfig::CONFIG['target_cpu']
-  when 'x64'
-    'x86_64'
-  else
-    warn "target_cpu `#{target}` not supported", category: :experimental
-    ".#{target}"
-  end,
-  case target = RbConfig::CONFIG['target_os']
-  when 'mingw32'
-    'windows'
-  else
-    warn "target_os `#{target}` not supported", category: :experimental
-    ".#{target}"
-  end
-)
-
-# RubyInstaller has its stuff in its own self-contained folder
-# @return [boolish] the `RubyInstaller` module for Windows RubyInstaller, or `nil` for non-RubyInstaller
-RubyInstaller ||= nil
-warn 'non-RubyInstaller2 not supported', category: :experimental unless RubyInstaller
-
-# C sources directory
-# @return `"src"`
-SRC = 'src'
-# Output root directory
-# @return `"build"`
-BIN = 'build'
-# Output directory
-# @return `"build/<architecture>/<platform>/"`
-# @see OS
-OUT = File.join(BIN, OS, '')
-
-# @return `libruby.so`’s directory: `"/<path>/<to>"`
-# @see LIBRUBY_NAME
-LIBRUBY_DIR = RbConfig::CONFIG[RubyInstaller ? 'bindir' : 'libdir']
-# @return `libruby.so`, the file name (dependant on platform and possibly architecture)
-# @see LIBRUBY_DIR
-LIBRUBY_NAME = RbConfig::CONFIG['LIBRUBY_SO']
-i_h_dir = "-I#{RbConfig::CONFIG['rubyhdrdir']}"
-i_arch_h_dir = "-I#{RbConfig::CONFIG['rubyarchhdrdir']}"
-l_libruby_dir = "-L#{LIBRUBY_DIR}"
-l_libruby_name = "-l:#{LIBRUBY_NAME}"
-
-rubyarchdir = RbConfig::CONFIG['rubyarchdir']
-# Assume `rubyarchdir` always starts with `prefix`
-directory out_archdir =
-  File.join(OUT, rubyarchdir[RbConfig::CONFIG['prefix'].size..] || '')
-out_enc_dir = File.join(out_archdir, 'enc')
-file_create out_enc_dir => out_archdir
-
-# symlinks of `libruby` & dependencies in the output directory and their originals
-# @return `{"build/<architecture>/<platform>/<lib.so>" => "/<path>/<to>/<lib.so>", …}`
-LIBS = {
-  File.join(OUT, LIBRUBY_NAME) => File.join(LIBRUBY_DIR, LIBRUBY_NAME),
-  out_enc_dir => File.join(rubyarchdir, 'enc')
-}
-if RubyInstaller
-  %w[libgmp-10.dll].each do|lib|
-    LIBS[File.join(OUT, lib)] =
-      File.join(LIBRUBY_DIR, 'ruby_builtin_dlls', lib)
-  end
-end
-
-rake_output_message "<architecture/platform>\t#{OS}"
-
-
-# C #
-
-src_dir_size = SRC.size
-# C sources and file names of their corresponding  intermediate `.o`s
-# @return `{"src/*.c" => "*.o"}`
-# @see SRC
-C__O_NAMES = Dir[File.join(SRC, '**', '*.c'), sort: false].to_h {|source| [
-  source,
-  source[src_dir_size..].tap { _1[-1] = 'o' }
-] }
+require 'rake/extensiontask'
 
 # Build modes and their compiler flags
-# @return `{'debug' => ["flag", …], 'release' => …}`
+# @return `{"debug" => ["flag", …], "release" => …}`
 BUILD_FLAGS = {
   'debug' => %w[
   ],
@@ -95,104 +11,62 @@ BUILD_FLAGS = {
     -O2
   ]
 }
-BUILD_FLAGS.map do|build, flags|
-  out = File.join(OUT, "#{build}.lib")
-  o_dir_name = ".#{build}.o"
-  directory o_dir = File.join(OUT, o_dir_name)
-
-  # Compile Object Binaries (`.o`)
-  C__O_NAMES.map do|source, o_name|
-    o0 = File.join(o_dir, o_name)
-    directory o0_dir = File.dirname(o0)
-    file o0 => [source, o0_dir] do
-      sh('gcc',
-         *flags,
-         '-c',
-         "-o#{o0}",
-         '-fPIC',
-         '-Iinclude',
-         i_h_dir,
-         i_arch_h_dir,
-         source
-      )
-    end
-    o0
-  end => o
-
-  # Link Shared Library (`.so`)
-  file out => o do
-    sh('gcc',
-       *flags,
-       '-shared',
-       '-fPIC',
-       "-o#{out}",
-       *o,
-       l_libruby_dir,
-       l_libruby_name
-    )
-  end
-  multitask build => [*o, out]
-
-  o_dir
-end => o_dirs # ["…/.debug.o", …]`
-
 
-# Ruby #
+# sh('gcc',
+#    *flags,
+#   …
+# )
 
