1 files changed, 59 insertions, 0 deletions
diff --git a/src/db/UniqueTags.cxx b/src/db/UniqueTags.cxx
new file mode 100644
index 000000000..589dc936d
--- /dev/null
+++ b/src/db/UniqueTags.cxx
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2003-2014 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "UniqueTags.hxx"
+#include "Interface.hxx"
+#include "LightSong.hxx"
+#include "tag/Set.hxx"
+
+#include <functional>
+
+#include <assert.h>
+
+static bool
+CollectTags(TagSet &set, TagType tag_type, uint32_t group_mask,
+	    const LightSong &song)
+{
+	assert(song.tag != nullptr);
+	const Tag &tag = *song.tag;
+
+	set.InsertUnique(tag, tag_type, group_mask);
+	return true;
+}
+
+bool
+VisitUniqueTags(const Database &db, const DatabaseSelection &selection,
+		TagType tag_type, uint32_t group_mask,
+		VisitTag visit_tag,
+		Error &error)
+{
+	TagSet set;
+
+	using namespace std::placeholders;
+	const auto f = std::bind(CollectTags, std::ref(set),
+				 tag_type, group_mask, _1);
+	if (!db.Visit(selection, f, error))
+		return false;
+
+	for (const auto &value : set)
+		if (!visit_tag(value, error))
+			return false;
+
+	return true;
+}