Sort various things to reduce merge hell. No functional changes.
[ardour.git] / libs / ardour / playlist.cc
index 7a87033a56351e7f880914e557e489ac74683a28..da3a812123b0744cb1b1526b5eac7a4e5ef2965b 100644 (file)
@@ -15,7 +15,6 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
-    $Id$
 */
 
 #include <set>
 #include <pbd/failed_constructor.h>
 #include <pbd/stl_delete.h>
 #include <pbd/xml++.h>
+#include <pbd/stacktrace.h>
 
 #include <ardour/playlist.h>
 #include <ardour/session.h>
 #include <ardour/region.h>
 #include <ardour/region_factory.h>
+#include <ardour/playlist_factory.h>
+#include <ardour/transient_detector.h>
 
 #include "i18n.h"
 
@@ -43,14 +45,12 @@ 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;
 };
 
@@ -72,68 +72,74 @@ struct RegionSortByLastLayerOp {
     }
 };
 
-Playlist::Playlist (Session& sess, string nom, bool hide)
-       : _session (sess)
+
+Playlist::Playlist (Session& sess, string nom, DataType type, bool hide)
+       : SessionObject(sess, nom)
+       , _type(type)
 {
        init (hide);
+       first_set_state = false;
        _name = nom;
        
 }
 
-Playlist::Playlist (Session& sess, const XMLNode& node, bool hide)
-       : _session (sess)
+Playlist::Playlist (Session& sess, const XMLNode& node, DataType type, bool hide)
+       : SessionObject(sess, "unnamed playlist")
+       , _type(type)
 {
+       const XMLProperty* prop = node.property("type");
+       assert(!prop || DataType(prop->value()) == _type);
+
        init (hide);
        _name = "unnamed"; /* reset by set_state */
-       
-       if (set_state (node)) {
-               throw failed_constructor();
-       }
+
+       /* 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)
+       : SessionObject(other->_session, namestr), _type(other->_type), _orig_diskstream_id(other->_orig_diskstream_id)
 {
        init (hide);
 
        RegionList tmp;
-       other.copy_regions (tmp);
+       other->copy_regions (tmp);
        
-       in_set_state = true;
+       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 = false;
+       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 = false;
+       in_set_state = 0;
+       first_set_state = false;
        in_flush = false;
        in_partition = false;
        subcnt = 0;
        _read_data_count = 0;
-       _frozen = other._frozen;
-       save_on_thaw = false;
-       
-       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)
+       : SessionObject(other->_session, str), _type(other->_type), _orig_diskstream_id(other->_orig_diskstream_id)
 {
-       RegionLock rlock2 (&((Playlist&)other));
-       
+       RegionLock rlock2 (const_cast<Playlist*> (other.get()));
+
        nframes_t end = start + cnt - 1;
 
        init (hide);
 
-       for (RegionList::const_iterator i = other.regions.begin(); i != other.regions.end(); i++) {
+       in_set_state++;
+
+       for (RegionList::const_iterator i = other->regions.begin(); i != other->regions.end(); i++) {
 
                boost::shared_ptr<Region> region;
                boost::shared_ptr<Region> new_region;
@@ -180,36 +186,34 @@ 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);
        }
        
+       in_set_state--;
+       first_set_state = false;
+
        /* 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 */
        }
 }
 
-
 void
 Playlist::copy_regions (RegionList& newlist) const
 {
@@ -227,18 +231,19 @@ Playlist::init (bool hide)
        g_atomic_int_set (&ignore_state_changes, 0);
        pending_modified = false;
        pending_length = false;
+       first_set_state = true;
        _refcnt = 0;
        _hidden = hide;
        _splicing = false;
+       _shuffling = false;
        _nudging = false;
-       in_set_state = false;
+       in_set_state = 0;
        _edit_mode = Config->get_edit_mode();
        in_flush = false;
        in_partition = false;
        subcnt = 0;
        _read_data_count = 0;
        _frozen = false;
-       save_on_thaw = false;
        layer_op_counter = 0;
        freeze_length = 0;
 
@@ -246,23 +251,33 @@ Playlist::init (bool hide)
 }
 
 Playlist::Playlist (const Playlist& pl)
-       : _session (pl._session)
+       : SessionObject(pl._session, pl._name)
+       , _type(pl.data_type())
 {
        fatal << _("playlist const copy constructor called") << endmsg;
 }
 
 Playlist::Playlist (Playlist& pl)
-       : _session (pl._session)
+       : SessionObject(pl._session, pl._name)
+       , _type(pl.data_type())
 {
        fatal << _("playlist non-const copy constructor called") << endmsg;
 }
 
 Playlist::~Playlist ()
 {
+       { 
+               RegionLock rl (this);
+
+               for (set<boost::shared_ptr<Region> >::iterator i = all_regions.begin(); i != all_regions.end(); ++i) {
+                       (*i)->set_playlist (boost::shared_ptr<Playlist>());
+               }
+       }
+
        /* GoingAway must be emitted by derived classes */
 }
 
-void
+bool
 Playlist::set_name (const string& str)
 {
        /* in a typical situation, a playlist is being used
@@ -272,11 +287,10 @@ Playlist::set_name (const string& str)
        */
 
        if (_refcnt > 2) {
-               return;
+               return false;
+       } else {
+               return SessionObject::set_name(str);
        }
-
-       _name = str; 
-       NameChanged(); /* EMIT SIGNAL */
 }
 
