refs: rename get_ref_store() to get_submodule_ref_store() and make it public
[git/git.git] / refs / files-backend.c
CommitLineData
7bd9bcf3
MH
1#include "../cache.h"
2#include "../refs.h"
3#include "refs-internal.h"
3bc581b9 4#include "../iterator.h"
2880d16f 5#include "../dir-iterator.h"
7bd9bcf3
MH
6#include "../lockfile.h"
7#include "../object.h"
8#include "../dir.h"
9
10struct ref_lock {
11 char *ref_name;
7bd9bcf3
MH
12 struct lock_file *lk;
13 struct object_id old_oid;
14};
15
16struct ref_entry;
17
18/*
19 * Information used (along with the information in ref_entry) to
20 * describe a single cached reference. This data structure only
21 * occurs embedded in a union in struct ref_entry, and only when
22 * (ref_entry->flag & REF_DIR) is zero.
23 */
24struct ref_value {
25 /*
26 * The name of the object to which this reference resolves
27 * (which may be a tag object). If REF_ISBROKEN, this is
28 * null. If REF_ISSYMREF, then this is the name of the object
29 * referred to by the last reference in the symlink chain.
30 */
31 struct object_id oid;
32
33 /*
34 * If REF_KNOWS_PEELED, then this field holds the peeled value
35 * of this reference, or null if the reference is known not to
36 * be peelable. See the documentation for peel_ref() for an
37 * exact definition of "peelable".
38 */
39 struct object_id peeled;
40};
41
65a0a8e5 42struct files_ref_store;
7bd9bcf3
MH
43
44/*
45 * Information used (along with the information in ref_entry) to
46 * describe a level in the hierarchy of references. This data
47 * structure only occurs embedded in a union in struct ref_entry, and
48 * only when (ref_entry.flag & REF_DIR) is set. In that case,
49 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
50 * in the directory have already been read:
51 *
52 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
53 * or packed references, already read.
54 *
55 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
56 * references that hasn't been read yet (nor has any of its
57 * subdirectories).
58 *
59 * Entries within a directory are stored within a growable array of
60 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
61 * sorted are sorted by their component name in strcmp() order and the
62 * remaining entries are unsorted.
63 *
64 * Loose references are read lazily, one directory at a time. When a
65 * directory of loose references is read, then all of the references
66 * in that directory are stored, and REF_INCOMPLETE stubs are created
67 * for any subdirectories, but the subdirectories themselves are not
68 * read. The reading is triggered by get_ref_dir().
69 */
70struct ref_dir {
71 int nr, alloc;
72
73 /*
74 * Entries with index 0 <= i < sorted are sorted by name. New
75 * entries are appended to the list unsorted, and are sorted
76 * only when required; thus we avoid the need to sort the list
77 * after the addition of every reference.
78 */
79 int sorted;
80
65a0a8e5
MH
81 /* A pointer to the files_ref_store that contains this ref_dir. */
82 struct files_ref_store *ref_store;
7bd9bcf3
MH
83
84 struct ref_entry **entries;
85};
86
87/*
88 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
89 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
90 * public values; see refs.h.
91 */
92
93/*
94 * The field ref_entry->u.value.peeled of this value entry contains
95 * the correct peeled value for the reference, which might be
96 * null_sha1 if the reference is not a tag or if it is broken.
97 */
98#define REF_KNOWS_PEELED 0x10
99
100/* ref_entry represents a directory of references */
101#define REF_DIR 0x20
102
103/*
104 * Entry has not yet been read from disk (used only for REF_DIR
105 * entries representing loose references)
106 */
107#define REF_INCOMPLETE 0x40
108
109/*
110 * A ref_entry represents either a reference or a "subdirectory" of
111 * references.
112 *
113 * Each directory in the reference namespace is represented by a
114 * ref_entry with (flags & REF_DIR) set and containing a subdir member
115 * that holds the entries in that directory that have been read so
116 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
117 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
118 * used for loose reference directories.
119 *
120 * References are represented by a ref_entry with (flags & REF_DIR)
121 * unset and a value member that describes the reference's value. The
122 * flag member is at the ref_entry level, but it is also needed to
123 * interpret the contents of the value field (in other words, a
124 * ref_value object is not very much use without the enclosing
125 * ref_entry).
126 *
127 * Reference names cannot end with slash and directories' names are
128 * always stored with a trailing slash (except for the top-level
129 * directory, which is always denoted by ""). This has two nice
130 * consequences: (1) when the entries in each subdir are sorted
131 * lexicographically by name (as they usually are), the references in
132 * a whole tree can be generated in lexicographic order by traversing
133 * the tree in left-to-right, depth-first order; (2) the names of
134 * references and subdirectories cannot conflict, and therefore the
135 * presence of an empty subdirectory does not block the creation of a
136 * similarly-named reference. (The fact that reference names with the
137 * same leading components can conflict *with each other* is a
138 * separate issue that is regulated by verify_refname_available().)
139 *
140 * Please note that the name field contains the fully-qualified
141 * reference (or subdirectory) name. Space could be saved by only
142 * storing the relative names. But that would require the full names
143 * to be generated on the fly when iterating in do_for_each_ref(), and
144 * would break callback functions, who have always been able to assume
145 * that the name strings that they are passed will not be freed during
146 * the iteration.
147 */
148struct ref_entry {
149 unsigned char flag; /* ISSYMREF? ISPACKED? */
150 union {
151 struct ref_value value; /* if not (flags&REF_DIR) */
152 struct ref_dir subdir; /* if (flags&REF_DIR) */
153 } u;
154 /*
155 * The full name of the reference (e.g., "refs/heads/master")
156 * or the full name of the directory with a trailing slash
157 * (e.g., "refs/heads/"):
158 */
159 char name[FLEX_ARRAY];
160};
161
162static void read_loose_refs(const char *dirname, struct ref_dir *dir);
163static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len);
65a0a8e5 164static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
7bd9bcf3
MH
165 const char *dirname, size_t len,
166 int incomplete);
167static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
802de3da
NTND
168static int files_log_ref_write(struct files_ref_store *refs,
169 const char *refname, const unsigned char *old_sha1,
11f8457f
NTND
170 const unsigned char *new_sha1, const char *msg,
171 int flags, struct strbuf *err);
7bd9bcf3
MH
172
173static struct ref_dir *get_ref_dir(struct ref_entry *entry)
174{
175 struct ref_dir *dir;
176 assert(entry->flag & REF_DIR);
177 dir = &entry->u.subdir;
178 if (entry->flag & REF_INCOMPLETE) {
179 read_loose_refs(entry->name, dir);
180
181 /*
182 * Manually add refs/bisect, which, being
183 * per-worktree, might not appear in the directory
184 * listing for refs/ in the main repo.
185 */
186 if (!strcmp(entry->name, "refs/")) {
187 int pos = search_ref_dir(dir, "refs/bisect/", 12);
188 if (pos < 0) {
189 struct ref_entry *child_entry;
65a0a8e5 190 child_entry = create_dir_entry(dir->ref_store,
7bd9bcf3
MH
191 "refs/bisect/",
192 12, 1);
193 add_entry_to_dir(dir, child_entry);
194 read_loose_refs("refs/bisect",
195 &child_entry->u.subdir);
196 }
197 }
198 entry->flag &= ~REF_INCOMPLETE;
199 }
200 return dir;
201}
202
203static struct ref_entry *create_ref_entry(const char *refname,
204 const unsigned char *sha1, int flag,
205 int check_name)
206{
7bd9bcf3
MH
207 struct ref_entry *ref;
208
209 if (check_name &&
210 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
211 die("Reference has invalid format: '%s'", refname);
96ffc06f 212 FLEX_ALLOC_STR(ref, name, refname);
7bd9bcf3
MH
213 hashcpy(ref->u.value.oid.hash, sha1);
214 oidclr(&ref->u.value.peeled);
7bd9bcf3
MH
215 ref->flag = flag;
216 return ref;
217}
218
219static void clear_ref_dir(struct ref_dir *dir);
220
221static void free_ref_entry(struct ref_entry *entry)
222{
223 if (entry->flag & REF_DIR) {
224 /*
225 * Do not use get_ref_dir() here, as that might
226 * trigger the reading of loose refs.
