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Date:: Sun May 1 11:50:34 2022 UTC
Message:: avoid subtraction of values larger than int in qsort(3) comparison callbacks tweak + ok tb@
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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/uio.h>
20 #include <sys/stat.h>
21 #include <sys/time.h>
22 
23 #include <stdint.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <time.h>
28 #include <unistd.h>
29 #include <limits.h>
30 #include <zlib.h>
31 
32 #if defined(__FreeBSD__)
33 #include <unistd.h>
34 #endif
35 
36 #include "got_error.h"
37 #include "got_cancel.h"
38 #include "got_object.h"
39 #include "got_path.h"
40 #include "got_reference.h"
41 #include "got_repository_admin.h"
42 #include "got_opentemp.h"
43 
44 #include "got_lib_deltify.h"
45 #include "got_lib_delta.h"
46 #include "got_lib_object.h"
47 #include "got_lib_object_idset.h"
48 #include "got_lib_object_cache.h"
49 #include "got_lib_deflate.h"
50 #include "got_lib_pack.h"
51 #include "got_lib_privsep.h"
52 #include "got_lib_repository.h"
53 #include "got_lib_ratelimit.h"
54 
55 #ifndef MIN
56 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
57 #endif
58 
59 #ifndef MAX
60 #define	MAX(_a,_b) ((_a) > (_b) ? (_a) : (_b))
61 #endif
62 
63 #ifndef nitems
64 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
65 #endif
66 
67 struct got_pack_meta {
68 	struct got_object_id id;
69 	char	*path;
70 	int	obj_type;
71 	off_t	size;
72 	time_t	mtime;
73 
74 	/* The best delta we picked */
75 	struct got_pack_meta *head;
76 	struct got_pack_meta *prev;
77 	unsigned char *delta_buf; /* if not encoded in delta cache file */
78 	off_t	delta_offset;	/* offset in delta cache file */
79 	off_t	delta_len;	/* encoded delta length */
80 	int	nchain;
81 
82 	int	have_reused_delta;
83 	off_t   reused_delta_offset; /* offset of delta in reused pack file */
84 	struct got_object_id *base_obj_id;
85 
86 	/* Only used for delta window */
87 	struct got_delta_table *dtab;
88 
89 	/* Only used for writing offset deltas */
90 	off_t	off;
91 };
92 
93 struct got_pack_metavec {
94 	struct got_pack_meta **meta;
95 	int nmeta;
96 	int metasz;
97 };
98 
99 static const struct got_error *
100 alloc_meta(struct got_pack_meta **new, struct got_object_id *id,
101     const char *path, int obj_type, time_t mtime)
102 {
103 	const struct got_error *err = NULL;
104 	struct got_pack_meta *m;
105 
106 	*new = NULL;
107 
108 	m = calloc(1, sizeof(*m));
109 	if (m == NULL)
110 		return got_error_from_errno("calloc");
111 
112 	memcpy(&m->id, id, sizeof(m->id));
113 
114 	m->path = strdup(path);
115 	if (m->path == NULL) {
116 		err = got_error_from_errno("strdup");
117 		free(m);
118 		return err;
119 	}
120 
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 	free(meta->path);
133 	meta->path = NULL;
134 	free(meta->delta_buf);
135 	meta->delta_buf = NULL;
136 	free(meta->base_obj_id);
137 	meta->base_obj_id = NULL;
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 	int cmp;
155 
156 	a = *(struct got_pack_meta **)pa;
157 	b = *(struct got_pack_meta **)pb;
158 
159 	if (a->obj_type != b->obj_type)
160 		return a->obj_type - b->obj_type;
161 	cmp = strcmp(a->path, b->path);
162 	if (cmp != 0)
163 		return cmp;
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;
212 	off_t n;
213 	struct got_delta_instruction *d;
214 
215 	m->delta_buf = malloc(delta_size);
216 	if (m->delta_buf == NULL)
217 		return got_error_from_errno("calloc");
218 
219 	/* base object size */
220 	buf[0] = base_size & GOT_DELTA_SIZE_VAL_MASK;
221 	n = base_size >> GOT_DELTA_SIZE_SHIFT;
222 	for (i = 1; n > 0; i++) {
223 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
224 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
225 		n >>= GOT_DELTA_SIZE_SHIFT;
226 	}
227 	err = append(&m->delta_buf, &len, &delta_size, buf, i);
228 	if (err)
229 		return err;
230 
231 	/* target object size */
232 	buf[0] = o->size & GOT_DELTA_SIZE_VAL_MASK;
233 	n = o->size >> GOT_DELTA_SIZE_SHIFT;
234 	for (i = 1; n > 0; i++) {
235 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
236 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
237 		n >>= GOT_DELTA_SIZE_SHIFT;
238 	}
239 	err = append(&m->delta_buf, &len, &delta_size, buf, i);
240 	if (err)
241 		return err;
242 
243 	for (j = 0; j < ndeltas; j++) {
244 		d = &deltas[j];
245 		if (d->copy) {
246 			n = d->offset;
247 			bp = &buf[1];
248 			buf[0] = GOT_DELTA_BASE_COPY;
249 			for (i = 0; i < 4; i++) {
250 				/* DELTA_COPY_OFF1 ... DELTA_COPY_OFF4 */
251 				buf[0] |= 1 << i;
252 				*bp++ = n & 0xff;
253 				n >>= 8;
254 				if (n == 0)
255 					break;
256 			}
257 
258 			n = d->len;
259 			if (n != GOT_DELTA_COPY_DEFAULT_LEN) {
260 				/* DELTA_COPY_LEN1 ... DELTA_COPY_LEN3 */
261 				for (i = 0; i < 3 && n > 0; i++) {
262 					buf[0] |= 1 << (i + 4);
263 					*bp++ = n & 0xff;
264 					n >>= 8;
265 				}
266 			}
267 			err = append(&m->delta_buf, &len, &delta_size,
268 			    buf, bp - buf);
269 			if (err)
270 				return err;
271 		} else if (o->f == NULL) {
272 			n = 0;
273 			while (n != d->len) {
274 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
275 				err = append(&m->delta_buf, &len, &delta_size,
276 				    buf, 1);
277 				if (err)
278 					return err;
279 				err = append(&m->delta_buf, &len, &delta_size,
280 				    o->data + o->hdrlen + d->offset + n,
281 				    buf[0]);
282 				if (err)
283 					return err;
284 				n += buf[0];
285 			}
286 		} else {
287 			char content[128];
288 			size_t r;
289 			if (fseeko(o->f, o->hdrlen + d->offset, SEEK_SET) == -1)
290 				return got_error_from_errno("fseeko");
291 			n = 0;
292 			while (n != d->len) {
293 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
294 				err = append(&m->delta_buf, &len, &delta_size,
295 				    buf, 1);
296 				if (err)
297 					return err;
298 				r = fread(content, 1, buf[0], o->f);
299 				if (r != buf[0])
300 					return got_ferror(o->f, GOT_ERR_IO);
301 				err = append(&m->delta_buf, &len, &delta_size,
302 				    content, buf[0]);
303 				if (err)
304 					return err;
305 				n += buf[0];
306 			}
307 		}
308 	}
309 
310 	m->delta_len = len;
311 	return NULL;
312 }
313 
314 static const struct got_error *
315 encode_delta(struct got_pack_meta *m, struct got_raw_object *o,
316     struct got_delta_instruction *deltas, int ndeltas,
317     off_t base_size, FILE *f)
318 {
319 	unsigned char buf[16], *bp;
320 	int i, j;
321 	off_t n;
322 	size_t w;
323 	struct got_delta_instruction *d;
324 
325 	/* base object size */
326 	buf[0] = base_size & GOT_DELTA_SIZE_VAL_MASK;
327 	n = base_size >> GOT_DELTA_SIZE_SHIFT;
328 	for (i = 1; n > 0; i++) {
329 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
330 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
331 		n >>= GOT_DELTA_SIZE_SHIFT;
332 	}
333 	w = fwrite(buf, 1, i, f);
334 	if (w != i)
335 		return got_ferror(f, GOT_ERR_IO);
336 
337 	/* target object size */
338 	buf[0] = o->size & GOT_DELTA_SIZE_VAL_MASK;
