tags: Re-implement tags iterator to avoid having C++ in the interface

We want to be able to iterate over tags stored in various ways, so
the previous TermIterator-based tags object just wasn't general
enough. The new interface is nice and simple, and involves only
C datatypes.

1 files changed, 104 insertions, 0 deletions

diff --git a/tags.c b/tags.c
new file mode 100644
index 0000000..36f3fa4
--- /dev/null
+++ b/tags.c
@@ -0,0 +1,104 @@
+/* tags.c - Iterator for tags returned from message or thread
+ *
+ * Copyright © 2009 Carl Worth
+ *
+ * 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 3 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, see http://www.gnu.org/licenses/ .
+ *
+ * Author: Carl Worth <cworth@cworth.org>
+ */
+
+#include "notmuch-private.h"
+
+#include <glib.h> /* GList */
+
+struct _notmuch_tags {
+    GList *tags;
+    GList *iterator;
+};
+
+/* XXX: Should write some talloc-friendly list to avoid the need for
+ * this. */
+static int
+_notmuch_tags_destructor (notmuch_tags_t *tags)
+{
+    g_list_free (tags->tags);
+
+    return 0;
+}
+
+/* Create a new notmuch_tags_t object, with 'ctx' as its talloc owner.
+ *
+ * This function can return NULL in case of out-of-memory.
+ */
+notmuch_tags_t *
+_notmuch_tags_create (void *ctx)
+{
+    notmuch_tags_t *tags;
+
+    tags = talloc (ctx, notmuch_tags_t);
+    if (unlikely (tags == NULL))
+	return NULL;
+
+    talloc_set_destructor (tags, _notmuch_tags_destructor);
+
+    tags->tags = NULL;
+    tags->iterator = NULL;
+
+    return tags;
+}
+
+void
+_notmuch_tags_add_tag (notmuch_tags_t *tags, const char *tag)
+{
+    tags->tags = g_list_prepend (tags->tags, talloc_strdup (tags, tag));
+}
+
+void
+_notmuch_tags_sort (notmuch_tags_t *tags)
+{
+    tags->tags = g_list_sort (tags->tags, (GCompareFunc) strcmp);
+}
+
+void
+_notmuch_tags_reset (notmuch_tags_t *tags)
+{
+    tags->iterator = tags->tags;
+}
+
+notmuch_bool_t
+notmuch_tags_has_more (notmuch_tags_t *tags)
+{
+    return tags->iterator != NULL;
+}
+
+const char *
+notmuch_tags_get (notmuch_tags_t *tags)
+{
+    if (tags->iterator)
+	return (char *) tags->iterator->data;
+    else
+	return NULL;
+}
+
+void
+notmuch_tags_advance (notmuch_tags_t *tags)
+{
+    tags->iterator = tags->iterator->next;
+}
+
+void
+notmuch_tags_destroy (notmuch_tags_t *tags)
+{
+    talloc_free (tags);
+}