use shared_ptr for all Playlist handling; cleanup works again

git-svn-id: svn://localhost/ardour2/trunk@1209 d708f5d6-7413-0410-9779-e7cbd77b26cf

28 files changed, 509 insertions, 367 deletions

diff --git a/libs/ardour/ardour/audio_diskstream.h b/libs/ardour/ardour/audio_diskstream.h
index 5c24697972..7c00885228 100644
--- a/libs/ardour/ardour/audio_diskstream.h
+++ b/libs/ardour/ardour/audio_diskstream.h
@@ -90,9 +90,9 @@ class AudioDiskstream : public Diskstream
 		}
 	}
 	
-	AudioPlaylist* audio_playlist () { return dynamic_cast<AudioPlaylist*>(_playlist); }
+	boost::shared_ptr<AudioPlaylist> audio_playlist () { return boost::dynamic_pointer_cast<AudioPlaylist>(_playlist); }
 
-	int use_playlist (Playlist *);
+	int use_playlist (boost::shared_ptr<Playlist>);
 	int use_new_playlist ();
 	int use_copy_playlist ();
 
diff --git a/libs/ardour/ardour/audioplaylist.h b/libs/ardour/ardour/audioplaylist.h
index 383ec73531..2f1b127c5a 100644
--- a/libs/ardour/ardour/audioplaylist.h
+++ b/libs/ardour/ardour/audioplaylist.h
@@ -42,8 +42,10 @@ class AudioPlaylist : public ARDOUR::Playlist
    public:
 	AudioPlaylist (Session&, const XMLNode&, bool hidden = false);
 	AudioPlaylist (Session&, string name, bool hidden = false);
-	AudioPlaylist (const AudioPlaylist&, string name, bool hidden = false);
-	AudioPlaylist (const AudioPlaylist&, nframes_t start, nframes_t cnt, string name, bool hidden = false);
+	AudioPlaylist (boost::shared_ptr<const AudioPlaylist>, string name, bool hidden = false);
+	AudioPlaylist (boost::shared_ptr<const AudioPlaylist>, nframes_t start, nframes_t cnt, string name, bool hidden = false);
+
+       ~AudioPlaylist (); /* public should use unref() */
 
 	void clear (bool with_signals=true);
 
@@ -70,9 +72,6 @@ class AudioPlaylist : public ARDOUR::Playlist
         void check_dependents (boost::shared_ptr<Region> region, bool norefresh);
         void remove_dependents (boost::shared_ptr<Region> region);
 
-    protected:
-       ~AudioPlaylist (); /* public should use unref() */
-
     private:
        Crossfades      _crossfades;    /* xfades currently in use */
        Crossfades      _pending_xfade_adds;
diff --git a/libs/ardour/ardour/audioregion.h b/libs/ardour/ardour/audioregion.h
index 0d45d20c0d..7a88655afe 100644
--- a/libs/ardour/ardour/audioregion.h
+++ b/libs/ardour/ardour/audioregion.h
@@ -137,7 +137,7 @@ class AudioRegion : public Region
 	void resume_fade_in ();
 	void resume_fade_out ();
 
-	void set_playlist (Playlist *);
+	void set_playlist (boost::weak_ptr<Playlist>);
 
   private:
 	friend class RegionFactory;
diff --git a/libs/ardour/ardour/crossfade.h b/libs/ardour/ardour/crossfade.h
index d29ba47056..0422698c5e 100644
--- a/libs/ardour/ardour/crossfade.h
+++ b/libs/ardour/ardour/crossfade.h
@@ -64,12 +64,13 @@ class Crossfade : public PBD::StatefulDestructible
 
 
 	/* copy constructor to copy a crossfade with new regions. used (for example)
-	   when a playlist copy is made */
+	   when a playlist copy is made 
+	*/
 	Crossfade (const Crossfade &, boost::shared_ptr<ARDOUR::AudioRegion>, boost::shared_ptr<ARDOUR::AudioRegion>);
 	
 	/* the usual XML constructor */
 
-	Crossfade (const ARDOUR::Playlist&, XMLNode&);
+	Crossfade (const Playlist&, XMLNode&);
 	virtual ~Crossfade();
 
 	bool operator== (const ARDOUR::Crossfade&);
diff --git a/libs/ardour/ardour/diskstream.h b/libs/ardour/ardour/diskstream.h
index 6e0725033a..3f30cd9f0e 100644
--- a/libs/ardour/ardour/diskstream.h
+++ b/libs/ardour/ardour/diskstream.h
@@ -104,9 +104,9 @@ class IO;
 	void set_speed (double);
 	void non_realtime_set_speed ();
 
-	Playlist* playlist () { return _playlist; }
+	boost::shared_ptr<Playlist> playlist () { return _playlist; }
 
-	virtual int use_playlist (Playlist *);
+	virtual int use_playlist (boost::shared_ptr<Playlist>);
 	virtual int use_new_playlist () = 0;
 	virtual int use_copy_playlist () = 0;
 
@@ -206,7 +206,7 @@ class IO;
 
 	virtual void playlist_changed (Change);
 	virtual void playlist_modified ();
-	virtual void playlist_deleted (Playlist*);
+	virtual void playlist_deleted (boost::weak_ptr<Playlist>);
 
 	virtual void finish_capture (bool rec_monitors_input) = 0;
 	virtual void transport_stopped (struct tm&, time_t, bool abort) = 0;
@@ -246,7 +246,8 @@ class IO;
 	ARDOUR::Session&  _session;
 	ARDOUR::IO*       _io;
 	uint32_t          _n_channels;
-	Playlist*         _playlist;
+
+	boost::shared_ptr<Playlist> _playlist;
 
 	mutable gint             _record_enabled;
 	double                   _visible_speed;
@@ -300,7 +301,6 @@ class IO;
 
 	sigc::connection ports_created_c;
 	sigc::connection plmod_connection;
-	sigc::connection plstate_connection;
 	sigc::connection plgone_connection;
 	
 	unsigned char _flags;
diff --git a/libs/ardour/ardour/named_selection.h b/libs/ardour/ardour/named_selection.h
index 87b71e73ff..fd5777ccf6 100644
--- a/libs/ardour/ardour/named_selection.h
+++ b/libs/ardour/ardour/named_selection.h
@@ -23,6 +23,7 @@
 
 #include <string>
 #include <list>
+#include <boost/shared_ptr.hpp>
 
 #include <pbd/stateful.h> 
 
@@ -35,12 +36,12 @@ class Playlist;
 
 struct NamedSelection : public Stateful
 {
-    NamedSelection (std::string, std::list<Playlist*>&);
+    NamedSelection (std::string, std::list<boost::shared_ptr<Playlist> >&);
     NamedSelection (Session&, const XMLNode&);
     virtual ~NamedSelection ();
 
     std::string name;
-    std::list<Playlist*> playlists;
+    std::list<boost::shared_ptr<Playlist> > playlists;
 
     XMLNode& get_state (void);
 
diff --git a/libs/ardour/ardour/playlist.h b/libs/ardour/ardour/playlist.h
index 7b9ae718bc..50282f3331 100644
--- a/libs/ardour/ardour/playlist.h
+++ b/libs/ardour/ardour/playlist.h
@@ -26,6 +26,7 @@
 #include <map>
 #include <list>
 #include <boost/shared_ptr.hpp>
+#include <boost/enable_shared_from_this.hpp>
 
 #include <sys/stat.h>
 
@@ -46,21 +47,25 @@ namespace ARDOUR  {
 class Session;
 class Region;
 
-class Playlist : public PBD::StatefulDestructible {
+class Playlist : public PBD::StatefulDestructible, public boost::enable_shared_from_this<Playlist> {
   public:
 	typedef list<boost::shared_ptr<Region> >    RegionList;
 
 	Playlist (Session&, const XMLNode&, bool hidden = false);
 	Playlist (Session&, string name, bool hidden = false);
-	Playlist (const Playlist&, string name, bool hidden = false);
-	Playlist (const Playlist&, nframes_t start, nframes_t cnt, string name, bool hidden = false);
+	Playlist (boost::shared_ptr<const Playlist>, string name, bool hidden = false);
+	Playlist (boost::shared_ptr<const Playlist>, nframes_t start, nframes_t cnt, string name, bool hidden = false);
+
+	virtual ~Playlist ();  
+
+	void set_region_ownership ();
 
 	virtual void clear (bool with_signals=true);
 	virtual void dump () const;
 
-	void ref();
-	void unref();
-	uint32_t refcnt() const { return _refcnt; }
+	void use();
+	void release();
+	bool used () const { return _refcnt != 0; }
 
 	std::string name() const { return _name; }
 	void set_name (std::string str);
@@ -89,9 +94,9 @@ class Playlist : public PBD::StatefulDestructible {
 	void duplicate (boost::shared_ptr<Region>, nframes_t position, float times);
 	void nudge_after (nframes_t start, nframes_t distance, bool forwards);
 
-	Playlist* cut  (list<AudioRange>&, bool result_is_hidden = true);
-	Playlist* copy (list<AudioRange>&, bool result_is_hidden = true);
-	int       paste (Playlist&, nframes_t position, float times);
+	boost::shared_ptr<Playlist> cut  (list<AudioRange>&, bool result_is_hidden = true);
+	boost::shared_ptr<Playlist> copy (list<AudioRange>&, bool result_is_hidden = true);
+	int                         paste (boost::shared_ptr<Playlist>, nframes_t position, float times);
 
 	RegionList*                regions_at (nframes_t frame);
 	RegionList*                regions_touched (nframes_t start, nframes_t end);
@@ -106,14 +111,11 @@ class Playlist : public PBD::StatefulDestructible {
 	int set_state (const XMLNode&);
 	XMLNode& get_template ();
 
-	sigc::signal<void,Playlist*,bool> InUse;
-	sigc::signal<void>                Modified;
-	sigc::signal<void>                NameChanged;
-	sigc::signal<void>                LengthChanged;
-	sigc::signal<void>                LayeringChanged;
-	sigc::signal<void>                StatePushed;
-
-	static sigc::signal<void,Playlist*> PlaylistCreated;
+	sigc::signal<void,bool> InUse;
+	sigc::signal<void>      Modified;
+	sigc::signal<void>      NameChanged;
+	sigc::signal<void>      LengthChanged;
+	sigc::signal<void>      LayeringChanged;
 
 	static string bump_name (string old_name, Session&);
 	static string bump_name_once (string old_name);
@@ -139,7 +141,6 @@ class Playlist : public PBD::StatefulDestructible {
 
   protected:
 	friend class Session;
-	virtual ~Playlist ();  /* members of the public use unref() */
 
   protected:
 	struct RegionLock {
@@ -240,26 +241,23 @@ class Playlist : public PBD::StatefulDestructible {
 
 	boost::shared_ptr<Region> region_by_id (PBD::ID);
 
-	void add_region_internal (boost::shared_ptr<Region>, nframes_t position, bool delay_sort = false);
-
-	int remove_region_internal (boost::shared_ptr<Region>, bool delay_sort = false);
+	void add_region_internal (boost::shared_ptr<Region>, nframes_t position);
+	
+	int remove_region_internal (boost::shared_ptr<Region>);
 	RegionList *find_regions_at (nframes_t frame);
 	void copy_regions (RegionList&) const;
 	void partition_internal (nframes_t start, nframes_t end, bool cutting, RegionList& thawlist);
 
 	nframes_t _get_maximum_extent() const;
 
