summaryrefslogtreecommitdiff
path: root/convert.c
blob: 6261921cfb7728e23f78bb7d340583b52300d638 (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
#include "cache.h"
#include "config.h"
#include "object-store.h"
#include "attr.h"
#include "run-command.h"
#include "quote.h"
#include "sigchain.h"
#include "pkt-line.h"
#include "sub-process.h"
#include "utf8.h"
#include "ll-merge.h"
 
/*
 * convert.c - convert a file when checking it out and checking it in.
 *
 * This should use the pathname to decide on whether it wants to do some
 * more interesting conversions (automatic gzip/unzip, general format
 * conversions etc etc), but by default it just does automatic CRLF<->LF
 * translation when the "text" attribute or "auto_crlf" option is set.
 */
 
/* Stat bits: When BIN is set, the txt bits are unset */
#define CONVERT_STAT_BITS_TXT_LF    0x1
#define CONVERT_STAT_BITS_TXT_CRLF  0x2
#define CONVERT_STAT_BITS_BIN       0x4
 
enum crlf_action {
	CRLF_UNDEFINED,
	CRLF_BINARY,
	CRLF_TEXT,
	CRLF_TEXT_INPUT,
	CRLF_TEXT_CRLF,
	CRLF_AUTO,
	CRLF_AUTO_INPUT,
	CRLF_AUTO_CRLF
};
 
struct text_stat {
	/* NUL, CR, LF and CRLF counts */
	unsigned nul, lonecr, lonelf, crlf;
 
	/* These are just approximations! */
	unsigned printable, nonprintable;
};
 
static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
{
	unsigned long i;
 
	memset(stats, 0, sizeof(*stats));
 
	for (i = 0; i < size; i++) {
		unsigned char c = buf[i];
		if (c == '\r') {
			if (i+1 < size && buf[i+1] == '\n') {
				stats->crlf++;
				i++;
			} else
				stats->lonecr++;
			continue;
		}
		if (c == '\n') {
			stats->lonelf++;
			continue;
		}
		if (c == 127)
			/* DEL */
			stats->nonprintable++;
		else if (c < 32) {
			switch (c) {
				/* BS, HT, ESC and FF */
			case '\b': case '\t': case '\033': case '\014':
				stats->printable++;
				break;
			case 0:
				stats->nul++;
				/* fall through */
			default:
				stats->nonprintable++;
			}
		}
		else
			stats->printable++;
	}
 
	/* If file ends with EOF then don't count this EOF as non-printable. */
	if (size >= 1 && buf[size-1] == '\032')
		stats->nonprintable--;
}
 
/*
 * The same heuristics as diff.c::mmfile_is_binary()
 * We treat files with bare CR as binary
 */
static int convert_is_binary(const struct text_stat *stats)
{
	if (stats->lonecr)
		return 1;
	if (stats->nul)
		return 1;
	if ((stats->printable >> 7) < stats->nonprintable)
		return 1;
	return 0;
}
 
static unsigned int gather_convert_stats(const char *data, unsigned long size)
{
	struct text_stat stats;
	int ret = 0;
	if (!data || !size)
		return 0;
	gather_stats(data, size, &stats);
	if (convert_is_binary(&stats))
		ret |= CONVERT_STAT_BITS_BIN;
	if (stats.crlf)
		ret |= CONVERT_STAT_BITS_TXT_CRLF;
	if (stats.lonelf)
		ret |=  CONVERT_STAT_BITS_TXT_LF;
 
	return ret;
}
 
static const char *gather_convert_stats_ascii(const char *data, unsigned long size)
{
	unsigned int convert_stats = gather_convert_stats(data, size);
 
	if (convert_stats & CONVERT_STAT_BITS_BIN)
		return "-text";
	switch (convert_stats) {
	case CONVERT_STAT_BITS_TXT_LF:
		return "lf";
	case CONVERT_STAT_BITS_TXT_CRLF:
		return "crlf";
	case CONVERT_STAT_BITS_TXT_LF | CONVERT_STAT_BITS_TXT_CRLF:
		return "mixed";
	default:
		return "none";
	}
}
 
const char *get_cached_convert_stats_ascii(const struct index_state *istate,
					   const char *path)
{
	const char *ret;
	unsigned long sz;
	void *data = read_blob_data_from_index(istate, path, &sz);
	ret = gather_convert_stats_ascii(data, sz);
	free(data);
	return ret;
}
 
const char *get_wt_convert_stats_ascii(const char *path)
{
	const char *ret = "";
	struct strbuf sb = STRBUF_INIT;
	if (strbuf_read_file(&sb, path, 0) >= 0)
		ret = gather_convert_stats_ascii(sb.buf, sb.len);
	strbuf_release(&sb);
	return ret;
}
 
static int text_eol_is_crlf(void)
{
	if (auto_crlf == AUTO_CRLF_TRUE)
		return 1;
	else if (auto_crlf == AUTO_CRLF_INPUT)
		return 0;
	if (core_eol == EOL_CRLF)
		return 1;
	if (core_eol == EOL_UNSET && EOL_NATIVE == EOL_CRLF)
		return 1;
	return 0;
}
 
static enum eol output_eol(enum crlf_action crlf_action)
{
	switch (crlf_action) {
	case CRLF_BINARY:
		return EOL_UNSET;
	case CRLF_TEXT_CRLF:
		return EOL_CRLF;
	case CRLF_TEXT_INPUT:
		return EOL_LF;
	case CRLF_UNDEFINED:
	case CRLF_AUTO_CRLF:
		return EOL_CRLF;
	case CRLF_AUTO_INPUT:
		return EOL_LF;
	case CRLF_TEXT:
	case CRLF_AUTO:
		/* fall through */
		return text_eol_is_crlf() ? EOL_CRLF : EOL_LF;
	}
	warning(_("illegal crlf_action %d"), (int)crlf_action);
	return core_eol;
}
 
static void check_global_conv_flags_eol(const char *path, enum crlf_action crlf_action,
			    struct text_stat *old_stats, struct text_stat *new_stats,
			    int conv_flags)
{
	if (old_stats->crlf && !new_stats->crlf ) {
		/*
		 * CRLFs would not be restored by checkout
		 */
		if (conv_flags & CONV_EOL_RNDTRP_DIE)
			die(_("CRLF would be replaced by LF in %s"), path);
		else if (conv_flags & CONV_EOL_RNDTRP_WARN)
			warning(_("CRLF will be replaced by LF in %s.\n"
				  "The file will have its original line"
				  " endings in your working directory"), path);
	} else if (old_stats->lonelf && !new_stats->lonelf ) {
		/*
		 * CRLFs would be added by checkout
		 */
		if (conv_flags & CONV_EOL_RNDTRP_DIE)
			die(_("LF would be replaced by CRLF in %s"), path);
		else if (conv_flags & CONV_EOL_RNDTRP_WARN)
			warning(_("LF will be replaced by CRLF in %s.\n"
				  "The file will have its original line"
				  " endings in your working directory"), path);
	}
}
 
static int has_crlf_in_index(const struct index_state *istate, const char *path)
{
	unsigned long sz;
	void *data;
	const char *crp;
	int has_crlf = 0;
 
	data = read_blob_data_from_index(istate, path, &sz);
	if (!data)
		return 0;
 
	crp = memchr(data, '\r', sz);
	if (crp) {
		unsigned int ret_stats;
		ret_stats = gather_convert_stats(data, sz);
		if (!(ret_stats & CONVERT_STAT_BITS_BIN) &&
		    (ret_stats & CONVERT_STAT_BITS_TXT_CRLF))
			has_crlf = 1;
	}
	free(data);
	return has_crlf;
}
 
static int will_convert_lf_to_crlf(struct text_stat *stats,
				   enum crlf_action crlf_action)
{
	if (output_eol(crlf_action) != EOL_CRLF)
		return 0;
	/* No "naked" LF? Nothing to convert, regardless. */
	if (!stats->lonelf)
		return 0;
 
	if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
		/* If we have any CR or CRLF line endings, we do not touch it */
		/* This is the new safer autocrlf-handling */
		if (stats->lonecr || stats->crlf)
			return 0;
 
		if (convert_is_binary(stats))
			return 0;
	}
	return 1;
 
