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/* games-scores-backend.c
*
* Copyright (C) 2005 Callum McKenzie
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <config.h>
#include <glib.h>
#include <glib-object.h>
#include <string.h>
#include <stdlib.h>
#include "games-score.h"
#include "games-scores.h"
#include "games-scores-backend.h"
#ifdef ENABLE_SETGID
#include "games-setgid-io.h"
#endif
struct _GamesScoresBackendPrivate {
GamesScoreStyle style;
time_t timestamp;
gchar *filename;
gint fd;
};
G_DEFINE_TYPE (GamesScoresBackend, games_scores_backend, G_TYPE_OBJECT);
static void
games_scores_backend_finalize (GObject *object)
{
GamesScoresBackend *backend = GAMES_SCORES_BACKEND (object);
GamesScoresBackendPrivate *priv = backend->priv;
g_free (priv->filename);
/* FIXME: more to do? */
G_OBJECT_CLASS (games_scores_backend_parent_class)->finalize (object);
}
static void
games_scores_backend_class_init (GamesScoresBackendClass * klass)
{
GObjectClass *oclass = G_OBJECT_CLASS (klass);
g_type_class_add_private (klass, sizeof (GamesScoresBackendPrivate));
oclass->finalize = games_scores_backend_finalize;
}
static void
games_scores_backend_init (GamesScoresBackend * backend)
{
backend->priv = G_TYPE_INSTANCE_GET_PRIVATE (backend,
GAMES_TYPE_SCORES_BACKEND,
GamesScoresBackendPrivate);
}
GamesScoresBackend *
games_scores_backend_new (GamesScoreStyle style,
char *base_name,
char *name)
{
GamesScoresBackend *backend;
gchar *fullname;
backend = GAMES_SCORES_BACKEND (g_object_new (GAMES_TYPE_SCORES_BACKEND,
NULL));
if (name[0] == '\0') /* Name is "" */
fullname = g_strjoin (".", base_name, "scores", NULL);
else
fullname = g_strjoin (".", base_name, name, "scores", NULL);
backend->priv->timestamp = 0;
backend->priv->style = style;
backend->scores_list = NULL;
backend->priv->filename = g_build_filename (SCOREDIR,
fullname, NULL);
g_free (fullname);
backend->priv->fd = -1;
return backend;
}
#ifdef ENABLE_SETGID
/* Get a lock on the scores file. Block until it is available.
* This also supplies the file descriptor we need. The return value
* is whether we were succesful or not. */
static gboolean
games_scores_backend_get_lock (GamesScoresBackend * self)
{
gint error;
if (self->priv->fd != -1) {
/* Assume we already have the lock and rewind the file to
* the beginning. */
setgid_io_seek (self->priv->fd, 0, SEEK_SET);
return TRUE; /* Assume we already have the lock. */
}
self->priv->fd = setgid_io_open (self->priv->filename, O_RDWR);
if (self->priv->fd == -1) {
return FALSE;
}
error = setgid_io_lock (self->priv->fd);
if (error == -1) {
setgid_io_close (self->priv->fd);
self->priv->fd = -1;
return FALSE;
}
return TRUE;
}
/* Release the lock on the scores file and dispose of the fd. */
/* We ignore errors, there is nothing we can do about them. */
static void
games_scores_backend_release_lock (GamesScoresBackend * self)
{
/* We don't have a lock, ignore this call. */
if (self->priv->fd == -1)
return;
setgid_io_unlock (self->priv->fd);
setgid_io_close (self->priv->fd);
self->priv->fd = -1;
}
#endif /* ENABLE_SETGID */
/* You can alter the list returned by this function, but you must
* make sure you set it again with the _set_scores method or discard it
* with with the _discard_scores method. Otherwise deadlocks will ensue. */
GList *
games_scores_backend_get_scores (GamesScoresBackend * self)
{
#ifdef ENABLE_SETGID
gchar *buffer;
gchar *eol;
gchar *scorestr;
gchar *timestr;
gchar *namestr;
GamesScore *newscore;
struct stat info;
int error;
ssize_t length, target;
GList *t;
/* Check for a change in the scores file and update if necessary. */
error = setgid_io_stat (self->priv->filename, &info);
/* If an error occurs then we give up on the file and return NULL. */
if (error != 0)
