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Date:: Fri Jan 7 23:32:27 2022 UTC
Message:: map raw object files into memory while packing if possible
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1 /*
2  * Copyright (c) 2020 Ori Bernstein
3  * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/types.h>
19 #include <sys/queue.h>
20 #include <sys/tree.h>
21 #include <sys/uio.h>
22 #include <sys/stat.h>
23 #include <sys/time.h>
24 
25 #include <stdint.h>
26 #include <imsg.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <sha1.h>
31 #include <time.h>
32 #include <limits.h>
33 #include <zlib.h>
34 
35 #include "got_error.h"
36 #include "got_cancel.h"
37 #include "got_object.h"
38 #include "got_path.h"
39 #include "got_reference.h"
40 #include "got_repository_admin.h"
41 #include "got_opentemp.h"
42 
43 #include "got_lib_deltify.h"
44 #include "got_lib_delta.h"
45 #include "got_lib_object.h"
46 #include "got_lib_object_idset.h"
47 #include "got_lib_object_cache.h"
48 #include "got_lib_deflate.h"
49 #include "got_lib_pack.h"
50 #include "got_lib_privsep.h"
51 #include "got_lib_repository.h"
52 #include "got_lib_ratelimit.h"
53 
54 #ifndef MIN
55 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
56 #endif
57 
58 #ifndef MAX
59 #define	MAX(_a,_b) ((_a) > (_b) ? (_a) : (_b))
60 #endif
61 
62 struct got_pack_meta {
63 	struct got_object_id id;
64 	char	*path;
65 	int	obj_type;
66 	off_t	size;
67 	time_t	mtime;
68 
69 	/* The best delta we picked */
70 	struct got_pack_meta *head;
71 	struct got_pack_meta *prev;
72 	off_t	delta_offset;	/* offset in delta cache file */
73 	off_t	delta_len;	/* length in delta cache file */
74 	int	nchain;
75 
76 	/* Only used for delta window */
77 	struct got_delta_table *dtab;
78 
79 	/* Only used for writing offset deltas */
80 	off_t	off;
81 };
82 
83 struct got_pack_metavec {
84 	struct got_pack_meta **meta;
85 	int nmeta;
86 	int metasz;
87 };
88 
89 static const struct got_error *
90 alloc_meta(struct got_pack_meta **new, struct got_object_id *id,
91     const char *path, int obj_type, time_t mtime)
92 {
93 	const struct got_error *err = NULL;
94 	struct got_pack_meta *m;
95 
96 	*new = NULL;
97 
98 	m = calloc(1, sizeof(*m));
99 	if (m == NULL)
100 		return got_error_from_errno("calloc");
101 
102 	memcpy(&m->id, id, sizeof(m->id));
103 
104 	m->path = strdup(path);
105 	if (m->path == NULL) {
106 		err = got_error_from_errno("strdup");
107 		free(m);
108 		return err;
109 	}
110 
111 	m->obj_type = obj_type;
112 	m->mtime = mtime;
113 	*new = m;
114 	return NULL;
115 }
116 
117 static void
118 clear_meta(struct got_pack_meta *meta)
119 {
120 	if (meta == NULL)
121 		return;
122 	free(meta->path);
123 	meta->path = NULL;
124 }
125 
126 static void
127 free_nmeta(struct got_pack_meta **meta, int nmeta)
128 {
129 	int i;
130 
131 	for (i = 0; i < nmeta; i++)
132 		clear_meta(meta[i]);
133 	free(meta);
134 }
135 
136 static int
137 delta_order_cmp(const void *pa, const void *pb)
138 {
139 	struct got_pack_meta *a, *b;
140 	int cmp;
141 
142 	a = *(struct got_pack_meta **)pa;
143 	b = *(struct got_pack_meta **)pb;
144 
145 	if (a->obj_type != b->obj_type)
146 		return a->obj_type - b->obj_type;
147 	cmp = strcmp(a->path, b->path);
148 	if (cmp != 0)
149 		return cmp;
150 	if (a->mtime != b->mtime)
151 		return a->mtime - b->mtime;
152 	return got_object_id_cmp(&a->id, &b->id);
153 }
154 
155 static int
156 delta_size(struct got_delta_instruction *deltas, int ndeltas)
157 {
158 	int i, size = 32;
159 	for (i = 0; i < ndeltas; i++) {
160 		if (deltas[i].copy)
161 			size += GOT_DELTA_SIZE_SHIFT;
162 		else
163 			size += deltas[i].len + 1;
164 	}
165 	return size;
166 }
167 
168 static const struct got_error *
169 encode_delta(struct got_pack_meta *m, struct got_raw_object *o,
170     struct got_delta_instruction *deltas, int ndeltas,
171     off_t base_size, FILE *f)
172 {
173 	unsigned char buf[16], *bp;
174 	int i, j;
175 	off_t n;
176 	size_t w;
177 	struct got_delta_instruction *d;
178 
179 	/* base object size */
180 	buf[0] = base_size & GOT_DELTA_SIZE_VAL_MASK;
181 	n = base_size >> GOT_DELTA_SIZE_SHIFT;
182 	for (i = 1; n > 0; i++) {
183 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
184 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
185 		n >>= GOT_DELTA_SIZE_SHIFT;
186 	}
187 	w = fwrite(buf, 1, i, f);
188 	if (w != i)
189 		return got_ferror(f, GOT_ERR_IO);
190 
191 	/* target object size */
192 	buf[0] = o->size & GOT_DELTA_SIZE_VAL_MASK;
193 	n = o->size >> GOT_DELTA_SIZE_SHIFT;
194 	for (i = 1; n > 0; i++) {
195 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
196 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
197 		n >>= GOT_DELTA_SIZE_SHIFT;
198 	}
199 	w = fwrite(buf, 1, i, f);
200 	if (w != i)
201 		return got_ferror(f, GOT_ERR_IO);
202 
203 	for (j = 0; j < ndeltas; j++) {
204 		d = &deltas[j];
205 		if (d->copy) {
206 			n = d->offset;
207 			bp = &buf[1];
208 			buf[0] = GOT_DELTA_BASE_COPY;
209 			for (i = 0; i < 4; i++) {
210 				/* DELTA_COPY_OFF1 ... DELTA_COPY_OFF4 */
211 				buf[0] |= 1 << i;
212 				*bp++ = n & 0xff;
213 				n >>= 8;
214 				if (n == 0)
215 					break;
216 			}
217 
218 			n = d->len;
219 			if (n != GOT_DELTA_COPY_DEFAULT_LEN) {
220 				/* DELTA_COPY_LEN1 ... DELTA_COPY_LEN3 */
221 				for (i = 0; i < 3 && n > 0; i++) {
222 					buf[0] |= 1 << (i + 4);
223 					*bp++ = n & 0xff;
