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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-uid-cache.c: UID caching code. */
/*
* Authors:
* Dan Winship <danw@helixcode.com>
*
* Copyright 2000 Helix Code, Inc. (http://www.helixcode.com)
*
* 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
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include "camel-uid-cache.h"
static void free_uid (gpointer key, gpointer value, gpointer data);
static void maybe_write_uid (gpointer key, gpointer value, gpointer data);
/**
* camel_uid_cache_new:
* @filename: path to load the cache from
*
* Creates a new UID cache, initialized from @filename. If @filename
* doesn't already exist, the UID cache will be empty. Otherwise, if
* it does exist but can't be read, the function will return %NULL.
*
* Return value: a new UID cache, or %NULL
**/
CamelUIDCache *
camel_uid_cache_new (const char *filename)
{
CamelUIDCache *cache;
struct stat st;
char *buf, **uids;
int fd, i;
fd = open (filename, O_RDWR | O_CREAT, 0700);
if (fd == -1)
return NULL;
if (fstat (fd, &st) != 0) {
close (fd);
return NULL;
}
buf = g_malloc (st.st_size + 1);
if (read (fd, buf, st.st_size) == -1) {
close (fd);
g_free (buf);
return NULL;
}
buf[st.st_size] = '\0';
cache = g_new (CamelUIDCache, 1);
cache->fd = fd;
cache->level = 1;
cache->uids = g_hash_table_new (g_str_hash, g_str_equal);
uids = g_strsplit (buf, "\n", 0);
g_free (buf);
for (i = 0; uids[i]; i++) {
g_hash_table_insert (cache->uids, uids[i],
GINT_TO_POINTER (cache->level));
}
g_free (uids);
return cache;
}
/**
* camel_uid_cache_save:
* @cache: a CamelUIDCache
*
* Attempts to save @cache back to disk.
*
* Return value: success or failure
**/
gboolean
camel_uid_cache_save (CamelUIDCache *cache)
{
if (lseek (cache->fd, 0, SEEK_SET) != 0)
return FALSE;
g_hash_table_foreach (cache->uids, maybe_write_uid, cache);
return ftruncate (cache->fd, lseek (cache->fd, 0, SEEK_CUR)) == 0;
}
static void
maybe_write_uid (gpointer key, gpointer value, gpointer data)
{
CamelUIDCache *cache = data;
if (GPOINTER_TO_INT (value) == cache->level) {
write (cache->fd, key, strlen (key));
write (cache->fd, "\n", 1);
}
}
/**
* camel_uid_cache_destroy:
* @cache: a CamelUIDCache
*
* Destroys @cache and frees its data.
**/
void
camel_uid_cache_destroy (CamelUIDCache *cache)
{
g_hash_table_foreach (cache->uids, free_uid, NULL);
g_hash_table_destroy (cache->uids);
close (cache->fd);
g_free (cache);
}
static void
free_uid (gpointer key, gpointer value, gpointer data)
{
g_free (key);
}
/**
* camel_uid_cache_get_new_uids:
* @cache: a CamelUIDCache
* @uids: an array of UIDs
*
* Returns an array of UIDs from @uids that are not in @cache, and
* removes UIDs from @cache that aren't in @uids.
*
* Return value: an array of new UIDs, which must be freed with
* camel_uid_cache_free_uids().
**/
GPtrArray *
camel_uid_cache_get_new_uids (CamelUIDCache *cache, GPtrArray *uids)
{
GPtrArray *new_uids;
gpointer old_uid, old_level;
char *uid;
int i;
new_uids = g_ptr_array_new ();
cache->level++;
for (i = 0; i < uids->len; i++) {
uid = uids->pdata[i];
if (g_hash_table_lookup_extended (cache->uids, uid,
&old_uid, &old_level)) {
g_hash_table_remove (cache->uids, uid);
g_free (old_uid);
} else
g_ptr_array_add (new_uids, g_strdup (uid));
g_hash_table_insert (cache->uids, g_strdup (uid),
GINT_TO_POINTER (cache->level));
}
return new_uids;
}
/**
* camel_uid_cache_free_uids:
* @uids: an array returned from camel_uid_cache_get_new_uids()
*
* Frees the array of UIDs.
**/
void
camel_uid_cache_free_uids (GPtrArray *uids)
{
int i;
for (i = 0; i < uids->len; i++)
g_free (uids->pdata[i]);
g_ptr_array_free (uids, TRUE);
}
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