ref_cache: remove support for storing peeled values
[git/git.git] / refs / packed-backend.c
1 #include "../cache.h"
2 #include "../config.h"
3 #include "../refs.h"
4 #include "refs-internal.h"
5 #include "packed-backend.h"
6 #include "../iterator.h"
7 #include "../lockfile.h"
8
9 enum mmap_strategy {
10 /*
11 * Don't use mmap() at all for reading `packed-refs`.
12 */
13 MMAP_NONE,
14
15 /*
16 * Can use mmap() for reading `packed-refs`, but the file must
17 * not remain mmapped. This is the usual option on Windows,
18 * where you cannot rename a new version of a file onto a file
19 * that is currently mmapped.
20 */
21 MMAP_TEMPORARY,
22
23 /*
24 * It is OK to leave the `packed-refs` file mmapped while
25 * arbitrary other code is running.
26 */
27 MMAP_OK
28 };
29
30 #if defined(NO_MMAP)
31 static enum mmap_strategy mmap_strategy = MMAP_NONE;
32 #elif defined(MMAP_PREVENTS_DELETE)
33 static enum mmap_strategy mmap_strategy = MMAP_TEMPORARY;
34 #else
35 static enum mmap_strategy mmap_strategy = MMAP_OK;
36 #endif
37
38 struct packed_ref_store;
39
40 struct packed_ref_cache {
41 /*
42 * A back-pointer to the packed_ref_store with which this
43 * cache is associated:
44 */
45 struct packed_ref_store *refs;
46
47 /* Is the `packed-refs` file currently mmapped? */
48 int mmapped;
49
50 /*
51 * The contents of the `packed-refs` file. If the file was
52 * already sorted, this points at the mmapped contents of the
53 * file. If not, this points at heap-allocated memory
54 * containing the contents, sorted. If there were no contents
55 * (e.g., because the file didn't exist), `buf` and `eof` are
56 * both NULL.
57 */
58 char *buf, *eof;
59
60 /* The size of the header line, if any; otherwise, 0: */
61 size_t header_len;
62
63 /*
64 * What is the peeled state of this cache? (This is usually
65 * determined from the header of the "packed-refs" file.)
66 */
67 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled;
68
69 /*
70 * Count of references to the data structure in this instance,
71 * including the pointer from files_ref_store::packed if any.
72 * The data will not be freed as long as the reference count
73 * is nonzero.
74 */
75 unsigned int referrers;
76
77 /* The metadata from when this packed-refs cache was read */
78 struct stat_validity validity;
79 };
80
81 /*
82 * A container for `packed-refs`-related data. It is not (yet) a
83 * `ref_store`.
84 */
85 struct packed_ref_store {
86 struct ref_store base;
87
88 unsigned int store_flags;
89
90 /* The path of the "packed-refs" file: */
91 char *path;
92
93 /*
94 * A cache of the values read from the `packed-refs` file, if
95 * it might still be current; otherwise, NULL.
96 */
97 struct packed_ref_cache *cache;
98
99 /*
100 * Lock used for the "packed-refs" file. Note that this (and
101 * thus the enclosing `packed_ref_store`) must not be freed.
102 */
103 struct lock_file lock;
104
105 /*
106 * Temporary file used when rewriting new contents to the
107 * "packed-refs" file. Note that this (and thus the enclosing
108 * `packed_ref_store`) must not be freed.
109 */
110 struct tempfile tempfile;
111 };
112
113 /*
114 * Increment the reference count of *packed_refs.
115 */
116 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
117 {
118 packed_refs->referrers++;
119 }
120
121 /*
122 * If the buffer in `packed_refs` is active, then either munmap the
123 * memory and close the file, or free the memory. Then set the buffer
124 * pointers to NULL.
125 */
126 static void release_packed_ref_buffer(struct packed_ref_cache *packed_refs)
127 {
128 if (packed_refs->mmapped) {
129 if (munmap(packed_refs->buf,
130 packed_refs->eof - packed_refs->buf))
131 die_errno("error ummapping packed-refs file %s",
132 packed_refs->refs->path);
133 packed_refs->mmapped = 0;
134 } else {
135 free(packed_refs->buf);
136 }
137 packed_refs->buf = packed_refs->eof = NULL;
138 packed_refs->header_len = 0;
139 }
140
141 /*
142 * Decrease the reference count of *packed_refs. If it goes to zero,
143 * free *packed_refs and return true; otherwise return false.
144 */
145 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
146 {
147 if (!--packed_refs->referrers) {
148 stat_validity_clear(&packed_refs->validity);
149 release_packed_ref_buffer(packed_refs);
150 free(packed_refs);
151 return 1;
152 } else {
153 return 0;
154 }
155 }
156
157 struct ref_store *packed_ref_store_create(const char *path,
158 unsigned int store_flags)
159 {
160 struct packed_ref_store *refs = xcalloc(1, sizeof(*refs));
161 struct ref_store *ref_store = (struct ref_store *)refs;
162
163 base_ref_store_init(ref_store, &refs_be_packed);
164 refs->store_flags = store_flags;
165
166 refs->path = xstrdup(path);
167 return ref_store;
168 }
169
170 /*
171 * Downcast `ref_store` to `packed_ref_store`. Die if `ref_store` is
172 * not a `packed_ref_store`. Also die if `packed_ref_store` doesn't
173 * support at least the flags specified in `required_flags`. `caller`
174 * is used in any necessary error messages.
175 */
176 static struct packed_ref_store *packed_downcast(struct ref_store *ref_store,
177 unsigned int required_flags,
178 const char *caller)
179 {
180 struct packed_ref_store *refs;
181
182 if (ref_store->be != &refs_be_packed)
183 die("BUG: ref_store is type \"%s\" not \"packed\" in %s",
184 ref_store->be->name, caller);
185
186 refs = (struct packed_ref_store *)ref_store;
187
188 if ((refs->store_flags & required_flags) != required_flags)
189 die("BUG: unallowed operation (%s), requires %x, has %x\n",
190 caller, required_flags, refs->store_flags);
191
192 return refs;
193 }
194
195 static void clear_packed_ref_cache(struct packed_ref_store *refs)
196 {
197 if (refs->cache) {
198 struct packed_ref_cache *cache = refs->cache;
199
200 refs->cache = NULL;
201 release_packed_ref_cache(cache);
202 }
203 }
204
205 static NORETURN void die_unterminated_line(const char *path,
206 const char *p, size_t len)
207 {
208 if (len < 80)
209 die("unterminated line in %s: %.*s", path, (int)len, p);
210 else
211 die("unterminated line in %s: %.75s...", path, p);
212 }
213
214 static NORETURN void die_invalid_line(const char *path,
215 const char *p, size_t len)
216 {
217 const char *eol = memchr(p, '\n', len);
218
219 if (!eol)
220 die_unterminated_line(path, p, len);
221 else if (eol - p < 80)
222 die("unexpected line in %s: %.*s", path, (int)(eol - p), p);
223 else
224 die("unexpected line in %s: %.75s...", path, p);
225
226 }
227
228 /*
229 * This value is set in `base.flags` if the peeled value of the
230 * current reference is known. In that case, `peeled` contains the
231 * correct peeled value for the reference, which might be `null_sha1`
232 * if the reference is not a tag or if it is broken.