224 					n >>= 8;
225 				}
226 			}
227 			w = fwrite(buf, 1, bp - buf, f);
228 			if (w != bp - buf)
229 				return got_ferror(f, GOT_ERR_IO);
230 		} else if (o->f == NULL) {
231 			n = 0;
232 			while (n != d->len) {
233 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
234 				w = fwrite(buf, 1, 1, f);
235 				if (w != 1)
236 					return got_ferror(f, GOT_ERR_IO);
237 				w = fwrite(o->data + o->hdrlen + d->offset + n,
238 				    1, buf[0], f);
239 				if (w != buf[0])
240 					return got_ferror(f, GOT_ERR_IO);
241 				n += buf[0];
242 			}
243 		} else {
244 			char content[128];
245 			size_t r;
246 			if (fseeko(o->f, o->hdrlen + d->offset, SEEK_SET) == -1)
247 				return got_error_from_errno("fseeko");
248 			n = 0;
249 			while (n != d->len) {
250 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
251 				w = fwrite(buf, 1, 1, f);
252 				if (w != 1)
253 					return got_ferror(f, GOT_ERR_IO);
254 				r = fread(content, 1, buf[0], o->f);
255 				if (r != buf[0])
256 					return got_ferror(o->f, GOT_ERR_IO);
257 				w = fwrite(content, 1, buf[0], f);
258 				if (w != buf[0])
259 					return got_ferror(f, GOT_ERR_IO);
260 				n += buf[0];
261 			}
262 		}
263 	}
264 
265 	return NULL;
266 }
267 
268 static const struct got_error *
269 report_progress(got_pack_progress_cb progress_cb, void *progress_arg,
270     struct got_ratelimit *rl, off_t packfile_size, int ncommits,
271     int nobj_total, int obj_deltify, int nobj_written)
272 {
273 	const struct got_error *err;
274 	int elapsed;
275 
276 	if (progress_cb == NULL)
277 		return NULL;
278 
279 	err = got_ratelimit_check(&elapsed, rl);
280 	if (err || !elapsed)
281 		return err;
282 
283 	return progress_cb(progress_arg, packfile_size, ncommits,
284 	    nobj_total, obj_deltify, nobj_written);
285 }
286 
287 static const struct got_error *
288 pick_deltas(struct got_pack_meta **meta, int nmeta, int nours,
289     FILE *delta_cache, struct got_repository *repo,
290     got_pack_progress_cb progress_cb, void *progress_arg,
291     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
292 {
293 	const struct got_error *err = NULL;
294 	struct got_pack_meta *m = NULL, *base = NULL;
295 	struct got_raw_object *raw = NULL, *base_raw = NULL;
296 	struct got_delta_instruction *deltas = NULL, *best_deltas = NULL;
297 	int i, j, size, best_size, ndeltas, best_ndeltas;
298 	const int max_base_candidates = 3;
299 	int outfd = -1;
300 
301 	qsort(meta, nmeta, sizeof(struct got_pack_meta *), delta_order_cmp);
302 	for (i = 0; i < nmeta; i++) {
303 		if (cancel_cb) {
304 			err = (*cancel_cb)(cancel_arg);
305 			if (err)
306 				break;
307 		}
308 		err = report_progress(progress_cb, progress_arg, rl,
309 		    0L, nours, nmeta, i, 0);
310 		if (err)
311 			goto done;
312 		m = meta[i];
313 
314 		if (m->obj_type == GOT_OBJ_TYPE_COMMIT ||
315 		    m->obj_type == GOT_OBJ_TYPE_TAG)
316 			continue;
317 
318 		err = got_object_raw_open(&raw, &outfd, repo, &m->id);
319 		if (err)
320 			goto done;
321 		m->size = raw->size;
322 
323 		if (raw->f == NULL) {
324 			err = got_deltify_init_mem(&m->dtab, raw->data,
325 			    raw->hdrlen, raw->size + raw->hdrlen);
326 		} else {
327 			err = got_deltify_init(&m->dtab, raw->f, raw->hdrlen,
328 			    raw->size + raw->hdrlen);
329 		}
330 		if (err)
331 			goto done;
332 
333 		if (i > max_base_candidates) {
334 			struct got_pack_meta *n = NULL;
335 			n = meta[i - (max_base_candidates + 1)];
336 			got_deltify_free(n->dtab);
337 			n->dtab = NULL;
338 		}
339 
340 		best_size = raw->size;
341 		best_ndeltas = 0;
342 		for (j = MAX(0, i - max_base_candidates); j < i; j++) {
343 			if (cancel_cb) {
344 				err = (*cancel_cb)(cancel_arg);
345 				if (err)
346 					goto done;
347 			}
348 			base = meta[j];
349 			/* long chains make unpacking slow, avoid such bases */
350 			if (base->nchain >= 128 ||
351 			    base->obj_type != m->obj_type)
352 				continue;
353 
354 			err = got_object_raw_open(&base_raw, &outfd, repo,
355 			    &base->id);
356 			if (err)
357 				goto done;
358 			if (raw->f == NULL && base_raw->f == NULL) {
359 				err = got_deltify_mem_mem(&deltas, &ndeltas,
360 				    raw->data, raw->hdrlen,
361 				    raw->size + raw->hdrlen,
362 				    base->dtab, base_raw->data,
363 				    base_raw->hdrlen,
364 				    base_raw->size + base_raw->hdrlen);
365 			} else if (raw->f == NULL) {
366 				err = got_deltify_mem_file(&deltas, &ndeltas,
367 				    raw->data, raw->hdrlen,
368 				    raw->size + raw->hdrlen,
369 				    base->dtab, base_raw->f,
370 				    base_raw->hdrlen,
371 				    base_raw->size + base_raw->hdrlen);
372 			} else if (base_raw->f == NULL) {
373 				err = got_deltify_file_mem(&deltas, &ndeltas,
374 				    raw->f, raw->hdrlen,
375 				    raw->size + raw->hdrlen,
376 				    base->dtab, base_raw->data,
377 				    base_raw->hdrlen,
378 				    base_raw->size + base_raw->hdrlen);
379 			} else {
380 				err = got_deltify(&deltas, &ndeltas,
381 				    raw->f, raw->hdrlen,
382 				    raw->size + raw->hdrlen,
383 				    base->dtab, base_raw->f, base_raw->hdrlen,
384 				    base_raw->size + base_raw->hdrlen);
385 			}
386 			got_object_raw_close(base_raw);
387 			base_raw = NULL;
388 			if (err)
389 				goto done;
390 
391 			size = delta_size(deltas, ndeltas);
392 			if (size + 32 < best_size){
393 				/*
394 				 * if we already picked a best delta,
395 				 * replace it.
