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//===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===// | |
// | |
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | |
// See https://llvm.org/LICENSE.txt for license information. | |
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | |
// | |
//===----------------------------------------------------------------------===// | |
// | |
// This file contains some templates that are useful if you are working with the | |
// STL at all. | |
// | |
// No library is required when using these functions. | |
// | |
//===----------------------------------------------------------------------===// | |
// c10: modified from llvm::function_ref | |
// c10: added more SFINAE to enable use in overloaded functions | |
namespace c10 { | |
/// An efficient, type-erasing, non-owning reference to a callable. This is | |
/// intended for use as the type of a function parameter that is not used | |
/// after the function in question returns. | |
/// | |
/// This class does not own the callable, so it is not in general safe to store | |
/// a function_ref. | |
template <typename Fn> | |
class function_ref; | |
template <typename Ret, typename... Params> | |
class function_ref<Ret(Params...)> { | |
Ret (*callback)(intptr_t callable, Params... params) = nullptr; | |
intptr_t callable{}; | |
template <typename Callable> | |
static Ret callback_fn(intptr_t callable, Params... params) { | |
return (*reinterpret_cast<Callable*>(callable))( | |
std::forward<Params>(params)...); | |
} | |
public: | |
function_ref() = default; | |
function_ref(std::nullptr_t) {} | |
template <typename Callable> | |
function_ref( | |
// NOLINTNEXTLINE(cppcoreguidelines-missing-std-forward) | |
Callable&& callable, | |
std::enable_if_t< | |
!std::is_same_v<std::remove_reference_t<Callable>, function_ref>>* = | |
nullptr, | |
std::enable_if_t<std::is_convertible_v< | |
typename std::invoke_result_t<Callable, Params...>, | |
Ret>>* = nullptr) | |
: callback(callback_fn<std::remove_reference_t<Callable>>), | |
callable(reinterpret_cast<intptr_t>(&callable)) {} | |
Ret operator()(Params... params) const { | |
return callback(callable, std::forward<Params>(params)...); | |
} | |
operator bool() const { | |
return callback; | |
} | |
}; | |
} // namespace c10 | |