339 	n = o->size >> GOT_DELTA_SIZE_SHIFT;
340 	for (i = 1; n > 0; i++) {
341 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
342 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
343 		n >>= GOT_DELTA_SIZE_SHIFT;
344 	}
345 	w = fwrite(buf, 1, i, f);
346 	if (w != i)
347 		return got_ferror(f, GOT_ERR_IO);
348 
349 	for (j = 0; j < ndeltas; j++) {
350 		d = &deltas[j];
351 		if (d->copy) {
352 			n = d->offset;
353 			bp = &buf[1];
354 			buf[0] = GOT_DELTA_BASE_COPY;
355 			for (i = 0; i < 4; i++) {
356 				/* DELTA_COPY_OFF1 ... DELTA_COPY_OFF4 */
357 				buf[0] |= 1 << i;
358 				*bp++ = n & 0xff;
359 				n >>= 8;
360 				if (n == 0)
361 					break;
362 			}
363 
364 			n = d->len;
365 			if (n != GOT_DELTA_COPY_DEFAULT_LEN) {
366 				/* DELTA_COPY_LEN1 ... DELTA_COPY_LEN3 */
367 				for (i = 0; i < 3 && n > 0; i++) {
368 					buf[0] |= 1 << (i + 4);
369 					*bp++ = n & 0xff;
370 					n >>= 8;
371 				}
372 			}
373 			w = fwrite(buf, 1, bp - buf, f);
374 			if (w != bp - buf)
375 				return got_ferror(f, GOT_ERR_IO);
376 		} else if (o->f == NULL) {
377 			n = 0;
378 			while (n != d->len) {
379 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
380 				w = fwrite(buf, 1, 1, f);
381 				if (w != 1)
382 					return got_ferror(f, GOT_ERR_IO);
383 				w = fwrite(o->data + o->hdrlen + d->offset + n,
384 				    1, buf[0], f);
385 				if (w != buf[0])
386 					return got_ferror(f, GOT_ERR_IO);
387 				n += buf[0];
388 			}
389 		} else {
390 			char content[128];
391 			size_t r;
392 			if (fseeko(o->f, o->hdrlen + d->offset, SEEK_SET) == -1)
393 				return got_error_from_errno("fseeko");
394 			n = 0;
395 			while (n != d->len) {
396 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
397 				w = fwrite(buf, 1, 1, f);
398 				if (w != 1)
399 					return got_ferror(f, GOT_ERR_IO);
400 				r = fread(content, 1, buf[0], o->f);
401 				if (r != buf[0])
402 					return got_ferror(o->f, GOT_ERR_IO);
403 				w = fwrite(content, 1, buf[0], f);
404 				if (w != buf[0])
405 					return got_ferror(f, GOT_ERR_IO);
406 				n += buf[0];
407 			}
408 		}
409 	}
410 
411 	m->delta_len = ftello(f) - m->delta_offset;
412 	return NULL;
413 }
414 
415 static const struct got_error *
416 report_progress(got_pack_progress_cb progress_cb, void *progress_arg,
417     struct got_ratelimit *rl, int ncolored, int nfound, int ntrees,
418     off_t packfile_size, int ncommits, int nobj_total, int obj_deltify,
419     int nobj_written)
420 {
421 	const struct got_error *err;
422 	int elapsed;
423 
424 	if (progress_cb == NULL)
425 		return NULL;
426 
427 	err = got_ratelimit_check(&elapsed, rl);
428 	if (err || !elapsed)
429 		return err;
430 
431 	return progress_cb(progress_arg, ncolored, nfound, ntrees,
432 	    packfile_size, ncommits, nobj_total, obj_deltify, nobj_written);
433 }
434 
435 static const struct got_error *
436 add_meta(struct got_pack_meta *m, struct got_pack_metavec *v)
437 {
438 	if (v->nmeta == v->metasz){
439 		size_t newsize = 2 * v->metasz;
440 		struct got_pack_meta **new;
441 		new = reallocarray(v->meta, newsize, sizeof(*new));
442 		if (new == NULL)
443 			return got_error_from_errno("reallocarray");
444 		v->meta = new;
445 		v->metasz = newsize; 
446 	}
447 
448 	v->meta[v->nmeta++] = m;
449 	return NULL;
450 }
451 
452 static const struct got_error *
453 reuse_delta(int idx, struct got_pack_meta *m, struct got_pack_metavec *v,
454     struct got_object_idset *idset, struct got_pack *pack,
455     struct got_packidx *packidx, int delta_cache_fd,
456     struct got_repository *repo)
457 {
458 	const struct got_error *err = NULL;
459 	struct got_pack_meta *base = NULL;
460 	struct got_object_id *base_obj_id = NULL;
461 	off_t delta_len = 0, delta_offset = 0, delta_cache_offset = 0;
462 	uint64_t base_size, result_size;
463 
464 	if (m->have_reused_delta)
465 		return NULL;
466 
467 	err = got_object_read_raw_delta(&base_size, &result_size, &delta_len,
468 	    &delta_offset, &delta_cache_offset, &base_obj_id, delta_cache_fd,
469 	    packidx, idx, &m->id, repo);
470 	if (err)
471 		return err;
472 
473 	if (delta_offset + delta_len < delta_offset)
474 		return got_error(GOT_ERR_BAD_PACKFILE);
475 
476 	base = got_object_idset_get(idset, base_obj_id);
477 	if (base == NULL)
478 		goto done;
479 
480 	m->delta_len = delta_len;
481 	m->delta_offset = delta_cache_offset;
482 	m->prev = base;
483 	m->size = result_size;
484 	m->have_reused_delta = 1;
485 	m->reused_delta_offset = delta_offset;
486 	m->base_obj_id = base_obj_id;
487 	base_obj_id = NULL;
488 	err = add_meta(m, v);
489 done:
490 	free(base_obj_id);
491 	return err;
492 }
493 
494 static const struct got_error *
495 find_pack_for_reuse(struct got_packidx **best_packidx,
496     struct got_repository *repo)
497 {
498 	const struct got_error *err = NULL;
499 	struct got_pathlist_entry *pe;
500 	const char *best_packidx_path = NULL;
501 	int nobj_max = 0;
502 
503 	*best_packidx = NULL;
504 
505 	TAILQ_FOREACH(pe, &repo->packidx_paths, entry) {
506 		const char *path_packidx = pe->path;
507 		struct got_packidx *packidx;
508 		int nobj;
509 
510 		err = got_repo_get_packidx(&packidx, path_packidx, repo);
511 		if (err)
512 			break;
513 
514 		nobj = be32toh(packidx->hdr.fanout_table[0xff]);
515 		if (nobj > nobj_max) {
516 			best_packidx_path = path_packidx;
517 			nobj_max = nobj;
518 		}
519 	}
520 
521 	if (best_packidx_path) {
522 		err = got_repo_get_packidx(best_packidx, best_packidx_path,
523 		    repo);
524 	}
525 
526 	return err;
527 }
528 
529 struct search_deltas_arg {
530 	struct got_packidx *packidx;
531 	struct got_pack *pack;
532 	struct got_object_idset *idset;
533 	struct got_pack_metavec *v;
534 	int delta_cache_fd;
535 	struct got_repository *repo;
536 	got_pack_progress_cb progress_cb;
537 	void *progress_arg;
538 	struct got_ratelimit *rl;
539 	got_cancel_cb cancel_cb;
540 	void *cancel_arg;
541 	int ncolored;
542 	int nfound;
543 	int ntrees;
544 	int ncommits;
545 };
546 
547 static const struct got_error *
548 search_delta_for_object(struct got_object_id *id, void *data, void *arg)
549 {
550 	const struct got_error *err;
551 	struct got_pack_meta *m = data;
552 	struct search_deltas_arg *a = arg;
553 	int obj_idx;
554 	struct got_object *obj = NULL;
555 
556 	if (a->cancel_cb) {
557 		err = (*a->cancel_cb)(a->cancel_arg);
558 		if (err)
559 			return err;
560 	}
561 
562 	if (!got_repo_check_packidx_bloom_filter(a->repo,
563 	    a->packidx->path_packidx, id))
564 		return NULL;
565 
566 	obj_idx = got_packidx_get_object_idx(a->packidx, id);
567 	if (obj_idx == -1)
568 		return NULL;
569 
570 	/* TODO:
571 	 * Opening and closing an object just to check its flags
572 	 * is a bit expensive. We could have an imsg which requests
573 	 * plain type/size information for an object without doing
574 	 * work such as traversing the object's entire delta chain
575 	 * to find the base object type, and other such info which
576 	 * we don't really need here.