396 				 */
397 				best_size = size;
398 				free(best_deltas);
399 				best_deltas = deltas;
400 				best_ndeltas = ndeltas;
401 				deltas = NULL;
402 				m->nchain = base->nchain + 1;
403 				m->prev = base;
404 				m->head = base->head;
405 				if (m->head == NULL)
406 					m->head = base;
407 			} else {
408 				free(deltas);
409 				deltas = NULL;
410 				ndeltas = 0;
411 			}
412 		}
413 
414 		if (best_ndeltas > 0) {
415 			m->delta_offset = ftello(delta_cache);
416 			err = encode_delta(m, raw, best_deltas,
417 			    best_ndeltas, m->prev->size, delta_cache);
418 			free(best_deltas);
419 			best_deltas = NULL;
420 			best_ndeltas = 0;
421 			if (err)
422 				goto done;
423 			m->delta_len = ftello(delta_cache) - m->delta_offset;
424 		}
425 
426 		got_object_raw_close(raw);
427 		raw = NULL;
428 	}
429 done:
430 	for (i = MAX(0, nmeta - max_base_candidates); i < nmeta; i++) {
431 		got_deltify_free(meta[i]->dtab);
432 		meta[i]->dtab = NULL;
433 	}
434 	if (raw)
435 		got_object_raw_close(raw);
436 	if (base_raw)
437 		got_object_raw_close(base_raw);
438 	if (outfd != -1 && close(outfd) == -1 && err == NULL)
439 		err = got_error_from_errno("close");
440 	free(deltas);
441 	free(best_deltas);
442 	return err;
443 }
444 
445 static const struct got_error *
446 search_packidx(int *found, struct got_object_id *id,
447     struct got_repository *repo)
448 {
449 	const struct got_error *err = NULL;
450 	struct got_packidx *packidx = NULL;
451 	int idx;
452 
453 	*found = 0;
454 
455 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
456 	if (err == NULL)
457 		*found = 1; /* object is already packed */
458 	else if (err->code == GOT_ERR_NO_OBJ)
459 		err = NULL;
460 	return err;
461 }
462 
463 static const int obj_types[] = {
464 	GOT_OBJ_TYPE_ANY,
465 	GOT_OBJ_TYPE_COMMIT,
466 	GOT_OBJ_TYPE_TREE,
467 	GOT_OBJ_TYPE_BLOB,
468 	GOT_OBJ_TYPE_TAG,
469 	GOT_OBJ_TYPE_OFFSET_DELTA,
470 	GOT_OBJ_TYPE_REF_DELTA
471 };
472 
473 static const struct got_error *
474 add_meta(struct got_pack_metavec *v, struct got_object_idset *idset,
475     struct got_object_id *id, const char *path, int obj_type,
476     time_t mtime, int loose_obj_only, struct got_repository *repo)
477 {
478 	const struct got_error *err;
479 	struct got_pack_meta *m;
480 
481 	if (loose_obj_only) {
482 		int is_packed;
483 		err = search_packidx(&is_packed, id, repo);
484 		if (err)
485 			return err;
486 		if (is_packed)
487 			return NULL;
488 	}
489 
490 	err = got_object_idset_add(idset, id, (void *)&obj_types[obj_type]);
491 	if (err)
492 		return err;
493 
494 	if (v == NULL)
495 		return NULL;
496 
497 	err = alloc_meta(&m, id, path, obj_type, mtime);
498 	if (err)
499 		goto done;
500 
501 	if (v->nmeta == v->metasz){
502 		size_t newsize = 2 * v->metasz;
503 		struct got_pack_meta **new;
504 		new = reallocarray(v->meta, newsize, sizeof(*new));
505 		if (new == NULL) {
506 			err = got_error_from_errno("reallocarray");
507 			goto done;
508 		}
509 		v->meta = new;
510 		v->metasz = newsize; 
511 	}
512 done:
513 	if (err) {
514 		clear_meta(m);
515 		free(m);
516 	} else
517 		v->meta[v->nmeta++] = m;
518 
519 	return err;
520 }
521 
522 static const struct got_error *
523 load_tree_entries(struct got_object_id_queue *ids, struct got_pack_metavec *v,
524     struct got_object_idset *idset, struct got_object_id *tree_id,
525     const char *dpath, time_t mtime, struct got_repository *repo,
526     int loose_obj_only, got_cancel_cb cancel_cb, void *cancel_arg)
527 {
528 	const struct got_error *err;
529 	struct got_tree_object *tree;
530 	char *p = NULL;
531 	int i;
532 
533 	err = got_object_open_as_tree(&tree, repo, tree_id);
534 	if (err)
535 		return err;
536 
537 	for (i = 0; i < got_object_tree_get_nentries(tree); i++) {
538 		struct got_tree_entry *e = got_object_tree_get_entry(tree, i);
539 		struct got_object_id *id = got_tree_entry_get_id(e);
540 		mode_t mode = got_tree_entry_get_mode(e);
541 
542 		if (cancel_cb) {
543 			err = (*cancel_cb)(cancel_arg);
544 			if (err)
545 				break;
546 		}
547 
548 		if (got_object_tree_entry_is_submodule(e) ||
549 		    got_object_idset_contains(idset, id))
550 			continue;
551 		
552 		if (asprintf(&p, "%s%s%s", dpath, dpath[0] != '\0' ? "/" : "",
553 		    got_tree_entry_get_name(e)) == -1) {
554 			err = got_error_from_errno("asprintf");
555 			break;
556 		}
557 
558 		if (S_ISDIR(mode)) {
559 			struct got_object_qid *qid;
560 			err = got_object_qid_alloc(&qid, id);
561 			if (err)
562 				break;
563 			STAILQ_INSERT_TAIL(ids, qid, entry);
564 		} else if (S_ISREG(mode) || S_ISLNK(mode)) {
565 			err = add_meta(v, idset, id, p, GOT_OBJ_TYPE_BLOB,
566 			    mtime, loose_obj_only, repo);
567 			if (err)
568 				break;
569 		}
570 		free(p);
571 		p = NULL;
572 	}
573 
574 	got_object_tree_close(tree);