-	Playlist* cut_copy (Playlist* (Playlist::*pmf)(nframes_t, nframes_t, bool), 
-			    list<AudioRange>& ranges, bool result_is_hidden);
-	Playlist *cut (nframes_t start, nframes_t cnt, bool result_is_hidden);
-	Playlist *copy (nframes_t start, nframes_t cnt, bool result_is_hidden);
+	boost::shared_ptr<Playlist> cut_copy (boost::shared_ptr<Playlist> (Playlist::*pmf)(nframes_t, nframes_t, bool), 
+					      list<AudioRange>& ranges, bool result_is_hidden);
+	boost::shared_ptr<Playlist> cut (nframes_t start, nframes_t cnt, bool result_is_hidden);
+	boost::shared_ptr<Playlist> copy (nframes_t start, nframes_t cnt, bool result_is_hidden);
 
 
 	int move_region_to_layer (layer_t, boost::shared_ptr<Region> r, int dir);
 	void relayer ();
-
-	static Playlist* copyPlaylist (const Playlist&, nframes_t start, nframes_t length,
-				       string name, bool result_is_hidden);
 	
 	void unset_freeze_parent (Playlist*);
 	void unset_freeze_child (Playlist*);
diff --git a/libs/ardour/ardour/region.h b/libs/ardour/ardour/region.h
index b27fef48a3..f0262777f3 100644
--- a/libs/ardour/ardour/region.h
+++ b/libs/ardour/ardour/region.h
@@ -162,9 +162,8 @@ class Region : public PBD::StatefulDestructible, public boost::enable_shared_fro
 
 	virtual uint32_t read_data_count() const { return _read_data_count; }
 
-	ARDOUR::Playlist* playlist() const { return _playlist; }
-
-	virtual void set_playlist (ARDOUR::Playlist*);
+	boost::shared_ptr<ARDOUR::Playlist> playlist() const { return _playlist.lock(); }
+	virtual void set_playlist (boost::weak_ptr<ARDOUR::Playlist>);
 
 	/* serialization */
 	
@@ -217,7 +216,7 @@ class Region : public PBD::StatefulDestructible, public boost::enable_shared_fro
 	mutable RegionEditState _first_edit;
 	int                     _frozen;
 	Glib::Mutex             lock;
-	ARDOUR::Playlist*       _playlist;
+	boost::weak_ptr<ARDOUR::Playlist> _playlist;
 	mutable uint32_t        _read_data_count; // modified in read()
 	Change                   pending_changed;
 	uint64_t                _last_layer_op; // timestamp
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index 55376bcd77..6ce7f75832 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -604,8 +604,7 @@ class Session : public PBD::StatefulDestructible
 	   this playlist.
 	*/
 	
-	sigc::signal<int,ARDOUR::Playlist*> AskAboutPlaylistDeletion;
-
+	sigc::signal<int,boost::shared_ptr<ARDOUR::Playlist> > AskAboutPlaylistDeletion;
 
 	/* handlers should return !0 for use pending state, 0 for
 	   ignore it.
@@ -613,24 +612,21 @@ class Session : public PBD::StatefulDestructible
 
 	static sigc::signal<int> AskAboutPendingState;
 	
-	sigc::signal<void,boost::shared_ptr<Source> > SourceAdded;
-	sigc::signal<void,boost::shared_ptr<Source> > SourceRemoved;
-
 	boost::shared_ptr<AudioFileSource> create_audio_source_for_session (ARDOUR::AudioDiskstream&, uint32_t which_channel, bool destructive);
 
 	boost::shared_ptr<Source> source_by_id (const PBD::ID&);
 
 	/* playlist management */
 
-	Playlist* playlist_by_name (string name);
-	void add_playlist (Playlist *);
-	sigc::signal<void,Playlist*> PlaylistAdded;
-	sigc::signal<void,Playlist*> PlaylistRemoved;
+	boost::shared_ptr<Playlist> playlist_by_name (string name);
+	void add_playlist (boost::shared_ptr<Playlist>);
+	sigc::signal<void,boost::shared_ptr<Playlist> > PlaylistAdded;
+	sigc::signal<void,boost::shared_ptr<Playlist> > PlaylistRemoved;
 
 	uint32_t n_playlists() const;
 
-	template<class T> void foreach_playlist (T *obj, void (T::*func)(Playlist *));
-	void get_playlists (std::vector<Playlist*>&);
+	template<class T> void foreach_playlist (T *obj, void (T::*func)(boost::shared_ptr<Playlist>));
+	void get_playlists (std::vector<boost::shared_ptr<Playlist> >&);
 
 	/* named selections */
 
@@ -1464,19 +1460,19 @@ class Session : public PBD::StatefulDestructible
 	/* PLAYLISTS */
 	
 	mutable Glib::Mutex playlist_lock;
-	typedef set<Playlist *> PlaylistList;
+	typedef set<boost::shared_ptr<Playlist> > PlaylistList;
 	PlaylistList playlists;
 	PlaylistList unused_playlists;
 
 	int load_playlists (const XMLNode&);
 	int load_unused_playlists (const XMLNode&);
-	void remove_playlist (Playlist *);
-	void track_playlist (Playlist *, bool);
+	void remove_playlist (boost::weak_ptr<Playlist>);
+	void track_playlist (bool, boost::weak_ptr<Playlist>);
 
-	Playlist *playlist_factory (string name);
-	Playlist *XMLPlaylistFactory (const XMLNode&);
+	boost::shared_ptr<Playlist> playlist_factory (string name);
+	boost::shared_ptr<Playlist> XMLPlaylistFactory (const XMLNode&);
 
-	void playlist_length_changed (Playlist *);
+	void playlist_length_changed ();
 	void diskstream_playlist_changed (boost::shared_ptr<Diskstream>);
 
 	/* NAMED SELECTIONS */
diff --git a/libs/ardour/ardour/session_playlist.h b/libs/ardour/ardour/session_playlist.h
index 6f1b8dbd12..20cf4d8f2e 100644
--- a/libs/ardour/ardour/session_playlist.h
+++ b/libs/ardour/ardour/session_playlist.h
@@ -27,7 +27,7 @@
 namespace ARDOUR {
 
 template<class T> void 
-Session::foreach_playlist (T *obj, void (T::*func)(Playlist *)) 
+Session::foreach_playlist (T *obj, void (T::*func)(boost::shared_ptr<Playlist>)) 
 {
 	Glib::Mutex::Lock lm (playlist_lock);
 	for (PlaylistList::iterator i = playlists.begin(); i != playlists.end(); i++) {
diff --git a/libs/ardour/ardour/source.h b/libs/ardour/ardour/source.h
index 15e814e946..91b856894d 100644
--- a/libs/ardour/ardour/source.h
+++ b/libs/ardour/ardour/source.h
@@ -54,8 +54,8 @@ class Source : public PBD::StatefulDestructible
 	void use () { _in_use++; }
 	void disuse () { if (_in_use) { _in_use--; } }
 
-	void add_playlist (ARDOUR::Playlist*);
-	void remove_playlist (ARDOUR::Playlist*);
+	void add_playlist (boost::shared_ptr<ARDOUR::Playlist>);
+	void remove_playlist (boost::weak_ptr<ARDOUR::Playlist>);
 
 	uint32_t used() const;
 
@@ -64,7 +64,7 @@ class Source : public PBD::StatefulDestructible
 	string            _name;
 	time_t            _timestamp;
 
-	std::set<ARDOUR::Playlist*> _playlists;
+	std::set<boost::shared_ptr<ARDOUR::Playlist> > _playlists;
 
   private:
 	uint32_t          _in_use;
diff --git a/libs/ardour/ardour/track.h b/libs/ardour/ardour/track.h
index a2b0b9b90e..9c99ecfd25 100644
--- a/libs/ardour/ardour/track.h
+++ b/libs/ardour/ardour/track.h
@@ -120,13 +120,12 @@ class Track : public Route
 
 	struct FreezeRecord {
 	    FreezeRecord()
-		: playlist(0)
-		, have_mementos(false)
+		: have_mementos(false)
 	    {}
 
 	    ~FreezeRecord();
 
-	    Playlist*                       playlist;
+	    boost::shared_ptr<Playlist>     playlist;
 	    vector<FreezeRecordInsertInfo*> insert_info;
 	    bool                            have_mementos;
 	    FreezeState                     state;
diff --git a/libs/ardour/audio_diskstream.cc b/libs/ardour/audio_diskstream.cc
index 5f682789ef..e30c683d8e 100644
--- a/libs/ardour/audio_diskstream.cc
+++ b/libs/ardour/audio_diskstream.cc
@@ -46,6 +46,7 @@
 #include <ardour/send.h>
 #include <ardour/region_factory.h>
 #include <ardour/audioplaylist.h>
+#include <ardour/playlist_factory.h>
 #include <ardour/cycle_timer.h>
 #include <ardour/audioregion.h>
 #include <ardour/source_factory.h>
@@ -286,15 +287,13 @@ AudioDiskstream::get_input_sources ()
 int
 AudioDiskstream::find_and_use_playlist (const string& name)
 {
-	Playlist* pl;
-	AudioPlaylist* playlist;
+	boost::shared_ptr<AudioPlaylist> playlist;
 		
-	if ((pl = _session.playlist_by_name (name)) == 0) {
-		playlist = new AudioPlaylist(_session, name);
-		pl = playlist;
+	if ((playlist = boost::dynamic_pointer_cast<AudioPlaylist> (_session.playlist_by_name (name))) == 0) {
+		playlist = boost::dynamic_pointer_cast<AudioPlaylist> (PlaylistFactory::create (_session, name));
 	}
 
-	if ((playlist = dynamic_cast<AudioPlaylist*> (pl)) == 0) {
+	if (!playlist) {
 		error << string_compose(_("AudioDiskstream: Playlist \"%1\" isn't an audio playlist"), name) << endmsg;
 		return -1;
 	}
@@ -303,9 +302,9 @@ AudioDiskstream::find_and_use_playlist (const string& name)
 }
 
 int
-AudioDiskstream::use_playlist (Playlist* playlist)
+AudioDiskstream::use_playlist (boost::shared_ptr<Playlist> playlist)
 {
-	assert(dynamic_cast<AudioPlaylist*>(playlist));
+	assert(boost::dynamic_pointer_cast<AudioPlaylist>(playlist));
 
 	Diskstream::use_playlist(playlist);
 
@@ -316,7 +315,7 @@ int
 AudioDiskstream::use_new_playlist ()
 {
 	string newname;
-	AudioPlaylist* playlist;
+	boost::shared_ptr<AudioPlaylist> playlist;
 
 	if (!in_set_state && destructive()) {
 		return 0;
@@ -328,9 +327,11 @@ AudioDiskstream::use_new_playlist ()
 		newname = Playlist::bump_name (_name, _session);
 	}
 