577 	 */
578 	err = got_object_open_from_packfile(&obj, &m->id, a->pack,
579 	    a->packidx, obj_idx, a->repo);
580 	if (err)
581 		return err;
582 
583 	if (obj->flags & GOT_OBJ_FLAG_DELTIFIED) {
584 		reuse_delta(obj_idx, m, a->v, a->idset, a->pack, a->packidx,
585 		    a->delta_cache_fd, a->repo);
586 		if (err)
587 			goto done;
588 		err = report_progress(a->progress_cb, a->progress_arg, a->rl,
589 		    a->ncolored, a->nfound, a->ntrees, 0L, a->ncommits,
590 		    got_object_idset_num_elements(a->idset), a->v->nmeta, 0);
591 	}
592 done:
593 	got_object_close(obj);
594 	return err;
595 }
596 
597 static const struct got_error *
598 search_deltas(struct got_pack_metavec *v, struct got_object_idset *idset,
599     int delta_cache_fd, int ncolored, int nfound, int ntrees, int ncommits,
600     struct got_repository *repo,
601     got_pack_progress_cb progress_cb, void *progress_arg,
602     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
603 {
604 	const struct got_error *err = NULL;
605 	char *path_packfile = NULL;
606 	struct got_packidx *packidx;
607 	struct got_pack *pack;
608 	struct search_deltas_arg sda;
609 
610 	err = find_pack_for_reuse(&packidx, repo);
611 	if (err)
612 		return err;
613 
614 	if (packidx == NULL)
615 		return NULL;
616 
617 	err = got_packidx_get_packfile_path(&path_packfile,
618 	    packidx->path_packidx);
619 	if (err)
620 		return err;
621 
622 	pack = got_repo_get_cached_pack(repo, path_packfile);
623 	if (pack == NULL) {
624 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
625 		if (err)
626 			goto done;
627 	}
628 
629 	sda.packidx = packidx;
630 	sda.pack = pack;
631 	sda.idset = idset;
632 	sda.v = v;
633 	sda.delta_cache_fd = delta_cache_fd;
634 	sda.repo = repo;
635 	sda.progress_cb = progress_cb;
636 	sda.progress_arg = progress_arg;
637 	sda.rl = rl;
638 	sda.cancel_cb = cancel_cb;
639 	sda.cancel_arg = cancel_arg;
640 	sda.ncolored = ncolored;
641 	sda.nfound = nfound;
642 	sda.ntrees = ntrees;
643 	sda.ncommits = ncommits;
644 	err = got_object_idset_for_each(idset, search_delta_for_object, &sda);
645 done:
646 	free(path_packfile);
647 	return err;
648 }
649 
650 static const struct got_error *
651 pick_deltas(struct got_pack_meta **meta, int nmeta, int ncolored,
652     int nfound, int ntrees, int ncommits, int nreused, FILE *delta_cache,
653     struct got_repository *repo,
654     got_pack_progress_cb progress_cb, void *progress_arg,
655     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
656 {
657 	const struct got_error *err = NULL;
658 	struct got_pack_meta *m = NULL, *base = NULL;
659 	struct got_raw_object *raw = NULL, *base_raw = NULL;
660 	struct got_delta_instruction *deltas = NULL, *best_deltas = NULL;
661 	int i, j, ndeltas, best_ndeltas;
662 	off_t size, best_size;
663 	const int max_base_candidates = 3;
664 	size_t delta_memsize = 0;
665 	const size_t max_delta_memsize = 25 * GOT_DELTA_RESULT_SIZE_CACHED_MAX;
666 	int outfd = -1;
667 
668 	qsort(meta, nmeta, sizeof(struct got_pack_meta *), delta_order_cmp);
669 	for (i = 0; i < nmeta; i++) {
670 		if (cancel_cb) {
671 			err = (*cancel_cb)(cancel_arg);
672 			if (err)
673 				break;
674 		}
675 		err = report_progress(progress_cb, progress_arg, rl,
676 		    ncolored, nfound, ntrees, 0L, ncommits, nreused + nmeta,
677 		    nreused + i, 0);
678 		if (err)
679 			goto done;
680 		m = meta[i];
681 
682 		if (m->obj_type == GOT_OBJ_TYPE_COMMIT ||
683 		    m->obj_type == GOT_OBJ_TYPE_TAG)
684 			continue;
685 
686 		err = got_object_raw_open(&raw, &outfd, repo, &m->id);
687 		if (err)
688 			goto done;
689 		m->size = raw->size;
690 
691 		if (raw->f == NULL) {
692 			err = got_deltify_init_mem(&m->dtab, raw->data,
693 			    raw->hdrlen, raw->size + raw->hdrlen);
694 		} else {
695 			err = got_deltify_init(&m->dtab, raw->f, raw->hdrlen,
696 			    raw->size + raw->hdrlen);
697 		}
698 		if (err)
699 			goto done;
700 
701 		if (i > max_base_candidates) {
702 			struct got_pack_meta *n = NULL;
703 			n = meta[i - (max_base_candidates + 1)];
704 			got_deltify_free(n->dtab);
705 			n->dtab = NULL;
706 		}
707 
708 		best_size = raw->size;
709 		best_ndeltas = 0;
710 		for (j = MAX(0, i - max_base_candidates); j < i; j++) {
711 			if (cancel_cb) {
712 				err = (*cancel_cb)(cancel_arg);
713 				if (err)
714 					goto done;
715 			}
716 			base = meta[j];
717 			/* long chains make unpacking slow, avoid such bases */
718 			if (base->nchain >= 128 ||
719 			    base->obj_type != m->obj_type)
720 				continue;
721 
722 			err = got_object_raw_open(&base_raw, &outfd, repo,
723 			    &base->id);
724 			if (err)
725 				goto done;
726 
727 			if (raw->f == NULL && base_raw->f == NULL) {
728 				err = got_deltify_mem_mem(&deltas, &ndeltas,
729 				    raw->data, raw->hdrlen,
730 				    raw->size + raw->hdrlen,
731 				    base->dtab, base_raw->data,
732 				    base_raw->hdrlen,
733 				    base_raw->size + base_raw->hdrlen);
734 			} else if (raw->f == NULL) {
735 				err = got_deltify_mem_file(&deltas, &ndeltas,
736 				    raw->data, raw->hdrlen,
737 				    raw->size + raw->hdrlen,
738 				    base->dtab, base_raw->f,
739 				    base_raw->hdrlen,
740 				    base_raw->size + base_raw->hdrlen);
741 			} else if (base_raw->f == NULL) {
742 				err = got_deltify_file_mem(&deltas, &ndeltas,
743 				    raw->f, raw->hdrlen,
744 				    raw->size + raw->hdrlen,
745 				    base->dtab, base_raw->data,
746 				    base_raw->hdrlen,
747 				    base_raw->size + base_raw->hdrlen);
748 			} else {
749 				err = got_deltify(&deltas, &ndeltas,
750 				    raw->f, raw->hdrlen,
751 				    raw->size + raw->hdrlen,
752 				    base->dtab, base_raw->f, base_raw->hdrlen,
753 				    base_raw->size + base_raw->hdrlen);
754 			}
755 			got_object_raw_close(base_raw);
756 			base_raw = NULL;
757 			if (err)
758 				goto done;
759 
760 			size = delta_size(deltas, ndeltas);
761 			if (size + 32 < best_size){
762 				/*
763 				 * if we already picked a best delta,
764 				 * replace it.
765 				 */
766 				best_size = size;
767 				free(best_deltas);
768 				best_deltas = deltas;
769 				best_ndeltas = ndeltas;
770 				deltas = NULL;
771 				m->nchain = base->nchain + 1;
772 				m->prev = base;
773 				m->head = base->head;
774 				if (m->head == NULL)
775 					m->head = base;
776 			} else {
777 				free(deltas);
778 				deltas = NULL;
779 				ndeltas = 0;
780 			}
781 		}
782 
783 		if (best_ndeltas > 0) {
784 			if (best_size <= GOT_DELTA_RESULT_SIZE_CACHED_MAX &&
785 			    delta_memsize + best_size <= max_delta_memsize) {
786 				delta_memsize += best_size;
787 				err = encode_delta_in_mem(m, raw, best_deltas,
788 				    best_ndeltas, best_size, m->prev->size);
789 			} else {
790 				m->delta_offset = ftello(delta_cache);
791 				/*
792 				 * TODO:
793 				 * Storing compressed delta data in the delta
794 				 * cache file would probably be more efficient
795 				 * than writing uncompressed delta data here
796 				 * and compressing it while writing the pack
797 				 * file. This would also allow for reusing
798 				 * deltas in their compressed form.
