refs/files-backend: handle packed transaction prepare failure
[git/git.git] / refs / files-backend.c
CommitLineData
7bd9bcf3 1#include "../cache.h"
b2141fc1 2#include "../config.h"
7bd9bcf3
MH
3#include "../refs.h"
4#include "refs-internal.h"
958f9646 5#include "ref-cache.h"
67be7c5a 6#include "packed-backend.h"
3bc581b9 7#include "../iterator.h"
2880d16f 8#include "../dir-iterator.h"
7bd9bcf3
MH
9#include "../lockfile.h"
10#include "../object.h"
11#include "../dir.h"
fb9c2d27 12#include "../chdir-notify.h"
3a3b9d8c 13#include "worktree.h"
7bd9bcf3 14
5ac95fee
MH
15/*
16 * This backend uses the following flags in `ref_update::flags` for
17 * internal bookkeeping purposes. Their numerical values must not
91774afc 18 * conflict with REF_NO_DEREF, REF_FORCE_CREATE_REFLOG, REF_HAVE_NEW,
acedcde7 19 * REF_HAVE_OLD, or REF_IS_PRUNING, which are also stored in
5ac95fee
MH
20 * `ref_update::flags`.
21 */
22
23/*
24 * Used as a flag in ref_update::flags when a loose ref is being
91774afc 25 * pruned. This flag must only be used when REF_NO_DEREF is set.
5ac95fee 26 */
acedcde7 27#define REF_IS_PRUNING (1 << 4)
5ac95fee
MH
28
29/*
30 * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
31 * refs (i.e., because the reference is about to be deleted anyway).
32 */
33#define REF_DELETING (1 << 5)
34
35/*
36 * Used as a flag in ref_update::flags when the lockfile needs to be
37 * committed.
38 */
39#define REF_NEEDS_COMMIT (1 << 6)
40
41/*
42 * Used as a flag in ref_update::flags when we want to log a ref
43 * update but not actually perform it. This is used when a symbolic
44 * ref update is split up.
45 */
46#define REF_LOG_ONLY (1 << 7)
47
48/*
49 * Used as a flag in ref_update::flags when the ref_update was via an
50 * update to HEAD.
51 */
52#define REF_UPDATE_VIA_HEAD (1 << 8)
53
54/*
55 * Used as a flag in ref_update::flags when the loose reference has
56 * been deleted.
57 */
58#define REF_DELETED_LOOSE (1 << 9)
59
7bd9bcf3
MH
60struct ref_lock {
61 char *ref_name;
ee4d8e45 62 struct lock_file lk;
7bd9bcf3
MH
63 struct object_id old_oid;
64};
65
00eebe35
MH
66struct files_ref_store {
67 struct ref_store base;
9e7ec634 68 unsigned int store_flags;
32c597e7 69
f57f37e2
NTND
70 char *gitdir;
71 char *gitcommondir;
33dfb9f3 72
7c22bc8a 73 struct ref_cache *loose;
55c6bc37 74
e0cc8ac8 75 struct ref_store *packed_ref_store;
00eebe35 76};
7bd9bcf3 77
65a0a8e5 78static void clear_loose_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
79{
80 if (refs->loose) {
7c22bc8a 81 free_ref_cache(refs->loose);
7bd9bcf3
MH
82 refs->loose = NULL;
83 }
84}
85
a2d5156c
JK
86/*
87 * Create a new submodule ref cache and add it to the internal
88 * set of caches.
89 */
9e7ec634
NTND
90static struct ref_store *files_ref_store_create(const char *gitdir,
91 unsigned int flags)
7bd9bcf3 92{
00eebe35
MH
93 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
94 struct ref_store *ref_store = (struct ref_store *)refs;
f57f37e2 95 struct strbuf sb = STRBUF_INIT;
7bd9bcf3 96
fbfd0a29 97 base_ref_store_init(ref_store, &refs_be_files);
9e7ec634 98 refs->store_flags = flags;
7bd9bcf3 99
f57f37e2
NTND
100 refs->gitdir = xstrdup(gitdir);
101 get_common_dir_noenv(&sb, gitdir);
102 refs->gitcommondir = strbuf_detach(&sb, NULL);
103 strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
e0d48397
MH
104 refs->packed_ref_store = packed_ref_store_create(sb.buf, flags);
105 strbuf_release(&sb);
7bd9bcf3 106
fb9c2d27
JK
107 chdir_notify_reparent("files-backend $GIT_DIR",
108 &refs->gitdir);
109 chdir_notify_reparent("files-backend $GIT_COMMONDIR",
110 &refs->gitcommondir);
111
00eebe35 112 return ref_store;
a2d5156c 113}
7bd9bcf3 114
32c597e7 115/*
9e7ec634
NTND
116 * Die if refs is not the main ref store. caller is used in any
117 * necessary error messages.
32c597e7
MH
118 */
119static void files_assert_main_repository(struct files_ref_store *refs,
120 const char *caller)
121{
9e7ec634
NTND
122 if (refs->store_flags & REF_STORE_MAIN)
123 return;
124
033abf97 125 BUG("operation %s only allowed for main ref store", caller);
32c597e7
MH
126}
127
a2d5156c 128/*
00eebe35 129 * Downcast ref_store to files_ref_store. Die if ref_store is not a
9e7ec634
NTND
130 * files_ref_store. required_flags is compared with ref_store's
131 * store_flags to ensure the ref_store has all required capabilities.
132 * "caller" is used in any necessary error messages.
a2d5156c 133 */
9e7ec634
NTND
134static struct files_ref_store *files_downcast(struct ref_store *ref_store,
135 unsigned int required_flags,
136 const char *caller)
a2d5156c 137{
32c597e7
MH
138 struct files_ref_store *refs;
139
00eebe35 140 if (ref_store->be != &refs_be_files)
033abf97 141 BUG("ref_store is type \"%s\" not \"files\" in %s",
00eebe35 142 ref_store->be->name, caller);
2eed2780 143
32c597e7
MH
144 refs = (struct files_ref_store *)ref_store;
145
9e7ec634 146 if ((refs->store_flags & required_flags) != required_flags)
033abf97 147 BUG("operation %s requires abilities 0x%x, but only have 0x%x",
9e7ec634 148 caller, required_flags, refs->store_flags);
2eed2780 149
32c597e7 150 return refs;
7bd9bcf3
MH
151}
152
3a3b9d8c
NTND
153static void files_reflog_path_other_worktrees(struct files_ref_store *refs,
154 struct strbuf *sb,
155 const char *refname)
156{
157 const char *real_ref;
158 const char *worktree_name;
159 int length;
160
161 if (parse_worktree_ref(refname, &worktree_name, &length, &real_ref))
162 BUG("refname %s is not a other-worktree ref", refname);
163
164 if (worktree_name)
165 strbuf_addf(sb, "%s/worktrees/%.*s/logs/%s", refs->gitcommondir,
166 length, worktree_name, real_ref);
167 else
168 strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir,
169 real_ref);
170}
171
802de3da
NTND
172static void files_reflog_path(struct files_ref_store *refs,
173 struct strbuf *sb,
174 const char *refname)
175{
f57f37e2
NTND
176 switch (ref_type(refname)) {
177 case REF_TYPE_PER_WORKTREE:
178 case REF_TYPE_PSEUDOREF:
179 strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
180 break;
3a3b9d8c
NTND
181 case REF_TYPE_OTHER_PSEUDOREF:
182 case REF_TYPE_MAIN_PSEUDOREF:
46c0eb58
NTND
183 files_reflog_path_other_worktrees(refs, sb, refname);
184 break;
f57f37e2
NTND
185 case REF_TYPE_NORMAL:
186 strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
187 break;
188 default:
033abf97 189 BUG("unknown ref type %d of ref %s",
f57f37e2
NTND
190 ref_type(refname), refname);
191 }
802de3da
NTND
192}
193
19e02f4f
NTND
194static void files_ref_path(struct files_ref_store *refs,
195 struct strbuf *sb,
196 const char *refname)
197{
f57f37e2
NTND
198 switch (ref_type(refname)) {
199 case REF_TYPE_PER_WORKTREE:
200 case REF_TYPE_PSEUDOREF:
201 strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
202 break;
3a3b9d8c
NTND
203 case REF_TYPE_MAIN_PSEUDOREF:
204 if (!skip_prefix(refname, "main-worktree/", &refname))
205 BUG("ref %s is not a main pseudoref", refname);
206 /* fallthrough */
207 case REF_TYPE_OTHER_PSEUDOREF:
f57f37e2
NTND
208 case REF_TYPE_NORMAL:
209 strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
210 break;
211 default:
033abf97 212 BUG("unknown ref type %d of ref %s",
f57f37e2
NTND
213 ref_type(refname), refname);
214 }
19e02f4f
NTND
215}
216
7bd9bcf3
MH
217/*
218 * Read the loose references from the namespace dirname into dir
219 * (without recursing). dirname must end with '/'. dir must be the
220 * directory entry corresponding to dirname.
221 */
df308759
MH
222static void loose_fill_ref_dir(struct ref_store *ref_store,
223 struct ref_dir *dir, const char *dirname)
7bd9bcf3 224{
df308759
MH
225 struct files_ref_store *refs =
226 files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
7bd9bcf3
MH
227 DIR *d;
228 struct dirent *de;
229 int dirnamelen = strlen(dirname);
230 struct strbuf refname;
231 struct strbuf path = STRBUF_INIT;
232 size_t path_baselen;
233
19e02f4f 234 files_ref_path(refs, &path, dirname);
7bd9bcf3
MH
235 path_baselen = path.len;
236
237 d = opendir(path.buf);
238 if (!d) {
239 strbuf_release(&path);
240 return;
241 }
242
243 strbuf_init(&refname, dirnamelen + 257);
244 strbuf_add(&refname, dirname, dirnamelen);
245
246 while ((de = readdir(d)) != NULL) {
4417df8c 247 struct object_id oid;
7bd9bcf3
MH
248 struct stat st;
249 int flag;
250
251 if (de->d_name[0] == '.')
252 continue;
253 if (ends_with(de->d_name, ".lock"))
254 continue;
255 strbuf_addstr(&refname, de->d_name);
256 strbuf_addstr(&path, de->d_name);
257 if (stat(path.buf, &st) < 0) {
258 ; /* silently ignore */
259 } else if (S_ISDIR(st.st_mode)) {
260 strbuf_addch(&refname, '/');
261 add_entry_to_dir(dir,
e00d1a4f 262 create_dir_entry(dir->cache, refname.buf,
7bd9bcf3
MH
263 refname.len, 1));
264 } else {
7d2df051 265 if (!refs_resolve_ref_unsafe(&refs->base,
3c0cb0cb
MH
266 refname.buf,
267 RESOLVE_REF_READING,
49e61479 268 &oid, &flag)) {
4417df8c 269 oidclr(&oid);
7bd9bcf3 270 flag |= REF_ISBROKEN;
4417df8c 271 } else if (is_null_oid(&oid)) {
7bd9bcf3
MH
272 /*
273 * It is so astronomically unlikely
78fb4579 274 * that null_oid is the OID of an
7bd9bcf3
MH
275 * actual object that we consider its
276 * appearance in a loose reference
277 * file to be repo corruption
278 * (probably due to a software bug).
279 */
280 flag |= REF_ISBROKEN;
281 }
282
283 if (check_refname_format(refname.buf,
284 REFNAME_ALLOW_ONELEVEL)) {
285 if (!refname_is_safe(refname.buf))
286 die("loose refname is dangerous: %s", refname.buf);
4417df8c 287 oidclr(&oid);
7bd9bcf3
MH
288 flag |= REF_BAD_NAME | REF_ISBROKEN;
289 }
290 add_entry_to_dir(dir,
c1da06c6 291 create_ref_entry(refname.buf, &oid, flag));
7bd9bcf3
MH
292 }
293 strbuf_setlen(&refname, dirnamelen);
294 strbuf_setlen(&path, path_baselen);
295 }
296 strbuf_release(&refname);
297 strbuf_release(&path);
298 closedir(d);
e3bf2989
MH
299
300 /*
8aff1a9c
NTND
301 * Manually add refs/bisect and refs/worktree, which, being
302 * per-worktree, might not appear in the directory listing for
303 * refs/ in the main repo.
e3bf2989
MH
304 */
305 if (!strcmp(dirname, "refs/")) {
306 int pos = search_ref_dir(dir, "refs/bisect/", 12);
307
308 if (pos < 0) {
309 struct ref_entry *child_entry = create_dir_entry(
310 dir->cache, "refs/bisect/", 12, 1);
311 add_entry_to_dir(dir, child_entry);
312 }
8aff1a9c
NTND
313
314 pos = search_ref_dir(dir, "refs/worktree/", 11);
315
316 if (pos < 0) {
317 struct ref_entry *child_entry = create_dir_entry(
318 dir->cache, "refs/worktree/", 11, 1);
319 add_entry_to_dir(dir, child_entry);
320 }
e3bf2989 321 }
7bd9bcf3
MH
322}
323
a714b19c 324static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
325{
326 if (!refs->loose) {
327 /*
328 * Mark the top-level directory complete because we
329 * are about to read the only subdirectory that can
330 * hold references:
331 */
df308759 332 refs->loose = create_ref_cache(&refs->base, loose_fill_ref_dir);
7c22bc8a
MH
333
334 /* We're going to fill the top level ourselves: */
335 refs->loose->root->flag &= ~REF_INCOMPLETE;
336
7bd9bcf3 337 /*
7c22bc8a
MH
338 * Add an incomplete entry for "refs/" (to be filled
339 * lazily):
7bd9bcf3 340 */
7c22bc8a 341 add_entry_to_dir(get_ref_dir(refs->loose->root),
e00d1a4f 342 create_dir_entry(refs->loose, "refs/", 5, 1));
7bd9bcf3 343 }
a714b19c 344 return refs->loose;
7bd9bcf3
MH
345}
346
e1e33b72 347static int files_read_raw_ref(struct ref_store *ref_store,
99afe91a 348 const char *refname, struct object_id *oid,
e1e33b72 349 struct strbuf *referent, unsigned int *type)
7bd9bcf3 350{
4308651c 351 struct files_ref_store *refs =
9e7ec634 352 files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
42a38cf7
MH
353 struct strbuf sb_contents = STRBUF_INIT;
354 struct strbuf sb_path = STRBUF_INIT;
7048653a
DT
355 const char *path;
356 const char *buf;
99afe91a 357 const char *p;
7048653a
DT
358 struct stat st;
359 int fd;
42a38cf7
MH
360 int ret = -1;
361 int save_errno;
e8c42cb9 362 int remaining_retries = 3;
7bd9bcf3 363
fa96ea1b 364 *type = 0;
42a38cf7 365 strbuf_reset(&sb_path);
34c7ad8f 366
19e02f4f 367 files_ref_path(refs, &sb_path, refname);
34c7ad8f 368
42a38cf7 369 path = sb_path.buf;
7bd9bcf3 370
7048653a
DT
371stat_ref:
372 /*
373 * We might have to loop back here to avoid a race
374 * condition: first we lstat() the file, then we try
375 * to read it as a link or as a file. But if somebody
376 * changes the type of the file (file <-> directory
377 * <-> symlink) between the lstat() and reading, then
378 * we don't want to report that as an error but rather
379 * try again starting with the lstat().
e8c42cb9
JK
380 *
381 * We'll keep a count of the retries, though, just to avoid
382 * any confusing situation sending us into an infinite loop.