575 	free(p);
576 	return err;
577 }
578 
579 static const struct got_error *
580 load_tree(struct got_pack_metavec *v, struct got_object_idset *idset,
581     struct got_object_id *tree_id, const char *dpath, time_t mtime,
582     int loose_obj_only, struct got_repository *repo,
583     got_cancel_cb cancel_cb, void *cancel_arg)
584 {
585 	const struct got_error *err = NULL;
586 	struct got_object_id_queue tree_ids;
587 	struct got_object_qid *qid;
588 
589 	if (got_object_idset_contains(idset, tree_id))
590 		return NULL;
591 
592 	err = got_object_qid_alloc(&qid, tree_id);
593 	if (err)
594 		return err;
595 
596 	STAILQ_INIT(&tree_ids);
597 	STAILQ_INSERT_TAIL(&tree_ids, qid, entry);
598 
599 	while (!STAILQ_EMPTY(&tree_ids)) {
600 		if (cancel_cb) {
601 			err = (*cancel_cb)(cancel_arg);
602 			if (err)
603 				break;
604 		}
605 
606 		qid = STAILQ_FIRST(&tree_ids);
607 		STAILQ_REMOVE_HEAD(&tree_ids, entry);
608 
609 		if (got_object_idset_contains(idset, qid->id)) {
610 			got_object_qid_free(qid);
611 			continue;
612 		}
613 
614 		err = add_meta(v, idset, qid->id, dpath, GOT_OBJ_TYPE_TREE,
615 		    mtime, loose_obj_only, repo);
616 		if (err) {
617 			got_object_qid_free(qid);
618 			break;
619 		}
620 
621 		err = load_tree_entries(&tree_ids, v, idset, qid->id, dpath,
622 		    mtime, repo, loose_obj_only, cancel_cb, cancel_arg);
623 		got_object_qid_free(qid);
624 		if (err)
625 			break;
626 	}
627 
628 	got_object_id_queue_free(&tree_ids);
629 	return err;
630 }
631 
632 static const struct got_error *
633 load_commit(struct got_pack_metavec *v, struct got_object_idset *idset,
634     struct got_object_id *id, struct got_repository *repo, int loose_obj_only,
635     got_cancel_cb cancel_cb, void *cancel_arg)
636 {
637 	const struct got_error *err;
638 	struct got_commit_object *commit;
639 
640 	if (got_object_idset_contains(idset, id))
641 		return NULL;
642 
643 	if (loose_obj_only) {
644 		int is_packed;
645 		err = search_packidx(&is_packed, id, repo);
646 		if (err)
647 			return err;
648 		if (is_packed)
649 			return NULL;
650 	}
651 
652 	err = got_object_open_as_commit(&commit, repo, id);
653 	if (err)
654 		return err;
655 
656 	err = add_meta(v, idset, id, "", GOT_OBJ_TYPE_COMMIT,
657 	    got_object_commit_get_committer_time(commit),
658 	    loose_obj_only, repo);
659 	if (err)
660 		goto done;
661 
662 	err = load_tree(v, idset, got_object_commit_get_tree_id(commit),
663 	    "", got_object_commit_get_committer_time(commit),
664 	    loose_obj_only, repo, cancel_cb, cancel_arg);
665 done:
666 	got_object_commit_close(commit);
667 	return err;
668 }
669 
670 static const struct got_error *
671 load_tag(struct got_pack_metavec *v, struct got_object_idset *idset,
672     struct got_object_id *id, struct got_repository *repo, int loose_obj_only,
673     got_cancel_cb cancel_cb, void *cancel_arg)
674 {
675 	const struct got_error *err;
676 	struct got_tag_object *tag = NULL;
677 
678 	if (got_object_idset_contains(idset, id))
679 		return NULL;
680 
681 	if (loose_obj_only) {
682 		int is_packed;
683 		err = search_packidx(&is_packed, id, repo);
684 		if (err)
685 			return err;
686 		if (is_packed)
687 			return NULL;
688 	}
689 
690 	err = got_object_open_as_tag(&tag, repo, id);
691 	if (err)
692 		return err;
693 
694 	err = add_meta(v, idset, id, "", GOT_OBJ_TYPE_TAG,
695 	    got_object_tag_get_tagger_time(tag),
696 	    loose_obj_only, repo);
697 	if (err)
698 		goto done;
699 
700 	switch (got_object_tag_get_object_type(tag)) {
701 	case GOT_OBJ_TYPE_COMMIT:
702 		err = load_commit(v, idset,
703 		    got_object_tag_get_object_id(tag), repo,
704 		    loose_obj_only, cancel_cb, cancel_arg);
705 		break;
706 	case GOT_OBJ_TYPE_TREE:
707 		err = load_tree(v, idset, got_object_tag_get_object_id(tag),
708 		    "", got_object_tag_get_tagger_time(tag),
709 		    loose_obj_only, repo, cancel_cb, cancel_arg);
710 		break;
711 	default:
712 		break;
713 	}
714 
715 done:
716 	got_object_tag_close(tag);
717 	return err;
718 }
719 
720 enum findtwixt_color {
721 	COLOR_KEEP = 0,
722 	COLOR_DROP,
723 	COLOR_BLANK,
724 };
725 static const int findtwixt_colors[] = {
726 	COLOR_KEEP,
727 	COLOR_DROP,
728 	COLOR_BLANK
729 };
730 
731 static const struct got_error *
732 queue_commit_id(struct got_object_id_queue *ids, struct got_object_id *id,
733     int color, struct got_repository *repo)
734 {
735 	const struct got_error *err;
736 	struct got_object_qid *qid;
737 
738 	err = got_object_qid_alloc(&qid, id);
739 	if (err)
740 		return err;
741 
742 	STAILQ_INSERT_TAIL(ids, qid, entry);
743 	qid->data = (void *)&findtwixt_colors[color];
744 	return NULL;
745 }
746 
747 static const struct got_error *
748 drop_commit(struct got_object_idset *keep, struct got_object_idset *drop,
