1 files changed, 334 insertions, 0 deletions
diff --git a/camel/camel-uid-cache.c b/camel/camel-uid-cache.c
new file mode 100644
index 0000000000..f884c11851
--- /dev/null
+++ b/camel/camel-uid-cache.c
@@ -0,0 +1,334 @@
+/* -*- 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 version 2 of the GNU General Public 
+ * License as published by the Free Software Foundation.
+ *
+ * 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"
+#include "camel-file-utils.h"
+
+struct _uid_state {
+	int 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.
+ *
+ * Return value: a new UID cache, or %NULL
+ **/
+CamelUIDCache *
+camel_uid_cache_new (const char *filename)
+{
+	CamelUIDCache *cache;
+	struct stat st;
+	char *dirname, *buf, **uids;
+	int fd, i;
+	
+	dirname = g_path_get_dirname (filename);
+	if (camel_mkdir (dirname, 0777) == -1) {
+		g_free (dirname);
+		return NULL;
+	}
+	
+	g_free (dirname);
+	
+	if ((fd = open (filename, O_RDONLY | O_CREAT, 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) == -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)) == -1 || 
+		    camel_write (cache->fd, "\n", 1) == -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.
+ *
+ * Return value: success or failure
+ **/
+gboolean
+camel_uid_cache_save (CamelUIDCache *cache)
+{
+	char *filename;
+	int errnosav;
+	int fd;
+	
+	filename = g_strdup_printf ("%s~", cache->filename);
+	if ((fd = open (filename, O_WRONLY | O_CREAT | O_TRUNC, 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)
+		goto exception;
+	
+	if (fsync (fd) == -1)
+		goto exception;
+	
+	close (fd);
+	fd = -1;
+	
+	if (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 (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) {
+				cache->size = 0;
+				cache->expired = 0;
+				goto overwrite;
+			}
+		}
+		
+		close (fd);
+	}
+#endif
+	
+	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: 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;
+	char *uid;
+	int 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, (void **)&old_uid, (void **)&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 char *uid)
+{
+	struct _uid_state *state;
+	gpointer old_uid;
+	
+	g_return_if_fail (uid != NULL);
+
+	if (g_hash_table_lookup_extended (cache->uids, uid, (void **)&old_uid, (void **)&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: 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);
+}