ladybird/Userland/Libraries/LibThreading/MutexProtected.h
kleines Filmröllchen 3d6e08156d LibThreading: Introduce MutexProtected generic synchronization primitive
MutexProtected mirrors the identically-named Kernel primitive and can be
used to synchronize access to any object that might not be thread safe
on its own. Synchronization is done with a simple mutex, so access to a
MutexProtected object is potentially blocking.

Mutex now has an internal nesting variable which is there to harden it
against lock-unlock ordering issues (e.g. double unlocking).
2022-01-23 15:21:10 +01:00

57 lines
1.2 KiB
C++

/*
* Copyright (c) 2022, kleines Filmröllchen <malu.bertsch@gmail.com>.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Concepts.h>
#include <AK/Noncopyable.h>
#include <LibThreading/Mutex.h>
namespace Threading {
template<typename T>
class MutexProtected {
AK_MAKE_NONCOPYABLE(MutexProtected);
AK_MAKE_NONMOVABLE(MutexProtected);
using ProtectedType = T;
public:
ALWAYS_INLINE MutexProtected() = default;
ALWAYS_INLINE MutexProtected(T&& value)
: m_value(move(value))
{
}
ALWAYS_INLINE explicit MutexProtected(T& value)
: m_value(value)
{
}
template<typename Callback>
decltype(auto) with_locked(Callback callback)
{
auto lock = this->lock();
// This allows users to get a copy, but if we don't allow references through &m_value, it's even more complex.
return callback(m_value);
}
template<VoidFunction<T> Callback>
void for_each_locked(Callback callback)
{
with_locked([&](auto& value) {
for (auto& item : value)
callback(item);
});
}
private:
[[nodiscard]] ALWAYS_INLINE MutexLocker lock() { return MutexLocker(m_lock); }
T m_value;
Mutex m_lock {};
};
}