749     struct got_object_id *id, struct got_repository *repo,
750     got_cancel_cb cancel_cb, void *cancel_arg)
751 {
752 	const struct got_error *err = NULL;
753 	struct got_commit_object *commit;
754 	const struct got_object_id_queue *parents;
755 	struct got_object_id_queue ids;
756 	struct got_object_qid *qid;
757 
758 	STAILQ_INIT(&ids);
759 
760 	err = got_object_qid_alloc(&qid, id);
761 	if (err)
762 		return err;
763 	STAILQ_INSERT_HEAD(&ids, qid, entry);
764 
765 	while (!STAILQ_EMPTY(&ids)) {
766 		if (cancel_cb) {
767 			err = (*cancel_cb)(cancel_arg);
768 			if (err)
769 				break;
770 		}
771 
772 		qid = STAILQ_FIRST(&ids);
773 		STAILQ_REMOVE_HEAD(&ids, entry);
774 
775 		if (got_object_idset_contains(drop, qid->id)) {
776 			got_object_qid_free(qid);
777 			continue;
778 		}
779 
780 		err = got_object_idset_add(drop, qid->id,
781 		    (void *)&obj_types[GOT_OBJ_TYPE_COMMIT]);
782 		if (err) {
783 			got_object_qid_free(qid);
784 			break;
785 		}
786 
787 		if (!got_object_idset_contains(keep, qid->id)) {
788 			got_object_qid_free(qid);
789 			continue;
790 		}
791 
792 		err = got_object_open_as_commit(&commit, repo, qid->id);
793 		got_object_qid_free(qid);
794 		if (err)
795 			break;
796 
797 		parents = got_object_commit_get_parent_ids(commit);
798 		if (parents) {
799 			err = got_object_id_queue_copy(parents, &ids);
800 			if (err) {
801 				got_object_commit_close(commit);
802 				break;
803 			}
804 		}
805 		got_object_commit_close(commit);
806 	}
807 
808 	got_object_id_queue_free(&ids);
809 	return err;
810 }
811 
812 struct append_id_arg {
813 	struct got_object_id **array;
814 	int idx;
815 };
816 
817 static const struct got_error *
818 append_id(struct got_object_id *id, void *data, void *arg)
819 {
820 	struct append_id_arg *a = arg;
821 
822 	a->array[a->idx] = got_object_id_dup(id);
823 	if (a->array[a->idx] == NULL)
824 		return got_error_from_errno("got_object_id_dup");
825 
826 	a->idx++;
827 	return NULL;
828 }
829 
830 static const struct got_error *
831 findtwixt(struct got_object_id ***res, int *nres,
832     struct got_object_id **head, int nhead,
833     struct got_object_id **tail, int ntail,
834     struct got_repository *repo,
835     got_cancel_cb cancel_cb, void *cancel_arg)
836 {
837 	const struct got_error *err = NULL;
838 	struct got_object_id_queue ids;
839 	struct got_object_idset *keep, *drop;
840 	struct got_object_qid *qid;
841 	int i, ncolor, nkeep, obj_type;
842 
843 	STAILQ_INIT(&ids);
844 	*res = NULL;
845 	*nres = 0;
846 
847 	keep = got_object_idset_alloc();
848 	if (keep == NULL)
849 		return got_error_from_errno("got_object_idset_alloc");
850 
851 	drop = got_object_idset_alloc();
852 	if (drop == NULL) {
853 		err = got_error_from_errno("got_object_idset_alloc");
854 		goto done;
855 	}
856 
857 	for (i = 0; i < nhead; i++) {
858 		struct got_object_id *id = head[i];
859 		if (id == NULL)
860 			continue;
861 		err = got_object_get_type(&obj_type, repo, id);
862 		if (err)
863 			return err;
864 		if (obj_type != GOT_OBJ_TYPE_COMMIT)
865 			continue;
866 		err = queue_commit_id(&ids, id, COLOR_KEEP, repo);
867 		if (err)
868 			goto done;
869 	}		
870 	for (i = 0; i < ntail; i++) {
871 		struct got_object_id *id = tail[i];
872 		if (id == NULL)
873 			continue;
874 		err = got_object_get_type(&obj_type, repo, id);
875 		if (err)
876 			return err;
877 		if (obj_type != GOT_OBJ_TYPE_COMMIT)
878 			continue;
879 		err = queue_commit_id(&ids, id, COLOR_DROP, repo);
880 		if (err)
881 			goto done;
882 	}
883 
884 	while (!STAILQ_EMPTY(&ids)) {
885 		int qcolor;
886 		qid = STAILQ_FIRST(&ids);
887 		qcolor = *((int *)qid->data);
888 
889 		if (got_object_idset_contains(drop, qid->id))
890 			ncolor = COLOR_DROP;
891 		else if (got_object_idset_contains(keep, qid->id))
892 			ncolor = COLOR_KEEP;
893 		else
894 			ncolor = COLOR_BLANK;
895 
896 		if (ncolor == COLOR_DROP || (ncolor == COLOR_KEEP &&
897 		    qcolor == COLOR_KEEP)) {
898 			STAILQ_REMOVE_HEAD(&ids, entry);
899 			got_object_qid_free(qid);
900 			continue;
901 		}
902 
903 		if (ncolor == COLOR_KEEP && qcolor == COLOR_DROP) {
904 			err = drop_commit(keep, drop, qid->id, repo,
905 			    cancel_cb, cancel_arg);
906 			if (err)
907 				goto done;
908 		} else if (ncolor == COLOR_BLANK) {
909 			struct got_commit_object *commit;
910 			struct got_object_id *id;
911 			const struct got_object_id_queue *parents;
912 			struct got_object_qid *pid;
913 
914 			id = got_object_id_dup(qid->id);
915 			if (id == NULL) {
916 				err = got_error_from_errno("got_object_id_dup");
917 				goto done;
918 			}
919 			if (qcolor == COLOR_KEEP)
920 				err = got_object_idset_add(keep, id,
921 				    (void *)&obj_types[GOT_OBJ_TYPE_COMMIT]);
922 			else
923 				err = got_object_idset_add(drop, id,
