summaryrefslogtreecommitdiff
path: root/show-branch.c
blob: 5778a594f44bd5fe06cd4b69eb37b3007a551385 (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
#include <stdlib.h>
#include "cache.h"
#include "commit.h"
#include "refs.h"

static const char show_branch_usage[] =
"git-show-branch [--all] [--heads] [--tags] [--more=count | --list | --independent | --merge-base ] [<refs>...]";

#define UNINTERESTING	01

#define REV_SHIFT	 2
#define MAX_REVS	29 /* should not exceed bits_per_int - REV_SHIFT */

static struct commit *interesting(struct commit_list *list)
{
	while (list) {
		struct commit *commit = list->item;
		list = list->next;
		if (commit->object.flags & UNINTERESTING)
			continue;
		return commit;
	}
	return NULL;
}

static struct commit *pop_one_commit(struct commit_list **list_p)
{
	struct commit *commit;
	struct commit_list *list;
	list = *list_p;
	commit = list->item;
	*list_p = list->next;
	free(list);
	return commit;
}

struct commit_name {
	const char *head_name; /* which head's ancestor? */
	int generation; /* how many parents away from head_name */
};

/* Name the commit as nth generation ancestor of head_name;
 * we count only the first-parent relationship for naming purposes.
 */
static void name_commit(struct commit *commit, const char *head_name, int nth)
{
	struct commit_name *name;
	if (!commit->object.util)
		commit->object.util = xmalloc(sizeof(struct commit_name));
	name = commit->object.util;
	name->head_name = head_name;
	name->generation = nth;
}

/* Parent is the first parent of the commit.  We may name it
 * as (n+1)th generation ancestor of the same head_name as
 * commit is nth generation ancestore of, if that generation
 * number is better than the name it already has.
 */
static void name_parent(struct commit *commit, struct commit *parent)
{
	struct commit_name *commit_name = commit->object.util;
	struct commit_name *parent_name = parent->object.util;
	if (!commit_name)
		return;
	if (!parent_name ||
	    commit_name->generation + 1 < parent_name->generation)
		name_commit(parent, commit_name->head_name,
			    commit_name->generation + 1);
}

static int name_first_parent_chain(struct commit *c)
{
	int i = 0;
	while (c) {
		struct commit *p;
		if (!c->object.util)
			break;
		if (!c->parents)
			break;
		p = c->parents->item;
		if (!p->object.util) {
			name_parent(c, p);
			i++;
		}
		c = p;
	}
	return i;
}

static void name_commits(struct commit_list *list,
			 struct commit **rev,
			 char **ref_name,
			 int num_rev)
{
	struct commit_list *cl;
	struct commit *c;
	int i;

	/* First give names to the given heads */
	for (cl = list; cl; cl = cl->next) {
		c = cl->item;
		if (c->object.util)
			continue;
		for (i = 0; i < num_rev; i++) {
			if (rev[i] == c) {
				name_commit(c, ref_name[i], 0);
				break;
			}
		}
	}

	/* Then commits on the first parent ancestry chain */
	do {
		i = 0;
		for (cl = list; cl; cl = cl->next) {
			i += name_first_parent_chain(cl->item);
		}
	} while (i);

	/* Finally, any unnamed commits */
	do {
		i = 0;
		for (cl = list; cl; cl = cl->next) {
			struct commit_list *parents;
			struct commit_name *n;
			int nth;
			c = cl->item;
			if (!c->object.util)
				continue;
			n = c->object.util;
			parents = c->parents;
			nth = 0;
			while (parents) {
				struct commit *p = parents->item;
				char newname[1000];
				parents = parents->next;
				nth++;
				if (p->object.util)
					continue;
				switch (n->generation) {
				case 0:
					sprintf(newname, "%s^%d",
						n->head_name, nth);
					break;
				case 1:
					sprintf(newname, "%s^^%d",
						n->head_name, nth);
					break;
				default:
					sprintf(newname, "%s~%d^%d",
						n->head_name, n->generation,
						nth);
				}
				name_commit(p, strdup(newname), 0);
				i++;
				name_first_parent_chain(p);
			}
		}
	} while (i);
}

static int mark_seen(struct commit *commit, struct commit_list **seen_p)
{
	if (!commit->object.flags) {
		insert_by_date(commit, seen_p);
		return 1;
	}
	return 0;
}

static void join_revs(struct commit_list **list_p,
		      struct commit_list **seen_p,
		      int num_rev, int extra)
{
	int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
	int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);

	while (*list_p) {
		struct commit_list *parents;
		struct commit *commit = pop_one_commit(list_p);
		int flags = commit->object.flags & all_mask;
		int still_interesting = !!interesting(*list_p);

