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serenity/Userland/Libraries/LibThreading/Lock.h
Andreas Kling c40780d404 LibThreading: Reimplement Lock in terms of pthread_mutex_t
This class was previously a spinlock that would call sys$donate()
to donate its timeslice to whichever thread was holding the lock.

Now that pthread_mutex_t has a fast path, let's implement Lock on top
of that instead and get rid of the last remaining user of sys$donate().
2021-07-05 23:30:15 +02:00

81 lines
1.3 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Assertions.h>
#include <AK/Types.h>
#include <pthread.h>
namespace Threading {
class Lock {
public:
Lock() { }
~Lock() { }
void lock();
void unlock();
private:
pthread_mutex_t m_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
};
class Locker {
public:
ALWAYS_INLINE explicit Locker(Lock& l)
: m_lock(l)
{
lock();
}
ALWAYS_INLINE ~Locker() { unlock(); }
ALWAYS_INLINE void unlock() { m_lock.unlock(); }
ALWAYS_INLINE void lock() { m_lock.lock(); }
private:
Lock& m_lock;
};
ALWAYS_INLINE void Lock::lock()
{
pthread_mutex_lock(&m_mutex);
}
inline void Lock::unlock()
{
pthread_mutex_unlock(&m_mutex);
}
template<typename T>
class Lockable {
public:
Lockable() { }
template<typename... Args>
Lockable(Args&&... args)
: m_resource(forward(args)...)
{
}
Lockable(T&& resource)
: m_resource(move(resource))
{
}
Lock& lock() { return m_lock; }
T& resource() { return m_resource; }
T lock_and_copy()
{
Locker locker(m_lock);
return m_resource;
}
private:
T m_resource;
Lock m_lock;
};
}