summaryrefslogtreecommitdiffstats
path: root/src/VBox/Runtime/r3/xml.cpp
blob: 0d9896794d0213628f6f2f32c58ee7f9e7f3f760 (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
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
/* $Id: xml.cpp $ */
/** @file
 * IPRT - XML Manipulation API.
 *
 * @note Not available in no-CRT mode because it relies too heavily on
 *       exceptions, as well as using std::list and std::map.
 */

/*
 * Copyright (C) 2007-2022 Oracle and/or its affiliates.
 *
 * This file is part of VirtualBox base platform packages, as
 * available from https://www.virtualbox.org.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, in version 3 of the
 * License.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <https://www.gnu.org/licenses>.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
 * in the VirtualBox distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 *
 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#include <iprt/cpp/xml.h>

#include <iprt/dir.h>
#include <iprt/file.h>
#include <iprt/err.h>
#include <iprt/log.h>
#include <iprt/param.h>
#include <iprt/path.h>
#include <iprt/cpp/lock.h>

#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libxml/globals.h>
#include <libxml/xmlIO.h>
#include <libxml/xmlsave.h>
#include <libxml/uri.h>

#include <libxml/xmlschemas.h>

#include <map>


/*********************************************************************************************************************************
*   Global Variables                                                                                                             *
*********************************************************************************************************************************/
/**
 * Global module initialization structure. This is to wrap non-reentrant bits
 * of libxml, among other things.
 *
 * The constructor and destructor of this structure are used to perform global
 * module initialization and cleanup. There must be only one global variable of
 * this structure.
 */
static class Global
{
public:

    Global()
    {
        /* Check the parser version. The docs say it will kill the app if
         * there is a serious version mismatch, but I couldn't find it in the
         * source code (it only prints the error/warning message to the console) so
         * let's leave it as is for informational purposes. */
        LIBXML_TEST_VERSION

        /* Init libxml */
        xmlInitParser();

        /* Save the default entity resolver before someone has replaced it */
        sxml.defaultEntityLoader = xmlGetExternalEntityLoader();
    }

    ~Global()
    {
        /* Shutdown libxml */
        xmlCleanupParser();
    }

    struct
    {
        xmlExternalEntityLoader defaultEntityLoader;

        /** Used to provide some thread safety missing in libxml2 (see e.g.
         *  XmlTreeBackend::read()) */
        RTCLockMtx lock;
    }
    sxml;  /* XXX naming this xml will break with gcc-3.3 */
} gGlobal;



namespace xml
{

////////////////////////////////////////////////////////////////////////////////
//
// Exceptions
//
////////////////////////////////////////////////////////////////////////////////

LogicError::LogicError(RT_SRC_POS_DECL)
    : RTCError(NULL)
{
    char *msg = NULL;
    RTStrAPrintf(&msg, "In '%s', '%s' at #%d",
                 pszFunction, pszFile, iLine);
    setWhat(msg);
    RTStrFree(msg);
}

XmlError::XmlError(xmlErrorPtr aErr)
{
    if (!aErr)
        throw EInvalidArg(RT_SRC_POS);

    char *msg = Format(aErr);
    setWhat(msg);
    RTStrFree(msg);
}

/**
 * Composes a single message for the given error. The caller must free the
 * returned string using RTStrFree() when no more necessary.
 */
/* static */ char *XmlError::Format(xmlErrorPtr aErr)
{
    const char *msg = aErr->message ? aErr->message : "<none>";
    size_t msgLen = strlen(msg);
    /* strip spaces, trailing EOLs and dot-like char */
    while (msgLen && strchr(" \n.?!", msg [msgLen - 1]))
        --msgLen;

    char *finalMsg = NULL;
    RTStrAPrintf(&finalMsg, "%.*s.\nLocation: '%s', line %d (%d), column %d",
                 msgLen, msg, aErr->file, aErr->line, aErr->int1, aErr->int2);

    return finalMsg;
}

EIPRTFailure::EIPRTFailure(int aRC, const char *pszContextFmt, ...)
    : RuntimeError(NULL)
    , mRC(aRC)
{
    va_list va;
    va_start(va, pszContextFmt);
    m_strMsg.printfVNoThrow(pszContextFmt, va);
    va_end(va);
    m_strMsg.appendPrintfNoThrow(" %Rrc (%Rrs)", aRC, aRC);
}

////////////////////////////////////////////////////////////////////////////////
//
// File Class
//
//////////////////////////////////////////////////////////////////////////////

struct File::Data
{
    Data(RTFILE a_hHandle, const char *a_pszFilename, bool a_fFlushOnClose)
        : strFileName(a_pszFilename)
        , handle(a_hHandle)
        , opened(a_hHandle != NIL_RTFILE)
        , flushOnClose(a_fFlushOnClose)
    { }

    ~Data()
    {
        if (flushOnClose)
        {
            RTFileFlush(handle);
            if (!strFileName.isEmpty())
                RTDirFlushParent(strFileName.c_str());
        }

        if (opened)
        {
            RTFileClose(handle);
            handle = NIL_RTFILE;
            opened = false;
        }
    }

    RTCString strFileName;
    RTFILE handle;
    bool opened : 1;
    bool flushOnClose : 1;
};

File::File(Mode aMode, const char *aFileName, bool aFlushIt /* = false */)
    : m(NULL)
{
    /* Try open the file first, as the destructor will not be invoked if we throw anything from here. For details see:
       https://stackoverflow.com/questions/9971782/destructor-not-invoked-when-an-exception-is-thrown-in-the-constructor */
    uint32_t flags = 0;
    const char *pcszMode = "???";
    switch (aMode)
    {
        /** @todo change to RTFILE_O_DENY_WRITE where appropriate. */
        case Mode_Read:
            flags = RTFILE_O_READ      | RTFILE_O_OPEN           | RTFILE_O_DENY_NONE;
            pcszMode = "reading";
            break;
        case Mode_WriteCreate:      // fail if file exists
            flags = RTFILE_O_WRITE     | RTFILE_O_CREATE         | RTFILE_O_DENY_NONE;
            pcszMode = "writing";
            break;
        case Mode_Overwrite:        // overwrite if file exists
            flags = RTFILE_O_WRITE     | RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE;
            pcszMode = "overwriting";
            break;
        case Mode_ReadWrite:
            flags = RTFILE_O_READWRITE | RTFILE_O_OPEN           | RTFILE_O_DENY_NONE;
            pcszMode = "reading/writing";
            break;
    }
    RTFILE hFile = NIL_RTFILE;
    int vrc = RTFileOpen(&hFile, aFileName, flags);
    if (RT_FAILURE(vrc))
        throw EIPRTFailure(vrc, "Runtime error opening '%s' for %s", aFileName, pcszMode);

    /* Now we can create the data and stuff: */
    try
    {
        m = new Data(hFile, aFileName, aFlushIt && (flags & RTFILE_O_ACCESS_MASK) != RTFILE_O_READ);
    }
    catch (std::bad_alloc &)
    {
        RTFileClose(hFile);
        throw;
    }
}

File::File(RTFILE aHandle, const char *aFileName /* = NULL */, bool aFlushIt /* = false */)
    : m(NULL)
{
    if (aHandle == NIL_RTFILE)
        throw EInvalidArg(RT_SRC_POS);

    m = new Data(aHandle, aFileName, aFlushIt);

    setPos(0);
}

File::~File()
{
    if (m)
    {
        delete m;
        m = NULL;
    }
}

const char *File::uri() const
{
    return m->strFileName.c_str();
}

uint64_t File::pos() const
{
    uint64_t p = 0;
    int vrc = RTFileSeek(m->handle, 0, RTFILE_SEEK_CURRENT, &p);
    if (RT_SUCCESS(vrc))
        return p;

    throw EIPRTFailure(vrc, "Runtime error seeking in file '%s'", m->strFileName.c_str());
}

void File::setPos(uint64_t aPos)
{
    uint64_t p = 0;
    unsigned method = RTFILE_SEEK_BEGIN;
    int vrc = VINF_SUCCESS;

