FEATURE: add wasm support

Previously we had no way of pumping the message loop, this meant that when
we instansiated wasm the promise would never resolve.

This demonstrates how to call wasm from Ruby using the new
context.isolate.pump_message_loop

ext/mini_racer_extension/mini_racer_extension.cc

@@ -779,6 +779,19 @@ static VALUE rb_isolate_low_memory_notification(VALUE self) {
     return Qnil;
 }
 
+static VALUE rb_isolate_pump_message_loop(VALUE self) {
+    IsolateInfo* isolate_info;
+    Data_Get_Struct(self, IsolateInfo, isolate_info);
+
+    if (current_platform == NULL) return Qfalse;
+
+    if (platform::PumpMessageLoop(current_platform.get(), isolate_info->isolate)){
+	return Qtrue;
+    } else {
+	return Qfalse;
+    }
+}
+
 static VALUE rb_context_init_unsafe(VALUE self, VALUE isolate, VALUE snap) {
     ContextInfo* context_info;
     Data_Get_Struct(self, ContextInfo, context_info);
@@ -1668,7 +1681,7 @@ extern "C" {
 
         rb_define_method(rb_cIsolate, "idle_notification", (VALUE(*)(...))&rb_isolate_idle_notification, 1);
         rb_define_method(rb_cIsolate, "low_memory_notification", (VALUE(*)(...))&rb_isolate_low_memory_notification, 0);
-
+        rb_define_method(rb_cIsolate, "pump_message_loop", (VALUE(*)(...))&rb_isolate_pump_message_loop, 0);
         rb_define_private_method(rb_cIsolate, "init_with_snapshot",(VALUE(*)(...))&rb_isolate_init_with_snapshot, 1);
 
         rb_define_singleton_method(rb_cPlatform, "set_flag_as_str!", (VALUE(*)(...))&rb_platform_set_flag_as_str, 1);

mini_racer.gemspec

@@ -30,6 +30,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "rake", ">= 12.3.3"
   spec.add_development_dependency "minitest", "~> 5.0"
   spec.add_development_dependency "rake-compiler"
+  spec.add_development_dependency "m"
 
   spec.add_dependency 'libv8', '> 7.3'
   spec.require_paths = ["lib", "ext"]

test/mini_racer_test.rb

@@ -873,4 +873,49 @@ raise FooError, "I like foos"
     context.attach('myFunctionLogger', ->(property) { })
     context.eval(js)
   end
+
+  def test_promise
+    context = MiniRacer::Context.new()
+    context.eval <<~JS
+      var x = 0;
+      async function test() {
+        return 99;
+      }
+
+      test().then(v => x = v);
+    JS
+
+    context.isolate.run_microtasks
+    v = context.eval("x");
+    assert_equal(v, 99)
+  end
+
+  def test_webassembly
+    context = MiniRacer::Context.new()
+    context.eval("let instance = null;")
+    filename = File.expand_path("../support/add.wasm", __FILE__)
+    context.attach("loadwasm", proc {|f| File.read(filename).each_byte.to_a})
+    context.attach("print", proc {|f| puts f})
+
+    context.eval("function module() { print(arguments)  }")
+
+    context.eval <<~JS
+    WebAssembly
+      .instantiate(new Uint8Array(loadwasm()), {
+        wasi_snapshot_preview1: {
+          proc_exit: function() { print("exit"); },
+          args_get: function() { return 0 },
+          args_sizes_get: function() { return 0 }
+        }
+      })
+      .then(i => { instance = i["instance"];})
+      .catch(e => print(e.toString()));
+    JS
+
+    while !context.eval("instance") do
+      context.isolate.pump_message_loop
+    end
+
+    assert_equal(3, context.eval("instance.exports.add(1,2)"))
+  end
 end