/*
* Empire - A multi-player, client/server Internet based war game.
* Copyright (C) 1986-2021, Dave Pare, Jeff Bailey, Thomas Ruschak,
* Ken Stevens, Steve McClure, Markus Armbruster
*
* Empire 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 .
*
* ---
*
* See files README, COPYING and CREDITS in the root of the source
* tree for related information and legal notices. It is expected
* that future projects/authors will amend these files as needed.
*
* ---
*
* empthread.h: Definitions for Empire threading
*
* Known contributors to this file:
* Sasha Mikheev
* Doug Hay, 1998
* Steve McClure, 1998
* Markus Armbruster, 2005-2012
* Ron Koenderink, 2005-2009
*/
/*
* This header defines Empire's abstract thread interface. There are
* several concrete implementations.
*
* Empire threads are non-preemptive, i.e. they run until they
* voluntarily yield the processor. The thread scheduler then picks
* one of the runnable threads. The most common form of yielding the
* processor is sleeping for some event to happen.
*/
#ifndef EMPTHREAD_H
#define EMPTHREAD_H
#include
#include
#ifdef EMPTH_LWP
#include "lwp.h"
/* Abstract data types */
/* A thread. */
typedef struct lwpProc empth_t;
/* A read-write lock, perferring writers */
typedef struct lwp_rwlock empth_rwlock_t;
/* Flags for empth_select(): whether to sleep on input or output */
#define EMPTH_FD_READ LWP_FD_READ
#define EMPTH_FD_WRITE LWP_FD_WRITE
/* Flags for empth_init() and empth_create() */
/* Request debug prints */
#define EMPTH_PRINT LWP_PRINT
/* Request stack checking */
#define EMPTH_STACKCHECK LWP_STACKCHECK
#endif /* EMPTH_LWP */
#ifdef EMPTH_POSIX
#define EMPTH_FD_READ 0x1
#define EMPTH_FD_WRITE 0x2
#define EMPTH_PRINT 0x1
#define EMPTH_STACKCHECK 0x2
typedef struct empth_t empth_t;
typedef struct empth_rwlock_t empth_rwlock_t;
#endif /* EMPTH_POSIX */
#ifdef EMPTH_W32
/* The Windows NT Threads */
#define EMPTH_FD_READ 0x1
#define EMPTH_FD_WRITE 0x2
#define EMPTH_PRINT 0x1
#define EMPTH_STACKCHECK 0x2
typedef struct loc_Thread empth_t;
typedef struct loc_RWLock empth_rwlock_t;
void empth_request_shutdown(void);
#endif /* EMPTH_W32 */
/*
* Initialize thread package.
* @ctx points to a thread context variable; see empth_create().
* @flags request optional features.
* Should return 0 on success, -1 on error, but currently always
* returns 0.
*/
int empth_init(void **ctx, int flags);
/*
* Create a new thread.
* @entry is the entry point. It will be called with argument @ud.
* If it returns, the thread terminates as if it called empth_exit().
* Thread stack is at least @size bytes.
* @flags should be the same as were passed to empth_init(), or zero.
* @name is the thread's name, it is used for logging and debugging.
* @ud is the value to pass to @entry. It is also assigned to the
* context variable defined with empth_init() whenever the thread gets
* scheduled.
* Yield the processor.
* Return the thread, or NULL on error.
*/
empth_t *empth_create(void (*entry)(void *),
int size, int flags, char *name, void *ud);
/*
* Return the current thread, NULL before empth_init().
* This is the only function that may be called before empth_init().
*/
empth_t *empth_self(void);
/*
* Return @thread's name.
*/
char *empth_name(empth_t *thread);
/*
* Set @thread's name to @name.
*/
void empth_set_name(empth_t *thread, char *name);
/*
* Terminate the current thread.
* The current thread should not be the thread that executed main().
* If it is, implementations may terminate the process rather than the
* thread.
* Never returns.
*/
void empth_exit(void);
/*
* Yield the processor.
*/
void empth_yield(void);
/*
* Put current thread to sleep until file descriptor @fd is ready for I/O.
* If @flags & EMPTH_FD_READ, wake up if @fd is ready for input.
* If @flags & EMPTH_FD_WRITE, wake up if @fd is ready for output.
* At most one thread may sleep on the same file descriptor.
* @timeout, if non-null, limits the sleep time.
* Return one when the @fd is ready, zero on timeout or early wakeup by
* empth_wakeup(), -1 on error with errno set.
* Note: Currently, Empire sleeps only on network I/O, i.e. @fd is a
* socket. Implementations should not rely on that.
*/
int empth_select(int fd, int flags, struct timeval *timeout);
/*
* Awaken @thread if it is sleeping in empth_select() or empth_sleep().
* This does not awaken threads sleeping in other functions.
* Does not yield the processor.
*/
void empth_wakeup(empth_t *thread);
/*
* Put current thread to sleep until the time is @until.
* Return 0 if it slept until that time.
* Return -1 if woken up early, by empth_wakeup().
*/
int empth_sleep(time_t until);
/*
* Put current thread to sleep until SIGHUP, SIGINT or SIGTERM is received.
* Return the signal number.
*/
int empth_wait_for_signal(void);
/*
* Create a read-write lock.
* @name is its name, it is used for debugging.
* Return the read-write lock, or NULL on error.
*/
empth_rwlock_t *empth_rwlock_create(char *name);
/*
* Destroy @rwlock.
*/
void empth_rwlock_destroy(empth_rwlock_t *rwlock);
/*
* Lock @rwlock for writing.
* A read-write lock can be locked for writing only when it is
* unlocked. If this is not the case, put the current thread to sleep
* until it is.
*/
void empth_rwlock_wrlock(empth_rwlock_t *rwlock);
/*
* Lock @rwlock for reading.
* A read-write lock can be locked for reading only when it is not
* locked for writing, and no other thread is attempting to lock it
* for writing. If this is not the case, put the current thread to
* sleep until it is.
*/
void empth_rwlock_rdlock(empth_rwlock_t *rwlock);
/*
* Unlock read-write lock @rwlock.
* The current thread must hold @rwlock.
* Wake up threads that can now lock it.
*/
void empth_rwlock_unlock(empth_rwlock_t *rwlock);
/*
* Stuff for implementations, not for clients.
*/
void empth_init_signals(void);
#endif