271 lines
7.5 KiB
C
271 lines
7.5 KiB
C
/*
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* Empire - A multi-player, client/server Internet based war game.
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* Copyright (C) 1986-2007, Dave Pare, Jeff Bailey, Thomas Ruschak,
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* Ken Stevens, Steve McClure
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* ---
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*
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* See files README, COPYING and CREDITS in the root of the source
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* tree for related information and legal notices. It is expected
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* that future projects/authors will amend these files as needed.
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*
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* ---
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*
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* empthread.h: Definitions for Empire threading
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*
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* Known contributors to this file:
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* Sasha Mikheev
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* Doug Hay, 1998
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* Steve McClure, 1998
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* Markus Armbruster, 2005-2007
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*/
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/*
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* This header defines Empire's abstract thread interface. There are
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* several concrete implementations.
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*
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* Empire threads are non-preemptive, i.e. they run until they
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* voluntarily yield the processor. The thread scheduler then picks
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* one of the runnable threads with the highest priority. Priorities
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* are static. Empire code relies on these properties heavily. The
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* most common form of yielding the processor is sleeping for some
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* event to happen.
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*/
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#ifndef EMPTHREAD_H
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#define EMPTHREAD_H
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#include <time.h>
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/* thread priorities */
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enum {
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PP_MAIN = 7,
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PP_UPDATE = 6,
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PP_SHUTDOWN = 5,
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PP_SCHED = 4,
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PP_TIMESTAMP = 2,
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PP_PLAYER = 3,
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PP_ACCEPT = 3,
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PP_KILLIDLE = 2
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};
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#ifdef EMPTH_LWP
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#include "lwp.h"
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/* Abstract data types */
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/* empth_t * represents a thread. */
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typedef struct lwpProc empth_t;
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/* empth_sem_t * represents a semaphore */
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typedef struct lwpSem empth_sem_t;
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/* empth_rwlock_t * represents a read-write lock */
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typedef struct lwp_rwlock empth_rwlock_t;
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/* Flags for empth_select(): whether to sleep on input or output */
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#define EMPTH_FD_READ LWP_FD_READ
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#define EMPTH_FD_WRITE LWP_FD_WRITE
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/* Flags for empth_init() and empth_create() */
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/* Request debug prints */
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#define EMPTH_PRINT LWP_PRINT
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/* Request stack checking */
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#define EMPTH_STACKCHECK LWP_STACKCHECK
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#endif /* EMPTH_LWP */
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#ifdef EMPTH_POSIX
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#define EMPTH_FD_READ 0x1
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#define EMPTH_FD_WRITE 0x2
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#define EMPTH_PRINT 0x1
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#define EMPTH_STACKCHECK 0x2
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typedef struct empth_t empth_t;
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typedef struct empth_sem_t empth_sem_t;
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typedef struct empth_rwlock_t empth_rwlock_t;
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#endif /* EMPTH_POSIX */
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#ifdef EMPTH_W32
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/* The Windows NT Threads */
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#define EMPTH_FD_READ 0x1
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#define EMPTH_FD_WRITE 0x2
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#define EMPTH_PRINT 0x1
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#define EMPTH_STACKCHECK 0x2
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typedef struct loc_Thread empth_t;
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typedef struct loc_Sem empth_sem_t;
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typedef struct loc_RWLock empth_rwlock_t;
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void empth_request_shutdown(void);
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#endif /* EMPTH_W32 */
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/*
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* Initialize thread package.
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* CTX points to a thread context variable; see empth_create().
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* FLAGS request optional features.
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* Should return 0 on success, -1 on error, but currently always
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* returns 0.
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*/
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int empth_init(void **ctx, int flags);
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/*
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* Create a new thread.
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* PRIO is the scheduling priority.
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* ENTRY is the entry point. It will be called with argument UD.
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* Thread stack is at least SIZE bytes.
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* FLAGS should be the same as were passed to empth_init(), or zero.
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* NAME is the threads name, and DESC its description. These are used
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* for logging and debugging.
