/*
    Copyright (C) 2000-2003 Paul Davis 

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <iostream>
#include <cmath>
#include <climits>
#include <algorithm>
#include <sstream>

#include <sigc++/bind.h>
#include <sigc++/class_slot.h>

#include <glibmm/thread.h>
#include <pbd/xml++.h>
#include <pbd/stacktrace.h>
#include <pbd/enumwriter.h>

#include <ardour/region.h>
#include <ardour/playlist.h>
#include <ardour/session.h>
#include <ardour/tempo.h>
#include <ardour/region_factory.h>
#include <ardour/profile.h>

#include "i18n.h"

using namespace std;
using namespace ARDOUR;
using namespace PBD;

Change Region::FadeChanged       = ARDOUR::new_change ();
Change Region::SyncOffsetChanged = ARDOUR::new_change ();
Change Region::MuteChanged       = ARDOUR::new_change ();
Change Region::OpacityChanged    = ARDOUR::new_change ();
Change Region::LockChanged       = ARDOUR::new_change ();
Change Region::LayerChanged      = ARDOUR::new_change ();
Change Region::HiddenChanged     = ARDOUR::new_change ();

Region::Region (nframes_t start, nframes_t length, const string& name, layer_t layer, Region::Flag flags)
{
	/* basic Region constructor */

	_flags = flags;
	_read_data_count = 0;
	_frozen = 0;
	pending_changed = Change (0);
	valid_transients = false;
	_name = name;
	_start = start; 
	_sync_position = _start;
	_length = length; 
	_last_length = length; 
	_ancestral_start = 0;  // see comments in various libs/ardour/*_effect.cc
	_ancestral_length = 0; // ditto
	_stretch = 1.0;
	_shift = 1.0;
	_last_position = 0; 
	_position = 0; 
	_layer = layer;
	_read_data_count = 0;
	_first_edit = EditChangesNothing;
	_last_layer_op = 0;
	_positional_lock_style = AudioTime;
}

Region::Region (boost::shared_ptr<const Region> other, nframes_t offset, nframes_t length, const string& name, layer_t layer, Flag flags)
{
	/* create a new Region from part of an existing one */

	_start = other->_start + offset; 

	copy_stuff (other, offset, length, name, layer, flags);

	/* if the other region had a distinct sync point
	   set, then continue to use it as best we can.
	   otherwise, reset sync point back to start.
	*/

	if (other->flags() & SyncMarked) {
		if (other->_sync_position < _start) {
			_flags = Flag (_flags & ~SyncMarked);
			_sync_position = _start;
		} else {
			_sync_position = other->_sync_position;
		}
	} else {
		_flags = Flag (_flags & ~SyncMarked);
		_sync_position = _start;
	}

	if (Profile->get_sae()) {
		/* reset sync point to start if its ended up
		   outside region bounds.
		*/

		if (_sync_position < _start || _sync_position >= _start + _length) {
			_flags = Flag (_flags & ~SyncMarked);
			_sync_position = _start;
		}
	}

}

Region::Region (boost::shared_ptr<const Region> other, nframes_t length, const string& name, layer_t layer, Flag flags)
{
	/* create a new Region exactly like another but starting at 0 in its sources */

	_start = 0;
	copy_stuff (other, 0, length, name, layer, flags);

	/* sync pos is relative to start of file. our start-in-file is now zero,
	   so set our sync position to whatever the the difference between
	   _start and _sync_pos was in the other region. 

	   result is that our new sync pos points to the same point in our source(s) 
	   as the sync in the other region did in its source(s).

	   since we start at zero in our source(s), it is not possible to use a sync point that
	   is before the start. reset it to _start if that was true in the other region.
	*/
	
	if (other->flags() & SyncMarked) {
		if (other->_start < other->_sync_position) {
			/* sync pos was after the start point of the other region */
			_sync_position = other->_sync_position - other->_start;
		} else {
			/* sync pos was before the start point of the other region. not possible here. */
			_flags = Flag (_flags & ~SyncMarked);
			_sync_position = _start;
		}
	} else {
		_flags = Flag (_flags & ~SyncMarked);
		_sync_position = _start;
	}
		
	if (Profile->get_sae()) {
		/* reset sync point to start if its ended up
		   outside region bounds.
		*/

		if (_sync_position < _start || _sync_position >= _start + _length) {
			_flags = Flag (_flags & ~SyncMarked);
			_sync_position = _start;
		}
	}

