aboutsummaryrefslogtreecommitdiff
path: root/include/qom/object.h
blob: 099a356be7a63ea540d9d6693db1c5d617b00729 (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
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
/*
 * QEMU Object Model
 *
 * Copyright IBM, Corp. 2011
 *
 * Authors:
 *  Anthony Liguori   <aliguori@us.ibm.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#ifndef QEMU_OBJECT_H
#define QEMU_OBJECT_H

#include "qapi/qapi-builtin-types.h"
#include "qemu/module.h"
#include "qom/object.h"

struct TypeImpl;
typedef struct TypeImpl *Type;

typedef struct TypeInfo TypeInfo;

typedef struct InterfaceClass InterfaceClass;
typedef struct InterfaceInfo InterfaceInfo;

#define TYPE_OBJECT "object"

/**
 * DOC:
 *
 * The QEMU Object Model provides a framework for registering user creatable
 * types and instantiating objects from those types.  QOM provides the following
 * features:
 *
 *  - System for dynamically registering types
 *  - Support for single-inheritance of types
 *  - Multiple inheritance of stateless interfaces
 *
 * <example>
 *   <title>Creating a minimal type</title>
 *      <programlisting>
 *    #include "qdev.h"
 *
 *    #define TYPE_MY_DEVICE "my-device"
 *
 *    // No new virtual functions: we can reuse the typedef for the
 *    // superclass.
 *    typedef DeviceClass MyDeviceClass;
 *    typedef struct MyDevice
 *    {
 *        DeviceState parent;
 *
 *        int reg0, reg1, reg2;
 *    } MyDevice;
 *
 *    static const TypeInfo my_device_info = {
 *        .name = TYPE_MY_DEVICE,
 *        .parent = TYPE_DEVICE,
 *        .instance_size = sizeof(MyDevice),
 *    };
 *
 *    static void my_device_register_types(void)
 *    {
 *        type_register_static(&my_device_info);
 *    }
 *
 *    type_init(my_device_register_types)
 *      </programlisting>
 * </example>
 *
 * In the above example, we create a simple type that is described by #TypeInfo.
 * #TypeInfo describes information about the type including what it inherits
 * from, the instance and class size, and constructor/destructor hooks.
 *
 * Alternatively several static types could be registered using helper macro
 * DEFINE_TYPES()
 *
 * <example>
 *      <programlisting>
 *    static const TypeInfo device_types_info[] = {
 *        {
 *            .name = TYPE_MY_DEVICE_A,
 *            .parent = TYPE_DEVICE,
 *            .instance_size = sizeof(MyDeviceA),
 *        },
 *        {
 *            .name = TYPE_MY_DEVICE_B,
 *            .parent = TYPE_DEVICE,
 *            .instance_size = sizeof(MyDeviceB),
 *        },
 *    };
 *
 *    DEFINE_TYPES(device_types_info)
 *      </programlisting>
 * </example>
 *
 * Every type has an #ObjectClass associated with it.  #ObjectClass derivatives
 * are instantiated dynamically but there is only ever one instance for any
 * given type.  The #ObjectClass typically holds a table of function pointers
 * for the virtual methods implemented by this type.
 *
 * Using object_new(), a new #Object derivative will be instantiated.  You can
 * cast an #Object to a subclass (or base-class) type using
 * object_dynamic_cast().  You typically want to define macro wrappers around
 * OBJECT_CHECK() and OBJECT_CLASS_CHECK() to make it easier to convert to a
 * specific type:
 *
 * <example>
 *   <title>Typecasting macros</title>
 *   <programlisting>
 *    #define MY_DEVICE_GET_CLASS(obj) \
 *       OBJECT_GET_CLASS(MyDeviceClass, obj, TYPE_MY_DEVICE)
 *    #define MY_DEVICE_CLASS(klass) \
 *       OBJECT_CLASS_CHECK(MyDeviceClass, klass, TYPE_MY_DEVICE)
 *    #define MY_DEVICE(obj) \
 *       OBJECT_CHECK(MyDevice, obj, TYPE_MY_DEVICE)
 *   </programlisting>
 * </example>
 *
 * Class Initialization
 * ====================
 *
 * Before an object is initialized, the class for the object must be
 * initialized.  There is only one class object for all instance objects
 * that is created lazily.
 *
 * Classes are initialized by first initializing any parent classes (if
 * necessary).  After the parent class object has initialized, it will be
 * copied into the current class object and any additional storage in the
 * class object is zero filled.
 *
 * The effect of this is that classes automatically inherit any virtual
 * function pointers that the parent class has already initialized.  All
 * other fields will be zero filled.
 *
 * Once all of the parent classes have been initialized, #TypeInfo::class_init
 * is called to let the class being instantiated provide default initialize for
 * its virtual functions.  Here is how the above example might be modified
 * to introduce an overridden virtual function:
 *
 * <example>
 *   <title>Overriding a virtual function</title>
 *      <programlisting>
 *    #include "qdev.h"
 *
 *    void my_device_class_init(ObjectClass *klass, void *class_data)
 *    {
 *        DeviceClass *dc = DEVICE_CLASS(klass);
 *        dc->reset = my_device_reset;
 *    }
 *
 *    static const TypeInfo my_device_info = {
 *        .name = TYPE_MY_DEVICE,
 *        .parent = TYPE_DEVICE,
 *        .instance_size = sizeof(MyDevice),
 *        .class_init = my_device_class_init,
 *    };
 *      </programlisting>
 * </example>
 *
 * Introducing new virtual methods requires a class to define its own
 * struct and to add a .class_size member to the #TypeInfo.  Each method
 * will also have a wrapper function to call it easily:
 *
 * <example>
 *   <title>Defining an abstract class</title>
 *      <programlisting>
 *    #include "qdev.h"
 *
 *    typedef struct MyDeviceClass
 *    {
 *        DeviceClass parent;
 *
 *        void (*frobnicate) (MyDevice *obj);
 *    } MyDeviceClass;
 *
 *    static const TypeInfo my_device_info = {
 *        .name = TYPE_MY_DEVICE,
 *        .parent = TYPE_DEVICE,
 *        .instance_size = sizeof(MyDevice),
 *        .abstract = true, // or set a default in my_device_class_init
 *        .class_size = sizeof(MyDeviceClass),
 *    };
 *
 *    void my_device_frobnicate(MyDevice *obj)
 *    {
 *        MyDeviceClass *klass = MY_DEVICE_GET_CLASS(obj);
 *
 *        klass->frobnicate(obj);
 *    }
 *      </programlisting>
 * </example>
 *
 * Interfaces
 * ==========
 *
 * Interfaces allow a limited form of multiple inheritance.  Instances are
 * similar to normal types except for the fact that are only defined by
 * their classes and never carry any state.  As a consequence, a pointer to
 * an interface instance should always be of incomplete type in order to be
 * sure it cannot be dereferenced.  That is, you should define the
 * 'typedef struct SomethingIf SomethingIf' so that you can pass around
 * ``SomethingIf *si`` arguments, but not define a ``struct SomethingIf { ... }``.
 * The only things you can validly do with a ``SomethingIf *`` are to pass it as
 * an argument to a method on its corresponding SomethingIfClass, or to
 * dynamically cast it to an object that implements the interface.
 *
 * Methods
 * =======
 *
 * A <emphasis>method</emphasis> is a function within the namespace scope of
 * a class. It usually operates on the object instance by passing it as a
 * strongly-typed first argument.
 * If it does not operate on an object instance, it is dubbed
 * <emphasis>class method</emphasis>.
 *
 * Methods cannot be overloaded. That is, the #ObjectClass and method name
 * uniquely identity the function to be called; the signature does not vary
 * except for trailing varargs.
 *
 * Methods are always <emphasis>virtual</emphasis>. Overriding a method in
 * #TypeInfo.class_init of a subclass leads to any user of the class obtained
 * via OBJECT_GET_CLASS() accessing the overridden function.
 * The original function is not automatically invoked. It is the responsibility
 * of the overriding class to determine whether and when to invoke the method
 * being overridden.
 *
 * To invoke the method being overridden, the preferred solution is to store
 * the original value in the overriding class before overriding the method.
 * This corresponds to |[ {super,base}.method(...) ]| in Java and C#
 * respectively; this frees the overriding class from hardcoding its parent
 * class, which someone might choose to change at some point.
 *
 * <example>
 *   <title>Overriding a virtual method</title>
 *      <programlisting>
 *    typedef struct MyState MyState;
 *
 *    typedef void (*MyDoSomething)(MyState *obj);
 *
 *    typedef struct MyClass {
 *        ObjectClass parent_class;
 *
 *        MyDoSomething do_something;
 *    } MyClass;
 *
 *    static void my_do_something(MyState *obj)
 *    {
 *        // do something
 *    }
 *
 *    static void my_class_init(ObjectClass *oc, void *data)
 *    {
 *        MyClass *mc = MY_CLASS(oc);
 *
 *        mc->do_something = my_do_something;
 *    }
 *
 *    static const TypeInfo my_type_info = {
 *        .name = TYPE_MY,
 *        .parent = TYPE_OBJECT,
 *        .instance_size = sizeof(MyState),
 *        .class_size = sizeof(MyClass),
 *        .class_init = my_class_init,
 *    };
 *
 *    typedef struct DerivedClass {
 *        MyClass parent_class;
 *
 *        MyDoSomething parent_do_something;
 *    } DerivedClass;
 *
 *    static void derived_do_something(MyState *obj)
 *    {
 *        DerivedClass *dc = DERIVED_GET_CLASS(obj);
 *
 *        // do something here
 *        dc->parent_do_something(obj);
 *        // do something else here
 *    }
 *
 *    static void derived_class_init(ObjectClass *oc, void *data)
 *    {
 *        MyClass *mc = MY_CLASS(oc);
 *        DerivedClass *dc = DERIVED_CLASS(oc);
 *
 *        dc->parent_do_something = mc->do_something;
 *        mc->do_something = derived_do_something;
 *    }
 *
 *    static const TypeInfo derived_type_info = {
 *        .name = TYPE_DERIVED,
 *        .parent = TYPE_MY,
 *        .class_size = sizeof(DerivedClass),
 *        .class_init = derived_class_init,
 *    };
 *      </programlisting>
 * </example>
 *
 * Alternatively, object_class_by_name() can be used to obtain the class and
 * its non-overridden methods for a specific type. This would correspond to
 * ``MyClass::method(...)`` in C++.
 *
 * The first example of such a QOM method was #CPUClass.reset,
 * another example is #DeviceClass.realize.
 *
 * Standard type declaration and definition macros
 * ===============================================
 *
 * A lot of the code outlined above follows a standard pattern and naming
 * convention. To reduce the amount of boilerplate code that needs to be
 * written for a new type there are two sets of macros to generate the
 * common parts in a standard format.
 *
 * A type is declared using the OBJECT_DECLARE macro family. In types
 * which do not require any virtual functions in the class, the
 * OBJECT_DECLARE_SIMPLE_TYPE macro is suitable, and is commonly placed
 * in the header file:
 *
 * <example>
 *   <title>Declaring a simple type</title>
 *   <programlisting>
 *     OBJECT_DECLARE_SIMPLE_TYPE(MyDevice, my_device, MY_DEVICE, DEVICE)
 *   </programlisting>
 * </example>
 *
 * This is equivalent to the following:
 *
 * <example>
 *   <title>Expansion from declaring a simple type</title>
 *   <programlisting>
 *     typedef struct MyDevice MyDevice;
 *     typedef struct MyDeviceClass MyDeviceClass;
 *
 *     G_DEFINE_AUTOPTR_CLEANUP_FUNC(MyDeviceClass, object_unref)
 *
 *     #define MY_DEVICE_GET_CLASS(void *obj) \
 *             OBJECT_GET_CLASS(MyDeviceClass, obj, TYPE_MY_DEVICE)
 *     #define MY_DEVICE_CLASS(void *klass) \
 *             OBJECT_CLASS_CHECK(MyDeviceClass, klass, TYPE_MY_DEVICE)
 *     #define MY_DEVICE(void *obj)
 *             OBJECT_CHECK(MyDevice, obj, TYPE_MY_DEVICE)
 *
 *     struct MyDeviceClass {
 *         DeviceClass parent_class;
 *     };
 *   </programlisting>
 * </example>
 *
 * The 'struct MyDevice' needs to be declared separately.
 * If the type requires virtual functions to be declared in the class
 * struct, then the alternative OBJECT_DECLARE_TYPE() macro can be
 * used. This does the same as OBJECT_DECLARE_SIMPLE_TYPE(), but without
 * the 'struct MyDeviceClass' definition.
 *
 * To implement the type, the OBJECT_DEFINE macro family is available.
 * In the simple case the OBJECT_DEFINE_TYPE macro is suitable:
 *
 * <example>
 *   <title>Defining a simple type</title>
 *   <programlisting>
 *     OBJECT_DEFINE_TYPE(MyDevice, my_device, MY_DEVICE, DEVICE)
 *   </programlisting>
 * </example>
 *
 * This is equivalent to the following:
 *
 * <example>
 *   <title>Expansion from defining a simple type</title>
 *   <programlisting>
 *     static void my_device_finalize(Object *obj);
 *     static void my_device_class_init(ObjectClass *oc, void *data);
 *     static void my_device_init(Object *obj);
 *
 *     static const TypeInfo my_device_info = {
 *         .parent = TYPE_DEVICE,
 *         .name = TYPE_MY_DEVICE,
 *         .instance_size = sizeof(MyDevice),
 *         .instance_init = my_device_init,
 *         .instance_finalize = my_device_finalize,
 *         .class_size = sizeof(MyDeviceClass),
 *         .class_init = my_device_class_init,
 *     };
 *
 *     static void
 *     my_device_register_types(void)
 *     {
 *         type_register_static(&my_device_info);
 *     }
 *     type_init(my_device_register_types);
 *   </programlisting>
 * </example>
 *
 * This is sufficient to get the type registered with the type
 * system, and the three standard methods now need to be implemented
 * along with any other logic required for the type.
 *
 * If the type needs to implement one or more interfaces, then the
 * OBJECT_DEFINE_TYPE_WITH_INTERFACES() macro can be used instead.
 * This accepts an array of interface type names.
 *
 * <example>
 *   <title>Defining a simple type implementing interfaces</title>
 *   <programlisting>
 *     OBJECT_DEFINE_TYPE_WITH_INTERFACES(MyDevice, my_device,
 *                                        MY_DEVICE, DEVICE,
 *                                        { TYPE_USER_CREATABLE }, { NULL })
 *   </programlisting>
 * </example>
 *
 * If the type is not intended to be instantiated, then then
 * the OBJECT_DEFINE_ABSTRACT_TYPE() macro can be used instead:
 *
 * <example>
 *   <title>Defining a simple type</title>
 *   <programlisting>
 *     OBJECT_DEFINE_ABSTRACT_TYPE(MyDevice, my_device, MY_DEVICE, DEVICE)
 *   </programlisting>
 * </example>
 */


