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Date:: Sun Oct 10 19:26:26 2021 UTC
Message:: speed up 'got histedit -l' and 'got rebase -l' Cache commit timestamps in struct got_reference in case we are sorting references by commit timestamp. This avoids opening and closing commits every time we compare two references with each other. ok thomas.adam
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1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/queue.h>
19 #include <sys/stat.h>
20 
21 #include <errno.h>
22 #include <ctype.h>
23 #include <dirent.h>
24 #include <limits.h>
25 #include <sha1.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30 #include <util.h>
31 #include <zlib.h>
32 #include <time.h>
33 #include <libgen.h>
34 
35 #include "got_error.h"
36 #include "got_object.h"
37 #include "got_repository.h"
38 #include "got_reference.h"
39 #include "got_opentemp.h"
40 #include "got_path.h"
41 
42 #include "got_lib_sha1.h"
43 #include "got_lib_delta.h"
44 #include "got_lib_inflate.h"
45 #include "got_lib_object.h"
46 #include "got_lib_object_idset.h"
47 #include "got_lib_lockfile.h"
48 
49 #ifndef nitems
50 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
51 #endif
52 
53 #define GOT_REF_HEADS	"heads"
54 #define GOT_REF_TAGS	"tags"
55 #define GOT_REF_REMOTES	"remotes"
56 
57 /*
58  * We do not resolve tags yet, and don't yet care about sorting refs either,
59  * so packed-refs files we write contain a minimal header which disables all
60  * packed-refs "traits" supported by Git.
61  */
62 #define GOT_PACKED_REFS_HEADER	"# pack-refs with:"
63 
64 /* A symbolic reference. */
65 struct got_symref {
66 	char *name;
67 	char *ref;
68 };
69 
70 #define GOT_REF_RECURSE_MAX	20
71 
72 /* A non-symbolic reference (there is no better designation). */
73 struct got_ref {
74 	char *name;
75 	u_int8_t sha1[SHA1_DIGEST_LENGTH];
76 };
77 
78 /* A reference which points to an arbitrary object. */
79 struct got_reference {
80 	unsigned int flags;
81 #define GOT_REF_IS_SYMBOLIC	0x01
82 #define GOT_REF_IS_PACKED	0x02
83 
84 	union {
85 		struct got_ref ref;
86 		struct got_symref symref;
87 	} ref;
88 
89 	struct got_lockfile *lf;
90 	time_t mtime;
91 
92 	/* Cached timestamp for got_ref_cmp_by_commit_timestamp_descending() */
93 	time_t committer_time;
94 };
95 
96 static const struct got_error *
97 alloc_ref(struct got_reference **ref, const char *name,
98     struct got_object_id *id, int flags, time_t mtime)
99 {
100 	const struct got_error *err = NULL;
101 
102 	*ref = calloc(1, sizeof(**ref));
103 	if (*ref == NULL)
104 		return got_error_from_errno("calloc");
105 
106 	memcpy((*ref)->ref.ref.sha1, id->sha1, sizeof((*ref)->ref.ref.sha1));
107 	(*ref)->flags = flags;
108 	(*ref)->ref.ref.name = strdup(name);
109 	(*ref)->mtime = mtime;
110 	if ((*ref)->ref.ref.name == NULL) {
111 		err = got_error_from_errno("strdup");
112 		got_ref_close(*ref);
113 		*ref = NULL;
114 	}
115 	return err;
116 }
117 
118 static const struct got_error *
119 alloc_symref(struct got_reference **ref, const char *name,
120     const char *target_ref, int flags)
121 {
122 	const struct got_error *err = NULL;
123 
124 	*ref = calloc(1, sizeof(**ref));
125 	if (*ref == NULL)
126 		return got_error_from_errno("calloc");
127 
128 	(*ref)->flags = GOT_REF_IS_SYMBOLIC | flags;
129 	(*ref)->ref.symref.name = strdup(name);
130 	if ((*ref)->ref.symref.name == NULL) {
131 		err = got_error_from_errno("strdup");
132 		got_ref_close(*ref);
133 		*ref = NULL;
134 		return err;
135 	}
136 	(*ref)->ref.symref.ref = strdup(target_ref);
137 	if ((*ref)->ref.symref.ref == NULL) {
138 		err = got_error_from_errno("strdup");
139 		got_ref_close(*ref);
140 		*ref = NULL;
141 	}
142 	return err;
143 }
144 
145 static const struct got_error *
146 parse_symref(struct got_reference **ref, const char *name, const char *line)
147 {
148 	if (line[0] == '\0')
149 		return got_error(GOT_ERR_BAD_REF_DATA);
150 
151 	return alloc_symref(ref, name, line, 0);
152 }
153 
154 static const struct got_error *
155 parse_ref_line(struct got_reference **ref, const char *name, const char *line,
156     time_t mtime)
157 {
158 	struct got_object_id id;
159 
160 	if (strncmp(line, "ref: ", 5) == 0) {
161 		line += 5;
162 		return parse_symref(ref, name, line);
163 	}
164 
165 	if (!got_parse_sha1_digest(id.sha1, line))
166 		return got_error(GOT_ERR_BAD_REF_DATA);
167 
168 	return alloc_ref(ref, name, &id, 0, mtime);
169 }
170 
171 static const struct got_error *
172 parse_ref_file(struct got_reference **ref, const char *name,
173     const char *absname, const char *abspath, int lock)
174 {
175 	const struct got_error *err = NULL;
176 	FILE *f;
177 	char *line = NULL;
178 	size_t linesize = 0;
179 	ssize_t linelen;
180 	struct got_lockfile *lf = NULL;
181 	struct stat sb;
182 
183 	if (lock) {
184 		err = got_lockfile_lock(&lf, abspath, -1);
185 		if (err) {
186 			if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
187 				err = got_error_not_ref(name);
188 			return err;
189 		}
190 	}
191 
192 	f = fopen(abspath, "rb");
193 	if (f == NULL) {
194 		if (errno != ENOTDIR && errno != ENOENT)
195 			err = got_error_from_errno2("fopen", abspath);
196 		else
197 			err = got_error_not_ref(name);
198 		if (lock)
199 			got_lockfile_unlock(lf, -1);
200 		return err;
201 	}
202 	if (fstat(fileno(f), &sb) == -1) {
203 		err = got_error_from_errno2("fstat", abspath);
204 		goto done;
205 	}
206 
207 	linelen = getline(&line, &linesize, f);
208 	if (linelen == -1) {
209 		if (feof(f))
210 			err = NULL; /* ignore empty files (could be locks) */
211 		else {
212 			if (errno == EISDIR)
213 				err = got_error(GOT_ERR_NOT_REF);
214 			else if (ferror(f))
215 				err = got_ferror(f, GOT_ERR_IO);
216 			else