799 				 */
800 				err = encode_delta(m, raw, best_deltas,
801 				    best_ndeltas, m->prev->size, delta_cache);
802 			}
803 			free(best_deltas);
804 			best_deltas = NULL;
805 			best_ndeltas = 0;
806 			if (err)
807 				goto done;
808 		}
809 
810 		got_object_raw_close(raw);
811 		raw = NULL;
812 	}
813 done:
814 	for (i = MAX(0, nmeta - max_base_candidates); i < nmeta; i++) {
815 		got_deltify_free(meta[i]->dtab);
816 		meta[i]->dtab = NULL;
817 	}
818 	if (raw)
819 		got_object_raw_close(raw);
820 	if (base_raw)
821 		got_object_raw_close(base_raw);
822 	if (outfd != -1 && close(outfd) == -1 && err == NULL)
823 		err = got_error_from_errno("close");
824 	free(deltas);
825 	free(best_deltas);
826 	return err;
827 }
828 
829 static const struct got_error *
830 search_packidx(int *found, struct got_object_id *id,
831     struct got_repository *repo)
832 {
833 	const struct got_error *err = NULL;
834 	struct got_packidx *packidx = NULL;
835 	int idx;
836 
837 	*found = 0;
838 
839 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
840 	if (err == NULL)
841 		*found = 1; /* object is already packed */
842 	else if (err->code == GOT_ERR_NO_OBJ)
843 		err = NULL;
844 	return err;
845 }
846 
847 static const struct got_error *
848 add_object(int want_meta, struct got_object_idset *idset,
849     struct got_object_id *id, const char *path, int obj_type,
850     time_t mtime, int loose_obj_only, struct got_repository *repo,
851     int *ncolored, int *nfound, int *ntrees,
852     got_pack_progress_cb progress_cb, void *progress_arg,
853     struct got_ratelimit *rl)
854 {
855 	const struct got_error *err;
856 	struct got_pack_meta *m = NULL;
857 
858 	if (loose_obj_only) {
859 		int is_packed;
860 		err = search_packidx(&is_packed, id, repo);
861 		if (err)
862 			return err;
863 		if (is_packed && want_meta)
864 			return NULL;
865 	}
866 
867 	if (want_meta) {
868 		err = alloc_meta(&m, id, path, obj_type, mtime);
869 		if (err)
870 			return err;
871 
872 		(*nfound)++;
873 		err = report_progress(progress_cb, progress_arg, rl,
874 		    *ncolored, *nfound, *ntrees, 0L, 0, 0, 0, 0);
875 		if (err) {
876 			clear_meta(m);
877 			free(m);
878 			return err;
879 		}
880 	}
881 
882 	err = got_object_idset_add(idset, id, m);
883 	if (err) {
884 		clear_meta(m);
885 		free(m);
886 	}
887 	return err;
888 }
889 
890 static const struct got_error *
891 load_tree_entries(struct got_object_id_queue *ids, int want_meta,
892     struct got_object_idset *idset, struct got_object_id *tree_id,
893     const char *dpath, time_t mtime, struct got_repository *repo,
894     int loose_obj_only, int *ncolored, int *nfound, int *ntrees,
895     got_pack_progress_cb progress_cb, void *progress_arg,
896     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
897 {
898 	const struct got_error *err;
899 	struct got_tree_object *tree;
900 	char *p = NULL;
901 	int i;
902 
903 	err = got_object_open_as_tree(&tree, repo, tree_id);
904 	if (err)
905 		return err;
906 
907 	(*ntrees)++;
908 	err = report_progress(progress_cb, progress_arg, rl,
909 	    *ncolored, *nfound, *ntrees, 0L, 0, 0, 0, 0);
910 	if (err)
911 		return err;
912 
913 	for (i = 0; i < got_object_tree_get_nentries(tree); i++) {
914 		struct got_tree_entry *e = got_object_tree_get_entry(tree, i);
915 		struct got_object_id *id = got_tree_entry_get_id(e);
916 		mode_t mode = got_tree_entry_get_mode(e);
917 
918 		if (cancel_cb) {
919 			err = (*cancel_cb)(cancel_arg);
920 			if (err)
921 				break;
922 		}
923 
924 		if (got_object_tree_entry_is_submodule(e) ||
925 		    got_object_idset_contains(idset, id))
926 			continue;
927 		
928 		if (asprintf(&p, "%s%s%s", dpath, dpath[0] != '\0' ? "/" : "",
929 		    got_tree_entry_get_name(e)) == -1) {
930 			err = got_error_from_errno("asprintf");
931 			break;
932 		}
933 
934 		if (S_ISDIR(mode)) {
935 			struct got_object_qid *qid;
936 			err = got_object_qid_alloc(&qid, id);
937 			if (err)
938 				break;
939 			STAILQ_INSERT_TAIL(ids, qid, entry);
940 		} else if (S_ISREG(mode) || S_ISLNK(mode)) {
941 			err = add_object(want_meta, idset, id, p,
942 			    GOT_OBJ_TYPE_BLOB, mtime, loose_obj_only, repo,
943 			    ncolored, nfound, ntrees,
944 			    progress_cb, progress_arg, rl);
945 			if (err)
946 				break;
947 		}
948 		free(p);
949 		p = NULL;
950 	}
951 
952 	got_object_tree_close(tree);
953 	free(p);
954 	return err;
955 }
956 
957 static const struct got_error *
958 load_tree(int want_meta, struct got_object_idset *idset,
959     struct got_object_id *tree_id, const char *dpath, time_t mtime,
960     struct got_repository *repo, int loose_obj_only,
961     int *ncolored, int *nfound, int *ntrees,
962     got_pack_progress_cb progress_cb, void *progress_arg,
963     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
964 {
965 	const struct got_error *err = NULL;
966 	struct got_object_id_queue tree_ids;
967 	struct got_object_qid *qid;
968 
969 	if (got_object_idset_contains(idset, tree_id))
970 		return NULL;
971 
972 	err = got_object_qid_alloc(&qid, tree_id);
973 	if (err)
974 		return err;
975 
976 	STAILQ_INIT(&tree_ids);
977 	STAILQ_INSERT_TAIL(&tree_ids, qid, entry);
978 
979 	while (!STAILQ_EMPTY(&tree_ids)) {
980 		if (cancel_cb) {
981 			err = (*cancel_cb)(cancel_arg);
982 			if (err)
983 				break;
984 		}
985 
986 		qid = STAILQ_FIRST(&tree_ids);
987 		STAILQ_REMOVE_HEAD(&tree_ids, entry);
988 
989 		if (got_object_idset_contains(idset, &qid->id)) {
990 			got_object_qid_free(qid);
991 			continue;
992 		}
993 
994 		err = add_object(want_meta, idset, &qid->id, dpath,
995 		    GOT_OBJ_TYPE_TREE, mtime, loose_obj_only, repo,
996 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
997 		if (err) {
998 			got_object_qid_free(qid);
999 			break;
1000 		}
1001 
1002 		err = load_tree_entries(&tree_ids, want_meta, idset, &qid->id,
1003 		    dpath, mtime, repo, loose_obj_only, ncolored, nfound,
1004 		    ntrees, progress_cb, progress_arg, rl,
1005 		    cancel_cb, cancel_arg);
1006 		got_object_qid_free(qid);
1007 		if (err)
1008 			break;
1009 	}
1010 
1011 	got_object_id_queue_free(&tree_ids);
1012 	return err;
1013 }
1014 
1015 static const struct got_error *
1016 load_commit(int want_meta, struct got_object_idset *idset,
1017     struct got_object_id *id, struct got_repository *repo, int loose_obj_only,
1018     int *ncolored, int *nfound, int *ntrees,
1019     got_pack_progress_cb progress_cb, void *progress_arg,
1020     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1021 {
1022 	const struct got_error *err;
1023 	struct got_commit_object *commit;
1024 
1025 	if (got_object_idset_contains(idset, id))
1026 		return NULL;
1027 
1028 	if (loose_obj_only) {
1029 		int is_packed;
