Add notmuch_thread_get_tags

And augment "notmuch search" to print tag values as well as thread ID
values. This tool is almost usable now.

notmuch-private.h

@@ -144,6 +144,9 @@ _notmuch_thread_create (const void *talloc_owner,
 			notmuch_database_t *notmuch,
 			const char *thread_id);
 
+void
+_notmuch_thread_add_tag (notmuch_thread_t *thread, const char *tag);
+
 /* message.cc */
 
 notmuch_message_t *

notmuch.c

@@ -610,6 +610,7 @@ search_command (int argc, char *argv[])
     notmuch_query_t *query;
     notmuch_thread_results_t *results;
     notmuch_thread_t *thread;
+    notmuch_tags_t *tags;
     char *query_str;
     int i;
     notmuch_status_t ret = NOTMUCH_STATUS_SUCCESS;
@@ -641,9 +642,23 @@ search_command (int argc, char *argv[])
 	 notmuch_thread_results_has_more (results);
 	 notmuch_thread_results_advance (results))
     {
+	int first = 1;
+
 	thread = notmuch_thread_results_get (results);
 
-	printf ("%s\n", notmuch_thread_get_thread_id (thread));
+	printf ("%s (", notmuch_thread_get_thread_id (thread));
+
+	for (tags = notmuch_thread_get_tags (thread);
+	     notmuch_tags_has_more (tags);
+	     notmuch_tags_advance (tags))
+	{
+	    if (! first)
+		printf (" ");
+	    printf ("%s", notmuch_tags_get (tags));
+	    first = 0;
+	}
+
+	printf (")\n");
 
 	notmuch_thread_destroy (thread);
     }

notmuch.h

@@ -458,6 +458,45 @@ notmuch_thread_results_destroy (notmuch_thread_results_t *results);
 const char *
 notmuch_thread_get_thread_id (notmuch_thread_t *thread);
 
+/* Get the tags for 'thread', returning a notmuch_tags_t object which
+ * can be used to iterate over all tags.
+ *
+ * Note: In the Notmuch database, tags are stored on individual
+ * messages, not on threads. So the tags returned here will be all
+ * tags of the messages which matched the search and which belong to
+ * this thread.
+ *
+ * The tags object is owned by the thread and as such, will only be
+ * valid for as long as the thread is valid, (for example, until
+ * notmuch_thread_destroy or until the query from which it derived is
+ * destroyed).
+ *
+ * Typical usage might be:
+ *
+ *     notmuch_thread_t *thread;
+ *     notmuch_tags_t *tags;
+ *     const char *tag;
+ *
+ *     thread = notmuch_thread_results_get (thread_results);
+ *
+ *     for (tags = notmuch_thread_get_tags (thread);
+ *          notmuch_tags_has_more (tags);
+ *          notmuch_result_advance (tags))
+ *     {
+ *         tag = notmuch_tags_get (tags);
+ *         ....
+ *     }
+ *
+ *     notmuch_thread_destroy (thread);
+ *
+ * Note that there's no explicit destructor needed for the
+ * notmuch_tags_t object. (For consistency, we do provide a
+ * notmuch_tags_destroy function, but there's no good reason to call
+ * it if the message is about to be destroyed).
+ */
+notmuch_tags_t *
+notmuch_thread_get_tags (notmuch_thread_t *thread);
+
 /* Destroy a notmuch_thread_t object. */
 void
 notmuch_thread_destroy (notmuch_thread_t *thread);

query.cc

@@ -39,7 +39,7 @@ struct _notmuch_message_results {
 
 struct _notmuch_thread_results {
     notmuch_database_t *notmuch;
-    GPtrArray *thread_ids;
+    GPtrArray *threads;
     unsigned int index;
 };
 
@@ -165,7 +165,7 @@ notmuch_query_search_messages (notmuch_query_t *query)
 static int
 _notmuch_thread_results_destructor (notmuch_thread_results_t *results)
 {
-    g_ptr_array_free (results->thread_ids, TRUE);
+    g_ptr_array_free (results->threads, TRUE);
 
     return 0;
 }
@@ -174,9 +174,12 @@ notmuch_thread_results_t *
 notmuch_query_search_threads (notmuch_query_t *query)
 {
     notmuch_thread_results_t *thread_results;
+    notmuch_thread_t *thread;
+    const char *thread_id;
     notmuch_message_results_t *message_results;
     notmuch_message_t *message;
-    const char *thread_id;
+    notmuch_tags_t *tags;
+    const char *tag;
     GHashTable *seen;
 
     thread_results = talloc (query, notmuch_thread_results_t);
@@ -184,7 +187,7 @@ notmuch_query_search_threads (notmuch_query_t *query)
 	return NULL;
 
     thread_results->notmuch = query->notmuch;
-    thread_results->thread_ids = g_ptr_array_new ();
+    thread_results->threads = g_ptr_array_new ();
     thread_results->index = 0;
 
     talloc_set_destructor (thread_results, _notmuch_thread_results_destructor);
@@ -197,18 +200,28 @@ notmuch_query_search_threads (notmuch_query_t *query)
 	 notmuch_message_results_advance (message_results))
     {
 	message = notmuch_message_results_get (message_results);
+
 	thread_id = notmuch_message_get_thread_id (message);
 
