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Diffstat (limited to 'camel/camel-uid-cache.c')
| -rw-r--r-- | camel/camel-uid-cache.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/camel/camel-uid-cache.c b/camel/camel-uid-cache.c new file mode 100644 index 0000000000..2b5faddb91 --- /dev/null +++ b/camel/camel-uid-cache.c @@ -0,0 +1,186 @@ +/* -*- 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 + */ + +#include "config.h" +#include "camel-uid-cache.h" + +#include <errno.h> +#include <fcntl.h> +#include <string.h> +#include <sys/stat.h> +#include <unistd.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; + 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 (cache->uids, uid)) + g_hash_table_remove (cache->uids, 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); +} |