-	if ((playlist = new AudioPlaylist (_session, newname, hidden())) != 0) {
+	if ((playlist = boost::dynamic_pointer_cast<AudioPlaylist> (PlaylistFactory::create (_session, newname, hidden()))) != 0) {
+		
 		playlist->set_orig_diskstream_id (id());
 		return use_playlist (playlist);
+
 	} else { 
 		return -1;
 	}
@@ -351,11 +352,11 @@ AudioDiskstream::use_copy_playlist ()
 	}
 
 	string newname;
-	AudioPlaylist* playlist;
+	boost::shared_ptr<AudioPlaylist> playlist;
 
 	newname = Playlist::bump_name (_playlist->name(), _session);
 	
-	if ((playlist  = new AudioPlaylist (*audio_playlist(), newname)) != 0) {
+	if ((playlist  = boost::dynamic_pointer_cast<AudioPlaylist>(PlaylistFactory::create (audio_playlist(), newname))) != 0) {
 		playlist->set_orig_diskstream_id (id());
 		return use_playlist (playlist);
 	} else { 
diff --git a/libs/ardour/audio_playlist.cc b/libs/ardour/audio_playlist.cc
index dd0f313fc4..0c35599332 100644
--- a/libs/ardour/audio_playlist.cc
+++ b/libs/ardour/audio_playlist.cc
@@ -45,39 +45,31 @@ AudioPlaylist::AudioPlaylist (Session& session, const XMLNode& node, bool hidden
 	in_set_state++;
 	set_state (node);
 	in_set_state--;
-
-	if (!hidden) {
-		PlaylistCreated (this); /* EMIT SIGNAL */
-	}
 }
 
 AudioPlaylist::AudioPlaylist (Session& session, string name, bool hidden)
 	: Playlist (session, name, hidden)
 {
-	if (!hidden) {
-		PlaylistCreated (this); /* EMIT SIGNAL */
-	}
-
 }
 
-AudioPlaylist::AudioPlaylist (const AudioPlaylist& other, string name, bool hidden)
+AudioPlaylist::AudioPlaylist (boost::shared_ptr<const AudioPlaylist> other, string name, bool hidden)
 	: Playlist (other, name, hidden)
 {
-	RegionList::const_iterator in_o  = other.regions.begin();
+	RegionList::const_iterator in_o  = other->regions.begin();
 	RegionList::iterator in_n = regions.begin();
 
-	while (in_o != other.regions.end()) {
+	while (in_o != other->regions.end()) {
 		boost::shared_ptr<AudioRegion> ar = boost::dynamic_pointer_cast<AudioRegion>(*in_o);
 
 		// We look only for crossfades which begin with the current region, so we don't get doubles
-		for (list<Crossfade *>::const_iterator xfades = other._crossfades.begin(); xfades != other._crossfades.end(); ++xfades) {
+		for (list<Crossfade *>::const_iterator xfades = other->_crossfades.begin(); xfades != other->_crossfades.end(); ++xfades) {
 			if ((*xfades)->in() == ar) {
 				// We found one! Now copy it!
 
-				RegionList::const_iterator out_o = other.regions.begin();
+				RegionList::const_iterator out_o = other->regions.begin();
 				RegionList::const_iterator out_n = regions.begin();
 
-				while (out_o != other.regions.end()) {
+				while (out_o != other->regions.end()) {
 					
 					boost::shared_ptr<AudioRegion>ar2 = boost::dynamic_pointer_cast<AudioRegion>(*out_o);
 					
@@ -99,13 +91,9 @@ AudioPlaylist::AudioPlaylist (const AudioPlaylist& other, string name, bool hidd
 		in_o++;
 		in_n++;
 	}
-
-	if (!hidden) {
-		PlaylistCreated (this); /* EMIT SIGNAL */
-	}
 }
 
-AudioPlaylist::AudioPlaylist (const AudioPlaylist& other, nframes_t start, nframes_t cnt, string name, bool hidden)
+AudioPlaylist::AudioPlaylist (boost::shared_ptr<const AudioPlaylist> other, nframes_t start, nframes_t cnt, string name, bool hidden)
 	: Playlist (other, start, cnt, name, hidden)
 {
 	/* this constructor does NOT notify others (session) */
@@ -658,7 +646,7 @@ AudioPlaylist::destroy_region (boost::shared_ptr<Region> region)
 			x = xtmp;
 		}
 
-		region->set_playlist (0);
+		region->set_playlist (boost::shared_ptr<Playlist>());
 	}
 
 	for (c = _crossfades.begin(); c != _crossfades.end(); ) {
diff --git a/libs/ardour/audio_track.cc b/libs/ardour/audio_track.cc
index b5a18073f4..33bb478a1c 100644
--- a/libs/ardour/audio_track.cc
+++ b/libs/ardour/audio_track.cc
@@ -32,6 +32,7 @@
 #include <ardour/route_group_specialized.h>
 #include <ardour/insert.h>
 #include <ardour/audioplaylist.h>
+#include <ardour/playlist_factory.h>
 #include <ardour/panner.h>
 #include <ardour/utils.h>
 
@@ -395,11 +396,11 @@ AudioTrack::set_state_part_two ()
 		_freeze_record.insert_info.clear ();
 		
 		if ((prop = fnode->property (X_("playlist"))) != 0) {
-			Playlist* pl = _session.playlist_by_name (prop->value());
+			boost::shared_ptr<Playlist> pl = _session.playlist_by_name (prop->value());
 			if (pl) {
-				_freeze_record.playlist = dynamic_cast<AudioPlaylist*> (pl);
+				_freeze_record.playlist = boost::dynamic_pointer_cast<AudioPlaylist> (pl);
 			} else {
-				_freeze_record.playlist = 0;
+				_freeze_record.playlist.reset ();
 				_freeze_record.state = NoFreeze;
 			return;
 			}
@@ -685,8 +686,7 @@ AudioTrack::export_stuff (vector<Sample*>& buffers, uint32_t nbufs, nframes_t st
 	
 	Glib::RWLock::ReaderLock rlock (redirect_lock);
 
-	// FIXME
-	AudioPlaylist* const apl = dynamic_cast<AudioPlaylist*>(diskstream->playlist());
+	boost::shared_ptr<AudioPlaylist> apl = boost::dynamic_pointer_cast<AudioPlaylist>(diskstream->playlist());
 	assert(apl);
 
 	if (apl->read (buffers[0], mix_buffer, gain_buffer, start, nframes) != nframes) {
@@ -791,12 +791,12 @@ AudioTrack::freeze (InterThreadInfo& itt)
 {
 	vector<boost::shared_ptr<AudioSource> > srcs;
 	string new_playlist_name;
-	Playlist* new_playlist;
+	boost::shared_ptr<Playlist> new_playlist;
 	string dir;
 	string region_name;
 	boost::shared_ptr<AudioDiskstream> diskstream = audio_diskstream();
 	
-	if ((_freeze_record.playlist = dynamic_cast<AudioPlaylist*>(diskstream->playlist())) == 0) {
+	if ((_freeze_record.playlist = boost::dynamic_pointer_cast<AudioPlaylist>(diskstream->playlist())) == 0) {
 		return;
 	}
 
@@ -853,7 +853,7 @@ AudioTrack::freeze (InterThreadInfo& itt)
 		}
 	}
 
-	new_playlist = new AudioPlaylist (_session, new_playlist_name, false);
+	new_playlist = PlaylistFactory::create (_session, new_playlist_name, false);
 	region_name = new_playlist_name;
 
 	/* create a new region from all filesources, keep it private */
@@ -868,7 +868,7 @@ AudioTrack::freeze (InterThreadInfo& itt)
 	new_playlist->set_frozen (true);
 	region->set_locked (true);
 
-	diskstream->use_playlist (dynamic_cast<AudioPlaylist*>(new_playlist));
+	diskstream->use_playlist (boost::dynamic_pointer_cast<AudioPlaylist>(new_playlist));
 	diskstream->set_record_enabled (false);
 
 	_freeze_record.state = Frozen;
@@ -900,7 +900,7 @@ AudioTrack::unfreeze ()
 			}
 		}
 		
-		_freeze_record.playlist = 0;
+		_freeze_record.playlist.reset ();
 	}
 
 	_freeze_record.state = UnFrozen;
diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index 1be0f66125..32bd6cd685 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -306,9 +306,11 @@ AudioRegion::AudioRegion (SourceList& srcs, const XMLNode& node)
 
 AudioRegion::~AudioRegion ()
 {
-	if (_playlist) {
+	boost::shared_ptr<Playlist> pl (playlist());
+
+	if (pl) {
 		for (SourceList::const_iterator i = sources.begin(); i != sources.end(); ++i) {
-			(*i)->remove_playlist (_playlist);
+			(*i)->remove_playlist (pl);
 		}
 	}
 
@@ -1159,11 +1161,13 @@ AudioRegion::exportme (Session& session, AudioExportSpecification& spec)
 boost::shared_ptr<Region>
 AudioRegion::get_parent() const
 {
-	if (_playlist) {
+	boost::shared_ptr<Playlist> pl (playlist());
+
+	if (pl) {
 		boost::shared_ptr<AudioRegion> ar;
 		boost::shared_ptr<AudioRegion const> grrr2 = boost::dynamic_pointer_cast<AudioRegion const> (shared_from_this());
 		
-		if (grrr2 && (ar = _playlist->session().find_whole_file_parent (grrr2))) {
+		if (grrr2 && (ar = pl->session().find_whole_file_parent (grrr2))) {
 			return boost::static_pointer_cast<Region> (ar);
 		}
 	}
@@ -1174,12 +1178,14 @@ AudioRegion::get_parent() const
 void
 AudioRegion::set_scale_amplitude (gain_t g)
 {
+	boost::shared_ptr<Playlist> pl (playlist());
+
 	_scale_amplitude = g;
 
 	/* tell the diskstream we're in */
-
-	if (_playlist) {
-		_playlist->Modified();
+	
+	if (pl) {
+		pl->Modified();
 	}
 
 	/* tell everybody else */
@@ -1246,8 +1252,10 @@ AudioRegion::normalize_to (float target_dB)
 
 	/* tell the diskstream we're in */
 
-	if (_playlist) {
-		_playlist->Modified();
+	boost::shared_ptr<Playlist> pl (playlist());
+
+	if (pl) {
+		pl->Modified();
 	}
 
 	/* tell everybody else */
@@ -1330,31 +1338,32 @@ AudioRegion::source_offset_changed ()
 }
 
 void
-AudioRegion::set_playlist (Playlist* pl)
+AudioRegion::set_playlist (boost::weak_ptr<Playlist> wpl)
 {
-	if (pl == _playlist) {
+	boost::shared_ptr<Playlist> old_playlist = (_playlist.lock());
+	boost::shared_ptr<Playlist> pl (wpl.lock());
+
+	if (old_playlist == pl) {
 		return;
 	}
 