227 */
228 clear_ref_dir(&entry->u.subdir);
229 }
230 free(entry);
231}
232
233/*
234 * Add a ref_entry to the end of dir (unsorted). Entry is always
235 * stored directly in dir; no recursion into subdirectories is
236 * done.
237 */
238static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
239{
240 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
241 dir->entries[dir->nr++] = entry;
242 /* optimize for the case that entries are added in order */
243 if (dir->nr == 1 ||
244 (dir->nr == dir->sorted + 1 &&
245 strcmp(dir->entries[dir->nr - 2]->name,
246 dir->entries[dir->nr - 1]->name) < 0))
247 dir->sorted = dir->nr;
248}
249
250/*
251 * Clear and free all entries in dir, recursively.
252 */
253static void clear_ref_dir(struct ref_dir *dir)
254{
255 int i;
256 for (i = 0; i < dir->nr; i++)
257 free_ref_entry(dir->entries[i]);
258 free(dir->entries);
259 dir->sorted = dir->nr = dir->alloc = 0;
260 dir->entries = NULL;
261}
262
263/*
264 * Create a struct ref_entry object for the specified dirname.
265 * dirname is the name of the directory with a trailing slash (e.g.,
266 * "refs/heads/") or "" for the top-level directory.
267 */
65a0a8e5 268static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
7bd9bcf3
MH
269 const char *dirname, size_t len,
270 int incomplete)
271{
272 struct ref_entry *direntry;
96ffc06f 273 FLEX_ALLOC_MEM(direntry, name, dirname, len);
65a0a8e5 274 direntry->u.subdir.ref_store = ref_store;
7bd9bcf3
MH
275 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
276 return direntry;
277}
278
279static int ref_entry_cmp(const void *a, const void *b)
280{
281 struct ref_entry *one = *(struct ref_entry **)a;
282 struct ref_entry *two = *(struct ref_entry **)b;
283 return strcmp(one->name, two->name);
284}
285
286static void sort_ref_dir(struct ref_dir *dir);
287
288struct string_slice {
289 size_t len;
290 const char *str;
291};
292
293static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
294{
295 const struct string_slice *key = key_;
296 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
297 int cmp = strncmp(key->str, ent->name, key->len);
298 if (cmp)
299 return cmp;
300 return '\0' - (unsigned char)ent->name[key->len];
301}
302
303/*
304 * Return the index of the entry with the given refname from the
305 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
306 * no such entry is found. dir must already be complete.
307 */
308static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
309{
310 struct ref_entry **r;
311 struct string_slice key;
312
313 if (refname == NULL || !dir->nr)
314 return -1;
315
316 sort_ref_dir(dir);
317 key.len = len;
318 key.str = refname;
319 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
320 ref_entry_cmp_sslice);
321
322 if (r == NULL)
323 return -1;
324
325 return r - dir->entries;
326}
327
328/*
329 * Search for a directory entry directly within dir (without
330 * recursing). Sort dir if necessary. subdirname must be a directory
331 * name (i.e., end in '/'). If mkdir is set, then create the
332 * directory if it is missing; otherwise, return NULL if the desired
333 * directory cannot be found. dir must already be complete.
334 */
335static struct ref_dir *search_for_subdir(struct ref_dir *dir,
336 const char *subdirname, size_t len,
337 int mkdir)
338{
339 int entry_index = search_ref_dir(dir, subdirname, len);
340 struct ref_entry *entry;
341 if (entry_index == -1) {
342 if (!mkdir)
343 return NULL;
344 /*
345 * Since dir is complete, the absence of a subdir
346 * means that the subdir really doesn't exist;
347 * therefore, create an empty record for it but mark
348 * the record complete.
349 */
65a0a8e5 350 entry = create_dir_entry(dir->ref_store, subdirname, len, 0);
7bd9bcf3
MH
351 add_entry_to_dir(dir, entry);
352 } else {
353 entry = dir->entries[entry_index];
354 }
355 return get_ref_dir(entry);
356}
357
358/*
359 * If refname is a reference name, find the ref_dir within the dir
360 * tree that should hold refname. If refname is a directory name
361 * (i.e., ends in '/'), then return that ref_dir itself. dir must
362 * represent the top-level directory and must already be complete.
363 * Sort ref_dirs and recurse into subdirectories as necessary. If
364 * mkdir is set, then create any missing directories; otherwise,
365 * return NULL if the desired directory cannot be found.
366 */
367static struct ref_dir *find_containing_dir(struct ref_dir *dir,
368 const char *refname, int mkdir)
369{
370 const char *slash;
371 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
372 size_t dirnamelen = slash - refname + 1;
373 struct ref_dir *subdir;
374 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
375 if (!subdir) {
376 dir = NULL;
377 break;
378 }
379 dir = subdir;
380 }
381
382 return dir;
383}
384
385/*
386 * Find the value entry with the given name in dir, sorting ref_dirs
387 * and recursing into subdirectories as necessary. If the name is not
388 * found or it corresponds to a directory entry, return NULL.
389 */
390static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
391{
392 int entry_index;
393 struct ref_entry *entry;
394 dir = find_containing_dir(dir, refname, 0);
395 if (!dir)
396 return NULL;
397 entry_index = search_ref_dir(dir, refname, strlen(refname));
398 if (entry_index == -1)
399 return NULL;
400 entry = dir->entries[entry_index];
401 return (entry->flag & REF_DIR) ? NULL : entry;
402}
403
404/*
405 * Remove the entry with the given name from dir, recursing into
406 * subdirectories as necessary. If refname is the name of a directory
407 * (i.e., ends with '/'), then remove the directory and its contents.
408 * If the removal was successful, return the number of entries
409 * remaining in the directory entry that contained the deleted entry.
410 * If the name was not found, return -1. Please note that this
411 * function only deletes the entry from the cache; it does not delete
412 * it from the filesystem or ensure that other cache entries (which
413 * might be symbolic references to the removed entry) are updated.
414 * Nor does it remove any containing dir entries that might be made
415 * empty by the removal. dir must represent the top-level directory
416 * and must already be complete.
417 */
418static int remove_entry(struct ref_dir *dir, const char *refname)
419{
420 int refname_len = strlen(refname);
421 int entry_index;
422 struct ref_entry *entry;
423 int is_dir = refname[refname_len - 1] == '/';
424 if (is_dir) {
425 /*
426 * refname represents a reference directory. Remove
427 * the trailing slash; otherwise we will get the
428 * directory *representing* refname rather than the
429 * one *containing* it.
430 */
431 char *dirname = xmemdupz(refname, refname_len - 1);
432 dir = find_containing_dir(dir, dirname, 0);
433 free(dirname);
434 } else {
435 dir = find_containing_dir(dir, refname, 0);
436 }
437 if (!dir)
438 return -1;
439 entry_index = search_ref_dir(dir, refname, refname_len);
440 if (entry_index == -1)
441 return -1;
442 entry = dir->entries[entry_index];
443
444 memmove(&dir->entries[entry_index],
445 &dir->entries[entry_index + 1],
446 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
447 );
448 dir->nr--;
449 if (dir->sorted > entry_index)
450 dir->sorted--;
451 free_ref_entry(entry);
452 return dir->nr;
453}
454
455/*
456 * Add a ref_entry to the ref_dir (unsorted), recursing into
457 * subdirectories as necessary. dir must represent the top-level
458 * directory. Return 0 on success.
459 */
460static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
461{
462 dir = find_containing_dir(dir, ref->name, 1);
463 if (!dir)
464 return -1;
465 add_entry_to_dir(dir, ref);
466 return 0;
467}
468
469/*
470 * Emit a warning and return true iff ref1 and ref2 have the same name
471 * and the same sha1. Die if they have the same name but different
472 * sha1s.
