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Date:: Wed Apr 20 14:00:12 2022 UTC
Message:: inline struct got_object_id in struct got_object_qid Saves us from doing a malloc/free call for every item on the list. ok op@
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1 /*
2  * Copyright (c) 2020 Ori Bernstein
3  * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/types.h>
19 #include <sys/queue.h>
20 #include <sys/tree.h>
21 #include <sys/uio.h>
22 #include <sys/stat.h>
23 #include <sys/time.h>
24 
25 #include <endian.h>
26 #include <stdint.h>
27 #include <imsg.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <sha1.h>
32 #include <time.h>
33 #include <unistd.h>
34 #include <limits.h>
35 #include <zlib.h>
36 
37 #include "got_error.h"
38 #include "got_cancel.h"
39 #include "got_object.h"
40 #include "got_path.h"
41 #include "got_reference.h"
42 #include "got_repository_admin.h"
43 #include "got_opentemp.h"
44 
45 #include "got_lib_deltify.h"
46 #include "got_lib_delta.h"
47 #include "got_lib_object.h"
48 #include "got_lib_object_idset.h"
49 #include "got_lib_object_cache.h"
50 #include "got_lib_deflate.h"
51 #include "got_lib_pack.h"
52 #include "got_lib_privsep.h"
53 #include "got_lib_repository.h"
54 #include "got_lib_ratelimit.h"
55 
56 #ifndef MIN
57 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
58 #endif
59 
60 #ifndef MAX
61 #define	MAX(_a,_b) ((_a) > (_b) ? (_a) : (_b))
62 #endif
63 
64 #ifndef nitems
65 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
66 #endif
67 
68 struct got_pack_meta {
69 	struct got_object_id id;
70 	char	*path;
71 	int	obj_type;
72 	off_t	size;
73 	time_t	mtime;
74 
75 	/* The best delta we picked */
76 	struct got_pack_meta *head;
77 	struct got_pack_meta *prev;
78 	unsigned char *delta_buf; /* if not encoded in delta cache file */
79 	off_t	delta_offset;	/* offset in delta cache file */
80 	off_t	delta_len;	/* encoded delta length */
81 	int	nchain;
82 
83 	int	have_reused_delta;
84 	off_t   reused_delta_offset; /* offset of delta in reused pack file */
85 	struct got_object_id *base_obj_id;
86 
87 	/* Only used for delta window */
88 	struct got_delta_table *dtab;
89 
90 	/* Only used for writing offset deltas */
91 	off_t	off;
92 };
93 
94 struct got_pack_metavec {
95 	struct got_pack_meta **meta;
96 	int nmeta;
97 	int metasz;
98 };
99 
100 static const struct got_error *
101 alloc_meta(struct got_pack_meta **new, struct got_object_id *id,
102     const char *path, int obj_type, time_t mtime)
103 {
104 	const struct got_error *err = NULL;
105 	struct got_pack_meta *m;
106 
107 	*new = NULL;
108 
109 	m = calloc(1, sizeof(*m));
110 	if (m == NULL)
111 		return got_error_from_errno("calloc");
112 
113 	memcpy(&m->id, id, sizeof(m->id));
114 
115 	m->path = strdup(path);
116 	if (m->path == NULL) {
117 		err = got_error_from_errno("strdup");
118 		free(m);
119 		return err;
120 	}
121 
122 	m->obj_type = obj_type;
123 	m->mtime = mtime;
124 	*new = m;
125 	return NULL;
126 }
127 
128 static void
129 clear_meta(struct got_pack_meta *meta)
130 {
131 	if (meta == NULL)
132 		return;
133 	free(meta->path);
134 	meta->path = NULL;
135 	free(meta->delta_buf);
136 	meta->delta_buf = NULL;
137 	free(meta->base_obj_id);
138 	meta->base_obj_id = NULL;
139 }
140 
141 static void
142 free_nmeta(struct got_pack_meta **meta, int nmeta)
143 {
144 	int i;
145 
146 	for (i = 0; i < nmeta; i++)
147 		clear_meta(meta[i]);
148 	free(meta);
149 }
150 
151 static int
152 delta_order_cmp(const void *pa, const void *pb)
153 {
154 	struct got_pack_meta *a, *b;
155 	int cmp;
156 
157 	a = *(struct got_pack_meta **)pa;
158 	b = *(struct got_pack_meta **)pb;
159 
160 	if (a->obj_type != b->obj_type)
161 		return a->obj_type - b->obj_type;
162 	cmp = strcmp(a->path, b->path);
163 	if (cmp != 0)
164 		return cmp;
165 	if (a->mtime != b->mtime)
166 		return a->mtime - b->mtime;
167 	return got_object_id_cmp(&a->id, &b->id);
168 }
169 
170 static off_t
171 delta_size(struct got_delta_instruction *deltas, int ndeltas)
172 {
173 	int i;
174 	off_t size = 32;
175 	for (i = 0; i < ndeltas; i++) {
176 		if (deltas[i].copy)
177 			size += GOT_DELTA_SIZE_SHIFT;
178 		else
179 			size += deltas[i].len + 1;
180 	}
181 	return size;
182 }
183 
184 static const struct got_error *
185 append(unsigned char **p, size_t *len, off_t *sz, void *seg, int nseg)
186 {
187 	char *n;
188 
189 	if (*len + nseg >= *sz) {
190 		while (*len + nseg >= *sz)
191 			*sz += *sz / 2;
192 		n = realloc(*p, *sz);
193 		if (n == NULL)
194 			return got_error_from_errno("realloc");
195 		*p = n;
196 	}
197 	memcpy(*p + *len, seg, nseg);
198 	*len += nseg;
199 	return NULL;
200 }
201 
202 static const struct got_error *
203 encode_delta_in_mem(struct got_pack_meta *m, struct got_raw_object *o,
204     struct got_delta_instruction *deltas, int ndeltas,
205     off_t delta_size, off_t base_size)
206 {
207 	const struct got_error *err;
208 	unsigned char buf[16], *bp;
209 	int i, j;
210 	size_t len = 0;
211 	off_t n;
212 	struct got_delta_instruction *d;
213 
214 	m->delta_buf = malloc(delta_size);
215 	if (m->delta_buf == NULL)
216 		return got_error_from_errno("calloc");
217 
218 	/* base object size */
219 	buf[0] = base_size & GOT_DELTA_SIZE_VAL_MASK;
220 	n = base_size >> GOT_DELTA_SIZE_SHIFT;
221 	for (i = 1; n > 0; i++) {
222 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
223 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
224 		n >>= GOT_DELTA_SIZE_SHIFT;
225 	}
226 	err = append(&m->delta_buf, &len, &delta_size, buf, i);
227 	if (err)
228 		return err;
229 
230 	/* target object size */
231 	buf[0] = o->size & GOT_DELTA_SIZE_VAL_MASK;
232 	n = o->size >> GOT_DELTA_SIZE_SHIFT;
233 	for (i = 1; n > 0; i++) {
234 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
235 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
236 		n >>= GOT_DELTA_SIZE_SHIFT;
237 	}
238 	err = append(&m->delta_buf, &len, &delta_size, buf, i);
239 	if (err)
240 		return err;
241 
242 	for (j = 0; j < ndeltas; j++) {
243 		d = &deltas[j];
244 		if (d->copy) {
245 			n = d->offset;
246 			bp = &buf[1];
247 			buf[0] = GOT_DELTA_BASE_COPY;
248 			for (i = 0; i < 4; i++) {
249 				/* DELTA_COPY_OFF1 ... DELTA_COPY_OFF4 */
250 				buf[0] |= 1 << i;
251 				*bp++ = n & 0xff;
252 				n >>= 8;
253 				if (n == 0)
254 					break;
255 			}
256 
257 			n = d->len;
258 			if (n != GOT_DELTA_COPY_DEFAULT_LEN) {
259 				/* DELTA_COPY_LEN1 ... DELTA_COPY_LEN3 */
260 				for (i = 0; i < 3 && n > 0; i++) {
261 					buf[0] |= 1 << (i + 4);
262 					*bp++ = n & 0xff;
263 					n >>= 8;
264 				}
265 			}
266 			err = append(&m->delta_buf, &len, &delta_size,
267 			    buf, bp - buf);
268 			if (err)
269 				return err;
270 		} else if (o->f == NULL) {
271 			n = 0;
272 			while (n != d->len) {
273 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
274 				err = append(&m->delta_buf, &len, &delta_size,
275 				    buf, 1);
276 				if (err)
277 					return err;
278 				err = append(&m->delta_buf, &len, &delta_size,
279 				    o->data + o->hdrlen + d->offset + n,
280 				    buf[0]);
281 				if (err)
282 					return err;
283 				n += buf[0];
284 			}
285 		} else {
286 			char content[128];
287 			size_t r;
288 			if (fseeko(o->f, o->hdrlen + d->offset, SEEK_SET) == -1)
289 				return got_error_from_errno("fseeko");
290 			n = 0;
291 			while (n != d->len) {
292 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
293 				err = append(&m->delta_buf, &len, &delta_size,
294 				    buf, 1);
295 				if (err)
296 					return err;
297 				r = fread(content, 1, buf[0], o->f);
298 				if (r != buf[0])
299 					return got_ferror(o->f, GOT_ERR_IO);
300 				err = append(&m->delta_buf, &len, &delta_size,
301 				    content, buf[0]);
302 				if (err)
303 					return err;
304 				n += buf[0];
305 			}
306 		}
307 	}
308 