924 				    (void *)&obj_types[GOT_OBJ_TYPE_COMMIT]);
925 			if (err) {
926 				free(id);
927 				goto done;
928 			}
929 
930 			err = got_object_open_as_commit(&commit, repo, id);
931 			if (err) {
932 				free(id);
933 				goto done;
934 			}
935 			parents = got_object_commit_get_parent_ids(commit);
936 			if (parents) {
937 				STAILQ_FOREACH(pid, parents, entry) {
938 					err = queue_commit_id(&ids, pid->id,
939 					    qcolor, repo);
940 					if (err) {
941 						free(id);
942 						goto done;
943 					}
944 				}
945 			}
946 			got_object_commit_close(commit);
947 			commit = NULL;
948 		} else {
949 			/* should not happen */
950 			err = got_error_fmt(GOT_ERR_NOT_IMPL,
951 			    "%s ncolor=%d qcolor=%d", __func__, ncolor, qcolor);
952 			goto done;
953 		}
954 
955 		STAILQ_REMOVE_HEAD(&ids, entry);
956 		got_object_qid_free(qid);
957 	}
958 
959 	nkeep = got_object_idset_num_elements(keep);
960 	if (nkeep > 0) {
961 		struct append_id_arg arg;
962 		arg.array = calloc(nkeep, sizeof(struct got_object_id *));
963 		if (arg.array == NULL) {
964 			err = got_error_from_errno("calloc");
965 			goto done;
966 		}
967 		arg.idx = 0;
968 		err = got_object_idset_for_each(keep, append_id, &arg);
969 		if (err) {
970 			free(arg.array);
971 			goto done;
972 		}
973 		*res = arg.array;
974 		*nres = nkeep;
975 	}
976 done:
977 	got_object_idset_free(keep);
978 	got_object_idset_free(drop);
979 	got_object_id_queue_free(&ids);
980 	return err;
981 }
982 
983 static const struct got_error *
984 read_meta(struct got_pack_meta ***meta, int *nmeta,
985     struct got_object_id **theirs, int ntheirs,
986     struct got_object_id **ours, int nours, struct got_repository *repo,
987     int loose_obj_only, got_pack_progress_cb progress_cb, void *progress_arg,
988     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
989 {
990 	const struct got_error *err = NULL;
991 	struct got_object_id **ids = NULL;
992 	struct got_object_idset *idset;
993 	int i, nobj = 0, obj_type;
994 	struct got_pack_metavec v;
995 
996 	*meta = NULL;
997 	*nmeta = 0;
998 
999 	idset = got_object_idset_alloc();
1000 	if (idset == NULL)
1001 		return got_error_from_errno("got_object_idset_alloc");
1002 
1003 	v.nmeta = 0;
1004 	v.metasz = 64;
1005 	v.meta = calloc(v.metasz, sizeof(struct got_pack_meta *));
1006 	if (v.meta == NULL) {
1007 		err = got_error_from_errno("calloc");
1008 		goto done;
1009 	}
1010 
1011 	err = findtwixt(&ids, &nobj, ours, nours, theirs, ntheirs, repo,
1012 	    cancel_cb, cancel_arg);
1013 	if (err || nobj == 0)
1014 		goto done;
1015 
1016 	for (i = 0; i < ntheirs; i++) {
1017 		struct got_object_id *id = theirs[i];
1018 		if (id == NULL)
1019 			continue;
1020 		err = got_object_get_type(&obj_type, repo, id);
1021 		if (err)
1022 			return err;
1023 		if (obj_type != GOT_OBJ_TYPE_COMMIT)
1024 			continue;
1025 		err = load_commit(NULL, idset, id, repo,
1026 		    loose_obj_only, cancel_cb, cancel_arg);
1027 		if (err)
1028 			goto done;
1029 		err = report_progress(progress_cb, progress_arg, rl,
1030 		    0L, nours, v.nmeta, 0, 0);
1031 		if (err)
1032 			goto done;
1033 	}
1034 
1035 	for (i = 0; i < ntheirs; i++) {
1036 		struct got_object_id *id = theirs[i];
1037 		int *cached_type;
1038 		if (id == NULL)
1039 			continue;
1040 		cached_type = got_object_idset_get(idset, id);
1041 		if (cached_type == NULL) {
1042 			err = got_object_get_type(&obj_type, repo, id);
1043 			if (err)
1044 				goto done;
1045 		} else
1046 			obj_type = *cached_type;
1047 		if (obj_type != GOT_OBJ_TYPE_TAG)
1048 			continue;
1049 		err = load_tag(NULL, idset, id, repo,
1050 		    loose_obj_only, cancel_cb, cancel_arg);
1051 		if (err)
1052 			goto done;
1053 		err = report_progress(progress_cb, progress_arg, rl,
1054 		    0L, nours, v.nmeta, 0, 0);
1055 		if (err)
1056 			goto done;
1057 	}
1058 
1059 	for (i = 0; i < nobj; i++) {
1060 		err = load_commit(&v, idset, ids[i], repo,
1061 		    loose_obj_only, cancel_cb, cancel_arg);
1062 		if (err)
1063 			goto done;
1064 		if (err)
1065 			goto done;
1066 		err = report_progress(progress_cb, progress_arg, rl,
1067 		    0L, nours, v.nmeta, 0, 0);
1068 		if (err)
1069 			goto done;
1070 	}
1071 
1072 	for (i = 0; i < nours; i++) {
1073 		struct got_object_id *id = ours[i];
1074 		int *cached_type;
1075 		if (id == NULL)
1076 			continue;
1077 		cached_type = got_object_idset_get(idset, id);
1078 		if (cached_type == NULL) {
1079 			err = got_object_get_type(&obj_type, repo, id);
1080 			if (err)
1081 				goto done;
1082 		} else
1083 			obj_type = *cached_type;
1084 		if (obj_type != GOT_OBJ_TYPE_TAG)
1085 			continue;
1086 		err = load_tag(&v, idset, id, repo,
1087 		    loose_obj_only, cancel_cb, cancel_arg);
1088 		if (err)
1089 			goto done;
1090 		err = report_progress(progress_cb, progress_arg, rl,
