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 #include <sys/mman.h>
25 
26 #include <endian.h>
27 #include <errno.h>
28 #include <stdint.h>
29 #include <imsg.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <sha1.h>
34 #include <time.h>
35 #include <unistd.h>
36 #include <limits.h>
37 #include <zlib.h>
38 
39 #include "got_error.h"
40 #include "got_cancel.h"
41 #include "got_object.h"
42 #include "got_path.h"
43 #include "got_reference.h"
44 #include "got_repository_admin.h"
45 #include "got_opentemp.h"
46 
47 #include "got_lib_deltify.h"
48 #include "got_lib_delta.h"
49 #include "got_lib_object.h"
50 #include "got_lib_object_idset.h"
51 #include "got_lib_object_cache.h"
52 #include "got_lib_deflate.h"
53 #include "got_lib_pack.h"
54 #include "got_lib_pack_create.h"
55 #include "got_lib_privsep.h"
56 #include "got_lib_repository.h"
57 #include "got_lib_ratelimit.h"
58 #include "got_lib_inflate.h"
59 
60 #include "murmurhash2.h"
61 
62 #ifndef MIN
63 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
64 #endif
65 
66 #ifndef MAX
67 #define	MAX(_a,_b) ((_a) > (_b) ? (_a) : (_b))
68 #endif
69 
70 #ifndef nitems
71 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
72 #endif
73 
74 struct got_pack_meta {
75 	struct got_object_id id;
76 	uint32_t path_hash;
77 	int	obj_type;
78 	off_t	size;
79 	time_t	mtime;
80 
81 	/* The best delta we picked */
82 	struct got_pack_meta *head;
83 	struct got_pack_meta *prev;
84 	unsigned char *delta_buf; /* if encoded in memory (compressed) */
85 	off_t	delta_offset;	/* offset in delta cache file (compressed) */
86 	off_t	delta_len;	/* encoded delta length */
87 	off_t	delta_compressed_len; /* encoded+compressed delta length */
88 	int	nchain;
89 
90 	off_t   reused_delta_offset; /* offset of delta in reused pack file */
91 	struct got_object_id *base_obj_id;
92 
93 	/* Only used for delta window */
94 	struct got_delta_table *dtab;
95 
96 	/* Only used for writing offset deltas */
97 	off_t	off;
98 };
99 
100 struct got_pack_metavec {
101 	struct got_pack_meta **meta;
102 	int nmeta;
103 	int metasz;
104 };
105 
106 static const struct got_error *
107 alloc_meta(struct got_pack_meta **new, struct got_object_id *id,
108     const char *path, int obj_type, time_t mtime, uint32_t seed)
109 {
110 	struct got_pack_meta *m;
111 
112 	*new = NULL;
113 
114 	m = calloc(1, sizeof(*m));
115 	if (m == NULL)
116 		return got_error_from_errno("calloc");
117 
118 	memcpy(&m->id, id, sizeof(m->id));
119 
120 	m->path_hash = murmurhash2(path, strlen(path), seed);
121 	m->obj_type = obj_type;
122 	m->mtime = mtime;
123 	*new = m;
124 	return NULL;
125 }
126 
127 static void
128 clear_meta(struct got_pack_meta *meta)
129 {
130 	if (meta == NULL)
131 		return;
132 	meta->path_hash = 0;
133 	free(meta->delta_buf);
134 	meta->delta_buf = NULL;
135 	free(meta->base_obj_id);
136 	meta->base_obj_id = NULL;
137 	meta->reused_delta_offset = 0;
138 }
139 
140 static void
141 free_nmeta(struct got_pack_meta **meta, int nmeta)
142 {
143 	int i;
144 
145 	for (i = 0; i < nmeta; i++)
146 		clear_meta(meta[i]);
147 	free(meta);
148 }
149 
150 static int
151 delta_order_cmp(const void *pa, const void *pb)
152 {
153 	struct got_pack_meta *a, *b;
154 
155 	a = *(struct got_pack_meta **)pa;
156 	b = *(struct got_pack_meta **)pb;
157 
158 	if (a->obj_type != b->obj_type)
159 		return a->obj_type - b->obj_type;
160 	if (a->path_hash < b->path_hash)
161 		return -1;
162 	if (a->path_hash > b->path_hash)
163 		return 1;
164 	if (a->mtime < b->mtime)
165 		return -1;
166 	if (a->mtime > b->mtime)
167 		return 1;
168 	return got_object_id_cmp(&a->id, &b->id);
169 }
170 
171 static off_t
172 delta_size(struct got_delta_instruction *deltas, int ndeltas)
173 {
174 	int i;
175 	off_t size = 32;
176 	for (i = 0; i < ndeltas; i++) {
177 		if (deltas[i].copy)
178 			size += GOT_DELTA_SIZE_SHIFT;
179 		else
180 			size += deltas[i].len + 1;
181 	}
182 	return size;
183 }
184 
185 static const struct got_error *
186 append(unsigned char **p, size_t *len, off_t *sz, void *seg, int nseg)
187 {
188 	char *n;
189 
190 	if (*len + nseg >= *sz) {
191 		while (*len + nseg >= *sz)
192 			*sz += *sz / 2;
193 		n = realloc(*p, *sz);
194 		if (n == NULL)
195 			return got_error_from_errno("realloc");
196 		*p = n;
197 	}
198 	memcpy(*p + *len, seg, nseg);
199 	*len += nseg;
200 	return NULL;
201 }
202 
203 static const struct got_error *
204 encode_delta_in_mem(struct got_pack_meta *m, struct got_raw_object *o,
205     struct got_delta_instruction *deltas, int ndeltas,
206     off_t delta_size, off_t base_size)
207 {
208 	const struct got_error *err;
209 	unsigned char buf[16], *bp;
210 	int i, j;
211 	size_t len = 0, compressed_len;
212 	off_t bufsize = delta_size;
213 	off_t n;
214 	struct got_delta_instruction *d;
215 	uint8_t *delta_buf;
216 
217 	delta_buf = malloc(bufsize);
218 	if (delta_buf == NULL)
219 		return got_error_from_errno("malloc");
220 
221 	/* base object size */
222 	buf[0] = base_size & GOT_DELTA_SIZE_VAL_MASK;
223 	n = base_size >> GOT_DELTA_SIZE_SHIFT;
224 	for (i = 1; n > 0; i++) {
225 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
226 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
227 		n >>= GOT_DELTA_SIZE_SHIFT;
228 	}
229 	err = append(&delta_buf, &len, &bufsize, buf, i);
230 	if (err)
231 		goto done;
232 
233 	/* target object size */
234 	buf[0] = o->size & GOT_DELTA_SIZE_VAL_MASK;
235 	n = o->size >> GOT_DELTA_SIZE_SHIFT;
236 	for (i = 1; n > 0; i++) {
237 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
238 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
239 		n >>= GOT_DELTA_SIZE_SHIFT;
240 	}
241 	err = append(&delta_buf, &len, &bufsize, buf, i);
242 	if (err)
243 		goto done;
244 
245 	for (j = 0; j < ndeltas; j++) {
246 		d = &deltas[j];
247 		if (d->copy) {
248 			n = d->offset;
249 			bp = &buf[1];
250 			buf[0] = GOT_DELTA_BASE_COPY;
251 			for (i = 0; i < 4; i++) {
252 				/* DELTA_COPY_OFF1 ... DELTA_COPY_OFF4 */
253 				buf[0] |= 1 << i;
254 				*bp++ = n & 0xff;
255 				n >>= 8;
256 				if (n == 0)
257 					break;
258 			}
259 
260 			n = d->len;
261 			if (n != GOT_DELTA_COPY_DEFAULT_LEN) {
262 				/* DELTA_COPY_LEN1 ... DELTA_COPY_LEN3 */
263 				for (i = 0; i < 3 && n > 0; i++) {
264 					buf[0] |= 1 << (i + 4);
265 					*bp++ = n & 0xff;
266 					n >>= 8;
267 				}
268 			}
269 			err = append(&delta_buf, &len, &bufsize,
270 			    buf, bp - buf);
271 			if (err)
272 				goto done;
273 		} else if (o->f == NULL) {
274 			n = 0;
275 			while (n != d->len) {
276 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
277 				err = append(&delta_buf, &len, &bufsize,
278 				    buf, 1);
279 				if (err)
280 					goto done;
281 				err = append(&delta_buf, &len, &bufsize,
282 				    o->data + o->hdrlen + d->offset + n,
283 				    buf[0]);
284 				if (err)
285 					goto done;
286 				n += buf[0];
287 			}
288 		} else {
289 			char content[128];
290 			size_t r;
291 			if (fseeko(o->f, o->hdrlen + d->offset, SEEK_SET) == -1) {
292 				err = got_error_from_errno("fseeko");
293 				goto done;
294 			}
295 			n = 0;
296 			while (n != d->len) {
297 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
298 				err = append(&delta_buf, &len, &bufsize,
299 				    buf, 1);
300 				if (err)
301 					goto done;
302 				r = fread(content, 1, buf[0], o->f);
303 				if (r != buf[0]) {
304 					err = got_ferror(o->f, GOT_ERR_IO);
305 					goto done;
306 				}
307 				err = append(&delta_buf, &len, &bufsize,
308 				    content, buf[0]);
309 				if (err)
310 					goto done;
311 				n += buf[0];
312 			}
313 		}
314 	}
315 
316 	err = got_deflate_to_mem_mmap(&m->delta_buf, &compressed_len,
317 	    NULL, NULL, delta_buf, 0, len);
318 	if (err)
319 		goto done;
320 
321 	m->delta_len = len;
322 	m->delta_compressed_len = compressed_len;
323 done:
324 	free(delta_buf);
325 	return err;
326 }
327 
328 static const struct got_error *
329 encode_delta(struct got_pack_meta *m, struct got_raw_object *o,
330     struct got_delta_instruction *deltas, int ndeltas,
331     off_t base_size, FILE *f)
332 {
333 	const struct got_error *err;
334 	unsigned char buf[16], *bp;
335 	int i, j;
336 	off_t n;
337 	struct got_deflate_buf zb;
338 	struct got_delta_instruction *d;
339 	off_t delta_len = 0, compressed_len = 0;
340 
341 	err = got_deflate_init(&zb, NULL, GOT_DEFLATE_BUFSIZE);
342 	if (err)
343 		return err;
344 
345 	/* base object size */
346 	buf[0] = base_size & GOT_DELTA_SIZE_VAL_MASK;
347 	n = base_size >> GOT_DELTA_SIZE_SHIFT;
348 	for (i = 1; n > 0; i++) {
349 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
350 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
351 		n >>= GOT_DELTA_SIZE_SHIFT;
352 	}
353 
354 	err = got_deflate_append_to_file_mmap(&zb, &compressed_len,
355 	    buf, 0, i, f, NULL);
356 	if (err)
357 		goto done;
358 	delta_len += i;
359 
360 	/* target object size */
361 	buf[0] = o->size & GOT_DELTA_SIZE_VAL_MASK;
362 	n = o->size >> GOT_DELTA_SIZE_SHIFT;
363 	for (i = 1; n > 0; i++) {
364 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
365 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
366 		n >>= GOT_DELTA_SIZE_SHIFT;
367 	}
368 
369 	err = got_deflate_append_to_file_mmap(&zb, &compressed_len,
370 	    buf, 0, i, f, NULL);
