summaryrefslogtreecommitdiff
path: root/fetch-pack.c
blob: e8708aa802b8e09d8044bb99dbccb0fecdb14481 (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
#include "cache.h"
#include "refs.h"
#include "pkt-line.h"
#include "commit.h"
#include "tag.h"

static int keep_pack;
static int quiet;
static int verbose;
static int fetch_all;
static const char fetch_pack_usage[] =
"git-fetch-pack [--all] [-q] [-v] [-k] [--thin] [--exec=upload-pack] [host:]directory <refs>...";
static const char *exec = "git-upload-pack";

#define COMPLETE	(1U << 0)
#define COMMON		(1U << 1)
#define COMMON_REF	(1U << 2)
#define SEEN		(1U << 3)
#define POPPED		(1U << 4)

/*
 * After sending this many "have"s if we do not get any new ACK , we
 * give up traversing our history.
 */
#define MAX_IN_VAIN 256

static struct commit_list *rev_list;
static int non_common_revs, multi_ack, use_thin_pack, use_sideband;

static void rev_list_push(struct commit *commit, int mark)
{
	if (!(commit->object.flags & mark)) {
		commit->object.flags |= mark;

		if (!(commit->object.parsed))
			parse_commit(commit);

		insert_by_date(commit, &rev_list);

		if (!(commit->object.flags & COMMON))
			non_common_revs++;
	}
}

static int rev_list_insert_ref(const char *path, const unsigned char *sha1)
{
	struct object *o = deref_tag(parse_object(sha1), path, 0);

	if (o && o->type == OBJ_COMMIT)
		rev_list_push((struct commit *)o, SEEN);

	return 0;
}

/*
   This function marks a rev and its ancestors as common.
   In some cases, it is desirable to mark only the ancestors (for example
   when only the server does not yet know that they are common).
*/

static void mark_common(struct commit *commit,
		int ancestors_only, int dont_parse)
{
	if (commit != NULL && !(commit->object.flags & COMMON)) {
		struct object *o = (struct object *)commit;

		if (!ancestors_only)
			o->flags |= COMMON;

		if (!(o->flags & SEEN))
			rev_list_push(commit, SEEN);
		else {
			struct commit_list *parents;

			if (!ancestors_only && !(o->flags & POPPED))
				non_common_revs--;
			if (!o->parsed && !dont_parse)
				parse_commit(commit);

			for (parents = commit->parents;
					parents;
					parents = parents->next)
				mark_common(parents->item, 0, dont_parse);
		}
	}
}

/*
  Get the next rev to send, ignoring the common.
*/

static const unsigned char* get_rev(void)
{
	struct commit *commit = NULL;

	while (commit == NULL) {
		unsigned int mark;
		struct commit_list* parents;

		if (rev_list == NULL || non_common_revs == 0)
			return NULL;

		commit = rev_list->item;
		if (!(commit->object.parsed))
			parse_commit(commit);
		commit->object.flags |= POPPED;
		if (!(commit->object.flags & COMMON))
			non_common_revs--;
	
		parents = commit->parents;

		if (commit->object.flags & COMMON) {
			/* do not send "have", and ignore ancestors */
			commit = NULL;
			mark = COMMON | SEEN;
		} else if (commit->object.flags & COMMON_REF)
			/* send "have", and ignore ancestors */
			mark = COMMON | SEEN;
		else
			/* send "have", also for its ancestors */
			mark = SEEN;

		while (parents) {
			if (!(parents->item->object.flags & SEEN))
				rev_list_push(parents->item, mark);
			if (mark & COMMON)
				mark_common(parents->item, 1, 0);
			parents = parents->next;
		}

		rev_list = rev_list->next;
	}

	return commit->object.sha1;
}

static int find_common(int fd[2], unsigned char *result_sha1,
		       struct ref *refs)
{
	int fetching;
	int count = 0, flushes = 0, retval;
	const unsigned char *sha1;
	unsigned in_vain = 0;
	int got_continue = 0;

	for_each_ref(rev_list_insert_ref);

	fetching = 0;
	for ( ; refs ; refs = refs->next) {
		unsigned char *remote = refs->old_sha1;
		struct object *o;

		/*
		 * If that object is complete (i.e. it is an ancestor of a
		 * local ref), we tell them we have it but do not have to
		 * tell them about its ancestors, which they already know
		 * about.
		 *
		 * We use lookup_object here because we are only
		 * interested in the case we *know* the object is
		 * reachable and we have already scanned it.
		 */
		if (((o = lookup_object(remote)) != NULL) &&
				(o->flags & COMPLETE)) {
			continue;
		}

		if (!fetching)
			packet_write(fd[1], "want %s%s%s%s%s\n",
				     sha1_to_hex(remote),
				     (multi_ack ? " multi_ack" : ""),
				     (use_sideband == 2 ? " side-band-64k" : ""),
				     (use_sideband == 1 ? " side-band" : ""),
				     (use_thin_pack ? " thin-pack" : ""));
		else
			packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
		fetching++;
	}
	packet_flush(fd[1]);
	if (!fetching)
		return 1;

	flushes = 0;
	retval = -1;
	while ((sha1 = get_rev())) {
		packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
		if (verbose)
			fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
		in_vain++;
		if (!(31 & ++count)) {
			int ack;

			packet_flush(fd[1]);
			flushes++;