    /* check if we overflow int64_t and move to INT64_MAX first */
    if ((int64_t)aPos < 0)
    {
        vrc = RTFileSeek(m->handle, INT64_MAX, method, &p);
        aPos -= (uint64_t)INT64_MAX;
        method = RTFILE_SEEK_CURRENT;
    }
    /* seek the rest */
    if (RT_SUCCESS(vrc))
        vrc = RTFileSeek(m->handle, (int64_t) aPos, method, &p);
    if (RT_SUCCESS(vrc))
        return;

    throw EIPRTFailure(vrc, "Runtime error seeking in file '%s'", m->strFileName.c_str());
}

int File::read(char *aBuf, int aLen)
{
    size_t len = aLen;
    int vrc = RTFileRead(m->handle, aBuf, len, &len);
    if (RT_SUCCESS(vrc))
        return (int)len;

    throw EIPRTFailure(vrc, "Runtime error reading from file '%s'", m->strFileName.c_str());
}

int File::write(const char *aBuf, int aLen)
{
    size_t len = aLen;
    int vrc = RTFileWrite(m->handle, aBuf, len, &len);
    if (RT_SUCCESS(vrc))
        return (int)len;

    throw EIPRTFailure(vrc, "Runtime error writing to file '%s'", m->strFileName.c_str());
}

void File::truncate()
{
    int vrc = RTFileSetSize(m->handle, pos());
    if (RT_SUCCESS(vrc))
        return;

    throw EIPRTFailure(vrc, "Runtime error truncating file '%s'", m->strFileName.c_str());
}

////////////////////////////////////////////////////////////////////////////////
//
// MemoryBuf Class
//
//////////////////////////////////////////////////////////////////////////////

struct MemoryBuf::Data
{
    Data()
        : buf(NULL), len(0), uri(NULL), pos(0) {}

    const char *buf;
    size_t len;
    char *uri;

    size_t pos;
};

MemoryBuf::MemoryBuf(const char *aBuf, size_t aLen, const char *aURI /* = NULL */)
    : m(new Data())
{
    if (aBuf == NULL)
        throw EInvalidArg(RT_SRC_POS);

    m->buf = aBuf;
    m->len = aLen;
    m->uri = RTStrDup(aURI);
}

MemoryBuf::~MemoryBuf()
{
    RTStrFree(m->uri);
}

const char *MemoryBuf::uri() const
{
    return m->uri;
}

uint64_t MemoryBuf::pos() const
{
    return m->pos;
}

void MemoryBuf::setPos(uint64_t aPos)
{
    size_t off = (size_t)aPos;
    if ((uint64_t) off != aPos)
        throw EInvalidArg();

    if (off > m->len)
        throw EInvalidArg();

    m->pos = off;
}

int MemoryBuf::read(char *aBuf, int aLen)
{
    if (m->pos >= m->len)
        return 0 /* nothing to read */;

    size_t len = m->pos + aLen < m->len ? aLen : m->len - m->pos;
    memcpy(aBuf, m->buf + m->pos, len);
    m->pos += len;

    return (int)len;
}

////////////////////////////////////////////////////////////////////////////////
//
// GlobalLock class
//
////////////////////////////////////////////////////////////////////////////////

struct GlobalLock::Data
{
    PFNEXTERNALENTITYLOADER pfnOldLoader;
    RTCLock lock;

    Data()
        : pfnOldLoader(NULL)
        , lock(gGlobal.sxml.lock)
    {
    }
};

GlobalLock::GlobalLock()
    : m(new Data())
{
}

GlobalLock::~GlobalLock()
{
    if (m->pfnOldLoader)
        xmlSetExternalEntityLoader(m->pfnOldLoader);
    delete m;
    m = NULL;
}

void GlobalLock::setExternalEntityLoader(PFNEXTERNALENTITYLOADER pfnLoader)
{
    m->pfnOldLoader = (PFNEXTERNALENTITYLOADER)xmlGetExternalEntityLoader();
    xmlSetExternalEntityLoader(pfnLoader);
}

// static
xmlParserInput* GlobalLock::callDefaultLoader(const char *aURI,
                                              const char *aID,
                                              xmlParserCtxt *aCtxt)
{
    return gGlobal.sxml.defaultEntityLoader(aURI, aID, aCtxt);
}



////////////////////////////////////////////////////////////////////////////////
//
// Node class
//
////////////////////////////////////////////////////////////////////////////////

Node::Node(EnumType type,
           Node *pParent,
           PRTLISTANCHOR pListAnchor,
           xmlNode *pLibNode,
           xmlAttr *pLibAttr)
    : m_Type(type)
    , m_pParent(pParent)
    , m_pLibNode(pLibNode)
    , m_pLibAttr(pLibAttr)
    , m_pcszNamespacePrefix(NULL)
    , m_pcszNamespaceHref(NULL)
    , m_pcszName(NULL)
    , m_pParentListAnchor(pListAnchor)
{
    RTListInit(&m_listEntry);
}

Node::~Node()
{
}

/**
 * Returns the name of the node, which is either the element name or
 * the attribute name. For other node types it probably returns NULL.
 * @return
 */
const char *Node::getName() const
{
    return m_pcszName;
}

/**
 * Returns the name of the node, which is either the element name or
 * the attribute name. For other node types it probably returns NULL.
 * @return
 */
const char *Node::getPrefix() const
{
    return m_pcszNamespacePrefix;
}

/**
 * Returns the XML namespace URI, which is the attribute name. For other node types it probably
 * returns NULL.
 * @return
 */
const char *Node::getNamespaceURI() const
{
    return m_pcszNamespaceHref;
}

/**
 * Variant of nameEquals that checks the namespace as well.
 * @param pcszNamespace
 * @param pcsz
 * @return
 */
bool Node::nameEqualsNS(const char *pcszNamespace, const char *pcsz) const
{
    if (m_pcszName == pcsz)
        return true;
    if (m_pcszName == NULL)
        return false;
    if (pcsz == NULL)
        return false;
    if (strcmp(m_pcszName, pcsz))
        return false;

    // name matches: then check namespaces as well
    if (!pcszNamespace)
        return true;
    // caller wants namespace:
    if (!m_pcszNamespacePrefix)
        // but node has no namespace:
        return false;
    return !strcmp(m_pcszNamespacePrefix, pcszNamespace);
}

/**
 * Variant of nameEquals that checks the namespace as well.
 *
 * @returns true if equal, false if not.
 * @param   pcsz            The element name.
 * @param   cchMax          The maximum number of character from @a pcsz to
 *                          match.
 * @param   pcszNamespace   The name space prefix or NULL (default).
 */
bool Node::nameEqualsN(const char *pcsz, size_t cchMax, const char *pcszNamespace /* = NULL*/) const
{
    /* Match the name. */
    if (!m_pcszName)
        return false;
    if (!pcsz || cchMax == 0)
        return false;
    if (strncmp(m_pcszName, pcsz, cchMax))
        return false;
    if (strlen(m_pcszName) > cchMax)
        return false;

    /* Match name space. */
    if (!pcszNamespace)
        return true;    /* NULL, anything goes. */
    if (!m_pcszNamespacePrefix)
        return false;   /* Element has no namespace. */
    return !strcmp(m_pcszNamespacePrefix, pcszNamespace);
}

/**
 * Returns the value of a node. If this node is an attribute, returns
 * the attribute value; if this node is an element, then this returns
 * the element text content.
 * @return
 */
const char *Node::getValue() const
{
    if (   m_pLibAttr
        && m_pLibAttr->children
        )
        // libxml hides attribute values in another node created as a
        // single child of the attribute node, and it's in the content field
        return (const char *)m_pLibAttr->children->content;

    if (   m_pLibNode
        && m_pLibNode->children)
        return (const char *)m_pLibNode->children->content;

    return NULL;
}

/**
 * Returns the value of a node. If this node is an attribute, returns
 * the attribute value; if this node is an element, then this returns
 * the element text content.
 * @return
 * @param   cchValueLimit   If the length of the returned value exceeds this
 *                          limit a EIPRTFailure exception will be thrown.
 */
const char *Node::getValueN(size_t cchValueLimit) const
{
    if (   m_pLibAttr
        && m_pLibAttr->children
        )
    {
        // libxml hides attribute values in another node created as a
        // single child of the attribute node, and it's in the content field
        AssertStmt(strlen((const char *)m_pLibAttr->children->content) <= cchValueLimit, throw EIPRTFailure(VERR_BUFFER_OVERFLOW, "Attribute '%s' exceeds limit of %zu bytes", m_pcszName, cchValueLimit));
        return (const char *)m_pLibAttr->children->content;
    }

    if (   m_pLibNode
        && m_pLibNode->children)
    {
        AssertStmt(strlen((const char *)m_pLibNode->children->content) <= cchValueLimit, throw EIPRTFailure(VERR_BUFFER_OVERFLOW, "Element '%s' exceeds limit of %zu bytes", m_pcszName, cchValueLimit));
        return (const char *)m_pLibNode->children->content;
    }