371 	if (err)
372 		goto done;
373 	delta_len += i;
374 
375 	for (j = 0; j < ndeltas; j++) {
376 		d = &deltas[j];
377 		if (d->copy) {
378 			n = d->offset;
379 			bp = &buf[1];
380 			buf[0] = GOT_DELTA_BASE_COPY;
381 			for (i = 0; i < 4; i++) {
382 				/* DELTA_COPY_OFF1 ... DELTA_COPY_OFF4 */
383 				buf[0] |= 1 << i;
384 				*bp++ = n & 0xff;
385 				n >>= 8;
386 				if (n == 0)
387 					break;
388 			}
389 			n = d->len;
390 			if (n != GOT_DELTA_COPY_DEFAULT_LEN) {
391 				/* DELTA_COPY_LEN1 ... DELTA_COPY_LEN3 */
392 				for (i = 0; i < 3 && n > 0; i++) {
393 					buf[0] |= 1 << (i + 4);
394 					*bp++ = n & 0xff;
395 					n >>= 8;
396 				}
397 			}
398 			err = got_deflate_append_to_file_mmap(&zb,
399 			    &compressed_len, buf, 0, bp - buf, f, NULL);
400 			if (err)
401 				goto done;
402 			delta_len += (bp - buf);
403 		} else if (o->f == NULL) {
404 			n = 0;
405 			while (n != d->len) {
406 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
407 				err = got_deflate_append_to_file_mmap(&zb,
408 				    &compressed_len, buf, 0, 1, f, NULL);
409 				if (err)
410 					goto done;
411 				delta_len++;
412 				err = got_deflate_append_to_file_mmap(&zb,
413 				    &compressed_len,
414 				    o->data + o->hdrlen + d->offset + n, 0,
415 				    buf[0], f, NULL);
416 				if (err)
417 					goto done;
418 				delta_len += buf[0];
419 				n += buf[0];
420 			}
421 		} else {
422 			char content[128];
423 			size_t r;
424 			if (fseeko(o->f, o->hdrlen + d->offset, SEEK_SET) == -1) {
425 				err = got_error_from_errno("fseeko");
426 				goto done;
427 			}
428 			n = 0;
429 			while (n != d->len) {
430 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
431 				err = got_deflate_append_to_file_mmap(&zb,
432 				    &compressed_len, buf, 0, 1, f, NULL);
433 				if (err)
434 					goto done;
435 				delta_len++;
436 				r = fread(content, 1, buf[0], o->f);
437 				if (r != buf[0]) {
438 					err = got_ferror(o->f, GOT_ERR_IO);
439 					goto done;
440 				}
441 				err = got_deflate_append_to_file_mmap(&zb,
442 				    &compressed_len, content, 0, buf[0], f,
443 				    NULL);
444 				if (err)
445 					goto done;
446 				delta_len += buf[0];
447 				n += buf[0];
448 			}
449 		}
450 	}
451 
452 	err = got_deflate_flush(&zb, f, NULL, &compressed_len);
453 	if (err)
454 		goto done;
455 
456 	/* sanity check */
457 	if (compressed_len != ftello(f) - m->delta_offset) {
458 		err = got_error(GOT_ERR_COMPRESSION);
459 		goto done;
460 	}
461 
462 	m->delta_len = delta_len;
463 	m->delta_compressed_len = compressed_len;
464 done:
465 	got_deflate_end(&zb);
466 	return err;
467 }
468 
469 static const struct got_error *
470 report_progress(got_pack_progress_cb progress_cb, void *progress_arg,
471     struct got_ratelimit *rl, int ncolored, int nfound, int ntrees,
472     off_t packfile_size, int ncommits, int nobj_total, int obj_deltify,
473     int nobj_written)
474 {
475 	const struct got_error *err;
476 	int elapsed;
477 
478 	if (progress_cb == NULL)
479 		return NULL;
480 
481 	err = got_ratelimit_check(&elapsed, rl);
482 	if (err || !elapsed)
483 		return err;
484 
485 	return progress_cb(progress_arg, ncolored, nfound, ntrees,
486 	    packfile_size, ncommits, nobj_total, obj_deltify, nobj_written);
487 }
488 
489 static const struct got_error *
490 add_meta(struct got_pack_meta *m, struct got_pack_metavec *v)
491 {
492 	if (v->nmeta == v->metasz){
493 		size_t newsize = 2 * v->metasz;
494 		struct got_pack_meta **new;
495 		new = reallocarray(v->meta, newsize, sizeof(*new));
496 		if (new == NULL)
497 			return got_error_from_errno("reallocarray");
498 		v->meta = new;
499 		v->metasz = newsize; 
500 	}
501 
502 	v->meta[v->nmeta++] = m;
503 	return NULL;
504 }
505 
506 static const struct got_error *
507 find_pack_for_reuse(struct got_packidx **best_packidx,
508     struct got_repository *repo)
509 {
510 	const struct got_error *err = NULL;
511 	struct got_pathlist_entry *pe;
512 	const char *best_packidx_path = NULL;
513 	int nobj_max = 0;
514 
515 	*best_packidx = NULL;
516 
517 	TAILQ_FOREACH(pe, &repo->packidx_paths, entry) {
518 		const char *path_packidx = pe->path;
519 		struct got_packidx *packidx;
520 		int nobj;
521 
522 		err = got_repo_get_packidx(&packidx, path_packidx, repo);
523 		if (err)
524 			break;
525 
526 		nobj = be32toh(packidx->hdr.fanout_table[0xff]);
527 		if (nobj > nobj_max) {
528 			best_packidx_path = path_packidx;
529 			nobj_max = nobj;
530 		}
531 	}
532 
533 	if (best_packidx_path) {
534 		err = got_repo_get_packidx(best_packidx, best_packidx_path,
535 		    repo);
536 	}
537 
538 	return err;
539 }
540 
541 struct send_id_arg {
542 	struct imsgbuf *ibuf;
543 	struct got_object_id *ids[GOT_IMSG_OBJ_ID_LIST_MAX_NIDS];
544 	size_t nids;
545 };
546 
547 static const struct got_error *
548 send_id(struct got_object_id *id, void *data, void *arg)
549 {
550 	const struct got_error *err = NULL;
551 	struct send_id_arg *a = arg;
552 
553 	a->ids[a->nids++] = id;
554 
555 	if (a->nids >= GOT_IMSG_OBJ_ID_LIST_MAX_NIDS) {
556 		err = got_privsep_send_object_idlist(a->ibuf, a->ids, a->nids);
557 		if (err)
558 			return err;
559 		a->nids = 0;
560 	}
561 
562 	return NULL;
563 }
564 
565 static const struct got_error *
566 send_idset(struct imsgbuf *ibuf, struct got_object_idset *idset)
567 {
568 	const struct got_error *err;
569 	struct send_id_arg sia;
570 
571 	memset(&sia, 0, sizeof(sia));
572 	sia.ibuf = ibuf;
573 	err = got_object_idset_for_each(idset, send_id, &sia);
574 	if (err)
575 		return err;
576 
577 	if (sia.nids > 0) {
578 		err = got_privsep_send_object_idlist(ibuf, sia.ids, sia.nids);
579 		if (err)
580 			return err;
581 	}
582 
583 	return got_privsep_send_object_idlist_done(ibuf);
584 }
585 
586 
587 static const struct got_error *
588 recv_reused_delta(struct got_imsg_reused_delta *delta,
589     struct got_object_idset *idset, struct got_pack_metavec *v)
590 {
591 	struct got_pack_meta *m, *base;
592 
593 	if (delta->delta_offset + delta->delta_size < delta->delta_offset ||
594 	    delta->delta_offset +
595 	    delta->delta_compressed_size < delta->delta_offset)
596 		return got_error(GOT_ERR_BAD_PACKFILE);
597 
598 	m = got_object_idset_get(idset, &delta->id);
599 	if (m == NULL)
600 		return got_error(GOT_ERR_NO_OBJ);
601 
602 	base = got_object_idset_get(idset, &delta->base_id);
603 	if (base == NULL)
604 		return got_error(GOT_ERR_NO_OBJ);
605 
606 	m->delta_len = delta->delta_size;
607 	m->delta_compressed_len = delta->delta_compressed_size;
608 	m->delta_offset = delta->delta_out_offset;
609 	m->prev = base;
610 	m->size = delta->result_size;
611 	m->reused_delta_offset = delta->delta_offset;
612 	m->base_obj_id = got_object_id_dup(&delta->base_id);
613 	if (m->base_obj_id == NULL)
614 		return got_error_from_errno("got_object_id_dup");
615 
616 	return add_meta(m, v);
617 }
618 
619 static const struct got_error *
620 cache_pack_for_packidx(struct got_pack **pack, struct got_packidx *packidx,
621     struct got_repository *repo)
622 {
623 	const struct got_error *err;
624 	char *path_packfile = NULL;
625 
626 	err = got_packidx_get_packfile_path(&path_packfile,
627 	    packidx->path_packidx);
628 	if (err)
629 		return err;
630 
631 	*pack = got_repo_get_cached_pack(repo, path_packfile);
632 	if (*pack == NULL) {
633 		err = got_repo_cache_pack(pack, repo, path_packfile, packidx);
634 		if (err)
635 			goto done;
636 	}
637 	if ((*pack)->privsep_child == NULL) {
638 		err = got_pack_start_privsep_child(*pack, packidx);
639 		if (err)
640 			goto done;
641 	}
642 done:
643 	free(path_packfile);
644 	return err;
645 }
646 
647 static const struct got_error *
648 prepare_delta_reuse(struct got_pack *pack, struct got_packidx *packidx,
649     int delta_outfd, struct got_repository *repo)
650 {
651 	const struct got_error *err = NULL;
652 
653 	if (!pack->child_has_delta_outfd) {
654 		int outfd_child;
655 		outfd_child = dup(delta_outfd);
656 		if (outfd_child == -1) {
657 			err = got_error_from_errno("dup");
658 			goto done;
659 		}
660 		err = got_privsep_send_raw_delta_outfd(
661 		    pack->privsep_child->ibuf, outfd_child);
662 		if (err)
663 			goto done;
664 		pack->child_has_delta_outfd = 1;
665 	}
666 
667 	err = got_privsep_send_delta_reuse_req(pack->privsep_child->ibuf);
668 done:
669 	return err;
670 }
671 
672 
673 static const struct got_error *
674 search_deltas(struct got_pack_metavec *v, struct got_object_idset *idset,
675     int delta_cache_fd, int ncolored, int nfound, int ntrees, int ncommits,
676     struct got_repository *repo,
677     got_pack_progress_cb progress_cb, void *progress_arg,
678     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
679 {
680 	const struct got_error *err = NULL;
681 	struct got_packidx *packidx;
682 	struct got_pack *pack;
683 	struct got_imsg_reused_delta deltas[GOT_IMSG_REUSED_DELTAS_MAX_NDELTAS];
684 	size_t ndeltas, i;
685 
686 	err = find_pack_for_reuse(&packidx, repo);
687 	if (err)
688 		return err;
689 
690 	if (packidx == NULL)
691 		return NULL;
692 
693 	err = cache_pack_for_packidx(&pack, packidx, repo);
694 	if (err)
695 		return err;
696 
697 	err = prepare_delta_reuse(pack, packidx, delta_cache_fd, repo);
698 	if (err)
699 		return err;
700 
701 	err = send_idset(pack->privsep_child->ibuf, idset);