	/* reset a couple of things that copy_stuff() gets wrong in this particular case */

	_positional_lock_style = other->_positional_lock_style;
	_first_edit = other->_first_edit;
}

void
Region::copy_stuff (boost::shared_ptr<const Region> other, nframes_t offset, nframes_t length, const string& name, layer_t layer, Flag flags)
{
	_frozen = 0;
	pending_changed = Change (0);
	_read_data_count = 0;
	valid_transients = false;

	_length = length; 
	_last_length = length; 
	_sync_position = other->_sync_position;
	_ancestral_start = other->_ancestral_start;
	_ancestral_length = other->_ancestral_length; 
	_stretch = other->_stretch;
	_shift = other->_shift;
	_name = name;
	_last_position = 0; 
	_position = 0; 
	_layer = layer; 
	_flags = Flag (flags & ~(Locked|WholeFile|Hidden));
	_first_edit = EditChangesNothing;
	_last_layer_op = 0;
	_positional_lock_style = AudioTime;
}

Region::Region (boost::shared_ptr<const Region> other)
{
	/* Pure copy constructor */

	_frozen = 0;
	pending_changed = Change (0);
	_read_data_count = 0;
	valid_transients = false;

	_first_edit = EditChangesID;
	other->_first_edit = EditChangesName;

	if (other->_extra_xml) {
		_extra_xml = new XMLNode (*other->_extra_xml);
	} else {
		_extra_xml = 0;
	}

	_start = other->_start;
	_sync_position = other->_sync_position;
	_length = other->_length; 
	_last_length = other->_length; 
	_ancestral_start = other->_ancestral_start; 
	_ancestral_length = other->_ancestral_length; 
	_stretch = other->_stretch;
	_shift = other->_shift;
	_name = other->_name;
	_last_position = other->_position; 
	_position = other->_position; 
	_layer = other->_layer; 
	_flags = Flag (other->_flags & ~Locked);
	_last_layer_op = other->_last_layer_op;
	_positional_lock_style = AudioTime;
}

Region::Region (const XMLNode& node)
{
	_frozen = 0;
	pending_changed = Change (0);
	valid_transients = false;
	_read_data_count = 0;
	_start = 0; 
	_sync_position = _start;
	_length = 0;
	_last_length = 0;
	_name = X_("error: XML did not reset this");
	_last_position = 0; 
	_position = 0; 
	_layer = 0;
	_flags = Flag (0);
	_first_edit = EditChangesNothing;
	_positional_lock_style = AudioTime;

	if (set_state (node)) {
		throw failed_constructor();
	}
}

Region::~Region ()
{
	/* derived classes must call notify_callbacks() and then emit GoingAway */
}

void
Region::set_playlist (boost::weak_ptr<Playlist> pl)
{
	_playlist = pl;
}

void
Region::set_name (string str)
{
	if (_name != str) {
		_name = str; 
		send_change (NameChanged);
	}
}

void
Region::set_length (nframes_t len, void *src)
{
	//cerr << "Region::set_length() len = " << len << endl;
	if (_flags & Locked) {
		return;
	}

	if (_length != len && len != 0) {

		/* check that the current _position wouldn't make the new 
		   length impossible.
		*/

		if (max_frames - len < _position) {
			return;
		}

		if (!verify_length (len)) {
			return;
		}
		

		_last_length = _length;
		_length = len;

