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// Copyright 2022 The Pigweed 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
//
// https://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 <tuple>
namespace pw::sync::internal {
// BorrowableStorage stores an object and associated lock. Both objects are
// constructed in-place.
template <typename ObjectType, typename Lock>
class BorrowableStorage {
protected:
// Construct the object in-place using a list of arguments.
template <typename... Args>
constexpr explicit BorrowableStorage(std::in_place_t, Args&&... args)
: object_{std::forward<Args>(args)...}, lock_{} {}
// Construct the object and lock in-place using the provided parameters.
template <typename... ObjectArgs, typename... LockArgs>
constexpr BorrowableStorage(std::tuple<ObjectArgs...>&& object_args,
std::tuple<LockArgs...>&& lock_args)
: object_{std::make_from_tuple<ObjectType>(
std::forward<std::tuple<ObjectArgs...>>(object_args))},
lock_{std::make_from_tuple<Lock>(
std::forward<std::tuple<LockArgs...>>(lock_args))} {}
// Construct the object and lock in-place using the provided factories.
template <typename ObjectConstructor,
typename LockConstructor,
typename = std::enable_if_t<
std::is_invocable_r_v<ObjectType&&, ObjectConstructor>>,
typename = std::enable_if_t<
std::is_invocable_r_v<Lock&&, LockConstructor>>>
constexpr BorrowableStorage(const ObjectConstructor& object_ctor,
const LockConstructor& lock_ctor)
: object_{object_ctor()}, lock_{lock_ctor()} {}
template <typename ObjectConstructor,
typename LockConstructor,
typename = std::enable_if_t<
std::is_invocable_r_v<ObjectType&&, ObjectConstructor>>,
typename = std::enable_if_t<
std::is_invocable_r_v<Lock&&, LockConstructor>>>
constexpr BorrowableStorage(ObjectConstructor& object_ctor,
const LockConstructor& lock_ctor)
: object_{object_ctor()}, lock_{lock_ctor()} {}
template <typename ObjectConstructor,
typename LockConstructor,
typename = std::enable_if_t<
std::is_invocable_r_v<ObjectType&&, ObjectConstructor>>,
typename = std::enable_if_t<
std::is_invocable_r_v<Lock&&, LockConstructor>>>
constexpr BorrowableStorage(const ObjectConstructor& object_ctor,
LockConstructor& lock_ctor)
: object_{object_ctor()}, lock_{lock_ctor()} {}
template <typename ObjectConstructor,
typename LockConstructor,
typename = std::enable_if_t<
std::is_invocable_r_v<ObjectType&&, ObjectConstructor>>,
typename = std::enable_if_t<
std::is_invocable_r_v<Lock&&, LockConstructor>>>
constexpr BorrowableStorage(ObjectConstructor& object_ctor,
LockConstructor& lock_ctor)
: object_{object_ctor()}, lock_{lock_ctor()} {}
ObjectType object_;
Lock lock_;
};
template <typename T>
T DefaultConstruct() {
return T();
}
} // namespace pw::sync::internal
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