Allow Dart code to register service protocol handlers

runtime/vm/service.cc

Index: runtime/vm/service.cc
diff --git a/runtime/vm/service.cc b/runtime/vm/service.cc
index 6f4fd03d4d14791d0f72abcb848b08fda3063987..3868b9ca7dd8ad18ef946a3f5d6da57e66553e73 100644
--- a/runtime/vm/service.cc
+++ b/runtime/vm/service.cc
@@ -585,6 +585,16 @@ void Service::InvokeMethod(Isolate* isolate, const Array& msg) {
       return;
     }
 
+    if (ExtensionHandlerExists(method_name)) {
+      InvokeExtensionHandler(method_name,
+                             param_keys,
+                             param_values,
+                             reply_port,
+                             seq);
+      // The reply is posted asynchronously.
+      return;
+    }
+
     PrintUnrecognizedMethodError(&js);
     js.PostReply();
     return;
@@ -869,6 +879,46 @@ EmbedderServiceHandler* Service::FindRootEmbedderHandler(
 }
 
 
+bool Service::ExtensionHandlerExists(const String& method) {
+  ASSERT(!method.IsNull());
+  const Library& developer_lib = Library::Handle(Library::DeveloperLibrary());
+  ASSERT(!developer_lib.IsNull());
+  const Function& extension_exists = Function::Handle(
+      developer_lib.LookupLocalFunction(Symbols::_extensionExists()));
+  ASSERT(!extension_exists.IsNull());
+  const Array& arguments = Array::Handle(Array::New(1));
+  ASSERT(!arguments.IsNull());
+  arguments.SetAt(0, method);
+  return (DartEntry::InvokeFunction(extension_exists, arguments) ==
+          Object::bool_true().raw());
+}
+
+
+bool Service::InvokeExtensionHandler(const String& method_name,
+                                     const Array& parameter_keys,
+                                     const Array& parameter_values,
+                                     const Instance& reply_port,
+                                     const Instance& id) {
+  ASSERT(!method_name.IsNull());
+  ASSERT(!parameter_keys.IsNull());
+  ASSERT(!parameter_values.IsNull());
+  ASSERT(!reply_port.IsNull());
+  const Library& developer_lib = Library::Handle(Library::DeveloperLibrary());
+  ASSERT(!developer_lib.IsNull());
+  const Function& invoke_extension = Function::Handle(
+      developer_lib.LookupLocalFunction(Symbols::_invokeExtension()));
+  ASSERT(!invoke_extension.IsNull());
+  const Array& arguments = Array::Handle(Array::New(5));
+  arguments.SetAt(0, method_name);
+  arguments.SetAt(1, parameter_keys);
+  arguments.SetAt(2, parameter_values);
+  arguments.SetAt(3, reply_port);
+  arguments.SetAt(4, id);
+  return (DartEntry::InvokeFunction(invoke_extension, arguments) ==
+          Object::bool_true().raw());
+}
+
+
 static const MethodParameter* get_isolate_params[] = {
   ISOLATE_PARAMETER,
   NULL,