struct ref_transaction: add a place for backends to store data
[git/git.git] / refs / packed-backend.c
CommitLineData
67be7c5a 1#include "../cache.h"
44c2339e 2#include "../config.h"
67be7c5a
MH
3#include "../refs.h"
4#include "refs-internal.h"
5#include "ref-cache.h"
6#include "packed-backend.h"
7#include "../iterator.h"
8#include "../lockfile.h"
9
10struct packed_ref_cache {
11 struct ref_cache *cache;
12
13 /*
14 * Count of references to the data structure in this instance,
15 * including the pointer from files_ref_store::packed if any.
16 * The data will not be freed as long as the reference count
17 * is nonzero.
18 */
19 unsigned int referrers;
20
21 /* The metadata from when this packed-refs cache was read */
22 struct stat_validity validity;
23};
24
25/*
26 * Increment the reference count of *packed_refs.
27 */
28static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
29{
30 packed_refs->referrers++;
31}
32
33/*
34 * Decrease the reference count of *packed_refs. If it goes to zero,
35 * free *packed_refs and return true; otherwise return false.
36 */
37static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
38{
39 if (!--packed_refs->referrers) {
40 free_ref_cache(packed_refs->cache);
41 stat_validity_clear(&packed_refs->validity);
42 free(packed_refs);
43 return 1;
44 } else {
45 return 0;
46 }
47}
48
49/*
50 * A container for `packed-refs`-related data. It is not (yet) a
51 * `ref_store`.
52 */
53struct packed_ref_store {
e0cc8ac8
MH
54 struct ref_store base;
55
67be7c5a
MH
56 unsigned int store_flags;
57
58 /* The path of the "packed-refs" file: */
59 char *path;
60
61 /*
62 * A cache of the values read from the `packed-refs` file, if
63 * it might still be current; otherwise, NULL.
64 */
65 struct packed_ref_cache *cache;
66
67 /*
68 * Lock used for the "packed-refs" file. Note that this (and
69 * thus the enclosing `packed_ref_store`) must not be freed.
70 */
71 struct lock_file lock;
42dfa7ec
MH
72
73 /*
74 * Temporary file used when rewriting new contents to the
75 * "packed-refs" file. Note that this (and thus the enclosing
76 * `packed_ref_store`) must not be freed.
77 */
78 struct tempfile tempfile;
67be7c5a
MH
79};
80
e0cc8ac8
MH
81struct ref_store *packed_ref_store_create(const char *path,
82 unsigned int store_flags)
67be7c5a
MH
83{
84 struct packed_ref_store *refs = xcalloc(1, sizeof(*refs));
e0cc8ac8 85 struct ref_store *ref_store = (struct ref_store *)refs;
67be7c5a 86
e0cc8ac8 87 base_ref_store_init(ref_store, &refs_be_packed);
67be7c5a 88 refs->store_flags = store_flags;
e0cc8ac8 89
67be7c5a 90 refs->path = xstrdup(path);
e0cc8ac8 91 return ref_store;
67be7c5a
MH
92}
93
94/*
95 * Die if refs is not the main ref store. caller is used in any
96 * necessary error messages.
97 */
98static void packed_assert_main_repository(struct packed_ref_store *refs,
99 const char *caller)
100{
101 if (refs->store_flags & REF_STORE_MAIN)
102 return;
103
104 die("BUG: operation %s only allowed for main ref store", caller);
105}
106
e0cc8ac8
MH
107/*
108 * Downcast `ref_store` to `packed_ref_store`. Die if `ref_store` is
109 * not a `packed_ref_store`. Also die if `packed_ref_store` doesn't
110 * support at least the flags specified in `required_flags`. `caller`
111 * is used in any necessary error messages.
112 */
113static struct packed_ref_store *packed_downcast(struct ref_store *ref_store,
114 unsigned int required_flags,
115 const char *caller)
116{
117 struct packed_ref_store *refs;
118
119 if (ref_store->be != &refs_be_packed)
120 die("BUG: ref_store is type \"%s\" not \"packed\" in %s",
121 ref_store->be->name, caller);
122
123 refs = (struct packed_ref_store *)ref_store;
124
125 if ((refs->store_flags & required_flags) != required_flags)
126 die("BUG: unallowed operation (%s), requires %x, has %x\n",
127 caller, required_flags, refs->store_flags);
128
129 return refs;
130}
131
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MH
132static void clear_packed_ref_cache(struct packed_ref_store *refs)
133{
134 if (refs->cache) {
135 struct packed_ref_cache *cache = refs->cache;
136
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MH
137 refs->cache = NULL;
138 release_packed_ref_cache(cache);
139 }
140}
141
142/* The length of a peeled reference line in packed-refs, including EOL: */
143#define PEELED_LINE_LENGTH 42
144
145/*
146 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
147 * Return a pointer to the refname within the line (null-terminated),
148 * or NULL if there was a problem.
