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/*
* Copyright (c) 2021, kleines Filmröllchen <malu.bertsch@gmail.com>.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Function.h>
#include <LibThreading/Mutex.h>
#include <pthread.h>
#include <sys/cdefs.h>
#include <sys/types.h>
namespace Threading {
// A signaling condition variable that wraps over the pthread_cond_* APIs.
class ConditionVariable {
friend class Mutex;
public:
ConditionVariable(Mutex& to_wait_on)
: m_to_wait_on(to_wait_on)
{
auto result = pthread_cond_init(&m_condition, nullptr);
VERIFY(result == 0);
}
ALWAYS_INLINE ~ConditionVariable()
{
auto result = pthread_cond_destroy(&m_condition);
VERIFY(result == 0);
}
// As with pthread APIs, the mutex must be locked or undefined behavior ensues.
ALWAYS_INLINE void wait()
{
auto result = pthread_cond_wait(&m_condition, &m_to_wait_on.m_mutex);
VERIFY(result == 0);
}
ALWAYS_INLINE void wait_while(Function<bool()> condition)
{
while (condition())
wait();
}
// Release at least one of the threads waiting on this variable.
ALWAYS_INLINE void signal()
{
auto result = pthread_cond_signal(&m_condition);
VERIFY(result == 0);
}
// Release all of the threads waiting on this variable.
ALWAYS_INLINE void broadcast()
{
auto result = pthread_cond_broadcast(&m_condition);
VERIFY(result == 0);
}
private:
pthread_cond_t m_condition;
Mutex& m_to_wait_on;
};
}
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