PlaylistEdit: postpone UpdateQueuedSong() when adding multiple songs

Implement a "bulk" edit mode that postpones both UpdateQueuedSong()
and OnModified().  This way, the playlist version gets incremented
only once.  More importantly: when adding multiple songs to a queue
that consists of only one song, the first song that got added will
always be played next.  By postponing this choice, all newly added
songs get a chance to become the next song.  Fixes the second (and
last) part of Mantis ticket 0004005.

1 files changed, 41 insertions, 0 deletions

diff --git a/src/BulkEdit.hxx b/src/BulkEdit.hxx
new file mode 100644
index 000000000..422dc4f38
--- /dev/null
+++ b/src/BulkEdit.hxx
@@ -0,0 +1,41 @@
+/*
+ * 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.
+ */
+
+#ifndef MPD_BULK_EDIT_HXX
+#define MPD_BULK_EDIT_HXX
+
+#include "Partition.hxx"
+
+/**
+ * Begin a "bulk edit" and commit it automatically.
+ */
+class ScopeBulkEdit {
+	Partition &partition;
+
+public:
+	ScopeBulkEdit(Partition &_partition):partition(_partition) {
+		partition.playlist.BeginBulk();
+	}
+
+	~ScopeBulkEdit() {
+		partition.playlist.CommitBulk(partition.pc);
+	}
+};
+
+#endif