9 files changed, 30 insertions, 12 deletions
diff --git a/libs/ardour/ardour/diskstream.h b/libs/ardour/ardour/diskstream.h
index c089a39736..d0d2bcbc36 100644
--- a/libs/ardour/ardour/diskstream.h
+++ b/libs/ardour/ardour/diskstream.h
@@ -45,7 +45,7 @@ namespace ARDOUR {
 class IO;
 class Playlist;
 class Processor;
-class Region;
+class Source;
 class Session;
 class Track;
 class Location;	
@@ -134,12 +134,10 @@ class Diskstream : public SessionObject, public PublicDiskstream
 
 	int set_loop (Location *loc);
 
-	std::list<boost::shared_ptr<Region> >& last_capture_regions () { return _last_capture_regions; }
+	std::list<boost::shared_ptr<Source> >& last_capture_sources () { return _last_capture_sources; }
 
 	void handle_input_change (IOChange, void *src);
 
-	void remove_region_from_last_capture (boost::weak_ptr<Region> wregion);
-
 	void move_processor_automation (boost::weak_ptr<Processor>,
 			std::list<Evoral::RangeMove<framepos_t> > const &);
 
@@ -228,7 +226,7 @@ class Diskstream : public SessionObject, public PublicDiskstream
 
 	virtual bool realtime_set_speed (double, bool global_change);
 
-	std::list<boost::shared_ptr<Region> > _last_capture_regions;
+	std::list<boost::shared_ptr<Source> > _last_capture_sources;
 
 	virtual int use_pending_capture_data (XMLNode& node) = 0;
 
diff --git a/libs/ardour/ardour/playlist.h b/libs/ardour/ardour/playlist.h
index 4b42fc0bd6..7afc074b4d 100644
--- a/libs/ardour/ardour/playlist.h
+++ b/libs/ardour/ardour/playlist.h
@@ -65,7 +65,8 @@ class RegionListProperty : public PBD::SequenceProperty<std::list<boost::shared_
         RegionListProperty (Playlist&);
 
         boost::shared_ptr<Region> lookup_id (const PBD::ID& id);
-        void diff (PBD::PropertyList& undo, PBD::PropertyList& redo) const;
+        void diff (PBD::PropertyList& undo, PBD::PropertyList& redo, Command*) const;
+        bool involves (boost::shared_ptr<Region>);
 
   private:
         friend class Playlist;
diff --git a/libs/ardour/ardour/public_diskstream.h b/libs/ardour/ardour/public_diskstream.h
index c31e88a79b..9e25cb24c6 100755
--- a/libs/ardour/ardour/public_diskstream.h
+++ b/libs/ardour/ardour/public_diskstream.h
@@ -23,7 +23,7 @@
 namespace ARDOUR {
 
 class Playlist;
-class Region;
+class Source;
 class Location;
 
 /** Public interface to a Diskstream */	
@@ -34,7 +34,7 @@ public:
 	virtual boost::shared_ptr<Playlist> playlist () = 0;
 	virtual void monitor_input (bool) = 0;
 	virtual bool destructive () const = 0;
-	virtual std::list<boost::shared_ptr<Region> > & last_capture_regions () = 0;
+	virtual std::list<boost::shared_ptr<Source> > & last_capture_sources () = 0;
 	virtual void set_capture_offset () = 0;
 	virtual void reset_write_sources (bool, bool force = false) = 0;
 	virtual float playback_buffer_load () const = 0;
diff --git a/libs/ardour/ardour/region.h b/libs/ardour/ardour/region.h
index 2cf9bab97b..a30bb8660c 100644
--- a/libs/ardour/ardour/region.h
+++ b/libs/ardour/ardour/region.h
@@ -270,6 +270,8 @@ class Region
 		return _pending_explicit_relayer;
 	}
 
+        void drop_sources ();
+
   protected:
 	friend class RegionFactory;
 
diff --git a/libs/ardour/ardour/region_factory.h b/libs/ardour/ardour/region_factory.h
index c9f387f172..459699d810 100644
--- a/libs/ardour/ardour/region_factory.h
+++ b/libs/ardour/ardour/region_factory.h
@@ -21,6 +21,7 @@
 #define __ardour_region_factory_h__
 
 #include <map>
+#include <set>
 #include <glibmm/thread.h>
 
 #include "pbd/id.h"
@@ -78,7 +79,10 @@ class RegionFactory {
 	/** create a region with specified sources @param srcs and XML state */
 	static boost::shared_ptr<Region> create (SourceList& srcs, const XMLNode&);
 