-	Playlist* old_playlist = _playlist;
-
-	Region::set_playlist (pl);
+	Region::set_playlist (wpl);
 
 	if (pl) {
 		if (old_playlist) {
 			for (SourceList::const_iterator i = sources.begin(); i != sources.end(); ++i) {
-				(*i)->remove_playlist (old_playlist);	
-				(*i)->add_playlist (_playlist);
+				(*i)->remove_playlist (_playlist);	
+				(*i)->add_playlist (pl);
 			}
 		} else {
 			for (SourceList::const_iterator i = sources.begin(); i != sources.end(); ++i) {
-				(*i)->add_playlist (_playlist);
+				(*i)->add_playlist (pl);
 			}
 		}
 	} else {
 		if (old_playlist) {
 			for (SourceList::const_iterator i = sources.begin(); i != sources.end(); ++i) {
-				(*i)->remove_playlist (old_playlist);
+				(*i)->remove_playlist (_playlist);
 			}
 		}
 	}
diff --git a/libs/ardour/auditioner.cc b/libs/ardour/auditioner.cc
index 0c5e8bc6a2..ce6bcd4143 100644
--- a/libs/ardour/auditioner.cc
+++ b/libs/ardour/auditioner.cc
@@ -75,7 +75,7 @@ AudioPlaylist&
 Auditioner::prepare_playlist ()
 {
 	// FIXME auditioner is still audio-only
-	AudioPlaylist* const apl = dynamic_cast<AudioPlaylist*>(_diskstream->playlist());
+	boost::shared_ptr<AudioPlaylist> apl = boost::dynamic_pointer_cast<AudioPlaylist>(_diskstream->playlist());
 	assert(apl);
 
 	apl->clear ();
diff --git a/libs/ardour/diskstream.cc b/libs/ardour/diskstream.cc
index 7b3db9aab4..62c3fffeb6 100644
--- a/libs/ardour/diskstream.cc
+++ b/libs/ardour/diskstream.cc
@@ -71,14 +71,12 @@ sigc::signal<void>                Diskstream::DiskUnderrun;
 Diskstream::Diskstream (Session &sess, const string &name, Flag flag)
 	: _name (name)
 	, _session (sess)
-	, _playlist(NULL)
 {
 	init (flag);
 }
 	
 Diskstream::Diskstream (Session& sess, const XMLNode& node)
 	: _session (sess)
-	, _playlist(NULL)
 {
 	init (Recordable);
 }
@@ -133,7 +131,7 @@ Diskstream::~Diskstream ()
 	//Glib::Mutex::Lock lm (state_lock);
 
 	if (_playlist)
-		_playlist->unref ();
+		_playlist->release ();
 }
 
 void
@@ -307,7 +305,7 @@ Diskstream::set_speed (double sp)
 }
 
 int
-Diskstream::use_playlist (Playlist* playlist)
+Diskstream::use_playlist (boost::shared_ptr<Playlist> playlist)
 {
 	{
 		Glib::Mutex::Lock lm (state_lock);
@@ -316,23 +314,22 @@ Diskstream::use_playlist (Playlist* playlist)
 			return 0;
 		}
 
-		plstate_connection.disconnect();
 		plmod_connection.disconnect ();
 		plgone_connection.disconnect ();
 
 		if (_playlist) {
-			_playlist->unref();
+			_playlist->release();
 		}
 			
 		_playlist = playlist;
-		_playlist->ref();
+		_playlist->use();
 
 		if (!in_set_state && recordable()) {
 			reset_write_sources (false);
 		}
 		
 		plmod_connection = _playlist->Modified.connect (mem_fun (*this, &Diskstream::playlist_modified));
-		plgone_connection = _playlist->GoingAway.connect (bind (mem_fun (*this, &Diskstream::playlist_deleted), _playlist));
+		plgone_connection = _playlist->GoingAway.connect (bind (mem_fun (*this, &Diskstream::playlist_deleted), boost::weak_ptr<Playlist>(_playlist)));
 	}
 
 	if (!overwrite_queued) {
@@ -362,14 +359,21 @@ Diskstream::playlist_modified ()
 }
 
 void
-Diskstream::playlist_deleted (Playlist* pl)
+Diskstream::playlist_deleted (boost::weak_ptr<Playlist> wpl)
 {
-	/* this catches an ordering issue with session destruction. playlists 
-	   are destroyed before diskstreams. we have to invalidate any handles
-	   we have to the playlist.
-	*/
+	boost::shared_ptr<Playlist> pl (wpl.lock());
 
-	_playlist = 0;
+	if (pl == _playlist) {
+
+		/* this catches an ordering issue with session destruction. playlists 
+		   are destroyed before diskstreams. we have to invalidate any handles
+		   we have to the playlist.
+		*/
+		
+		if (_playlist) {
+			_playlist.reset ();
+		} 
+	}
 }
 
 int
diff --git a/libs/ardour/import.cc b/libs/ardour/import.cc
index 2d409e11f7..0d0a73c7a0 100644
--- a/libs/ardour/import.cc
+++ b/libs/ardour/import.cc
@@ -111,14 +111,14 @@ Session::import_audiofile (import_status& status)
 		do {
 			if (info.channels == 2) {
 				if (n == 0) {
-					snprintf (buf, sizeof(buf), "%s%s-L.wav", sounds_dir.c_str(), basepath.c_str());
+					snprintf (buf, sizeof(buf), "%s/%s-L.wav", sounds_dir.c_str(), basepath.c_str());
 				} else {
-					snprintf (buf, sizeof(buf), "%s%s-R.wav", sounds_dir.c_str(), basepath.c_str());
+					snprintf (buf, sizeof(buf), "%s/%s-R.wav", sounds_dir.c_str(), basepath.c_str());
 				}
 			} else if (info.channels > 1) {
-				snprintf (buf, sizeof(buf), "%s%s-c%lu.wav", sounds_dir.c_str(), basepath.c_str(), n+1);
+				snprintf (buf, sizeof(buf), "%s/%s-c%lu.wav", sounds_dir.c_str(), basepath.c_str(), n+1);
 			} else {
-				snprintf (buf, sizeof(buf), "%s%s.wav", sounds_dir.c_str(), basepath.c_str());
+				snprintf (buf, sizeof(buf), "%s/%s.wav", sounds_dir.c_str(), basepath.c_str());
 			}
 
 			if (::access (buf, F_OK) == 0) {
diff --git a/libs/ardour/named_selection.cc b/libs/ardour/named_selection.cc
index 605d7cae13..ecce09692f 100644
--- a/libs/ardour/named_selection.cc
+++ b/libs/ardour/named_selection.cc
@@ -33,12 +33,14 @@ using namespace PBD;
 
 sigc::signal<void,NamedSelection*> NamedSelection::NamedSelectionCreated;
 
-NamedSelection::NamedSelection (string n, list<Playlist*>& l) 
+typedef std::list<boost::shared_ptr<Playlist> > PlaylistList;
+
+NamedSelection::NamedSelection (string n, PlaylistList& l) 
 	: name (n)
 {
 	playlists = l;
-	for (list<Playlist*>::iterator i = playlists.begin(); i != playlists.end(); ++i) {
-		(*i)->ref();
+	for (PlaylistList::iterator i = playlists.begin(); i != playlists.end(); ++i) {
+		(*i)->use();
 	}
 	NamedSelectionCreated (this);
 }
@@ -65,13 +67,13 @@ NamedSelection::NamedSelection (Session& session, const XMLNode& node)
 
 		const XMLNode* plnode;
 		string playlist_name;
-		Playlist* playlist;
+		boost::shared_ptr<Playlist> playlist;
 
 		plnode = *niter;
 
 		if ((property = plnode->property ("name")) != 0) {
 			if ((playlist = session.playlist_by_name (property->value())) != 0) {
-				playlist->ref();
+				playlist->use();
 				playlists.push_back (playlist);
 			} else {
 				warning << string_compose (_("Chunk %1 uses an unknown playlist \"%2\""), name, property->value()) << endmsg;
@@ -87,8 +89,8 @@ NamedSelection::NamedSelection (Session& session, const XMLNode& node)
 
 NamedSelection::~NamedSelection ()
 {
-	for (list<Playlist*>::iterator i = playlists.begin(); i != playlists.end(); ++i) {
-		(*i)->unref();
+	for (PlaylistList::iterator i = playlists.begin(); i != playlists.end(); ++i) {
+		(*i)->release();
 	}
 }
 
@@ -107,7 +109,7 @@ NamedSelection::get_state ()
 	root->add_property ("name", name);
 	child = root->add_child ("Playlists");
 
-	for (list<Playlist*>::iterator i = playlists.begin(); i != playlists.end(); ++i) {
+	for (PlaylistList::iterator i = playlists.begin(); i != playlists.end(); ++i) {
 		XMLNode* plnode = new XMLNode ("Playlist");
 
 		plnode->add_property ("name", (*i)->name());
diff --git a/libs/ardour/playlist.cc b/libs/ardour/playlist.cc
index 77aee9392d..8c1c608e1b 100644
--- a/libs/ardour/playlist.cc
+++ b/libs/ardour/playlist.cc
@@ -36,6 +36,7 @@
 #include <ardour/session.h>
 #include <ardour/region.h>
 #include <ardour/region_factory.h>
+#include <ardour/playlist_factory.h>
 
 #include "i18n.h"
 
@@ -43,14 +44,12 @@ using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
 
-sigc::signal<void,Playlist*> Playlist::PlaylistCreated;
-
 struct ShowMeTheList {
-    ShowMeTheList (Playlist *pl, const string& n) : playlist (pl), name (n) {}
+    ShowMeTheList (boost::shared_ptr<Playlist> pl, const string& n) : playlist (pl), name (n) {}
     ~ShowMeTheList () { 
 	    cerr << ">>>>" << name << endl; playlist->dump(); cerr << "<<<<" << name << endl << endl; 
     };
-    Playlist *playlist;
+    boost::shared_ptr<Playlist> playlist;
     string name;
 };
 
@@ -86,43 +85,42 @@ Playlist::Playlist (Session& sess, const XMLNode& node, bool hide)
 	init (hide);
 	_name = "unnamed"; /* reset by set_state */
 
-	/* derived class calls set_state() */
+	/* set state called by derived class */
 }
 
-Playlist::Playlist (const Playlist& other, string namestr, bool hide)
-	: _name (namestr), _session (other._session), _orig_diskstream_id(other._orig_diskstream_id)
+Playlist::Playlist (boost::shared_ptr<const Playlist> other, string namestr, bool hide)
+	: _name (namestr), _session (other->_session), _orig_diskstream_id(other->_orig_diskstream_id)
 {
 	init (hide);
 
 	RegionList tmp;
-	other.copy_regions (tmp);
+	other->copy_regions (tmp);
 	
 	in_set_state++;
 
 	for (list<boost::shared_ptr<Region> >::iterator x = tmp.begin(); x != tmp.end(); ++x) {
-		add_region_internal( (*x), (*x)->position() );
+		add_region_internal( (*x), (*x)->position());
 	}
 
 	in_set_state--;
 
-	_splicing  = other._splicing;
-	_nudging   = other._nudging;
-	_edit_mode = other._edit_mode;
+	_splicing  = other->_splicing;
+	_nudging   = other->_nudging;
+	_edit_mode = other->_edit_mode;
 
 	in_set_state = 0;
 	in_flush = false;
 	in_partition = false;
 	subcnt = 0;
 	_read_data_count = 0;
-	_frozen = other._frozen;
-	
-	layer_op_counter = other.layer_op_counter;
-	freeze_length = other.freeze_length;
+	_frozen = other->_frozen;
 	