 /***********************************************************************
@@ -333,13 +347,16 @@ void
 Playlist::notify_region_removed (boost::shared_ptr<Region> r)
 {
        if (holding_state ()) {
-               pending_removals.insert (pending_removals.end(), r);
+               pending_removes.insert (r);
+               pending_modified = true;
+               pending_length = true;
        } else {
-               RegionRemoved (r); /* EMIT SIGNAL */
                /* this might not be true, but we have to act
                   as though it could be.
                */
+               pending_length = false;
                LengthChanged (); /* EMIT SIGNAL */
+               pending_modified = false;
                Modified (); /* EMIT SIGNAL */
        }
 }
@@ -347,14 +364,18 @@ Playlist::notify_region_removed (boost::shared_ptr<Region> r)
 void
 Playlist::notify_region_added (boost::shared_ptr<Region> r)
 {
+       /* the length change might not be true, but we have to act
+          as though it could be.
+       */
+
        if (holding_state()) {
-               pending_adds.insert (pending_adds.end(), r);
+               pending_adds.insert (r);
+               pending_modified = true;
+               pending_length = true;
        } else {
-               RegionAdded (r); /* EMIT SIGNAL */
-               /* this might not be true, but we have to act
-                  as though it could be.
-               */
+               pending_length = false;
                LengthChanged (); /* EMIT SIGNAL */
+               pending_modified = false;
                Modified (); /* EMIT SIGNAL */
        }
 }
@@ -365,7 +386,9 @@ Playlist::notify_length_changed ()
        if (holding_state ()) {
                pending_length = true;
        } else {
+               pending_length = false;
                LengthChanged(); /* EMIT SIGNAL */
+               pending_modified = false;
                Modified (); /* EMIT SIGNAL */
        }
 }
@@ -373,9 +396,8 @@ Playlist::notify_length_changed ()
 void
 Playlist::flush_notifications ()
 {
-       RegionList::iterator r;
-       RegionList::iterator a;
        set<boost::shared_ptr<Region> > dependent_checks_needed;
+       set<boost::shared_ptr<Region> >::iterator s;
        uint32_t n = 0;
 
        if (in_flush) {
@@ -398,27 +420,17 @@ Playlist::flush_notifications ()
                        timestamp_layer_op (*r);
                }
                pending_length = true;
-               n++;
-       }
-
-       for (RegionList::iterator r = pending_bounds.begin(); r != pending_bounds.end(); ++r) {
                dependent_checks_needed.insert (*r);
-               /* don't increment n again - its the same list */
-       }
-
-       for (a = pending_adds.begin(); a != pending_adds.end(); ++a) {
-               dependent_checks_needed.insert (*a);
-               RegionAdded (*a); /* EMIT SIGNAL */
                n++;
        }
 
-       for (set<boost::shared_ptr<Region> >::iterator x = dependent_checks_needed.begin(); x != dependent_checks_needed.end(); ++x) {
-               check_dependents (*x, false);
+       for (s = pending_adds.begin(); s != pending_adds.end(); ++s) {
+               dependent_checks_needed.insert (*s);
+               n++;
        }
 
-       for (r = pending_removals.begin(); r != pending_removals.end(); ++r) {
-               remove_dependents (*r);
-               RegionRemoved (*r); /* EMIT SIGNAL */
+       for (s = pending_removes.begin(); s != pending_removes.end(); ++s) {
+               remove_dependents (*s);
                n++;
        }
 
@@ -430,22 +442,21 @@ Playlist::flush_notifications ()
 
        if (n || pending_modified) {
                if (!in_set_state) {
-                       possibly_splice ();
                        relayer ();
                }
                pending_modified = false;
                Modified (); /* EMIT SIGNAL */
+               
+       }
+
+       for (s = dependent_checks_needed.begin(); s != dependent_checks_needed.end(); ++s) {
+               check_dependents (*s, false);
        }
 
        pending_adds.clear ();
-       pending_removals.clear ();
+       pending_removes.clear ();
        pending_bounds.clear ();
 
-       if (save_on_thaw) {
-               save_on_thaw = false;
-               save_state (last_save_reason);
-       }
-       
        in_flush = false;
 }
 
@@ -454,10 +465,10 @@ Playlist::flush_notifications ()
  *************************************************************/
 
 void
-Playlist::add_region (boost::shared_ptr<Region> region, nframes_t position, float times, bool with_save
+Playlist::add_region (boost::shared_ptr<Region> region, nframes_t position, float times) 
 { 
        RegionLock rlock (this);
-       
+       delay_notifications();
        times = fabs (times);
        
        int itimes = (int) floor (times);
@@ -465,42 +476,51 @@ 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;
        }
        
-       /* later regions will all be spliced anyway */
        
-       if (!holding_state ()) {
-               possibly_splice_unlocked ();
-       }
-
        /* note that itimes can be zero if we being asked to just
           insert a single fraction of the region.
        */
 
        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();
        }
        
+       nframes_t length = 0;
+
        if (floor (times) != times) {
-               nframes_t length = (nframes_t) floor (region->length() * (times - floor (times)));
+               length = (nframes_t) floor (region->length() * (times - floor (times)));
                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);
        }
-       
-       if (with_save) {
-               maybe_save_state (_("add region"));
+
+
+       possibly_splice_unlocked (position, (pos + length) - position, boost::shared_ptr<Region>());
+       release_notifications ();
+}
+
+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;
@@ -509,12 +529,19 @@ Playlist::add_region_internal (boost::shared_ptr<Region> region, nframes_t posit
                 old_length = _get_maximum_extent();
        }
 
-       region->set_playlist (this);
+       if (!first_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);
 
        regions.insert (upper_bound (regions.begin(), regions.end(), region, cmp), region);
+       all_regions.insert (region);
+
+       possibly_splice_unlocked (position, region->length(), region);
 
        if (!holding_state () && !in_set_state) {
                /* layers get assigned from XML state */
@@ -532,7 +559,8 @@ Playlist::add_region_internal (boost::shared_ptr<Region> region, nframes_t posit
                }
        }
 