		_flags = Region::Flag (_flags & ~WholeFile);

		first_edit ();
		maybe_uncopy ();
		invalidate_transients ();

		if (!_frozen) {
			recompute_at_end ();
		}

		send_change (LengthChanged);
	}
}

void
Region::maybe_uncopy ()
{
}

void
Region::first_edit ()
{
	boost::shared_ptr<Playlist> pl (playlist());

	if (_first_edit != EditChangesNothing && pl) {

		_name = pl->session().new_region_name (_name);
		_first_edit = EditChangesNothing;

		send_change (NameChanged);
		RegionFactory::CheckNewRegion (shared_from_this());
	}
}

bool
Region::at_natural_position () const
{
	boost::shared_ptr<Playlist> pl (playlist());

	if (!pl) {
		return false;
	}
	
	boost::shared_ptr<Region> whole_file_region = get_parent();

	if (whole_file_region) {
		if (_position == whole_file_region->position() + _start) {
			return true;
		}
	}

	return false;
}

void
Region::move_to_natural_position (void *src)
{
	boost::shared_ptr<Playlist> pl (playlist());

	if (!pl) {
		return;
	}
	
	boost::shared_ptr<Region> whole_file_region = get_parent();

	if (whole_file_region) {
		set_position (whole_file_region->position() + _start, src);
	}
}
	
void
Region::special_set_position (nframes_t pos)
{
	/* this is used when creating a whole file region as 
	   a way to store its "natural" or "captured" position.
	*/

	_position = _position;
	_position = pos;
}

void
Region::set_position_lock_style (PositionLockStyle ps)
{
	boost::shared_ptr<Playlist> pl (playlist());

	if (!pl) {
		return;
	}

	_positional_lock_style = ps;

	if (_positional_lock_style == MusicTime) {
		pl->session().tempo_map().bbt_time (_position, _bbt_time);
	}
	
}

void
Region::update_position_after_tempo_map_change ()
{
	boost::shared_ptr<Playlist> pl (playlist());
	
	if (!pl || _positional_lock_style != MusicTime) {
		return;
	}

	TempoMap& map (pl->session().tempo_map());
	nframes_t pos = map.frame_time (_bbt_time);
	set_position_internal (pos, false);
}

void
Region::set_position (nframes_t pos, void *src)
{
	if (_flags & Locked) {
		return;
	}

	set_position_internal (pos, true);
}

void
Region::set_position_internal (nframes_t pos, bool allow_bbt_recompute)
{
	if (_position != pos) {
		_last_position = _position;
		_position = pos;

		/* check that the new _position wouldn't make the current
		   length impossible - if so, change the length. 

		   XXX is this the right thing to do?
		*/

		if (max_frames - _length < _position) {
			_last_length = _length;
			_length = max_frames - _position;
		}

		if (allow_bbt_recompute) {
			recompute_position_from_lock_style ();
		}

		invalidate_transients ();
	}

	/* do this even if the position is the same. this helps out
	   a GUI that has moved its representation already.
	*/

	send_change (PositionChanged);
}

void
Region::set_position_on_top (nframes_t pos, void *src)
{
	if (_flags & Locked) {
		return;
	}

	if (_position != pos) {
		_last_position = _position;
		_position = pos;
	}

	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.
	*/
	
	send_change (PositionChanged);
}

void
Region::recompute_position_from_lock_style ()
{
	if (_positional_lock_style == MusicTime) {
		boost::shared_ptr<Playlist> pl (playlist());
		if (pl) {
			pl->session().tempo_map().bbt_time (_position, _bbt_time);
		}
	}
}
		
void
Region::nudge_position (nframes64_t n, void *src)
{
	if (_flags & Locked) {
		return;
	}

	if (n == 0) {
		return;
	}
	
	_last_position = _position;

	if (n > 0) {
		if (_position > max_frames - n) {
			_position = max_frames;
		} else {
			_position += n;
		}
	} else {
		if (_position < (nframes_t) -n) {
			_position = 0;
		} else {
			_position += n;
		}
	}

	send_change (PositionChanged);
}

void
Region::set_ancestral_data (nframes64_t s, nframes64_t l, float st, float sh)
{
	_ancestral_length = l;
	_ancestral_start = s;
	_stretch = st;
	_shift = sh;
}

void
Region::set_start (nframes_t pos, void *src)
{
	if (_flags & Locked) {
		return;
	}
	/* This just sets the start, nothing else. It effectively shifts
	   the contents of the Region within the overall extent of the Source,
	   without changing the Region's position or length
	*/

	if (_start != pos) {

		if (!verify_start (pos)) {
			return;
		}

		_start = pos;
		_flags = Region::Flag (_flags & ~WholeFile);
		first_edit ();
		invalidate_transients ();