7048653a 383 */
7bd9bcf3 384
e8c42cb9
JK
385 if (remaining_retries-- <= 0)
386 goto out;
387
7048653a
DT
388 if (lstat(path, &st) < 0) {
389 if (errno != ENOENT)
42a38cf7 390 goto out;
e0cc8ac8 391 if (refs_read_raw_ref(refs->packed_ref_store, refname,
99afe91a 392 oid, referent, type)) {
7048653a 393 errno = ENOENT;
42a38cf7 394 goto out;
7bd9bcf3 395 }
42a38cf7
MH
396 ret = 0;
397 goto out;
7bd9bcf3 398 }
7bd9bcf3 399
7048653a
DT
400 /* Follow "normalized" - ie "refs/.." symlinks by hand */
401 if (S_ISLNK(st.st_mode)) {
42a38cf7 402 strbuf_reset(&sb_contents);
765b496d 403 if (strbuf_readlink(&sb_contents, path, st.st_size) < 0) {
7048653a 404 if (errno == ENOENT || errno == EINVAL)
7bd9bcf3
MH
405 /* inconsistent with lstat; retry */
406 goto stat_ref;
407 else
42a38cf7 408 goto out;
7bd9bcf3 409 }
42a38cf7
MH
410 if (starts_with(sb_contents.buf, "refs/") &&
411 !check_refname_format(sb_contents.buf, 0)) {
92b38093 412 strbuf_swap(&sb_contents, referent);
3a0b6b9a 413 *type |= REF_ISSYMREF;
42a38cf7
MH
414 ret = 0;
415 goto out;
7bd9bcf3 416 }
3f7bd767
JK
417 /*
418 * It doesn't look like a refname; fall through to just
419 * treating it like a non-symlink, and reading whatever it
420 * points to.
421 */
7048653a 422 }
7bd9bcf3 423
7048653a
DT
424 /* Is it a directory? */
425 if (S_ISDIR(st.st_mode)) {
e167a567
MH
426 /*
427 * Even though there is a directory where the loose
428 * ref is supposed to be, there could still be a
429 * packed ref:
430 */
e0cc8ac8 431 if (refs_read_raw_ref(refs->packed_ref_store, refname,
99afe91a 432 oid, referent, type)) {
e167a567
MH
433 errno = EISDIR;
434 goto out;
435 }
436 ret = 0;
42a38cf7 437 goto out;
7048653a
DT
438 }
439
440 /*
441 * Anything else, just open it and try to use it as
442 * a ref
443 */
444 fd = open(path, O_RDONLY);
445 if (fd < 0) {
3f7bd767 446 if (errno == ENOENT && !S_ISLNK(st.st_mode))
7048653a
DT
447 /* inconsistent with lstat; retry */
448 goto stat_ref;
449 else
42a38cf7 450 goto out;
7048653a 451 }
42a38cf7
MH
452 strbuf_reset(&sb_contents);
453 if (strbuf_read(&sb_contents, fd, 256) < 0) {
7048653a
DT
454 int save_errno = errno;
455 close(fd);
456 errno = save_errno;
42a38cf7 457 goto out;
7048653a
DT
458 }
459 close(fd);
42a38cf7
MH
460 strbuf_rtrim(&sb_contents);
461 buf = sb_contents.buf;
7048653a
DT
462 if (starts_with(buf, "ref:")) {
463 buf += 4;
7bd9bcf3
MH
464 while (isspace(*buf))
465 buf++;
7048653a 466
92b38093
MH
467 strbuf_reset(referent);
468 strbuf_addstr(referent, buf);
3a0b6b9a 469 *type |= REF_ISSYMREF;
42a38cf7
MH
470 ret = 0;
471 goto out;
7bd9bcf3 472 }
7bd9bcf3 473
7048653a
DT
474 /*
475 * Please note that FETCH_HEAD has additional
476 * data after the sha.
477 */
99afe91a 478 if (parse_oid_hex(buf, oid, &p) ||
479 (*p != '\0' && !isspace(*p))) {
3a0b6b9a 480 *type |= REF_ISBROKEN;
7048653a 481 errno = EINVAL;
42a38cf7 482 goto out;
7048653a
DT
483 }
484
42a38cf7 485 ret = 0;
7bd9bcf3 486
42a38cf7
MH
487out:
488 save_errno = errno;
7bd9bcf3
MH
489 strbuf_release(&sb_path);
490 strbuf_release(&sb_contents);
42a38cf7 491 errno = save_errno;
7bd9bcf3
MH
492 return ret;
493}
494
8415d247
MH
495static void unlock_ref(struct ref_lock *lock)
496{
ee4d8e45 497 rollback_lock_file(&lock->lk);
8415d247 498 free(lock->ref_name);
8415d247
MH
499 free(lock);
500}
501
92b1551b
MH
502/*
503 * Lock refname, without following symrefs, and set *lock_p to point
504 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
505 * and type similarly to read_raw_ref().
506 *
507 * The caller must verify that refname is a "safe" reference name (in
508 * the sense of refname_is_safe()) before calling this function.
509 *
510 * If the reference doesn't already exist, verify that refname doesn't
511 * have a D/F conflict with any existing references. extras and skip
524a9fdb 512 * are passed to refs_verify_refname_available() for this check.
92b1551b
MH
513 *
514 * If mustexist is not set and the reference is not found or is
78fb4579 515 * broken, lock the reference anyway but clear old_oid.
92b1551b
MH
516 *
517 * Return 0 on success. On failure, write an error message to err and
518 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
519 *
520 * Implementation note: This function is basically
521 *
522 * lock reference
523 * read_raw_ref()
524 *
525 * but it includes a lot more code to
526 * - Deal with possible races with other processes
524a9fdb 527 * - Avoid calling refs_verify_refname_available() when it can be
92b1551b
MH
528 * avoided, namely if we were successfully able to read the ref
529 * - Generate informative error messages in the case of failure
530 */
f7b0a987
MH
531static int lock_raw_ref(struct files_ref_store *refs,
532 const char *refname, int mustexist,
92b1551b
MH
533 const struct string_list *extras,
534 const struct string_list *skip,
535 struct ref_lock **lock_p,
536 struct strbuf *referent,
537 unsigned int *type,
538 struct strbuf *err)
539{
540 struct ref_lock *lock;
541 struct strbuf ref_file = STRBUF_INIT;
542 int attempts_remaining = 3;
543 int ret = TRANSACTION_GENERIC_ERROR;
544
545 assert(err);
32c597e7 546 files_assert_main_repository(refs, "lock_raw_ref");
f7b0a987 547
92b1551b
MH
548 *type = 0;
549
550 /* First lock the file so it can't change out from under us. */
551
552 *lock_p = lock = xcalloc(1, sizeof(*lock));
553
554 lock->ref_name = xstrdup(refname);
19e02f4f 555 files_ref_path(refs, &ref_file, refname);
92b1551b
MH
556
557retry:
558 switch (safe_create_leading_directories(ref_file.buf)) {
559 case SCLD_OK:
560 break; /* success */
561 case SCLD_EXISTS:
562 /*
563 * Suppose refname is "refs/foo/bar". We just failed
564 * to create the containing directory, "refs/foo",
565 * because there was a non-directory in the way. This
566 * indicates a D/F conflict, probably because of
567 * another reference such as "refs/foo". There is no
568 * reason to expect this error to be transitory.
569 */
7d2df051
NTND
570 if (refs_verify_refname_available(&refs->base, refname,
571 extras, skip, err)) {
92b1551b
MH
572 if (mustexist) {
573 /*
574 * To the user the relevant error is
575 * that the "mustexist" reference is
576 * missing:
577 */
578 strbuf_reset(err);
579 strbuf_addf(err, "unable to resolve reference '%s'",
580 refname);
581 } else {
582 /*
583 * The error message set by
524a9fdb
MH
584 * refs_verify_refname_available() is
585 * OK.
92b1551b
MH
586 */
587 ret = TRANSACTION_NAME_CONFLICT;
588 }
589 } else {
590 /*
591 * The file that is in the way isn't a loose
592 * reference. Report it as a low-level
593 * failure.
594 */
595 strbuf_addf(err, "unable to create lock file %s.lock; "
596 "non-directory in the way",
597 ref_file.buf);
598 }
599 goto error_return;
600 case SCLD_VANISHED:
601 /* Maybe another process was tidying up. Try again. */
602 if (--attempts_remaining > 0)
603 goto retry;
604 /* fall through */
605 default:
606 strbuf_addf(err, "unable to create directory for %s",
607 ref_file.buf);
608 goto error_return;
609 }
610
4ff0f01c 611 if (hold_lock_file_for_update_timeout(
ee4d8e45 612 &lock->lk, ref_file.buf, LOCK_NO_DEREF,
4ff0f01c 613 get_files_ref_lock_timeout_ms()) < 0) {
92b1551b
MH
614 if (errno == ENOENT && --attempts_remaining > 0) {
615 /*
616 * Maybe somebody just deleted one of the
617 * directories leading to ref_file. Try
618 * again:
619 */
620 goto retry;
621 } else {
622 unable_to_lock_message(ref_file.buf, errno, err);
623 goto error_return;
624 }
625 }
626
627 /*
628 * Now we hold the lock and can read the reference without
629 * fear that its value will change.
630 */
631
f7b0a987 632 if (files_read_raw_ref(&refs->base, refname,
99afe91a 633 &lock->old_oid, referent, type)) {
92b1551b
MH
634 if (errno == ENOENT) {
635 if (mustexist) {
636 /* Garden variety missing reference. */
637 strbuf_addf(err, "unable to resolve reference '%s'",
638 refname);
639 goto error_return;
640 } else {
641 /*
642 * Reference is missing, but that's OK. We
643 * know that there is not a conflict with
644 * another loose reference because
645 * (supposing that we are trying to lock
646 * reference "refs/foo/bar"):
647 *
648 * - We were successfully able to create
649 * the lockfile refs/foo/bar.lock, so we
650 * know there cannot be a loose reference
651 * named "refs/foo".
652 *
653 * - We got ENOENT and not EISDIR, so we
654 * know that there cannot be a loose
655 * reference named "refs/foo/bar/baz".
656 */
657 }
658 } else if (errno == EISDIR) {
659 /*
660 * There is a directory in the way. It might have
661 * contained references that have been deleted. If
662 * we don't require that the reference already
663 * exists, try to remove the directory so that it
664 * doesn't cause trouble when we want to rename the
665 * lockfile into place later.
666 */
667 if (mustexist) {
668 /* Garden variety missing reference. */
669 strbuf_addf(err, "unable to resolve reference '%s'",
670 refname);
671 goto error_return;
672 } else if (remove_dir_recursively(&ref_file,
673 REMOVE_DIR_EMPTY_ONLY)) {
b05855b5
MH
674 if (refs_verify_refname_available(
675 &refs->base, refname,
676 extras, skip, err)) {
92b1551b
MH
677 /*
678 * The error message set by
679 * verify_refname_available() is OK.
680 */
681 ret = TRANSACTION_NAME_CONFLICT;
682 goto error_return;
683 } else {
684 /*
685 * We can't delete the directory,
686 * but we also don't know of any
687 * references that it should
688 * contain.
689 */
690 strbuf_addf(err, "there is a non-empty directory '%s' "
691 "blocking reference '%s'",
692 ref_file.buf, refname);
693 goto error_return;
694 }
695 }
696 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
697 strbuf_addf(err, "unable to resolve reference '%s': "
698 "reference broken", refname);
699 goto error_return;
700 } else {
701 strbuf_addf(err, "unable to resolve reference '%s': %s",
702 refname, strerror(errno));
703 goto error_return;
704 }
705
706 /*
707 * If the ref did not exist and we are creating it,
8ec617c8
MH
708 * make sure there is no existing packed ref that
709 * conflicts with refname:
92b1551b 710 */
524a9fdb 711 if (refs_verify_refname_available(
8ec617c8 712 refs->packed_ref_store, refname,
524a9fdb 713 extras, skip, err))
92b1551b 714 goto error_return;
92b1551b
MH
715 }
716
717 ret = 0;
718 goto out;
719
720error_return:
721 unlock_ref(lock);
722 *lock_p = NULL;
723
724out:
725 strbuf_release(&ref_file);
726 return ret;
727}
728
3bc581b9
MH
729struct files_ref_iterator {
730 struct ref_iterator base;
731
3bc581b9
MH
732 struct ref_iterator *iter0;
733 unsigned int flags;
734};
7bd9bcf3 735
3bc581b9
MH
736static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
737{
738 struct files_ref_iterator *iter =
739 (struct files_ref_iterator *)ref_iterator;
740 int ok;
7bd9bcf3 741
3bc581b9 742 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
0c09ec07
DT
743 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
744 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
745 continue;
746
3bc581b9
MH
747 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
748 !ref_resolves_to_object(iter->iter0->refname,
749 iter->iter0->oid,
750 iter->iter0->flags))
751 continue;
752
753 iter->base.refname = iter->iter0->refname;
754 iter->base.oid = iter->iter0->oid;
755 iter->base.flags = iter->iter0->flags;
756 return ITER_OK;
7bd9bcf3
MH
757 }
758
3bc581b9
MH
759 iter->iter0 = NULL;
760 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
761 ok = ITER_ERROR;
762
763 return ok;
7bd9bcf3
MH
764}
765
3bc581b9
MH
766static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
767 struct object_id *peeled)
7bd9bcf3 768{
3bc581b9
MH
769 struct files_ref_iterator *iter =
770 (struct files_ref_iterator *)ref_iterator;
93770590 771
3bc581b9
MH
772 return ref_iterator_peel(iter->iter0, peeled);
773}
774
775static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
776{
777 struct files_ref_iterator *iter =
778 (struct files_ref_iterator *)ref_iterator;
779 int ok = ITER_DONE;
780
781 if (iter->iter0)
782 ok = ref_iterator_abort(iter->iter0);
783
3bc581b9
MH
784 base_ref_iterator_free(ref_iterator);
785 return ok;
786}
787
788static struct ref_iterator_vtable files_ref_iterator_vtable = {
789 files_ref_iterator_advance,
790 files_ref_iterator_peel,
791 files_ref_iterator_abort
792};
793
1a769003 794static struct ref_iterator *files_ref_iterator_begin(
37b6f6d5 795 struct ref_store *ref_store,
3bc581b9
MH
796 const char *prefix, unsigned int flags)
797{
9e7ec634 798 struct files_ref_store *refs;
8738a8a4 799 struct ref_iterator *loose_iter, *packed_iter, *overlay_iter;
3bc581b9
MH
800 struct files_ref_iterator *iter;
801 struct ref_iterator *ref_iterator;
0a0865b8 802 unsigned int required_flags = REF_STORE_READ;
3bc581b9 803
0a0865b8
MH
804 if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
805 required_flags |= REF_STORE_ODB;
3bc581b9 806
0a0865b8 807 refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
9e7ec634 808
3bc581b9
MH
809 /*
810 * We must make sure that all loose refs are read before
811 * accessing the packed-refs file; this avoids a race
812 * condition if loose refs are migrated to the packed-refs
813 * file by a simultaneous process, but our in-memory view is
814 * from before the migration. We ensure this as follows:
059ae35a
MH
815 * First, we call start the loose refs iteration with its
816 * `prime_ref` argument set to true. This causes the loose
817 * references in the subtree to be pre-read into the cache.
818 * (If they've already been read, that's OK; we only need to
819 * guarantee that they're read before the packed refs, not
820 * *how much* before.) After that, we call
38b86e81
MH
821 * packed_ref_iterator_begin(), which internally checks
822 * whether the packed-ref cache is up to date with what is on
823 * disk, and re-reads it if not.
3bc581b9
MH
824 */
825
059ae35a
MH
826 loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
827 prefix, 1);
3bc581b9 828
38b86e81
MH
829 /*
830 * The packed-refs file might contain broken references, for
831 * example an old version of a reference that points at an
832 * object that has since been garbage-collected. This is OK as
833 * long as there is a corresponding loose reference that
834 * overrides it, and we don't want to emit an error message in
835 * this case. So ask the packed_ref_store for all of its
836 * references, and (if needed) do our own check for broken
837 * ones in files_ref_iterator_advance(), after we have merged
838 * the packed and loose references.