149 */
150static const char *parse_ref_line(struct strbuf *line, struct object_id *oid)
151{
152 const char *ref;
153
154 if (parse_oid_hex(line->buf, oid, &ref) < 0)
155 return NULL;
156 if (!isspace(*ref++))
157 return NULL;
158
159 if (isspace(*ref))
160 return NULL;
161
162 if (line->buf[line->len - 1] != '\n')
163 return NULL;
164 line->buf[--line->len] = 0;
165
166 return ref;
167}
168
169/*
170 * Read from `packed_refs_file` into a newly-allocated
171 * `packed_ref_cache` and return it. The return value will already
172 * have its reference count incremented.
173 *
174 * A comment line of the form "# pack-refs with: " may contain zero or
175 * more traits. We interpret the traits as follows:
176 *
177 * No traits:
178 *
179 * Probably no references are peeled. But if the file contains a
180 * peeled value for a reference, we will use it.
181 *
182 * peeled:
183 *
184 * References under "refs/tags/", if they *can* be peeled, *are*
185 * peeled in this file. References outside of "refs/tags/" are
186 * probably not peeled even if they could have been, but if we find
187 * a peeled value for such a reference we will use it.
188 *
189 * fully-peeled:
190 *
191 * All references in the file that can be peeled are peeled.
192 * Inversely (and this is more important), any references in the
193 * file for which no peeled value is recorded is not peelable. This
194 * trait should typically be written alongside "peeled" for
195 * compatibility with older clients, but we do not require it
196 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
197 */
198static struct packed_ref_cache *read_packed_refs(const char *packed_refs_file)
199{
200 FILE *f;
201 struct packed_ref_cache *packed_refs = xcalloc(1, sizeof(*packed_refs));
202 struct ref_entry *last = NULL;
203 struct strbuf line = STRBUF_INIT;
204 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
205 struct ref_dir *dir;
206
207 acquire_packed_ref_cache(packed_refs);
208 packed_refs->cache = create_ref_cache(NULL, NULL);
209 packed_refs->cache->root->flag &= ~REF_INCOMPLETE;
210
211 f = fopen(packed_refs_file, "r");
212 if (!f) {
213 if (errno == ENOENT) {
214 /*
215 * This is OK; it just means that no
216 * "packed-refs" file has been written yet,
217 * which is equivalent to it being empty.
218 */
219 return packed_refs;
220 } else {
221 die_errno("couldn't read %s", packed_refs_file);
222 }
223 }
224
225 stat_validity_update(&packed_refs->validity, fileno(f));
226
227 dir = get_ref_dir(packed_refs->cache->root);
228 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
229 struct object_id oid;
230 const char *refname;
231 const char *traits;
232
9308b7f3
MH
233 if (!line.len || line.buf[line.len - 1] != '\n')
234 die("unterminated line in %s: %s", packed_refs_file, line.buf);
235
67be7c5a
MH
236 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
237 if (strstr(traits, " fully-peeled "))
238 peeled = PEELED_FULLY;
239 else if (strstr(traits, " peeled "))
240 peeled = PEELED_TAGS;
241 /* perhaps other traits later as well */
242 continue;
243 }
244
245 refname = parse_ref_line(&line, &oid);
246 if (refname) {
247 int flag = REF_ISPACKED;
248
249 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
250 if (!refname_is_safe(refname))
251 die("packed refname is dangerous: %s", refname);
252 oidclr(&oid);
253 flag |= REF_BAD_NAME | REF_ISBROKEN;
254 }
255 last = create_ref_entry(refname, &oid, flag);
256 if (peeled == PEELED_FULLY ||
257 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
258 last->flag |= REF_KNOWS_PEELED;
259 add_ref_entry(dir, last);
9308b7f3 260 } else if (last &&
67be7c5a
MH
261 line.buf[0] == '^' &&
262 line.len == PEELED_LINE_LENGTH &&
263 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
264 !get_oid_hex(line.buf + 1, &oid)) {
265 oidcpy(&last->u.value.peeled, &oid);
266 /*
267 * Regardless of what the file header said,
268 * we definitely know the value of *this*
269 * reference:
270 */
271 last->flag |= REF_KNOWS_PEELED;
9308b7f3
MH
272 } else {
273 strbuf_setlen(&line, line.len - 1);
274 die("unexpected line in %s: %s", packed_refs_file, line.buf);
67be7c5a
MH
275 }
276 }
277
278 fclose(f);
279 strbuf_release(&line);
280
281 return packed_refs;
282}
283
284/*
285 * Check that the packed refs cache (if any) still reflects the
286 * contents of the file. If not, clear the cache.