typedef struct ObjectProperty ObjectProperty;

/**
 * ObjectPropertyAccessor:
 * @obj: the object that owns the property
 * @v: the visitor that contains the property data
 * @name: the name of the property
 * @opaque: the object property opaque
 * @errp: a pointer to an Error that is filled if getting/setting fails.
 *
 * Called when trying to get/set a property.
 */
typedef void (ObjectPropertyAccessor)(Object *obj,
                                      Visitor *v,
                                      const char *name,
                                      void *opaque,
                                      Error **errp);

/**
 * ObjectPropertyResolve:
 * @obj: the object that owns the property
 * @opaque: the opaque registered with the property
 * @part: the name of the property
 *
 * Resolves the #Object corresponding to property @part.
 *
 * The returned object can also be used as a starting point
 * to resolve a relative path starting with "@part".
 *
 * Returns: If @path is the path that led to @obj, the function
 * returns the #Object corresponding to "@path/@part".
 * If "@path/@part" is not a valid object path, it returns #NULL.
 */
typedef Object *(ObjectPropertyResolve)(Object *obj,
                                        void *opaque,
                                        const char *part);

/**
 * ObjectPropertyRelease:
 * @obj: the object that owns the property
 * @name: the name of the property
 * @opaque: the opaque registered with the property
 *
 * Called when a property is removed from a object.
 */
typedef void (ObjectPropertyRelease)(Object *obj,
                                     const char *name,
                                     void *opaque);

/**
 * ObjectPropertyInit:
 * @obj: the object that owns the property
 * @prop: the property to set
 *
 * Called when a property is initialized.
 */
typedef void (ObjectPropertyInit)(Object *obj, ObjectProperty *prop);

struct ObjectProperty
{
    char *name;
    char *type;
    char *description;
    ObjectPropertyAccessor *get;
    ObjectPropertyAccessor *set;
    ObjectPropertyResolve *resolve;
    ObjectPropertyRelease *release;
    ObjectPropertyInit *init;
    void *opaque;
    QObject *defval;
};

/**
 * ObjectUnparent:
 * @obj: the object that is being removed from the composition tree
 *
 * Called when an object is being removed from the QOM composition tree.
 * The function should remove any backlinks from children objects to @obj.
 */
typedef void (ObjectUnparent)(Object *obj);

/**
 * ObjectFree:
 * @obj: the object being freed
 *
 * Called when an object's last reference is removed.
 */
typedef void (ObjectFree)(void *obj);

#define OBJECT_CLASS_CAST_CACHE 4

/**
 * ObjectClass:
 *
 * The base for all classes.  The only thing that #ObjectClass contains is an
 * integer type handle.
 */
struct ObjectClass
{
    /* private: */
    Type type;
    GSList *interfaces;

    const char *object_cast_cache[OBJECT_CLASS_CAST_CACHE];
    const char *class_cast_cache[OBJECT_CLASS_CAST_CACHE];

    ObjectUnparent *unparent;

    GHashTable *properties;
};

/**
 * Object:
 *
 * The base for all objects.  The first member of this object is a pointer to
 * a #ObjectClass.  Since C guarantees that the first member of a structure
 * always begins at byte 0 of that structure, as long as any sub-object places
 * its parent as the first member, we can cast directly to a #Object.
 *
 * As a result, #Object contains a reference to the objects type as its
 * first member.  This allows identification of the real type of the object at
 * run time.
 */
struct Object
{
    /* private: */
    ObjectClass *class;
    ObjectFree *free;
    GHashTable *properties;
    uint32_t ref;
    Object *parent;
};