+	layer_op_counter = other->layer_op_counter;
+	freeze_length = other->freeze_length;
 }
 
-Playlist::Playlist (const Playlist& other, nframes_t start, nframes_t cnt, string str, bool hide)
-	: _name (str), _session (other._session), _orig_diskstream_id(other._orig_diskstream_id)
+Playlist::Playlist (boost::shared_ptr<const Playlist> other, nframes_t start, nframes_t cnt, string str, bool hide)
+	: _name (str), _session (other->_session), _orig_diskstream_id(other->_orig_diskstream_id)
 {
 	RegionLock rlock2 (&((Playlist&)other));
 	
@@ -130,7 +128,7 @@ Playlist::Playlist (const Playlist& other, nframes_t start, nframes_t cnt, strin
 
 	init (hide);
 
-	for (RegionList::const_iterator i = other.regions.begin(); i != other.regions.end(); i++) {
+	for (RegionList::const_iterator i = other->regions.begin(); i != other->regions.end(); i++) {
 
 		boost::shared_ptr<Region> region;
 		boost::shared_ptr<Region> new_region;
@@ -177,32 +175,28 @@ Playlist::Playlist (const Playlist& other, nframes_t start, nframes_t cnt, strin
 
 		new_region = RegionFactory::RegionFactory::create (region, offset, len, new_name, region->layer(), region->flags());
 
-		add_region_internal (new_region, position, true);
+		add_region_internal (new_region, position);
 	}
 	
 	/* this constructor does NOT notify others (session) */
 }
 
 void
-Playlist::ref ()
+Playlist::use ()
 {
 	++_refcnt;
-	InUse (this, true); /* EMIT SIGNAL */
+	InUse (true); /* EMIT SIGNAL */
 }
 
 void
-Playlist::unref ()
+Playlist::release ()
 {
 	if (_refcnt > 0) {
 		_refcnt--; 
 	}
+
 	if (_refcnt == 0) {
-		InUse (this, false); /* EMIT SIGNAL */
-		
-		if (_hidden) {
-			/* nobody knows we exist */
-			delete this;
-		}
+		InUse (false); /* EMIT SIGNAL */
 	}
 }
 
@@ -259,7 +253,7 @@ Playlist::~Playlist ()
 		RegionLock rl (this);
 
 		for (set<boost::shared_ptr<Region> >::iterator i = all_regions.begin(); i != all_regions.end(); ++i) {
-			(*i)->set_playlist (0);
+			(*i)->set_playlist (boost::shared_ptr<Playlist>());
 		}
 	}
 
@@ -460,7 +454,7 @@ Playlist::add_region (boost::shared_ptr<Region> region, nframes_t position, floa
 	nframes_t pos = position;
 	
 	if (itimes >= 1) {
-		add_region_internal (region, pos, true);
+		add_region_internal (region, pos);
 		pos += region->length();
 		--itimes;
 	}
@@ -477,7 +471,7 @@ Playlist::add_region (boost::shared_ptr<Region> region, nframes_t position, floa
 
 	for (int i = 0; i < itimes; ++i) {
 		boost::shared_ptr<Region> copy = RegionFactory::create (region);
-		add_region_internal (copy, pos, true);
+		add_region_internal (copy, pos);
 		pos += region->length();
 	}
 	
@@ -486,12 +480,24 @@ Playlist::add_region (boost::shared_ptr<Region> region, nframes_t position, floa
 		string name;
 		_session.region_name (name, region->name(), false);
 		boost::shared_ptr<Region> sub = RegionFactory::create (region, 0, length, name, region->layer(), region->flags());
-		add_region_internal (sub, pos, true);
+		add_region_internal (sub, pos);
+	}
+}
+
+void
+Playlist::set_region_ownership ()
+{
+	RegionLock rl (this);
+	RegionList::iterator i;
+	boost::weak_ptr<Playlist> pl (shared_from_this());
+
+	for (i = regions.begin(); i != regions.end(); ++i) {
+		(*i)->set_playlist (pl);
 	}
 }
 
 void
-Playlist::add_region_internal (boost::shared_ptr<Region> region, nframes_t position, bool delay_sort)
+Playlist::add_region_internal (boost::shared_ptr<Region> region, nframes_t position)
 {
 	RegionSortByPosition cmp;
 	nframes_t old_length = 0;
@@ -500,7 +506,11 @@ Playlist::add_region_internal (boost::shared_ptr<Region> region, nframes_t posit
 		 old_length = _get_maximum_extent();
 	}
 
-	region->set_playlist (this);
+	if (!in_set_state) {
+		boost::shared_ptr<Playlist> foo (shared_from_this());
+		region->set_playlist (boost::weak_ptr<Playlist>(foo));
+	}
+
 	region->set_position (position, this);
 
 	timestamp_layer_op (region);
@@ -553,7 +563,7 @@ Playlist::remove_region (boost::shared_ptr<Region> region)
 }
 
 int
-Playlist::remove_region_internal (boost::shared_ptr<Region>region, bool delay_sort)
+Playlist::remove_region_internal (boost::shared_ptr<Region>region)
 {
 	RegionList::iterator i;
 	nframes_t old_length = 0;
@@ -687,7 +697,7 @@ Playlist::partition_internal (nframes_t start, nframes_t end, bool cutting, Regi
 				_session.region_name (new_name, current->name(), false);
 				region = RegionFactory::create (current, pos2 - pos1, pos3 - pos2, new_name,
 						       regions.size(), Region::Flag(current->flags()|Region::Automatic|Region::LeftOfSplit|Region::RightOfSplit));
-				add_region_internal (region, start, true);
+				add_region_internal (region, start);
 				new_regions.push_back (region);
 			}
 			
@@ -697,7 +707,7 @@ Playlist::partition_internal (nframes_t start, nframes_t end, bool cutting, Regi
 			region = RegionFactory::create (current, pos3 - pos1, pos4 - pos3, new_name, 
 					       regions.size(), Region::Flag(current->flags()|Region::Automatic|Region::RightOfSplit));
 
-			add_region_internal (region, end, true);
+			add_region_internal (region, end);
 			new_regions.push_back (region);
 
 		        /* "front" ***** */
@@ -726,7 +736,7 @@ Playlist::partition_internal (nframes_t start, nframes_t end, bool cutting, Regi
 				_session.region_name (new_name, current->name(), false);
 				region = RegionFactory::create (current, pos2 - pos1, pos4 - pos2, new_name, (layer_t) regions.size(),
 						       Region::Flag(current->flags()|Region::Automatic|Region::LeftOfSplit));
-				add_region_internal (region, start, true);
+				add_region_internal (region, start);
 				new_regions.push_back (region);
 			}
 
@@ -760,7 +770,7 @@ Playlist::partition_internal (nframes_t start, nframes_t end, bool cutting, Regi
 				 _session.region_name (new_name, current->name(), false);
 				 region = RegionFactory::create (current, 0, pos3 - pos1, new_name,
 							regions.size(), Region::Flag(current->flags()|Region::Automatic|Region::RightOfSplit));
-				 add_region_internal (region, pos1, true);
+				 add_region_internal (region, pos1);
 				 new_regions.push_back (region);
 			} 
 			
@@ -802,20 +812,19 @@ Playlist::partition_internal (nframes_t start, nframes_t end, bool cutting, Regi
 	}
 }
 
-Playlist*
-Playlist::cut_copy (Playlist* (Playlist::*pmf)(nframes_t, nframes_t,bool), list<AudioRange>& ranges, bool result_is_hidden)
+boost::shared_ptr<Playlist>
+Playlist::cut_copy (boost::shared_ptr<Playlist> (Playlist::*pmf)(nframes_t, nframes_t,bool), list<AudioRange>& ranges, bool result_is_hidden)
 {
-	Playlist* ret;
-	Playlist* pl;
+	boost::shared_ptr<Playlist> ret;
+	boost::shared_ptr<Playlist> pl;
 	nframes_t start;
 
 	if (ranges.empty()) {
-		return 0;
+		return boost::shared_ptr<Playlist>();
 	}
 
 	start = ranges.front().start;
 
-
 	for (list<AudioRange>::iterator i = ranges.begin(); i != ranges.end(); ++i) {
 
 		pl = (this->*pmf)((*i).start, (*i).length(), result_is_hidden);
@@ -829,39 +838,31 @@ Playlist::cut_copy (Playlist* (Playlist::*pmf)(nframes_t, nframes_t,bool), list<
 			   chopped.
 			*/
 
-			ret->paste (*pl, (*i).start - start, 1.0f);
-			delete pl;
+			ret->paste (pl, (*i).start - start, 1.0f);
 		}
 	}
 
-	if (ret) {
-		/* manually notify session of new playlist here
-		   because the playlists were constructed without notifying 
-		*/
-		PlaylistCreated (ret);
-	}
-	
 	return ret;
 }
 
-Playlist*
+boost::shared_ptr<Playlist>
 Playlist::cut (list<AudioRange>& ranges, bool result_is_hidden)
 {
-	Playlist* (Playlist::*pmf)(nframes_t,nframes_t,bool) = &Playlist::cut;
+	boost::shared_ptr<Playlist> (Playlist::*pmf)(nframes_t,nframes_t,bool) = &Playlist::cut;
 	return cut_copy (pmf, ranges, result_is_hidden);
 }
 
-Playlist*
+boost::shared_ptr<Playlist>
 Playlist::copy (list<AudioRange>& ranges, bool result_is_hidden)
 {
-	Playlist* (Playlist::*pmf)(nframes_t,nframes_t,bool) = &Playlist::copy;
+	boost::shared_ptr<Playlist> (Playlist::*pmf)(nframes_t,nframes_t,bool) = &Playlist::copy;
 	return cut_copy (pmf, ranges, result_is_hidden);
 }
 
-Playlist *
+boost::shared_ptr<Playlist>
 Playlist::cut (nframes_t start, nframes_t cnt, bool result_is_hidden)
 {
-	Playlist *the_copy;
+	boost::shared_ptr<Playlist> the_copy;
 	RegionList thawlist;
 	char buf[32];
 
@@ -870,8 +871,8 @@ Playlist::cut (nframes_t start, nframes_t cnt, bool result_is_hidden)
 	new_name += '.';
 	new_name += buf;
 
-	if ((the_copy = copyPlaylist (*this, start, cnt, new_name, result_is_hidden)) == 0) {
-		return 0;
+	if ((the_copy = PlaylistFactory::create (shared_from_this(), start, cnt, new_name, result_is_hidden)) == 0) {
+		return boost::shared_ptr<Playlist>();
 	}
 
 	partition_internal (start, start+cnt-1, true, thawlist);
@@ -884,7 +885,7 @@ Playlist::cut (nframes_t start, nframes_t cnt, bool result_is_hidden)
 	return the_copy;
 }
 