-       region->StateChanged.connect (sigc::bind (mem_fun (this, &Playlist::region_changed_proxy), region));
+       region->StateChanged.connect (sigc::bind (mem_fun (this, &Playlist::region_changed_proxy), 
+                                                 boost::weak_ptr<Region> (region)));
 }
 
 void
@@ -540,14 +568,15 @@ Playlist::replace_region (boost::shared_ptr<Region> old, boost::shared_ptr<Regio
 {
        RegionLock rlock (this);
 
+       bool old_sp = _splicing;
+       _splicing = true;
+
        remove_region_internal (old);
        add_region_internal (newr, pos);
 
-       if (!holding_state ()) {
-               possibly_splice_unlocked ();
-       }
+       _splicing = old_sp;
 
-       maybe_save_state (_("replace region"));
+       possibly_splice_unlocked (pos, (nframes64_t) old->length() - (nframes64_t) newr->length());
 }
 
 void
@@ -555,31 +584,33 @@ Playlist::remove_region (boost::shared_ptr<Region> region)
 {
        RegionLock rlock (this);
        remove_region_internal (region);
-
-       if (!holding_state ()) {
-               possibly_splice_unlocked ();
-       }
-
-       maybe_save_state (_("remove 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;
 
-       // cerr << "removing region " << region->name() << endl;
-
        if (!holding_state()) {
                old_length = _get_maximum_extent();
        }
 
+       if (!in_set_state) {
+               /* unset playlist */
+               region->set_playlist (boost::weak_ptr<Playlist>());
+       }
+
        for (i = regions.begin(); i != regions.end(); ++i) {
                if (*i == region) {
 
+                       nframes_t pos = (*i)->position();
+                       nframes64_t distance = (*i)->length();
+
                        regions.erase (i);
 
+                       possibly_splice_unlocked (pos, -distance);
+
                        if (!holding_state ()) {
                                relayer ();
                                remove_dependents (region);
@@ -593,17 +624,24 @@ Playlist::remove_region_internal (boost::shared_ptr<Region>region, bool delay_so
                        return 0;
                }
        }
+
+
+
        return -1;
 }
 
 void
 Playlist::get_equivalent_regions (boost::shared_ptr<Region> other, vector<boost::shared_ptr<Region> >& results)
 {
-       for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
-               if (Config->get_use_overlap_equivalency()) {
+       if (Config->get_use_overlap_equivalency()) {
+               for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
                        if ((*i)->overlap_equivalent (other)) {
                                results.push_back ((*i));
-                       } else if ((*i)->equivalent (other)) {
+                       }
+               }
+       } else {
+               for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
+                       if ((*i)->equivalent (other)) {
                                results.push_back ((*i));
                        }
                }
@@ -631,8 +669,6 @@ Playlist::partition (nframes_t start, nframes_t end, bool just_top_level)
        for (RegionList::iterator i = thawlist.begin(); i != thawlist.end(); ++i) {
                (*i)->thaw ("separation");
        }
-
-       maybe_save_state (_("separate"));
 }
 
 void
@@ -702,7 +738,7 @@ 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);
                        }
                        
@@ -712,7 +748,7 @@ 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" ***** */
@@ -741,7 +777,7 @@ 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);
                        }
 
@@ -775,7 +811,7 @@ 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);
                        } 
                        
@@ -817,20 +853,19 @@ 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);
@@ -844,39 +879,31 @@ 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];
 
@@ -885,23 +912,20 @@ 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);
-       possibly_splice ();
 
        for (RegionList::iterator i = thawlist.begin(); i != thawlist.end(); ++i) {
                (*i)->thaw ("playlist cut");
        }
 
-       maybe_save_state (_("cut"));
-
        return the_copy;
 }
 
-Playlist *
+boost::shared_ptr<Playlist>
 Playlist::copy (nframes_t start, nframes_t cnt, bool result_is_hidden)
 {
        char buf[32];
@@ -912,28 +936,28 @@ 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
@@ -946,7 +970,6 @@ Playlist::paste (Playlist& other, nframes_t position, float times)
                        pos += shift;
                }
 
-               possibly_splice_unlocked ();
 
                /* XXX shall we handle fractional cases at some point? */
 
@@ -957,8 +980,6 @@ Playlist::paste (Playlist& other, nframes_t position, float times)
                
        }
 
-       maybe_save_state (_("paste"));
-
        return 0;
 }
 
@@ -974,7 +995,7 @@ 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();
        }
 
@@ -983,10 +1004,8 @@ 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);
        }
-
-       maybe_save_state (_("duplicate"));
 }
 
 void
@@ -1010,19 +1029,23 @@ Playlist::split_region (boost::shared_ptr<Region> region, nframes_t playlist_pos
        string before_name;
        string after_name;
 
+       /* split doesn't change anything about length, so don't try to splice */
+       
+       bool old_sp = _splicing;
+       _splicing = true;
+
        before = playlist_position - region->position();
        after = region->length() - before;
        
-       
        _session.region_name (before_name, region->name(), false);
        left = RegionFactory::create (region, 0, before, before_name, region->layer(), Region::Flag (region->flags()|Region::LeftOfSplit));
 
        _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();
        for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
                if ((*i)->last_layer_op() > orig_layer_op) {
@@ -1037,73 +1060,84 @@ Playlist::split_region (boost::shared_ptr<Region> region, nframes_t playlist_pos
 
        finalize_split_region (region, left, right);
        