287 */
288static void validate_packed_ref_cache(struct packed_ref_store *refs)
289{
290 if (refs->cache &&
291 !stat_validity_check(&refs->cache->validity, refs->path))
292 clear_packed_ref_cache(refs);
293}
294
295/*
296 * Get the packed_ref_cache for the specified packed_ref_store,
297 * creating and populating it if it hasn't been read before or if the
298 * file has been changed (according to its `validity` field) since it
299 * was last read. On the other hand, if we hold the lock, then assume
300 * that the file hasn't been changed out from under us, so skip the
301 * extra `stat()` call in `stat_validity_check()`.
302 */
303static struct packed_ref_cache *get_packed_ref_cache(struct packed_ref_store *refs)
304{
305 if (!is_lock_file_locked(&refs->lock))
306 validate_packed_ref_cache(refs);
307
308 if (!refs->cache)
309 refs->cache = read_packed_refs(refs->path);
310
311 return refs->cache;
312}
313
314static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
315{
316 return get_ref_dir(packed_ref_cache->cache->root);
317}
318
319static struct ref_dir *get_packed_refs(struct packed_ref_store *refs)
320{
321 return get_packed_ref_dir(get_packed_ref_cache(refs));
322}
323
324/*
325 * Add or overwrite a reference in the in-memory packed reference
326 * cache. This may only be called while the packed-refs file is locked
b7de57d8 327 * (see packed_refs_lock()). To actually write the packed-refs file,
67be7c5a
MH
328 * call commit_packed_refs().
329 */
e0cc8ac8 330void add_packed_ref(struct ref_store *ref_store,
67be7c5a
MH
331 const char *refname, const struct object_id *oid)
332{
e0cc8ac8
MH
333 struct packed_ref_store *refs =
334 packed_downcast(ref_store, REF_STORE_WRITE,
335 "add_packed_ref");
67be7c5a
MH
336 struct ref_dir *packed_refs;
337 struct ref_entry *packed_entry;
338
339 if (!is_lock_file_locked(&refs->lock))
340 die("BUG: packed refs not locked");
341
342 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
343 die("Reference has invalid format: '%s'", refname);
344
345 packed_refs = get_packed_refs(refs);
346 packed_entry = find_ref_entry(packed_refs, refname);
347 if (packed_entry) {
348 /* Overwrite the existing entry: */
349 oidcpy(&packed_entry->u.value.oid, oid);
350 packed_entry->flag = REF_ISPACKED;
351 oidclr(&packed_entry->u.value.peeled);
352 } else {
353 packed_entry = create_ref_entry(refname, oid, REF_ISPACKED);
354 add_ref_entry(packed_refs, packed_entry);
355 }
356}
357
358/*
359 * Return the ref_entry for the given refname from the packed
360 * references. If it does not exist, return NULL.
