From 3993176b76487bf82ccd267a181926747a471993 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Thu, 7 Oct 2021 21:27:35 +0200
Subject: [PATCH] command/QueueCommands: support relative offsets in "addid"
A similar feature was present long ago in MPD, but was deprecated in
version 0.16 because the implementation was broken. This commit
re-adds the feature in a way that's well-defined and not broken.
Close https://github.com/MusicPlayerDaemon/MPD/issues/1221
---
NEWS | 1 +
doc/protocol.rst | 6 ++++++
src/command/QueueCommands.cxx | 33 ++++++++++++++++++++++++++++++++-
3 files changed, 39 insertions(+), 1 deletion(-)
diff --git a/NEWS b/NEWS
index 979f928e7..839e79835 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,7 @@ ver 0.23 (not yet released)
- new command "getvol"
- show the audio format in "playlistinfo"
- support "listfiles" with arbitrary storage plugins
+ - support relative positions in "addid"
* database
- proxy: require MPD 0.20 or later
- proxy: require libmpdclient 2.11 or later
diff --git a/doc/protocol.rst b/doc/protocol.rst
index dd50ad8b0..bd0f7dcd7 100644
--- a/doc/protocol.rst
+++ b/doc/protocol.rst
@@ -709,6 +709,12 @@ Whenever possible, ids should be used.
Id: 999
OK
+ If the second parameter is given, then the song is inserted at the
+ specified position. If the parameter starts with ``+`` or ``-``,
+ then it is relative to the current song; e.g. ``+1`` inserts right
+ after the current song and ``-1`` inserts right before the current
+ song. (``±0`` is not a legal value.)
+
.. _command_clear:
:command:`clear`
diff --git a/src/command/QueueCommands.cxx b/src/command/QueueCommands.cxx
index 5e24c0919..1bc30bbc7 100644
--- a/src/command/QueueCommands.cxx
+++ b/src/command/QueueCommands.cxx
@@ -115,9 +115,40 @@ handle_addid(Client &client, Request args, Response &r)
auto &partition = client.GetPartition();
int to = -1;
+
if (args.size > 1) {
const auto queue_length = partition.playlist.queue.GetLength();
- to = args.ParseUnsigned(1, queue_length);
+
+ const char *const s = args[1];
+ if (*s == '+' || *s == '-') {
+ /* relative to the current song */
+
+ const int current =
+ partition.playlist.GetCurrentPosition();
+ if (current < 0)
+ throw ProtocolError(ACK_ERROR_PLAYER_SYNC,
+ "No current song");
+
+ to = args.ParseInt(1, -current - 1,
+ queue_length - current);
+ if (to == 0)
+ throw ProtocolError(ACK_ERROR_ARG,
+ "Zero is not a legal relative position");
+
+ /* special case for negative offsets: the
+ offset "-1" shall insert the new song right
+ before the current song (just like "+1"
+ inserts right after the current song);
+ computationally, that would be a zero
+ offset, but that's not intuitive, so we
+ need to add one here */
+ if (to < 0)
+ ++to;
+
+ to += current;
+ } else
+ /* absolute position */
+ to = args.ParseUnsigned(1, queue_length);
}
const SongLoader loader(client);