1030 		err = search_packidx(&is_packed, id, repo);
1031 		if (err)
1032 			return err;
1033 		if (is_packed && want_meta)
1034 			return NULL;
1035 	}
1036 
1037 	err = got_object_open_as_commit(&commit, repo, id);
1038 	if (err)
1039 		return err;
1040 
1041 	err = add_object(want_meta, idset, id, "", GOT_OBJ_TYPE_COMMIT,
1042 	    got_object_commit_get_committer_time(commit),
1043 	    loose_obj_only, repo,
1044 	    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
1045 	if (err)
1046 		goto done;
1047 
1048 	err = load_tree(want_meta, idset, got_object_commit_get_tree_id(commit),
1049 	    "", got_object_commit_get_committer_time(commit),
1050 	    repo, loose_obj_only, ncolored, nfound, ntrees,
1051 	    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
1052 done:
1053 	got_object_commit_close(commit);
1054 	return err;
1055 }
1056 
1057 static const struct got_error *
1058 load_tag(int want_meta, struct got_object_idset *idset,
1059     struct got_object_id *id, struct got_repository *repo, int loose_obj_only,
1060     int *ncolored, int *nfound, int *ntrees,
1061     got_pack_progress_cb progress_cb, void *progress_arg,
1062     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1063 {
1064 	const struct got_error *err;
1065 	struct got_tag_object *tag = NULL;
1066 
1067 	if (got_object_idset_contains(idset, id))
1068 		return NULL;
1069 
1070 	if (loose_obj_only) {
1071 		int is_packed;
1072 		err = search_packidx(&is_packed, id, repo);
1073 		if (err)
1074 			return err;
1075 		if (is_packed && want_meta)
1076 			return NULL;
1077 	}
1078 
1079 	err = got_object_open_as_tag(&tag, repo, id);
1080 	if (err)
1081 		return err;
1082 
1083 	err = add_object(want_meta, idset, id, "", GOT_OBJ_TYPE_TAG,
1084 	    got_object_tag_get_tagger_time(tag), loose_obj_only, repo,
1085 	    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
1086 	if (err)
1087 		goto done;
1088 
1089 	switch (got_object_tag_get_object_type(tag)) {
1090 	case GOT_OBJ_TYPE_COMMIT:
1091 		err = load_commit(want_meta, idset,
1092 		    got_object_tag_get_object_id(tag), repo, loose_obj_only,
1093 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl,
1094 		    cancel_cb, cancel_arg);
1095 		break;
1096 	case GOT_OBJ_TYPE_TREE:
1097 		err = load_tree(want_meta, idset,
1098 		    got_object_tag_get_object_id(tag), "",
1099 		    got_object_tag_get_tagger_time(tag), repo, loose_obj_only,
1100 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl,
1101 		    cancel_cb, cancel_arg);
1102 		break;
1103 	default:
1104 		break;
1105 	}
1106 
1107 done:
1108 	got_object_tag_close(tag);
1109 	return err;
1110 }
1111 
1112 enum findtwixt_color {
1113 	COLOR_KEEP = 0,
1114 	COLOR_DROP,
1115 	COLOR_BLANK,
1116 	COLOR_SKIP,
1117 };
1118 
1119 static const int findtwixt_colors[] = {
1120 	COLOR_KEEP,
1121 	COLOR_DROP,
1122 	COLOR_BLANK,
1123 	COLOR_SKIP,
1124 };
1125 
1126 static const struct got_error *
1127 paint_commit(struct got_object_qid *qid, int color)
1128 {
1129 	if (color < 0 || color >= nitems(findtwixt_colors))
1130 		return got_error(GOT_ERR_RANGE);
1131 
1132 	qid->data = (void *)&findtwixt_colors[color];
1133 	return NULL;
1134 }
1135 
1136 static const struct got_error *
1137 queue_commit_id(struct got_object_id_queue *ids, struct got_object_id *id,
1138     int color, struct got_repository *repo)
1139 {
1140 	const struct got_error *err;
1141 	struct got_object_qid *qid;
1142 
1143 	err = got_object_qid_alloc(&qid, id);
1144 	if (err)
1145 		return err;
1146 
1147 	STAILQ_INSERT_TAIL(ids, qid, entry);
1148 	return paint_commit(qid, color);
1149 }
1150 
1151 struct append_id_arg {
1152 	struct got_object_id **array;
1153 	int idx;
1154 	struct got_object_idset *drop;
1155 	struct got_object_idset *skip;
1156 };
1157 
1158 static const struct got_error *
1159 append_id(struct got_object_id *id, void *data, void *arg)
1160 {
1161 	struct append_id_arg *a = arg;
1162 
1163 	if (got_object_idset_contains(a->skip, id) ||
1164 	    got_object_idset_contains(a->drop, id))
1165 		return NULL;
1166 
1167 	a->array[++a->idx] = got_object_id_dup(id);
1168 	if (a->array[a->idx] == NULL)
1169 		return got_error_from_errno("got_object_id_dup");
1170 
1171 	return NULL;
1172 }
1173 
1174 static const struct got_error *
1175 queue_commit_or_tag_id(struct got_object_id *id, int color,
1176     struct got_object_id_queue *ids, struct got_repository *repo)
1177 {
1178 	const struct got_error *err;
1179 	struct got_tag_object *tag = NULL;
1180 	int obj_type;
1181 
1182 	err = got_object_get_type(&obj_type, repo, id);
1183 	if (err)
1184 		return err;
1185 
1186 	if (obj_type == GOT_OBJ_TYPE_TAG) {
1187 		err = got_object_open_as_tag(&tag, repo, id);
1188 		if (err)
1189 			return err;
1190 		obj_type = got_object_tag_get_object_type(tag);
1191 		id = got_object_tag_get_object_id(tag);
1192 	}
1193 
1194 	if (obj_type == GOT_OBJ_TYPE_COMMIT) {
1195 		err = queue_commit_id(ids, id, color, repo);
1196 		if (err)
1197 			goto done;
1198 	}
1199 done:
1200 	if (tag)
1201 		got_object_tag_close(tag);
1202 	return err;
1203 }
1204 
1205 static const struct got_error *
1206 paint_commits(int *ncolored, struct got_object_id_queue *ids, int nids,
1207     struct got_object_idset *keep, struct got_object_idset *drop,
1208     struct got_object_idset *skip, struct got_repository *repo,
1209     got_pack_progress_cb progress_cb, void *progress_arg,
1210     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1211 {
1212 	const struct got_error *err = NULL;
1213 	struct got_commit_object *commit = NULL;
1214 	const struct got_object_id_queue *parents;
1215 	struct got_object_qid *qid;
1216 	int nqueued = nids, nskip = 0;
1217 
1218 	while (!STAILQ_EMPTY(ids) && nskip != nqueued) {
1219 		int color;
1220 
1221 		if (cancel_cb) {
1222 			err = cancel_cb(cancel_arg);
1223 			if (err)
1224 				break;
1225 		}
1226 
1227 		qid = STAILQ_FIRST(ids);
1228 		STAILQ_REMOVE_HEAD(ids, entry);
1229 		nqueued--;
1230 		color = *((int *)qid->data);
1231 		if (color == COLOR_SKIP)
1232 			nskip--;
1233 
1234 		if (got_object_idset_contains(skip, &qid->id)) {
1235 			got_object_qid_free(qid);
1236 			continue;
1237 		}
1238 
1239 		switch (color) {
1240 		case COLOR_KEEP:
1241 			if (got_object_idset_contains(keep, &qid->id)) {
1242 				got_object_qid_free(qid);
1243 				continue;
1244 			}
1245 			if (got_object_idset_contains(drop, &qid->id)) {
1246 				err = paint_commit(qid, COLOR_SKIP);
1247 				if (err)
1248 					goto done;
1249 				nskip++;
1250 			} else
1251 				(*ncolored)++;
1252 			err = got_object_idset_add(keep, &qid->id, NULL);
1253 			if (err)
1254 				goto done;
1255 			break;
1256 		case COLOR_DROP:
1257 			if (got_object_idset_contains(drop, &qid->id)) {
