summaryrefslogtreecommitdiff
path: root/builtin/name-rev.c
blob: 725dd04519133595dc212ce6c68e511b07c6b92a (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
#include "builtin.h"
#include "cache.h"
#include "repository.h"
#include "config.h"
#include "commit.h"
#include "tag.h"
#include "refs.h"
#include "parse-options.h"
#include "prio-queue.h"
#include "sha1-lookup.h"
#include "commit-slab.h"

/*
 * One day.  See the 'name a rev shortly after epoch' test in t6120 when
 * changing this value
 */
#define CUTOFF_DATE_SLOP 86400

struct rev_name {
	char *tip_name;
	timestamp_t taggerdate;
	int generation;
	int distance;
	int from_tag;
};

define_commit_slab(commit_rev_name, struct rev_name);

static timestamp_t cutoff = TIME_MAX;
static struct commit_rev_name rev_names;

/* How many generations are maximally preferred over _one_ merge traversal? */
#define MERGE_TRAVERSAL_WEIGHT 65535

static int is_valid_rev_name(const struct rev_name *name)
{
	return name && (name->generation || name->tip_name);
}

static struct rev_name *get_commit_rev_name(const struct commit *commit)
{
	struct rev_name *name = commit_rev_name_peek(&rev_names, commit);

	return is_valid_rev_name(name) ? name : NULL;
}

static int is_better_name(struct rev_name *name,
			  timestamp_t taggerdate,
			  int distance,
			  int from_tag)
{
	/*
	 * When comparing names based on tags, prefer names
	 * based on the older tag, even if it is farther away.
	 */
	if (from_tag && name->from_tag)
		return (name->taggerdate > taggerdate ||
			(name->taggerdate == taggerdate &&
			 name->distance > distance));

	/*
	 * We know that at least one of them is a non-tag at this point.
	 * favor a tag over a non-tag.
	 */
	if (name->from_tag != from_tag)
		return from_tag;

	/*
	 * We are now looking at two non-tags.  Tiebreak to favor
	 * shorter hops.
	 */
	if (name->distance != distance)
		return name->distance > distance;

	/* ... or tiebreak to favor older date */
	if (name->taggerdate != taggerdate)
		return name->taggerdate > taggerdate;

	/* keep the current one if we cannot decide */
	return 0;
}

static struct rev_name *create_or_update_name(struct commit *commit,
					      timestamp_t taggerdate,
					      int generation, int distance,
					      int from_tag)
{
	struct rev_name *name = commit_rev_name_at(&rev_names, commit);

	if (is_valid_rev_name(name)) {
		if (!is_better_name(name, taggerdate, distance, from_tag))
			return NULL;

		/*
		 * This string might still be shared with ancestors
		 * (generation > 0).  We can release it here regardless,
		 * because the new name that has just won will be better
		 * for them as well, so name_rev() will replace these
		 * stale pointers when it processes the parents.
		 */
		if (!name->generation)
			free(name->tip_name);
	}

	name->taggerdate = taggerdate;
	name->generation = generation;
	name->distance = distance;
	name->from_tag = from_tag;

	return name;
}

static char *get_parent_name(const struct rev_name *name, int parent_number)
{
	struct strbuf sb = STRBUF_INIT;
	size_t len;

	strip_suffix(name->tip_name, "^0", &len);
	if (name->generation > 0) {
		strbuf_grow(&sb, len +
			    1 + decimal_width(name->generation) +
			    1 + decimal_width(parent_number));
		strbuf_addf(&sb, "%.*s~%d^%d", (int)len, name->tip_name,
			    name->generation, parent_number);
	} else {
		strbuf_grow(&sb, len +
			    1 + decimal_width(parent_number));
		strbuf_addf(&sb, "%.*s^%d", (int)len, name->tip_name,
			    parent_number);
	}
	return strbuf_detach(&sb, NULL);
}

static void name_rev(struct commit *start_commit,
		const char *tip_name, timestamp_t taggerdate,
		int from_tag, int deref)
{
	struct prio_queue queue;
	struct commit *commit;
	struct commit **parents_to_queue = NULL;
	size_t parents_to_queue_nr, parents_to_queue_alloc = 0;
	struct rev_name *start_name;

	parse_commit(start_commit);
	if (start_commit->date < cutoff)
		return;

	start_name = create_or_update_name(start_commit, taggerdate, 0, 0,
					   from_tag);
	if (!start_name)
		return;
	if (deref)
		start_name->tip_name = xstrfmt("%s^0", tip_name);
	else
		start_name->tip_name = xstrdup(tip_name);

	memset(&queue, 0, sizeof(queue)); /* Use the prio_queue as LIFO */
	prio_queue_put(&queue, start_commit);

	while ((commit = prio_queue_get(&queue))) {
		struct rev_name *name = get_commit_rev_name(commit);
		struct commit_list *parents;
		int parent_number = 1;