1091 		    0L, nours, v.nmeta, 0, 0);
1092 		if (err)
1093 			goto done;
1094 	}
1095 
1096 	if (progress_cb) {
1097 		err = progress_cb(progress_arg, 0L, nours, v.nmeta, 0, 0);
1098 		if (err)
1099 			goto done;
1100 	}
1101 done:
1102 	for (i = 0; i < nobj; i++) {
1103 		free(ids[i]);
1104 	}
1105 	free(ids);
1106 	got_object_idset_free(idset);
1107 	if (err == NULL) {
1108 		*meta = v.meta;
1109 		*nmeta = v.nmeta;
1110 	} else
1111 		free(v.meta);
1112 
1113 	return err;
1114 }
1115 
1116 const struct got_error *
1117 hwrite(FILE *f, void *buf, int len, SHA1_CTX *ctx)
1118 {
1119 	size_t n;
1120 
1121 	SHA1Update(ctx, buf, len);
1122 	n = fwrite(buf, 1, len, f);
1123 	if (n != len)
1124 		return got_ferror(f, GOT_ERR_IO);
1125 	return NULL;
1126 }
1127 
1128 static void
1129 putbe32(char *b, uint32_t n)
1130 {
1131 	b[0] = n >> 24;
1132 	b[1] = n >> 16;
1133 	b[2] = n >> 8;
1134 	b[3] = n >> 0;
1135 }
1136 
1137 static int
1138 write_order_cmp(const void *pa, const void *pb)
1139 {
1140 	struct got_pack_meta *a, *b, *ahd, *bhd;
1141 
1142 	a = *(struct got_pack_meta **)pa;
1143 	b = *(struct got_pack_meta **)pb;
1144 	ahd = (a->head == NULL) ? a : a->head;
1145 	bhd = (b->head == NULL) ? b : b->head;
1146 	if (ahd->mtime != bhd->mtime)
1147 		return bhd->mtime - ahd->mtime;
1148 	if (ahd != bhd)
1149 		return (uintptr_t)bhd - (uintptr_t)ahd;
1150 	if (a->nchain != b->nchain)
1151 		return a->nchain - b->nchain;
1152 	return a->mtime - b->mtime;
1153 }
1154 
1155 static const struct got_error *
1156 packhdr(int *hdrlen, char *hdr, size_t bufsize, int obj_type, size_t len)
1157 {
1158 	size_t i;
1159 
1160 	*hdrlen = 0;
1161 
1162 	hdr[0] = obj_type << 4;
1163 	hdr[0] |= len & 0xf;
1164 	len >>= 4;
1165 	for (i = 1; len != 0; i++){
1166 		if (i >= bufsize)
1167 			return got_error(GOT_ERR_NO_SPACE);
1168 		hdr[i - 1] |= GOT_DELTA_SIZE_MORE;
1169 		hdr[i] = len & GOT_DELTA_SIZE_VAL_MASK;
1170 		len >>= GOT_DELTA_SIZE_SHIFT;
1171 	}
1172 
1173 	*hdrlen = i;
1174 	return NULL;
1175 }
1176 
1177 static int
1178 packoff(char *hdr, off_t off)
1179 {
1180 	int i, j;
1181 	char rbuf[8];
1182 
1183 	rbuf[0] = off & GOT_DELTA_SIZE_VAL_MASK;
1184 	for (i = 1; (off >>= GOT_DELTA_SIZE_SHIFT) != 0; i++) {
1185 		rbuf[i] = (--off & GOT_DELTA_SIZE_VAL_MASK) |
1186 		    GOT_DELTA_SIZE_MORE;
1187 	}
1188 
1189 	j = 0;
1190 	while (i > 0)
1191 		hdr[j++] = rbuf[--i];
1192 	return j;
1193 }
1194 
1195 static const struct got_error *
1196 genpack(uint8_t *pack_sha1, FILE *packfile, FILE *delta_cache,
1197     struct got_pack_meta **meta, int nmeta, int nours,
1198     int use_offset_deltas, struct got_repository *repo,
1199     got_pack_progress_cb progress_cb, void *progress_arg,
1200     struct got_ratelimit *rl,
1201     got_cancel_cb cancel_cb, void *cancel_arg)
1202 {
1203 	const struct got_error *err = NULL;
1204 	int i, nh;
1205 	SHA1_CTX ctx;
1206 	struct got_pack_meta *m;
1207 	struct got_raw_object *raw = NULL;
1208 	FILE *delta_file = NULL;
1209 	char buf[32];
1210 	size_t outlen, n;
1211 	struct got_deflate_checksum csum;
1212 	off_t packfile_size = 0;
1213 	int outfd = -1;
1214 
1215 	SHA1Init(&ctx);
1216 	csum.output_sha1 = &ctx;
1217 	csum.output_crc = NULL;
1218 
1219 	err = hwrite(packfile, "PACK", 4, &ctx);
1220 	if (err)
1221 		return err;
1222 	putbe32(buf, GOT_PACKFILE_VERSION);
1223 	err = hwrite(packfile, buf, 4, &ctx);
1224 	if (err)
1225 		goto done;
1226 	putbe32(buf, nmeta);
1227 	err = hwrite(packfile, buf, 4, &ctx);
1228 	if (err)
1229 		goto done;
1230 	qsort(meta, nmeta, sizeof(struct got_pack_meta *), write_order_cmp);
1231 	for (i = 0; i < nmeta; i++) {
1232 		err = report_progress(progress_cb, progress_arg, rl,
1233 		    packfile_size, nours, nmeta, nmeta, i);
1234 		if (err)
1235 			goto done;
1236 		m = meta[i];
1237 		m->off = ftello(packfile);
1238 		if (m->delta_len == 0) {
1239 			err = got_object_raw_open(&raw, &outfd, repo, &m->id);
1240 			if (err)
1241 				goto done;
1242 			err = packhdr(&nh, buf, sizeof(buf),
1243 			    m->obj_type, raw->size);
1244 			if (err)
1245 				goto done;
1246 			err = hwrite(packfile, buf, nh, &ctx);
1247 			if (err)
1248 				goto done;
1249 			packfile_size += nh;
1250 			if (raw->f == NULL) {
1251 				err = got_deflate_to_file_mmap(&outlen,
1252 				    raw->data + raw->hdrlen, 0, raw->size,
1253 				    packfile, &csum);
1254 				if (err)
1255 					goto done;
1256 			} else {
1257 				if (fseeko(raw->f, raw->hdrlen, SEEK_SET)
1258 				    == -1) {
1259 					err = got_error_from_errno("fseeko");
1260 					goto done;
1261 				}
1262 				err = got_deflate_to_file(&outlen, raw->f,
1263 				    packfile, &csum);
1264 				if (err)
1265 					goto done;
1266 			}
1267 			packfile_size += outlen;
1268 			got_object_raw_close(raw);
1269 			raw = NULL;
1270 		} else {