839 */
e0cc8ac8
MH
840 packed_iter = refs_ref_iterator_begin(
841 refs->packed_ref_store, prefix, 0,
38b86e81 842 DO_FOR_EACH_INCLUDE_BROKEN);
3bc581b9 843
8738a8a4
MH
844 overlay_iter = overlay_ref_iterator_begin(loose_iter, packed_iter);
845
846 iter = xcalloc(1, sizeof(*iter));
847 ref_iterator = &iter->base;
848 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable,
849 overlay_iter->ordered);
850 iter->iter0 = overlay_iter;
3bc581b9
MH
851 iter->flags = flags;
852
853 return ref_iterator;
7bd9bcf3
MH
854}
855
7bd9bcf3 856/*
4f01e508 857 * Verify that the reference locked by lock has the value old_oid
858 * (unless it is NULL). Fail if the reference doesn't exist and
859 * mustexist is set. Return 0 on success. On error, write an error
860 * message to err, set errno, and return a negative value.
7bd9bcf3 861 */
2f40e954 862static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
4f01e508 863 const struct object_id *old_oid, int mustexist,
7bd9bcf3
MH
864 struct strbuf *err)
865{
866 assert(err);
867
2f40e954
NTND
868 if (refs_read_ref_full(ref_store, lock->ref_name,
869 mustexist ? RESOLVE_REF_READING : 0,
34c290a6 870 &lock->old_oid, NULL)) {
4f01e508 871 if (old_oid) {
6294dcb4 872 int save_errno = errno;
0568c8e9 873 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
6294dcb4
JK
874 errno = save_errno;
875 return -1;
876 } else {
c368dde9 877 oidclr(&lock->old_oid);
6294dcb4
JK
878 return 0;
879 }
7bd9bcf3 880 }
9001dc2a 881 if (old_oid && !oideq(&lock->old_oid, old_oid)) {
0568c8e9 882 strbuf_addf(err, "ref '%s' is at %s but expected %s",
7bd9bcf3 883 lock->ref_name,
c368dde9 884 oid_to_hex(&lock->old_oid),
4f01e508 885 oid_to_hex(old_oid));
7bd9bcf3
MH
886 errno = EBUSY;
887 return -1;
888 }
889 return 0;
890}
891
892static int remove_empty_directories(struct strbuf *path)
893{
894 /*
895 * we want to create a file but there is a directory there;
896 * if that is an empty directory (or a directory that contains
897 * only empty directories), remove them.
898 */
899 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
900}
901
3b5d3c98
MH
902static int create_reflock(const char *path, void *cb)
903{
904 struct lock_file *lk = cb;
905
4ff0f01c
MH
906 return hold_lock_file_for_update_timeout(
907 lk, path, LOCK_NO_DEREF,
908 get_files_ref_lock_timeout_ms()) < 0 ? -1 : 0;
3b5d3c98
MH
909}
910
7bd9bcf3
MH
911/*
912 * Locks a ref returning the lock on success and NULL on failure.
913 * On failure errno is set to something meaningful.
914 */
4f01e508 915static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
916 const char *refname,
917 const struct object_id *old_oid,
918 const struct string_list *extras,
919 const struct string_list *skip,
920 unsigned int flags, int *type,
921 struct strbuf *err)
7bd9bcf3
MH
922{
923 struct strbuf ref_file = STRBUF_INIT;
7bd9bcf3
MH
924 struct ref_lock *lock;
925 int last_errno = 0;
4f01e508 926 int mustexist = (old_oid && !is_null_oid(old_oid));
7a418f3a 927 int resolve_flags = RESOLVE_REF_NO_RECURSE;
7a418f3a 928 int resolved;
7bd9bcf3 929
4f01e508 930 files_assert_main_repository(refs, "lock_ref_oid_basic");
7bd9bcf3
MH
931 assert(err);
932
933 lock = xcalloc(1, sizeof(struct ref_lock));
934
935 if (mustexist)
936 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 937 if (flags & REF_DELETING)
7bd9bcf3 938 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
7bd9bcf3 939
19e02f4f 940 files_ref_path(refs, &ref_file, refname);
2f40e954
NTND
941 resolved = !!refs_resolve_ref_unsafe(&refs->base,
942 refname, resolve_flags,
49e61479 943 &lock->old_oid, type);
7a418f3a 944 if (!resolved && errno == EISDIR) {
7bd9bcf3
MH
945 /*
946 * we are trying to lock foo but we used to
947 * have foo/bar which now does not exist;
948 * it is normal for the empty directory 'foo'
949 * to remain.
950 */
7a418f3a 951 if (remove_empty_directories(&ref_file)) {
7bd9bcf3 952 last_errno = errno;
b05855b5
MH
953 if (!refs_verify_refname_available(
954 &refs->base,
955 refname, extras, skip, err))
7bd9bcf3 956 strbuf_addf(err, "there are still refs under '%s'",
7a418f3a 957 refname);
7bd9bcf3
MH
958 goto error_return;
959 }
2f40e954
NTND
960 resolved = !!refs_resolve_ref_unsafe(&refs->base,
961 refname, resolve_flags,
49e61479 962 &lock->old_oid, type);
7bd9bcf3 963 }
7a418f3a 964 if (!resolved) {
7bd9bcf3
MH
965 last_errno = errno;
966 if (last_errno != ENOTDIR ||
b05855b5
MH
967 !refs_verify_refname_available(&refs->base, refname,
968 extras, skip, err))
0568c8e9 969 strbuf_addf(err, "unable to resolve reference '%s': %s",
7a418f3a 970 refname, strerror(last_errno));
7bd9bcf3
MH
971
972 goto error_return;
973 }
2859dcd4 974
7bd9bcf3
MH
975 /*
976 * If the ref did not exist and we are creating it, make sure
977 * there is no existing packed ref whose name begins with our
978 * refname, nor a packed ref whose name is a proper prefix of
979 * our refname.
980 */
981 if (is_null_oid(&lock->old_oid) &&
8ec617c8 982 refs_verify_refname_available(refs->packed_ref_store, refname,
524a9fdb 983 extras, skip, err)) {
7bd9bcf3
MH
984 last_errno = ENOTDIR;
985 goto error_return;
986 }
987
7bd9bcf3 988 lock->ref_name = xstrdup(refname);
7bd9bcf3 989
ee4d8e45 990 if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) {
7bd9bcf3 991 last_errno = errno;
3b5d3c98 992 unable_to_lock_message(ref_file.buf, errno, err);
7bd9bcf3
MH
993 goto error_return;
994 }
995
4f01e508 996 if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) {
7bd9bcf3
MH
997 last_errno = errno;
998 goto error_return;
999 }
1000 goto out;
1001
1002 error_return:
1003 unlock_ref(lock);
1004 lock = NULL;
1005
1006 out:
1007 strbuf_release(&ref_file);
7bd9bcf3
MH
1008 errno = last_errno;
1009 return lock;
1010}
1011
7bd9bcf3
MH
1012struct ref_to_prune {
1013 struct ref_to_prune *next;
49e99588 1014 struct object_id oid;
7bd9bcf3
MH
1015 char name[FLEX_ARRAY];
1016};
1017
a8f0db2d
MH
1018enum {
1019 REMOVE_EMPTY_PARENTS_REF = 0x01,
1020 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
1021};
1022
7bd9bcf3 1023/*
a8f0db2d
MH
1024 * Remove empty parent directories associated with the specified
1025 * reference and/or its reflog, but spare [logs/]refs/ and immediate
1026 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
1027 * REMOVE_EMPTY_PARENTS_REFLOG.
7bd9bcf3 1028 */
802de3da
NTND
1029static void try_remove_empty_parents(struct files_ref_store *refs,
1030 const char *refname,
1031 unsigned int flags)
7bd9bcf3 1032{
8bdaecb4 1033 struct strbuf buf = STRBUF_INIT;
e9dcc305 1034 struct strbuf sb = STRBUF_INIT;
7bd9bcf3
MH
1035 char *p, *q;
1036 int i;
8bdaecb4
MH
1037
1038 strbuf_addstr(&buf, refname);
1039 p = buf.buf;
7bd9bcf3
MH
1040 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
1041 while (*p && *p != '/')
1042 p++;
1043 /* tolerate duplicate slashes; see check_refname_format() */
1044 while (*p == '/')
1045 p++;
1046 }
8bdaecb4 1047 q = buf.buf + buf.len;
a8f0db2d 1048 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
7bd9bcf3
MH
1049 while (q > p && *q != '/')
1050 q--;
1051 while (q > p && *(q-1) == '/')
1052 q--;
1053 if (q == p)
1054 break;
8bdaecb4 1055 strbuf_setlen(&buf, q - buf.buf);
e9dcc305
NTND
1056
1057 strbuf_reset(&sb);
19e02f4f 1058 files_ref_path(refs, &sb, buf.buf);
e9dcc305 1059 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
a8f0db2d 1060 flags &= ~REMOVE_EMPTY_PARENTS_REF;
e9dcc305
NTND
1061
1062 strbuf_reset(&sb);
802de3da 1063 files_reflog_path(refs, &sb, buf.buf);
e9dcc305 1064 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
a8f0db2d 1065 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
7bd9bcf3 1066 }
8bdaecb4 1067 strbuf_release(&buf);
e9dcc305 1068 strbuf_release(&sb);
7bd9bcf3
MH
1069}
1070
1071/* make sure nobody touched the ref, and unlink */
2f40e954 1072static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
7bd9bcf3
MH
1073{
1074 struct ref_transaction *transaction;
1075 struct strbuf err = STRBUF_INIT;
b00f3cfa 1076 int ret = -1;
7bd9bcf3
MH
1077
1078 if (check_refname_format(r->name, 0))
1079 return;
1080
2f40e954 1081 transaction = ref_store_transaction_begin(&refs->base, &err);
b00f3cfa
MH
1082 if (!transaction)
1083 goto cleanup;
1084 ref_transaction_add_update(
1085 transaction, r->name,
acedcde7 1086 REF_NO_DEREF | REF_HAVE_NEW | REF_HAVE_OLD | REF_IS_PRUNING,
b00f3cfa
MH
1087 &null_oid, &r->oid, NULL);
1088 if (ref_transaction_commit(transaction, &err))
1089 goto cleanup;
1090
1091 ret = 0;
1092
1093cleanup:
1094 if (ret)
7bd9bcf3 1095 error("%s", err.buf);
7bd9bcf3 1096 strbuf_release(&err);
b00f3cfa
MH
1097 ref_transaction_free(transaction);
1098 return;
7bd9bcf3
MH
1099}
1100
22b09cdf
MH
1101/*
1102 * Prune the loose versions of the references in the linked list
1103 * `*refs_to_prune`, freeing the entries in the list as we go.
1104 */
1105static void prune_refs(struct files_ref_store *refs, struct ref_to_prune **refs_to_prune)
7bd9bcf3 1106{
22b09cdf
MH
1107 while (*refs_to_prune) {
1108 struct ref_to_prune *r = *refs_to_prune;
1109 *refs_to_prune = r->next;
2f40e954 1110 prune_ref(refs, r);
22b09cdf 1111 free(r);
7bd9bcf3
MH
1112 }
1113}
1114
531cc4a5
MH
1115/*
1116 * Return true if the specified reference should be packed.
1117 */
1118static int should_pack_ref(const char *refname,
1119 const struct object_id *oid, unsigned int ref_flags,
1120 unsigned int pack_flags)
1121{
1122 /* Do not pack per-worktree refs: */
1123 if (ref_type(refname) != REF_TYPE_NORMAL)
1124 return 0;
1125
1126 /* Do not pack non-tags unless PACK_REFS_ALL is set: */
1127 if (!(pack_flags & PACK_REFS_ALL) && !starts_with(refname, "refs/tags/"))
1128 return 0;
1129
1130 /* Do not pack symbolic refs: */
1131 if (ref_flags & REF_ISSYMREF)
1132 return 0;
1133
1134 /* Do not pack broken refs: */
1135 if (!ref_resolves_to_object(refname, oid, ref_flags))
1136 return 0;
1137
1138 return 1;
1139}
1140
8231527e 1141static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
7bd9bcf3 1142{
00eebe35 1143 struct files_ref_store *refs =
9e7ec634
NTND
1144 files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
1145 "pack_refs");
50c2d855 1146 struct ref_iterator *iter;
50c2d855
MH
1147 int ok;
1148 struct ref_to_prune *refs_to_prune = NULL;
3478983b 1149 struct strbuf err = STRBUF_INIT;
27d03d04
MH
1150 struct ref_transaction *transaction;
1151
1152 transaction = ref_store_transaction_begin(refs->packed_ref_store, &err);
1153 if (!transaction)
1154 return -1;
7bd9bcf3 1155
c8bed835 1156 packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
50c2d855
MH
1157
1158 iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
1159 while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1160 /*
1161 * If the loose reference can be packed, add an entry
1162 * in the packed ref cache. If the reference should be
1163 * pruned, also add it to refs_to_prune.
1164 */
531cc4a5
MH
1165 if (!should_pack_ref(iter->refname, iter->oid, iter->flags,
1166 flags))
50c2d855
MH
1167 continue;
1168
1169 /*
27d03d04
MH
1170 * Add a reference creation for this reference to the
1171 * packed-refs transaction:
50c2d855 1172 */
27d03d04 1173 if (ref_transaction_update(transaction, iter->refname,
89f3bbdd 1174 iter->oid, NULL,
91774afc 1175 REF_NO_DEREF, NULL, &err))
27d03d04
MH
1176 die("failure preparing to create packed reference %s: %s",
1177 iter->refname, err.buf);
50c2d855
MH
1178
1179 /* Schedule the loose reference for pruning if requested. */
1180 if ((flags & PACK_REFS_PRUNE)) {
1181 struct ref_to_prune *n;
1182 FLEX_ALLOC_STR(n, name, iter->refname);
49e99588 1183 oidcpy(&n->oid, iter->oid);
50c2d855
MH
1184 n->next = refs_to_prune;
1185 refs_to_prune = n;
1186 }
1187 }
1188 if (ok != ITER_DONE)
1189 die("error while iterating over references");
7bd9bcf3 1190
27d03d04
MH
1191 if (ref_transaction_commit(transaction, &err))
1192 die("unable to write new packed-refs: %s", err.buf);
1193
1194 ref_transaction_free(transaction);
1195
42c7f7ff 1196 packed_refs_unlock(refs->packed_ref_store);
7bd9bcf3 1197
22b09cdf 1198 prune_refs(refs, &refs_to_prune);
3478983b 1199 strbuf_release(&err);
7bd9bcf3
MH
1200 return 0;
1201}
1202
64da4199 1203static int files_delete_refs(struct ref_store *ref_store, const char *msg,
a27dcf89 1204 struct string_list *refnames, unsigned int flags)
7bd9bcf3 1205{
0a95ac5f 1206 struct files_ref_store *refs =
9e7ec634 1207 files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
7bd9bcf3
MH
1208 struct strbuf err = STRBUF_INIT;
1209 int i, result = 0;
1210
1211 if (!refnames->nr)
1212 return 0;
1213
e5cc7d7d
MH
1214 if (packed_refs_lock(refs->packed_ref_store, 0, &err))
1215 goto error;
7bd9bcf3 1216
2fb330ca 1217 if (refs_delete_refs(refs->packed_ref_store, msg, refnames, flags)) {
e5cc7d7d
MH
1218 packed_refs_unlock(refs->packed_ref_store);
1219 goto error;
7bd9bcf3
MH
1220 }
1221
e5cc7d7d
MH
1222 packed_refs_unlock(refs->packed_ref_store);
1223
7bd9bcf3
MH
1224 for (i = 0; i < refnames->nr; i++) {
1225 const char *refname = refnames->items[i].string;
1226
64da4199 1227 if (refs_delete_ref(&refs->base, msg, refname, NULL, flags))
7bd9bcf3
MH
1228 result |= error(_("could not remove reference %s"), refname);
1229 }
1230
7bd9bcf3
MH
1231 strbuf_release(&err);
1232 return result;
e5cc7d7d
MH
1233
1234error:
1235 /*
1236 * If we failed to rewrite the packed-refs file, then it is
1237 * unsafe to try to remove loose refs, because doing so might
1238 * expose an obsolete packed value for a reference that might
1239 * even point at an object that has been garbage collected.