		parents_to_queue_nr = 0;

		for (parents = commit->parents;
				parents;
				parents = parents->next, parent_number++) {
			struct commit *parent = parents->item;
			struct rev_name *parent_name;
			int generation, distance;

			parse_commit(parent);
			if (parent->date < cutoff)
				continue;

			if (parent_number > 1) {
				generation = 0;
				distance = name->distance + MERGE_TRAVERSAL_WEIGHT;
			} else {
				generation = name->generation + 1;
				distance = name->distance + 1;
			}

			parent_name = create_or_update_name(parent, taggerdate,
							    generation,
							    distance, from_tag);
			if (parent_name) {
				if (parent_number > 1)
					parent_name->tip_name =
						get_parent_name(name,
								parent_number);
				else
					parent_name->tip_name = name->tip_name;
				ALLOC_GROW(parents_to_queue,
					   parents_to_queue_nr + 1,
					   parents_to_queue_alloc);
				parents_to_queue[parents_to_queue_nr] = parent;
				parents_to_queue_nr++;
			}
		}

		/* The first parent must come out first from the prio_queue */
		while (parents_to_queue_nr)
			prio_queue_put(&queue,
				       parents_to_queue[--parents_to_queue_nr]);
	}

	clear_prio_queue(&queue);
	free(parents_to_queue);
}

static int subpath_matches(const char *path, const char *filter)
{
	const char *subpath = path;

	while (subpath) {
		if (!wildmatch(filter, subpath, 0))
			return subpath - path;
		subpath = strchr(subpath, '/');
		if (subpath)
			subpath++;
	}
	return -1;
}

static const char *name_ref_abbrev(const char *refname, int shorten_unambiguous)
{
	if (shorten_unambiguous)
		refname = shorten_unambiguous_ref(refname, 0);
	else if (skip_prefix(refname, "refs/heads/", &refname))
		; /* refname already advanced */
	else
		skip_prefix(refname, "refs/", &refname);
	return refname;
}

struct name_ref_data {
	int tags_only;
	int name_only;
	struct string_list ref_filters;
	struct string_list exclude_filters;
};

static struct tip_table {
	struct tip_table_entry {
		struct object_id oid;
		const char *refname;
		struct commit *commit;
		timestamp_t taggerdate;
		unsigned int from_tag:1;
		unsigned int deref:1;
	} *table;
	int nr;
	int alloc;
	int sorted;
} tip_table;

static void add_to_tip_table(const struct object_id *oid, const char *refname,
			     int shorten_unambiguous, struct commit *commit,
			     timestamp_t taggerdate, int from_tag, int deref)
{
	refname = name_ref_abbrev(refname, shorten_unambiguous);

	ALLOC_GROW(tip_table.table, tip_table.nr + 1, tip_table.alloc);
	oidcpy(&tip_table.table[tip_table.nr].oid, oid);
	tip_table.table[tip_table.nr].refname = xstrdup(refname);
	tip_table.table[tip_table.nr].commit = commit;
	tip_table.table[tip_table.nr].taggerdate = taggerdate;
	tip_table.table[tip_table.nr].from_tag = from_tag;
	tip_table.table[tip_table.nr].deref = deref;
	tip_table.nr++;
	tip_table.sorted = 0;
}

static int tipcmp(const void *a_, const void *b_)
{
	const struct tip_table_entry *a = a_, *b = b_;
	return oidcmp(&a->oid, &b->oid);
}

static int cmp_by_tag_and_age(const void *a_, const void *b_)
{
	const struct tip_table_entry *a = a_, *b = b_;
	int cmp;

	/* Prefer tags. */
	cmp = b->from_tag - a->from_tag;
	if (cmp)
		return cmp;

	/* Older is better. */
	if (a->taggerdate < b->taggerdate)
		return -1;
	return a->taggerdate != b->taggerdate;
}

static int name_ref(const char *path, const struct object_id *oid, int flags, void *cb_data)
{
	struct object *o = parse_object(the_repository, oid);
	struct name_ref_data *data = cb_data;
	int can_abbreviate_output = data->tags_only && data->name_only;
	int deref = 0;
	int from_tag = 0;
	struct commit *commit = NULL;
	timestamp_t taggerdate = TIME_MAX;

	if (data->tags_only && !starts_with(path, "refs/tags/"))
		return 0;

	if (data->exclude_filters.nr) {
		struct string_list_item *item;

		for_each_string_list_item(item, &data->exclude_filters) {
			if (subpath_matches(path, item->string) >= 0)
				return 0;
		}
	}

	if (data->ref_filters.nr) {
		struct string_list_item *item;
		int matched = 0;