1258 				got_object_qid_free(qid);
1259 				continue;
1260 			}
1261 			if (got_object_idset_contains(keep, &qid->id)) {
1262 				err = paint_commit(qid, COLOR_SKIP);
1263 				if (err)
1264 					goto done;
1265 				nskip++;
1266 			} else
1267 				(*ncolored)++;
1268 			err = got_object_idset_add(drop, &qid->id, NULL);
1269 			if (err)
1270 				goto done;
1271 			break;
1272 		case COLOR_SKIP:
1273 			if (!got_object_idset_contains(skip, &qid->id)) {
1274 				err = got_object_idset_add(skip, &qid->id,
1275 				    NULL);
1276 				if (err)
1277 					goto done;
1278 			}
1279 			break;
1280 		default:
1281 			/* should not happen */
1282 			err = got_error_fmt(GOT_ERR_NOT_IMPL,
1283 			    "%s invalid commit color %d", __func__, color);
1284 			goto done;
1285 		}
1286 
1287 		err = report_progress(progress_cb, progress_arg, rl,
1288 		    *ncolored, 0, 0, 0L, 0, 0, 0, 0);
1289 		if (err)
1290 			break;
1291 
1292 
1293 		err = got_object_open_as_commit(&commit, repo, &qid->id);
1294 		if (err)
1295 			break;
1296 
1297 		parents = got_object_commit_get_parent_ids(commit);
1298 		if (parents) {
1299 			struct got_object_qid *pid;
1300 			color = *((int *)qid->data);
1301 			STAILQ_FOREACH(pid, parents, entry) {
1302 				err = queue_commit_id(ids, &pid->id, color,
1303 				    repo);
1304 				if (err)
1305 					break;
1306 				nqueued++;
1307 				if (color == COLOR_SKIP)
1308 					nskip++;
1309 			}
1310 		}
1311 
1312 		got_object_commit_close(commit);
1313 		commit = NULL;
1314 		got_object_qid_free(qid);
1315 	}
1316 done:
1317 	if (commit)
1318 		got_object_commit_close(commit);
1319 	return err;
1320 }
1321 
1322 static const struct got_error *
1323 findtwixt(struct got_object_id ***res, int *nres, int *ncolored,
1324     struct got_object_id **head, int nhead,
1325     struct got_object_id **tail, int ntail,
1326     struct got_repository *repo,
1327     got_pack_progress_cb progress_cb, void *progress_arg,
1328     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1329 {
1330 	const struct got_error *err = NULL;
1331 	struct got_object_id_queue ids;
1332 	struct got_object_idset *keep, *drop, *skip = NULL;
1333 	int i, nkeep;
1334 
1335 	STAILQ_INIT(&ids);
1336 	*res = NULL;
1337 	*nres = 0;
1338 	*ncolored = 0;
1339 
1340 	keep = got_object_idset_alloc();
1341 	if (keep == NULL)
1342 		return got_error_from_errno("got_object_idset_alloc");
1343 
1344 	drop = got_object_idset_alloc();
1345 	if (drop == NULL) {
1346 		err = got_error_from_errno("got_object_idset_alloc");
1347 		goto done;
1348 	}
1349 
1350 	skip = got_object_idset_alloc();
1351 	if (skip == NULL) {
1352 		err = got_error_from_errno("got_object_idset_alloc");
1353 		goto done;
1354 	}
1355 
1356 	for (i = 0; i < nhead; i++) {
1357 		struct got_object_id *id = head[i];
1358 		if (id == NULL)
1359 			continue;
1360 		err = queue_commit_or_tag_id(id, COLOR_KEEP, &ids, repo);
1361 		if (err)
1362 			goto done;
1363 	}		
1364 
1365 	for (i = 0; i < ntail; i++) {
1366 		struct got_object_id *id = tail[i];
1367 		if (id == NULL)
1368 			continue;
1369 		err = queue_commit_or_tag_id(id, COLOR_DROP, &ids, repo);
1370 		if (err)
1371 			goto done;
1372 	}
1373 
1374 	err = paint_commits(ncolored, &ids, nhead + ntail,
1375 	    keep, drop, skip, repo, progress_cb, progress_arg, rl,
1376 	    cancel_cb, cancel_arg);
1377 	if (err)
1378 		goto done;
1379 
1380 	nkeep = got_object_idset_num_elements(keep);
1381 	if (nkeep > 0) {
1382 		struct append_id_arg arg;
1383 		arg.array = calloc(nkeep, sizeof(struct got_object_id *));
1384 		if (arg.array == NULL) {
1385 			err = got_error_from_errno("calloc");
1386 			goto done;
1387 		}
1388 		arg.idx = -1;
1389 		arg.skip = skip;
1390 		arg.drop = drop;
1391 		err = got_object_idset_for_each(keep, append_id, &arg);
1392 		if (err) {
1393 			free(arg.array);
1394 			goto done;
1395 		}
1396 		*res = arg.array;
1397 		*nres = arg.idx + 1;
1398 	}
1399 done:
1400 	got_object_idset_free(keep);
1401 	got_object_idset_free(drop);
1402 	if (skip)
1403 		got_object_idset_free(skip);
1404 	got_object_id_queue_free(&ids);
1405 	return err;
1406 }
1407 
1408 static const struct got_error *
1409 load_object_ids(int *ncolored, int *nfound, int *ntrees,
1410     struct got_object_idset *idset, struct got_object_id **theirs, int ntheirs,
1411     struct got_object_id **ours, int nours, struct got_repository *repo,
1412     int loose_obj_only, got_pack_progress_cb progress_cb, void *progress_arg,
1413     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1414 {
1415 	const struct got_error *err = NULL;
1416 	struct got_object_id **ids = NULL;
1417 	int i, nobj = 0, obj_type;
1418 
1419 	*ncolored = 0;
1420 	*nfound = 0;
1421 	*ntrees = 0;
1422 
1423 	err = findtwixt(&ids, &nobj, ncolored, ours, nours, theirs, ntheirs,
1424 	    repo, progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
1425 	if (err || nobj == 0)
1426 		goto done;
1427 
1428 	for (i = 0; i < ntheirs; i++) {
1429 		struct got_object_id *id = theirs[i];
1430 		if (id == NULL)
1431 			continue;
1432 		err = got_object_get_type(&obj_type, repo, id);
1433 		if (err)
1434 			return err;
1435 		if (obj_type == GOT_OBJ_TYPE_COMMIT) {
1436 			err = load_commit(0, idset, id, repo,
1437 			    loose_obj_only, ncolored, nfound, ntrees,
1438 			    progress_cb, progress_arg, rl,
1439 			    cancel_cb, cancel_arg);
1440 			if (err)
1441 				goto done;
1442 		} else if (obj_type == GOT_OBJ_TYPE_TAG) {
1443 			err = load_tag(0, idset, id, repo,
1444 			    loose_obj_only, ncolored, nfound, ntrees,
1445 			    progress_cb, progress_arg, rl,
1446 			    cancel_cb, cancel_arg);
1447 			if (err)
1448 				goto done;
1449 		}
1450 	}
1451 
1452 	for (i = 0; i < nobj; i++) {
1453 		err = load_commit(1, idset, ids[i], repo, loose_obj_only,
1454 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl,
1455 		    cancel_cb, cancel_arg);
1456 		if (err)
1457 			goto done;
1458 	}
1459 
1460 	for (i = 0; i < nours; i++) {
1461 		struct got_object_id *id = ours[i];
1462 		struct got_pack_meta *m;
1463 		if (id == NULL)
1464 			continue;
1465 		m = got_object_idset_get(idset, id);
1466 		if (m == NULL) {
1467 			err = got_object_get_type(&obj_type, repo, id);
1468 			if (err)
1469 				goto done;
1470 		} else
1471 			obj_type = m->obj_type;
1472 		if (obj_type != GOT_OBJ_TYPE_TAG)
1473 			continue;
1474 		err = load_tag(1, idset, id, repo, loose_obj_only,
1475 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl,
1476 		    cancel_cb, cancel_arg);
1477 		if (err)
1478 			goto done;
1479 	}
1480 done:
1481 	for (i = 0; i < nobj; i++) {
1482 		free(ids[i]);
1483 	}
1484 	free(ids);
1485 	return err;
1486 }
1487 
1488 const struct got_error *
