empserver/include/empthread.h
Markus Armbruster 060df4ec8f Document Empire's thread abstraction. Minor cleanups:
(empth_init): Change first parameter to void **.
(empth_sleep): Change parameter to time_t.
2005-06-25 16:37:59 +00:00

237 lines
6.6 KiB
C

/*
* Empire - A multi-player, client/server Internet based war game.
* Copyright (C) 1986-2005, Dave Pare, Jeff Bailey, Thomas Ruschak,
* Ken Stevens, Steve McClure
*
* This program 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* ---
*
* See the "LEGAL", "LICENSE", "CREDITS" and "README" files for all the
* related information and legal notices. It is expected that any 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
*/
/*
* 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 with the highest priority. Priorities
* are static. Empire code relies on these properties heavily. The
* most common form of yielding the processor is sleeping for some
* event to happen.
*/
#ifndef _EMTHREAD_H_
#define _EMTHREAD_H_
#include "misc.h"
#if defined(_WIN32)
#undef _EMPTH_LWP
#undef _EMPTH_POSIX
#define _EMPTH_WIN32
#endif
#ifdef _EMPTH_LWP
#include "lwp.h"
/* Abstract data types */
/* empth_t * represents a thread. */
typedef struct lwpProc empth_t;
/* empth_sem_t * represents a semaphore */
typedef struct lwpSem empth_sem_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
#ifdef __linux__
#define _MIT_POSIX_THREADS 1
#endif
#include <pthread.h>
#define EMPTH_FD_READ 0x1
#define EMPTH_FD_WRITE 0x2
#define EMPTH_PRINT 0x1
#define EMPTH_STACKCHECK 0x2
#define EMPTH_KILLED 1
typedef struct {
char *name; /* thread name */
char *desc; /* description */
void *ud; /* user data */
int state; /* my state */
void (*ep)(void *); /* entry point */
pthread_t id; /* thread id */
} empth_t;
typedef struct {
pthread_mutex_t mtx_update; /* use it to update count */
int count;
char name[80];
pthread_mutex_t mtx_sem;
pthread_cond_t cnd_sem;
} empth_sem_t;
#endif /* _EMPTH_POSIX */
/* DEC has slightly different names for whatever reason... */
#ifdef _DECTHREADS_
#define pthread_key_create pthread_keycreate
#define pthread_attr_init pthread_attr_create
#define pthread_attr_destroy pthread_attr_delete
#endif
#if defined(_EMPTH_WIN32)
/* 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_t empth_t;
typedef struct loc_Sem_t empth_sem_t;
void empth_request_shutdown(void);
#endif /* _EMPTH_WIN32 */
/*
* 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.
* PRIO is the scheduling priority.
* ENTRY is the entry point. It will be called with argument UD.
* Thread stack is at least SIZE bytes.
* FLAGS should be the same as were passed to empth_init(), or zero.
* NAME is the threads name, and DESC its description. These are 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.
* Return the thread, or NULL on error.
*/
empth_t *empth_create(int prio, void (*entry)(void *),
int size, int flags, char *name, char *desc, void *ud);
/*
* Return the current thread.
*/
empth_t *empth_self(void);
/*
* Terminate the current thread.
* Never returns.
*/
void empth_exit(void);
/*
* Yield the processor.
*/
void empth_yield(void);
/*
* Terminate THREAD.
* THREAD will not be scheduled again. Instead, it will terminate as
* if it executed empth_exit(). It is unspecified when exactly that
* happens.
* THREAD must not be the current thread.
*/
void empth_terminate(empth_t *thread);
/*
* 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.
* Note: Currently, Empire sleeps only on network I/O, i.e. FD is a
* socket. Implementations should not rely on that.
*/
void empth_select(int fd, int flags);
/*
* Awaken THREAD if it is sleeping in empth_select().
* Note: This must not awaken threads sleeping in other functions.
*/
void empth_wakeup(empth_t *thread);
/*
* Put current thread to sleep until the time is UNTIL.
* May sleep somehwat longer, but never shorter.
*/
void empth_sleep(time_t until);
/*
* Create a semaphore.
* NAME is its name, it is used for debugging.
* COUNT is the initial count value of the semaphore, it must not be
* negative.
* Return the semaphore, or NULL on error.
*/
empth_sem_t *empth_sem_create(char *name, int count);
/*
* Signal SEM.
* Increase SEM's count. If threads are sleeping on it, wake up
* exactly one of them. If that thread has a higher priority, yield
* the processor.
* This semaphore operation is often called `down' or `V' otherwhere.
*/
void empth_sem_signal(empth_sem_t *sem);
/*
* Wait for SEM.
* If SEM has a zero count, put current thread to sleep until
* empth_sem_signal() awakens it. SEM will have non-zero value then.
* Decrement SEM's count.
* This semaphore operation is often called `up' or `P' otherwhere.
*/
void empth_sem_wait(empth_sem_t *sem);
/* Internal function, not part of the thread abstraction */
void empth_alarm(int);
#endif