get_loose_ref_cache(): new function
[git/git.git] / refs / files-backend.c
CommitLineData
7bd9bcf3
MH
1#include "../cache.h"
2#include "../refs.h"
3#include "refs-internal.h"
958f9646 4#include "ref-cache.h"
3bc581b9 5#include "../iterator.h"
2880d16f 6#include "../dir-iterator.h"
7bd9bcf3
MH
7#include "../lockfile.h"
8#include "../object.h"
9#include "../dir.h"
10
11struct ref_lock {
12 char *ref_name;
7bd9bcf3
MH
13 struct lock_file *lk;
14 struct object_id old_oid;
15};
16
7bd9bcf3 17/*
a8739244
MH
18 * Return true if refname, which has the specified oid and flags, can
19 * be resolved to an object in the database. If the referred-to object
20 * does not exist, emit a warning and return false.
7bd9bcf3 21 */
a8739244
MH
22static int ref_resolves_to_object(const char *refname,
23 const struct object_id *oid,
24 unsigned int flags)
7bd9bcf3 25{
a8739244 26 if (flags & REF_ISBROKEN)
7bd9bcf3 27 return 0;
a8739244
MH
28 if (!has_sha1_file(oid->hash)) {
29 error("%s does not point to a valid object!", refname);
7bd9bcf3
MH
30 return 0;
31 }
32 return 1;
33}
34
35/*
a8739244
MH
36 * Return true if the reference described by entry can be resolved to
37 * an object in the database; otherwise, emit a warning and return
38 * false.
7bd9bcf3 39 */
a8739244 40static int entry_resolves_to_object(struct ref_entry *entry)
7bd9bcf3 41{
a8739244
MH
42 return ref_resolves_to_object(entry->name,
43 &entry->u.value.oid, entry->flag);
7bd9bcf3
MH
44}
45
7bd9bcf3 46struct packed_ref_cache {
7c22bc8a 47 struct ref_cache *cache;
7bd9bcf3
MH
48
49 /*
50 * Count of references to the data structure in this instance,
65a0a8e5
MH
51 * including the pointer from files_ref_store::packed if any.
52 * The data will not be freed as long as the reference count
53 * is nonzero.
7bd9bcf3
MH
54 */
55 unsigned int referrers;
56
57 /*
58 * Iff the packed-refs file associated with this instance is
59 * currently locked for writing, this points at the associated
60 * lock (which is owned by somebody else). The referrer count
61 * is also incremented when the file is locked and decremented
62 * when it is unlocked.
63 */
64 struct lock_file *lock;
65
66 /* The metadata from when this packed-refs cache was read */
67 struct stat_validity validity;
68};
69
70/*
71 * Future: need to be in "struct repository"
72 * when doing a full libification.
73 */
00eebe35
MH
74struct files_ref_store {
75 struct ref_store base;
9e7ec634 76 unsigned int store_flags;
32c597e7 77
f57f37e2
NTND
78 char *gitdir;
79 char *gitcommondir;
33dfb9f3
NTND
80 char *packed_refs_path;
81
7c22bc8a 82 struct ref_cache *loose;
7bd9bcf3 83 struct packed_ref_cache *packed;
00eebe35 84};
7bd9bcf3
MH
85
86/* Lock used for the main packed-refs file: */
87static struct lock_file packlock;
88
89/*
90 * Increment the reference count of *packed_refs.
91 */
92static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
93{
94 packed_refs->referrers++;
95}
96
97/*
98 * Decrease the reference count of *packed_refs. If it goes to zero,
99 * free *packed_refs and return true; otherwise return false.
100 */
101static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
102{
103 if (!--packed_refs->referrers) {
7c22bc8a 104 free_ref_cache(packed_refs->cache);
7bd9bcf3
MH
105 stat_validity_clear(&packed_refs->validity);
106 free(packed_refs);
107 return 1;
108 } else {
109 return 0;
110 }
111}
112
65a0a8e5 113static void clear_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
114{
115 if (refs->packed) {
116 struct packed_ref_cache *packed_refs = refs->packed;
117
118 if (packed_refs->lock)
119 die("internal error: packed-ref cache cleared while locked");
120 refs->packed = NULL;
121 release_packed_ref_cache(packed_refs);
122 }
123}
124
65a0a8e5 125static void clear_loose_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
126{
127 if (refs->loose) {
7c22bc8a 128 free_ref_cache(refs->loose);
7bd9bcf3
MH
129 refs->loose = NULL;
130 }
131}
132
a2d5156c
JK
133/*
134 * Create a new submodule ref cache and add it to the internal
135 * set of caches.
136 */
9e7ec634
NTND
137static struct ref_store *files_ref_store_create(const char *gitdir,
138 unsigned int flags)
7bd9bcf3 139{
00eebe35
MH
140 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
141 struct ref_store *ref_store = (struct ref_store *)refs;
f57f37e2 142 struct strbuf sb = STRBUF_INIT;
7bd9bcf3 143
fbfd0a29 144 base_ref_store_init(ref_store, &refs_be_files);
9e7ec634 145 refs->store_flags = flags;
7bd9bcf3 146
f57f37e2
NTND
147 refs->gitdir = xstrdup(gitdir);
148 get_common_dir_noenv(&sb, gitdir);
149 refs->gitcommondir = strbuf_detach(&sb, NULL);
150 strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
151 refs->packed_refs_path = strbuf_detach(&sb, NULL);
7bd9bcf3 152
00eebe35 153 return ref_store;
a2d5156c 154}
7bd9bcf3 155
32c597e7 156/*
9e7ec634
NTND
157 * Die if refs is not the main ref store. caller is used in any
158 * necessary error messages.
32c597e7
MH
159 */
160static void files_assert_main_repository(struct files_ref_store *refs,
161 const char *caller)
162{
9e7ec634
NTND
163 if (refs->store_flags & REF_STORE_MAIN)
164 return;
165
166 die("BUG: operation %s only allowed for main ref store", caller);
32c597e7
MH
167}
168
a2d5156c 169/*
00eebe35 170 * Downcast ref_store to files_ref_store. Die if ref_store is not a
9e7ec634
NTND
171 * files_ref_store. required_flags is compared with ref_store's
172 * store_flags to ensure the ref_store has all required capabilities.
173 * "caller" is used in any necessary error messages.
a2d5156c 174 */
9e7ec634
NTND
175static struct files_ref_store *files_downcast(struct ref_store *ref_store,
176 unsigned int required_flags,
177 const char *caller)
a2d5156c 178{
32c597e7
MH
179 struct files_ref_store *refs;
180
00eebe35
MH
181 if (ref_store->be != &refs_be_files)
182 die("BUG: ref_store is type \"%s\" not \"files\" in %s",
183 ref_store->be->name, caller);
2eed2780 184
32c597e7
MH
185 refs = (struct files_ref_store *)ref_store;
186
9e7ec634
NTND
187 if ((refs->store_flags & required_flags) != required_flags)
188 die("BUG: operation %s requires abilities 0x%x, but only have 0x%x",
189 caller, required_flags, refs->store_flags);
2eed2780 190
32c597e7 191 return refs;
7bd9bcf3
MH
192}
193
194/* The length of a peeled reference line in packed-refs, including EOL: */
195#define PEELED_LINE_LENGTH 42
196
197/*
198 * The packed-refs header line that we write out. Perhaps other
199 * traits will be added later. The trailing space is required.
200 */
201static const char PACKED_REFS_HEADER[] =
202 "# pack-refs with: peeled fully-peeled \n";
203
204/*
205 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
206 * Return a pointer to the refname within the line (null-terminated),
207 * or NULL if there was a problem.
208 */
209static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
210{
211 const char *ref;
212
213 /*
214 * 42: the answer to everything.
215 *
216 * In this case, it happens to be the answer to
217 * 40 (length of sha1 hex representation)
218 * +1 (space in between hex and name)
219 * +1 (newline at the end of the line)
220 */
221 if (line->len <= 42)
222 return NULL;
223
224 if (get_sha1_hex(line->buf, sha1) < 0)
225 return NULL;
226 if (!isspace(line->buf[40]))
227 return NULL;
228
229 ref = line->buf + 41;
230 if (isspace(*ref))
231 return NULL;
232
233 if (line->buf[line->len - 1] != '\n')
234 return NULL;
235 line->buf[--line->len] = 0;
236
237 return ref;
238}
239
240/*
241 * Read f, which is a packed-refs file, into dir.
242 *
243 * A comment line of the form "# pack-refs with: " may contain zero or
244 * more traits. We interpret the traits as follows:
245 *
246 * No traits:
247 *
248 * Probably no references are peeled. But if the file contains a
249 * peeled value for a reference, we will use it.
250 *
251 * peeled:
252 *
253 * References under "refs/tags/", if they *can* be peeled, *are*
254 * peeled in this file. References outside of "refs/tags/" are
255 * probably not peeled even if they could have been, but if we find
256 * a peeled value for such a reference we will use it.
257 *
258 * fully-peeled:
259 *
260 * All references in the file that can be peeled are peeled.
261 * Inversely (and this is more important), any references in the
262 * file for which no peeled value is recorded is not peelable. This
263 * trait should typically be written alongside "peeled" for
264 * compatibility with older clients, but we do not require it
265 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
266 */
267static void read_packed_refs(FILE *f, struct ref_dir *dir)
268{
269 struct ref_entry *last = NULL;
270 struct strbuf line = STRBUF_INIT;
271 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
272
273 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
274 unsigned char sha1[20];
275 const char *refname;
276 const char *traits;
277
278 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
279 if (strstr(traits, " fully-peeled "))
280 peeled = PEELED_FULLY;
281 else if (strstr(traits, " peeled "))
282 peeled = PEELED_TAGS;
283 /* perhaps other traits later as well */
284 continue;
285 }
286
287 refname = parse_ref_line(&line, sha1);
288 if (refname) {
289 int flag = REF_ISPACKED;
290
291 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
292 if (!refname_is_safe(refname))
293 die("packed refname is dangerous: %s", refname);
294 hashclr(sha1);
295 flag |= REF_BAD_NAME | REF_ISBROKEN;
296 }
297 last = create_ref_entry(refname, sha1, flag, 0);
298 if (peeled == PEELED_FULLY ||
299 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
300 last->flag |= REF_KNOWS_PEELED;
a3ade2ba 301 add_ref_entry(dir, last);
7bd9bcf3
MH
302 continue;
303 }
304 if (last &&
305 line.buf[0] == '^' &&
306 line.len == PEELED_LINE_LENGTH &&
307 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
308 !get_sha1_hex(line.buf + 1, sha1)) {
309 hashcpy(last->u.value.peeled.hash, sha1);
310 /*
311 * Regardless of what the file header said,
312 * we definitely know the value of *this*
313 * reference:
314 */
315 last->flag |= REF_KNOWS_PEELED;
316 }
317 }
318
319 strbuf_release(&line);
320}
321
33dfb9f3
NTND
322static const char *files_packed_refs_path(struct files_ref_store *refs)
323{
324 return refs->packed_refs_path;
325}
326
802de3da
NTND
327static void files_reflog_path(struct files_ref_store *refs,
328 struct strbuf *sb,
329 const char *refname)
330{
331 if (!refname) {
f57f37e2
NTND
332 /*
333 * FIXME: of course this is wrong in multi worktree
334 * setting. To be fixed real soon.
335 */
336 strbuf_addf(sb, "%s/logs", refs->gitcommondir);
802de3da
NTND
337 return;
338 }
339
f57f37e2
NTND
340 switch (ref_type(refname)) {
341 case REF_TYPE_PER_WORKTREE:
342 case REF_TYPE_PSEUDOREF:
343 strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
344 break;
345 case REF_TYPE_NORMAL:
346 strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
347 break;
348 default:
349 die("BUG: unknown ref type %d of ref %s",
350 ref_type(refname), refname);
351 }
802de3da
NTND
352}
353
19e02f4f
NTND
354static void files_ref_path(struct files_ref_store *refs,
355 struct strbuf *sb,
356 const char *refname)
357{
f57f37e2
NTND
358 switch (ref_type(refname)) {
359 case REF_TYPE_PER_WORKTREE:
360 case REF_TYPE_PSEUDOREF:
361 strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
362 break;
363 case REF_TYPE_NORMAL:
364 strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
365 break;
366 default:
367 die("BUG: unknown ref type %d of ref %s",
368 ref_type(refname), refname);
369 }
19e02f4f
NTND
370}
371
7bd9bcf3 372/*
65a0a8e5
MH
373 * Get the packed_ref_cache for the specified files_ref_store,
374 * creating it if necessary.
7bd9bcf3 375 */
65a0a8e5 376static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3 377{
33dfb9f3 378 const char *packed_refs_file = files_packed_refs_path(refs);
7bd9bcf3
MH
379
380 if (refs->packed &&
381 !stat_validity_check(&refs->packed->validity, packed_refs_file))
382 clear_packed_ref_cache(refs);
383
384 if (!refs->packed) {
385 FILE *f;
386
387 refs->packed = xcalloc(1, sizeof(*refs->packed));
388 acquire_packed_ref_cache(refs->packed);
df308759 389 refs->packed->cache = create_ref_cache(&refs->base, NULL);
7c22bc8a 390 refs->packed->cache->root->flag &= ~REF_INCOMPLETE;
7bd9bcf3
MH
391 f = fopen(packed_refs_file, "r");
392 if (f) {
393 stat_validity_update(&refs->packed->validity, fileno(f));
7c22bc8a 394 read_packed_refs(f, get_ref_dir(refs->packed->cache->root));
7bd9bcf3
MH
395 fclose(f);
396 }
397 }
7bd9bcf3
MH
398 return refs->packed;
399}
400
401static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
402{
7c22bc8a 403 return get_ref_dir(packed_ref_cache->cache->root);
7bd9bcf3
MH
404}
405
65a0a8e5 406static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
407{
408 return get_packed_ref_dir(get_packed_ref_cache(refs));
409}
410
411/*
412 * Add a reference to the in-memory packed reference cache. This may
413 * only be called while the packed-refs file is locked (see
414 * lock_packed_refs()). To actually write the packed-refs file, call
415 * commit_packed_refs().
416 */
d99825ab
MH
417static void add_packed_ref(struct files_ref_store *refs,
418 const char *refname, const unsigned char *sha1)
7bd9bcf3 419{
00eebe35 420 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
421
422 if (!packed_ref_cache->lock)
423 die("internal error: packed refs not locked");
a3ade2ba 424 add_ref_entry(get_packed_ref_dir(packed_ref_cache),
958f9646 425 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
7bd9bcf3
MH
426}
427
428/*
429 * Read the loose references from the namespace dirname into dir
430 * (without recursing). dirname must end with '/'. dir must be the
431 * directory entry corresponding to dirname.
432 */
df308759
MH
433static void loose_fill_ref_dir(struct ref_store *ref_store,
434 struct ref_dir *dir, const char *dirname)
7bd9bcf3 435{
df308759
MH
436 struct files_ref_store *refs =
437 files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
7bd9bcf3
MH
438 DIR *d;
439 struct dirent *de;
440 int dirnamelen = strlen(dirname);
441 struct strbuf refname;
442 struct strbuf path = STRBUF_INIT;
443 size_t path_baselen;
444
19e02f4f 445 files_ref_path(refs, &path, dirname);
7bd9bcf3
MH
446 path_baselen = path.len;
447
448 d = opendir(path.buf);
449 if (!d) {
450 strbuf_release(&path);
451 return;
452 }
453
454 strbuf_init(&refname, dirnamelen + 257);
455 strbuf_add(&refname, dirname, dirnamelen);
456
457 while ((de = readdir(d)) != NULL) {
458 unsigned char sha1[20];
459 struct stat st;
460 int flag;
461
462 if (de->d_name[0] == '.')