    return NULL;
}

/**
 * Copies the value of a node into the given integer variable.
 * Returns TRUE only if a value was found and was actually an
 * integer of the given type.
 * @return
 */
bool Node::copyValue(int32_t &i) const
{
    const char *pcsz;
    if (    ((pcsz = getValue()))
         && (VINF_SUCCESS == RTStrToInt32Ex(pcsz, NULL, 10, &i))
       )
        return true;

    return false;
}

/**
 * Copies the value of a node into the given integer variable.
 * Returns TRUE only if a value was found and was actually an
 * integer of the given type.
 * @return
 */
bool Node::copyValue(uint32_t &i) const
{
    const char *pcsz;
    if (    ((pcsz = getValue()))
         && (VINF_SUCCESS == RTStrToUInt32Ex(pcsz, NULL, 10, &i))
       )
        return true;

    return false;
}

/**
 * Copies the value of a node into the given integer variable.
 * Returns TRUE only if a value was found and was actually an
 * integer of the given type.
 * @return
 */
bool Node::copyValue(int64_t &i) const
{
    const char *pcsz;
    if (    ((pcsz = getValue()))
         && (VINF_SUCCESS == RTStrToInt64Ex(pcsz, NULL, 10, &i))
       )
        return true;

    return false;
}

/**
 * Copies the value of a node into the given integer variable.
 * Returns TRUE only if a value was found and was actually an
 * integer of the given type.
 * @return
 */
bool Node::copyValue(uint64_t &i) const
{
    const char *pcsz;
    if (    ((pcsz = getValue()))
         && (VINF_SUCCESS == RTStrToUInt64Ex(pcsz, NULL, 10, &i))
       )
        return true;

    return false;
}

/**
 * Returns the line number of the current node in the source XML file.
 * Useful for error messages.
 * @return
 */
int Node::getLineNumber() const
{
    if (m_pLibAttr)
        return m_pParent->m_pLibNode->line;

    return m_pLibNode->line;
}

/**
 * Private element constructor.
 *
 * @param   pElmRoot    Pointer to the root element.
 * @param   pParent     Pointer to the parent element (always an ElementNode,
 *                      despite the type).  NULL for the root node.
 * @param   pListAnchor Pointer to the m_children member of the parent.  NULL
 *                      for the root node.
 * @param   pLibNode    Pointer to the libxml2 node structure.
 */
ElementNode::ElementNode(const ElementNode *pElmRoot,
                         Node *pParent,
                         PRTLISTANCHOR pListAnchor,
                         xmlNode *pLibNode)
    : Node(IsElement,
           pParent,
           pListAnchor,
           pLibNode,
           NULL)
{
    m_pElmRoot = pElmRoot ? pElmRoot : this; // If NULL is passed, then this is the root element.
    m_pcszName = (const char *)pLibNode->name;

    if (pLibNode->ns)
    {
        m_pcszNamespacePrefix = (const char *)m_pLibNode->ns->prefix;
        m_pcszNamespaceHref = (const char *)m_pLibNode->ns->href;
    }

    RTListInit(&m_children);
    RTListInit(&m_attributes);
}

ElementNode::~ElementNode()
{
    Node *pCur, *pNext;
    RTListForEachSafeCpp(&m_children, pCur, pNext, Node, m_listEntry)
    {
        delete pCur;
    }
    RTListInit(&m_children);

    RTListForEachSafeCpp(&m_attributes, pCur, pNext, Node, m_listEntry)
    {
        delete pCur;
    }
    RTListInit(&m_attributes);
}


/**
 * Gets the next tree element in a full tree enumeration.
 *
 * @returns Pointer to the next element in the tree, NULL if we're done.
 * @param   pElmRoot            The root of the tree we're enumerating.  NULL if
 *                              it's the entire tree.
 */
ElementNode const *ElementNode::getNextTreeElement(ElementNode const *pElmRoot /*= NULL */) const
{
    /*
     * Consider children first.
     */
    ElementNode const *pChild = getFirstChildElement();
    if (pChild)
        return pChild;

    /*
     * Then siblings, aunts and uncles.
     */
    ElementNode const *pCur = this;
    do
    {
        ElementNode const *pSibling = pCur->getNextSibilingElement();
        if (pSibling != NULL)
            return pSibling;

        pCur = static_cast<const xml::ElementNode *>(pCur->m_pParent);
        Assert(pCur || pCur == pElmRoot);
    } while (pCur != pElmRoot);

    return NULL;
}


/**
 * Private implementation.
 *
 * @param   pElmRoot        The root element.
 */
/*static*/ void ElementNode::buildChildren(ElementNode *pElmRoot)       // protected
{
    for (ElementNode *pCur = pElmRoot; pCur; pCur = pCur->getNextTreeElement(pElmRoot))
    {
        /*
         * Go thru this element's attributes creating AttributeNodes for them.
         */
        for (xmlAttr *pLibAttr = pCur->m_pLibNode->properties; pLibAttr; pLibAttr = pLibAttr->next)
        {
            AttributeNode *pNew = new AttributeNode(pElmRoot, pCur, &pCur->m_attributes, pLibAttr);
            RTListAppend(&pCur->m_attributes, &pNew->m_listEntry);
        }

        /*
         * Go thru this element's child elements (element and text nodes).
         */
        for (xmlNodePtr pLibNode = pCur->m_pLibNode->children; pLibNode; pLibNode = pLibNode->next)
        {
            Node *pNew;
            if (pLibNode->type == XML_ELEMENT_NODE)
                pNew = new ElementNode(pElmRoot, pCur, &pCur->m_children, pLibNode);
            else if (pLibNode->type == XML_TEXT_NODE)
                pNew = new ContentNode(pCur, &pCur->m_children, pLibNode);
            else
                continue;
            RTListAppend(&pCur->m_children, &pNew->m_listEntry);
        }
    }
}


/**
 * Builds a list of direct child elements of the current element that
 * match the given string; if pcszMatch is NULL, all direct child
 * elements are returned.
 * @param children out: list of nodes to which children will be appended.
 * @param pcszMatch in: match string, or NULL to return all children.
 * @return Number of items appended to the list (0 if none).
 */
int ElementNode::getChildElements(ElementNodesList &children,
                                  const char *pcszMatch /*= NULL*/)
    const
{
    int i = 0;
    Node *p;
    RTListForEachCpp(&m_children, p, Node, m_listEntry)
    {
        // export this child node if ...
        if (p->isElement())
            if (   !pcszMatch                       // ... the caller wants all nodes or ...
                || !strcmp(pcszMatch, p->getName()) // ... the element name matches.
               )
            {
                children.push_back(static_cast<ElementNode *>(p));
                ++i;
            }
    }
    return i;
}

/**
 * Returns the first child element whose name matches pcszMatch.
 *
 * @param pcszNamespace Namespace prefix (e.g. "vbox") or NULL to match any namespace.
 * @param pcszMatch Element name to match.
 * @return
 */
const ElementNode *ElementNode::findChildElementNS(const char *pcszNamespace, const char *pcszMatch) const
{
    Node *p;
    RTListForEachCpp(&m_children, p, Node, m_listEntry)
    {
        if (p->isElement())
        {
            ElementNode *pelm = static_cast<ElementNode*>(p);
            if (pelm->nameEqualsNS(pcszNamespace, pcszMatch))
                return pelm;
        }
    }
    return NULL;
}

/**
 * Returns the first child element whose "id" attribute matches pcszId.
 * @param pcszId identifier to look for.
 * @return child element or NULL if not found.
 */
const ElementNode *ElementNode::findChildElementFromId(const char *pcszId) const
{
    const Node *p;
    RTListForEachCpp(&m_children, p, Node, m_listEntry)
    {
        if (p->isElement())
        {
            const ElementNode   *pElm  = static_cast<const ElementNode *>(p);
            const AttributeNode *pAttr = pElm->findAttribute("id");
            if (pAttr && !strcmp(pAttr->getValue(), pcszId))
                return pElm;
        }
    }
    return NULL;
}


const ElementNode *ElementNode::findChildElementP(const char *pcszPath, const char *pcszNamespace /*= NULL*/) const
{
    size_t cchThis = strchr(pcszPath, '/') - pcszPath;
    if (cchThis == (size_t)((const char *)0 - pcszPath))
        return findChildElementNS(pcszNamespace, pcszPath);