		send_change (StartChanged);
	}
}

void
Region::trim_start (nframes_t new_position, void *src)
{
	if (_flags & Locked) {
		return;
	}
	nframes_t new_start;
	int32_t start_shift;
	
	if (new_position > _position) {
		start_shift = new_position - _position;
	} else {
		start_shift = -(_position - new_position);
	}

	if (start_shift > 0) {

		if (_start > max_frames - start_shift) {
			new_start = max_frames;
		} else {
			new_start = _start + start_shift;
		}

		if (!verify_start (new_start)) {
			return;
		}

	} else if (start_shift < 0) {

		if (_start < (nframes_t) -start_shift) {
			new_start = 0;
		} else {
			new_start = _start + start_shift;
		}
	} else {
		return;
	}

	if (new_start == _start) {
		return;
	}
	
	_start = new_start;
	_flags = Region::Flag (_flags & ~WholeFile);
	first_edit ();

	send_change (StartChanged);
}

void
Region::trim_front (nframes_t new_position, void *src)
{
	modify_front (new_position, false, src);
}

void
Region::cut_front (nframes_t new_position, void *src)
{
	modify_front (new_position, true, src);
}

void
Region::modify_front (nframes_t new_position, bool reset_fade, void *src)
{
	if (_flags & Locked) {
		return;
	}

	nframes_t end = last_frame();
	nframes_t source_zero;

	if (_position > _start) {
		source_zero = _position - _start;
	} else {
		source_zero = 0; // its actually negative, but this will work for us
	}

	if (new_position < end) { /* can't trim it zero or negative length */
		
		nframes_t newlen;

		/* can't trim it back passed where source position zero is located */
		
		new_position = max (new_position, source_zero);
		
		
		if (new_position > _position) {
			newlen = _length - (new_position - _position);
		} else {
			newlen = _length + (_position - new_position);
		}
		
		trim_to_internal (new_position, newlen, src);
		if (reset_fade) {
			_flags = Flag (_flags | RightOfSplit); /* force reset of fade in */
		}
		if (!_frozen) {
			recompute_at_start ();
		}
	}
}

void
Region::trim_end (nframes_t new_endpoint, void *src)
{
	modify_end (new_endpoint, false, src);
}

void
Region::cut_end (nframes_t new_endpoint, void *src)
{
	modify_end (new_endpoint, true, src);
}

void
Region::modify_end (nframes_t new_endpoint, bool reset_fade, void *src)
{
	if (_flags & Locked) {
		return;
	}

	if (new_endpoint > _position) {
		trim_to_internal (_position, new_endpoint - _position, this);
		if (reset_fade) {
			_flags = Flag (_flags | LeftOfSplit); /* force reset of fade out */
		}
		if (!_frozen) {
			recompute_at_end ();
		}
	}
}

void
Region::trim_to (nframes_t position, nframes_t length, void *src)
{
	if (_flags & Locked) {
		return;
	}

	trim_to_internal (position, length, src);

	if (!_frozen) {
		recompute_at_start ();
		recompute_at_end ();
	}
}

void
Region::trim_to_internal (nframes_t position, nframes_t length, void *src)
{
	int32_t start_shift;
	nframes_t new_start;

	if (_flags & Locked) {
		return;
	}

	if (position > _position) {
		start_shift = position - _position;
	} else {
		start_shift = -(_position - position);
	}

	if (start_shift > 0) {

		if (_start > max_frames - start_shift) {
			new_start = max_frames;
		} else {
			new_start = _start + start_shift;
		}


	} else if (start_shift < 0) {

		if (_start < (nframes_t) -start_shift) {
			new_start = 0;
		} else {
			new_start = _start + start_shift;
		}
	} else {
		new_start = _start;
	}

	if (!verify_start_and_length (new_start, length)) {
		return;
	}

	Change what_changed = Change (0);

	if (_start != new_start) {
		_start = new_start;
		what_changed = Change (what_changed|StartChanged);
	}
	if (_length != length) {
		if (!_frozen) {
			_last_length = _length;
		}
		_length = length;
		what_changed = Change (what_changed|LengthChanged);
	}
	if (_position != position) {
		if (!_frozen) {
			_last_position = _position;
		}
		_position = position;
		what_changed = Change (what_changed|PositionChanged);
	}
	
