about summary refs log blame commit diff
path: root/third_party/git/ref-filter.c
blob: b1812cb69a173c983bf434bcab0522bb96d03dd0 (plain) (tree)
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
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
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
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
















































































                                                                         
                                 



                                                                    

                                                                       

                                                                      




                                                                        

























































































































































































                                                                                                            
                                                                        
            
                                                            












































































































































































































































































































































































































































































































































































































































































































































































                                                                                                                      
                           






                                              
                                   

                                     
                                   































































































































































































































































































































































































































                                                                                                 

                                  

                                                                               






































































































                                                                                                              

                                                                         
 
                                                      















                                                                                              
                                       




                                                          
                                                                          
 
               
                                   



                                                                           









































































































































































                                                                                           
                                                          





































































































































































































































                                                                                   
                                                               







































































































































































                                                                                                        

                                                                           













































































































































































































































































































































                                                                                                            
#include "builtin.h"
#include "cache.h"
#include "parse-options.h"
#include "refs.h"
#include "wildmatch.h"
#include "object-store.h"
#include "repository.h"
#include "commit.h"
#include "remote.h"
#include "color.h"
#include "tag.h"
#include "quote.h"
#include "ref-filter.h"
#include "revision.h"
#include "utf8.h"
#include "git-compat-util.h"
#include "version.h"
#include "trailer.h"
#include "wt-status.h"
#include "commit-slab.h"
#include "commit-graph.h"
#include "commit-reach.h"
#include "worktree.h"
#include "hashmap.h"
#include "argv-array.h"

static struct ref_msg {
	const char *gone;
	const char *ahead;
	const char *behind;
	const char *ahead_behind;
} msgs = {
	 /* Untranslated plumbing messages: */
	"gone",
	"ahead %d",
	"behind %d",
	"ahead %d, behind %d"
};

void setup_ref_filter_porcelain_msg(void)
{
	msgs.gone = _("gone");
	msgs.ahead = _("ahead %d");
	msgs.behind = _("behind %d");
	msgs.ahead_behind = _("ahead %d, behind %d");
}

typedef enum { FIELD_STR, FIELD_ULONG, FIELD_TIME } cmp_type;
typedef enum { COMPARE_EQUAL, COMPARE_UNEQUAL, COMPARE_NONE } cmp_status;
typedef enum { SOURCE_NONE = 0, SOURCE_OBJ, SOURCE_OTHER } info_source;

struct align {
	align_type position;
	unsigned int width;
};

struct if_then_else {
	cmp_status cmp_status;
	const char *str;
	unsigned int then_atom_seen : 1,
		else_atom_seen : 1,
		condition_satisfied : 1;
};

struct refname_atom {
	enum { R_NORMAL, R_SHORT, R_LSTRIP, R_RSTRIP } option;
	int lstrip, rstrip;
};

static struct expand_data {
	struct object_id oid;
	enum object_type type;
	unsigned long size;
	off_t disk_size;
	struct object_id delta_base_oid;
	void *content;

	struct object_info info;
} oi, oi_deref;

struct ref_to_worktree_entry {
	struct hashmap_entry ent;
	struct worktree *wt; /* key is wt->head_ref */
};

static int ref_to_worktree_map_cmpfnc(const void *unused_lookupdata,
				      const struct hashmap_entry *eptr,
				      const struct hashmap_entry *kptr,
				      const void *keydata_aka_refname)
{
	const struct ref_to_worktree_entry *e, *k;

	e = container_of(eptr, const struct ref_to_worktree_entry, ent);
	k = container_of(kptr, const struct ref_to_worktree_entry, ent);

	return strcmp(e->wt->head_ref,
		keydata_aka_refname ? keydata_aka_refname : k->wt->head_ref);
}

static struct ref_to_worktree_map {
	struct hashmap map;
	struct worktree **worktrees;
} ref_to_worktree_map;

/*
 * An atom is a valid field atom listed below, possibly prefixed with
 * a "*" to denote deref_tag().
 *
 * We parse given format string and sort specifiers, and make a list
 * of properties that we need to extract out of objects.  ref_array_item
 * structure will hold an array of values extracted that can be
 * indexed with the "atom number", which is an index into this
 * array.
 */
static struct used_atom {
	const char *name;
	cmp_type type;
	info_source source;
	union {
		char color[COLOR_MAXLEN];
		struct align align;
		struct {
			enum {
				RR_REF, RR_TRACK, RR_TRACKSHORT, RR_REMOTE_NAME, RR_REMOTE_REF
			} option;
			struct refname_atom refname;
			unsigned int nobracket : 1, push : 1, push_remote : 1;
		} remote_ref;
		struct {
			enum { C_BARE, C_BODY, C_BODY_DEP, C_LINES, C_SIG, C_SUB, C_TRAILERS } option;
			struct process_trailer_options trailer_opts;
			unsigned int nlines;
		} contents;
		struct {
			cmp_status cmp_status;
			const char *str;
		} if_then_else;
		struct {
			enum { O_FULL, O_LENGTH, O_SHORT } option;
			unsigned int length;
		} objectname;
		struct refname_atom refname;
		char *head;
	} u;
} *used_atom;
static int used_atom_cnt, need_tagged, need_symref;

/*
 * Expand string, append it to strbuf *sb, then return error code ret.
 * Allow to save few lines of code.
 */
static int strbuf_addf_ret(struct strbuf *sb, int ret, const char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	strbuf_vaddf(sb, fmt, ap);
	va_end(ap);
	return ret;
}

static int color_atom_parser(const struct ref_format *format, struct used_atom *atom,
			     const char *color_value, struct strbuf *err)
{
	if (!color_value)
		return strbuf_addf_ret(err, -1, _("expected format: %%(color:<color>)"));
	if (color_parse(color_value, atom->u.color) < 0)
		return strbuf_addf_ret(err, -1, _("unrecognized color: %%(color:%s)"),
				       color_value);
	/*
	 * We check this after we've parsed the color, which lets us complain
	 * about syntactically bogus color names even if they won't be used.
	 */
	if (!want_color(format->use_color))
		color_parse("", atom->u.color);
	return 0;
}

static int refname_atom_parser_internal(struct refname_atom *atom, const char *arg,
					 const char *name, struct strbuf *err)
{
	if (!arg)
		atom->option = R_NORMAL;
	else if (!strcmp(arg, "short"))
		atom->option = R_SHORT;
	else if (skip_prefix(arg, "lstrip=", &arg) ||
		 skip_prefix(arg, "strip=", &arg)) {
		atom->option = R_LSTRIP;
		if (strtol_i(arg, 10, &atom->lstrip))
			return strbuf_addf_ret(err, -1, _("Integer value expected refname:lstrip=%s"), arg);
	} else if (skip_prefix(arg, "rstrip=", &arg)) {
		atom->option = R_RSTRIP;
		if (strtol_i(arg, 10, &atom->rstrip))
			return strbuf_addf_ret(err, -1, _("Integer value expected refname:rstrip=%s"), arg);
	} else
		return strbuf_addf_ret(err, -1, _("unrecognized %%(%s) argument: %s"), name, arg);
	return 0;
}

static int remote_ref_atom_parser(const struct ref_format *format, struct used_atom *atom,
				  const char *arg, struct strbuf *err)
{
	struct string_list params = STRING_LIST_INIT_DUP;
	int i;

	if (!strcmp(atom->name, "push") || starts_with(atom->name, "push:"))
		atom->u.remote_ref.push = 1;

	if (!arg) {
		atom->u.remote_ref.option = RR_REF;
		return refname_atom_parser_internal(&atom->u.remote_ref.refname,
						    arg, atom->name, err);
	}

	atom->u.remote_ref.nobracket = 0;
	string_list_split(&params, arg, ',', -1);

	for (i = 0; i < params.nr; i++) {
		const char *s = params.items[i].string;

		if (!strcmp(s, "track"))
			atom->u.remote_ref.option = RR_TRACK;
		else if (!strcmp(s, "trackshort"))
			atom->u.remote_ref.option = RR_TRACKSHORT;
		else if (!strcmp(s, "nobracket"))
			atom->u.remote_ref.nobracket = 1;
		else if (!strcmp(s, "remotename")) {
			atom->u.remote_ref.option = RR_REMOTE_NAME;
			atom->u.remote_ref.push_remote = 1;
		} else if (!strcmp(s, "remoteref")) {
			atom->u.remote_ref.option = RR_REMOTE_REF;
			atom->u.remote_ref.push_remote = 1;
		} else {
			atom->u.remote_ref.option = RR_REF;
			if (refname_atom_parser_internal(&atom->u.remote_ref.refname,
							 arg, atom->name, err)) {
				string_list_clear(&params, 0);
				return -1;
			}
		}
	}

	string_list_clear(&params, 0);
	return 0;
}

static int objecttype_atom_parser(const struct ref_format *format, struct used_atom *atom,
				  const char *arg, struct strbuf *err)
{
	if (arg)
		return strbuf_addf_ret(err, -1, _("%%(objecttype) does not take arguments"));
	if (*atom->name == '*')
		oi_deref.info.typep = &oi_deref.type;
	else
		oi.info.typep = &oi.type;
	return 0;
}

static int objectsize_atom_parser(const struct ref_format *format, struct used_atom *atom,
				  const char *arg, struct strbuf *err)
{
	if (!arg) {
		if (*atom->name == '*')
			oi_deref.info.sizep = &oi_deref.size;
		else
			oi.info.sizep = &oi.size;
	} else if (!strcmp(arg, "disk")) {
		if (*atom->name == '*')
			oi_deref.info.disk_sizep = &oi_deref.disk_size;
		else
			oi.info.disk_sizep = &oi.disk_size;
	} else
		return strbuf_addf_ret(err, -1, _("unrecognized %%(objectsize) argument: %s"), arg);
	return 0;
}

static int deltabase_atom_parser(const struct ref_format *format, struct used_atom *atom,
				 const char *arg, struct strbuf *err)
{
	if (arg)
		return strbuf_addf_ret(err, -1, _("%%(deltabase) does not take arguments"));
	if (*atom->name == '*')
		oi_deref.info.delta_base_oid = &oi_deref.delta_base_oid;
	else
		oi.info.delta_base_oid = &oi.delta_base_oid;
	return 0;
}