-Playlist *
+boost::shared_ptr<Playlist>
 Playlist::copy (nframes_t start, nframes_t cnt, bool result_is_hidden)
 {
 	char buf[32];
@@ -895,28 +896,28 @@ Playlist::copy (nframes_t start, nframes_t cnt, bool result_is_hidden)
 	new_name += buf;
 
 	cnt = min (_get_maximum_extent() - start, cnt);
-	return copyPlaylist (*this, start, cnt, new_name, result_is_hidden);
+	return PlaylistFactory::create (shared_from_this(), start, cnt, new_name, result_is_hidden);
 }
 
 int
-Playlist::paste (Playlist& other, nframes_t position, float times)
+Playlist::paste (boost::shared_ptr<Playlist> other, nframes_t position, float times)
 {
 	times = fabs (times);
 	nframes_t old_length;
 
 	{
 		RegionLock rl1 (this);
-		RegionLock rl2 (&other);
+		RegionLock rl2 (other.get());
 
 		old_length = _get_maximum_extent();
 	
 		int itimes = (int) floor (times);
 		nframes_t pos = position;
-		nframes_t shift = other._get_maximum_extent();
+		nframes_t shift = other->_get_maximum_extent();
 		layer_t top_layer = regions.size();
 
 		while (itimes--) {
-			for (RegionList::iterator i = other.regions.begin(); i != other.regions.end(); ++i) {
+			for (RegionList::iterator i = other->regions.begin(); i != other->regions.end(); ++i) {
 				boost::shared_ptr<Region> copy_of_region = RegionFactory::create (*i);
 
 				/* put these new regions on top of all existing ones, but preserve
@@ -955,7 +956,7 @@ Playlist::duplicate (boost::shared_ptr<Region> region, nframes_t position, float
 
 	while (itimes--) {
 		boost::shared_ptr<Region> copy = RegionFactory::create (region);
-		add_region_internal (copy, pos, true);
+		add_region_internal (copy, pos);
 		pos += region->length();
 	}
 
@@ -964,7 +965,7 @@ Playlist::duplicate (boost::shared_ptr<Region> region, nframes_t position, float
 		string name;
 		_session.region_name (name, region->name(), false);
 		boost::shared_ptr<Region> sub = RegionFactory::create (region, 0, length, name, region->layer(), region->flags());
-		add_region_internal (sub, pos, true);
+		add_region_internal (sub, pos);
 	}
 }
 
@@ -999,7 +1000,7 @@ Playlist::split_region (boost::shared_ptr<Region> region, nframes_t playlist_pos
 	_session.region_name (after_name, region->name(), false);
 	right = RegionFactory::create (region, before, after, after_name, region->layer(), Region::Flag (region->flags()|Region::RightOfSplit));
 
-	add_region_internal (left, region->position(), true);
+	add_region_internal (left, region->position());
 	add_region_internal (right, region->position() + before);
 	
 	uint64_t orig_layer_op = region->last_layer_op();
@@ -1016,7 +1017,7 @@ Playlist::split_region (boost::shared_ptr<Region> region, nframes_t playlist_pos
 
 	finalize_split_region (region, left, right);
 	
-	if (remove_region_internal (region, true)) {
+	if (remove_region_internal (region)) {
 		return;
 	}
 }
diff --git a/libs/ardour/playlist_factory.cc b/libs/ardour/playlist_factory.cc
index 4461783874..f5f19d5b5b 100644
--- a/libs/ardour/playlist_factory.cc
+++ b/libs/ardour/playlist_factory.cc
@@ -22,24 +22,75 @@
 
 #include <ardour/playlist.h>
 #include <ardour/audioplaylist.h>
+#include <ardour/playlist_factory.h>
 
 #include "i18n.h"
 
 using namespace ARDOUR;
 using namespace PBD;
 
-Playlist*
-Playlist::copyPlaylist (const Playlist& playlist, nframes_t start, nframes_t length,
-			string name, bool result_is_hidden)
+sigc::signal<void,boost::shared_ptr<Playlist> > PlaylistFactory::PlaylistCreated;
+
+boost::shared_ptr<Playlist> 
+PlaylistFactory::create (Session& s, const XMLNode& node, bool hidden) 
+{
+	boost::shared_ptr<Playlist> pl;
+
+	pl = boost::shared_ptr<Playlist> (new AudioPlaylist (s, node, hidden));
+
+	pl->set_region_ownership ();
+
+	if (!hidden) {
+		PlaylistCreated (pl);
+	}
+	return pl;
+}
+
+boost::shared_ptr<Playlist> 
+PlaylistFactory::create (Session& s, string name, bool hidden) 
+{
+	boost::shared_ptr<Playlist> pl;
+
+	pl = boost::shared_ptr<Playlist> (new AudioPlaylist (s, name, hidden));
+
+	if (!hidden) {
+		PlaylistCreated (pl);
+	}
+
+	return pl;
+}
+
+boost::shared_ptr<Playlist> 
+PlaylistFactory::create (boost::shared_ptr<const Playlist> old, string name, bool hidden) 
 {
-	const AudioPlaylist* apl;
-
-	if ((apl = dynamic_cast<const AudioPlaylist*> (&playlist)) != 0) {
-		return new AudioPlaylist (*apl, start, length, name, result_is_hidden);
-	} else {
-		fatal << _("programming error: Playlist::copyPlaylist called with unknown Playlist type")
-		      << endmsg;
-		/*NOTREACHED*/
-		return 0;
+	boost::shared_ptr<Playlist> pl;
+	boost::shared_ptr<const AudioPlaylist> apl;
+
+	if ((apl = boost::dynamic_pointer_cast<const AudioPlaylist> (old)) != 0) {
+		pl = boost::shared_ptr<Playlist> (new AudioPlaylist (apl, name, hidden));
+		pl->set_region_ownership ();
 	}
+
+	if (!hidden) {
+		PlaylistCreated (pl);
+	}
+
+	return pl;
+}
+
+boost::shared_ptr<Playlist> 
+PlaylistFactory::create (boost::shared_ptr<const Playlist> old, nframes_t start, nframes_t cnt, string name, bool hidden) 
+{
+	boost::shared_ptr<Playlist> pl;
+	boost::shared_ptr<const AudioPlaylist> apl;
+	
+	if ((apl = boost::dynamic_pointer_cast<const AudioPlaylist> (old)) != 0) {
+		pl = boost::shared_ptr<Playlist> (new AudioPlaylist (apl, start, cnt, name, hidden));
+		pl->set_region_ownership ();
+	}
+
+
+	/* this factory method does NOT notify others */
+
+	return pl;
 }
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index 5aeecca0e2..9d81cc5907 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -54,7 +54,6 @@ Region::Region (nframes_t start, nframes_t length, const string& name, layer_t l
 	/* basic Region constructor */
 
 	_flags = flags;
-	_playlist = 0;
 	_read_data_count = 0;
 	_frozen = 0;
 	pending_changed = Change (0);
@@ -76,7 +75,6 @@ Region::Region (boost::shared_ptr<const Region> other, nframes_t offset, nframes
 
 	_frozen = 0;
 	pending_changed = Change (0);
-	_playlist = 0;
 	_read_data_count = 0;
 
 	_start = other->_start + offset; 
@@ -100,7 +98,6 @@ Region::Region (boost::shared_ptr<const Region> other)
 
 	_frozen = 0;
 	pending_changed = Change (0);
-	_playlist = 0;
 	_read_data_count = 0;
 
 	_first_edit = EditChangesID;
@@ -126,7 +123,6 @@ Region::Region (const XMLNode& node)
 {
 	_frozen = 0;
 	pending_changed = Change (0);
-	_playlist = 0;
 	_read_data_count = 0;
 	_start = 0; 
 	_sync_position = _start;
@@ -148,7 +144,7 @@ Region::~Region ()
 }
 
 void
-Region::set_playlist (Playlist* pl)
+Region::set_playlist (boost::weak_ptr<Playlist> pl)
 {
 	_playlist = pl;
 }
@@ -206,9 +202,11 @@ Region::maybe_uncopy ()
 void
 Region::first_edit ()
 {
-	if (_first_edit != EditChangesNothing && _playlist) {
+	boost::shared_ptr<Playlist> pl (playlist());
 
-		_name = _playlist->session().new_region_name (_name);
+	if (_first_edit != EditChangesNothing && pl) {
+
+		_name = pl->session().new_region_name (_name);
 		_first_edit = EditChangesNothing;
 
 		send_change (NameChanged);
@@ -219,7 +217,9 @@ Region::first_edit ()
 bool
 Region::at_natural_position () const
 {
-	if (!_playlist) {
+	boost::shared_ptr<Playlist> pl (playlist());
+
+	if (!pl) {
 		return false;
 	}
 	
@@ -237,7 +237,9 @@ Region::at_natural_position () const
 void
 Region::move_to_natural_position (void *src)
 {
-	if (!_playlist) {
+	boost::shared_ptr<Playlist> pl (playlist());
+
+	if (!pl) {
 		return;
 	}
 	
@@ -297,7 +299,11 @@ Region::set_position_on_top (nframes_t pos, void *src)
 		_position = pos;
 	}
 
-	_playlist->raise_region_to_top (shared_from_this ());
+	boost::shared_ptr<Playlist> pl (playlist());
+
+	if (pl) {
+		pl->raise_region_to_top (shared_from_this ());
+	}
 
 	/* do this even if the position is the same. this helps out
 	   a GUI that has moved its representation already.
@@ -684,42 +690,37 @@ Region::sync_position() const
 void
 Region::raise ()
 {
-	if (_playlist == 0) {
-		return;
+	boost::shared_ptr<Playlist> pl (playlist());
+	if (pl) {
+		pl->raise_region (shared_from_this ());
 	}
-
-	_playlist->raise_region (shared_from_this ());
 }
 
 void
 Region::lower ()
 {
-	if (_playlist == 0) {
-		return;
+	boost::shared_ptr<Playlist> pl (playlist());
+	if (pl) {
+		pl->lower_region (shared_from_this ());
 	}
-
-	_playlist->lower_region (shared_from_this ());
 }
 
 void
 Region::raise_to_top ()
 {
-
-	if (_playlist == 0) {
-		return;
+	boost::shared_ptr<Playlist> pl (playlist());
+	if (pl) {
+		pl->raise_region_to_top (shared_from_this());
 	}
-
-	_playlist->raise_region_to_top (shared_from_this());
 }
 
 void
 Region::lower_to_bottom ()
 {
-	if (_playlist == 0) {
-		return;
+	boost::shared_ptr<Playlist> pl (playlist());
+	if (pl) {
+		pl->lower_region_to_bottom (shared_from_this());
 	}
-
-	_playlist->lower_region_to_bottom (shared_from_this());
 }
 
 void
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 14c5bde996..caea881383 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -468,10 +468,24 @@ Session::~Session ()
 		tmp = i;
 		++tmp;
 
-		delete *i;
+		(*i)->drop_references ();
+		
+		i = tmp;
+	}
+	
+	for (PlaylistList::iterator i = unused_playlists.begin(); i != unused_playlists.end(); ) {
+		PlaylistList::iterator tmp;
+
+		tmp = i;
+		++tmp;
+
+		(*i)->drop_references ();
 		
 		i = tmp;
 	}
+	
+	playlists.clear ();
+	unused_playlists.clear ();
 