-       if (remove_region_internal (region, true)) {
-               return;
-       }
+       remove_region_internal (region);
 
-       maybe_save_state (_("split"));
+       _splicing = old_sp;
 }
 
 void
-Playlist::possibly_splice ()
+Playlist::possibly_splice (nframes_t at, nframes64_t distance, boost::shared_ptr<Region> exclude)
 {
+       if (_splicing || in_set_state) {
+               /* don't respond to splicing moves or state setting */
+               return;
+       }
+
        if (_edit_mode == Splice) {
-               splice_locked ();
+               splice_locked (at, distance, exclude);
        }
 }
 
 void
-Playlist::possibly_splice_unlocked ()
+Playlist::possibly_splice_unlocked (nframes_t at, nframes64_t distance, boost::shared_ptr<Region> exclude)
 {
+       if (_splicing || in_set_state) {
+               /* don't respond to splicing moves or state setting */
+               return;
+       }
+
        if (_edit_mode == Splice) {
-               splice_unlocked ();
+               splice_unlocked (at, distance, exclude);
        }
 }
 
 void
-Playlist::splice_locked ()
+Playlist::splice_locked (nframes_t at, nframes64_t distance, boost::shared_ptr<Region> exclude)
 {
        {
                RegionLock rl (this);
-               core_splice ();
+               core_splice (at, distance, exclude);
        }
-
-       notify_length_changed ();
 }
 
 void
-Playlist::splice_unlocked ()
+Playlist::splice_unlocked (nframes_t at, nframes64_t distance, boost::shared_ptr<Region> exclude)
 {
-       core_splice ();
-       notify_length_changed ();
+       core_splice (at, distance, exclude);
 }
 
 void
-Playlist::core_splice ()
+Playlist::core_splice (nframes_t at, nframes64_t distance, boost::shared_ptr<Region> exclude)
 {
        _splicing = true;
-       
+
        for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
-               
-               RegionList::iterator next;
-               
-               next = i;
-               ++next;
-               
-               if (next == regions.end()) {
-                       break;
+
+               if (exclude && (*i) == exclude) {
+                       continue;
+               }
+
+               if ((*i)->position() >= at) {
+                       nframes64_t new_pos = (*i)->position() + distance;
+                       if (new_pos < 0) {
+                               new_pos = 0;
+                       } else if (new_pos >= max_frames - (*i)->length()) {
+                               new_pos = max_frames - (*i)->length();
+                       } 
+                               
+                       (*i)->set_position (new_pos, this);
                }
-               
-               (*next)->set_position ((*i)->last_frame() + 1, this);
        }
-       
+
        _splicing = false;
+
+       notify_length_changed ();
 }
 
 void
 Playlist::region_bounds_changed (Change what_changed, boost::shared_ptr<Region> region)
 {
-       if (in_set_state || _splicing || _nudging) {
+       if (in_set_state || _splicing || _nudging || _shuffling) {
                return;
        }
 
@@ -1126,11 +1160,24 @@ Playlist::region_bounds_changed (Change what_changed, boost::shared_ptr<Region>
 
                regions.erase (i);
                regions.insert (upper_bound (regions.begin(), regions.end(), region, cmp), region);
-
        }
 
        if (what_changed & Change (ARDOUR::PositionChanged|ARDOUR::LengthChanged)) {
-       
+               
+               nframes64_t delta = 0;
+               
+               if (what_changed & ARDOUR::PositionChanged) {
+                       delta = (nframes64_t) region->position() - (nframes64_t) region->last_position();
+               } 
+               
+               if (what_changed & ARDOUR::LengthChanged) {
+                       delta += (nframes64_t) region->length() - (nframes64_t) region->last_length();
+               } 
+
+               if (delta) {
+                       possibly_splice (region->last_position() + region->last_length(), delta, region);
+               }
+
                if (holding_state ()) {
                        pending_bounds.push_back (region);
                } else {
@@ -1139,17 +1186,23 @@ Playlist::region_bounds_changed (Change what_changed, boost::shared_ptr<Region>
                                timestamp_layer_op (region);
                        }
                        
-                       possibly_splice ();
-                       check_dependents (region, false);
                        notify_length_changed ();
                        relayer ();
+                       check_dependents (region, false);
                }
        }
 }
 
 void
-Playlist::region_changed_proxy (Change what_changed, boost::shared_ptr<Region> region)
+Playlist::region_changed_proxy (Change what_changed, boost::weak_ptr<Region> weak_region)
 {
+       boost::shared_ptr<Region> region (weak_region.lock());
+
+       if (!region) {
+               return;
+       }
+
+
        /* this makes a virtual call to the right kind of playlist ... */
 
        region_changed (what_changed, region);
@@ -1171,8 +1224,8 @@ Playlist::region_changed (Change what_changed, boost::shared_ptr<Region> region)
                        save = !(_splicing || _nudging);
                }
                
-               if ((what_changed & Region::MuteChanged) && 
-                   !(what_changed &  Change (ARDOUR::PositionChanged|ARDOUR::LengthChanged))) {
+               if ((what_changed & our_interests) && 
+                   !(what_changed & Change (ARDOUR::PositionChanged|ARDOUR::LengthChanged))) {
                        check_dependents (region, false);
                }
                
@@ -1185,24 +1238,31 @@ Playlist::region_changed (Change what_changed, boost::shared_ptr<Region> region)
 }
 
 void
-Playlist::clear (bool with_save)
+Playlist::drop_regions ()
 {
-       RegionList::iterator i;
-       RegionList tmp;
+       RegionLock rl (this);
+       regions.clear ();
+       all_regions.clear ();
+}
 
