summaryrefslogtreecommitdiff
path: root/libs/ardour/ardour/session.h
blob: 9ab716ebc97af57d8ba8623ac6068aa27e3230fc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
/*
 * Copyright (C) 2000-2019 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2005-2009 Taybin Rutkin <taybin@taybin.com>
 * Copyright (C) 2006-2007 Jesse Chappell <jesse@essej.net>
 * Copyright (C) 2006-2009 Sampo Savolainen <v2@iki.fi>
 * Copyright (C) 2006-2015 David Robillard <d@drobilla.net>
 * Copyright (C) 2007-2012 Carl Hetherington <carl@carlh.net>
 * Copyright (C) 2007-2015 Tim Mayberry <mojofunk@gmail.com>
 * Copyright (C) 2008-2009 Hans Baier <hansfbaier@googlemail.com>
 * Copyright (C) 2008-2009 Sakari Bergen <sakari.bergen@beatwaves.net>
 * Copyright (C) 2012-2019 Robin Gareus <robin@gareus.org>
 * Copyright (C) 2013-2017 Nick Mainsbridge <mainsbridge@gmail.com>
 * Copyright (C) 2013-2018 John Emmas <john@creativepost.co.uk>
 * Copyright (C) 2014-2018 Ben Loftis <ben@harrisonconsoles.com>
 * Copyright (C) 2015-2018 Len Ovens <len@ovenwerks.net>
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef __ardour_session_h__
#define __ardour_session_h__

#ifdef WAF_BUILD
#include "libardour-config.h"
#endif

#include <exception>
#include <list>
#include <map>
#include <set>
#include <string>
#include <vector>
#include <queue>
#include <stdint.h>

#include <boost/dynamic_bitset.hpp>
#include <boost/scoped_ptr.hpp>
#include <boost/weak_ptr.hpp>
#include <boost/utility.hpp>

#include <glibmm/threads.h>

#include <ltc.h>

#include "pbd/error.h"
#include "pbd/event_loop.h"
#include "pbd/file_archive.h"
#include "pbd/rcu.h"
#include "pbd/reallocpool.h"
#include "pbd/statefuldestructible.h"
#include "pbd/signals.h"
#include "pbd/undo.h"

#include "lua/luastate.h"

#include "evoral/Range.h"

#include "midi++/types.h"
#include "midi++/mmc.h"

#include "temporal/time.h"

#include "ardour/ardour.h"
#include "ardour/chan_count.h"
#include "ardour/delivery.h"
#include "ardour/interthread_info.h"
#include "ardour/luascripting.h"
#include "ardour/location.h"
#include "ardour/monitor_processor.h"
#include "ardour/presentation_info.h"
#include "ardour/rc_configuration.h"
#include "ardour/session_configuration.h"
#include "ardour/session_event.h"
#include "ardour/interpolation.h"
#include "ardour/plugin.h"
#include "ardour/presentation_info.h"
#include "ardour/route.h"
#include "ardour/route_graph.h"
#include "ardour/transport_api.h"

class XMLTree;
class XMLNode;
struct _AEffect;
typedef struct _AEffect AEffect;

class PTFFormat;

namespace MIDI {
class Port;
class MachineControl;
class Parser;
}

namespace PBD {
class Controllable;
}

namespace luabridge {
	class LuaRef;
}

namespace Evoral {
class Curve;
}

namespace ARDOUR {

class Amp;
class AsyncMIDIPort;
class AudioEngine;
class AudioFileSource;
class AudioRegion;
class AudioSource;
class AudioTrack;
class Auditioner;
class AutomationList;
class AuxInput;
class BufferSet;
class Bundle;
class Butler;
class Click;
class CoreSelection;
class ExportHandler;
class ExportStatus;
class Graph;
class IO;
class IOProcessor;
class ImportStatus;
class MidiClockTicker;
class MidiControlUI;
class MidiPortManager;
class MidiPort;
class MidiRegion;
class MidiSource;
class MidiTrack;
class Playlist;
class PluginInsert;
class PluginInfo;
class Port;
class PortInsert;
class ProcessThread;
class Progress;
class Processor;
class Region;
class Return;
class Route;
class RouteGroup;
class RTTaskList;
class SMFSource;
class Send;
class SceneChanger;
class SessionDirectory;
class SessionMetadata;
class SessionPlaylists;
class Source;
class Speakers;
class TempoMap;
class TransportMaster;
struct TransportFSM;
class Track;
class UI_TransportMaster;
class VCAManager;
class WindowsVSTPlugin;

extern void setup_enum_writer ();

class LIBARDOUR_API SessionException: public std::exception {
public:
	explicit SessionException(const std::string msg) : _message(msg) {}
	virtual ~SessionException() throw() {}

	virtual const char* what() const throw() { return _message.c_str(); }

private:
	std::string _message;
};

/** Ardour Session */
class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::ScopedConnectionList, public SessionEventManager, public TransportAPI
{
private:

public:
	enum RecordState {
		Disabled = 0,
		Enabled = 1,
		Recording = 2
	};

	/* a new session might have non-empty mix_template, an existing session should always have an empty one.
	   the bus profile can be null if no master out bus is required.
	*/

	Session (AudioEngine&,
	         const std::string& fullpath,
	         const std::string& snapshot_name,
	         BusProfile const * bus_profile = 0,
	         std::string mix_template = "",
	         bool unnamed = false);

	virtual ~Session ();

	static int get_info_from_path (const std::string& xmlpath, float& sample_rate, SampleFormat& data_format, std::string& program_version);
	static std::string get_snapshot_from_instant (const std::string& session_dir);

	/** a monotonic counter used for naming user-visible things uniquely
	 * (curently the sidechain port).
	 * Use sparingly to keep the numbers low, prefer PBD::ID for all
	 * internal, not user-visible IDs */
	static unsigned int next_name_id ();

	std::string path() const { return _path; }
	std::string name() const { return _name; }
	std::string snap_name() const { return _current_snapshot_name; }
	std::string raid_path () const;
	bool path_is_within_session (const std::string&);

	bool writable() const { return _writable; }
	void set_clean ();   // == Clean and emit DirtyChanged IFF session was Dirty
	void set_dirty ();   // |= Dirty and emit DirtyChanged (unless already dirty or Loading, Deletion)
	void unset_dirty (bool emit_dirty_changed = false); // &= ~Dirty
	void set_deletion_in_progress ();   // |= Deletion
	void clear_deletion_in_progress (); // &= ~Deletion

	bool reconnection_in_progress () const         { return _reconnecting_routes_in_progress; }
	bool routes_deletion_in_progress () const      { return _route_deletion_in_progress; }
	bool dirty () const                            { return _state_of_the_state & Dirty; }
	bool deletion_in_progress () const             { return _state_of_the_state & Deletion; }
	bool peaks_cleanup_in_progres () const         { return _state_of_the_state & PeakCleanup; }
	bool loading () const                          { return _state_of_the_state & Loading; }
	bool cannot_save () const                      { return _state_of_the_state & CannotSave; }
	bool in_cleanup () const                       { return _state_of_the_state & InCleanup; }
	bool inital_connect_or_deletion_in_progress () const { return _state_of_the_state & (InitialConnecting | Deletion); }
	bool unnamed() const;

	void end_unnamed_status () const;

	PBD::Signal0<void> DirtyChanged;

	const SessionDirectory& session_directory () const { return *(_session_dir.get()); }

	static PBD::Signal1<void,std::string> Dialog;

	PBD::Signal0<void> BatchUpdateStart;
	PBD::Signal0<void> BatchUpdateEnd;

	int ensure_subdirs ();

	std::string automation_dir () const;  ///< Automation data
	std::string analysis_dir () const;    ///< Analysis data
	std::string plugins_dir () const;     ///< Plugin state
	std::string externals_dir () const;   ///< Links to external files

	std::string construct_peak_filepath (const std::string& audio_path, const bool in_session = false, const bool old_peak_name = false) const;

	bool audio_source_name_is_unique (const std::string& name);
	std::string format_audio_source_name (const std::string& legalized_base, uint32_t nchan, uint32_t chan, bool take_required, uint32_t cnt, bool related_exists);
	std::string new_audio_source_path_for_embedded (const std::string& existing_path);
	std::string new_audio_source_path (const std::string&, uint32_t nchans, uint32_t chan, bool take_required);
	std::string new_midi_source_path (const std::string&, bool need_source_lock = true);

	/** create a new track or bus from a template (XML path)
	 * @param how_many how many tracks or busses to create
	 * @param template_path path to xml template file
	 * @param insert_at position where to add new track, use PresentationInfo::max_order to append at the end.
	 * @param name name (prefix) of the route to create
	 * @param pd Playlist disposition
	 * @return list of newly created routes
	 */
	RouteList new_route_from_template (uint32_t how_many, PresentationInfo::order_t insert_at, const std::string& template_path, const std::string& name, PlaylistDisposition pd = NewPlaylist);
	RouteList new_route_from_template (uint32_t how_many, PresentationInfo::order_t insert_at, XMLNode&, const std::string& name, PlaylistDisposition pd = NewPlaylist);
	std::vector<std::string> get_paths_for_new_sources (bool allow_replacing, const std::string& import_file_path,
	                                                    uint32_t channels, std::vector<std::string> const & smf_track_names);

	int bring_all_sources_into_session (boost::function<void(uint32_t,uint32_t,std::string)> callback);

	void process (pframes_t nframes);

	void send_ltc_for_cycle (samplepos_t, samplepos_t, pframes_t);

