midway snapshot of work done on managing Region & Source lifetimes correctly. may fix missing MIDI file bug ; save empty playlists because they may be referred to by the history file ; undo commands auto-delete when objects they refer to die (currently not commands built from XML deserialization); Sources now know how many regions are using them for something, meaning that we know if we can delete the files holding any data for the source

git-svn-id: svn://localhost/ardour2/branches/3.0@7291 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 12 insertions, 0 deletions

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 ();