361 */
362static struct ref_entry *get_packed_ref(struct packed_ref_store *refs,
363 const char *refname)
364{
365 return find_ref_entry(get_packed_refs(refs), refname);
366}
367
e0cc8ac8
MH
368static int packed_read_raw_ref(struct ref_store *ref_store,
369 const char *refname, unsigned char *sha1,
370 struct strbuf *referent, unsigned int *type)
67be7c5a 371{
e0cc8ac8
MH
372 struct packed_ref_store *refs =
373 packed_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
374
67be7c5a
MH
375 struct ref_entry *entry;
376
377 *type = 0;
378
379 entry = get_packed_ref(refs, refname);
380 if (!entry) {
381 errno = ENOENT;
382 return -1;
383 }
384
385 hashcpy(sha1, entry->u.value.oid.hash);
386 *type = REF_ISPACKED;
387 return 0;
388}
389
e0cc8ac8
MH
390static int packed_peel_ref(struct ref_store *ref_store,
391 const char *refname, unsigned char *sha1)
67be7c5a 392{
e0cc8ac8
MH
393 struct packed_ref_store *refs =
394 packed_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
395 "peel_ref");
67be7c5a
MH
396 struct ref_entry *r = get_packed_ref(refs, refname);
397
398 if (!r || peel_entry(r, 0))
399 return -1;
400
401 hashcpy(sha1, r->u.value.peeled.hash);
402 return 0;
403}
404
405struct packed_ref_iterator {
406 struct ref_iterator base;
407
408 struct packed_ref_cache *cache;
409 struct ref_iterator *iter0;
410 unsigned int flags;
411};
412
413static int packed_ref_iterator_advance(struct ref_iterator *ref_iterator)
414{
415 struct packed_ref_iterator *iter =
416 (struct packed_ref_iterator *)ref_iterator;
417 int ok;
418
419 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
420 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
421 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
422 continue;
423
424 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
425 !ref_resolves_to_object(iter->iter0->refname,
426 iter->iter0->oid,
427 iter->iter0->flags))
428 continue;
429
430 iter->base.refname = iter->iter0->refname;
431 iter->base.oid = iter->iter0->oid;
432 iter->base.flags = iter->iter0->flags;
433 return ITER_OK;
434 }
435
436 iter->iter0 = NULL;
437 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
438 ok = ITER_ERROR;
439
440 return ok;
441}
442
443static int packed_ref_iterator_peel(struct ref_iterator *ref_iterator,
444 struct object_id *peeled)
445{
446 struct packed_ref_iterator *iter =
447 (struct packed_ref_iterator *)ref_iterator;
448
449 return ref_iterator_peel(iter->iter0, peeled);
450}
451
452static int packed_ref_iterator_abort(struct ref_iterator *ref_iterator)
453{
454 struct packed_ref_iterator *iter =
455 (struct packed_ref_iterator *)ref_iterator;
456 int ok = ITER_DONE;
457
458 if (iter->iter0)
459 ok = ref_iterator_abort(iter->iter0);
460
461 release_packed_ref_cache(iter->cache);
462 base_ref_iterator_free(ref_iterator);
463 return ok;
464}
465
466static struct ref_iterator_vtable packed_ref_iterator_vtable = {
467 packed_ref_iterator_advance,
468 packed_ref_iterator_peel,
469 packed_ref_iterator_abort
470};
471
e0cc8ac8
MH
472static struct ref_iterator *packed_ref_iterator_begin(
473 struct ref_store *ref_store,
67be7c5a
MH
474 const char *prefix, unsigned int flags)
475{
e0cc8ac8 476 struct packed_ref_store *refs;
67be7c5a
MH
477 struct packed_ref_iterator *iter;
478 struct ref_iterator *ref_iterator;
e0cc8ac8
MH
479 unsigned int required_flags = REF_STORE_READ;
480
481 if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
482 required_flags |= REF_STORE_ODB;
483 refs = packed_downcast(ref_store, required_flags, "ref_iterator_begin");
67be7c5a
MH
484
485 iter = xcalloc(1, sizeof(*iter));
486 ref_iterator = &iter->base;
487 base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable);
488
489 /*
490 * Note that get_packed_ref_cache() internally checks whether
491 * the packed-ref cache is up to date with what is on disk,
492 * and re-reads it if not.
493 */
494
495 iter->cache = get_packed_ref_cache(refs);
496 acquire_packed_ref_cache(iter->cache);
497 iter->iter0 = cache_ref_iterator_begin(iter->cache->cache, prefix, 0);
498
499 iter->flags = flags;
500
501 return ref_iterator;
502}
503
504/*
505 * Write an entry to the packed-refs file for the specified refname.
3478983b
MH
506 * If peeled is non-NULL, write it as the entry's peeled value. On
507 * error, return a nonzero value and leave errno set at the value left
508 * by the failing call to `fprintf()`.