	BufferSet& get_silent_buffers (ChanCount count = ChanCount::ZERO);
	BufferSet& get_noinplace_buffers (ChanCount count = ChanCount::ZERO);
	BufferSet& get_scratch_buffers (ChanCount count = ChanCount::ZERO, bool silence = true);
	BufferSet& get_route_buffers (ChanCount count = ChanCount::ZERO, bool silence = true);
	BufferSet& get_mix_buffers (ChanCount count = ChanCount::ZERO);

	bool have_rec_enabled_track () const;
	bool have_rec_disabled_track () const;

	bool have_captured() const { return _have_captured; }

	void refill_all_track_buffers ();
	Butler* butler() { return _butler; }
	void butler_transport_work ();

	void refresh_disk_space ();

	int load_routes (const XMLNode&, int);
	boost::shared_ptr<RouteList> get_routes() const {
		return routes.reader ();
	}

	boost::shared_ptr<RTTaskList> rt_tasklist () { return _rt_tasklist; }

	RouteList get_routelist (bool mixer_order = false, PresentationInfo::Flag fl = PresentationInfo::MixerRoutes) const;

	CoreSelection& selection () { return *_selection; }

	/* because the set of Stripables consists of objects managed
	 * independently, in multiple containers within the Session (or objects
	 * owned by the session), we fill out a list in-place rather than
	 * return a pointer to a copy of the (RCU) managed list, as happens
	 * with get_routes()
	 */

	void get_stripables (StripableList&, PresentationInfo::Flag fl = PresentationInfo::MixerStripables) const;
	StripableList get_stripables () const;
	boost::shared_ptr<RouteList> get_tracks() const;
	boost::shared_ptr<RouteList> get_routes_with_internal_returns() const;
	boost::shared_ptr<RouteList> get_routes_with_regions_at (samplepos_t const) const;

	boost::shared_ptr<AudioTrack> get_nth_audio_track (int nth) const;

	uint32_t nstripables (bool with_monitor = false) const;
	uint32_t nroutes() const { return routes.reader()->size(); }
	uint32_t ntracks () const;
	uint32_t nbusses () const;

	bool plot_process_graph (std::string const& file_name) const;

	boost::shared_ptr<BundleList> bundles () {
		return _bundles.reader ();
	}

	void notify_presentation_info_change ();

	template<class T> void foreach_route (T *obj, void (T::*func)(Route&), bool sort = true);
	template<class T> void foreach_route (T *obj, void (T::*func)(boost::shared_ptr<Route>), bool sort = true);
	template<class T, class A> void foreach_route (T *obj, void (T::*func)(Route&, A), A arg, bool sort = true);

	static char session_name_is_legal (const std::string&);
	bool io_name_is_legal (const std::string&) const;
	boost::shared_ptr<Route> route_by_name (std::string) const;
	boost::shared_ptr<Route> route_by_id (PBD::ID) const;
	boost::shared_ptr<Stripable> stripable_by_id (PBD::ID) const;
	boost::shared_ptr<Stripable> get_remote_nth_stripable (PresentationInfo::order_t n, PresentationInfo::Flag) const;
	boost::shared_ptr<Route> get_remote_nth_route (PresentationInfo::order_t n) const;
	boost::shared_ptr<Route> route_by_selected_count (uint32_t cnt) const;
	void routes_using_input_from (const std::string& str, RouteList& rl);

	bool route_name_unique (std::string) const;
	bool route_name_internal (std::string) const;

	uint32_t track_number_decimals () const {
		return _track_number_decimals;
	}

	bool get_record_enabled() const {
		return (record_status () >= Enabled);
	}

	RecordState record_status() const {
		return (RecordState) g_atomic_int_get (&_record_status);
	}

	bool actively_recording () const {
		return record_status() == Recording;
	}

	bool record_enabling_legal () const;
	void maybe_enable_record (bool rt_context = false);
	void disable_record (bool rt_context, bool force = false);
	void step_back_from_record ();

	void set_all_tracks_record_enabled(bool);

	void maybe_write_autosave ();

	/* Emitted when all i/o connections are complete */

	PBD::Signal0<void> IOConnectionsComplete;

	/* Record status signals */

	PBD::Signal0<void> RecordStateChanged; /* signals changes in recording state (i.e. are we recording) */
	/* XXX may 2015: paul says: it isn't clear to me that this has semantics that cannot be inferrred
	   from the previous signal and session state.
	*/
	PBD::Signal0<void> RecordArmStateChanged; /* signals changes in recording arming */

	/* Emited when session is loaded */
	PBD::Signal0<void> SessionLoaded;

	/* Transport mechanism signals */

	/** Emitted on the following changes in transport state:
	 *  - stop (from the butler thread)
	 *  - change in whether or not we are looping (from the process thread)
	 *  - change in the play range (from the process thread)
	 *  - start (from the process thread)
	 *  - engine halted
	 */
	PBD::Signal0<void> TransportStateChange;

	PBD::Signal1<void,samplepos_t> PositionChanged; /* sent after any non-sequential motion */
	PBD::Signal1<void,samplepos_t> Xrun;
	PBD::Signal0<void> TransportLooped;

	/** emitted when a locate has occurred */
	PBD::Signal0<void> Located;

	PBD::Signal1<void,RouteList&> RouteAdded;
	/** Emitted when a property of one of our route groups changes.
	 *  The parameter is the RouteGroup that has changed.
	 */
	PBD::Signal1<void, RouteGroup *> RouteGroupPropertyChanged;
	/** Emitted when a route is added to one of our route groups.
	 *  First parameter is the RouteGroup, second is the route.
	 */
	PBD::Signal2<void, RouteGroup *, boost::weak_ptr<Route> > RouteAddedToRouteGroup;
	/** Emitted when a route is removed from one of our route groups.
	 *  First parameter is the RouteGroup, second is the route.
	 */
	PBD::Signal2<void, RouteGroup *, boost::weak_ptr<Route> > RouteRemovedFromRouteGroup;

	/** Emitted when a foldback send is created or deleted
	 */
	PBD::Signal0<void> FBSendsChanged;

	/* Step Editing status changed */
	PBD::Signal1<void,bool> StepEditStatusChange;

	/* Timecode state signals */
	PBD::Signal0<void> MtcOrLtcInputPortChanged;

	void queue_event (SessionEvent*);

	void request_roll_at_and_return (samplepos_t start, samplepos_t return_to);
	void request_bounded_roll (samplepos_t start, samplepos_t end);
	void request_stop (bool abort = false, bool clear_state = false, TransportRequestSource origin = TRS_UI);
	void request_locate (samplepos_t sample, LocateTransportDisposition ltd = RollIfAppropriate, TransportRequestSource origin = TRS_UI);

	void request_play_loop (bool yn, bool leave_rolling = false);
	bool get_play_loop () const { return play_loop; }

	samplepos_t last_transport_start () const { return _last_roll_location; }
	void goto_end ();
	void goto_start (bool and_roll = false);
	void use_rf_shuttle_speed ();
	void allow_auto_play (bool yn);
	void request_transport_speed (double speed, bool as_default = true, TransportRequestSource origin = TRS_UI);
	void request_transport_speed_nonzero (double, bool as_default = true, TransportRequestSource origin = TRS_UI);
	void request_overwrite_buffer (boost::shared_ptr<Track>, OverwriteReason);
	void adjust_playback_buffering();
	void adjust_capture_buffering();

	bool global_locate_pending() const { return _global_locate_pending; }
	bool locate_pending() const;
	bool locate_initiated() const;
	bool declick_in_progress () const;
	bool transport_locked () const;

	bool had_destructive_tracks () const;
	void set_had_destructive_tracks (bool yn);

	int wipe ();

	samplepos_t current_end_sample () const;
	samplepos_t current_start_sample () const;
	/** "actual" sample rate of session, set by current audioengine rate, pullup/down etc. */
	samplecnt_t sample_rate () const { return _current_sample_rate; }
	/** "native" sample rate of session, regardless of current audioengine rate, pullup/down etc */
	samplecnt_t nominal_sample_rate () const { return _nominal_sample_rate; }
	samplecnt_t frames_per_hour () const { return _frames_per_hour; }

	double samples_per_timecode_frame() const { return _samples_per_timecode_frame; }
	samplecnt_t timecode_frames_per_hour() const { return _timecode_frames_per_hour; }

	MIDI::byte get_mtc_timecode_bits() const {
		return mtc_timecode_bits;   /* encoding of SMTPE type for MTC */
	}

	double timecode_frames_per_second() const;
	bool timecode_drop_frames() const;

	/* Locations */

	Locations *locations() { return _locations; }

	PBD::Signal1<void,Location*>    auto_loop_location_changed;
	PBD::Signal1<void,Location*>    auto_punch_location_changed;
	PBD::Signal0<void>              locations_modified;

	void set_auto_punch_location (Location *);
	void set_auto_loop_location (Location *);
	void set_session_extents (samplepos_t start, samplepos_t end);
	bool session_range_is_free () const { return _session_range_is_free; }
	void set_session_range_is_free (bool);

	pframes_t get_block_size () const         { return current_block_size; }
	samplecnt_t worst_output_latency () const { return _worst_output_latency; }
	samplecnt_t worst_input_latency () const  { return _worst_input_latency; }
	samplecnt_t worst_route_latency () const  { return _worst_route_latency; }
	samplecnt_t worst_latency_preroll () const;
	samplecnt_t worst_latency_preroll_buffer_size_ceil () const;

	PBD::Signal1<void, bool> LatencyUpdated;

	struct SaveAs {
		std::string new_parent_folder;  /* parent folder where new session folder will be created */
		std::string new_name;           /* name of newly saved session */
		bool        switch_to;     /* true if we should be working on newly saved session after save-as; false otherwise */
		bool        include_media; /* true if the newly saved session should contain references to media */
		bool        copy_media;    /* true if media files (audio, media, etc) should be copied into newly saved session; false otherwise */
		bool        copy_external; /* true if external media should be consolidated into the newly saved session; false otherwise */

		std::string final_session_folder_name; /* filled in by * Session::save_as(), provides full path to newly saved session */

		/* emitted as we make progress. 3 arguments passed to signal
		 * handler:
		 *
		 *  1: percentage complete measured as a fraction (0-1.0) of
		 *     total data copying done.
		 *  2: number of files copied so far
		 *  3: total number of files to copy
		 *
		 * Handler should return true for save-as to continue, or false
		 * to stop (and remove all evidence of partial save-as).
		 */
		PBD::Signal3<bool,float,int64_t,int64_t> Progress;

