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, 18 insertions, 4 deletions

diff --git a/libs/pbd/stateful_diff_command.cc b/libs/pbd/stateful_diff_command.cc
index 635fe4829a..2c58acee14 100644
--- a/libs/pbd/stateful_diff_command.cc
+++ b/libs/pbd/stateful_diff_command.cc
@@ -32,15 +32,21 @@ using namespace PBD;
  *  @param s Stateful object.
  */
 
-StatefulDiffCommand::StatefulDiffCommand (boost::shared_ptr<Stateful> s)
-	: _object (s)
+StatefulDiffCommand::StatefulDiffCommand (boost::shared_ptr<StatefulDestructible> s)
+        : _object (s)
         , _undo (new PropertyList)
         , _redo (new PropertyList)
 {
-        s->diff (*_undo, *_redo);
+        s->diff (*_undo, *_redo, this);
+
+        /* if the stateful object that this command refers to goes away,
+           be sure to notify owners of this command.
+        */
+
+        s->DropReferences.connect_same_thread (*this, boost::bind (&Destructible::drop_references, this));
 }
 
-StatefulDiffCommand::StatefulDiffCommand (boost::shared_ptr<Stateful> s, XMLNode const & n)
+StatefulDiffCommand::StatefulDiffCommand (boost::shared_ptr<StatefulDestructible> s, XMLNode const & n)
 	: _object (s)
         , _undo (0)
         , _redo (0)
@@ -57,10 +63,18 @@ StatefulDiffCommand::StatefulDiffCommand (boost::shared_ptr<Stateful> s, XMLNode
 
         assert (_undo != 0);
         assert (_redo != 0);
+
+        /* if the stateful object that this command refers to goes away,
+           be sure to notify owners of this command.
+        */
+
+        s->DropReferences.connect_same_thread (*this, boost::bind (&Destructible::drop_references, this));
 }
 
 StatefulDiffCommand::~StatefulDiffCommand ()
 {
+        drop_references ();
+
         delete _undo;
         delete _redo;
 }