702 	if (err)
703 		return err;
704 
705 	for (;;) {
706 		int done = 0;
707 
708 		if (cancel_cb) {
709 			err = (*cancel_cb)(cancel_arg);
710 			if (err)
711 				break;
712 		}
713 
714 		err = got_privsep_recv_reused_deltas(&done, deltas, &ndeltas,
715 		    pack->privsep_child->ibuf);
716 		if (err || done)
717 			break;
718 
719 		for (i = 0; i < ndeltas; i++) {
720 			struct got_imsg_reused_delta *delta = &deltas[i];
721 			err = recv_reused_delta(delta, idset, v);
722 			if (err)
723 				goto done;
724 		}
725 
726 		err = report_progress(progress_cb, progress_arg, rl,
727 		    ncolored, nfound, ntrees, 0L, ncommits,
728 		    got_object_idset_num_elements(idset), v->nmeta, 0);
729 		if (err)
730 			break;
731 	}
732 done:
733 	return err;
734 }
735 
736 static const struct got_error *
737 pick_deltas(struct got_pack_meta **meta, int nmeta, int ncolored,
738     int nfound, int ntrees, int ncommits, int nreused, FILE *delta_cache,
739     struct got_repository *repo,
740     got_pack_progress_cb progress_cb, void *progress_arg,
741     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
742 {
743 	const struct got_error *err = NULL;
744 	struct got_pack_meta *m = NULL, *base = NULL;
745 	struct got_raw_object *raw = NULL, *base_raw = NULL;
746 	struct got_delta_instruction *deltas = NULL, *best_deltas = NULL;
747 	int i, j, ndeltas, best_ndeltas;
748 	off_t size, best_size;
749 	const int max_base_candidates = 3;
750 	size_t delta_memsize = 0;
751 	const size_t max_delta_memsize = 4 * GOT_DELTA_RESULT_SIZE_CACHED_MAX;
752 	int outfd = -1;
753 	uint32_t delta_seed;
754 
755 	delta_seed = arc4random();
756 
757 	qsort(meta, nmeta, sizeof(struct got_pack_meta *), delta_order_cmp);
758 	for (i = 0; i < nmeta; i++) {
759 		if (cancel_cb) {
760 			err = (*cancel_cb)(cancel_arg);
761 			if (err)
762 				break;
763 		}
764 		err = report_progress(progress_cb, progress_arg, rl,
765 		    ncolored, nfound, ntrees, 0L, ncommits, nreused + nmeta,
766 		    nreused + i, 0);
767 		if (err)
768 			goto done;
769 		m = meta[i];
770 
771 		if (m->obj_type == GOT_OBJ_TYPE_COMMIT ||
772 		    m->obj_type == GOT_OBJ_TYPE_TAG)
773 			continue;
774 
775 		err = got_object_raw_open(&raw, &outfd, repo, &m->id);
776 		if (err)
777 			goto done;
778 		m->size = raw->size;
779 
780 		if (raw->f == NULL) {
781 			err = got_deltify_init_mem(&m->dtab, raw->data,
782 			    raw->hdrlen, raw->size + raw->hdrlen, delta_seed);
783 		} else {
784 			err = got_deltify_init(&m->dtab, raw->f, raw->hdrlen,
785 			    raw->size + raw->hdrlen, delta_seed);
786 		}
787 		if (err)
788 			goto done;
789 
790 		if (i > max_base_candidates) {
791 			struct got_pack_meta *n = NULL;
792 			n = meta[i - (max_base_candidates + 1)];
793 			got_deltify_free(n->dtab);
794 			n->dtab = NULL;
795 		}
796 
797 		best_size = raw->size;
798 		best_ndeltas = 0;
799 		for (j = MAX(0, i - max_base_candidates); j < i; j++) {
800 			if (cancel_cb) {
801 				err = (*cancel_cb)(cancel_arg);
802 				if (err)
803 					goto done;
804 			}
805 			base = meta[j];
806 			/* long chains make unpacking slow, avoid such bases */
807 			if (base->nchain >= 128 ||
808 			    base->obj_type != m->obj_type)
809 				continue;
810 
811 			err = got_object_raw_open(&base_raw, &outfd, repo,
812 			    &base->id);
813 			if (err)
814 				goto done;
815 
816 			if (raw->f == NULL && base_raw->f == NULL) {
817 				err = got_deltify_mem_mem(&deltas, &ndeltas,
818 				    raw->data, raw->hdrlen,
819 				    raw->size + raw->hdrlen, delta_seed,
820 				    base->dtab, base_raw->data,
821 				    base_raw->hdrlen,
822 				    base_raw->size + base_raw->hdrlen);
823 			} else if (raw->f == NULL) {
824 				err = got_deltify_mem_file(&deltas, &ndeltas,
825 				    raw->data, raw->hdrlen,
826 				    raw->size + raw->hdrlen, delta_seed,
827 				    base->dtab, base_raw->f,
828 				    base_raw->hdrlen,
829 				    base_raw->size + base_raw->hdrlen);
830 			} else if (base_raw->f == NULL) {
831 				err = got_deltify_file_mem(&deltas, &ndeltas,
832 				    raw->f, raw->hdrlen,
833 				    raw->size + raw->hdrlen, delta_seed,
834 				    base->dtab, base_raw->data,
835 				    base_raw->hdrlen,
836 				    base_raw->size + base_raw->hdrlen);
837 			} else {
838 				err = got_deltify(&deltas, &ndeltas,
839 				    raw->f, raw->hdrlen,
840 				    raw->size + raw->hdrlen, delta_seed,
841 				    base->dtab, base_raw->f, base_raw->hdrlen,
842 				    base_raw->size + base_raw->hdrlen);
843 			}
844 			got_object_raw_close(base_raw);
845 			base_raw = NULL;
846 			if (err)
847 				goto done;
848 
849 			size = delta_size(deltas, ndeltas);
850 			if (size + 32 < best_size){
851 				/*
852 				 * if we already picked a best delta,
853 				 * replace it.
854 				 */
855 				best_size = size;
856 				free(best_deltas);
857 				best_deltas = deltas;
858 				best_ndeltas = ndeltas;
859 				deltas = NULL;
860 				m->nchain = base->nchain + 1;
861 				m->prev = base;
862 				m->head = base->head;
863 				if (m->head == NULL)
864 					m->head = base;
865 			} else {
866 				free(deltas);
867 				deltas = NULL;
868 				ndeltas = 0;
869 			}
870 		}
871 
872 		if (best_ndeltas > 0) {
873 			if (best_size <= GOT_DELTA_RESULT_SIZE_CACHED_MAX &&
874 			    delta_memsize + best_size <= max_delta_memsize) {
875 				delta_memsize += best_size;
876 				err = encode_delta_in_mem(m, raw, best_deltas,
877 				    best_ndeltas, best_size, m->prev->size);
878 			} else {
879 				m->delta_offset = ftello(delta_cache);
880 				err = encode_delta(m, raw, best_deltas,
881 				    best_ndeltas, m->prev->size, delta_cache);
882 			}
883 			free(best_deltas);
884 			best_deltas = NULL;
885 			best_ndeltas = 0;
886 			if (err)
887 				goto done;
888 		}
889 
890 		got_object_raw_close(raw);
891 		raw = NULL;
892 	}
893 done:
894 	for (i = MAX(0, nmeta - max_base_candidates); i < nmeta; i++) {
895 		got_deltify_free(meta[i]->dtab);
896 		meta[i]->dtab = NULL;
897 	}
898 	if (raw)
899 		got_object_raw_close(raw);
900 	if (base_raw)
901 		got_object_raw_close(base_raw);
902 	if (outfd != -1 && close(outfd) == -1 && err == NULL)
903 		err = got_error_from_errno("close");
904 	free(deltas);
905 	free(best_deltas);
906 	return err;
907 }
908 
909 static const struct got_error *
910 search_packidx(int *found, struct got_object_id *id,
911     struct got_repository *repo)
912 {
913 	const struct got_error *err = NULL;
914 	struct got_packidx *packidx = NULL;
915 	int idx;
916 
917 	*found = 0;
918 
919 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
920 	if (err == NULL)
921 		*found = 1; /* object is already packed */
922 	else if (err->code == GOT_ERR_NO_OBJ)
923 		err = NULL;
924 	return err;
925 }
926 
927 static const struct got_error *
928 add_object(int want_meta, struct got_object_idset *idset,
929     struct got_object_id *id, const char *path, int obj_type,
930     time_t mtime, uint32_t seed, int loose_obj_only,
931     struct got_repository *repo, int *ncolored, int *nfound, int *ntrees,
932     got_pack_progress_cb progress_cb, void *progress_arg,
933     struct got_ratelimit *rl)
934 {
935 	const struct got_error *err;
936 	struct got_pack_meta *m = NULL;
937 
938 	if (loose_obj_only) {
939 		int is_packed;
940 		err = search_packidx(&is_packed, id, repo);
941 		if (err)
942 			return err;
943 		if (is_packed && want_meta)
944 			return NULL;
945 	}
946 
947 	if (want_meta) {
948 		err = alloc_meta(&m, id, path, obj_type, mtime, seed);
949 		if (err)
950 			return err;
951 
952 		(*nfound)++;
953 		err = report_progress(progress_cb, progress_arg, rl,
954 		    *ncolored, *nfound, *ntrees, 0L, 0, 0, 0, 0);
955 		if (err) {
956 			clear_meta(m);
957 			free(m);
958 			return err;
959 		}
960 	}
961 
962 	err = got_object_idset_add(idset, id, m);
963 	if (err) {
964 		clear_meta(m);
965 		free(m);
966 	}
967 	return err;
968 }
969 
970 static const struct got_error *
971 load_tree_entries(struct got_object_id_queue *ids, int want_meta,
972     struct got_object_idset *idset, struct got_object_idset *idset_exclude,
973     struct got_tree_object *tree,
974     const char *dpath, time_t mtime, uint32_t seed, struct got_repository *repo,
975     int loose_obj_only, int *ncolored, int *nfound, int *ntrees,
976     got_pack_progress_cb progress_cb, void *progress_arg,
977     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
978 {
979 	const struct got_error *err;
980 	char *p = NULL;
981 	int i;
982 
983 	(*ntrees)++;
984 	err = report_progress(progress_cb, progress_arg, rl,
985 	    *ncolored, *nfound, *ntrees, 0L, 0, 0, 0, 0);
986 	if (err)
987 		return err;
988 
989 	for (i = 0; i < got_object_tree_get_nentries(tree); i++) {
990 		struct got_tree_entry *e = got_object_tree_get_entry(tree, i);
991 		struct got_object_id *id = got_tree_entry_get_id(e);
992 		mode_t mode = got_tree_entry_get_mode(e);
993 
994 		if (cancel_cb) {
995 			err = (*cancel_cb)(cancel_arg);
996 			if (err)
997 				break;
998 		}
999 
1000 		if (got_object_tree_entry_is_submodule(e) ||
1001 		    got_object_idset_contains(idset, id) ||
1002 		    got_object_idset_contains(idset_exclude, id))
1003 			continue;
1004 
1005 		/*
1006 		 * If got-read-pack is crawling trees for us then
1007 		 * we are only here to collect blob IDs.