463 continue;
464 if (ends_with(de->d_name, ".lock"))
465 continue;
466 strbuf_addstr(&refname, de->d_name);
467 strbuf_addstr(&path, de->d_name);
468 if (stat(path.buf, &st) < 0) {
469 ; /* silently ignore */
470 } else if (S_ISDIR(st.st_mode)) {
471 strbuf_addch(&refname, '/');
472 add_entry_to_dir(dir,
e00d1a4f 473 create_dir_entry(dir->cache, refname.buf,
7bd9bcf3
MH
474 refname.len, 1));
475 } else {
7d2df051 476 if (!refs_resolve_ref_unsafe(&refs->base,
3c0cb0cb
MH
477 refname.buf,
478 RESOLVE_REF_READING,
479 sha1, &flag)) {
7bd9bcf3
MH
480 hashclr(sha1);
481 flag |= REF_ISBROKEN;
482 } else if (is_null_sha1(sha1)) {
483 /*
484 * It is so astronomically unlikely
485 * that NULL_SHA1 is the SHA-1 of an
486 * actual object that we consider its
487 * appearance in a loose reference
488 * file to be repo corruption
489 * (probably due to a software bug).
490 */
491 flag |= REF_ISBROKEN;
492 }
493
494 if (check_refname_format(refname.buf,
495 REFNAME_ALLOW_ONELEVEL)) {
496 if (!refname_is_safe(refname.buf))
497 die("loose refname is dangerous: %s", refname.buf);
498 hashclr(sha1);
499 flag |= REF_BAD_NAME | REF_ISBROKEN;
500 }
501 add_entry_to_dir(dir,
502 create_ref_entry(refname.buf, sha1, flag, 0));
503 }
504 strbuf_setlen(&refname, dirnamelen);
505 strbuf_setlen(&path, path_baselen);
506 }
507 strbuf_release(&refname);
508 strbuf_release(&path);
509 closedir(d);
e3bf2989
MH
510
511 /*
512 * Manually add refs/bisect, which, being per-worktree, might
513 * not appear in the directory listing for refs/ in the main
514 * repo.
515 */
516 if (!strcmp(dirname, "refs/")) {
517 int pos = search_ref_dir(dir, "refs/bisect/", 12);
518
519 if (pos < 0) {
520 struct ref_entry *child_entry = create_dir_entry(
521 dir->cache, "refs/bisect/", 12, 1);
522 add_entry_to_dir(dir, child_entry);
523 }
524 }
7bd9bcf3
MH
525}
526
a714b19c 527static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
528{
529 if (!refs->loose) {
530 /*
531 * Mark the top-level directory complete because we
532 * are about to read the only subdirectory that can
533 * hold references:
534 */
df308759 535 refs->loose = create_ref_cache(&refs->base, loose_fill_ref_dir);
7c22bc8a
MH
536
537 /* We're going to fill the top level ourselves: */
538 refs->loose->root->flag &= ~REF_INCOMPLETE;
539
7bd9bcf3 540 /*
7c22bc8a
MH
541 * Add an incomplete entry for "refs/" (to be filled
542 * lazily):
7bd9bcf3 543 */
7c22bc8a 544 add_entry_to_dir(get_ref_dir(refs->loose->root),
e00d1a4f 545 create_dir_entry(refs->loose, "refs/", 5, 1));
7bd9bcf3 546 }
a714b19c
MH
547 return refs->loose;
548}
549
550static struct ref_dir *get_loose_ref_dir(struct files_ref_store *refs)
551{
552 return get_ref_dir(get_loose_ref_cache(refs)->root);
7bd9bcf3
MH
553}
554
7bd9bcf3
MH
555/*
556 * Return the ref_entry for the given refname from the packed
557 * references. If it does not exist, return NULL.
558 */
f0d21efc
MH
559static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
560 const char *refname)
7bd9bcf3 561{
bc1c696e 562 return find_ref_entry(get_packed_refs(refs), refname);
7bd9bcf3
MH
563}
564
565/*
419c6f4c 566 * A loose ref file doesn't exist; check for a packed ref.
7bd9bcf3 567 */
611118d0
MH
568static int resolve_packed_ref(struct files_ref_store *refs,
569 const char *refname,
570 unsigned char *sha1, unsigned int *flags)
7bd9bcf3
MH
571{
572 struct ref_entry *entry;
573
574 /*
575 * The loose reference file does not exist; check for a packed
576 * reference.
577 */
f0d21efc 578 entry = get_packed_ref(refs, refname);
7bd9bcf3
MH
579 if (entry) {
580 hashcpy(sha1, entry->u.value.oid.hash);
a70a93b7 581 *flags |= REF_ISPACKED;
7bd9bcf3
MH
582 return 0;
583 }
419c6f4c
MH
584 /* refname is not a packed reference. */
585 return -1;
7bd9bcf3
MH
586}
587
e1e33b72
MH
588static int files_read_raw_ref(struct ref_store *ref_store,
589 const char *refname, unsigned char *sha1,
590 struct strbuf *referent, unsigned int *type)
7bd9bcf3 591{
4308651c 592 struct files_ref_store *refs =
9e7ec634 593 files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
42a38cf7
MH
594 struct strbuf sb_contents = STRBUF_INIT;
595 struct strbuf sb_path = STRBUF_INIT;
7048653a
DT
596 const char *path;
597 const char *buf;
598 struct stat st;
599 int fd;
42a38cf7
MH
600 int ret = -1;
601 int save_errno;
e8c42cb9 602 int remaining_retries = 3;
7bd9bcf3 603
fa96ea1b 604 *type = 0;
42a38cf7 605 strbuf_reset(&sb_path);
34c7ad8f 606
19e02f4f 607 files_ref_path(refs, &sb_path, refname);
34c7ad8f 608
42a38cf7 609 path = sb_path.buf;
7bd9bcf3 610
7048653a
DT
611stat_ref:
612 /*
613 * We might have to loop back here to avoid a race
614 * condition: first we lstat() the file, then we try
615 * to read it as a link or as a file. But if somebody
616 * changes the type of the file (file <-> directory
617 * <-> symlink) between the lstat() and reading, then
618 * we don't want to report that as an error but rather
619 * try again starting with the lstat().
e8c42cb9
JK
620 *
621 * We'll keep a count of the retries, though, just to avoid
622 * any confusing situation sending us into an infinite loop.
7048653a 623 */
7bd9bcf3 624
e8c42cb9
JK
625 if (remaining_retries-- <= 0)
626 goto out;
627
7048653a
DT
628 if (lstat(path, &st) < 0) {
629 if (errno != ENOENT)
42a38cf7 630 goto out;
611118d0 631 if (resolve_packed_ref(refs, refname, sha1, type)) {
7048653a 632 errno = ENOENT;
42a38cf7 633 goto out;
7bd9bcf3 634 }
42a38cf7
MH
635 ret = 0;
636 goto out;
7bd9bcf3 637 }
7bd9bcf3 638
7048653a
DT
639 /* Follow "normalized" - ie "refs/.." symlinks by hand */
640 if (S_ISLNK(st.st_mode)) {
42a38cf7
MH
641 strbuf_reset(&sb_contents);
642 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
7048653a 643 if (errno == ENOENT || errno == EINVAL)
7bd9bcf3
MH
644 /* inconsistent with lstat; retry */
645 goto stat_ref;
646 else
42a38cf7 647 goto out;
7bd9bcf3 648 }
42a38cf7
MH
649 if (starts_with(sb_contents.buf, "refs/") &&
650 !check_refname_format(sb_contents.buf, 0)) {
92b38093 651 strbuf_swap(&sb_contents, referent);
3a0b6b9a 652 *type |= REF_ISSYMREF;
42a38cf7
MH
653 ret = 0;
654 goto out;
7bd9bcf3 655 }
3f7bd767
JK
656 /*
657 * It doesn't look like a refname; fall through to just
658 * treating it like a non-symlink, and reading whatever it
659 * points to.
660 */
7048653a 661 }
7bd9bcf3 662
7048653a
DT
663 /* Is it a directory? */
664 if (S_ISDIR(st.st_mode)) {
e167a567
MH
665 /*
666 * Even though there is a directory where the loose
667 * ref is supposed to be, there could still be a
668 * packed ref:
669 */
611118d0 670 if (resolve_packed_ref(refs, refname, sha1, type)) {
e167a567
MH
671 errno = EISDIR;
672 goto out;
673 }
674 ret = 0;
42a38cf7 675 goto out;
7048653a
DT
676 }
677
678 /*
679 * Anything else, just open it and try to use it as
680 * a ref
681 */
682 fd = open(path, O_RDONLY);
683 if (fd < 0) {
3f7bd767 684 if (errno == ENOENT && !S_ISLNK(st.st_mode))
7048653a
DT
685 /* inconsistent with lstat; retry */
686 goto stat_ref;
687 else
42a38cf7 688 goto out;
7048653a 689 }
42a38cf7
MH
690 strbuf_reset(&sb_contents);
691 if (strbuf_read(&sb_contents, fd, 256) < 0) {
7048653a
DT
692 int save_errno = errno;
693 close(fd);
694 errno = save_errno;
42a38cf7 695 goto out;
7048653a
DT
696 }
697 close(fd);
42a38cf7
MH
698 strbuf_rtrim(&sb_contents);
699 buf = sb_contents.buf;
7048653a
DT
700 if (starts_with(buf, "ref:")) {
701 buf += 4;
7bd9bcf3
MH
702 while (isspace(*buf))
703 buf++;
7048653a 704
92b38093
MH
705 strbuf_reset(referent);
706 strbuf_addstr(referent, buf);
3a0b6b9a 707 *type |= REF_ISSYMREF;
42a38cf7
MH
708 ret = 0;
709 goto out;
7bd9bcf3 710 }
7bd9bcf3 711
7048653a
DT
712 /*
713 * Please note that FETCH_HEAD has additional
714 * data after the sha.
715 */
716 if (get_sha1_hex(buf, sha1) ||
717 (buf[40] != '\0' && !isspace(buf[40]))) {
3a0b6b9a 718 *type |= REF_ISBROKEN;
7048653a 719 errno = EINVAL;
42a38cf7 720 goto out;
7048653a
DT
721 }
722
42a38cf7 723 ret = 0;
7bd9bcf3 724
42a38cf7
MH
725out:
726 save_errno = errno;
7bd9bcf3
MH
727 strbuf_release(&sb_path);
728 strbuf_release(&sb_contents);
42a38cf7 729 errno = save_errno;
7bd9bcf3
MH
730 return ret;
731}
732
8415d247
MH
733static void unlock_ref(struct ref_lock *lock)
734{
735 /* Do not free lock->lk -- atexit() still looks at them */
736 if (lock->lk)
737 rollback_lock_file(lock->lk);
738 free(lock->ref_name);
8415d247
MH
739 free(lock);
740}
741
92b1551b
MH
742/*
743 * Lock refname, without following symrefs, and set *lock_p to point
744 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
745 * and type similarly to read_raw_ref().
746 *
747 * The caller must verify that refname is a "safe" reference name (in
748 * the sense of refname_is_safe()) before calling this function.
749 *
750 * If the reference doesn't already exist, verify that refname doesn't
751 * have a D/F conflict with any existing references. extras and skip
524a9fdb 752 * are passed to refs_verify_refname_available() for this check.
92b1551b
MH
753 *
754 * If mustexist is not set and the reference is not found or is
755 * broken, lock the reference anyway but clear sha1.
756 *
757 * Return 0 on success. On failure, write an error message to err and
758 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
759 *
760 * Implementation note: This function is basically
761 *
762 * lock reference
763 * read_raw_ref()
764 *
765 * but it includes a lot more code to
766 * - Deal with possible races with other processes
524a9fdb 767 * - Avoid calling refs_verify_refname_available() when it can be
92b1551b
MH
768 * avoided, namely if we were successfully able to read the ref
769 * - Generate informative error messages in the case of failure
770 */
f7b0a987
MH
771static int lock_raw_ref(struct files_ref_store *refs,
772 const char *refname, int mustexist,
92b1551b
MH
773 const struct string_list *extras,
774 const struct string_list *skip,
775 struct ref_lock **lock_p,
776 struct strbuf *referent,
777 unsigned int *type,
778 struct strbuf *err)
779{
780 struct ref_lock *lock;
781 struct strbuf ref_file = STRBUF_INIT;
782 int attempts_remaining = 3;
783 int ret = TRANSACTION_GENERIC_ERROR;
784
785 assert(err);
32c597e7 786 files_assert_main_repository(refs, "lock_raw_ref");
f7b0a987 787
92b1551b
MH
788 *type = 0;
789
790 /* First lock the file so it can't change out from under us. */
791
792 *lock_p = lock = xcalloc(1, sizeof(*lock));
793
794 lock->ref_name = xstrdup(refname);
19e02f4f 795 files_ref_path(refs, &ref_file, refname);
92b1551b
MH
796
797retry:
798 switch (safe_create_leading_directories(ref_file.buf)) {
799 case SCLD_OK:
800 break; /* success */
801 case SCLD_EXISTS:
802 /*
803 * Suppose refname is "refs/foo/bar". We just failed
804 * to create the containing directory, "refs/foo",
805 * because there was a non-directory in the way. This
806 * indicates a D/F conflict, probably because of
807 * another reference such as "refs/foo". There is no
808 * reason to expect this error to be transitory.
809 */
7d2df051
NTND
810 if (refs_verify_refname_available(&refs->base, refname,
811 extras, skip, err)) {
92b1551b
MH
812 if (mustexist) {
813 /*
814 * To the user the relevant error is
815 * that the "mustexist" reference is
816 * missing:
817 */
818 strbuf_reset(err);
819 strbuf_addf(err, "unable to resolve reference '%s'",
820 refname);
821 } else {
822 /*
823 * The error message set by
524a9fdb
MH
824 * refs_verify_refname_available() is
825 * OK.
92b1551b
MH
826 */
827 ret = TRANSACTION_NAME_CONFLICT;
828 }
829 } else {
830 /*
831 * The file that is in the way isn't a loose
832 * reference. Report it as a low-level
833 * failure.
834 */
835 strbuf_addf(err, "unable to create lock file %s.lock; "
836 "non-directory in the way",
837 ref_file.buf);
838 }
839 goto error_return;
840 case SCLD_VANISHED:
841 /* Maybe another process was tidying up. Try again. */
842 if (--attempts_remaining > 0)
843 goto retry;
844 /* fall through */
845 default:
846 strbuf_addf(err, "unable to create directory for %s",
847 ref_file.buf);
848 goto error_return;
849 }
850
851 if (!lock->lk)
852 lock->lk = xcalloc(1, sizeof(struct lock_file));
853
854 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
855 if (errno == ENOENT && --attempts_remaining > 0) {
856 /*
857 * Maybe somebody just deleted one of the
858 * directories leading to ref_file. Try
859 * again:
860 */
861 goto retry;
862 } else {
863 unable_to_lock_message(ref_file.buf, errno, err);
864 goto error_return;
865 }
866 }
867
868 /*
869 * Now we hold the lock and can read the reference without
870 * fear that its value will change.
871 */
872
f7b0a987 873 if (files_read_raw_ref(&refs->base, refname,
e1e33b72 874 lock->old_oid.hash, referent, type)) {
92b1551b
MH
875 if (errno == ENOENT) {
876 if (mustexist) {
877 /* Garden variety missing reference. */
878 strbuf_addf(err, "unable to resolve reference '%s'",
879 refname);
880 goto error_return;
881 } else {
882 /*
883 * Reference is missing, but that's OK. We
884 * know that there is not a conflict with
885 * another loose reference because
886 * (supposing that we are trying to lock
887 * reference "refs/foo/bar"):
888 *
889 * - We were successfully able to create
890 * the lockfile refs/foo/bar.lock, so we
891 * know there cannot be a loose reference
892 * named "refs/foo".
893 *
894 * - We got ENOENT and not EISDIR, so we
895 * know that there cannot be a loose
896 * reference named "refs/foo/bar/baz".
897 */
898 }
899 } else if (errno == EISDIR) {
900 /*
901 * There is a directory in the way. It might have
902 * contained references that have been deleted. If
903 * we don't require that the reference already
904 * exists, try to remove the directory so that it
905 * doesn't cause trouble when we want to rename the
906 * lockfile into place later.