static int body_atom_parser(const struct ref_format *format, struct used_atom *atom,
			    const char *arg, struct strbuf *err)
{
	if (arg)
		return strbuf_addf_ret(err, -1, _("%%(body) does not take arguments"));
	atom->u.contents.option = C_BODY_DEP;
	return 0;
}

static int subject_atom_parser(const struct ref_format *format, struct used_atom *atom,
			       const char *arg, struct strbuf *err)
{
	if (arg)
		return strbuf_addf_ret(err, -1, _("%%(subject) does not take arguments"));
	atom->u.contents.option = C_SUB;
	return 0;
}

static int trailers_atom_parser(const struct ref_format *format, struct used_atom *atom,
				const char *arg, struct strbuf *err)
{
	struct string_list params = STRING_LIST_INIT_DUP;
	int i;

	atom->u.contents.trailer_opts.no_divider = 1;

	if (arg) {
		string_list_split(&params, arg, ',', -1);
		for (i = 0; i < params.nr; i++) {
			const char *s = params.items[i].string;
			if (!strcmp(s, "unfold"))
				atom->u.contents.trailer_opts.unfold = 1;
			else if (!strcmp(s, "only"))
				atom->u.contents.trailer_opts.only_trailers = 1;
			else {
				strbuf_addf(err, _("unknown %%(trailers) argument: %s"), s);
				string_list_clear(&params, 0);
				return -1;
			}
		}
	}
	atom->u.contents.option = C_TRAILERS;
	string_list_clear(&params, 0);
	return 0;
}

static int contents_atom_parser(const struct ref_format *format, struct used_atom *atom,
				const char *arg, struct strbuf *err)
{
	if (!arg)
		atom->u.contents.option = C_BARE;
	else if (!strcmp(arg, "body"))
		atom->u.contents.option = C_BODY;
	else if (!strcmp(arg, "signature"))
		atom->u.contents.option = C_SIG;
	else if (!strcmp(arg, "subject"))
		atom->u.contents.option = C_SUB;
	else if (skip_prefix(arg, "trailers", &arg)) {
		skip_prefix(arg, ":", &arg);
		if (trailers_atom_parser(format, atom, *arg ? arg : NULL, err))
			return -1;
	} else if (skip_prefix(arg, "lines=", &arg)) {
		atom->u.contents.option = C_LINES;
		if (strtoul_ui(arg, 10, &atom->u.contents.nlines))
			return strbuf_addf_ret(err, -1, _("positive value expected contents:lines=%s"), arg);
	} else
		return strbuf_addf_ret(err, -1, _("unrecognized %%(contents) argument: %s"), arg);
	return 0;
}

static int objectname_atom_parser(const struct ref_format *format, struct used_atom *atom,
				  const char *arg, struct strbuf *err)
{
	if (!arg)
		atom->u.objectname.option = O_FULL;
	else if (!strcmp(arg, "short"))
		atom->u.objectname.option = O_SHORT;
	else if (skip_prefix(arg, "short=", &arg)) {
		atom->u.objectname.option = O_LENGTH;
		if (strtoul_ui(arg, 10, &atom->u.objectname.length) ||
		    atom->u.objectname.length == 0)
			return strbuf_addf_ret(err, -1, _("positive value expected objectname:short=%s"), arg);
		if (atom->u.objectname.length < MINIMUM_ABBREV)
			atom->u.objectname.length = MINIMUM_ABBREV;
	} else
		return strbuf_addf_ret(err, -1, _("unrecognized %%(objectname) argument: %s"), arg);
	return 0;
}

static int refname_atom_parser(const struct ref_format *format, struct used_atom *atom,
			       const char *arg, struct strbuf *err)
{
	return refname_atom_parser_internal(&atom->u.refname, arg, atom->name, err);
}

static align_type parse_align_position(const char *s)
{
	if (!strcmp(s, "right"))
		return ALIGN_RIGHT;
	else if (!strcmp(s, "middle"))
		return ALIGN_MIDDLE;
	else if (!strcmp(s, "left"))
		return ALIGN_LEFT;
	return -1;
}

static int align_atom_parser(const struct ref_format *format, struct used_atom *atom,
			     const char *arg, struct strbuf *err)
{
	struct align *align = &atom->u.align;
	struct string_list params = STRING_LIST_INIT_DUP;
	int i;
	unsigned int width = ~0U;

	if (!arg)
		return strbuf_addf_ret(err, -1, _("expected format: %%(align:<width>,<position>)"));

	align->position = ALIGN_LEFT;

	string_list_split(&params, arg, ',', -1);
	for (i = 0; i < params.nr; i++) {
		const char *s = params.items[i].string;
		int position;

		if (skip_prefix(s, "position=", &s)) {
			position = parse_align_position(s);
			if (position < 0) {
				strbuf_addf(err, _("unrecognized position:%s"), s);
				string_list_clear(&params, 0);
				return -1;
			}
			align->position = position;
		} else if (skip_prefix(s, "width=", &s)) {
			if (strtoul_ui(s, 10, &width)) {
				strbuf_addf(err, _("unrecognized width:%s"), s);
				string_list_clear(&params, 0);
				return -1;
			}
		} else if (!strtoul_ui(s, 10, &width))
			;
		else if ((position = parse_align_position(s)) >= 0)
			align->position = position;
		else {
			strbuf_addf(err, _("unrecognized %%(align) argument: %s"), s);
			string_list_clear(&params, 0);
			return -1;
		}
	}

	if (width == ~0U) {
		string_list_clear(&params, 0);
		return strbuf_addf_ret(err, -1, _("positive width expected with the %%(align) atom"));
	}
	align->width = width;
	string_list_clear(&params, 0);
	return 0;
}

static int if_atom_parser(const struct ref_format *format, struct used_atom *atom,
			  const char *arg, struct strbuf *err)
{
	if (!arg) {
		atom->u.if_then_else.cmp_status = COMPARE_NONE;
		return 0;
	} else if (skip_prefix(arg, "equals=", &atom->u.if_then_else.str)) {
		atom->u.if_then_else.cmp_status = COMPARE_EQUAL;
	} else if (skip_prefix(arg, "notequals=", &atom->u.if_then_else.str)) {
		atom->u.if_then_else.cmp_status = COMPARE_UNEQUAL;
	} else
		return strbuf_addf_ret(err, -1, _("unrecognized %%(if) argument: %s"), arg);
	return 0;
}

static int head_atom_parser(const struct ref_format *format, struct used_atom *atom,
			    const char *arg, struct strbuf *unused_err)
{
	atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, NULL, NULL);
	return 0;
}

static struct {
	const char *name;
	info_source source;
	cmp_type cmp_type;
	int (*parser)(const struct ref_format *format, struct used_atom *atom,
		      const char *arg, struct strbuf *err);
} valid_atom[] = {
	{ "refname", SOURCE_NONE, FIELD_STR, refname_atom_parser },
	{ "objecttype", SOURCE_OTHER, FIELD_STR, objecttype_atom_parser },
	{ "objectsize", SOURCE_OTHER, FIELD_ULONG, objectsize_atom_parser },
	{ "objectname", SOURCE_OTHER, FIELD_STR, objectname_atom_parser },
	{ "deltabase", SOURCE_OTHER, FIELD_STR, deltabase_atom_parser },
	{ "tree", SOURCE_OBJ },
	{ "parent", SOURCE_OBJ },
	{ "numparent", SOURCE_OBJ, FIELD_ULONG },
	{ "object", SOURCE_OBJ },
	{ "type", SOURCE_OBJ },
	{ "tag", SOURCE_OBJ },
	{ "author", SOURCE_OBJ },
	{ "authorname", SOURCE_OBJ },
	{ "authoremail", SOURCE_OBJ },
	{ "authordate", SOURCE_OBJ, FIELD_TIME },
	{ "committer", SOURCE_OBJ },
	{ "committername", SOURCE_OBJ },
	{ "committeremail", SOURCE_OBJ },
	{ "committerdate", SOURCE_OBJ, FIELD_TIME },
	{ "tagger", SOURCE_OBJ },
	{ "taggername", SOURCE_OBJ },
	{ "taggeremail", SOURCE_OBJ },
	{ "taggerdate", SOURCE_OBJ, FIELD_TIME },
	{ "creator", SOURCE_OBJ },
	{ "creatordate", SOURCE_OBJ, FIELD_TIME },
	{ "subject", SOURCE_OBJ, FIELD_STR, subject_atom_parser },
	{ "body", SOURCE_OBJ, FIELD_STR, body_atom_parser },
	{ "trailers", SOURCE_OBJ, FIELD_STR, trailers_atom_parser },
	{ "contents", SOURCE_OBJ, FIELD_STR, contents_atom_parser },
	{ "upstream", SOURCE_NONE, FIELD_STR, remote_ref_atom_parser },
	{ "push", SOURCE_NONE, FIELD_STR, remote_ref_atom_parser },
	{ "symref", SOURCE_NONE, FIELD_STR, refname_atom_parser },
	{ "flag", SOURCE_NONE },
	{ "HEAD", SOURCE_NONE, FIELD_STR, head_atom_parser },
	{ "color", SOURCE_NONE, FIELD_STR, color_atom_parser },
	{ "worktreepath", SOURCE_NONE },
	{ "align", SOURCE_NONE, FIELD_STR, align_atom_parser },
	{ "end", SOURCE_NONE },
	{ "if", SOURCE_NONE, FIELD_STR, if_atom_parser },
	{ "then", SOURCE_NONE },
	{ "else", SOURCE_NONE },
	/*
	 * Please update $__git_ref_fieldlist in git-completion.bash
	 * when you add new atoms
	 */
};

#define REF_FORMATTING_STATE_INIT  { 0, NULL }

struct ref_formatting_stack {
	struct ref_formatting_stack *prev;
	struct strbuf output;
	void (*at_end)(struct ref_formatting_stack **stack);
	void *at_end_data;
};

struct ref_formatting_state {
	int quote_style;
	struct ref_formatting_stack *stack;
};

struct atom_value {
	const char *s;
	int (*handler)(struct atom_value *atomv, struct ref_formatting_state *state,
		       struct strbuf *err);
	uintmax_t value; /* used for sorting when not FIELD_STR */
	struct used_atom *atom;
};

/*
 * Used to parse format string and sort specifiers
 */
static int parse_ref_filter_atom(const struct ref_format *format,
				 const char *atom, const char *ep,
				 struct strbuf *err)
{
	const char *sp;
	const char *arg;
	int i, at, atom_len;

	sp = atom;
	if (*sp == '*' && sp < ep)
		sp++; /* deref */
	if (ep <= sp)
		return strbuf_addf_ret(err, -1, _("malformed field name: %.*s"),
				       (int)(ep-atom), atom);