}
 
static int validate_encoding(const char *path, const char *enc,
		      const char *data, size_t len, int die_on_error)
{
	const char *stripped;
 
	/* We only check for UTF here as UTF?? can be an alias for UTF-?? */
	if (skip_iprefix(enc, "UTF", &stripped)) {
		skip_prefix(stripped, "-", &stripped);
 
		/*
		 * Check for detectable errors in UTF encodings
		 */
		if (has_prohibited_utf_bom(enc, data, len)) {
			const char *error_msg = _(
				"BOM is prohibited in '%s' if encoded as %s");
			/*
			 * This advice is shown for UTF-??BE and UTF-??LE encodings.
			 * We cut off the last two characters of the encoding name
			 * to generate the encoding name suitable for BOMs.
			 */
			const char *advise_msg = _(
				"The file '%s' contains a byte order "
				"mark (BOM). Please use UTF-%.*s as "
				"working-tree-encoding.");
			int stripped_len = strlen(stripped) - strlen("BE");
			advise(advise_msg, path, stripped_len, stripped);
			if (die_on_error)
				die(error_msg, path, enc);
			else {
				return error(error_msg, path, enc);
			}
 
		} else if (is_missing_required_utf_bom(enc, data, len)) {
			const char *error_msg = _(
				"BOM is required in '%s' if encoded as %s");
			const char *advise_msg = _(
				"The file '%s' is missing a byte order "
				"mark (BOM). Please use UTF-%sBE or UTF-%sLE "
				"(depending on the byte order) as "
				"working-tree-encoding.");
			advise(advise_msg, path, stripped, stripped);
			if (die_on_error)
				die(error_msg, path, enc);
			else {
				return error(error_msg, path, enc);
			}
		}
 
	}
	return 0;
}
 
static void trace_encoding(const char *context, const char *path,
			   const char *encoding, const char *buf, size_t len)
{
	static struct trace_key coe = TRACE_KEY_INIT(WORKING_TREE_ENCODING);
	struct strbuf trace = STRBUF_INIT;
	int i;
 
	strbuf_addf(&trace, "%s (%s, considered %s):\n", context, path, encoding);
	for (i = 0; i < len && buf; ++i) {
		strbuf_addf(
			&trace, "| \033[2m%2i:\033[0m %2x \033[2m%c\033[0m%c",
			i,
			(unsigned char) buf[i],
			(buf[i] > 32 && buf[i] < 127 ? buf[i] : ' '),
			((i+1) % 8 && (i+1) < len ? ' ' : '\n')
		);
	}
	strbuf_addchars(&trace, '\n', 1);
 
	trace_strbuf(&coe, &trace);
	strbuf_release(&trace);
}
 
static int check_roundtrip(const char *enc_name)
{
	/*
	 * check_roundtrip_encoding contains a string of comma and/or
	 * space separated encodings (eg. "UTF-16, ASCII, CP1125").
	 * Search for the given encoding in that string.
	 */
	const char *found = strcasestr(check_roundtrip_encoding, enc_name);
	const char *next;
	int len;
	if (!found)
		return 0;
	next = found + strlen(enc_name);
	len = strlen(check_roundtrip_encoding);
	return (found && (
			/*
			 * check that the found encoding is at the
			 * beginning of check_roundtrip_encoding or
			 * that it is prefixed with a space or comma
			 */
			found == check_roundtrip_encoding || (
				(isspace(found[-1]) || found[-1] == ',')
			)
		) && (
			/*
			 * check that the found encoding is at the
			 * end of check_roundtrip_encoding or
			 * that it is suffixed with a space or comma
			 */
			next == check_roundtrip_encoding + len || (
				next < check_roundtrip_encoding + len &&
				(isspace(next[0]) || next[0] == ',')
			)
		));
}
 
static const char *default_encoding = "UTF-8";
 
static int encode_to_git(const char *path, const char *src, size_t src_len,
			 struct strbuf *buf, const char *enc, int conv_flags)
{
	char *dst;
	size_t dst_len;
	int die_on_error = conv_flags & CONV_WRITE_OBJECT;
 
	/*
	 * No encoding is specified or there is nothing to encode.
	 * Tell the caller that the content was not modified.
	 */
	if (!enc || (src && !src_len))
		return 0;
 
	/*
	 * Looks like we got called from "would_convert_to_git()".
	 * This means Git wants to know if it would encode (= modify!)
	 * the content. Let's answer with "yes", since an encoding was
	 * specified.
	 */
	if (!buf && !src)
		return 1;
 
	if (validate_encoding(path, enc, src, src_len, die_on_error))
		return 0;
 
	trace_encoding("source", path, enc, src, src_len);
	dst = reencode_string_len(src, src_len, default_encoding, enc,
				  &dst_len);
	if (!dst) {
		/*
		 * We could add the blob "as-is" to Git. However, on checkout
		 * we would try to re-encode to the original encoding. This
		 * would fail and we would leave the user with a messed-up
		 * working tree. Let's try to avoid this by screaming loud.
		 */
		const char* msg = _("failed to encode '%s' from %s to %s");
		if (die_on_error)
			die(msg, path, enc, default_encoding);
		else {
			error(msg, path, enc, default_encoding);
			return 0;
		}
	}
	trace_encoding("destination", path, default_encoding, dst, dst_len);
 
	/*
	 * UTF supports lossless conversion round tripping [1] and conversions
	 * between UTF and other encodings are mostly round trip safe as
	 * Unicode aims to be a superset of all other character encodings.
	 * However, certain encodings (e.g. SHIFT-JIS) are known to have round
	 * trip issues [2]. Check the round trip conversion for all encodings
	 * listed in core.checkRoundtripEncoding.
	 *
	 * The round trip check is only performed if content is written to Git.
	 * This ensures that no information is lost during conversion to/from
	 * the internal UTF-8 representation.
	 *
	 * Please note, the code below is not tested because I was not able to
	 * generate a faulty round trip without an iconv error. Iconv errors
	 * are already caught above.
	 *
	 * [1] http://unicode.org/faq/utf_bom.html#gen2
	 * [2] https://support.microsoft.com/en-us/help/170559/prb-conversion-problem-between-shift-jis-and-unicode
	 */
	if (die_on_error && check_roundtrip(enc)) {
		char *re_src;
		size_t re_src_len;
 
		re_src = reencode_string_len(dst, dst_len,
					     enc, default_encoding,
					     &re_src_len);
 
		trace_printf("Checking roundtrip encoding for %s...\n", enc);
		trace_encoding("reencoded source", path, enc,
			       re_src, re_src_len);
 
		if (!re_src || src_len != re_src_len ||
		    memcmp(src, re_src, src_len)) {
			const char* msg = _("encoding '%s' from %s to %s and "
					    "back is not the same");
			die(msg, path, enc, default_encoding);
		}
 
		free(re_src);
	}
 
	strbuf_attach(buf, dst, dst_len, dst_len + 1);
	return 1;
}
 
static int encode_to_worktree(const char *path, const char *src, size_t src_len,
			      struct strbuf *buf, const char *enc)
{
	char *dst;
	size_t dst_len;
 