+void
+Playlist::clear (bool with_signals)
+{
        { 
                RegionLock rl (this);
-               tmp = regions;
+               for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
+                       pending_removes.insert (*i);
+               }
                regions.clear ();
        }
-       
-       for (i = tmp.begin(); i != tmp.end(); ++i) {
-               notify_region_removed (*i);
-       }
 
-       if (with_save) {
-               maybe_save_state (_("clear"));
+       if (with_signals) {
+               pending_length = false;
+               LengthChanged ();
+               pending_modified = false;
+               Modified ();
        }
+
 }
 
 /***********************************************************************
@@ -1235,9 +1295,114 @@ Playlist::top_region_at (nframes_t frame)
        return region;
 }      
 
+Playlist::RegionList*
+Playlist::regions_to_read (nframes_t start, nframes_t end)
+{
+       /* Caller must hold lock */
+
+       RegionList covering;
+       set<nframes_t> to_check;
+       set<boost::shared_ptr<Region> > unique;
+       RegionList here;
+
+       to_check.insert (start);
+       to_check.insert (end);
+
+       for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
+
+               /* find all/any regions that span start+end */
+
+               switch ((*i)->coverage (start, end)) {
+               case OverlapNone:
+                       break;
+
+               case OverlapInternal:
+                       covering.push_back (*i);
+                       break;
+
+               case OverlapStart:
+                       to_check.insert ((*i)->position());
+                       covering.push_back (*i);
+                       break;
+
+               case OverlapEnd:
+                       to_check.insert ((*i)->last_frame());
+                       covering.push_back (*i);
+                       break;
+
+               case OverlapExternal:
+                       covering.push_back (*i);
+                       to_check.insert ((*i)->position());
+                       to_check.insert ((*i)->last_frame());
+                       break;
+               }
+
+               /* don't go too far */
+
+               if ((*i)->position() > end) {
+                       break;
+               }
+       }
+
+       RegionList* rlist = new RegionList;
+
+       /* find all the regions that cover each position .... */
+
+       if (covering.size() == 1) {
+
+               rlist->push_back (covering.front());
+               
+       } else {
+       
+               for (set<nframes_t>::iterator t = to_check.begin(); t != to_check.end(); ++t) {
+                       
+                       here.clear ();
+                       
+                       for (RegionList::iterator x = covering.begin(); x != covering.end(); ++x) {
+                       
+                               if ((*x)->covers (*t)) {
+                                       here.push_back (*x);
+                               }
+                       }
+                       
+                       RegionSortByLayer cmp;
+                       here.sort (cmp);
+                       
+                       /* ... and get the top/transparent regions at "here" */
+                       
+                       for (RegionList::reverse_iterator c = here.rbegin(); c != here.rend(); ++c) {
+                               
+                               unique.insert (*c);
+                               
+                               if ((*c)->opaque()) {
+                                       
+                                       /* the other regions at this position are hidden by this one */
+                                       
+                                       break;
+                               }
+                       }
+               }
+               
+               for (set<boost::shared_ptr<Region> >::iterator s = unique.begin(); s != unique.end(); ++s) {
+                       rlist->push_back (*s);
+               }
+
+               if (rlist->size() > 1) {
+                       /* now sort by time order */
+                       
+                       RegionSortByPosition cmp;
+                       rlist->sort (cmp);
+               }
+       }
+
+       return rlist;
+}
+
 Playlist::RegionList *
 Playlist::find_regions_at (nframes_t frame)
 {
+       /* Caller must hold lock */
+
        RegionList *rlist = new RegionList;
 
        for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
@@ -1264,6 +1429,65 @@ Playlist::regions_touched (nframes_t start, nframes_t end)
        return rlist;
 }
 
+nframes64_t
+Playlist::find_next_transient (nframes64_t from, int dir)
+{
+       RegionLock rlock (this);
+       AnalysisFeatureList points;
+       AnalysisFeatureList these_points;
+
+       for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
+               if (dir > 0) {
+                       if ((*i)->last_frame() < from) {
+                               continue;
+                       }
+               } else {
+                       if ((*i)->first_frame() > from) {
+                               continue;
+                       }
+               }
+
+               (*i)->get_transients (these_points);
+
+               /* add first frame, just, err, because */
+               
+               these_points.push_back ((*i)->first_frame());
+               
+               points.insert (points.end(), these_points.begin(), these_points.end());
+               these_points.clear ();
+       }
+       
+       if (points.empty()) {
+               return -1;
+       }
+
+       TransientDetector::cleanup_transients (points, _session.frame_rate(), 3.0);
+       bool reached = false;
+       
+       if (dir > 0) {
+               for (AnalysisFeatureList::iterator x = points.begin(); x != points.end(); ++x) {
+                       if ((*x) >= from) {
+                               reached = true;
+                       }
+                       
+                       if (reached && (*x) > from) {
+                               return *x;
+                       }
+               }
+       } else {
+               for (AnalysisFeatureList::reverse_iterator x = points.rbegin(); x != points.rend(); ++x) {
+                       if ((*x) <= from) {
+                               reached = true;
+                       }
+                       
+                       if (reached && (*x) < from) {
+                               return *x;
+                       }
+               }
+       }
+
+       return -1;
+}
 
 boost::shared_ptr<Region>
 Playlist::find_next_region (nframes_t frame, RegionPoint point, int dir)
@@ -1272,6 +1496,7 @@ Playlist::find_next_region (nframes_t frame, RegionPoint point, int dir)
        boost::shared_ptr<Region> ret;
        nframes_t closest = max_frames;
 