	/* Do we have the atom already used elsewhere? */
	for (i = 0; i < used_atom_cnt; i++) {
		int len = strlen(used_atom[i].name);
		if (len == ep - atom && !memcmp(used_atom[i].name, atom, len))
			return i;
	}

	/*
	 * If the atom name has a colon, strip it and everything after
	 * it off - it specifies the format for this entry, and
	 * shouldn't be used for checking against the valid_atom
	 * table.
	 */
	arg = memchr(sp, ':', ep - sp);
	atom_len = (arg ? arg : ep) - sp;

	/* Is the atom a valid one? */
	for (i = 0; i < ARRAY_SIZE(valid_atom); i++) {
		int len = strlen(valid_atom[i].name);
		if (len == atom_len && !memcmp(valid_atom[i].name, sp, len))
			break;
	}

	if (ARRAY_SIZE(valid_atom) <= i)
		return strbuf_addf_ret(err, -1, _("unknown field name: %.*s"),
				       (int)(ep-atom), atom);
	if (valid_atom[i].source != SOURCE_NONE && !have_git_dir())
		return strbuf_addf_ret(err, -1,
				       _("not a git repository, but the field '%.*s' requires access to object data"),
				       (int)(ep-atom), atom);

	/* Add it in, including the deref prefix */
	at = used_atom_cnt;
	used_atom_cnt++;
	REALLOC_ARRAY(used_atom, used_atom_cnt);
	used_atom[at].name = xmemdupz(atom, ep - atom);
	used_atom[at].type = valid_atom[i].cmp_type;
	used_atom[at].source = valid_atom[i].source;
	if (used_atom[at].source == SOURCE_OBJ) {
		if (*atom == '*')
			oi_deref.info.contentp = &oi_deref.content;
		else
			oi.info.contentp = &oi.content;
	}
	if (arg) {
		arg = used_atom[at].name + (arg - atom) + 1;
		if (!*arg) {
			/*
			 * Treat empty sub-arguments list as NULL (i.e.,
			 * "%(atom:)" is equivalent to "%(atom)").
			 */
			arg = NULL;
		}
	}
	memset(&used_atom[at].u, 0, sizeof(used_atom[at].u));
	if (valid_atom[i].parser && valid_atom[i].parser(format, &used_atom[at], arg, err))
		return -1;
	if (*atom == '*')
		need_tagged = 1;
	if (!strcmp(valid_atom[i].name, "symref"))
		need_symref = 1;
	return at;
}

static void quote_formatting(struct strbuf *s, const char *str, int quote_style)
{
	switch (quote_style) {
	case QUOTE_NONE:
		strbuf_addstr(s, str);
		break;
	case QUOTE_SHELL:
		sq_quote_buf(s, str);
		break;
	case QUOTE_PERL:
		perl_quote_buf(s, str);
		break;
	case QUOTE_PYTHON:
		python_quote_buf(s, str);
		break;
	case QUOTE_TCL:
		tcl_quote_buf(s, str);
		break;
	}
}

static int append_atom(struct atom_value *v, struct ref_formatting_state *state,
		       struct strbuf *unused_err)
{
	/*
	 * Quote formatting is only done when the stack has a single
	 * element. Otherwise quote formatting is done on the
	 * element's entire output strbuf when the %(end) atom is
	 * encountered.
	 */
	if (!state->stack->prev)
		quote_formatting(&state->stack->output, v->s, state->quote_style);
	else
		strbuf_addstr(&state->stack->output, v->s);
	return 0;
}

static void push_stack_element(struct ref_formatting_stack **stack)
{
	struct ref_formatting_stack *s = xcalloc(1, sizeof(struct ref_formatting_stack));

	strbuf_init(&s->output, 0);
	s->prev = *stack;
	*stack = s;
}

static void pop_stack_element(struct ref_formatting_stack **stack)
{
	struct ref_formatting_stack *current = *stack;
	struct ref_formatting_stack *prev = current->prev;

	if (prev)
		strbuf_addbuf(&prev->output, &current->output);
	strbuf_release(&current->output);
	free(current);
	*stack = prev;
}

static void end_align_handler(struct ref_formatting_stack **stack)
{
	struct ref_formatting_stack *cur = *stack;
	struct align *align = (struct align *)cur->at_end_data;
	struct strbuf s = STRBUF_INIT;

	strbuf_utf8_align(&s, align->position, align->width, cur->output.buf);
	strbuf_swap(&cur->output, &s);
	strbuf_release(&s);
}

static int align_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
			      struct strbuf *unused_err)
{
	struct ref_formatting_stack *new_stack;

	push_stack_element(&state->stack);
	new_stack = state->stack;
	new_stack->at_end = end_align_handler;
	new_stack->at_end_data = &atomv->atom->u.align;
	return 0;
}

static void if_then_else_handler(struct ref_formatting_stack **stack)
{
	struct ref_formatting_stack *cur = *stack;
	struct ref_formatting_stack *prev = cur->prev;
	struct if_then_else *if_then_else = (struct if_then_else *)cur->at_end_data;

	if (!if_then_else->then_atom_seen)
		die(_("format: %%(if) atom used without a %%(then) atom"));

	if (if_then_else->else_atom_seen) {
		/*
		 * There is an %(else) atom: we need to drop one state from the
		 * stack, either the %(else) branch if the condition is satisfied, or
		 * the %(then) branch if it isn't.
		 */
		if (if_then_else->condition_satisfied) {
			strbuf_reset(&cur->output);
			pop_stack_element(&cur);
		} else {
			strbuf_swap(&cur->output, &prev->output);
			strbuf_reset(&cur->output);
			pop_stack_element(&cur);
		}
	} else if (!if_then_else->condition_satisfied) {
		/*
		 * No %(else) atom: just drop the %(then) branch if the
		 * condition is not satisfied.
		 */
		strbuf_reset(&cur->output);
	}

	*stack = cur;
	free(if_then_else);
}

static int if_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
			   struct strbuf *unused_err)
{
	struct ref_formatting_stack *new_stack;
	struct if_then_else *if_then_else = xcalloc(sizeof(struct if_then_else), 1);

	if_then_else->str = atomv->atom->u.if_then_else.str;
	if_then_else->cmp_status = atomv->atom->u.if_then_else.cmp_status;

	push_stack_element(&state->stack);
	new_stack = state->stack;
	new_stack->at_end = if_then_else_handler;
	new_stack->at_end_data = if_then_else;
	return 0;
}

static int is_empty(const char *s)
{
	while (*s != '\0') {
		if (!isspace(*s))
			return 0;
		s++;
	}
	return 1;
}

static int then_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
			     struct strbuf *err)
{
	struct ref_formatting_stack *cur = state->stack;
	struct if_then_else *if_then_else = NULL;

	if (cur->at_end == if_then_else_handler)
		if_then_else = (struct if_then_else *)cur->at_end_data;
	if (!if_then_else)
		return strbuf_addf_ret(err, -1, _("format: %%(then) atom used without an %%(if) atom"));
	if (if_then_else->then_atom_seen)
		return strbuf_addf_ret(err, -1, _("format: %%(then) atom used more than once"));
	if (if_then_else->else_atom_seen)
		return strbuf_addf_ret(err, -1, _("format: %%(then) atom used after %%(else)"));
	if_then_else->then_atom_seen = 1;
	/*
	 * If the 'equals' or 'notequals' attribute is used then
	 * perform the required comparison. If not, only non-empty
	 * strings satisfy the 'if' condition.
	 */
	if (if_then_else->cmp_status == COMPARE_EQUAL) {
		if (!strcmp(if_then_else->str, cur->output.buf))
			if_then_else->condition_satisfied = 1;
	} else if (if_then_else->cmp_status == COMPARE_UNEQUAL) {
		if (strcmp(if_then_else->str, cur->output.buf))
			if_then_else->condition_satisfied = 1;
	} else if (cur->output.len && !is_empty(cur->output.buf))
		if_then_else->condition_satisfied = 1;
	strbuf_reset(&cur->output);
	return 0;
}

static int else_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
			     struct strbuf *err)
{
	struct ref_formatting_stack *prev = state->stack;
	struct if_then_else *if_then_else = NULL;

	if (prev->at_end == if_then_else_handler)
		if_then_else = (struct if_then_else *)prev->at_end_data;
	if (!if_then_else)
		return strbuf_addf_ret(err, -1, _("format: %%(else) atom used without an %%(if) atom"));
	if (!if_then_else->then_atom_seen)
		return strbuf_addf_ret(err, -1, _("format: %%(else) atom used without a %%(then) atom"));
	if (if_then_else->else_atom_seen)
		return strbuf_addf_ret(err, -1, _("format: %%(else) atom used more than once"));
	if_then_else->else_atom_seen = 1;
	push_stack_element(&state->stack);
	state->stack->at_end_data = prev->at_end_data;
	state->stack->at_end = prev->at_end;
	return 0;
}

static int end_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
			    struct strbuf *err)
{
	struct ref_formatting_stack *current = state->stack;
	struct strbuf s = STRBUF_INIT;

	if (!current->at_end)
		return strbuf_addf_ret(err, -1, _("format: %%(end) atom used without corresponding atom"));
	current->at_end(&state->stack);

	/*  Stack may have been popped within at_end(), hence reset the current pointer */
	current = state->stack;

	/*
	 * Perform quote formatting when the stack element is that of
	 * a supporting atom. If nested then perform quote formatting
	 * only on the topmost supporting atom.
	 */
	if (!current->prev->prev) {
		quote_formatting(&s, current->output.buf, state->quote_style);
		strbuf_swap(&current->output, &s);
	}
	strbuf_release(&s);
	pop_stack_element(&state->stack);
	return 0;
}

/*
 * In a format string, find the next occurrence of %(atom).
 */
static const char *find_next(const char *cp)
{
	while (*cp) {
		if (*cp == '%') {
			/*
			 * %( is the start of an atom;
			 * %% is a quoted per-cent.
			 */
			if (cp[1] == '(')
				return cp;
			else if (cp[1] == '%')
				cp++; /* skip over two % */
			/* otherwise this is a singleton, literal % */
		}
		cp++;
	}
	return NULL;
}