	/*
	 * No encoding is specified or there is nothing to encode.
	 * Tell the caller that the content was not modified.
	 */
	if (!enc || (src && !src_len))
		return 0;
 
	dst = reencode_string_len(src, src_len, enc, default_encoding,
				  &dst_len);
	if (!dst) {
		error(_("failed to encode '%s' from %s to %s"),
		      path, default_encoding, enc);
		return 0;
	}
 
	strbuf_attach(buf, dst, dst_len, dst_len + 1);
	return 1;
}
 
static int crlf_to_git(const struct index_state *istate,
		       const char *path, const char *src, size_t len,
		       struct strbuf *buf,
		       enum crlf_action crlf_action, int conv_flags)
{
	struct text_stat stats;
	char *dst;
	int convert_crlf_into_lf;
 
	if (crlf_action == CRLF_BINARY ||
	    (src && !len))
		return 0;
 
	/*
	 * If we are doing a dry-run and have no source buffer, there is
	 * nothing to analyze; we must assume we would convert.
	 */
	if (!buf && !src)
		return 1;
 
	gather_stats(src, len, &stats);
	/* Optimization: No CRLF? Nothing to convert, regardless. */
	convert_crlf_into_lf = !!stats.crlf;
 
	if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
		if (convert_is_binary(&stats))
			return 0;
		/*
		 * If the file in the index has any CR in it, do not
		 * convert.  This is the new safer autocrlf handling,
		 * unless we want to renormalize in a merge or
		 * cherry-pick.
		 */
		if ((!(conv_flags & CONV_EOL_RENORMALIZE)) &&
		    has_crlf_in_index(istate, path))
			convert_crlf_into_lf = 0;
	}
	if (((conv_flags & CONV_EOL_RNDTRP_WARN) ||
	     ((conv_flags & CONV_EOL_RNDTRP_DIE) && len))) {
		struct text_stat new_stats;
		memcpy(&new_stats, &stats, sizeof(new_stats));
		/* simulate "git add" */
		if (convert_crlf_into_lf) {
			new_stats.lonelf += new_stats.crlf;
			new_stats.crlf = 0;
		}
		/* simulate "git checkout" */
		if (will_convert_lf_to_crlf(&new_stats, crlf_action)) {
			new_stats.crlf += new_stats.lonelf;
			new_stats.lonelf = 0;
		}
		check_global_conv_flags_eol(path, crlf_action, &stats, &new_stats, conv_flags);
	}
	if (!convert_crlf_into_lf)
		return 0;
 
	/*
	 * At this point all of our source analysis is done, and we are sure we
	 * would convert. If we are in dry-run mode, we can give an answer.
	 */
	if (!buf)
		return 1;
 
	/* only grow if not in place */
	if (strbuf_avail(buf) + buf->len < len)
		strbuf_grow(buf, len - buf->len);
	dst = buf->buf;
	if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
		/*
		 * If we guessed, we already know we rejected a file with
		 * lone CR, and we can strip a CR without looking at what
		 * follow it.
		 */
		do {
			unsigned char c = *src++;
			if (c != '\r')
				*dst++ = c;
		} while (--len);
	} else {
		do {
			unsigned char c = *src++;
			if (! (c == '\r' && (1 < len && *src == '\n')))
				*dst++ = c;
		} while (--len);
	}
	strbuf_setlen(buf, dst - buf->buf);
	return 1;
}
 
static int crlf_to_worktree(const char *src, size_t len,
			    struct strbuf *buf, enum crlf_action crlf_action)
{
	char *to_free = NULL;
	struct text_stat stats;
 
	if (!len || output_eol(crlf_action) != EOL_CRLF)
		return 0;
 
	gather_stats(src, len, &stats);
	if (!will_convert_lf_to_crlf(&stats, crlf_action))
		return 0;
 
	/* are we "faking" in place editing ? */
	if (src == buf->buf)
		to_free = strbuf_detach(buf, NULL);
 
	strbuf_grow(buf, len + stats.lonelf);
	for (;;) {
		const char *nl = memchr(src, '\n', len);
		if (!nl)
			break;
		if (nl > src && nl[-1] == '\r') {
			strbuf_add(buf, src, nl + 1 - src);
		} else {
			strbuf_add(buf, src, nl - src);
			strbuf_addstr(buf, "\r\n");
		}
		len -= nl + 1 - src;
		src  = nl + 1;
	}
	strbuf_add(buf, src, len);
 
	free(to_free);
	return 1;
}
 
struct filter_params {
	const char *src;
	unsigned long size;
	int fd;
	const char *cmd;
	const char *path;
};
 
static int filter_buffer_or_fd(int in, int out, void *data)
{
	/*
	 * Spawn cmd and feed the buffer contents through its stdin.
	 */
	struct child_process child_process = CHILD_PROCESS_INIT;
	struct filter_params *params = (struct filter_params *)data;
	int write_err, status;
	const char *argv[] = { NULL, NULL };
 
	/* apply % substitution to cmd */
	struct strbuf cmd = STRBUF_INIT;
	struct strbuf path = STRBUF_INIT;
	struct strbuf_expand_dict_entry dict[] = {
		{ "f", NULL, },
		{ NULL, NULL, },
	};
 
	/* quote the path to preserve spaces, etc. */
	sq_quote_buf(&path, params->path);
	dict[0].value = path.buf;
 
	/* expand all %f with the quoted path */
	strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
	strbuf_release(&path);
 
	argv[0] = cmd.buf;
 
	child_process.argv = argv;
	child_process.use_shell = 1;
	child_process.in = -1;
	child_process.out = out;
 
	if (start_command(&child_process)) {
		strbuf_release(&cmd);
		return error(_("cannot fork to run external filter '%s'"),
			     params->cmd);
	}
 
	sigchain_push(SIGPIPE, SIG_IGN);
 
	if (params->src) {
		write_err = (write_in_full(child_process.in,
					   params->src, params->size) < 0);
		if (errno == EPIPE)
			write_err = 0;
	} else {
		write_err = copy_fd(params->fd, child_process.in);
		if (write_err == COPY_WRITE_ERROR && errno == EPIPE)
			write_err = 0;
	}
 
	if (close(child_process.in))
		write_err = 1;
	if (write_err)
		error(_("cannot feed the input to external filter '%s'"),
		      params->cmd);
 
	sigchain_pop(SIGPIPE);
 
	status = finish_command(&child_process);
	if (status)
		error(_("external filter '%s' failed %d"), params->cmd, status);
 
	strbuf_release(&cmd);
	return (write_err || status);
}
 
static int apply_single_file_filter(const char *path, const char *src, size_t len, int fd,
				    struct strbuf *dst, const char *cmd)
{
	/*
	 * Create a pipeline to have the command filter the buffer's
	 * contents.
	 *
	 * (child --> cmd) --> us
	 */
	int err = 0;
	struct strbuf nbuf = STRBUF_INIT;
	struct async async;
	struct filter_params params;
 
	memset(&async, 0, sizeof(async));
	async.proc = filter_buffer_or_fd;
	async.data = &params;
	async.out = -1;
	params.src = src;
	params.size = len;
	params.fd = fd;
	params.cmd = cmd;
	params.path = path;
 
	fflush(NULL);
	if (start_async(&async))
		return 0;	/* error was already reported */
 
	if (strbuf_read(&nbuf, async.out, 0) < 0) {
		err = error(_("read from external filter '%s' failed"), cmd);
	}
	if (close(async.out)) {
		err = error(_("read from external filter '%s' failed"), cmd);
	}
	if (finish_async(&async)) {
		err = error(_("external filter '%s' failed"), cmd);
	}
 
	if (!err) {
		strbuf_swap(dst, &nbuf);
	}
	strbuf_release(&nbuf);
	return !err;
}
 