217 				err = got_error_from_errno2("getline", abspath);
218 		}
219 		if (lock)
220 			got_lockfile_unlock(lf, -1);
221 		goto done;
222 	}
223 	while (linelen > 0 && line[linelen - 1] == '\n') {
224 		line[linelen - 1] = '\0';
225 		linelen--;
226 	}
227 
228 	err = parse_ref_line(ref, absname, line, sb.st_mtime);
229 	if (lock) {
230 		if (err)
231 			got_lockfile_unlock(lf, -1);
232 		else {
233 			if (*ref)
234 				(*ref)->lf = lf;
235 			else
236 				got_lockfile_unlock(lf, -1);
237 		}
238 	}
239 done:
240 	free(line);
241 	if (fclose(f) == EOF && err == NULL) {
242 		err = got_error_from_errno("fclose");
243 		if (*ref) {
244 			if (lock)
245 				got_ref_unlock(*ref);
246 			got_ref_close(*ref);
247 			*ref = NULL;
248 		}
249 	}
250 	return err;
251 }
252 
253 static int
254 is_well_known_ref(const char *refname)
255 {
256 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
257 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
258 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
259 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
260 }
261 
262 static char *
263 get_refs_dir_path(struct got_repository *repo, const char *refname)
264 {
265 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
266 		return strdup(got_repo_get_path_git_dir(repo));
267 
268 	return got_repo_get_path_refs(repo);
269 }
270 
271 int
272 got_ref_name_is_valid(const char *name)
273 {
274 	const char *s, *seg;
275 	const char forbidden[] = { ' ', '~', '^', ':', '?', '*', '[' , '\\' };
276 	const char *forbidden_seq[] = { "//", "..", "@{" };
277 	const char *lfs = GOT_LOCKFILE_SUFFIX;
278 	const size_t lfs_len = sizeof(GOT_LOCKFILE_SUFFIX) - 1;
279 	size_t i;
280 
281 	if (name[0] == '@' && name[1] == '\0')
282 		return 0;
283 
284 	s = name;
285 	seg = s;
286 	if (seg[0] == '\0' || seg[0] == '.' || seg[0] == '/')
287 		return 0;
288 	while (*s) {
289 		for (i = 0; i < nitems(forbidden); i++) {
290 			if (*s == forbidden[i])
291 				return 0;
292 		}
293 		for (i = 0; i < nitems(forbidden_seq); i++) {
294 			if (s[0] == forbidden_seq[i][0] &&
295 			    s[1] == forbidden_seq[i][1])
296 				return 0;
297 		}
298 		if (iscntrl((unsigned char)s[0]))
299 			return 0;
300 		if (s[0] == '.' && s[1] == '\0')
301 			return 0;
302 		if (*s == '/') {
303 			const char *nextseg = s + 1;
304 			if (nextseg[0] == '\0' || nextseg[0] == '.' ||
305 			    nextseg[0] == '/')
306 				return 0;
307 			if (seg <= s - lfs_len &&
308 			    strncmp(s - lfs_len, lfs, lfs_len) == 0)
309 				return 0;
310 			seg = nextseg;
311 		}
312 		s++;
313 	}
314 
315 	if (seg <= s - lfs_len &&
316 	    strncmp(s - lfs_len, lfs, lfs_len) == 0)
317 		return 0;
318 
319 	return 1;
320 }
321 
322 const struct got_error *
323 got_ref_alloc(struct got_reference **ref, const char *name,
324     struct got_object_id *id)
325 {
326 	if (!got_ref_name_is_valid(name))
327 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
328 
329 	return alloc_ref(ref, name, id, 0, 0);
330 }
331 
332 const struct got_error *
333 got_ref_alloc_symref(struct got_reference **ref, const char *name,
334 	struct got_reference *target_ref)
335 {
336 	if (!got_ref_name_is_valid(name))
337 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
338 
339 	return alloc_symref(ref, name, got_ref_get_name(target_ref), 0);
340 }
341 
342 static const struct got_error *
343 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
344     const char *line, time_t mtime)
345 {
346 	struct got_object_id id;
347 	const char *name;
348 
349 	*ref = NULL;
350 
351 	if (line[0] == '#' || line[0] == '^')
352 		return NULL;
353 
354 	if (!got_parse_sha1_digest(id.sha1, line))
355 		return got_error(GOT_ERR_BAD_REF_DATA);
356 
357 	if (abs_refname) {
358 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
359 			return NULL;
360 		name = abs_refname;
361 	} else
362 		name = line + SHA1_DIGEST_STRING_LENGTH;
363 
364 	return alloc_ref(ref, name, &id, GOT_REF_IS_PACKED, mtime);
365 }
366 
367 static const struct got_error *
368 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
369     int nsubdirs, const char *refname, time_t mtime)
370 {
371 	const struct got_error *err = NULL;
372 	char *abs_refname;
373 	char *line = NULL;
374 	size_t linesize = 0;
375 	ssize_t linelen;
376 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
377 
378 	*ref = NULL;
379 
380 	if (ref_is_absolute)
381 		abs_refname = (char *)refname;
382 	do {
383 		linelen = getline(&line, &linesize, f);
384 		if (linelen == -1) {
385 			if (feof(f))
386 				break;
387 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
388 			break;
389 		}
390 		if (linelen > 0 && line[linelen - 1] == '\n')
391 			line[linelen - 1] = '\0';
392 		for (i = 0; i < nsubdirs; i++) {
393 			if (!ref_is_absolute &&
394 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
395 			    refname) == -1)
396 				return got_error_from_errno("asprintf");
397 			err = parse_packed_ref_line(ref, abs_refname, line,
398 			    mtime);
399 			if (!ref_is_absolute)
400 				free(abs_refname);
401 			if (err || *ref != NULL)
402 				break;
403 		}
404 		if (err)
405 			break;
406 	} while (*ref == NULL);
407 	free(line);
408 
409 	return err;
410 }
411 
412 static const struct got_error *
413 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
414     const char *name, int lock)
415 {
416 	const struct got_error *err = NULL;
417 	char *path = NULL;
418 	char *absname = NULL;
419 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
420 	int ref_is_well_known = (subdir[0] == '\0' && is_well_known_ref(name));
421 
422 	*ref = NULL;
423 
424 	if (!got_ref_name_is_valid(name))
425 		return got_error_path(name, GOT_ERR_BAD_REF_NAME);
426 
427 	if (ref_is_absolute || ref_is_well_known) {
428 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