		/* if save_as() returns non-zero, this string will indicate the reason why.
		 */
		std::string failure_message;
	};

	int save_as (SaveAs&);

	/** save session
	 * @param snapshot_name name of the session (use an empty string for the current name)
	 * @param pending save a 'recovery', not full state (default: false)
	 * @param switch_to_snapshot switch to given snapshot after saving (default: false)
	 * @param template_only save a session template (default: false)
	 * @param for_archive save only data relevant for session-archive
	 * @param only_used_assets skip Sources that are not used, mainly useful with \p for_archive
	 * @return zero on success
	 */
	int save_state (std::string snapshot_name,
	                bool pending = false,
	                bool switch_to_snapshot = false,
	                bool template_only = false,
	                bool for_archive = false,
	                bool only_used_assets = false);

	enum ArchiveEncode {
		NO_ENCODE,
		FLAC_16BIT,
		FLAC_24BIT
	};

	int archive_session (const std::string&, const std::string&,
	                     ArchiveEncode compress_audio = FLAC_16BIT,
	                     PBD::FileArchive::CompressionLevel compression_level = PBD::FileArchive::CompressGood,
	                     bool only_used_sources = false,
	                     Progress* p = 0);

	int restore_state (std::string snapshot_name);
	int save_template (const std::string& template_name, const std::string& description = "", bool replace_existing = false);
	int save_history (std::string snapshot_name = "");
	int restore_history (std::string snapshot_name);
	void remove_state (std::string snapshot_name);
	void rename_state (std::string old_name, std::string new_name);
	void remove_pending_capture_state ();
	int rename (const std::string&);
	bool get_nsm_state () const { return _under_nsm_control; }
	void set_nsm_state (bool state) { _under_nsm_control = state; }
	bool save_default_options ();

	PBD::Signal1<void,std::string> StateSaved;
	PBD::Signal0<void> StateReady;

	/* emitted when session needs to be saved due to some internal
	 * event or condition (i.e. not in response to a user request).
	 *
	 * Only one object should
	 * connect to this signal and take responsibility.
	 *
	 * Argument is the snapshot name to use when saving.
	 */
	PBD::Signal1<void,std::string> SaveSessionRequested;

	/* emitted during a session save to allow other entities to add state, via
	 * extra XML, to the session state
	 */
	PBD::Signal0<void> SessionSaveUnderway;

	std::vector<std::string> possible_states() const;
	static std::vector<std::string> possible_states (std::string path);

	bool export_track_state (boost::shared_ptr<RouteList> rl, const std::string& path);

	/// The instant xml file is written to the session directory
	void add_instant_xml (XMLNode&, bool write_to_config = true);
	XMLNode* instant_xml (const std::string& str);

	enum StateOfTheState {
		Clean = 0x0,
		Dirty = 0x1,
		CannotSave = 0x2,
		Deletion = 0x4,
		InitialConnecting = 0x8,
		Loading = 0x10,
		InCleanup = 0x20,
		PeakCleanup = 0x40
	};

	class StateProtector {
		public:
			StateProtector (Session* s) : _session (s) {
				g_atomic_int_inc (&s->_suspend_save);
			}
			~StateProtector () {
				if (g_atomic_int_dec_and_test (&_session->_suspend_save)) {
					while (_session->_save_queued) {
						_session->_save_queued = false;
						_session->save_state ("");
					}
					while (_session->_save_queued_pending) {
						_session->_save_queued_pending = false;
						_session->save_state ("", true);
					}
				}
			}
		private:
			Session * _session;
	};

	class ProcessorChangeBlocker {
	public:
		ProcessorChangeBlocker (Session* s, bool rc = true)
			: _session (s)
			, _reconfigure_on_delete (rc)
		{
			g_atomic_int_inc (&s->_ignore_route_processor_changes);
		}

		~ProcessorChangeBlocker ()
		{
			if (g_atomic_int_dec_and_test (&_session->_ignore_route_processor_changes)) {
				if (g_atomic_int_compare_and_exchange (&_session->_ignored_a_processor_change, 1, 0)) {
					if (_reconfigure_on_delete) {
						_session->route_processors_changed (RouteProcessorChange ());
					}
				}
			}
		}
	private:
		Session* _session;
		bool _reconfigure_on_delete;
	};

	RouteGroup* new_route_group (const std::string&);
	void add_route_group (RouteGroup *);
	void remove_route_group (RouteGroup* rg) { if (rg) remove_route_group (*rg); }
	void remove_route_group (RouteGroup&);
	void reorder_route_groups (std::list<RouteGroup*>);

	RouteGroup* route_group_by_name (std::string);
	RouteGroup& all_route_group() const;

	PBD::Signal1<void,RouteGroup*> route_group_added;
	PBD::Signal0<void>             route_group_removed;
	PBD::Signal0<void>             route_groups_reordered;

	void foreach_route_group (boost::function<void(RouteGroup*)> f) {
		for (std::list<RouteGroup *>::iterator i = _route_groups.begin(); i != _route_groups.end(); ++i) {
			f (*i);
		}
	}

	std::list<RouteGroup*> const & route_groups () const {
		return _route_groups;
	}

	/* fundamental operations. duh. */

	std::list<boost::shared_ptr<AudioTrack> > new_audio_track (
		int input_channels,
		int output_channels,
		RouteGroup* route_group,
		uint32_t how_many,
		std::string name_template,
		PresentationInfo::order_t order,
		TrackMode mode = Normal,
		bool input_auto_connect = true
		);

	std::list<boost::shared_ptr<MidiTrack> > new_midi_track (
		const ChanCount& input, const ChanCount& output, bool strict_io,
		boost::shared_ptr<PluginInfo> instrument,
		Plugin::PresetRecord* pset,
		RouteGroup* route_group, uint32_t how_many, std::string name_template,
		PresentationInfo::order_t,
		TrackMode mode = Normal
		);

	RouteList new_audio_route (int input_channels, int output_channels, RouteGroup* route_group, uint32_t how_many, std::string name_template, PresentationInfo::Flag, PresentationInfo::order_t);
	RouteList new_midi_route (RouteGroup* route_group, uint32_t how_many, std::string name_template, bool strict_io, boost::shared_ptr<PluginInfo> instrument, Plugin::PresetRecord*, PresentationInfo::Flag, PresentationInfo::order_t);

	void remove_routes (boost::shared_ptr<RouteList>);
	void remove_route (boost::shared_ptr<Route>);

	void resort_routes ();
	void resort_routes_using (boost::shared_ptr<RouteList>);

	AudioEngine & engine() { return _engine; }
	AudioEngine const & engine () const { return _engine; }

	static std::string default_track_name_pattern (DataType);

	/* Time */

	samplepos_t transport_sample () const { return _transport_sample; }
	samplepos_t record_location () const { return _last_record_location; }
	samplepos_t audible_sample (bool* latent_locate = NULL) const;
	samplepos_t requested_return_sample() const { return _requested_return_sample; }
	void set_requested_return_sample(samplepos_t return_to);
	boost::optional<samplepos_t> const & nominal_jack_transport_sample() { return _nominal_jack_transport_sample; }

	bool compute_audible_delta (samplepos_t& pos_and_delta) const;
	samplecnt_t remaining_latency_preroll () const { return _remaining_latency_preroll; }

	enum PullupFormat {
		pullup_Plus4Plus1,
		pullup_Plus4,
		pullup_Plus4Minus1,
		pullup_Plus1,
		pullup_None,
		pullup_Minus1,
		pullup_Minus4Plus1,
		pullup_Minus4,
		pullup_Minus4Minus1
	};

	void sync_time_vars();

	void bbt_time (samplepos_t when, Timecode::BBT_Time&);
	void timecode_to_sample(Timecode::Time& timecode, samplepos_t& sample, bool use_offset, bool use_subframes) const;
	void sample_to_timecode(samplepos_t sample, Timecode::Time& timecode, bool use_offset, bool use_subframes) const;
	void timecode_time (Timecode::Time &);
	void timecode_time (samplepos_t when, Timecode::Time&);
	void timecode_time_subframes (samplepos_t when, Timecode::Time&);

	void timecode_duration (samplecnt_t, Timecode::Time&) const;
	void timecode_duration_string (char *, size_t len, samplecnt_t) const;

	samplecnt_t convert_to_samples (AnyTime const & position);
	samplecnt_t any_duration_to_samples (samplepos_t position, AnyTime const & duration);

	static PBD::Signal1<void, samplepos_t> StartTimeChanged;
	static PBD::Signal1<void, samplepos_t> EndTimeChanged;

	void   request_sync_source (boost::shared_ptr<TransportMaster>);
	bool   synced_to_engine() const;

	double engine_speed() const { return _engine_speed; }
	double actual_speed() const {
		if (_transport_speed > 0) return _engine_speed;
		if (_transport_speed < 0) return - _engine_speed;
		return 0;
	}
	double transport_speed() const { return _count_in_samples > 0 ? 0. : _transport_speed; }
	bool   transport_stopped() const;
	bool   transport_stopped_or_stopping() const;
	bool   transport_rolling() const;
	bool   transport_will_roll_forwards() const;

	bool silent () { return _silent; }

	bool punch_is_possible () const;
	bool loop_is_possible () const;
	PBD::Signal0<void> PunchLoopConstraintChange;

	TempoMap&       tempo_map()       { return *_tempo_map; }
	const TempoMap& tempo_map() const { return *_tempo_map; }
	void maybe_update_tempo_from_midiclock_tempo (float bpm);

	unsigned int    get_xrun_count () const {return _xrun_count; }
	void            reset_xrun_count () {_xrun_count = 0; }

