Player threads may only sleep under certain conditions. In
particular, they must not sleep while a command is being aborted by
the update or shutdown.
io.c should not know about that. Yet io_output_all() does, because it
needs to give up when update or shutdown interrupt it. The function
was introduced in Empire 2, but it didn't give up then. Fixed in
commit a7fa7dee
, v4.2.22. The fix dragged unwanted knowledge of
command abortion into io.c.
To clean up this mess, io_output_all() has to go.
First user is io_write(). io_write() automatically flushes the queue.
In wait-mode, it calls io_output_all() when the queue is longer than
the bufsize, to attempt flushing the queue completely. In
no-wait-mode, it calls io_output() every bufsize bytes. Except the
test for that is screwy, so it actually misses some of the flush
conditions.
The automatic flush makes io_write() differ from io_gets(), which is
ugly. It wasn't present in BSD Empire 1.1. Remove it again, dropping
io_write()'s last argument.
Flush the queue in its callers pr_player() and upr_player() instead.
Provide new io_output_if_queue_long() for them. Requires new struct
iop member last_out to keep track of queue growth. pr_player() and
upr_player() call repeatedly until it makes no more progress. This
flushes a bit less eagerly in wait-mode, and a bit more eagerly in
non-wait mode.
Second user is recvclient(). It needs to flush the queue before
potentially sleeping in io_input(). Do that with a simple loop around
io_output(). No functional change there.
63 lines
2.1 KiB
C
63 lines
2.1 KiB
C
/*
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* Empire - A multi-player, client/server Internet based war game.
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* Copyright (C) 1986-2009, 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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* empio.h: Describes io pointers used in Empire
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*
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* Known contributors to this file:
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*
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*/
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#ifndef EMPIO_H
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#define EMPIO_H
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#include <sys/time.h>
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#define IO_READ 0x1
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#define IO_WRITE 0x2
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#define IO_EOF 0x10
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#define IO_ERROR 0x40
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#define IO_BUFSIZE 4096
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extern struct iop *io_open(int, int, int, struct timeval);
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extern void io_init(void);
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extern void io_close(struct iop *);
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extern int io_input(struct iop *, int);
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extern int io_inputwaiting(struct iop *);
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extern int io_outputwaiting(struct iop *);
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extern int io_output(struct iop *, int);
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extern int io_output_if_queue_long(struct iop *, int);
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extern int io_peek(struct iop *, char *, int);
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extern int io_read(struct iop *, char *, int);
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extern int io_write(struct iop *, char *, int);
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extern int io_gets(struct iop *, char *, int);
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extern int io_puts(struct iop *, char *);
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extern int io_shutdown(struct iop *, int);
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extern int io_error(struct iop *);
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extern int io_eof(struct iop *);
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extern int io_fileno(struct iop *);
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#endif
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