/*
 * Make sure the format string is well formed, and parse out
 * the used atoms.
 */
int verify_ref_format(struct ref_format *format)
{
	const char *cp, *sp;

	format->need_color_reset_at_eol = 0;
	for (cp = format->format; *cp && (sp = find_next(cp)); ) {
		struct strbuf err = STRBUF_INIT;
		const char *color, *ep = strchr(sp, ')');
		int at;

		if (!ep)
			return error(_("malformed format string %s"), sp);
		/* sp points at "%(" and ep points at the closing ")" */
		at = parse_ref_filter_atom(format, sp + 2, ep, &err);
		if (at < 0)
			die("%s", err.buf);
		cp = ep + 1;

		if (skip_prefix(used_atom[at].name, "color:", &color))
			format->need_color_reset_at_eol = !!strcmp(color, "reset");
		strbuf_release(&err);
	}
	if (format->need_color_reset_at_eol && !want_color(format->use_color))
		format->need_color_reset_at_eol = 0;
	return 0;
}

static int grab_objectname(const char *name, const struct object_id *oid,
			   struct atom_value *v, struct used_atom *atom)
{
	if (starts_with(name, "objectname")) {
		if (atom->u.objectname.option == O_SHORT) {
			v->s = xstrdup(find_unique_abbrev(oid, DEFAULT_ABBREV));
			return 1;
		} else if (atom->u.objectname.option == O_FULL) {
			v->s = xstrdup(oid_to_hex(oid));
			return 1;
		} else if (atom->u.objectname.option == O_LENGTH) {
			v->s = xstrdup(find_unique_abbrev(oid, atom->u.objectname.length));
			return 1;
		} else
			BUG("unknown %%(objectname) option");
	}
	return 0;
}

/* See grab_values */
static void grab_common_values(struct atom_value *val, int deref, struct expand_data *oi)
{
	int i;

	for (i = 0; i < used_atom_cnt; i++) {
		const char *name = used_atom[i].name;
		struct atom_value *v = &val[i];
		if (!!deref != (*name == '*'))
			continue;
		if (deref)
			name++;
		if (!strcmp(name, "objecttype"))
			v->s = xstrdup(type_name(oi->type));
		else if (!strcmp(name, "objectsize:disk")) {
			v->value = oi->disk_size;
			v->s = xstrfmt("%"PRIuMAX, (uintmax_t)oi->disk_size);
		} else if (!strcmp(name, "objectsize")) {
			v->value = oi->size;
			v->s = xstrfmt("%"PRIuMAX , (uintmax_t)oi->size);
		} else if (!strcmp(name, "deltabase"))
			v->s = xstrdup(oid_to_hex(&oi->delta_base_oid));
		else if (deref)
			grab_objectname(name, &oi->oid, v, &used_atom[i]);
	}
}

/* See grab_values */
static void grab_tag_values(struct atom_value *val, int deref, struct object *obj)
{
	int i;
	struct tag *tag = (struct tag *) obj;

	for (i = 0; i < used_atom_cnt; i++) {
		const char *name = used_atom[i].name;
		struct atom_value *v = &val[i];
		if (!!deref != (*name == '*'))
			continue;
		if (deref)
			name++;
		if (!strcmp(name, "tag"))
			v->s = xstrdup(tag->tag);
		else if (!strcmp(name, "type") && tag->tagged)
			v->s = xstrdup(type_name(tag->tagged->type));
		else if (!strcmp(name, "object") && tag->tagged)
			v->s = xstrdup(oid_to_hex(&tag->tagged->oid));
	}
}

/* See grab_values */
static void grab_commit_values(struct atom_value *val, int deref, struct object *obj)
{
	int i;
	struct commit *commit = (struct commit *) obj;

	for (i = 0; i < used_atom_cnt; i++) {
		const char *name = used_atom[i].name;
		struct atom_value *v = &val[i];
		if (!!deref != (*name == '*'))
			continue;
		if (deref)
			name++;
		if (!strcmp(name, "tree")) {
			v->s = xstrdup(oid_to_hex(get_commit_tree_oid(commit)));
		}
		else if (!strcmp(name, "numparent")) {
			v->value = commit_list_count(commit->parents);
			v->s = xstrfmt("%lu", (unsigned long)v->value);
		}
		else if (!strcmp(name, "parent")) {
			struct commit_list *parents;
			struct strbuf s = STRBUF_INIT;
			for (parents = commit->parents; parents; parents = parents->next) {
				struct commit *parent = parents->item;
				if (parents != commit->parents)
					strbuf_addch(&s, ' ');
				strbuf_addstr(&s, oid_to_hex(&parent->object.oid));
			}
			v->s = strbuf_detach(&s, NULL);
		}
	}
}

static const char *find_wholine(const char *who, int wholen, const char *buf)
{
	const char *eol;
	while (*buf) {
		if (!strncmp(buf, who, wholen) &&
		    buf[wholen] == ' ')
			return buf + wholen + 1;
		eol = strchr(buf, '\n');
		if (!eol)
			return "";
		eol++;
		if (*eol == '\n')
			return ""; /* end of header */
		buf = eol;
	}
	return "";
}

static const char *copy_line(const char *buf)
{
	const char *eol = strchrnul(buf, '\n');
	return xmemdupz(buf, eol - buf);
}

static const char *copy_name(const char *buf)
{
	const char *cp;
	for (cp = buf; *cp && *cp != '\n'; cp++) {
		if (!strncmp(cp, " <", 2))
			return xmemdupz(buf, cp - buf);
	}
	return xstrdup("");
}

static const char *copy_email(const char *buf)
{
	const char *email = strchr(buf, '<');
	const char *eoemail;
	if (!email)
		return xstrdup("");
	eoemail = strchr(email, '>');
	if (!eoemail)
		return xstrdup("");
	return xmemdupz(email, eoemail + 1 - email);
}

static char *copy_subject(const char *buf, unsigned long len)
{
	char *r = xmemdupz(buf, len);
	int i;

	for (i = 0; i < len; i++)
		if (r[i] == '\n')
			r[i] = ' ';

	return r;
}

static void grab_date(const char *buf, struct atom_value *v, const char *atomname)
{
	const char *eoemail = strstr(buf, "> ");
	char *zone;
	timestamp_t timestamp;
	long tz;
	struct date_mode date_mode = { DATE_NORMAL };
	const char *formatp;

	/*
	 * We got here because atomname ends in "date" or "date<something>";
	 * it's not possible that <something> is not ":<format>" because
	 * parse_ref_filter_atom() wouldn't have allowed it, so we can assume that no
	 * ":" means no format is specified, and use the default.
	 */
	formatp = strchr(atomname, ':');
	if (formatp != NULL) {
		formatp++;
		parse_date_format(formatp, &date_mode);
	}

	if (!eoemail)
		goto bad;
	timestamp = parse_timestamp(eoemail + 2, &zone, 10);
	if (timestamp == TIME_MAX)
		goto bad;
	tz = strtol(zone, NULL, 10);
	if ((tz == LONG_MIN || tz == LONG_MAX) && errno == ERANGE)
		goto bad;
	v->s = xstrdup(show_date(timestamp, tz, &date_mode));
	v->value = timestamp;
	return;
 bad:
	v->s = xstrdup("");
	v->value = 0;
}

/* See grab_values */
static void grab_person(const char *who, struct atom_value *val, int deref, void *buf)
{
	int i;
	int wholen = strlen(who);
	const char *wholine = NULL;

	for (i = 0; i < used_atom_cnt; i++) {
		const char *name = used_atom[i].name;
		struct atom_value *v = &val[i];
		if (!!deref != (*name == '*'))
			continue;
		if (deref)
			name++;
		if (strncmp(who, name, wholen))
			continue;
		if (name[wholen] != 0 &&
		    strcmp(name + wholen, "name") &&
		    strcmp(name + wholen, "email") &&
		    !starts_with(name + wholen, "date"))
			continue;
		if (!wholine)
			wholine = find_wholine(who, wholen, buf);
		if (!wholine)
			return; /* no point looking for it */
		if (name[wholen] == 0)
			v->s = copy_line(wholine);
		else if (!strcmp(name + wholen, "name"))
			v->s = copy_name(wholine);
		else if (!strcmp(name + wholen, "email"))
			v->s = copy_email(wholine);
		else if (starts_with(name + wholen, "date"))
			grab_date(wholine, v, name);
	}

	/*
	 * For a tag or a commit object, if "creator" or "creatordate" is
	 * requested, do something special.
	 */
	if (strcmp(who, "tagger") && strcmp(who, "committer"))
		return; /* "author" for commit object is not wanted */
	if (!wholine)
		wholine = find_wholine(who, wholen, buf);
	if (!wholine)
		return;
	for (i = 0; i < used_atom_cnt; i++) {
		const char *name = used_atom[i].name;
		struct atom_value *v = &val[i];
		if (!!deref != (*name == '*'))
			continue;
		if (deref)
			name++;

		if (starts_with(name, "creatordate"))
			grab_date(wholine, v, name);
		else if (!strcmp(name, "creator"))
			v->s = copy_line(wholine);
	}
}

static void find_subpos(const char *buf,
			const char **sub, unsigned long *sublen,
			const char **body, unsigned long *bodylen,
			unsigned long *nonsiglen,
			const char **sig, unsigned long *siglen)
{
	const char *eol;
	/* skip past header until we hit empty line */
	while (*buf && *buf != '\n') {
		eol = strchrnul(buf, '\n');
		if (*eol)
			eol++;
		buf = eol;
	}
	/* skip any empty lines */
	while (*buf == '\n')
		buf++;

	/* parse signature first; we might not even have a subject line */
	*sig = buf + parse_signature(buf, strlen(buf));
	*siglen = strlen(*sig);

	/* subject is first non-empty line */
	*sub = buf;
	/* subject goes to first empty line */
	while (buf < *sig && *buf && *buf != '\n') {
		eol = strchrnul(buf, '\n');
		if (*eol)
			eol++;
		buf = eol;
	}
	*sublen = buf - *sub;
	/* drop trailing newline, if present */
	if (*sublen && (*sub)[*sublen - 1] == '\n')
		*sublen -= 1;

	/* skip any empty lines */
	while (*buf == '\n')
		buf++;
	*body = buf;
	*bodylen = strlen(buf);
	*nonsiglen = *sig - buf;
}