907 */
908 if (mustexist) {
909 /* Garden variety missing reference. */
910 strbuf_addf(err, "unable to resolve reference '%s'",
911 refname);
912 goto error_return;
913 } else if (remove_dir_recursively(&ref_file,
914 REMOVE_DIR_EMPTY_ONLY)) {
b05855b5
MH
915 if (refs_verify_refname_available(
916 &refs->base, refname,
917 extras, skip, err)) {
92b1551b
MH
918 /*
919 * The error message set by
920 * verify_refname_available() is OK.
921 */
922 ret = TRANSACTION_NAME_CONFLICT;
923 goto error_return;
924 } else {
925 /*
926 * We can't delete the directory,
927 * but we also don't know of any
928 * references that it should
929 * contain.
930 */
931 strbuf_addf(err, "there is a non-empty directory '%s' "
932 "blocking reference '%s'",
933 ref_file.buf, refname);
934 goto error_return;
935 }
936 }
937 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
938 strbuf_addf(err, "unable to resolve reference '%s': "
939 "reference broken", refname);
940 goto error_return;
941 } else {
942 strbuf_addf(err, "unable to resolve reference '%s': %s",
943 refname, strerror(errno));
944 goto error_return;
945 }
946
947 /*
948 * If the ref did not exist and we are creating it,
524a9fdb
MH
949 * make sure there is no existing ref that conflicts
950 * with refname:
92b1551b 951 */
524a9fdb
MH
952 if (refs_verify_refname_available(
953 &refs->base, refname,
954 extras, skip, err))
92b1551b 955 goto error_return;
92b1551b
MH
956 }
957
958 ret = 0;
959 goto out;
960
961error_return:
962 unlock_ref(lock);
963 *lock_p = NULL;
964
965out:
966 strbuf_release(&ref_file);
967 return ret;
968}
969
bd427cf2
MH
970static int files_peel_ref(struct ref_store *ref_store,
971 const char *refname, unsigned char *sha1)
7bd9bcf3 972{
9e7ec634
NTND
973 struct files_ref_store *refs =
974 files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
975 "peel_ref");
7bd9bcf3
MH
976 int flag;
977 unsigned char base[20];
978
4c4de895
MH
979 if (current_ref_iter && current_ref_iter->refname == refname) {
980 struct object_id peeled;
981
982 if (ref_iterator_peel(current_ref_iter, &peeled))
7bd9bcf3 983 return -1;
4c4de895 984 hashcpy(sha1, peeled.hash);
7bd9bcf3
MH
985 return 0;
986 }
987
2f40e954
NTND
988 if (refs_read_ref_full(ref_store, refname,
989 RESOLVE_REF_READING, base, &flag))
7bd9bcf3
MH
990 return -1;
991
992 /*
993 * If the reference is packed, read its ref_entry from the
994 * cache in the hope that we already know its peeled value.
995 * We only try this optimization on packed references because
996 * (a) forcing the filling of the loose reference cache could
997 * be expensive and (b) loose references anyway usually do not
998 * have REF_KNOWS_PEELED.
999 */
1000 if (flag & REF_ISPACKED) {
f0d21efc 1001 struct ref_entry *r = get_packed_ref(refs, refname);
7bd9bcf3
MH
1002 if (r) {
1003 if (peel_entry(r, 0))
1004 return -1;
1005 hashcpy(sha1, r->u.value.peeled.hash);
1006 return 0;
1007 }
1008 }
1009
1010 return peel_object(base, sha1);
1011}
1012
3bc581b9
MH
1013struct files_ref_iterator {
1014 struct ref_iterator base;
1015
7bd9bcf3 1016 struct packed_ref_cache *packed_ref_cache;
3bc581b9
MH
1017 struct ref_iterator *iter0;
1018 unsigned int flags;
1019};
7bd9bcf3 1020
3bc581b9
MH
1021static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
1022{
1023 struct files_ref_iterator *iter =
1024 (struct files_ref_iterator *)ref_iterator;
1025 int ok;
7bd9bcf3 1026
3bc581b9 1027 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
0c09ec07
DT
1028 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
1029 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
1030 continue;
1031
3bc581b9
MH
1032 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
1033 !ref_resolves_to_object(iter->iter0->refname,
1034 iter->iter0->oid,
1035 iter->iter0->flags))
1036 continue;
1037
1038 iter->base.refname = iter->iter0->refname;
1039 iter->base.oid = iter->iter0->oid;
1040 iter->base.flags = iter->iter0->flags;
1041 return ITER_OK;
7bd9bcf3
MH
1042 }
1043
3bc581b9
MH
1044 iter->iter0 = NULL;
1045 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
1046 ok = ITER_ERROR;
1047
1048 return ok;
7bd9bcf3
MH
1049}
1050
3bc581b9
MH
1051static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
1052 struct object_id *peeled)
7bd9bcf3 1053{
3bc581b9
MH
1054 struct files_ref_iterator *iter =
1055 (struct files_ref_iterator *)ref_iterator;
93770590 1056
3bc581b9
MH
1057 return ref_iterator_peel(iter->iter0, peeled);
1058}
1059
1060static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
1061{
1062 struct files_ref_iterator *iter =
1063 (struct files_ref_iterator *)ref_iterator;
1064 int ok = ITER_DONE;
1065
1066 if (iter->iter0)
1067 ok = ref_iterator_abort(iter->iter0);
1068
1069 release_packed_ref_cache(iter->packed_ref_cache);
1070 base_ref_iterator_free(ref_iterator);
1071 return ok;
1072}
1073
1074static struct ref_iterator_vtable files_ref_iterator_vtable = {
1075 files_ref_iterator_advance,
1076 files_ref_iterator_peel,
1077 files_ref_iterator_abort
1078};
1079
1a769003 1080static struct ref_iterator *files_ref_iterator_begin(
37b6f6d5 1081 struct ref_store *ref_store,
3bc581b9
MH
1082 const char *prefix, unsigned int flags)
1083{
9e7ec634 1084 struct files_ref_store *refs;
3bc581b9
MH
1085 struct ref_dir *loose_dir, *packed_dir;
1086 struct ref_iterator *loose_iter, *packed_iter;
1087 struct files_ref_iterator *iter;
1088 struct ref_iterator *ref_iterator;
1089
7bd9bcf3
MH
1090 if (ref_paranoia < 0)
1091 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1092 if (ref_paranoia)
3bc581b9
MH
1093 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1094
9e7ec634
NTND
1095 refs = files_downcast(ref_store,
1096 REF_STORE_READ | (ref_paranoia ? 0 : REF_STORE_ODB),
1097 "ref_iterator_begin");
1098
3bc581b9
MH
1099 iter = xcalloc(1, sizeof(*iter));
1100 ref_iterator = &iter->base;
1101 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
1102
1103 /*
1104 * We must make sure that all loose refs are read before
1105 * accessing the packed-refs file; this avoids a race
1106 * condition if loose refs are migrated to the packed-refs
1107 * file by a simultaneous process, but our in-memory view is
1108 * from before the migration. We ensure this as follows:
1109 * First, we call prime_ref_dir(), which pre-reads the loose
1110 * references for the subtree into the cache. (If they've
1111 * already been read, that's OK; we only need to guarantee
1112 * that they're read before the packed refs, not *how much*
1113 * before.) After that, we call get_packed_ref_cache(), which
1114 * internally checks whether the packed-ref cache is up to
1115 * date with what is on disk, and re-reads it if not.
1116 */
1117
86f42358 1118 loose_dir = get_loose_ref_dir(refs);
3bc581b9
MH
1119
1120 if (prefix && *prefix)
1121 loose_dir = find_containing_dir(loose_dir, prefix, 0);
7bd9bcf3 1122
3bc581b9
MH
1123 if (loose_dir) {
1124 prime_ref_dir(loose_dir);
1125 loose_iter = cache_ref_iterator_begin(loose_dir);
1126 } else {
1127 /* There's nothing to iterate over. */
1128 loose_iter = empty_ref_iterator_begin();
1129 }
1130
1131 iter->packed_ref_cache = get_packed_ref_cache(refs);
1132 acquire_packed_ref_cache(iter->packed_ref_cache);
1133 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);
1134
1135 if (prefix && *prefix)
1136 packed_dir = find_containing_dir(packed_dir, prefix, 0);
1137
1138 if (packed_dir) {
1139 packed_iter = cache_ref_iterator_begin(packed_dir);
1140 } else {
1141 /* There's nothing to iterate over. */
1142 packed_iter = empty_ref_iterator_begin();
1143 }
1144
1145 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
1146 iter->flags = flags;
1147
1148 return ref_iterator;
7bd9bcf3
MH
1149}
1150
7bd9bcf3
MH
1151/*
1152 * Verify that the reference locked by lock has the value old_sha1.
1153 * Fail if the reference doesn't exist and mustexist is set. Return 0
1154 * on success. On error, write an error message to err, set errno, and
1155 * return a negative value.
1156 */
2f40e954 1157static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
7bd9bcf3
MH
1158 const unsigned char *old_sha1, int mustexist,
1159 struct strbuf *err)
1160{
1161 assert(err);
1162
2f40e954
NTND
1163 if (refs_read_ref_full(ref_store, lock->ref_name,
1164 mustexist ? RESOLVE_REF_READING : 0,
1165 lock->old_oid.hash, NULL)) {
6294dcb4
JK
1166 if (old_sha1) {
1167 int save_errno = errno;
0568c8e9 1168 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
6294dcb4
JK
1169 errno = save_errno;
1170 return -1;
1171 } else {
c368dde9 1172 oidclr(&lock->old_oid);
6294dcb4
JK
1173 return 0;
1174 }
7bd9bcf3 1175 }
6294dcb4 1176 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
0568c8e9 1177 strbuf_addf(err, "ref '%s' is at %s but expected %s",
7bd9bcf3 1178 lock->ref_name,
c368dde9 1179 oid_to_hex(&lock->old_oid),
7bd9bcf3
MH
1180 sha1_to_hex(old_sha1));
1181 errno = EBUSY;
1182 return -1;
1183 }
1184 return 0;
1185}
1186
1187static int remove_empty_directories(struct strbuf *path)
1188{
1189 /*
1190 * we want to create a file but there is a directory there;
1191 * if that is an empty directory (or a directory that contains
1192 * only empty directories), remove them.
1193 */
1194 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
1195}
1196
3b5d3c98
MH
1197static int create_reflock(const char *path, void *cb)
1198{
1199 struct lock_file *lk = cb;
1200
1201 return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;
1202}
1203
7bd9bcf3
MH
1204/*
1205 * Locks a ref returning the lock on success and NULL on failure.
1206 * On failure errno is set to something meaningful.
1207 */
7eb27cdf
MH
1208static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
1209 const char *refname,
7bd9bcf3
MH
1210 const unsigned char *old_sha1,
1211 const struct string_list *extras,
1212 const struct string_list *skip,
bcb497d0 1213 unsigned int flags, int *type,
7bd9bcf3
MH
1214 struct strbuf *err)
1215{
1216 struct strbuf ref_file = STRBUF_INIT;
7bd9bcf3
MH
1217 struct ref_lock *lock;
1218 int last_errno = 0;
7bd9bcf3 1219 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
7a418f3a 1220 int resolve_flags = RESOLVE_REF_NO_RECURSE;
7a418f3a 1221 int resolved;
7bd9bcf3 1222
32c597e7 1223 files_assert_main_repository(refs, "lock_ref_sha1_basic");
7bd9bcf3
MH
1224 assert(err);
1225
1226 lock = xcalloc(1, sizeof(struct ref_lock));
1227
1228 if (mustexist)
1229 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 1230 if (flags & REF_DELETING)
7bd9bcf3 1231 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
7bd9bcf3 1232
19e02f4f 1233 files_ref_path(refs, &ref_file, refname);
2f40e954
NTND
1234 resolved = !!refs_resolve_ref_unsafe(&refs->base,
1235 refname, resolve_flags,
1236 lock->old_oid.hash, type);
7a418f3a 1237 if (!resolved && errno == EISDIR) {
7bd9bcf3
MH
1238 /*
1239 * we are trying to lock foo but we used to
1240 * have foo/bar which now does not exist;
1241 * it is normal for the empty directory 'foo'
1242 * to remain.
1243 */
7a418f3a 1244 if (remove_empty_directories(&ref_file)) {
7bd9bcf3 1245 last_errno = errno;
b05855b5
MH
1246 if (!refs_verify_refname_available(
1247 &refs->base,
1248 refname, extras, skip, err))
7bd9bcf3 1249 strbuf_addf(err, "there are still refs under '%s'",
7a418f3a 1250 refname);
7bd9bcf3
MH
1251 goto error_return;
1252 }
2f40e954
NTND
1253 resolved = !!refs_resolve_ref_unsafe(&refs->base,
1254 refname, resolve_flags,
1255 lock->old_oid.hash, type);
7bd9bcf3 1256 }
7a418f3a 1257 if (!resolved) {
7bd9bcf3
MH
1258 last_errno = errno;
1259 if (last_errno != ENOTDIR ||
b05855b5
MH
1260 !refs_verify_refname_available(&refs->base, refname,
1261 extras, skip, err))
0568c8e9 1262 strbuf_addf(err, "unable to resolve reference '%s': %s",
7a418f3a 1263 refname, strerror(last_errno));
7bd9bcf3
MH
1264
1265 goto error_return;
1266 }
2859dcd4 1267
7bd9bcf3
MH
1268 /*
1269 * If the ref did not exist and we are creating it, make sure
1270 * there is no existing packed ref whose name begins with our
1271 * refname, nor a packed ref whose name is a proper prefix of
1272 * our refname.
1273 */
1274 if (is_null_oid(&lock->old_oid) &&
524a9fdb
MH
1275 refs_verify_refname_available(&refs->base, refname,
1276 extras, skip, err)) {
7bd9bcf3
MH
1277 last_errno = ENOTDIR;
1278 goto error_return;
1279 }
1280
1281 lock->lk = xcalloc(1, sizeof(struct lock_file));
1282
7bd9bcf3 1283 lock->ref_name = xstrdup(refname);
7bd9bcf3 1284
3b5d3c98 1285 if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
7bd9bcf3 1286 last_errno = errno;
3b5d3c98 1287 unable_to_lock_message(ref_file.buf, errno, err);
7bd9bcf3
MH
1288 goto error_return;
1289 }
1290
2f40e954 1291 if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) {
7bd9bcf3
MH
1292 last_errno = errno;
1293 goto error_return;
1294 }
1295 goto out;
1296
1297 error_return:
1298 unlock_ref(lock);
1299 lock = NULL;
1300
1301 out:
1302 strbuf_release(&ref_file);
7bd9bcf3
MH
1303 errno = last_errno;
1304 return lock;
1305}
1306
1307/*
1308 * Write an entry to the packed-refs file for the specified refname.
1309 * If peeled is non-NULL, write it as the entry's peeled value.
1310 */
1311static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
1312 unsigned char *peeled)
1313{
1314 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
1315 if (peeled)
1316 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
1317}
1318
1319/*
1320 * An each_ref_entry_fn that writes the entry to a packed-refs file.
1321 */
1322static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
1323{
1324 enum peel_status peel_status = peel_entry(entry, 0);
1325
1326 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
1327 error("internal error: %s is not a valid packed reference!",
1328 entry->name);
1329 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
1330 peel_status == PEEL_PEELED ?
1331 entry->u.value.peeled.hash : NULL);
1332 return 0;
1333}
1334
1335/*
1336 * Lock the packed-refs file for writing. Flags is passed to
1337 * hold_lock_file_for_update(). Return 0 on success. On errors, set
1338 * errno appropriately and return a nonzero value.
1339 */
49c0df6a 1340static int lock_packed_refs(struct files_ref_store *refs, int flags)
7bd9bcf3
MH
1341{
1342 static int timeout_configured = 0;
1343 static int timeout_value = 1000;
7bd9bcf3
MH
1344 struct packed_ref_cache *packed_ref_cache;
1345
32c597e7 1346 files_assert_main_repository(refs, "lock_packed_refs");
49c0df6a 1347
7bd9bcf3
MH
1348 if (!timeout_configured) {
1349 git_config_get_int("core.packedrefstimeout", &timeout_value);
1350 timeout_configured = 1;
1351 }
1352
1353 if (hold_lock_file_for_update_timeout(
33dfb9f3 1354 &packlock, files_packed_refs_path(refs),
7bd9bcf3
MH
1355 flags, timeout_value) < 0)
1356 return -1;
1357 /*
1358 * Get the current packed-refs while holding the lock. If the
1359 * packed-refs file has been modified since we last read it,
1360 * this will automatically invalidate the cache and re-read
1361 * the packed-refs file.