429 			return got_error_from_errno("asprintf");
430 		absname = (char *)name;
431 	} else {
432 		if (asprintf(&path, "%s/%s%s%s", path_refs, subdir,
433 		    subdir[0] ? "/" : "", name) == -1)
434 			return got_error_from_errno("asprintf");
435 
436 		if (asprintf(&absname, "refs/%s%s%s",
437 		    subdir, subdir[0] ? "/" : "", name) == -1) {
438 			err = got_error_from_errno("asprintf");
439 			goto done;
440 		}
441 	}
442 
443 	err = parse_ref_file(ref, name, absname, path, lock);
444 done:
445 	if (!ref_is_absolute && !ref_is_well_known)
446 		free(absname);
447 	free(path);
448 	return err;
449 }
450 
451 const struct got_error *
452 got_ref_open(struct got_reference **ref, struct got_repository *repo,
453     const char *refname, int lock)
454 {
455 	const struct got_error *err = NULL;
456 	char *path_refs = NULL;
457 	const char *subdirs[] = {
458 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
459 	};
460 	size_t i;
461 	int well_known = is_well_known_ref(refname);
462 	struct got_lockfile *lf = NULL;
463 
464 	*ref = NULL;
465 
466 	path_refs = get_refs_dir_path(repo, refname);
467 	if (path_refs == NULL) {
468 		err = got_error_from_errno2("get_refs_dir_path", refname);
469 		goto done;
470 	}
471 
472 	if (well_known) {
473 		err = open_ref(ref, path_refs, "", refname, lock);
474 	} else {
475 		char *packed_refs_path;
476 		FILE *f;
477 
478 		/* Search on-disk refs before packed refs! */
479 		for (i = 0; i < nitems(subdirs); i++) {
480 			err = open_ref(ref, path_refs, subdirs[i], refname,
481 			    lock);
482 			if ((err && err->code != GOT_ERR_NOT_REF) || *ref)
483 				goto done;
484 		}
485 
486 		packed_refs_path = got_repo_get_path_packed_refs(repo);
487 		if (packed_refs_path == NULL) {
488 			err = got_error_from_errno(
489 			    "got_repo_get_path_packed_refs");
490 			goto done;
491 		}
492 
493 		if (lock) {
494 			err = got_lockfile_lock(&lf, packed_refs_path, -1);
495 			if (err)
496 				goto done;
497 		}
498 		f = fopen(packed_refs_path, "rb");
499 		free(packed_refs_path);
500 		if (f != NULL) {
501 			struct stat sb;
502 			if (fstat(fileno(f), &sb) == -1) {
503 				err = got_error_from_errno2("fstat",
504 				    packed_refs_path);
505 				goto done;
506 			}
507 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
508 			    refname, sb.st_mtime);
509 			if (!err) {
510 				if (fclose(f) == EOF) {
511 					err = got_error_from_errno("fclose");
512 					got_ref_close(*ref);
513 					*ref = NULL;
514 				} else if (*ref)
515 					(*ref)->lf = lf;
516 			}
517 		}
518 	}
519 done:
520 	if (!err && *ref == NULL)
521 		err = got_error_not_ref(refname);
522 	if (err && lf)
523 		got_lockfile_unlock(lf, -1);
524 	free(path_refs);
525 	return err;
526 }
527 
528 void
529 got_ref_close(struct got_reference *ref)
530 {
531 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
532 		free(ref->ref.symref.name);
533 		free(ref->ref.symref.ref);
534 	} else
535 		free(ref->ref.ref.name);
536 	free(ref);
537 }
538 
539 struct got_reference *
540 got_ref_dup(struct got_reference *ref)
541 {
542 	struct got_reference *ret;
543 
544 	ret = calloc(1, sizeof(*ret));
545 	if (ret == NULL)
546 		return NULL;
547 
548 	ret->flags = ref->flags;
549 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
550 		ret->ref.symref.name = strdup(ref->ref.symref.name);
551 		if (ret->ref.symref.name == NULL) {
552 			free(ret);
553 			return NULL;
554 		}
555 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
556 		if (ret->ref.symref.ref == NULL) {
557 			free(ret->ref.symref.name);
558 			free(ret);
559 			return NULL;
560 		}
561 	} else {
562 		ret->ref.ref.name = strdup(ref->ref.ref.name);
563 		if (ret->ref.ref.name == NULL) {
564 			free(ret);
565 			return NULL;
566 		}
567 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
568 		    sizeof(ret->ref.ref.sha1));
569 	}
570 
571 	return ret;
572 }
573 
574 const struct got_error *
575 got_reflist_entry_dup(struct got_reflist_entry **newp,
576     struct got_reflist_entry *re)
577 {
578 	const struct got_error *err = NULL;
579 	struct got_reflist_entry *new;
580 
581 	*newp = NULL;
582 
583 	new = malloc(sizeof(*new));
584 	if (new == NULL)
585 		return got_error_from_errno("malloc");
586 
587 	new->ref = got_ref_dup(re->ref);
588 	if (new->ref == NULL) {
589 		err = got_error_from_errno("got_ref_dup");
590 		free(new);
591 		return err;
592 	}
593 
594 	*newp = new;
595 	return NULL;
596 }
597 
598 const struct got_error *
599 got_ref_resolve_symbolic(struct got_reference **resolved,
600     struct got_repository *repo, struct got_reference *ref)
601 {
602 	struct got_reference *nextref;
603 	const struct got_error *err;
604 
605 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref, 0);
606 	if (err)
607 		return err;
608 
609 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
610 		err = got_ref_resolve_symbolic(resolved, repo, nextref);
611 	else
612 		*resolved = got_ref_dup(nextref);
613 
614 	got_ref_close(nextref);
615 	return err;
616 }
617 
618 static const struct got_error *
619 ref_resolve(struct got_object_id **id, struct got_repository *repo,
620     struct got_reference *ref, int recursion)
621 {
622 	const struct got_error *err;
623 
624 	if (recursion <= 0)
625 		return got_error_msg(GOT_ERR_RECURSION,
626 		    "reference recursion limit reached");
627 
628 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
629 		struct got_reference *resolved = NULL;
630 		err = got_ref_resolve_symbolic(&resolved, repo, ref);
631 		if (err == NULL)
632 			err = ref_resolve(id, repo, resolved, --recursion);
633 		if (resolved)
634 			got_ref_close(resolved);
635 		return err;
636 	}
637 
638 	*id = calloc(1, sizeof(**id));
639 	if (*id == NULL)
640 		return got_error_from_errno("calloc");