309 	m->delta_len = len;
310 	return NULL;
311 }
312 
313 static const struct got_error *
314 encode_delta(struct got_pack_meta *m, struct got_raw_object *o,
315     struct got_delta_instruction *deltas, int ndeltas,
316     off_t base_size, FILE *f)
317 {
318 	unsigned char buf[16], *bp;
319 	int i, j;
320 	off_t n;
321 	size_t w;
322 	struct got_delta_instruction *d;
323 
324 	/* base object size */
325 	buf[0] = base_size & GOT_DELTA_SIZE_VAL_MASK;
326 	n = base_size >> GOT_DELTA_SIZE_SHIFT;
327 	for (i = 1; n > 0; i++) {
328 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
329 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
330 		n >>= GOT_DELTA_SIZE_SHIFT;
331 	}
332 	w = fwrite(buf, 1, i, f);
333 	if (w != i)
334 		return got_ferror(f, GOT_ERR_IO);
335 
336 	/* target object size */
337 	buf[0] = o->size & GOT_DELTA_SIZE_VAL_MASK;
338 	n = o->size >> GOT_DELTA_SIZE_SHIFT;
339 	for (i = 1; n > 0; i++) {
340 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
341 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
342 		n >>= GOT_DELTA_SIZE_SHIFT;
343 	}
344 	w = fwrite(buf, 1, i, f);
345 	if (w != i)
346 		return got_ferror(f, GOT_ERR_IO);
347 
348 	for (j = 0; j < ndeltas; j++) {
349 		d = &deltas[j];
350 		if (d->copy) {
351 			n = d->offset;
352 			bp = &buf[1];
353 			buf[0] = GOT_DELTA_BASE_COPY;
354 			for (i = 0; i < 4; i++) {
355 				/* DELTA_COPY_OFF1 ... DELTA_COPY_OFF4 */
356 				buf[0] |= 1 << i;
357 				*bp++ = n & 0xff;
358 				n >>= 8;
359 				if (n == 0)
360 					break;
361 			}
362 
363 			n = d->len;
364 			if (n != GOT_DELTA_COPY_DEFAULT_LEN) {
365 				/* DELTA_COPY_LEN1 ... DELTA_COPY_LEN3 */
366 				for (i = 0; i < 3 && n > 0; i++) {
367 					buf[0] |= 1 << (i + 4);
368 					*bp++ = n & 0xff;
369 					n >>= 8;
370 				}
371 			}
372 			w = fwrite(buf, 1, bp - buf, f);
373 			if (w != bp - buf)
374 				return got_ferror(f, GOT_ERR_IO);
375 		} else if (o->f == NULL) {
376 			n = 0;
377 			while (n != d->len) {
378 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
379 				w = fwrite(buf, 1, 1, f);
380 				if (w != 1)
381 					return got_ferror(f, GOT_ERR_IO);
382 				w = fwrite(o->data + o->hdrlen + d->offset + n,
383 				    1, buf[0], f);
384 				if (w != buf[0])
385 					return got_ferror(f, GOT_ERR_IO);
386 				n += buf[0];
387 			}
388 		} else {
389 			char content[128];
390 			size_t r;
391 			if (fseeko(o->f, o->hdrlen + d->offset, SEEK_SET) == -1)
392 				return got_error_from_errno("fseeko");
393 			n = 0;
394 			while (n != d->len) {
395 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
396 				w = fwrite(buf, 1, 1, f);
397 				if (w != 1)
398 					return got_ferror(f, GOT_ERR_IO);
399 				r = fread(content, 1, buf[0], o->f);
400 				if (r != buf[0])
401 					return got_ferror(o->f, GOT_ERR_IO);
402 				w = fwrite(content, 1, buf[0], f);
403 				if (w != buf[0])
404 					return got_ferror(f, GOT_ERR_IO);
405 				n += buf[0];
406 			}
407 		}
408 	}
409 
410 	m->delta_len = ftello(f) - m->delta_offset;
411 	return NULL;
412 }
413 
414 static const struct got_error *
415 report_progress(got_pack_progress_cb progress_cb, void *progress_arg,
416     struct got_ratelimit *rl, int ncolored, int nfound, int ntrees,
417     off_t packfile_size, int ncommits, int nobj_total, int obj_deltify,
418     int nobj_written)
419 {
420 	const struct got_error *err;
421 	int elapsed;
422 
423 	if (progress_cb == NULL)
424 		return NULL;
425 
426 	err = got_ratelimit_check(&elapsed, rl);
427 	if (err || !elapsed)
428 		return err;
429 
430 	return progress_cb(progress_arg, ncolored, nfound, ntrees,
431 	    packfile_size, ncommits, nobj_total, obj_deltify, nobj_written);
432 }
433 
434 static const struct got_error *
435 add_meta(struct got_pack_meta *m, struct got_pack_metavec *v)
436 {
437 	if (v->nmeta == v->metasz){
438 		size_t newsize = 2 * v->metasz;
439 		struct got_pack_meta **new;
440 		new = reallocarray(v->meta, newsize, sizeof(*new));
441 		if (new == NULL)
442 			return got_error_from_errno("reallocarray");
443 		v->meta = new;
444 		v->metasz = newsize; 
445 	}
446 
447 	v->meta[v->nmeta++] = m;
448 	return NULL;
449 }
450 
451 static const struct got_error *
452 reuse_delta(int idx, struct got_pack_meta *m, struct got_pack_metavec *v,
453     struct got_object_idset *idset, struct got_pack *pack,
454     struct got_packidx *packidx, int delta_cache_fd,
455     struct got_repository *repo)
456 {
457 	const struct got_error *err = NULL;
458 	struct got_pack_meta *base = NULL;
459 	struct got_object_id *base_obj_id = NULL;
460 	off_t delta_len = 0, delta_offset = 0, delta_cache_offset = 0;
461 	uint64_t base_size, result_size;
462 
463 	if (m->have_reused_delta)
464 		return NULL;
465 
466 	err = got_object_read_raw_delta(&base_size, &result_size, &delta_len,
467 	    &delta_offset, &delta_cache_offset, &base_obj_id, delta_cache_fd,
468 	    packidx, idx, &m->id, repo);
469 	if (err)
470 		return err;
471 
472 	if (delta_offset + delta_len < delta_offset)
473 		return got_error(GOT_ERR_BAD_PACKFILE);
474 
475 	base = got_object_idset_get(idset, base_obj_id);
476 	if (base == NULL)
477 		goto done;
478 
479 	m->delta_len = delta_len;
480 	m->delta_offset = delta_cache_offset;
481 	m->prev = base;
482 	m->size = result_size;
483 	m->have_reused_delta = 1;
484 	m->reused_delta_offset = delta_offset;
485 	m->base_obj_id = base_obj_id;
486 	base_obj_id = NULL;
487 	err = add_meta(m, v);
488 done:
489 	free(base_obj_id);
490 	return err;
491 }
492 
493 static const struct got_error *
494 find_pack_for_reuse(struct got_packidx **best_packidx,
495     struct got_repository *repo)
496 {
497 	const struct got_error *err = NULL;
498 	struct got_pathlist_entry *pe;
499 	const char *best_packidx_path = NULL;
500 	int nobj_max = 0;
501 
502 	*best_packidx = NULL;
503 
504 	TAILQ_FOREACH(pe, &repo->packidx_paths, entry) {
505 		const char *path_packidx = pe->path;
506 		struct got_packidx *packidx;
507 		int nobj;
508 
509 		err = got_repo_get_packidx(&packidx, path_packidx, repo);
510 		if (err)
511 			break;
512 
513 		nobj = be32toh(packidx->hdr.fanout_table[0xff]);
514 		if (nobj > nobj_max) {
515 			best_packidx_path = path_packidx;
516 			nobj_max = nobj;
517 		}
518 	}
519 
520 	if (best_packidx_path) {
521 		err = got_repo_get_packidx(best_packidx, best_packidx_path,
522 		    repo);
523 	}
524 
525 	return err;
526 }
527 
528 struct search_deltas_arg {
529 	struct got_packidx *packidx;
530 	struct got_pack *pack;
531 	struct got_object_idset *idset;
532 	struct got_pack_metavec *v;
533 	int delta_cache_fd;
534 	struct got_repository *repo;
535 	got_pack_progress_cb progress_cb;
536 	void *progress_arg;
537 	struct got_ratelimit *rl;
538 	got_cancel_cb cancel_cb;
539 	void *cancel_arg;
540 	int ncolored;
541 	int nfound;
542 	int ntrees;
543 	int ncommits;
544 };
545 
546 static const struct got_error *
547 search_delta_for_object(struct got_object_id *id, void *data, void *arg)
548 {
549 	const struct got_error *err;
550 	struct got_pack_meta *m = data;
551 	struct search_deltas_arg *a = arg;
552 	int obj_idx;
553 	struct got_object *obj = NULL;
554 
555 	if (a->cancel_cb) {
556 		err = (*a->cancel_cb)(a->cancel_arg);
557 		if (err)
558 			return err;
559 	}
560 
561 	if (!got_repo_check_packidx_bloom_filter(a->repo,
562 	    a->packidx->path_packidx, id))
563 		return NULL;
564 
565 	obj_idx = got_packidx_get_object_idx(a->packidx, id);
566 	if (obj_idx == -1)
567 		return NULL;
568 
569 	/* TODO:
570 	 * Opening and closing an object just to check its flags
571 	 * is a bit expensive. We could have an imsg which requests
572 	 * plain type/size information for an object without doing
573 	 * work such as traversing the object's entire delta chain
574 	 * to find the base object type, and other such info which
575 	 * we don't really need here.
