Add rake task to download prebuilt binaries

To allow developers skipping CRuby builds when editing npm packages

Author: kateinoigakukun

Rakefile

@@ -78,4 +78,44 @@ namespace :build do
       end
     end
   end
+
+  desc "Clean build directories"
+  task :clean do
+    rm_rf "./build"
+    rm_rf "./rubies"
+  end
+
+  desc "Download prebuilt Ruby"
+  task :download_prebuilt, :tag do |t, args|
+    require "ruby_wasm/build_system/downloader"
+
+    release =
+      if args[:tag]
+        url = "https://api.github.com/repos/ruby/ruby.wasm/releases/tags/#{args[:tag]}"
+        OpenURI.open_uri(url) do |f|
+          JSON.load(f.read)
+        end
+      else
+        url = "https://api.github.com/repos/ruby/ruby.wasm/releases?per_page=1"
+        OpenURI.open_uri(url) do |f|
+          JSON.load(f.read)[0]
+        end
+      end
+
+    puts "Downloading from release \"#{release["tag_name"]}\""
+
+    rubies_dir = "./rubies"
+    downloader = RubyWasm::Downloader.new
+    rm_rf rubies_dir
+    mkdir_p rubies_dir
+
+    assets = release["assets"].select { |a| a["name"].end_with? ".tar.gz" }
+    assets.each_with_index do |asset, i|
+      url = asset["browser_download_url"]
+      tarball = File.join("rubies", asset["name"])
+      rm_rf tarball, verbose: false
+      downloader.download(url, tarball, "[%2d/%2d] Downloading #{File.basename(url)}" % [i + 1, assets.size])
+      sh "tar xzf #{tarball} -C ./rubies"
+    end
+  end
 end

lib/ruby_wasm/build_system/downloader.rb

@@ -0,0 +1,28 @@
+module RubyWasm
+  class Downloader
+    def format_size(size)
+      units = %w[B KB MB GB TB]
+      unit = 0
+      while size > 1024 and unit < units.size - 1
+        size /= 1024.0
+        unit += 1
+      end
+      "%s #{units[unit]}" % size.round(2)
+    end
+
+    def download(url, dest, message)
+      require "open-uri"
+      content_length = nil
+      uri = URI.parse(url)
+      OpenURI.open_uri(
+        uri,
+        content_length_proc: ->(len) { content_length = len },
+        progress_proc: ->(size) do
+          print "\r#{message} (#{format_size(content_length)}) %.2f%%" %
+                  (size.to_f / content_length * 100)
+        end
+      ) { |f| File.open(dest, "wb") { |out| out.write f.read } }
+      puts "\r"
+    end
+  end
+end

lib/ruby_wasm/build_system/product/crossruby.rb

@@ -78,7 +78,7 @@ def do_install_rb(crossruby)
   end
 
   class CrossRubyProduct < AutoconfProduct
-    attr_reader :source, :toolchain, :build, :configure
+    attr_reader :source, :toolchain, :build, :configure, :install_task
     attr_accessor :user_exts,
                   :wasmoptflags,
                   :cppflags,
@@ -149,15 +149,17 @@ def define_task
           sh "make install DESTDIR=#{install_dir}", chdir: build_dir
         end
 
-      desc "Build #{name}"
-      task name => [@configure, install, dest_dir] do
-        artifact = "rubies/ruby-#{name}.tar.gz"
-        next if File.exist?(artifact)
-        rm_rf dest_dir
-        cp_r install_dir, dest_dir
-        @user_exts.each { |ext| ext.do_install_rb(self) }
-        sh "tar cfz #{artifact} -C rubies #{name}"
-      end
+      @install_task =
+        task artifact => [@configure, install, dest_dir] do
+          rm_rf dest_dir
+          cp_r install_dir, dest_dir
+          @user_exts.each { |ext| ext.do_install_rb(self) }
+          sh "tar cfz #{artifact} -C rubies #{name}"
+        end
+    end
+
+    def build
+      @install_task.invoke
     end
 
     def name
@@ -184,14 +186,21 @@ def with_zlib(zlib)
 
     def with_wasi_vfs(wasi_vfs)
       @wasi_vfs = wasi_vfs
-      install_task = wasi_vfs.install_task
-      @dep_tasks << install_task if install_task
+      wasi_vfs.install_task&.tap { |t| @dep_tasks << t }
     end
 
     def dest_dir
       File.join(@rubies_dir, name)
     end
 
+    def artifact
+      File.join(@rubies_dir, "ruby-#{name}.tar.gz")
+    end
+
+    def built?
+      File.exist?(artifact)
+    end
+
     def extinit_obj
       "#{ext_build_dir}/extinit.o"
     end

lib/ruby_wasm/rake_task.rb

@@ -72,6 +72,11 @@ def initialize(
     @crossruby.with_wasi_vfs @wasi_vfs
 
     @crossruby.define_task
+
+    task name do
+      next if @crossruby.built?
+      @crossruby.build
+    end
   end
 
   def hexdigest