67be7c5a 509 */
3478983b
MH
510static int write_packed_entry(FILE *fh, const char *refname,
511 const unsigned char *sha1,
512 const unsigned char *peeled)
67be7c5a 513{
3478983b
MH
514 if (fprintf(fh, "%s %s\n", sha1_to_hex(sha1), refname) < 0 ||
515 (peeled && fprintf(fh, "^%s\n", sha1_to_hex(peeled)) < 0))
516 return -1;
517
518 return 0;
67be7c5a
MH
519}
520
c8bed835 521int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
67be7c5a 522{
e0cc8ac8
MH
523 struct packed_ref_store *refs =
524 packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
b7de57d8 525 "packed_refs_lock");
67be7c5a
MH
526 static int timeout_configured = 0;
527 static int timeout_value = 1000;
67be7c5a 528
67be7c5a
MH
529 if (!timeout_configured) {
530 git_config_get_int("core.packedrefstimeout", &timeout_value);
531 timeout_configured = 1;
532 }
533
42dfa7ec
MH
534 /*
535 * Note that we close the lockfile immediately because we
536 * don't write new content to it, but rather to a separate
537 * tempfile.
538 */
67be7c5a
MH
539 if (hold_lock_file_for_update_timeout(
540 &refs->lock,
541 refs->path,
c8bed835
MH
542 flags, timeout_value) < 0) {
543 unable_to_lock_message(refs->path, errno, err);
544 return -1;
545 }
546
547 if (close_lock_file(&refs->lock)) {
548 strbuf_addf(err, "unable to close %s: %s", refs->path, strerror(errno));
67be7c5a 549 return -1;
c8bed835 550 }
67be7c5a
MH
551
552 /*
553 * Now that we hold the `packed-refs` lock, make sure that our
554 * cache matches the current version of the file. Normally
555 * `get_packed_ref_cache()` does that for us, but that
556 * function assumes that when the file is locked, any existing
557 * cache is still valid. We've just locked the file, but it
558 * might have changed the moment *before* we locked it.
559 */
560 validate_packed_ref_cache(refs);
561
39c8df0c
MH
562 /*
563 * Now make sure that the packed-refs file as it exists in the
564 * locked state is loaded into the cache:
565 */
566 get_packed_ref_cache(refs);
67be7c5a
MH
567 return 0;
568}
569
49aebcf4
MH
570void packed_refs_unlock(struct ref_store *ref_store)
571{
572 struct packed_ref_store *refs = packed_downcast(
573 ref_store,
574 REF_STORE_READ | REF_STORE_WRITE,
575 "packed_refs_unlock");
576
577 if (!is_lock_file_locked(&refs->lock))
578 die("BUG: packed_refs_unlock() called when not locked");
579 rollback_lock_file(&refs->lock);
49aebcf4
MH
580}
581
582int packed_refs_is_locked(struct ref_store *ref_store)
583{
584 struct packed_ref_store *refs = packed_downcast(
585 ref_store,
586 REF_STORE_READ | REF_STORE_WRITE,
587 "packed_refs_is_locked");
588
589 return is_lock_file_locked(&refs->lock);
590}
591
67be7c5a
MH
592/*
593 * The packed-refs header line that we write out. Perhaps other
594 * traits will be added later. The trailing space is required.
595 */
596static const char PACKED_REFS_HEADER[] =
597 "# pack-refs with: peeled fully-peeled \n";
598
599/*
600 * Write the current version of the packed refs cache from memory to
601 * disk. The packed-refs file must already be locked for writing (see
b7de57d8 602 * packed_refs_lock()). Return zero on success. On errors, rollback
3478983b
MH
603 * the lockfile, write an error message to `err`, and return a nonzero
604 * value.