/*
 * If 'lines' is greater than 0, append that many lines from the given
 * 'buf' of length 'size' to the given strbuf.
 */
static void append_lines(struct strbuf *out, const char *buf, unsigned long size, int lines)
{
	int i;
	const char *sp, *eol;
	size_t len;

	sp = buf;

	for (i = 0; i < lines && sp < buf + size; i++) {
		if (i)
			strbuf_addstr(out, "\n    ");
		eol = memchr(sp, '\n', size - (sp - buf));
		len = eol ? eol - sp : size - (sp - buf);
		strbuf_add(out, sp, len);
		if (!eol)
			break;
		sp = eol + 1;
	}
}

/* See grab_values */
static void grab_sub_body_contents(struct atom_value *val, int deref, void *buf)
{
	int i;
	const char *subpos = NULL, *bodypos = NULL, *sigpos = NULL;
	unsigned long sublen = 0, bodylen = 0, nonsiglen = 0, siglen = 0;

	for (i = 0; i < used_atom_cnt; i++) {
		struct used_atom *atom = &used_atom[i];
		const char *name = atom->name;
		struct atom_value *v = &val[i];
		if (!!deref != (*name == '*'))
			continue;
		if (deref)
			name++;
		if (strcmp(name, "subject") &&
		    strcmp(name, "body") &&
		    !starts_with(name, "trailers") &&
		    !starts_with(name, "contents"))
			continue;
		if (!subpos)
			find_subpos(buf,
				    &subpos, &sublen,
				    &bodypos, &bodylen, &nonsiglen,
				    &sigpos, &siglen);

		if (atom->u.contents.option == C_SUB)
			v->s = copy_subject(subpos, sublen);
		else if (atom->u.contents.option == C_BODY_DEP)
			v->s = xmemdupz(bodypos, bodylen);
		else if (atom->u.contents.option == C_BODY)
			v->s = xmemdupz(bodypos, nonsiglen);
		else if (atom->u.contents.option == C_SIG)
			v->s = xmemdupz(sigpos, siglen);
		else if (atom->u.contents.option == C_LINES) {
			struct strbuf s = STRBUF_INIT;
			const char *contents_end = bodylen + bodypos - siglen;

			/*  Size is the length of the message after removing the signature */
			append_lines(&s, subpos, contents_end - subpos, atom->u.contents.nlines);
			v->s = strbuf_detach(&s, NULL);
		} else if (atom->u.contents.option == C_TRAILERS) {
			struct strbuf s = STRBUF_INIT;

			/* Format the trailer info according to the trailer_opts given */
			format_trailers_from_commit(&s, subpos, &atom->u.contents.trailer_opts);

			v->s = strbuf_detach(&s, NULL);
		} else if (atom->u.contents.option == C_BARE)
			v->s = xstrdup(subpos);
	}
}

/*
 * We want to have empty print-string for field requests
 * that do not apply (e.g. "authordate" for a tag object)
 */
static void fill_missing_values(struct atom_value *val)
{
	int i;
	for (i = 0; i < used_atom_cnt; i++) {
		struct atom_value *v = &val[i];
		if (v->s == NULL)
			v->s = xstrdup("");
	}
}

/*
 * val is a list of atom_value to hold returned values.  Extract
 * the values for atoms in used_atom array out of (obj, buf, sz).
 * when deref is false, (obj, buf, sz) is the object that is
 * pointed at by the ref itself; otherwise it is the object the
 * ref (which is a tag) refers to.
 */
static void grab_values(struct atom_value *val, int deref, struct object *obj, void *buf)
{
	switch (obj->type) {
	case OBJ_TAG:
		grab_tag_values(val, deref, obj);
		grab_sub_body_contents(val, deref, buf);
		grab_person("tagger", val, deref, buf);
		break;
	case OBJ_COMMIT:
		grab_commit_values(val, deref, obj);
		grab_sub_body_contents(val, deref, buf);
		grab_person("author", val, deref, buf);
		grab_person("committer", val, deref, buf);
		break;
	case OBJ_TREE:
		/* grab_tree_values(val, deref, obj, buf, sz); */
		break;
	case OBJ_BLOB:
		/* grab_blob_values(val, deref, obj, buf, sz); */
		break;
	default:
		die("Eh?  Object of type %d?", obj->type);
	}
}

static inline char *copy_advance(char *dst, const char *src)
{
	while (*src)
		*dst++ = *src++;
	return dst;
}

static const char *lstrip_ref_components(const char *refname, int len)
{
	long remaining = len;
	const char *start = xstrdup(refname);
	const char *to_free = start;

	if (len < 0) {
		int i;
		const char *p = refname;

		/* Find total no of '/' separated path-components */
		for (i = 0; p[i]; p[i] == '/' ? i++ : *p++)
			;
		/*
		 * The number of components we need to strip is now
		 * the total minus the components to be left (Plus one
		 * because we count the number of '/', but the number
		 * of components is one more than the no of '/').
		 */
		remaining = i + len + 1;
	}

	while (remaining > 0) {
		switch (*start++) {
		case '\0':
			free((char *)to_free);
			return xstrdup("");
		case '/':
			remaining--;
			break;
		}
	}

	start = xstrdup(start);
	free((char *)to_free);
	return start;
}

static const char *rstrip_ref_components(const char *refname, int len)
{
	long remaining = len;
	const char *start = xstrdup(refname);
	const char *to_free = start;

	if (len < 0) {
		int i;
		const char *p = refname;

		/* Find total no of '/' separated path-components */
		for (i = 0; p[i]; p[i] == '/' ? i++ : *p++)
			;
		/*
		 * The number of components we need to strip is now
		 * the total minus the components to be left (Plus one
		 * because we count the number of '/', but the number
		 * of components is one more than the no of '/').
		 */
		remaining = i + len + 1;
	}

	while (remaining-- > 0) {
		char *p = strrchr(start, '/');
		if (p == NULL) {
			free((char *)to_free);
			return xstrdup("");
		} else
			p[0] = '\0';
	}
	return start;
}

static const char *show_ref(struct refname_atom *atom, const char *refname)
{
	if (atom->option == R_SHORT)
		return shorten_unambiguous_ref(refname, warn_ambiguous_refs);
	else if (atom->option == R_LSTRIP)
		return lstrip_ref_components(refname, atom->lstrip);
	else if (atom->option == R_RSTRIP)
		return rstrip_ref_components(refname, atom->rstrip);
	else
		return xstrdup(refname);
}

static void fill_remote_ref_details(struct used_atom *atom, const char *refname,
				    struct branch *branch, const char **s)
{
	int num_ours, num_theirs;
	if (atom->u.remote_ref.option == RR_REF)
		*s = show_ref(&atom->u.remote_ref.refname, refname);
	else if (atom->u.remote_ref.option == RR_TRACK) {
		if (stat_tracking_info(branch, &num_ours, &num_theirs,
				       NULL, atom->u.remote_ref.push,
				       AHEAD_BEHIND_FULL) < 0) {
			*s = xstrdup(msgs.gone);
		} else if (!num_ours && !num_theirs)
			*s = xstrdup("");
		else if (!num_ours)
			*s = xstrfmt(msgs.behind, num_theirs);
		else if (!num_theirs)
			*s = xstrfmt(msgs.ahead, num_ours);
		else
			*s = xstrfmt(msgs.ahead_behind,
				     num_ours, num_theirs);
		if (!atom->u.remote_ref.nobracket && *s[0]) {
			const char *to_free = *s;
			*s = xstrfmt("[%s]", *s);
			free((void *)to_free);
		}
	} else if (atom->u.remote_ref.option == RR_TRACKSHORT) {
		if (stat_tracking_info(branch, &num_ours, &num_theirs,
				       NULL, atom->u.remote_ref.push,
				       AHEAD_BEHIND_FULL) < 0) {
			*s = xstrdup("");
			return;
		}
		if (!num_ours && !num_theirs)
			*s = xstrdup("=");
		else if (!num_ours)
			*s = xstrdup("<");
		else if (!num_theirs)
			*s = xstrdup(">");
		else
			*s = xstrdup("<>");
	} else if (atom->u.remote_ref.option == RR_REMOTE_NAME) {
		int explicit;
		const char *remote = atom->u.remote_ref.push ?
			pushremote_for_branch(branch, &explicit) :
			remote_for_branch(branch, &explicit);
		*s = xstrdup(explicit ? remote : "");
	} else if (atom->u.remote_ref.option == RR_REMOTE_REF) {
		const char *merge;

		merge = remote_ref_for_branch(branch, atom->u.remote_ref.push);
		*s = xstrdup(merge ? merge : "");
	} else
		BUG("unhandled RR_* enum");
}

char *get_head_description(void)
{
	struct strbuf desc = STRBUF_INIT;
	struct wt_status_state state;
	memset(&state, 0, sizeof(state));
	wt_status_get_state(the_repository, &state, 1);

	/*
	 * The ( character must be hard-coded and not part of a localizable
	 * string, since the description is used as a sort key and compared
	 * with ref names.
	 */
	strbuf_addch(&desc, '(');
	if (state.rebase_in_progress ||
	    state.rebase_interactive_in_progress) {
		if (state.branch)
			strbuf_addf(&desc, _("no branch, rebasing %s"),
				    state.branch);
		else
			strbuf_addf(&desc, _("no branch, rebasing detached HEAD %s"),
				    state.detached_from);
	} else if (state.bisect_in_progress)
		strbuf_addf(&desc, _("no branch, bisect started on %s"),
			    state.branch);
	else if (state.detached_from) {
		if (state.detached_at)
			strbuf_addstr(&desc, HEAD_DETACHED_AT);
		else
			strbuf_addstr(&desc, HEAD_DETACHED_FROM);
		strbuf_addstr(&desc, state.detached_from);
	}
	else
		strbuf_addstr(&desc, _("no branch"));
	strbuf_addch(&desc, ')');

	free(state.branch);
	free(state.onto);
	free(state.detached_from);
	return strbuf_detach(&desc, NULL);
}

static const char *get_symref(struct used_atom *atom, struct ref_array_item *ref)
{
	if (!ref->symref)
		return xstrdup("");
	else
		return show_ref(&atom->u.refname, ref->symref);
}

static const char *get_refname(struct used_atom *atom, struct ref_array_item *ref)
{
	if (ref->kind & FILTER_REFS_DETACHED_HEAD)
		return get_head_description();
	return show_ref(&atom->u.refname, ref->refname);
}