1240 */
1241 if (refnames->nr == 1)
1242 error(_("could not delete reference %s: %s"),
1243 refnames->items[0].string, err.buf);
1244 else
1245 error(_("could not delete references: %s"), err.buf);
1246
1247 strbuf_release(&err);
1248 return -1;
7bd9bcf3
MH
1249}
1250
1251/*
1252 * People using contrib's git-new-workdir have .git/logs/refs ->
1253 * /some/other/path/.git/logs/refs, and that may live on another device.
1254 *
1255 * IOW, to avoid cross device rename errors, the temporary renamed log must
1256 * live into logs/refs.
1257 */
a5c1efd6 1258#define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
7bd9bcf3 1259
e9dcc305
NTND
1260struct rename_cb {
1261 const char *tmp_renamed_log;
1262 int true_errno;
1263};
1264
1265static int rename_tmp_log_callback(const char *path, void *cb_data)
7bd9bcf3 1266{
e9dcc305 1267 struct rename_cb *cb = cb_data;
7bd9bcf3 1268
e9dcc305 1269 if (rename(cb->tmp_renamed_log, path)) {
6a7f3631
MH
1270 /*
1271 * rename(a, b) when b is an existing directory ought
1272 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
1273 * Sheesh. Record the true errno for error reporting,
1274 * but report EISDIR to raceproof_create_file() so
1275 * that it knows to retry.
1276 */
e9dcc305 1277 cb->true_errno = errno;
6a7f3631
MH
1278 if (errno == ENOTDIR)
1279 errno = EISDIR;
1280 return -1;
1281 } else {
1282 return 0;
7bd9bcf3 1283 }
6a7f3631 1284}
7bd9bcf3 1285
802de3da 1286static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
6a7f3631 1287{
e9dcc305
NTND
1288 struct strbuf path = STRBUF_INIT;
1289 struct strbuf tmp = STRBUF_INIT;
1290 struct rename_cb cb;
1291 int ret;
6a7f3631 1292
802de3da
NTND
1293 files_reflog_path(refs, &path, newrefname);
1294 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
e9dcc305
NTND
1295 cb.tmp_renamed_log = tmp.buf;
1296 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
6a7f3631
MH
1297 if (ret) {
1298 if (errno == EISDIR)
e9dcc305 1299 error("directory not empty: %s", path.buf);
6a7f3631 1300 else
990c98d2 1301 error("unable to move logfile %s to %s: %s",
e9dcc305
NTND
1302 tmp.buf, path.buf,
1303 strerror(cb.true_errno));
7bd9bcf3 1304 }
6a7f3631 1305
e9dcc305
NTND
1306 strbuf_release(&path);
1307 strbuf_release(&tmp);
7bd9bcf3
MH
1308 return ret;
1309}
1310
7bd9bcf3 1311static int write_ref_to_lockfile(struct ref_lock *lock,
4417df8c 1312 const struct object_id *oid, struct strbuf *err);
f18a7892
MH
1313static int commit_ref_update(struct files_ref_store *refs,
1314 struct ref_lock *lock,
4417df8c 1315 const struct object_id *oid, const char *logmsg,
5d9b2de4 1316 struct strbuf *err);
7bd9bcf3 1317
52d59cc6 1318static int files_copy_or_rename_ref(struct ref_store *ref_store,
9b6b40d9 1319 const char *oldrefname, const char *newrefname,
52d59cc6 1320 const char *logmsg, int copy)
7bd9bcf3 1321{
9b6b40d9 1322 struct files_ref_store *refs =
9e7ec634 1323 files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
4417df8c 1324 struct object_id oid, orig_oid;
7bd9bcf3
MH
1325 int flag = 0, logmoved = 0;
1326 struct ref_lock *lock;
1327 struct stat loginfo;
e9dcc305
NTND
1328 struct strbuf sb_oldref = STRBUF_INIT;
1329 struct strbuf sb_newref = STRBUF_INIT;
1330 struct strbuf tmp_renamed_log = STRBUF_INIT;
1331 int log, ret;
7bd9bcf3
MH
1332 struct strbuf err = STRBUF_INIT;
1333
802de3da
NTND
1334 files_reflog_path(refs, &sb_oldref, oldrefname);
1335 files_reflog_path(refs, &sb_newref, newrefname);
1336 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
e9dcc305
NTND
1337
1338 log = !lstat(sb_oldref.buf, &loginfo);
0a3f07d6
NTND
1339 if (log && S_ISLNK(loginfo.st_mode)) {
1340 ret = error("reflog for %s is a symlink", oldrefname);
1341 goto out;
1342 }
7bd9bcf3 1343
2f40e954
NTND
1344 if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
1345 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
49e61479 1346 &orig_oid, &flag)) {
0a3f07d6
NTND
1347 ret = error("refname %s not found", oldrefname);
1348 goto out;
1349 }
e711b1af 1350
0a3f07d6 1351 if (flag & REF_ISSYMREF) {
52d59cc6
SD
1352 if (copy)
1353 ret = error("refname %s is a symbolic ref, copying it is not supported",
1354 oldrefname);
1355 else
1356 ret = error("refname %s is a symbolic ref, renaming it is not supported",
1357 oldrefname);
0a3f07d6
NTND
1358 goto out;
1359 }
7d2df051 1360 if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
0a3f07d6
NTND
1361 ret = 1;
1362 goto out;
1363 }
7bd9bcf3 1364
52d59cc6 1365 if (!copy && log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
a5c1efd6 1366 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
0a3f07d6
NTND
1367 oldrefname, strerror(errno));
1368 goto out;
1369 }
7bd9bcf3 1370
52d59cc6
SD
1371 if (copy && log && copy_file(tmp_renamed_log.buf, sb_oldref.buf, 0644)) {
1372 ret = error("unable to copy logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
1373 oldrefname, strerror(errno));
1374 goto out;
1375 }
1376
1377 if (!copy && refs_delete_ref(&refs->base, logmsg, oldrefname,
91774afc 1378 &orig_oid, REF_NO_DEREF)) {
7bd9bcf3
MH
1379 error("unable to delete old %s", oldrefname);
1380 goto rollback;
1381 }
1382
12fd3496 1383 /*
4417df8c 1384 * Since we are doing a shallow lookup, oid is not the
1385 * correct value to pass to delete_ref as old_oid. But that
1386 * doesn't matter, because an old_oid check wouldn't add to
12fd3496
DT
1387 * the safety anyway; we want to delete the reference whatever
1388 * its current value.
1389 */
52d59cc6 1390 if (!copy && !refs_read_ref_full(&refs->base, newrefname,
2f40e954 1391 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
34c290a6 1392 &oid, NULL) &&
2f40e954 1393 refs_delete_ref(&refs->base, NULL, newrefname,
91774afc 1394 NULL, REF_NO_DEREF)) {
58364324 1395 if (errno == EISDIR) {
7bd9bcf3
MH
1396 struct strbuf path = STRBUF_INIT;
1397 int result;
1398
19e02f4f 1399 files_ref_path(refs, &path, newrefname);
7bd9bcf3
MH
1400 result = remove_empty_directories(&path);
1401 strbuf_release(&path);
1402
1403 if (result) {
1404 error("Directory not empty: %s", newrefname);
1405 goto rollback;
1406 }
1407 } else {
1408 error("unable to delete existing %s", newrefname);
1409 goto rollback;
1410 }
1411 }
1412
802de3da 1413 if (log && rename_tmp_log(refs, newrefname))
7bd9bcf3
MH
1414 goto rollback;
1415
1416 logmoved = log;
1417
4f01e508 1418 lock = lock_ref_oid_basic(refs, newrefname, NULL, NULL, NULL,
91774afc 1419 REF_NO_DEREF, NULL, &err);
7bd9bcf3 1420 if (!lock) {
52d59cc6
SD
1421 if (copy)
1422 error("unable to copy '%s' to '%s': %s", oldrefname, newrefname, err.buf);
1423 else
1424 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
7bd9bcf3
MH
1425 strbuf_release(&err);
1426 goto rollback;
1427 }
4417df8c 1428 oidcpy(&lock->old_oid, &orig_oid);
7bd9bcf3 1429
4417df8c 1430 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1431 commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) {
7bd9bcf3
MH
1432 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
1433 strbuf_release(&err);
1434 goto rollback;
1435 }
1436
0a3f07d6
NTND
1437 ret = 0;
1438 goto out;
7bd9bcf3
MH
1439
1440 rollback:
4f01e508 1441 lock = lock_ref_oid_basic(refs, oldrefname, NULL, NULL, NULL,
91774afc 1442 REF_NO_DEREF, NULL, &err);
7bd9bcf3
MH
1443 if (!lock) {
1444 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
1445 strbuf_release(&err);
1446 goto rollbacklog;
1447 }
1448
1449 flag = log_all_ref_updates;
341fb286 1450 log_all_ref_updates = LOG_REFS_NONE;
4417df8c 1451 if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
1452 commit_ref_update(refs, lock, &orig_oid, NULL, &err)) {
7bd9bcf3
MH
1453 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
1454 strbuf_release(&err);
1455 }
1456 log_all_ref_updates = flag;
1457
1458 rollbacklog:
e9dcc305 1459 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
7bd9bcf3
MH
1460 error("unable to restore logfile %s from %s: %s",
1461 oldrefname, newrefname, strerror(errno));
1462 if (!logmoved && log &&
e9dcc305 1463 rename(tmp_renamed_log.buf, sb_oldref.buf))
a5c1efd6 1464 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
7bd9bcf3 1465 oldrefname, strerror(errno));
0a3f07d6
NTND
1466 ret = 1;
1467 out:
e9dcc305
NTND
1468 strbuf_release(&sb_newref);
1469 strbuf_release(&sb_oldref);
1470 strbuf_release(&tmp_renamed_log);
1471
0a3f07d6 1472 return ret;
7bd9bcf3
MH
1473}
1474
52d59cc6
SD
1475static int files_rename_ref(struct ref_store *ref_store,
1476 const char *oldrefname, const char *newrefname,
1477 const char *logmsg)
1478{
1479 return files_copy_or_rename_ref(ref_store, oldrefname,
1480 newrefname, logmsg, 0);
1481}
1482
1483static int files_copy_ref(struct ref_store *ref_store,
1484 const char *oldrefname, const char *newrefname,
1485 const char *logmsg)
1486{
1487 return files_copy_or_rename_ref(ref_store, oldrefname,
1488 newrefname, logmsg, 1);
1489}
1490
83a3069a 1491static int close_ref_gently(struct ref_lock *lock)
7bd9bcf3 1492{
ee4d8e45 1493 if (close_lock_file_gently(&lock->lk))
7bd9bcf3
MH
1494 return -1;
1495 return 0;
1496}
1497
1498static int commit_ref(struct ref_lock *lock)
1499{
ee4d8e45 1500 char *path = get_locked_file_path(&lock->lk);
5387c0d8
MH
1501 struct stat st;
1502
1503 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
1504 /*
1505 * There is a directory at the path we want to rename
1506 * the lockfile to. Hopefully it is empty; try to
1507 * delete it.
1508 */
1509 size_t len = strlen(path);
1510 struct strbuf sb_path = STRBUF_INIT;
1511
1512 strbuf_attach(&sb_path, path, len, len);
1513
1514 /*
1515 * If this fails, commit_lock_file() will also fail
1516 * and will report the problem.
1517 */
1518 remove_empty_directories(&sb_path);
1519 strbuf_release(&sb_path);
1520 } else {
1521 free(path);
1522 }
1523
ee4d8e45 1524 if (commit_lock_file(&lock->lk))
7bd9bcf3
MH
1525 return -1;
1526 return 0;
1527}
1528
1fb0c809
MH
1529static int open_or_create_logfile(const char *path, void *cb)
1530{
1531 int *fd = cb;
1532
1533 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
1534 return (*fd < 0) ? -1 : 0;
1535}
1536
7bd9bcf3 1537/*
4533e534
MH
1538 * Create a reflog for a ref. If force_create = 0, only create the
1539 * reflog for certain refs (those for which should_autocreate_reflog
1540 * returns non-zero). Otherwise, create it regardless of the reference
1541 * name. If the logfile already existed or was created, return 0 and
1542 * set *logfd to the file descriptor opened for appending to the file.
1543 * If no logfile exists and we decided not to create one, return 0 and
1544 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
1545 * return -1.
7bd9bcf3 1546 */
802de3da
NTND
1547static int log_ref_setup(struct files_ref_store *refs,
1548 const char *refname, int force_create,
4533e534 1549 int *logfd, struct strbuf *err)
7bd9bcf3 1550{
802de3da
NTND
1551 struct strbuf logfile_sb = STRBUF_INIT;
1552 char *logfile;
1553
1554 files_reflog_path(refs, &logfile_sb, refname);
1555 logfile = strbuf_detach(&logfile_sb, NULL);
7bd9bcf3 1556
7bd9bcf3 1557 if (force_create || should_autocreate_reflog(refname)) {
4533e534 1558 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1fb0c809
MH
1559 if (errno == ENOENT)
1560 strbuf_addf(err, "unable to create directory for '%s': "
4533e534 1561 "%s", logfile, strerror(errno));
1fb0c809
MH
1562 else if (errno == EISDIR)
1563 strbuf_addf(err, "there are still logs under '%s'",
4533e534 1564 logfile);
1fb0c809 1565 else
854bda6b 1566 strbuf_addf(err, "unable to append to '%s': %s",
4533e534 1567 logfile, strerror(errno));
7bd9bcf3 1568
4533e534 1569 goto error;
7bd9bcf3 1570 }
854bda6b 1571 } else {
4533e534 1572 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
e404f459 1573 if (*logfd < 0) {
854bda6b
MH
1574 if (errno == ENOENT || errno == EISDIR) {
1575 /*
1576 * The logfile doesn't already exist,
1577 * but that is not an error; it only
1578 * means that we won't write log
1579 * entries to it.