67be7c5a 605 */
3478983b 606int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err)
67be7c5a 607{
e0cc8ac8
MH
608 struct packed_ref_store *refs =
609 packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
610 "commit_packed_refs");
67be7c5a
MH
611 struct packed_ref_cache *packed_ref_cache =
612 get_packed_ref_cache(refs);
3478983b 613 int ok;
198b808e 614 int ret = -1;
42dfa7ec 615 struct strbuf sb = STRBUF_INIT;
67be7c5a
MH
616 FILE *out;
617 struct ref_iterator *iter;
198b808e 618 char *packed_refs_path;
67be7c5a 619
67be7c5a 620 if (!is_lock_file_locked(&refs->lock))
3478983b 621 die("BUG: commit_packed_refs() called when unlocked");
67be7c5a 622
198b808e
MH
623 /*
624 * If packed-refs is a symlink, we want to overwrite the
625 * symlinked-to file, not the symlink itself. Also, put the
626 * staging file next to it:
627 */
628 packed_refs_path = get_locked_file_path(&refs->lock);
629 strbuf_addf(&sb, "%s.new", packed_refs_path);
42dfa7ec
MH
630 if (create_tempfile(&refs->tempfile, sb.buf) < 0) {
631 strbuf_addf(err, "unable to create file %s: %s",
632 sb.buf, strerror(errno));
633 strbuf_release(&sb);
198b808e 634 goto out;
42dfa7ec
MH
635 }
636 strbuf_release(&sb);
637
638 out = fdopen_tempfile(&refs->tempfile, "w");
3478983b
MH
639 if (!out) {
640 strbuf_addf(err, "unable to fdopen packed-refs tempfile: %s",
641 strerror(errno));
642 goto error;
643 }
67be7c5a 644
3478983b
MH
645 if (fprintf(out, "%s", PACKED_REFS_HEADER) < 0) {
646 strbuf_addf(err, "error writing to %s: %s",
42dfa7ec 647 get_tempfile_path(&refs->tempfile), strerror(errno));
3478983b
MH
648 goto error;
649 }
67be7c5a
MH
650
651 iter = cache_ref_iterator_begin(packed_ref_cache->cache, NULL, 0);
652 while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
653 struct object_id peeled;
654 int peel_error = ref_iterator_peel(iter, &peeled);
655
3478983b
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656 if (write_packed_entry(out, iter->refname, iter->oid->hash,
657 peel_error ? NULL : peeled.hash)) {
658 strbuf_addf(err, "error writing to %s: %s",
42dfa7ec 659 get_tempfile_path(&refs->tempfile),
3478983b
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660 strerror(errno));
661 ref_iterator_abort(iter);
662 goto error;
663 }
67be7c5a
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664 }
665
3478983b 666 if (ok != ITER_DONE) {
42dfa7ec 667 strbuf_addf(err, "unable to rewrite packed-refs file: "
3478983b
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668 "error iterating over old contents");
669 goto error;
670 }
67be7c5a 671
198b808e 672 if (rename_tempfile(&refs->tempfile, packed_refs_path)) {
42dfa7ec 673 strbuf_addf(err, "error replacing %s: %s",
3478983b 674 refs->path, strerror(errno));
198b808e 675 goto out;
67be7c5a 676 }
3478983b 677
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678 ret = 0;
679 goto out;
3478983b
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680
681error:
42dfa7ec 682 delete_tempfile(&refs->tempfile);
198b808e
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683
684out:
685 free(packed_refs_path);
686 return ret;
67be7c5a
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687}
688
67be7c5a
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689/*
690 * Rewrite the packed-refs file, omitting any refs listed in
691 * 'refnames'. On error, leave packed-refs unchanged, write an error
e5cc7d7d
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692 * message to 'err', and return a nonzero value. The packed refs lock
693 * must be held when calling this function; it will still be held when
694 * the function returns.
67be7c5a
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695 *
696 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
697 */
e0cc8ac8 698int repack_without_refs(struct ref_store *ref_store,
67be7c5a
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699 struct string_list *refnames, struct strbuf *err)
700{
e0cc8ac8
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701 struct packed_ref_store *refs =
702 packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
703 "repack_without_refs");
67be7c5a
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704 struct ref_dir *packed;
705 struct string_list_item *refname;
3478983b 706 int needs_repacking = 0, removed = 0;
67be7c5a
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707
708 packed_assert_main_repository(refs, "repack_without_refs");
709 assert(err);
710
e5cc7d7d
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711 if (!is_lock_file_locked(&refs->lock))
712 die("BUG: repack_without_refs called without holding lock");
713
67be7c5a
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714 /* Look for a packed ref */
715 for_each_string_list_item(refname, refnames) {
716 if (get_packed_ref(refs, refname->string)) {
717 needs_repacking = 1;
718 break;
719 }
720 }
721
722 /* Avoid locking if we have nothing to do */
723 if (!needs_repacking)
724 return 0; /* no refname exists in packed refs */
725
67be7c5a
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726 packed = get_packed_refs(refs);
727
728 /* Remove refnames from the cache */
729 for_each_string_list_item(refname, refnames)
730 if (remove_entry_from_dir(packed, refname->string) != -1)
731 removed = 1;
732 if (!removed) {
733 /*
734 * All packed entries disappeared while we were
735 * acquiring the lock.