1362 */
00eebe35 1363 packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
1364 packed_ref_cache->lock = &packlock;
1365 /* Increment the reference count to prevent it from being freed: */
1366 acquire_packed_ref_cache(packed_ref_cache);
1367 return 0;
1368}
1369
1370/*
1371 * Write the current version of the packed refs cache from memory to
1372 * disk. The packed-refs file must already be locked for writing (see
1373 * lock_packed_refs()). Return zero on success. On errors, set errno
1374 * and return a nonzero value
1375 */
49c0df6a 1376static int commit_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1377{
1378 struct packed_ref_cache *packed_ref_cache =
00eebe35 1379 get_packed_ref_cache(refs);
7bd9bcf3
MH
1380 int error = 0;
1381 int save_errno = 0;
1382 FILE *out;
1383
32c597e7 1384 files_assert_main_repository(refs, "commit_packed_refs");
49c0df6a 1385
7bd9bcf3
MH
1386 if (!packed_ref_cache->lock)
1387 die("internal error: packed-refs not locked");
1388
1389 out = fdopen_lock_file(packed_ref_cache->lock, "w");
1390 if (!out)
1391 die_errno("unable to fdopen packed-refs descriptor");
1392
1393 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
1394 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
5c7bba77 1395 write_packed_entry_fn, out);
7bd9bcf3
MH
1396
1397 if (commit_lock_file(packed_ref_cache->lock)) {
1398 save_errno = errno;
1399 error = -1;
1400 }
1401 packed_ref_cache->lock = NULL;
1402 release_packed_ref_cache(packed_ref_cache);
1403 errno = save_errno;
1404 return error;
1405}
1406
1407/*
1408 * Rollback the lockfile for the packed-refs file, and discard the
1409 * in-memory packed reference cache. (The packed-refs file will be
1410 * read anew if it is needed again after this function is called.)
1411 */
49c0df6a 1412static void rollback_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1413{
1414 struct packed_ref_cache *packed_ref_cache =
00eebe35 1415 get_packed_ref_cache(refs);
7bd9bcf3 1416
32c597e7 1417 files_assert_main_repository(refs, "rollback_packed_refs");
7bd9bcf3
MH
1418
1419 if (!packed_ref_cache->lock)
1420 die("internal error: packed-refs not locked");
1421 rollback_lock_file(packed_ref_cache->lock);
1422 packed_ref_cache->lock = NULL;
1423 release_packed_ref_cache(packed_ref_cache);
00eebe35 1424 clear_packed_ref_cache(refs);
7bd9bcf3
MH
1425}
1426
1427struct ref_to_prune {
1428 struct ref_to_prune *next;
1429 unsigned char sha1[20];
1430 char name[FLEX_ARRAY];
1431};
1432
1433struct pack_refs_cb_data {
1434 unsigned int flags;
1435 struct ref_dir *packed_refs;
1436 struct ref_to_prune *ref_to_prune;
1437};
1438
1439/*
1440 * An each_ref_entry_fn that is run over loose references only. If
1441 * the loose reference can be packed, add an entry in the packed ref
1442 * cache. If the reference should be pruned, also add it to
1443 * ref_to_prune in the pack_refs_cb_data.
1444 */
1445static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
1446{
1447 struct pack_refs_cb_data *cb = cb_data;
1448 enum peel_status peel_status;
1449 struct ref_entry *packed_entry;
1450 int is_tag_ref = starts_with(entry->name, "refs/tags/");
1451
1452 /* Do not pack per-worktree refs: */
1453 if (ref_type(entry->name) != REF_TYPE_NORMAL)
1454 return 0;
1455
1456 /* ALWAYS pack tags */
1457 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
1458 return 0;
1459
1460 /* Do not pack symbolic or broken refs: */
ffeef642 1461 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))
7bd9bcf3
MH
1462 return 0;
1463
1464 /* Add a packed ref cache entry equivalent to the loose entry. */
1465 peel_status = peel_entry(entry, 1);
1466 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
1467 die("internal error peeling reference %s (%s)",
1468 entry->name, oid_to_hex(&entry->u.value.oid));
bc1c696e 1469 packed_entry = find_ref_entry(cb->packed_refs, entry->name);
7bd9bcf3
MH
1470 if (packed_entry) {
1471 /* Overwrite existing packed entry with info from loose entry */
1472 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
1473 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
1474 } else {
1475 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
1476 REF_ISPACKED | REF_KNOWS_PEELED, 0);
a3ade2ba 1477 add_ref_entry(cb->packed_refs, packed_entry);
7bd9bcf3
MH
1478 }
1479 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
1480
1481 /* Schedule the loose reference for pruning if requested. */
1482 if ((cb->flags & PACK_REFS_PRUNE)) {
96ffc06f
JK
1483 struct ref_to_prune *n;
1484 FLEX_ALLOC_STR(n, name, entry->name);
7bd9bcf3 1485 hashcpy(n->sha1, entry->u.value.oid.hash);
7bd9bcf3
MH
1486 n->next = cb->ref_to_prune;
1487 cb->ref_to_prune = n;
1488 }
1489 return 0;
1490}
1491
a8f0db2d
MH
1492enum {
1493 REMOVE_EMPTY_PARENTS_REF = 0x01,
1494 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
1495};
1496
7bd9bcf3 1497/*
a8f0db2d
MH
1498 * Remove empty parent directories associated with the specified
1499 * reference and/or its reflog, but spare [logs/]refs/ and immediate
1500 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
1501 * REMOVE_EMPTY_PARENTS_REFLOG.
7bd9bcf3 1502 */
802de3da
NTND
1503static void try_remove_empty_parents(struct files_ref_store *refs,
1504 const char *refname,
1505 unsigned int flags)
7bd9bcf3 1506{
8bdaecb4 1507 struct strbuf buf = STRBUF_INIT;
e9dcc305 1508 struct strbuf sb = STRBUF_INIT;
7bd9bcf3
MH
1509 char *p, *q;
1510 int i;
8bdaecb4
MH
1511
1512 strbuf_addstr(&buf, refname);
1513 p = buf.buf;
7bd9bcf3
MH
1514 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
1515 while (*p && *p != '/')
1516 p++;
1517 /* tolerate duplicate slashes; see check_refname_format() */
1518 while (*p == '/')
1519 p++;
1520 }
8bdaecb4 1521 q = buf.buf + buf.len;
a8f0db2d 1522 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
7bd9bcf3
MH
1523 while (q > p && *q != '/')
1524 q--;
1525 while (q > p && *(q-1) == '/')
1526 q--;
1527 if (q == p)
1528 break;
8bdaecb4 1529 strbuf_setlen(&buf, q - buf.buf);
e9dcc305
NTND
1530
1531 strbuf_reset(&sb);
19e02f4f 1532 files_ref_path(refs, &sb, buf.buf);
e9dcc305 1533 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
a8f0db2d 1534 flags &= ~REMOVE_EMPTY_PARENTS_REF;
e9dcc305
NTND
1535
1536 strbuf_reset(&sb);
802de3da 1537 files_reflog_path(refs, &sb, buf.buf);
e9dcc305 1538 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
a8f0db2d 1539 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
7bd9bcf3 1540 }
8bdaecb4 1541 strbuf_release(&buf);
e9dcc305 1542 strbuf_release(&sb);
7bd9bcf3
MH
1543}
1544
1545/* make sure nobody touched the ref, and unlink */
2f40e954 1546static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
7bd9bcf3
MH
1547{
1548 struct ref_transaction *transaction;
1549 struct strbuf err = STRBUF_INIT;
1550
1551 if (check_refname_format(r->name, 0))
1552 return;
1553
2f40e954 1554 transaction = ref_store_transaction_begin(&refs->base, &err);
7bd9bcf3
MH
1555 if (!transaction ||
1556 ref_transaction_delete(transaction, r->name, r->sha1,
c52ce248 1557 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
7bd9bcf3
MH
1558 ref_transaction_commit(transaction, &err)) {
1559 ref_transaction_free(transaction);
1560 error("%s", err.buf);
1561 strbuf_release(&err);
1562 return;
1563 }
1564 ref_transaction_free(transaction);
1565 strbuf_release(&err);
7bd9bcf3
MH
1566}
1567
2f40e954 1568static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
7bd9bcf3
MH
1569{
1570 while (r) {
2f40e954 1571 prune_ref(refs, r);
7bd9bcf3
MH
1572 r = r->next;
1573 }
1574}
1575
8231527e 1576static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
7bd9bcf3 1577{
00eebe35 1578 struct files_ref_store *refs =
9e7ec634
NTND
1579 files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
1580 "pack_refs");
7bd9bcf3
MH
1581 struct pack_refs_cb_data cbdata;
1582
1583 memset(&cbdata, 0, sizeof(cbdata));
1584 cbdata.flags = flags;
1585
49c0df6a 1586 lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
00eebe35 1587 cbdata.packed_refs = get_packed_refs(refs);
7bd9bcf3 1588
86f42358 1589 do_for_each_entry_in_dir(get_loose_ref_dir(refs),
7bd9bcf3
MH
1590 pack_if_possible_fn, &cbdata);
1591
49c0df6a 1592 if (commit_packed_refs(refs))
7bd9bcf3
MH
1593 die_errno("unable to overwrite old ref-pack file");
1594
2f40e954 1595 prune_refs(refs, cbdata.ref_to_prune);
7bd9bcf3
MH
1596 return 0;
1597}
1598
1599/*
1600 * Rewrite the packed-refs file, omitting any refs listed in
1601 * 'refnames'. On error, leave packed-refs unchanged, write an error
1602 * message to 'err', and return a nonzero value.
1603 *
1604 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
1605 */
0a95ac5f
MH
1606static int repack_without_refs(struct files_ref_store *refs,
1607 struct string_list *refnames, struct strbuf *err)
7bd9bcf3
MH
1608{
1609 struct ref_dir *packed;
1610 struct string_list_item *refname;
1611 int ret, needs_repacking = 0, removed = 0;
1612
32c597e7 1613 files_assert_main_repository(refs, "repack_without_refs");
7bd9bcf3
MH
1614 assert(err);
1615
1616 /* Look for a packed ref */
1617 for_each_string_list_item(refname, refnames) {
f0d21efc 1618 if (get_packed_ref(refs, refname->string)) {
7bd9bcf3
MH
1619 needs_repacking = 1;
1620 break;
1621 }
1622 }
1623
1624 /* Avoid locking if we have nothing to do */
1625 if (!needs_repacking)
1626 return 0; /* no refname exists in packed refs */
1627
49c0df6a 1628 if (lock_packed_refs(refs, 0)) {
33dfb9f3 1629 unable_to_lock_message(files_packed_refs_path(refs), errno, err);
7bd9bcf3
MH
1630 return -1;
1631 }
00eebe35 1632 packed = get_packed_refs(refs);
7bd9bcf3
MH
1633
1634 /* Remove refnames from the cache */
1635 for_each_string_list_item(refname, refnames)
9fc3b063 1636 if (remove_entry_from_dir(packed, refname->string) != -1)
7bd9bcf3
MH
1637 removed = 1;
1638 if (!removed) {
1639 /*
1640 * All packed entries disappeared while we were
1641 * acquiring the lock.
1642 */
49c0df6a 1643 rollback_packed_refs(refs);
7bd9bcf3
MH
1644 return 0;
1645 }
1646
1647 /* Write what remains */
49c0df6a 1648 ret = commit_packed_refs(refs);
7bd9bcf3
MH
1649 if (ret)
1650 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
1651 strerror(errno));
1652 return ret;
1653}
1654
a27dcf89
DT
1655static int files_delete_refs(struct ref_store *ref_store,
1656 struct string_list *refnames, unsigned int flags)
7bd9bcf3 1657{
0a95ac5f 1658 struct files_ref_store *refs =
9e7ec634 1659 files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
7bd9bcf3
MH
1660 struct strbuf err = STRBUF_INIT;
1661 int i, result = 0;
1662
1663 if (!refnames->nr)
1664 return 0;
1665
0a95ac5f 1666 result = repack_without_refs(refs, refnames, &err);
7bd9bcf3
MH
1667 if (result) {
1668 /*
1669 * If we failed to rewrite the packed-refs file, then
1670 * it is unsafe to try to remove loose refs, because
1671 * doing so might expose an obsolete packed value for
1672 * a reference that might even point at an object that
1673 * has been garbage collected.
1674 */
1675 if (refnames->nr == 1)
1676 error(_("could not delete reference %s: %s"),
1677 refnames->items[0].string, err.buf);
1678 else
1679 error(_("could not delete references: %s"), err.buf);
1680
1681 goto out;
1682 }
1683
1684 for (i = 0; i < refnames->nr; i++) {
1685 const char *refname = refnames->items[i].string;
1686
2f40e954 1687 if (refs_delete_ref(&refs->base, NULL, refname, NULL, flags))
7bd9bcf3
MH
1688 result |= error(_("could not remove reference %s"), refname);
1689 }
1690
1691out:
1692 strbuf_release(&err);
1693 return result;
1694}
1695
1696/*
1697 * People using contrib's git-new-workdir have .git/logs/refs ->
1698 * /some/other/path/.git/logs/refs, and that may live on another device.
1699 *
1700 * IOW, to avoid cross device rename errors, the temporary renamed log must
1701 * live into logs/refs.
1702 */
a5c1efd6 1703#define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
7bd9bcf3 1704
e9dcc305
NTND
1705struct rename_cb {
1706 const char *tmp_renamed_log;
1707 int true_errno;
1708};
1709
1710static int rename_tmp_log_callback(const char *path, void *cb_data)
7bd9bcf3 1711{
e9dcc305 1712 struct rename_cb *cb = cb_data;
7bd9bcf3 1713
e9dcc305 1714 if (rename(cb->tmp_renamed_log, path)) {
6a7f3631
MH
1715 /*
1716 * rename(a, b) when b is an existing directory ought
1717 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
1718 * Sheesh. Record the true errno for error reporting,
1719 * but report EISDIR to raceproof_create_file() so
1720 * that it knows to retry.
