71 lines
2.0 KiB
C++
71 lines
2.0 KiB
C++
/*
|
|
* Copyright (c) Facebook, Inc. and its affiliates.
|
|
*
|
|
* 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 <cstdint>
|
|
#include <typeinfo>
|
|
|
|
#include <folly/detail/StaticSingletonManager.h>
|
|
|
|
namespace folly {
|
|
namespace detail {
|
|
|
|
class UniqueInstance {
|
|
public:
|
|
template <typename... Key, typename... Mapped>
|
|
FOLLY_EXPORT explicit UniqueInstance(
|
|
char const* tmpl,
|
|
tag_t<Key...>,
|
|
tag_t<Mapped...>) noexcept {
|
|
static Ptr const ptrs[] = {&typeid(Key)..., &typeid(Mapped)...};
|
|
auto& global = createGlobal<Value, tag_t<Tag, Key...>>();
|
|
enforce(tmpl, ptrs, sizeof...(Key), sizeof...(Mapped), global);
|
|
}
|
|
|
|
UniqueInstance(UniqueInstance const&) = delete;
|
|
UniqueInstance(UniqueInstance&&) = delete;
|
|
UniqueInstance& operator=(UniqueInstance const&) = delete;
|
|
UniqueInstance& operator=(UniqueInstance&&) = delete;
|
|
|
|
private:
|
|
struct Tag {};
|
|
|
|
using Ptr = std::type_info const*;
|
|
struct PtrRange {
|
|
Ptr const* b;
|
|
Ptr const* e;
|
|
};
|
|
struct Value {
|
|
char const* tmpl;
|
|
Ptr const* ptrs;
|
|
std::uint32_t key_size;
|
|
std::uint32_t mapped_size;
|
|
};
|
|
|
|
// Under Clang, this call signature shrinks the aligned and padded size of
|
|
// call-sites, as compared to a call signature taking Value or Value const&.
|
|
static void enforce(
|
|
char const* tmpl,
|
|
Ptr const* ptrs,
|
|
std::uint32_t key_size,
|
|
std::uint32_t mapped_size,
|
|
Value& global) noexcept;
|
|
};
|
|
|
|
} // namespace detail
|
|
} // namespace folly
|