Proposed fix managing shared playlists (see #7150)

Actually, when duplicating a track with "share playlist", the current
playlist is owned by the new created track(orig-track-id). The sharing
mecanism is made by diskstreams pointing on the same(shared) playlist.
Since playlist now owned by the new track, selecting another playlist in
the original track "forgets" the playlist for this track.You can't
select the shared playlist anymore from the original track.

This commit adds a way to keep trace of shared playlist between tracks.

1 files changed, 71 insertions, 0 deletions

diff --git a/libs/ardour/playlist.cc b/libs/ardour/playlist.cc
index cc6c0d3f40..d38c8d57bd 100644
--- a/libs/ardour/playlist.cc
+++ b/libs/ardour/playlist.cc
@@ -26,6 +26,7 @@
 
 #include "pbd/convert.h"
 #include "pbd/stateful_diff_command.h"
+#include "pbd/strsplit.h"
 #include "pbd/xml++.h"
 
 #include "ardour/debug.h"
@@ -157,6 +158,7 @@ Playlist::Playlist (boost::shared_ptr<const Playlist> other, string namestr, boo
 	, regions (*this)
 	, _type(other->_type)
 	, _orig_track_id (other->_orig_track_id)
+	, _shared_with_ids (other->_shared_with_ids)
 {
 	init (hide);
 
@@ -189,6 +191,7 @@ Playlist::Playlist (boost::shared_ptr<const Playlist> other, framepos_t start, f
 	, regions (*this)
 	, _type(other->_type)
 	, _orig_track_id (other->_orig_track_id)
+	, _shared_with_ids (other->_shared_with_ids)
 {
 	RegionReadLock rlock2 (const_cast<Playlist*> (other.get()));
 
@@ -2234,6 +2237,16 @@ Playlist::find_next_region (framepos_t frame, RegionPoint point, int dir)
 			 _frozen = string_is_affirmative (prop->value());
 		 } else if (prop->name() == X_("combine-ops")) {
 			 _combine_ops = atoi (prop->value());
+		 } else if (prop->name() == X_("shared-with-ids")) {
+			 string shared_ids = prop->value ();
+			 if (!shared_ids.empty()) {
+				vector<string> result;
+				::split (shared_ids, result, ',');
+				vector<string>::iterator it = result.begin();
+				for (; it != result.end(); ++it) {
+					_shared_with_ids.push_back (PBD::ID(*it));
+				}
+			 }
 		 }
 	 }
 
@@ -2321,6 +2334,17 @@ Playlist::state (bool full_state)
 
 	_orig_track_id.print (buf, sizeof (buf));
 	node->add_property (X_("orig-track-id"), buf);
+
+	string shared_ids;
+	list<PBD::ID>::const_iterator it = _shared_with_ids.begin();
+	for (; it != _shared_with_ids.end(); ++it) {
+		shared_ids += "," + (*it).to_s();
+	}
+	if (!shared_ids.empty()) {
+		shared_ids.erase(0,1);
+	}
+
+	node->add_property (X_("shared-with-ids"), shared_ids);
 	node->add_property (X_("frozen"), _frozen ? "yes" : "no");
 
 	if (full_state) {
@@ -3317,9 +3341,56 @@ Playlist::max_source_level () const
 void
 Playlist::set_orig_track_id (const PBD::ID& id)
 {
+	if (shared_with(id)) {
+		// Swap 'shared_id' / origin_track_id
+		unshare_with (id);
+		share_with (_orig_track_id);
+	}
 	_orig_track_id = id;
 }
 
+void
+Playlist::share_with (const PBD::ID& id)
+{
+	if (!shared_with(id)) {
+		_shared_with_ids.push_back (id);
+	}
+}
+
+void
+Playlist::unshare_with (const PBD::ID& id)
+{
+	list<PBD::ID>::iterator it = _shared_with_ids.begin ();
+	while (it != _shared_with_ids.end()) {
+		if (*it == id) {
+			_shared_with_ids.erase (it);
+			break;
+		}
+		++it;
+	}
+}
+
+bool
+Playlist::shared_with (const PBD::ID& id) const
+{
+	bool shared = false;
+	list<PBD::ID>::const_iterator it = _shared_with_ids.begin ();
+	while (it != _shared_with_ids.end() && !shared) {
+		if (*it == id) {
+			shared = true;
+		}
+		++it;
+	}
+
+	return shared;
+}
+
+void
+Playlist::reset_shares ()
+{
+	_shared_with_ids.clear();
+}
+
 /** Take a list of ranges, coalesce any that can be coalesced, then call
  *  check_crossfades for each one.
  */