#define CAP_CLEAN    (1u<<0)
#define CAP_SMUDGE   (1u<<1)
#define CAP_DELAY    (1u<<2)
 
struct cmd2process {
	struct subprocess_entry subprocess; /* must be the first member! */
	unsigned int supported_capabilities;
};
 
static int subprocess_map_initialized;
static struct hashmap subprocess_map;
 
static int start_multi_file_filter_fn(struct subprocess_entry *subprocess)
{
	static int versions[] = {2, 0};
	static struct subprocess_capability capabilities[] = {
		{ "clean",  CAP_CLEAN  },
		{ "smudge", CAP_SMUDGE },
		{ "delay",  CAP_DELAY  },
		{ NULL, 0 }
	};
	struct cmd2process *entry = (struct cmd2process *)subprocess;
	return subprocess_handshake(subprocess, "git-filter", versions, NULL,
				    capabilities,
				    &entry->supported_capabilities);
}
 
static void handle_filter_error(const struct strbuf *filter_status,
				struct cmd2process *entry,
				const unsigned int wanted_capability)
{
	if (!strcmp(filter_status->buf, "error"))
		; /* The filter signaled a problem with the file. */
	else if (!strcmp(filter_status->buf, "abort") && wanted_capability) {
		/*
		 * The filter signaled a permanent problem. Don't try to filter
		 * files with the same command for the lifetime of the current
		 * Git process.
		 */
		 entry->supported_capabilities &= ~wanted_capability;
	} else {
		/*
		 * Something went wrong with the protocol filter.
		 * Force shutdown and restart if another blob requires filtering.
		 */
		error(_("external filter '%s' failed"), entry->subprocess.cmd);
		subprocess_stop(&subprocess_map, &entry->subprocess);
		free(entry);
	}
}
 
static int apply_multi_file_filter(const char *path, const char *src, size_t len,
				   int fd, struct strbuf *dst, const char *cmd,
				   const unsigned int wanted_capability,
				   const struct checkout_metadata *meta,
				   struct delayed_checkout *dco)
{
	int err;
	int can_delay = 0;
	struct cmd2process *entry;
	struct child_process *process;
	struct strbuf nbuf = STRBUF_INIT;
	struct strbuf filter_status = STRBUF_INIT;
	const char *filter_type;
 
	if (!subprocess_map_initialized) {
		subprocess_map_initialized = 1;
		hashmap_init(&subprocess_map, cmd2process_cmp, NULL, 0);
		entry = NULL;
	} else {
		entry = (struct cmd2process *)subprocess_find_entry(&subprocess_map, cmd);
	}
 
	fflush(NULL);
 
	if (!entry) {
		entry = xmalloc(sizeof(*entry));
		entry->supported_capabilities = 0;
 
		if (subprocess_start(&subprocess_map, &entry->subprocess, cmd, start_multi_file_filter_fn)) {
			free(entry);
			return 0;
		}
	}
	process = &entry->subprocess.process;
 
	if (!(entry->supported_capabilities & wanted_capability))
		return 0;
 
	if (wanted_capability & CAP_CLEAN)
		filter_type = "clean";
	else if (wanted_capability & CAP_SMUDGE)
		filter_type = "smudge";
	else
		die(_("unexpected filter type"));
 
	sigchain_push(SIGPIPE, SIG_IGN);
 
	assert(strlen(filter_type) < LARGE_PACKET_DATA_MAX - strlen("command=\n"));
	err = packet_write_fmt_gently(process->in, "command=%s\n", filter_type);
	if (err)
		goto done;
 
	err = strlen(path) > LARGE_PACKET_DATA_MAX - strlen("pathname=\n");
	if (err) {
		error(_("path name too long for external filter"));
		goto done;
	}
 
	err = packet_write_fmt_gently(process->in, "pathname=%s\n", path);
	if (err)
		goto done;
 
	if (meta && meta->refname) {
		err = packet_write_fmt_gently(process->in, "ref=%s\n", meta->refname);
		if (err)
			goto done;
	}
 
	if (meta && !is_null_oid(&meta->treeish)) {
		err = packet_write_fmt_gently(process->in, "treeish=%s\n", oid_to_hex(&meta->treeish));
		if (err)
			goto done;
	}
 
	if (meta && !is_null_oid(&meta->blob)) {
		err = packet_write_fmt_gently(process->in, "blob=%s\n", oid_to_hex(&meta->blob));
		if (err)
			goto done;
	}
 
	if ((entry->supported_capabilities & CAP_DELAY) &&
	    dco && dco->state == CE_CAN_DELAY) {
		can_delay = 1;
		err = packet_write_fmt_gently(process->in, "can-delay=1\n");
		if (err)
			goto done;
	}
 
	err = packet_flush_gently(process->in);
	if (err)
		goto done;
 
	if (fd >= 0)
		err = write_packetized_from_fd(fd, process->in);
	else
		err = write_packetized_from_buf(src, len, process->in);
	if (err)
		goto done;
 
	err = subprocess_read_status(process->out, &filter_status);
	if (err)
		goto done;
 
	if (can_delay && !strcmp(filter_status.buf, "delayed")) {
		string_list_insert(&dco->filters, cmd);
		string_list_insert(&dco->paths, path);
	} else {
		/* The filter got the blob and wants to send us a response. */
		err = strcmp(filter_status.buf, "success");
		if (err)
			goto done;
 
		err = read_packetized_to_strbuf(process->out, &nbuf) < 0;
		if (err)
			goto done;
 
		err = subprocess_read_status(process->out, &filter_status);
		if (err)
			goto done;
 
		err = strcmp(filter_status.buf, "success");
	}
 
done:
	sigchain_pop(SIGPIPE);
 
	if (err)
		handle_filter_error(&filter_status, entry, wanted_capability);
	else
		strbuf_swap(dst, &nbuf);
	strbuf_release(&nbuf);
	return !err;
}
 
 
int async_query_available_blobs(const char *cmd, struct string_list *available_paths)
{
	int err;
	char *line;
	struct cmd2process *entry;
	struct child_process *process;
	struct strbuf filter_status = STRBUF_INIT;
 
	assert(subprocess_map_initialized);
	entry = (struct cmd2process *)subprocess_find_entry(&subprocess_map, cmd);
	if (!entry) {
		error(_("external filter '%s' is not available anymore although "
			"not all paths have been filtered"), cmd);
		return 0;
	}
	process = &entry->subprocess.process;
	sigchain_push(SIGPIPE, SIG_IGN);
 