576 	 */
577 	err = got_object_open_from_packfile(&obj, &m->id, a->pack,
578 	    a->packidx, obj_idx, a->repo);
579 	if (err)
580 		return err;
581 
582 	if (obj->flags & GOT_OBJ_FLAG_DELTIFIED) {
583 		reuse_delta(obj_idx, m, a->v, a->idset, a->pack, a->packidx,
584 		    a->delta_cache_fd, a->repo);
585 		if (err)
586 			goto done;
587 		err = report_progress(a->progress_cb, a->progress_arg, a->rl,
588 		    a->ncolored, a->nfound, a->ntrees, 0L, a->ncommits,
589 		    got_object_idset_num_elements(a->idset), a->v->nmeta, 0);
590 	}
591 done:
592 	got_object_close(obj);
593 	return err;
594 }
595 
596 static const struct got_error *
597 search_deltas(struct got_pack_metavec *v, struct got_object_idset *idset,
598     int delta_cache_fd, int ncolored, int nfound, int ntrees, int ncommits,
599     struct got_repository *repo,
600     got_pack_progress_cb progress_cb, void *progress_arg,
601     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
602 {
603 	const struct got_error *err = NULL;
604 	char *path_packfile = NULL;
605 	struct got_packidx *packidx;
606 	struct got_pack *pack;
607 	struct search_deltas_arg sda;
608 
609 	err = find_pack_for_reuse(&packidx, repo);
610 	if (err)
611 		return err;
612 
613 	if (packidx == NULL)
614 		return NULL;
615 
616 	err = got_packidx_get_packfile_path(&path_packfile,
617 	    packidx->path_packidx);
618 	if (err)
619 		return err;
620 
621 	pack = got_repo_get_cached_pack(repo, path_packfile);
622 	if (pack == NULL) {
623 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
624 		if (err)
625 			goto done;
626 	}
627 
628 	sda.packidx = packidx;
629 	sda.pack = pack;
630 	sda.idset = idset;
631 	sda.v = v;
632 	sda.delta_cache_fd = delta_cache_fd;
633 	sda.repo = repo;
634 	sda.progress_cb = progress_cb;
635 	sda.progress_arg = progress_arg;
636 	sda.rl = rl;
637 	sda.cancel_cb = cancel_cb;
638 	sda.cancel_arg = cancel_arg;
639 	sda.ncolored = ncolored;
640 	sda.nfound = nfound;
641 	sda.ntrees = ntrees;
642 	sda.ncommits = ncommits;
643 	err = got_object_idset_for_each(idset, search_delta_for_object, &sda);
644 done:
645 	free(path_packfile);
646 	return err;
647 }
648 
649 static const struct got_error *
650 pick_deltas(struct got_pack_meta **meta, int nmeta, int ncolored,
651     int nfound, int ntrees, int ncommits, int nreused, FILE *delta_cache,
652     struct got_repository *repo,
653     got_pack_progress_cb progress_cb, void *progress_arg,
654     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
655 {
656 	const struct got_error *err = NULL;
657 	struct got_pack_meta *m = NULL, *base = NULL;
658 	struct got_raw_object *raw = NULL, *base_raw = NULL;
659 	struct got_delta_instruction *deltas = NULL, *best_deltas = NULL;
660 	int i, j, ndeltas, best_ndeltas;
661 	off_t size, best_size;
662 	const int max_base_candidates = 3;
663 	size_t delta_memsize = 0;
664 	const size_t max_delta_memsize = 25 * GOT_DELTA_RESULT_SIZE_CACHED_MAX;
665 	int outfd = -1;
666 
667 	qsort(meta, nmeta, sizeof(struct got_pack_meta *), delta_order_cmp);
668 	for (i = 0; i < nmeta; i++) {
669 		if (cancel_cb) {
670 			err = (*cancel_cb)(cancel_arg);
671 			if (err)
672 				break;
673 		}
674 		err = report_progress(progress_cb, progress_arg, rl,
675 		    ncolored, nfound, ntrees, 0L, ncommits, nreused + nmeta,
676 		    nreused + i, 0);
677 		if (err)
678 			goto done;
679 		m = meta[i];
680 
681 		if (m->obj_type == GOT_OBJ_TYPE_COMMIT ||
682 		    m->obj_type == GOT_OBJ_TYPE_TAG)
683 			continue;
684 
685 		err = got_object_raw_open(&raw, &outfd, repo, &m->id);
686 		if (err)
687 			goto done;
688 		m->size = raw->size;
689 
690 		if (raw->f == NULL) {
691 			err = got_deltify_init_mem(&m->dtab, raw->data,
692 			    raw->hdrlen, raw->size + raw->hdrlen);
693 		} else {
694 			err = got_deltify_init(&m->dtab, raw->f, raw->hdrlen,
695 			    raw->size + raw->hdrlen);
696 		}
697 		if (err)
698 			goto done;
699 
700 		if (i > max_base_candidates) {
701 			struct got_pack_meta *n = NULL;
702 			n = meta[i - (max_base_candidates + 1)];
703 			got_deltify_free(n->dtab);
704 			n->dtab = NULL;
705 		}
706 
707 		best_size = raw->size;
708 		best_ndeltas = 0;
709 		for (j = MAX(0, i - max_base_candidates); j < i; j++) {
710 			if (cancel_cb) {
711 				err = (*cancel_cb)(cancel_arg);
712 				if (err)
713 					goto done;
714 			}
715 			base = meta[j];
716 			/* long chains make unpacking slow, avoid such bases */
717 			if (base->nchain >= 128 ||
718 			    base->obj_type != m->obj_type)
719 				continue;
720 
721 			err = got_object_raw_open(&base_raw, &outfd, repo,
722 			    &base->id);
723 			if (err)
724 				goto done;
725 
726 			if (raw->f == NULL && base_raw->f == NULL) {
727 				err = got_deltify_mem_mem(&deltas, &ndeltas,
728 				    raw->data, raw->hdrlen,
729 				    raw->size + raw->hdrlen,
730 				    base->dtab, base_raw->data,
731 				    base_raw->hdrlen,
732 				    base_raw->size + base_raw->hdrlen);
733 			} else if (raw->f == NULL) {
734 				err = got_deltify_mem_file(&deltas, &ndeltas,
735 				    raw->data, raw->hdrlen,
736 				    raw->size + raw->hdrlen,
737 				    base->dtab, base_raw->f,
738 				    base_raw->hdrlen,
739 				    base_raw->size + base_raw->hdrlen);
740 			} else if (base_raw->f == NULL) {
741 				err = got_deltify_file_mem(&deltas, &ndeltas,
742 				    raw->f, raw->hdrlen,
743 				    raw->size + raw->hdrlen,
744 				    base->dtab, base_raw->data,
745 				    base_raw->hdrlen,
746 				    base_raw->size + base_raw->hdrlen);
747 			} else {
748 				err = got_deltify(&deltas, &ndeltas,
749 				    raw->f, raw->hdrlen,
750 				    raw->size + raw->hdrlen,
751 				    base->dtab, base_raw->f, base_raw->hdrlen,
752 				    base_raw->size + base_raw->hdrlen);
753 			}
754 			got_object_raw_close(base_raw);
755 			base_raw = NULL;
756 			if (err)
757 				goto done;
758 
759 			size = delta_size(deltas, ndeltas);
760 			if (size + 32 < best_size){
761 				/*
762 				 * if we already picked a best delta,
763 				 * replace it.