static int get_object(struct ref_array_item *ref, int deref, struct object **obj,
		      struct expand_data *oi, struct strbuf *err)
{
	/* parse_object_buffer() will set eaten to 0 if free() will be needed */
	int eaten = 1;
	if (oi->info.contentp) {
		/* We need to know that to use parse_object_buffer properly */
		oi->info.sizep = &oi->size;
		oi->info.typep = &oi->type;
	}
	if (oid_object_info_extended(the_repository, &oi->oid, &oi->info,
				     OBJECT_INFO_LOOKUP_REPLACE))
		return strbuf_addf_ret(err, -1, _("missing object %s for %s"),
				       oid_to_hex(&oi->oid), ref->refname);
	if (oi->info.disk_sizep && oi->disk_size < 0)
		BUG("Object size is less than zero.");

	if (oi->info.contentp) {
		*obj = parse_object_buffer(the_repository, &oi->oid, oi->type, oi->size, oi->content, &eaten);
		if (!obj) {
			if (!eaten)
				free(oi->content);
			return strbuf_addf_ret(err, -1, _("parse_object_buffer failed on %s for %s"),
					       oid_to_hex(&oi->oid), ref->refname);
		}
		grab_values(ref->value, deref, *obj, oi->content);
	}

	grab_common_values(ref->value, deref, oi);
	if (!eaten)
		free(oi->content);
	return 0;
}

static void populate_worktree_map(struct hashmap *map, struct worktree **worktrees)
{
	int i;

	for (i = 0; worktrees[i]; i++) {
		if (worktrees[i]->head_ref) {
			struct ref_to_worktree_entry *entry;
			entry = xmalloc(sizeof(*entry));
			entry->wt = worktrees[i];
			hashmap_entry_init(&entry->ent,
					strhash(worktrees[i]->head_ref));

			hashmap_add(map, &entry->ent);
		}
	}
}

static void lazy_init_worktree_map(void)
{
	if (ref_to_worktree_map.worktrees)
		return;

	ref_to_worktree_map.worktrees = get_worktrees(0);
	hashmap_init(&(ref_to_worktree_map.map), ref_to_worktree_map_cmpfnc, NULL, 0);
	populate_worktree_map(&(ref_to_worktree_map.map), ref_to_worktree_map.worktrees);
}

static char *get_worktree_path(const struct used_atom *atom, const struct ref_array_item *ref)
{
	struct hashmap_entry entry, *e;
	struct ref_to_worktree_entry *lookup_result;

	lazy_init_worktree_map();

	hashmap_entry_init(&entry, strhash(ref->refname));
	e = hashmap_get(&(ref_to_worktree_map.map), &entry, ref->refname);

	if (!e)
		return xstrdup("");

	lookup_result = container_of(e, struct ref_to_worktree_entry, ent);

	return xstrdup(lookup_result->wt->path);
}

/*
 * Parse the object referred by ref, and grab needed value.
 */
static int populate_value(struct ref_array_item *ref, struct strbuf *err)
{
	struct object *obj;
	int i;
	struct object_info empty = OBJECT_INFO_INIT;

	ref->value = xcalloc(used_atom_cnt, sizeof(struct atom_value));

	if (need_symref && (ref->flag & REF_ISSYMREF) && !ref->symref) {
		ref->symref = resolve_refdup(ref->refname, RESOLVE_REF_READING,
					     NULL, NULL);
		if (!ref->symref)
			ref->symref = xstrdup("");
	}

	/* Fill in specials first */
	for (i = 0; i < used_atom_cnt; i++) {
		struct used_atom *atom = &used_atom[i];
		const char *name = used_atom[i].name;
		struct atom_value *v = &ref->value[i];
		int deref = 0;
		const char *refname;
		struct branch *branch = NULL;

		v->handler = append_atom;
		v->atom = atom;

		if (*name == '*') {
			deref = 1;
			name++;
		}

		if (starts_with(name, "refname"))
			refname = get_refname(atom, ref);
		else if (!strcmp(name, "worktreepath")) {
			if (ref->kind == FILTER_REFS_BRANCHES)
				v->s = get_worktree_path(atom, ref);
			else
				v->s = xstrdup("");
			continue;
		}
		else if (starts_with(name, "symref"))
			refname = get_symref(atom, ref);
		else if (starts_with(name, "upstream")) {
			const char *branch_name;
			/* only local branches may have an upstream */
			if (!skip_prefix(ref->refname, "refs/heads/",
					 &branch_name)) {
				v->s = xstrdup("");
				continue;
			}
			branch = branch_get(branch_name);

			refname = branch_get_upstream(branch, NULL);
			if (refname)
				fill_remote_ref_details(atom, refname, branch, &v->s);
			else
				v->s = xstrdup("");
			continue;
		} else if (atom->u.remote_ref.push) {
			const char *branch_name;
			v->s = xstrdup("");
			if (!skip_prefix(ref->refname, "refs/heads/",
					 &branch_name))
				continue;
			branch = branch_get(branch_name);

			if (atom->u.remote_ref.push_remote)
				refname = NULL;
			else {
				refname = branch_get_push(branch, NULL);
				if (!refname)
					continue;
			}
			/* We will definitely re-init v->s on the next line. */
			free((char *)v->s);
			fill_remote_ref_details(atom, refname, branch, &v->s);
			continue;
		} else if (starts_with(name, "color:")) {
			v->s = xstrdup(atom->u.color);
			continue;
		} else if (!strcmp(name, "flag")) {
			char buf[256], *cp = buf;
			if (ref->flag & REF_ISSYMREF)
				cp = copy_advance(cp, ",symref");
			if (ref->flag & REF_ISPACKED)
				cp = copy_advance(cp, ",packed");
			if (cp == buf)
				v->s = xstrdup("");
			else {
				*cp = '\0';
				v->s = xstrdup(buf + 1);
			}
			continue;
		} else if (!deref && grab_objectname(name, &ref->objectname, v, atom)) {
			continue;
		} else if (!strcmp(name, "HEAD")) {
			if (atom->u.head && !strcmp(ref->refname, atom->u.head))
				v->s = xstrdup("*");
			else
				v->s = xstrdup(" ");
			continue;
		} else if (starts_with(name, "align")) {
			v->handler = align_atom_handler;
			v->s = xstrdup("");
			continue;
		} else if (!strcmp(name, "end")) {
			v->handler = end_atom_handler;
			v->s = xstrdup("");
			continue;
		} else if (starts_with(name, "if")) {
			const char *s;
			if (skip_prefix(name, "if:", &s))
				v->s = xstrdup(s);
			else
				v->s = xstrdup("");
			v->handler = if_atom_handler;
			continue;
		} else if (!strcmp(name, "then")) {
			v->handler = then_atom_handler;
			v->s = xstrdup("");
			continue;
		} else if (!strcmp(name, "else")) {
			v->handler = else_atom_handler;
			v->s = xstrdup("");
			continue;
		} else
			continue;

		if (!deref)
			v->s = xstrdup(refname);
		else
			v->s = xstrfmt("%s^{}", refname);
		free((char *)refname);
	}

	for (i = 0; i < used_atom_cnt; i++) {
		struct atom_value *v = &ref->value[i];
		if (v->s == NULL && used_atom[i].source == SOURCE_NONE)
			return strbuf_addf_ret(err, -1, _("missing object %s for %s"),
					       oid_to_hex(&ref->objectname), ref->refname);
	}

	if (need_tagged)
		oi.info.contentp = &oi.content;
	if (!memcmp(&oi.info, &empty, sizeof(empty)) &&
	    !memcmp(&oi_deref.info, &empty, sizeof(empty)))
		return 0;


	oi.oid = ref->objectname;
	if (get_object(ref, 0, &obj, &oi, err))
		return -1;

	/*
	 * If there is no atom that wants to know about tagged
	 * object, we are done.
	 */
	if (!need_tagged || (obj->type != OBJ_TAG))
		return 0;

	/*
	 * If it is a tag object, see if we use a value that derefs
	 * the object, and if we do grab the object it refers to.
	 */
	oi_deref.oid = *get_tagged_oid((struct tag *)obj);

	/*
	 * NEEDSWORK: This derefs tag only once, which
	 * is good to deal with chains of trust, but
	 * is not consistent with what deref_tag() does
	 * which peels the onion to the core.
	 */
	return get_object(ref, 1, &obj, &oi_deref, err);
}

/*
 * Given a ref, return the value for the atom.  This lazily gets value
 * out of the object by calling populate value.
 */
static int get_ref_atom_value(struct ref_array_item *ref, int atom,
			      struct atom_value **v, struct strbuf *err)
{
	if (!ref->value) {
		if (populate_value(ref, err))
			return -1;
		fill_missing_values(ref->value);
	}
	*v = &ref->value[atom];
	return 0;
}

/*
 * Return 1 if the refname matches one of the patterns, otherwise 0.
 * A pattern can be a literal prefix (e.g. a refname "refs/heads/master"
 * matches a pattern "refs/heads/mas") or a wildcard (e.g. the same ref
 * matches "refs/heads/mas*", too).
 */
static int match_pattern(const struct ref_filter *filter, const char *refname)
{
	const char **patterns = filter->name_patterns;
	unsigned flags = 0;

	if (filter->ignore_case)
		flags |= WM_CASEFOLD;

	/*
	 * When no '--format' option is given we need to skip the prefix
	 * for matching refs of tags and branches.
	 */
	(void)(skip_prefix(refname, "refs/tags/", &refname) ||
	       skip_prefix(refname, "refs/heads/", &refname) ||
	       skip_prefix(refname, "refs/remotes/", &refname) ||
	       skip_prefix(refname, "refs/", &refname));

	for (; *patterns; patterns++) {
		if (!wildmatch(*patterns, refname, flags))
			return 1;
	}
	return 0;
}

/*
 * Return 1 if the refname matches one of the patterns, otherwise 0.
 * A pattern can be path prefix (e.g. a refname "refs/heads/master"
 * matches a pattern "refs/heads/" but not "refs/heads/m") or a
 * wildcard (e.g. the same ref matches "refs/heads/m*", too).
 */
static int match_name_as_path(const struct ref_filter *filter, const char *refname)
{
	const char **pattern = filter->name_patterns;
	int namelen = strlen(refname);
	unsigned flags = WM_PATHNAME;

	if (filter->ignore_case)
		flags |= WM_CASEFOLD;

	for (; *pattern; pattern++) {
		const char *p = *pattern;
		int plen = strlen(p);

		if ((plen <= namelen) &&
		    !strncmp(refname, p, plen) &&
		    (refname[plen] == '\0' ||
		     refname[plen] == '/' ||
		     p[plen-1] == '/'))
			return 1;
		if (!wildmatch(p, refname, flags))
			return 1;
	}
	return 0;
}