	err = packet_write_fmt_gently(
		process->in, "command=list_available_blobs\n");
	if (err)
		goto done;
 
	err = packet_flush_gently(process->in);
	if (err)
		goto done;
 
	while ((line = packet_read_line(process->out, NULL))) {
		const char *path;
		if (skip_prefix(line, "pathname=", &path))
			string_list_insert(available_paths, xstrdup(path));
		else
			; /* ignore unknown keys */
	}
 
	err = subprocess_read_status(process->out, &filter_status);
	if (err)
		goto done;
 
	err = strcmp(filter_status.buf, "success");
 
done:
	sigchain_pop(SIGPIPE);
 
	if (err)
		handle_filter_error(&filter_status, entry, 0);
	return !err;
}
 
static struct convert_driver {
	const char *name;
	struct convert_driver *next;
	const char *smudge;
	const char *clean;
	const char *process;
	int required;
} *user_convert, **user_convert_tail;
 
static int apply_filter(const char *path, const char *src, size_t len,
			int fd, struct strbuf *dst, struct convert_driver *drv,
			const unsigned int wanted_capability,
			const struct checkout_metadata *meta,
			struct delayed_checkout *dco)
{
	const char *cmd = NULL;
 
	if (!drv)
		return 0;
 
	if (!dst)
		return 1;
 
	if ((wanted_capability & CAP_CLEAN) && !drv->process && drv->clean)
		cmd = drv->clean;
	else if ((wanted_capability & CAP_SMUDGE) && !drv->process && drv->smudge)
		cmd = drv->smudge;
 
	if (cmd && *cmd)
		return apply_single_file_filter(path, src, len, fd, dst, cmd);
	else if (drv->process && *drv->process)
		return apply_multi_file_filter(path, src, len, fd, dst,
			drv->process, wanted_capability, meta, dco);
 
	return 0;
}
 
static int read_convert_config(const char *var, const char *value, void *cb)
{
	const char *key, *name;
	int namelen;
	struct convert_driver *drv;
 
	/*
	 * External conversion drivers are configured using
	 * "filter.<name>.variable".
	 */
	if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
		return 0;
	for (drv = user_convert; drv; drv = drv->next)
		if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
			break;
	if (!drv) {
		drv = xcalloc(1, sizeof(struct convert_driver));
		drv->name = xmemdupz(name, namelen);
		*user_convert_tail = drv;
		user_convert_tail = &(drv->next);
	}
 
	/*
	 * filter.<name>.smudge and filter.<name>.clean specifies
	 * the command line:
	 *
	 *	command-line
	 *
	 * The command-line will not be interpolated in any way.
	 */
 
	if (!strcmp("smudge", key))
		return git_config_string(&drv->smudge, var, value);
 
	if (!strcmp("clean", key))
		return git_config_string(&drv->clean, var, value);
 
	if (!strcmp("process", key))
		return git_config_string(&drv->process, var, value);
 
	if (!strcmp("required", key)) {
		drv->required = git_config_bool(var, value);
		return 0;
	}
 
	return 0;
}
 
static int count_ident(const char *cp, unsigned long size)
{
	/*
	 * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
	 */
	int cnt = 0;
	char ch;
 
	while (size) {
		ch = *cp++;
		size--;
		if (ch != '$')
			continue;
		if (size < 3)
			break;
		if (memcmp("Id", cp, 2))
			continue;
		ch = cp[2];
		cp += 3;
		size -= 3;
		if (ch == '$')
			cnt++; /* $Id$ */
		if (ch != ':')
			continue;
 
		/*
		 * "$Id: ... "; scan up to the closing dollar sign and discard.
		 */
		while (size) {
			ch = *cp++;
			size--;
			if (ch == '$') {
				cnt++;
				break;
			}
			if (ch == '\n')
				break;
		}
	}
	return cnt;
}
 
static int ident_to_git(const char *src, size_t len,
			struct strbuf *buf, int ident)
{
	char *dst, *dollar;
 
	if (!ident || (src && !count_ident(src, len)))
		return 0;
 
	if (!buf)
		return 1;
 
	/* only grow if not in place */
	if (strbuf_avail(buf) + buf->len < len)
		strbuf_grow(buf, len - buf->len);
	dst = buf->buf;
	for (;;) {
		dollar = memchr(src, '$', len);
		if (!dollar)
			break;
		memmove(dst, src, dollar + 1 - src);
		dst += dollar + 1 - src;
		len -= dollar + 1 - src;
		src  = dollar + 1;
 
		if (len > 3 && !memcmp(src, "Id:", 3)) {
			dollar = memchr(src + 3, '$', len - 3);
			if (!dollar)
				break;
			if (memchr(src + 3, '\n', dollar - src - 3)) {
				/* Line break before the next dollar. */
				continue;
			}
 
			memcpy(dst, "Id$", 3);
			dst += 3;
			len -= dollar + 1 - src;
			src  = dollar + 1;
		}
	}
	memmove(dst, src, len);
	strbuf_setlen(buf, dst + len - buf->buf);
	return 1;
}
 
static int ident_to_worktree(const char *src, size_t len,
			     struct strbuf *buf, int ident)
{
	struct object_id oid;
	char *to_free = NULL, *dollar, *spc;
	int cnt;
 
	if (!ident)
		return 0;
 
	cnt = count_ident(src, len);
	if (!cnt)
		return 0;
 
	/* are we "faking" in place editing ? */
	if (src == buf->buf)
		to_free = strbuf_detach(buf, NULL);
	hash_object_file(the_hash_algo, src, len, "blob", &oid);
 
	strbuf_grow(buf, len + cnt * (the_hash_algo->hexsz + 3));
	for (;;) {
		/* step 1: run to the next '$' */
		dollar = memchr(src, '$', len);
		if (!dollar)
			break;
		strbuf_add(buf, src, dollar + 1 - src);
		len -= dollar + 1 - src;
		src  = dollar + 1;
 
		/* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
		if (len < 3 || memcmp("Id", src, 2))
			continue;
 
		/* step 3: skip over Id$ or Id:xxxxx$ */
		if (src[2] == '$') {
			src += 3;
			len -= 3;
		} else if (src[2] == ':') {
			/*
			 * It's possible that an expanded Id has crept its way into the
			 * repository, we cope with that by stripping the expansion out.
			 * This is probably not a good idea, since it will cause changes
			 * on checkout, which won't go away by stash, but let's keep it
			 * for git-style ids.
			 */
			dollar = memchr(src + 3, '$', len - 3);
			if (!dollar) {
				/* incomplete keyword, no more '$', so just quit the loop */
				break;
			}
 
			if (memchr(src + 3, '\n', dollar - src - 3)) {
				/* Line break before the next dollar. */
				continue;
			}
 
			spc = memchr(src + 4, ' ', dollar - src - 4);
			if (spc && spc < dollar-1) {
				/* There are spaces in unexpected places.
				 * This is probably an id from some other
				 * versioning system. Keep it for now.
				 */
				continue;
			}
 
			len -= dollar + 1 - src;
			src  = dollar + 1;
		} else {
			/* it wasn't a "Id$" or "Id:xxxx$" */
			continue;
		}
 
		/* step 4: substitute */
		strbuf_addstr(buf, "Id: ");
		strbuf_addstr(buf, oid_to_hex(&oid));
		strbuf_addstr(buf, " $");
	}
	strbuf_add(buf, src, len);
 
	free(to_free);
	return 1;
}
 
static const char *git_path_check_encoding(struct attr_check_item *check)
{
	const char *value = check->value;
 
	if (ATTR_UNSET(value) || !strlen(value))
		return NULL;
 
	if (ATTR_TRUE(value) || ATTR_FALSE(value)) {
		die(_("true/false are no valid working-tree-encodings"));
	}
 