			/*
			 * We keep one window "ahead" of the other side, and
			 * will wait for an ACK only on the next one
			 */
			if (count == 32)
				continue;

			do {
				ack = get_ack(fd[0], result_sha1);
				if (verbose && ack)
					fprintf(stderr, "got ack %d %s\n", ack,
							sha1_to_hex(result_sha1));
				if (ack == 1) {
					flushes = 0;
					multi_ack = 0;
					retval = 0;
					goto done;
				} else if (ack == 2) {
					struct commit *commit =
						lookup_commit(result_sha1);
					mark_common(commit, 0, 1);
					retval = 0;
					in_vain = 0;
					got_continue = 1;
				}
			} while (ack);
			flushes--;
			if (got_continue && MAX_IN_VAIN < in_vain) {
				if (verbose)
					fprintf(stderr, "giving up\n");
				break; /* give up */
			}
		}
	}
done:
	packet_write(fd[1], "done\n");
	if (verbose)
		fprintf(stderr, "done\n");
	if (retval != 0) {
		multi_ack = 0;
		flushes++;
	}
	while (flushes || multi_ack) {
		int ack = get_ack(fd[0], result_sha1);
		if (ack) {
			if (verbose)
				fprintf(stderr, "got ack (%d) %s\n", ack,
					sha1_to_hex(result_sha1));
			if (ack == 1)
				return 0;
			multi_ack = 1;
			continue;
		}
		flushes--;
	}
	return retval;
}

static struct commit_list *complete;

static int mark_complete(const char *path, const unsigned char *sha1)
{
	struct object *o = parse_object(sha1);

	while (o && o->type == OBJ_TAG) {
		struct tag *t = (struct tag *) o;
		if (!t->tagged)
			break; /* broken repository */
		o->flags |= COMPLETE;
		o = parse_object(t->tagged->sha1);
	}
	if (o && o->type == OBJ_COMMIT) {
		struct commit *commit = (struct commit *)o;
		commit->object.flags |= COMPLETE;
		insert_by_date(commit, &complete);
	}
	return 0;
}

static void mark_recent_complete_commits(unsigned long cutoff)
{
	while (complete && cutoff <= complete->item->date) {
		if (verbose)
			fprintf(stderr, "Marking %s as complete\n",
				sha1_to_hex(complete->item->object.sha1));
		pop_most_recent_commit(&complete, COMPLETE);
	}
}

static void filter_refs(struct ref **refs, int nr_match, char **match)
{
	struct ref **return_refs;
	struct ref *newlist = NULL;
	struct ref **newtail = &newlist;
	struct ref *ref, *next;
	struct ref *fastarray[32];

	if (nr_match && !fetch_all) {
		if (ARRAY_SIZE(fastarray) < nr_match)
			return_refs = xcalloc(nr_match, sizeof(struct ref *));
		else {
			return_refs = fastarray;
			memset(return_refs, 0, sizeof(struct ref *) * nr_match);
		}
	}
	else
		return_refs = NULL;

	for (ref = *refs; ref; ref = next) {
		next = ref->next;
		if (!memcmp(ref->name, "refs/", 5) &&
		    check_ref_format(ref->name + 5))
			; /* trash */
		else if (fetch_all) {
			*newtail = ref;
			ref->next = NULL;
			newtail = &ref->next;
			continue;
		}
		else {
			int order = path_match(ref->name, nr_match, match);
			if (order) {
				return_refs[order-1] = ref;
				continue; /* we will link it later */
			}
		}
		free(ref);
	}

	if (!fetch_all) {
		int i;
		for (i = 0; i < nr_match; i++) {
			ref = return_refs[i];
			if (ref) {
				*newtail = ref;
				ref->next = NULL;
				newtail = &ref->next;
			}
		}
		if (return_refs != fastarray)
			free(return_refs);
	}
	*refs = newlist;
}

static int everything_local(struct ref **refs, int nr_match, char **match)
{
	struct ref *ref;
	int retval;
	unsigned long cutoff = 0;

	track_object_refs = 0;
	save_commit_buffer = 0;

	for (ref = *refs; ref; ref = ref->next) {
		struct object *o;

		o = parse_object(ref->old_sha1);
		if (!o)
			continue;