    /** @todo Can be done without recursion as we have both sibling lists and parent
     *        pointers in this variant.  */
    const Node *p;
    RTListForEachCpp(&m_children, p, Node, m_listEntry)
    {
        if (p->isElement())
        {
            const ElementNode *pElm = static_cast<const ElementNode *>(p);
            if (pElm->nameEqualsN(pcszPath, cchThis, pcszNamespace))
            {
                pElm = findChildElementP(pcszPath + cchThis, pcszNamespace);
                if (pElm)
                    return pElm;
            }
        }
    }

    return NULL;
}

const ElementNode *ElementNode::getFirstChildElement() const
{
    const Node *p;
    RTListForEachCpp(&m_children, p, Node, m_listEntry)
    {
        if (p->isElement())
            return static_cast<const ElementNode *>(p);
    }
    return NULL;
}

const ElementNode *ElementNode::getLastChildElement() const
{
    const Node *p;
    RTListForEachReverseCpp(&m_children, p, Node, m_listEntry)
    {
        if (p->isElement())
            return static_cast<const ElementNode *>(p);
    }
    return NULL;
}

const ElementNode *ElementNode::getPrevSibilingElement() const
{
    if (!m_pParent)
        return NULL;
    const Node *pSibling = this;
    for (;;)
    {
        pSibling = RTListGetPrevCpp(m_pParentListAnchor, pSibling, const Node, m_listEntry);
        if (!pSibling)
            return NULL;
        if (pSibling->isElement())
            return static_cast<const ElementNode *>(pSibling);
    }
}

const ElementNode *ElementNode::getNextSibilingElement() const
{
    if (!m_pParent)
        return NULL;
    const Node *pSibling = this;
    for (;;)
    {
        pSibling = RTListGetNextCpp(m_pParentListAnchor, pSibling, const Node, m_listEntry);
        if (!pSibling)
            return NULL;
        if (pSibling->isElement())
            return static_cast<const ElementNode *>(pSibling);
    }
}

const ElementNode *ElementNode::findPrevSibilingElement(const char *pcszMatch, const char *pcszNamespace /*= NULL*/) const
{
    if (!m_pParent)
        return NULL;
    const Node *pSibling = this;
    for (;;)
    {
        pSibling = RTListGetPrevCpp(m_pParentListAnchor, pSibling, const Node, m_listEntry);
        if (!pSibling)
            return NULL;
        if (pSibling->isElement())
        {
            const ElementNode *pElem = static_cast<const ElementNode *>(pSibling);
            if (pElem->nameEqualsNS(pcszNamespace, pcszMatch))
                return pElem;
        }
    }
}

const ElementNode *ElementNode::findNextSibilingElement(const char *pcszMatch, const char *pcszNamespace /*= NULL*/) const
{
    if (!m_pParent)
        return NULL;
    const Node *pSibling = this;
    for (;;)
    {
        pSibling = RTListGetNextCpp(m_pParentListAnchor, pSibling, const Node, m_listEntry);
        if (!pSibling)
            return NULL;
        if (pSibling->isElement())
        {
            const ElementNode *pElem = static_cast<const ElementNode *>(pSibling);
            if (pElem->nameEqualsNS(pcszNamespace, pcszMatch))
                return pElem;
        }
    }
}


/**
 * Looks up the given attribute node in this element's attribute map.
 *
 * @param   pcszMatch       The name of the attribute to find.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 */
const AttributeNode *ElementNode::findAttribute(const char *pcszMatch, const char *pcszNamespace /*= NULL*/) const
{
    AttributeNode *p;
    RTListForEachCpp(&m_attributes, p, AttributeNode, m_listEntry)
    {
        if (p->nameEqualsNS(pcszNamespace, pcszMatch))
            return p;
    }
    return NULL;
}

/**
 * Convenience method which attempts to find the attribute with the given
 * name and returns its value as a string.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   ppcsz           Where to return the attribute.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 */
bool ElementNode::getAttributeValue(const char *pcszMatch, const char **ppcsz, const char *pcszNamespace /*= NULL*/) const
{
    const AttributeNode *pAttr = findAttribute(pcszMatch, pcszNamespace);
    if (pAttr)
    {
        *ppcsz = pAttr->getValue();
        return true;
    }
    return false;
}

/**
 * Convenience method which attempts to find the attribute with the given
 * name and returns its value as a string.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   pStr            Pointer to the string object that should receive the
 *                          attribute value.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 *
 * @throws  Whatever the string class may throw on assignment.
 */
bool ElementNode::getAttributeValue(const char *pcszMatch, RTCString *pStr, const char *pcszNamespace /*= NULL*/) const
{
    const AttributeNode *pAttr = findAttribute(pcszMatch, pcszNamespace);
    if (pAttr)
    {
        *pStr = pAttr->getValue();
        return true;
    }

    return false;
}

/**
 * Like getAttributeValue (ministring variant), but makes sure that all backslashes
 * are converted to forward slashes.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   pStr            Pointer to the string object that should
 *                          receive the attribute path value.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 */
bool ElementNode::getAttributeValuePath(const char *pcszMatch, RTCString *pStr, const char *pcszNamespace /*= NULL*/) const
{
    if (getAttributeValue(pcszMatch, pStr, pcszNamespace))
    {
        pStr->findReplace('\\', '/');
        return true;
    }

    return false;
}

/**
 * Convenience method which attempts to find the attribute with the given
 * name and returns its value as a signed 32-bit integer.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   piValue         Where to return the value.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 */
bool ElementNode::getAttributeValue(const char *pcszMatch, int32_t *piValue, const char *pcszNamespace /*= NULL*/) const
{
    const char *pcsz = findAttributeValue(pcszMatch, pcszNamespace);
    if (pcsz)
    {
        int rc = RTStrToInt32Ex(pcsz, NULL, 0, piValue);
        if (rc == VINF_SUCCESS)
            return true;
    }
    return false;
}

/**
 * Convenience method which attempts to find the attribute with the given
 * name and returns its value as an unsigned 32-bit integer.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   puValue         Where to return the value.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 */
bool ElementNode::getAttributeValue(const char *pcszMatch, uint32_t *puValue, const char *pcszNamespace /*= NULL*/) const
{
    const char *pcsz = findAttributeValue(pcszMatch, pcszNamespace);
    if (pcsz)
    {
        int rc = RTStrToUInt32Ex(pcsz, NULL, 0, puValue);
        if (rc == VINF_SUCCESS)
            return true;
    }
    return false;
}

/**
 * Convenience method which attempts to find the attribute with the given
 * name and returns its value as a signed 64-bit integer.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   piValue         Where to return the value.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 */
bool ElementNode::getAttributeValue(const char *pcszMatch, int64_t *piValue, const char *pcszNamespace /*= NULL*/) const
{
    const char *pcsz = findAttributeValue(pcszMatch, pcszNamespace);
    if (pcsz)
    {
        int rc = RTStrToInt64Ex(pcsz, NULL, 0, piValue);
        if (rc == VINF_SUCCESS)
            return true;
    }
    return false;
}

/**
 * Convenience method which attempts to find the attribute with the given
 * name and returns its value as an unsigned 64-bit integer.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   puValue         Where to return the value.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 */
bool ElementNode::getAttributeValue(const char *pcszMatch, uint64_t *puValue, const char *pcszNamespace /*= NULL*/) const
{
    const char *pcsz = findAttributeValue(pcszMatch, pcszNamespace);
    if (pcsz)
    {
        int rc = RTStrToUInt64Ex(pcsz, NULL, 0, puValue);
        if (rc == VINF_SUCCESS)
            return true;
    }
    return false;
}

/**
 * Convenience method which attempts to find the attribute with the given
 * name and returns its value as a boolean. This accepts "true", "false",
 * "yes", "no", "1" or "0" as valid values.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   pfValue         Where to return the value.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 */
bool ElementNode::getAttributeValue(const char *pcszMatch, bool *pfValue, const char *pcszNamespace /*= NULL*/) const
{
    const char *pcsz = findAttributeValue(pcszMatch, pcszNamespace);
    if (pcsz)
    {
        if (   !strcmp(pcsz, "true")
            || !strcmp(pcsz, "yes")
            || !strcmp(pcsz, "1")
           )
        {
            *pfValue = true;
            return true;
        }
        if (   !strcmp(pcsz, "false")
            || !strcmp(pcsz, "no")
            || !strcmp(pcsz, "0")
           )
        {
            *pfValue = false;
            return true;
        }
    }

    return false;
}

/**
 * Convenience method which attempts to find the attribute with the given
 * name and returns its value as a string.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   ppcsz           Where to return the attribute.
 * @param   cchValueLimit   If the length of the returned value exceeds this
 *                          limit a EIPRTFailure exception will be thrown.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 */
bool ElementNode::getAttributeValueN(const char *pcszMatch, const char **ppcsz, size_t cchValueLimit, const char *pcszNamespace /*= NULL*/) const
{
    const AttributeNode *pAttr = findAttribute(pcszMatch, pcszNamespace);
    if (pAttr)
    {
        *ppcsz = pAttr->getValueN(cchValueLimit);
        return true;
    }
    return false;
}