	_flags = Region::Flag (_flags & ~WholeFile);

	if (what_changed & (StartChanged|LengthChanged)) {
		first_edit ();
	} 

	if (what_changed) {
		send_change (what_changed);
	}
}	

void
Region::set_hidden (bool yn)
{
	if (hidden() != yn) {

		if (yn) {
			_flags = Flag (_flags|Hidden);
		} else {
			_flags = Flag (_flags & ~Hidden);
		}

		send_change (HiddenChanged);
	}
}

void
Region::set_muted (bool yn)
{
	if (muted() != yn) {

		if (yn) {
			_flags = Flag (_flags|Muted);
		} else {
			_flags = Flag (_flags & ~Muted);
		}

		send_change (MuteChanged);
	}
}

void
Region::set_opaque (bool yn)
{
	if (opaque() != yn) {
		if (yn) {
			_flags = Flag (_flags|Opaque);
		} else {
			_flags = Flag (_flags & ~Opaque);
		}
			send_change (OpacityChanged);
	}
}

void
Region::set_locked (bool yn)
{
	if (locked() != yn) {
		if (yn) {
			_flags = Flag (_flags|Locked);
		} else {
			_flags = Flag (_flags & ~Locked);
		}
		send_change (LockChanged);
	}
}

void
Region::set_sync_position (nframes_t absolute_pos)
{
	nframes_t const file_pos = _start + (absolute_pos - _position);

	if (file_pos != _sync_position) {
		
		_sync_position = file_pos;
		_flags = Flag (_flags|SyncMarked);

		if (!_frozen) {
			maybe_uncopy ();
		}
		send_change (SyncOffsetChanged);
	}
}

void
Region::clear_sync_position ()
{
	if (_flags & SyncMarked) {
		_flags = Flag (_flags & ~SyncMarked);

		if (!_frozen) {
			maybe_uncopy ();
		}
		send_change (SyncOffsetChanged);
	}
}

nframes_t
Region::sync_offset (int& dir) const
{
	/* returns the sync point relative the first frame of the region */

	if (_flags & SyncMarked) {
		if (_sync_position > _start) {
			dir = 1;
			return _sync_position - _start; 
		} else {
			dir = -1;
			return _start - _sync_position;
		}
	} else {
		dir = 0;
		return 0;
	}
}

nframes_t 
Region::adjust_to_sync (nframes_t pos) const
{
	int sync_dir;
	nframes_t offset = sync_offset (sync_dir);

	// cerr << "adjusting pos = " << pos << " to sync at " << _sync_position << " offset = " << offset << " with dir = " << sync_dir << endl;
	
	if (sync_dir > 0) {
		if (pos > offset) {
			pos -= offset;
		} else {
			pos = 0;
		}
	} else {
		if (max_frames - pos > offset) {
			pos += offset;
		}
	}

	return pos;
}

nframes_t
Region::sync_position() const
{
	if (_flags & SyncMarked) {
		return _sync_position; 
	} else {
		return _start;
	}
}


void
Region::raise ()
{
	boost::shared_ptr<Playlist> pl (playlist());
	if (pl) {
		pl->raise_region (shared_from_this ());
	}
}

void
Region::lower ()
{
	boost::shared_ptr<Playlist> pl (playlist());
	if (pl) {
		pl->lower_region (shared_from_this ());
	}
}

void
Region::raise_to_top ()
{
	boost::shared_ptr<Playlist> pl (playlist());
	if (pl) {
		pl->raise_region_to_top (shared_from_this());
	}
}

void
Region::lower_to_bottom ()
{
	boost::shared_ptr<Playlist> pl (playlist());
	if (pl) {
		pl->lower_region_to_bottom (shared_from_this());
	}
}

void
Region::set_layer (layer_t l)
{
	if (_layer != l) {
		_layer = l;
		
		send_change (LayerChanged);
	}
}

XMLNode&
Region::state (bool full_state)
{
	XMLNode *node = new XMLNode ("Region");
	char buf[64];
	const char* fe = NULL;