1008 		 */
1009 		if (ids == NULL && S_ISDIR(mode))
1010 			continue;
1011 
1012 		if (asprintf(&p, "%s%s%s", dpath,
1013 		    got_path_is_root_dir(dpath) ? "" : "/",
1014 		    got_tree_entry_get_name(e)) == -1) {
1015 			err = got_error_from_errno("asprintf");
1016 			break;
1017 		}
1018 
1019 		if (S_ISDIR(mode)) {
1020 			struct got_object_qid *qid;
1021 			err = got_object_qid_alloc(&qid, id);
1022 			if (err)
1023 				break;
1024 			qid->data = p;
1025 			p = NULL;
1026 			STAILQ_INSERT_TAIL(ids, qid, entry);
1027 		} else if (S_ISREG(mode) || S_ISLNK(mode)) {
1028 			err = add_object(want_meta,
1029 			    want_meta ? idset : idset_exclude, id, p,
1030 			    GOT_OBJ_TYPE_BLOB, mtime, seed, loose_obj_only,
1031 			    repo, ncolored, nfound, ntrees,
1032 			    progress_cb, progress_arg, rl);
1033 			if (err)
1034 				break;
1035 			free(p);
1036 			p = NULL;
1037 		} else {
1038 			free(p);
1039 			p = NULL;
1040 		}
1041 	}
1042 
1043 	free(p);
1044 	return err;
1045 }
1046 
1047 static const struct got_error *
1048 load_tree(int want_meta, struct got_object_idset *idset,
1049     struct got_object_idset *idset_exclude,
1050     struct got_object_id *tree_id, const char *dpath, time_t mtime,
1051     uint32_t seed, struct got_repository *repo, int loose_obj_only,
1052     int *ncolored, int *nfound, int *ntrees,
1053     got_pack_progress_cb progress_cb, void *progress_arg,
1054     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1055 {
1056 	const struct got_error *err = NULL;
1057 	struct got_object_id_queue tree_ids;
1058 	struct got_object_qid *qid;
1059 	struct got_tree_object *tree = NULL;
1060 
1061 	if (got_object_idset_contains(idset, tree_id) ||
1062 	    got_object_idset_contains(idset_exclude, tree_id))
1063 		return NULL;
1064 
1065 	err = got_object_qid_alloc(&qid, tree_id);
1066 	if (err)
1067 		return err;
1068 	qid->data = strdup(dpath);
1069 	if (qid->data == NULL) {
1070 		err = got_error_from_errno("strdup");
1071 		got_object_qid_free(qid);
1072 		return err;
1073 	}
1074 
1075 	STAILQ_INIT(&tree_ids);
1076 	STAILQ_INSERT_TAIL(&tree_ids, qid, entry);
1077 
1078 	while (!STAILQ_EMPTY(&tree_ids)) {
1079 		const char *path;
1080 		if (cancel_cb) {
1081 			err = (*cancel_cb)(cancel_arg);
1082 			if (err)
1083 				break;
1084 		}
1085 
1086 		qid = STAILQ_FIRST(&tree_ids);
1087 		STAILQ_REMOVE_HEAD(&tree_ids, entry);
1088 		path = qid->data;
1089 
1090 		if (got_object_idset_contains(idset, &qid->id) ||
1091 		    got_object_idset_contains(idset_exclude, &qid->id)) {
1092 			free(qid->data);
1093 			got_object_qid_free(qid);
1094 			continue;
1095 		}
1096 
1097 		err = add_object(want_meta, want_meta ? idset : idset_exclude,
1098 		    &qid->id, path, GOT_OBJ_TYPE_TREE,
1099 		    mtime, seed, loose_obj_only, repo,
1100 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
1101 		if (err) {
1102 			free(qid->data);
1103 			got_object_qid_free(qid);
1104 			break;
1105 		}
1106 
1107 		err = got_object_open_as_tree(&tree, repo, &qid->id);
1108 		if (err) {
1109 			free(qid->data);
1110 			got_object_qid_free(qid);
1111 			break;
1112 		}
1113 
1114 		err = load_tree_entries(&tree_ids, want_meta, idset,
1115 		    idset_exclude, tree, path, mtime, seed, repo,
1116 		    loose_obj_only, ncolored, nfound, ntrees,
1117 		    progress_cb, progress_arg, rl,
1118 		    cancel_cb, cancel_arg);
1119 		free(qid->data);
1120 		got_object_qid_free(qid);
1121 		if (err)
1122 			break;
1123 
1124 		got_object_tree_close(tree);
1125 		tree = NULL;
1126 	}
1127 
1128 	STAILQ_FOREACH(qid, &tree_ids, entry)
1129 		free(qid->data);
1130 	got_object_id_queue_free(&tree_ids);
1131 	if (tree)
1132 		got_object_tree_close(tree);
1133 	return err;
1134 }
1135 
1136 static const struct got_error *
1137 load_commit(int want_meta, struct got_object_idset *idset,
1138     struct got_object_idset *idset_exclude,
1139     struct got_object_id *id, struct got_repository *repo, uint32_t seed,
1140     int loose_obj_only, int *ncolored, int *nfound, int *ntrees,
1141     got_pack_progress_cb progress_cb, void *progress_arg,
1142     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1143 {
1144 	const struct got_error *err;
1145 	struct got_commit_object *commit;
1146 
1147 	if (got_object_idset_contains(idset, id) ||
1148 	    got_object_idset_contains(idset_exclude, id))
1149 		return NULL;
1150 
1151 	if (loose_obj_only) {
1152 		int is_packed;
1153 		err = search_packidx(&is_packed, id, repo);
1154 		if (err)
1155 			return err;
1156 		if (is_packed && want_meta)
1157 			return NULL;
1158 	}
1159 
1160 	err = got_object_open_as_commit(&commit, repo, id);
1161 	if (err)
1162 		return err;
1163 
1164 	err = add_object(want_meta, want_meta ? idset : idset_exclude,
1165 	    id, "", GOT_OBJ_TYPE_COMMIT,
1166 	    got_object_commit_get_committer_time(commit), seed,
1167 	    loose_obj_only, repo,
1168 	    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
1169 	if (err)
1170 		goto done;
1171 
1172 	err = load_tree(want_meta, idset, idset_exclude,
1173 	    got_object_commit_get_tree_id(commit),
1174 	    "", got_object_commit_get_committer_time(commit), seed,
1175 	    repo, loose_obj_only, ncolored, nfound, ntrees,
1176 	    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
1177 done:
1178 	got_object_commit_close(commit);
1179 	return err;
1180 }
1181 
1182 static const struct got_error *
1183 load_tag(int want_meta, struct got_object_idset *idset,
1184     struct got_object_idset *idset_exclude,
1185     struct got_object_id *id, struct got_repository *repo, uint32_t seed,
1186     int loose_obj_only, int *ncolored, int *nfound, int *ntrees,
1187     got_pack_progress_cb progress_cb, void *progress_arg,
1188     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1189 {
1190 	const struct got_error *err;
1191 	struct got_tag_object *tag = NULL;
1192 
1193 	if (got_object_idset_contains(idset, id) ||
1194 	    got_object_idset_contains(idset_exclude, id))
1195 		return NULL;
1196 
1197 	if (loose_obj_only) {
1198 		int is_packed;
1199 		err = search_packidx(&is_packed, id, repo);
1200 		if (err)
1201 			return err;
1202 		if (is_packed && want_meta)
1203 			return NULL;
1204 	}
1205 
1206 	err = got_object_open_as_tag(&tag, repo, id);
1207 	if (err)
1208 		return err;
1209 
1210 	err = add_object(want_meta, want_meta ? idset : idset_exclude,
1211 	    id, "", GOT_OBJ_TYPE_TAG,
1212 	    got_object_tag_get_tagger_time(tag), seed, loose_obj_only, repo,
1213 	    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
1214 	if (err)
1215 		goto done;
1216 
1217 	switch (got_object_tag_get_object_type(tag)) {
1218 	case GOT_OBJ_TYPE_COMMIT:
1219 		err = load_commit(want_meta, idset, idset_exclude,
1220 		    got_object_tag_get_object_id(tag), repo, seed,
1221 		    loose_obj_only, ncolored, nfound, ntrees,
1222 		    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
1223 		break;
1224 	case GOT_OBJ_TYPE_TREE:
1225 		err = load_tree(want_meta, idset, idset_exclude,
1226 		    got_object_tag_get_object_id(tag), "",
1227 		    got_object_tag_get_tagger_time(tag), seed, repo,
1228 		    loose_obj_only, ncolored, nfound, ntrees,
1229 		    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
