path: root/src/common/mutex.h

/**
 * This file is part of Hercules.
 * http://herc.ws - http://github.com/HerculesWS/Hercules
 *
 * Copyright (C) 2012-2020 Hercules Dev Team
 * Copyright (C) rAthena Project (www.rathena.org)
 *
 * Hercules is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef COMMON_MUTEX_H
#define COMMON_MUTEX_H

#include "common/hercules.h"

/** @file
 * Mutex and conditional variables implementation for Hercules.
 */

/* Opaque types */

struct mutex_data; ///< Mutex
struct cond_data;  ///< Conditional variable

/* Interface */

/// The mutex interface.
struct mutex_interface {
	/**
	 * Creates a mutex.
	 *
	 * @return The created mutex.
	 */
	struct mutex_data *(*create) (void);

	/**
	 * Destroys a mutex.
	 *
	 * @param m the mutex to destroy.
	 */
	void (*destroy) (struct mutex_data *m);

	/**
	 * Gets a lock.
	 *
	 * This function blocks until the lock can be acquired.
	 *
	 * @param m The mutex to lock.
	 */
	void (*lock) (struct mutex_data *m);

	/**
	 * Tries to get a lock.
	 *
	 * This function returns immediately.
	 *
	 * @param m The mutex to try to lock.
	 * @return success status.
	 * @retval true if the lock was acquired.
	 * @retval false if the mutex couldn't be locked.
	 */
	bool (*trylock) (struct mutex_data *m);

	/**
	 * Unlocks a mutex.
	 *
	 * @param m The mutex to unlock.
	 */
	void (*unlock) (struct mutex_data *m);

	/**
	 * Creates a conditional variable.
	 *
	 * @return the created conditional variable.
	 */
	struct cond_data *(*cond_create) (void);

	/**
	 * Destroys a conditional variable.
	 *
	 * @param c the conditional variable to destroy.
	 */
	void (*cond_destroy) (struct cond_data *c);

	/**
	 * Waits Until state is signaled.
	 *
	 * @param c             The condition var to wait for signaled state.
	 * @param m             The mutex used for synchronization.
	 * @param timeout_ticks Timeout in ticks (-1 = INFINITE)
	 */
	void (*cond_wait) (struct cond_data *c, struct mutex_data *m, sysint timeout_ticks);

	/**
	 * Sets the given condition var to signaled state.
	 *
	 * @remark
	 *   Only one waiter gets notified.
	 *
	 * @param c Condition var to set in signaled state.
	 */
	void (*cond_signal) (struct cond_data *c);

	/**
	 * Sets notifies all waiting threads thats signaled.
	 *
	 * @remark
	 *   All Waiters getting notified.
	 *
	 * @param c Condition var to set in signaled state.
	 */
	void (*cond_broadcast) (struct cond_data *c);
};

#ifdef HERCULES_CORE
void mutex_defaults(void);
#endif // HERCULES_CORE

HPShared struct mutex_interface *mutex; ///< Pointer to the mutex interface.

#endif /* COMMON_MUTEX_H */