-hash_files = %w[core editor].to_h do|api_type|
-  tsv = File.join BIN, "#{api_type}.hashes.tsv"
-  # Each task executes at most once
-  file tsv => :extension_api
-  [api_type, tsv]
+# C
+Rake::ExtensionTask.new 'godot_rb' do|ext|
+  # ext.config_options << '--with-foo'
+  ext.source_pattern = '**/*.c'
+  ext.no_native = true
 end
 
-extension_api = File.join 'include', 'godot', 'extension_api.json'
-# Database of method hashes
-# ```
-# Class
-# method␉12345
-# ```
-task :extension_api => [BIN, extension_api] do
-  require 'json'
-  json = JSON.load_file extension_api
-  files = hash_files.transform_values do|tsv|
-    File.open tsv, 'w'
-  rescue => e
-    warn e.full_message
-  end
-  begin
-    json['classes'].each do|klass_data|
-      files[klass_data['api_type']]&.then do|tsv|
-        tsv.puts klass_data['name']
-        klass_data['methods']&.each do|method_data|
-          method_data['hash']&.then { tsv.puts "#{method_data['name']}\t#{_1}" }
-        end
-      end
-    end
-  ensure
-    files.each_value { _1&.close }
-  end
-end
+# # Ruby #
+#
+# hash_files = %w[core editor].to_h do|api_type|
+#   tsv = File.join BIN, "#{api_type}.hashes.tsv"
+#   # Each task executes at most once
+#   file tsv => :extension_api
+#   [api_type, tsv]
+# end
+#
+# extension_api = File.join 'include', 'godot', 'extension_api.json'
+# # Database of method hashes
+# # ```
+# # Class
+# # method␉12345
+# # ```
+# task :extension_api => [BIN, extension_api] do
+#   require 'json'
+#   json = JSON.load_file extension_api
+#   files = hash_files.transform_values do|tsv|
+#     File.open tsv, 'w'
+#   rescue => e
+#     warn e.full_message
+#   end
+#   begin
+#     json['classes'].each do|klass_data|
+#       files[klass_data['api_type']]&.then do|tsv|
+#         tsv.puts klass_data['name']
+#         klass_data['methods']&.each do|method_data|
+#           method_data['hash']&.then { tsv.puts "#{method_data['name']}\t#{_1}" }
+#         end
+#       end
+#     end
+#   ensure
+#     files.each_value { _1&.close }
+#   end
+# end
 
 
 # Tasks #
 
-desc 'build Godot.rb for debug builds'
-task default: [BUILD_FLAGS.each_key.first, :additional_files]
-desc 'build Godot.rb for all build types'
-task all: (BUILD_FLAGS.keys << 'additional_files')
-
-LIBS.each {|symlink, lib| file_create symlink => OUT do
-  ln_sf lib, symlink
-end }
-multitask additional_files: ( LIBS.keys.push *hash_files.values )
-
-
-desc "delete the intermediate directories such as `#{o_dirs.first}`"
-task :mostlyclean do
-  rm_rf o_dirs
-end
-desc "delete the output directory `#{OUT}`"
-task :clean do
-  rm_rf OUT
-end
+# desc 'build Godot.rb for debug builds'
+# task default: [BUILD_FLAGS.each_key.first, :additional_files]
+# desc 'build Godot.rb for all build types'
+# task all: (BUILD_FLAGS.keys << 'additional_files')
+#
+# multitask additional_files: hash_files.values

ext/godot_rb/cleanup.c

@@ -1,4 +1,4 @@
-#include "ruby/variants.h"
+#include "variants.h"
 
 static void core(void) {
   if RB_UNLIKELY(ruby_cleanup(EXIT_SUCCESS))

ext/godot_rb/extconf.rb

@@ -1,2 +1,13 @@
 require 'mkmf'
+
+# Detect (Windows) stand-alone MinGW without MSYS2 (AKA DevKit)
+unless CROSS_COMPILING or RbConfig::CONFIG['build_os'] != 'mingw32' or find_executable 'msys2'
+  # Monkeypatch {MakeMakefile#find_header} to prevent translation to MSYS `/C/some/path/`
+  def mkintpath(path) = path
+end
+
+include = File.expand_path '../../include/', __FILE__
+find_header 'godot_rb.h', include
+find_header 'godot/gdextension_interface.h', include
+
 create_makefile 'godot_rb'

ext/godot_rb/godot_rb.c

@@ -112,3 +112,5 @@ bool godot_rb_protect(void (* function)(va_list* args), ...) {
   }
   return true;
 }
+
+void Init_godot_rb() {}

ext/godot_rb/setup.c

@@ -1,5 +1,5 @@
 #include "setup.h"
-#include "ruby/variants.h"
+#include "variants.h"
 
 /**
   Ruby keeps a copy of the argc/v pointers’ contents, though it seems to only use `argv[0]` occasionally.