freebsd-dev/contrib/csup/fixups.c

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2006-03-03 04:11:29 +00:00
/*-
* Copyright (c) 2006, Maxime Henrion <mux@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <assert.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include "fixups.h"
#include "misc.h"
#include "queue.h"
/*
* A synchronized queue to implement fixups. The updater thread adds
* fixup requests to the queue with fixups_put() when a checksum
* mismatch error occured. It then calls fixups_close() when he's
* done requesting fixups. The detailer thread gets the fixups with
* fixups_get() and then send the requests to the server.
*
* The queue is synchronized with a mutex and a condition variable.
*/
struct fixups {
pthread_mutex_t lock;
pthread_cond_t cond;
STAILQ_HEAD(, fixup) fixupq;
struct fixup *cur;
size_t size;
int closed;
};
static void fixups_lock(struct fixups *);
static void fixups_unlock(struct fixups *);
static struct fixup *fixup_new(struct coll *, const char *);
static void fixup_free(struct fixup *);
static void
fixups_lock(struct fixups *f)
{
int error;
error = pthread_mutex_lock(&f->lock);
assert(!error);
}
static void
fixups_unlock(struct fixups *f)
{
int error;
error = pthread_mutex_unlock(&f->lock);
assert(!error);
}
static struct fixup *
fixup_new(struct coll *coll, const char *name)
{
struct fixup *fixup;
fixup = xmalloc(sizeof(struct fixup));
fixup->f_name = xstrdup(name);
fixup->f_coll = coll;
return (fixup);
}
static void
fixup_free(struct fixup *fixup)
{
free(fixup->f_name);
free(fixup);
}
/* Create a new fixup queue. */
struct fixups *
fixups_new(void)
{
struct fixups *f;
f = xmalloc(sizeof(struct fixups));
f->size = 0;
f->closed = 0;
f->cur = NULL;
STAILQ_INIT(&f->fixupq);
pthread_mutex_init(&f->lock, NULL);
pthread_cond_init(&f->cond, NULL);
return (f);
}
/* Add a fixup request to the queue. */
void
fixups_put(struct fixups *f, struct coll *coll, const char *name)
{
struct fixup *fixup;
int dosignal;
dosignal = 0;
fixup = fixup_new(coll, name);
fixups_lock(f);
assert(!f->closed);
STAILQ_INSERT_TAIL(&f->fixupq, fixup, f_link);
if (f->size++ == 0)
dosignal = 1;
fixups_unlock(f);
if (dosignal)
pthread_cond_signal(&f->cond);
}
/* Get a fixup request from the queue. */
struct fixup *
fixups_get(struct fixups *f)
{
struct fixup *fixup, *tofree;
fixups_lock(f);
while (f->size == 0 && !f->closed)
pthread_cond_wait(&f->cond, &f->lock);
if (f->closed) {
fixups_unlock(f);
return (NULL);
}
assert(f->size > 0);
fixup = STAILQ_FIRST(&f->fixupq);
tofree = f->cur;
f->cur = fixup;
STAILQ_REMOVE_HEAD(&f->fixupq, f_link);
f->size--;
fixups_unlock(f);
if (tofree != NULL)
fixup_free(tofree);
return (fixup);
}
/* Close the writing end of the queue. */
void
fixups_close(struct fixups *f)
{
int dosignal;
dosignal = 0;
fixups_lock(f);
if (f->size == 0 && !f->closed)
dosignal = 1;
f->closed = 1;
fixups_unlock(f);
if (dosignal)
pthread_cond_signal(&f->cond);
}
/* Free a fixups queue. */
void
fixups_free(struct fixups *f)
{
struct fixup *fixup, *fixup2;
assert(f->closed);
/*
* Free any fixup that has been left on the queue.
* This can happen if we have been aborted prematurely.
*/
fixup = STAILQ_FIRST(&f->fixupq);
while (fixup != NULL) {
fixup2 = STAILQ_NEXT(fixup, f_link);
fixup_free(fixup);
fixup = fixup2;
}
if (f->cur != NULL)
fixup_free(f->cur);
pthread_cond_destroy(&f->cond);
pthread_mutex_destroy(&f->lock);
free(f);
}