	/* region info  */

	boost::shared_ptr<Region> find_whole_file_parent (boost::shared_ptr<Region const>) const;

	boost::shared_ptr<Region>      XMLRegionFactory (const XMLNode&, bool full);
	boost::shared_ptr<AudioRegion> XMLAudioRegionFactory (const XMLNode&, bool full);
	boost::shared_ptr<MidiRegion>  XMLMidiRegionFactory (const XMLNode&, bool full);

	/* source management */

	void import_files (ImportStatus&);
	bool sample_rate_convert (ImportStatus&, std::string infile, std::string& outfile);
	std::string build_tmp_convert_name (std::string file);

	boost::shared_ptr<ExportHandler> get_export_handler ();
	boost::shared_ptr<ExportStatus> get_export_status ();

	int start_audio_export (samplepos_t position, bool realtime = false, bool region_export = false);

	PBD::Signal1<int, samplecnt_t> ProcessExport;
	static PBD::Signal2<void,std::string, std::string> Exported;

	void add_source (boost::shared_ptr<Source>);
	void remove_source (boost::weak_ptr<Source>);

	void cleanup_regions();
	bool can_cleanup_peakfiles () const;
	int  cleanup_peakfiles ();
	int  cleanup_sources (CleanupReport&);
	int  cleanup_trash_sources (CleanupReport&);

	int destroy_sources (std::list<boost::shared_ptr<Source> > const&);

	int remove_last_capture ();
	void get_last_capture_sources (std::list<boost::shared_ptr<Source> >&);

	/** handlers should return -1 for "stop cleanup",
	    0 for "yes, delete this playlist",
	    1 for "no, don't delete this playlist".
	*/
	static PBD::Signal1<int,boost::shared_ptr<Playlist> >  AskAboutPlaylistDeletion;

	/** handlers should return 0 for "ignore the rate mismatch",
	    !0 for "do not use this session"
	*/
	static PBD::Signal2<int, samplecnt_t, samplecnt_t> AskAboutSampleRateMismatch;

	/** non interactive message */
	static PBD::Signal2<void, samplecnt_t, samplecnt_t> NotifyAboutSampleRateMismatch;

	/** handlers should return !0 for use pending state, 0 for ignore it.
	 */
	static PBD::Signal0<int> AskAboutPendingState;

	boost::shared_ptr<AudioFileSource> create_audio_source_for_session (
		size_t, std::string const &, uint32_t);

	boost::shared_ptr<MidiSource> create_midi_source_for_session (std::string const &);
	boost::shared_ptr<MidiSource> create_midi_source_by_stealing_name (boost::shared_ptr<Track>);

	boost::shared_ptr<Source> source_by_id (const PBD::ID&);
	boost::shared_ptr<AudioFileSource> audio_source_by_path_and_channel (const std::string&, uint16_t) const;
	boost::shared_ptr<MidiSource> midi_source_by_path (const std::string&, bool need_source_lock) const;
	uint32_t count_sources_by_origin (const std::string&);

	void add_playlist (boost::shared_ptr<Playlist>, bool unused = false);

	/* Curves and AutomationLists (TODO when they go away) */
	void add_automation_list(AutomationList*);

	/* auditioning */

	boost::shared_ptr<Auditioner> the_auditioner() { return auditioner; }
	void audition_playlist ();
	void audition_region (boost::shared_ptr<Region>);
	void cancel_audition ();
	bool is_auditioning () const;

	PBD::Signal1<void,bool> AuditionActive;

	/* session script */
	void register_lua_function (const std::string&, const std::string&, const LuaScriptParamList&);
	void unregister_lua_function (const std::string& name);
	std::vector<std::string> registered_lua_functions ();
	uint32_t registered_lua_function_count () const { return _n_lua_scripts; }
	void scripts_changed (); // called from lua, updates _n_lua_scripts

	PBD::Signal0<void> LuaScriptsChanged;

	/* flattening stuff */

	boost::shared_ptr<Region> write_one_track (Track&, samplepos_t start, samplepos_t end,
	                                           bool overwrite, std::vector<boost::shared_ptr<Source> >&, InterThreadInfo& wot,
	                                           boost::shared_ptr<Processor> endpoint,
	                                           bool include_endpoint, bool for_export, bool for_freeze);
	int freeze_all (InterThreadInfo&);

	/* session-wide solo/mute/rec-enable */

	bool muted() const;
	std::vector<boost::weak_ptr<AutomationControl> > cancel_all_mute ();

	bool soloing() const { return _non_soloed_outs_muted; }
	bool listening() const { return _listen_cnt > 0; }
	bool solo_isolated() const { return _solo_isolated_cnt > 0; }
	void cancel_all_solo ();

	bool solo_selection_active();
	void solo_selection( StripableList&, bool );

	static const SessionEvent::RTeventCallback rt_cleanup;

	void clear_all_solo_state (boost::shared_ptr<RouteList>);

	/* Control-based methods */

	void set_controls (boost::shared_ptr<ControlList>, double val, PBD::Controllable::GroupControlDisposition);
	void set_control (boost::shared_ptr<AutomationControl>, double val, PBD::Controllable::GroupControlDisposition);

	void set_exclusive_input_active (boost::shared_ptr<RouteList> rt, bool onoff, bool flip_others = false);

	PBD::Signal1<void,bool> SoloActive;
	PBD::Signal0<void> SoloChanged;
	PBD::Signal0<void> MuteChanged;
	PBD::Signal0<void> IsolatedChanged;
	PBD::Signal0<void> MonitorChanged;
	PBD::Signal0<void> MonitorBusAddedOrRemoved;

	PBD::Signal0<void> session_routes_reconnected;

	/* monitor/master out */
	int add_master_bus (ChanCount const&);

	void reset_monitor_section ();
	bool monitor_active() const { return (_monitor_out && _monitor_out->monitor_control () && _monitor_out->monitor_control ()->monitor_active()); }

	boost::shared_ptr<Route> monitor_out() const { return _monitor_out; }
	boost::shared_ptr<Route> master_out() const { return _master_out; }

	PresentationInfo::order_t master_order_key () const { return _master_out ? _master_out->presentation_info ().order () : -1; }
	bool ensure_stripable_sort_order ();

	void globally_add_internal_sends (boost::shared_ptr<Route> dest, Placement p, bool);
	void globally_set_send_gains_from_track (boost::shared_ptr<Route> dest);
	void globally_set_send_gains_to_zero (boost::shared_ptr<Route> dest);
	void globally_set_send_gains_to_unity (boost::shared_ptr<Route> dest);
	void add_internal_sends (boost::shared_ptr<Route> dest, Placement p, boost::shared_ptr<RouteList> senders);
	void add_internal_send (boost::shared_ptr<Route>, int, boost::shared_ptr<Route>);
	void add_internal_send (boost::shared_ptr<Route>, boost::shared_ptr<Processor>, boost::shared_ptr<Route>);

	static void set_disable_all_loaded_plugins (bool yn) {
		_disable_all_loaded_plugins = yn;
	}
	static bool get_disable_all_loaded_plugins() {
		return _disable_all_loaded_plugins;
	}
	static void set_bypass_all_loaded_plugins (bool yn) {
		_bypass_all_loaded_plugins = yn;
	}
	static bool get_bypass_all_loaded_plugins() {
		return _bypass_all_loaded_plugins;
	}

	uint32_t next_send_id();
	uint32_t next_aux_send_id();
	uint32_t next_return_id();
	uint32_t next_insert_id();
	void mark_send_id (uint32_t);
	void mark_aux_send_id (uint32_t);
	void mark_return_id (uint32_t);
	void mark_insert_id (uint32_t);
	void unmark_send_id (uint32_t);
	void unmark_aux_send_id (uint32_t);
	void unmark_return_id (uint32_t);
	void unmark_insert_id (uint32_t);

	/* s/w "RAID" management */

	boost::optional<samplecnt_t> available_capture_duration();

	/* I/O bundles */

	void add_bundle (boost::shared_ptr<Bundle>, bool emit_signal = true);
	void remove_bundle (boost::shared_ptr<Bundle>);
	boost::shared_ptr<Bundle> bundle_by_name (std::string) const;

	PBD::Signal0<void> BundleAddedOrRemoved;

	void midi_panic ();

	/* History (for editors, mixers, UIs etc.) */

	/** Undo some transactions.
	 * @param n Number of transactions to undo.
	 */
	void undo (uint32_t n);
	/** Redo some transactions.
	 * @param n Number of transactions to undo.
	 */
	void redo (uint32_t n);

	UndoHistory& history() { return _history; }

	uint32_t undo_depth() const { return _history.undo_depth(); }
	uint32_t redo_depth() const { return _history.redo_depth(); }
	std::string next_undo() const { return _history.next_undo(); }
	std::string next_redo() const { return _history.next_redo(); }

	/** begin collecting undo information
	 *
	 * This call must always be followed by either
	 * begin_reversible_command() or commit_reversible_command()
	 *
	 * @param cmd_name human readable name for the undo operation
	 */
	void begin_reversible_command (const std::string& cmd_name);
	void begin_reversible_command (GQuark);
	/** abort an open undo command
	 * This must only be called after begin_reversible_command ()
	 */
	void abort_reversible_command ();
	/** finalize an undo command and commit pending transactions
	 *
	 * This must only be called after begin_reversible_command ()
	 * @param cmd (additional) command to add
	 */
	void commit_reversible_command (Command* cmd = 0);

	void add_command (Command *const cmd);

	/** create an StatefulDiffCommand from the given object and add it to the stack.
	 *
	 * This function must only be called after  begin_reversible_command.
	 * Failing to do so may lead to a crash.
	 *
	 * @param sfd the object to diff
	 * @returns the allocated StatefulDiffCommand (already added via add_command)
	 */
	PBD::StatefulDiffCommand* add_stateful_diff_command (boost::shared_ptr<PBD::StatefulDestructible> sfd);

	/** @return The list of operations that are currently in progress */
	std::list<GQuark> const & current_operations () {
		return _current_trans_quarks;
	}

	bool operation_in_progress (GQuark) const;

	void add_commands (std::vector<Command*> const & cmds);

	std::map<PBD::ID,PBD::StatefulDestructible*> registry;