641 	memcpy((*id)->sha1, ref->ref.ref.sha1, sizeof((*id)->sha1));
642 	return NULL;
643 }
644 
645 const struct got_error *
646 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
647     struct got_reference *ref)
648 {
649 	return ref_resolve(id, repo, ref, GOT_REF_RECURSE_MAX);
650 }
651 
652 char *
653 got_ref_to_str(struct got_reference *ref)
654 {
655 	char *str;
656 
657 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
658 		return strdup(ref->ref.symref.ref);
659 
660 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
661 	if (str == NULL)
662 		return NULL;
663 
664 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
665 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
666 		free(str);
667 		return NULL;
668 	}
669 
670 	return str;
671 }
672 
673 const char *
674 got_ref_get_name(struct got_reference *ref)
675 {
676 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
677 		return ref->ref.symref.name;
678 
679 	return ref->ref.ref.name;
680 }
681 
682 const char *
683 got_ref_get_symref_target(struct got_reference *ref)
684 {
685 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
686 		return ref->ref.symref.ref;
687 
688 	return NULL;
689 }
690 
691 time_t
692 got_ref_get_mtime(struct got_reference *ref)
693 {
694 	return ref->mtime;
695 }
696 
697 const struct got_error *
698 got_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
699     struct got_reference* re2)
700 {
701 	const char *name1 = got_ref_get_name(re1);
702 	const char *name2 = got_ref_get_name(re2);
703 
704 	*cmp = got_path_cmp(name1, name2, strlen(name1), strlen(name2));
705 	return NULL;
706 }
707 
708 const struct got_error *
709 got_ref_cmp_tags(void *arg, int *cmp, struct got_reference *ref1,
710     struct got_reference *ref2)
711 {
712 	const struct got_error *err = NULL;
713 	struct got_repository *repo = arg;
714 	struct got_object_id *id1, *id2 = NULL;
715 	struct got_tag_object *tag1 = NULL, *tag2 = NULL;
716 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
717 	time_t time1, time2;
718 
719 	*cmp = 0;
720 
721 	err = got_ref_resolve(&id1, repo, ref1);
722 	if (err)
723 		return err;
724 	err = got_object_open_as_tag(&tag1, repo, id1);
725 	if (err) {
726 		if (err->code != GOT_ERR_OBJ_TYPE)
727 			goto done;
728 		/* "lightweight" tag */
729 		err = got_object_open_as_commit(&commit1, repo, id1);
730 		if (err)
731 			goto done;
732 		time1 = got_object_commit_get_committer_time(commit1);
733 	} else
734 		time1 = got_object_tag_get_tagger_time(tag1);
735 
736 	err = got_ref_resolve(&id2, repo, ref2);
737 	if (err)
738 		goto done;
739 	err = got_object_open_as_tag(&tag2, repo, id2);
740 	if (err) {
741 		if (err->code != GOT_ERR_OBJ_TYPE)
742 			goto done;
743 		/* "lightweight" tag */
744 		err = got_object_open_as_commit(&commit2, repo, id2);
745 		if (err)
746 			goto done;
747 		time2 = got_object_commit_get_committer_time(commit2);
748 	} else
749 		time2 = got_object_tag_get_tagger_time(tag2);
750 
751 	/* Put latest tags first. */
752 	if (time1 < time2)
753 		*cmp = 1;
754 	else if (time1 > time2)
755 		*cmp = -1;
756 	else
757 		err = got_ref_cmp_by_name(NULL, cmp, ref2, ref1);
758 done:
759 	free(id1);
760 	free(id2);
761 	if (tag1)
762 		got_object_tag_close(tag1);
763 	if (tag2)
764 		got_object_tag_close(tag2);
765 	if (commit1)
766 		got_object_commit_close(commit1);
767 	if (commit2)
768 		got_object_commit_close(commit2);
769 	return err;
770 }
771 
772 const struct got_error *
773 got_ref_cmp_by_commit_timestamp_descending(void *arg, int *cmp,
774     struct got_reference *ref1, struct got_reference *ref2)
775 {
776 	const struct got_error *err;
777 	struct got_repository *repo = arg;
778 	struct got_object_id *id1 = NULL, *id2 = NULL;
779 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
780 
781 	*cmp = 0;
782 
783 	if (ref1->committer_time == 0) {
784 		err = got_ref_resolve(&id1, repo, ref1);
785 		if (err)
786 			return err;
787 		err = got_object_open_as_commit(&commit1, repo, id1);
788 		if (err)
789 			goto done;
790 		ref1->committer_time =
791 		    got_object_commit_get_committer_time(commit1);
792 	}
793 
794 	if (ref2->committer_time == 0) {
795 		err = got_ref_resolve(&id2, repo, ref2);
796 		if (err)
797 			return err;
798 		err = got_object_open_as_commit(&commit2, repo, id2);
799 		if (err)
800 			goto done;
801 		ref2->committer_time =
802 		    got_object_commit_get_committer_time(commit2);
803 	}
804 
805 	if (ref1->committer_time < ref2->committer_time)
806 		*cmp = 1;
807 	else if (ref2->committer_time < ref1->committer_time)
808 		*cmp = -1;
809 done:
810 	free(id1);
811 	free(id2);
812 	if (commit1)
813 		got_object_commit_close(commit1);
814 	if (commit2)
815 		got_object_commit_close(commit2);
816 	return err;
817 }
818 
819 const struct got_error *
820 got_reflist_insert(struct got_reflist_entry **newp, struct got_reflist_head *refs,
821     struct got_reference *ref, got_ref_cmp_cb cmp_cb, void *cmp_arg)
822 {
823 	const struct got_error *err;
824 	struct got_reflist_entry *new, *re;
825 	int cmp;
826 
827 	*newp = NULL;
828 
829 	new = malloc(sizeof(*new));
830 	if (new == NULL)
831 		return got_error_from_errno("malloc");
832 	new->ref = ref;
833 	*newp = new;
834 
835 	/*
836 	 * We must de-duplicate entries on insert because packed-refs may
837 	 * contain redundant entries. On-disk refs take precedence.
838 	 * This code assumes that on-disk revs are read before packed-refs.
839 	 * We're iterating the list anyway, so insert elements sorted by name.
840 	 *
841 	 * Many callers will provide paths in a somewhat sorted order.
842 	 * Iterating backwards from the tail of the list should be more
843 	 * efficient than traversing through the entire list each time
844 	 * an element is inserted.
