From ef3ab5781a3730e019f92517366029540a960cd0 Mon Sep 17 00:00:00 2001
From: Carl Worth <cworth@cworth.org>
Date: Mon, 26 Oct 2009 14:12:56 -0700
Subject: [PATCH] tags: Replace sort() and reset() with prepare_iterator().

The previous functions were always called together, so we might as
well just have one function for this. Also, the reset() name was
poor, and prepare_iterator() is much more descriptive.
---
 message.cc        |  4 +---
 notmuch-private.h |  5 +----
 tags.c            | 24 ++++++++++++++++++------
 3 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/message.cc b/message.cc
index b95f9d7f..66dfc806 100644
--- a/message.cc
+++ b/message.cc
@@ -318,9 +318,7 @@ notmuch_message_get_tags (notmuch_message_t *message)
 	i++;
     }
 
-    _notmuch_tags_sort (tags);
-
-    _notmuch_tags_reset (tags);
+    _notmuch_tags_prepare_iterator (tags);
 
     return tags;
 }
diff --git a/notmuch-private.h b/notmuch-private.h
index 3d2610ad..c6d8e355 100644
--- a/notmuch-private.h
+++ b/notmuch-private.h
@@ -283,10 +283,7 @@ void
 _notmuch_tags_add_tag (notmuch_tags_t *tags, const char *tag);
 
 void
-_notmuch_tags_sort (notmuch_tags_t *tags);
-
-void
-_notmuch_tags_reset (notmuch_tags_t *tags);
+_notmuch_tags_prepare_iterator (notmuch_tags_t *tags);
 
 NOTMUCH_END_DECLS
 
diff --git a/tags.c b/tags.c
index 36f3fa40..afc132c5 100644
--- a/tags.c
+++ b/tags.c
@@ -23,6 +23,7 @@
 #include <glib.h> /* GList */
 
 struct _notmuch_tags {
+    int sorted;
     GList *tags;
     GList *iterator;
 };
@@ -52,27 +53,38 @@ _notmuch_tags_create (void *ctx)
 
     talloc_set_destructor (tags, _notmuch_tags_destructor);
 
+    tags->sorted = 1;
     tags->tags = NULL;
     tags->iterator = NULL;
 
     return tags;
 }
 
+/* Add a new tag to 'tags'. The tags object will create its own copy
+ * of the string.
+ *
+ * Note: The tags object will not do anything to prevent duplicate
+ * tags being stored, so the caller really shouldn't pass
+ * duplicates. */
 void
 _notmuch_tags_add_tag (notmuch_tags_t *tags, const char *tag)
 {
     tags->tags = g_list_prepend (tags->tags, talloc_strdup (tags, tag));
+    tags->sorted = 0;
 }
 
+/* Prepare 'tag' for iteration.
+ *
+ * The internal creator of 'tags' should call this function before
+ * returning 'tags' to the user to call the public functions such as
+ * notmuch_tags_has_more, notmuch_tags_get, and notmuch_tags_advance. */
 void
-_notmuch_tags_sort (notmuch_tags_t *tags)
+_notmuch_tags_prepare_iterator (notmuch_tags_t *tags)
 {
-    tags->tags = g_list_sort (tags->tags, (GCompareFunc) strcmp);
-}
+    if (! tags->sorted)
+	tags->tags = g_list_sort (tags->tags, (GCompareFunc) strcmp);
+    tags->sorted = 1;
 
-void
-_notmuch_tags_reset (notmuch_tags_t *tags)
-{
     tags->iterator = tags->tags;
 }