ladybird/Kernel/Lock.h
2020-02-16 01:50:32 +01:00

102 lines
2.8 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/Assertions.h>
#include <AK/Atomic.h>
#include <AK/Types.h>
#include <Kernel/Arch/i386/CPU.h>
#include <Kernel/Forward.h>
#include <Kernel/WaitQueue.h>
namespace Kernel {
extern Thread* current;
class Lock {
public:
Lock(const char* name = nullptr)
: m_name(name)
{
}
~Lock() {}
void lock();
void unlock();
bool force_unlock_if_locked();
bool is_locked() const { return m_holder; }
const char* name() const { return m_name; }
private:
Atomic<bool> m_lock { false };
u32 m_level { 0 };
Thread* m_holder { nullptr };
const char* m_name { nullptr };
WaitQueue m_queue;
};
class Locker {
public:
[[gnu::always_inline]] inline explicit Locker(Lock& l)
: m_lock(l)
{
lock();
}
[[gnu::always_inline]] inline ~Locker() { unlock(); }
[[gnu::always_inline]] inline void unlock() { m_lock.unlock(); }
[[gnu::always_inline]] inline void lock() { m_lock.lock(); }
private:
Lock& m_lock;
};
#define LOCKER(lock) Locker locker(lock)
template<typename T>
class Lockable {
public:
Lockable() {}
Lockable(T&& resource)
: m_resource(move(resource))
{
}
Lock& lock() { return m_lock; }
T& resource() { return m_resource; }
T lock_and_copy()
{
LOCKER(m_lock);
return m_resource;
}
private:
T m_resource;
Lock m_lock;
};
}