1489 hwrite(FILE *f, void *buf, int len, SHA1_CTX *ctx)
1490 {
1491 	size_t n;
1492 
1493 	SHA1Update(ctx, buf, len);
1494 	n = fwrite(buf, 1, len, f);
1495 	if (n != len)
1496 		return got_ferror(f, GOT_ERR_IO);
1497 	return NULL;
1498 }
1499 
1500 static void
1501 putbe32(char *b, uint32_t n)
1502 {
1503 	b[0] = n >> 24;
1504 	b[1] = n >> 16;
1505 	b[2] = n >> 8;
1506 	b[3] = n >> 0;
1507 }
1508 
1509 static int
1510 write_order_cmp(const void *pa, const void *pb)
1511 {
1512 	struct got_pack_meta *a, *b, *ahd, *bhd;
1513 
1514 	a = *(struct got_pack_meta **)pa;
1515 	b = *(struct got_pack_meta **)pb;
1516 	ahd = (a->head == NULL) ? a : a->head;
1517 	bhd = (b->head == NULL) ? b : b->head;
1518 	if (bhd->mtime < ahd->mtime)
1519 		return -1;
1520 	if (bhd->mtime > ahd->mtime)
1521 		return 1;
1522 	if (bhd < ahd)
1523 		return -1;
1524 	if (bhd > ahd)
1525 		return 1;
1526 	if (a->nchain != b->nchain)
1527 		return a->nchain - b->nchain;
1528 	if (a->mtime < b->mtime)
1529 		return -1;
1530 	if (a->mtime > b->mtime)
1531 		return 1;
1532 	return got_object_id_cmp(&a->id, &b->id);
1533 }
1534 
1535 static int
1536 reuse_write_order_cmp(const void *pa, const void *pb)
1537 {
1538 	struct got_pack_meta *a, *b;
1539 
1540 	a = *(struct got_pack_meta **)pa;
1541 	b = *(struct got_pack_meta **)pb;
1542 
1543 	if (a->reused_delta_offset < b->reused_delta_offset)
1544 		return -1;
1545 	if (a->reused_delta_offset > b->reused_delta_offset)
1546 		return 1;
1547 	return 0;
1548 }
1549 
1550 static const struct got_error *
1551 packhdr(int *hdrlen, char *hdr, size_t bufsize, int obj_type, size_t len)
1552 {
1553 	size_t i;
1554 
1555 	*hdrlen = 0;
1556 
1557 	hdr[0] = obj_type << 4;
1558 	hdr[0] |= len & 0xf;
1559 	len >>= 4;
1560 	for (i = 1; len != 0; i++){
1561 		if (i >= bufsize)
1562 			return got_error(GOT_ERR_NO_SPACE);
1563 		hdr[i - 1] |= GOT_DELTA_SIZE_MORE;
1564 		hdr[i] = len & GOT_DELTA_SIZE_VAL_MASK;
1565 		len >>= GOT_DELTA_SIZE_SHIFT;
1566 	}
1567 
1568 	*hdrlen = i;
1569 	return NULL;
1570 }
1571 
1572 static int
1573 packoff(char *hdr, off_t off)
1574 {
1575 	int i, j;
1576 	char rbuf[8];
1577 
1578 	rbuf[0] = off & GOT_DELTA_SIZE_VAL_MASK;
1579 	for (i = 1; (off >>= GOT_DELTA_SIZE_SHIFT) != 0; i++) {
1580 		rbuf[i] = (--off & GOT_DELTA_SIZE_VAL_MASK) |
1581 		    GOT_DELTA_SIZE_MORE;
1582 	}
1583 
1584 	j = 0;
1585 	while (i > 0)
1586 		hdr[j++] = rbuf[--i];
1587 	return j;
1588 }
1589 
1590 static const struct got_error *
1591 deltahdr(off_t *packfile_size, SHA1_CTX *ctx, FILE *packfile,
1592     struct got_pack_meta *m)
1593 {
1594 	const struct got_error *err;
1595 	char buf[32];
1596 	int nh;
1597 
1598 	if (m->prev->off != 0) {
1599 		err = packhdr(&nh, buf, sizeof(buf),
1600 		    GOT_OBJ_TYPE_OFFSET_DELTA, m->delta_len);
1601 		if (err)
1602 			return err;
1603 		nh += packoff(buf + nh, m->off - m->prev->off);
1604 		err = hwrite(packfile, buf, nh, ctx);
1605 		if (err)
1606 			return err;
1607 		*packfile_size += nh;
1608 	} else {
1609 		err = packhdr(&nh, buf, sizeof(buf),
1610 		    GOT_OBJ_TYPE_REF_DELTA, m->delta_len);
1611 		if (err)
1612 			return err;
1613 		err = hwrite(packfile, buf, nh, ctx);
1614 		if (err)
1615 			return err;
1616 		*packfile_size += nh;
1617 		err = hwrite(packfile, m->prev->id.sha1,
1618 		    sizeof(m->prev->id.sha1), ctx);
1619 		if (err)
1620 			return err;
1621 		*packfile_size += sizeof(m->prev->id.sha1);
1622 	}
1623 
1624 	return NULL;
1625 }
1626 
1627 static const struct got_error *
1628 write_packed_object(off_t *packfile_size, FILE *packfile,
1629     FILE *delta_cache, struct got_pack_meta *m, int *outfd,
1630     SHA1_CTX *ctx, struct got_repository *repo)
1631 {
1632 	const struct got_error *err = NULL;
1633 	struct got_deflate_checksum csum;
1634 	char buf[32];
1635 	int nh;
1636 	struct got_raw_object *raw = NULL;
1637 	off_t outlen;
1638 
1639 	csum.output_sha1 = ctx;
1640 	csum.output_crc = NULL;
1641 
1642 	m->off = ftello(packfile);
1643 	if (m->delta_len == 0) {
1644 		err = got_object_raw_open(&raw, outfd, repo, &m->id);
1645 		if (err)
1646 			goto done;
1647 		err = packhdr(&nh, buf, sizeof(buf),
1648 		    m->obj_type, raw->size);
1649 		if (err)
1650 			goto done;
1651 		err = hwrite(packfile, buf, nh, ctx);
1652 		if (err)
1653 			goto done;
1654 		*packfile_size += nh;
1655 		if (raw->f == NULL) {
1656 			err = got_deflate_to_file_mmap(&outlen,
1657 			    raw->data + raw->hdrlen, 0, raw->size,
1658 			    packfile, &csum);
1659 			if (err)
1660 				goto done;
1661 		} else {
1662 			if (fseeko(raw->f, raw->hdrlen, SEEK_SET)
1663 			    == -1) {
1664 				err = got_error_from_errno("fseeko");
1665 				goto done;
1666 			}
1667 			err = got_deflate_to_file(&outlen, raw->f,
1668 			    raw->size, packfile, &csum);
1669 			if (err)
1670 				goto done;
1671 		}
1672 		*packfile_size += outlen;
1673 		got_object_raw_close(raw);
1674 		raw = NULL;
1675 	} else if (m->delta_buf) {
1676 		err = deltahdr(packfile_size, ctx, packfile, m);
1677 		if (err)
1678 			goto done;
1679 		err = got_deflate_to_file_mmap(&outlen,
1680 		    m->delta_buf, 0, m->delta_len, packfile, &csum);
1681 		if (err)
1682 			goto done;
1683 		*packfile_size += outlen;
1684 		free(m->delta_buf);
1685 		m->delta_buf = NULL;
1686 	} else {
1687 		if (fseeko(delta_cache, m->delta_offset, SEEK_SET)
1688 		    == -1) {
1689 			err = got_error_from_errno("fseeko");
1690 			goto done;
1691 		}
1692 		err = deltahdr(packfile_size, ctx, packfile, m);
1693 		if (err)
1694 			goto done;
1695 		err = got_deflate_to_file(&outlen, delta_cache,
1696 		    m->delta_len, packfile, &csum);
1697 		if (err)
1698 			goto done;
1699 		*packfile_size += outlen;
1700 	}
1701 done:
1702 	if (raw)
1703 		got_object_raw_close(raw);
1704 	return err;
1705 }
1706 
1707 static const struct got_error *
1708 genpack(uint8_t *pack_sha1, FILE *packfile, FILE *delta_cache,
1709     struct got_pack_meta **deltify, int ndeltify,
1710     struct got_pack_meta **reuse, int nreuse,
1711     int ncolored, int nfound, int ntrees, int nours,
1712     struct got_repository *repo,
1713     got_pack_progress_cb progress_cb, void *progress_arg,
1714     struct got_ratelimit *rl,
1715     got_cancel_cb cancel_cb, void *cancel_arg)
1716 {
1717 	const struct got_error *err = NULL;
1718 	int i;
1719 	SHA1_CTX ctx;
1720 	struct got_pack_meta *m;
1721 	char buf[32];
1722 	size_t n;
1723 	off_t packfile_size = 0;
1724 	int outfd = -1;
1725 
1726 	SHA1Init(&ctx);
1727 
1728 	err = hwrite(packfile, "PACK", 4, &ctx);
1729 	if (err)
1730 		return err;
1731 	putbe32(buf, GOT_PACKFILE_VERSION);
1732 	err = hwrite(packfile, buf, 4, &ctx);
1733 	if (err)
1734 		goto done;
1735 	putbe32(buf, ndeltify + nreuse);
1736 	err = hwrite(packfile, buf, 4, &ctx);