764 				 */
765 				best_size = size;
766 				free(best_deltas);
767 				best_deltas = deltas;
768 				best_ndeltas = ndeltas;
769 				deltas = NULL;
770 				m->nchain = base->nchain + 1;
771 				m->prev = base;
772 				m->head = base->head;
773 				if (m->head == NULL)
774 					m->head = base;
775 			} else {
776 				free(deltas);
777 				deltas = NULL;
778 				ndeltas = 0;
779 			}
780 		}
781 
782 		if (best_ndeltas > 0) {
783 			if (best_size <= GOT_DELTA_RESULT_SIZE_CACHED_MAX &&
784 			    delta_memsize + best_size <= max_delta_memsize) {
785 				delta_memsize += best_size;
786 				err = encode_delta_in_mem(m, raw, best_deltas,
787 				    best_ndeltas, best_size, m->prev->size);
788 			} else {
789 				m->delta_offset = ftello(delta_cache);
790 				/*
791 				 * TODO:
792 				 * Storing compressed delta data in the delta
793 				 * cache file would probably be more efficient
794 				 * than writing uncompressed delta data here
795 				 * and compressing it while writing the pack
796 				 * file. This would also allow for reusing
797 				 * deltas in their compressed form.
798 				 */
799 				err = encode_delta(m, raw, best_deltas,
800 				    best_ndeltas, m->prev->size, delta_cache);
801 			}
802 			free(best_deltas);
803 			best_deltas = NULL;
804 			best_ndeltas = 0;
805 			if (err)
806 				goto done;
807 		}
808 
809 		got_object_raw_close(raw);
810 		raw = NULL;
811 	}
812 done:
813 	for (i = MAX(0, nmeta - max_base_candidates); i < nmeta; i++) {
814 		got_deltify_free(meta[i]->dtab);
815 		meta[i]->dtab = NULL;
816 	}
817 	if (raw)
818 		got_object_raw_close(raw);
819 	if (base_raw)
820 		got_object_raw_close(base_raw);
821 	if (outfd != -1 && close(outfd) == -1 && err == NULL)
822 		err = got_error_from_errno("close");
823 	free(deltas);
824 	free(best_deltas);
825 	return err;
826 }
827 
828 static const struct got_error *
829 search_packidx(int *found, struct got_object_id *id,
830     struct got_repository *repo)
831 {
832 	const struct got_error *err = NULL;
833 	struct got_packidx *packidx = NULL;
834 	int idx;
835 
836 	*found = 0;
837 
838 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
839 	if (err == NULL)
840 		*found = 1; /* object is already packed */
841 	else if (err->code == GOT_ERR_NO_OBJ)
842 		err = NULL;
843 	return err;
844 }
845 
846 static const struct got_error *
847 add_object(int want_meta, struct got_object_idset *idset,
848     struct got_object_id *id, const char *path, int obj_type,
849     time_t mtime, int loose_obj_only, struct got_repository *repo,
850     int *ncolored, int *nfound, int *ntrees,
851     got_pack_progress_cb progress_cb, void *progress_arg,
852     struct got_ratelimit *rl)
853 {
854 	const struct got_error *err;
855 	struct got_pack_meta *m = NULL;
856 
857 	if (loose_obj_only) {
858 		int is_packed;
859 		err = search_packidx(&is_packed, id, repo);
860 		if (err)
861 			return err;
862 		if (is_packed && want_meta)
863 			return NULL;
864 	}
865 
866 	if (want_meta) {
867 		err = alloc_meta(&m, id, path, obj_type, mtime);
868 		if (err)
869 			return err;
870 
871 		(*nfound)++;
872 		err = report_progress(progress_cb, progress_arg, rl,
873 		    *ncolored, *nfound, *ntrees, 0L, 0, 0, 0, 0);
874 		if (err) {
875 			clear_meta(m);
876 			free(m);
877 			return err;
878 		}
879 	}
880 
881 	err = got_object_idset_add(idset, id, m);
882 	if (err) {
883 		clear_meta(m);
884 		free(m);
885 	}
886 	return err;
887 }
888 
889 static const struct got_error *
890 load_tree_entries(struct got_object_id_queue *ids, int want_meta,
891     struct got_object_idset *idset, struct got_object_id *tree_id,
892     const char *dpath, time_t mtime, struct got_repository *repo,
893     int loose_obj_only, int *ncolored, int *nfound, int *ntrees,
894     got_pack_progress_cb progress_cb, void *progress_arg,
895     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
896 {
897 	const struct got_error *err;
898 	struct got_tree_object *tree;
899 	char *p = NULL;
900 	int i;
901 
902 	err = got_object_open_as_tree(&tree, repo, tree_id);
903 	if (err)
904 		return err;
905 
906 	(*ntrees)++;
907 	err = report_progress(progress_cb, progress_arg, rl,
908 	    *ncolored, *nfound, *ntrees, 0L, 0, 0, 0, 0);
909 	if (err)
910 		return err;
911 
912 	for (i = 0; i < got_object_tree_get_nentries(tree); i++) {
913 		struct got_tree_entry *e = got_object_tree_get_entry(tree, i);
914 		struct got_object_id *id = got_tree_entry_get_id(e);
915 		mode_t mode = got_tree_entry_get_mode(e);
916 
917 		if (cancel_cb) {
918 			err = (*cancel_cb)(cancel_arg);
919 			if (err)
920 				break;
921 		}
922 
923 		if (got_object_tree_entry_is_submodule(e) ||
924 		    got_object_idset_contains(idset, id))
925 			continue;
926 		
927 		if (asprintf(&p, "%s%s%s", dpath, dpath[0] != '\0' ? "/" : "",
928 		    got_tree_entry_get_name(e)) == -1) {
929 			err = got_error_from_errno("asprintf");
930 			break;
931 		}
932 
933 		if (S_ISDIR(mode)) {
934 			struct got_object_qid *qid;
935 			err = got_object_qid_alloc(&qid, id);
936 			if (err)
937 				break;
938 			STAILQ_INSERT_TAIL(ids, qid, entry);
939 		} else if (S_ISREG(mode) || S_ISLNK(mode)) {
940 			err = add_object(want_meta, idset, id, p,
941 			    GOT_OBJ_TYPE_BLOB, mtime, loose_obj_only, repo,
942 			    ncolored, nfound, ntrees,
943 			    progress_cb, progress_arg, rl);
944 			if (err)
945 				break;
946 		}
947 		free(p);
948 		p = NULL;
949 	}
950 
951 	got_object_tree_close(tree);
952 	free(p);
953 	return err;
954 }
955 
956 static const struct got_error *
957 load_tree(int want_meta, struct got_object_idset *idset,
958     struct got_object_id *tree_id, const char *dpath, time_t mtime,
959     struct got_repository *repo, int loose_obj_only,
960     int *ncolored, int *nfound, int *ntrees,
961     got_pack_progress_cb progress_cb, void *progress_arg,
962     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
963 {
964 	const struct got_error *err = NULL;
965 	struct got_object_id_queue tree_ids;
966 	struct got_object_qid *qid;
967 
968 	if (got_object_idset_contains(idset, tree_id))
969 		return NULL;
970 
971 	err = got_object_qid_alloc(&qid, tree_id);
972 	if (err)
973 		return err;
974 
975 	STAILQ_INIT(&tree_ids);
976 	STAILQ_INSERT_TAIL(&tree_ids, qid, entry);
977 
978 	while (!STAILQ_EMPTY(&tree_ids)) {
979 		if (cancel_cb) {
980 			err = (*cancel_cb)(cancel_arg);
981 			if (err)
982 				break;
983 		}
984 
985 		qid = STAILQ_FIRST(&tree_ids);
986 		STAILQ_REMOVE_HEAD(&tree_ids, entry);
987 
988 		if (got_object_idset_contains(idset, &qid->id)) {
989 			got_object_qid_free(qid);
990 			continue;
991 		}
992 
993 		err = add_object(want_meta, idset, &qid->id, dpath,
994 		    GOT_OBJ_TYPE_TREE, mtime, loose_obj_only, repo,
995 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
996 		if (err) {
997 			got_object_qid_free(qid);
998 			break;
999 		}
1000 
1001 		err = load_tree_entries(&tree_ids, want_meta, idset, &qid->id,