	// these commands are implemented in libs/ardour/session_command.cc
	Command* memento_command_factory(XMLNode* n);
	Command* stateful_diff_command_factory (XMLNode *);
	void register_with_memento_command_factory(PBD::ID, PBD::StatefulDestructible*);

	/* clicking */

	boost::shared_ptr<IO> click_io() { return _click_io; }
	boost::shared_ptr<Amp> click_gain() { return _click_gain; }

	/* disk, buffer loads */

	uint32_t playback_load ();
	uint32_t capture_load ();

	/* ranges */

	void request_play_range (std::list<AudioRange>*, bool leave_rolling = false);
	void request_cancel_play_range ();
	bool get_play_range () const { return _play_range; }

	void maybe_update_session_range (samplepos_t, samplepos_t);

	/* preroll */
	samplecnt_t preroll_samples (samplepos_t) const;

	void request_preroll_record_trim (samplepos_t start, samplecnt_t preroll);
	void request_count_in_record ();

	samplecnt_t preroll_record_trim_len () const { return _preroll_record_trim_len; }

	/* temporary hacks to allow selection to be pushed from GUI into backend.
	   Whenever we move the selection object into libardour, these will go away.
	 */
	void set_range_selection (samplepos_t start, samplepos_t end);
	void set_object_selection (samplepos_t start, samplepos_t end);
	void clear_range_selection ();
	void clear_object_selection ();

	/* buffers for gain and pan */

	gain_t* gain_automation_buffer () const;
	gain_t* trim_automation_buffer () const;
	gain_t* send_gain_automation_buffer () const;
	gain_t* scratch_automation_buffer () const;
	pan_t** pan_automation_buffer () const;

	void ensure_buffer_set (BufferSet& buffers, const ChanCount& howmany);

	/* VST support */

	static int  vst_current_loading_id;
	static const char* vst_can_do_strings[];
	static const int vst_can_do_string_count;

	static intptr_t vst_callback (
		AEffect* effect,
		int32_t opcode,
		int32_t index,
		intptr_t value,
		void* ptr,
		float opt
		);

	static PBD::Signal0<void> SendFeedback;

	/* Speakers */

	boost::shared_ptr<Speakers> get_speakers ();

	/* Controllables */

	boost::shared_ptr<Processor> processor_by_id (PBD::ID) const;

	boost::shared_ptr<PBD::Controllable> controllable_by_id (const PBD::ID&);
	boost::shared_ptr<AutomationControl> automation_control_by_id (const PBD::ID&);

	void add_controllable (boost::shared_ptr<PBD::Controllable>);

	boost::shared_ptr<PBD::Controllable> solo_cut_control() const;

	SessionConfiguration config;

	SessionConfiguration* cfg () { return &config; }

	bool exporting () const {
		return _exporting;
	}

	bool realtime_export() const {
		return _realtime_export;
	}

	bool bounce_processing() const {
		return _bounce_processing_active;
	}

	/* this is a private enum, but setup_enum_writer() needs it,
	   and i can't find a way to give that function
	   friend access. sigh.
	*/

	enum PostTransportWork {
		PostTransportStop               = 0x1,
		PostTransportLocate             = 0x2,
		PostTransportRoll               = 0x4,
		PostTransportAbort              = 0x8,
		PostTransportOverWrite          = 0x10,
		PostTransportAudition           = 0x20,
		PostTransportReverse            = 0x40,
		PostTransportClearSubstate      = 0x80,
		PostTransportAdjustPlaybackBuffering  = 0x100,
		PostTransportAdjustCaptureBuffering   = 0x200
	};

	boost::shared_ptr<SessionPlaylists> playlists () const { return _playlists; }

	void send_mmc_locate (samplepos_t);
	void queue_full_time_code () { _send_timecode_update = true; }
	void queue_song_position_pointer () { /* currently does nothing */ }

	bool step_editing() const { return (_step_editors > 0); }

	void request_suspend_timecode_transmission ();
	void request_resume_timecode_transmission ();
	bool timecode_transmission_suspended () const;

	std::vector<std::string> source_search_path(DataType) const;
	void ensure_search_path_includes (const std::string& path, DataType type);
	void remove_dir_from_search_path (const std::string& path, DataType type);

	std::list<std::string> unknown_processors () const;

	std::list<std::string> missing_filesources (DataType) const;

	/** Emitted when a feedback cycle has been detected within Ardour's signal
	    processing path.  Until it is fixed (by the user) some (unspecified)
	    routes will not be run.
	*/
	static PBD::Signal0<void> FeedbackDetected;

	/** Emitted when a graph sort has successfully completed, which means
	    that it has no feedback cycles.
	*/
	static PBD::Signal0<void> SuccessfulGraphSort;

	/* handlers can return an integer value:
	   0: config.set_audio_search_path() or config.set_midi_search_path() was used
	   to modify the search path and we should try to find it again.
	   1: quit entire session load
	   2: as 0, but don't ask about other missing files
	   3: don't ask about other missing files, and just mark this one missing
	   -1: just mark this one missing
	   any other value: as -1
	*/
	static PBD::Signal3<int,Session*,std::string,DataType> MissingFile;

	void set_missing_file_replacement (const std::string& mfr) {
		_missing_file_replacement = mfr;
	}

	/** Emitted when the session wants Ardour to quit */
	static PBD::Signal0<void> Quit;

	/** Emitted when Ardour is asked to load a session in an older session
	 * format, and makes a backup copy.
	 */
	static PBD::Signal2<void,std::string,std::string> VersionMismatch;

	SceneChanger* scene_changer() const { return _scene_changer; }

	/* asynchronous MIDI control ports */

	boost::shared_ptr<Port> mmc_output_port () const;
	boost::shared_ptr<Port> mmc_input_port () const;
	boost::shared_ptr<Port> scene_input_port () const;
	boost::shared_ptr<Port> scene_output_port () const;

	boost::shared_ptr<AsyncMIDIPort> vkbd_output_port () const;

	/* synchronous MIDI ports used for synchronization */

	boost::shared_ptr<MidiPort> midi_clock_output_port () const;
	boost::shared_ptr<MidiPort> mtc_output_port () const;
	boost::shared_ptr<Port> ltc_output_port() const { return _ltc_output_port; }

	MIDI::MachineControl& mmc() { return *_mmc; }

	void reconnect_midi_scene_ports (bool);
	void reconnect_mmc_ports (bool);

	void reconnect_ltc_output ();

	VCAManager& vca_manager() { return *_vca_manager; }
	VCAManager* vca_manager_ptr() { return _vca_manager; }

	void auto_connect_thread_wakeup ();

	double compute_speed_from_master (pframes_t nframes);
	bool   transport_master_is_external() const;
	bool   transport_master_no_external_or_using_engine() const;
	boost::shared_ptr<TransportMaster> transport_master() const;

	void import_pt (PTFFormat& ptf, ImportStatus& status);
	bool import_sndfile_as_region (std::string path, SrcQuality quality, samplepos_t& pos, SourceList& sources, ImportStatus& status);

protected:
	friend class AudioEngine;
	void set_block_size (pframes_t nframes);
	void set_sample_rate (samplecnt_t nframes);

	friend class Route;
	void update_latency_compensation (bool force, bool called_from_backend);

	/* transport API */

	void locate (samplepos_t, bool with_roll, bool with_flush, bool for_loop_end=false, bool force=false, bool with_mmc=true);
	void stop_transport (bool abort = false, bool clear_state = false);
	void start_transport ();
	void butler_completed_transport_work ();
	void post_locate ();
	void schedule_butler_for_transport_work ();
	bool should_roll_after_locate () const;
	double speed() const { return _transport_speed; }
	samplepos_t position() const { return _transport_sample; }
	void set_transport_speed (double speed, bool abort, bool clear_state, bool as_default);

private:
	int  create (const std::string& mix_template, BusProfile const *, bool unnamed);
	void destroy ();

	static guint _name_id_counter;
	static void init_name_id_counter (guint n);
	static unsigned int name_id_counter ();

	boost::shared_ptr<SessionPlaylists> _playlists;

	/* stuff used in process() should be close together to
	   maximise cache hits
	*/

	typedef void (Session::*process_function_type)(pframes_t);

	AudioEngine&            _engine;
	mutable gint             processing_prohibited;
	process_function_type    process_function;
	process_function_type    last_process_function;
	bool                    _bounce_processing_active;
	bool                     waiting_for_sync_offset;
	samplecnt_t             _base_sample_rate;     // sample-rate of the session at creation time, "native" SR
	samplecnt_t             _nominal_sample_rate;  // overridden by audioengine setting
	samplecnt_t             _current_sample_rate;  // this includes video pullup offset
	mutable gint            _record_status;
	samplepos_t             _transport_sample;
	gint                    _seek_counter;
	Location*               _session_range_location; ///< session range, or 0 if there is nothing in the session yet
	bool                    _session_range_is_free;
	bool                    _silent;
	samplecnt_t             _remaining_latency_preroll;