/**
 * Convenience method which attempts to find the attribute with the given
 * name and returns its value as a string.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   pStr            Pointer to the string object that should receive the
 *                          attribute value.
 * @param   cchValueLimit   If the length of the returned value exceeds this
 *                          limit a EIPRTFailure exception will be thrown.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 *
 * @throws  Whatever the string class may throw on assignment.
 */
bool ElementNode::getAttributeValueN(const char *pcszMatch, RTCString *pStr, size_t cchValueLimit, const char *pcszNamespace /*= NULL*/) const
{
    const AttributeNode *pAttr = findAttribute(pcszMatch, pcszNamespace);
    if (pAttr)
    {
        *pStr = pAttr->getValueN(cchValueLimit);
        return true;
    }

    return false;
}

/**
 * Like getAttributeValue (ministring variant), but makes sure that all backslashes
 * are converted to forward slashes.
 *
 * @param   pcszMatch       Name of attribute to find.
 * @param   pStr            Pointer to the string object that should
 *                          receive the attribute path value.
 * @param   cchValueLimit   If the length of the returned value exceeds this
 *                          limit a EIPRTFailure exception will be thrown.
 * @param   pcszNamespace   The attribute name space prefix or NULL.
 * @returns Boolean success indicator.
 */
bool ElementNode::getAttributeValuePathN(const char *pcszMatch, RTCString *pStr, size_t cchValueLimit, const char *pcszNamespace /*= NULL*/) const
{
    if (getAttributeValueN(pcszMatch, pStr, cchValueLimit, pcszNamespace))
    {
        pStr->findReplace('\\', '/');
        return true;
    }

    return false;
}


bool ElementNode::getElementValue(int32_t *piValue) const
{
    const char *pszValue = getValue();
    if (pszValue)
    {
        int rc = RTStrToInt32Ex(pszValue, NULL, 0, piValue);
        if (rc == VINF_SUCCESS)
            return true;
    }
    return false;
}

bool ElementNode::getElementValue(uint32_t *puValue) const
{
    const char *pszValue = getValue();
    if (pszValue)
    {
        int rc = RTStrToUInt32Ex(pszValue, NULL, 0, puValue);
        if (rc == VINF_SUCCESS)
            return true;
    }
    return false;
}

bool ElementNode::getElementValue(int64_t *piValue) const
{
    const char *pszValue = getValue();
    if (pszValue)
    {
        int rc = RTStrToInt64Ex(pszValue, NULL, 0, piValue);
        if (rc == VINF_SUCCESS)
            return true;
    }
    return false;
}

bool ElementNode::getElementValue(uint64_t *puValue) const
{
    const char *pszValue = getValue();
    if (pszValue)
    {
        int rc = RTStrToUInt64Ex(pszValue, NULL, 0, puValue);
        if (rc == VINF_SUCCESS)
            return true;
    }
    return false;
}

bool ElementNode::getElementValue(bool *pfValue) const
{
    const char *pszValue = getValue();
    if (pszValue)
    {
        if (   !strcmp(pszValue, "true")
            || !strcmp(pszValue, "yes")
            || !strcmp(pszValue, "1")
           )
        {
            *pfValue = true;
            return true;
        }
        if (   !strcmp(pszValue, "false")
            || !strcmp(pszValue, "no")
            || !strcmp(pszValue, "0")
           )
        {
            *pfValue = true;
            return true;
        }
    }
    return false;
}


/**
 * Creates a new child element node and appends it to the list
 * of children in "this".
 *
 * @param pcszElementName
 * @return
 */
ElementNode *ElementNode::createChild(const char *pcszElementName)
{
    // we must be an element, not an attribute
    if (!m_pLibNode)
        throw ENodeIsNotElement(RT_SRC_POS);

    // libxml side: create new node
    xmlNode *pLibNode;
    if (!(pLibNode = xmlNewNode(NULL,        // namespace
                                (const xmlChar*)pcszElementName)))
        throw std::bad_alloc();
    xmlAddChild(m_pLibNode, pLibNode);

    // now wrap this in C++
    ElementNode *p = new ElementNode(m_pElmRoot, this, &m_children, pLibNode);
    RTListAppend(&m_children, &p->m_listEntry);

    return p;
}


/**
 * Creates a content node and appends it to the list of children
 * in "this".
 *
 * @param pcszContent
 * @return
 */
ContentNode *ElementNode::addContent(const char *pcszContent)
{
    // libxml side: create new node
    xmlNode *pLibNode = xmlNewText((const xmlChar*)pcszContent);
    if (!pLibNode)
        throw std::bad_alloc();
    xmlAddChild(m_pLibNode, pLibNode);

    // now wrap this in C++
    ContentNode *p = new ContentNode(this, &m_children, pLibNode);
    RTListAppend(&m_children, &p->m_listEntry);

    return p;
}

/**
 * Changes the contents of node and appends it to the list of
 * children
 *
 * @param pcszContent
 * @return
 */
ContentNode *ElementNode::setContent(const char *pcszContent)
{
//  1. Update content
    xmlNodeSetContent(m_pLibNode, (const xmlChar*)pcszContent);

//  2. Remove Content node from the list
    /* Check that the order is right. */
    xml::Node * pNode;
    RTListForEachCpp(&m_children, pNode, xml::Node, m_listEntry)
    {
        bool fLast = RTListNodeIsLast(&m_children, &pNode->m_listEntry);

        if (pNode->isContent())
        {
            RTListNodeRemove(&pNode->m_listEntry);
        }

        if (fLast)
            break;
    }

//  3. Create a new node and append to the list
    // now wrap this in C++
    ContentNode *pCNode = new ContentNode(this, &m_children, m_pLibNode);
    RTListAppend(&m_children, &pCNode->m_listEntry);

    return pCNode;
}

/**
 * Sets the given attribute; overloaded version for const char *.
 *
 * If an attribute with the given name exists, it is overwritten,
 * otherwise a new attribute is created. Returns the attribute node
 * that was either created or changed.
 *
 * @param   pcszName        The attribute name.
 * @param   pcszValue       The attribute value.
 * @return  Pointer to the attribute node that was created or modified.
 */
AttributeNode *ElementNode::setAttribute(const char *pcszName, const char *pcszValue)
{
    /*
     * Do we already have an attribute and should we just update it?
     */
    AttributeNode *pAttr;
    RTListForEachCpp(&m_attributes, pAttr, AttributeNode, m_listEntry)
    {
        if (pAttr->nameEquals(pcszName))
        {
            /* Overwrite existing libxml attribute node ... */
            xmlAttrPtr pLibAttr = xmlSetProp(m_pLibNode, (xmlChar *)pcszName, (xmlChar *)pcszValue);

            /* ... and update our C++ wrapper in case the attrib pointer changed. */
            pAttr->m_pLibAttr = pLibAttr;
            return pAttr;
        }
    }

    /*
     * No existing attribute, create a new one.
     */
    /* libxml side: xmlNewProp creates an attribute. */
    xmlAttr *pLibAttr = xmlNewProp(m_pLibNode, (xmlChar *)pcszName, (xmlChar *)pcszValue);

    /* C++ side: Create an attribute node around it. */
    pAttr = new AttributeNode(m_pElmRoot, this, &m_attributes, pLibAttr);
    RTListAppend(&m_attributes, &pAttr->m_listEntry);

    return pAttr;
}

/**
 * Like setAttribute (ministring variant), but replaces all backslashes with forward slashes
 * before calling that one.
 * @param pcszName
 * @param strValue
 * @return
 */
AttributeNode* ElementNode::setAttributePath(const char *pcszName, const RTCString &strValue)
{
    RTCString strTemp(strValue);
    strTemp.findReplace('\\', '/');
    return setAttribute(pcszName, strTemp.c_str());
}