-	if (g_hash_table_lookup_extended (seen,
-					  thread_id, NULL, NULL))
+	if (! g_hash_table_lookup_extended (seen,
+					    thread_id, NULL,
+					    (void **) &thread))
 	{
-	    continue;
+	    thread = _notmuch_thread_create (query, query->notmuch,
+					     thread_id);
+
+	    g_hash_table_insert (seen, xstrdup (thread_id), thread);
+
+	    g_ptr_array_add (thread_results->threads, thread);
 	}
 
-	g_hash_table_insert (seen, xstrdup (thread_id), NULL);
-
-	g_ptr_array_add (thread_results->thread_ids,
-			 talloc_strdup (thread_results, thread_id));
+	for (tags = notmuch_message_get_tags (message);
+	     notmuch_tags_has_more (tags);
+	     notmuch_tags_advance (tags))
+	{
+	    tag = notmuch_tags_get (tags);
+	    _notmuch_thread_add_tag (thread, tag);
+	}
     }
 
     g_hash_table_unref (seen);
@@ -268,26 +281,17 @@ notmuch_message_results_destroy (notmuch_message_results_t *results)
 notmuch_bool_t
 notmuch_thread_results_has_more (notmuch_thread_results_t *results)
 {
-    return (results->index < results->thread_ids->len);
+    return (results->index < results->threads->len);
 }
 
 notmuch_thread_t *
 notmuch_thread_results_get (notmuch_thread_results_t *results)
 {
-    notmuch_thread_t *thread;
-    const char *thread_id;
-
     if (! notmuch_thread_results_has_more (results))
 	return NULL;
 
-    thread_id = (const char *) g_ptr_array_index (results->thread_ids,
-						  results->index);
-
-    thread = _notmuch_thread_create (results,
-				     results->notmuch,
-				     thread_id);
-
-    return thread;
+    return (notmuch_thread_t *) g_ptr_array_index (results->threads,
+						   results->index);
 }
 
 void

thread.cc

@@ -23,11 +23,22 @@
 
 #include <xapian.h>
 
+#include <glib.h> /* GHashTable */
+
 struct _notmuch_thread {
     notmuch_database_t *notmuch;
     char *thread_id;
+    GHashTable *tags;
 };
 
+static int
+_notmuch_thread_destructor (notmuch_thread_t *thread)
+{
+    g_hash_table_unref (thread->tags);
+
+    return 0;
+}
+
 /* Create a new notmuch_thread_t object for an existing document in
  * the database.
  *
@@ -54,8 +65,12 @@ _notmuch_thread_create (const void *talloc_owner,
     if (unlikely (thread == NULL))
 	return NULL;
 
+    talloc_set_destructor (thread, _notmuch_thread_destructor);
+
     thread->notmuch = notmuch;
     thread->thread_id = talloc_strdup (thread, thread_id);
+    thread->tags = g_hash_table_new_full (g_str_hash, g_str_equal,
+					  free, NULL);
 
     return thread;
 }
@@ -66,6 +81,34 @@ notmuch_thread_get_thread_id (notmuch_thread_t *thread)
     return thread->thread_id;
 }
 
+void
+_notmuch_thread_add_tag (notmuch_thread_t *thread, const char *tag)
+{
+    g_hash_table_insert (thread->tags, xstrdup (tag), NULL);
+}
+
+notmuch_tags_t *
+notmuch_thread_get_tags (notmuch_thread_t *thread)
+{
+    notmuch_tags_t *tags;
+    GList *keys, *l;
+
+    tags = _notmuch_tags_create (thread);
+    if (unlikely (tags == NULL))
+	return NULL;
+
+    keys = g_hash_table_get_keys (thread->tags);
+
+    for (l = keys; l; l = l->next)
+	_notmuch_tags_add_tag (tags, (char *) l->data);
+
+    g_list_free (keys);
+
+    _notmuch_tags_prepare_iterator (tags);
+
+    return tags;
+}
+
 void
 notmuch_thread_destroy (notmuch_thread_t *thread)
 {