/**
 * DECLARE_INSTANCE_CHECKER:
 * @InstanceType: instance struct name
 * @OBJ_NAME: the object name in uppercase with underscore separators
 * @TYPENAME: type name
 *
 * Direct usage of this macro should be avoided, and the complete
 * OBJECT_DECLARE_TYPE macro is recommended instead.
 *
 * This macro will provide the three standard type cast functions for a
 * QOM type.
 */
#define DECLARE_INSTANCE_CHECKER(InstanceType, OBJ_NAME, TYPENAME) \
    static inline G_GNUC_UNUSED InstanceType * \
    OBJ_NAME(const void *obj) \
    { return OBJECT_CHECK(InstanceType, obj, TYPENAME); }

/**
 * DECLARE_CLASS_CHECKERS:
 * @ClassType: class struct name
 * @OBJ_NAME: the object name in uppercase with underscore separators
 * @TYPENAME: type name
 *
 * Direct usage of this macro should be avoided, and the complete
 * OBJECT_DECLARE_TYPE macro is recommended instead.
 *
 * This macro will provide the three standard type cast functions for a
 * QOM type.
 */
#define DECLARE_CLASS_CHECKERS(ClassType, OBJ_NAME, TYPENAME) \
    static inline G_GNUC_UNUSED ClassType * \
    OBJ_NAME##_GET_CLASS(const void *obj) \
    { return OBJECT_GET_CLASS(ClassType, obj, TYPENAME); } \
    \
    static inline G_GNUC_UNUSED ClassType * \
    OBJ_NAME##_CLASS(const void *klass) \
    { return OBJECT_CLASS_CHECK(ClassType, klass, TYPENAME); }

/**
 * DECLARE_OBJ_CHECKERS:
 * @InstanceType: instance struct name
 * @ClassType: class struct name
 * @OBJ_NAME: the object name in uppercase with underscore separators
 * @TYPENAME: type name
 *
 * Direct usage of this macro should be avoided, and the complete
 * OBJECT_DECLARE_TYPE macro is recommended instead.
 *
 * This macro will provide the three standard type cast functions for a
 * QOM type.
 */
#define DECLARE_OBJ_CHECKERS(InstanceType, ClassType, OBJ_NAME, TYPENAME) \
    DECLARE_INSTANCE_CHECKER(InstanceType, OBJ_NAME, TYPENAME) \
    \
    DECLARE_CLASS_CHECKERS(ClassType, OBJ_NAME, TYPENAME)

/**
 * OBJECT_DECLARE_TYPE:
 * @InstanceType: instance struct name
 * @ClassType: class struct name
 * @MODULE_OBJ_NAME: the object name in uppercase with underscore separators
 *
 * This macro is typically used in a header file, and will:
 *
 *   - create the typedefs for the object and class structs
 *   - register the type for use with g_autoptr
 *   - provide three standard type cast functions
 *
 * The object struct and class struct need to be declared manually.
 */
#define OBJECT_DECLARE_TYPE(InstanceType, ClassType, MODULE_OBJ_NAME) \
    typedef struct InstanceType InstanceType; \
    typedef struct ClassType ClassType; \
    \
    G_DEFINE_AUTOPTR_CLEANUP_FUNC(InstanceType, object_unref) \
    \
    DECLARE_OBJ_CHECKERS(InstanceType, ClassType, \
                         MODULE_OBJ_NAME, TYPE_##MODULE_OBJ_NAME)

/**
 * OBJECT_DECLARE_SIMPLE_TYPE:
 * @InstanceType: instance struct name
 * @MODULE_OBJ_NAME: the object name in uppercase with underscore separators
 *
 * This does the same as OBJECT_DECLARE_TYPE(), but with no class struct
 * declared.
 *
 * This macro should be used unless the class struct needs to have
 * virtual methods declared.
 */
#define OBJECT_DECLARE_SIMPLE_TYPE(InstanceType, MODULE_OBJ_NAME) \
    typedef struct InstanceType InstanceType; \
    \
    G_DEFINE_AUTOPTR_CLEANUP_FUNC(InstanceType, object_unref) \
    \
    DECLARE_INSTANCE_CHECKER(InstanceType, MODULE_OBJ_NAME, TYPE_##MODULE_OBJ_NAME)


/**
 * OBJECT_DEFINE_TYPE_EXTENDED:
 * @ModuleObjName: the object name with initial caps
 * @module_obj_name: the object name in lowercase with underscore separators
 * @MODULE_OBJ_NAME: the object name in uppercase with underscore separators
 * @PARENT_MODULE_OBJ_NAME: the parent object name in uppercase with underscore
 *                          separators
 * @ABSTRACT: boolean flag to indicate whether the object can be instantiated
 * @...: list of initializers for "InterfaceInfo" to declare implemented interfaces
 *
 * This macro is typically used in a source file, and will:
 *
 *   - declare prototypes for _finalize, _class_init and _init methods
 *   - declare the TypeInfo struct instance
 *   - provide the constructor to register the type
 *
 * After using this macro, implementations of the _finalize, _class_init,
 * and _init methods need to be written. Any of these can be zero-line
 * no-op impls if no special logic is required for a given type.
 *
 * This macro should rarely be used, instead one of the more specialized
 * macros is usually a better choice.
 */
#define OBJECT_DEFINE_TYPE_EXTENDED(ModuleObjName, module_obj_name, \
                                    MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME, \
                                    ABSTRACT, ...) \
    static void \
    module_obj_name##_finalize(Object *obj); \
    static void \
    module_obj_name##_class_init(ObjectClass *oc, void *data); \
    static void \
    module_obj_name##_init(Object *obj); \
    \
    static const TypeInfo module_obj_name##_info = { \
        .parent = TYPE_##PARENT_MODULE_OBJ_NAME, \
        .name = TYPE_##MODULE_OBJ_NAME, \
        .instance_size = sizeof(ModuleObjName), \
        .instance_align = __alignof__(ModuleObjName), \
        .instance_init = module_obj_name##_init, \
        .instance_finalize = module_obj_name##_finalize, \
        .class_size = sizeof(ModuleObjName##Class), \
        .class_init = module_obj_name##_class_init, \
        .abstract = ABSTRACT, \
        .interfaces = (InterfaceInfo[]) { __VA_ARGS__ } , \
    }; \
    \
    static void \
    module_obj_name##_register_types(void) \
    { \
        type_register_static(&module_obj_name##_info); \
    } \
    type_init(module_obj_name##_register_types);

/**
 * OBJECT_DEFINE_TYPE:
 * @ModuleObjName: the object name with initial caps
 * @module_obj_name: the object name in lowercase with underscore separators
 * @MODULE_OBJ_NAME: the object name in uppercase with underscore separators
 * @PARENT_MODULE_OBJ_NAME: the parent object name in uppercase with underscore
 *                          separators
 *
 * This is a specialization of OBJECT_DEFINE_TYPE_EXTENDED, which is suitable
 * for the common case of a non-abstract type, without any interfaces.
 */
#define OBJECT_DEFINE_TYPE(ModuleObjName, module_obj_name, MODULE_OBJ_NAME, \
                           PARENT_MODULE_OBJ_NAME) \
    OBJECT_DEFINE_TYPE_EXTENDED(ModuleObjName, module_obj_name, \
                                MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME, \
                                false, { NULL })

/**
 * OBJECT_DEFINE_TYPE_WITH_INTERFACES:
 * @ModuleObjName: the object name with initial caps
 * @module_obj_name: the object name in lowercase with underscore separators
 * @MODULE_OBJ_NAME: the object name in uppercase with underscore separators
 * @PARENT_MODULE_OBJ_NAME: the parent object name in uppercase with underscore
 *                          separators
 * @...: list of initializers for "InterfaceInfo" to declare implemented interfaces
 *
 * This is a specialization of OBJECT_DEFINE_TYPE_EXTENDED, which is suitable
 * for the common case of a non-abstract type, with one or more implemented
 * interfaces.
 *
 * Note when passing the list of interfaces, be sure to include the final
 * NULL entry, e.g.  { TYPE_USER_CREATABLE }, { NULL }
 */
#define OBJECT_DEFINE_TYPE_WITH_INTERFACES(ModuleObjName, module_obj_name, \
                                           MODULE_OBJ_NAME, \
                                           PARENT_MODULE_OBJ_NAME, ...) \
    OBJECT_DEFINE_TYPE_EXTENDED(ModuleObjName, module_obj_name, \
                                MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME, \
                                false, __VA_ARGS__)

/**
 * OBJECT_DEFINE_ABSTRACT_TYPE:
 * @ModuleObjName: the object name with initial caps
 * @module_obj_name: the object name in lowercase with underscore separators
 * @MODULE_OBJ_NAME: the object name in uppercase with underscore separators
 * @PARENT_MODULE_OBJ_NAME: the parent object name in uppercase with underscore
 *                          separators
 *
 * This is a specialization of OBJECT_DEFINE_TYPE_EXTENDED, which is suitable
 * for defining an abstract type, without any interfaces.
 */
#define OBJECT_DEFINE_ABSTRACT_TYPE(ModuleObjName, module_obj_name, \
                                    MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME) \
    OBJECT_DEFINE_TYPE_EXTENDED(ModuleObjName, module_obj_name, \
                                MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME, \
                                true, { NULL })