1002 		    dpath, mtime, repo, loose_obj_only, ncolored, nfound,
1003 		    ntrees, progress_cb, progress_arg, rl,
1004 		    cancel_cb, cancel_arg);
1005 		got_object_qid_free(qid);
1006 		if (err)
1007 			break;
1008 	}
1009 
1010 	got_object_id_queue_free(&tree_ids);
1011 	return err;
1012 }
1013 
1014 static const struct got_error *
1015 load_commit(int want_meta, struct got_object_idset *idset,
1016     struct got_object_id *id, struct got_repository *repo, int loose_obj_only,
1017     int *ncolored, int *nfound, int *ntrees,
1018     got_pack_progress_cb progress_cb, void *progress_arg,
1019     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1020 {
1021 	const struct got_error *err;
1022 	struct got_commit_object *commit;
1023 
1024 	if (got_object_idset_contains(idset, id))
1025 		return NULL;
1026 
1027 	if (loose_obj_only) {
1028 		int is_packed;
1029 		err = search_packidx(&is_packed, id, repo);
1030 		if (err)
1031 			return err;
1032 		if (is_packed && want_meta)
1033 			return NULL;
1034 	}
1035 
1036 	err = got_object_open_as_commit(&commit, repo, id);
1037 	if (err)
1038 		return err;
1039 
1040 	err = add_object(want_meta, idset, id, "", GOT_OBJ_TYPE_COMMIT,
1041 	    got_object_commit_get_committer_time(commit),
1042 	    loose_obj_only, repo,
1043 	    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
1044 	if (err)
1045 		goto done;
1046 
1047 	err = load_tree(want_meta, idset, got_object_commit_get_tree_id(commit),
1048 	    "", got_object_commit_get_committer_time(commit),
1049 	    repo, loose_obj_only, ncolored, nfound, ntrees,
1050 	    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
1051 done:
1052 	got_object_commit_close(commit);
1053 	return err;
1054 }
1055 
1056 static const struct got_error *
1057 load_tag(int want_meta, struct got_object_idset *idset,
1058     struct got_object_id *id, struct got_repository *repo, int loose_obj_only,
1059     int *ncolored, int *nfound, int *ntrees,
1060     got_pack_progress_cb progress_cb, void *progress_arg,
1061     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1062 {
1063 	const struct got_error *err;
1064 	struct got_tag_object *tag = NULL;
1065 
1066 	if (got_object_idset_contains(idset, id))
1067 		return NULL;
1068 
1069 	if (loose_obj_only) {
1070 		int is_packed;
1071 		err = search_packidx(&is_packed, id, repo);
1072 		if (err)
1073 			return err;
1074 		if (is_packed && want_meta)
1075 			return NULL;
1076 	}
1077 
1078 	err = got_object_open_as_tag(&tag, repo, id);
1079 	if (err)
1080 		return err;
1081 
1082 	err = add_object(want_meta, idset, id, "", GOT_OBJ_TYPE_TAG,
1083 	    got_object_tag_get_tagger_time(tag), loose_obj_only, repo,
1084 	    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
1085 	if (err)
1086 		goto done;
1087 
1088 	switch (got_object_tag_get_object_type(tag)) {
1089 	case GOT_OBJ_TYPE_COMMIT:
1090 		err = load_commit(want_meta, idset,
1091 		    got_object_tag_get_object_id(tag), repo, loose_obj_only,
1092 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl,
1093 		    cancel_cb, cancel_arg);
1094 		break;
1095 	case GOT_OBJ_TYPE_TREE:
1096 		err = load_tree(want_meta, idset,
1097 		    got_object_tag_get_object_id(tag), "",
1098 		    got_object_tag_get_tagger_time(tag), repo, loose_obj_only,
1099 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl,
1100 		    cancel_cb, cancel_arg);
1101 		break;
1102 	default:
1103 		break;
1104 	}
1105 
1106 done:
1107 	got_object_tag_close(tag);
1108 	return err;
1109 }
1110 
1111 enum findtwixt_color {
1112 	COLOR_KEEP = 0,
1113 	COLOR_DROP,
1114 	COLOR_BLANK,
1115 	COLOR_SKIP,
1116 };
1117 
1118 static const int findtwixt_colors[] = {
1119 	COLOR_KEEP,
1120 	COLOR_DROP,
1121 	COLOR_BLANK,
1122 	COLOR_SKIP,
1123 };
1124 
1125 static const struct got_error *
1126 paint_commit(struct got_object_qid *qid, int color)
1127 {
1128 	if (color < 0 || color >= nitems(findtwixt_colors))
1129 		return got_error(GOT_ERR_RANGE);
1130 
1131 	qid->data = (void *)&findtwixt_colors[color];
1132 	return NULL;
1133 }
1134 
1135 static const struct got_error *
1136 queue_commit_id(struct got_object_id_queue *ids, struct got_object_id *id,
1137     int color, struct got_repository *repo)
1138 {
1139 	const struct got_error *err;
1140 	struct got_object_qid *qid;
1141 
1142 	err = got_object_qid_alloc(&qid, id);
1143 	if (err)
1144 		return err;
1145 
1146 	STAILQ_INSERT_TAIL(ids, qid, entry);
1147 	return paint_commit(qid, color);
1148 }
1149 
1150 struct append_id_arg {
1151 	struct got_object_id **array;
1152 	int idx;
1153 	struct got_object_idset *drop;
1154 	struct got_object_idset *skip;
1155 };
1156 
1157 static const struct got_error *
1158 append_id(struct got_object_id *id, void *data, void *arg)
1159 {
1160 	struct append_id_arg *a = arg;
1161 
1162 	if (got_object_idset_contains(a->skip, id) ||
1163 	    got_object_idset_contains(a->drop, id))
1164 		return NULL;
1165 
1166 	a->array[++a->idx] = got_object_id_dup(id);
1167 	if (a->array[a->idx] == NULL)
1168 		return got_error_from_errno("got_object_id_dup");
1169 
1170 	return NULL;
1171 }
1172 
1173 static const struct got_error *
1174 queue_commit_or_tag_id(struct got_object_id *id, int color,
1175     struct got_object_id_queue *ids, struct got_repository *repo)
1176 {
1177 	const struct got_error *err;
1178 	struct got_tag_object *tag = NULL;
1179 	int obj_type;
1180 
1181 	err = got_object_get_type(&obj_type, repo, id);
1182 	if (err)
1183 		return err;
1184 
1185 	if (obj_type == GOT_OBJ_TYPE_TAG) {
1186 		err = got_object_open_as_tag(&tag, repo, id);
1187 		if (err)
1188 			return err;
1189 		obj_type = got_object_tag_get_object_type(tag);
1190 		id = got_object_tag_get_object_id(tag);
1191 	}
1192 
1193 	if (obj_type == GOT_OBJ_TYPE_COMMIT) {
1194 		err = queue_commit_id(ids, id, color, repo);
1195 		if (err)
1196 			goto done;
1197 	}
1198 done:
1199 	if (tag)
1200 		got_object_tag_close(tag);
1201 	return err;
1202 }
1203 
1204 static const struct got_error *
1205 paint_commits(int *ncolored, struct got_object_id_queue *ids, int nids,
1206     struct got_object_idset *keep, struct got_object_idset *drop,
1207     struct got_object_idset *skip, struct got_repository *repo,
1208     got_pack_progress_cb progress_cb, void *progress_arg,
1209     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1210 {
1211 	const struct got_error *err = NULL;
1212 	struct got_commit_object *commit = NULL;
1213 	const struct got_object_id_queue *parents;
1214 	struct got_object_qid *qid;
1215 	int nqueued = nids, nskip = 0;
1216 
1217 	while (!STAILQ_EMPTY(ids) && nskip != nqueued) {
1218 		int color;
1219 
1220 		if (cancel_cb) {
1221 			err = cancel_cb(cancel_arg);
1222 			if (err)
1223 				break;
1224 		}
1225 
1226 		qid = STAILQ_FIRST(ids);
1227 		STAILQ_REMOVE_HEAD(ids, entry);
1228 		nqueued--;
1229 		color = *((int *)qid->data);