1230 		break;
1231 	default:
1232 		break;
1233 	}
1234 
1235 done:
1236 	got_object_tag_close(tag);
1237 	return err;
1238 }
1239 
1240 enum findtwixt_color {
1241 	COLOR_KEEP = 0,
1242 	COLOR_DROP,
1243 	COLOR_SKIP,
1244 	COLOR_MAX,
1245 };
1246 
1247 static const struct got_error *
1248 paint_commit(struct got_object_qid *qid, intptr_t color)
1249 {
1250 	if (color < 0 || color >= COLOR_MAX)
1251 		return got_error(GOT_ERR_RANGE);
1252 
1253 	qid->data = (void *)color;
1254 	return NULL;
1255 }
1256 
1257 static const struct got_error *
1258 queue_commit_id(struct got_object_id_queue *ids, struct got_object_id *id,
1259     intptr_t color, struct got_repository *repo)
1260 {
1261 	const struct got_error *err;
1262 	struct got_object_qid *qid;
1263 
1264 	err = got_object_qid_alloc(&qid, id);
1265 	if (err)
1266 		return err;
1267 
1268 	STAILQ_INSERT_TAIL(ids, qid, entry);
1269 	return paint_commit(qid, color);
1270 }
1271 
1272 struct append_id_arg {
1273 	struct got_object_id **array;
1274 	int idx;
1275 	struct got_object_idset *drop;
1276 	struct got_object_idset *skip;
1277 };
1278 
1279 static const struct got_error *
1280 append_id(struct got_object_id *id, void *data, void *arg)
1281 {
1282 	struct append_id_arg *a = arg;
1283 
1284 	if (got_object_idset_contains(a->skip, id) ||
1285 	    got_object_idset_contains(a->drop, id))
1286 		return NULL;
1287 
1288 	a->array[++a->idx] = got_object_id_dup(id);
1289 	if (a->array[a->idx] == NULL)
1290 		return got_error_from_errno("got_object_id_dup");
1291 
1292 	return NULL;
1293 }
1294 
1295 static const struct got_error *
1296 queue_commit_or_tag_id(struct got_object_id *id, intptr_t color,
1297     struct got_object_id_queue *ids, struct got_repository *repo)
1298 {
1299 	const struct got_error *err;
1300 	struct got_tag_object *tag = NULL;
1301 	int obj_type;
1302 
1303 	err = got_object_get_type(&obj_type, repo, id);
1304 	if (err)
1305 		return err;
1306 
1307 	if (obj_type == GOT_OBJ_TYPE_TAG) {
1308 		err = got_object_open_as_tag(&tag, repo, id);
1309 		if (err)
1310 			return err;
1311 		obj_type = got_object_tag_get_object_type(tag);
1312 		id = got_object_tag_get_object_id(tag);
1313 	}
1314 
1315 	if (obj_type == GOT_OBJ_TYPE_COMMIT) {
1316 		err = queue_commit_id(ids, id, color, repo);
1317 		if (err)
1318 			goto done;
1319 	}
1320 done:
1321 	if (tag)
1322 		got_object_tag_close(tag);
1323 	return err;
1324 }
1325 
1326 struct recv_painted_commit_arg {
1327 	int *ncolored;
1328 	int *nqueued;
1329 	int *nskip;
1330 	struct got_object_id_queue *ids;
1331 	struct got_object_idset *keep;
1332 	struct got_object_idset *drop;
1333 	struct got_object_idset *skip;
1334 	got_pack_progress_cb progress_cb;
1335 	void *progress_arg;
1336 	struct got_ratelimit *rl;
1337 	got_cancel_cb cancel_cb;
1338 	void *cancel_arg;
1339 };
1340 
1341 static const struct got_error *
1342 recv_painted_commit(void *arg, struct got_object_id *id, intptr_t color)
1343 {
1344 	const struct got_error *err = NULL;
1345 	struct recv_painted_commit_arg *a = arg;
1346 	struct got_object_qid *qid, *tmp;
1347 
1348 	if (a->cancel_cb) {
1349 		err = a->cancel_cb(a->cancel_arg);
1350 		if (err)
1351 			return err;
1352 	}
1353 
1354 	switch (color) {
1355 	case COLOR_KEEP:
1356 		err = got_object_idset_add(a->keep, id, NULL);
1357 		if (err)
1358 			return err;
1359 		(*a->ncolored)++;
1360 		break;
1361 	case COLOR_DROP:
1362 		err = got_object_idset_add(a->drop, id, NULL);
1363 		if (err)
1364 			return err;
1365 		(*a->ncolored)++;
1366 		break;
1367 	case COLOR_SKIP:
1368 		err = got_object_idset_add(a->skip, id, NULL);
1369 		if (err)
1370 			return err;
1371 		break;
1372 	default:
1373 		/* should not happen */
1374 		return got_error_fmt(GOT_ERR_NOT_IMPL,
1375 		    "%s invalid commit color %d", __func__, color);
1376 	}
1377 
1378 	STAILQ_FOREACH_SAFE(qid, a->ids, entry, tmp) {
1379 		if (got_object_id_cmp(&qid->id, id) != 0)
1380 			continue;
1381 		STAILQ_REMOVE(a->ids, qid, got_object_qid, entry);
1382 		color = (intptr_t)qid->data;
1383 		got_object_qid_free(qid);
1384 		(*a->nqueued)--;
1385 		if (color == COLOR_SKIP)
1386 			(*a->nskip)--;
1387 		break;
1388 	}
1389 
1390 	return report_progress(a->progress_cb, a->progress_arg, a->rl,
1391 	    *a->ncolored, 0, 0, 0L, 0, 0, 0, 0);
1392 }
1393 
1394 static const struct got_error *
1395 paint_packed_commits(struct got_pack *pack, struct got_object_id *id,
1396     int idx, intptr_t color, int *ncolored, int *nqueued, int *nskip,
1397     struct got_object_id_queue *ids,
1398     struct got_object_idset *keep, struct got_object_idset *drop,
1399     struct got_object_idset *skip, struct got_repository *repo,
1400     got_pack_progress_cb progress_cb, void *progress_arg,
1401     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1402 {
1403 	const struct got_error *err = NULL;
1404 	struct got_object_id_queue next_ids;
1405 	struct got_object_qid *qid, *tmp;
1406 	struct recv_painted_commit_arg arg;
1407 
1408 	STAILQ_INIT(&next_ids);
1409 
1410 	err = got_privsep_send_painting_request(pack->privsep_child->ibuf,
1411 	    idx, id, color);
1412 	if (err)
1413 		return err;
1414 
1415 	arg.ncolored = ncolored;
1416 	arg.nqueued = nqueued;
1417 	arg.nskip = nskip;
1418 	arg.ids = ids;
1419 	arg.keep = keep;
1420 	arg.drop = drop;
1421 	arg.skip = skip;
1422 	arg.progress_cb = progress_cb;
1423 	arg.progress_arg = progress_arg;
1424 	arg.rl = rl;
1425 	arg.cancel_cb = cancel_cb;
1426 	arg.cancel_arg = cancel_arg;
1427 	err = got_privsep_recv_painted_commits(&next_ids,
1428 	    recv_painted_commit, &arg, pack->privsep_child->ibuf);
1429 	if (err)
1430 		return err;
1431 
1432 	STAILQ_FOREACH_SAFE(qid, &next_ids, entry, tmp) {
1433 		struct got_object_qid *old_id;
1434 		intptr_t qcolor, ocolor;
1435 		STAILQ_FOREACH(old_id, ids, entry) {
1436 			if (got_object_id_cmp(&qid->id, &old_id->id))
1437 				continue;
1438 			qcolor = (intptr_t)qid->data;
1439 			ocolor = (intptr_t)old_id->data;
1440 			STAILQ_REMOVE(&next_ids, qid, got_object_qid, entry);
1441 			got_object_qid_free(qid);
1442 			qid = NULL;
1443 			if (qcolor != ocolor) {
1444 				paint_commit(old_id, qcolor);
1445 				if (ocolor == COLOR_SKIP)
1446 					(*nskip)--;
1447 				else if (qcolor == COLOR_SKIP)
1448 					(*nskip)++;
1449 			}
1450 			break;
1451 		}
1452 	}
1453 	while (!STAILQ_EMPTY(&next_ids)) {
1454 		qid = STAILQ_FIRST(&next_ids);
1455 		STAILQ_REMOVE_HEAD(&next_ids, entry);
1456 		paint_commit(qid, color);
1457 		STAILQ_INSERT_TAIL(ids, qid, entry);
1458 		(*nqueued)++;
1459 		if (color == COLOR_SKIP)
1460 			(*nskip)++;
1461 	}
1462 
1463 	return err;
1464 }
1465 
1466 static const struct got_error *
1467 find_pack_for_commit_painting(struct got_packidx **best_packidx,
1468     struct got_object_id_queue *ids, int nids, struct got_repository *repo)
1469 {
1470 	const struct got_error *err = NULL;
1471 	struct got_pathlist_entry *pe;
1472 	const char *best_packidx_path = NULL;
1473 	int nobj_max = 0;
1474 	int ncommits_max = 0;
1475 
1476 	*best_packidx = NULL;
1477 
1478 	/*
1479 	 * Find the largest pack which contains at least some of the
1480 	 * commits we are interested in.