233 */
234 #define REF_KNOWS_PEELED 0x40
235
236 /*
237 * An iterator over a packed-refs file that is currently mmapped.
238 */
239 struct mmapped_ref_iterator {
240 struct ref_iterator base;
241
242 struct packed_ref_cache *packed_refs;
243
244 /* The current position in the mmapped file: */
245 const char *pos;
246
247 /* The end of the mmapped file: */
248 const char *eof;
249
250 struct object_id oid, peeled;
251
252 struct strbuf refname_buf;
253 };
254
255 static int mmapped_ref_iterator_advance(struct ref_iterator *ref_iterator)
256 {
257 struct mmapped_ref_iterator *iter =
258 (struct mmapped_ref_iterator *)ref_iterator;
259 const char *p = iter->pos, *eol;
260
261 strbuf_reset(&iter->refname_buf);
262
263 if (iter->pos == iter->eof)
264 return ref_iterator_abort(ref_iterator);
265
266 iter->base.flags = REF_ISPACKED;
267
268 if (iter->eof - p < GIT_SHA1_HEXSZ + 2 ||
269 parse_oid_hex(p, &iter->oid, &p) ||
270 !isspace(*p++))
271 die_invalid_line(iter->packed_refs->refs->path,
272 iter->pos, iter->eof - iter->pos);
273
274 eol = memchr(p, '\n', iter->eof - p);
275 if (!eol)
276 die_unterminated_line(iter->packed_refs->refs->path,
277 iter->pos, iter->eof - iter->pos);
278
279 strbuf_add(&iter->refname_buf, p, eol - p);
280 iter->base.refname = iter->refname_buf.buf;
281
282 if (check_refname_format(iter->base.refname, REFNAME_ALLOW_ONELEVEL)) {
283 if (!refname_is_safe(iter->base.refname))
284 die("packed refname is dangerous: %s",
285 iter->base.refname);
286 oidclr(&iter->oid);
287 iter->base.flags |= REF_BAD_NAME | REF_ISBROKEN;
288 }
289 if (iter->packed_refs->peeled == PEELED_FULLY ||
290 (iter->packed_refs->peeled == PEELED_TAGS &&
291 starts_with(iter->base.refname, "refs/tags/")))
292 iter->base.flags |= REF_KNOWS_PEELED;
293
294 iter->pos = eol + 1;
295
296 if (iter->pos < iter->eof && *iter->pos == '^') {
297 p = iter->pos + 1;
298 if (iter->eof - p < GIT_SHA1_HEXSZ + 1 ||
299 parse_oid_hex(p, &iter->peeled, &p) ||
300 *p++ != '\n')
301 die_invalid_line(iter->packed_refs->refs->path,
302 iter->pos, iter->eof - iter->pos);
303 iter->pos = p;
304
305 /*
306 * Regardless of what the file header said, we
307 * definitely know the value of *this* reference. But
308 * we suppress it if the reference is broken:
309 */
310 if ((iter->base.flags & REF_ISBROKEN)) {
311 oidclr(&iter->peeled);
312 iter->base.flags &= ~REF_KNOWS_PEELED;
313 } else {
314 iter->base.flags |= REF_KNOWS_PEELED;
315 }
316 } else {
317 oidclr(&iter->peeled);
318 }
319
320 return ITER_OK;
321 }
322
323 static int mmapped_ref_iterator_peel(struct ref_iterator *ref_iterator,
324 struct object_id *peeled)
325 {
326 struct mmapped_ref_iterator *iter =
327 (struct mmapped_ref_iterator *)ref_iterator;
328
329 if ((iter->base.flags & REF_KNOWS_PEELED)) {
330 oidcpy(peeled, &iter->peeled);
331 return is_null_oid(&iter->peeled) ? -1 : 0;
332 } else if ((iter->base.flags & (REF_ISBROKEN | REF_ISSYMREF))) {
333 return -1;
334 } else {
335 return !!peel_object(iter->oid.hash, peeled->hash);
336 }
337 }
338
339 static int mmapped_ref_iterator_abort(struct ref_iterator *ref_iterator)
340 {
341 struct mmapped_ref_iterator *iter =
342 (struct mmapped_ref_iterator *)ref_iterator;
343
344 release_packed_ref_cache(iter->packed_refs);
345 strbuf_release(&iter->refname_buf);
346 base_ref_iterator_free(ref_iterator);
347 return ITER_DONE;
348 }
349
350 static struct ref_iterator_vtable mmapped_ref_iterator_vtable = {
351 mmapped_ref_iterator_advance,
352 mmapped_ref_iterator_peel,
353 mmapped_ref_iterator_abort
354 };
355
356 struct ref_iterator *mmapped_ref_iterator_begin(
357 struct packed_ref_cache *packed_refs,
358 const char *pos, const char *eof)
359 {
360 struct mmapped_ref_iterator *iter = xcalloc(1, sizeof(*iter));
361 struct ref_iterator *ref_iterator = &iter->base;
362
363 if (!packed_refs->buf)
364 return empty_ref_iterator_begin();
365
366 base_ref_iterator_init(ref_iterator, &mmapped_ref_iterator_vtable, 1);
367
368 iter->packed_refs = packed_refs;
369 acquire_packed_ref_cache(iter->packed_refs);
370 iter->pos = pos;
371 iter->eof = eof;
372 strbuf_init(&iter->refname_buf, 0);
373
374 iter->base.oid = &iter->oid;
375
376 return ref_iterator;
377 }
378
379 struct packed_ref_entry {
380 const char *start;
381 size_t len;
382 };
383
384 static int cmp_packed_ref_entries(const void *v1, const void *v2)
385 {
386 const struct packed_ref_entry *e1 = v1, *e2 = v2;
387 const char *r1 = e1->start + GIT_SHA1_HEXSZ + 1;
388 const char *r2 = e2->start + GIT_SHA1_HEXSZ + 1;
389
390 while (1) {
391 if (*r1 == '\n')
392 return *r2 == '\n' ? 0 : -1;
393 if (*r1 != *r2) {
394 if (*r2 == '\n')
395 return 1;
396 else
397 return (unsigned char)*r1 < (unsigned char)*r2 ? -1 : +1;
398 }
399 r1++;
400 r2++;
401 }
402 }
403
404 /*
405 * Compare a packed-refs record pointed to by `rec` to the specified
406 * NUL-terminated refname.