1721 */
e9dcc305 1722 cb->true_errno = errno;
6a7f3631
MH
1723 if (errno == ENOTDIR)
1724 errno = EISDIR;
1725 return -1;
1726 } else {
1727 return 0;
7bd9bcf3 1728 }
6a7f3631 1729}
7bd9bcf3 1730
802de3da 1731static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
6a7f3631 1732{
e9dcc305
NTND
1733 struct strbuf path = STRBUF_INIT;
1734 struct strbuf tmp = STRBUF_INIT;
1735 struct rename_cb cb;
1736 int ret;
6a7f3631 1737
802de3da
NTND
1738 files_reflog_path(refs, &path, newrefname);
1739 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
e9dcc305
NTND
1740 cb.tmp_renamed_log = tmp.buf;
1741 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
6a7f3631
MH
1742 if (ret) {
1743 if (errno == EISDIR)
e9dcc305 1744 error("directory not empty: %s", path.buf);
6a7f3631 1745 else
990c98d2 1746 error("unable to move logfile %s to %s: %s",
e9dcc305
NTND
1747 tmp.buf, path.buf,
1748 strerror(cb.true_errno));
7bd9bcf3 1749 }
6a7f3631 1750
e9dcc305
NTND
1751 strbuf_release(&path);
1752 strbuf_release(&tmp);
7bd9bcf3
MH
1753 return ret;
1754}
1755
7bd9bcf3
MH
1756static int write_ref_to_lockfile(struct ref_lock *lock,
1757 const unsigned char *sha1, struct strbuf *err);
f18a7892
MH
1758static int commit_ref_update(struct files_ref_store *refs,
1759 struct ref_lock *lock,
7bd9bcf3 1760 const unsigned char *sha1, const char *logmsg,
5d9b2de4 1761 struct strbuf *err);
7bd9bcf3 1762
9b6b40d9
DT
1763static int files_rename_ref(struct ref_store *ref_store,
1764 const char *oldrefname, const char *newrefname,
1765 const char *logmsg)
7bd9bcf3 1766{
9b6b40d9 1767 struct files_ref_store *refs =
9e7ec634 1768 files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
7bd9bcf3
MH
1769 unsigned char sha1[20], orig_sha1[20];
1770 int flag = 0, logmoved = 0;
1771 struct ref_lock *lock;
1772 struct stat loginfo;
e9dcc305
NTND
1773 struct strbuf sb_oldref = STRBUF_INIT;
1774 struct strbuf sb_newref = STRBUF_INIT;
1775 struct strbuf tmp_renamed_log = STRBUF_INIT;
1776 int log, ret;
7bd9bcf3
MH
1777 struct strbuf err = STRBUF_INIT;
1778
802de3da
NTND
1779 files_reflog_path(refs, &sb_oldref, oldrefname);
1780 files_reflog_path(refs, &sb_newref, newrefname);
1781 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
e9dcc305
NTND
1782
1783 log = !lstat(sb_oldref.buf, &loginfo);
0a3f07d6
NTND
1784 if (log && S_ISLNK(loginfo.st_mode)) {
1785 ret = error("reflog for %s is a symlink", oldrefname);
1786 goto out;
1787 }
7bd9bcf3 1788
2f40e954
NTND
1789 if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
1790 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
0a3f07d6
NTND
1791 orig_sha1, &flag)) {
1792 ret = error("refname %s not found", oldrefname);
1793 goto out;
1794 }
e711b1af 1795
0a3f07d6
NTND
1796 if (flag & REF_ISSYMREF) {
1797 ret = error("refname %s is a symbolic ref, renaming it is not supported",
1798 oldrefname);
1799 goto out;
1800 }
7d2df051 1801 if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
0a3f07d6
NTND
1802 ret = 1;
1803 goto out;
1804 }
7bd9bcf3 1805
e9dcc305 1806 if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
a5c1efd6 1807 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
0a3f07d6
NTND
1808 oldrefname, strerror(errno));
1809 goto out;
1810 }
7bd9bcf3 1811
2f40e954
NTND
1812 if (refs_delete_ref(&refs->base, logmsg, oldrefname,
1813 orig_sha1, REF_NODEREF)) {
7bd9bcf3
MH
1814 error("unable to delete old %s", oldrefname);
1815 goto rollback;
1816 }
1817
12fd3496
DT
1818 /*
1819 * Since we are doing a shallow lookup, sha1 is not the
1820 * correct value to pass to delete_ref as old_sha1. But that
1821 * doesn't matter, because an old_sha1 check wouldn't add to
1822 * the safety anyway; we want to delete the reference whatever
1823 * its current value.
1824 */
2f40e954
NTND
1825 if (!refs_read_ref_full(&refs->base, newrefname,
1826 RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
1827 sha1, NULL) &&
1828 refs_delete_ref(&refs->base, NULL, newrefname,
1829 NULL, REF_NODEREF)) {
58364324 1830 if (errno == EISDIR) {
7bd9bcf3
MH
1831 struct strbuf path = STRBUF_INIT;
1832 int result;
1833
19e02f4f 1834 files_ref_path(refs, &path, newrefname);
7bd9bcf3
MH
1835 result = remove_empty_directories(&path);
1836 strbuf_release(&path);
1837
1838 if (result) {
1839 error("Directory not empty: %s", newrefname);
1840 goto rollback;
1841 }
1842 } else {
1843 error("unable to delete existing %s", newrefname);
1844 goto rollback;
1845 }
1846 }
1847
802de3da 1848 if (log && rename_tmp_log(refs, newrefname))
7bd9bcf3
MH
1849 goto rollback;
1850
1851 logmoved = log;
1852
7eb27cdf
MH
1853 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
1854 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
1855 if (!lock) {
1856 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
1857 strbuf_release(&err);
1858 goto rollback;
1859 }
1860 hashcpy(lock->old_oid.hash, orig_sha1);
1861
1862 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 1863 commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {
7bd9bcf3
MH
1864 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
1865 strbuf_release(&err);
1866 goto rollback;
1867 }
1868
0a3f07d6
NTND
1869 ret = 0;
1870 goto out;
7bd9bcf3
MH
1871
1872 rollback:
7eb27cdf
MH
1873 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
1874 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
1875 if (!lock) {
1876 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
1877 strbuf_release(&err);
1878 goto rollbacklog;
1879 }
1880
1881 flag = log_all_ref_updates;
341fb286 1882 log_all_ref_updates = LOG_REFS_NONE;
7bd9bcf3 1883 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 1884 commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {
7bd9bcf3
MH
1885 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
1886 strbuf_release(&err);
1887 }
1888 log_all_ref_updates = flag;
1889
1890 rollbacklog:
e9dcc305 1891 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
7bd9bcf3
MH
1892 error("unable to restore logfile %s from %s: %s",
1893 oldrefname, newrefname, strerror(errno));
1894 if (!logmoved && log &&
e9dcc305 1895 rename(tmp_renamed_log.buf, sb_oldref.buf))
a5c1efd6 1896 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
7bd9bcf3 1897 oldrefname, strerror(errno));
0a3f07d6
NTND
1898 ret = 1;
1899 out:
e9dcc305
NTND
1900 strbuf_release(&sb_newref);
1901 strbuf_release(&sb_oldref);
1902 strbuf_release(&tmp_renamed_log);
1903
0a3f07d6 1904 return ret;
7bd9bcf3
MH
1905}
1906
1907static int close_ref(struct ref_lock *lock)
1908{
1909 if (close_lock_file(lock->lk))
1910 return -1;
1911 return 0;
1912}
1913
1914static int commit_ref(struct ref_lock *lock)
1915{
5387c0d8
MH
1916 char *path = get_locked_file_path(lock->lk);
1917 struct stat st;
1918
1919 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
1920 /*
1921 * There is a directory at the path we want to rename
1922 * the lockfile to. Hopefully it is empty; try to
1923 * delete it.
1924 */
1925 size_t len = strlen(path);
1926 struct strbuf sb_path = STRBUF_INIT;
1927
1928 strbuf_attach(&sb_path, path, len, len);
1929
1930 /*
1931 * If this fails, commit_lock_file() will also fail
1932 * and will report the problem.
1933 */
1934 remove_empty_directories(&sb_path);
1935 strbuf_release(&sb_path);
1936 } else {
1937 free(path);
1938 }
1939
7bd9bcf3
MH
1940 if (commit_lock_file(lock->lk))
1941 return -1;
1942 return 0;
1943}
1944
1fb0c809
MH
1945static int open_or_create_logfile(const char *path, void *cb)
1946{
1947 int *fd = cb;
1948
1949 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
1950 return (*fd < 0) ? -1 : 0;
1951}
1952
7bd9bcf3 1953/*
4533e534
MH
1954 * Create a reflog for a ref. If force_create = 0, only create the
1955 * reflog for certain refs (those for which should_autocreate_reflog
1956 * returns non-zero). Otherwise, create it regardless of the reference
1957 * name. If the logfile already existed or was created, return 0 and
1958 * set *logfd to the file descriptor opened for appending to the file.
1959 * If no logfile exists and we decided not to create one, return 0 and
1960 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
1961 * return -1.
7bd9bcf3 1962 */
802de3da
NTND
1963static int log_ref_setup(struct files_ref_store *refs,
1964 const char *refname, int force_create,
4533e534 1965 int *logfd, struct strbuf *err)
7bd9bcf3 1966{
802de3da
NTND
1967 struct strbuf logfile_sb = STRBUF_INIT;
1968 char *logfile;
1969
1970 files_reflog_path(refs, &logfile_sb, refname);
1971 logfile = strbuf_detach(&logfile_sb, NULL);
7bd9bcf3 1972
7bd9bcf3 1973 if (force_create || should_autocreate_reflog(refname)) {
4533e534 1974 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1fb0c809
MH
1975 if (errno == ENOENT)
1976 strbuf_addf(err, "unable to create directory for '%s': "
4533e534 1977 "%s", logfile, strerror(errno));
1fb0c809
MH
1978 else if (errno == EISDIR)
1979 strbuf_addf(err, "there are still logs under '%s'",
4533e534 1980 logfile);
1fb0c809 1981 else
854bda6b 1982 strbuf_addf(err, "unable to append to '%s': %s",
4533e534 1983 logfile, strerror(errno));
7bd9bcf3 1984
4533e534 1985 goto error;
7bd9bcf3 1986 }
854bda6b 1987 } else {
4533e534 1988 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
e404f459 1989 if (*logfd < 0) {
854bda6b
MH
1990 if (errno == ENOENT || errno == EISDIR) {
1991 /*
1992 * The logfile doesn't already exist,
1993 * but that is not an error; it only
1994 * means that we won't write log
1995 * entries to it.
1996 */
1997 ;
1998 } else {
1999 strbuf_addf(err, "unable to append to '%s': %s",
4533e534
MH
2000 logfile, strerror(errno));
2001 goto error;
854bda6b 2002 }
7bd9bcf3
MH
2003 }
2004 }
2005
e404f459 2006 if (*logfd >= 0)
4533e534 2007 adjust_shared_perm(logfile);
854bda6b 2008
4533e534 2009 free(logfile);
7bd9bcf3 2010 return 0;
7bd9bcf3 2011
4533e534
MH
2012error:
2013 free(logfile);
2014 return -1;
7bd9bcf3 2015}
7bd9bcf3 2016
e3688bd6
DT
2017static int files_create_reflog(struct ref_store *ref_store,
2018 const char *refname, int force_create,
2019 struct strbuf *err)
7bd9bcf3 2020{
802de3da 2021 struct files_ref_store *refs =
9e7ec634 2022 files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
e404f459 2023 int fd;
7bd9bcf3 2024
802de3da 2025 if (log_ref_setup(refs, refname, force_create, &fd, err))
4533e534
MH
2026 return -1;
2027
e404f459
MH
2028 if (fd >= 0)
2029 close(fd);
4533e534
MH
2030
2031 return 0;
7bd9bcf3
MH
2032}
2033
2034static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2035 const unsigned char *new_sha1,
2036 const char *committer, const char *msg)
2037{
2038 int msglen, written;
2039 unsigned maxlen, len;
2040 char *logrec;
2041
2042 msglen = msg ? strlen(msg) : 0;
2043 maxlen = strlen(committer) + msglen + 100;
2044 logrec = xmalloc(maxlen);
2045 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2046 sha1_to_hex(old_sha1),
2047 sha1_to_hex(new_sha1),
2048 committer);
2049 if (msglen)
2050 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2051
2052 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2053 free(logrec);
2054 if (written != len)
2055 return -1;
2056
2057 return 0;
2058}
2059
802de3da
NTND
2060static int files_log_ref_write(struct files_ref_store *refs,
2061 const char *refname, const unsigned char *old_sha1,
11f8457f
NTND
2062 const unsigned char *new_sha1, const char *msg,
2063 int flags, struct strbuf *err)
7bd9bcf3 2064{
e404f459 2065 int logfd, result;
7bd9bcf3 2066
341fb286
CW
2067 if (log_all_ref_updates == LOG_REFS_UNSET)
2068 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
7bd9bcf3 2069
802de3da
NTND
2070 result = log_ref_setup(refs, refname,
2071 flags & REF_FORCE_CREATE_REFLOG,
4533e534 2072 &logfd, err);
7bd9bcf3
MH
2073
2074 if (result)
2075 return result;
2076
7bd9bcf3
MH
2077 if (logfd < 0)
2078 return 0;
2079 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2080 git_committer_info(0), msg);
2081 if (result) {
e9dcc305 2082 struct strbuf sb = STRBUF_INIT;
87b21e05
MH
2083 int save_errno = errno;
2084
802de3da 2085 files_reflog_path(refs, &sb, refname);
87b21e05 2086 strbuf_addf(err, "unable to append to '%s': %s",
e9dcc305
NTND
2087 sb.buf, strerror(save_errno));
2088 strbuf_release(&sb);
7bd9bcf3
MH
2089 close(logfd);
2090 return -1;
2091 }
2092 if (close(logfd)) {
e9dcc305 2093 struct strbuf sb = STRBUF_INIT;
87b21e05
MH
2094 int save_errno = errno;
2095
802de3da 2096 files_reflog_path(refs, &sb, refname);
87b21e05 2097 strbuf_addf(err, "unable to append to '%s': %s",
e9dcc305
NTND
2098 sb.buf, strerror(save_errno));
2099 strbuf_release(&sb);
7bd9bcf3
MH
2100 return -1;
2101 }
2102 return 0;
2103}
2104
7bd9bcf3
MH
2105/*
2106 * Write sha1 into the open lockfile, then close the lockfile. On
2107 * errors, rollback the lockfile, fill in *err and
2108 * return -1.
2109 */
2110static int write_ref_to_lockfile(struct ref_lock *lock,
2111 const unsigned char *sha1, struct strbuf *err)
2112{
2113 static char term = '\n';
2114 struct object *o;
2115 int fd;
2116
2117 o = parse_object(sha1);
2118 if (!o) {
2119 strbuf_addf(err,
0568c8e9 2120 "trying to write ref '%s' with nonexistent object %s",
7bd9bcf3
MH
2121 lock->ref_name, sha1_to_hex(sha1));
2122 unlock_ref(lock);
2123 return -1;
2124 }
2125 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2126 strbuf_addf(err,
0568c8e9 2127 "trying to write non-commit object %s to branch '%s'",
7bd9bcf3
MH
2128 sha1_to_hex(sha1), lock->ref_name);
2129 unlock_ref(lock);
2130 return -1;
2131 }
2132 fd = get_lock_file_fd(lock->lk);
2133 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
2134 write_in_full(fd, &term, 1) != 1 ||
2135 close_ref(lock) < 0) {
2136 strbuf_addf(err,
0568c8e9 2137 "couldn't write '%s'", get_lock_file_path(lock->lk));
7bd9bcf3
MH
2138 unlock_ref(lock);
2139 return -1;
2140 }
2141 return 0;
2142}
2143
2144/*
2145 * Commit a change to a loose reference that has already been written
2146 * to the loose reference lockfile. Also update the reflogs if
2147 * necessary, using the specified lockmsg (which can be NULL).
2148 */
f18a7892
MH
2149static int commit_ref_update(struct files_ref_store *refs,
2150 struct ref_lock *lock,
7bd9bcf3 2151 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2152 struct strbuf *err)
7bd9bcf3 2153{
32c597e7 2154 files_assert_main_repository(refs, "commit_ref_update");
00eebe35
MH
2155
2156 clear_loose_ref_cache(refs);
802de3da
NTND
2157 if (files_log_ref_write(refs, lock->ref_name,
2158 lock->old_oid.hash, sha1,
81b1b6d4 2159 logmsg, 0, err)) {
7bd9bcf3 2160 char *old_msg = strbuf_detach(err, NULL);
0568c8e9 2161 strbuf_addf(err, "cannot update the ref '%s': %s",
7bd9bcf3
MH
2162 lock->ref_name, old_msg);
2163 free(old_msg);
2164 unlock_ref(lock);
2165 return -1;
2166 }
7a418f3a
MH
2167
2168 if (strcmp(lock->ref_name, "HEAD") != 0) {
7bd9bcf3
MH
2169 /*
2170 * Special hack: If a branch is updated directly and HEAD
2171 * points to it (may happen on the remote side of a push
2172 * for example) then logically the HEAD reflog should be
2173 * updated too.
2174 * A generic solution implies reverse symref information,
2175 * but finding all symrefs pointing to the given branch
2176 * would be rather costly for this rare event (the direct
2177 * update of a branch) to be worth it. So let's cheat and
2178 * check with HEAD only which should cover 99% of all usage
2179 * scenarios (even 100% of the default ones).