736 */
e5cc7d7d 737 clear_packed_ref_cache(refs);
67be7c5a
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738 return 0;
739 }
740
741 /* Write what remains */
e5cc7d7d 742 return commit_packed_refs(&refs->base, err);
67be7c5a 743}
e0cc8ac8
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744
745static int packed_init_db(struct ref_store *ref_store, struct strbuf *err)
746{
747 /* Nothing to do. */
748 return 0;
749}
750
751static int packed_transaction_prepare(struct ref_store *ref_store,
752 struct ref_transaction *transaction,
753 struct strbuf *err)
754{
755 die("BUG: not implemented yet");
756}
757
758static int packed_transaction_abort(struct ref_store *ref_store,
759 struct ref_transaction *transaction,
760 struct strbuf *err)
761{
762 die("BUG: not implemented yet");
763}
764
765static int packed_transaction_finish(struct ref_store *ref_store,
766 struct ref_transaction *transaction,
767 struct strbuf *err)
768{
769 die("BUG: not implemented yet");
770}
771
772static int packed_initial_transaction_commit(struct ref_store *ref_store,
773 struct ref_transaction *transaction,
774 struct strbuf *err)
775{
776 return ref_transaction_commit(transaction, err);
777}
778
779static int packed_delete_refs(struct ref_store *ref_store, const char *msg,
780 struct string_list *refnames, unsigned int flags)
781{
782 die("BUG: not implemented yet");
783}
784
785static int packed_pack_refs(struct ref_store *ref_store, unsigned int flags)
786{
787 /*
788 * Packed refs are already packed. It might be that loose refs
789 * are packed *into* a packed refs store, but that is done by
790 * updating the packed references via a transaction.
791 */
792 return 0;
793}
794
795static int packed_create_symref(struct ref_store *ref_store,
796 const char *refname, const char *target,
797 const char *logmsg)
798{
799 die("BUG: packed reference store does not support symrefs");
800}
801
802static int packed_rename_ref(struct ref_store *ref_store,
803 const char *oldrefname, const char *newrefname,
804 const char *logmsg)
805{
806 die("BUG: packed reference store does not support renaming references");
807}
808
809static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store)
810{
811 return empty_ref_iterator_begin();
812}
813
814static int packed_for_each_reflog_ent(struct ref_store *ref_store,
815 const char *refname,
816 each_reflog_ent_fn fn, void *cb_data)
817{
818 return 0;
819}
820
821static int packed_for_each_reflog_ent_reverse(struct ref_store *ref_store,
822 const char *refname,
823 each_reflog_ent_fn fn,
824 void *cb_data)
825{
826 return 0;
827}
828
829static int packed_reflog_exists(struct ref_store *ref_store,
830 const char *refname)
831{
832 return 0;
833}
834
835static int packed_create_reflog(struct ref_store *ref_store,
836 const char *refname, int force_create,
837 struct strbuf *err)
838{
839 die("BUG: packed reference store does not support reflogs");
840}
841
842static int packed_delete_reflog(struct ref_store *ref_store,
843 const char *refname)
844{
845 return 0;
846}
847
848static int packed_reflog_expire(struct ref_store *ref_store,
849 const char *refname, const unsigned char *sha1,
850 unsigned int flags,
851 reflog_expiry_prepare_fn prepare_fn,
852 reflog_expiry_should_prune_fn should_prune_fn,
853 reflog_expiry_cleanup_fn cleanup_fn,
854 void *policy_cb_data)
855{
856 return 0;
857}
858
859struct ref_storage_be refs_be_packed = {
860 NULL,
861 "packed",
862 packed_ref_store_create,
863 packed_init_db,
864 packed_transaction_prepare,
865 packed_transaction_finish,
866 packed_transaction_abort,
867 packed_initial_transaction_commit,
868
869 packed_pack_refs,
870 packed_peel_ref,
871 packed_create_symref,
872 packed_delete_refs,
873 packed_rename_ref,
874
875 packed_ref_iterator_begin,
876 packed_read_raw_ref,
877
878 packed_reflog_iterator_begin,
879 packed_for_each_reflog_ent,
880 packed_for_each_reflog_ent_reverse,
881 packed_reflog_exists,
882 packed_create_reflog,
883 packed_delete_reflog,
884 packed_reflog_expire
885};