407 */
408 static int cmp_entry_to_refname(const char *rec, const char *refname)
409 {
410 const char *r1 = rec + GIT_SHA1_HEXSZ + 1;
411 const char *r2 = refname;
412
413 while (1) {
414 if (*r1 == '\n')
415 return *r2 ? -1 : 0;
416 if (!*r2)
417 return 1;
418 if (*r1 != *r2)
419 return (unsigned char)*r1 < (unsigned char)*r2 ? -1 : +1;
420 r1++;
421 r2++;
422 }
423 }
424
425 /*
426 * `packed_refs->buf` is not known to be sorted. Check whether it is,
427 * and if not, sort it into new memory and munmap/free the old
428 * storage.
429 */
430 static void sort_packed_refs(struct packed_ref_cache *packed_refs)
431 {
432 struct packed_ref_entry *entries = NULL;
433 size_t alloc = 0, nr = 0;
434 int sorted = 1;
435 const char *pos, *eof, *eol;
436 size_t len, i;
437 char *new_buffer, *dst;
438
439 pos = packed_refs->buf + packed_refs->header_len;
440 eof = packed_refs->eof;
441 len = eof - pos;
442
443 if (!len)
444 return;
445
446 /*
447 * Initialize entries based on a crude estimate of the number
448 * of references in the file (we'll grow it below if needed):
449 */
450 ALLOC_GROW(entries, len / 80 + 20, alloc);
451
452 while (pos < eof) {
453 eol = memchr(pos, '\n', eof - pos);
454 if (!eol)
455 /* The safety check should prevent this. */
456 BUG("unterminated line found in packed-refs");
457 if (eol - pos < GIT_SHA1_HEXSZ + 2)
458 die_invalid_line(packed_refs->refs->path,
459 pos, eof - pos);
460 eol++;
461 if (eol < eof && *eol == '^') {
462 /*
463 * Keep any peeled line together with its
464 * reference:
465 */
466 const char *peeled_start = eol;
467
468 eol = memchr(peeled_start, '\n', eof - peeled_start);
469 if (!eol)
470 /* The safety check should prevent this. */
471 BUG("unterminated peeled line found in packed-refs");
472 eol++;
473 }
474
475 ALLOC_GROW(entries, nr + 1, alloc);
476 entries[nr].start = pos;
477 entries[nr].len = eol - pos;
478 nr++;
479
480 if (sorted &&
481 nr > 1 &&
482 cmp_packed_ref_entries(&entries[nr - 2],
483 &entries[nr - 1]) >= 0)
484 sorted = 0;
485
486 pos = eol;
487 }
488
489 if (sorted)
490 goto cleanup;
491
492 /* We need to sort the memory. First we sort the entries array: */
493 QSORT(entries, nr, cmp_packed_ref_entries);
494
495 /*
496 * Allocate a new chunk of memory, and copy the old memory to
497 * the new in the order indicated by `entries` (not bothering
498 * with the header line):
499 */
500 new_buffer = xmalloc(len);
501 for (dst = new_buffer, i = 0; i < nr; i++) {
502 memcpy(dst, entries[i].start, entries[i].len);
503 dst += entries[i].len;
504 }
505
506 /*
507 * Now munmap the old buffer and use the sorted buffer in its
508 * place:
509 */
510 release_packed_ref_buffer(packed_refs);
511 packed_refs->buf = new_buffer;
512 packed_refs->eof = new_buffer + len;
513 packed_refs->header_len = 0;
514
515 cleanup:
516 free(entries);
517 }
518
519 /*
520 * Return a pointer to the start of the record that contains the
521 * character `*p` (which must be within the buffer). If no other
522 * record start is found, return `buf`.
523 */
524 static const char *find_start_of_record(const char *buf, const char *p)
525 {
526 while (p > buf && (p[-1] != '\n' || p[0] == '^'))
527 p--;
528 return p;
529 }
530
531 /*
532 * Return a pointer to the start of the record following the record
533 * that contains `*p`. If none is found before `end`, return `end`.
534 */
535 static const char *find_end_of_record(const char *p, const char *end)
536 {
537 while (++p < end && (p[-1] != '\n' || p[0] == '^'))
538 ;
539 return p;
540 }
541
542 /*
543 * We want to be able to compare mmapped reference records quickly,
544 * without totally parsing them. We can do so because the records are
545 * LF-terminated, and the refname should start exactly (GIT_SHA1_HEXSZ
546 * + 1) bytes past the beginning of the record.
547 *
548 * But what if the `packed-refs` file contains garbage? We're willing
549 * to tolerate not detecting the problem, as long as we don't produce
550 * totally garbled output (we can't afford to check the integrity of
551 * the whole file during every Git invocation). But we do want to be
552 * sure that we never read past the end of the buffer in memory and
553 * perform an illegal memory access.
554 *
555 * Guarantee that minimum level of safety by verifying that the last
556 * record in the file is LF-terminated, and that it has at least
557 * (GIT_SHA1_HEXSZ + 1) characters before the LF. Die if either of
558 * these checks fails.
559 */
560 static void verify_buffer_safe(struct packed_ref_cache *packed_refs)
561 {
562 const char *buf = packed_refs->buf + packed_refs->header_len;
563 const char *eof = packed_refs->eof;
564 const char *last_line;
565
566 if (buf == eof)
567 return;
568
569 last_line = find_start_of_record(buf, eof - 1);
570 if (*(eof - 1) != '\n' || eof - last_line < GIT_SHA1_HEXSZ + 2)
571 die_invalid_line(packed_refs->refs->path,
572 last_line, eof - last_line);
573 }
574
575 /*
576 * Depending on `mmap_strategy`, either mmap or read the contents of
577 * the `packed-refs` file into the `packed_refs` instance. Return 1 if
578 * the file existed and was read, or 0 if the file was absent. Die on
579 * errors.