		if (!still_interesting && extra < 0)
			break;

		mark_seen(commit, seen_p);
		if ((flags & all_revs) == all_revs)
			flags |= UNINTERESTING;
		parents = commit->parents;

		while (parents) {
			struct commit *p = parents->item;
			int this_flag = p->object.flags;
			parents = parents->next;
			if ((this_flag & flags) == flags)
				continue;
			parse_commit(p);
			if (mark_seen(p, seen_p) && !still_interesting)
				extra--;
			p->object.flags |= flags;
			insert_by_date(p, list_p);
		}
	}
}

static void show_one_commit(struct commit *commit)
{
	char pretty[128], *cp;
	struct commit_name *name = commit->object.util;
	if (commit->object.parsed)
		pretty_print_commit(CMIT_FMT_ONELINE, commit->buffer, ~0,
				    pretty, sizeof(pretty));
	else
		strcpy(pretty, "(unavailable)");
	if (!strncmp(pretty, "[PATCH] ", 8))
		cp = pretty + 8;
	else
		cp = pretty;
	if (name && name->head_name) {
		printf("[%s", name->head_name);
		if (name->generation)
			printf("~%d", name->generation);
		printf("] ");
	}
	puts(cp);
}

static char *ref_name[MAX_REVS + 1];
static int ref_name_cnt;

static int compare_ref_name(const void *a_, const void *b_)
{
	const char * const*a = a_, * const*b = b_;
	return strcmp(*a, *b);
}

static void sort_ref_range(int bottom, int top)
{
	qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
	      compare_ref_name);
}

static int append_ref(const char *refname, const unsigned char *sha1)
{
	struct commit *commit = lookup_commit_reference_gently(sha1, 1);
	if (!commit)
		return 0;
	if (MAX_REVS < ref_name_cnt) {
		fprintf(stderr, "warning: ignoring %s; "
			"cannot handle more than %d refs",
			refname, MAX_REVS);
		return 0;
	}
	ref_name[ref_name_cnt++] = strdup(refname);
	ref_name[ref_name_cnt] = NULL;
	return 0;
}

static int append_head_ref(const char *refname, const unsigned char *sha1)
{
	if (strncmp(refname, "refs/heads/", 11))
		return 0;
	return append_ref(refname + 11, sha1);
}

static int append_tag_ref(const char *refname, const unsigned char *sha1)
{
	if (strncmp(refname, "refs/tags/", 10))
		return 0;
	return append_ref(refname + 5, sha1);
}

static void snarf_refs(int head, int tag)
{
	if (head) {
		int orig_cnt = ref_name_cnt;
		for_each_ref(append_head_ref);
		sort_ref_range(orig_cnt, ref_name_cnt);
	}
	if (tag) {
		int orig_cnt = ref_name_cnt;
		for_each_ref(append_tag_ref);
		sort_ref_range(orig_cnt, ref_name_cnt);
	}
}

static int rev_is_head(char *head_path, int headlen,
		       char *name,
		       unsigned char *head_sha1, unsigned char *sha1)
{
	int namelen;
	if ((!head_path[0]) || memcmp(head_sha1, sha1, 20))
		return 0;
	namelen = strlen(name);
	if ((headlen < namelen) ||
	    memcmp(head_path + headlen - namelen, name, namelen))
		return 0;
	if (headlen == namelen ||
	    head_path[headlen - namelen - 1] == '/')
		return 1;
	return 0;
}

static int show_merge_base(struct commit_list *seen, int num_rev)
{
	int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
	int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
	int exit_status = 1;

	while (seen) {
		struct commit *commit = pop_one_commit(&seen);
		int flags = commit->object.flags & all_mask;
		if (!(flags & UNINTERESTING) &&
		    ((flags & all_revs) == all_revs)) {
			puts(sha1_to_hex(commit->object.sha1));
			exit_status = 0;
			commit->object.flags |= UNINTERESTING;
		}
	}
	return exit_status;
}

static int show_independent(struct commit **rev,
			    int num_rev,
			    char **ref_name,
			    unsigned int *rev_mask)
{
	int i;

	for (i = 0; i < num_rev; i++) {
		struct commit *commit = rev[i];
		unsigned int flag = rev_mask[i];

		if (commit->object.flags == flag)
			puts(sha1_to_hex(commit->object.sha1));
		commit->object.flags |= UNINTERESTING;
	}
	return 0;
}

int main(int ac, char **av)
{
	struct commit *rev[MAX_REVS], *commit;
	struct commit_list *list = NULL, *seen = NULL;
	unsigned int rev_mask[MAX_REVS];
	int num_rev, i, extra = 0;
	int all_heads = 0, all_tags = 0;
	int all_mask, all_revs, shown_merge_point;
	char head_path[128];
	int head_path_len;
	unsigned char head_sha1[20];
	int merge_base = 0;
	int independent = 0;
	char **label;