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* UD is the value to pass to ENTRY. It is also assigned to the
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* context variable defined with empth_init() whenever the thread gets
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* scheduled.
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* Yield the processor.
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* Return the thread, or NULL on error.
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*/
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empth_t *empth_create(int prio, void (*entry)(void *),
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int size, int flags, char *name, char *desc, void *ud);
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/*
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* Return the current thread.
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*/
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empth_t *empth_self(void);
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/*
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* Terminate the current thread.
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* The current thread should not be the thread that executed main().
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* If it is, implementations may terminate the process rather than the
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* thread.
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* Never returns.
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*/
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void empth_exit(void);
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/*
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* Yield the processor.
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*/
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void empth_yield(void);
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/*
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* Terminate THREAD.
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* THREAD will not be scheduled again. Instead, it will terminate as
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* if it executed empth_exit(). It is unspecified when exactly that
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* happens.
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* THREAD must not be the current thread.
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*/
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void empth_terminate(empth_t *thread);
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/*
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* Put current thread to sleep until file descriptor FD is ready for I/O.
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* If FLAGS & EMPTH_FD_READ, wake up if FD is ready for input.
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* If FLAGS & EMPTH_FD_WRITE, wake up if FD is ready for output.
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* At most one thread may sleep on the same file descriptor.
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* Note: Currently, Empire sleeps only on network I/O, i.e. FD is a
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* socket. Implementations should not rely on that.
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*/
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void empth_select(int fd, int flags);
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/*
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* Awaken THREAD if it is sleeping in empth_select().
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* Note: This must not awaken threads sleeping in other functions.
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*/
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void empth_wakeup(empth_t *thread);
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/*
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* Put current thread to sleep until the time is UNTIL.
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* May sleep somehwat longer, but never shorter.
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*/
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void empth_sleep(time_t until);
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/*
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* Wait for signal, return the signal number
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*/
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int empth_wait_for_signal(void);
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/*
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* Create a semaphore.
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* NAME is its name, it is used for debugging.
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* COUNT is the initial count value of the semaphore, it must not be
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* negative.
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* Return the semaphore, or NULL on error.
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*/
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empth_sem_t *empth_sem_create(char *name, int count);
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/*
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* Signal SEM.
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* Increase SEM's count. If threads are sleeping on it, wake up
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* exactly one of them. If that thread has a higher priority, yield
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* the processor.
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* This semaphore operation is often called `down' or `V' otherwhere.
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*/
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void empth_sem_signal(empth_sem_t *sem);
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/*
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* Wait for SEM.
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* If SEM has a zero count, put current thread to sleep until
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* empth_sem_signal() awakens it. SEM will have non-zero value then.
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* Decrement SEM's count.
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* This semaphore operation is often called `up' or `P' otherwhere.
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*/
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void empth_sem_wait(empth_sem_t *sem);
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/*
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* Create a read-write lock.
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* NAME is its name, it is used for debugging.
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* Return the reade-write lock, or NULL on error.
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*/
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empth_rwlock_t *empth_rwlock_create(char *name);
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/*
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* Destroy RWLOCK.
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*/
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void empth_rwlock_destroy(empth_rwlock_t *rwlock);
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/*
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* Lock RWLOCK for writing.
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* A read-write lock can be locked for writing only when it is
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* unlocked. If this is not the case, put the current thread to sleep
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* until it is.
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*/
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void empth_rwlock_wrlock(empth_rwlock_t *rwlock);
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/*
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* Lock RWLOCK for reading.
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* A read-write lock can be locked for reading only when it is not
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* locked for writing. If this is not the case, put the current
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* thread to sleep until it is. Must not starve writers, and may
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* sleep to avoid that.
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*/
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void empth_rwlock_rdlock(empth_rwlock_t *rwlock);
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/*
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* Unlock read-write lock RWLOCK.
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* The current thread must hold RWLOCK.
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* Wake up threads that can now lock it.
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*/
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void empth_rwlock_unlock(empth_rwlock_t *rwlock);
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/*
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* Stuff for implementations, not for clients.
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*/
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void empth_init_signals(void);
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#endif
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