473 */
474static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
475{
476 if (strcmp(ref1->name, ref2->name))
477 return 0;
478
479 /* Duplicate name; make sure that they don't conflict: */
480
481 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
482 /* This is impossible by construction */
483 die("Reference directory conflict: %s", ref1->name);
484
485 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
486 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
487
488 warning("Duplicated ref: %s", ref1->name);
489 return 1;
490}
491
492/*
493 * Sort the entries in dir non-recursively (if they are not already
494 * sorted) and remove any duplicate entries.
495 */
496static void sort_ref_dir(struct ref_dir *dir)
497{
498 int i, j;
499 struct ref_entry *last = NULL;
500
501 /*
502 * This check also prevents passing a zero-length array to qsort(),
503 * which is a problem on some platforms.
504 */
505 if (dir->sorted == dir->nr)
506 return;
507
9ed0d8d6 508 QSORT(dir->entries, dir->nr, ref_entry_cmp);
7bd9bcf3
MH
509
510 /* Remove any duplicates: */
511 for (i = 0, j = 0; j < dir->nr; j++) {
512 struct ref_entry *entry = dir->entries[j];
513 if (last && is_dup_ref(last, entry))
514 free_ref_entry(entry);
515 else
516 last = dir->entries[i++] = entry;
517 }
518 dir->sorted = dir->nr = i;
519}
520
7bd9bcf3 521/*
a8739244
MH
522 * Return true if refname, which has the specified oid and flags, can
523 * be resolved to an object in the database. If the referred-to object
524 * does not exist, emit a warning and return false.
7bd9bcf3 525 */
a8739244
MH
526static int ref_resolves_to_object(const char *refname,
527 const struct object_id *oid,
528 unsigned int flags)
7bd9bcf3 529{
a8739244 530 if (flags & REF_ISBROKEN)
7bd9bcf3 531 return 0;
a8739244
MH
532 if (!has_sha1_file(oid->hash)) {
533 error("%s does not point to a valid object!", refname);
7bd9bcf3
MH
534 return 0;
535 }
536 return 1;
537}
538
539/*
a8739244
MH
540 * Return true if the reference described by entry can be resolved to
541 * an object in the database; otherwise, emit a warning and return
542 * false.
7bd9bcf3 543 */
a8739244 544static int entry_resolves_to_object(struct ref_entry *entry)
7bd9bcf3 545{
a8739244
MH
546 return ref_resolves_to_object(entry->name,
547 &entry->u.value.oid, entry->flag);
7bd9bcf3
MH
548}
549
7bd9bcf3
MH
550typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
551
7bd9bcf3
MH
552/*
553 * Call fn for each reference in dir that has index in the range
554 * offset <= index < dir->nr. Recurse into subdirectories that are in
555 * that index range, sorting them before iterating. This function
556 * does not sort dir itself; it should be sorted beforehand. fn is
557 * called for all references, including broken ones.
558 */
559static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
560 each_ref_entry_fn fn, void *cb_data)
561{
562 int i;
563 assert(dir->sorted == dir->nr);
564 for (i = offset; i < dir->nr; i++) {
565 struct ref_entry *entry = dir->entries[i];
566 int retval;
567 if (entry->flag & REF_DIR) {
568 struct ref_dir *subdir = get_ref_dir(entry);
569 sort_ref_dir(subdir);
570 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
571 } else {
572 retval = fn(entry, cb_data);
573 }
574 if (retval)
575 return retval;
576 }
577 return 0;
578}
579
7bd9bcf3
MH
580/*
581 * Load all of the refs from the dir into our in-memory cache. The hard work
582 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
583 * through all of the sub-directories. We do not even need to care about
584 * sorting, as traversal order does not matter to us.
585 */
586static void prime_ref_dir(struct ref_dir *dir)
587{
588 int i;
589 for (i = 0; i < dir->nr; i++) {
590 struct ref_entry *entry = dir->entries[i];
591 if (entry->flag & REF_DIR)
592 prime_ref_dir(get_ref_dir(entry));
593 }
594}
595
3bc581b9
MH
596/*
597 * A level in the reference hierarchy that is currently being iterated
598 * through.
599 */
600struct cache_ref_iterator_level {
601 /*
602 * The ref_dir being iterated over at this level. The ref_dir
603 * is sorted before being stored here.
604 */
605 struct ref_dir *dir;
606
607 /*
608 * The index of the current entry within dir (which might
609 * itself be a directory). If index == -1, then the iteration
610 * hasn't yet begun. If index == dir->nr, then the iteration
611 * through this level is over.
612 */
613 int index;
614};
615
616/*
617 * Represent an iteration through a ref_dir in the memory cache. The
618 * iteration recurses through subdirectories.
619 */
620struct cache_ref_iterator {
621 struct ref_iterator base;
622
623 /*
624 * The number of levels currently on the stack. This is always
625 * at least 1, because when it becomes zero the iteration is
626 * ended and this struct is freed.
627 */
628 size_t levels_nr;
629
630 /* The number of levels that have been allocated on the stack */
631 size_t levels_alloc;
632
633 /*
634 * A stack of levels. levels[0] is the uppermost level that is
635 * being iterated over in this iteration. (This is not
636 * necessary the top level in the references hierarchy. If we
637 * are iterating through a subtree, then levels[0] will hold
638 * the ref_dir for that subtree, and subsequent levels will go
639 * on from there.)
640 */
641 struct cache_ref_iterator_level *levels;
642};
643
644static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
645{
646 struct cache_ref_iterator *iter =
647 (struct cache_ref_iterator *)ref_iterator;
648
649 while (1) {
650 struct cache_ref_iterator_level *level =
651 &iter->levels[iter->levels_nr - 1];
652 struct ref_dir *dir = level->dir;
653 struct ref_entry *entry;
654
655 if (level->index == -1)
656 sort_ref_dir(dir);
657
658 if (++level->index == level->dir->nr) {
659 /* This level is exhausted; pop up a level */
660 if (--iter->levels_nr == 0)
661 return ref_iterator_abort(ref_iterator);
662
663 continue;
664 }
665
666 entry = dir->entries[level->index];
667
668 if (entry->flag & REF_DIR) {
669 /* push down a level */
670 ALLOC_GROW(iter->levels, iter->levels_nr + 1,
671 iter->levels_alloc);
672
673 level = &iter->levels[iter->levels_nr++];
674 level->dir = get_ref_dir(entry);
675 level->index = -1;
676 } else {
677 iter->base.refname = entry->name;
678 iter->base.oid = &entry->u.value.oid;
679 iter->base.flags = entry->flag;
680 return ITER_OK;
681 }
682 }
683}
684
685static enum peel_status peel_entry(struct ref_entry *entry, int repeel);
686
687static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
688 struct object_id *peeled)
689{
690 struct cache_ref_iterator *iter =
691 (struct cache_ref_iterator *)ref_iterator;
692 struct cache_ref_iterator_level *level;
693 struct ref_entry *entry;
694
695 level = &iter->levels[iter->levels_nr - 1];
696
697 if (level->index == -1)
698 die("BUG: peel called before advance for cache iterator");
699
700 entry = level->dir->entries[level->index];
701
702 if (peel_entry(entry, 0))
703 return -1;
8694769f 704 oidcpy(peeled, &entry->u.value.peeled);
3bc581b9
MH
705 return 0;
706}
707
708static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator)
709{
710 struct cache_ref_iterator *iter =
711 (struct cache_ref_iterator *)ref_iterator;
712
713 free(iter->levels);
714 base_ref_iterator_free(ref_iterator);
715 return ITER_DONE;
716}
717
718static struct ref_iterator_vtable cache_ref_iterator_vtable = {
719 cache_ref_iterator_advance,
720 cache_ref_iterator_peel,
721 cache_ref_iterator_abort
722};
723
724static struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir)
725{
726 struct cache_ref_iterator *iter;
727 struct ref_iterator *ref_iterator;
728 struct cache_ref_iterator_level *level;
729
730 iter = xcalloc(1, sizeof(*iter));
731 ref_iterator = &iter->base;
732 base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable);
733 ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
734
735 iter->levels_nr = 1;
736 level = &iter->levels[0];
737 level->index = -1;
738 level->dir = dir;
739
740 return ref_iterator;
741}
742
7bd9bcf3
MH
743struct nonmatching_ref_data {
744 const struct string_list *skip;
745 const char *conflicting_refname;
746};
747
748static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
749{
750 struct nonmatching_ref_data *data = vdata;
751
752 if (data->skip && string_list_has_string(data->skip, entry->name))
753 return 0;
754
755 data->conflicting_refname = entry->name;
756 return 1;
757}
758
759/*
760 * Return 0 if a reference named refname could be created without
761 * conflicting with the name of an existing reference in dir.