	_id.print (buf, sizeof (buf));
	node->add_property ("id", buf);
	node->add_property ("name", _name);
	snprintf (buf, sizeof (buf), "%u", _start);
	node->add_property ("start", buf);
	snprintf (buf, sizeof (buf), "%u", _length);
	node->add_property ("length", buf);
	snprintf (buf, sizeof (buf), "%u", _position);
	node->add_property ("position", buf);
	snprintf (buf, sizeof (buf), "%" PRIi64, _ancestral_start);
	node->add_property ("ancestral-start", buf);
	snprintf (buf, sizeof (buf), "%" PRIi64, _ancestral_length);
	node->add_property ("ancestral-length", buf);
	snprintf (buf, sizeof (buf), "%.12g", _stretch);
	node->add_property ("stretch", buf);
	snprintf (buf, sizeof (buf), "%.12g", _shift);
	node->add_property ("shift", buf);
	
	switch (_first_edit) {
	case EditChangesNothing:
		fe = X_("nothing");
		break;
	case EditChangesName:
		fe = X_("name");
		break;
	case EditChangesID:
		fe = X_("id");
		break;
	default: /* should be unreachable but makes g++ happy */
		fe = X_("nothing");
		break;
	}

	node->add_property ("first_edit", fe);

	/* note: flags are stored by derived classes */

	snprintf (buf, sizeof (buf), "%d", (int) _layer);
	node->add_property ("layer", buf);
	snprintf (buf, sizeof (buf), "%" PRIu32, _sync_position);
	node->add_property ("sync-position", buf);

	if (_positional_lock_style != AudioTime) {
		node->add_property ("positional-lock-style", enum_2_string (_positional_lock_style));
		stringstream str;
		str << _bbt_time;
		node->add_property ("bbt-position", str.str());
	}

	return *node;
}

XMLNode&
Region::get_state ()
{
	return state (true);
}

int
Region::set_live_state (const XMLNode& node, Change& what_changed, bool send)
{
	const XMLNodeList& nlist = node.children();
	const XMLProperty *prop;
	nframes_t val;

	/* this is responsible for setting those aspects of Region state 
	   that are mutable after construction.
	*/

	if ((prop = node.property ("name")) == 0) {
		error << _("XMLNode describing a Region is incomplete (no name)") << endmsg;
		return -1;
	}

	_name = prop->value();

	if ((prop = node.property ("start")) != 0) {
		sscanf (prop->value().c_str(), "%" PRIu32, &val);
		if (val != _start) {
			what_changed = Change (what_changed|StartChanged);	
			_start = val;
		}
	} else {
		_start = 0;
	}

	if ((prop = node.property ("length")) != 0) {
		sscanf (prop->value().c_str(), "%" PRIu32, &val);
		if (val != _length) {
			what_changed = Change (what_changed|LengthChanged);
			_last_length = _length;
			_length = val;
		}
	} else {
		_last_length = _length;
		_length = 1;
	}

	if ((prop = node.property ("position")) != 0) {
		sscanf (prop->value().c_str(), "%" PRIu32, &val);
		if (val != _position) {
			what_changed = Change (what_changed|PositionChanged);
			_last_position = _position;
			_position = val;
		}
	} else {
		_last_position = _position;
		_position = 0;
	}

	if ((prop = node.property ("layer")) != 0) {
		layer_t x;
		x = (layer_t) atoi (prop->value().c_str());
		if (x != _layer) {
			what_changed = Change (what_changed|LayerChanged);
			_layer = x;
		}
	} else {
		_layer = 0;
	}

	if ((prop = node.property ("sync-position")) != 0) {
		sscanf (prop->value().c_str(), "%" PRIu32, &val);
		if (val != _sync_position) {
			what_changed = Change (what_changed|SyncOffsetChanged);
			_sync_position = val;
		}
	} else {
		_sync_position = _start;
	}

	if ((prop = node.property ("positional-lock-style")) != 0) {
		_positional_lock_style = PositionLockStyle (string_2_enum (prop->value(), _positional_lock_style));

		if (_positional_lock_style == MusicTime) {
			if ((prop = node.property ("bbt-position")) == 0) {
				/* missing BBT info, revert to audio time locking */
				_positional_lock_style = AudioTime;
			} else {
				if (sscanf (prop->value().c_str(), "%d|%d|%d", 
					    &_bbt_time.bars,
					    &_bbt_time.beats,
					    &_bbt_time.ticks) != 3) {
					_positional_lock_style = AudioTime;
				}
			}
		}
			