580 */
581 static int load_contents(struct packed_ref_cache *packed_refs)
582 {
583 int fd;
584 struct stat st;
585 size_t size;
586 ssize_t bytes_read;
587
588 fd = open(packed_refs->refs->path, O_RDONLY);
589 if (fd < 0) {
590 if (errno == ENOENT) {
591 /*
592 * This is OK; it just means that no
593 * "packed-refs" file has been written yet,
594 * which is equivalent to it being empty,
595 * which is its state when initialized with
596 * zeros.
597 */
598 return 0;
599 } else {
600 die_errno("couldn't read %s", packed_refs->refs->path);
601 }
602 }
603
604 stat_validity_update(&packed_refs->validity, fd);
605
606 if (fstat(fd, &st) < 0)
607 die_errno("couldn't stat %s", packed_refs->refs->path);
608 size = xsize_t(st.st_size);
609
610 switch (mmap_strategy) {
611 case MMAP_NONE:
612 packed_refs->buf = xmalloc(size);
613 bytes_read = read_in_full(fd, packed_refs->buf, size);
614 if (bytes_read < 0 || bytes_read != size)
615 die_errno("couldn't read %s", packed_refs->refs->path);
616 packed_refs->eof = packed_refs->buf + size;
617 packed_refs->mmapped = 0;
618 break;
619 case MMAP_TEMPORARY:
620 case MMAP_OK:
621 packed_refs->buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
622 packed_refs->eof = packed_refs->buf + size;
623 packed_refs->mmapped = 1;
624 break;
625 }
626 close(fd);
627
628 return 1;
629 }
630
631 /*
632 * Find the place in `cache->buf` where the start of the record for
633 * `refname` starts. If `mustexist` is true and the reference doesn't
634 * exist, then return NULL. If `mustexist` is false and the reference
635 * doesn't exist, then return the point where that reference would be
636 * inserted. In the latter mode, `refname` doesn't have to be a proper
637 * reference name; for example, one could search for "refs/replace/"
638 * to find the start of any replace references.
639 *
640 * The record is sought using a binary search, so `cache->buf` must be
641 * sorted.
642 */
643 static const char *find_reference_location(struct packed_ref_cache *cache,
644 const char *refname, int mustexist)
645 {
646 /*
647 * This is not *quite* a garden-variety binary search, because
648 * the data we're searching is made up of records, and we
649 * always need to find the beginning of a record to do a
650 * comparison. A "record" here is one line for the reference
651 * itself and zero or one peel lines that start with '^'. Our
652 * loop invariant is described in the next two comments.
653 */
654
655 /*
656 * A pointer to the character at the start of a record whose
657 * preceding records all have reference names that come
658 * *before* `refname`.
659 */
660 const char *lo = cache->buf + cache->header_len;
661
662 /*
663 * A pointer to a the first character of a record whose
664 * reference name comes *after* `refname`.
665 */
666 const char *hi = cache->eof;
667
668 while (lo < hi) {
669 const char *mid, *rec;
670 int cmp;
671
672 mid = lo + (hi - lo) / 2;
673 rec = find_start_of_record(lo, mid);
674 cmp = cmp_entry_to_refname(rec, refname);
675 if (cmp < 0) {
676 lo = find_end_of_record(mid, hi);
677 } else if (cmp > 0) {
678 hi = rec;
679 } else {
680 return rec;
681 }
682 }
683
684 if (mustexist)
685 return NULL;
686 else
687 return lo;
688 }
689
690 /*
691 * Read from the `packed-refs` file into a newly-allocated
692 * `packed_ref_cache` and return it. The return value will already
693 * have its reference count incremented.
694 *
695 * A comment line of the form "# pack-refs with: " may contain zero or
696 * more traits. We interpret the traits as follows:
697 *
698 * Neither `peeled` nor `fully-peeled`:
699 *
700 * Probably no references are peeled. But if the file contains a
701 * peeled value for a reference, we will use it.
702 *
703 * `peeled`:
704 *
705 * References under "refs/tags/", if they *can* be peeled, *are*
706 * peeled in this file. References outside of "refs/tags/" are
707 * probably not peeled even if they could have been, but if we find
708 * a peeled value for such a reference we will use it.
709 *
710 * `fully-peeled`:
711 *
712 * All references in the file that can be peeled are peeled.
713 * Inversely (and this is more important), any references in the
714 * file for which no peeled value is recorded is not peelable. This
715 * trait should typically be written alongside "peeled" for
716 * compatibility with older clients, but we do not require it
717 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
718 *
719 * `sorted`:
720 *
721 * The references in this file are known to be sorted by refname.
722 */
723 static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs)
724 {
725 struct packed_ref_cache *packed_refs = xcalloc(1, sizeof(*packed_refs));
726 int sorted = 0;
727
728 packed_refs->refs = refs;
729 acquire_packed_ref_cache(packed_refs);
730 packed_refs->peeled = PEELED_NONE;
731
732 if (!load_contents(packed_refs))
733 return packed_refs;
734
735 /* If the file has a header line, process it: */
736 if (packed_refs->buf < packed_refs->eof && *packed_refs->buf == '#') {
737 struct strbuf tmp = STRBUF_INIT;
738 char *p;
739 const char *eol;
740 struct string_list traits = STRING_LIST_INIT_NODUP;
741
742 eol = memchr(packed_refs->buf, '\n',
743 packed_refs->eof - packed_refs->buf);
744 if (!eol)
745 die_unterminated_line(refs->path,
746 packed_refs->buf,
747 packed_refs->eof - packed_refs->buf);
748
749 strbuf_add(&tmp, packed_refs->buf, eol - packed_refs->buf);
750
751 if (!skip_prefix(tmp.buf, "# pack-refs with:", (const char **)&p))
752 die_invalid_line(refs->path,
753 packed_refs->buf,
754 packed_refs->eof - packed_refs->buf);
755
756 string_list_split_in_place(&traits, p, ' ', -1);
757
758 if (unsorted_string_list_has_string(&traits, "fully-peeled"))
759 packed_refs->peeled = PEELED_FULLY;
760 else if (unsorted_string_list_has_string(&traits, "peeled"))
761 packed_refs->peeled = PEELED_TAGS;
762
763 sorted = unsorted_string_list_has_string(&traits, "sorted");
764
765 /* perhaps other traits later as well */
766
767 /* The "+ 1" is for the LF character. */
768 packed_refs->header_len = eol + 1 - packed_refs->buf;
769
770 string_list_clear(&traits, 0);
771 strbuf_release(&tmp);
772 }
773
774 verify_buffer_safe(packed_refs);
775
776 if (!sorted) {
777 sort_packed_refs(packed_refs);
778
779 /*
780 * Reordering the records might have moved a short one
781 * to the end of the buffer, so verify the buffer's
782 * safety again:
783 */
784 verify_buffer_safe(packed_refs);
785 }
786
787 if (mmap_strategy != MMAP_OK && packed_refs->mmapped) {
788 /*
789 * We don't want to leave the file mmapped, so we are
790 * forced to make a copy now:
791 */
792 size_t size = packed_refs->eof -
793 (packed_refs->buf + packed_refs->header_len);
794 char *buf_copy = xmalloc(size);
795
796 memcpy(buf_copy, packed_refs->buf + packed_refs->header_len, size);
797 release_packed_ref_buffer(packed_refs);
798 packed_refs->buf = buf_copy;
799 packed_refs->eof = buf_copy + size;
800 }
801
802 return packed_refs;
803 }
804
805 /*
806 * Check that the packed refs cache (if any) still reflects the
807 * contents of the file. If not, clear the cache.