+        static void get_regions_using_source (boost::shared_ptr<Source>, std::set<boost::shared_ptr<Region> >& );
+
 	static void map_remove (boost::shared_ptr<Region>);
+	static void map_remove_with_equivalents (boost::shared_ptr<Region>);
         static void delete_all_regions ();
         static const RegionMap& regions() { return region_map; }
         static uint32_t nregions ();
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index f7692e09cb..bca65c88e4 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -512,8 +512,7 @@ class Session : public PBD::StatefulDestructible, public PBD::ScopedConnectionLi
 	int  cleanup_sources (CleanupReport&);
 	int  cleanup_trash_sources (CleanupReport&);
 
-	int destroy_region (boost::shared_ptr<Region>);
-	int destroy_regions (std::list<boost::shared_ptr<Region> >);
+	int destroy_sources (std::list<boost::shared_ptr<Source> >);
 
 	int remove_last_capture ();
 
diff --git a/libs/ardour/ardour/session_playlists.h b/libs/ardour/ardour/session_playlists.h
index d654595d60..1c83a312a5 100644
--- a/libs/ardour/ardour/session_playlists.h
+++ b/libs/ardour/ardour/session_playlists.h
@@ -53,6 +53,7 @@ public:
 	template<class T> void foreach (T *obj, void (T::*func)(boost::shared_ptr<Playlist>));
 	void get (std::vector<boost::shared_ptr<Playlist> >&);
 	void unassigned (std::list<boost::shared_ptr<Playlist> > & list);
+        void destroy_region (boost::shared_ptr<Region>);
 
 private:
 	friend class Session;
@@ -69,7 +70,7 @@ private:
 	int load (Session &, const XMLNode&);
 	int load_unused (Session &, const XMLNode&);
 	boost::shared_ptr<Playlist> XMLPlaylistFactory (Session &, const XMLNode&);
-
+        
 	mutable Glib::Mutex lock;
 	typedef std::set<boost::shared_ptr<Playlist> > List;
 	List playlists;
diff --git a/libs/ardour/ardour/source.h b/libs/ardour/ardour/source.h
index bf92e5a6e4..16a762eb94 100644
--- a/libs/ardour/ardour/source.h
+++ b/libs/ardour/ardour/source.h
@@ -23,6 +23,8 @@
 #include <string>
 #include <set>
 
+#include <glib.h>
+
 #include <boost/utility.hpp>
 #include "pbd/statefuldestructible.h"
 
@@ -102,6 +104,15 @@ class Source : public SessionObject
 	Glib::Mutex& mutex()       { return _lock; }
 	Flag         flags() const { return _flags; }
 
+        void inc_use_count () { g_atomic_int_inc (&_use_count); }
+        void dec_use_count () { 
+                gint oldval = g_atomic_int_exchange_and_add (&_use_count, -1);
+                assert (oldval > 0);
+        }
+
+        int  use_count() const { return g_atomic_int_get (&_use_count); }
+        bool used() const { return use_count() > 0; }
+
   protected:
 	DataType            _type;
 	Flag                _flags;
@@ -111,6 +122,7 @@ class Source : public SessionObject
 	mutable Glib::Mutex _lock;
 	mutable Glib::Mutex _analysis_lock;
 	Glib::Mutex         _playlist_lock;
+        gint                _use_count; /* atomic */
 
   private:
 	void fix_writable_flags ();
diff --git a/libs/ardour/ardour/track.h b/libs/ardour/ardour/track.h
index ac948f12df..d72d29e563 100644
--- a/libs/ardour/ardour/track.h
+++ b/libs/ardour/ardour/track.h
@@ -29,6 +29,7 @@ namespace ARDOUR {
 class Session;
 class Playlist;
 class RouteGroup;
+class Source;
 class Region;
 class Diskstream;
 
@@ -100,7 +101,7 @@ class Track : public Route, public PublicDiskstream
 	boost::shared_ptr<Playlist> playlist ();
 	void monitor_input (bool);
 	bool destructive () const;
-	std::list<boost::shared_ptr<Region> > & last_capture_regions ();
+	std::list<boost::shared_ptr<Source> > & last_capture_sources ();
 	void set_capture_offset ();
 	void reset_write_sources (bool, bool force = false);
 	float playback_buffer_load () const;