From c94d1565c3409a04f4b9384f64e92565258db90b Mon Sep 17 00:00:00 2001
From: Jacob Domagala <domagala.jacob@gmail.com>
Date: Wed, 7 Dec 2022 22:58:11 +0100
Subject: [PATCH] #2027: Objgroup: Add separate invoke functions for different
 return types

---
 src/vt/objgroup/manager.h      | 23 +++++++++++++-
 src/vt/objgroup/manager.impl.h | 58 ++++++++++++++++++++++++++++++++--
 2 files changed, 78 insertions(+), 3 deletions(-)

diff --git a/src/vt/objgroup/manager.h b/src/vt/objgroup/manager.h
index a43c107501..dc45a430bd 100644
--- a/src/vt/objgroup/manager.h
+++ b/src/vt/objgroup/manager.h
@@ -46,6 +46,7 @@
 
 #include "vt/config.h"
 #include "vt/runtime/component/component_pack.h"
+#include "vt/utils/static_checks/function_ret_check.h"
 #include "vt/objgroup/common.h"
 #include "vt/objgroup/manager.fwd.h"
 #include "vt/objgroup/proxy/proxy_objgroup.h"
@@ -237,7 +238,27 @@ struct ObjGroupManager : runtime::component::Component<ObjGroupManager> {
    * \param[in] args function arguments
    */
   template <typename ObjT, typename Type, Type f, typename... Args>
-  decltype(auto) invoke(ProxyElmType<ObjT> proxy, Args&&... args);
+  util::NotCopyable<Type> invoke(ProxyElmType<ObjT> proxy, Args&&... args);
+
+  /**
+   * \internal \brief Invoke function 'f' on an element of the object group
+   * The function will be invoked inline without going through scheduler
+   *
+   * \param[in] proxy proxy to the object group
+   * \param[in] args function arguments
+   */
+  template <typename ObjT, typename Type, Type f, typename... Args>
+  util::Copyable<Type> invoke(ProxyElmType<ObjT> proxy, Args&&... args);
+
+  /**
+   * \internal \brief Invoke function 'f' on an element of the object group
+   * The function will be invoked inline without going through scheduler
+   *
+   * \param[in] proxy proxy to the object group
+   * \param[in] args function arguments
+   */
+  template <typename ObjT, typename Type, Type f, typename... Args>
+  util::IsVoidReturn<Type> invoke(ProxyElmType<ObjT> proxy, Args&&... args);
 
   /**
    * \internal \brief Broadcast a message to all nodes in object group
diff --git a/src/vt/objgroup/manager.impl.h b/src/vt/objgroup/manager.impl.h
index dffb5f7917..6522f0d179 100644
--- a/src/vt/objgroup/manager.impl.h
+++ b/src/vt/objgroup/manager.impl.h
@@ -236,7 +236,27 @@ void ObjGroupManager::invoke(
 }
 
 template <typename ObjT, typename Type, Type f, typename... Args>
-decltype(auto)
+util::IsVoidReturn<Type>
+ObjGroupManager::invoke(ProxyElmType<ObjT> proxy, Args&&... args) {
+  auto const dest_node = proxy.getNode();
+  auto const this_node = theContext()->getNode();
+
+  auto ptr = get(proxy);
+  vtAssert(
+    dest_node == this_node,
+    fmt::format(
+      "Attempting to invoke handler on node:{} instead of node:{}!\n",
+      this_node, dest_node));
+
+  runnable::makeRunnableVoid(false, uninitialized_handler, this_node)
+    .withExplicitTask([&]{
+      runnable::invoke<Type, f>(ptr, std::forward<Args>(args)...);
+    })
+    .run();
+}
+
+template <typename ObjT, typename Type, Type f, typename... Args>
+util::Copyable<Type>
 ObjGroupManager::invoke(ProxyElmType<ObjT> proxy, Args&&... args) {
   auto const dest_node = proxy.getNode();
   auto const this_node = theContext()->getNode();
@@ -249,7 +269,41 @@ ObjGroupManager::invoke(ProxyElmType<ObjT> proxy, Args&&... args) {
     )
   );
 
-  return runnable::invoke<Type, f>(get(proxy), std::forward<Args>(args)...);
+  util::Copyable<Type> result;
+
+  runnable::makeRunnableVoid(false, uninitialized_handler, dest_node)
+    .withExplicitTask([&] {
+      result = runnable::invoke<Type, f>(get(proxy), std::forward<Args>(args)...);
+    })
+    .run();
+
+  return result;
+}
+
+template <typename ObjT, typename Type, Type f, typename... Args>
+util::NotCopyable<Type>
+ObjGroupManager::invoke(ProxyElmType<ObjT> proxy, Args&&... args) {
+  auto const dest_node = proxy.getNode();
+  auto const this_node = theContext()->getNode();
+
+  vtAssert(
+    dest_node == this_node,
+    fmt::format(
+      "Attempting to invoke handler on node:{} instead of node:{}!\n", this_node,
+      dest_node
+    )
+  );
+
+  util::NotCopyable<Type>* result;
+
+  runnable::makeRunnableVoid(false, uninitialized_handler, dest_node)
+    .withExplicitTask([&] {
+      auto&& ret = runnable::invoke<Type, f>(get(proxy), std::forward<Args>(args)...);
+      *result = std::move(ret);
+    })
+    .run();
+
+  return std::move(*result);
 }