+
        for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
 
                nframes_t distance;
@@ -1293,7 +1518,7 @@ Playlist::find_next_region (nframes_t frame, RegionPoint point, int dir)
                switch (dir) {
                case 1: /* forwards */
 
-                       if (pos > frame) {
+                       if (pos >= frame) {
                                if ((distance = pos - frame) < closest) {
                                        closest = distance;
                                        ret = r;
@@ -1304,7 +1529,7 @@ Playlist::find_next_region (nframes_t frame, RegionPoint point, int dir)
 
                default: /* backwards */
 
-                       if (pos < frame) {
+                       if (pos <= frame) {
                                if ((distance = frame - pos) < closest) {
                                        closest = distance;
                                        ret = r;
@@ -1317,6 +1542,92 @@ Playlist::find_next_region (nframes_t frame, RegionPoint point, int dir)
        return ret;
 }
 
+nframes64_t
+Playlist::find_next_region_boundary (nframes64_t frame, int dir)
+{
+       RegionLock rlock (this);
+
+       nframes64_t closest = max_frames;
+       nframes64_t ret = -1;
+
+       if (dir > 0) {
+
+               for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
+                       
+                       boost::shared_ptr<Region> r = (*i);
+                       nframes64_t distance;
+                       nframes64_t end = r->position() + r->length();
+                       bool reset;
+
+                       reset = false;
+
+                       if (r->first_frame() > frame) {
+
+                               distance = r->first_frame() - frame;
+                               
+                               if (distance < closest) {
+                                       ret = r->first_frame();
+                                       closest = distance;
+                                       reset = true;
+                               }
+                       }
+
+                       if (end > frame) {
+                               
+                               distance = end - frame;
+                               
+                               if (distance < closest) {
+                                       ret = end;
+                                       closest = distance;
+                                       reset = true;
+                               }
+                       }
+
+                       if (reset) {
+                               break;
+                       }
+               }
+
+       } else {
+
+               for (RegionList::reverse_iterator i = regions.rbegin(); i != regions.rend(); ++i) {
+                       
+                       boost::shared_ptr<Region> r = (*i);
+                       nframes64_t distance;
+                       bool reset;
+
+                       reset = false;
+
+                       if (r->last_frame() < frame) {
+
+                               distance = frame - r->last_frame();
+                               
+                               if (distance < closest) {
+                                       ret = r->last_frame();
+                                       closest = distance;
+                                       reset = true;
+                               }
+                       }
+
+                       if (r->first_frame() < frame) {
+                               distance = frame - r->last_frame();
+                               
+                               if (distance < closest) {
+                                       ret = r->first_frame();
+                                       closest = distance;
+                                       reset = true;
+                               }
+                       }
+
+                       if (reset) {
+                               break;
+                       }
+               }
+       }
+
+       return ret;
+}
+
 /***********************************************************************/
 
 
@@ -1332,8 +1643,6 @@ Playlist::mark_session_dirty ()
 int
 Playlist::set_state (const XMLNode& node)
 {
-       in_set_state = true;
-
        XMLNode *child;
        XMLNodeList nlist;
        XMLNodeConstIterator niter;
@@ -1343,13 +1652,15 @@ Playlist::set_state (const XMLNode& node)
        boost::shared_ptr<Region> region;
        string region_name;
 
-       clear (false);
+       in_set_state++;
 
        if (node.name() != "Playlist") {
-               in_set_state = false;
+               in_set_state--;
                return -1;
        }
 
+       freeze ();
+
        plist = node.properties();
 
        for (piter = plist.begin(); piter != plist.end(); ++piter) {
@@ -1365,6 +1676,8 @@ Playlist::set_state (const XMLNode& node)
                }
        }
 
+       clear (false);
+       
        nlist = node.children();
 
        for (niter = nlist.begin(); niter != nlist.end(); ++niter) {
@@ -1373,20 +1686,39 @@ Playlist::set_state (const XMLNode& node)
                
                if (child->name() == "Region") {
 
-                       if ((region = RegionFactory::create (_session, *child, true)) == 0) {
-                               error << _("Playlist: cannot create region from state file") << endmsg;
+                       if ((prop = child->property ("id")) == 0) {
+                               error << _("region state node has no ID, ignored") << endmsg;
                                continue;
                        }
+                       
+                       ID id = prop->value ();
+                       
+                       if ((region = region_by_id (id))) {
 
-                       add_region (region, region->position(), 1.0, false);
+                               Change what_changed = Change (0);
+
+                               if (region->set_live_state (*child, what_changed, true)) {
+                                       error << _("Playlist: cannot reset region state from XML") << endmsg;
+                                       continue;
+                               }
+
+                       } else if ((region = RegionFactory::create (_session, *child, true)) == 0) {
+                               error << _("Playlist: cannot create region from XML") << endmsg;
+                               continue;
+                       }
+
+                       add_region (region, region->position(), 1.0);
 
                        // So that layer_op ordering doesn't get screwed up
                        region->set_last_layer_op( region->layer());
 
                }                       
        }
-
        
+       notify_modified ();
+
+       thaw ();
+
        /* update dependents, which was not done during add_region_internal 
           due to in_set_state being true 
        */
@@ -1394,9 +1726,9 @@ Playlist::set_state (const XMLNode& node)
        for (RegionList::iterator r = regions.begin(); r != regions.end(); ++r) {
                check_dependents (*r, false);
        }
-       
-       in_set_state = false;
 
+       in_set_state--;
+       first_set_state = false;
        return 0;
 }
 
@@ -1419,14 +1751,14 @@ Playlist::state (bool full_state)
        char buf[64];
        
        node->add_property (X_("name"), _name);
+       node->add_property (X_("type"), _type.to_string());
 