1580 */
1581 ;
1582 } else {
1583 strbuf_addf(err, "unable to append to '%s': %s",
4533e534
MH
1584 logfile, strerror(errno));
1585 goto error;
854bda6b 1586 }
7bd9bcf3
MH
1587 }
1588 }
1589
e404f459 1590 if (*logfd >= 0)
4533e534 1591 adjust_shared_perm(logfile);
854bda6b 1592
4533e534 1593 free(logfile);
7bd9bcf3 1594 return 0;
7bd9bcf3 1595
4533e534
MH
1596error:
1597 free(logfile);
1598 return -1;
7bd9bcf3 1599}
7bd9bcf3 1600
e3688bd6
DT
1601static int files_create_reflog(struct ref_store *ref_store,
1602 const char *refname, int force_create,
1603 struct strbuf *err)
7bd9bcf3 1604{
802de3da 1605 struct files_ref_store *refs =
9e7ec634 1606 files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
e404f459 1607 int fd;
7bd9bcf3 1608
802de3da 1609 if (log_ref_setup(refs, refname, force_create, &fd, err))
4533e534
MH
1610 return -1;
1611
e404f459
MH
1612 if (fd >= 0)
1613 close(fd);
4533e534
MH
1614
1615 return 0;
7bd9bcf3
MH
1616}
1617
4417df8c 1618static int log_ref_write_fd(int fd, const struct object_id *old_oid,
1619 const struct object_id *new_oid,
7bd9bcf3
MH
1620 const char *committer, const char *msg)
1621{
80a6c207
BP
1622 struct strbuf sb = STRBUF_INIT;
1623 int ret = 0;
1624
1625 strbuf_addf(&sb, "%s %s %s", oid_to_hex(old_oid), oid_to_hex(new_oid), committer);
1626 if (msg && *msg)
1627 copy_reflog_msg(&sb, msg);
1628 strbuf_addch(&sb, '\n');
1629 if (write_in_full(fd, sb.buf, sb.len) < 0)
1630 ret = -1;
1631 strbuf_release(&sb);
1632 return ret;
7bd9bcf3
MH
1633}
1634
802de3da 1635static int files_log_ref_write(struct files_ref_store *refs,
4417df8c 1636 const char *refname, const struct object_id *old_oid,
1637 const struct object_id *new_oid, const char *msg,
11f8457f 1638 int flags, struct strbuf *err)
7bd9bcf3 1639{
e404f459 1640 int logfd, result;
7bd9bcf3 1641
341fb286
CW
1642 if (log_all_ref_updates == LOG_REFS_UNSET)
1643 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
7bd9bcf3 1644
802de3da
NTND
1645 result = log_ref_setup(refs, refname,
1646 flags & REF_FORCE_CREATE_REFLOG,
4533e534 1647 &logfd, err);
7bd9bcf3
MH
1648
1649 if (result)
1650 return result;
1651
7bd9bcf3
MH
1652 if (logfd < 0)
1653 return 0;
4417df8c 1654 result = log_ref_write_fd(logfd, old_oid, new_oid,
7bd9bcf3
MH
1655 git_committer_info(0), msg);
1656 if (result) {
e9dcc305 1657 struct strbuf sb = STRBUF_INIT;
87b21e05
MH
1658 int save_errno = errno;
1659
802de3da 1660 files_reflog_path(refs, &sb, refname);
87b21e05 1661 strbuf_addf(err, "unable to append to '%s': %s",
e9dcc305
NTND
1662 sb.buf, strerror(save_errno));
1663 strbuf_release(&sb);
7bd9bcf3
MH
1664 close(logfd);
1665 return -1;
1666 }
1667 if (close(logfd)) {
e9dcc305 1668 struct strbuf sb = STRBUF_INIT;
87b21e05
MH
1669 int save_errno = errno;
1670
802de3da 1671 files_reflog_path(refs, &sb, refname);
87b21e05 1672 strbuf_addf(err, "unable to append to '%s': %s",
e9dcc305
NTND
1673 sb.buf, strerror(save_errno));
1674 strbuf_release(&sb);
7bd9bcf3
MH
1675 return -1;
1676 }
1677 return 0;
1678}
1679
7bd9bcf3 1680/*
78fb4579
MH
1681 * Write oid into the open lockfile, then close the lockfile. On
1682 * errors, rollback the lockfile, fill in *err and return -1.
7bd9bcf3
MH
1683 */
1684static int write_ref_to_lockfile(struct ref_lock *lock,
4417df8c 1685 const struct object_id *oid, struct strbuf *err)
7bd9bcf3
MH
1686{
1687 static char term = '\n';
1688 struct object *o;
1689 int fd;
1690
109cd76d 1691 o = parse_object(the_repository, oid);
7bd9bcf3
MH
1692 if (!o) {
1693 strbuf_addf(err,
0568c8e9 1694 "trying to write ref '%s' with nonexistent object %s",
4417df8c 1695 lock->ref_name, oid_to_hex(oid));
7bd9bcf3
MH
1696 unlock_ref(lock);
1697 return -1;
1698 }
1699 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1700 strbuf_addf(err,
0568c8e9 1701 "trying to write non-commit object %s to branch '%s'",
4417df8c 1702 oid_to_hex(oid), lock->ref_name);
7bd9bcf3
MH
1703 unlock_ref(lock);
1704 return -1;
1705 }
ee4d8e45 1706 fd = get_lock_file_fd(&lock->lk);
2ae2e2a1 1707 if (write_in_full(fd, oid_to_hex(oid), the_hash_algo->hexsz) < 0 ||
06f46f23 1708 write_in_full(fd, &term, 1) < 0 ||
83a3069a 1709 close_ref_gently(lock) < 0) {
7bd9bcf3 1710 strbuf_addf(err,
ee4d8e45 1711 "couldn't write '%s'", get_lock_file_path(&lock->lk));
7bd9bcf3
MH
1712 unlock_ref(lock);
1713 return -1;
1714 }
1715 return 0;
1716}
1717
1718/*
1719 * Commit a change to a loose reference that has already been written
1720 * to the loose reference lockfile. Also update the reflogs if
1721 * necessary, using the specified lockmsg (which can be NULL).
1722 */
f18a7892
MH
1723static int commit_ref_update(struct files_ref_store *refs,
1724 struct ref_lock *lock,
4417df8c 1725 const struct object_id *oid, const char *logmsg,
5d9b2de4 1726 struct strbuf *err)
7bd9bcf3 1727{
32c597e7 1728 files_assert_main_repository(refs, "commit_ref_update");
00eebe35
MH
1729
1730 clear_loose_ref_cache(refs);
802de3da 1731 if (files_log_ref_write(refs, lock->ref_name,
4417df8c 1732 &lock->old_oid, oid,
81b1b6d4 1733 logmsg, 0, err)) {
7bd9bcf3 1734 char *old_msg = strbuf_detach(err, NULL);
0568c8e9 1735 strbuf_addf(err, "cannot update the ref '%s': %s",
7bd9bcf3
MH
1736 lock->ref_name, old_msg);
1737 free(old_msg);
1738 unlock_ref(lock);
1739 return -1;
1740 }
7a418f3a
MH
1741
1742 if (strcmp(lock->ref_name, "HEAD") != 0) {
7bd9bcf3
MH
1743 /*
1744 * Special hack: If a branch is updated directly and HEAD
1745 * points to it (may happen on the remote side of a push
1746 * for example) then logically the HEAD reflog should be
1747 * updated too.
1748 * A generic solution implies reverse symref information,
1749 * but finding all symrefs pointing to the given branch
1750 * would be rather costly for this rare event (the direct
1751 * update of a branch) to be worth it. So let's cheat and
1752 * check with HEAD only which should cover 99% of all usage
1753 * scenarios (even 100% of the default ones).
1754 */
7bd9bcf3
MH
1755 int head_flag;
1756 const char *head_ref;
7a418f3a 1757
2f40e954
NTND
1758 head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
1759 RESOLVE_REF_READING,
e691b027 1760 NULL, &head_flag);
7bd9bcf3
MH
1761 if (head_ref && (head_flag & REF_ISSYMREF) &&
1762 !strcmp(head_ref, lock->ref_name)) {
1763 struct strbuf log_err = STRBUF_INIT;
802de3da 1764 if (files_log_ref_write(refs, "HEAD",
4417df8c 1765 &lock->old_oid, oid,
802de3da 1766 logmsg, 0, &log_err)) {
7bd9bcf3
MH
1767 error("%s", log_err.buf);
1768 strbuf_release(&log_err);
1769 }
1770 }
1771 }
7a418f3a 1772
7bd9bcf3 1773 if (commit_ref(lock)) {
0568c8e9 1774 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
7bd9bcf3
MH
1775 unlock_ref(lock);
1776 return -1;
1777 }
1778
1779 unlock_ref(lock);
1780 return 0;
1781}
1782
370e5ad6 1783static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 1784{
370e5ad6 1785 int ret = -1;
7bd9bcf3 1786#ifndef NO_SYMLINK_HEAD
ee4d8e45 1787 char *ref_path = get_locked_file_path(&lock->lk);
370e5ad6
JK
1788 unlink(ref_path);
1789 ret = symlink(target, ref_path);
1790 free(ref_path);
1791
1792 if (ret)
7bd9bcf3 1793 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 1794#endif
370e5ad6
JK
1795 return ret;
1796}
7bd9bcf3 1797
802de3da
NTND
1798static void update_symref_reflog(struct files_ref_store *refs,
1799 struct ref_lock *lock, const char *refname,
370e5ad6
JK
1800 const char *target, const char *logmsg)
1801{
1802 struct strbuf err = STRBUF_INIT;
4417df8c 1803 struct object_id new_oid;
2f40e954
NTND
1804 if (logmsg &&
1805 !refs_read_ref_full(&refs->base, target,
34c290a6 1806 RESOLVE_REF_READING, &new_oid, NULL) &&
4417df8c 1807 files_log_ref_write(refs, refname, &lock->old_oid,
1808 &new_oid, logmsg, 0, &err)) {
7bd9bcf3
MH
1809 error("%s", err.buf);
1810 strbuf_release(&err);
1811 }
370e5ad6 1812}
7bd9bcf3 1813
802de3da
NTND
1814static int create_symref_locked(struct files_ref_store *refs,
1815 struct ref_lock *lock, const char *refname,
370e5ad6
JK
1816 const char *target, const char *logmsg)
1817{
1818 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
802de3da 1819 update_symref_reflog(refs, lock, refname, target, logmsg);
370e5ad6
JK
1820 return 0;
1821 }
1822
ee4d8e45 1823 if (!fdopen_lock_file(&lock->lk, "w"))
370e5ad6 1824 return error("unable to fdopen %s: %s",
ee4d8e45 1825 lock->lk.tempfile->filename.buf, strerror(errno));
370e5ad6 1826
802de3da 1827 update_symref_reflog(refs, lock, refname, target, logmsg);
396da8f7 1828
370e5ad6 1829 /* no error check; commit_ref will check ferror */
ee4d8e45 1830 fprintf(lock->lk.tempfile->fp, "ref: %s\n", target);
370e5ad6
JK
1831 if (commit_ref(lock) < 0)
1832 return error("unable to write symref for %s: %s", refname,
1833 strerror(errno));
7bd9bcf3
MH
1834 return 0;
1835}
1836
284689ba
MH
1837static int files_create_symref(struct ref_store *ref_store,
1838 const char *refname, const char *target,
1839 const char *logmsg)
370e5ad6 1840{
7eb27cdf 1841 struct files_ref_store *refs =
9e7ec634 1842 files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
370e5ad6
JK
1843 struct strbuf err = STRBUF_INIT;
1844 struct ref_lock *lock;
1845 int ret;
1846
4f01e508 1847 lock = lock_ref_oid_basic(refs, refname, NULL,
91774afc 1848 NULL, NULL, REF_NO_DEREF, NULL,
4f01e508 1849 &err);
370e5ad6
JK
1850 if (!lock) {
1851 error("%s", err.buf);
1852 strbuf_release(&err);
1853 return -1;
1854 }
1855
802de3da 1856 ret = create_symref_locked(refs, lock, refname, target, logmsg);
370e5ad6
JK
1857 unlock_ref(lock);
1858 return ret;
1859}
1860
e3688bd6
DT
1861static int files_reflog_exists(struct ref_store *ref_store,
1862 const char *refname)
7bd9bcf3 1863{
802de3da 1864 struct files_ref_store *refs =
9e7ec634 1865 files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
e9dcc305 1866 struct strbuf sb = STRBUF_INIT;
7bd9bcf3 1867 struct stat st;
e9dcc305 1868 int ret;
7bd9bcf3 1869
802de3da 1870 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
1871 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
1872 strbuf_release(&sb);
1873 return ret;
7bd9bcf3
MH
1874}
1875
e3688bd6
DT
1876static int files_delete_reflog(struct ref_store *ref_store,
1877 const char *refname)
7bd9bcf3 1878{
802de3da 1879 struct files_ref_store *refs =
9e7ec634 1880 files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
e9dcc305
NTND
1881 struct strbuf sb = STRBUF_INIT;
1882 int ret;
1883
802de3da 1884 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
1885 ret = remove_path(sb.buf);
1886 strbuf_release(&sb);
1887 return ret;
7bd9bcf3
MH
1888}
1889
1890static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
1891{
9461d272 1892 struct object_id ooid, noid;
7bd9bcf3 1893 char *email_end, *message;
dddbad72 1894 timestamp_t timestamp;
7bd9bcf3 1895 int tz;
43bc3b6c 1896 const char *p = sb->buf;
7bd9bcf3
MH
1897
1898 /* old SP new SP name <email> SP time TAB msg LF */
43bc3b6c 1899 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
1900 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
1901 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
1902 !(email_end = strchr(p, '>')) ||
7bd9bcf3 1903 email_end[1] != ' ' ||
1aeb7e75 1904 !(timestamp = parse_timestamp(email_end + 2, &message, 10)) ||
7bd9bcf3
MH
1905 !message || message[0] != ' ' ||
1906 (message[1] != '+' && message[1] != '-') ||
1907 !isdigit(message[2]) || !isdigit(message[3]) ||
1908 !isdigit(message[4]) || !isdigit(message[5]))
1909 return 0; /* corrupt? */
1910 email_end[1] = '\0';
1911 tz = strtol(message + 1, NULL, 10);
1912 if (message[6] != '\t')
1913 message += 6;
1914 else
1915 message += 7;
43bc3b6c 1916 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
7bd9bcf3
MH
1917}
1918
1919static char *find_beginning_of_line(char *bob, char *scan)
1920{
1921 while (bob < scan && *(--scan) != '\n')
1922 ; /* keep scanning backwards */
1923 /*
1924 * Return either beginning of the buffer, or LF at the end of
1925 * the previous line.
1926 */
1927 return scan;
1928}
1929
e3688bd6
DT
1930static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
1931 const char *refname,
1932 each_reflog_ent_fn fn,
1933 void *cb_data)
7bd9bcf3 1934{
802de3da 1935 struct files_ref_store *refs =
9e7ec634
NTND
1936 files_downcast(ref_store, REF_STORE_READ,
1937 "for_each_reflog_ent_reverse");
7bd9bcf3
MH
1938 struct strbuf sb = STRBUF_INIT;
1939 FILE *logfp;
1940 long pos;
1941 int ret = 0, at_tail = 1;
1942
802de3da 1943 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
1944 logfp = fopen(sb.buf, "r");
1945 strbuf_release(&sb);
7bd9bcf3
MH
1946 if (!logfp)
1947 return -1;
1948
1949 /* Jump to the end */
1950 if (fseek(logfp, 0, SEEK_END) < 0)
be686f03
RS
1951 ret = error("cannot seek back reflog for %s: %s",
1952 refname, strerror(errno));
7bd9bcf3
MH
1953 pos = ftell(logfp);
1954 while (!ret && 0 < pos) {
1955 int cnt;
1956 size_t nread;
1957 char buf[BUFSIZ];
1958 char *endp, *scanp;
1959
1960 /* Fill next block from the end */
1961 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
be686f03
RS
1962 if (fseek(logfp, pos - cnt, SEEK_SET)) {
1963 ret = error("cannot seek back reflog for %s: %s",
1964 refname, strerror(errno));
1965 break;
1966 }
7bd9bcf3 1967 nread = fread(buf, cnt, 1, logfp);
be686f03
RS
1968 if (nread != 1) {
1969 ret = error("cannot read %d bytes from reflog for %s: %s",
1970 cnt, refname, strerror(errno));
1971 break;
1972 }
7bd9bcf3
MH
1973 pos -= cnt;
1974
1975 scanp = endp = buf + cnt;
1976 if (at_tail && scanp[-1] == '\n')
1977 /* Looking at the final LF at the end of the file */
1978 scanp--;
1979 at_tail = 0;
1980
1981 while (buf < scanp) {
1982 /*
1983 * terminating LF of the previous line, or the beginning
1984 * of the buffer.
1985 */
1986 char *bp;
1987
1988 bp = find_beginning_of_line(buf, scanp);
1989
1990 if (*bp == '\n') {
1991 /*
1992 * The newline is the end of the previous line,
1993 * so we know we have complete line starting
1994 * at (bp + 1). Prefix it onto any prior data
1995 * we collected for the line and process it.
1996 */
1997 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
1998 scanp = bp;
1999 endp = bp + 1;
2000 ret = show_one_reflog_ent(&sb, fn, cb_data);
2001 strbuf_reset(&sb);
2002 if (ret)
2003 break;
2004 } else if (!pos) {
2005 /*
2006 * We are at the start of the buffer, and the
2007 * start of the file; there is no previous
2008 * line, and we have everything for this one.
2009 * Process it, and we can end the loop.