1481 	 */
1482 	TAILQ_FOREACH(pe, &repo->packidx_paths, entry) {
1483 		const char *path_packidx = pe->path;
1484 		struct got_packidx *packidx;
1485 		int nobj, idx, ncommits = 0;
1486 		struct got_object_qid *qid;
1487 
1488 		err = got_repo_get_packidx(&packidx, path_packidx, repo);
1489 		if (err)
1490 			break;
1491 
1492 		nobj = be32toh(packidx->hdr.fanout_table[0xff]);
1493 		if (nobj <= nobj_max)
1494 			continue;
1495 
1496 		STAILQ_FOREACH(qid, ids, entry) {
1497 			idx = got_packidx_get_object_idx(packidx, &qid->id);
1498 			if (idx != -1)
1499 				ncommits++;
1500 		}
1501 		if (ncommits > ncommits_max) {
1502 			best_packidx_path = path_packidx;
1503 			nobj_max = nobj;
1504 			ncommits_max = ncommits;
1505 		}
1506 	}
1507 
1508 	if (best_packidx_path && err == NULL) {
1509 		err = got_repo_get_packidx(best_packidx, best_packidx_path,
1510 		    repo);
1511 	}
1512 
1513 	return err;
1514 }
1515 
1516 static const struct got_error *
1517 paint_commits(int *ncolored, struct got_object_id_queue *ids, int nids,
1518     struct got_object_idset *keep, struct got_object_idset *drop,
1519     struct got_object_idset *skip, struct got_repository *repo,
1520     got_pack_progress_cb progress_cb, void *progress_arg,
1521     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1522 {
1523 	const struct got_error *err = NULL;
1524 	struct got_commit_object *commit = NULL;
1525 	struct got_packidx *packidx = NULL;
1526 	struct got_pack *pack = NULL;
1527 	const struct got_object_id_queue *parents;
1528 	struct got_object_qid *qid = NULL;
1529 	int nqueued = nids, nskip = 0;
1530 	int idx;
1531 
1532 	while (!STAILQ_EMPTY(ids) && nskip != nqueued) {
1533 		intptr_t color;
1534 
1535 		if (cancel_cb) {
1536 			err = cancel_cb(cancel_arg);
1537 			if (err)
1538 				break;
1539 		}
1540 
1541 		qid = STAILQ_FIRST(ids);
1542 		STAILQ_REMOVE_HEAD(ids, entry);
1543 		nqueued--;
1544 		color = (intptr_t)qid->data;
1545 		if (color == COLOR_SKIP)
1546 			nskip--;
1547 
1548 		if (got_object_idset_contains(skip, &qid->id)) {
1549 			got_object_qid_free(qid);
1550 			qid = NULL;
1551 			continue;
1552 		}
1553 		if (color == COLOR_KEEP &&
1554 		    got_object_idset_contains(keep, &qid->id)) {
1555 			got_object_qid_free(qid);
1556 			qid = NULL;
1557 			continue;
1558 		}
1559 		if (color == COLOR_DROP &&
1560 		    got_object_idset_contains(drop, &qid->id)) {
1561 			got_object_qid_free(qid);
1562 			qid = NULL;
1563 			continue;
1564 		}
1565 
1566 		/* Pinned pack may have moved to different cache slot. */
1567 		pack = got_repo_get_pinned_pack(repo);
1568 
1569 		if (packidx && pack) {
1570 			idx = got_packidx_get_object_idx(packidx, &qid->id);
1571 			if (idx != -1) {
1572 				err = paint_packed_commits(pack, &qid->id,
1573 				    idx, color, ncolored, &nqueued, &nskip,
1574 				    ids, keep, drop, skip, repo,
1575 				    progress_cb, progress_arg, rl,
1576 				    cancel_cb, cancel_arg);
1577 				if (err)
1578 					break;
1579 				got_object_qid_free(qid);
1580 				qid = NULL;
1581 				continue;
1582 			}
1583 		}
1584 
1585 		switch (color) {
1586 		case COLOR_KEEP:
1587 			if (got_object_idset_contains(drop, &qid->id)) {
1588 				err = paint_commit(qid, COLOR_SKIP);
1589 				if (err)
1590 					goto done;
1591 			} else
1592 				(*ncolored)++;
1593 			err = got_object_idset_add(keep, &qid->id, NULL);
1594 			if (err)
1595 				goto done;
1596 			break;
1597 		case COLOR_DROP:
1598 			if (got_object_idset_contains(keep, &qid->id)) {
1599 				err = paint_commit(qid, COLOR_SKIP);
1600 				if (err)
1601 					goto done;
1602 			} else
1603 				(*ncolored)++;
1604 			err = got_object_idset_add(drop, &qid->id, NULL);
1605 			if (err)
1606 				goto done;
1607 			break;
1608 		case COLOR_SKIP:
1609 			if (!got_object_idset_contains(skip, &qid->id)) {
1610 				err = got_object_idset_add(skip, &qid->id,
1611 				    NULL);
1612 				if (err)
1613 					goto done;
1614 			}
1615 			break;
1616 		default:
1617 			/* should not happen */
1618 			err = got_error_fmt(GOT_ERR_NOT_IMPL,
1619 			    "%s invalid commit color %d", __func__, color);
1620 			goto done;
1621 		}
1622 
1623 		err = report_progress(progress_cb, progress_arg, rl,
1624 		    *ncolored, 0, 0, 0L, 0, 0, 0, 0);
1625 		if (err)
1626 			break;
1627 
1628 		err = got_object_open_as_commit(&commit, repo, &qid->id);
1629 		if (err)
1630 			break;
1631 
1632 		parents = got_object_commit_get_parent_ids(commit);
1633 		if (parents) {
1634 			struct got_object_qid *pid;
1635 			color = (intptr_t)qid->data;
1636 			STAILQ_FOREACH(pid, parents, entry) {
1637 				err = queue_commit_id(ids, &pid->id,
1638 				    color, repo);
1639 				if (err)
1640 					break;
1641 				nqueued++;
1642 				if (color == COLOR_SKIP)
1643 					nskip++;
1644 			}
1645 		}
1646 
1647 		if (pack == NULL && (commit->flags & GOT_COMMIT_FLAG_PACKED)) {
1648 			if (packidx == NULL) {
1649 				err = find_pack_for_commit_painting(&packidx,
1650 				    ids, nqueued, repo);
1651 				if (err)
1652 					goto done;
1653 			}
1654 			if (packidx != NULL) {
1655 				err = cache_pack_for_packidx(&pack, packidx,
1656 				    repo);
1657 				if (err)
1658 					goto done;
1659 				err = got_privsep_init_commit_painting(
1660 				    pack->privsep_child->ibuf);
1661 				if (err)
1662 					goto done;
1663 				err = send_idset(pack->privsep_child->ibuf,
1664 				    keep);
1665 				if (err)
1666 					goto done;
1667 				err = send_idset(pack->privsep_child->ibuf, drop);
1668 				if (err)
1669 					goto done;
1670 				err = send_idset(pack->privsep_child->ibuf, skip);
1671 				if (err)
1672 					goto done;
1673 				err = got_repo_pin_pack(repo, packidx, pack);
1674 				if (err)
1675 					goto done;
1676 			}
1677 		}
1678 
1679 		got_object_commit_close(commit);
1680 		commit = NULL;
1681 
1682 		got_object_qid_free(qid);
1683 		qid = NULL;
1684 	}
1685 done:
1686 	if (pack) {
1687 		const struct got_error *pack_err;
1688 		pack_err = got_privsep_send_painting_commits_done(
1689 		    pack->privsep_child->ibuf);
1690 		if (err == NULL)
1691 			err = pack_err;
1692 	}
1693 	if (commit)
1694 		got_object_commit_close(commit);
1695 	got_object_qid_free(qid);
1696 	got_repo_unpin_pack(repo);
1697 	return err;
1698 }
1699 
1700 static const struct got_error *
1701 findtwixt(struct got_object_id ***res, int *nres, int *ncolored,
1702     struct got_object_id **head, int nhead,
1703     struct got_object_id **tail, int ntail,
1704     struct got_repository *repo,
1705     got_pack_progress_cb progress_cb, void *progress_arg,
1706     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1707 {
1708 	const struct got_error *err = NULL;
1709 	struct got_object_id_queue ids;
1710 	struct got_object_idset *keep, *drop, *skip = NULL;
1711 	int i, nkeep;
1712 
1713 	STAILQ_INIT(&ids);
1714 	*res = NULL;
1715 	*nres = 0;
1716 	*ncolored = 0;
1717 
1718 	keep = got_object_idset_alloc();
1719 	if (keep == NULL)
1720 		return got_error_from_errno("got_object_idset_alloc");
1721 
1722 	drop = got_object_idset_alloc();
1723 	if (drop == NULL) {
1724 		err = got_error_from_errno("got_object_idset_alloc");
1725 		goto done;
1726 	}
1727 
1728 	skip = got_object_idset_alloc();
1729 	if (skip == NULL) {
1730 		err = got_error_from_errno("got_object_idset_alloc");
1731 		goto done;
1732 	}
1733 
1734 	for (i = 0; i < nhead; i++) {
1735 		struct got_object_id *id = head[i];
1736 		if (id == NULL)
1737 			continue;
1738 		err = queue_commit_or_tag_id(id, COLOR_KEEP, &ids, repo);
1739 		if (err)
1740 			goto done;
1741 	}		
1742 
1743 	for (i = 0; i < ntail; i++) {
1744 		struct got_object_id *id = tail[i];
1745 		if (id == NULL)
1746 			continue;
1747 		err = queue_commit_or_tag_id(id, COLOR_DROP, &ids, repo);
1748 		if (err)
1749 			goto done;
1750 	}
1751 
1752 	err = paint_commits(ncolored, &ids, nhead + ntail,
1753 	    keep, drop, skip, repo, progress_cb, progress_arg, rl,
1754 	    cancel_cb, cancel_arg);
1755 	if (err)
1756 		goto done;
1757 
1758 	nkeep = got_object_idset_num_elements(keep);
1759 	if (nkeep > 0) {
1760 		struct append_id_arg arg;
1761 		arg.array = calloc(nkeep, sizeof(struct got_object_id *));
1762 		if (arg.array == NULL) {
1763 			err = got_error_from_errno("calloc");
1764 			goto done;
1765 		}
1766 		arg.idx = -1;
1767 		arg.skip = skip;
1768 		arg.drop = drop;
1769 		err = got_object_idset_for_each(keep, append_id, &arg);
1770 		if (err) {
1771 			free(arg.array);
1772 			goto done;
1773 		}
1774 		*res = arg.array;
1775 		*nres = arg.idx + 1;
1776 	}
1777 done:
1778 	got_object_idset_free(keep);
1779 	got_object_idset_free(drop);
1780 	if (skip)
1781 		got_object_idset_free(skip);
1782 	got_object_id_queue_free(&ids);
1783 	return err;
1784 }
1785 
1786 struct load_packed_obj_arg {
1787 	/* output parameters: */
1788 	struct got_object_id *id;
1789 	char *dpath;
1790 	time_t mtime;
1791 
1792 	/* input parameters: */
1793 	uint32_t seed;
1794 	int want_meta;
1795 	struct got_object_idset *idset;
1796 	struct got_object_idset *idset_exclude;
1797 	int loose_obj_only;
1798 	int *ncolored;
1799 	int *nfound;
1800 	int *ntrees;
1801 	got_pack_progress_cb progress_cb;
1802 	void *progress_arg;
1803 	struct got_ratelimit *rl;
1804 	got_cancel_cb cancel_cb;
1805 	void *cancel_arg;
1806 };
1807 
1808 static const struct got_error *
1809 load_packed_commit_id(void *arg, time_t mtime, struct got_object_id *id,
1810     struct got_repository *repo)
1811 {
1812 	struct load_packed_obj_arg *a = arg;
1813 
1814 	if (got_object_idset_contains(a->idset, id) ||
1815 	    got_object_idset_contains(a->idset_exclude, id))
1816 		return NULL;
1817 
1818 	return add_object(a->want_meta,
1819 	    a->want_meta ? a->idset : a->idset_exclude,
1820 	    id, "", GOT_OBJ_TYPE_COMMIT, mtime, a->seed, a->loose_obj_only,
1821 	    repo, a->ncolored, a->nfound, a->ntrees,
1822 	    a->progress_cb, a->progress_arg, a->rl);
1823 }
1824 
1825 static const struct got_error *
1826 load_packed_tree_ids(void *arg, struct got_tree_object *tree, time_t mtime,
1827     struct got_object_id *id, const char *dpath, struct got_repository *repo)
1828 {
1829 	const struct got_error *err;
1830 	struct load_packed_obj_arg *a = arg;
1831 	const char *relpath;
1832 
1833 	/*
1834 	 * When we receive a tree's ID and path but not the tree itself,
1835 	 * this tree object was not found in the pack file. This is the
1836 	 * last time we are being called for this optimized traversal.
1837 	 * Return from here and switch to loading objects the slow way.
1838 	 */
1839 	if (tree == NULL) {
1840 		free(a->id);
1841 		a->id = got_object_id_dup(id);
1842 		if (a->id == NULL) {
1843 			err = got_error_from_errno("got_object_id_dup");
1844 			free(a->dpath);
1845 			a->dpath = NULL;
1846 			return err;
1847 		}
1848 
1849 		free(a->dpath);
1850 		a->dpath = strdup(dpath);
1851 		if (a->dpath == NULL) {
1852 			err = got_error_from_errno("strdup");
1853 			free(a->id);
1854 			a->id = NULL;
1855 			return err;
1856 		}
1857 
1858 		a->mtime = mtime;
1859 		return NULL;
1860 	}
1861 
1862 	if (got_object_idset_contains(a->idset, id) ||
1863 	    got_object_idset_contains(a->idset_exclude, id))
1864 		return NULL;
1865 
1866 	relpath = dpath;
1867 	while (relpath[0] == '/')
1868 		relpath++;
1869 
1870 	err = add_object(a->want_meta,
1871 	    a->want_meta ? a->idset : a->idset_exclude,
1872 	    id, relpath, GOT_OBJ_TYPE_TREE, mtime, a->seed,
1873 	    a->loose_obj_only, repo, a->ncolored, a->nfound, a->ntrees,
1874 	    a->progress_cb, a->progress_arg, a->rl);
1875 	if (err)
1876 		return err;
1877 
1878 	return load_tree_entries(NULL, a->want_meta, a->idset,
1879 	    a->idset_exclude, tree, dpath, mtime, a->seed, repo,
1880 	    a->loose_obj_only, a->ncolored, a->nfound, a->ntrees,
1881 	    a->progress_cb, a->progress_arg, a->rl,
1882 	    a->cancel_cb, a->cancel_arg);
1883 }
1884 
1885 static const struct got_error *
1886 load_packed_object_ids(int *found_all_objects,
1887     struct got_object_id **ours, int nours,
1888     struct got_object_id **theirs, int ntheirs,
1889     int want_meta, uint32_t seed, struct got_object_idset *idset,
1890     struct got_object_idset *idset_exclude, int loose_obj_only,
1891     struct got_repository *repo, struct got_packidx *packidx,
1892     int *ncolored, int *nfound, int *ntrees,
1893     got_pack_progress_cb progress_cb, void *progress_arg,
1894     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1895 {
1896 	const struct got_error *err = NULL;
1897 	struct load_packed_obj_arg lpa;
1898 
1899 	memset(&lpa, 0, sizeof(lpa));
1900 	lpa.seed = seed;
1901 	lpa.want_meta = want_meta;
1902 	lpa.idset = idset;
1903 	lpa.idset_exclude = idset_exclude;
1904 	lpa.loose_obj_only = loose_obj_only;
1905 	lpa.ncolored = ncolored;
1906 	lpa.nfound = nfound;
1907 	lpa.ntrees = ntrees;
1908 	lpa.progress_cb = progress_cb;
1909 	lpa.progress_arg = progress_arg;
1910 	lpa.rl = rl;
1911 	lpa.cancel_cb = cancel_cb;
1912 	lpa.cancel_arg = cancel_arg;
1913 
1914 	/* Attempt to load objects via got-read-pack, as far as possible. */
1915 	err = got_object_enumerate(found_all_objects, load_packed_commit_id,
1916 	   load_packed_tree_ids, &lpa, ours, nours, theirs, ntheirs,
1917 	   packidx, repo);
1918 	if (err)
1919 		return err;
1920 
1921 	if (lpa.id == NULL)
1922 		return NULL;
1923 
1924 	/*
1925 	 * An incomplete tree hierarchy was present in the pack file
1926 	 * and caused loading to be aborted.
1927 	 * Continue loading trees the slow way.
1928 	 */
1929 	err = load_tree(want_meta, idset, idset_exclude,
1930 	    lpa.id, lpa.dpath, lpa.mtime, seed, repo, loose_obj_only,
1931 	    ncolored, nfound, ntrees, progress_cb, progress_arg, rl,
1932 	    cancel_cb, cancel_arg);
1933 	free(lpa.id);
1934 	free(lpa.dpath);
1935 	return err;
1936 }
1937 
1938 static const struct got_error *
1939 find_pack_for_enumeration(struct got_packidx **best_packidx,
1940     struct got_object_id **ids, int nids, struct got_repository *repo)
1941 {
1942 	const struct got_error *err = NULL;
1943 	struct got_pathlist_entry *pe;
1944 	const char *best_packidx_path = NULL;
1945 	int nobj_max = 0;
1946 	int ncommits_max = 0;
1947 
1948 	*best_packidx = NULL;
1949 
1950 	/*
1951 	 * Find the largest pack which contains at least some of the
1952 	 * commits and tags we are interested in.