/**
 * Sets the given attribute; overloaded version for int32_t.
 *
 * If an attribute with the given name exists, it is overwritten,
 * otherwise a new attribute is created. Returns the attribute node
 * that was either created or changed.
 *
 * @param pcszName
 * @param i
 * @return
 */
AttributeNode* ElementNode::setAttribute(const char *pcszName, int32_t i)
{
    char szValue[12];  // negative sign + 10 digits + \0
    RTStrPrintf(szValue, sizeof(szValue), "%RI32", i);
    AttributeNode *p = setAttribute(pcszName, szValue);
    return p;
}

/**
 * Sets the given attribute; overloaded version for uint32_t.
 *
 * If an attribute with the given name exists, it is overwritten,
 * otherwise a new attribute is created. Returns the attribute node
 * that was either created or changed.
 *
 * @param pcszName
 * @param u
 * @return
 */
AttributeNode* ElementNode::setAttribute(const char *pcszName, uint32_t u)
{
    char szValue[11];  // 10 digits + \0
    RTStrPrintf(szValue, sizeof(szValue), "%RU32", u);
    AttributeNode *p = setAttribute(pcszName, szValue);
    return p;
}

/**
 * Sets the given attribute; overloaded version for int64_t.
 *
 * If an attribute with the given name exists, it is overwritten,
 * otherwise a new attribute is created. Returns the attribute node
 * that was either created or changed.
 *
 * @param pcszName
 * @param i
 * @return
 */
AttributeNode* ElementNode::setAttribute(const char *pcszName, int64_t i)
{
    char szValue[21];  // negative sign + 19 digits + \0
    RTStrPrintf(szValue, sizeof(szValue), "%RI64", i);
    AttributeNode *p = setAttribute(pcszName, szValue);
    return p;
}

/**
 * Sets the given attribute; overloaded version for uint64_t.
 *
 * If an attribute with the given name exists, it is overwritten,
 * otherwise a new attribute is created. Returns the attribute node
 * that was either created or changed.
 *
 * @param pcszName
 * @param u
 * @return
 */
AttributeNode* ElementNode::setAttribute(const char *pcszName, uint64_t u)
{
    char szValue[21];  // 20 digits + \0
    RTStrPrintf(szValue, sizeof(szValue), "%RU64", u);
    AttributeNode *p = setAttribute(pcszName, szValue);
    return p;
}

/**
 * Sets the given attribute to the given uint32_t, outputs a hexadecimal string.
 *
 * If an attribute with the given name exists, it is overwritten,
 * otherwise a new attribute is created. Returns the attribute node
 * that was either created or changed.
 *
 * @param pcszName
 * @param u
 * @return
 */
AttributeNode* ElementNode::setAttributeHex(const char *pcszName, uint32_t u)
{
    char szValue[11];  // "0x" + 8 digits + \0
    RTStrPrintf(szValue, sizeof(szValue), "0x%RX32", u);
    AttributeNode *p = setAttribute(pcszName, szValue);
    return p;
}

/**
 * Sets the given attribute; overloaded version for bool.
 *
 * If an attribute with the given name exists, it is overwritten,
 * otherwise a new attribute is created. Returns the attribute node
 * that was either created or changed.
 *
 * @param   pcszName    The attribute name.
 * @param   f           The attribute value.
 * @return
 */
AttributeNode* ElementNode::setAttribute(const char *pcszName, bool f)
{
    return setAttribute(pcszName, (f) ? "true" : "false");
}

/**
 * Private constructor for a new attribute node.
 *
 * @param   pElmRoot    Pointer to the root element.  Needed for getting the
 *                      default name space.
 * @param   pParent     Pointer to the parent element (always an ElementNode,
 *                      despite the type).  NULL for the root node.
 * @param   pListAnchor Pointer to the m_children member of the parent.  NULL
 *                      for the root node.
 * @param   pLibAttr    Pointer to the libxml2 attribute structure.
 */
AttributeNode::AttributeNode(const ElementNode *pElmRoot,
                             Node *pParent,
                             PRTLISTANCHOR pListAnchor,
                             xmlAttr *pLibAttr)
    : Node(IsAttribute,
           pParent,
           pListAnchor,
           NULL,
           pLibAttr)
{
    m_pcszName = (const char *)pLibAttr->name;
    RT_NOREF_PV(pElmRoot);

    if (   pLibAttr->ns
        && pLibAttr->ns->prefix)
    {
        m_pcszNamespacePrefix = (const char *)pLibAttr->ns->prefix;
        m_pcszNamespaceHref   = (const char *)pLibAttr->ns->href;
    }
}

ContentNode::ContentNode(Node *pParent, PRTLISTANCHOR pListAnchor, xmlNode *pLibNode)
    : Node(IsContent,
           pParent,
           pListAnchor,
           pLibNode,
           NULL)
{
}

/*
 * NodesLoop
 *
 */

struct NodesLoop::Data
{
    ElementNodesList listElements;
    ElementNodesList::const_iterator it;
};

NodesLoop::NodesLoop(const ElementNode &node, const char *pcszMatch /* = NULL */)
{
    m = new Data;
    node.getChildElements(m->listElements, pcszMatch);
    m->it = m->listElements.begin();
}

NodesLoop::~NodesLoop()
{
    delete m;
}


/**
 * Handy convenience helper for looping over all child elements. Create an
 * instance of NodesLoop on the stack and call this method until it returns
 * NULL, like this:
 * <code>
 *      xml::ElementNode node;               // should point to an element
 *      xml::NodesLoop loop(node, "child");  // find all "child" elements under node
 *      const xml::ElementNode *pChild = NULL;
 *      while (pChild = loop.forAllNodes())
 *          ...;
 * </code>
 * @return
 */
const ElementNode* NodesLoop::forAllNodes() const
{
    const ElementNode *pNode = NULL;

    if (m->it != m->listElements.end())
    {
        pNode = *(m->it);
        ++(m->it);
    }

    return pNode;
}

////////////////////////////////////////////////////////////////////////////////
//
// Document class
//
////////////////////////////////////////////////////////////////////////////////

struct Document::Data
{
    xmlDocPtr   plibDocument;
    ElementNode *pRootElement;
    ElementNode *pComment;

    Data()
    {
        plibDocument = NULL;
        pRootElement = NULL;
        pComment = NULL;
    }

    ~Data()
    {
        reset();
    }

    void reset()
    {
        if (plibDocument)
        {
            xmlFreeDoc(plibDocument);
            plibDocument = NULL;
        }
        if (pRootElement)
        {
            delete pRootElement;
            pRootElement = NULL;
        }
        if (pComment)
        {
            delete pComment;
            pComment = NULL;
        }
    }

    void copyFrom(const Document::Data *p)
    {
        if (p->plibDocument)
        {
            plibDocument = xmlCopyDoc(p->plibDocument,
                                      1);      // recursive == copy all
        }
    }
};

Document::Document()
    : m(new Data)
{
}

Document::Document(const Document &x)
    : m(new Data)
{
    m->copyFrom(x.m);
}

Document& Document::operator=(const Document &x)
{
    m->reset();
    m->copyFrom(x.m);
    return *this;
}

Document::~Document()
{
    delete m;
}

/**
 * private method to refresh all internal structures after the internal pDocument
 * has changed. Called from XmlFileParser::read(). m->reset() must have been
 * called before to make sure all members except the internal pDocument are clean.
 */
void Document::refreshInternals() // private
{
    m->pRootElement = new ElementNode(NULL, NULL, NULL, xmlDocGetRootElement(m->plibDocument));

    ElementNode::buildChildren(m->pRootElement);
}

/**
 * Returns the root element of the document, or NULL if the document is empty.
 * Const variant.
 * @return
 */
const ElementNode *Document::getRootElement() const
{
    return m->pRootElement;
}

/**
 * Returns the root element of the document, or NULL if the document is empty.
 * Non-const variant.
 * @return
 */
ElementNode *Document::getRootElement()
{
    return m->pRootElement;
}

/**
 * Creates a new element node and sets it as the root element.
 *
 * This will only work if the document is empty; otherwise EDocumentNotEmpty is
 * thrown.
 */
ElementNode *Document::createRootElement(const char *pcszRootElementName,
                                         const char *pcszComment /* = NULL */)
{
    if (m->pRootElement || m->plibDocument)
        throw EDocumentNotEmpty(RT_SRC_POS);