	// varispeed playback -- TODO: move out of session to backend.
	double                  _engine_speed;
	double                  _transport_speed; // only: -1, 0, +1
	double                  _default_transport_speed;
	double                  _last_transport_speed;
	double                  _signalled_varispeed;
	double                  _target_transport_speed;

	bool                     auto_play_legal;
	samplepos_t             _requested_return_sample;
	pframes_t                current_block_size;
	samplecnt_t             _worst_output_latency;
	samplecnt_t             _worst_input_latency;
	samplecnt_t             _worst_route_latency;
	uint32_t                _send_latency_changes;
	bool                    _have_captured;
	bool                    _non_soloed_outs_muted;
	bool                    _listening;
	uint32_t                _listen_cnt;
	uint32_t                _solo_isolated_cnt;
	bool                    _writable;
	bool                    _was_seamless;
	bool                    _under_nsm_control;
	unsigned int            _xrun_count;

	std::string             _missing_file_replacement;

	void add_monitor_section ();
	void remove_monitor_section ();

	void update_latency (bool playback);
	bool update_route_latency (bool reverse, bool apply_to_delayline, bool* delayline_update_needed);
	void initialize_latencies ();
	void set_worst_output_latency ();
	void set_worst_input_latency ();

	void send_latency_compensation_change ();

	void ensure_buffers (ChanCount howmany = ChanCount::ZERO);

	void process_scrub          (pframes_t);
	void process_without_events (pframes_t);
	void process_with_events    (pframes_t);
	void process_audition       (pframes_t);
	void process_export         (pframes_t);
	void process_export_fw      (pframes_t);

	samplecnt_t calc_preroll_subcycle (samplecnt_t) const;

	void block_processing() { g_atomic_int_set (&processing_prohibited, 1); }
	void unblock_processing() { g_atomic_int_set (&processing_prohibited, 0); }
	bool processing_blocked() const { return g_atomic_int_get (&processing_prohibited); }

	static const samplecnt_t bounce_chunk_size;

	/* Transport master DLL */

	enum TransportMasterState {
		Stopped, /* no incoming or invalid signal/data for master to run with */
		Waiting, /* waiting to get full lock on incoming signal/data */
		Running  /* lock achieved, master is generating meaningful speed & position */
	};

	samplepos_t master_wait_end;

	enum TransportMasterAction {
		TransportMasterRelax,
		TransportMasterNoRoll,
		TransportMasterLocate,
		TransportMasterStart,
		TransportMasterStop,
		TransportMasterWait,
	};

	struct TransportMasterStrategy {
		TransportMasterAction action;
		samplepos_t target;
		LocateTransportDisposition roll_disposition;
		double catch_speed;

		TransportMasterStrategy ()
			: action (TransportMasterRelax)
			, target (0)
			, roll_disposition (MustStop)
			, catch_speed (0.) {}
	};

	TransportMasterStrategy transport_master_strategy;
	double plan_master_strategy (pframes_t nframes, double master_speed, samplepos_t master_transport_sample, double catch_speed);
	double plan_master_strategy_engine (pframes_t nframes, double master_speed, samplepos_t master_transport_sample, double catch_speed);
	bool implement_master_strategy ();

	bool follow_transport_master (pframes_t nframes);

	void sync_source_changed (SyncSource, samplepos_t pos, pframes_t cycle_nframes);

	bool post_export_sync;
	samplepos_t post_export_position;

	bool _exporting;
	bool _export_rolling;
	bool _realtime_export;
	bool _region_export;
	samplepos_t _export_preroll;

	boost::shared_ptr<ExportHandler> export_handler;
	boost::shared_ptr<ExportStatus>  export_status;

	int  pre_export ();
	int  stop_audio_export ();
	void finalize_audio_export (TransportRequestSource trs);
	void finalize_export_internal (bool stop_freewheel);
	bool _pre_export_mmc_enabled;

	PBD::ScopedConnection export_freewheel_connection;

	void get_track_statistics ();
	int  process_routes (pframes_t, bool& need_butler);
	int  silent_process_routes (pframes_t, bool& need_butler);

	/** @return 1 if there is a pending declick fade-in,
	    -1 if there is a pending declick fade-out,
	    0 if there is no pending declick.
	*/
	bool maybe_stop (samplepos_t limit);
	bool maybe_sync_start (pframes_t &);

	std::string             _path;
	std::string             _name;
	bool                    _is_new;
	bool                    _send_qf_mtc;
	/** Number of process samples since the last MTC output (when sending MTC); used to
	 *  know when to send full MTC messages every so often.
	 */
	pframes_t               _pframes_since_last_mtc;
	bool                     play_loop;
	bool                     loop_changing;
	samplepos_t              last_loopend;

	boost::scoped_ptr<SessionDirectory> _session_dir;

	void hookup_io ();
	void graph_reordered (bool called_from_backend);

	/** current snapshot name, without the .ardour suffix */
	void set_snapshot_name (const std::string &);
	void save_snapshot_name (const std::string &);
	std::string _current_snapshot_name;

	XMLTree*         state_tree;
	bool             state_was_pending;
	StateOfTheState _state_of_the_state;

	friend class    StateProtector;
	gint            _suspend_save; /* atomic */
	volatile bool   _save_queued;
	volatile bool   _save_queued_pending;

	Glib::Threads::Mutex save_state_lock;
	Glib::Threads::Mutex save_source_lock;
	Glib::Threads::Mutex peak_cleanup_lock;

	int        load_options (const XMLNode&);
	int        load_state (std::string snapshot_name, bool from_template = false);
	static int parse_stateful_loading_version (const std::string&);

	samplepos_t _last_roll_location;
	/** the session sample time at which we last rolled, located, or changed transport direction */
	samplepos_t _last_roll_or_reversal_location;
	samplepos_t _last_record_location;

	bool              pending_abort;
	bool              pending_auto_loop;

	PBD::ReallocPool _mempool;
	LuaState lua;
	Glib::Threads::Mutex lua_lock;
	luabridge::LuaRef * _lua_run;
	luabridge::LuaRef * _lua_add;
	luabridge::LuaRef * _lua_del;
	luabridge::LuaRef * _lua_list;
	luabridge::LuaRef * _lua_load;
	luabridge::LuaRef * _lua_save;
	luabridge::LuaRef * _lua_cleanup;
	uint32_t            _n_lua_scripts;

	void setup_lua ();
	void try_run_lua (pframes_t);

	Butler* _butler;

	TransportFSM* _transport_fsm;

	static const PostTransportWork ProcessCannotProceedMask = PostTransportWork (PostTransportAudition| PostTransportClearSubstate);

	gint _post_transport_work; /* accessed only atomic ops */
	PostTransportWork post_transport_work() const        { return (PostTransportWork) g_atomic_int_get (const_cast<gint*>(&_post_transport_work)); }
	void set_post_transport_work (PostTransportWork ptw) { g_atomic_int_set (&_post_transport_work, (gint) ptw); }
	void add_post_transport_work (PostTransportWork ptw);

	void schedule_playback_buffering_adjustment ();
	void schedule_capture_buffering_adjustment ();

	Locations*       _locations;
	void location_added (Location*);
	void location_removed (Location*);
	void locations_changed ();
	void _locations_changed (const Locations::LocationList&);

	void update_skips (Location*, bool consolidate);
	void update_marks (Location* loc);
	void consolidate_skips (Location*);
	void sync_locations_to_skips ();
	void _sync_locations_to_skips ();

	PBD::ScopedConnectionList skip_update_connections;
	bool _ignore_skips_updates;

	PBD::ScopedConnectionList punch_connections;
	void             auto_punch_start_changed (Location *);
	void             auto_punch_end_changed (Location *);
	void             auto_punch_changed (Location *);

	PBD::ScopedConnectionList loop_connections;
	void             auto_loop_changed (Location *);

	void pre_engine_init (std::string path);
	int  post_engine_init ();
	int  immediately_post_engine ();
	void remove_empty_sounds ();

	void session_loaded ();

	void setup_midi_control ();
	int  midi_read (MIDI::Port *);

	void enable_record ();

	void increment_transport_position (samplecnt_t val) {
		if (max_samplepos - val < _transport_sample) {
			_transport_sample = max_samplepos;
		} else {
			_transport_sample += val;
		}
	}

	void decrement_transport_position (samplecnt_t val) {
		if (val < _transport_sample) {
			_transport_sample -= val;
		} else {
			_transport_sample = 0;
		}
	}

	void post_transport_motion ();
	static void *session_loader_thread (void *arg);

	void *do_work();

	/* Signal Forwarding */
	void emit_route_signals ();
	void emit_thread_run ();
	static void *emit_thread (void *);
	void emit_thread_start ();
	void emit_thread_terminate ();

	pthread_t       _rt_emit_thread;
	bool            _rt_thread_active;

	pthread_mutex_t _rt_emit_mutex;
	pthread_cond_t  _rt_emit_cond;
	bool            _rt_emit_pending;

	/* Auto Connect Thread */
	static void *auto_connect_thread (void *);
	void auto_connect_thread_run ();
	void auto_connect_thread_start ();
	void auto_connect_thread_terminate ();

	pthread_t       _auto_connect_thread;
	gint            _ac_thread_active;
	pthread_mutex_t _auto_connect_mutex;
	pthread_cond_t  _auto_connect_cond;

	struct AutoConnectRequest {
		public:
		AutoConnectRequest (boost::shared_ptr <Route> r, bool ci,
				const ChanCount& is,
				const ChanCount& os,
				const ChanCount& io,
				const ChanCount& oo)
			: route (boost::weak_ptr<Route> (r))
			, connect_inputs (ci)
			, input_start (is)
			, output_start (os)
			, input_offset (io)
			, output_offset (oo)
		{}

		boost::weak_ptr <Route> route;
		bool connect_inputs;
		ChanCount input_start;
		ChanCount output_start;
		ChanCount input_offset;
		ChanCount output_offset;
	};

	Glib::Threads::Mutex  _update_latency_lock;

	typedef std::queue<AutoConnectRequest> AutoConnectQueue;
	Glib::Threads::Mutex  _auto_connect_queue_lock;
	AutoConnectQueue _auto_connect_queue;
	guint _latency_recompute_pending;

	void get_physical_ports (std::vector<std::string>& inputs, std::vector<std::string>& outputs, DataType type,
	                         MidiPortFlags include = MidiPortFlags (0),
	                         MidiPortFlags exclude = MidiPortFlags (0));

	void auto_connect (const AutoConnectRequest&);
	void queue_latency_recompute ();

	/* SessionEventManager interface */

	void process_event (SessionEvent*);
	void set_next_event ();
	void cleanup_event (SessionEvent*,int);