762 * See verify_refname_available for more information.
763 */
764static int verify_refname_available_dir(const char *refname,
765 const struct string_list *extras,
766 const struct string_list *skip,
767 struct ref_dir *dir,
768 struct strbuf *err)
769{
770 const char *slash;
0845122c 771 const char *extra_refname;
7bd9bcf3
MH
772 int pos;
773 struct strbuf dirname = STRBUF_INIT;
774 int ret = -1;
775
776 /*
777 * For the sake of comments in this function, suppose that
778 * refname is "refs/foo/bar".
779 */
780
781 assert(err);
782
783 strbuf_grow(&dirname, strlen(refname) + 1);
784 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
785 /* Expand dirname to the new prefix, not including the trailing slash: */
786 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
787
788 /*
789 * We are still at a leading dir of the refname (e.g.,
790 * "refs/foo"; if there is a reference with that name,
791 * it is a conflict, *unless* it is in skip.
792 */
793 if (dir) {
794 pos = search_ref_dir(dir, dirname.buf, dirname.len);
795 if (pos >= 0 &&
796 (!skip || !string_list_has_string(skip, dirname.buf))) {
797 /*
798 * We found a reference whose name is
799 * a proper prefix of refname; e.g.,
800 * "refs/foo", and is not in skip.
801 */
802 strbuf_addf(err, "'%s' exists; cannot create '%s'",
803 dirname.buf, refname);
804 goto cleanup;
805 }
806 }
807
808 if (extras && string_list_has_string(extras, dirname.buf) &&
809 (!skip || !string_list_has_string(skip, dirname.buf))) {
810 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
811 refname, dirname.buf);
812 goto cleanup;
813 }
814
815 /*
816 * Otherwise, we can try to continue our search with
817 * the next component. So try to look up the
818 * directory, e.g., "refs/foo/". If we come up empty,
819 * we know there is nothing under this whole prefix,
820 * but even in that case we still have to continue the
821 * search for conflicts with extras.
822 */
823 strbuf_addch(&dirname, '/');
824 if (dir) {
825 pos = search_ref_dir(dir, dirname.buf, dirname.len);
826 if (pos < 0) {
827 /*
828 * There was no directory "refs/foo/",
829 * so there is nothing under this
830 * whole prefix. So there is no need
831 * to continue looking for conflicting
832 * references. But we need to continue
833 * looking for conflicting extras.
834 */
835 dir = NULL;
836 } else {
837 dir = get_ref_dir(dir->entries[pos]);
838 }
839 }
840 }
841
842 /*
843 * We are at the leaf of our refname (e.g., "refs/foo/bar").
844 * There is no point in searching for a reference with that
845 * name, because a refname isn't considered to conflict with
846 * itself. But we still need to check for references whose
847 * names are in the "refs/foo/bar/" namespace, because they
848 * *do* conflict.
849 */
850 strbuf_addstr(&dirname, refname + dirname.len);
851 strbuf_addch(&dirname, '/');
852
853 if (dir) {
854 pos = search_ref_dir(dir, dirname.buf, dirname.len);
855
856 if (pos >= 0) {
857 /*
858 * We found a directory named "$refname/"
859 * (e.g., "refs/foo/bar/"). It is a problem
860 * iff it contains any ref that is not in
861 * "skip".
862 */
863 struct nonmatching_ref_data data;
864
865 data.skip = skip;
866 data.conflicting_refname = NULL;
867 dir = get_ref_dir(dir->entries[pos]);
868 sort_ref_dir(dir);
869 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
870 strbuf_addf(err, "'%s' exists; cannot create '%s'",
871 data.conflicting_refname, refname);
872 goto cleanup;
873 }
874 }
875 }
876
0845122c
DT
877 extra_refname = find_descendant_ref(dirname.buf, extras, skip);
878 if (extra_refname)
879 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
880 refname, extra_refname);
881 else
882 ret = 0;
7bd9bcf3
MH
883
884cleanup:
885 strbuf_release(&dirname);
886 return ret;
887}
888
889struct packed_ref_cache {
890 struct ref_entry *root;
891
892 /*
893 * Count of references to the data structure in this instance,
65a0a8e5
MH
894 * including the pointer from files_ref_store::packed if any.
895 * The data will not be freed as long as the reference count
896 * is nonzero.
7bd9bcf3
MH
897 */
898 unsigned int referrers;
899
900 /*
901 * Iff the packed-refs file associated with this instance is
902 * currently locked for writing, this points at the associated
903 * lock (which is owned by somebody else). The referrer count
904 * is also incremented when the file is locked and decremented
905 * when it is unlocked.
906 */
907 struct lock_file *lock;
908
909 /* The metadata from when this packed-refs cache was read */
910 struct stat_validity validity;
911};
912
913/*
914 * Future: need to be in "struct repository"
915 * when doing a full libification.
916 */
00eebe35
MH
917struct files_ref_store {
918 struct ref_store base;
9e7ec634 919 unsigned int store_flags;
32c597e7 920
f57f37e2
NTND
921 char *gitdir;
922 char *gitcommondir;
33dfb9f3
NTND
923 char *packed_refs_path;
924
7bd9bcf3
MH
925 struct ref_entry *loose;
926 struct packed_ref_cache *packed;
00eebe35 927};
7bd9bcf3
MH
928
929/* Lock used for the main packed-refs file: */
930static struct lock_file packlock;
931
932/*
933 * Increment the reference count of *packed_refs.
934 */
935static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
936{
937 packed_refs->referrers++;
938}
939
940/*
941 * Decrease the reference count of *packed_refs. If it goes to zero,
942 * free *packed_refs and return true; otherwise return false.
943 */
944static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
945{
946 if (!--packed_refs->referrers) {
947 free_ref_entry(packed_refs->root);
948 stat_validity_clear(&packed_refs->validity);
949 free(packed_refs);
950 return 1;
951 } else {
952 return 0;
953 }
954}
955
65a0a8e5 956static void clear_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
957{
958 if (refs->packed) {
959 struct packed_ref_cache *packed_refs = refs->packed;
960
961 if (packed_refs->lock)
962 die("internal error: packed-ref cache cleared while locked");
963 refs->packed = NULL;
964 release_packed_ref_cache(packed_refs);
965 }
966}
967
65a0a8e5 968static void clear_loose_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
969{
970 if (refs->loose) {
971 free_ref_entry(refs->loose);
972 refs->loose = NULL;
973 }
974}
975
a2d5156c
JK
976/*
977 * Create a new submodule ref cache and add it to the internal
978 * set of caches.