808 */
809 static void validate_packed_ref_cache(struct packed_ref_store *refs)
810 {
811 if (refs->cache &&
812 !stat_validity_check(&refs->cache->validity, refs->path))
813 clear_packed_ref_cache(refs);
814 }
815
816 /*
817 * Get the packed_ref_cache for the specified packed_ref_store,
818 * creating and populating it if it hasn't been read before or if the
819 * file has been changed (according to its `validity` field) since it
820 * was last read. On the other hand, if we hold the lock, then assume
821 * that the file hasn't been changed out from under us, so skip the
822 * extra `stat()` call in `stat_validity_check()`.
823 */
824 static struct packed_ref_cache *get_packed_ref_cache(struct packed_ref_store *refs)
825 {
826 if (!is_lock_file_locked(&refs->lock))
827 validate_packed_ref_cache(refs);
828
829 if (!refs->cache)
830 refs->cache = read_packed_refs(refs);
831
832 return refs->cache;
833 }
834
835 static int packed_read_raw_ref(struct ref_store *ref_store,
836 const char *refname, unsigned char *sha1,
837 struct strbuf *referent, unsigned int *type)
838 {
839 struct packed_ref_store *refs =
840 packed_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
841 struct packed_ref_cache *packed_refs = get_packed_ref_cache(refs);
842 const char *rec;
843
844 *type = 0;
845
846 rec = find_reference_location(packed_refs, refname, 1);
847
848 if (!rec) {
849 /* refname is not a packed reference. */
850 errno = ENOENT;
851 return -1;
852 }
853
854 if (get_sha1_hex(rec, sha1))
855 die_invalid_line(refs->path, rec, packed_refs->eof - rec);
856
857 *type = REF_ISPACKED;
858 return 0;
859 }
860
861 struct packed_ref_iterator {
862 struct ref_iterator base;
863
864 struct packed_ref_cache *cache;
865 struct ref_iterator *iter0;
866 unsigned int flags;
867 };
868
869 static int packed_ref_iterator_advance(struct ref_iterator *ref_iterator)
870 {
871 struct packed_ref_iterator *iter =
872 (struct packed_ref_iterator *)ref_iterator;
873 int ok;
874
875 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
876 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
877 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
878 continue;
879
880 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
881 !ref_resolves_to_object(iter->iter0->refname,
882 iter->iter0->oid,
883 iter->iter0->flags))
884 continue;
885
886 iter->base.refname = iter->iter0->refname;
887 iter->base.oid = iter->iter0->oid;
888 iter->base.flags = iter->iter0->flags;
889 return ITER_OK;
890 }
891
892 iter->iter0 = NULL;
893 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
894 ok = ITER_ERROR;
895
896 return ok;
897 }
898
899 static int packed_ref_iterator_peel(struct ref_iterator *ref_iterator,
900 struct object_id *peeled)
901 {
902 struct packed_ref_iterator *iter =
903 (struct packed_ref_iterator *)ref_iterator;
904
905 return ref_iterator_peel(iter->iter0, peeled);
906 }
907
908 static int packed_ref_iterator_abort(struct ref_iterator *ref_iterator)
909 {
910 struct packed_ref_iterator *iter =
911 (struct packed_ref_iterator *)ref_iterator;
912 int ok = ITER_DONE;
913
914 if (iter->iter0)
915 ok = ref_iterator_abort(iter->iter0);
916
917 release_packed_ref_cache(iter->cache);
918 base_ref_iterator_free(ref_iterator);
919 return ok;
920 }
921
922 static struct ref_iterator_vtable packed_ref_iterator_vtable = {
923 packed_ref_iterator_advance,
924 packed_ref_iterator_peel,
925 packed_ref_iterator_abort
926 };
927
928 static struct ref_iterator *packed_ref_iterator_begin(
929 struct ref_store *ref_store,
930 const char *prefix, unsigned int flags)
931 {
932 struct packed_ref_store *refs;
933 struct packed_ref_cache *packed_refs;
934 const char *start;
935 struct packed_ref_iterator *iter;
936 struct ref_iterator *ref_iterator;
937 unsigned int required_flags = REF_STORE_READ;
938
939 if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
940 required_flags |= REF_STORE_ODB;
941 refs = packed_downcast(ref_store, required_flags, "ref_iterator_begin");
942
943 iter = xcalloc(1, sizeof(*iter));
944 ref_iterator = &iter->base;
945 base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable, 1);
946
947 /*
948 * Note that get_packed_ref_cache() internally checks whether
949 * the packed-ref cache is up to date with what is on disk,
950 * and re-reads it if not.
951 */
952 iter->cache = packed_refs = get_packed_ref_cache(refs);
953 acquire_packed_ref_cache(packed_refs);
954
955 if (prefix && *prefix)
956 start = find_reference_location(packed_refs, prefix, 0);
957 else
958 start = packed_refs->buf + packed_refs->header_len;
959
960 iter->iter0 = mmapped_ref_iterator_begin(packed_refs,
961 start, packed_refs->eof);
962
963 iter->flags = flags;
964
965 if (prefix && *prefix)
966 /* Stop iteration after we've gone *past* prefix: */
967 ref_iterator = prefix_ref_iterator_begin(ref_iterator, prefix, 0);
968
969 return ref_iterator;
970 }
971
972 /*
973 * Write an entry to the packed-refs file for the specified refname.