	/* MIDI Machine Control */

	void spp_start ();
	void spp_continue ();
	void spp_stop ();

	void mmc_deferred_play (MIDI::MachineControl &);
	void mmc_stop (MIDI::MachineControl &);
	void mmc_step (MIDI::MachineControl &, int);
	void mmc_pause (MIDI::MachineControl &);
	void mmc_record_pause (MIDI::MachineControl &);
	void mmc_record_strobe (MIDI::MachineControl &);
	void mmc_record_exit (MIDI::MachineControl &);
	void mmc_track_record_status (MIDI::MachineControl &, uint32_t track, bool enabled);
	void mmc_fast_forward (MIDI::MachineControl &);
	void mmc_rewind (MIDI::MachineControl &);
	void mmc_locate (MIDI::MachineControl &, const MIDI::byte *);
	void mmc_shuttle (MIDI::MachineControl &mmc, float speed, bool forw);
	void mmc_record_enable (MIDI::MachineControl &mmc, size_t track, bool enabled);

	struct timeval last_mmc_step;
	double step_speed;

	typedef boost::function<bool()> MidiTimeoutCallback;
	typedef std::list<MidiTimeoutCallback> MidiTimeoutList;

	MidiTimeoutList midi_timeouts;
	bool mmc_step_timeout ();
	void send_immediate_mmc (MIDI::MachineControlCommand);

	MIDI::byte mtc_msg[16];
	MIDI::byte mtc_timecode_bits;   /* encoding of SMTPE type for MTC */
	MIDI::byte midi_msg[16];
	double outbound_mtc_timecode_frame;
	Timecode::Time transmitting_timecode_time;
	int next_quarter_frame_to_send;

	double _samples_per_timecode_frame; /* has to be floating point because of drop sample */
	samplecnt_t _frames_per_hour;
	samplecnt_t _timecode_frames_per_hour;

	/* cache the most-recently requested time conversions. This helps when we
	 * have multiple clocks showing the same time (e.g. the transport sample) */
	bool last_timecode_valid;
	samplepos_t last_timecode_when;
	Timecode::Time last_timecode;

	bool _send_timecode_update; ///< Flag to send a full sample (Timecode) MTC message this cycle

	int send_midi_time_code_for_cycle (samplepos_t, samplepos_t, pframes_t nframes);

	LTCEncoder*       ltc_encoder;
	ltcsnd_sample_t*  ltc_enc_buf;

	Timecode::TimecodeFormat ltc_enc_tcformat;
	int32_t           ltc_buf_off;
	int32_t           ltc_buf_len;

	double            ltc_speed;
	int32_t           ltc_enc_byte;
	samplepos_t       ltc_enc_pos;
	double            ltc_enc_cnt;
	samplepos_t       ltc_enc_off;
	bool              restarting;
	samplepos_t       ltc_prev_cycle;

	samplepos_t       ltc_timecode_offset;
	bool              ltc_timecode_negative_offset;

	LatencyRange      ltc_out_latency;

	void ltc_tx_initialize();
	void ltc_tx_cleanup();
	void ltc_tx_reset();
	void ltc_tx_resync_latency();
	void ltc_tx_recalculate_position();
	void ltc_tx_parse_offset();
	PBD::ScopedConnectionList ltc_tx_connections;

	void reset_record_status ();

	int no_roll (pframes_t nframes);
	int fail_roll (pframes_t nframes);

	bool non_realtime_work_pending() const { return static_cast<bool>(post_transport_work()); }
	bool process_can_proceed() const { return !(post_transport_work() & ProcessCannotProceedMask); }

	MidiControlUI* midi_control_ui;

	int           start_midi_thread ();

	bool should_ignore_transport_request (TransportRequestSource, TransportRequestType);

	void set_play_loop (bool yn, bool change_transport_state);
	void unset_play_loop (bool change_transport_state = false);
	void overwrite_some_buffers (boost::shared_ptr<Route>, OverwriteReason);
	void flush_all_inserts ();
	int  micro_locate (samplecnt_t distance);

	enum PunchLoopLock {
		NoConstraint,
		OnlyPunch,
		OnlyLoop,
	};

	volatile guint _punch_or_loop; // enum PunchLoopLock
	gint current_usecs_per_track;

	bool punch_active () const;
	void unset_punch ();
	void reset_punch_loop_constraint ();
	bool maybe_allow_only_loop (bool play_loop = false);
	bool maybe_allow_only_punch ();

	void force_locate (samplepos_t sample, LocateTransportDisposition);
	void realtime_stop (bool abort, bool clear_state);
	void realtime_locate (bool);
	void non_realtime_start_scrub ();
	void non_realtime_set_speed ();
	void non_realtime_locate ();
	void non_realtime_stop (bool abort, int entry_request_count, bool& finished);
	void non_realtime_overwrite (int entry_request_count, bool& finished);
	void engine_halted ();
	void engine_running ();
	void xrun_recovery ();
	void set_track_loop (bool);
	bool select_playhead_priority_target (samplepos_t&);
	void follow_playhead_priority ();

	/* These are synchronous and so can only be called from within the process
	 * cycle
	 */

	int  send_full_time_code (samplepos_t, pframes_t nframes);
	void send_song_position_pointer (samplepos_t);

	TempoMap    *_tempo_map;
	void          tempo_map_changed (const PBD::PropertyChange&);

	/* edit/mix groups */

	int load_route_groups (const XMLNode&, int);

	std::list<RouteGroup *> _route_groups;
	RouteGroup*             _all_route_group;

	/* routes stuff */

	boost::shared_ptr<Graph> _process_graph;

	SerializedRCUManager<RouteList>  routes;

	void add_routes (RouteList&, bool input_auto_connect, bool output_auto_connect, bool save, PresentationInfo::order_t);
	void add_routes_inner (RouteList&, bool input_auto_connect, bool output_auto_connect, PresentationInfo::order_t);
	bool _adding_routes_in_progress;
	bool _reconnecting_routes_in_progress;
	bool _route_deletion_in_progress;

	boost::shared_ptr<Route> XMLRouteFactory (const XMLNode&, int);
	boost::shared_ptr<Route> XMLRouteFactory_2X (const XMLNode&, int);
	boost::shared_ptr<Route> XMLRouteFactory_3X (const XMLNode&, int);

	void route_processors_changed (RouteProcessorChange);

	bool find_route_name (std::string const &, uint32_t& id, std::string& name, bool);
	void count_existing_track_channels (ChanCount& in, ChanCount& out);
	void auto_connect_route (boost::shared_ptr<Route>, bool, const ChanCount&, const ChanCount&, const ChanCount& io = ChanCount(), const ChanCount& oo = ChanCount());
	void midi_output_change_handler (IOChange change, void* /*src*/, boost::weak_ptr<Route> midi_track);

	/* track numbering */

	void reassign_track_numbers ();
	uint32_t _track_number_decimals;

	/* solo/mute/notifications */

	void route_listen_changed (PBD::Controllable::GroupControlDisposition, boost::weak_ptr<Route>);
	void route_mute_changed ();
	void route_solo_changed (bool self_solo_change, PBD::Controllable::GroupControlDisposition group_override, boost::weak_ptr<Route>);
	void route_solo_isolated_changed (boost::weak_ptr<Route>);

	void update_route_solo_state (boost::shared_ptr<RouteList> r = boost::shared_ptr<RouteList>());

	void listen_position_changed ();
	void solo_control_mode_changed ();

	/* REGION MANAGEMENT */

	mutable Glib::Threads::Mutex region_lock;

	int load_regions (const XMLNode& node);
	int load_compounds (const XMLNode& node);

	void route_added_to_route_group (RouteGroup *, boost::weak_ptr<Route>);
	void route_removed_from_route_group (RouteGroup *, boost::weak_ptr<Route>);
	void route_group_property_changed (RouteGroup *);

	/* SOURCES */

	mutable Glib::Threads::Mutex source_lock;

public:

	/* Emited when a new source is added to the session */
	PBD::Signal1< void, boost::weak_ptr<Source> > SourceAdded;
	PBD::Signal1< void, boost::weak_ptr<Source> > SourceRemoved;

	typedef std::map<PBD::ID,boost::shared_ptr<Source> > SourceMap;

	void foreach_source (boost::function<void( boost::shared_ptr<Source> )> f) {
		Glib::Threads::Mutex::Lock ls (source_lock);
		for (SourceMap::iterator i = sources.begin(); i != sources.end(); ++i) {
			f ( (*i).second );
		}
	}

	bool playlist_is_active( boost::shared_ptr<Playlist>);

private:
	void reset_write_sources (bool mark_write_complete, bool force = false);
	SourceMap sources;

	int load_sources (const XMLNode& node);
	XMLNode& get_sources_as_xml ();

	boost::shared_ptr<Source> XMLSourceFactory (const XMLNode&);

	/* PLAYLISTS */

	void remove_playlist (boost::weak_ptr<Playlist>);
	void track_playlist_changed (boost::weak_ptr<Track>);
	void playlist_region_added (boost::weak_ptr<Region>);
	void playlist_ranges_moved (std::list<Evoral::RangeMove<samplepos_t> > const &);
	void playlist_regions_extended (std::list<Evoral::Range<samplepos_t> > const &);

	/* CURVES and AUTOMATION LISTS */
	std::map<PBD::ID, AutomationList*> automation_lists;

	/** load 2.X Sessions. Diskstream-ID to playlist-name mapping */
	std::map<PBD::ID, std::string> _diskstreams_2X;

	/* DEFAULT FADE CURVES */

	float default_fade_steepness;
	float default_fade_msecs;

	/* AUDITIONING */

	boost::shared_ptr<Auditioner> auditioner;
	void set_audition (boost::shared_ptr<Region>);
	void non_realtime_set_audition ();
	boost::shared_ptr<Region> pending_audition_region;

	/* EXPORT */

	/* FLATTEN */

	int flatten_one_track (AudioTrack&, samplepos_t start, samplecnt_t cnt);

