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/**
* Copyright (C) 2019-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
namespace mongo {
// BasicLockableAdapter allows non-template functions to take any lockable type. This can be useful
// when you have a custom lockable type and don't want to make the lockable parameter concrete for a
// function but can't make the function use a template parameter for the lock type.
//
// This type should NOT be used to store a lockable type!
//
// Example:
// void wait(BasicLockableAdapter lock) {
// stdx::lock_guard lg(lock);
// }
//
// mongo::ResourceMutex mut;
// wait(mut);
class BasicLockableAdapter {
public:
template <typename T>
BasicLockableAdapter(T& lock) : _underlyingLock(&lock), _vtable(&forT<std::decay_t<T>>) {}
void lock() {
_vtable->lock(_underlyingLock);
}
void unlock() {
_vtable->unlock(_underlyingLock);
}
private:
struct VTable {
void (*lock)(void*);
void (*unlock)(void*);
};
template <typename T>
static inline VTable forT = VTable{+[](void* t) { static_cast<T*>(t)->lock(); },
+[](void* t) { static_cast<T*>(t)->unlock(); }};
void* _underlyingLock;
const VTable* _vtable;
};
} // namespace mongo
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