2010 */
2011 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2012 ret = show_one_reflog_ent(&sb, fn, cb_data);
2013 strbuf_reset(&sb);
2014 break;
2015 }
2016
2017 if (bp == buf) {
2018 /*
2019 * We are at the start of the buffer, and there
2020 * is more file to read backwards. Which means
2021 * we are in the middle of a line. Note that we
2022 * may get here even if *bp was a newline; that
2023 * just means we are at the exact end of the
2024 * previous line, rather than some spot in the
2025 * middle.
2026 *
2027 * Save away what we have to be combined with
2028 * the data from the next read.
2029 */
2030 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2031 break;
2032 }
2033 }
2034
2035 }
2036 if (!ret && sb.len)
033abf97 2037 BUG("reverse reflog parser had leftover data");
7bd9bcf3
MH
2038
2039 fclose(logfp);
2040 strbuf_release(&sb);
2041 return ret;
2042}
2043
e3688bd6
DT
2044static int files_for_each_reflog_ent(struct ref_store *ref_store,
2045 const char *refname,
2046 each_reflog_ent_fn fn, void *cb_data)
7bd9bcf3 2047{
802de3da 2048 struct files_ref_store *refs =
9e7ec634
NTND
2049 files_downcast(ref_store, REF_STORE_READ,
2050 "for_each_reflog_ent");
7bd9bcf3
MH
2051 FILE *logfp;
2052 struct strbuf sb = STRBUF_INIT;
2053 int ret = 0;
2054
802de3da 2055 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
2056 logfp = fopen(sb.buf, "r");
2057 strbuf_release(&sb);
7bd9bcf3
MH
2058 if (!logfp)
2059 return -1;
2060
2061 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
2062 ret = show_one_reflog_ent(&sb, fn, cb_data);
2063 fclose(logfp);
2064 strbuf_release(&sb);
2065 return ret;
2066}
7bd9bcf3 2067
2880d16f
MH
2068struct files_reflog_iterator {
2069 struct ref_iterator base;
7bd9bcf3 2070
2f40e954 2071 struct ref_store *ref_store;
2880d16f
MH
2072 struct dir_iterator *dir_iterator;
2073 struct object_id oid;
2074};
7bd9bcf3 2075
2880d16f
MH
2076static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
2077{
2078 struct files_reflog_iterator *iter =
2079 (struct files_reflog_iterator *)ref_iterator;
2080 struct dir_iterator *diter = iter->dir_iterator;
2081 int ok;
2082
2083 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
2084 int flags;
2085
2086 if (!S_ISREG(diter->st.st_mode))
7bd9bcf3 2087 continue;
2880d16f
MH
2088 if (diter->basename[0] == '.')
2089 continue;
2090 if (ends_with(diter->basename, ".lock"))
7bd9bcf3 2091 continue;
7bd9bcf3 2092
2f40e954
NTND
2093 if (refs_read_ref_full(iter->ref_store,
2094 diter->relative_path, 0,
34c290a6 2095 &iter->oid, &flags)) {
2880d16f
MH
2096 error("bad ref for %s", diter->path.buf);
2097 continue;
7bd9bcf3 2098 }
2880d16f
MH
2099
2100 iter->base.refname = diter->relative_path;
2101 iter->base.oid = &iter->oid;
2102 iter->base.flags = flags;
2103 return ITER_OK;
7bd9bcf3 2104 }
2880d16f
MH
2105
2106 iter->dir_iterator = NULL;
2107 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
2108 ok = ITER_ERROR;
2109 return ok;
2110}
2111
2112static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
2113 struct object_id *peeled)
2114{
033abf97 2115 BUG("ref_iterator_peel() called for reflog_iterator");
2880d16f
MH
2116}
2117
2118static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
2119{
2120 struct files_reflog_iterator *iter =
2121 (struct files_reflog_iterator *)ref_iterator;
2122 int ok = ITER_DONE;
2123
2124 if (iter->dir_iterator)
2125 ok = dir_iterator_abort(iter->dir_iterator);
2126
2127 base_ref_iterator_free(ref_iterator);
2128 return ok;
2129}
2130
2131static struct ref_iterator_vtable files_reflog_iterator_vtable = {
2132 files_reflog_iterator_advance,
2133 files_reflog_iterator_peel,
2134 files_reflog_iterator_abort
2135};
2136
944b4e30
NTND
2137static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
2138 const char *gitdir)
2880d16f
MH
2139{
2140 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
2141 struct ref_iterator *ref_iterator = &iter->base;
e9dcc305 2142 struct strbuf sb = STRBUF_INIT;
2880d16f 2143
8738a8a4 2144 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0);
944b4e30 2145 strbuf_addf(&sb, "%s/logs", gitdir);
e9dcc305 2146 iter->dir_iterator = dir_iterator_begin(sb.buf);
2f40e954 2147 iter->ref_store = ref_store;
e9dcc305 2148 strbuf_release(&sb);
944b4e30 2149
2880d16f 2150 return ref_iterator;
7bd9bcf3
MH
2151}
2152
944b4e30
NTND
2153static enum iterator_selection reflog_iterator_select(
2154 struct ref_iterator *iter_worktree,
2155 struct ref_iterator *iter_common,
2156 void *cb_data)
2157{
2158 if (iter_worktree) {
2159 /*
2160 * We're a bit loose here. We probably should ignore
2161 * common refs if they are accidentally added as
2162 * per-worktree refs.
2163 */
2164 return ITER_SELECT_0;
2165 } else if (iter_common) {
2166 if (ref_type(iter_common->refname) == REF_TYPE_NORMAL)
2167 return ITER_SELECT_1;
2168
2169 /*
2170 * The main ref store may contain main worktree's
2171 * per-worktree refs, which should be ignored
2172 */
2173 return ITER_SKIP_1;
2174 } else
2175 return ITER_DONE;
2176}
2177
2178static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2179{
2180 struct files_ref_store *refs =
2181 files_downcast(ref_store, REF_STORE_READ,
2182 "reflog_iterator_begin");
2183
2184 if (!strcmp(refs->gitdir, refs->gitcommondir)) {
2185 return reflog_iterator_begin(ref_store, refs->gitcommondir);
2186 } else {
2187 return merge_ref_iterator_begin(
1a2e1a76 2188 0,
944b4e30
NTND
2189 reflog_iterator_begin(ref_store, refs->gitdir),
2190 reflog_iterator_begin(ref_store, refs->gitcommondir),
2191 reflog_iterator_select, refs);
2192 }
2193}
2194
165056b2 2195/*
92b1551b
MH
2196 * If update is a direct update of head_ref (the reference pointed to
2197 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
2198 */
2199static int split_head_update(struct ref_update *update,
2200 struct ref_transaction *transaction,
2201 const char *head_ref,
2202 struct string_list *affected_refnames,
2203 struct strbuf *err)
2204{
2205 struct string_list_item *item;
2206 struct ref_update *new_update;
2207
2208 if ((update->flags & REF_LOG_ONLY) ||
acedcde7 2209 (update->flags & REF_IS_PRUNING) ||
92b1551b
MH
2210 (update->flags & REF_UPDATE_VIA_HEAD))
2211 return 0;
2212
2213 if (strcmp(update->refname, head_ref))
2214 return 0;
2215
2216 /*
2217 * First make sure that HEAD is not already in the
276d0e35 2218 * transaction. This check is O(lg N) in the transaction
92b1551b
MH
2219 * size, but it happens at most once per transaction.
2220 */
276d0e35 2221 if (string_list_has_string(affected_refnames, "HEAD")) {
92b1551b
MH
2222 /* An entry already existed */
2223 strbuf_addf(err,
2224 "multiple updates for 'HEAD' (including one "
2225 "via its referent '%s') are not allowed",
2226 update->refname);
2227 return TRANSACTION_NAME_CONFLICT;
2228 }
2229
2230 new_update = ref_transaction_add_update(
2231 transaction, "HEAD",
91774afc 2232 update->flags | REF_LOG_ONLY | REF_NO_DEREF,
89f3bbdd 2233 &update->new_oid, &update->old_oid,
92b1551b
MH
2234 update->msg);
2235
276d0e35
2236 /*
2237 * Add "HEAD". This insertion is O(N) in the transaction
2238 * size, but it happens at most once per transaction.
2239 * Add new_update->refname instead of a literal "HEAD".
2240 */
2241 if (strcmp(new_update->refname, "HEAD"))
2242 BUG("%s unexpectedly not 'HEAD'", new_update->refname);
2243 item = string_list_insert(affected_refnames, new_update->refname);
92b1551b
MH
2244 item->util = new_update;
2245
2246 return 0;
2247}
2248
2249/*
2250 * update is for a symref that points at referent and doesn't have
91774afc
MH
2251 * REF_NO_DEREF set. Split it into two updates:
2252 * - The original update, but with REF_LOG_ONLY and REF_NO_DEREF set
92b1551b
MH
2253 * - A new, separate update for the referent reference
2254 * Note that the new update will itself be subject to splitting when
2255 * the iteration gets to it.
2256 */
fcc42ea0
MH
2257static int split_symref_update(struct files_ref_store *refs,
2258 struct ref_update *update,
92b1551b
MH
2259 const char *referent,
2260 struct ref_transaction *transaction,
2261 struct string_list *affected_refnames,
2262 struct strbuf *err)
2263{
2264 struct string_list_item *item;
2265 struct ref_update *new_update;
2266 unsigned int new_flags;
2267
2268 /*
2269 * First make sure that referent is not already in the
c299468b 2270 * transaction. This check is O(lg N) in the transaction
92b1551b
MH
2271 * size, but it happens at most once per symref in a
2272 * transaction.
2273 */
c299468b
2274 if (string_list_has_string(affected_refnames, referent)) {
2275 /* An entry already exists */
92b1551b
MH
2276 strbuf_addf(err,
2277 "multiple updates for '%s' (including one "
2278 "via symref '%s') are not allowed",
2279 referent, update->refname);
2280 return TRANSACTION_NAME_CONFLICT;
2281 }
2282
2283 new_flags = update->flags;
2284 if (!strcmp(update->refname, "HEAD")) {
2285 /*
2286 * Record that the new update came via HEAD, so that
2287 * when we process it, split_head_update() doesn't try
2288 * to add another reflog update for HEAD. Note that
2289 * this bit will be propagated if the new_update
2290 * itself needs to be split.
2291 */
2292 new_flags |= REF_UPDATE_VIA_HEAD;
2293 }
2294
2295 new_update = ref_transaction_add_update(
2296 transaction, referent, new_flags,
89f3bbdd 2297 &update->new_oid, &update->old_oid,
92b1551b
MH
2298 update->msg);
2299
6e30b2f6
MH
2300 new_update->parent_update = update;
2301
2302 /*
2303 * Change the symbolic ref update to log only. Also, it
78fb4579 2304 * doesn't need to check its old OID value, as that will be
6e30b2f6
MH
2305 * done when new_update is processed.
2306 */
91774afc 2307 update->flags |= REF_LOG_ONLY | REF_NO_DEREF;
6e30b2f6 2308 update->flags &= ~REF_HAVE_OLD;
92b1551b 2309
c299468b
2310 /*
2311 * Add the referent. This insertion is O(N) in the transaction
2312 * size, but it happens at most once per symref in a
2313 * transaction. Make sure to add new_update->refname, which will
2314 * be valid as long as affected_refnames is in use, and NOT
2315 * referent, which might soon be freed by our caller.
2316 */
2317 item = string_list_insert(affected_refnames, new_update->refname);
2318 if (item->util)
2319 BUG("%s unexpectedly found in affected_refnames",
2320 new_update->refname);
92b1551b
MH
2321 item->util = new_update;
2322
2323 return 0;
2324}
2325
6e30b2f6
MH
2326/*
2327 * Return the refname under which update was originally requested.
2328 */
2329static const char *original_update_refname(struct ref_update *update)
2330{
2331 while (update->parent_update)
2332 update = update->parent_update;
2333
2334 return update->refname;
2335}
2336
e3f51039
MH
2337/*
2338 * Check whether the REF_HAVE_OLD and old_oid values stored in update
2339 * are consistent with oid, which is the reference's current value. If
2340 * everything is OK, return 0; otherwise, write an error message to
2341 * err and return -1.
2342 */
2343static int check_old_oid(struct ref_update *update, struct object_id *oid,
2344 struct strbuf *err)
2345{
2346 if (!(update->flags & REF_HAVE_OLD) ||
4a7e27e9 2347 oideq(oid, &update->old_oid))
e3f51039
MH
2348 return 0;
2349
98491298 2350 if (is_null_oid(&update->old_oid))
e3f51039
MH
2351 strbuf_addf(err, "cannot lock ref '%s': "
2352 "reference already exists",
2353 original_update_refname(update));
2354 else if (is_null_oid(oid))
2355 strbuf_addf(err, "cannot lock ref '%s': "
2356 "reference is missing but expected %s",
2357 original_update_refname(update),
98491298 2358 oid_to_hex(&update->old_oid));
e3f51039
MH
2359 else
2360 strbuf_addf(err, "cannot lock ref '%s': "
2361 "is at %s but expected %s",
2362 original_update_refname(update),
2363 oid_to_hex(oid),
98491298 2364 oid_to_hex(&update->old_oid));
e3f51039
MH
2365
2366 return -1;
2367}
2368
92b1551b
MH
2369/*
2370 * Prepare for carrying out update:
2371 * - Lock the reference referred to by update.
2372 * - Read the reference under lock.
78fb4579 2373 * - Check that its old OID value (if specified) is correct, and in
92b1551b
MH
2374 * any case record it in update->lock->old_oid for later use when
2375 * writing the reflog.
91774afc 2376 * - If it is a symref update without REF_NO_DEREF, split it up into a
92b1551b
MH
2377 * REF_LOG_ONLY update of the symref and add a separate update for
2378 * the referent to transaction.
2379 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
2380 * update of HEAD.
165056b2 2381 */
b3bbbc5c
MH
2382static int lock_ref_for_update(struct files_ref_store *refs,
2383 struct ref_update *update,
165056b2 2384 struct ref_transaction *transaction,
92b1551b 2385 const char *head_ref,
165056b2
MH
2386 struct string_list *affected_refnames,
2387 struct strbuf *err)
2388{
92b1551b
MH
2389 struct strbuf referent = STRBUF_INIT;
2390 int mustexist = (update->flags & REF_HAVE_OLD) &&
98491298 2391 !is_null_oid(&update->old_oid);
851e1fbd 2392 int ret = 0;
92b1551b 2393 struct ref_lock *lock;
165056b2 2394
32c597e7 2395 files_assert_main_repository(refs, "lock_ref_for_update");
b3bbbc5c 2396
98491298 2397 if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid))
165056b2 2398 update->flags |= REF_DELETING;
92b1551b
MH
2399
2400 if (head_ref) {
2401 ret = split_head_update(update, transaction, head_ref,
2402 affected_refnames, err);
2403 if (ret)
851e1fbd 2404 goto out;
92b1551b
MH
2405 }
2406
f7b0a987 2407 ret = lock_raw_ref(refs, update->refname, mustexist,
92b1551b 2408 affected_refnames, NULL,
7d618264 2409 &lock, &referent,
92b1551b 2410 &update->type, err);
92b1551b 2411 if (ret) {
165056b2
MH
2412 char *reason;
2413
165056b2
MH
2414 reason = strbuf_detach(err, NULL);
2415 strbuf_addf(err, "cannot lock ref '%s': %s",
e3f51039 2416 original_update_refname(update), reason);
165056b2 2417 free(reason);
851e1fbd 2418 goto out;
165056b2 2419 }
92b1551b 2420
7d618264 2421 update->backend_data = lock;
92b1551b 2422
8169d0d0 2423 if (update->type & REF_ISSYMREF) {
91774afc 2424 if (update->flags & REF_NO_DEREF) {
6e30b2f6
MH
2425 /*
2426 * We won't be reading the referent as part of
2427 * the transaction, so we have to read it here
78fb4579 2428 * to record and possibly check old_oid:
6e30b2f6 2429 */
2f40e954
NTND
2430 if (refs_read_ref_full(&refs->base,
2431 referent.buf, 0,
34c290a6 2432 &lock->old_oid, NULL)) {
6e30b2f6
MH
2433 if (update->flags & REF_HAVE_OLD) {
2434 strbuf_addf(err, "cannot lock ref '%s': "
e3f51039
MH
2435 "error reading reference",
2436 original_update_refname(update));
3f5ef95b 2437 ret = TRANSACTION_GENERIC_ERROR;
851e1fbd 2438 goto out;
6e30b2f6 2439 }
e3f51039 2440 } else if (check_old_oid(update, &lock->old_oid, err)) {
851e1fbd
2441 ret = TRANSACTION_GENERIC_ERROR;
2442 goto out;
8169d0d0 2443 }
6e30b2f6
MH
2444 } else {
2445 /*
2446 * Create a new update for the reference this
2447 * symref is pointing at. Also, we will record
78fb4579 2448 * and verify old_oid for this update as part
6e30b2f6
MH
2449 * of processing the split-off update, so we
2450 * don't have to do it here.