/**
 * TypeInfo:
 * @name: The name of the type.
 * @parent: The name of the parent type.
 * @instance_size: The size of the object (derivative of #Object).  If
 *   @instance_size is 0, then the size of the object will be the size of the
 *   parent object.
 * @instance_align: The required alignment of the object.  If @instance_align
 *   is 0, then normal malloc alignment is sufficient; if non-zero, then we
 *   must use qemu_memalign for allocation.
 * @instance_init: This function is called to initialize an object.  The parent
 *   class will have already been initialized so the type is only responsible
 *   for initializing its own members.
 * @instance_post_init: This function is called to finish initialization of
 *   an object, after all @instance_init functions were called.
 * @instance_finalize: This function is called during object destruction.  This
 *   is called before the parent @instance_finalize function has been called.
 *   An object should only free the members that are unique to its type in this
 *   function.
 * @abstract: If this field is true, then the class is considered abstract and
 *   cannot be directly instantiated.
 * @class_size: The size of the class object (derivative of #ObjectClass)
 *   for this object.  If @class_size is 0, then the size of the class will be
 *   assumed to be the size of the parent class.  This allows a type to avoid
 *   implementing an explicit class type if they are not adding additional
 *   virtual functions.
 * @class_init: This function is called after all parent class initialization
 *   has occurred to allow a class to set its default virtual method pointers.
 *   This is also the function to use to override virtual methods from a parent
 *   class.
 * @class_base_init: This function is called for all base classes after all
 *   parent class initialization has occurred, but before the class itself
 *   is initialized.  This is the function to use to undo the effects of
 *   memcpy from the parent class to the descendants.
 * @class_data: Data to pass to the @class_init,
 *   @class_base_init. This can be useful when building dynamic
 *   classes.
 * @interfaces: The list of interfaces associated with this type.  This
 *   should point to a static array that's terminated with a zero filled
 *   element.
 */
struct TypeInfo
{
    const char *name;
    const char *parent;

    size_t instance_size;
    size_t instance_align;
    void (*instance_init)(Object *obj);
    void (*instance_post_init)(Object *obj);
    void (*instance_finalize)(Object *obj);

    bool abstract;
    size_t class_size;

    void (*class_init)(ObjectClass *klass, void *data);
    void (*class_base_init)(ObjectClass *klass, void *data);
    void *class_data;

    InterfaceInfo *interfaces;
};

/**
 * OBJECT:
 * @obj: A derivative of #Object
 *
 * Converts an object to a #Object.  Since all objects are #Objects,
 * this function will always succeed.
 */
#define OBJECT(obj) \
    ((Object *)(obj))

/**
 * OBJECT_CLASS:
 * @class: A derivative of #ObjectClass.
 *
 * Converts a class to an #ObjectClass.  Since all objects are #Objects,
 * this function will always succeed.
 */
#define OBJECT_CLASS(class) \
    ((ObjectClass *)(class))

/**
 * OBJECT_CHECK:
 * @type: The C type to use for the return value.
 * @obj: A derivative of @type to cast.
 * @name: The QOM typename of @type
 *
 * A type safe version of @object_dynamic_cast_assert.  Typically each class
 * will define a macro based on this type to perform type safe dynamic_casts to
 * this object type.
 *
 * If an invalid object is passed to this function, a run time assert will be
 * generated.
 */
#define OBJECT_CHECK(type, obj, name) \
    ((type *)object_dynamic_cast_assert(OBJECT(obj), (name), \
                                        __FILE__, __LINE__, __func__))

/**
 * OBJECT_CLASS_CHECK:
 * @class_type: The C type to use for the return value.
 * @class: A derivative class of @class_type to cast.
 * @name: the QOM typename of @class_type.
 *
 * A type safe version of @object_class_dynamic_cast_assert.  This macro is
 * typically wrapped by each type to perform type safe casts of a class to a
 * specific class type.
 */
#define OBJECT_CLASS_CHECK(class_type, class, name) \
    ((class_type *)object_class_dynamic_cast_assert(OBJECT_CLASS(class), (name), \
                                               __FILE__, __LINE__, __func__))

/**
 * OBJECT_GET_CLASS:
 * @class: The C type to use for the return value.
 * @obj: The object to obtain the class for.
 * @name: The QOM typename of @obj.
 *
 * This function will return a specific class for a given object.  Its generally
 * used by each type to provide a type safe macro to get a specific class type
 * from an object.
 */
#define OBJECT_GET_CLASS(class, obj, name) \
    OBJECT_CLASS_CHECK(class, object_get_class(OBJECT(obj)), name)

/**
 * InterfaceInfo:
 * @type: The name of the interface.
 *
 * The information associated with an interface.
 */
struct InterfaceInfo {
    const char *type;
};

/**
 * InterfaceClass:
 * @parent_class: the base class
 *
 * The class for all interfaces.  Subclasses of this class should only add
 * virtual methods.
 */
struct InterfaceClass
{
    ObjectClass parent_class;
    /* private: */
    ObjectClass *concrete_class;
    Type interface_type;
};

#define TYPE_INTERFACE "interface"

/**
 * INTERFACE_CLASS:
 * @klass: class to cast from
 * Returns: An #InterfaceClass or raise an error if cast is invalid
 */
#define INTERFACE_CLASS(klass) \
    OBJECT_CLASS_CHECK(InterfaceClass, klass, TYPE_INTERFACE)

/**
 * INTERFACE_CHECK:
 * @interface: the type to return
 * @obj: the object to convert to an interface
 * @name: the interface type name
 *
 * Returns: @obj casted to @interface if cast is valid, otherwise raise error.
 */
#define INTERFACE_CHECK(interface, obj, name) \
    ((interface *)object_dynamic_cast_assert(OBJECT((obj)), (name), \
                                             __FILE__, __LINE__, __func__))

/**
 * object_new_with_class:
 * @klass: The class to instantiate.
 *
 * This function will initialize a new object using heap allocated memory.
 * The returned object has a reference count of 1, and will be freed when
 * the last reference is dropped.
 *
 * Returns: The newly allocated and instantiated object.
 */
Object *object_new_with_class(ObjectClass *klass);

/**
 * object_new:
 * @typename: The name of the type of the object to instantiate.
 *
 * This function will initialize a new object using heap allocated memory.
 * The returned object has a reference count of 1, and will be freed when
 * the last reference is dropped.
 *
 * Returns: The newly allocated and instantiated object.
 */
Object *object_new(const char *typename);

/**
 * object_new_with_props:
 * @typename:  The name of the type of the object to instantiate.
 * @parent: the parent object
 * @id: The unique ID of the object
 * @errp: pointer to error object
 * @...: list of property names and values
 *
 * This function will initialize a new object using heap allocated memory.
 * The returned object has a reference count of 1, and will be freed when
 * the last reference is dropped.
 *
 * The @id parameter will be used when registering the object as a
 * child of @parent in the composition tree.
 *
 * The variadic parameters are a list of pairs of (propname, propvalue)
 * strings. The propname of %NULL indicates the end of the property
 * list. If the object implements the user creatable interface, the
 * object will be marked complete once all the properties have been
 * processed.
 *
 * <example>
 *   <title>Creating an object with properties</title>
 *      <programlisting>
 *      Error *err = NULL;
 *      Object *obj;
 *
 *      obj = object_new_with_props(TYPE_MEMORY_BACKEND_FILE,
 *                                  object_get_objects_root(),
 *                                  "hostmem0",
 *                                  &err,
 *                                  "share", "yes",
 *                                  "mem-path", "/dev/shm/somefile",
 *                                  "prealloc", "yes",
 *                                  "size", "1048576",
 *                                  NULL);
 *
 *      if (!obj) {
 *        error_reportf_err(err, "Cannot create memory backend: ");
 *      }
 *      </programlisting>
 * </example>
 *
 * The returned object will have one stable reference maintained
 * for as long as it is present in the object hierarchy.
 *
 * Returns: The newly allocated, instantiated & initialized object.
 */
Object *object_new_with_props(const char *typename,
                              Object *parent,
                              const char *id,
                              Error **errp,
                              ...) QEMU_SENTINEL;

/**
 * object_new_with_propv:
 * @typename:  The name of the type of the object to instantiate.
 * @parent: the parent object
 * @id: The unique ID of the object
 * @errp: pointer to error object
 * @vargs: list of property names and values
 *
 * See object_new_with_props() for documentation.
 */
Object *object_new_with_propv(const char *typename,
                              Object *parent,
                              const char *id,
                              Error **errp,
                              va_list vargs);

bool object_apply_global_props(Object *obj, const GPtrArray *props,
                               Error **errp);
void object_set_machine_compat_props(GPtrArray *compat_props);
void object_set_accelerator_compat_props(GPtrArray *compat_props);
void object_register_sugar_prop(const char *driver, const char *prop, const char *value);
void object_apply_compat_props(Object *obj);

/**
 * object_set_props:
 * @obj: the object instance to set properties on
 * @errp: pointer to error object
 * @...: list of property names and values
 *
 * This function will set a list of properties on an existing object
 * instance.
 *
 * The variadic parameters are a list of pairs of (propname, propvalue)
 * strings. The propname of %NULL indicates the end of the property
 * list.
 *
 * <example>
 *   <title>Update an object's properties</title>
 *      <programlisting>
 *      Error *err = NULL;
 *      Object *obj = ...get / create object...;
 *
 *      if (!object_set_props(obj,
 *                            &err,
 *                            "share", "yes",
 *                            "mem-path", "/dev/shm/somefile",
 *                            "prealloc", "yes",
 *                            "size", "1048576",
 *                            NULL)) {
 *        error_reportf_err(err, "Cannot set properties: ");
 *      }
 *      </programlisting>
 * </example>
 *
 * The returned object will have one stable reference maintained
 * for as long as it is present in the object hierarchy.
 *
 * Returns: %true on success, %false on error.
 */
bool object_set_props(Object *obj, Error **errp, ...) QEMU_SENTINEL;