1271 			off_t remain;
1272 			if (delta_file == NULL) {
1273 				delta_file = got_opentemp();
1274 				if (delta_file == NULL) {
1275 					err = got_error_from_errno(
1276 					    "got_opentemp");
1277 					goto done;
1278 				}
1279 			}
1280 			if (ftruncate(fileno(delta_file), 0L) == -1) {
1281 				err = got_error_from_errno("ftruncate");
1282 				goto done;
1283 			}
1284 			if (fseeko(delta_file, 0L, SEEK_SET) == -1) {
1285 				err = got_error_from_errno("fseeko");
1286 				goto done;
1287 			}
1288 			if (fseeko(delta_cache, m->delta_offset, SEEK_SET)
1289 			    == -1) {
1290 				err = got_error_from_errno("fseeko");
1291 				goto done;
1292 			}
1293 			remain = m->delta_len;
1294 			while (remain > 0) {
1295 				char delta_buf[8192];
1296 				size_t r, w, n;
1297 				n = MIN(remain, sizeof(delta_buf));
1298 				r = fread(delta_buf, 1, n, delta_cache);
1299 				if (r != n) {
1300 					err = got_ferror(delta_cache,
1301 					    GOT_ERR_IO);
1302 					goto done;
1303 				}
1304 				w = fwrite(delta_buf, 1, n, delta_file);
1305 				if (w != n) {
1306 					err = got_ferror(delta_file,
1307 					    GOT_ERR_IO);
1308 					goto done;
1309 				}
1310 				remain -= n;
1311 			}
1312 			if (use_offset_deltas && m->prev->off != 0) {
1313 				err = packhdr(&nh, buf, sizeof(buf),
1314 				    GOT_OBJ_TYPE_OFFSET_DELTA, m->delta_len);
1315 				if (err)
1316 					goto done;
1317 				nh += packoff(buf + nh,
1318 				    m->off - m->prev->off);
1319 				err = hwrite(packfile, buf, nh, &ctx);
1320 				if (err)
1321 					goto done;
1322 				packfile_size += nh;
1323 			} else {
1324 				err = packhdr(&nh, buf, sizeof(buf),
1325 				    GOT_OBJ_TYPE_REF_DELTA, m->delta_len);
1326 				err = hwrite(packfile, buf, nh, &ctx);
1327 				if (err)
1328 					goto done;
1329 				packfile_size += nh;
1330 				err = hwrite(packfile, m->prev->id.sha1,
1331 				    sizeof(m->prev->id.sha1), &ctx);
1332 				packfile_size += sizeof(m->prev->id.sha1);
1333 				if (err)
1334 					goto done;
1335 			}
1336 			if (fseeko(delta_file, 0L, SEEK_SET) == -1) {
1337 				err = got_error_from_errno("fseeko");
1338 				goto done;
1339 			}
1340 			err = got_deflate_to_file(&outlen, delta_file,
1341 			    packfile, &csum);
1342 			if (err)
1343 				goto done;
1344 			packfile_size += outlen;
1345 		}
1346 	}
1347 	SHA1Final(pack_sha1, &ctx);
1348 	n = fwrite(pack_sha1, 1, SHA1_DIGEST_LENGTH, packfile);
1349 	if (n != SHA1_DIGEST_LENGTH)
1350 		err = got_ferror(packfile, GOT_ERR_IO);
1351 	packfile_size += SHA1_DIGEST_LENGTH;
1352 	packfile_size += sizeof(struct got_packfile_hdr);
1353 	if (progress_cb) {
1354 		err = progress_cb(progress_arg, packfile_size, nours,
1355 		    nmeta, nmeta, nmeta);
1356 		if (err)
1357 			goto done;
1358 	}
1359 done:
1360 	if (delta_file && fclose(delta_file) == EOF && err == NULL)
1361 		err = got_error_from_errno("fclose");
1362 	if (raw)
1363 		got_object_raw_close(raw);
1364 	if (outfd != -1 && close(outfd) == -1 && err == NULL)
1365 		err = got_error_from_errno("close");
1366 	return err;
1367 }
1368 
1369 const struct got_error *
1370 got_pack_create(uint8_t *packsha1, FILE *packfile,
1371     struct got_object_id **theirs, int ntheirs,
1372     struct got_object_id **ours, int nours,
1373     struct got_repository *repo, int loose_obj_only, int allow_empty,
1374     got_pack_progress_cb progress_cb, void *progress_arg,
1375     got_cancel_cb cancel_cb, void *cancel_arg)
1376 {
1377 	const struct got_error *err;
1378 	struct got_pack_meta **meta;
1379 	int nmeta;
1380 	FILE *delta_cache = NULL;
1381 	struct got_ratelimit rl;
1382 
1383 	got_ratelimit_init(&rl, 0, 500);
1384 
1385 	err = read_meta(&meta, &nmeta, theirs, ntheirs, ours, nours, repo,
1386 	    loose_obj_only, progress_cb, progress_arg, &rl,
1387 	    cancel_cb, cancel_arg);
1388 	if (err)
1389 		return err;
1390 
1391 	if (nmeta == 0 && !allow_empty) {
1392 		err = got_error(GOT_ERR_CANNOT_PACK);
1393 		goto done;
1394 	}
1395 
1396 	delta_cache = got_opentemp();
1397 	if (delta_cache == NULL) {
1398 		err = got_error_from_errno("got_opentemp");
1399 		goto done;
1400 	}
1401 
1402 	if (nmeta > 0) {
1403 		err = pick_deltas(meta, nmeta, nours, delta_cache, repo,
1404 		    progress_cb, progress_arg, &rl, cancel_cb, cancel_arg);
1405 		if (err)
1406 			goto done;
1407 		if (fseeko(delta_cache, 0L, SEEK_SET) == -1) {
1408 			err = got_error_from_errno("fseeko");
1409 			goto done;
1410 		}
1411 	}
1412 
1413 	err = genpack(packsha1, packfile, delta_cache, meta, nmeta, nours, 1,
1414 	    repo, progress_cb, progress_arg, &rl, cancel_cb, cancel_arg);
1415 	if (err)
1416 		goto done;
1417 done:
1418 	free_nmeta(meta, nmeta);
1419 	if (delta_cache && fclose(delta_cache) == EOF && err == NULL)
1420 		err = got_error_from_errno("fclose");
1421 	return err;
1422 }