2451 */
fcc42ea0
MH
2452 ret = split_symref_update(refs, update,
2453 referent.buf, transaction,
92b1551b
MH
2454 affected_refnames, err);
2455 if (ret)
851e1fbd 2456 goto out;
92b1551b 2457 }
6e30b2f6
MH
2458 } else {
2459 struct ref_update *parent_update;
8169d0d0 2460
851e1fbd
2461 if (check_old_oid(update, &lock->old_oid, err)) {
2462 ret = TRANSACTION_GENERIC_ERROR;
2463 goto out;
2464 }
e3f51039 2465
6e30b2f6
MH
2466 /*
2467 * If this update is happening indirectly because of a
78fb4579 2468 * symref update, record the old OID in the parent
6e30b2f6
MH
2469 * update:
2470 */
2471 for (parent_update = update->parent_update;
2472 parent_update;
2473 parent_update = parent_update->parent_update) {
7d618264
DT
2474 struct ref_lock *parent_lock = parent_update->backend_data;
2475 oidcpy(&parent_lock->old_oid, &lock->old_oid);
6e30b2f6 2476 }
92b1551b
MH
2477 }
2478
165056b2
MH
2479 if ((update->flags & REF_HAVE_NEW) &&
2480 !(update->flags & REF_DELETING) &&
2481 !(update->flags & REF_LOG_ONLY)) {
92b1551b 2482 if (!(update->type & REF_ISSYMREF) &&
4a7e27e9 2483 oideq(&lock->old_oid, &update->new_oid)) {
165056b2
MH
2484 /*
2485 * The reference already has the desired
2486 * value, so we don't need to write it.
2487 */
4417df8c 2488 } else if (write_ref_to_lockfile(lock, &update->new_oid,
165056b2
MH
2489 err)) {
2490 char *write_err = strbuf_detach(err, NULL);
2491
2492 /*
2493 * The lock was freed upon failure of
2494 * write_ref_to_lockfile():
2495 */
7d618264 2496 update->backend_data = NULL;
165056b2 2497 strbuf_addf(err,
e3f51039 2498 "cannot update ref '%s': %s",
165056b2
MH
2499 update->refname, write_err);
2500 free(write_err);
851e1fbd
2501 ret = TRANSACTION_GENERIC_ERROR;
2502 goto out;
165056b2
MH
2503 } else {
2504 update->flags |= REF_NEEDS_COMMIT;
2505 }
2506 }
2507 if (!(update->flags & REF_NEEDS_COMMIT)) {
2508 /*
2509 * We didn't call write_ref_to_lockfile(), so
2510 * the lockfile is still open. Close it to
2511 * free up the file descriptor:
2512 */
83a3069a 2513 if (close_ref_gently(lock)) {
165056b2
MH
2514 strbuf_addf(err, "couldn't close '%s.lock'",
2515 update->refname);
851e1fbd
2516 ret = TRANSACTION_GENERIC_ERROR;
2517 goto out;
165056b2
MH
2518 }
2519 }
851e1fbd
2520
2521out:
2522 strbuf_release(&referent);
2523 return ret;
165056b2
MH
2524}
2525
dc39e099
MH
2526struct files_transaction_backend_data {
2527 struct ref_transaction *packed_transaction;
2528 int packed_refs_locked;
2529};
2530
c0ca9357
MH
2531/*
2532 * Unlock any references in `transaction` that are still locked, and
2533 * mark the transaction closed.
2534 */
dc39e099
MH
2535static void files_transaction_cleanup(struct files_ref_store *refs,
2536 struct ref_transaction *transaction)
c0ca9357
MH
2537{
2538 size_t i;
dc39e099
MH
2539 struct files_transaction_backend_data *backend_data =
2540 transaction->backend_data;
2541 struct strbuf err = STRBUF_INIT;
c0ca9357
MH
2542
2543 for (i = 0; i < transaction->nr; i++) {
2544 struct ref_update *update = transaction->updates[i];
2545 struct ref_lock *lock = update->backend_data;
2546
2547 if (lock) {
2548 unlock_ref(lock);
2549 update->backend_data = NULL;
2550 }
2551 }
2552
dc39e099
MH
2553 if (backend_data->packed_transaction &&
2554 ref_transaction_abort(backend_data->packed_transaction, &err)) {
2555 error("error aborting transaction: %s", err.buf);
2556 strbuf_release(&err);
2557 }
2558
2559 if (backend_data->packed_refs_locked)
2560 packed_refs_unlock(refs->packed_ref_store);
2561
2562 free(backend_data);
2563
c0ca9357
MH
2564 transaction->state = REF_TRANSACTION_CLOSED;
2565}
2566
30173b88
MH
2567static int files_transaction_prepare(struct ref_store *ref_store,
2568 struct ref_transaction *transaction,
2569 struct strbuf *err)
7bd9bcf3 2570{
00eebe35 2571 struct files_ref_store *refs =
9e7ec634 2572 files_downcast(ref_store, REF_STORE_WRITE,
30173b88 2573 "ref_transaction_prepare");
43a2dfde
MH
2574 size_t i;
2575 int ret = 0;
7bd9bcf3 2576 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
92b1551b
MH
2577 char *head_ref = NULL;
2578 int head_type;
dc39e099
MH
2579 struct files_transaction_backend_data *backend_data;
2580 struct ref_transaction *packed_transaction = NULL;
7bd9bcf3
MH
2581
2582 assert(err);
2583
c0ca9357
MH
2584 if (!transaction->nr)
2585 goto cleanup;
7bd9bcf3 2586
dc39e099
MH
2587 backend_data = xcalloc(1, sizeof(*backend_data));
2588 transaction->backend_data = backend_data;
2589
92b1551b
MH
2590 /*
2591 * Fail if a refname appears more than once in the
2592 * transaction. (If we end up splitting up any updates using
2593 * split_symref_update() or split_head_update(), those
2594 * functions will check that the new updates don't have the
62c72d1f 2595 * same refname as any existing ones.) Also fail if any of the
acedcde7 2596 * updates use REF_IS_PRUNING without REF_NO_DEREF.
92b1551b
MH
2597 */
2598 for (i = 0; i < transaction->nr; i++) {
2599 struct ref_update *update = transaction->updates[i];
2600 struct string_list_item *item =
2601 string_list_append(&affected_refnames, update->refname);
2602
acedcde7 2603 if ((update->flags & REF_IS_PRUNING) &&
91774afc 2604 !(update->flags & REF_NO_DEREF))
acedcde7 2605 BUG("REF_IS_PRUNING set without REF_NO_DEREF");
62c72d1f 2606
92b1551b
MH
2607 /*
2608 * We store a pointer to update in item->util, but at
2609 * the moment we never use the value of this field
2610 * except to check whether it is non-NULL.
2611 */
2612 item->util = update;
2613 }
7bd9bcf3
MH
2614 string_list_sort(&affected_refnames);
2615 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2616 ret = TRANSACTION_GENERIC_ERROR;
2617 goto cleanup;
2618 }
2619
92b1551b
MH
2620 /*
2621 * Special hack: If a branch is updated directly and HEAD
2622 * points to it (may happen on the remote side of a push
2623 * for example) then logically the HEAD reflog should be
2624 * updated too.
2625 *
2626 * A generic solution would require reverse symref lookups,
2627 * but finding all symrefs pointing to a given branch would be
2628 * rather costly for this rare event (the direct update of a
2629 * branch) to be worth it. So let's cheat and check with HEAD
2630 * only, which should cover 99% of all usage scenarios (even
2631 * 100% of the default ones).
2632 *
2633 * So if HEAD is a symbolic reference, then record the name of
2634 * the reference that it points to. If we see an update of
2635 * head_ref within the transaction, then split_head_update()
2636 * arranges for the reflog of HEAD to be updated, too.
2637 */
2f40e954
NTND
2638 head_ref = refs_resolve_refdup(ref_store, "HEAD",
2639 RESOLVE_REF_NO_RECURSE,
872ccb2c 2640 NULL, &head_type);
92b1551b
MH
2641
2642 if (head_ref && !(head_type & REF_ISSYMREF)) {
6a83d902 2643 FREE_AND_NULL(head_ref);
92b1551b
MH
2644 }
2645
7bd9bcf3
MH
2646 /*
2647 * Acquire all locks, verify old values if provided, check
2648 * that new values are valid, and write new values to the
2649 * lockfiles, ready to be activated. Only keep one lockfile
2650 * open at a time to avoid running out of file descriptors.
30173b88
MH
2651 * Note that lock_ref_for_update() might append more updates
2652 * to the transaction.
7bd9bcf3 2653 */
efe47281
MH
2654 for (i = 0; i < transaction->nr; i++) {
2655 struct ref_update *update = transaction->updates[i];
7bd9bcf3 2656
b3bbbc5c
MH
2657 ret = lock_ref_for_update(refs, update, transaction,
2658 head_ref, &affected_refnames, err);
165056b2 2659 if (ret)
da5267f1 2660 goto cleanup;
dc39e099
MH
2661
2662 if (update->flags & REF_DELETING &&
2663 !(update->flags & REF_LOG_ONLY) &&
acedcde7 2664 !(update->flags & REF_IS_PRUNING)) {
dc39e099
MH
2665 /*
2666 * This reference has to be deleted from
2667 * packed-refs if it exists there.
2668 */
2669 if (!packed_transaction) {
2670 packed_transaction = ref_store_transaction_begin(
2671 refs->packed_ref_store, err);
2672 if (!packed_transaction) {
2673 ret = TRANSACTION_GENERIC_ERROR;
2674 goto cleanup;
2675 }
2676
2677 backend_data->packed_transaction =
2678 packed_transaction;
2679 }
2680
2681 ref_transaction_add_update(
2682 packed_transaction, update->refname,
91774afc 2683 REF_HAVE_NEW | REF_NO_DEREF,
b0ca4110 2684 &update->new_oid, NULL,
dc39e099
MH
2685 NULL);
2686 }
2687 }
2688
2689 if (packed_transaction) {
2690 if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
2691 ret = TRANSACTION_GENERIC_ERROR;
2692 goto cleanup;
2693 }
2694 backend_data->packed_refs_locked = 1;
7c6bd25c
MH
2695
2696 if (is_packed_transaction_needed(refs->packed_ref_store,
2697 packed_transaction)) {
2698 ret = ref_transaction_prepare(packed_transaction, err);
249e8dc7
JK
2699 /*
2700 * A failure during the prepare step will abort
2701 * itself, but not free. Do that now, and disconnect
2702 * from the files_transaction so it does not try to
2703 * abort us when we hit the cleanup code below.
2704 */
2705 if (ret) {
2706 ref_transaction_free(packed_transaction);
2707 backend_data->packed_transaction = NULL;
2708 }
7c6bd25c
MH
2709 } else {
2710 /*
2711 * We can skip rewriting the `packed-refs`
2712 * file. But we do need to leave it locked, so
2713 * that somebody else doesn't pack a reference
2714 * that we are trying to delete.
2715 */
2716 if (ref_transaction_abort(packed_transaction, err)) {
2717 ret = TRANSACTION_GENERIC_ERROR;
2718 goto cleanup;
2719 }
2720 backend_data->packed_transaction = NULL;
2721 }
30173b88
MH
2722 }
2723
2724cleanup:
2725 free(head_ref);
2726 string_list_clear(&affected_refnames, 0);
2727
2728 if (ret)
dc39e099 2729 files_transaction_cleanup(refs, transaction);
30173b88
MH
2730 else
2731 transaction->state = REF_TRANSACTION_PREPARED;
2732
2733 return ret;
2734}
2735
2736static int files_transaction_finish(struct ref_store *ref_store,
2737 struct ref_transaction *transaction,
2738 struct strbuf *err)
2739{
2740 struct files_ref_store *refs =
2741 files_downcast(ref_store, 0, "ref_transaction_finish");
2742 size_t i;
2743 int ret = 0;
30173b88 2744 struct strbuf sb = STRBUF_INIT;
dc39e099
MH
2745 struct files_transaction_backend_data *backend_data;
2746 struct ref_transaction *packed_transaction;
2747
30173b88
MH
2748
2749 assert(err);
2750
2751 if (!transaction->nr) {
2752 transaction->state = REF_TRANSACTION_CLOSED;
2753 return 0;
7bd9bcf3 2754 }
7bd9bcf3 2755
dc39e099
MH
2756 backend_data = transaction->backend_data;
2757 packed_transaction = backend_data->packed_transaction;
2758
7bd9bcf3 2759 /* Perform updates first so live commits remain referenced */
efe47281
MH
2760 for (i = 0; i < transaction->nr; i++) {
2761 struct ref_update *update = transaction->updates[i];
7d618264 2762 struct ref_lock *lock = update->backend_data;
7bd9bcf3 2763
d99aa884
DT
2764 if (update->flags & REF_NEEDS_COMMIT ||
2765 update->flags & REF_LOG_ONLY) {
802de3da
NTND
2766 if (files_log_ref_write(refs,
2767 lock->ref_name,
4417df8c 2768 &lock->old_oid,
2769 &update->new_oid,
81b1b6d4
MH
2770 update->msg, update->flags,
2771 err)) {
92b1551b
MH
2772 char *old_msg = strbuf_detach(err, NULL);
2773
2774 strbuf_addf(err, "cannot update the ref '%s': %s",
2775 lock->ref_name, old_msg);
2776 free(old_msg);
2777 unlock_ref(lock);
7d618264 2778 update->backend_data = NULL;
7bd9bcf3
MH
2779 ret = TRANSACTION_GENERIC_ERROR;
2780 goto cleanup;
7bd9bcf3
MH
2781 }
2782 }
7bd9bcf3 2783 if (update->flags & REF_NEEDS_COMMIT) {
00eebe35 2784 clear_loose_ref_cache(refs);
92b1551b
MH
2785 if (commit_ref(lock)) {
2786 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
2787 unlock_ref(lock);
7d618264 2788 update->backend_data = NULL;
7bd9bcf3
MH
2789 ret = TRANSACTION_GENERIC_ERROR;
2790 goto cleanup;
7bd9bcf3
MH
2791 }
2792 }
2793 }
dc39e099 2794
5e00a6c8
MH
2795 /*
2796 * Now that updates are safely completed, we can perform
2797 * deletes. First delete the reflogs of any references that
2798 * will be deleted, since (in the unexpected event of an
2799 * error) leaving a reference without a reflog is less bad
2800 * than leaving a reflog without a reference (the latter is a
2801 * mildly invalid repository state):
2802 */
2803 for (i = 0; i < transaction->nr; i++) {
2804 struct ref_update *update = transaction->updates[i];
2805 if (update->flags & REF_DELETING &&
2806 !(update->flags & REF_LOG_ONLY) &&
acedcde7 2807 !(update->flags & REF_IS_PRUNING)) {
5e00a6c8
MH
2808 strbuf_reset(&sb);
2809 files_reflog_path(refs, &sb, update->refname);
2810 if (!unlink_or_warn(sb.buf))
2811 try_remove_empty_parents(refs, update->refname,
2812 REMOVE_EMPTY_PARENTS_REFLOG);
2813 }
2814 }
2815
dc39e099
MH
2816 /*
2817 * Perform deletes now that updates are safely completed.