		/* See if any of the patterns match. */
		for_each_string_list_item(item, &data->ref_filters) {
			/*
			 * Check all patterns even after finding a match, so
			 * that we can see if a match with a subpath exists.
			 * When a user asked for 'refs/tags/v*' and 'v1.*',
			 * both of which match, the user is showing her
			 * willingness to accept a shortened output by having
			 * the 'v1.*' in the acceptable refnames, so we
			 * shouldn't stop when seeing 'refs/tags/v1.4' matches
			 * 'refs/tags/v*'.  We should show it as 'v1.4'.
			 */
			switch (subpath_matches(path, item->string)) {
			case -1: /* did not match */
				break;
			case 0: /* matched fully */
				matched = 1;
				break;
			default: /* matched subpath */
				matched = 1;
				can_abbreviate_output = 1;
				break;
			}
		}

		/* If none of the patterns matched, stop now */
		if (!matched)
			return 0;
	}

	while (o && o->type == OBJ_TAG) {
		struct tag *t = (struct tag *) o;
		if (!t->tagged)
			break; /* broken repository */
		o = parse_object(the_repository, &t->tagged->oid);
		deref = 1;
		taggerdate = t->date;
	}
	if (o && o->type == OBJ_COMMIT) {
		commit = (struct commit *)o;
		from_tag = starts_with(path, "refs/tags/");
		if (taggerdate == TIME_MAX)
			taggerdate = commit->date;
	}

	add_to_tip_table(oid, path, can_abbreviate_output, commit, taggerdate,
			 from_tag, deref);
	return 0;
}

static void name_tips(void)
{
	int i;

	/*
	 * Try to set better names first, so that worse ones spread
	 * less.
	 */
	QSORT(tip_table.table, tip_table.nr, cmp_by_tag_and_age);
	for (i = 0; i < tip_table.nr; i++) {
		struct tip_table_entry *e = &tip_table.table[i];
		if (e->commit) {
			name_rev(e->commit, e->refname, e->taggerdate,
				 e->from_tag, e->deref);
		}
	}
}

static const unsigned char *nth_tip_table_ent(size_t ix, void *table_)
{
	struct tip_table_entry *table = table_;
	return table[ix].oid.hash;
}

static const char *get_exact_ref_match(const struct object *o)
{
	int found;

	if (!tip_table.table || !tip_table.nr)
		return NULL;

	if (!tip_table.sorted) {
		QSORT(tip_table.table, tip_table.nr, tipcmp);
		tip_table.sorted = 1;
	}

	found = sha1_pos(o->oid.hash, tip_table.table, tip_table.nr,
			 nth_tip_table_ent);
	if (0 <= found)
		return tip_table.table[found].refname;
	return NULL;
}

/* may return a constant string or use "buf" as scratch space */
static const char *get_rev_name(const struct object *o, struct strbuf *buf)
{
	struct rev_name *n;
	const struct commit *c;

	if (o->type != OBJ_COMMIT)
		return get_exact_ref_match(o);
	c = (const struct commit *) o;
	n = get_commit_rev_name(c);
	if (!n)
		return NULL;

	if (!n->generation)
		return n->tip_name;
	else {
		strbuf_reset(buf);
		strbuf_addstr(buf, n->tip_name);
		strbuf_strip_suffix(buf, "^0");
		strbuf_addf(buf, "~%d", n->generation);
		return buf->buf;
	}
}

static void show_name(const struct object *obj,
		      const char *caller_name,
		      int always, int allow_undefined, int name_only)
{
	const char *name;
	const struct object_id *oid = &obj->oid;
	struct strbuf buf = STRBUF_INIT;

	if (!name_only)
		printf("%s ", caller_name ? caller_name : oid_to_hex(oid));
	name = get_rev_name(obj, &buf);
	if (name)
		printf("%s\n", name);
	else if (allow_undefined)
		printf("undefined\n");
	else if (always)
		printf("%s\n", find_unique_abbrev(oid, DEFAULT_ABBREV));
	else
		die("cannot describe '%s'", oid_to_hex(oid));
	strbuf_release(&buf);
}

static char const * const name_rev_usage[] = {
	N_("git name-rev [<options>] <commit>..."),
	N_("git name-rev [<options>] --all"),
	N_("git name-rev [<options>] --stdin"),
	NULL
};

static void name_rev_line(char *p, struct name_ref_data *data)
{
	struct strbuf buf = STRBUF_INIT;
	int counter = 0;
	char *p_start;
	const unsigned hexsz = the_hash_algo->hexsz;

	for (p_start = p; *p; p++) {
#define ishex(x) (isdigit((x)) || ((x) >= 'a' && (x) <= 'f'))
		if (!ishex(*p))
			counter = 0;
		else if (++counter == hexsz &&
			 !ishex(*(p+1))) {
			struct object_id oid;
			const char *name = NULL;
			char c = *(p+1);
			int p_len = p - p_start + 1;

			counter = 0;