    // libxml side: create document, create root node
    m->plibDocument = xmlNewDoc((const xmlChar *)"1.0");
    xmlNode *plibRootNode = xmlNewNode(NULL /*namespace*/ , (const xmlChar *)pcszRootElementName);
    if (!plibRootNode)
        throw std::bad_alloc();
    xmlDocSetRootElement(m->plibDocument, plibRootNode);

    // now wrap this in C++
    m->pRootElement = new ElementNode(NULL, NULL, NULL, plibRootNode);

    // add document global comment if specified
    if (pcszComment != NULL)
    {
        xmlNode *pComment = xmlNewDocComment(m->plibDocument, (const xmlChar *)pcszComment);
        if (!pComment)
            throw std::bad_alloc();
        xmlAddPrevSibling(plibRootNode, pComment);

        // now wrap this in C++
        m->pComment = new ElementNode(NULL, NULL, NULL, pComment);
    }

    return m->pRootElement;
}

////////////////////////////////////////////////////////////////////////////////
//
// XmlParserBase class
//
////////////////////////////////////////////////////////////////////////////////

static void xmlParserBaseGenericError(void *pCtx, const char *pszMsg, ...) RT_NOTHROW_DEF
{
    NOREF(pCtx);
    va_list args;
    va_start(args, pszMsg);
    RTLogRelPrintfV(pszMsg, args);
    va_end(args);
}

static void xmlParserBaseStructuredError(void *pCtx, xmlErrorPtr error) RT_NOTHROW_DEF
{
    NOREF(pCtx);
    /* we expect that there is always a trailing NL */
    LogRel(("XML error at '%s' line %d: %s", error->file, error->line, error->message));
}

XmlParserBase::XmlParserBase()
{
    m_ctxt = xmlNewParserCtxt();
    if (m_ctxt == NULL)
        throw std::bad_alloc();
    /* per-thread so it must be here */
    xmlSetGenericErrorFunc(NULL, xmlParserBaseGenericError);
    xmlSetStructuredErrorFunc(NULL, xmlParserBaseStructuredError);
}

XmlParserBase::~XmlParserBase()
{
    xmlSetStructuredErrorFunc(NULL, NULL);
    xmlSetGenericErrorFunc(NULL, NULL);
    xmlFreeParserCtxt (m_ctxt);
    m_ctxt = NULL;
}

////////////////////////////////////////////////////////////////////////////////
//
// XmlMemParser class
//
////////////////////////////////////////////////////////////////////////////////

XmlMemParser::XmlMemParser()
    : XmlParserBase()
{
}

XmlMemParser::~XmlMemParser()
{
}

/**
 * Parse the given buffer and fills the given Document object with its contents.
 * Throws XmlError on parsing errors.
 *
 * The document that is passed in will be reset before being filled if not empty.
 *
 * @param pvBuf         Memory buffer to parse.
 * @param cbSize        Size of the memory buffer.
 * @param strFilename   Refernece to the name of the file we're parsing.
 * @param doc           Reference to the output document.  This will be reset
 *                      and filled with data according to file contents.
 */
void XmlMemParser::read(const void *pvBuf, size_t cbSize,
                        const RTCString &strFilename,
                        Document &doc)
{
    GlobalLock lock;
//     global.setExternalEntityLoader(ExternalEntityLoader);

    const char *pcszFilename = strFilename.c_str();

    doc.m->reset();
    const int options = XML_PARSE_NOBLANKS /* remove blank nodes */
                      | XML_PARSE_NONET    /* forbit any network access */
#if LIBXML_VERSION >= 20700
                      | XML_PARSE_HUGE     /* don't restrict the node depth
                                              to 256 (bad for snapshots!) */
#endif
                ;
    if (!(doc.m->plibDocument = xmlCtxtReadMemory(m_ctxt,
                                                  (const char*)pvBuf,
                                                  (int)cbSize,
                                                  pcszFilename,
                                                  NULL,       // encoding = auto
                                                  options)))
        throw XmlError(xmlCtxtGetLastError(m_ctxt));

    doc.refreshInternals();
}

////////////////////////////////////////////////////////////////////////////////
//
// XmlMemWriter class
//
////////////////////////////////////////////////////////////////////////////////

XmlMemWriter::XmlMemWriter()
  : m_pBuf(0)
{
}

XmlMemWriter::~XmlMemWriter()
{
    if (m_pBuf)
        xmlFree(m_pBuf);
}

void XmlMemWriter::write(const Document &doc, void **ppvBuf, size_t *pcbSize)
{
    if (m_pBuf)
    {
        xmlFree(m_pBuf);
        m_pBuf = 0;
    }
    int size;
    xmlDocDumpFormatMemory(doc.m->plibDocument, (xmlChar**)&m_pBuf, &size, 1);
    *ppvBuf = m_pBuf;
    *pcbSize = size;
}


////////////////////////////////////////////////////////////////////////////////
//
// XmlStringWriter class
//
////////////////////////////////////////////////////////////////////////////////

XmlStringWriter::XmlStringWriter()
  : m_pStrDst(NULL), m_fOutOfMemory(false)
{
}

int XmlStringWriter::write(const Document &rDoc, RTCString *pStrDst)
{
    /*
     * Clear the output string and take the global libxml2 lock so we can
     * safely configure the output formatting.
     */
    pStrDst->setNull();

    GlobalLock lock;

    xmlIndentTreeOutput = 1;
    xmlTreeIndentString = "  ";
    xmlSaveNoEmptyTags  = 0;

    /*
     * Do a pass to calculate the size.
     */
    size_t cbOutput = 1; /* zero term */

    xmlSaveCtxtPtr pSaveCtx= xmlSaveToIO(WriteCallbackForSize, CloseCallback, &cbOutput, NULL /*pszEncoding*/, XML_SAVE_FORMAT);
    if (!pSaveCtx)
        return VERR_NO_MEMORY;

    long rcXml = xmlSaveDoc(pSaveCtx, rDoc.m->plibDocument);
    xmlSaveClose(pSaveCtx);
    if (rcXml == -1)
        return VERR_GENERAL_FAILURE;

    /*
     * Try resize the string.
     */
    int rc = pStrDst->reserveNoThrow(cbOutput);
    if (RT_SUCCESS(rc))
    {
        /*
         * Do the real run where we feed output to the string.
         */
        m_pStrDst      = pStrDst;
        m_fOutOfMemory = false;
        pSaveCtx = xmlSaveToIO(WriteCallbackForReal, CloseCallback, this, NULL /*pszEncoding*/, XML_SAVE_FORMAT);
        if (pSaveCtx)
        {
            rcXml = xmlSaveDoc(pSaveCtx, rDoc.m->plibDocument);
            xmlSaveClose(pSaveCtx);
            m_pStrDst = NULL;
            if (rcXml != -1)
            {
                if (!m_fOutOfMemory)
                    return VINF_SUCCESS;

                rc = VERR_NO_STR_MEMORY;
            }
            else
                rc = VERR_GENERAL_FAILURE;
        }
        else
            rc = VERR_NO_MEMORY;
        pStrDst->setNull();
        m_pStrDst = NULL;
    }
    return rc;
}

/*static*/ int XmlStringWriter::WriteCallbackForSize(void *pvUser, const char *pachBuf, int cbToWrite) RT_NOTHROW_DEF
{
    if (cbToWrite > 0)
        *(size_t *)pvUser += (unsigned)cbToWrite;
    RT_NOREF(pachBuf);
    return cbToWrite;
}

/*static*/ int XmlStringWriter::WriteCallbackForReal(void *pvUser, const char *pachBuf, int cbToWrite) RT_NOTHROW_DEF
{
    XmlStringWriter *pThis = static_cast<XmlStringWriter*>(pvUser);
    if (!pThis->m_fOutOfMemory)
    {
        if (cbToWrite > 0)
        {
            try
            {
                pThis->m_pStrDst->append(pachBuf, (size_t)cbToWrite);
            }
            catch (std::bad_alloc &)
            {
                pThis->m_fOutOfMemory = true;
                return -1;
            }
        }
        return cbToWrite;
    }
    return -1; /* failure */
}

/*static*/ int XmlStringWriter::CloseCallback(void *pvUser) RT_NOTHROW_DEF
{
    /* Nothing to do here. */
    RT_NOREF(pvUser);
    return 0;
}



////////////////////////////////////////////////////////////////////////////////
//
// XmlFileParser class
//
////////////////////////////////////////////////////////////////////////////////

struct XmlFileParser::Data
{
    RTCString strXmlFilename;

    Data()
    {
    }

    ~Data()
    {
    }
};