2818 *
2819 * First delete any packed versions of the references, while
2820 * retaining the packed-refs lock:
2821 */
2822 if (packed_transaction) {
2823 ret = ref_transaction_commit(packed_transaction, err);
2824 ref_transaction_free(packed_transaction);
2825 packed_transaction = NULL;
2826 backend_data->packed_transaction = NULL;
2827 if (ret)
2828 goto cleanup;
2829 }
2830
2831 /* Now delete the loose versions of the references: */
efe47281
MH
2832 for (i = 0; i < transaction->nr; i++) {
2833 struct ref_update *update = transaction->updates[i];
7d618264 2834 struct ref_lock *lock = update->backend_data;
7bd9bcf3 2835
d99aa884
DT
2836 if (update->flags & REF_DELETING &&
2837 !(update->flags & REF_LOG_ONLY)) {
ce0af24d
MH
2838 if (!(update->type & REF_ISPACKED) ||
2839 update->type & REF_ISSYMREF) {
2840 /* It is a loose reference. */
e9dcc305 2841 strbuf_reset(&sb);
19e02f4f 2842 files_ref_path(refs, &sb, lock->ref_name);
e9dcc305 2843 if (unlink_or_msg(sb.buf, err)) {
ce0af24d
MH
2844 ret = TRANSACTION_GENERIC_ERROR;
2845 goto cleanup;
2846 }
44639777 2847 update->flags |= REF_DELETED_LOOSE;
7bd9bcf3 2848 }
7bd9bcf3
MH
2849 }
2850 }
2851
00eebe35 2852 clear_loose_ref_cache(refs);
7bd9bcf3
MH
2853
2854cleanup:
dc39e099 2855 files_transaction_cleanup(refs, transaction);
7bd9bcf3 2856
44639777
MH
2857 for (i = 0; i < transaction->nr; i++) {
2858 struct ref_update *update = transaction->updates[i];
44639777
MH
2859
2860 if (update->flags & REF_DELETED_LOOSE) {
2861 /*
2862 * The loose reference was deleted. Delete any
2863 * empty parent directories. (Note that this
2864 * can only work because we have already
2865 * removed the lockfile.)
2866 */
802de3da 2867 try_remove_empty_parents(refs, update->refname,
44639777
MH
2868 REMOVE_EMPTY_PARENTS_REF);
2869 }
2870 }
2871
30173b88 2872 strbuf_release(&sb);
7bd9bcf3
MH
2873 return ret;
2874}
2875
30173b88
MH
2876static int files_transaction_abort(struct ref_store *ref_store,
2877 struct ref_transaction *transaction,
2878 struct strbuf *err)
2879{
dc39e099
MH
2880 struct files_ref_store *refs =
2881 files_downcast(ref_store, 0, "ref_transaction_abort");
2882
2883 files_transaction_cleanup(refs, transaction);
30173b88
MH
2884 return 0;
2885}
2886
7bd9bcf3
MH
2887static int ref_present(const char *refname,
2888 const struct object_id *oid, int flags, void *cb_data)
2889{
2890 struct string_list *affected_refnames = cb_data;
2891
2892 return string_list_has_string(affected_refnames, refname);
2893}
2894
fc681463
DT
2895static int files_initial_transaction_commit(struct ref_store *ref_store,
2896 struct ref_transaction *transaction,
2897 struct strbuf *err)
7bd9bcf3 2898{
d99825ab 2899 struct files_ref_store *refs =
9e7ec634
NTND
2900 files_downcast(ref_store, REF_STORE_WRITE,
2901 "initial_ref_transaction_commit");
43a2dfde
MH
2902 size_t i;
2903 int ret = 0;
7bd9bcf3 2904 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
1444bfe0 2905 struct ref_transaction *packed_transaction = NULL;
7bd9bcf3
MH
2906
2907 assert(err);
2908
2909 if (transaction->state != REF_TRANSACTION_OPEN)
033abf97 2910 BUG("commit called for transaction that is not open");
7bd9bcf3
MH
2911
2912 /* Fail if a refname appears more than once in the transaction: */
efe47281
MH
2913 for (i = 0; i < transaction->nr; i++)
2914 string_list_append(&affected_refnames,
2915 transaction->updates[i]->refname);
7bd9bcf3
MH
2916 string_list_sort(&affected_refnames);
2917 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2918 ret = TRANSACTION_GENERIC_ERROR;
2919 goto cleanup;
2920 }
2921
2922 /*
2923 * It's really undefined to call this function in an active
2924 * repository or when there are existing references: we are
2925 * only locking and changing packed-refs, so (1) any
2926 * simultaneous processes might try to change a reference at
2927 * the same time we do, and (2) any existing loose versions of
2928 * the references that we are setting would have precedence
2929 * over our values. But some remote helpers create the remote
2930 * "HEAD" and "master" branches before calling this function,
2931 * so here we really only check that none of the references
2932 * that we are creating already exists.
2933 */
2f40e954
NTND
2934 if (refs_for_each_rawref(&refs->base, ref_present,
2935 &affected_refnames))
033abf97 2936 BUG("initial ref transaction called with existing refs");
7bd9bcf3 2937
1444bfe0
MH
2938 packed_transaction = ref_store_transaction_begin(refs->packed_ref_store, err);
2939 if (!packed_transaction) {
2940 ret = TRANSACTION_GENERIC_ERROR;
2941 goto cleanup;
2942 }
2943
efe47281
MH
2944 for (i = 0; i < transaction->nr; i++) {
2945 struct ref_update *update = transaction->updates[i];
7bd9bcf3
MH
2946
2947 if ((update->flags & REF_HAVE_OLD) &&
98491298 2948 !is_null_oid(&update->old_oid))
033abf97 2949 BUG("initial ref transaction with old_sha1 set");
7d2df051
NTND
2950 if (refs_verify_refname_available(&refs->base, update->refname,
2951 &affected_refnames, NULL,
2952 err)) {
7bd9bcf3
MH
2953 ret = TRANSACTION_NAME_CONFLICT;
2954 goto cleanup;
2955 }
1444bfe0
MH
2956
2957 /*
2958 * Add a reference creation for this reference to the
2959 * packed-refs transaction:
2960 */
2961 ref_transaction_add_update(packed_transaction, update->refname,
2962 update->flags & ~REF_HAVE_OLD,
89f3bbdd 2963 &update->new_oid, &update->old_oid,
1444bfe0 2964 NULL);
7bd9bcf3
MH
2965 }
2966
c8bed835 2967 if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
7bd9bcf3
MH
2968 ret = TRANSACTION_GENERIC_ERROR;
2969 goto cleanup;
2970 }
2971
1444bfe0 2972 if (initial_ref_transaction_commit(packed_transaction, err)) {
7bd9bcf3 2973 ret = TRANSACTION_GENERIC_ERROR;
7bd9bcf3
MH
2974 }
2975
81fcb698 2976 packed_refs_unlock(refs->packed_ref_store);
7bd9bcf3 2977cleanup:
1444bfe0
MH
2978 if (packed_transaction)
2979 ref_transaction_free(packed_transaction);
7bd9bcf3
MH
2980 transaction->state = REF_TRANSACTION_CLOSED;
2981 string_list_clear(&affected_refnames, 0);
2982 return ret;
2983}
2984
2985struct expire_reflog_cb {
2986 unsigned int flags;
2987 reflog_expiry_should_prune_fn *should_prune_fn;
2988 void *policy_cb;
2989 FILE *newlog;
9461d272 2990 struct object_id last_kept_oid;
7bd9bcf3
MH
2991};
2992
9461d272 2993static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
dddbad72 2994 const char *email, timestamp_t timestamp, int tz,
7bd9bcf3
MH
2995 const char *message, void *cb_data)
2996{
2997 struct expire_reflog_cb *cb = cb_data;
2998 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
2999
3000 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
9461d272 3001 ooid = &cb->last_kept_oid;
7bd9bcf3 3002
4322478a 3003 if ((*cb->should_prune_fn)(ooid, noid, email, timestamp, tz,
7bd9bcf3
MH
3004 message, policy_cb)) {
3005 if (!cb->newlog)
3006 printf("would prune %s", message);
3007 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3008 printf("prune %s", message);
3009 } else {
3010 if (cb->newlog) {
cb71f8bd 3011 fprintf(cb->newlog, "%s %s %s %"PRItime" %+05d\t%s",
9461d272 3012 oid_to_hex(ooid), oid_to_hex(noid),
7bd9bcf3 3013 email, timestamp, tz, message);
9461d272 3014 oidcpy(&cb->last_kept_oid, noid);
7bd9bcf3
MH
3015 }
3016 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3017 printf("keep %s", message);
3018 }
3019 return 0;
3020}
3021
e3688bd6 3022static int files_reflog_expire(struct ref_store *ref_store,
0155f710 3023 const char *refname, const struct object_id *oid,
e3688bd6
DT
3024 unsigned int flags,
3025 reflog_expiry_prepare_fn prepare_fn,
3026 reflog_expiry_should_prune_fn should_prune_fn,
3027 reflog_expiry_cleanup_fn cleanup_fn,
3028 void *policy_cb_data)
7bd9bcf3 3029{
7eb27cdf 3030 struct files_ref_store *refs =
9e7ec634 3031 files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
b2275868 3032 struct lock_file reflog_lock = LOCK_INIT;
7bd9bcf3
MH
3033 struct expire_reflog_cb cb;
3034 struct ref_lock *lock;
802de3da 3035 struct strbuf log_file_sb = STRBUF_INIT;
7bd9bcf3
MH
3036 char *log_file;
3037 int status = 0;
3038 int type;
3039 struct strbuf err = STRBUF_INIT;
3040
3041 memset(&cb, 0, sizeof(cb));
3042 cb.flags = flags;
3043 cb.policy_cb = policy_cb_data;
3044 cb.should_prune_fn = should_prune_fn;
3045
3046 /*
3047 * The reflog file is locked by holding the lock on the
3048 * reference itself, plus we might need to update the
3049 * reference if --updateref was specified:
3050 */
4f01e508 3051 lock = lock_ref_oid_basic(refs, refname, oid,
91774afc 3052 NULL, NULL, REF_NO_DEREF,
4f01e508 3053 &type, &err);
7bd9bcf3
MH
3054 if (!lock) {
3055 error("cannot lock ref '%s': %s", refname, err.buf);
3056 strbuf_release(&err);
3057 return -1;
3058 }
2f40e954 3059 if (!refs_reflog_exists(ref_store, refname)) {
7bd9bcf3
MH
3060 unlock_ref(lock);
3061 return 0;
3062 }
3063
802de3da
NTND
3064 files_reflog_path(refs, &log_file_sb, refname);
3065 log_file = strbuf_detach(&log_file_sb, NULL);
7bd9bcf3
MH
3066 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3067 /*
3068 * Even though holding $GIT_DIR/logs/$reflog.lock has
3069 * no locking implications, we use the lock_file
3070 * machinery here anyway because it does a lot of the
3071 * work we need, including cleaning up if the program
3072 * exits unexpectedly.
3073 */
3074 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
3075 struct strbuf err = STRBUF_INIT;
3076 unable_to_lock_message(log_file, errno, &err);
3077 error("%s", err.buf);
3078 strbuf_release(&err);
3079 goto failure;
3080 }
3081 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
3082 if (!cb.newlog) {
3083 error("cannot fdopen %s (%s)",
3084 get_lock_file_path(&reflog_lock), strerror(errno));
3085 goto failure;
3086 }
3087 }
3088
0155f710 3089 (*prepare_fn)(refname, oid, cb.policy_cb);
2f40e954 3090 refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
7bd9bcf3
MH
3091 (*cleanup_fn)(cb.policy_cb);
3092
3093 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3094 /*
3095 * It doesn't make sense to adjust a reference pointed
3096 * to by a symbolic ref based on expiring entries in
3097 * the symbolic reference's reflog. Nor can we update
3098 * a reference if there are no remaining reflog
3099 * entries.
3100 */
3101 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
3102 !(type & REF_ISSYMREF) &&
9461d272 3103 !is_null_oid(&cb.last_kept_oid);
7bd9bcf3 3104
83a3069a 3105 if (close_lock_file_gently(&reflog_lock)) {
7bd9bcf3
MH
3106 status |= error("couldn't write %s: %s", log_file,
3107 strerror(errno));
83a3069a 3108 rollback_lock_file(&reflog_lock);
7bd9bcf3 3109 } else if (update &&
ee4d8e45 3110 (write_in_full(get_lock_file_fd(&lock->lk),
2ae2e2a1 3111 oid_to_hex(&cb.last_kept_oid), the_hash_algo->hexsz) < 0 ||
88780c37 3112 write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 ||
83a3069a 3113 close_ref_gently(lock) < 0)) {
7bd9bcf3 3114 status |= error("couldn't write %s",
ee4d8e45 3115 get_lock_file_path(&lock->lk));
7bd9bcf3
MH
3116 rollback_lock_file(&reflog_lock);
3117 } else if (commit_lock_file(&reflog_lock)) {
e0048d3e 3118 status |= error("unable to write reflog '%s' (%s)",
7bd9bcf3
MH
3119 log_file, strerror(errno));
3120 } else if (update && commit_ref(lock)) {
3121 status |= error("couldn't set %s", lock->ref_name);
3122 }
3123 }
3124 free(log_file);
3125 unlock_ref(lock);
3126 return status;
3127
3128 failure:
3129 rollback_lock_file(&reflog_lock);
3130 free(log_file);
3131 unlock_ref(lock);
3132 return -1;
3133}
3dce444f 3134
6fb5acfd
DT
3135static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
3136{
19e02f4f 3137 struct files_ref_store *refs =
9e7ec634 3138 files_downcast(ref_store, REF_STORE_WRITE, "init_db");
e9dcc305
NTND
3139 struct strbuf sb = STRBUF_INIT;
3140
6fb5acfd
DT
3141 /*
3142 * Create .git/refs/{heads,tags}
3143 */
19e02f4f 3144 files_ref_path(refs, &sb, "refs/heads");
e9dcc305
NTND
3145 safe_create_dir(sb.buf, 1);
3146
3147 strbuf_reset(&sb);
19e02f4f 3148 files_ref_path(refs, &sb, "refs/tags");
e9dcc305
NTND
3149 safe_create_dir(sb.buf, 1);
3150
3151 strbuf_release(&sb);
6fb5acfd
DT
3152 return 0;
3153}
3154
3dce444f
RS
3155struct ref_storage_be refs_be_files = {
3156 NULL,
00eebe35 3157 "files",
127b42a1 3158 files_ref_store_create,
6fb5acfd 3159 files_init_db,
30173b88
MH
3160 files_transaction_prepare,
3161 files_transaction_finish,
3162 files_transaction_abort,
fc681463 3163 files_initial_transaction_commit,
e1e33b72 3164
8231527e 3165 files_pack_refs,
284689ba 3166 files_create_symref,
a27dcf89 3167 files_delete_refs,
9b6b40d9 3168 files_rename_ref,
52d59cc6 3169 files_copy_ref,
8231527e 3170
1a769003 3171 files_ref_iterator_begin,
62665823 3172 files_read_raw_ref,
e3688bd6
DT
3173
3174 files_reflog_iterator_begin,
3175 files_for_each_reflog_ent,
3176 files_for_each_reflog_ent_reverse,
3177 files_reflog_exists,
3178 files_create_reflog,
3179 files_delete_reflog,
3180 files_reflog_expire
3dce444f 3181};