/**
 * object_set_propv:
 * @obj: the object instance to set properties on
 * @errp: pointer to error object
 * @vargs: list of property names and values
 *
 * See object_set_props() for documentation.
 *
 * Returns: %true on success, %false on error.
 */
bool object_set_propv(Object *obj, Error **errp, va_list vargs);

/**
 * object_initialize:
 * @obj: A pointer to the memory to be used for the object.
 * @size: The maximum size available at @obj for the object.
 * @typename: The name of the type of the object to instantiate.
 *
 * This function will initialize an object.  The memory for the object should
 * have already been allocated.  The returned object has a reference count of 1,
 * and will be finalized when the last reference is dropped.
 */
void object_initialize(void *obj, size_t size, const char *typename);

/**
 * object_initialize_child_with_props:
 * @parentobj: The parent object to add a property to
 * @propname: The name of the property
 * @childobj: A pointer to the memory to be used for the object.
 * @size: The maximum size available at @childobj for the object.
 * @type: The name of the type of the object to instantiate.
 * @errp: If an error occurs, a pointer to an area to store the error
 * @...: list of property names and values
 *
 * This function will initialize an object. The memory for the object should
 * have already been allocated. The object will then be added as child property
 * to a parent with object_property_add_child() function. The returned object
 * has a reference count of 1 (for the "child<...>" property from the parent),
 * so the object will be finalized automatically when the parent gets removed.
 *
 * The variadic parameters are a list of pairs of (propname, propvalue)
 * strings. The propname of %NULL indicates the end of the property list.
 * If the object implements the user creatable interface, the object will
 * be marked complete once all the properties have been processed.
 *
 * Returns: %true on success, %false on failure.
 */
bool object_initialize_child_with_props(Object *parentobj,
                             const char *propname,
                             void *childobj, size_t size, const char *type,
                             Error **errp, ...) QEMU_SENTINEL;

/**
 * object_initialize_child_with_propsv:
 * @parentobj: The parent object to add a property to
 * @propname: The name of the property
 * @childobj: A pointer to the memory to be used for the object.
 * @size: The maximum size available at @childobj for the object.
 * @type: The name of the type of the object to instantiate.
 * @errp: If an error occurs, a pointer to an area to store the error
 * @vargs: list of property names and values
 *
 * See object_initialize_child() for documentation.
 *
 * Returns: %true on success, %false on failure.
 */
bool object_initialize_child_with_propsv(Object *parentobj,
                              const char *propname,
                              void *childobj, size_t size, const char *type,
                              Error **errp, va_list vargs);

/**
 * object_initialize_child:
 * @parent: The parent object to add a property to
 * @propname: The name of the property
 * @child: A precisely typed pointer to the memory to be used for the
 * object.
 * @type: The name of the type of the object to instantiate.
 *
 * This is like
 * object_initialize_child_with_props(parent, propname,
 *                                    child, sizeof(*child), type,
 *                                    &error_abort, NULL)
 */
#define object_initialize_child(parent, propname, child, type)          \
    object_initialize_child_internal((parent), (propname),              \
                                     (child), sizeof(*(child)), (type))
void object_initialize_child_internal(Object *parent, const char *propname,
                                      void *child, size_t size,
                                      const char *type);

/**
 * object_dynamic_cast:
 * @obj: The object to cast.
 * @typename: The @typename to cast to.
 *
 * This function will determine if @obj is-a @typename.  @obj can refer to an
 * object or an interface associated with an object.
 *
 * Returns: This function returns @obj on success or #NULL on failure.
 */
Object *object_dynamic_cast(Object *obj, const char *typename);

/**
 * object_dynamic_cast_assert:
 * @obj: The object to cast.
 * @typename: The @typename to cast to.
 * @file: Source code file where function was called
 * @line: Source code line where function was called
 * @func: Name of function where this function was called
 *
 * See object_dynamic_cast() for a description of the parameters of this
 * function.  The only difference in behavior is that this function asserts
 * instead of returning #NULL on failure if QOM cast debugging is enabled.
 * This function is not meant to be called directly, but only through
 * the wrapper macro OBJECT_CHECK.
 */
Object *object_dynamic_cast_assert(Object *obj, const char *typename,
                                   const char *file, int line, const char *func);

/**
 * object_get_class:
 * @obj: A derivative of #Object
 *
 * Returns: The #ObjectClass of the type associated with @obj.
 */
ObjectClass *object_get_class(Object *obj);

/**
 * object_get_typename:
 * @obj: A derivative of #Object.
 *
 * Returns: The QOM typename of @obj.
 */
const char *object_get_typename(const Object *obj);

/**
 * type_register_static:
 * @info: The #TypeInfo of the new type.
 *
 * @info and all of the strings it points to should exist for the life time
 * that the type is registered.
 *
 * Returns: the new #Type.
 */
Type type_register_static(const TypeInfo *info);

/**
 * type_register:
 * @info: The #TypeInfo of the new type
 *
 * Unlike type_register_static(), this call does not require @info or its
 * string members to continue to exist after the call returns.
 *
 * Returns: the new #Type.
 */
Type type_register(const TypeInfo *info);

/**
 * type_register_static_array:
 * @infos: The array of the new type #TypeInfo structures.
 * @nr_infos: number of entries in @infos
 *
 * @infos and all of the strings it points to should exist for the life time
 * that the type is registered.
 */
void type_register_static_array(const TypeInfo *infos, int nr_infos);

/**
 * DEFINE_TYPES:
 * @type_array: The array containing #TypeInfo structures to register
 *
 * @type_array should be static constant that exists for the life time
 * that the type is registered.
 */
#define DEFINE_TYPES(type_array)                                            \
static void do_qemu_init_ ## type_array(void)                               \
{                                                                           \
    type_register_static_array(type_array, ARRAY_SIZE(type_array));         \
}                                                                           \
type_init(do_qemu_init_ ## type_array)

/**
 * object_class_dynamic_cast_assert:
 * @klass: The #ObjectClass to attempt to cast.
 * @typename: The QOM typename of the class to cast to.
 * @file: Source code file where function was called
 * @line: Source code line where function was called
 * @func: Name of function where this function was called
 *
 * See object_class_dynamic_cast() for a description of the parameters
 * of this function.  The only difference in behavior is that this function
 * asserts instead of returning #NULL on failure if QOM cast debugging is
 * enabled.  This function is not meant to be called directly, but only through
 * the wrapper macro OBJECT_CLASS_CHECK.
 */
ObjectClass *object_class_dynamic_cast_assert(ObjectClass *klass,
                                              const char *typename,
                                              const char *file, int line,
                                              const char *func);

/**
 * object_class_dynamic_cast:
 * @klass: The #ObjectClass to attempt to cast.
 * @typename: The QOM typename of the class to cast to.
 *
 * Returns: If @typename is a class, this function returns @klass if
 * @typename is a subtype of @klass, else returns #NULL.
 *
 * If @typename is an interface, this function returns the interface
 * definition for @klass if @klass implements it unambiguously; #NULL
 * is returned if @klass does not implement the interface or if multiple
 * classes or interfaces on the hierarchy leading to @klass implement
 * it.  (FIXME: perhaps this can be detected at type definition time?)
 */
ObjectClass *object_class_dynamic_cast(ObjectClass *klass,
                                       const char *typename);

/**
 * object_class_get_parent:
 * @klass: The class to obtain the parent for.
 *
 * Returns: The parent for @klass or %NULL if none.
 */
ObjectClass *object_class_get_parent(ObjectClass *klass);

/**
 * object_class_get_name:
 * @klass: The class to obtain the QOM typename for.
 *
 * Returns: The QOM typename for @klass.
 */
const char *object_class_get_name(ObjectClass *klass);

/**
 * object_class_is_abstract:
 * @klass: The class to obtain the abstractness for.
 *
 * Returns: %true if @klass is abstract, %false otherwise.
 */
bool object_class_is_abstract(ObjectClass *klass);

/**
 * object_class_by_name:
 * @typename: The QOM typename to obtain the class for.
 *
 * Returns: The class for @typename or %NULL if not found.
 */
ObjectClass *object_class_by_name(const char *typename);

/**
 * module_object_class_by_name:
 * @typename: The QOM typename to obtain the class for.
 *
 * For objects which might be provided by a module.  Behaves like
 * object_class_by_name, but additionally tries to load the module
 * needed in case the class is not available.
 *
 * Returns: The class for @typename or %NULL if not found.
 */
ObjectClass *module_object_class_by_name(const char *typename);

void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
                          const char *implements_type, bool include_abstract,
                          void *opaque);

/**
 * object_class_get_list:
 * @implements_type: The type to filter for, including its derivatives.
 * @include_abstract: Whether to include abstract classes.
 *
 * Returns: A singly-linked list of the classes in reverse hashtable order.
 */
GSList *object_class_get_list(const char *implements_type,
                              bool include_abstract);