979 */
9e7ec634
NTND
980static struct ref_store *files_ref_store_create(const char *gitdir,
981 unsigned int flags)
7bd9bcf3 982{
00eebe35
MH
983 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
984 struct ref_store *ref_store = (struct ref_store *)refs;
f57f37e2 985 struct strbuf sb = STRBUF_INIT;
7bd9bcf3 986
fbfd0a29 987 base_ref_store_init(ref_store, &refs_be_files);
9e7ec634 988 refs->store_flags = flags;
7bd9bcf3 989
f57f37e2
NTND
990 refs->gitdir = xstrdup(gitdir);
991 get_common_dir_noenv(&sb, gitdir);
992 refs->gitcommondir = strbuf_detach(&sb, NULL);
993 strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
994 refs->packed_refs_path = strbuf_detach(&sb, NULL);
7bd9bcf3 995
00eebe35 996 return ref_store;
a2d5156c 997}
7bd9bcf3 998
32c597e7 999/*
9e7ec634
NTND
1000 * Die if refs is not the main ref store. caller is used in any
1001 * necessary error messages.
32c597e7
MH
1002 */
1003static void files_assert_main_repository(struct files_ref_store *refs,
1004 const char *caller)
1005{
9e7ec634
NTND
1006 if (refs->store_flags & REF_STORE_MAIN)
1007 return;
1008
1009 die("BUG: operation %s only allowed for main ref store", caller);
32c597e7
MH
1010}
1011
a2d5156c 1012/*
00eebe35 1013 * Downcast ref_store to files_ref_store. Die if ref_store is not a
9e7ec634
NTND
1014 * files_ref_store. required_flags is compared with ref_store's
1015 * store_flags to ensure the ref_store has all required capabilities.
1016 * "caller" is used in any necessary error messages.
a2d5156c 1017 */
9e7ec634
NTND
1018static struct files_ref_store *files_downcast(struct ref_store *ref_store,
1019 unsigned int required_flags,
1020 const char *caller)
a2d5156c 1021{
32c597e7
MH
1022 struct files_ref_store *refs;
1023
00eebe35
MH
1024 if (ref_store->be != &refs_be_files)
1025 die("BUG: ref_store is type \"%s\" not \"files\" in %s",
1026 ref_store->be->name, caller);
2eed2780 1027
32c597e7
MH
1028 refs = (struct files_ref_store *)ref_store;
1029
9e7ec634
NTND
1030 if ((refs->store_flags & required_flags) != required_flags)
1031 die("BUG: operation %s requires abilities 0x%x, but only have 0x%x",
1032 caller, required_flags, refs->store_flags);
2eed2780 1033
32c597e7 1034 return refs;
7bd9bcf3
MH
1035}
1036
1037/* The length of a peeled reference line in packed-refs, including EOL: */
1038#define PEELED_LINE_LENGTH 42
1039
1040/*
1041 * The packed-refs header line that we write out. Perhaps other
1042 * traits will be added later. The trailing space is required.
1043 */
1044static const char PACKED_REFS_HEADER[] =
1045 "# pack-refs with: peeled fully-peeled \n";
1046
1047/*
1048 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1049 * Return a pointer to the refname within the line (null-terminated),
1050 * or NULL if there was a problem.
1051 */
1052static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1053{
1054 const char *ref;
1055
1056 /*
1057 * 42: the answer to everything.
1058 *
1059 * In this case, it happens to be the answer to
1060 * 40 (length of sha1 hex representation)
1061 * +1 (space in between hex and name)
1062 * +1 (newline at the end of the line)
1063 */
1064 if (line->len <= 42)
1065 return NULL;
1066
1067 if (get_sha1_hex(line->buf, sha1) < 0)
1068 return NULL;
1069 if (!isspace(line->buf[40]))
1070 return NULL;
1071
1072 ref = line->buf + 41;
1073 if (isspace(*ref))
1074 return NULL;
1075
1076 if (line->buf[line->len - 1] != '\n')
1077 return NULL;
1078 line->buf[--line->len] = 0;
1079
1080 return ref;
1081}
1082
1083/*
1084 * Read f, which is a packed-refs file, into dir.
1085 *
1086 * A comment line of the form "# pack-refs with: " may contain zero or
1087 * more traits. We interpret the traits as follows:
1088 *
1089 * No traits:
1090 *
1091 * Probably no references are peeled. But if the file contains a
1092 * peeled value for a reference, we will use it.
1093 *
1094 * peeled:
1095 *
1096 * References under "refs/tags/", if they *can* be peeled, *are*
1097 * peeled in this file. References outside of "refs/tags/" are
1098 * probably not peeled even if they could have been, but if we find
1099 * a peeled value for such a reference we will use it.
1100 *
1101 * fully-peeled:
1102 *
1103 * All references in the file that can be peeled are peeled.
1104 * Inversely (and this is more important), any references in the
1105 * file for which no peeled value is recorded is not peelable. This
1106 * trait should typically be written alongside "peeled" for
1107 * compatibility with older clients, but we do not require it
1108 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1109 */
1110static void read_packed_refs(FILE *f, struct ref_dir *dir)
1111{
1112 struct ref_entry *last = NULL;
1113 struct strbuf line = STRBUF_INIT;
1114 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1115
1116 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1117 unsigned char sha1[20];
1118 const char *refname;
1119 const char *traits;
1120
1121 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1122 if (strstr(traits, " fully-peeled "))
1123 peeled = PEELED_FULLY;
1124 else if (strstr(traits, " peeled "))
1125 peeled = PEELED_TAGS;
1126 /* perhaps other traits later as well */
1127 continue;
1128 }
1129
1130 refname = parse_ref_line(&line, sha1);
1131 if (refname) {
1132 int flag = REF_ISPACKED;
1133
1134 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1135 if (!refname_is_safe(refname))
1136 die("packed refname is dangerous: %s", refname);
1137 hashclr(sha1);
1138 flag |= REF_BAD_NAME | REF_ISBROKEN;
1139 }
1140 last = create_ref_entry(refname, sha1, flag, 0);
1141 if (peeled == PEELED_FULLY ||
1142 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1143 last->flag |= REF_KNOWS_PEELED;
1144 add_ref(dir, last);
1145 continue;
1146 }
1147 if (last &&
1148 line.buf[0] == '^' &&
1149 line.len == PEELED_LINE_LENGTH &&
1150 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1151 !get_sha1_hex(line.buf + 1, sha1)) {
1152 hashcpy(last->u.value.peeled.hash, sha1);
1153 /*
1154 * Regardless of what the file header said,
1155 * we definitely know the value of *this*
1156 * reference:
1157 */
1158 last->flag |= REF_KNOWS_PEELED;
1159 }
1160 }
1161
1162 strbuf_release(&line);
1163}
1164
33dfb9f3
NTND
1165static const char *files_packed_refs_path(struct files_ref_store *refs)
1166{
1167 return refs->packed_refs_path;
1168}
1169
802de3da
NTND
1170static void files_reflog_path(struct files_ref_store *refs,
1171 struct strbuf *sb,
1172 const char *refname)
1173{
1174 if (!refname) {
f57f37e2
NTND
1175 /*
1176 * FIXME: of course this is wrong in multi worktree
1177 * setting. To be fixed real soon.
1178 */
1179 strbuf_addf(sb, "%s/logs", refs->gitcommondir);
802de3da
NTND
1180 return;
1181 }
1182
f57f37e2
NTND
1183 switch (ref_type(refname)) {
1184 case REF_TYPE_PER_WORKTREE:
1185 case REF_TYPE_PSEUDOREF:
1186 strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
1187 break;
1188 case REF_TYPE_NORMAL:
1189 strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
1190 break;
1191 default:
1192 die("BUG: unknown ref type %d of ref %s",
1193 ref_type(refname), refname);
1194 }
802de3da
NTND
1195}
1196
19e02f4f
NTND
1197static void files_ref_path(struct files_ref_store *refs,
1198 struct strbuf *sb,
1199 const char *refname)
1200{
f57f37e2
NTND
1201 switch (ref_type(refname)) {
1202 case REF_TYPE_PER_WORKTREE:
1203 case REF_TYPE_PSEUDOREF:
1204 strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
1205 break;
1206 case REF_TYPE_NORMAL:
1207 strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
1208 break;
1209 default:
1210 die("BUG: unknown ref type %d of ref %s",
1211 ref_type(refname), refname);
1212 }
19e02f4f
NTND
1213}
1214
7bd9bcf3 1215/*
65a0a8e5
MH
1216 * Get the packed_ref_cache for the specified files_ref_store,
1217 * creating it if necessary.
