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1//===----- unique_function.h - moveable type-erasing function ---*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8///9/// unique_function works like std::function, but supports move-only callable10/// objects.11///12/// TODO: Use LLVM's unique_function (llvm/include/llvm/ADT/FunctionExtras.h),13/// which uses some extra inline storage to avoid heap allocations for14/// small objects. Using LLVM's unique_function will require first15/// porting some other utilities like PointerIntPair, PointerUnion, and16/// PointerLikeTypeTraits. (These are likely to be independently useful17/// in the orc runtime, so porting will have additional benefits).18///19//===----------------------------------------------------------------------===//20 21#ifndef ORC_RT_UNIQUE_FUNCTION_H22#define ORC_RT_UNIQUE_FUNCTION_H23 24#include <memory>25 26namespace orc_rt {27 28namespace unique_function_detail {29 30template <typename RetT, typename... ArgTs> class Callable {31public:32 virtual ~Callable() = default;33 virtual RetT call(ArgTs &&...Args) = 0;34};35 36template <typename CallableT, typename RetT, typename... ArgTs>37class CallableImpl : public Callable<RetT, ArgTs...> {38public:39 CallableImpl(CallableT &&Callable) : Callable(std::move(Callable)) {}40 RetT call(ArgTs &&...Args) override {41 return Callable(std::forward<ArgTs>(Args)...);42 }43 44private:45 CallableT Callable;46};47 48} // namespace unique_function_detail49 50template <typename FnT> class unique_function;51 52template <typename RetT, typename... ArgTs>53class unique_function<RetT(ArgTs...)> {54public:55 unique_function() = default;56 unique_function(std::nullptr_t) {}57 unique_function(unique_function &&) = default;58 unique_function(const unique_function &&) = delete;59 unique_function &operator=(unique_function &&) = default;60 unique_function &operator=(const unique_function &&) = delete;61 62 template <typename CallableT>63 unique_function(CallableT &&Callable)64 : C(std::make_unique<65 unique_function_detail::CallableImpl<CallableT, RetT, ArgTs...>>(66 std::forward<CallableT>(Callable))) {}67 68 RetT operator()(ArgTs... Params) {69 return C->call(std::forward<ArgTs>(Params)...);70 }71 72 explicit operator bool() const { return !!C; }73 74private:75 std::unique_ptr<unique_function_detail::Callable<RetT, ArgTs...>> C;76};77 78} // namespace orc_rt79 80#endif // ORC_RT_UNIQUE_FUNCTION_H81