	setup_git_directory();

	while (1 < ac && av[1][0] == '-') {
		char *arg = av[1];
		if (!strcmp(arg, "--all"))
			all_heads = all_tags = 1;
		else if (!strcmp(arg, "--heads"))
			all_heads = 1;
		else if (!strcmp(arg, "--tags"))
			all_tags = 1;
		else if (!strcmp(arg, "--more"))
			extra = 1;
		else if (!strcmp(arg, "--list"))
			extra = -1;
		else if (!strncmp(arg, "--more=", 7))
			extra = atoi(arg + 7);
		else if (!strcmp(arg, "--merge-base"))
			merge_base = 1;
		else if (!strcmp(arg, "--independent"))
			independent = 1;
		else
			usage(show_branch_usage);
		ac--; av++;
	}
	ac--; av++;

	/* Only one of these is allowed */
	if (1 < independent + merge_base + (extra != 0))
		usage(show_branch_usage);

	if (all_heads + all_tags)
		snarf_refs(all_heads, all_tags);

	while (0 < ac) {
		unsigned char revkey[20];
		if (get_sha1(*av, revkey))
			die("bad sha1 reference %s", *av);
		append_ref(*av, revkey);
		ac--; av++;
	}

	/* If still no revs, then add heads */
	if (!ref_name_cnt)
		snarf_refs(1, 0);

	for (num_rev = 0; ref_name[num_rev]; num_rev++) {
		unsigned char revkey[20];
		unsigned int flag = 1u << (num_rev + REV_SHIFT);

		if (MAX_REVS <= num_rev)
			die("cannot handle more than %d revs.", MAX_REVS);
		if (get_sha1(ref_name[num_rev], revkey))
			usage(show_branch_usage);
		commit = lookup_commit_reference(revkey);
		if (!commit)
			die("cannot find commit %s (%s)",
			    ref_name[num_rev], revkey);
		parse_commit(commit);
		mark_seen(commit, &seen);

		/* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
		 * and so on.  REV_SHIFT bits from bit 0 are used for
		 * internal bookkeeping.
		 */
		commit->object.flags |= flag;
		if (commit->object.flags == flag)
			insert_by_date(commit, &list);
		rev[num_rev] = commit;
	}
	for (i = 0; i < num_rev; i++)
		rev_mask[i] = rev[i]->object.flags;

	if (0 <= extra)
		join_revs(&list, &seen, num_rev, extra);

	head_path_len = readlink(".git/HEAD", head_path, sizeof(head_path)-1);
	if ((head_path_len < 0) || get_sha1("HEAD", head_sha1))
		head_path[0] = 0;
	else
		head_path[head_path_len] = 0;

	if (merge_base)
		return show_merge_base(seen, num_rev);

	if (independent)
		return show_independent(rev, num_rev, ref_name, rev_mask);

	/* Show list; --more=-1 means list-only */
	if (1 < num_rev || extra < 0) {
		for (i = 0; i < num_rev; i++) {
			int j;
			int is_head = rev_is_head(head_path,
						  head_path_len,
						  ref_name[i],
						  head_sha1,
						  rev[i]->object.sha1);
			if (extra < 0)
				printf("%c [%s] ",
				       is_head ? '*' : ' ', ref_name[i]);
			else {
				for (j = 0; j < i; j++)
					putchar(' ');
				printf("%c [%s] ",
				       is_head ? '*' : '!', ref_name[i]);
			}
			show_one_commit(rev[i]);
		}
		if (0 <= extra) {
			for (i = 0; i < num_rev; i++)
				putchar('-');
			putchar('\n');
		}
	}
	if (extra < 0)
		exit(0);

	/* Sort topologically */
	sort_in_topological_order(&seen);

	/* Give names to commits */
	name_commits(seen, rev, ref_name, num_rev);

	all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
	all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
	shown_merge_point = 0;

	while (seen) {
		struct commit *commit = pop_one_commit(&seen);
		int this_flag = commit->object.flags;
		int is_merge_point = (this_flag & all_revs) == all_revs;
		static char *obvious[] = { "" };

		if (is_merge_point)
			shown_merge_point = 1;

		if (1 < num_rev) {
			for (i = 0; i < num_rev; i++)
				putchar((this_flag & (1u << (i + REV_SHIFT)))
					? '+' : ' ');
			putchar(' ');
		}
		show_one_commit(commit);
		if (num_rev == 1)
			label = obvious;
		if (shown_merge_point && is_merge_point)
			if (--extra < 0)
				break;
	}
	return 0;
}