1230 		if (color == COLOR_SKIP)
1231 			nskip--;
1232 
1233 		if (got_object_idset_contains(skip, &qid->id)) {
1234 			got_object_qid_free(qid);
1235 			continue;
1236 		}
1237 
1238 		switch (color) {
1239 		case COLOR_KEEP:
1240 			if (got_object_idset_contains(keep, &qid->id)) {
1241 				got_object_qid_free(qid);
1242 				continue;
1243 			}
1244 			if (got_object_idset_contains(drop, &qid->id)) {
1245 				err = paint_commit(qid, COLOR_SKIP);
1246 				if (err)
1247 					goto done;
1248 				nskip++;
1249 			} else
1250 				(*ncolored)++;
1251 			err = got_object_idset_add(keep, &qid->id, NULL);
1252 			if (err)
1253 				goto done;
1254 			break;
1255 		case COLOR_DROP:
1256 			if (got_object_idset_contains(drop, &qid->id)) {
1257 				got_object_qid_free(qid);
1258 				continue;
1259 			}
1260 			if (got_object_idset_contains(keep, &qid->id)) {
1261 				err = paint_commit(qid, COLOR_SKIP);
1262 				if (err)
1263 					goto done;
1264 				nskip++;
1265 			} else
1266 				(*ncolored)++;
1267 			err = got_object_idset_add(drop, &qid->id, NULL);
1268 			if (err)
1269 				goto done;
1270 			break;
1271 		case COLOR_SKIP:
1272 			if (!got_object_idset_contains(skip, &qid->id)) {
1273 				err = got_object_idset_add(skip, &qid->id,
1274 				    NULL);
1275 				if (err)
1276 					goto done;
1277 			}
1278 			break;
1279 		default:
1280 			/* should not happen */
1281 			err = got_error_fmt(GOT_ERR_NOT_IMPL,
1282 			    "%s invalid commit color %d", __func__, color);
1283 			goto done;
1284 		}
1285 
1286 		err = report_progress(progress_cb, progress_arg, rl,
1287 		    *ncolored, 0, 0, 0L, 0, 0, 0, 0);
1288 		if (err)
1289 			break;
1290 
1291 
1292 		err = got_object_open_as_commit(&commit, repo, &qid->id);
1293 		if (err)
1294 			break;
1295 
1296 		parents = got_object_commit_get_parent_ids(commit);
1297 		if (parents) {
1298 			struct got_object_qid *pid;
1299 			color = *((int *)qid->data);
1300 			STAILQ_FOREACH(pid, parents, entry) {
1301 				err = queue_commit_id(ids, &pid->id, color,
1302 				    repo);
1303 				if (err)
1304 					break;
1305 				nqueued++;
1306 				if (color == COLOR_SKIP)
1307 					nskip++;
1308 			}
1309 		}
1310 
1311 		got_object_commit_close(commit);
1312 		commit = NULL;
1313 		got_object_qid_free(qid);
1314 	}
1315 done:
1316 	if (commit)
1317 		got_object_commit_close(commit);
1318 	return err;
1319 }
1320 
1321 static const struct got_error *
1322 findtwixt(struct got_object_id ***res, int *nres, int *ncolored,
1323     struct got_object_id **head, int nhead,
1324     struct got_object_id **tail, int ntail,
1325     struct got_repository *repo,
1326     got_pack_progress_cb progress_cb, void *progress_arg,
1327     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1328 {
1329 	const struct got_error *err = NULL;
1330 	struct got_object_id_queue ids;
1331 	struct got_object_idset *keep, *drop, *skip = NULL;
1332 	int i, nkeep;
1333 
1334 	STAILQ_INIT(&ids);
1335 	*res = NULL;
1336 	*nres = 0;
1337 	*ncolored = 0;
1338 
1339 	keep = got_object_idset_alloc();
1340 	if (keep == NULL)
1341 		return got_error_from_errno("got_object_idset_alloc");
1342 
1343 	drop = got_object_idset_alloc();
1344 	if (drop == NULL) {
1345 		err = got_error_from_errno("got_object_idset_alloc");
1346 		goto done;
1347 	}
1348 
1349 	skip = got_object_idset_alloc();
1350 	if (skip == NULL) {
1351 		err = got_error_from_errno("got_object_idset_alloc");
1352 		goto done;
1353 	}
1354 
1355 	for (i = 0; i < nhead; i++) {
1356 		struct got_object_id *id = head[i];
1357 		if (id == NULL)
1358 			continue;
1359 		err = queue_commit_or_tag_id(id, COLOR_KEEP, &ids, repo);
1360 		if (err)
1361 			goto done;
1362 	}		
1363 
1364 	for (i = 0; i < ntail; i++) {
1365 		struct got_object_id *id = tail[i];
1366 		if (id == NULL)
1367 			continue;
1368 		err = queue_commit_or_tag_id(id, COLOR_DROP, &ids, repo);
1369 		if (err)
1370 			goto done;
1371 	}
1372 
1373 	err = paint_commits(ncolored, &ids, nhead + ntail,
1374 	    keep, drop, skip, repo, progress_cb, progress_arg, rl,
1375 	    cancel_cb, cancel_arg);
1376 	if (err)
1377 		goto done;
1378 
1379 	nkeep = got_object_idset_num_elements(keep);
1380 	if (nkeep > 0) {
1381 		struct append_id_arg arg;
1382 		arg.array = calloc(nkeep, sizeof(struct got_object_id *));
1383 		if (arg.array == NULL) {
1384 			err = got_error_from_errno("calloc");
1385 			goto done;
1386 		}
1387 		arg.idx = -1;
1388 		arg.skip = skip;
1389 		arg.drop = drop;
1390 		err = got_object_idset_for_each(keep, append_id, &arg);
1391 		if (err) {
1392 			free(arg.array);
1393 			goto done;
1394 		}
1395 		*res = arg.array;
1396 		*nres = arg.idx + 1;
1397 	}
1398 done:
1399 	got_object_idset_free(keep);
1400 	got_object_idset_free(drop);
1401 	if (skip)
1402 		got_object_idset_free(skip);
1403 	got_object_id_queue_free(&ids);
1404 	return err;
1405 }
1406 
1407 static const struct got_error *
1408 load_object_ids(int *ncolored, int *nfound, int *ntrees,
1409     struct got_object_idset *idset, struct got_object_id **theirs, int ntheirs,
1410     struct got_object_id **ours, int nours, struct got_repository *repo,
1411     int loose_obj_only, got_pack_progress_cb progress_cb, void *progress_arg,
1412     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1413 {
1414 	const struct got_error *err = NULL;
1415 	struct got_object_id **ids = NULL;
1416 	int i, nobj = 0, obj_type;
1417 
1418 	*ncolored = 0;
1419 	*nfound = 0;
1420 	*ntrees = 0;
1421 
1422 	err = findtwixt(&ids, &nobj, ncolored, ours, nours, theirs, ntheirs,
1423 	    repo, progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
1424 	if (err || nobj == 0)
1425 		goto done;
1426 
1427 	for (i = 0; i < ntheirs; i++) {
1428 		struct got_object_id *id = theirs[i];
1429 		if (id == NULL)
1430 			continue;
1431 		err = got_object_get_type(&obj_type, repo, id);
1432 		if (err)
1433 			return err;
1434 		if (obj_type == GOT_OBJ_TYPE_COMMIT) {
1435 			err = load_commit(0, idset, id, repo,
1436 			    loose_obj_only, ncolored, nfound, ntrees,
1437 			    progress_cb, progress_arg, rl,
1438 			    cancel_cb, cancel_arg);
1439 			if (err)
1440 				goto done;
1441 		} else if (obj_type == GOT_OBJ_TYPE_TAG) {
1442 			err = load_tag(0, idset, id, repo,
1443 			    loose_obj_only, ncolored, nfound, ntrees,
1444 			    progress_cb, progress_arg, rl,
1445 			    cancel_cb, cancel_arg);
1446 			if (err)
1447 				goto done;
1448 		}
1449 	}
1450 
1451 	for (i = 0; i < nobj; i++) {
1452 		err = load_commit(1, idset, ids[i], repo, loose_obj_only,
1453 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl,
1454 		    cancel_cb, cancel_arg);
1455 		if (err)
1456 			goto done;
1457 	}
1458 
1459 	for (i = 0; i < nours; i++) {
1460 		struct got_object_id *id = ours[i];
1461 		struct got_pack_meta *m;
1462 		if (id == NULL)
1463 			continue;
1464 		m = got_object_idset_get(idset, id);
1465 		if (m == NULL) {
1466 			err = got_object_get_type(&obj_type, repo, id);