845 	 */
846 	re = TAILQ_LAST(refs, got_reflist_head);
847 	while (re) {
848 		err = (*cmp_cb)(cmp_arg, &cmp, re->ref, new->ref);
849 		if (err)
850 			return err;
851 		if (cmp == 0) {
852 			/* duplicate */
853 			free(new);
854 			*newp = NULL;
855 			return NULL;
856 		} else if (cmp < 0) {
857 			TAILQ_INSERT_AFTER(refs, re, new, entry);
858 			return NULL;
859 		}
860 		re = TAILQ_PREV(re, got_reflist_head, entry);
861 	}
862 
863 	TAILQ_INSERT_HEAD(refs, new, entry);
864 	return NULL;
865 }
866 
867 static const struct got_error *
868 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
869     const char *subdir, struct got_repository *repo,
870     got_ref_cmp_cb cmp_cb, void *cmp_arg)
871 {
872 	const struct got_error *err = NULL;
873 	DIR *d = NULL;
874 	char *path_subdir;
875 
876 	while (subdir[0] == '/')
877 		subdir++;
878 
879 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
880 		return got_error_from_errno("asprintf");
881 
882 	d = opendir(path_subdir);
883 	if (d == NULL)
884 		goto done;
885 
886 	for (;;) {
887 		struct dirent *dent;
888 		struct got_reference *ref;
889 		char *child;
890 		int type;
891 
892 		dent = readdir(d);
893 		if (dent == NULL)
894 			break;
895 
896 		if (strcmp(dent->d_name, ".") == 0 ||
897 		    strcmp(dent->d_name, "..") == 0)
898 			continue;
899 
900 		err = got_path_dirent_type(&type, path_subdir, dent);
901 		if (err)
902 			break;
903 
904 		switch (type) {
905 		case DT_REG:
906 			err = open_ref(&ref, path_refs, subdir, dent->d_name,
907 			    0);
908 			if (err)
909 				goto done;
910 			if (ref) {
911 				struct got_reflist_entry *new;
912 				err = got_reflist_insert(&new, refs, ref,
913 				    cmp_cb, cmp_arg);
914 				if (err || new == NULL /* duplicate */)
915 					got_ref_close(ref);
916 				if (err)
917 					goto done;
918 			}
919 			break;
920 		case DT_DIR:
921 			if (asprintf(&child, "%s%s%s", subdir,
922 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
923 				err = got_error_from_errno("asprintf");
924 				break;
925 			}
926 			err = gather_on_disk_refs(refs, path_refs, child, repo,
927 			    cmp_cb, cmp_arg);
928 			free(child);
929 			break;
930 		default:
931 			break;
932 		}
933 	}
934 done:
935 	if (d)
936 		closedir(d);
937 	free(path_subdir);
938 	return err;
939 }
940 
941 const struct got_error *
942 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo,
943     const char *ref_namespace, got_ref_cmp_cb cmp_cb, void *cmp_arg)
944 {
945 	const struct got_error *err;
946 	char *packed_refs_path, *path_refs = NULL;
947 	char *abs_namespace = NULL;
948 	char *buf = NULL, *ondisk_ref_namespace = NULL;
949 	char *line = NULL;
950 	FILE *f = NULL;
951 	struct got_reference *ref;
952 	struct got_reflist_entry *new;
953 
954 	if (ref_namespace == NULL || ref_namespace[0] == '\0') {
955 		path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
956 		if (path_refs == NULL) {
957 			err = got_error_from_errno("get_refs_dir_path");
958 			goto done;
959 		}
960 		err = open_ref(&ref, path_refs, "", GOT_REF_HEAD, 0);
961 		if (err)
962 			goto done;
963 		err = got_reflist_insert(&new, refs, ref, cmp_cb, cmp_arg);
964 		if (err || new == NULL /* duplicate */)
965 			got_ref_close(ref);
966 		if (err && err->code != GOT_ERR_NOT_REF)
967 			goto done;
968 	} else {
969 		/* Try listing a single reference. */
970 		const char *refname = ref_namespace;
971 		path_refs = get_refs_dir_path(repo, refname);
972 		if (path_refs == NULL) {
973 			err = got_error_from_errno("get_refs_dir_path");
974 			goto done;
975 		}
976 		err = open_ref(&ref, path_refs, "", refname, 0);
977 		if (err) {
978 			if (err->code != GOT_ERR_NOT_REF)
979 				goto done;
980 			/* Try to look up references in a given namespace. */
981 		} else {
982 			err = got_reflist_insert(&new, refs, ref,
983 			    cmp_cb, cmp_arg);
984 			if (err || new == NULL /* duplicate */)
985 				got_ref_close(ref);
986 			return err;
987 		}
988 	}
989 
990 	if (ref_namespace) {
991 		size_t len;
992 		/* Canonicalize the path to eliminate double-slashes if any. */
993 		if (asprintf(&abs_namespace, "/%s", ref_namespace) == -1) {
994 			err = got_error_from_errno("asprintf");
995 			goto done;
996 		}
997 		len = strlen(abs_namespace) + 1;
998 		buf = malloc(len);
999 		if (buf == NULL) {
1000 			err = got_error_from_errno("malloc");
1001 			goto done;
1002 		}
1003 		err = got_canonpath(abs_namespace, buf, len);
1004 		if (err)
1005 			goto done;
1006 		ondisk_ref_namespace = buf;
1007 		while (ondisk_ref_namespace[0] == '/')
1008 			ondisk_ref_namespace++;
1009 		if (strncmp(ondisk_ref_namespace, "refs/", 5) == 0)
1010 			ondisk_ref_namespace += 5;
1011 		else if (strcmp(ondisk_ref_namespace, "refs") == 0)
1012 			ondisk_ref_namespace = "";
1013 	}
1014 
1015 	/* Gather on-disk refs before parsing packed-refs. */
1016 	free(path_refs);
1017 	path_refs = get_refs_dir_path(repo, "");
1018 	if (path_refs == NULL) {
1019 		err = got_error_from_errno("get_refs_dir_path");
1020 		goto done;
1021 	}
1022 	err = gather_on_disk_refs(refs, path_refs,
1023 	    ondisk_ref_namespace ? ondisk_ref_namespace : "", repo,
1024 	    cmp_cb, cmp_arg);
1025 	if (err)
1026 		goto done;
1027 
1028 	/*
1029 	 * The packed-refs file may contain redundant entries, in which
1030 	 * case on-disk refs take precedence.