/* Return 1 if the refname matches one of the patterns, otherwise 0. */
static int filter_pattern_match(struct ref_filter *filter, const char *refname)
{
	if (!*filter->name_patterns)
		return 1; /* No pattern always matches */
	if (filter->match_as_path)
		return match_name_as_path(filter, refname);
	return match_pattern(filter, refname);
}

static int qsort_strcmp(const void *va, const void *vb)
{
	const char *a = *(const char **)va;
	const char *b = *(const char **)vb;

	return strcmp(a, b);
}

static void find_longest_prefixes_1(struct string_list *out,
				  struct strbuf *prefix,
				  const char **patterns, size_t nr)
{
	size_t i;

	for (i = 0; i < nr; i++) {
		char c = patterns[i][prefix->len];
		if (!c || is_glob_special(c)) {
			string_list_append(out, prefix->buf);
			return;
		}
	}

	i = 0;
	while (i < nr) {
		size_t end;

		/*
		* Set "end" to the index of the element _after_ the last one
		* in our group.
		*/
		for (end = i + 1; end < nr; end++) {
			if (patterns[i][prefix->len] != patterns[end][prefix->len])
				break;
		}

		strbuf_addch(prefix, patterns[i][prefix->len]);
		find_longest_prefixes_1(out, prefix, patterns + i, end - i);
		strbuf_setlen(prefix, prefix->len - 1);

		i = end;
	}
}

static void find_longest_prefixes(struct string_list *out,
				  const char **patterns)
{
	struct argv_array sorted = ARGV_ARRAY_INIT;
	struct strbuf prefix = STRBUF_INIT;

	argv_array_pushv(&sorted, patterns);
	QSORT(sorted.argv, sorted.argc, qsort_strcmp);

	find_longest_prefixes_1(out, &prefix, sorted.argv, sorted.argc);

	argv_array_clear(&sorted);
	strbuf_release(&prefix);
}

/*
 * This is the same as for_each_fullref_in(), but it tries to iterate
 * only over the patterns we'll care about. Note that it _doesn't_ do a full
 * pattern match, so the callback still has to match each ref individually.
 */
static int for_each_fullref_in_pattern(struct ref_filter *filter,
				       each_ref_fn cb,
				       void *cb_data,
				       int broken)
{
	struct string_list prefixes = STRING_LIST_INIT_DUP;
	struct string_list_item *prefix;
	int ret;

	if (!filter->match_as_path) {
		/*
		 * in this case, the patterns are applied after
		 * prefixes like "refs/heads/" etc. are stripped off,
		 * so we have to look at everything:
		 */
		return for_each_fullref_in("", cb, cb_data, broken);
	}

	if (filter->ignore_case) {
		/*
		 * we can't handle case-insensitive comparisons,
		 * so just return everything and let the caller
		 * sort it out.
		 */
		return for_each_fullref_in("", cb, cb_data, broken);
	}

	if (!filter->name_patterns[0]) {
		/* no patterns; we have to look at everything */
		return for_each_fullref_in("", cb, cb_data, broken);
	}

	find_longest_prefixes(&prefixes, filter->name_patterns);

	for_each_string_list_item(prefix, &prefixes) {
		ret = for_each_fullref_in(prefix->string, cb, cb_data, broken);
		if (ret)
			break;
	}

	string_list_clear(&prefixes, 0);
	return ret;
}

/*
 * Given a ref (sha1, refname), check if the ref belongs to the array
 * of sha1s. If the given ref is a tag, check if the given tag points
 * at one of the sha1s in the given sha1 array.
 * the given sha1_array.
 * NEEDSWORK:
 * 1. Only a single level of inderection is obtained, we might want to
 * change this to account for multiple levels (e.g. annotated tags
 * pointing to annotated tags pointing to a commit.)
 * 2. As the refs are cached we might know what refname peels to without
 * the need to parse the object via parse_object(). peel_ref() might be a
 * more efficient alternative to obtain the pointee.
 */
static const struct object_id *match_points_at(struct oid_array *points_at,
					       const struct object_id *oid,
					       const char *refname)
{
	const struct object_id *tagged_oid = NULL;
	struct object *obj;

	if (oid_array_lookup(points_at, oid) >= 0)
		return oid;
	obj = parse_object(the_repository, oid);
	if (!obj)
		die(_("malformed object at '%s'"), refname);
	if (obj->type == OBJ_TAG)
		tagged_oid = get_tagged_oid((struct tag *)obj);
	if (tagged_oid && oid_array_lookup(points_at, tagged_oid) >= 0)
		return tagged_oid;
	return NULL;
}

/*
 * Allocate space for a new ref_array_item and copy the name and oid to it.
 *
 * Callers can then fill in other struct members at their leisure.
 */
static struct ref_array_item *new_ref_array_item(const char *refname,
						 const struct object_id *oid)
{
	struct ref_array_item *ref;

	FLEX_ALLOC_STR(ref, refname, refname);
	oidcpy(&ref->objectname, oid);

	return ref;
}

struct ref_array_item *ref_array_push(struct ref_array *array,
				      const char *refname,
				      const struct object_id *oid)
{
	struct ref_array_item *ref = new_ref_array_item(refname, oid);

	ALLOC_GROW(array->items, array->nr + 1, array->alloc);
	array->items[array->nr++] = ref;

	return ref;
}

static int ref_kind_from_refname(const char *refname)
{
	unsigned int i;

	static struct {
		const char *prefix;
		unsigned int kind;
	} ref_kind[] = {
		{ "refs/heads/" , FILTER_REFS_BRANCHES },
		{ "refs/remotes/" , FILTER_REFS_REMOTES },
		{ "refs/tags/", FILTER_REFS_TAGS}
	};

	if (!strcmp(refname, "HEAD"))
		return FILTER_REFS_DETACHED_HEAD;

	for (i = 0; i < ARRAY_SIZE(ref_kind); i++) {
		if (starts_with(refname, ref_kind[i].prefix))
			return ref_kind[i].kind;
	}

	return FILTER_REFS_OTHERS;
}

static int filter_ref_kind(struct ref_filter *filter, const char *refname)
{
	if (filter->kind == FILTER_REFS_BRANCHES ||
	    filter->kind == FILTER_REFS_REMOTES ||
	    filter->kind == FILTER_REFS_TAGS)
		return filter->kind;
	return ref_kind_from_refname(refname);
}

struct ref_filter_cbdata {
	struct ref_array *array;
	struct ref_filter *filter;
	struct contains_cache contains_cache;
	struct contains_cache no_contains_cache;
};

/*
 * A call-back given to for_each_ref().  Filter refs and keep them for
 * later object processing.
 */
static int ref_filter_handler(const char *refname, const struct object_id *oid, int flag, void *cb_data)
{
	struct ref_filter_cbdata *ref_cbdata = cb_data;
	struct ref_filter *filter = ref_cbdata->filter;
	struct ref_array_item *ref;
	struct commit *commit = NULL;
	unsigned int kind;

	if (flag & REF_BAD_NAME) {
		warning(_("ignoring ref with broken name %s"), refname);
		return 0;
	}

	if (flag & REF_ISBROKEN) {
		warning(_("ignoring broken ref %s"), refname);
		return 0;
	}

	/* Obtain the current ref kind from filter_ref_kind() and ignore unwanted refs. */
	kind = filter_ref_kind(filter, refname);
	if (!(kind & filter->kind))
		return 0;

	if (!filter_pattern_match(filter, refname))
		return 0;

	if (filter->points_at.nr && !match_points_at(&filter->points_at, oid, refname))
		return 0;

	/*
	 * A merge filter is applied on refs pointing to commits. Hence
	 * obtain the commit using the 'oid' available and discard all
	 * non-commits early. The actual filtering is done later.
	 */
	if (filter->merge_commit || filter->with_commit || filter->no_commit || filter->verbose) {
		commit = lookup_commit_reference_gently(the_repository, oid,
							1);
		if (!commit)
			return 0;
		/* We perform the filtering for the '--contains' option... */
		if (filter->with_commit &&
		    !commit_contains(filter, commit, filter->with_commit, &ref_cbdata->contains_cache))
			return 0;
		/* ...or for the `--no-contains' option */
		if (filter->no_commit &&
		    commit_contains(filter, commit, filter->no_commit, &ref_cbdata->no_contains_cache))
			return 0;
	}

	/*
	 * We do not open the object yet; sort may only need refname
	 * to do its job and the resulting list may yet to be pruned
	 * by maxcount logic.
	 */
	ref = ref_array_push(ref_cbdata->array, refname, oid);
	ref->commit = commit;
	ref->flag = flag;
	ref->kind = kind;

	return 0;
}

/*  Free memory allocated for a ref_array_item */
static void free_array_item(struct ref_array_item *item)
{
	free((char *)item->symref);
	if (item->value) {
		int i;
		for (i = 0; i < used_atom_cnt; i++)
			free((char *)item->value[i].s);
		free(item->value);
	}
	free(item);
}

/* Free all memory allocated for ref_array */
void ref_array_clear(struct ref_array *array)
{
	int i;

	for (i = 0; i < array->nr; i++)
		free_array_item(array->items[i]);
	FREE_AND_NULL(array->items);
	array->nr = array->alloc = 0;

	for (i = 0; i < used_atom_cnt; i++)
		free((char *)used_atom[i].name);
	FREE_AND_NULL(used_atom);
	used_atom_cnt = 0;

	if (ref_to_worktree_map.worktrees) {
		hashmap_free_entries(&(ref_to_worktree_map.map),
					struct ref_to_worktree_entry, ent);
		free_worktrees(ref_to_worktree_map.worktrees);
		ref_to_worktree_map.worktrees = NULL;
	}
}

static void do_merge_filter(struct ref_filter_cbdata *ref_cbdata)
{
	struct rev_info revs;
	int i, old_nr;
	struct ref_filter *filter = ref_cbdata->filter;
	struct ref_array *array = ref_cbdata->array;
	struct commit **to_clear = xcalloc(sizeof(struct commit *), array->nr);

	repo_init_revisions(the_repository, &revs, NULL);

	for (i = 0; i < array->nr; i++) {
		struct ref_array_item *item = array->items[i];
		add_pending_object(&revs, &item->commit->object, item->refname);
		to_clear[i] = item->commit;
	}

	filter->merge_commit->object.flags |= UNINTERESTING;
	add_pending_object(&revs, &filter->merge_commit->object, "");

	revs.limited = 1;
	if (prepare_revision_walk(&revs))
		die(_("revision walk setup failed"));

	old_nr = array->nr;
	array->nr = 0;

	for (i = 0; i < old_nr; i++) {
		struct ref_array_item *item = array->items[i];
		struct commit *commit = item->commit;

		int is_merged = !!(commit->object.flags & UNINTERESTING);

		if (is_merged == (filter->merge == REF_FILTER_MERGED_INCLUDE))
			array->items[array->nr++] = array->items[i];
		else
			free_array_item(item);
	}

	clear_commit_marks_many(old_nr, to_clear, ALL_REV_FLAGS);
	clear_commit_marks(filter->merge_commit, ALL_REV_FLAGS);
	free(to_clear);
}