/**
 * object_class_get_list_sorted:
 * @implements_type: The type to filter for, including its derivatives.
 * @include_abstract: Whether to include abstract classes.
 *
 * Returns: A singly-linked list of the classes in alphabetical
 * case-insensitive order.
 */
GSList *object_class_get_list_sorted(const char *implements_type,
                              bool include_abstract);

/**
 * object_ref:
 * @obj: the object
 *
 * Increase the reference count of a object.  A object cannot be freed as long
 * as its reference count is greater than zero.
 * Returns: @obj
 */
Object *object_ref(void *obj);

/**
 * object_unref:
 * @obj: the object
 *
 * Decrease the reference count of a object.  A object cannot be freed as long
 * as its reference count is greater than zero.
 */
void object_unref(void *obj);

/**
 * object_property_try_add:
 * @obj: the object to add a property to
 * @name: the name of the property.  This can contain any character except for
 *  a forward slash.  In general, you should use hyphens '-' instead of
 *  underscores '_' when naming properties.
 * @type: the type name of the property.  This namespace is pretty loosely
 *   defined.  Sub namespaces are constructed by using a prefix and then
 *   to angle brackets.  For instance, the type 'virtio-net-pci' in the
 *   'link' namespace would be 'link<virtio-net-pci>'.
 * @get: The getter to be called to read a property.  If this is NULL, then
 *   the property cannot be read.
 * @set: the setter to be called to write a property.  If this is NULL,
 *   then the property cannot be written.
 * @release: called when the property is removed from the object.  This is
 *   meant to allow a property to free its opaque upon object
 *   destruction.  This may be NULL.
 * @opaque: an opaque pointer to pass to the callbacks for the property
 * @errp: pointer to error object
 *
 * Returns: The #ObjectProperty; this can be used to set the @resolve
 * callback for child and link properties.
 */
ObjectProperty *object_property_try_add(Object *obj, const char *name,
                                        const char *type,
                                        ObjectPropertyAccessor *get,
                                        ObjectPropertyAccessor *set,
                                        ObjectPropertyRelease *release,
                                        void *opaque, Error **errp);

/**
 * object_property_add:
 * Same as object_property_try_add() with @errp hardcoded to
 * &error_abort.
 *
 * @obj: the object to add a property to
 * @name: the name of the property.  This can contain any character except for
 *  a forward slash.  In general, you should use hyphens '-' instead of
 *  underscores '_' when naming properties.
 * @type: the type name of the property.  This namespace is pretty loosely
 *   defined.  Sub namespaces are constructed by using a prefix and then
 *   to angle brackets.  For instance, the type 'virtio-net-pci' in the
 *   'link' namespace would be 'link<virtio-net-pci>'.
 * @get: The getter to be called to read a property.  If this is NULL, then
 *   the property cannot be read.
 * @set: the setter to be called to write a property.  If this is NULL,
 *   then the property cannot be written.
 * @release: called when the property is removed from the object.  This is
 *   meant to allow a property to free its opaque upon object
 *   destruction.  This may be NULL.
 * @opaque: an opaque pointer to pass to the callbacks for the property
 */
ObjectProperty *object_property_add(Object *obj, const char *name,
                                    const char *type,
                                    ObjectPropertyAccessor *get,
                                    ObjectPropertyAccessor *set,
                                    ObjectPropertyRelease *release,
                                    void *opaque);

void object_property_del(Object *obj, const char *name);

ObjectProperty *object_class_property_add(ObjectClass *klass, const char *name,
                                          const char *type,
                                          ObjectPropertyAccessor *get,
                                          ObjectPropertyAccessor *set,
                                          ObjectPropertyRelease *release,
                                          void *opaque);

/**
 * object_property_set_default_bool:
 * @prop: the property to set
 * @value: the value to be written to the property
 *
 * Set the property default value.
 */
void object_property_set_default_bool(ObjectProperty *prop, bool value);

/**
 * object_property_set_default_str:
 * @prop: the property to set
 * @value: the value to be written to the property
 *
 * Set the property default value.
 */
void object_property_set_default_str(ObjectProperty *prop, const char *value);

/**
 * object_property_set_default_int:
 * @prop: the property to set
 * @value: the value to be written to the property
 *
 * Set the property default value.
 */
void object_property_set_default_int(ObjectProperty *prop, int64_t value);

/**
 * object_property_set_default_uint:
 * @prop: the property to set
 * @value: the value to be written to the property
 *
 * Set the property default value.
 */
void object_property_set_default_uint(ObjectProperty *prop, uint64_t value);

/**
 * object_property_find:
 * @obj: the object
 * @name: the name of the property
 *
 * Look up a property for an object.
 *
 * Return its #ObjectProperty if found, or NULL.
 */
ObjectProperty *object_property_find(Object *obj, const char *name);

/**
 * object_property_find_err:
 * @obj: the object
 * @name: the name of the property
 * @errp: returns an error if this function fails
 *
 * Look up a property for an object.
 *
 * Return its #ObjectProperty if found, or NULL.
 */
ObjectProperty *object_property_find_err(Object *obj,
                                         const char *name,
                                         Error **errp);

/**
 * object_class_property_find:
 * @klass: the object class
 * @name: the name of the property
 *
 * Look up a property for an object class.
 *
 * Return its #ObjectProperty if found, or NULL.
 */
ObjectProperty *object_class_property_find(ObjectClass *klass,
                                           const char *name);

/**
 * object_class_property_find_err:
 * @klass: the object class
 * @name: the name of the property
 * @errp: returns an error if this function fails
 *
 * Look up a property for an object class.
 *
 * Return its #ObjectProperty if found, or NULL.
 */
ObjectProperty *object_class_property_find_err(ObjectClass *klass,
                                               const char *name,
                                               Error **errp);

typedef struct ObjectPropertyIterator {
    ObjectClass *nextclass;
    GHashTableIter iter;
} ObjectPropertyIterator;

/**
 * object_property_iter_init:
 * @iter: the iterator instance
 * @obj: the object
 *
 * Initializes an iterator for traversing all properties
 * registered against an object instance, its class and all parent classes.
 *
 * It is forbidden to modify the property list while iterating,
 * whether removing or adding properties.
 *
 * Typical usage pattern would be
 *
 * <example>
 *   <title>Using object property iterators</title>
 *      <programlisting>
 *      ObjectProperty *prop;
 *      ObjectPropertyIterator iter;
 *
 *      object_property_iter_init(&iter, obj);
 *      while ((prop = object_property_iter_next(&iter))) {
 *        ... do something with prop ...
 *      }
 *      </programlisting>
 * </example>
 */
void object_property_iter_init(ObjectPropertyIterator *iter,
                               Object *obj);

/**
 * object_class_property_iter_init:
 * @iter: the iterator instance
 * @klass: the class
 *
 * Initializes an iterator for traversing all properties
 * registered against an object class and all parent classes.
 *
 * It is forbidden to modify the property list while iterating,
 * whether removing or adding properties.
 *
 * This can be used on abstract classes as it does not create a temporary
 * instance.
 */
void object_class_property_iter_init(ObjectPropertyIterator *iter,
                                     ObjectClass *klass);

/**
 * object_property_iter_next:
 * @iter: the iterator instance
 *
 * Return the next available property. If no further properties
 * are available, a %NULL value will be returned and the @iter
 * pointer should not be used again after this point without
 * re-initializing it.
 *
 * Returns: the next property, or %NULL when all properties
 * have been traversed.
 */
ObjectProperty *object_property_iter_next(ObjectPropertyIterator *iter);

void object_unparent(Object *obj);

/**
 * object_property_get:
 * @obj: the object
 * @name: the name of the property
 * @v: the visitor that will receive the property value.  This should be an
 *   Output visitor and the data will be written with @name as the name.
 * @errp: returns an error if this function fails
 *
 * Reads a property from a object.
 *
 * Returns: %true on success, %false on failure.
 */
bool object_property_get(Object *obj, const char *name, Visitor *v,
                         Error **errp);

/**
 * object_property_set_str:
 * @obj: the object
 * @name: the name of the property
 * @value: the value to be written to the property
 * @errp: returns an error if this function fails
 *
 * Writes a string value to a property.
 *
 * Returns: %true on success, %false on failure.
 */
bool object_property_set_str(Object *obj, const char *name,
                             const char *value, Error **errp);

/**
 * object_property_get_str:
 * @obj: the object
 * @name: the name of the property
 * @errp: returns an error if this function fails
 *
 * Returns: the value of the property, converted to a C string, or NULL if
 * an error occurs (including when the property value is not a string).
 * The caller should free the string.
 */
char *object_property_get_str(Object *obj, const char *name,
                              Error **errp);

/**
 * object_property_set_link:
 * @obj: the object
 * @name: the name of the property
 * @value: the value to be written to the property
 * @errp: returns an error if this function fails
 *
 * Writes an object's canonical path to a property.
 *
 * If the link property was created with
 * <code>OBJ_PROP_LINK_STRONG</code> bit, the old target object is
 * unreferenced, and a reference is added to the new target object.
 *
 * Returns: %true on success, %false on failure.
 */
bool object_property_set_link(Object *obj, const char *name,
                              Object *value, Error **errp);

/**
 * object_property_get_link:
 * @obj: the object
 * @name: the name of the property
 * @errp: returns an error if this function fails
 *
 * Returns: the value of the property, resolved from a path to an Object,
 * or NULL if an error occurs (including when the property value is not a
 * string or not a valid object path).
 */
Object *object_property_get_link(Object *obj, const char *name,
                                 Error **errp);