974 * If peeled is non-NULL, write it as the entry's peeled value. On
975 * error, return a nonzero value and leave errno set at the value left
976 * by the failing call to `fprintf()`.
977 */
978 static int write_packed_entry(FILE *fh, const char *refname,
979 const unsigned char *sha1,
980 const unsigned char *peeled)
981 {
982 if (fprintf(fh, "%s %s\n", sha1_to_hex(sha1), refname) < 0 ||
983 (peeled && fprintf(fh, "^%s\n", sha1_to_hex(peeled)) < 0))
984 return -1;
985
986 return 0;
987 }
988
989 int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
990 {
991 struct packed_ref_store *refs =
992 packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
993 "packed_refs_lock");
994 static int timeout_configured = 0;
995 static int timeout_value = 1000;
996
997 if (!timeout_configured) {
998 git_config_get_int("core.packedrefstimeout", &timeout_value);
999 timeout_configured = 1;
1000 }
1001
1002 /*
1003 * Note that we close the lockfile immediately because we
1004 * don't write new content to it, but rather to a separate
1005 * tempfile.
1006 */
1007 if (hold_lock_file_for_update_timeout(
1008 &refs->lock,
1009 refs->path,
1010 flags, timeout_value) < 0) {
1011 unable_to_lock_message(refs->path, errno, err);
1012 return -1;
1013 }
1014
1015 if (close_lock_file(&refs->lock)) {
1016 strbuf_addf(err, "unable to close %s: %s", refs->path, strerror(errno));
1017 return -1;
1018 }
1019
1020 /*
1021 * Now that we hold the `packed-refs` lock, make sure that our
1022 * cache matches the current version of the file. Normally
1023 * `get_packed_ref_cache()` does that for us, but that
1024 * function assumes that when the file is locked, any existing
1025 * cache is still valid. We've just locked the file, but it
1026 * might have changed the moment *before* we locked it.
1027 */
1028 validate_packed_ref_cache(refs);
1029
1030 /*
1031 * Now make sure that the packed-refs file as it exists in the
1032 * locked state is loaded into the cache:
1033 */
1034 get_packed_ref_cache(refs);
1035 return 0;
1036 }
1037
1038 void packed_refs_unlock(struct ref_store *ref_store)
1039 {
1040 struct packed_ref_store *refs = packed_downcast(
1041 ref_store,
1042 REF_STORE_READ | REF_STORE_WRITE,
1043 "packed_refs_unlock");
1044
1045 if (!is_lock_file_locked(&refs->lock))
1046 die("BUG: packed_refs_unlock() called when not locked");
1047 rollback_lock_file(&refs->lock);
1048 }
1049
1050 int packed_refs_is_locked(struct ref_store *ref_store)
1051 {
1052 struct packed_ref_store *refs = packed_downcast(
1053 ref_store,
1054 REF_STORE_READ | REF_STORE_WRITE,
1055 "packed_refs_is_locked");
1056
1057 return is_lock_file_locked(&refs->lock);
1058 }
1059
1060 /*
1061 * The packed-refs header line that we write out. Perhaps other
1062 * traits will be added later.
1063 *
1064 * Note that earlier versions of Git used to parse these traits by
1065 * looking for " trait " in the line. For this reason, the space after
1066 * the colon and the trailing space are required.
1067 */
1068 static const char PACKED_REFS_HEADER[] =
1069 "# pack-refs with: peeled fully-peeled sorted \n";
1070
1071 static int packed_init_db(struct ref_store *ref_store, struct strbuf *err)
1072 {
1073 /* Nothing to do. */
1074 return 0;
1075 }
1076
1077 /*
1078 * Write the packed-refs from the cache to the packed-refs tempfile,
1079 * incorporating any changes from `updates`. `updates` must be a
1080 * sorted string list whose keys are the refnames and whose util
1081 * values are `struct ref_update *`. On error, rollback the tempfile,
1082 * write an error message to `err`, and return a nonzero value.
1083 *
1084 * The packfile must be locked before calling this function and will
1085 * remain locked when it is done.
1086 */
1087 static int write_with_updates(struct packed_ref_store *refs,
1088 struct string_list *updates,
1089 struct strbuf *err)
1090 {
1091 struct ref_iterator *iter = NULL;
1092 size_t i;
1093 int ok;
1094 FILE *out;
1095 struct strbuf sb = STRBUF_INIT;
1096 char *packed_refs_path;
1097
1098 if (!is_lock_file_locked(&refs->lock))
1099 die("BUG: write_with_updates() called while unlocked");
1100
1101 /*
1102 * If packed-refs is a symlink, we want to overwrite the
1103 * symlinked-to file, not the symlink itself. Also, put the
1104 * staging file next to it:
1105 */
1106 packed_refs_path = get_locked_file_path(&refs->lock);
1107 strbuf_addf(&sb, "%s.new", packed_refs_path);
1108 free(packed_refs_path);
1109 if (create_tempfile(&refs->tempfile, sb.buf) < 0) {
1110 strbuf_addf(err, "unable to create file %s: %s",
1111 sb.buf, strerror(errno));
1112 strbuf_release(&sb);
1113 return -1;
1114 }
1115 strbuf_release(&sb);
1116
1117 out = fdopen_tempfile(&refs->tempfile, "w");
1118 if (!out) {
1119 strbuf_addf(err, "unable to fdopen packed-refs tempfile: %s",
1120 strerror(errno));
1121 goto error;
1122 }
1123
1124 if (fprintf(out, "%s", PACKED_REFS_HEADER) < 0)
1125 goto write_error;
1126
1127 /*
1128 * We iterate in parallel through the current list of refs and
1129 * the list of updates, processing an entry from at least one
1130 * of the lists each time through the loop. When the current
1131 * list of refs is exhausted, set iter to NULL. When the list
1132 * of updates is exhausted, leave i set to updates->nr.