7bd9bcf3 1218 */
65a0a8e5 1219static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3 1220{
33dfb9f3 1221 const char *packed_refs_file = files_packed_refs_path(refs);
7bd9bcf3
MH
1222
1223 if (refs->packed &&
1224 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1225 clear_packed_ref_cache(refs);
1226
1227 if (!refs->packed) {
1228 FILE *f;
1229
1230 refs->packed = xcalloc(1, sizeof(*refs->packed));
1231 acquire_packed_ref_cache(refs->packed);
1232 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1233 f = fopen(packed_refs_file, "r");
1234 if (f) {
1235 stat_validity_update(&refs->packed->validity, fileno(f));
1236 read_packed_refs(f, get_ref_dir(refs->packed->root));
1237 fclose(f);
1238 }
1239 }
7bd9bcf3
MH
1240 return refs->packed;
1241}
1242
1243static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1244{
1245 return get_ref_dir(packed_ref_cache->root);
1246}
1247
65a0a8e5 1248static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1249{
1250 return get_packed_ref_dir(get_packed_ref_cache(refs));
1251}
1252
1253/*
1254 * Add a reference to the in-memory packed reference cache. This may
1255 * only be called while the packed-refs file is locked (see
1256 * lock_packed_refs()). To actually write the packed-refs file, call
1257 * commit_packed_refs().
1258 */
d99825ab
MH
1259static void add_packed_ref(struct files_ref_store *refs,
1260 const char *refname, const unsigned char *sha1)
7bd9bcf3 1261{
00eebe35 1262 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
1263
1264 if (!packed_ref_cache->lock)
1265 die("internal error: packed refs not locked");
1266 add_ref(get_packed_ref_dir(packed_ref_cache),
1267 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1268}
1269
1270/*
1271 * Read the loose references from the namespace dirname into dir
1272 * (without recursing). dirname must end with '/'. dir must be the
1273 * directory entry corresponding to dirname.
1274 */
1275static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1276{
65a0a8e5 1277 struct files_ref_store *refs = dir->ref_store;
7bd9bcf3
MH
1278 DIR *d;
1279 struct dirent *de;
1280 int dirnamelen = strlen(dirname);
1281 struct strbuf refname;
1282 struct strbuf path = STRBUF_INIT;
1283 size_t path_baselen;
1284
19e02f4f 1285 files_ref_path(refs, &path, dirname);
7bd9bcf3
MH
1286 path_baselen = path.len;
1287
1288 d = opendir(path.buf);
1289 if (!d) {
1290 strbuf_release(&path);
1291 return;
1292 }
1293
1294 strbuf_init(&refname, dirnamelen + 257);
1295 strbuf_add(&refname, dirname, dirnamelen);
1296
1297 while ((de = readdir(d)) != NULL) {
1298 unsigned char sha1[20];
1299 struct stat st;
1300 int flag;
1301
1302 if (de->d_name[0] == '.')
1303 continue;
1304 if (ends_with(de->d_name, ".lock"))
1305 continue;
1306 strbuf_addstr(&refname, de->d_name);
1307 strbuf_addstr(&path, de->d_name);
1308 if (stat(path.buf, &st) < 0) {
1309 ; /* silently ignore */
1310 } else if (S_ISDIR(st.st_mode)) {
1311 strbuf_addch(&refname, '/');
1312 add_entry_to_dir(dir,
1313 create_dir_entry(refs, refname.buf,
1314 refname.len, 1));
1315 } else {
3c0cb0cb
MH
1316 if (!resolve_ref_recursively(&refs->base,
1317 refname.buf,
1318 RESOLVE_REF_READING,
1319 sha1, &flag)) {
7bd9bcf3
MH
1320 hashclr(sha1);
1321 flag |= REF_ISBROKEN;
1322 } else if (is_null_sha1(sha1)) {
1323 /*
1324 * It is so astronomically unlikely
1325 * that NULL_SHA1 is the SHA-1 of an
1326 * actual object that we consider its
1327 * appearance in a loose reference
1328 * file to be repo corruption
1329 * (probably due to a software bug).
1330 */
1331 flag |= REF_ISBROKEN;
1332 }
1333
1334 if (check_refname_format(refname.buf,
1335 REFNAME_ALLOW_ONELEVEL)) {
1336 if (!refname_is_safe(refname.buf))
1337 die("loose refname is dangerous: %s", refname.buf);
1338 hashclr(sha1);
1339 flag |= REF_BAD_NAME | REF_ISBROKEN;
1340 }
1341 add_entry_to_dir(dir,
1342 create_ref_entry(refname.buf, sha1, flag, 0));
1343 }
1344 strbuf_setlen(&refname, dirnamelen);
1345 strbuf_setlen(&path, path_baselen);
1346 }
1347 strbuf_release(&refname);
1348 strbuf_release(&path);
1349 closedir(d);
1350}
1351
65a0a8e5 1352static struct ref_dir *get_loose_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1353{
1354 if (!refs->loose) {
1355 /*
1356 * Mark the top-level directory complete because we
1357 * are about to read the only subdirectory that can
1358 * hold references:
1359 */
1360 refs->loose = create_dir_entry(refs, "", 0, 0);
1361 /*
1362 * Create an incomplete entry for "refs/":
1363 */
1364 add_entry_to_dir(get_ref_dir(refs->loose),
1365 create_dir_entry(refs, "refs/", 5, 1));
1366 }
1367 return get_ref_dir(refs->loose);
1368}
1369
7bd9bcf3
MH
1370/*
1371 * Return the ref_entry for the given refname from the packed
1372 * references. If it does not exist, return NULL.
1373 */
f0d21efc
MH
1374static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
1375 const char *refname)
7bd9bcf3 1376{
00eebe35 1377 return find_ref(get_packed_refs(refs), refname);
7bd9bcf3
MH
1378}
1379
1380/*
419c6f4c 1381 * A loose ref file doesn't exist; check for a packed ref.
7bd9bcf3 1382 */
611118d0
MH
1383static int resolve_packed_ref(struct files_ref_store *refs,
1384 const char *refname,
1385 unsigned char *sha1, unsigned int *flags)
7bd9bcf3
MH
1386{
1387 struct ref_entry *entry;
1388
1389 /*
1390 * The loose reference file does not exist; check for a packed
1391 * reference.
1392 */
f0d21efc 1393 entry = get_packed_ref(refs, refname);
7bd9bcf3
MH
1394 if (entry) {
1395 hashcpy(sha1, entry->u.value.oid.hash);
a70a93b7 1396 *flags |= REF_ISPACKED;
7bd9bcf3
MH
1397 return 0;
1398 }
419c6f4c
MH
1399 /* refname is not a packed reference. */
1400 return -1;
7bd9bcf3
MH
1401}
1402
e1e33b72
MH
1403static int files_read_raw_ref(struct ref_store *ref_store,
1404 const char *refname, unsigned char *sha1,
1405 struct strbuf *referent, unsigned int *type)
7bd9bcf3 1406{
4308651c 1407 struct files_ref_store *refs =
9e7ec634 1408 files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
42a38cf7
MH
1409 struct strbuf sb_contents = STRBUF_INIT;
1410 struct strbuf sb_path = STRBUF_INIT;
7048653a
DT
1411 const char *path;
1412 const char *buf;
1413 struct stat st;
1414 int fd;
42a38cf7
MH
1415 int ret = -1;
1416 int save_errno;
e8c42cb9 1417 int remaining_retries = 3;
7bd9bcf3 1418
fa96ea1b 1419 *type = 0;
42a38cf7 1420 strbuf_reset(&sb_path);
34c7ad8f 1421
19e02f4f 1422 files_ref_path(refs, &sb_path, refname);
34c7ad8f 1423
42a38cf7 1424 path = sb_path.buf;
7bd9bcf3 1425
7048653a
DT
1426stat_ref:
1427 /*
1428 * We might have to loop back here to avoid a race
1429 * condition: first we lstat() the file, then we try
1430 * to read it as a link or as a file. But if somebody
1431 * changes the type of the file (file <-> directory
1432 * <-> symlink) between the lstat() and reading, then
1433 * we don't want to report that as an error but rather
1434 * try again starting with the lstat().
e8c42cb9
JK
1435 *
1436 * We'll keep a count of the retries, though, just to avoid
1437 * any confusing situation sending us into an infinite loop.