			*(p+1) = 0;
			if (!get_oid(p - (hexsz - 1), &oid)) {
				struct object *o =
					lookup_object(the_repository, &oid);
				if (o)
					name = get_rev_name(o, &buf);
			}
			*(p+1) = c;

			if (!name)
				continue;

			if (data->name_only)
				printf("%.*s%s", p_len - hexsz, p_start, name);
			else
				printf("%.*s (%s)", p_len, p_start, name);
			p_start = p + 1;
		}
	}

	/* flush */
	if (p_start != p)
		fwrite(p_start, p - p_start, 1, stdout);

	strbuf_release(&buf);
}

int cmd_name_rev(int argc, const char **argv, const char *prefix)
{
	struct object_array revs = OBJECT_ARRAY_INIT;
	int all = 0, transform_stdin = 0, allow_undefined = 1, always = 0, peel_tag = 0;
	struct name_ref_data data = { 0, 0, STRING_LIST_INIT_NODUP, STRING_LIST_INIT_NODUP };
	struct option opts[] = {
		OPT_BOOL(0, "name-only", &data.name_only, N_("print only ref-based names (no object names)")),
		OPT_BOOL(0, "tags", &data.tags_only, N_("only use tags to name the commits")),
		OPT_STRING_LIST(0, "refs", &data.ref_filters, N_("pattern"),
				   N_("only use refs matching <pattern>")),
		OPT_STRING_LIST(0, "exclude", &data.exclude_filters, N_("pattern"),
				   N_("ignore refs matching <pattern>")),
		OPT_GROUP(""),
		OPT_BOOL(0, "all", &all, N_("list all commits reachable from all refs")),
		OPT_BOOL(0, "stdin", &transform_stdin, N_("read from stdin")),
		OPT_BOOL(0, "undefined", &allow_undefined, N_("allow to print `undefined` names (default)")),
		OPT_BOOL(0, "always",     &always,
			   N_("show abbreviated commit object as fallback")),
		{
			/* A Hidden OPT_BOOL */
			OPTION_SET_INT, 0, "peel-tag", &peel_tag, NULL,
			N_("dereference tags in the input (internal use)"),
			PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1,
		},
		OPT_END(),
	};

	init_commit_rev_name(&rev_names);
	git_config(git_default_config, NULL);
	argc = parse_options(argc, argv, prefix, opts, name_rev_usage, 0);
	if (all + transform_stdin + !!argc > 1) {
		error("Specify either a list, or --all, not both!");
		usage_with_options(name_rev_usage, opts);
	}
	if (all || transform_stdin)
		cutoff = 0;

	for (; argc; argc--, argv++) {
		struct object_id oid;
		struct object *object;
		struct commit *commit;

		if (get_oid(*argv, &oid)) {
			fprintf(stderr, "Could not get sha1 for %s. Skipping.\n",
					*argv);
			continue;
		}

		commit = NULL;
		object = parse_object(the_repository, &oid);
		if (object) {
			struct object *peeled = deref_tag(the_repository,
							  object, *argv, 0);
			if (peeled && peeled->type == OBJ_COMMIT)
				commit = (struct commit *)peeled;
		}

		if (!object) {
			fprintf(stderr, "Could not get object for %s. Skipping.\n",
					*argv);
			continue;
		}

		if (commit) {
			if (cutoff > commit->date)
				cutoff = commit->date;
		}

		if (peel_tag) {
			if (!commit) {
				fprintf(stderr, "Could not get commit for %s. Skipping.\n",
					*argv);
				continue;
			}
			object = (struct object *)commit;
		}
		add_object_array(object, *argv, &revs);
	}

	if (cutoff) {
		/* check for undeflow */
		if (cutoff > TIME_MIN + CUTOFF_DATE_SLOP)
			cutoff = cutoff - CUTOFF_DATE_SLOP;
		else
			cutoff = TIME_MIN;
	}
	for_each_ref(name_ref, &data);
	name_tips();

	if (transform_stdin) {
		char buffer[2048];

		while (!feof(stdin)) {
			char *p = fgets(buffer, sizeof(buffer), stdin);
			if (!p)
				break;
			name_rev_line(p, &data);
		}
	} else if (all) {
		int i, max;

		max = get_max_object_index();
		for (i = 0; i < max; i++) {
			struct object *obj = get_indexed_object(i);
			if (!obj || obj->type != OBJ_COMMIT)
				continue;
			show_name(obj, NULL,
				  always, allow_undefined, data.name_only);
		}
	} else {
		int i;
		for (i = 0; i < revs.nr; i++)
			show_name(revs.objects[i].item, revs.objects[i].name,
				  always, allow_undefined, data.name_only);
	}

	UNLEAK(revs);
	return 0;
}