1467 			if (err)
1468 				goto done;
1469 		} else
1470 			obj_type = m->obj_type;
1471 		if (obj_type != GOT_OBJ_TYPE_TAG)
1472 			continue;
1473 		err = load_tag(1, idset, id, repo, loose_obj_only,
1474 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl,
1475 		    cancel_cb, cancel_arg);
1476 		if (err)
1477 			goto done;
1478 	}
1479 done:
1480 	for (i = 0; i < nobj; i++) {
1481 		free(ids[i]);
1482 	}
1483 	free(ids);
1484 	return err;
1485 }
1486 
1487 const struct got_error *
1488 hwrite(FILE *f, void *buf, int len, SHA1_CTX *ctx)
1489 {
1490 	size_t n;
1491 
1492 	SHA1Update(ctx, buf, len);
1493 	n = fwrite(buf, 1, len, f);
1494 	if (n != len)
1495 		return got_ferror(f, GOT_ERR_IO);
1496 	return NULL;
1497 }
1498 
1499 static void
1500 putbe32(char *b, uint32_t n)
1501 {
1502 	b[0] = n >> 24;
1503 	b[1] = n >> 16;
1504 	b[2] = n >> 8;
1505 	b[3] = n >> 0;
1506 }
1507 
1508 static int
1509 write_order_cmp(const void *pa, const void *pb)
1510 {
1511 	struct got_pack_meta *a, *b, *ahd, *bhd;
1512 
1513 	a = *(struct got_pack_meta **)pa;
1514 	b = *(struct got_pack_meta **)pb;
1515 	ahd = (a->head == NULL) ? a : a->head;
1516 	bhd = (b->head == NULL) ? b : b->head;
1517 	if (ahd->mtime != bhd->mtime)
1518 		return bhd->mtime - ahd->mtime;
1519 	if (ahd != bhd)
1520 		return (uintptr_t)bhd - (uintptr_t)ahd;
1521 	if (a->nchain != b->nchain)
1522 		return a->nchain - b->nchain;
1523 	return a->mtime - b->mtime;
1524 }
1525 
1526 static int
1527 reuse_write_order_cmp(const void *pa, const void *pb)
1528 {
1529 	struct got_pack_meta *a, *b;
1530 
1531 	a = *(struct got_pack_meta **)pa;
1532 	b = *(struct got_pack_meta **)pb;
1533 
1534 	if (a->reused_delta_offset < b->reused_delta_offset)
1535 		return -1;
1536 	if (a->reused_delta_offset > b->reused_delta_offset)
1537 		return 1;
1538 	return 0;
1539 }
1540 
1541 static const struct got_error *
1542 packhdr(int *hdrlen, char *hdr, size_t bufsize, int obj_type, size_t len)
1543 {
1544 	size_t i;
1545 
1546 	*hdrlen = 0;
1547 
1548 	hdr[0] = obj_type << 4;
1549 	hdr[0] |= len & 0xf;
1550 	len >>= 4;
1551 	for (i = 1; len != 0; i++){
1552 		if (i >= bufsize)
1553 			return got_error(GOT_ERR_NO_SPACE);
1554 		hdr[i - 1] |= GOT_DELTA_SIZE_MORE;
1555 		hdr[i] = len & GOT_DELTA_SIZE_VAL_MASK;
1556 		len >>= GOT_DELTA_SIZE_SHIFT;
1557 	}
1558 
1559 	*hdrlen = i;
1560 	return NULL;
1561 }
1562 
1563 static int
1564 packoff(char *hdr, off_t off)
1565 {
1566 	int i, j;
1567 	char rbuf[8];
1568 
1569 	rbuf[0] = off & GOT_DELTA_SIZE_VAL_MASK;
1570 	for (i = 1; (off >>= GOT_DELTA_SIZE_SHIFT) != 0; i++) {
1571 		rbuf[i] = (--off & GOT_DELTA_SIZE_VAL_MASK) |
1572 		    GOT_DELTA_SIZE_MORE;
1573 	}
1574 
1575 	j = 0;
1576 	while (i > 0)
1577 		hdr[j++] = rbuf[--i];
1578 	return j;
1579 }
1580 
1581 static const struct got_error *
1582 deltahdr(off_t *packfile_size, SHA1_CTX *ctx, FILE *packfile,
1583     struct got_pack_meta *m)
1584 {
1585 	const struct got_error *err;
1586 	char buf[32];
1587 	int nh;
1588 
1589 	if (m->prev->off != 0) {
1590 		err = packhdr(&nh, buf, sizeof(buf),
1591 		    GOT_OBJ_TYPE_OFFSET_DELTA, m->delta_len);
1592 		if (err)
1593 			return err;
1594 		nh += packoff(buf + nh, m->off - m->prev->off);
1595 		err = hwrite(packfile, buf, nh, ctx);
1596 		if (err)
1597 			return err;
1598 		*packfile_size += nh;
1599 	} else {
1600 		err = packhdr(&nh, buf, sizeof(buf),
1601 		    GOT_OBJ_TYPE_REF_DELTA, m->delta_len);
1602 		if (err)
1603 			return err;
1604 		err = hwrite(packfile, buf, nh, ctx);
1605 		if (err)
1606 			return err;
1607 		*packfile_size += nh;
1608 		err = hwrite(packfile, m->prev->id.sha1,
1609 		    sizeof(m->prev->id.sha1), ctx);
1610 		if (err)
1611 			return err;
1612 		*packfile_size += sizeof(m->prev->id.sha1);
1613 	}
1614 
1615 	return NULL;
1616 }
1617 
1618 static const struct got_error *
1619 write_packed_object(off_t *packfile_size, FILE *packfile,
1620     FILE *delta_cache, struct got_pack_meta *m, int *outfd,
1621     SHA1_CTX *ctx, struct got_repository *repo)
1622 {
1623 	const struct got_error *err = NULL;
1624 	struct got_deflate_checksum csum;
1625 	char buf[32];
1626 	int nh;
1627 	struct got_raw_object *raw = NULL;
1628 	off_t outlen;
1629 
1630 	csum.output_sha1 = ctx;
1631 	csum.output_crc = NULL;
1632 
1633 	m->off = ftello(packfile);
1634 	if (m->delta_len == 0) {
1635 		err = got_object_raw_open(&raw, outfd, repo, &m->id);
1636 		if (err)
1637 			goto done;
1638 		err = packhdr(&nh, buf, sizeof(buf),
1639 		    m->obj_type, raw->size);
1640 		if (err)
1641 			goto done;
1642 		err = hwrite(packfile, buf, nh, ctx);
1643 		if (err)
1644 			goto done;
1645 		*packfile_size += nh;
1646 		if (raw->f == NULL) {
1647 			err = got_deflate_to_file_mmap(&outlen,
1648 			    raw->data + raw->hdrlen, 0, raw->size,
1649 			    packfile, &csum);
1650 			if (err)
1651 				goto done;
1652 		} else {
1653 			if (fseeko(raw->f, raw->hdrlen, SEEK_SET)
1654 			    == -1) {
1655 				err = got_error_from_errno("fseeko");
1656 				goto done;
1657 			}
1658 			err = got_deflate_to_file(&outlen, raw->f,
1659 			    raw->size, packfile, &csum);
1660 			if (err)
1661 				goto done;
1662 		}
1663 		*packfile_size += outlen;
1664 		got_object_raw_close(raw);
1665 		raw = NULL;
1666 	} else if (m->delta_buf) {
1667 		err = deltahdr(packfile_size, ctx, packfile, m);
1668 		if (err)
1669 			goto done;
1670 		err = got_deflate_to_file_mmap(&outlen,
1671 		    m->delta_buf, 0, m->delta_len, packfile, &csum);
1672 		if (err)
1673 			goto done;
1674 		*packfile_size += outlen;
1675 		free(m->delta_buf);
1676 		m->delta_buf = NULL;
1677 	} else {
1678 		if (fseeko(delta_cache, m->delta_offset, SEEK_SET)
1679 		    == -1) {
1680 			err = got_error_from_errno("fseeko");
1681 			goto done;
1682 		}
1683 		err = deltahdr(packfile_size, ctx, packfile, m);
1684 		if (err)
1685 			goto done;
1686 		err = got_deflate_to_file(&outlen, delta_cache,
1687 		    m->delta_len, packfile, &csum);
1688 		if (err)
1689 			goto done;
1690 		*packfile_size += outlen;
1691 	}
1692 done:
1693 	if (raw)
1694 		got_object_raw_close(raw);
1695 	return err;
1696 }
1697 
1698 static const struct got_error *
1699 genpack(uint8_t *pack_sha1, FILE *packfile, FILE *delta_cache,
1700     struct got_pack_meta **deltify, int ndeltify,
1701     struct got_pack_meta **reuse, int nreuse,
1702     int ncolored, int nfound, int ntrees, int nours,
1703     struct got_repository *repo,
1704     got_pack_progress_cb progress_cb, void *progress_arg,
1705     struct got_ratelimit *rl,
1706     got_cancel_cb cancel_cb, void *cancel_arg)
1707 {
1708 	const struct got_error *err = NULL;
1709 	int i;
1710 	SHA1_CTX ctx;
1711 	struct got_pack_meta *m;
1712 	char buf[32];
1713 	size_t n;
1714 	off_t packfile_size = 0;
1715 	int outfd = -1;
1716 
1717 	SHA1Init(&ctx);
1718 
1719 	err = hwrite(packfile, "PACK", 4, &ctx);
1720 	if (err)
1721 		return err;