1031 	 */
1032 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1033 	if (packed_refs_path == NULL) {
1034 		err = got_error_from_errno("got_repo_get_path_packed_refs");
1035 		goto done;
1036 	}
1037 
1038 	f = fopen(packed_refs_path, "r");
1039 	free(packed_refs_path);
1040 	if (f) {
1041 		size_t linesize = 0;
1042 		ssize_t linelen;
1043 		struct stat sb;
1044 
1045 		if (fstat(fileno(f), &sb) == -1) {
1046 			err = got_error_from_errno2("fstat", packed_refs_path);
1047 			goto done;
1048 		}
1049 		for (;;) {
1050 			linelen = getline(&line, &linesize, f);
1051 			if (linelen == -1) {
1052 				if (feof(f))
1053 					break;
1054 				err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1055 				goto done;
1056 			}
1057 			if (linelen > 0 && line[linelen - 1] == '\n')
1058 				line[linelen - 1] = '\0';
1059 			err = parse_packed_ref_line(&ref, NULL, line,
1060 			    sb.st_mtime);
1061 			if (err)
1062 				goto done;
1063 			if (ref) {
1064 				if (ref_namespace) {
1065 					const char *name;
1066 					name = got_ref_get_name(ref);
1067 					if (!got_path_is_child(name,
1068 					    ref_namespace,
1069 					    strlen(ref_namespace))) {
1070 						got_ref_close(ref);
1071 						continue;
1072 					}
1073 				}
1074 				err = got_reflist_insert(&new, refs, ref,
1075 				    cmp_cb, cmp_arg);
1076 				if (err || new == NULL /* duplicate */)
1077 					got_ref_close(ref);
1078 				if (err)
1079 					goto done;
1080 			}
1081 		}
1082 	}
1083 done:
1084 	free(abs_namespace);
1085 	free(buf);
1086 	free(line);
1087 	free(path_refs);
1088 	if (f && fclose(f) == EOF && err == NULL)
1089 		err = got_error_from_errno("fclose");
1090 	return err;
1091 }
1092 
1093 void
1094 got_ref_list_free(struct got_reflist_head *refs)
1095 {
1096 	struct got_reflist_entry *re;
1097 
1098 	while ((re = TAILQ_FIRST(refs))) {
1099 		TAILQ_REMOVE(refs, re, entry);
1100 		got_ref_close(re->ref);
1101 		free(re);
1102 	}
1103 
1104 }
1105 
1106 int
1107 got_ref_is_symbolic(struct got_reference *ref)
1108 {
1109 	return (ref->flags & GOT_REF_IS_SYMBOLIC);
1110 }
1111 
1112 const struct got_error *
1113 got_ref_change_ref(struct got_reference *ref, struct got_object_id *id)
1114 {
1115 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
1116 		return got_error(GOT_ERR_BAD_REF_TYPE);
1117 
1118 	memcpy(ref->ref.ref.sha1, id->sha1, sizeof(ref->ref.ref.sha1));
1119 	return NULL;
1120 }
1121 
1122 const struct got_error *
1123 got_ref_change_symref(struct got_reference *ref, const char *refname)
1124 {
1125 	char *new_name;
1126 
1127 	if ((ref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1128 		return got_error(GOT_ERR_BAD_REF_TYPE);
1129 
1130 	new_name = strdup(refname);
1131 	if (new_name == NULL)
1132 		return got_error_from_errno("strdup");
1133 
1134 	free(ref->ref.symref.ref);
1135 	ref->ref.symref.ref = new_name;
1136 	return NULL;
1137 }
1138 
1139 const struct got_error *
1140 got_ref_change_symref_to_ref(struct got_reference *symref,
1141     struct got_object_id *id)
1142 {
1143 	if ((symref->flags & GOT_REF_IS_SYMBOLIC) == 0)
1144 		return got_error(GOT_ERR_BAD_REF_TYPE);
1145 
1146 	symref->ref.ref.name = symref->ref.symref.name;
1147 	memcpy(symref->ref.ref.sha1, id->sha1, SHA1_DIGEST_LENGTH);
1148 	symref->flags &= ~GOT_REF_IS_SYMBOLIC;
1149 	return NULL;
1150 }
1151 
1152 const struct got_error *
1153 got_ref_write(struct got_reference *ref, struct got_repository *repo)
1154 {
1155 	const struct got_error *err = NULL, *unlock_err = NULL;
1156 	const char *name = got_ref_get_name(ref);
1157 	char *path_refs = NULL, *path = NULL, *tmppath = NULL;
1158 	struct got_lockfile *lf = NULL;
1159 	FILE *f = NULL;
1160 	size_t n;
1161 	struct stat sb;
1162 
1163 	path_refs = get_refs_dir_path(repo, name);
1164 	if (path_refs == NULL) {
1165 		err = got_error_from_errno2("get_refs_dir_path", name);
1166 		goto done;
1167 	}
1168 
1169 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1170 		err = got_error_from_errno("asprintf");
1171 		goto done;
1172 	}
1173 
1174 	err = got_opentemp_named(&tmppath, &f, path);
1175 	if (err) {
1176 		char *parent;
1177 		if (!(err->code == GOT_ERR_ERRNO && errno == ENOENT))
1178 			goto done;
1179 		err = got_path_dirname(&parent, path);
1180 		if (err)
1181 			goto done;
1182 		err = got_path_mkdir(parent);
1183 		free(parent);
1184 		if (err)
1185 			goto done;
1186 		err = got_opentemp_named(&tmppath, &f, path);
1187 		if (err)
1188 			goto done;
1189 	}
1190 
1191 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
1192 		n = fprintf(f, "ref: %s\n", ref->ref.symref.ref);
1193 		if (n != strlen(ref->ref.symref.ref) + 6) {
1194 			err = got_ferror(f, GOT_ERR_IO);
1195 			goto done;
1196 		}
1197 	} else {
1198 		char hex[SHA1_DIGEST_STRING_LENGTH];
1199 		if (got_sha1_digest_to_str(ref->ref.ref.sha1, hex,
1200 		    sizeof(hex)) == NULL) {
1201 			err = got_error(GOT_ERR_BAD_REF_DATA);
1202 			goto done;
1203 		}
1204 		n = fprintf(f, "%s\n", hex);
1205 		if (n != sizeof(hex)) {
1206 			err = got_ferror(f, GOT_ERR_IO);
1207 			goto done;
1208 		}
1209 	}
1210 
1211 	if (ref->lf == NULL) {
1212 		err = got_lockfile_lock(&lf, path, -1);
1213 		if (err)
1214 			goto done;
1215 	}
1216 
1217 	/* XXX: check if old content matches our expectations? */
1218 
1219 	if (stat(path, &sb) != 0) {
1220 		if (errno != ENOENT) {
1221 			err = got_error_from_errno2("stat", path);
1222 			goto done;
1223 		}
1224 		sb.st_mode = GOT_DEFAULT_FILE_MODE;
1225 	}
1226 