	} else {
		_positional_lock_style = AudioTime;
	}

	/* XXX FIRST EDIT !!! */
	
	/* these 3 properties never change as a result of any editing */

	if ((prop = node.property ("ancestral-start")) != 0) {
		_ancestral_start = atoi (prop->value());
	} else {
		_ancestral_start = _start;
	}

	if ((prop = node.property ("ancestral-length")) != 0) {
		_ancestral_length = atoi (prop->value());
	} else {
		_ancestral_length = _length;
	}

	if ((prop = node.property ("stretch")) != 0) {
		_stretch = atof (prop->value());
		/* fix problem with old sessions corrupted by an impossible
		   value for _stretch
		*/
		if (_stretch == 0.0) {
			_stretch = 1.0;
		}
	} else {
		_stretch = 1.0;
	}

	if ((prop = node.property ("shift")) != 0) {
		_shift = atof (prop->value());
		/* fix problem with old sessions corrupted by an impossible
		   value for _shift
		*/
		if (_shift == 0.0) {
			_shift = 1.0;
		}
	} else {
		_shift = 1.0;
	}

	/* note: derived classes set flags */

	if (_extra_xml) {
		delete _extra_xml;
		_extra_xml = 0;
	}

	for (XMLNodeConstIterator niter = nlist.begin(); niter != nlist.end(); ++niter) {
		
		XMLNode *child;
		
		child = (*niter);
		
		if (child->name () == "extra") {
			_extra_xml = new XMLNode (*child);
			break;
		}
	}

	if (send) {
		send_change (what_changed);
	}

	return 0;
}

int
Region::set_state (const XMLNode& node)
{
	const XMLProperty *prop;
	Change what_changed = Change (0);

	/* ID is not allowed to change, ever */

	if ((prop = node.property ("id")) == 0) {
		error << _("Session: XMLNode describing a Region is incomplete (no id)") << endmsg;
		return -1;
	}

	_id = prop->value();
	
	_first_edit = EditChangesNothing;
	
	set_live_state (node, what_changed, true);

	return 0;
}

void
Region::freeze ()
{
	_frozen++;
	_last_length = _length;
	_last_position = _position;
}

void
Region::thaw (const string& why)
{
	Change what_changed = Change (0);

	{
		Glib::Mutex::Lock lm (lock);

		if (_frozen && --_frozen > 0) {
			return;
		}

		if (pending_changed) {
			what_changed = pending_changed;
			pending_changed = Change (0);
		}
	}

	if (what_changed == Change (0)) {
		return;
	}

	if (what_changed & LengthChanged) {
		if (what_changed & PositionChanged) {
			recompute_at_start ();
		} 
		recompute_at_end ();
	}
		
	StateChanged (what_changed);
}

void
Region::send_change (Change what_changed)
{
	{
		Glib::Mutex::Lock lm (lock);
		if (_frozen) {
			pending_changed = Change (pending_changed|what_changed);
			return;
		} 
	}

	StateChanged (what_changed);
}

void
Region::set_last_layer_op (uint64_t when)
{
	_last_layer_op = when;
}

bool
Region::overlap_equivalent (boost::shared_ptr<const Region> other) const
{
	return coverage (other->first_frame(), other->last_frame()) != OverlapNone;
}

bool
Region::equivalent (boost::shared_ptr<const Region> other) const
{
	return _start == other->_start &&
		_position == other->_position &&
		_length == other->_length;
}

bool
Region::size_equivalent (boost::shared_ptr<const Region> other) const
{
	return _start == other->_start &&
		_length == other->_length;
}

bool
Region::region_list_equivalent (boost::shared_ptr<const Region> other) const
{
	return size_equivalent (other) && source_equivalent (other) && _name == other->_name;
}

void
Region::invalidate_transients ()
{
	valid_transients = false;
	_transients.clear ();
}