	/* Don't encode to the default encoding */
	if (same_encoding(value, default_encoding))
		return NULL;
 
	return value;
}
 
static enum crlf_action git_path_check_crlf(struct attr_check_item *check)
{
	const char *value = check->value;
 
	if (ATTR_TRUE(value))
		return CRLF_TEXT;
	else if (ATTR_FALSE(value))
		return CRLF_BINARY;
	else if (ATTR_UNSET(value))
		;
	else if (!strcmp(value, "input"))
		return CRLF_TEXT_INPUT;
	else if (!strcmp(value, "auto"))
		return CRLF_AUTO;
	return CRLF_UNDEFINED;
}
 
static enum eol git_path_check_eol(struct attr_check_item *check)
{
	const char *value = check->value;
 
	if (ATTR_UNSET(value))
		;
	else if (!strcmp(value, "lf"))
		return EOL_LF;
	else if (!strcmp(value, "crlf"))
		return EOL_CRLF;
	return EOL_UNSET;
}
 
static struct convert_driver *git_path_check_convert(struct attr_check_item *check)
{
	const char *value = check->value;
	struct convert_driver *drv;
 
	if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
		return NULL;
	for (drv = user_convert; drv; drv = drv->next)
		if (!strcmp(value, drv->name))
			return drv;
	return NULL;
}
 
static int git_path_check_ident(struct attr_check_item *check)
{
	const char *value = check->value;
 
	return !!ATTR_TRUE(value);
}
 
struct conv_attrs {
	struct convert_driver *drv;
	enum crlf_action attr_action; /* What attr says */
	enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */
	int ident;
	const char *working_tree_encoding; /* Supported encoding or default encoding if NULL */
};
 
static struct attr_check *check;
 
static void convert_attrs(const struct index_state *istate,
			  struct conv_attrs *ca, const char *path)
{
	struct attr_check_item *ccheck = NULL;
 
	if (!check) {
		check = attr_check_initl("crlf", "ident", "filter",
					 "eol", "text", "working-tree-encoding",
					 NULL);
		user_convert_tail = &user_convert;
		git_config(read_convert_config, NULL);
	}
 
	git_check_attr(istate, path, check);
	ccheck = check->items;
	ca->crlf_action = git_path_check_crlf(ccheck + 4);
	if (ca->crlf_action == CRLF_UNDEFINED)
		ca->crlf_action = git_path_check_crlf(ccheck + 0);
	ca->ident = git_path_check_ident(ccheck + 1);
	ca->drv = git_path_check_convert(ccheck + 2);
	if (ca->crlf_action != CRLF_BINARY) {
		enum eol eol_attr = git_path_check_eol(ccheck + 3);
		if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_LF)
			ca->crlf_action = CRLF_AUTO_INPUT;
		else if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_CRLF)
			ca->crlf_action = CRLF_AUTO_CRLF;
		else if (eol_attr == EOL_LF)
			ca->crlf_action = CRLF_TEXT_INPUT;
		else if (eol_attr == EOL_CRLF)
			ca->crlf_action = CRLF_TEXT_CRLF;
	}
	ca->working_tree_encoding = git_path_check_encoding(ccheck + 5);
 
	/* Save attr and make a decision for action */
	ca->attr_action = ca->crlf_action;
	if (ca->crlf_action == CRLF_TEXT)
		ca->crlf_action = text_eol_is_crlf() ? CRLF_TEXT_CRLF : CRLF_TEXT_INPUT;
	if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_FALSE)
		ca->crlf_action = CRLF_BINARY;
	if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_TRUE)
		ca->crlf_action = CRLF_AUTO_CRLF;
	if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_INPUT)
		ca->crlf_action = CRLF_AUTO_INPUT;
}
 
void reset_parsed_attributes(void)
{
	struct convert_driver *drv, *next;
 
	attr_check_free(check);
	check = NULL;
	reset_merge_attributes();
 
	for (drv = user_convert; drv; drv = next) {
		next = drv->next;
		free((void *)drv->name);
		free(drv);
	}
	user_convert = NULL;
	user_convert_tail = NULL;
}
 
int would_convert_to_git_filter_fd(const struct index_state *istate, const char *path)
{
	struct conv_attrs ca;
 
	convert_attrs(istate, &ca, path);
	if (!ca.drv)
		return 0;
 
	/*
	 * Apply a filter to an fd only if the filter is required to succeed.
	 * We must die if the filter fails, because the original data before
	 * filtering is not available.
	 */
	if (!ca.drv->required)
		return 0;
 
	return apply_filter(path, NULL, 0, -1, NULL, ca.drv, CAP_CLEAN, NULL, NULL);
}
 
const char *get_convert_attr_ascii(const struct index_state *istate, const char *path)
{
	struct conv_attrs ca;
 
	convert_attrs(istate, &ca, path);
	switch (ca.attr_action) {
	case CRLF_UNDEFINED:
		return "";
	case CRLF_BINARY:
		return "-text";
	case CRLF_TEXT:
		return "text";
	case CRLF_TEXT_INPUT:
		return "text eol=lf";
	case CRLF_TEXT_CRLF:
		return "text eol=crlf";
	case CRLF_AUTO:
		return "text=auto";
	case CRLF_AUTO_CRLF:
		return "text=auto eol=crlf";
	case CRLF_AUTO_INPUT:
		return "text=auto eol=lf";
	}
	return "";
}
 
int convert_to_git(const struct index_state *istate,
		   const char *path, const char *src, size_t len,
		   struct strbuf *dst, int conv_flags)
{
	int ret = 0;
	struct conv_attrs ca;
 
	convert_attrs(istate, &ca, path);
 
	ret |= apply_filter(path, src, len, -1, dst, ca.drv, CAP_CLEAN, NULL, NULL);
	if (!ret && ca.drv && ca.drv->required)
		die(_("%s: clean filter '%s' failed"), path, ca.drv->name);
 
	if (ret && dst) {
		src = dst->buf;
		len = dst->len;
	}
 
	ret |= encode_to_git(path, src, len, dst, ca.working_tree_encoding, conv_flags);
	if (ret && dst) {
		src = dst->buf;
		len = dst->len;
	}
 
	if (!(conv_flags & CONV_EOL_KEEP_CRLF)) {
		ret |= crlf_to_git(istate, path, src, len, dst, ca.crlf_action, conv_flags);
		if (ret && dst) {
			src = dst->buf;
			len = dst->len;
		}
	}
	return ret | ident_to_git(src, len, dst, ca.ident);
}
 
void convert_to_git_filter_fd(const struct index_state *istate,
			      const char *path, int fd, struct strbuf *dst,
			      int conv_flags)
{
	struct conv_attrs ca;
	convert_attrs(istate, &ca, path);
 
	assert(ca.drv);
	assert(ca.drv->clean || ca.drv->process);
 
	if (!apply_filter(path, NULL, 0, fd, dst, ca.drv, CAP_CLEAN, NULL, NULL))
		die(_("%s: clean filter '%s' failed"), path, ca.drv->name);
 
