Detect WASI exec-model by adhoc way for now

Author: kateinoigakukun

lib/ruby_wasm/packager/core.rb

@@ -59,6 +59,14 @@ def specs_with_extensions
       end
     end
 
+    def wasi_exec_model
+      # TODO: Detect WASI exec-model from binary exports (_start or _initialize)
+      use_js_gem = @packager.specs.any? do |spec|
+        spec.name == "js"
+      end
+      use_js_gem ? "reactor" : "command"
+    end
+
     def cache_key(digest)
       raise NotImplementedError
     end
@@ -127,8 +135,7 @@ def _link_gem_exts(executor, build, gem_home)
         wasi_sdk_path = toolchain.wasi_sdk_path
         libraries << File.join(wasi_sdk_path, "share/wasi-sysroot/lib/wasm32-wasi", lib)
       end
-      # TODO: Detect WASI exec-model from binary exports (_start or _initialize)
-      wasi_adapter = RubyWasm::Packager::ComponentAdapter.wasi_snapshot_preview1("reactor")
+      wasi_adapter = RubyWasm::Packager::ComponentAdapter.wasi_snapshot_preview1(wasi_exec_model)
       adapters = [wasi_adapter]
       dl_openable_libs = []
       dl_openable_libs << [File.join(ruby_root, "usr"), Dir.glob(File.join(ruby_root, "usr", "local", "lib", "ruby", "**", "*.so"))]
@@ -334,7 +341,7 @@ def link_gem_exts(executor, gem_home, module_bytes)
       linker.module(module_bytes)
       linker.adapter(
         "wasi_snapshot_preview1",
-        File.binread(RubyWasm::Packager::ComponentAdapter.wasi_snapshot_preview1("reactor"))
+        File.binread(RubyWasm::Packager::ComponentAdapter.wasi_snapshot_preview1(wasi_exec_model))
       )
 
       linker.encode()