2180 */
2181 unsigned char head_sha1[20];
2182 int head_flag;
2183 const char *head_ref;
7a418f3a 2184
2f40e954
NTND
2185 head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
2186 RESOLVE_REF_READING,
2187 head_sha1, &head_flag);
7bd9bcf3
MH
2188 if (head_ref && (head_flag & REF_ISSYMREF) &&
2189 !strcmp(head_ref, lock->ref_name)) {
2190 struct strbuf log_err = STRBUF_INIT;
802de3da
NTND
2191 if (files_log_ref_write(refs, "HEAD",
2192 lock->old_oid.hash, sha1,
2193 logmsg, 0, &log_err)) {
7bd9bcf3
MH
2194 error("%s", log_err.buf);
2195 strbuf_release(&log_err);
2196 }
2197 }
2198 }
7a418f3a 2199
7bd9bcf3 2200 if (commit_ref(lock)) {
0568c8e9 2201 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
7bd9bcf3
MH
2202 unlock_ref(lock);
2203 return -1;
2204 }
2205
2206 unlock_ref(lock);
2207 return 0;
2208}
2209
370e5ad6 2210static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 2211{
370e5ad6 2212 int ret = -1;
7bd9bcf3 2213#ifndef NO_SYMLINK_HEAD
370e5ad6
JK
2214 char *ref_path = get_locked_file_path(lock->lk);
2215 unlink(ref_path);
2216 ret = symlink(target, ref_path);
2217 free(ref_path);
2218
2219 if (ret)
7bd9bcf3 2220 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 2221#endif
370e5ad6
JK
2222 return ret;
2223}
7bd9bcf3 2224
802de3da
NTND
2225static void update_symref_reflog(struct files_ref_store *refs,
2226 struct ref_lock *lock, const char *refname,
370e5ad6
JK
2227 const char *target, const char *logmsg)
2228{
2229 struct strbuf err = STRBUF_INIT;
2230 unsigned char new_sha1[20];
2f40e954
NTND
2231 if (logmsg &&
2232 !refs_read_ref_full(&refs->base, target,
2233 RESOLVE_REF_READING, new_sha1, NULL) &&
802de3da
NTND
2234 files_log_ref_write(refs, refname, lock->old_oid.hash,
2235 new_sha1, logmsg, 0, &err)) {
7bd9bcf3
MH
2236 error("%s", err.buf);
2237 strbuf_release(&err);
2238 }
370e5ad6 2239}
7bd9bcf3 2240
802de3da
NTND
2241static int create_symref_locked(struct files_ref_store *refs,
2242 struct ref_lock *lock, const char *refname,
370e5ad6
JK
2243 const char *target, const char *logmsg)
2244{
2245 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
802de3da 2246 update_symref_reflog(refs, lock, refname, target, logmsg);
370e5ad6
JK
2247 return 0;
2248 }
2249
2250 if (!fdopen_lock_file(lock->lk, "w"))
2251 return error("unable to fdopen %s: %s",
2252 lock->lk->tempfile.filename.buf, strerror(errno));
2253
802de3da 2254 update_symref_reflog(refs, lock, refname, target, logmsg);
396da8f7 2255
370e5ad6
JK
2256 /* no error check; commit_ref will check ferror */
2257 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
2258 if (commit_ref(lock) < 0)
2259 return error("unable to write symref for %s: %s", refname,
2260 strerror(errno));
7bd9bcf3
MH
2261 return 0;
2262}
2263
284689ba
MH
2264static int files_create_symref(struct ref_store *ref_store,
2265 const char *refname, const char *target,
2266 const char *logmsg)
370e5ad6 2267{
7eb27cdf 2268 struct files_ref_store *refs =
9e7ec634 2269 files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
370e5ad6
JK
2270 struct strbuf err = STRBUF_INIT;
2271 struct ref_lock *lock;
2272 int ret;
2273
7eb27cdf
MH
2274 lock = lock_ref_sha1_basic(refs, refname, NULL,
2275 NULL, NULL, REF_NODEREF, NULL,
370e5ad6
JK
2276 &err);
2277 if (!lock) {
2278 error("%s", err.buf);
2279 strbuf_release(&err);
2280 return -1;
2281 }
2282
802de3da 2283 ret = create_symref_locked(refs, lock, refname, target, logmsg);
370e5ad6
JK
2284 unlock_ref(lock);
2285 return ret;
2286}
2287
39ee4c6c 2288int set_worktree_head_symref(const char *gitdir, const char *target, const char *logmsg)
2233066e 2289{
802de3da
NTND
2290 /*
2291 * FIXME: this obviously will not work well for future refs
2292 * backends. This function needs to die.
2293 */
2294 struct files_ref_store *refs =
9e7ec634
NTND
2295 files_downcast(get_main_ref_store(),
2296 REF_STORE_WRITE,
2297 "set_head_symref");
802de3da 2298
2233066e
KY
2299 static struct lock_file head_lock;
2300 struct ref_lock *lock;
2233066e
KY
2301 struct strbuf head_path = STRBUF_INIT;
2302 const char *head_rel;
2303 int ret;
2304
2305 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));
2306 if (hold_lock_file_for_update(&head_lock, head_path.buf,
2307 LOCK_NO_DEREF) < 0) {
18eb3a9c
KY
2308 struct strbuf err = STRBUF_INIT;
2309 unable_to_lock_message(head_path.buf, errno, &err);
2233066e
KY
2310 error("%s", err.buf);
2311 strbuf_release(&err);
2312 strbuf_release(&head_path);
2313 return -1;
2314 }
2315
2316 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for
2317 linked trees */
2318 head_rel = remove_leading_path(head_path.buf,
2319 absolute_path(get_git_common_dir()));
2320 /* to make use of create_symref_locked(), initialize ref_lock */
2321 lock = xcalloc(1, sizeof(struct ref_lock));
2322 lock->lk = &head_lock;
2323 lock->ref_name = xstrdup(head_rel);
2233066e 2324
802de3da 2325 ret = create_symref_locked(refs, lock, head_rel, target, logmsg);
2233066e
KY
2326
2327 unlock_ref(lock); /* will free lock */
2328 strbuf_release(&head_path);
2329 return ret;
2330}
2331
e3688bd6
DT
2332static int files_reflog_exists(struct ref_store *ref_store,
2333 const char *refname)
7bd9bcf3 2334{
802de3da 2335 struct files_ref_store *refs =
9e7ec634 2336 files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
e9dcc305 2337 struct strbuf sb = STRBUF_INIT;
7bd9bcf3 2338 struct stat st;
e9dcc305 2339 int ret;
7bd9bcf3 2340
802de3da 2341 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
2342 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
2343 strbuf_release(&sb);
2344 return ret;
7bd9bcf3
MH
2345}
2346
e3688bd6
DT
2347static int files_delete_reflog(struct ref_store *ref_store,
2348 const char *refname)
7bd9bcf3 2349{
802de3da 2350 struct files_ref_store *refs =
9e7ec634 2351 files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
e9dcc305
NTND
2352 struct strbuf sb = STRBUF_INIT;
2353 int ret;
2354
802de3da 2355 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
2356 ret = remove_path(sb.buf);
2357 strbuf_release(&sb);
2358 return ret;
7bd9bcf3
MH
2359}
2360
2361static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
2362{
9461d272 2363 struct object_id ooid, noid;
7bd9bcf3
MH
2364 char *email_end, *message;
2365 unsigned long timestamp;
2366 int tz;
43bc3b6c 2367 const char *p = sb->buf;
7bd9bcf3
MH
2368
2369 /* old SP new SP name <email> SP time TAB msg LF */
43bc3b6c 2370 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
2371 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
2372 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
2373 !(email_end = strchr(p, '>')) ||
7bd9bcf3
MH
2374 email_end[1] != ' ' ||
2375 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
2376 !message || message[0] != ' ' ||
2377 (message[1] != '+' && message[1] != '-') ||
2378 !isdigit(message[2]) || !isdigit(message[3]) ||
2379 !isdigit(message[4]) || !isdigit(message[5]))
2380 return 0; /* corrupt? */
2381 email_end[1] = '\0';
2382 tz = strtol(message + 1, NULL, 10);
2383 if (message[6] != '\t')
2384 message += 6;
2385 else
2386 message += 7;
43bc3b6c 2387 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
7bd9bcf3
MH
2388}
2389
2390static char *find_beginning_of_line(char *bob, char *scan)
2391{
2392 while (bob < scan && *(--scan) != '\n')
2393 ; /* keep scanning backwards */
2394 /*
2395 * Return either beginning of the buffer, or LF at the end of
2396 * the previous line.
2397 */
2398 return scan;
2399}
2400
e3688bd6
DT
2401static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
2402 const char *refname,
2403 each_reflog_ent_fn fn,
2404 void *cb_data)
7bd9bcf3 2405{
802de3da 2406 struct files_ref_store *refs =
9e7ec634
NTND
2407 files_downcast(ref_store, REF_STORE_READ,
2408 "for_each_reflog_ent_reverse");
7bd9bcf3
MH
2409 struct strbuf sb = STRBUF_INIT;
2410 FILE *logfp;
2411 long pos;
2412 int ret = 0, at_tail = 1;
2413
802de3da 2414 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
2415 logfp = fopen(sb.buf, "r");
2416 strbuf_release(&sb);
7bd9bcf3
MH
2417 if (!logfp)
2418 return -1;
2419
2420 /* Jump to the end */
2421 if (fseek(logfp, 0, SEEK_END) < 0)
2422 return error("cannot seek back reflog for %s: %s",
2423 refname, strerror(errno));
2424 pos = ftell(logfp);
2425 while (!ret && 0 < pos) {
2426 int cnt;
2427 size_t nread;
2428 char buf[BUFSIZ];
2429 char *endp, *scanp;
2430
2431 /* Fill next block from the end */
2432 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
2433 if (fseek(logfp, pos - cnt, SEEK_SET))
2434 return error("cannot seek back reflog for %s: %s",
2435 refname, strerror(errno));
2436 nread = fread(buf, cnt, 1, logfp);
2437 if (nread != 1)
2438 return error("cannot read %d bytes from reflog for %s: %s",
2439 cnt, refname, strerror(errno));
2440 pos -= cnt;
2441
2442 scanp = endp = buf + cnt;
2443 if (at_tail && scanp[-1] == '\n')
2444 /* Looking at the final LF at the end of the file */
2445 scanp--;
2446 at_tail = 0;
2447
2448 while (buf < scanp) {
2449 /*
2450 * terminating LF of the previous line, or the beginning
2451 * of the buffer.
2452 */
2453 char *bp;
2454
2455 bp = find_beginning_of_line(buf, scanp);
2456
2457 if (*bp == '\n') {
2458 /*
2459 * The newline is the end of the previous line,
2460 * so we know we have complete line starting
2461 * at (bp + 1). Prefix it onto any prior data
2462 * we collected for the line and process it.
2463 */
2464 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
2465 scanp = bp;
2466 endp = bp + 1;
2467 ret = show_one_reflog_ent(&sb, fn, cb_data);
2468 strbuf_reset(&sb);
2469 if (ret)
2470 break;
2471 } else if (!pos) {
2472 /*
2473 * We are at the start of the buffer, and the
2474 * start of the file; there is no previous
2475 * line, and we have everything for this one.
2476 * Process it, and we can end the loop.
2477 */
2478 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2479 ret = show_one_reflog_ent(&sb, fn, cb_data);
2480 strbuf_reset(&sb);
2481 break;
2482 }
2483
2484 if (bp == buf) {
2485 /*
2486 * We are at the start of the buffer, and there
2487 * is more file to read backwards. Which means
2488 * we are in the middle of a line. Note that we
2489 * may get here even if *bp was a newline; that
2490 * just means we are at the exact end of the
2491 * previous line, rather than some spot in the
2492 * middle.
2493 *
2494 * Save away what we have to be combined with
2495 * the data from the next read.
2496 */
2497 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2498 break;
2499 }
2500 }
2501
2502 }
2503 if (!ret && sb.len)
2504 die("BUG: reverse reflog parser had leftover data");
2505
2506 fclose(logfp);
2507 strbuf_release(&sb);
2508 return ret;
2509}
2510
e3688bd6
DT
2511static int files_for_each_reflog_ent(struct ref_store *ref_store,
2512 const char *refname,
2513 each_reflog_ent_fn fn, void *cb_data)
7bd9bcf3 2514{
802de3da 2515 struct files_ref_store *refs =
9e7ec634
NTND
2516 files_downcast(ref_store, REF_STORE_READ,
2517 "for_each_reflog_ent");
7bd9bcf3
MH
2518 FILE *logfp;
2519 struct strbuf sb = STRBUF_INIT;
2520 int ret = 0;
2521
802de3da 2522 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
2523 logfp = fopen(sb.buf, "r");
2524 strbuf_release(&sb);
7bd9bcf3
MH
2525 if (!logfp)
2526 return -1;
2527
2528 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
2529 ret = show_one_reflog_ent(&sb, fn, cb_data);
2530 fclose(logfp);
2531 strbuf_release(&sb);
2532 return ret;
2533}
7bd9bcf3 2534
2880d16f
MH
2535struct files_reflog_iterator {
2536 struct ref_iterator base;
7bd9bcf3 2537
2f40e954 2538 struct ref_store *ref_store;
2880d16f
MH
2539 struct dir_iterator *dir_iterator;
2540 struct object_id oid;
2541};
7bd9bcf3 2542
2880d16f
MH
2543static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
2544{
2545 struct files_reflog_iterator *iter =
2546 (struct files_reflog_iterator *)ref_iterator;
2547 struct dir_iterator *diter = iter->dir_iterator;
2548 int ok;
2549
2550 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
2551 int flags;
2552
2553 if (!S_ISREG(diter->st.st_mode))
7bd9bcf3 2554 continue;
2880d16f
MH
2555 if (diter->basename[0] == '.')
2556 continue;
2557 if (ends_with(diter->basename, ".lock"))
7bd9bcf3 2558 continue;
7bd9bcf3 2559
2f40e954
NTND
2560 if (refs_read_ref_full(iter->ref_store,
2561 diter->relative_path, 0,
2562 iter->oid.hash, &flags)) {
2880d16f
MH
2563 error("bad ref for %s", diter->path.buf);
2564 continue;
7bd9bcf3 2565 }
2880d16f
MH
2566
2567 iter->base.refname = diter->relative_path;
2568 iter->base.oid = &iter->oid;
2569 iter->base.flags = flags;
2570 return ITER_OK;
7bd9bcf3 2571 }
2880d16f
MH
2572
2573 iter->dir_iterator = NULL;
2574 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
2575 ok = ITER_ERROR;
2576 return ok;
2577}
2578
2579static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
2580 struct object_id *peeled)
2581{
2582 die("BUG: ref_iterator_peel() called for reflog_iterator");
2583}
2584
2585static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
2586{
2587 struct files_reflog_iterator *iter =
2588 (struct files_reflog_iterator *)ref_iterator;
2589 int ok = ITER_DONE;
2590
2591 if (iter->dir_iterator)
2592 ok = dir_iterator_abort(iter->dir_iterator);
2593
2594 base_ref_iterator_free(ref_iterator);
2595 return ok;
2596}
2597
2598static struct ref_iterator_vtable files_reflog_iterator_vtable = {
2599 files_reflog_iterator_advance,
2600 files_reflog_iterator_peel,
2601 files_reflog_iterator_abort
2602};
2603
e3688bd6 2604static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2880d16f 2605{
802de3da 2606 struct files_ref_store *refs =
9e7ec634
NTND
2607 files_downcast(ref_store, REF_STORE_READ,
2608 "reflog_iterator_begin");
2880d16f
MH
2609 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
2610 struct ref_iterator *ref_iterator = &iter->base;
e9dcc305 2611 struct strbuf sb = STRBUF_INIT;
2880d16f
MH
2612
2613 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
802de3da 2614 files_reflog_path(refs, &sb, NULL);
e9dcc305 2615 iter->dir_iterator = dir_iterator_begin(sb.buf);
2f40e954 2616 iter->ref_store = ref_store;
e9dcc305 2617 strbuf_release(&sb);
2880d16f 2618 return ref_iterator;
7bd9bcf3
MH
2619}
2620
7bd9bcf3
MH
2621static int ref_update_reject_duplicates(struct string_list *refnames,
2622 struct strbuf *err)
2623{
2624 int i, n = refnames->nr;
2625
2626 assert(err);
2627
2628 for (i = 1; i < n; i++)
2629 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
2630 strbuf_addf(err,
0568c8e9 2631 "multiple updates for ref '%s' not allowed.",
7bd9bcf3
MH
2632 refnames->items[i].string);
2633 return 1;
2634 }
2635 return 0;
2636}
2637
165056b2 2638/*
92b1551b
MH
2639 * If update is a direct update of head_ref (the reference pointed to
2640 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
2641 */
2642static int split_head_update(struct ref_update *update,
2643 struct ref_transaction *transaction,
2644 const char *head_ref,
2645 struct string_list *affected_refnames,
2646 struct strbuf *err)
2647{
2648 struct string_list_item *item;
2649 struct ref_update *new_update;
2650
2651 if ((update->flags & REF_LOG_ONLY) ||
2652 (update->flags & REF_ISPRUNING) ||
2653 (update->flags & REF_UPDATE_VIA_HEAD))
2654 return 0;
2655
2656 if (strcmp(update->refname, head_ref))
2657 return 0;
2658
2659 /*
2660 * First make sure that HEAD is not already in the
2661 * transaction. This insertion is O(N) in the transaction
2662 * size, but it happens at most once per transaction.