	/* INSERT AND SEND MANAGEMENT */

	boost::dynamic_bitset<uint32_t> send_bitset;
	boost::dynamic_bitset<uint32_t> aux_send_bitset;
	boost::dynamic_bitset<uint32_t> return_bitset;
	boost::dynamic_bitset<uint32_t> insert_bitset;

	/* S/W RAID */

	struct space_and_path {
		uint32_t blocks;     ///< 4kB blocks
		bool blocks_unknown; ///< true if blocks is unknown
		std::string path;

		space_and_path ()
			: blocks (0)
			, blocks_unknown (true)
		{}
	};

	struct space_and_path_ascending_cmp {
		bool operator() (space_and_path a, space_and_path b) {
			if (a.blocks_unknown != b.blocks_unknown) {
				return !a.blocks_unknown;
			}
			return a.blocks > b.blocks;
		}
	};

	void setup_raid_path (std::string path);

	std::vector<space_and_path> session_dirs;
	std::vector<space_and_path>::iterator last_rr_session_dir;
	uint32_t _total_free_4k_blocks;
	/** If this is true, _total_free_4k_blocks is not definite,
	    as one or more of the session directories' filesystems
	    could not report free space.
	*/
	bool _total_free_4k_blocks_uncertain;
	Glib::Threads::Mutex space_lock;

	bool no_questions_about_missing_files;

	std::string get_best_session_directory_for_new_audio ();

	mutable gint _playback_load;
	mutable gint _capture_load;

	/* I/O bundles */

	SerializedRCUManager<BundleList> _bundles;
	XMLNode* _bundle_xml_node;
	int load_bundles (XMLNode const &);

	UndoHistory      _history;
	/** current undo transaction, or 0 */
	UndoTransaction* _current_trans;
	/** GQuarks to describe the reversible commands that are currently in progress.
	 *  These may be nested, in which case more recently-started commands are toward
	 *  the front of the list.
	 */
	std::list<GQuark> _current_trans_quarks;

	int  backend_sync_callback (TransportState, samplepos_t);

	void process_rtop (SessionEvent*);

	enum snapshot_t {
		NormalSave,
		SnapshotKeep,
		SwitchToSnapshot
	};

	XMLNode& state (bool save_template,
	                snapshot_t snapshot_type = NormalSave,
	                bool only_used_assets = false);

	XMLNode& get_state ();
	int      set_state (const XMLNode& node, int version); // not idempotent
	XMLNode& get_template ();

	/* click track */
	typedef std::list<Click*>     Clicks;
	Clicks                        clicks;
	bool                         _clicking;
	bool                         _click_rec_only;
	boost::shared_ptr<IO>        _click_io;
	boost::shared_ptr<Amp>       _click_gain;
	Sample*                       click_data;
	Sample*                       click_emphasis_data;
	samplecnt_t                   click_length;
	samplecnt_t                   click_emphasis_length;
	mutable Glib::Threads::RWLock click_lock;

	static const Sample     default_click[];
	static const samplecnt_t default_click_length;
	static const Sample     default_click_emphasis[];
	static const samplecnt_t default_click_emphasis_length;

	Click* get_click();
	samplepos_t _clicks_cleared;
	samplecnt_t _count_in_samples;
	void setup_click_sounds (int which);
	void setup_click_sounds (Sample**, Sample const *, samplecnt_t*, samplecnt_t, std::string const &);
	void clear_clicks ();
	void click (samplepos_t start, samplecnt_t nframes);
	void run_click (samplepos_t start, samplecnt_t nframes);
	void add_click (samplepos_t pos, bool emphasis);

	/* range playback */

	std::list<AudioRange> current_audio_range;
	bool _play_range;
	void set_play_range (std::list<AudioRange>&, bool leave_rolling);
	void unset_play_range ();

	/* temporary hacks to allow selection to be pushed from GUI into backend
	   Whenever we move the selection object into libardour, these will go away.
	*/
	Evoral::Range<samplepos_t> _range_selection;
	Evoral::Range<samplepos_t> _object_selection;

	void unset_preroll_record_trim ();

	samplecnt_t _preroll_record_trim_len;
	bool _count_in_once;

	/* main outs */
	uint32_t main_outs;

	boost::shared_ptr<Route> _master_out;
	boost::shared_ptr<Route> _monitor_out;

	void auto_connect_master_bus ();

	int find_all_sources (std::string path, std::set<std::string>& result);
	int find_all_sources_across_snapshots (std::set<std::string>& result, bool exclude_this_snapshot);

	typedef std::set<boost::shared_ptr<PBD::Controllable> > Controllables;
	Glib::Threads::Mutex controllables_lock;
	Controllables controllables;

	boost::shared_ptr<PBD::Controllable> _solo_cut_control;

	void reset_native_file_format();
	bool first_file_data_format_reset;
	bool first_file_header_format_reset;

	void config_changed (std::string, bool);

	XMLNode& get_control_protocol_state ();

	void set_history_depth (uint32_t depth);

	static bool _disable_all_loaded_plugins;
	static bool _bypass_all_loaded_plugins;

	mutable bool have_looped; ///< Used in \ref audible_sample

	void update_route_record_state ();
	gint _have_rec_enabled_track;
	gint _have_rec_disabled_track;

	static int ask_about_playlist_deletion (boost::shared_ptr<Playlist>);

	/* realtime "apply to set of routes" operations */
	template<typename T> SessionEvent*
		get_rt_event (boost::shared_ptr<RouteList> rl, T targ, SessionEvent::RTeventCallback after, PBD::Controllable::GroupControlDisposition group_override,
		              void (Session::*method) (boost::shared_ptr<RouteList>, T, PBD::Controllable::GroupControlDisposition)) {
		SessionEvent* ev = new SessionEvent (SessionEvent::RealTimeOperation, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0);
		ev->rt_slot = boost::bind (method, this, rl, targ, group_override);
		ev->rt_return = after;
		ev->event_loop = PBD::EventLoop::get_event_loop_for_thread ();

		return ev;
	}

	/* specialized version realtime "apply to set of routes" operations */
	template<typename T1, typename T2> SessionEvent*
		get_rt_event (boost::shared_ptr<RouteList> rl, T1 t1arg, T2 t2arg, SessionEvent::RTeventCallback after, PBD::Controllable::GroupControlDisposition group_override,
		              void (Session::*method) (boost::shared_ptr<RouteList>, T1, T2, PBD::Controllable::GroupControlDisposition)) {
		SessionEvent* ev = new SessionEvent (SessionEvent::RealTimeOperation, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0);
		ev->rt_slot = boost::bind (method, this, rl, t1arg, t2arg, group_override);
		ev->rt_return = after;
		ev->event_loop = PBD::EventLoop::get_event_loop_for_thread ();

		return ev;
	}

	/* specialized version realtime "apply to set of controls" operations */
	SessionEvent* get_rt_event (boost::shared_ptr<ControlList> cl, double arg, PBD::Controllable::GroupControlDisposition group_override) {
		SessionEvent* ev = new SessionEvent (SessionEvent::RealTimeOperation, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0);
		ev->rt_slot = boost::bind (&Session::rt_set_controls, this, cl, arg, group_override);
		ev->rt_return = Session::rt_cleanup;
		ev->event_loop = PBD::EventLoop::get_event_loop_for_thread ();

		return ev;
	}

	void rt_set_controls (boost::shared_ptr<ControlList>, double val, PBD::Controllable::GroupControlDisposition group_override);
	void rt_clear_all_solo_state (boost::shared_ptr<RouteList>, bool yn, PBD::Controllable::GroupControlDisposition group_override);

	void setup_midi_machine_control ();

	void step_edit_status_change (bool);
	uint32_t _step_editors;

	/** true if timecode transmission by the transport is suspended, otherwise false */
	mutable gint _suspend_timecode_transmission;

	void update_locations_after_tempo_map_change (const Locations::LocationList &);

	void start_time_changed (samplepos_t);
	void end_time_changed (samplepos_t);

	void set_track_monitor_input_status (bool);
	samplepos_t compute_stop_limit () const;

	boost::shared_ptr<Speakers> _speakers;
	void load_nested_sources (const XMLNode& node);

	/** The directed graph of routes that is currently being used for audio processing
	    and solo/mute computations.
	*/
	GraphEdges _current_route_graph;

	void ensure_route_presentation_info_gap (PresentationInfo::order_t, uint32_t gap_size);

	friend class    ProcessorChangeBlocker;
	gint            _ignore_route_processor_changes; /* atomic */
	gint            _ignored_a_processor_change;

	MidiClockTicker* midi_clock;

	boost::shared_ptr<Port>  _ltc_output_port;

	boost::shared_ptr<RTTaskList> _rt_tasklist;

	/* Scene Changing */
	SceneChanger* _scene_changer;

	/* persistent, non-track related MIDI ports */
	MidiPortManager* _midi_ports;
	MIDI::MachineControl* _mmc;

	void setup_ltc ();
	void setup_click ();
	void setup_click_state (const XMLNode*);
	void setup_bundles ();

	void save_as_bring_callback (uint32_t, uint32_t, std::string);

	static const uint32_t session_end_shift;

	std::string _template_state_dir;

	VCAManager* _vca_manager;

	boost::shared_ptr<Route> get_midi_nth_route_by_id (PresentationInfo::order_t n) const;

	std::string created_with;

	void midi_track_presentation_info_changed (PBD::PropertyChange const &, boost::weak_ptr<MidiTrack>);
	void rewire_selected_midi (boost::shared_ptr<MidiTrack>);
	void rewire_midi_selection_ports ();
	boost::weak_ptr<MidiTrack> current_midi_target;

	StripableList _soloSelection;  //the items that are soloe'd during a solo-selection operation; need to unsolo after the roll

	CoreSelection* _selection;

	bool _global_locate_pending;
	boost::optional<samplepos_t> _nominal_jack_transport_sample;

	bool _had_destructive_tracks;

	std::string unnamed_file_name () const;
};


} // namespace ARDOUR

#endif /* __ardour_session_h__ */