return NULL;
if ((info.st_mtime > self->priv->timestamp) || (self->scores_list == NULL)) {
self->priv->timestamp = info.st_mtime;
/* Dump the old list of scores. */
t = self->scores_list;
while (t != NULL) {
games_score_destroy ((GamesScore *) t->data);
t = g_list_next (t);
}
g_list_free (self->scores_list);
self->scores_list = NULL;
/* Lock the file and get the list. */
if (!games_scores_backend_get_lock (self))
return NULL;
buffer = g_malloc (info.st_size + 1);
if (buffer == NULL) {
games_scores_backend_release_lock (self);
return NULL;
}
target = info.st_size;
length = 0;
do {
target -= length;
length = setgid_io_read (self->priv->fd, buffer, info.st_size);
if (length == -1) {
games_scores_backend_release_lock (self);
g_free (buffer);
return NULL;
}
} while (length < target);
buffer[info.st_size] = '\0';
/* FIXME: These details should be in a sub-class. */
/* Parse the list. We start by breaking it into lines. */
/* Since the buffer is null-terminated
* we can do the string stuff reasonably safely. */
eol = strchr (buffer, '\n');
scorestr = buffer;
while (eol != NULL) {
*eol++ = '\0';
timestr = strchr (scorestr, ' ');
if (timestr == NULL)
break;
*timestr++ = '\0';
namestr = strchr (timestr, ' ');
if (namestr == NULL)
break;
*namestr++ = '\0';
/* At this point we have three strings, all null terminated. All
* part of the original buffer. */
newscore = games_score_new ();
newscore->name = g_strdup (namestr);
newscore->time = g_ascii_strtoull (timestr, NULL, 10);
switch (self->priv->style) {
case GAMES_SCORES_STYLE_PLAIN_DESCENDING:
case GAMES_SCORES_STYLE_PLAIN_ASCENDING:
newscore->value.plain = g_ascii_strtod (scorestr, NULL);
break;
case GAMES_SCORES_STYLE_TIME_DESCENDING:
case GAMES_SCORES_STYLE_TIME_ASCENDING:
newscore->value.time_double = g_ascii_strtod (scorestr, NULL);
break;
default:
g_assert_not_reached ();
}
self->scores_list = g_list_append (self->scores_list, newscore);
/* Setup again for the next time around. */
scorestr = eol;
eol = strchr (eol, '\n');
}
g_free (buffer);
}
/* FIXME: Sort the scores! We shouldn't rely on the file being sorted. */
return self->scores_list;
#else
return NULL;
#endif /* ENABLE_SETGID */
}
gboolean
games_scores_backend_set_scores (GamesScoresBackend * self, GList * list)
{
#ifdef ENABLE_SETGID
GList *s;
GamesScore *d;
gchar *buffer;
gint output_length = 0;
gchar dtostrbuf[G_ASCII_DTOSTR_BUF_SIZE];
if (!games_scores_backend_get_lock (self))
return FALSE;
self->scores_list = list;
s = list;
while (s != NULL) {
gdouble rscore;
guint64 rtime;
gchar *rname;
d = (GamesScore *) s->data;
rscore = 0.0;
switch (self->priv->style) {
case GAMES_SCORES_STYLE_PLAIN_DESCENDING:
case GAMES_SCORES_STYLE_PLAIN_ASCENDING:
rscore = d->value.plain;
break;
case GAMES_SCORES_STYLE_TIME_DESCENDING:
case GAMES_SCORES_STYLE_TIME_ASCENDING:
rscore = d->value.time_double;
break;
default:
g_assert_not_reached ();
}
rtime = d->time;
rname = d->name;
buffer = g_strdup_printf ("%s %lld %s\n",
g_ascii_dtostr (dtostrbuf, sizeof (dtostrbuf),
rscore), rtime, rname);
setgid_io_write (self->priv->fd, buffer, strlen (buffer));
output_length += strlen (buffer);
/* Ignore any errors and blunder on. */
g_free (buffer);
s = g_list_next (s);
}
/* Remove any content in the file that hasn't yet been overwritten. */
setgid_io_truncate (self->priv->fd, output_length--);
/* Update the timestamp so we don't reread the scores unnecessarily. */
self->priv->timestamp = time (NULL);
games_scores_backend_release_lock (self);
return TRUE;
#else
return FALSE;
#endif /* ENABLE_SETGID */
}
void
games_scores_backend_discard_scores (GamesScoresBackend * self)
{
#ifdef ENABLE_SETGID
games_scores_backend_release_lock (self);
#endif
}
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