1722 	putbe32(buf, GOT_PACKFILE_VERSION);
1723 	err = hwrite(packfile, buf, 4, &ctx);
1724 	if (err)
1725 		goto done;
1726 	putbe32(buf, ndeltify + nreuse);
1727 	err = hwrite(packfile, buf, 4, &ctx);
1728 	if (err)
1729 		goto done;
1730 
1731 	qsort(deltify, ndeltify, sizeof(struct got_pack_meta *),
1732 	    write_order_cmp);
1733 	for (i = 0; i < ndeltify; i++) {
1734 		err = report_progress(progress_cb, progress_arg, rl,
1735 		    ncolored, nfound, ntrees, packfile_size, nours,
1736 		    ndeltify + nreuse, ndeltify + nreuse, i);
1737 		if (err)
1738 			goto done;
1739 		m = deltify[i];
1740 		err = write_packed_object(&packfile_size, packfile,
1741 		    delta_cache, m, &outfd, &ctx, repo);
1742 		if (err)
1743 			goto done;
1744 	}
1745 
1746 	qsort(reuse, nreuse, sizeof(struct got_pack_meta *),
1747 	    reuse_write_order_cmp);
1748 	for (i = 0; i < nreuse; i++) {
1749 		err = report_progress(progress_cb, progress_arg, rl,
1750 		    ncolored, nfound, ntrees, packfile_size, nours,
1751 		    ndeltify + nreuse, ndeltify + nreuse, ndeltify + i);
1752 		if (err)
1753 			goto done;
1754 		m = reuse[i];
1755 		err = write_packed_object(&packfile_size, packfile,
1756 		    delta_cache, m, &outfd, &ctx, repo);
1757 		if (err)
1758 			goto done;
1759 	}
1760 
1761 	SHA1Final(pack_sha1, &ctx);
1762 	n = fwrite(pack_sha1, 1, SHA1_DIGEST_LENGTH, packfile);
1763 	if (n != SHA1_DIGEST_LENGTH)
1764 		err = got_ferror(packfile, GOT_ERR_IO);
1765 	packfile_size += SHA1_DIGEST_LENGTH;
1766 	packfile_size += sizeof(struct got_packfile_hdr);
1767 	if (progress_cb) {
1768 		err = progress_cb(progress_arg, ncolored, nfound, ntrees,
1769 		    packfile_size, nours, ndeltify + nreuse,
1770 		    ndeltify + nreuse, ndeltify + nreuse);
1771 		if (err)
1772 			goto done;
1773 	}
1774 done:
1775 	if (outfd != -1 && close(outfd) == -1 && err == NULL)
1776 		err = got_error_from_errno("close");
1777 	return err;
1778 }
1779 
1780 static const struct got_error *
1781 remove_unused_object(struct got_object_id *id, void *data, void *arg)
1782 {
1783 	struct got_object_idset *idset = arg;
1784 
1785 	if (data == NULL)
1786 		got_object_idset_remove(NULL, idset, id);
1787 
1788 	return NULL;
1789 }
1790 
1791 static const struct got_error *
1792 remove_reused_object(struct got_object_id *id, void *data, void *arg)
1793 {
1794 	struct got_object_idset *idset = arg;
1795 	struct got_pack_meta *m = data;
1796 
1797 	if (m->have_reused_delta)
1798 		got_object_idset_remove(NULL, idset, id);
1799 
1800 	return NULL;
1801 }
1802 
1803 static const struct got_error *
1804 add_meta_idset_cb(struct got_object_id *id, void *data, void *arg)
1805 {
1806 	struct got_pack_meta *m = data;
1807 	struct got_pack_metavec *v = arg;
1808 
1809 	return add_meta(m, v);
1810 }
1811 
1812 const struct got_error *
1813 got_pack_create(uint8_t *packsha1, FILE *packfile,
1814     struct got_object_id **theirs, int ntheirs,
1815     struct got_object_id **ours, int nours,
1816     struct got_repository *repo, int loose_obj_only, int allow_empty,
1817     got_pack_progress_cb progress_cb, void *progress_arg,
1818     got_cancel_cb cancel_cb, void *cancel_arg)
1819 {
1820 	const struct got_error *err;
1821 	int delta_cache_fd = -1;
1822 	FILE *delta_cache = NULL;
1823 	struct got_object_idset *idset;
1824 	struct got_ratelimit rl;
1825 	struct got_pack_metavec deltify, reuse;
1826 	int ncolored = 0, nfound = 0, ntrees = 0;
1827 
1828 	memset(&deltify, 0, sizeof(deltify));
1829 	memset(&reuse, 0, sizeof(reuse));
1830 
1831 	got_ratelimit_init(&rl, 0, 500);
1832 
1833 	idset = got_object_idset_alloc();
1834 	if (idset == NULL)
1835 		return got_error_from_errno("got_object_idset_alloc");
1836 
1837 	err = load_object_ids(&ncolored, &nfound, &ntrees, idset, theirs,
1838 	    ntheirs, ours, nours, repo, loose_obj_only,
1839 	    progress_cb, progress_arg, &rl, cancel_cb, cancel_arg);
1840 	if (err)
1841 		return err;
1842 
1843 	err = got_object_idset_for_each(idset, remove_unused_object, idset);
1844 	if (err)
1845 		goto done;
1846 
1847 	if (progress_cb) {
1848 		err = progress_cb(progress_arg, ncolored, nfound, ntrees,
1849 		    0L, nours, got_object_idset_num_elements(idset), 0, 0);
1850 		if (err)
1851 			goto done;
1852 	}
1853 
1854 	if (got_object_idset_num_elements(idset) == 0 && !allow_empty) {
1855 		err = got_error(GOT_ERR_CANNOT_PACK);
1856 		goto done;
1857 	}
1858 
1859 	delta_cache_fd = got_opentempfd();
1860 	if (delta_cache_fd == -1) {
1861 		err = got_error_from_errno("got_opentemp");
1862 		goto done;
1863 	}
1864 
1865 	reuse.metasz = 64;
1866 	reuse.meta = calloc(reuse.metasz,
1867 	    sizeof(struct got_pack_meta *));
1868 	if (reuse.meta == NULL) {
1869 		err = got_error_from_errno("calloc");
1870 		goto done;
1871 	}
1872 
1873 	err = search_deltas(&reuse, idset, delta_cache_fd, ncolored, nfound,
1874 	    ntrees, nours, repo, progress_cb, progress_arg, &rl,
1875 	    cancel_cb, cancel_arg);
1876 	if (err)
1877 		goto done;
1878 	if (reuse.nmeta > 0) {
1879 		err = got_object_idset_for_each(idset,
1880 		    remove_reused_object, idset);
1881 		if (err)
1882 			goto done;
1883 	}
1884 
1885 	delta_cache = fdopen(delta_cache_fd, "a+");
1886 	if (delta_cache == NULL) {
1887 		err = got_error_from_errno("fdopen");
1888 		goto done;
1889 	}
1890 	delta_cache_fd = -1;
1891 
1892 	if (fseeko(delta_cache, 0L, SEEK_END) == -1) {
1893 		err = got_error_from_errno("fseeko");
1894 		goto done;
1895 	}
1896 
1897 	deltify.meta = calloc(got_object_idset_num_elements(idset),
1898 	    sizeof(struct got_pack_meta *));
1899 	if (deltify.meta == NULL) {
1900 		err = got_error_from_errno("calloc");
1901 		goto done;
1902 	}
1903 	deltify.metasz = got_object_idset_num_elements(idset);
1904 
1905 	err = got_object_idset_for_each(idset, add_meta_idset_cb, &deltify);
1906 	if (err)
1907 		goto done;
1908 	if (deltify.nmeta > 0) {
1909 		err = pick_deltas(deltify.meta, deltify.nmeta, ncolored,
1910 		    nfound, ntrees, nours, reuse.nmeta, delta_cache, repo,
1911 		    progress_cb, progress_arg, &rl, cancel_cb, cancel_arg);
1912 		if (err)
1913 			goto done;
1914 		if (fseeko(delta_cache, 0L, SEEK_SET) == -1) {
1915 			err = got_error_from_errno("fseeko");
1916 			goto done;
1917 		}
1918 	}
1919 
1920 	err = genpack(packsha1, packfile, delta_cache, deltify.meta,
1921 	    deltify.nmeta, reuse.meta, reuse.nmeta, ncolored, nfound, ntrees,
1922 	    nours, repo, progress_cb, progress_arg, &rl,
1923 	    cancel_cb, cancel_arg);
1924 	if (err)
1925 		goto done;
1926 done:
1927 	free_nmeta(deltify.meta, deltify.nmeta);
1928 	free_nmeta(reuse.meta, reuse.nmeta);
1929 	got_object_idset_free(idset);
1930 	if (delta_cache_fd != -1 && close(delta_cache_fd) == -1 && err == NULL)
1931 		err = got_error_from_errno("close");
1932 	if (delta_cache && fclose(delta_cache) == EOF && err == NULL)
1933 		err = got_error_from_errno("fclose");
1934 	return err;
1935 }