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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-uid-cache.c: UID caching code
*
* Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
*
* 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.
*
* 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, see <http://www.gnu.org/licenses/>.
*
* Authors: Dan Winship <danw@ximian.com>
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <glib/gstdio.h>
#include "camel-file-utils.h"
#include "camel-uid-cache.h"
#include "camel-win32.h"
struct _uid_state {
gint level;
gboolean save;
};
/**
* 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.
*
* Returns: a new UID cache, or %NULL
**/
CamelUIDCache *
camel_uid_cache_new (const gchar *filename)
{
CamelUIDCache *cache;
struct stat st;
gchar *dirname, *buf, **uids;
gint fd, i;
dirname = g_path_get_dirname (filename);
if (g_mkdir_with_parents (dirname, 0700) == -1) {
g_free (dirname);
return NULL;
}
g_free (dirname);
if ((fd = g_open (filename, O_RDONLY | O_CREAT | O_BINARY, 0666)) == -1)
return NULL;
if (fstat (fd, &st) == -1) {
close (fd);
return NULL;
}
buf = g_malloc (st.st_size + 1);
if (st.st_size > 0 && camel_read (fd, buf, st.st_size, NULL, NULL) == -1) {
close (fd);
g_free (buf);
return NULL;
}
buf[st.st_size] = '\0';
close (fd);
cache = g_new (CamelUIDCache, 1);
cache->uids = g_hash_table_new (g_str_hash, g_str_equal);
cache->filename = g_strdup (filename);
cache->level = 1;
cache->expired = 0;
cache->size = 0;
cache->fd = -1;
uids = g_strsplit (buf, "\n", 0);
g_free (buf);
for (i = 0; uids[i]; i++) {
struct _uid_state *state;
state = g_new (struct _uid_state, 1);
state->level = cache->level;
state->save = TRUE;
g_hash_table_insert (cache->uids, uids[i], state);
}
g_free (uids);
return cache;
}
static void
maybe_write_uid (gpointer key,
gpointer value,
gpointer data)
{
CamelUIDCache *cache = data;
struct _uid_state *state = value;
if (cache->fd == -1)
return;
if (state && state->level == cache->level && state->save) {
if (camel_write (cache->fd, key, strlen (key), NULL, NULL) == -1 ||
camel_write (cache->fd, "\n", 1, NULL, NULL) == -1) {
cache->fd = -1;
} else {
cache->size += strlen (key) + 1;
}
} else {
/* keep track of how much space the expired uids would
* have taken up in the cache */
cache->expired += strlen (key) + 1;
}
}
/**
* camel_uid_cache_save:
* @cache: a CamelUIDCache
*
* Attempts to save @cache back to disk.
*
* Returns: success or failure
**/
gboolean
camel_uid_cache_save (CamelUIDCache *cache)
{
gchar *filename;
gint errnosav;
gint fd;
filename = g_strdup_printf ("%s~", cache->filename);
if ((fd = g_open (filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0666)) == -1) {
g_free (filename);
return FALSE;
}
cache->fd = fd;
cache->size = 0;
cache->expired = 0;
g_hash_table_foreach (cache->uids, maybe_write_uid, cache);
if (cache->fd == -1 || fsync (fd) == -1)
goto exception;
close (fd);
fd = -1;
cache->fd = -1;
if (g_rename (filename, cache->filename) == -1)
goto exception;
g_free (filename);
return TRUE;
exception:
errnosav = errno;
#ifdef ENABLE_SPASMOLYTIC
if (fd != -1) {
/*
* If our new cache size is larger than the old cache,
* even if we haven't finished writing it out
* successfully, we should still attempt to replace
* the old cache with the new cache because it will at
* least avoid re-downloading a few extra messages
* than if we just kept the old cache.
*
* Similarly, even if the new cache size is smaller
* than the old cache size, but we've expired enough
* uids to make up for the difference in size (or
* more), then we should replace the old cache with
* the new cache as well.
*/
if (g_stat (cache->filename, &st) == 0 &&
(cache->size > st.st_size || cache->size + cache->expired > st.st_size)) {
if (ftruncate (fd, (off_t) cache->size) != -1) {
close (fd);
g_rename (filename, cache->filename);
g_free (filename);
cache->expired = 0;
cache->size = 0;
cache->fd = -1;
return TRUE;
}
}
}
#endif
if (fd != -1) {
close (fd);
cache->fd = -1;
}
g_unlink (filename);
g_free (filename);
errno = errnosav;
return FALSE;
}
static void
free_uid (gpointer key,
gpointer value,
gpointer data)
{
g_free (key);
g_free (value);
}
/**
* 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);
g_free (cache->filename);
g_free (cache);
}
/**
* camel_uid_cache_get_new_uids:
* @cache: a CamelUIDCache
* @uids: (element-type utf8) (transfer none): 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.
*
* Returns: (element-type utf8) (transfer full): 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;
gchar *uid;
gint i;
new_uids = g_ptr_array_new ();
cache->level++;
for (i = 0; i < uids->len; i++) {
struct _uid_state *state;
uid = uids->pdata[i];
if (g_hash_table_lookup_extended (cache->uids, uid, (gpointer *) &old_uid, (gpointer *) &state)) {
g_hash_table_remove (cache->uids, uid);
g_free (old_uid);
} else {
g_ptr_array_add (new_uids, g_strdup (uid));
state = g_new (struct _uid_state, 1);
state->save = FALSE;
}
state->level = cache->level;
g_hash_table_insert (cache->uids, g_strdup (uid), state);
}
return new_uids;
}
/**
* camel_uid_cache_save_uid:
* @cache: a CamelUIDCache
* @uid: a uid to save
*
* Marks a uid for saving.
**/
void
camel_uid_cache_save_uid (CamelUIDCache *cache,
const gchar *uid)
{
struct _uid_state *state;
gpointer old_uid;
g_return_if_fail (uid != NULL);
if (g_hash_table_lookup_extended (cache->uids, uid, (gpointer *) &old_uid, (gpointer *) &state)) {
state->save = TRUE;
state->level = cache->level;
} else {
state = g_new (struct _uid_state, 1);
state->save = TRUE;
state->level = cache->level;
g_hash_table_insert (cache->uids, g_strdup (uid), state);
}
}
/**
* camel_uid_cache_free_uids:
* @uids: (element-type utf8) (transfer full): an array returned from camel_uid_cache_get_new_uids()
*
* Frees the array of UIDs.
**/
void
camel_uid_cache_free_uids (GPtrArray *uids)
{
gint i;
for (i = 0; i < uids->len; i++)
g_free (uids->pdata[i]);
g_ptr_array_free (uids, TRUE);
}
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