1953 	 */
1954 	TAILQ_FOREACH(pe, &repo->packidx_paths, entry) {
1955 		const char *path_packidx = pe->path;
1956 		struct got_packidx *packidx;
1957 		int nobj, i, idx, ncommits = 0;
1958 
1959 		err = got_repo_get_packidx(&packidx, path_packidx, repo);
1960 		if (err)
1961 			break;
1962 
1963 		nobj = be32toh(packidx->hdr.fanout_table[0xff]);
1964 		if (nobj <= nobj_max)
1965 			continue;
1966 
1967 		for (i = 0; i < nids; i++) {
1968 			idx = got_packidx_get_object_idx(packidx, ids[i]);
1969 			if (idx != -1)
1970 				ncommits++;
1971 		}
1972 		if (ncommits > ncommits_max) {
1973 			best_packidx_path = path_packidx;
1974 			nobj_max = nobj;
1975 			ncommits_max = ncommits;
1976 		}
1977 	}
1978 
1979 	if (best_packidx_path && err == NULL) {
1980 		err = got_repo_get_packidx(best_packidx, best_packidx_path,
1981 		    repo);
1982 	}
1983 
1984 	return err;
1985 }
1986 
1987 static const struct got_error *
1988 load_object_ids(int *ncolored, int *nfound, int *ntrees,
1989     struct got_object_idset *idset, struct got_object_id **theirs, int ntheirs,
1990     struct got_object_id **ours, int nours, struct got_repository *repo,
1991     uint32_t seed, int loose_obj_only, got_pack_progress_cb progress_cb,
1992     void *progress_arg, struct got_ratelimit *rl, got_cancel_cb cancel_cb,
1993     void *cancel_arg)
1994 {
1995 	const struct got_error *err = NULL;
1996 	struct got_object_id **ids = NULL;
1997 	struct got_packidx *packidx = NULL;
1998 	int i, nobj = 0, obj_type, found_all_objects = 0;
1999 	struct got_object_idset *idset_exclude;
2000 
2001 	idset_exclude = got_object_idset_alloc();
2002 	if (idset_exclude == NULL)
2003 		return got_error_from_errno("got_object_idset_alloc");
2004 
2005 	*ncolored = 0;
2006 	*nfound = 0;
2007 	*ntrees = 0;
2008 
2009 	err = findtwixt(&ids, &nobj, ncolored, ours, nours, theirs, ntheirs,
2010 	    repo, progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
2011 	if (err)
2012 		goto done;
2013 
2014 	err = find_pack_for_enumeration(&packidx, theirs, ntheirs, repo);
2015 	if (err)
2016 		goto done;
2017 	if (packidx) {
2018 		err = load_packed_object_ids(&found_all_objects,
2019 		    theirs, ntheirs, NULL, 0, 0, seed, idset, idset_exclude,
2020 		    loose_obj_only, repo, packidx, ncolored, nfound, ntrees,
2021 		    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
2022 		if (err)
2023 			goto done;
2024 	}
2025 
2026 	for (i = 0; i < ntheirs; i++) {
2027 		struct got_object_id *id = theirs[i];
2028 		if (id == NULL)
2029 			continue;
2030 		err = got_object_get_type(&obj_type, repo, id);
2031 		if (err)
2032 			return err;
2033 		if (obj_type == GOT_OBJ_TYPE_COMMIT) {
2034 			if (!found_all_objects) {
2035 				err = load_commit(0, idset, idset_exclude,
2036 				    id, repo, seed, loose_obj_only,
2037 				    ncolored, nfound, ntrees,
2038 				    progress_cb, progress_arg, rl,
2039 				    cancel_cb, cancel_arg);
2040 				if (err)
2041 					goto done;
2042 			}
2043 		} else if (obj_type == GOT_OBJ_TYPE_TAG) {
2044 			err = load_tag(0, idset, idset_exclude, id, repo,
2045 			    seed, loose_obj_only, ncolored, nfound, ntrees,
2046 			    progress_cb, progress_arg, rl,
2047 			    cancel_cb, cancel_arg);
2048 			if (err)
2049 				goto done;
2050 		}
2051 	}
2052 
2053 	found_all_objects = 0;
2054 	err = find_pack_for_enumeration(&packidx, ids, nobj, repo);
2055 	if (err)
2056 		goto done;
2057 	if (packidx) {
2058 		err = load_packed_object_ids(&found_all_objects, ids,
2059 		    nobj, theirs, ntheirs, 1, seed, idset, idset_exclude,
2060 		    loose_obj_only, repo, packidx, ncolored, nfound, ntrees,
2061 		    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
2062 		if (err)
2063 			goto done;
2064 	}
2065 
2066 	if (!found_all_objects) {
2067 		for (i = 0; i < nobj; i++) {
2068 			err = load_commit(1, idset, idset_exclude, ids[i],
2069 			    repo, seed, loose_obj_only, ncolored, nfound,
2070 			    ntrees, progress_cb, progress_arg, rl,
2071 			    cancel_cb, cancel_arg);
2072 			if (err)
2073 				goto done;
2074 		}
2075 	}
2076 
2077 	for (i = 0; i < nours; i++) {
2078 		struct got_object_id *id = ours[i];
2079 		struct got_pack_meta *m;
2080 		if (id == NULL)
2081 			continue;
2082 		m = got_object_idset_get(idset, id);
2083 		if (m == NULL) {
2084 			err = got_object_get_type(&obj_type, repo, id);
2085 			if (err)
2086 				goto done;
2087 		} else
2088 			obj_type = m->obj_type;
2089 		if (obj_type != GOT_OBJ_TYPE_TAG)
2090 			continue;
2091 		err = load_tag(1, idset, idset_exclude, id, repo,
2092 		    seed, loose_obj_only, ncolored, nfound, ntrees,
2093 		    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
2094 		if (err)
2095 			goto done;
2096 	}
2097 done:
2098 	for (i = 0; i < nobj; i++) {
2099 		free(ids[i]);
2100 	}
2101 	free(ids);
2102 	got_object_idset_free(idset_exclude);
2103 	return err;
2104 }
2105 
2106 static const struct got_error *
2107 hwrite(FILE *f, const void *buf, off_t len, SHA1_CTX *ctx)
2108 {
2109 	size_t n;
2110 
2111 	SHA1Update(ctx, buf, len);
2112 	n = fwrite(buf, 1, len, f);
2113 	if (n != len)
2114 		return got_ferror(f, GOT_ERR_IO);
2115 	return NULL;
2116 }
2117 
2118 static const struct got_error *
2119 hcopy(FILE *fsrc, FILE *fdst, off_t len, SHA1_CTX *ctx)
2120 {
2121 	unsigned char buf[65536];
2122 	off_t remain = len;
2123 	size_t n;
2124 
2125 	while (remain > 0) {
2126 		size_t copylen = MIN(sizeof(buf), remain);
2127 		n = fread(buf, 1, copylen, fsrc);
2128 		if (n != copylen)
2129 			return got_ferror(fsrc, GOT_ERR_IO);
2130 		SHA1Update(ctx, buf, copylen);
2131 		n = fwrite(buf, 1, copylen, fdst);
2132 		if (n != copylen)
2133 			return got_ferror(fdst, GOT_ERR_IO);
2134 		remain -= copylen;
2135 	}
2136 
2137 	return NULL;
2138 }
2139 
2140 static const struct got_error *
2141 hcopy_mmap(uint8_t *src, off_t src_offset, size_t src_size,
2142     FILE *fdst, off_t len, SHA1_CTX *ctx)
2143 {
2144 	size_t n;
2145 
2146 	if (src_offset + len > src_size)
2147 		return got_error(GOT_ERR_RANGE);
2148 
2149 	SHA1Update(ctx, src + src_offset, len);
2150 	n = fwrite(src + src_offset, 1, len, fdst);
2151 	if (n != len)
2152 		return got_ferror(fdst, GOT_ERR_IO);
2153 
2154 	return NULL;
2155 }
2156 
2157 static void
2158 putbe32(char *b, uint32_t n)
2159 {
2160 	b[0] = n >> 24;
2161 	b[1] = n >> 16;
2162 	b[2] = n >> 8;
2163 	b[3] = n >> 0;
2164 }
2165 
2166 static int
2167 write_order_cmp(const void *pa, const void *pb)
2168 {
2169 	struct got_pack_meta *a, *b, *ahd, *bhd;
2170 
2171 	a = *(struct got_pack_meta **)pa;
2172 	b = *(struct got_pack_meta **)pb;
2173 	ahd = (a->head == NULL) ? a : a->head;
2174 	bhd = (b->head == NULL) ? b : b->head;
2175 	if (bhd->mtime < ahd->mtime)
2176 		return -1;
2177 	if (bhd->mtime > ahd->mtime)
2178 		return 1;
2179 	if (bhd < ahd)
2180 		return -1;
2181 	if (bhd > ahd)
2182 		return 1;
2183 	if (a->nchain != b->nchain)
2184 		return a->nchain - b->nchain;
2185 	if (a->mtime < b->mtime)
2186 		return -1;
2187 	if (a->mtime > b->mtime)
2188 		return 1;
2189 	return got_object_id_cmp(&a->id, &b->id);
2190 }
2191 
2192 static int
2193 reuse_write_order_cmp(const void *pa, const void *pb)
2194 {
2195 	struct got_pack_meta *a, *b;
2196 
2197 	a = *(struct got_pack_meta **)pa;
2198 	b = *(struct got_pack_meta **)pb;
2199 
2200 	if (a->reused_delta_offset < b->reused_delta_offset)
2201 		return -1;
2202 	if (a->reused_delta_offset > b->reused_delta_offset)
2203 		return 1;
2204 	return 0;
2205 }
2206 
2207 static const struct got_error *
2208 packhdr(int *hdrlen, char *hdr, size_t bufsize, int obj_type, size_t len)
2209 {
2210 	size_t i;
2211 
2212 	*hdrlen = 0;
2213 
2214 	hdr[0] = obj_type << 4;
2215 	hdr[0] |= len & 0xf;
2216 	len >>= 4;
2217 	for (i = 1; len != 0; i++){
2218 		if (i >= bufsize)
2219 			return got_error(GOT_ERR_NO_SPACE);
2220 		hdr[i - 1] |= GOT_DELTA_SIZE_MORE;
2221 		hdr[i] = len & GOT_DELTA_SIZE_VAL_MASK;
2222 		len >>= GOT_DELTA_SIZE_SHIFT;
2223 	}
2224 
2225 	*hdrlen = i;
2226 	return NULL;
2227 }
2228 
2229 static int
2230 packoff(char *hdr, off_t off)
2231 {
2232 	int i, j;
2233 	char rbuf[8];
2234 
2235 	rbuf[0] = off & GOT_DELTA_SIZE_VAL_MASK;
2236 	for (i = 1; (off >>= GOT_DELTA_SIZE_SHIFT) != 0; i++) {
2237 		rbuf[i] = (--off & GOT_DELTA_SIZE_VAL_MASK) |
2238 		    GOT_DELTA_SIZE_MORE;
2239 	}
2240 
2241 	j = 0;
2242 	while (i > 0)
2243 		hdr[j++] = rbuf[--i];
2244 	return j;
2245 }
2246 
2247 static const struct got_error *
2248 deltahdr(off_t *packfile_size, SHA1_CTX *ctx, FILE *packfile,
2249     struct got_pack_meta *m)
2250 {
2251 	const struct got_error *err;
2252 	char buf[32];
2253 	int nh;
2254 
2255 	if (m->prev->off != 0) {
2256 		err = packhdr(&nh, buf, sizeof(buf),
2257 		    GOT_OBJ_TYPE_OFFSET_DELTA, m->delta_len);
2258 		if (err)
2259 			return err;
2260 		nh += packoff(buf + nh, m->off - m->prev->off);
2261 		err = hwrite(packfile, buf, nh, ctx);
2262 		if (err)
2263 			return err;
2264 		*packfile_size += nh;
2265 	} else {
2266 		err = packhdr(&nh, buf, sizeof(buf),
2267 		    GOT_OBJ_TYPE_REF_DELTA, m->delta_len);
2268 		if (err)
2269 			return err;
2270 		err = hwrite(packfile, buf, nh, ctx);
2271 		if (err)
2272 			return err;
2273 		*packfile_size += nh;
2274 		err = hwrite(packfile, m->prev->id.sha1,
2275 		    sizeof(m->prev->id.sha1), ctx);
2276 		if (err)
2277 			return err;
2278 		*packfile_size += sizeof(m->prev->id.sha1);
2279 	}
2280 
2281 	return NULL;
2282 }
2283 
2284 static const struct got_error *
2285 write_packed_object(off_t *packfile_size, FILE *packfile,
2286     FILE *delta_cache, uint8_t *delta_cache_map, size_t delta_cache_size,
2287     struct got_pack_meta *m, int *outfd, SHA1_CTX *ctx,
2288     struct got_repository *repo)
2289 {
2290 	const struct got_error *err = NULL;
2291 	struct got_deflate_checksum csum;
2292 	char buf[32];
2293 	int nh;
2294 	struct got_raw_object *raw = NULL;
2295 	off_t outlen;
2296 
2297 	csum.output_sha1 = ctx;
2298 	csum.output_crc = NULL;
2299 
2300 	m->off = ftello(packfile);
2301 	if (m->delta_len == 0) {
2302 		err = got_object_raw_open(&raw, outfd, repo, &m->id);
2303 		if (err)
2304 			goto done;
2305 		err = packhdr(&nh, buf, sizeof(buf),