1133 */
1134 iter = packed_ref_iterator_begin(&refs->base, "",
1135 DO_FOR_EACH_INCLUDE_BROKEN);
1136 if ((ok = ref_iterator_advance(iter)) != ITER_OK)
1137 iter = NULL;
1138
1139 i = 0;
1140
1141 while (iter || i < updates->nr) {
1142 struct ref_update *update = NULL;
1143 int cmp;
1144
1145 if (i >= updates->nr) {
1146 cmp = -1;
1147 } else {
1148 update = updates->items[i].util;
1149
1150 if (!iter)
1151 cmp = +1;
1152 else
1153 cmp = strcmp(iter->refname, update->refname);
1154 }
1155
1156 if (!cmp) {
1157 /*
1158 * There is both an old value and an update
1159 * for this reference. Check the old value if
1160 * necessary:
1161 */
1162 if ((update->flags & REF_HAVE_OLD)) {
1163 if (is_null_oid(&update->old_oid)) {
1164 strbuf_addf(err, "cannot update ref '%s': "
1165 "reference already exists",
1166 update->refname);
1167 goto error;
1168 } else if (oidcmp(&update->old_oid, iter->oid)) {
1169 strbuf_addf(err, "cannot update ref '%s': "
1170 "is at %s but expected %s",
1171 update->refname,
1172 oid_to_hex(iter->oid),
1173 oid_to_hex(&update->old_oid));
1174 goto error;
1175 }
1176 }
1177
1178 /* Now figure out what to use for the new value: */
1179 if ((update->flags & REF_HAVE_NEW)) {
1180 /*
1181 * The update takes precedence. Skip
1182 * the iterator over the unneeded
1183 * value.
1184 */
1185 if ((ok = ref_iterator_advance(iter)) != ITER_OK)
1186 iter = NULL;
1187 cmp = +1;
1188 } else {
1189 /*
1190 * The update doesn't actually want to
1191 * change anything. We're done with it.
1192 */
1193 i++;
1194 cmp = -1;
1195 }
1196 } else if (cmp > 0) {
1197 /*
1198 * There is no old value but there is an
1199 * update for this reference. Make sure that
1200 * the update didn't expect an existing value:
1201 */
1202 if ((update->flags & REF_HAVE_OLD) &&
1203 !is_null_oid(&update->old_oid)) {
1204 strbuf_addf(err, "cannot update ref '%s': "
1205 "reference is missing but expected %s",
1206 update->refname,
1207 oid_to_hex(&update->old_oid));
1208 goto error;
1209 }
1210 }
1211
1212 if (cmp < 0) {
1213 /* Pass the old reference through. */
1214
1215 struct object_id peeled;
1216 int peel_error = ref_iterator_peel(iter, &peeled);
1217
1218 if (write_packed_entry(out, iter->refname,
1219 iter->oid->hash,
1220 peel_error ? NULL : peeled.hash))
1221 goto write_error;
1222
1223 if ((ok = ref_iterator_advance(iter)) != ITER_OK)
1224 iter = NULL;
1225 } else if (is_null_oid(&update->new_oid)) {
1226 /*
1227 * The update wants to delete the reference,
1228 * and the reference either didn't exist or we
1229 * have already skipped it. So we're done with
1230 * the update (and don't have to write
1231 * anything).
1232 */
1233 i++;
1234 } else {
1235 struct object_id peeled;
1236 int peel_error = peel_object(update->new_oid.hash,
1237 peeled.hash);
1238
1239 if (write_packed_entry(out, update->refname,
1240 update->new_oid.hash,
1241 peel_error ? NULL : peeled.hash))
1242 goto write_error;
1243
1244 i++;
1245 }
1246 }
1247
1248 if (ok != ITER_DONE) {
1249 strbuf_addf(err, "unable to write packed-refs file: "
1250 "error iterating over old contents");
1251 goto error;
1252 }
1253
1254 if (close_tempfile(&refs->tempfile)) {
1255 strbuf_addf(err, "error closing file %s: %s",
1256 get_tempfile_path(&refs->tempfile),
1257 strerror(errno));
1258 strbuf_release(&sb);
1259 return -1;
1260 }
1261
1262 return 0;
1263
1264 write_error:
1265 strbuf_addf(err, "error writing to %s: %s",
1266 get_tempfile_path(&refs->tempfile), strerror(errno));
1267
1268 error:
1269 if (iter)
1270 ref_iterator_abort(iter);
1271
1272 delete_tempfile(&refs->tempfile);
1273 return -1;
1274 }
1275
1276 struct packed_transaction_backend_data {
1277 /* True iff the transaction owns the packed-refs lock. */
1278 int own_lock;
1279
1280 struct string_list updates;
1281 };
1282
1283 static void packed_transaction_cleanup(struct packed_ref_store *refs,
1284 struct ref_transaction *transaction)
1285 {
1286 struct packed_transaction_backend_data *data = transaction->backend_data;
1287
1288 if (data) {
1289 string_list_clear(&data->updates, 0);
1290
1291 if (is_tempfile_active(&refs->tempfile))
1292 delete_tempfile(&refs->tempfile);
1293
1294 if (data->own_lock && is_lock_file_locked(&refs->lock)) {
1295 packed_refs_unlock(&refs->base);
1296 data->own_lock = 0;
1297 }
1298
1299 free(data);
1300 transaction->backend_data = NULL;
1301 }
1302
1303 transaction->state = REF_TRANSACTION_CLOSED;
1304 }
1305
1306 static int packed_transaction_prepare(struct ref_store *ref_store,
1307 struct ref_transaction *transaction,
1308 struct strbuf *err)
1309 {
1310 struct packed_ref_store *refs = packed_downcast(
1311 ref_store,
1312 REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
1313 "ref_transaction_prepare");
1314 struct packed_transaction_backend_data *data;
1315 size_t i;
1316 int ret = TRANSACTION_GENERIC_ERROR;
1317
1318 /*
1319 * Note that we *don't* skip transactions with zero updates,
1320 * because such a transaction might be executed for the side
1321 * effect of ensuring that all of the references are peeled.
1322 * If the caller wants to optimize away empty transactions, it
1323 * should do so itself.
