aboutsummaryrefslogtreecommitdiffstats
path: root/camel/camel-uid-cache.c
blob: 83305c1fd30bb2c3d2cd872d166fd22b7b770f4c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-uid-cache.c: UID caching code. */

/* 
 * Authors:
 *  Dan Winship <danw@ximian.com>
 *
 * Copyright 2000 Ximian, Inc. (www.ximian.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);
}