-       _orig_diskstream_id.print (buf);
+       _orig_diskstream_id.print (buf, sizeof (buf));
        node->add_property (X_("orig_diskstream_id"), buf);
        node->add_property (X_("frozen"), _frozen ? "yes" : "no");
 
        if (full_state) {
                RegionLock rlock (this, false);
-
                for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
                        node->add_child_nocopy ((*i)->get_state());
                }
@@ -1442,17 +1774,25 @@ Playlist::state (bool full_state)
 bool
 Playlist::empty() const
 {
+       RegionLock rlock (const_cast<Playlist *>(this), false);
        return regions.empty();
 }
 
+uint32_t
+Playlist::n_regions() const
+{
+       RegionLock rlock (const_cast<Playlist *>(this), false);
+       return regions.size();
+}
+
 nframes_t
 Playlist::get_maximum_extent () const
 {
-       RegionLock rlock (const_cast<Playlist *>(this));
+       RegionLock rlock (const_cast<Playlist *>(this), false);
        return _get_maximum_extent ();
 }
 
-nframes_t
+ARDOUR::nframes_t
 Playlist::_get_maximum_extent () const
 {
        RegionList::const_iterator i;
@@ -1475,7 +1815,7 @@ Playlist::bump_name (string name, Session &session)
 
        do {
                newname = Playlist::bump_name_once (newname);
-       } while (session.playlist_by_name(newname)!=NULL);
+       } while (session.playlist_by_name (newname)!=NULL);
 
        return newname;
 }
@@ -1487,17 +1827,33 @@ Playlist::bump_name_once (string name)
        string newname;
 
        if ((period = name.find_last_of ('.')) == string::npos) {
-               newname = name;
+               newname  = name;
                newname += ".1";
        } else {
-               char buf[32];
-               int version;
-               
-               sscanf (name.substr (period+1).c_str(), "%d", &version);
-               snprintf (buf, sizeof(buf), "%d", version+1);
+               int isnumber = 1;
+               const char *last_element = name.c_str() + period + 1;
+               for (size_t i = 0; i < strlen(last_element); i++) {
+                       if (!isdigit(last_element[i])) {
+                               isnumber = 0;
+                               break;
+                       }
+               }
+
+               errno = 0;
+               long int version = strtol (name.c_str()+period+1, (char **)NULL, 10);
+
+               if (isnumber == 0 || errno != 0) {
+                       // last_element is not a number, or is too large
+                       newname  = name;
+                       newname += ".1";
+               } else {
+                       char buf[32];
+
+                       snprintf (buf, sizeof(buf), "%ld", version+1);
                
-               newname = name.substr (0, period+1);
-               newname += buf;
+                       newname  = name.substr (0, period+1);
+                       newname += buf;
+               }
        }
 
        return newname;
@@ -1528,33 +1884,65 @@ Playlist::set_edit_mode (EditMode mode)
 void
 Playlist::relayer ()
 {
-       RegionList::iterator i;
-       uint32_t layer = 0;
-
        /* don't send multiple Modified notifications
           when multiple regions are relayered.
        */
-
        freeze ();
 
-       if (Config->get_layer_model() == MoveAddHigher || 
-           Config->get_layer_model() == AddHigher) {
+       /* build up a new list of regions on each layer */
 
-               RegionSortByLastLayerOp cmp;
-               RegionList copy = regions;
+       std::vector<RegionList> layers;
+
+       /* we want to go through regions from desired lowest to desired highest layer,
+          which depends on the layer model
+       */
+
+       RegionList copy = regions;
+
+       /* sort according to the model */
 
+       if (Config->get_layer_model() == MoveAddHigher || Config->get_layer_model() == AddHigher) {
+               RegionSortByLastLayerOp cmp;
                copy.sort (cmp);
+       }
+       
+       for (RegionList::iterator i = copy.begin(); i != copy.end(); ++i) {
 
-               for (i = copy.begin(); i != copy.end(); ++i) {
-                       (*i)->set_layer (layer++);
+               /* find the lowest layer that this region can go on */
+               size_t j = layers.size();
+               while (j > 0) {
+                       /* try layer j - 1; it can go on if it overlaps no other region
+                          that is already on that layer
+                       */
+                       RegionList::iterator k = layers[j - 1].begin();
+                       while (k != layers[j - 1].end()) {
+                               if ((*k)->overlap_equivalent (*i)) {
+                                       break;
+                               }
+                               k++;
+                       }
+
+                       if (k != layers[j - 1].end()) {
+                               /* no overlap, so we can use this layer */
+                               break;
+                       }
+                                       
+                       j--;
                }
 
-       } else {
-               
-               /* Session::LaterHigher model */
+               if (j == layers.size()) {
+                       /* we need a new layer for this region */
+                       layers.push_back (RegionList ());
+               }
 
-               for (i = regions.begin(); i != regions.end(); ++i) {
-                       (*i)->set_layer (layer++);
+               layers[j].push_back (*i);
+       }
+
+       /* first pass: set up the layer numbers in the regions */
+       for (size_t j = 0; j < layers.size(); ++j) {
+               for (RegionList::iterator i = layers[j].begin(); i != layers[j].end(); ++i) {
+                       (*i)->set_layer (j);
                }
        }
 
@@ -1682,6 +2070,7 @@ Playlist::move_region_to_layer (layer_t target_layer, boost::shared_ptr<Region>
 
        region->set_layer (target_layer);
 