1227 	if (fchmod(fileno(f), sb.st_mode) != 0) {
1228 		err = got_error_from_errno2("fchmod", tmppath);
1229 		goto done;
1230 	}
1231 
1232 	if (rename(tmppath, path) != 0) {
1233 		err = got_error_from_errno3("rename", tmppath, path);
1234 		goto done;
1235 	}
1236 	free(tmppath);
1237 	tmppath = NULL;
1238 
1239 	if (stat(path, &sb) == -1) {
1240 		err = got_error_from_errno2("stat", path);
1241 		goto done;
1242 	}
1243 	ref->mtime = sb.st_mtime;
1244 done:
1245 	if (ref->lf == NULL && lf)
1246 		unlock_err = got_lockfile_unlock(lf, -1);
1247 	if (f) {
1248 		if (fclose(f) == EOF && err == NULL)
1249 			err = got_error_from_errno("fclose");
1250 	}
1251 	free(path_refs);
1252 	free(path);
1253 	if (tmppath) {
1254 		if (unlink(tmppath) != 0 && err == NULL)
1255 			err = got_error_from_errno2("unlink", tmppath);
1256 		free(tmppath);
1257 	}
1258 	return err ? err : unlock_err;
1259 }
1260 
1261 static const struct got_error *
1262 delete_packed_ref(struct got_reference *delref, struct got_repository *repo)
1263 {
1264 	const struct got_error *err = NULL, *unlock_err = NULL;
1265 	struct got_lockfile *lf = NULL;
1266 	FILE *f = NULL, *tmpf = NULL;
1267 	char *line = NULL, *packed_refs_path, *tmppath = NULL;
1268 	size_t linesize = 0;
1269 	struct got_reflist_head refs;
1270 	int found_delref = 0;
1271 
1272 	/* The packed-refs file does not cotain symbolic references. */
1273 	if (delref->flags & GOT_REF_IS_SYMBOLIC)
1274 		return got_error(GOT_ERR_BAD_REF_DATA);
1275 
1276 	TAILQ_INIT(&refs);
1277 
1278 	packed_refs_path = got_repo_get_path_packed_refs(repo);
1279 	if (packed_refs_path == NULL)
1280 		return got_error_from_errno("got_repo_get_path_packed_refs");
1281 
1282 	err = got_opentemp_named(&tmppath, &tmpf, packed_refs_path);
1283 	if (err)
1284 		goto done;
1285 
1286 	if (delref->lf == NULL) {
1287 		err = got_lockfile_lock(&lf, packed_refs_path, -1);
1288 		if (err)
1289 			goto done;
1290 	}
1291 
1292 	f = fopen(packed_refs_path, "r");
1293 	if (f == NULL) {
1294 		err = got_error_from_errno2("fopen", packed_refs_path);
1295 		goto done;
1296 	}
1297 	for (;;) {
1298 		ssize_t linelen;
1299 		struct got_reference *ref;
1300 		struct got_reflist_entry *new;
1301 
1302 		linelen = getline(&line, &linesize, f);
1303 		if (linelen == -1) {
1304 			if (feof(f))
1305 				break;
1306 			err = got_ferror(f, GOT_ERR_BAD_REF_DATA);
1307 			goto done;
1308 		}
1309 		if (linelen > 0 && line[linelen - 1] == '\n')
1310 			line[linelen - 1] = '\0';
1311 		err = parse_packed_ref_line(&ref, NULL, line, 0);
1312 		if (err)
1313 			goto done;
1314 		if (ref == NULL)
1315 			continue;
1316 
1317 		if (strcmp(ref->ref.ref.name, delref->ref.ref.name) == 0 &&
1318 		    memcmp(ref->ref.ref.sha1, delref->ref.ref.sha1,
1319 		    sizeof(delref->ref.ref.sha1)) == 0) {
1320 			found_delref = 1;
1321 			got_ref_close(ref);
1322 			continue;
1323 		}
1324 
1325 		err = got_reflist_insert(&new, &refs, ref,
1326 		    got_ref_cmp_by_name, NULL);
1327 		if (err || new == NULL /* duplicate */)
1328 			got_ref_close(ref);
1329 		if (err)
1330 			goto done;
1331 	}
1332 
1333 	if (found_delref) {
1334 		struct got_reflist_entry *re;
1335 		size_t n;
1336 		struct stat sb;
1337 
1338 		n = fprintf(tmpf, "%s\n", GOT_PACKED_REFS_HEADER);
1339 		if (n != sizeof(GOT_PACKED_REFS_HEADER)) {
1340 			err = got_ferror(f, GOT_ERR_IO);
1341 			goto done;
1342 		}
1343 
1344 		TAILQ_FOREACH(re, &refs, entry) {
1345 			char hex[SHA1_DIGEST_STRING_LENGTH];
1346 
1347 			if (got_sha1_digest_to_str(re->ref->ref.ref.sha1, hex,
1348 			    sizeof(hex)) == NULL) {
1349 				err = got_error(GOT_ERR_BAD_REF_DATA);
1350 				goto done;
1351 			}
1352 			n = fprintf(tmpf, "%s ", hex);
1353 			if (n != sizeof(hex)) {
1354 				err = got_ferror(f, GOT_ERR_IO);
1355 				goto done;
1356 			}
1357 			n = fprintf(tmpf, "%s\n", re->ref->ref.ref.name);
1358 			if (n != strlen(re->ref->ref.ref.name) + 1) {
1359 				err = got_ferror(f, GOT_ERR_IO);
1360 				goto done;
1361 			}
1362 		}
1363 
1364 		if (fflush(tmpf) != 0) {
1365 			err = got_error_from_errno("fflush");
1366 			goto done;
1367 		}
1368 
1369 		if (fstat(fileno(f), &sb) != 0) {
1370 			if (errno != ENOENT) {
1371 				err = got_error_from_errno2("fstat",
1372 				    packed_refs_path);
1373 				goto done;
1374 			}
1375 			sb.st_mode = GOT_DEFAULT_FILE_MODE;
1376 		}
1377 
1378 		if (fchmod(fileno(tmpf), sb.st_mode) != 0) {
1379 			err = got_error_from_errno2("fchmod", tmppath);
1380 			goto done;
1381 		}
1382 
1383 		if (rename(tmppath, packed_refs_path) != 0) {
1384 			err = got_error_from_errno3("rename", tmppath,
1385 			    packed_refs_path);
1386 			goto done;
1387 		}
1388 	}
1389 done:
1390 	if (delref->lf == NULL && lf)
1391 		unlock_err = got_lockfile_unlock(lf, -1);
1392 	if (f) {
1393 		if (fclose(f) == EOF && err == NULL)
1394 			err = got_error_from_errno("fclose");
1395 	}
1396 	if (tmpf) {
1397 		unlink(tmppath);
1398 		if (fclose(tmpf) == EOF && err == NULL)
1399 			err = got_error_from_errno("fclose");
1400 	}
1401 	free(tmppath);
1402 	free(packed_refs_path);
1403 	free(line);
1404 	got_ref_list_free(&refs);
1405 	return err ? err : unlock_err;
1406 }
1407 
1408 static const struct got_error *
1409 delete_loose_ref(struct got_reference *ref, struct got_repository *repo)
1410 {
1411 	const struct got_error *err = NULL, *unlock_err = NULL;
1412 	const char *name = got_ref_get_name(ref);
1413 	char *path_refs = NULL, *path = NULL;
1414 	struct got_lockfile *lf = NULL;
1415 