 #ifdef TRACK_DESTRUCTION
 	cerr << "delete audio regions\n";
@@ -918,7 +932,7 @@ Session::hookup_io ()
 }
 
 void
-Session::playlist_length_changed (Playlist* pl)
+Session::playlist_length_changed ()
 {
 	/* we can't just increase end_location->end() if pl->get_maximum_extent() 
 	   if larger. if the playlist used to be the longest playlist,
@@ -932,10 +946,10 @@ Session::playlist_length_changed (Playlist* pl)
 void
 Session::diskstream_playlist_changed (boost::shared_ptr<Diskstream> dstream)
 {
-	Playlist *playlist;
+	boost::shared_ptr<Playlist> playlist;
 
 	if ((playlist = dstream->playlist()) != 0) {
-	  playlist->LengthChanged.connect (sigc::bind (mem_fun (this, &Session::playlist_length_changed), playlist));
+		playlist->LengthChanged.connect (mem_fun (this, &Session::playlist_length_changed));
 	}
 	
 	/* see comment in playlist_length_changed () */
@@ -2268,7 +2282,7 @@ Session::get_maximum_extent () const
 	boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 
 	for (DiskstreamList::const_iterator i = dsl->begin(); i != dsl->end(); ++i) {
-		Playlist* pl = (*i)->playlist();
+		boost::shared_ptr<Playlist> pl = (*i)->playlist();
 		if ((me = pl->get_maximum_extent()) > max) {
 			max = me;
 		}
@@ -2671,17 +2685,11 @@ Session::add_source (boost::shared_ptr<Source> source)
 			result = audio_sources.insert (entry);
 		}
 
-		if (!result.second) {
-			cerr << "\tNOT inserted ? " << result.second << endl;
+		if (result.second) {
+			source->GoingAway.connect (sigc::bind (mem_fun (this, &Session::remove_source), boost::weak_ptr<Source> (source)));
+			set_dirty();
 		}
-
-		source->GoingAway.connect (sigc::bind (mem_fun (this, &Session::remove_source), boost::weak_ptr<Source> (source)));
-		set_dirty();
-		
-		SourceAdded (source); /* EMIT SIGNAL */
-	} else {
-		cerr << "\tNOT AUDIO FILE\n";
-	}
+	} 
 }
 
 void
@@ -2710,8 +2718,6 @@ Session::remove_source (boost::weak_ptr<Source> src)
 		
 		save_state (_current_snapshot_name);
 	}
-	
-	SourceRemoved(source); /* EMIT SIGNAL */
 }
 
 boost::shared_ptr<Source>
@@ -2897,6 +2903,7 @@ Session::audio_path_from_name (string name, uint32_t nchan, uint32_t chan, bool
 				} else {
 					snprintf (buf, sizeof(buf), "%s/T%04d-%s.wav", spath.c_str(), cnt, legalized.c_str());
 				}
+
 			} else {
 
 				spath += '/';
@@ -2940,6 +2947,7 @@ Session::audio_path_from_name (string name, uint32_t nchan, uint32_t chan, bool
 	string foo = buf;
 
 	spath = discover_best_sound_dir ();
+	spath += '/';
 
 	string::size_type pos = foo.find_last_of ('/');
 	
@@ -2961,7 +2969,7 @@ Session::create_audio_source_for_session (AudioDiskstream& ds, uint32_t chan, bo
 
 /* Playlist management */
 
-Playlist *
+boost::shared_ptr<Playlist>
 Session::playlist_by_name (string name)
 {
 	Glib::Mutex::Lock lm (playlist_lock);
@@ -2975,11 +2983,12 @@ Session::playlist_by_name (string name)
 			return* i;
 		}
 	}
-	return 0;
+
+	return boost::shared_ptr<Playlist>();
 }
 
 void
-Session::add_playlist (Playlist* playlist)
+Session::add_playlist (boost::shared_ptr<Playlist> playlist)
 {
 	if (playlist->hidden()) {
 		return;
@@ -2989,9 +2998,8 @@ Session::add_playlist (Playlist* playlist)
 		Glib::Mutex::Lock lm (playlist_lock);
 		if (find (playlists.begin(), playlists.end(), playlist) == playlists.end()) {
 			playlists.insert (playlists.begin(), playlist);
-			// playlist->ref();
-			playlist->InUse.connect (mem_fun (*this, &Session::track_playlist));
-			playlist->GoingAway.connect (sigc::bind (mem_fun (*this, &Session::remove_playlist), playlist));
+			playlist->InUse.connect (sigc::bind (mem_fun (*this, &Session::track_playlist), boost::weak_ptr<Playlist>(playlist)));
+			playlist->GoingAway.connect (sigc::bind (mem_fun (*this, &Session::remove_playlist), boost::weak_ptr<Playlist>(playlist)));
 		}
 	}
 
@@ -3001,7 +3009,7 @@ Session::add_playlist (Playlist* playlist)
 }
 
 void
-Session::get_playlists (vector<Playlist*>& s)
+Session::get_playlists (vector<boost::shared_ptr<Playlist> >& s)
 {
 	{ 
 		Glib::Mutex::Lock lm (playlist_lock);
@@ -3015,15 +3023,25 @@ Session::get_playlists (vector<Playlist*>& s)
 }
 
 void
-Session::track_playlist (Playlist* pl, bool inuse)
+Session::track_playlist (bool inuse, boost::weak_ptr<Playlist> wpl)
 {
+	boost::shared_ptr<Playlist> pl(wpl.lock());
+
+	if (!pl) {
+		return;
+	}
+
 	PlaylistList::iterator x;
 
+	if (pl->hidden()) {
+		/* its not supposed to be visible */
+		return;
+	}
+
 	{ 
 		Glib::Mutex::Lock lm (playlist_lock);
 
 		if (!inuse) {
-			//cerr << "shifting playlist to unused: " << pl->name() << endl;
 
 			unused_playlists.insert (pl);
 			
@@ -3033,8 +3051,7 @@ Session::track_playlist (Playlist* pl, bool inuse)
 
 			
 		} else {
-			//cerr << "shifting playlist to used: " << pl->name() << endl;
-			
+
 			playlists.insert (pl);
 			
 			if ((x = unused_playlists.find (pl)) != unused_playlists.end()) {
@@ -3045,26 +3062,33 @@ Session::track_playlist (Playlist* pl, bool inuse)
 }
 
 void
-Session::remove_playlist (Playlist* playlist)
+Session::remove_playlist (boost::weak_ptr<Playlist> weak_playlist)
 {
 	if (_state_of_the_state & Deletion) {
 		return;
 	}
 
+	boost::shared_ptr<Playlist> playlist (weak_playlist.lock());
+
+	if (!playlist) {
+		return;
+	}
+
 	{ 
 		Glib::Mutex::Lock lm (playlist_lock);
-		// cerr << "removing playlist: " << playlist->name() << endl;
+		cerr << "removing playlist: " << playlist->name() << endl;
 
 		PlaylistList::iterator i;
 
 		i = find (playlists.begin(), playlists.end(), playlist);
-
 		if (i != playlists.end()) {
+			cerr << "\tfound it in used playlist\n";
 			playlists.erase (i);
 		}
 
 		i = find (unused_playlists.begin(), unused_playlists.end(), playlist);
 		if (i != unused_playlists.end()) {
+			cerr << "\tfound it in unused playlist\n";
 			unused_playlists.erase (i);
 		}
 		
@@ -3617,7 +3641,7 @@ Session::write_one_audio_track (AudioTrack& track, nframes_t start, nframes_t le
 			       bool overwrite, vector<boost::shared_ptr<AudioSource> >& srcs, InterThreadInfo& itt)
 {
 	int ret = -1;
-	Playlist* playlist;
+	boost::shared_ptr<Playlist> playlist;
 	boost::shared_ptr<AudioFileSource> fsource;
 	uint32_t x;
 	char buf[PATH_MAX+1];
diff --git a/libs/ardour/session_command.cc b/libs/ardour/session_command.cc
index 3d2da887b0..06ed44f722 100644
--- a/libs/ardour/session_command.cc
+++ b/libs/ardour/session_command.cc
@@ -70,8 +70,9 @@ Command *Session::memento_command_factory(XMLNode *n)
     } else if (obj_T == typeid (TempoMap).name()) {
 	    return new MementoCommand<TempoMap>(*_tempo_map, before, after);
     } else if (obj_T == typeid (Playlist).name() || obj_T == typeid (AudioPlaylist).name()) {
-	    if (Playlist *pl = playlist_by_name(child->property("name")->value()))
-		    return new MementoCommand<Playlist>(*pl, before, after);
+	    if (boost::shared_ptr<Playlist> pl = playlist_by_name(child->property("name")->value())) {
+		    return new MementoCommand<Playlist>(*(pl.get()), before, after);
+	    }
     } else if (obj_T == typeid (Route).name() || obj_T == typeid (AudioTrack).name()) { 
 	    return new MementoCommand<Route>(*route_by_id(id), before, after);
     } else if (obj_T == typeid (Curve).name() || obj_T == typeid (AutomationList).name()) {
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 95449d6c1a..2ae8a833e1 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -83,6 +83,7 @@
 #include <ardour/control_protocol_manager.h>
 #include <ardour/region_factory.h>
 #include <ardour/source_factory.h>
+#include <ardour/playlist_factory.h>
 
 #include <control_protocol/control_protocol.h>
 
@@ -236,7 +237,7 @@ Session::first_stage_init (string fullpath, string snapshot_name)
 
 	RegionFactory::CheckNewRegion.connect (mem_fun (*this, &Session::add_region));
 	SourceFactory::SourceCreated.connect (mem_fun (*this, &Session::add_source));
-	Playlist::PlaylistCreated.connect (mem_fun (*this, &Session::add_playlist));
+	PlaylistFactory::PlaylistCreated.connect (mem_fun (*this, &Session::add_playlist));
 	Redirect::RedirectCreated.connect (mem_fun (*this, &Session::add_redirect));
 	NamedSelection::NamedSelectionCreated.connect (mem_fun (*this, &Session::add_named_selection));
         AutomationList::AutomationListCreated.connect (mem_fun (*this, &Session::add_automation_list));
@@ -380,6 +381,7 @@ Session::setup_raid_path (string path)
 		if (fspath[fspath.length()-1] != '/') {
 			fspath += '/';
 		}
+
 		fspath += sound_dir (false);
 		
 		AudioFileSource::set_search_path (fspath);
@@ -1681,7 +1683,7 @@ Session::load_playlists (const XMLNode& node)
 {
 	XMLNodeList nlist;
 	XMLNodeConstIterator niter;
-	Playlist *playlist;
+	boost::shared_ptr<Playlist> playlist;
 
 	nlist = node.children();
 
@@ -1702,7 +1704,7 @@ Session::load_unused_playlists (const XMLNode& node)
 {
 	XMLNodeList nlist;
 	XMLNodeConstIterator niter;
-	Playlist *playlist;
+	boost::shared_ptr<Playlist> playlist;
 
 	nlist = node.children();
 