2663 */
2664 item = string_list_insert(affected_refnames, "HEAD");
2665 if (item->util) {
2666 /* An entry already existed */
2667 strbuf_addf(err,
2668 "multiple updates for 'HEAD' (including one "
2669 "via its referent '%s') are not allowed",
2670 update->refname);
2671 return TRANSACTION_NAME_CONFLICT;
2672 }
2673
2674 new_update = ref_transaction_add_update(
2675 transaction, "HEAD",
2676 update->flags | REF_LOG_ONLY | REF_NODEREF,
2677 update->new_sha1, update->old_sha1,
2678 update->msg);
2679
2680 item->util = new_update;
2681
2682 return 0;
2683}
2684
2685/*
2686 * update is for a symref that points at referent and doesn't have
2687 * REF_NODEREF set. Split it into two updates:
2688 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
2689 * - A new, separate update for the referent reference
2690 * Note that the new update will itself be subject to splitting when
2691 * the iteration gets to it.
2692 */
fcc42ea0
MH
2693static int split_symref_update(struct files_ref_store *refs,
2694 struct ref_update *update,
92b1551b
MH
2695 const char *referent,
2696 struct ref_transaction *transaction,
2697 struct string_list *affected_refnames,
2698 struct strbuf *err)
2699{
2700 struct string_list_item *item;
2701 struct ref_update *new_update;
2702 unsigned int new_flags;
2703
2704 /*
2705 * First make sure that referent is not already in the
2706 * transaction. This insertion is O(N) in the transaction
2707 * size, but it happens at most once per symref in a
2708 * transaction.
2709 */
2710 item = string_list_insert(affected_refnames, referent);
2711 if (item->util) {
2712 /* An entry already existed */
2713 strbuf_addf(err,
2714 "multiple updates for '%s' (including one "
2715 "via symref '%s') are not allowed",
2716 referent, update->refname);
2717 return TRANSACTION_NAME_CONFLICT;
2718 }
2719
2720 new_flags = update->flags;
2721 if (!strcmp(update->refname, "HEAD")) {
2722 /*
2723 * Record that the new update came via HEAD, so that
2724 * when we process it, split_head_update() doesn't try
2725 * to add another reflog update for HEAD. Note that
2726 * this bit will be propagated if the new_update
2727 * itself needs to be split.
2728 */
2729 new_flags |= REF_UPDATE_VIA_HEAD;
2730 }
2731
2732 new_update = ref_transaction_add_update(
2733 transaction, referent, new_flags,
2734 update->new_sha1, update->old_sha1,
2735 update->msg);
2736
6e30b2f6
MH
2737 new_update->parent_update = update;
2738
2739 /*
2740 * Change the symbolic ref update to log only. Also, it
2741 * doesn't need to check its old SHA-1 value, as that will be
2742 * done when new_update is processed.
2743 */
92b1551b 2744 update->flags |= REF_LOG_ONLY | REF_NODEREF;
6e30b2f6 2745 update->flags &= ~REF_HAVE_OLD;
92b1551b
MH
2746
2747 item->util = new_update;
2748
2749 return 0;
2750}
2751
6e30b2f6
MH
2752/*
2753 * Return the refname under which update was originally requested.
2754 */
2755static const char *original_update_refname(struct ref_update *update)
2756{
2757 while (update->parent_update)
2758 update = update->parent_update;
2759
2760 return update->refname;
2761}
2762
e3f51039
MH
2763/*
2764 * Check whether the REF_HAVE_OLD and old_oid values stored in update
2765 * are consistent with oid, which is the reference's current value. If
2766 * everything is OK, return 0; otherwise, write an error message to
2767 * err and return -1.
2768 */
2769static int check_old_oid(struct ref_update *update, struct object_id *oid,
2770 struct strbuf *err)
2771{
2772 if (!(update->flags & REF_HAVE_OLD) ||
2773 !hashcmp(oid->hash, update->old_sha1))
2774 return 0;
2775
2776 if (is_null_sha1(update->old_sha1))
2777 strbuf_addf(err, "cannot lock ref '%s': "
2778 "reference already exists",
2779 original_update_refname(update));
2780 else if (is_null_oid(oid))
2781 strbuf_addf(err, "cannot lock ref '%s': "
2782 "reference is missing but expected %s",
2783 original_update_refname(update),
2784 sha1_to_hex(update->old_sha1));
2785 else
2786 strbuf_addf(err, "cannot lock ref '%s': "
2787 "is at %s but expected %s",
2788 original_update_refname(update),
2789 oid_to_hex(oid),
2790 sha1_to_hex(update->old_sha1));
2791
2792 return -1;
2793}
2794
92b1551b
MH
2795/*
2796 * Prepare for carrying out update:
2797 * - Lock the reference referred to by update.
2798 * - Read the reference under lock.
2799 * - Check that its old SHA-1 value (if specified) is correct, and in
2800 * any case record it in update->lock->old_oid for later use when
2801 * writing the reflog.
2802 * - If it is a symref update without REF_NODEREF, split it up into a
2803 * REF_LOG_ONLY update of the symref and add a separate update for
2804 * the referent to transaction.
2805 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
2806 * update of HEAD.
165056b2 2807 */
b3bbbc5c
MH
2808static int lock_ref_for_update(struct files_ref_store *refs,
2809 struct ref_update *update,
165056b2 2810 struct ref_transaction *transaction,
92b1551b 2811 const char *head_ref,
165056b2
MH
2812 struct string_list *affected_refnames,
2813 struct strbuf *err)
2814{
92b1551b
MH
2815 struct strbuf referent = STRBUF_INIT;
2816 int mustexist = (update->flags & REF_HAVE_OLD) &&
2817 !is_null_sha1(update->old_sha1);
165056b2 2818 int ret;
92b1551b 2819 struct ref_lock *lock;
165056b2 2820
32c597e7 2821 files_assert_main_repository(refs, "lock_ref_for_update");
b3bbbc5c 2822
92b1551b 2823 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
165056b2 2824 update->flags |= REF_DELETING;
92b1551b
MH
2825
2826 if (head_ref) {
2827 ret = split_head_update(update, transaction, head_ref,
2828 affected_refnames, err);
2829 if (ret)
2830 return ret;
2831 }
2832
f7b0a987 2833 ret = lock_raw_ref(refs, update->refname, mustexist,
92b1551b 2834 affected_refnames, NULL,
7d618264 2835 &lock, &referent,
92b1551b 2836 &update->type, err);
92b1551b 2837 if (ret) {
165056b2
MH
2838 char *reason;
2839
165056b2
MH
2840 reason = strbuf_detach(err, NULL);
2841 strbuf_addf(err, "cannot lock ref '%s': %s",
e3f51039 2842 original_update_refname(update), reason);
165056b2
MH
2843 free(reason);
2844 return ret;
2845 }
92b1551b 2846
7d618264 2847 update->backend_data = lock;
92b1551b 2848
8169d0d0 2849 if (update->type & REF_ISSYMREF) {
6e30b2f6
MH
2850 if (update->flags & REF_NODEREF) {
2851 /*
2852 * We won't be reading the referent as part of
2853 * the transaction, so we have to read it here
2854 * to record and possibly check old_sha1:
2855 */
2f40e954
NTND
2856 if (refs_read_ref_full(&refs->base,
2857 referent.buf, 0,
2858 lock->old_oid.hash, NULL)) {
6e30b2f6
MH
2859 if (update->flags & REF_HAVE_OLD) {
2860 strbuf_addf(err, "cannot lock ref '%s': "
e3f51039
MH
2861 "error reading reference",
2862 original_update_refname(update));
2863 return -1;
6e30b2f6 2864 }
e3f51039 2865 } else if (check_old_oid(update, &lock->old_oid, err)) {
8169d0d0 2866 return TRANSACTION_GENERIC_ERROR;
8169d0d0 2867 }
6e30b2f6
MH
2868 } else {
2869 /*
2870 * Create a new update for the reference this
2871 * symref is pointing at. Also, we will record
2872 * and verify old_sha1 for this update as part
2873 * of processing the split-off update, so we
2874 * don't have to do it here.
2875 */
fcc42ea0
MH
2876 ret = split_symref_update(refs, update,
2877 referent.buf, transaction,
92b1551b
MH
2878 affected_refnames, err);
2879 if (ret)
2880 return ret;
2881 }
6e30b2f6
MH
2882 } else {
2883 struct ref_update *parent_update;
8169d0d0 2884
e3f51039
MH
2885 if (check_old_oid(update, &lock->old_oid, err))
2886 return TRANSACTION_GENERIC_ERROR;
2887
6e30b2f6
MH
2888 /*
2889 * If this update is happening indirectly because of a
2890 * symref update, record the old SHA-1 in the parent
2891 * update:
2892 */
2893 for (parent_update = update->parent_update;
2894 parent_update;
2895 parent_update = parent_update->parent_update) {
7d618264
DT
2896 struct ref_lock *parent_lock = parent_update->backend_data;
2897 oidcpy(&parent_lock->old_oid, &lock->old_oid);
6e30b2f6 2898 }
92b1551b
MH
2899 }
2900
165056b2
MH
2901 if ((update->flags & REF_HAVE_NEW) &&
2902 !(update->flags & REF_DELETING) &&
2903 !(update->flags & REF_LOG_ONLY)) {
92b1551b
MH
2904 if (!(update->type & REF_ISSYMREF) &&
2905 !hashcmp(lock->old_oid.hash, update->new_sha1)) {
165056b2
MH
2906 /*
2907 * The reference already has the desired
2908 * value, so we don't need to write it.
2909 */
92b1551b 2910 } else if (write_ref_to_lockfile(lock, update->new_sha1,
165056b2
MH
2911 err)) {
2912 char *write_err = strbuf_detach(err, NULL);
2913
2914 /*
2915 * The lock was freed upon failure of
2916 * write_ref_to_lockfile():
2917 */
7d618264 2918 update->backend_data = NULL;
165056b2 2919 strbuf_addf(err,
e3f51039 2920 "cannot update ref '%s': %s",
165056b2
MH
2921 update->refname, write_err);
2922 free(write_err);
2923 return TRANSACTION_GENERIC_ERROR;
2924 } else {
2925 update->flags |= REF_NEEDS_COMMIT;
2926 }
2927 }
2928 if (!(update->flags & REF_NEEDS_COMMIT)) {
2929 /*
2930 * We didn't call write_ref_to_lockfile(), so
2931 * the lockfile is still open. Close it to
2932 * free up the file descriptor:
2933 */
92b1551b 2934 if (close_ref(lock)) {
165056b2
MH
2935 strbuf_addf(err, "couldn't close '%s.lock'",
2936 update->refname);
2937 return TRANSACTION_GENERIC_ERROR;
2938 }
2939 }
2940 return 0;
2941}
2942
127b42a1
RS
2943static int files_transaction_commit(struct ref_store *ref_store,
2944 struct ref_transaction *transaction,
2945 struct strbuf *err)
7bd9bcf3 2946{
00eebe35 2947 struct files_ref_store *refs =
9e7ec634
NTND
2948 files_downcast(ref_store, REF_STORE_WRITE,
2949 "ref_transaction_commit");
7bd9bcf3 2950 int ret = 0, i;
7bd9bcf3
MH
2951 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
2952 struct string_list_item *ref_to_delete;
2953 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
92b1551b
MH
2954 char *head_ref = NULL;
2955 int head_type;
2956 struct object_id head_oid;
e9dcc305 2957 struct strbuf sb = STRBUF_INIT;
7bd9bcf3
MH
2958
2959 assert(err);
2960
2961 if (transaction->state != REF_TRANSACTION_OPEN)
2962 die("BUG: commit called for transaction that is not open");
2963
efe47281 2964 if (!transaction->nr) {
7bd9bcf3
MH
2965 transaction->state = REF_TRANSACTION_CLOSED;
2966 return 0;
2967 }
2968
92b1551b
MH
2969 /*
2970 * Fail if a refname appears more than once in the
2971 * transaction. (If we end up splitting up any updates using
2972 * split_symref_update() or split_head_update(), those
2973 * functions will check that the new updates don't have the
2974 * same refname as any existing ones.)
2975 */
2976 for (i = 0; i < transaction->nr; i++) {
2977 struct ref_update *update = transaction->updates[i];
2978 struct string_list_item *item =
2979 string_list_append(&affected_refnames, update->refname);
2980
2981 /*
2982 * We store a pointer to update in item->util, but at
2983 * the moment we never use the value of this field
2984 * except to check whether it is non-NULL.
2985 */
2986 item->util = update;
2987 }
7bd9bcf3
MH
2988 string_list_sort(&affected_refnames);
2989 if (ref_update_reject_duplicates(&affected_refnames, err)) {
2990 ret = TRANSACTION_GENERIC_ERROR;
2991 goto cleanup;
2992 }
2993
92b1551b
MH
2994 /*
2995 * Special hack: If a branch is updated directly and HEAD
2996 * points to it (may happen on the remote side of a push
2997 * for example) then logically the HEAD reflog should be
2998 * updated too.
2999 *
3000 * A generic solution would require reverse symref lookups,
3001 * but finding all symrefs pointing to a given branch would be
3002 * rather costly for this rare event (the direct update of a
3003 * branch) to be worth it. So let's cheat and check with HEAD
3004 * only, which should cover 99% of all usage scenarios (even
3005 * 100% of the default ones).
3006 *
3007 * So if HEAD is a symbolic reference, then record the name of
3008 * the reference that it points to. If we see an update of
3009 * head_ref within the transaction, then split_head_update()
3010 * arranges for the reflog of HEAD to be updated, too.
3011 */
2f40e954
NTND
3012 head_ref = refs_resolve_refdup(ref_store, "HEAD",
3013 RESOLVE_REF_NO_RECURSE,
3014 head_oid.hash, &head_type);
92b1551b
MH
3015
3016 if (head_ref && !(head_type & REF_ISSYMREF)) {
3017 free(head_ref);
3018 head_ref = NULL;
3019 }
3020
7bd9bcf3
MH
3021 /*
3022 * Acquire all locks, verify old values if provided, check
3023 * that new values are valid, and write new values to the
3024 * lockfiles, ready to be activated. Only keep one lockfile
3025 * open at a time to avoid running out of file descriptors.