1416 	path_refs = get_refs_dir_path(repo, name);
1417 	if (path_refs == NULL) {
1418 		err = got_error_from_errno2("get_refs_dir_path", name);
1419 		goto done;
1420 	}
1421 
1422 	if (asprintf(&path, "%s/%s", path_refs, name) == -1) {
1423 		err = got_error_from_errno("asprintf");
1424 		goto done;
1425 	}
1426 
1427 	if (ref->lf == NULL) {
1428 		err = got_lockfile_lock(&lf, path, -1);
1429 		if (err)
1430 			goto done;
1431 	}
1432 
1433 	/* XXX: check if old content matches our expectations? */
1434 
1435 	if (unlink(path) != 0)
1436 		err = got_error_from_errno2("unlink", path);
1437 done:
1438 	if (ref->lf == NULL && lf)
1439 		unlock_err = got_lockfile_unlock(lf, -1);
1440 
1441 	free(path_refs);
1442 	free(path);
1443 	return err ? err : unlock_err;
1444 }
1445 
1446 const struct got_error *
1447 got_ref_delete(struct got_reference *ref, struct got_repository *repo)
1448 {
1449 	const struct got_error *err = NULL;
1450 	struct got_reference *ref2;
1451 
1452 	if (ref->flags & GOT_REF_IS_PACKED) {
1453 		err = delete_packed_ref(ref, repo);
1454 		if (err)
1455 			return err;
1456 
1457 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1458 		if (err) {
1459 			if (err->code == GOT_ERR_NOT_REF)
1460 				return NULL;
1461 			return err;
1462 		}
1463 
1464 		err = delete_loose_ref(ref2, repo);
1465 		got_ref_close(ref2);
1466 		return err;
1467 	} else {
1468 		err = delete_loose_ref(ref, repo);
1469 		if (err)
1470 			return err;
1471 
1472 		err = got_ref_open(&ref2, repo, got_ref_get_name(ref), 0);
1473 		if (err) {
1474 			if (err->code == GOT_ERR_NOT_REF)
1475 				return NULL;
1476 			return err;
1477 		}
1478 
1479 		err = delete_packed_ref(ref2, repo);
1480 		got_ref_close(ref2);
1481 		return err;
1482 	}
1483 }
1484 
1485 const struct got_error *
1486 got_ref_unlock(struct got_reference *ref)
1487 {
1488 	const struct got_error *err;
1489 	err = got_lockfile_unlock(ref->lf, -1);
1490 	ref->lf = NULL;
1491 	return err;
1492 }
1493 
1494 struct got_reflist_object_id_map {
1495 	struct got_object_idset *idset;
1496 };
1497 
1498 struct got_reflist_object_id_map_entry {
1499 	struct got_reflist_head refs;
1500 };
1501 
1502 static const struct got_error *
1503 add_object_id_map_entry(struct got_object_idset *idset,
1504     struct got_object_id *id, struct got_reflist_entry *re)
1505 {
1506 	const struct got_error *err = NULL;
1507 	struct got_reflist_object_id_map_entry *ent;
1508 	struct got_reflist_entry *new;
1509 
1510 	ent = got_object_idset_get(idset, id);
1511 	if (ent == NULL) {
1512 		ent = malloc(sizeof(*ent));
1513 		if (ent == NULL)
1514 			return got_error_from_errno("malloc");
1515 
1516 		TAILQ_INIT(&ent->refs);
1517 		err = got_object_idset_add(idset, id, ent);
1518 		if (err)
1519 			return err;
1520 	}
1521 
1522 	err = got_reflist_entry_dup(&new, re);
1523 	if (err)
1524 		return err;
1525 
1526 	TAILQ_INSERT_TAIL(&ent->refs, new, entry);
1527 	return NULL;
1528 }
1529 
1530 const struct got_error *
1531 got_reflist_object_id_map_create(struct got_reflist_object_id_map **map,
1532     struct got_reflist_head *refs, struct got_repository *repo)
1533 {
1534 	const struct got_error *err = NULL;
1535 	struct got_object_idset *idset;
1536 	struct got_object_id *id = NULL;
1537 	struct got_reflist_entry *re;
1538 
1539 	idset = got_object_idset_alloc();
1540 	if (idset == NULL)
1541 		return got_error_from_errno("got_object_idset_alloc");
1542 
1543 	*map = malloc(sizeof(**map));
1544 	if (*map == NULL) {
1545 		got_object_idset_free(idset);
1546 		return got_error_from_errno("malloc");
1547 	}
1548 	(*map)->idset = idset;
1549 
1550 	TAILQ_FOREACH(re, refs, entry) {
1551 		struct got_tag_object *tag = NULL;
1552 
1553 		err = got_ref_resolve(&id, repo, re->ref);
1554 		if (err)
1555 			goto done;
1556 
1557 		err = add_object_id_map_entry(idset, id, re);
1558 		if (err)
1559 			goto done;
1560 
1561 		if (strstr(got_ref_get_name(re->ref), "/tags/") == NULL) {
1562 			free(id);
1563 			id = NULL;
1564 			continue;
1565 		}
1566 
1567 		err = got_object_open_as_tag(&tag, repo, id);
1568 		if (err) {
1569 			if (err->code != GOT_ERR_OBJ_TYPE)
1570 				goto done;
1571 			/* Ref points at something other than a tag. */
1572 			err = NULL;
1573 			tag = NULL;
1574 			free(id);
1575 			id = NULL;
1576 			continue;
1577 		}
1578 
1579 		err = add_object_id_map_entry(idset,
1580 		    got_object_tag_get_object_id(tag), re);
1581 		got_object_tag_close(tag);
1582 		if (err)
1583 			goto done;
1584 
1585 		free(id);
1586 		id = NULL;
1587 	}
1588 done:
1589 	free(id);
1590 	if (err) {
1591 		got_reflist_object_id_map_free(*map);
1592 		*map = NULL;
1593 	}
1594 	return err;
1595 }
1596 
1597 struct got_reflist_head *
1598 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *map,
1599     struct got_object_id *id)
1600 {
1601 	struct got_reflist_object_id_map_entry *ent;
1602 	ent = got_object_idset_get(map->idset, id);
1603 	if (ent)
1604 		return &ent->refs;
1605 	return NULL;
1606 }
1607 
1608 static const struct got_error *
1609 free_id_map_entry(struct got_object_id *id, void *data, void *arg)
1610 {
1611 	struct got_reflist_object_id_map_entry *ent = data;
1612 
1613 	got_ref_list_free(&ent->refs);
1614 	free(ent);
1615 	return NULL;
1616 }
1617 
1618 void
1619 got_reflist_object_id_map_free(struct got_reflist_object_id_map *map)
1620 {
1621 	got_object_idset_for_each(map->idset, free_id_map_entry, NULL);
1622 	got_object_idset_free(map->idset);
1623 	free(map);
1624 }