@@ -1717,22 +1719,22 @@ Session::load_unused_playlists (const XMLNode& node)
 
 		// now manually untrack it
 
-		track_playlist (playlist, false);
+		track_playlist (false, boost::weak_ptr<Playlist> (playlist));
 	}
 
 	return 0;
 }
 
 
-Playlist *
+boost::shared_ptr<Playlist>
 Session::XMLPlaylistFactory (const XMLNode& node)
 {
 	try {
-		return new AudioPlaylist (*this, node);
+		return PlaylistFactory::create (*this, node);
 	}
 
 	catch (failed_constructor& err) {
-		return 0;
+		return boost::shared_ptr<Playlist>();
 	}
 }
 
@@ -1792,7 +1794,6 @@ Session::sound_dir (bool with_path) const
 	
 	old_withpath = _path;
 	old_withpath += old_sound_dir_name;
-	old_withpath += '/';
 
 	if (stat (old_withpath.c_str(), &statbuf) == 0) {
 		if (with_path)
@@ -1812,7 +1813,6 @@ Session::sound_dir (bool with_path) const
 	res += legalize_for_path (_name);
 	res += '/';
 	res += sound_dir_name;
-	res += '/';
 
 	return res;
 }
@@ -2385,11 +2385,22 @@ Session::find_all_sources_across_snapshots (set<string>& result, bool exclude_th
 	return 0;
 }
 
+struct RegionCounter {
+    typedef std::map<PBD::ID,boost::shared_ptr<AudioSource> > AudioSourceList;
+    AudioSourceList::iterator iter;
+    boost::shared_ptr<Region> region;
+    uint32_t count;
+    
+    RegionCounter() : count (0) {}
+};
+
 int
 Session::cleanup_sources (Session::cleanup_report& rep)
 {
-	vector<boost::shared_ptr<Source> > dead_sources;
-	vector<Playlist*> playlists_tbd;
+	typedef map<boost::shared_ptr<Source>, RegionCounter> SourceRegionMap;
+	SourceRegionMap dead_sources;
+
+	vector<boost::shared_ptr<Playlist> > playlists_tbd;
 	PathScanner scanner;
 	string sound_path;
 	vector<space_and_path>::iterator i;
@@ -2428,74 +2439,114 @@ Session::cleanup_sources (Session::cleanup_report& rep)
 
 	/* now delete any that were marked for deletion */
 
-	for (vector<Playlist*>::iterator x = playlists_tbd.begin(); x != playlists_tbd.end(); ++x) {
-		PlaylistList::iterator foo;
-
-		if ((foo = unused_playlists.find (*x)) != unused_playlists.end()) {
-			unused_playlists.erase (foo);
-		}
-		delete *x;
+	for (vector<boost::shared_ptr<Playlist> >::iterator x = playlists_tbd.begin(); x != playlists_tbd.end(); ++x) {
+		(*x)->drop_references ();
 	}
 
+	playlists_tbd.clear ();
+
 	/* step 2: find all un-referenced sources */
 
 	rep.paths.clear ();
 	rep.space = 0;
 
-	for (AudioSourceList::iterator i = audio_sources.begin(); i != audio_sources.end(); ) {
-
-		AudioSourceList::iterator tmp;
-
-		tmp = i;
-		++tmp;
+	for (AudioSourceList::iterator i = audio_sources.begin(); i != audio_sources.end(); ++i) {
+		
+		/* we expect the use_count() to be at least 2: one for the shared_ptr<> in the sources
+		   list and one for the iterator. if its used by 1 region, we'd expect a value of 3.
 
-		/* only remove files that are not in use and have some size
-		   to them. otherwise we remove the current "nascent"
+		   do not bother with files that are zero size, otherwise we remove the current "nascent"
 		   capture files.
 		*/
 
-		cerr << "checking out source " << i->second->name() << " use_count = " << i->second.use_count() << endl;
+		if (i->second.use_count() <= 3 && i->second->length() > 0) {
 
-		if (i->second.use_count() == 1 && i->second->length() > 0) {
-			dead_sources.push_back (i->second);
+			pair<boost::shared_ptr<Source>, RegionCounter> newpair;
 
-			/* remove this source from our own list to avoid us
-			   adding it to the list of all sources below
-			*/
-
-			audio_sources.erase (i);
-		}
+			newpair.first = i->second;
+			newpair.second.iter = i;
 
-		i = tmp;
+			dead_sources.insert (newpair);
+		} 
 	}
 
-	/* Step 3: get rid of all regions in the region list that use any dead sources
-	   in case the sources themselves don't go away (they might be referenced in
-	   other snapshots).
-	*/
-		
-	for (vector<boost::shared_ptr<Source> >::iterator i = dead_sources.begin(); i != dead_sources.end();++i) {
+	/* Search the region list to find out the state of the supposedly unreferenced regions 
+	 */
 
-		for (AudioRegionList::iterator r = audio_regions.begin(); r != audio_regions.end(); ) {
-			AudioRegionList::iterator tmp;
-			boost::shared_ptr<AudioRegion> ar;
+	for (SourceRegionMap::iterator i = dead_sources.begin(); i != dead_sources.end();++i) {
 
-			tmp = r;
-			++tmp;
+		for (AudioRegionList::iterator r = audio_regions.begin(); r != audio_regions.end(); ++r) {
 			
-			ar = r->second;
+			boost::shared_ptr<AudioRegion> ar = r->second;
 
 			for (uint32_t n = 0; n < ar->n_channels(); ++n) {
-				if (ar->source (n) == (*i)) {
-					/* this region is dead */
-					remove_region (ar);
+
+				if (ar->source (n) == i->first) {
+					
+					/* this region uses this source */
+
+					i->second.region = ar;
+					i->second.count++;
+
+					if (i->second.count > 1) {
+						break;
+					}
 				}
 			}
-			
-			r = tmp;
 		}
 	}
 
+	/* next, get rid of all regions in the region list that use any dead sources
+	   in case the sources themselves don't go away (they might be referenced in
+	   other snapshots).
+
+	   this is also where we remove the apparently unused sources from our source
+	   list. this doesn't rename them or delete them, but it means they are
+	   potential candidates for renaming after we find all soundfiles
+	   and scan for use across all snapshots (including this one).
+	*/
+	
+	for (SourceRegionMap::iterator i = dead_sources.begin(); i != dead_sources.end(); ) {
+
+		SourceRegionMap::iterator tmp;
+
+		tmp = i;
+		++tmp;
+
+		if (i->second.count == 0) {
+
+			/* no regions use this source */
+
+			/* remove this source from our own list to avoid us
+			   adding it to the list of all sources below
+			*/
+
+			audio_sources.erase (i->second.iter);
+
+ 		} else if (i->second.count == 1) {
+
+			/* the use_count for the source was 3. this means that there is only reference to it in addition to the source
+			   list and an iterator used to traverse that list. since there is a single region using the source, that
+			   must be the extra reference. this implies that its a whole-file region
+			   with no children, so remove the region and the source.
+			*/
+
+			remove_region (i->second.region);
+
+			/* remove this source from our own list to avoid us
+			   adding it to the list of all sources below
+			*/
+
+			audio_sources.erase (i->second.iter);
+
+		} else {
+			/* more than one region uses this source, do not remove it */
+			dead_sources.erase (i);
+		}
+
+		i = tmp;
+	}
+
 	/* build a list of all the possible sound directories for the session */
 
 	for (i = session_dirs.begin(); i != session_dirs.end(); ) {
@@ -2504,7 +2555,7 @@ Session::cleanup_sources (Session::cleanup_report& rep)
 		++nexti;
 
 		sound_path += (*i).path;
-		sound_path += sound_dir_name;
+		sound_path += sound_dir (false);
 
 		if (nexti != session_dirs.end()) {
 			sound_path += ':';
@@ -2512,7 +2563,7 @@ Session::cleanup_sources (Session::cleanup_report& rep)
 
 		i = nexti;
 	}
-	
+
 	/* now do the same thing for the files that ended up in the sounds dir(s) 
 	   but are not referenced as sources in any snapshot.
 	*/
@@ -2577,8 +2628,12 @@ Session::cleanup_sources (Session::cleanup_report& rep)
 		   on whichever filesystem it was already on.
 		*/
 
-		newpath = Glib::path_get_dirname (*x);
-		newpath = Glib::path_get_dirname (newpath);
+		/* XXX this is a hack ... go up 4 levels */
+
+		newpath = Glib::path_get_dirname (*x);      // "audiofiles" 
+		newpath = Glib::path_get_dirname (newpath); // "session-name"
+		newpath = Glib::path_get_dirname (newpath); // "interchange"
+		newpath = Glib::path_get_dirname (newpath); // "session-dir"
 
 		newpath += '/';
 		newpath += dead_sound_dir_name;
@@ -2639,7 +2694,6 @@ Session::cleanup_sources (Session::cleanup_report& rep)
 				goto out;
 			}
 		}
-
 	}
 
 	ret = 0;
diff --git a/libs/ardour/source.cc b/libs/ardour/source.cc
index 74ca0afcd4..39a83cb6de 100644
--- a/libs/ardour/source.cc
+++ b/libs/ardour/source.cc
@@ -110,15 +110,22 @@ Source::set_state (const XMLNode& node)
 }
 
 void
-Source::add_playlist (Playlist* pl)
+Source::add_playlist (boost::shared_ptr<Playlist> pl)
 {
 	_playlists.insert (pl);
+	pl->GoingAway.connect (bind (mem_fun (*this, &Source::remove_playlist), boost::weak_ptr<Playlist> (pl)));
 }
 
 void
-Source::remove_playlist (Playlist* pl)
+Source::remove_playlist (boost::weak_ptr<Playlist> wpl)
 {
-	std::set<Playlist*>::iterator x;
+	boost::shared_ptr<Playlist> pl (wpl.lock());
+
+	if (!pl) {
+		return;
+	}
+
+	std::set<boost::shared_ptr<Playlist> >::iterator x;
 
 	if ((x = _playlists.find (pl)) != _playlists.end()) {
 		_playlists.erase (x);
diff --git a/libs/ardour/source_factory.cc b/libs/ardour/source_factory.cc
index cb36d3cc35..9b8382c39f 100644
--- a/libs/ardour/source_factory.cc
+++ b/libs/ardour/source_factory.cc
@@ -83,10 +83,13 @@ boost::shared_ptr<Source>
 SourceFactory::create (Session& s, const XMLNode& node)
 {
 	boost::shared_ptr<Source> ret (new SndFileSource (s, node));
+
 	if (setup_peakfile (ret)) {
 		return boost::shared_ptr<Source>();
 	}
+
 	SourceCreated (ret);
+
 	return ret;
 }
 
@@ -141,12 +144,15 @@ boost::shared_ptr<Source>
 SourceFactory::createReadable (Session& s, string idstr, AudioFileSource::Flag flags, bool announce)
 {
 	boost::shared_ptr<Source> ret (new SndFileSource (s, idstr, flags));
+
 	if (setup_peakfile (ret)) {
 		return boost::shared_ptr<Source>();
 	}
+
 	if (announce) {
 		SourceCreated (ret);
 	}
+
 	return ret;
 }