chore: import upstream snapshot with attribution

cpp/include/ray/api/task_caller.h

@@ -0,0 +1,109 @@
+// Copyright 2020-2021 The Ray Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <ray/api/runtime_env.h>
+#include <ray/api/static_check.h>
+#include <ray/api/task_options.h>
+
+namespace ray {
+namespace internal {
+
+template <typename F>
+class TaskCaller {
+ public:
+  TaskCaller();
+
+  TaskCaller(RayRuntime *runtime, RemoteFunctionHolder remote_function_holder);
+
+  template <typename... Args>
+  ObjectRef<boost::callable_traits::return_type_t<F>> Remote(Args &&...args);
+
+  TaskCaller &SetName(std::string name) {
+    task_options_.name = std::move(name);
+    return *this;
+  }
+
+  TaskCaller &SetResources(std::unordered_map<std::string, double> resources) {
+    task_options_.resources = std::move(resources);
+    return *this;
+  }
+
+  TaskCaller &SetResource(std::string name, double value) {
+    task_options_.resources.emplace(std::move(name), value);
+    return *this;
+  }
+
+  TaskCaller &SetPlacementGroup(PlacementGroup group, int bundle_index) {
+    task_options_.group = group;
+    task_options_.bundle_index = bundle_index;
+    return *this;
+  }
+
+  TaskCaller &SetRuntimeEnv(const ray::RuntimeEnv &runtime_env) {
+    task_options_.serialized_runtime_env_info = runtime_env.SerializeToRuntimeEnvInfo();
+    return *this;
+  }
+
+ private:
+  RayRuntime *runtime_;
+  RemoteFunctionHolder remote_function_holder_{};
+  std::string function_name_;
+  std::vector<TaskArg> args_;
+  CallOptions task_options_;
+};
+
+// ---------- implementation ----------
+
+template <typename F>
+TaskCaller<F>::TaskCaller() {}
+
+template <typename F>
+TaskCaller<F>::TaskCaller(RayRuntime *runtime,
+                          RemoteFunctionHolder remote_function_holder)
+    : runtime_(runtime), remote_function_holder_(std::move(remote_function_holder)) {}
+
+template <typename F>
+template <typename... Args>
+ObjectRef<boost::callable_traits::return_type_t<F>> TaskCaller<F>::Remote(
+    Args &&...args) {
+  CheckTaskOptions(task_options_.resources);
+
+  if constexpr (is_x_lang_v<F>) {
+    using ArgsTuple = std::tuple<Args...>;
+    Arguments::WrapArgs<ArgsTuple>(remote_function_holder_.lang_type_,
+                                   &args_,
+                                   std::make_index_sequence<sizeof...(Args)>{},
+                                   std::forward<Args>(args)...);
+  } else {
+    StaticCheck<F, Args...>();
+    using ArgsTuple = RemoveReference_t<boost::callable_traits::args_t<F>>;
+    Arguments::WrapArgs<ArgsTuple>(remote_function_holder_.lang_type_,
+                                   &args_,
+                                   std::make_index_sequence<sizeof...(Args)>{},
+                                   std::forward<Args>(args)...);
+  }
+
+  auto returned_object_id = runtime_->Call(remote_function_holder_, args_, task_options_);
+  using ReturnType = boost::callable_traits::return_type_t<F>;
+  auto return_ref = ObjectRef<ReturnType>(returned_object_id);
+  // The core worker will add an initial ref to each return ID to keep it in
+  // scope. Now that we've created the frontend ObjectRef, remove this initial
+  // ref.
+  runtime_->RemoveLocalReference(returned_object_id);
+  return return_ref;
+}
+}  // namespace internal
+}  // namespace ray