		/* We already have it -- which may mean that we were
		 * in sync with the other side at some time after
		 * that (it is OK if we guess wrong here).
		 */
		if (o->type == OBJ_COMMIT) {
			struct commit *commit = (struct commit *)o;
			if (!cutoff || cutoff < commit->date)
				cutoff = commit->date;
		}
	}

	for_each_ref(mark_complete);
	if (cutoff)
		mark_recent_complete_commits(cutoff);

	/*
	 * Mark all complete remote refs as common refs.
	 * Don't mark them common yet; the server has to be told so first.
	 */
	for (ref = *refs; ref; ref = ref->next) {
		struct object *o = deref_tag(lookup_object(ref->old_sha1),
					     NULL, 0);

		if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
			continue;

		if (!(o->flags & SEEN)) {
			rev_list_push((struct commit *)o, COMMON_REF | SEEN);

			mark_common((struct commit *)o, 1, 1);
		}
	}

	filter_refs(refs, nr_match, match);

	for (retval = 1, ref = *refs; ref ; ref = ref->next) {
		const unsigned char *remote = ref->old_sha1;
		unsigned char local[20];
		struct object *o;

		o = lookup_object(remote);
		if (!o || !(o->flags & COMPLETE)) {
			retval = 0;
			if (!verbose)
				continue;
			fprintf(stderr,
				"want %s (%s)\n", sha1_to_hex(remote),
				ref->name);
			continue;
		}

		hashcpy(ref->new_sha1, local);
		if (!verbose)
			continue;
		fprintf(stderr,
			"already have %s (%s)\n", sha1_to_hex(remote),
			ref->name);
	}
	return retval;
}

static int fetch_pack(int fd[2], int nr_match, char **match)
{
	struct ref *ref;
	unsigned char sha1[20];
	int status;

	get_remote_heads(fd[0], &ref, 0, NULL, 0);
	if (server_supports("multi_ack")) {
		if (verbose)
			fprintf(stderr, "Server supports multi_ack\n");
		multi_ack = 1;
	}
	if (server_supports("side-band-64k")) {
		if (verbose)
			fprintf(stderr, "Server supports side-band-64k\n");
		use_sideband = 2;
	}
	else if (server_supports("side-band")) {
		if (verbose)
			fprintf(stderr, "Server supports side-band\n");
		use_sideband = 1;
	}
	if (!ref) {
		packet_flush(fd[1]);
		die("no matching remote head");
	}
	if (everything_local(&ref, nr_match, match)) {
		packet_flush(fd[1]);
		goto all_done;
	}
	if (find_common(fd, sha1, ref) < 0)
		if (!keep_pack)
			/* When cloning, it is not unusual to have
			 * no common commit.
			 */
			fprintf(stderr, "warning: no common commits\n");

	if (keep_pack)
		status = receive_keep_pack(fd, "git-fetch-pack", quiet, use_sideband);
	else
		status = receive_unpack_pack(fd, "git-fetch-pack", quiet, use_sideband);

	if (status)
		die("git-fetch-pack: fetch failed.");

 all_done:
	while (ref) {
		printf("%s %s\n",
		       sha1_to_hex(ref->old_sha1), ref->name);
		ref = ref->next;
	}
	return 0;
}

int main(int argc, char **argv)
{
	int i, ret, nr_heads;
	char *dest = NULL, **heads;
	int fd[2];
	pid_t pid;

	setup_git_directory();

	nr_heads = 0;
	heads = NULL;
	for (i = 1; i < argc; i++) {
		char *arg = argv[i];

		if (*arg == '-') {
			if (!strncmp("--exec=", arg, 7)) {
				exec = arg + 7;
				continue;
			}
			if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
				quiet = 1;
				continue;
			}
			if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
				keep_pack = 1;
				continue;
			}
			if (!strcmp("--thin", arg)) {
				use_thin_pack = 1;
				continue;
			}
			if (!strcmp("--all", arg)) {
				fetch_all = 1;
				continue;
			}
			if (!strcmp("-v", arg)) {
				verbose = 1;
				continue;
			}
			usage(fetch_pack_usage);
		}
		dest = arg;
		heads = argv + i + 1;
		nr_heads = argc - i - 1;
		break;
	}
	if (!dest)
		usage(fetch_pack_usage);
	if (keep_pack)
		use_thin_pack = 0;
	pid = git_connect(fd, dest, exec);
	if (pid < 0)
		return 1;
	ret = fetch_pack(fd, nr_heads, heads);
	close(fd[0]);
	close(fd[1]);
	ret |= finish_connect(pid);

	if (!ret && nr_heads) {
		/* If the heads to pull were given, we should have
		 * consumed all of them by matching the remote.
		 * Otherwise, 'git-fetch remote no-such-ref' would
		 * silently succeed without issuing an error.
		 */
		for (i = 0; i < nr_heads; i++)
			if (heads[i] && heads[i][0]) {
				error("no such remote ref %s", heads[i]);
				ret = 1;
			}
	}

	return !!ret;
}