/*
 * API for filtering a set of refs. Based on the type of refs the user
 * has requested, we iterate through those refs and apply filters
 * as per the given ref_filter structure and finally store the
 * filtered refs in the ref_array structure.
 */
int filter_refs(struct ref_array *array, struct ref_filter *filter, unsigned int type)
{
	struct ref_filter_cbdata ref_cbdata;
	int ret = 0;
	unsigned int broken = 0;

	ref_cbdata.array = array;
	ref_cbdata.filter = filter;

	if (type & FILTER_REFS_INCLUDE_BROKEN)
		broken = 1;
	filter->kind = type & FILTER_REFS_KIND_MASK;

	init_contains_cache(&ref_cbdata.contains_cache);
	init_contains_cache(&ref_cbdata.no_contains_cache);

	/*  Simple per-ref filtering */
	if (!filter->kind)
		die("filter_refs: invalid type");
	else {
		/*
		 * For common cases where we need only branches or remotes or tags,
		 * we only iterate through those refs. If a mix of refs is needed,
		 * we iterate over all refs and filter out required refs with the help
		 * of filter_ref_kind().
		 */
		if (filter->kind == FILTER_REFS_BRANCHES)
			ret = for_each_fullref_in("refs/heads/", ref_filter_handler, &ref_cbdata, broken);
		else if (filter->kind == FILTER_REFS_REMOTES)
			ret = for_each_fullref_in("refs/remotes/", ref_filter_handler, &ref_cbdata, broken);
		else if (filter->kind == FILTER_REFS_TAGS)
			ret = for_each_fullref_in("refs/tags/", ref_filter_handler, &ref_cbdata, broken);
		else if (filter->kind & FILTER_REFS_ALL)
			ret = for_each_fullref_in_pattern(filter, ref_filter_handler, &ref_cbdata, broken);
		if (!ret && (filter->kind & FILTER_REFS_DETACHED_HEAD))
			head_ref(ref_filter_handler, &ref_cbdata);
	}

	clear_contains_cache(&ref_cbdata.contains_cache);
	clear_contains_cache(&ref_cbdata.no_contains_cache);

	/*  Filters that need revision walking */
	if (filter->merge_commit)
		do_merge_filter(&ref_cbdata);

	return ret;
}

static int cmp_ref_sorting(struct ref_sorting *s, struct ref_array_item *a, struct ref_array_item *b)
{
	struct atom_value *va, *vb;
	int cmp;
	cmp_type cmp_type = used_atom[s->atom].type;
	int (*cmp_fn)(const char *, const char *);
	struct strbuf err = STRBUF_INIT;

	if (get_ref_atom_value(a, s->atom, &va, &err))
		die("%s", err.buf);
	if (get_ref_atom_value(b, s->atom, &vb, &err))
		die("%s", err.buf);
	strbuf_release(&err);
	cmp_fn = s->ignore_case ? strcasecmp : strcmp;
	if (s->version)
		cmp = versioncmp(va->s, vb->s);
	else if (cmp_type == FIELD_STR)
		cmp = cmp_fn(va->s, vb->s);
	else {
		if (va->value < vb->value)
			cmp = -1;
		else if (va->value == vb->value)
			cmp = cmp_fn(a->refname, b->refname);
		else
			cmp = 1;
	}

	return (s->reverse) ? -cmp : cmp;
}

static int compare_refs(const void *a_, const void *b_, void *ref_sorting)
{
	struct ref_array_item *a = *((struct ref_array_item **)a_);
	struct ref_array_item *b = *((struct ref_array_item **)b_);
	struct ref_sorting *s;

	for (s = ref_sorting; s; s = s->next) {
		int cmp = cmp_ref_sorting(s, a, b);
		if (cmp)
			return cmp;
	}
	return 0;
}

void ref_array_sort(struct ref_sorting *sorting, struct ref_array *array)
{
	QSORT_S(array->items, array->nr, compare_refs, sorting);
}

static void append_literal(const char *cp, const char *ep, struct ref_formatting_state *state)
{
	struct strbuf *s = &state->stack->output;

	while (*cp && (!ep || cp < ep)) {
		if (*cp == '%') {
			if (cp[1] == '%')
				cp++;
			else {
				int ch = hex2chr(cp + 1);
				if (0 <= ch) {
					strbuf_addch(s, ch);
					cp += 3;
					continue;
				}
			}
		}
		strbuf_addch(s, *cp);
		cp++;
	}
}

int format_ref_array_item(struct ref_array_item *info,
			   const struct ref_format *format,
			   struct strbuf *final_buf,
			   struct strbuf *error_buf)
{
	const char *cp, *sp, *ep;
	struct ref_formatting_state state = REF_FORMATTING_STATE_INIT;

	state.quote_style = format->quote_style;
	push_stack_element(&state.stack);

	for (cp = format->format; *cp && (sp = find_next(cp)); cp = ep + 1) {
		struct atom_value *atomv;
		int pos;

		ep = strchr(sp, ')');
		if (cp < sp)
			append_literal(cp, sp, &state);
		pos = parse_ref_filter_atom(format, sp + 2, ep, error_buf);
		if (pos < 0 || get_ref_atom_value(info, pos, &atomv, error_buf) ||
		    atomv->handler(atomv, &state, error_buf)) {
			pop_stack_element(&state.stack);
			return -1;
		}
	}
	if (*cp) {
		sp = cp + strlen(cp);
		append_literal(cp, sp, &state);
	}
	if (format->need_color_reset_at_eol) {
		struct atom_value resetv;
		resetv.s = GIT_COLOR_RESET;
		if (append_atom(&resetv, &state, error_buf)) {
			pop_stack_element(&state.stack);
			return -1;
		}
	}
	if (state.stack->prev) {
		pop_stack_element(&state.stack);
		return strbuf_addf_ret(error_buf, -1, _("format: %%(end) atom missing"));
	}
	strbuf_addbuf(final_buf, &state.stack->output);
	pop_stack_element(&state.stack);
	return 0;
}

void show_ref_array_item(struct ref_array_item *info,
			 const struct ref_format *format)
{
	struct strbuf final_buf = STRBUF_INIT;
	struct strbuf error_buf = STRBUF_INIT;

	if (format_ref_array_item(info, format, &final_buf, &error_buf))
		die("%s", error_buf.buf);
	fwrite(final_buf.buf, 1, final_buf.len, stdout);
	strbuf_release(&error_buf);
	strbuf_release(&final_buf);
	putchar('\n');
}

void pretty_print_ref(const char *name, const struct object_id *oid,
		      const struct ref_format *format)
{
	struct ref_array_item *ref_item;
	ref_item = new_ref_array_item(name, oid);
	ref_item->kind = ref_kind_from_refname(name);
	show_ref_array_item(ref_item, format);
	free_array_item(ref_item);
}

static int parse_sorting_atom(const char *atom)
{
	/*
	 * This parses an atom using a dummy ref_format, since we don't
	 * actually care about the formatting details.
	 */
	struct ref_format dummy = REF_FORMAT_INIT;
	const char *end = atom + strlen(atom);
	struct strbuf err = STRBUF_INIT;
	int res = parse_ref_filter_atom(&dummy, atom, end, &err);
	if (res < 0)
		die("%s", err.buf);
	strbuf_release(&err);
	return res;
}

/*  If no sorting option is given, use refname to sort as default */
struct ref_sorting *ref_default_sorting(void)
{
	static const char cstr_name[] = "refname";

	struct ref_sorting *sorting = xcalloc(1, sizeof(*sorting));

	sorting->next = NULL;
	sorting->atom = parse_sorting_atom(cstr_name);
	return sorting;
}

void parse_ref_sorting(struct ref_sorting **sorting_tail, const char *arg)
{
	struct ref_sorting *s;

	s = xcalloc(1, sizeof(*s));
	s->next = *sorting_tail;
	*sorting_tail = s;

	if (*arg == '-') {
		s->reverse = 1;
		arg++;
	}
	if (skip_prefix(arg, "version:", &arg) ||
	    skip_prefix(arg, "v:", &arg))
		s->version = 1;
	s->atom = parse_sorting_atom(arg);
}

int parse_opt_ref_sorting(const struct option *opt, const char *arg, int unset)
{
	/*
	 * NEEDSWORK: We should probably clear the list in this case, but we've
	 * already munged the global used_atoms list, which would need to be
	 * undone.
	 */
	BUG_ON_OPT_NEG(unset);

	parse_ref_sorting(opt->value, arg);
	return 0;
}

int parse_opt_merge_filter(const struct option *opt, const char *arg, int unset)
{
	struct ref_filter *rf = opt->value;
	struct object_id oid;
	int no_merged = starts_with(opt->long_name, "no");

	BUG_ON_OPT_NEG(unset);

	if (rf->merge) {
		if (no_merged) {
			return error(_("option `%s' is incompatible with --merged"),
				     opt->long_name);
		} else {
			return error(_("option `%s' is incompatible with --no-merged"),
				     opt->long_name);
		}
	}

	rf->merge = no_merged
		? REF_FILTER_MERGED_OMIT
		: REF_FILTER_MERGED_INCLUDE;

	if (get_oid(arg, &oid))
		die(_("malformed object name %s"), arg);

	rf->merge_commit = lookup_commit_reference_gently(the_repository,
							  &oid, 0);
	if (!rf->merge_commit)
		return error(_("option `%s' must point to a commit"), opt->long_name);

	return 0;
}