7048653a 1438 */
7bd9bcf3 1439
e8c42cb9
JK
1440 if (remaining_retries-- <= 0)
1441 goto out;
1442
7048653a
DT
1443 if (lstat(path, &st) < 0) {
1444 if (errno != ENOENT)
42a38cf7 1445 goto out;
611118d0 1446 if (resolve_packed_ref(refs, refname, sha1, type)) {
7048653a 1447 errno = ENOENT;
42a38cf7 1448 goto out;
7bd9bcf3 1449 }
42a38cf7
MH
1450 ret = 0;
1451 goto out;
7bd9bcf3 1452 }
7bd9bcf3 1453
7048653a
DT
1454 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1455 if (S_ISLNK(st.st_mode)) {
42a38cf7
MH
1456 strbuf_reset(&sb_contents);
1457 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
7048653a 1458 if (errno == ENOENT || errno == EINVAL)
7bd9bcf3
MH
1459 /* inconsistent with lstat; retry */
1460 goto stat_ref;
1461 else
42a38cf7 1462 goto out;
7bd9bcf3 1463 }
42a38cf7
MH
1464 if (starts_with(sb_contents.buf, "refs/") &&
1465 !check_refname_format(sb_contents.buf, 0)) {
92b38093 1466 strbuf_swap(&sb_contents, referent);
3a0b6b9a 1467 *type |= REF_ISSYMREF;
42a38cf7
MH
1468 ret = 0;
1469 goto out;
7bd9bcf3 1470 }
3f7bd767
JK
1471 /*
1472 * It doesn't look like a refname; fall through to just
1473 * treating it like a non-symlink, and reading whatever it
1474 * points to.
1475 */
7048653a 1476 }
7bd9bcf3 1477
7048653a
DT
1478 /* Is it a directory? */
1479 if (S_ISDIR(st.st_mode)) {
e167a567
MH
1480 /*
1481 * Even though there is a directory where the loose
1482 * ref is supposed to be, there could still be a
1483 * packed ref:
1484 */
611118d0 1485 if (resolve_packed_ref(refs, refname, sha1, type)) {
e167a567
MH
1486 errno = EISDIR;
1487 goto out;
1488 }
1489 ret = 0;
42a38cf7 1490 goto out;
7048653a
DT
1491 }
1492
1493 /*
1494 * Anything else, just open it and try to use it as
1495 * a ref
1496 */
1497 fd = open(path, O_RDONLY);
1498 if (fd < 0) {
3f7bd767 1499 if (errno == ENOENT && !S_ISLNK(st.st_mode))
7048653a
DT
1500 /* inconsistent with lstat; retry */
1501 goto stat_ref;
1502 else
42a38cf7 1503 goto out;
7048653a 1504 }
42a38cf7
MH
1505 strbuf_reset(&sb_contents);
1506 if (strbuf_read(&sb_contents, fd, 256) < 0) {
7048653a
DT
1507 int save_errno = errno;
1508 close(fd);
1509 errno = save_errno;
42a38cf7 1510 goto out;
7048653a
DT
1511 }
1512 close(fd);
42a38cf7
MH
1513 strbuf_rtrim(&sb_contents);
1514 buf = sb_contents.buf;
7048653a
DT
1515 if (starts_with(buf, "ref:")) {
1516 buf += 4;
7bd9bcf3
MH
1517 while (isspace(*buf))
1518 buf++;
7048653a 1519
92b38093
MH
1520 strbuf_reset(referent);
1521 strbuf_addstr(referent, buf);
3a0b6b9a 1522 *type |= REF_ISSYMREF;
42a38cf7
MH
1523 ret = 0;
1524 goto out;
7bd9bcf3 1525 }
7bd9bcf3 1526
7048653a
DT
1527 /*
1528 * Please note that FETCH_HEAD has additional
1529 * data after the sha.
1530 */
1531 if (get_sha1_hex(buf, sha1) ||
1532 (buf[40] != '\0' && !isspace(buf[40]))) {
3a0b6b9a 1533 *type |= REF_ISBROKEN;
7048653a 1534 errno = EINVAL;
42a38cf7 1535 goto out;
7048653a
DT
1536 }
1537
42a38cf7 1538 ret = 0;
7bd9bcf3 1539
42a38cf7
MH
1540out:
1541 save_errno = errno;
7bd9bcf3
MH
1542 strbuf_release(&sb_path);
1543 strbuf_release(&sb_contents);
42a38cf7 1544 errno = save_errno;
7bd9bcf3
MH
1545 return ret;
1546}
1547
8415d247
MH
1548static void unlock_ref(struct ref_lock *lock)
1549{
1550 /* Do not free lock->lk -- atexit() still looks at them */
1551 if (lock->lk)
1552 rollback_lock_file(lock->lk);
1553 free(lock->ref_name);
8415d247
MH
1554 free(lock);
1555}
1556
92b1551b
MH
1557/*
1558 * Lock refname, without following symrefs, and set *lock_p to point
1559 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
1560 * and type similarly to read_raw_ref().
1561 *
1562 * The caller must verify that refname is a "safe" reference name (in
1563 * the sense of refname_is_safe()) before calling this function.
1564 *
1565 * If the reference doesn't already exist, verify that refname doesn't
1566 * have a D/F conflict with any existing references. extras and skip
1567 * are passed to verify_refname_available_dir() for this check.
1568 *
1569 * If mustexist is not set and the reference is not found or is
1570 * broken, lock the reference anyway but clear sha1.
1571 *
1572 * Return 0 on success. On failure, write an error message to err and
1573 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
1574 *
1575 * Implementation note: This function is basically
1576 *
1577 * lock reference
1578 * read_raw_ref()
1579 *
1580 * but it includes a lot more code to
1581 * - Deal with possible races with other processes
1582 * - Avoid calling verify_refname_available_dir() when it can be
1583 * avoided, namely if we were successfully able to read the ref
1584 * - Generate informative error messages in the case of failure
1585 */
f7b0a987
MH
1586static int lock_raw_ref(struct files_ref_store *refs,
1587 const char *refname, int mustexist,
92b1551b
MH
1588 const struct string_list *extras,
1589 const struct string_list *skip,
1590 struct ref_lock **lock_p,
1591 struct strbuf *referent,
1592 unsigned int *type,
1593 struct strbuf *err)
1594{
1595 struct ref_lock *lock;
1596 struct strbuf ref_file = STRBUF_INIT;
1597 int attempts_remaining = 3;
1598 int ret = TRANSACTION_GENERIC_ERROR;
1599
1600 assert(err);
32c597e7 1601 files_assert_main_repository(refs, "lock_raw_ref");
f7b0a987 1602
92b1551b
MH
1603 *type = 0;
1604
1605 /* First lock the file so it can't change out from under us. */
1606
1607 *lock_p = lock = xcalloc(1, sizeof(*lock));
1608
1609 lock->ref_name = xstrdup(refname);
19e02f4f 1610 files_ref_path(refs, &ref_file, refname);
92b1551b
MH
1611
1612retry:
1613 switch (safe_create_leading_directories(ref_file.buf)) {
1614 case SCLD_OK:
1615 break; /* success */
1616 case SCLD_EXISTS:
1617 /*
1618 * Suppose refname is "refs/foo/bar". We just failed
1619 * to create the containing directory, "refs/foo",
1620 * because there was a non-directory in the way. This
1621 * indicates a D/F conflict, probably because of
1622 * another reference such as "refs/foo". There is no
1623 * reason to expect this error to be transitory.