1324 */
1325
1326 data = xcalloc(1, sizeof(*data));
1327 string_list_init(&data->updates, 0);
1328
1329 transaction->backend_data = data;
1330
1331 /*
1332 * Stick the updates in a string list by refname so that we
1333 * can sort them:
1334 */
1335 for (i = 0; i < transaction->nr; i++) {
1336 struct ref_update *update = transaction->updates[i];
1337 struct string_list_item *item =
1338 string_list_append(&data->updates, update->refname);
1339
1340 /* Store a pointer to update in item->util: */
1341 item->util = update;
1342 }
1343 string_list_sort(&data->updates);
1344
1345 if (ref_update_reject_duplicates(&data->updates, err))
1346 goto failure;
1347
1348 if (!is_lock_file_locked(&refs->lock)) {
1349 if (packed_refs_lock(ref_store, 0, err))
1350 goto failure;
1351 data->own_lock = 1;
1352 }
1353
1354 if (write_with_updates(refs, &data->updates, err))
1355 goto failure;
1356
1357 transaction->state = REF_TRANSACTION_PREPARED;
1358 return 0;
1359
1360 failure:
1361 packed_transaction_cleanup(refs, transaction);
1362 return ret;
1363 }
1364
1365 static int packed_transaction_abort(struct ref_store *ref_store,
1366 struct ref_transaction *transaction,
1367 struct strbuf *err)
1368 {
1369 struct packed_ref_store *refs = packed_downcast(
1370 ref_store,
1371 REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
1372 "ref_transaction_abort");
1373
1374 packed_transaction_cleanup(refs, transaction);
1375 return 0;
1376 }
1377
1378 static int packed_transaction_finish(struct ref_store *ref_store,
1379 struct ref_transaction *transaction,
1380 struct strbuf *err)
1381 {
1382 struct packed_ref_store *refs = packed_downcast(
1383 ref_store,
1384 REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
1385 "ref_transaction_finish");
1386 int ret = TRANSACTION_GENERIC_ERROR;
1387 char *packed_refs_path;
1388
1389 clear_packed_ref_cache(refs);
1390
1391 packed_refs_path = get_locked_file_path(&refs->lock);
1392 if (rename_tempfile(&refs->tempfile, packed_refs_path)) {
1393 strbuf_addf(err, "error replacing %s: %s",
1394 refs->path, strerror(errno));
1395 goto cleanup;
1396 }
1397
1398 ret = 0;
1399
1400 cleanup:
1401 free(packed_refs_path);
1402 packed_transaction_cleanup(refs, transaction);
1403 return ret;
1404 }
1405
1406 static int packed_initial_transaction_commit(struct ref_store *ref_store,
1407 struct ref_transaction *transaction,
1408 struct strbuf *err)
1409 {
1410 return ref_transaction_commit(transaction, err);
1411 }
1412
1413 static int packed_delete_refs(struct ref_store *ref_store, const char *msg,
1414 struct string_list *refnames, unsigned int flags)
1415 {
1416 struct packed_ref_store *refs =
1417 packed_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
1418 struct strbuf err = STRBUF_INIT;
1419 struct ref_transaction *transaction;
1420 struct string_list_item *item;
1421 int ret;
1422
1423 (void)refs; /* We need the check above, but don't use the variable */
1424
1425 if (!refnames->nr)
1426 return 0;
1427
1428 /*
1429 * Since we don't check the references' old_oids, the
1430 * individual updates can't fail, so we can pack all of the
1431 * updates into a single transaction.
1432 */
1433
1434 transaction = ref_store_transaction_begin(ref_store, &err);
1435 if (!transaction)
1436 return -1;
1437
1438 for_each_string_list_item(item, refnames) {
1439 if (ref_transaction_delete(transaction, item->string, NULL,
1440 flags, msg, &err)) {
1441 warning(_("could not delete reference %s: %s"),
1442 item->string, err.buf);
1443 strbuf_reset(&err);
1444 }
1445 }
1446
1447 ret = ref_transaction_commit(transaction, &err);
1448
1449 if (ret) {
1450 if (refnames->nr == 1)
1451 error(_("could not delete reference %s: %s"),
1452 refnames->items[0].string, err.buf);
1453 else
1454 error(_("could not delete references: %s"), err.buf);
1455 }
1456
1457 ref_transaction_free(transaction);
1458 strbuf_release(&err);
1459 return ret;
1460 }
1461
1462 static int packed_pack_refs(struct ref_store *ref_store, unsigned int flags)
1463 {
1464 /*
1465 * Packed refs are already packed. It might be that loose refs
1466 * are packed *into* a packed refs store, but that is done by
1467 * updating the packed references via a transaction.
1468 */
1469 return 0;
1470 }
1471
1472 static int packed_create_symref(struct ref_store *ref_store,
1473 const char *refname, const char *target,
1474 const char *logmsg)
1475 {
1476 die("BUG: packed reference store does not support symrefs");
1477 }
1478
1479 static int packed_rename_ref(struct ref_store *ref_store,
1480 const char *oldrefname, const char *newrefname,
1481 const char *logmsg)
1482 {
1483 die("BUG: packed reference store does not support renaming references");
1484 }
1485
1486 static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store)
1487 {
1488 return empty_ref_iterator_begin();
1489 }
1490
1491 static int packed_for_each_reflog_ent(struct ref_store *ref_store,
1492 const char *refname,
1493 each_reflog_ent_fn fn, void *cb_data)
1494 {
1495 return 0;
1496 }
1497
1498 static int packed_for_each_reflog_ent_reverse(struct ref_store *ref_store,
1499 const char *refname,
1500 each_reflog_ent_fn fn,
1501 void *cb_data)
1502 {
1503 return 0;
1504 }
1505
1506 static int packed_reflog_exists(struct ref_store *ref_store,
1507 const char *refname)
1508 {
1509 return 0;
1510 }
1511
1512 static int packed_create_reflog(struct ref_store *ref_store,
1513 const char *refname, int force_create,
1514 struct strbuf *err)
1515 {
1516 die("BUG: packed reference store does not support reflogs");
1517 }
1518
1519 static int packed_delete_reflog(struct ref_store *ref_store,
1520 const char *refname)
1521 {
1522 return 0;
1523 }
1524
1525 static int packed_reflog_expire(struct ref_store *ref_store,
1526 const char *refname, const unsigned char *sha1,
1527 unsigned int flags,
1528 reflog_expiry_prepare_fn prepare_fn,
1529 reflog_expiry_should_prune_fn should_prune_fn,
1530 reflog_expiry_cleanup_fn cleanup_fn,
1531 void *policy_cb_data)
1532 {
1533 return 0;
1534 }
1535
1536 struct ref_storage_be refs_be_packed = {
1537 NULL,
1538 "packed",
1539 packed_ref_store_create,
1540 packed_init_db,
1541 packed_transaction_prepare,
1542 packed_transaction_finish,
1543 packed_transaction_abort,
1544 packed_initial_transaction_commit,
1545
1546 packed_pack_refs,
1547 packed_create_symref,
1548 packed_delete_refs,
1549 packed_rename_ref,
1550
1551 packed_ref_iterator_begin,
1552 packed_read_raw_ref,
1553
1554 packed_reflog_iterator_begin,
1555 packed_for_each_reflog_ent,
1556 packed_for_each_reflog_ent_reverse,
1557 packed_reflog_exists,
1558 packed_create_reflog,
1559 packed_delete_reflog,
1560 packed_reflog_expire
1561 };