	encode_to_git(path, dst->buf, dst->len, dst, ca.working_tree_encoding, conv_flags);
	crlf_to_git(istate, path, dst->buf, dst->len, dst, ca.crlf_action, conv_flags);
	ident_to_git(dst->buf, dst->len, dst, ca.ident);
}
 
static int convert_to_working_tree_internal(const struct index_state *istate,
					    const char *path, const char *src,
					    size_t len, struct strbuf *dst,
					    int normalizing,
					    const struct checkout_metadata *meta,
					    struct delayed_checkout *dco)
{
	int ret = 0, ret_filter = 0;
	struct conv_attrs ca;
 
	convert_attrs(istate, &ca, path);
 
	ret |= ident_to_worktree(src, len, dst, ca.ident);
	if (ret) {
		src = dst->buf;
		len = dst->len;
	}
	/*
	 * CRLF conversion can be skipped if normalizing, unless there
	 * is a smudge or process filter (even if the process filter doesn't
	 * support smudge).  The filters might expect CRLFs.
	 */
	if ((ca.drv && (ca.drv->smudge || ca.drv->process)) || !normalizing) {
		ret |= crlf_to_worktree(src, len, dst, ca.crlf_action);
		if (ret) {
			src = dst->buf;
			len = dst->len;
		}
	}
 
	ret |= encode_to_worktree(path, src, len, dst, ca.working_tree_encoding);
	if (ret) {
		src = dst->buf;
		len = dst->len;
	}
 
	ret_filter = apply_filter(
		path, src, len, -1, dst, ca.drv, CAP_SMUDGE, meta, dco);
	if (!ret_filter && ca.drv && ca.drv->required)
		die(_("%s: smudge filter %s failed"), path, ca.drv->name);
 
	return ret | ret_filter;
}
 
int async_convert_to_working_tree(const struct index_state *istate,
				  const char *path, const char *src,
				  size_t len, struct strbuf *dst,
				  const struct checkout_metadata *meta,
				  void *dco)
{
	return convert_to_working_tree_internal(istate, path, src, len, dst, 0, meta, dco);
}
 
int convert_to_working_tree(const struct index_state *istate,
			    const char *path, const char *src,
			    size_t len, struct strbuf *dst,
			    const struct checkout_metadata *meta)
{
	return convert_to_working_tree_internal(istate, path, src, len, dst, 0, meta, NULL);
}
 
int renormalize_buffer(const struct index_state *istate, const char *path,
		       const char *src, size_t len, struct strbuf *dst)
{
	int ret = convert_to_working_tree_internal(istate, path, src, len, dst, 1, NULL, NULL);
	if (ret) {
		src = dst->buf;
		len = dst->len;
	}
	return ret | convert_to_git(istate, path, src, len, dst, CONV_EOL_RENORMALIZE);
}
 
/*****************************************************************
 *
 * Streaming conversion support
 *
 *****************************************************************/
 
typedef int (*filter_fn)(struct stream_filter *,
			 const char *input, size_t *isize_p,
			 char *output, size_t *osize_p);
typedef void (*free_fn)(struct stream_filter *);
 
struct stream_filter_vtbl {
	filter_fn filter;
	free_fn free;
};
 
struct stream_filter {
	struct stream_filter_vtbl *vtbl;
};
 
static int null_filter_fn(struct stream_filter *filter,
			  const char *input, size_t *isize_p,
			  char *output, size_t *osize_p)
{
	size_t count;
 
	if (!input)
		return 0; /* we do not keep any states */
	count = *isize_p;
	if (*osize_p < count)
		count = *osize_p;
	if (count) {
		memmove(output, input, count);
		*isize_p -= count;
		*osize_p -= count;
	}
	return 0;
}
 
static void null_free_fn(struct stream_filter *filter)
{
	; /* nothing -- null instances are shared */
}
 
static struct stream_filter_vtbl null_vtbl = {
	null_filter_fn,
	null_free_fn,
};
 
static struct stream_filter null_filter_singleton = {
	&null_vtbl,
};
 
int is_null_stream_filter(struct stream_filter *filter)
{
	return filter == &null_filter_singleton;
}
 
 
/*
 * LF-to-CRLF filter
 */
 
struct lf_to_crlf_filter {
	struct stream_filter filter;
	unsigned has_held:1;
	char held;
};
 
static int lf_to_crlf_filter_fn(struct stream_filter *filter,
				const char *input, size_t *isize_p,
				char *output, size_t *osize_p)
{
	size_t count, o = 0;
	struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
 
	/*
	 * We may be holding onto the CR to see if it is followed by a
	 * LF, in which case we would need to go to the main loop.
	 * Otherwise, just emit it to the output stream.
	 */
	if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
		output[o++] = lf_to_crlf->held;
		lf_to_crlf->has_held = 0;
	}
 
	/* We are told to drain */
	if (!input) {
		*osize_p -= o;
		return 0;
	}
 
	count = *isize_p;
	if (count || lf_to_crlf->has_held) {
		size_t i;
		int was_cr = 0;
 
		if (lf_to_crlf->has_held) {
			was_cr = 1;
			lf_to_crlf->has_held = 0;
		}
 
		for (i = 0; o < *osize_p && i < count; i++) {
			char ch = input[i];
 
			if (ch == '\n') {
				output[o++] = '\r';
			} else if (was_cr) {
				/*
				 * Previous round saw CR and it is not followed
				 * by a LF; emit the CR before processing the
				 * current character.
				 */
				output[o++] = '\r';
			}
 
			/*
			 * We may have consumed the last output slot,
			 * in which case we need to break out of this
			 * loop; hold the current character before
			 * returning.
			 */
			if (*osize_p <= o) {
				lf_to_crlf->has_held = 1;
				lf_to_crlf->held = ch;
				continue; /* break but increment i */
			}
 
			if (ch == '\r') {
				was_cr = 1;
				continue;
			}
 
			was_cr = 0;
			output[o++] = ch;
		}
 
		*osize_p -= o;
		*isize_p -= i;
 
		if (!lf_to_crlf->has_held && was_cr) {
			lf_to_crlf->has_held = 1;
			lf_to_crlf->held = '\r';
		}
	}
	return 0;
}
 
static void lf_to_crlf_free_fn(struct stream_filter *filter)
{
	free(filter);
}
 
static struct stream_filter_vtbl lf_to_crlf_vtbl = {
	lf_to_crlf_filter_fn,
	lf_to_crlf_free_fn,
};
 
static struct stream_filter *lf_to_crlf_filter(void)
{
	struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
 
	lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
	return (struct stream_filter *)lf_to_crlf;
}
 
/*
 * Cascade filter
 */
#define FILTER_BUFFER 1024
struct cascade_filter {
	struct stream_filter filter;
	struct stream_filter *one;
	struct stream_filter *two;
	char buf[FILTER_BUFFER];
	int end, ptr;
};
 
static int cascade_filter_fn(struct stream_filter *filter,
			     const char *input, size_t *isize_p,
			     char *output, size_t *osize_p)
{
	struct cascade_filter *cas = (struct cascade_filter *) filter;
	size_t filled = 0;
	size_t sz = *osize_p;
	size_t to_feed, remaining;
 
	/*
	 * input -- (one) --> buf -- (two) --> output
	 */
	while (filled < sz) {
		remaining = sz - filled;
 