/**
 * object_property_set_bool:
 * @obj: the object
 * @name: the name of the property
 * @value: the value to be written to the property
 * @errp: returns an error if this function fails
 *
 * Writes a bool value to a property.
 *
 * Returns: %true on success, %false on failure.
 */
bool object_property_set_bool(Object *obj, const char *name,
                              bool value, Error **errp);

/**
 * object_property_get_bool:
 * @obj: the object
 * @name: the name of the property
 * @errp: returns an error if this function fails
 *
 * Returns: the value of the property, converted to a boolean, or false if
 * an error occurs (including when the property value is not a bool).
 */
bool object_property_get_bool(Object *obj, const char *name,
                              Error **errp);

/**
 * object_property_set_int:
 * @obj: the object
 * @name: the name of the property
 * @value: the value to be written to the property
 * @errp: returns an error if this function fails
 *
 * Writes an integer value to a property.
 *
 * Returns: %true on success, %false on failure.
 */
bool object_property_set_int(Object *obj, const char *name,
                             int64_t value, Error **errp);

/**
 * object_property_get_int:
 * @obj: the object
 * @name: the name of the property
 * @errp: returns an error if this function fails
 *
 * Returns: the value of the property, converted to an integer, or -1 if
 * an error occurs (including when the property value is not an integer).
 */
int64_t object_property_get_int(Object *obj, const char *name,
                                Error **errp);

/**
 * object_property_set_uint:
 * @obj: the object
 * @name: the name of the property
 * @value: the value to be written to the property
 * @errp: returns an error if this function fails
 *
 * Writes an unsigned integer value to a property.
 *
 * Returns: %true on success, %false on failure.
 */
bool object_property_set_uint(Object *obj, const char *name,
                              uint64_t value, Error **errp);

/**
 * object_property_get_uint:
 * @obj: the object
 * @name: the name of the property
 * @errp: returns an error if this function fails
 *
 * Returns: the value of the property, converted to an unsigned integer, or 0
 * an error occurs (including when the property value is not an integer).
 */
uint64_t object_property_get_uint(Object *obj, const char *name,
                                  Error **errp);

/**
 * object_property_get_enum:
 * @obj: the object
 * @name: the name of the property
 * @typename: the name of the enum data type
 * @errp: returns an error if this function fails
 *
 * Returns: the value of the property, converted to an integer (which
 * can't be negative), or -1 on error (including when the property
 * value is not an enum).
 */
int object_property_get_enum(Object *obj, const char *name,
                             const char *typename, Error **errp);

/**
 * object_property_set:
 * @obj: the object
 * @name: the name of the property
 * @v: the visitor that will be used to write the property value.  This should
 *   be an Input visitor and the data will be first read with @name as the
 *   name and then written as the property value.
 * @errp: returns an error if this function fails
 *
 * Writes a property to a object.
 *
 * Returns: %true on success, %false on failure.
 */
bool object_property_set(Object *obj, const char *name, Visitor *v,
                         Error **errp);

/**
 * object_property_parse:
 * @obj: the object
 * @name: the name of the property
 * @string: the string that will be used to parse the property value.
 * @errp: returns an error if this function fails
 *
 * Parses a string and writes the result into a property of an object.
 *
 * Returns: %true on success, %false on failure.
 */
bool object_property_parse(Object *obj, const char *name,
                           const char *string, Error **errp);

/**
 * object_property_print:
 * @obj: the object
 * @name: the name of the property
 * @human: if true, print for human consumption
 * @errp: returns an error if this function fails
 *
 * Returns a string representation of the value of the property.  The
 * caller shall free the string.
 */
char *object_property_print(Object *obj, const char *name, bool human,
                            Error **errp);

/**
 * object_property_get_type:
 * @obj: the object
 * @name: the name of the property
 * @errp: returns an error if this function fails
 *
 * Returns:  The type name of the property.
 */
const char *object_property_get_type(Object *obj, const char *name,
                                     Error **errp);

/**
 * object_get_root:
 *
 * Returns: the root object of the composition tree
 */
Object *object_get_root(void);


/**
 * object_get_objects_root:
 *
 * Get the container object that holds user created
 * object instances. This is the object at path
 * "/objects"
 *
 * Returns: the user object container
 */
Object *object_get_objects_root(void);

/**
 * object_get_internal_root:
 *
 * Get the container object that holds internally used object
 * instances.  Any object which is put into this container must not be
 * user visible, and it will not be exposed in the QOM tree.
 *
 * Returns: the internal object container
 */
Object *object_get_internal_root(void);

/**
 * object_get_canonical_path_component:
 * @obj: the object
 *
 * Returns: The final component in the object's canonical path.  The canonical
 * path is the path within the composition tree starting from the root.
 * %NULL if the object doesn't have a parent (and thus a canonical path).
 */
const char *object_get_canonical_path_component(const Object *obj);

/**
 * object_get_canonical_path:
 * @obj: the object
 *
 * Returns: The canonical path for a object, newly allocated.  This is
 * the path within the composition tree starting from the root.  Use
 * g_free() to free it.
 */
char *object_get_canonical_path(const Object *obj);

/**
 * object_resolve_path:
 * @path: the path to resolve
 * @ambiguous: returns true if the path resolution failed because of an
 *   ambiguous match
 *
 * There are two types of supported paths--absolute paths and partial paths.
 * 
 * Absolute paths are derived from the root object and can follow child<> or
 * link<> properties.  Since they can follow link<> properties, they can be
 * arbitrarily long.  Absolute paths look like absolute filenames and are
 * prefixed with a leading slash.
 * 
 * Partial paths look like relative filenames.  They do not begin with a
 * prefix.  The matching rules for partial paths are subtle but designed to make
 * specifying objects easy.  At each level of the composition tree, the partial
 * path is matched as an absolute path.  The first match is not returned.  At
 * least two matches are searched for.  A successful result is only returned if
 * only one match is found.  If more than one match is found, a flag is
 * returned to indicate that the match was ambiguous.
 *
 * Returns: The matched object or NULL on path lookup failure.
 */
Object *object_resolve_path(const char *path, bool *ambiguous);

/**
 * object_resolve_path_type:
 * @path: the path to resolve
 * @typename: the type to look for.
 * @ambiguous: returns true if the path resolution failed because of an
 *   ambiguous match
 *
 * This is similar to object_resolve_path.  However, when looking for a
 * partial path only matches that implement the given type are considered.
 * This restricts the search and avoids spuriously flagging matches as
 * ambiguous.
 *
 * For both partial and absolute paths, the return value goes through
 * a dynamic cast to @typename.  This is important if either the link,
 * or the typename itself are of interface types.
 *
 * Returns: The matched object or NULL on path lookup failure.
 */
Object *object_resolve_path_type(const char *path, const char *typename,
                                 bool *ambiguous);

/**
 * object_resolve_path_component:
 * @parent: the object in which to resolve the path
 * @part: the component to resolve.
 *
 * This is similar to object_resolve_path with an absolute path, but it
 * only resolves one element (@part) and takes the others from @parent.
 *
 * Returns: The resolved object or NULL on path lookup failure.
 */
Object *object_resolve_path_component(Object *parent, const char *part);

/**
 * object_property_try_add_child:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @child: the child object
 * @errp: pointer to error object
 *
 * Child properties form the composition tree.  All objects need to be a child
 * of another object.  Objects can only be a child of one object.
 *
 * There is no way for a child to determine what its parent is.  It is not
 * a bidirectional relationship.  This is by design.
 *
 * The value of a child property as a C string will be the child object's
 * canonical path. It can be retrieved using object_property_get_str().
 * The child object itself can be retrieved using object_property_get_link().
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_try_add_child(Object *obj, const char *name,
                                              Object *child, Error **errp);

/**
 * object_property_add_child:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @child: the child object
 *
 * Same as object_property_try_add_child() with @errp hardcoded to
 * &error_abort
 */
ObjectProperty *object_property_add_child(Object *obj, const char *name,
                                          Object *child);

typedef enum {
    /* Unref the link pointer when the property is deleted */
    OBJ_PROP_LINK_STRONG = 0x1,

    /* private */
    OBJ_PROP_LINK_DIRECT = 0x2,
    OBJ_PROP_LINK_CLASS = 0x4,
} ObjectPropertyLinkFlags;

/**
 * object_property_allow_set_link:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @child: the child object
 * @errp: pointer to error object
 *
 * The default implementation of the object_property_add_link() check()
 * callback function.  It allows the link property to be set and never returns
 * an error.
 */
void object_property_allow_set_link(const Object *obj, const char *name,
                                    Object *child, Error **errp);

/**
 * object_property_add_link:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @type: the qobj type of the link
 * @targetp: a pointer to where the link object reference is stored
 * @check: callback to veto setting or NULL if the property is read-only
 * @flags: additional options for the link
 *
 * Links establish relationships between objects.  Links are unidirectional
 * although two links can be combined to form a bidirectional relationship
 * between objects.
 *
 * Links form the graph in the object model.
 *
 * The <code>@check()</code> callback is invoked when
 * object_property_set_link() is called and can raise an error to prevent the
 * link being set.  If <code>@check</code> is NULL, the property is read-only
 * and cannot be set.
 *
 * Ownership of the pointer that @child points to is transferred to the
 * link property.  The reference count for <code>*@child</code> is
 * managed by the property from after the function returns till the
 * property is deleted with object_property_del().  If the
 * <code>@flags</code> <code>OBJ_PROP_LINK_STRONG</code> bit is set,
 * the reference count is decremented when the property is deleted or
 * modified.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_link(Object *obj, const char *name,
                              const char *type, Object **targetp,
                              void (*check)(const Object *obj, const char *name,
                                            Object *val, Error **errp),
                              ObjectPropertyLinkFlags flags);