1737 	if (err)
1738 		goto done;
1739 
1740 	qsort(deltify, ndeltify, sizeof(struct got_pack_meta *),
1741 	    write_order_cmp);
1742 	for (i = 0; i < ndeltify; i++) {
1743 		err = report_progress(progress_cb, progress_arg, rl,
1744 		    ncolored, nfound, ntrees, packfile_size, nours,
1745 		    ndeltify + nreuse, ndeltify + nreuse, i);
1746 		if (err)
1747 			goto done;
1748 		m = deltify[i];
1749 		err = write_packed_object(&packfile_size, packfile,
1750 		    delta_cache, m, &outfd, &ctx, repo);
1751 		if (err)
1752 			goto done;
1753 	}
1754 
1755 	qsort(reuse, nreuse, sizeof(struct got_pack_meta *),
1756 	    reuse_write_order_cmp);
1757 	for (i = 0; i < nreuse; i++) {
1758 		err = report_progress(progress_cb, progress_arg, rl,
1759 		    ncolored, nfound, ntrees, packfile_size, nours,
1760 		    ndeltify + nreuse, ndeltify + nreuse, ndeltify + i);
1761 		if (err)
1762 			goto done;
1763 		m = reuse[i];
1764 		err = write_packed_object(&packfile_size, packfile,
1765 		    delta_cache, m, &outfd, &ctx, repo);
1766 		if (err)
1767 			goto done;
1768 	}
1769 
1770 	SHA1Final(pack_sha1, &ctx);
1771 	n = fwrite(pack_sha1, 1, SHA1_DIGEST_LENGTH, packfile);
1772 	if (n != SHA1_DIGEST_LENGTH)
1773 		err = got_ferror(packfile, GOT_ERR_IO);
1774 	packfile_size += SHA1_DIGEST_LENGTH;
1775 	packfile_size += sizeof(struct got_packfile_hdr);
1776 	if (progress_cb) {
1777 		err = progress_cb(progress_arg, ncolored, nfound, ntrees,
1778 		    packfile_size, nours, ndeltify + nreuse,
1779 		    ndeltify + nreuse, ndeltify + nreuse);
1780 		if (err)
1781 			goto done;
1782 	}
1783 done:
1784 	if (outfd != -1 && close(outfd) == -1 && err == NULL)
1785 		err = got_error_from_errno("close");
1786 	return err;
1787 }
1788 
1789 static const struct got_error *
1790 remove_unused_object(struct got_object_id *id, void *data, void *arg)
1791 {
1792 	struct got_object_idset *idset = arg;
1793 
1794 	if (data == NULL)
1795 		got_object_idset_remove(NULL, idset, id);
1796 
1797 	return NULL;
1798 }
1799 
1800 static const struct got_error *
1801 remove_reused_object(struct got_object_id *id, void *data, void *arg)
1802 {
1803 	struct got_object_idset *idset = arg;
1804 	struct got_pack_meta *m = data;
1805 
1806 	if (m->have_reused_delta)
1807 		got_object_idset_remove(NULL, idset, id);
1808 
1809 	return NULL;
1810 }
1811 
1812 static const struct got_error *
1813 add_meta_idset_cb(struct got_object_id *id, void *data, void *arg)
1814 {
1815 	struct got_pack_meta *m = data;
1816 	struct got_pack_metavec *v = arg;
1817 
1818 	return add_meta(m, v);
1819 }
1820 
1821 const struct got_error *
1822 got_pack_create(uint8_t *packsha1, FILE *packfile,
1823     struct got_object_id **theirs, int ntheirs,
1824     struct got_object_id **ours, int nours,
1825     struct got_repository *repo, int loose_obj_only, int allow_empty,
1826     got_pack_progress_cb progress_cb, void *progress_arg,
1827     got_cancel_cb cancel_cb, void *cancel_arg)
1828 {
1829 	const struct got_error *err;
1830 	int delta_cache_fd = -1;
1831 	FILE *delta_cache = NULL;
1832 	struct got_object_idset *idset;
1833 	struct got_ratelimit rl;
1834 	struct got_pack_metavec deltify, reuse;
1835 	int ncolored = 0, nfound = 0, ntrees = 0;
1836 
1837 	memset(&deltify, 0, sizeof(deltify));
1838 	memset(&reuse, 0, sizeof(reuse));
1839 
1840 	got_ratelimit_init(&rl, 0, 500);
1841 
1842 	idset = got_object_idset_alloc();
1843 	if (idset == NULL)
1844 		return got_error_from_errno("got_object_idset_alloc");
1845 
1846 	err = load_object_ids(&ncolored, &nfound, &ntrees, idset, theirs,
1847 	    ntheirs, ours, nours, repo, loose_obj_only,
1848 	    progress_cb, progress_arg, &rl, cancel_cb, cancel_arg);
1849 	if (err)
1850 		return err;
1851 
1852 	err = got_object_idset_for_each(idset, remove_unused_object, idset);
1853 	if (err)
1854 		goto done;
1855 
1856 	if (progress_cb) {
1857 		err = progress_cb(progress_arg, ncolored, nfound, ntrees,
1858 		    0L, nours, got_object_idset_num_elements(idset), 0, 0);
1859 		if (err)
1860 			goto done;
1861 	}
1862 
1863 	if (got_object_idset_num_elements(idset) == 0 && !allow_empty) {
1864 		err = got_error(GOT_ERR_CANNOT_PACK);
1865 		goto done;
1866 	}
1867 
1868 	delta_cache_fd = got_opentempfd();
1869 	if (delta_cache_fd == -1) {
1870 		err = got_error_from_errno("got_opentemp");
1871 		goto done;
1872 	}
1873 
1874 	reuse.metasz = 64;
1875 	reuse.meta = calloc(reuse.metasz,
1876 	    sizeof(struct got_pack_meta *));
1877 	if (reuse.meta == NULL) {
1878 		err = got_error_from_errno("calloc");
1879 		goto done;
1880 	}
1881 
1882 	err = search_deltas(&reuse, idset, delta_cache_fd, ncolored, nfound,
1883 	    ntrees, nours, repo, progress_cb, progress_arg, &rl,
1884 	    cancel_cb, cancel_arg);
1885 	if (err)
1886 		goto done;
1887 	if (reuse.nmeta > 0) {
1888 		err = got_object_idset_for_each(idset,
1889 		    remove_reused_object, idset);
1890 		if (err)
1891 			goto done;
1892 	}
1893 
1894 	delta_cache = fdopen(delta_cache_fd, "a+");
1895 	if (delta_cache == NULL) {
1896 		err = got_error_from_errno("fdopen");
1897 		goto done;
1898 	}
1899 	delta_cache_fd = -1;
1900 
1901 	if (fseeko(delta_cache, 0L, SEEK_END) == -1) {
1902 		err = got_error_from_errno("fseeko");
1903 		goto done;
1904 	}
1905 
1906 	deltify.meta = calloc(got_object_idset_num_elements(idset),
1907 	    sizeof(struct got_pack_meta *));
1908 	if (deltify.meta == NULL) {
1909 		err = got_error_from_errno("calloc");
1910 		goto done;
1911 	}
1912 	deltify.metasz = got_object_idset_num_elements(idset);
1913 
1914 	err = got_object_idset_for_each(idset, add_meta_idset_cb, &deltify);
1915 	if (err)
1916 		goto done;
1917 	if (deltify.nmeta > 0) {
1918 		err = pick_deltas(deltify.meta, deltify.nmeta, ncolored,
1919 		    nfound, ntrees, nours, reuse.nmeta, delta_cache, repo,
1920 		    progress_cb, progress_arg, &rl, cancel_cb, cancel_arg);
1921 		if (err)
1922 			goto done;
1923 		if (fseeko(delta_cache, 0L, SEEK_SET) == -1) {
1924 			err = got_error_from_errno("fseeko");
1925 			goto done;
1926 		}
1927 	}
1928 
1929 	err = genpack(packsha1, packfile, delta_cache, deltify.meta,
1930 	    deltify.nmeta, reuse.meta, reuse.nmeta, ncolored, nfound, ntrees,
1931 	    nours, repo, progress_cb, progress_arg, &rl,
1932 	    cancel_cb, cancel_arg);
1933 	if (err)
1934 		goto done;
1935 done:
1936 	free_nmeta(deltify.meta, deltify.nmeta);
1937 	free_nmeta(reuse.meta, reuse.nmeta);
1938 	got_object_idset_free(idset);
1939 	if (delta_cache_fd != -1 && close(delta_cache_fd) == -1 && err == NULL)
1940 		err = got_error_from_errno("close");
1941 	if (delta_cache && fclose(delta_cache) == EOF && err == NULL)
1942 		err = got_error_from_errno("fclose");
1943 	return err;
1944 }