		/* do we already have something to feed two with? */
		if (cas->ptr < cas->end) {
			to_feed = cas->end - cas->ptr;
			if (stream_filter(cas->two,
					  cas->buf + cas->ptr, &to_feed,
					  output + filled, &remaining))
				return -1;
			cas->ptr += (cas->end - cas->ptr) - to_feed;
			filled = sz - remaining;
			continue;
		}
 
		/* feed one from upstream and have it emit into our buffer */
		to_feed = input ? *isize_p : 0;
		if (input && !to_feed)
			break;
		remaining = sizeof(cas->buf);
		if (stream_filter(cas->one,
				  input, &to_feed,
				  cas->buf, &remaining))
			return -1;
		cas->end = sizeof(cas->buf) - remaining;
		cas->ptr = 0;
		if (input) {
			size_t fed = *isize_p - to_feed;
			*isize_p -= fed;
			input += fed;
		}
 
		/* do we know that we drained one completely? */
		if (input || cas->end)
			continue;
 
		/* tell two to drain; we have nothing more to give it */
		to_feed = 0;
		remaining = sz - filled;
		if (stream_filter(cas->two,
				  NULL, &to_feed,
				  output + filled, &remaining))
			return -1;
		if (remaining == (sz - filled))
			break; /* completely drained two */
		filled = sz - remaining;
	}
	*osize_p -= filled;
	return 0;
}
 
static void cascade_free_fn(struct stream_filter *filter)
{
	struct cascade_filter *cas = (struct cascade_filter *)filter;
	free_stream_filter(cas->one);
	free_stream_filter(cas->two);
	free(filter);
}
 
static struct stream_filter_vtbl cascade_vtbl = {
	cascade_filter_fn,
	cascade_free_fn,
};
 
static struct stream_filter *cascade_filter(struct stream_filter *one,
					    struct stream_filter *two)
{
	struct cascade_filter *cascade;
 
	if (!one || is_null_stream_filter(one))
		return two;
	if (!two || is_null_stream_filter(two))
		return one;
 
	cascade = xmalloc(sizeof(*cascade));
	cascade->one = one;
	cascade->two = two;
	cascade->end = cascade->ptr = 0;
	cascade->filter.vtbl = &cascade_vtbl;
	return (struct stream_filter *)cascade;
}
 
/*
 * ident filter
 */
#define IDENT_DRAINING (-1)
#define IDENT_SKIPPING (-2)
struct ident_filter {
	struct stream_filter filter;
	struct strbuf left;
	int state;
	char ident[GIT_MAX_HEXSZ + 5]; /* ": x40 $" */
};
 
static int is_foreign_ident(const char *str)
{
	int i;
 
	if (!skip_prefix(str, "$Id: ", &str))
		return 0;
	for (i = 0; str[i]; i++) {
		if (isspace(str[i]) && str[i+1] != '$')
			return 1;
	}
	return 0;
}
 
static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
{
	size_t to_drain = ident->left.len;
 
	if (*osize_p < to_drain)
		to_drain = *osize_p;
	if (to_drain) {
		memcpy(*output_p, ident->left.buf, to_drain);
		strbuf_remove(&ident->left, 0, to_drain);
		*output_p += to_drain;
		*osize_p -= to_drain;
	}
	if (!ident->left.len)
		ident->state = 0;
}
 
static int ident_filter_fn(struct stream_filter *filter,
			   const char *input, size_t *isize_p,
			   char *output, size_t *osize_p)
{
	struct ident_filter *ident = (struct ident_filter *)filter;
	static const char head[] = "$Id";
 
	if (!input) {
		/* drain upon eof */
		switch (ident->state) {
		default:
			strbuf_add(&ident->left, head, ident->state);
			/* fallthrough */
		case IDENT_SKIPPING:
			/* fallthrough */
		case IDENT_DRAINING:
			ident_drain(ident, &output, osize_p);
		}
		return 0;
	}
 
	while (*isize_p || (ident->state == IDENT_DRAINING)) {
		int ch;
 
		if (ident->state == IDENT_DRAINING) {
			ident_drain(ident, &output, osize_p);
			if (!*osize_p)
				break;
			continue;
		}
 
		ch = *(input++);
		(*isize_p)--;
 
		if (ident->state == IDENT_SKIPPING) {
			/*
			 * Skipping until '$' or LF, but keeping them
			 * in case it is a foreign ident.
			 */
			strbuf_addch(&ident->left, ch);
			if (ch != '\n' && ch != '$')
				continue;
			if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
				strbuf_setlen(&ident->left, sizeof(head) - 1);
				strbuf_addstr(&ident->left, ident->ident);
			}
			ident->state = IDENT_DRAINING;
			continue;
		}
 
		if (ident->state < sizeof(head) &&
		    head[ident->state] == ch) {
			ident->state++;
			continue;
		}
 
		if (ident->state)
			strbuf_add(&ident->left, head, ident->state);
		if (ident->state == sizeof(head) - 1) {
			if (ch != ':' && ch != '$') {
				strbuf_addch(&ident->left, ch);
				ident->state = 0;
				continue;
			}
 
			if (ch == ':') {
				strbuf_addch(&ident->left, ch);
				ident->state = IDENT_SKIPPING;
			} else {
				strbuf_addstr(&ident->left, ident->ident);
				ident->state = IDENT_DRAINING;
			}
			continue;
		}
 
		strbuf_addch(&ident->left, ch);
		ident->state = IDENT_DRAINING;
	}
	return 0;
}
 
static void ident_free_fn(struct stream_filter *filter)
{
	struct ident_filter *ident = (struct ident_filter *)filter;
	strbuf_release(&ident->left);
	free(filter);
}
 
static struct stream_filter_vtbl ident_vtbl = {
	ident_filter_fn,
	ident_free_fn,
};
 
static struct stream_filter *ident_filter(const struct object_id *oid)
{
	struct ident_filter *ident = xmalloc(sizeof(*ident));
 
	xsnprintf(ident->ident, sizeof(ident->ident),
		  ": %s $", oid_to_hex(oid));
	strbuf_init(&ident->left, 0);
	ident->filter.vtbl = &ident_vtbl;
	ident->state = 0;
	return (struct stream_filter *)ident;
}
 
/*
 * Return an appropriately constructed filter for the path, or NULL if
 * the contents cannot be filtered without reading the whole thing
 * in-core.
 *
 * Note that you would be crazy to set CRLF, smudge/clean or ident to a
 * large binary blob you would want us not to slurp into the memory!
 */
struct stream_filter *get_stream_filter(const struct index_state *istate,
					const char *path,
					const struct object_id *oid)
{
	struct conv_attrs ca;
	struct stream_filter *filter = NULL;
 
	convert_attrs(istate, &ca, path);
	if (ca.drv && (ca.drv->process || ca.drv->smudge || ca.drv->clean))
		return NULL;
 
	if (ca.working_tree_encoding)
		return NULL;
 
	if (ca.crlf_action == CRLF_AUTO || ca.crlf_action == CRLF_AUTO_CRLF)
		return NULL;
 
	if (ca.ident)
		filter = ident_filter(oid);
 
	if (output_eol(ca.crlf_action) == EOL_CRLF)
		filter = cascade_filter(filter, lf_to_crlf_filter());
	else
		filter = cascade_filter(filter, &null_filter_singleton);
 
	return filter;
}
 
void free_stream_filter(struct stream_filter *filter)
{
	filter->vtbl->free(filter);
}
 
int stream_filter(struct stream_filter *filter,
		  const char *input, size_t *isize_p,
		  char *output, size_t *osize_p)
{
	return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
}