ObjectProperty *object_class_property_add_link(ObjectClass *oc,
                              const char *name,
                              const char *type, ptrdiff_t offset,
                              void (*check)(const Object *obj, const char *name,
                                            Object *val, Error **errp),
                              ObjectPropertyLinkFlags flags);

/**
 * object_property_add_str:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @get: the getter or NULL if the property is write-only.  This function must
 *   return a string to be freed by g_free().
 * @set: the setter or NULL if the property is read-only
 *
 * Add a string property using getters/setters.  This function will add a
 * property of type 'string'.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_str(Object *obj, const char *name,
                             char *(*get)(Object *, Error **),
                             void (*set)(Object *, const char *, Error **));

ObjectProperty *object_class_property_add_str(ObjectClass *klass,
                                   const char *name,
                                   char *(*get)(Object *, Error **),
                                   void (*set)(Object *, const char *,
                                               Error **));

/**
 * object_property_add_bool:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @get: the getter or NULL if the property is write-only.
 * @set: the setter or NULL if the property is read-only
 *
 * Add a bool property using getters/setters.  This function will add a
 * property of type 'bool'.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_bool(Object *obj, const char *name,
                              bool (*get)(Object *, Error **),
                              void (*set)(Object *, bool, Error **));

ObjectProperty *object_class_property_add_bool(ObjectClass *klass,
                                    const char *name,
                                    bool (*get)(Object *, Error **),
                                    void (*set)(Object *, bool, Error **));

/**
 * object_property_add_enum:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @typename: the name of the enum data type
 * @lookup: enum value namelookup table
 * @get: the getter or %NULL if the property is write-only.
 * @set: the setter or %NULL if the property is read-only
 *
 * Add an enum property using getters/setters.  This function will add a
 * property of type '@typename'.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_enum(Object *obj, const char *name,
                              const char *typename,
                              const QEnumLookup *lookup,
                              int (*get)(Object *, Error **),
                              void (*set)(Object *, int, Error **));

ObjectProperty *object_class_property_add_enum(ObjectClass *klass,
                                    const char *name,
                                    const char *typename,
                                    const QEnumLookup *lookup,
                                    int (*get)(Object *, Error **),
                                    void (*set)(Object *, int, Error **));

/**
 * object_property_add_tm:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @get: the getter or NULL if the property is write-only.
 *
 * Add a read-only struct tm valued property using a getter function.
 * This function will add a property of type 'struct tm'.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_tm(Object *obj, const char *name,
                            void (*get)(Object *, struct tm *, Error **));

ObjectProperty *object_class_property_add_tm(ObjectClass *klass,
                            const char *name,
                            void (*get)(Object *, struct tm *, Error **));

typedef enum {
    /* Automatically add a getter to the property */
    OBJ_PROP_FLAG_READ = 1 << 0,
    /* Automatically add a setter to the property */
    OBJ_PROP_FLAG_WRITE = 1 << 1,
    /* Automatically add a getter and a setter to the property */
    OBJ_PROP_FLAG_READWRITE = (OBJ_PROP_FLAG_READ | OBJ_PROP_FLAG_WRITE),
} ObjectPropertyFlags;

/**
 * object_property_add_uint8_ptr:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @v: pointer to value
 * @flags: bitwise-or'd ObjectPropertyFlags
 *
 * Add an integer property in memory.  This function will add a
 * property of type 'uint8'.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_uint8_ptr(Object *obj, const char *name,
                                              const uint8_t *v,
                                              ObjectPropertyFlags flags);

ObjectProperty *object_class_property_add_uint8_ptr(ObjectClass *klass,
                                         const char *name,
                                         const uint8_t *v,
                                         ObjectPropertyFlags flags);

/**
 * object_property_add_uint16_ptr:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @v: pointer to value
 * @flags: bitwise-or'd ObjectPropertyFlags
 *
 * Add an integer property in memory.  This function will add a
 * property of type 'uint16'.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_uint16_ptr(Object *obj, const char *name,
                                    const uint16_t *v,
                                    ObjectPropertyFlags flags);

ObjectProperty *object_class_property_add_uint16_ptr(ObjectClass *klass,
                                          const char *name,
                                          const uint16_t *v,
                                          ObjectPropertyFlags flags);

/**
 * object_property_add_uint32_ptr:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @v: pointer to value
 * @flags: bitwise-or'd ObjectPropertyFlags
 *
 * Add an integer property in memory.  This function will add a
 * property of type 'uint32'.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_uint32_ptr(Object *obj, const char *name,
                                    const uint32_t *v,
                                    ObjectPropertyFlags flags);

ObjectProperty *object_class_property_add_uint32_ptr(ObjectClass *klass,
                                          const char *name,
                                          const uint32_t *v,
                                          ObjectPropertyFlags flags);

/**
 * object_property_add_uint64_ptr:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @v: pointer to value
 * @flags: bitwise-or'd ObjectPropertyFlags
 *
 * Add an integer property in memory.  This function will add a
 * property of type 'uint64'.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_uint64_ptr(Object *obj, const char *name,
                                    const uint64_t *v,
                                    ObjectPropertyFlags flags);

ObjectProperty *object_class_property_add_uint64_ptr(ObjectClass *klass,
                                          const char *name,
                                          const uint64_t *v,
                                          ObjectPropertyFlags flags);

/**
 * object_property_add_alias:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @target_obj: the object to forward property access to
 * @target_name: the name of the property on the forwarded object
 *
 * Add an alias for a property on an object.  This function will add a property
 * of the same type as the forwarded property.
 *
 * The caller must ensure that <code>@target_obj</code> stays alive as long as
 * this property exists.  In the case of a child object or an alias on the same
 * object this will be the case.  For aliases to other objects the caller is
 * responsible for taking a reference.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_alias(Object *obj, const char *name,
                               Object *target_obj, const char *target_name);

/**
 * object_property_add_const_link:
 * @obj: the object to add a property to
 * @name: the name of the property
 * @target: the object to be referred by the link
 *
 * Add an unmodifiable link for a property on an object.  This function will
 * add a property of type link<TYPE> where TYPE is the type of @target.
 *
 * The caller must ensure that @target stays alive as long as
 * this property exists.  In the case @target is a child of @obj,
 * this will be the case.  Otherwise, the caller is responsible for
 * taking a reference.
 *
 * Returns: The newly added property on success, or %NULL on failure.
 */
ObjectProperty *object_property_add_const_link(Object *obj, const char *name,
                                               Object *target);

/**
 * object_property_set_description:
 * @obj: the object owning the property
 * @name: the name of the property
 * @description: the description of the property on the object
 *
 * Set an object property's description.
 *
 * Returns: %true on success, %false on failure.
 */
void object_property_set_description(Object *obj, const char *name,
                                     const char *description);
void object_class_property_set_description(ObjectClass *klass, const char *name,
                                           const char *description);

/**
 * object_child_foreach:
 * @obj: the object whose children will be navigated
 * @fn: the iterator function to be called
 * @opaque: an opaque value that will be passed to the iterator
 *
 * Call @fn passing each child of @obj and @opaque to it, until @fn returns
 * non-zero.
 *
 * It is forbidden to add or remove children from @obj from the @fn
 * callback.
 *
 * Returns: The last value returned by @fn, or 0 if there is no child.
 */
int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
                         void *opaque);

/**
 * object_child_foreach_recursive:
 * @obj: the object whose children will be navigated
 * @fn: the iterator function to be called
 * @opaque: an opaque value that will be passed to the iterator
 *
 * Call @fn passing each child of @obj and @opaque to it, until @fn returns
 * non-zero. Calls recursively, all child nodes of @obj will also be passed
 * all the way down to the leaf nodes of the tree. Depth first ordering.
 *
 * It is forbidden to add or remove children from @obj (or its
 * child nodes) from the @fn callback.
 *
 * Returns: The last value returned by @fn, or 0 if there is no child.
 */
int object_child_foreach_recursive(Object *obj,
                                   int (*fn)(Object *child, void *opaque),
                                   void *opaque);
/**
 * container_get:
 * @root: root of the #path, e.g., object_get_root()
 * @path: path to the container
 *
 * Return a container object whose path is @path.  Create more containers
 * along the path if necessary.
 *
 * Returns: the container object.
 */
Object *container_get(Object *root, const char *path);

/**
 * object_type_get_instance_size:
 * @typename: Name of the Type whose instance_size is required
 *
 * Returns the instance_size of the given @typename.
 */
size_t object_type_get_instance_size(const char *typename);

/**
 * object_property_help:
 * @name: the name of the property
 * @type: the type of the property
 * @defval: the default value
 * @description: description of the property
 *
 * Returns: a user-friendly formatted string describing the property
 * for help purposes.
 */
char *object_property_help(const char *name, const char *type,
                           QObject *defval, const char *description);

G_DEFINE_AUTOPTR_CLEANUP_FUNC(Object, object_unref)

#endif