+#if 0
        /* now check all dependents */
 
        for (list<LayerInfo>::iterator x = layerinfo.begin(); x != layerinfo.end(); ++x) {
@@ -1689,6 +2078,7 @@ Playlist::move_region_to_layer (layer_t target_layer, boost::shared_ptr<Region>
        }
        
        check_dependents (region, false);
+#endif
        
        return 0;
 }
@@ -1734,7 +2124,6 @@ Playlist::nudge_after (nframes_t start, nframes_t distance, bool forwards)
 
        if (moved) {
                _nudging = false;
-               maybe_save_state (_("nudged"));
                notify_length_changed ();
        }
 
@@ -1744,26 +2133,31 @@ boost::shared_ptr<Region>
 Playlist::find_region (const ID& id) const
 {
        RegionLock rlock (const_cast<Playlist*> (this));
-       RegionList::const_iterator i;
-       boost::shared_ptr<Region> ret;
 
-       for (i = regions.begin(); i != regions.end(); ++i) {
+       /* searches all regions currently in use by the playlist */
+
+       for (RegionList::const_iterator i = regions.begin(); i != regions.end(); ++i) {
                if ((*i)->id() == id) {
-                       ret = *i;
+                       return *i;
                }
        }
 
-       return ret;
+       return boost::shared_ptr<Region> ();
 }
-       
-void
-Playlist::save_state (std::string why)
+
+boost::shared_ptr<Region>
+Playlist::region_by_id (ID id)
 {
-       if (!in_set_state) {
-               StateManager::save_state (why);
+       /* searches all regions ever added to this playlist */
+
+       for (set<boost::shared_ptr<Region> >::iterator i = all_regions.begin(); i != all_regions.end(); ++i) {
+               if ((*i)->id() == id) {
+                       return *i;
+               }
        }
+       return boost::shared_ptr<Region> ();
 }
-
+       
 void
 Playlist::dump () const
 {
@@ -1799,13 +2193,144 @@ Playlist::timestamp_layer_op (boost::shared_ptr<Region> region)
        region->set_last_layer_op (++layer_op_counter);
 }
 
+
 void
-Playlist::maybe_save_state (string why)
+Playlist::shuffle (boost::shared_ptr<Region> region, int dir)
 {
-       if (holding_state ()) {
-               save_on_thaw = true;
-               last_save_reason = why;
-       } else {
-               save_state (why);
+       bool moved = false;
+       nframes_t new_pos;
+
+       if (region->locked()) {
+               return;
+       }
+
+       _shuffling = true;
+
+       {
+               RegionLock rlock (const_cast<Playlist*> (this));
+               
+               
+               if (dir > 0) {
+                       
+                       RegionList::iterator next;
+
+                       for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {       
+                               if ((*i) == region) {
+                                       next = i;
+                                       ++next;
+
+                                       if (next != regions.end()) {
+
+                                               if ((*next)->locked()) {
+                                                       break;
+                                               }
+
+                                               if ((*next)->position() != region->last_frame() + 1) {
+                                                       /* they didn't used to touch, so after shuffle,
+                                                          just have them swap positions.
+                                                       */
+                                                       new_pos = (*next)->position();
+                                               } else {
+                                                       /* they used to touch, so after shuffle,
+                                                          make sure they still do. put the earlier
+                                                          region where the later one will end after
+                                                          it is moved.
+                                                       */
+                                                       new_pos = region->position() + (*next)->length();
+                                               }
+
+                                               (*next)->set_position (region->position(), this);
+                                               region->set_position (new_pos, this);
+
+                                               /* avoid a full sort */
+
+                                               regions.erase (i); // removes the region from the list */
+                                               next++;
+                                               regions.insert (next, region); // adds it back after next
+
+                                               moved = true;
+                                       }
+                                       break;
+                               }
+                       }
+               } else {
+                       
+                       RegionList::iterator prev = regions.end();
+                       
+                       for (RegionList::iterator i = regions.begin(); i != regions.end(); prev = i, ++i) {     
+                               if ((*i) == region) {
+
+                                       if (prev != regions.end()) {
+
+                                               if ((*prev)->locked()) {
+                                                       break;
+                                               }
+
+                                               if (region->position() != (*prev)->last_frame() + 1) {
+                                                       /* they didn't used to touch, so after shuffle,
+                                                          just have them swap positions.
+                                                       */
+                                                       new_pos = region->position();
+                                               } else {
+                                                       /* they used to touch, so after shuffle,
+                                                          make sure they still do. put the earlier
+                                                          one where the later one will end after
+                                                       */
+                                                       new_pos = (*prev)->position() + region->length();
+                                               }
+
+                                               region->set_position ((*prev)->position(), this);
+                                               (*prev)->set_position (new_pos, this);
+                                               
+                                               /* avoid a full sort */
+
+                                               regions.erase (i); // remove region
+                                               regions.insert (prev, region); // insert region before prev
+
+                                               moved = true;
+                                       }
+
+                                       break;
+                               }
+                       }
+               }
+       }
+
+       _shuffling = false;
+
+       if (moved) {
+
+               relayer ();
+               check_dependents (region, false);
+               
+               notify_modified();
        }
+
+}
+
+bool
+Playlist::region_is_shuffle_constrained (boost::shared_ptr<Region>) 
+{
+       RegionLock rlock (const_cast<Playlist*> (this));
+       
+       if (regions.size() > 1) {
+               return true;
+       }
+
+       return false;
+}
+
+void
+Playlist::update_after_tempo_map_change ()
+{
+       RegionLock rlock (const_cast<Playlist*> (this));
+       RegionList copy (regions);
+
+       freeze ();
+       
+       for (RegionList::iterator i = copy.begin(); i != copy.end(); ++i) {     
+               (*i)->update_position_after_tempo_map_change ();
+       }
+
+       thaw ();
 }