2306 		    m->obj_type, raw->size);
2307 		if (err)
2308 			goto done;
2309 		err = hwrite(packfile, buf, nh, ctx);
2310 		if (err)
2311 			goto done;
2312 		*packfile_size += nh;
2313 		if (raw->f == NULL) {
2314 			err = got_deflate_to_file_mmap(&outlen,
2315 			    raw->data + raw->hdrlen, 0, raw->size,
2316 			    packfile, &csum);
2317 			if (err)
2318 				goto done;
2319 		} else {
2320 			if (fseeko(raw->f, raw->hdrlen, SEEK_SET)
2321 			    == -1) {
2322 				err = got_error_from_errno("fseeko");
2323 				goto done;
2324 			}
2325 			err = got_deflate_to_file(&outlen, raw->f,
2326 			    raw->size, packfile, &csum);
2327 			if (err)
2328 				goto done;
2329 		}
2330 		*packfile_size += outlen;
2331 		got_object_raw_close(raw);
2332 		raw = NULL;
2333 	} else if (m->delta_buf) {
2334 		err = deltahdr(packfile_size, ctx, packfile, m);
2335 		if (err)
2336 			goto done;
2337 		err = hwrite(packfile, m->delta_buf,
2338 		    m->delta_compressed_len, ctx);
2339 		if (err)
2340 			goto done;
2341 		*packfile_size += m->delta_compressed_len;
2342 		free(m->delta_buf);
2343 		m->delta_buf = NULL;
2344 	} else if (delta_cache_map) {
2345 		err = deltahdr(packfile_size, ctx, packfile, m);
2346 		if (err)
2347 			goto done;
2348 		err = hcopy_mmap(delta_cache_map, m->delta_offset,
2349 		    delta_cache_size, packfile, m->delta_compressed_len,
2350 		    ctx);
2351 		if (err)
2352 			goto done;
2353 		*packfile_size += m->delta_compressed_len;
2354 	} else {
2355 		if (fseeko(delta_cache, m->delta_offset, SEEK_SET)
2356 		    == -1) {
2357 			err = got_error_from_errno("fseeko");
2358 			goto done;
2359 		}
2360 		err = deltahdr(packfile_size, ctx, packfile, m);
2361 		if (err)
2362 			goto done;
2363 		err = hcopy(delta_cache, packfile,
2364 		    m->delta_compressed_len, ctx);
2365 		if (err)
2366 			goto done;
2367 		*packfile_size += m->delta_compressed_len;
2368 	}
2369 done:
2370 	if (raw)
2371 		got_object_raw_close(raw);
2372 	return err;
2373 }
2374 
2375 static const struct got_error *
2376 genpack(uint8_t *pack_sha1, FILE *packfile, FILE *delta_cache,
2377     struct got_pack_meta **deltify, int ndeltify,
2378     struct got_pack_meta **reuse, int nreuse,
2379     int ncolored, int nfound, int ntrees, int nours,
2380     struct got_repository *repo,
2381     got_pack_progress_cb progress_cb, void *progress_arg,
2382     struct got_ratelimit *rl,
2383     got_cancel_cb cancel_cb, void *cancel_arg)
2384 {
2385 	const struct got_error *err = NULL;
2386 	int i;
2387 	SHA1_CTX ctx;
2388 	struct got_pack_meta *m;
2389 	char buf[32];
2390 	size_t n;
2391 	off_t packfile_size = 0;
2392 	int outfd = -1;
2393 	int delta_cache_fd = -1;
2394 	uint8_t *delta_cache_map = NULL;
2395 	size_t delta_cache_size = 0;
2396 
2397 	SHA1Init(&ctx);
2398 
2399 #ifndef GOT_PACK_NO_MMAP
2400 	delta_cache_fd = dup(fileno(delta_cache));
2401 	if (delta_cache_fd != -1) {
2402 		struct stat sb;
2403 		if (fstat(delta_cache_fd, &sb) == -1) {
2404 			err = got_error_from_errno("fstat");
2405 			goto done;
2406 		}
2407 		if (sb.st_size > 0 && sb.st_size <= SIZE_MAX) {
2408 			delta_cache_map = mmap(NULL, sb.st_size,
2409 			    PROT_READ, MAP_PRIVATE, delta_cache_fd, 0);
2410 			if (delta_cache_map == MAP_FAILED) {
2411 				if (errno != ENOMEM) {
2412 					err = got_error_from_errno("mmap");
2413 					goto done;
2414 				}
2415 				delta_cache_map = NULL; /* fallback on stdio */
2416 			} else
2417 				delta_cache_size = (size_t)sb.st_size;
2418 		}
2419 	}
2420 #endif
2421 	err = hwrite(packfile, "PACK", 4, &ctx);
2422 	if (err)
2423 		goto done;
2424 	putbe32(buf, GOT_PACKFILE_VERSION);
2425 	err = hwrite(packfile, buf, 4, &ctx);
2426 	if (err)
2427 		goto done;
2428 	putbe32(buf, ndeltify + nreuse);
2429 	err = hwrite(packfile, buf, 4, &ctx);
2430 	if (err)
2431 		goto done;
2432 
2433 	qsort(deltify, ndeltify, sizeof(struct got_pack_meta *),
2434 	    write_order_cmp);
2435 	for (i = 0; i < ndeltify; i++) {
2436 		err = report_progress(progress_cb, progress_arg, rl,
2437 		    ncolored, nfound, ntrees, packfile_size, nours,
2438 		    ndeltify + nreuse, ndeltify + nreuse, i);
2439 		if (err)
2440 			goto done;
2441 		m = deltify[i];
2442 		err = write_packed_object(&packfile_size, packfile,
2443 		    delta_cache, delta_cache_map, delta_cache_size,
2444 		    m, &outfd, &ctx, repo);
2445 		if (err)
2446 			goto done;
2447 	}
2448 
2449 	qsort(reuse, nreuse, sizeof(struct got_pack_meta *),
2450 	    reuse_write_order_cmp);
2451 	for (i = 0; i < nreuse; i++) {
2452 		err = report_progress(progress_cb, progress_arg, rl,
2453 		    ncolored, nfound, ntrees, packfile_size, nours,
2454 		    ndeltify + nreuse, ndeltify + nreuse, ndeltify + i);
2455 		if (err)
2456 			goto done;
2457 		m = reuse[i];
2458 		err = write_packed_object(&packfile_size, packfile,
2459 		    delta_cache, delta_cache_map, delta_cache_size,
2460 		    m, &outfd, &ctx, repo);
2461 		if (err)
2462 			goto done;
2463 	}
2464 
2465 	SHA1Final(pack_sha1, &ctx);
2466 	n = fwrite(pack_sha1, 1, SHA1_DIGEST_LENGTH, packfile);
2467 	if (n != SHA1_DIGEST_LENGTH)
2468 		err = got_ferror(packfile, GOT_ERR_IO);
2469 	packfile_size += SHA1_DIGEST_LENGTH;
2470 	packfile_size += sizeof(struct got_packfile_hdr);
2471 	if (progress_cb) {
2472 		err = progress_cb(progress_arg, ncolored, nfound, ntrees,
2473 		    packfile_size, nours, ndeltify + nreuse,
2474 		    ndeltify + nreuse, ndeltify + nreuse);
2475 		if (err)
2476 			goto done;
2477 	}
2478 done:
2479 	if (outfd != -1 && close(outfd) == -1 && err == NULL)
2480 		err = got_error_from_errno("close");
2481 	if (delta_cache_map && munmap(delta_cache_map, delta_cache_size) == -1)
2482 		err = got_error_from_errno("munmap");
2483 	if (delta_cache_fd != -1 && close(delta_cache_fd) == -1 && err == NULL)
2484 		err = got_error_from_errno("close");
2485 	return err;
2486 }
2487 
2488 static const struct got_error *
2489 add_meta_idset_cb(struct got_object_id *id, void *data, void *arg)
2490 {
2491 	struct got_pack_meta *m = data;
2492 	struct got_pack_metavec *v = arg;
2493 
2494 	if (m->reused_delta_offset != 0)
2495 		return NULL;
2496 
2497 	return add_meta(m, v);
2498 }
2499 
2500 const struct got_error *
2501 got_pack_create(uint8_t *packsha1, FILE *packfile,
2502     struct got_object_id **theirs, int ntheirs,
2503     struct got_object_id **ours, int nours,
2504     struct got_repository *repo, int loose_obj_only, int allow_empty,
2505     got_pack_progress_cb progress_cb, void *progress_arg,
2506     got_cancel_cb cancel_cb, void *cancel_arg)
2507 {
2508 	const struct got_error *err;
2509 	int delta_cache_fd = -1;
2510 	FILE *delta_cache = NULL;
2511 	struct got_object_idset *idset;
2512 	struct got_ratelimit rl;
2513 	struct got_pack_metavec deltify, reuse;
2514 	int ncolored = 0, nfound = 0, ntrees = 0;
2515 	size_t ndeltify;
2516 	uint32_t seed;
2517 
2518 	seed = arc4random();
2519 
2520 	memset(&deltify, 0, sizeof(deltify));
2521 	memset(&reuse, 0, sizeof(reuse));
2522 
2523 	got_ratelimit_init(&rl, 0, 500);
2524 
2525 	idset = got_object_idset_alloc();
2526 	if (idset == NULL)
2527 		return got_error_from_errno("got_object_idset_alloc");
2528 
2529 	err = load_object_ids(&ncolored, &nfound, &ntrees, idset, theirs,
2530 	    ntheirs, ours, nours, repo, seed, loose_obj_only,
2531 	    progress_cb, progress_arg, &rl, cancel_cb, cancel_arg);
2532 	if (err)
2533 		goto done;
2534 
2535 	if (progress_cb) {
2536 		err = progress_cb(progress_arg, ncolored, nfound, ntrees,
2537 		    0L, nours, got_object_idset_num_elements(idset), 0, 0);
2538 		if (err)
2539 			goto done;
2540 	}
2541 
2542 	if (got_object_idset_num_elements(idset) == 0 && !allow_empty) {
2543 		err = got_error(GOT_ERR_CANNOT_PACK);
2544 		goto done;
2545 	}
2546 
2547 	delta_cache_fd = got_opentempfd();
2548 	if (delta_cache_fd == -1) {
2549 		err = got_error_from_errno("got_opentemp");
2550 		goto done;
2551 	}
2552 
2553 	reuse.metasz = 64;
2554 	reuse.meta = calloc(reuse.metasz,
2555 	    sizeof(struct got_pack_meta *));
2556 	if (reuse.meta == NULL) {
2557 		err = got_error_from_errno("calloc");
2558 		goto done;
2559 	}
2560 
2561 	err = search_deltas(&reuse, idset, delta_cache_fd, ncolored, nfound,
2562 	    ntrees, nours, repo, progress_cb, progress_arg, &rl,
2563 	    cancel_cb, cancel_arg);
2564 	if (err)
2565 		goto done;
2566 
2567 	delta_cache = fdopen(delta_cache_fd, "a+");
2568 	if (delta_cache == NULL) {
2569 		err = got_error_from_errno("fdopen");
2570 		goto done;
2571 	}
2572 	delta_cache_fd = -1;
2573 
2574 	if (fseeko(delta_cache, 0L, SEEK_END) == -1) {
2575 		err = got_error_from_errno("fseeko");
2576 		goto done;
2577 	}
2578 
2579 	ndeltify = got_object_idset_num_elements(idset) - reuse.nmeta;
2580 	if (ndeltify > 0) {
2581 		deltify.meta = calloc(ndeltify, sizeof(struct got_pack_meta *));
2582 		if (deltify.meta == NULL) {
2583 			err = got_error_from_errno("calloc");
2584 			goto done;
2585 		}
2586 		deltify.metasz = ndeltify;
2587 
2588 		err = got_object_idset_for_each(idset, add_meta_idset_cb,
2589 		    &deltify);
2590 		if (err)
2591 			goto done;
2592 		if (deltify.nmeta > 0) {
2593 			err = pick_deltas(deltify.meta, deltify.nmeta,
2594 			    ncolored, nfound, ntrees, nours, reuse.nmeta,
2595 			    delta_cache, repo, progress_cb, progress_arg, &rl,
2596 			    cancel_cb, cancel_arg);
2597 			if (err)
2598 				goto done;
2599 		}
2600 	}
2601 
2602 	if (fflush(delta_cache) == EOF) {
2603 		err = got_error_from_errno("fflush");
2604 		goto done;
2605 	}
2606 	err = genpack(packsha1, packfile, delta_cache, deltify.meta,
2607 	    deltify.nmeta, reuse.meta, reuse.nmeta, ncolored, nfound, ntrees,
2608 	    nours, repo, progress_cb, progress_arg, &rl,
2609 	    cancel_cb, cancel_arg);
2610 	if (err)
2611 		goto done;
2612 done:
2613 	free_nmeta(deltify.meta, deltify.nmeta);
2614 	free_nmeta(reuse.meta, reuse.nmeta);
2615 	got_object_idset_free(idset);
2616 	if (delta_cache_fd != -1 && close(delta_cache_fd) == -1 && err == NULL)
2617 		err = got_error_from_errno("close");
2618 	if (delta_cache && fclose(delta_cache) == EOF && err == NULL)
2619 		err = got_error_from_errno("fclose");
2620 	return err;
2621 }