3026 */
efe47281
MH
3027 for (i = 0; i < transaction->nr; i++) {
3028 struct ref_update *update = transaction->updates[i];
7bd9bcf3 3029
b3bbbc5c
MH
3030 ret = lock_ref_for_update(refs, update, transaction,
3031 head_ref, &affected_refnames, err);
165056b2 3032 if (ret)
7bd9bcf3 3033 goto cleanup;
7bd9bcf3 3034 }
7bd9bcf3 3035
7bd9bcf3 3036 /* Perform updates first so live commits remain referenced */
efe47281
MH
3037 for (i = 0; i < transaction->nr; i++) {
3038 struct ref_update *update = transaction->updates[i];
7d618264 3039 struct ref_lock *lock = update->backend_data;
7bd9bcf3 3040
d99aa884
DT
3041 if (update->flags & REF_NEEDS_COMMIT ||
3042 update->flags & REF_LOG_ONLY) {
802de3da
NTND
3043 if (files_log_ref_write(refs,
3044 lock->ref_name,
81b1b6d4
MH
3045 lock->old_oid.hash,
3046 update->new_sha1,
3047 update->msg, update->flags,
3048 err)) {
92b1551b
MH
3049 char *old_msg = strbuf_detach(err, NULL);
3050
3051 strbuf_addf(err, "cannot update the ref '%s': %s",
3052 lock->ref_name, old_msg);
3053 free(old_msg);
3054 unlock_ref(lock);
7d618264 3055 update->backend_data = NULL;
7bd9bcf3
MH
3056 ret = TRANSACTION_GENERIC_ERROR;
3057 goto cleanup;
7bd9bcf3
MH
3058 }
3059 }
7bd9bcf3 3060 if (update->flags & REF_NEEDS_COMMIT) {
00eebe35 3061 clear_loose_ref_cache(refs);
92b1551b
MH
3062 if (commit_ref(lock)) {
3063 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
3064 unlock_ref(lock);
7d618264 3065 update->backend_data = NULL;
7bd9bcf3
MH
3066 ret = TRANSACTION_GENERIC_ERROR;
3067 goto cleanup;
7bd9bcf3
MH
3068 }
3069 }
3070 }
7bd9bcf3 3071 /* Perform deletes now that updates are safely completed */
efe47281
MH
3072 for (i = 0; i < transaction->nr; i++) {
3073 struct ref_update *update = transaction->updates[i];
7d618264 3074 struct ref_lock *lock = update->backend_data;
7bd9bcf3 3075
d99aa884
DT
3076 if (update->flags & REF_DELETING &&
3077 !(update->flags & REF_LOG_ONLY)) {
ce0af24d
MH
3078 if (!(update->type & REF_ISPACKED) ||
3079 update->type & REF_ISSYMREF) {
3080 /* It is a loose reference. */
e9dcc305 3081 strbuf_reset(&sb);
19e02f4f 3082 files_ref_path(refs, &sb, lock->ref_name);
e9dcc305 3083 if (unlink_or_msg(sb.buf, err)) {
ce0af24d
MH
3084 ret = TRANSACTION_GENERIC_ERROR;
3085 goto cleanup;
3086 }
44639777 3087 update->flags |= REF_DELETED_LOOSE;
7bd9bcf3
MH
3088 }
3089
3090 if (!(update->flags & REF_ISPRUNING))
3091 string_list_append(&refs_to_delete,
7d618264 3092 lock->ref_name);
7bd9bcf3
MH
3093 }
3094 }
3095
0a95ac5f 3096 if (repack_without_refs(refs, &refs_to_delete, err)) {
7bd9bcf3
MH
3097 ret = TRANSACTION_GENERIC_ERROR;
3098 goto cleanup;
3099 }
44639777
MH
3100
3101 /* Delete the reflogs of any references that were deleted: */
3102 for_each_string_list_item(ref_to_delete, &refs_to_delete) {
e9dcc305 3103 strbuf_reset(&sb);
802de3da 3104 files_reflog_path(refs, &sb, ref_to_delete->string);
e9dcc305 3105 if (!unlink_or_warn(sb.buf))
802de3da 3106 try_remove_empty_parents(refs, ref_to_delete->string,
44639777
MH
3107 REMOVE_EMPTY_PARENTS_REFLOG);
3108 }
3109
00eebe35 3110 clear_loose_ref_cache(refs);
7bd9bcf3
MH
3111
3112cleanup:
e9dcc305 3113 strbuf_release(&sb);
7bd9bcf3
MH
3114 transaction->state = REF_TRANSACTION_CLOSED;
3115
44639777
MH
3116 for (i = 0; i < transaction->nr; i++) {
3117 struct ref_update *update = transaction->updates[i];
3118 struct ref_lock *lock = update->backend_data;
3119
3120 if (lock)
3121 unlock_ref(lock);
3122
3123 if (update->flags & REF_DELETED_LOOSE) {
3124 /*
3125 * The loose reference was deleted. Delete any
3126 * empty parent directories. (Note that this
3127 * can only work because we have already
3128 * removed the lockfile.)
3129 */
802de3da 3130 try_remove_empty_parents(refs, update->refname,
44639777
MH
3131 REMOVE_EMPTY_PARENTS_REF);
3132 }
3133 }
3134
7bd9bcf3 3135 string_list_clear(&refs_to_delete, 0);
92b1551b 3136 free(head_ref);
7bd9bcf3 3137 string_list_clear(&affected_refnames, 0);
92b1551b 3138
7bd9bcf3
MH
3139 return ret;
3140}
3141
3142static int ref_present(const char *refname,
3143 const struct object_id *oid, int flags, void *cb_data)
3144{
3145 struct string_list *affected_refnames = cb_data;
3146
3147 return string_list_has_string(affected_refnames, refname);
3148}
3149
fc681463
DT
3150static int files_initial_transaction_commit(struct ref_store *ref_store,
3151 struct ref_transaction *transaction,
3152 struct strbuf *err)
7bd9bcf3 3153{
d99825ab 3154 struct files_ref_store *refs =
9e7ec634
NTND
3155 files_downcast(ref_store, REF_STORE_WRITE,
3156 "initial_ref_transaction_commit");
7bd9bcf3 3157 int ret = 0, i;
7bd9bcf3
MH
3158 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
3159
3160 assert(err);
3161
3162 if (transaction->state != REF_TRANSACTION_OPEN)
3163 die("BUG: commit called for transaction that is not open");
3164
3165 /* Fail if a refname appears more than once in the transaction: */
efe47281
MH
3166 for (i = 0; i < transaction->nr; i++)
3167 string_list_append(&affected_refnames,
3168 transaction->updates[i]->refname);
7bd9bcf3
MH
3169 string_list_sort(&affected_refnames);
3170 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3171 ret = TRANSACTION_GENERIC_ERROR;
3172 goto cleanup;
3173 }
3174
3175 /*
3176 * It's really undefined to call this function in an active
3177 * repository or when there are existing references: we are
3178 * only locking and changing packed-refs, so (1) any
3179 * simultaneous processes might try to change a reference at
3180 * the same time we do, and (2) any existing loose versions of
3181 * the references that we are setting would have precedence
3182 * over our values. But some remote helpers create the remote
3183 * "HEAD" and "master" branches before calling this function,
3184 * so here we really only check that none of the references
3185 * that we are creating already exists.
3186 */
2f40e954
NTND
3187 if (refs_for_each_rawref(&refs->base, ref_present,
3188 &affected_refnames))
7bd9bcf3
MH
3189 die("BUG: initial ref transaction called with existing refs");
3190
efe47281
MH
3191 for (i = 0; i < transaction->nr; i++) {
3192 struct ref_update *update = transaction->updates[i];
7bd9bcf3
MH
3193
3194 if ((update->flags & REF_HAVE_OLD) &&
3195 !is_null_sha1(update->old_sha1))
3196 die("BUG: initial ref transaction with old_sha1 set");
7d2df051
NTND
3197 if (refs_verify_refname_available(&refs->base, update->refname,
3198 &affected_refnames, NULL,
3199 err)) {
7bd9bcf3
MH
3200 ret = TRANSACTION_NAME_CONFLICT;
3201 goto cleanup;
3202 }
3203 }
3204
49c0df6a 3205 if (lock_packed_refs(refs, 0)) {
7bd9bcf3
MH
3206 strbuf_addf(err, "unable to lock packed-refs file: %s",
3207 strerror(errno));
3208 ret = TRANSACTION_GENERIC_ERROR;
3209 goto cleanup;
3210 }
3211
efe47281
MH
3212 for (i = 0; i < transaction->nr; i++) {
3213 struct ref_update *update = transaction->updates[i];
7bd9bcf3
MH
3214
3215 if ((update->flags & REF_HAVE_NEW) &&
3216 !is_null_sha1(update->new_sha1))
d99825ab 3217 add_packed_ref(refs, update->refname, update->new_sha1);
7bd9bcf3
MH
3218 }
3219
49c0df6a 3220 if (commit_packed_refs(refs)) {
7bd9bcf3
MH
3221 strbuf_addf(err, "unable to commit packed-refs file: %s",
3222 strerror(errno));
3223 ret = TRANSACTION_GENERIC_ERROR;
3224 goto cleanup;
3225 }
3226
3227cleanup:
3228 transaction->state = REF_TRANSACTION_CLOSED;
3229 string_list_clear(&affected_refnames, 0);
3230 return ret;
3231}
3232
3233struct expire_reflog_cb {
3234 unsigned int flags;
3235 reflog_expiry_should_prune_fn *should_prune_fn;
3236 void *policy_cb;
3237 FILE *newlog;
9461d272 3238 struct object_id last_kept_oid;
7bd9bcf3
MH
3239};
3240
9461d272 3241static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
7bd9bcf3
MH
3242 const char *email, unsigned long timestamp, int tz,
3243 const char *message, void *cb_data)
3244{
3245 struct expire_reflog_cb *cb = cb_data;
3246 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
3247
3248 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
9461d272 3249 ooid = &cb->last_kept_oid;
7bd9bcf3 3250
9461d272 3251 if ((*cb->should_prune_fn)(ooid->hash, noid->hash, email, timestamp, tz,
7bd9bcf3
MH
3252 message, policy_cb)) {
3253 if (!cb->newlog)
3254 printf("would prune %s", message);
3255 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3256 printf("prune %s", message);
3257 } else {
3258 if (cb->newlog) {
3259 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
9461d272 3260 oid_to_hex(ooid), oid_to_hex(noid),
7bd9bcf3 3261 email, timestamp, tz, message);
9461d272 3262 oidcpy(&cb->last_kept_oid, noid);
7bd9bcf3
MH
3263 }
3264 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3265 printf("keep %s", message);
3266 }
3267 return 0;
3268}
3269
e3688bd6
DT
3270static int files_reflog_expire(struct ref_store *ref_store,
3271 const char *refname, const unsigned char *sha1,
3272 unsigned int flags,
3273 reflog_expiry_prepare_fn prepare_fn,
3274 reflog_expiry_should_prune_fn should_prune_fn,
3275 reflog_expiry_cleanup_fn cleanup_fn,
3276 void *policy_cb_data)
7bd9bcf3 3277{
7eb27cdf 3278 struct files_ref_store *refs =
9e7ec634 3279 files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
7bd9bcf3
MH
3280 static struct lock_file reflog_lock;
3281 struct expire_reflog_cb cb;
3282 struct ref_lock *lock;
802de3da 3283 struct strbuf log_file_sb = STRBUF_INIT;
7bd9bcf3
MH
3284 char *log_file;
3285 int status = 0;
3286 int type;
3287 struct strbuf err = STRBUF_INIT;
3288
3289 memset(&cb, 0, sizeof(cb));
3290 cb.flags = flags;
3291 cb.policy_cb = policy_cb_data;
3292 cb.should_prune_fn = should_prune_fn;
3293
3294 /*
3295 * The reflog file is locked by holding the lock on the
3296 * reference itself, plus we might need to update the
3297 * reference if --updateref was specified:
3298 */
7eb27cdf
MH
3299 lock = lock_ref_sha1_basic(refs, refname, sha1,
3300 NULL, NULL, REF_NODEREF,
41d796ed 3301 &type, &err);
7bd9bcf3
MH
3302 if (!lock) {
3303 error("cannot lock ref '%s': %s", refname, err.buf);
3304 strbuf_release(&err);
3305 return -1;
3306 }
2f40e954 3307 if (!refs_reflog_exists(ref_store, refname)) {
7bd9bcf3
MH
3308 unlock_ref(lock);
3309 return 0;
3310 }
3311
802de3da
NTND
3312 files_reflog_path(refs, &log_file_sb, refname);
3313 log_file = strbuf_detach(&log_file_sb, NULL);
7bd9bcf3
MH
3314 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3315 /*
3316 * Even though holding $GIT_DIR/logs/$reflog.lock has
3317 * no locking implications, we use the lock_file
3318 * machinery here anyway because it does a lot of the
3319 * work we need, including cleaning up if the program
3320 * exits unexpectedly.
3321 */
3322 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
3323 struct strbuf err = STRBUF_INIT;
3324 unable_to_lock_message(log_file, errno, &err);
3325 error("%s", err.buf);
3326 strbuf_release(&err);
3327 goto failure;
3328 }
3329 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
3330 if (!cb.newlog) {
3331 error("cannot fdopen %s (%s)",
3332 get_lock_file_path(&reflog_lock), strerror(errno));
3333 goto failure;
3334 }
3335 }
3336
3337 (*prepare_fn)(refname, sha1, cb.policy_cb);
2f40e954 3338 refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
7bd9bcf3
MH
3339 (*cleanup_fn)(cb.policy_cb);
3340
3341 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3342 /*
3343 * It doesn't make sense to adjust a reference pointed
3344 * to by a symbolic ref based on expiring entries in
3345 * the symbolic reference's reflog. Nor can we update
3346 * a reference if there are no remaining reflog
3347 * entries.
3348 */
3349 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
3350 !(type & REF_ISSYMREF) &&
9461d272 3351 !is_null_oid(&cb.last_kept_oid);
7bd9bcf3
MH
3352
3353 if (close_lock_file(&reflog_lock)) {
3354 status |= error("couldn't write %s: %s", log_file,
3355 strerror(errno));
3356 } else if (update &&
3357 (write_in_full(get_lock_file_fd(lock->lk),
9461d272 3358 oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
7bd9bcf3
MH
3359 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||
3360 close_ref(lock) < 0)) {
3361 status |= error("couldn't write %s",
3362 get_lock_file_path(lock->lk));
3363 rollback_lock_file(&reflog_lock);
3364 } else if (commit_lock_file(&reflog_lock)) {
e0048d3e 3365 status |= error("unable to write reflog '%s' (%s)",
7bd9bcf3
MH
3366 log_file, strerror(errno));
3367 } else if (update && commit_ref(lock)) {
3368 status |= error("couldn't set %s", lock->ref_name);
3369 }
3370 }
3371 free(log_file);
3372 unlock_ref(lock);
3373 return status;
3374
3375 failure:
3376 rollback_lock_file(&reflog_lock);
3377 free(log_file);
3378 unlock_ref(lock);
3379 return -1;
3380}
3dce444f 3381
6fb5acfd
DT
3382static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
3383{
19e02f4f 3384 struct files_ref_store *refs =
9e7ec634 3385 files_downcast(ref_store, REF_STORE_WRITE, "init_db");
e9dcc305
NTND
3386 struct strbuf sb = STRBUF_INIT;
3387
6fb5acfd
DT
3388 /*
3389 * Create .git/refs/{heads,tags}
3390 */
19e02f4f 3391 files_ref_path(refs, &sb, "refs/heads");
e9dcc305
NTND
3392 safe_create_dir(sb.buf, 1);
3393
3394 strbuf_reset(&sb);
19e02f4f 3395 files_ref_path(refs, &sb, "refs/tags");
e9dcc305
NTND
3396 safe_create_dir(sb.buf, 1);
3397
3398 strbuf_release(&sb);
6fb5acfd
DT
3399 return 0;
3400}
3401
3dce444f
RS
3402struct ref_storage_be refs_be_files = {
3403 NULL,
00eebe35 3404 "files",
127b42a1 3405 files_ref_store_create,
6fb5acfd 3406 files_init_db,
e1e33b72 3407 files_transaction_commit,
fc681463 3408 files_initial_transaction_commit,
e1e33b72 3409
8231527e 3410 files_pack_refs,
bd427cf2 3411 files_peel_ref,
284689ba 3412 files_create_symref,
a27dcf89 3413 files_delete_refs,
9b6b40d9 3414 files_rename_ref,
8231527e 3415
1a769003 3416 files_ref_iterator_begin,
62665823 3417 files_read_raw_ref,
e3688bd6
DT
3418
3419 files_reflog_iterator_begin,
3420 files_for_each_reflog_ent,
3421 files_for_each_reflog_ent_reverse,
3422 files_reflog_exists,
3423 files_create_reflog,
3424 files_delete_reflog,
3425 files_reflog_expire
3dce444f 3426};