XmlFileParser::XmlFileParser()
    : XmlParserBase(),
      m(new Data())
{
}

XmlFileParser::~XmlFileParser()
{
    delete m;
    m = NULL;
}

struct IOContext
{
    File file;
    RTCString error;

    IOContext(const char *pcszFilename, File::Mode mode, bool fFlush = false)
        : file(mode, pcszFilename, fFlush)
    {
    }

    void setError(const RTCError &x)
    {
        error = x.what();
    }

    void setError(const std::exception &x)
    {
        error = x.what();
    }

private:
    DECLARE_CLS_COPY_CTOR_ASSIGN_NOOP(IOContext); /* (shuts up C4626 and C4625 MSC warnings) */
};

struct ReadContext : IOContext
{
    ReadContext(const char *pcszFilename)
        : IOContext(pcszFilename, File::Mode_Read)
    {
    }

private:
    DECLARE_CLS_COPY_CTOR_ASSIGN_NOOP(ReadContext); /* (shuts up C4626 and C4625 MSC warnings) */
};

struct WriteContext : IOContext
{
    WriteContext(const char *pcszFilename, bool fFlush)
        : IOContext(pcszFilename, File::Mode_Overwrite, fFlush)
    {
    }

private:
    DECLARE_CLS_COPY_CTOR_ASSIGN_NOOP(WriteContext); /* (shuts up C4626 and C4625 MSC warnings) */
};

/**
 * Reads the given file and fills the given Document object with its contents.
 * Throws XmlError on parsing errors.
 *
 * The document that is passed in will be reset before being filled if not empty.
 *
 * @param strFilename in: name fo file to parse.
 * @param doc out: document to be reset and filled with data according to file contents.
 */
void XmlFileParser::read(const RTCString &strFilename,
                         Document &doc)
{
    GlobalLock lock;
//     global.setExternalEntityLoader(ExternalEntityLoader);

    m->strXmlFilename = strFilename;
    const char *pcszFilename = strFilename.c_str();

    ReadContext context(pcszFilename);
    doc.m->reset();
    const int options = XML_PARSE_NOBLANKS /* remove blank nodes */
                      | XML_PARSE_NONET    /* forbit any network access */
#if LIBXML_VERSION >= 20700
                      | XML_PARSE_HUGE     /* don't restrict the node depth
                                              to 256 (bad for snapshots!) */
#endif
                ;
    if (!(doc.m->plibDocument = xmlCtxtReadIO(m_ctxt,
                                              ReadCallback,
                                              CloseCallback,
                                              &context,
                                              pcszFilename,
                                              NULL,       // encoding = auto
                                              options)))
        throw XmlError(xmlCtxtGetLastError(m_ctxt));

    doc.refreshInternals();
}

/*static*/ int XmlFileParser::ReadCallback(void *aCtxt, char *aBuf, int aLen) RT_NOTHROW_DEF
{
    ReadContext *pContext = static_cast<ReadContext*>(aCtxt);

    /* To prevent throwing exceptions while inside libxml2 code, we catch
     * them and forward to our level using a couple of variables. */

    try
    {
        return pContext->file.read(aBuf, aLen);
    }
    catch (const xml::EIPRTFailure &err) { pContext->setError(err); }
    catch (const RTCError &err) { pContext->setError(err); }
    catch (const std::exception &err) { pContext->setError(err); }
    catch (...) { pContext->setError(xml::LogicError(RT_SRC_POS)); }

    return -1 /* failure */;
}

/*static*/ int XmlFileParser::CloseCallback(void *aCtxt) RT_NOTHROW_DEF
{
    /// @todo to be written
    NOREF(aCtxt);

    return -1;
}

////////////////////////////////////////////////////////////////////////////////
//
// XmlFileWriter class
//
////////////////////////////////////////////////////////////////////////////////

struct XmlFileWriter::Data
{
    Document *pDoc;
};

XmlFileWriter::XmlFileWriter(Document &doc)
{
    m = new Data();
    m->pDoc = &doc;
}

XmlFileWriter::~XmlFileWriter()
{
    delete m;
}

void XmlFileWriter::writeInternal(const char *pcszFilename, bool fSafe)
{
    WriteContext context(pcszFilename, fSafe);

    GlobalLock lock;

    /* serialize to the stream */
    xmlIndentTreeOutput = 1;
    xmlTreeIndentString = "  ";
    xmlSaveNoEmptyTags = 0;

    xmlSaveCtxtPtr saveCtxt;
    if (!(saveCtxt = xmlSaveToIO(WriteCallback,
                                 CloseCallback,
                                 &context,
                                 NULL,
                                 XML_SAVE_FORMAT)))
        throw xml::LogicError(RT_SRC_POS);

    long rc = xmlSaveDoc(saveCtxt, m->pDoc->m->plibDocument);
    if (rc == -1)
    {
        /* look if there was a forwarded exception from the lower level */
//         if (m->trappedErr.get() != NULL)
//             m->trappedErr->rethrow();

        /* there must be an exception from the Output implementation,
         * otherwise the save operation must always succeed. */
        throw xml::LogicError(RT_SRC_POS);
    }

    xmlSaveClose(saveCtxt);
}

void XmlFileWriter::write(const char *pcszFilename, bool fSafe)
{
    if (!fSafe)
        writeInternal(pcszFilename, fSafe);
    else
    {
        /* Empty string and directory spec must be avoid. */
        if (RTPathFilename(pcszFilename) == NULL)
            throw xml::LogicError(RT_SRC_POS);

        /* Construct both filenames first to ease error handling.  */
        char szTmpFilename[RTPATH_MAX];
        int rc = RTStrCopy(szTmpFilename, sizeof(szTmpFilename) - strlen(s_pszTmpSuff), pcszFilename);
        if (RT_FAILURE(rc))
            throw EIPRTFailure(rc, "RTStrCopy");
        strcat(szTmpFilename, s_pszTmpSuff);

        char szPrevFilename[RTPATH_MAX];
        rc = RTStrCopy(szPrevFilename, sizeof(szPrevFilename) - strlen(s_pszPrevSuff), pcszFilename);
        if (RT_FAILURE(rc))
            throw EIPRTFailure(rc, "RTStrCopy");
        strcat(szPrevFilename, s_pszPrevSuff);

        /* Write the XML document to the temporary file.  */
        writeInternal(szTmpFilename, fSafe);

        /* Make a backup of any existing file (ignore failure). */
        uint64_t cbPrevFile;
        rc = RTFileQuerySizeByPath(pcszFilename, &cbPrevFile);
        if (RT_SUCCESS(rc) && cbPrevFile >= 16)
            RTFileRename(pcszFilename, szPrevFilename, RTPATHRENAME_FLAGS_REPLACE);

        /* Commit the temporary file. Just leave the tmp file behind on failure. */
        rc = RTFileRename(szTmpFilename, pcszFilename, RTPATHRENAME_FLAGS_REPLACE);
        if (RT_FAILURE(rc))
            throw EIPRTFailure(rc, "Failed to replace '%s' with '%s'", pcszFilename, szTmpFilename);

        /* Flush the directory changes (required on linux at least). */
        RTPathStripFilename(szTmpFilename);
        rc = RTDirFlush(szTmpFilename);
        AssertMsg(RT_SUCCESS(rc) || rc == VERR_NOT_SUPPORTED || rc == VERR_NOT_IMPLEMENTED, ("%Rrc\n", rc));
    }
}

/*static*/ int XmlFileWriter::WriteCallback(void *aCtxt, const char *aBuf, int aLen) RT_NOTHROW_DEF
{
    WriteContext *pContext = static_cast<WriteContext*>(aCtxt);

    /* To prevent throwing exceptions while inside libxml2 code, we catch
     * them and forward to our level using a couple of variables. */
    try
    {
        return pContext->file.write(aBuf, aLen);
    }
    catch (const xml::EIPRTFailure &err) { pContext->setError(err); }
    catch (const RTCError &err) { pContext->setError(err); }
    catch (const std::exception &err) { pContext->setError(err); }
    catch (...) { pContext->setError(xml::LogicError(RT_SRC_POS)); }

    return -1 /* failure */;
}

/*static*/ int XmlFileWriter::CloseCallback(void *aCtxt) RT_NOTHROW_DEF
{
    /// @todo to be written
    NOREF(aCtxt);

    return -1;
}

/*static*/ const char * const XmlFileWriter::s_pszTmpSuff  = "-tmp";
/*static*/ const char * const XmlFileWriter::s_pszPrevSuff = "-prev";


} // end namespace xml