1624 */
1625 if (verify_refname_available(refname, extras, skip, err)) {
1626 if (mustexist) {
1627 /*
1628 * To the user the relevant error is
1629 * that the "mustexist" reference is
1630 * missing:
1631 */
1632 strbuf_reset(err);
1633 strbuf_addf(err, "unable to resolve reference '%s'",
1634 refname);
1635 } else {
1636 /*
1637 * The error message set by
1638 * verify_refname_available_dir() is OK.
1639 */
1640 ret = TRANSACTION_NAME_CONFLICT;
1641 }
1642 } else {
1643 /*
1644 * The file that is in the way isn't a loose
1645 * reference. Report it as a low-level
1646 * failure.
1647 */
1648 strbuf_addf(err, "unable to create lock file %s.lock; "
1649 "non-directory in the way",
1650 ref_file.buf);
1651 }
1652 goto error_return;
1653 case SCLD_VANISHED:
1654 /* Maybe another process was tidying up. Try again. */
1655 if (--attempts_remaining > 0)
1656 goto retry;
1657 /* fall through */
1658 default:
1659 strbuf_addf(err, "unable to create directory for %s",
1660 ref_file.buf);
1661 goto error_return;
1662 }
1663
1664 if (!lock->lk)
1665 lock->lk = xcalloc(1, sizeof(struct lock_file));
1666
1667 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
1668 if (errno == ENOENT && --attempts_remaining > 0) {
1669 /*
1670 * Maybe somebody just deleted one of the
1671 * directories leading to ref_file. Try
1672 * again:
1673 */
1674 goto retry;
1675 } else {
1676 unable_to_lock_message(ref_file.buf, errno, err);
1677 goto error_return;
1678 }
1679 }
1680
1681 /*
1682 * Now we hold the lock and can read the reference without
1683 * fear that its value will change.
1684 */
1685
f7b0a987 1686 if (files_read_raw_ref(&refs->base, refname,
e1e33b72 1687 lock->old_oid.hash, referent, type)) {
92b1551b
MH
1688 if (errno == ENOENT) {
1689 if (mustexist) {
1690 /* Garden variety missing reference. */
1691 strbuf_addf(err, "unable to resolve reference '%s'",
1692 refname);
1693 goto error_return;
1694 } else {
1695 /*
1696 * Reference is missing, but that's OK. We
1697 * know that there is not a conflict with
1698 * another loose reference because
1699 * (supposing that we are trying to lock
1700 * reference "refs/foo/bar"):
1701 *
1702 * - We were successfully able to create
1703 * the lockfile refs/foo/bar.lock, so we
1704 * know there cannot be a loose reference
1705 * named "refs/foo".
1706 *
1707 * - We got ENOENT and not EISDIR, so we
1708 * know that there cannot be a loose
1709 * reference named "refs/foo/bar/baz".
1710 */
1711 }
1712 } else if (errno == EISDIR) {
1713 /*
1714 * There is a directory in the way. It might have
1715 * contained references that have been deleted. If
1716 * we don't require that the reference already
1717 * exists, try to remove the directory so that it
1718 * doesn't cause trouble when we want to rename the
1719 * lockfile into place later.
1720 */
1721 if (mustexist) {
1722 /* Garden variety missing reference. */
1723 strbuf_addf(err, "unable to resolve reference '%s'",
1724 refname);
1725 goto error_return;
1726 } else if (remove_dir_recursively(&ref_file,
1727 REMOVE_DIR_EMPTY_ONLY)) {
1728 if (verify_refname_available_dir(
1729 refname, extras, skip,
00eebe35 1730 get_loose_refs(refs),
92b1551b
MH
1731 err)) {
1732 /*
1733 * The error message set by
1734 * verify_refname_available() is OK.
1735 */
1736 ret = TRANSACTION_NAME_CONFLICT;
1737 goto error_return;
1738 } else {
1739 /*
1740 * We can't delete the directory,
1741 * but we also don't know of any
1742 * references that it should
1743 * contain.
1744 */
1745 strbuf_addf(err, "there is a non-empty directory '%s' "
1746 "blocking reference '%s'",
1747 ref_file.buf, refname);
1748 goto error_return;
1749 }
1750 }
1751 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
1752 strbuf_addf(err, "unable to resolve reference '%s': "
1753 "reference broken", refname);
1754 goto error_return;
1755 } else {
1756 strbuf_addf(err, "unable to resolve reference '%s': %s",
1757 refname, strerror(errno));
1758 goto error_return;
1759 }
1760
1761 /*
1762 * If the ref did not exist and we are creating it,
1763 * make sure there is no existing packed ref whose
1764 * name begins with our refname, nor a packed ref
1765 * whose name is a proper prefix of our refname.
1766 */
1767 if (verify_refname_available_dir(
1768 refname, extras, skip,
00eebe35 1769 get_packed_refs(refs),
92b1551b
MH
1770 err)) {
1771 goto error_return;
1772 }
1773 }
1774
1775 ret = 0;
1776 goto out;
1777
1778error_return:
1779 unlock_ref(lock);
1780 *lock_p = NULL;
1781
1782out:
1783 strbuf_release(&ref_file);
1784 return ret;
1785}
1786
7bd9bcf3
MH
1787/*
1788 * Peel the entry (if possible) and return its new peel_status. If
1789 * repeel is true, re-peel the entry even if there is an old peeled
1790 * value that is already stored in it.
1791 *
1792 * It is OK to call this function with a packed reference entry that
1793 * might be stale and might even refer to an object that has since
1794 * been garbage-collected. In such a case, if the entry has
1795 * REF_KNOWS_PEELED then leave the status unchanged and return
1796 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1797 */
1798static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1799{
1800 enum peel_status status;
1801
1802 if (entry->flag & REF_KNOWS_PEELED) {
1803 if (repeel) {
1804 entry->flag &= ~REF_KNOWS_PEELED;
1805 oidclr(&entry->u.value.peeled);
1806 } else {
1807 return is_null_oid(&entry->u.value.peeled) ?
1808 PEEL_NON_TAG : PEEL_PEELED;
1809 }
1810 }
1811 if (entry->flag & REF_ISBROKEN)
1812 return PEEL_BROKEN;
1813 if (entry->flag & REF_ISSYMREF)
1814 return PEEL_IS_SYMREF;
1815
1816 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1817 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1818 entry->flag |= REF_KNOWS_PEELED;
1819 return status;
1820}
1821
bd427cf2
MH
1822static int files_peel_ref(struct ref_store *ref_store,
1823 const char *refname, unsigned char *sha1)
7bd9bcf3 1824{
9e7ec634
NTND
1825 struct files_ref_store *refs =
1826 files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
1827 "peel_ref");
7bd9bcf3
MH
1828 int flag;
1829 unsigned char base[20];
1830
9e7ec634
NTND
1831 files_assert_main_repository(refs, "peel_ref");
1832
4c4de895
MH
1833 if (current_ref_iter && current_ref_iter->refname == refname) {
1834 struct object_id peeled;
1835
1836 if (ref_iterator_peel(current_ref_iter, &peeled))
7bd9bcf3 1837 return -1;
4c4de895 1838 hashcpy(sha1, peeled.hash);
7bd9bcf3
MH
1839 return 0;
1840 }
1841
1842 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1843 return -1;
1844
1845 /*
1846 * If the reference is packed, read its ref_entry from the
1847 * cache in the hope that we already know its peeled value.
1848 * We only try this optimization on packed references because
1849 * (a) forcing the filling of the loose reference cache could
1850 * be expensive and (b) loose references anyway usually do not
1851 * have REF_KNOWS_PEELED.
1852 */
1853 if (flag & REF_ISPACKED) {
f0d21efc 1854 struct ref_entry *r = get_packed_ref(refs, refname);
7bd9bcf3
MH
1855 if (r) {
1856 if (peel_entry(r, 0))
1857 return -1;
1858 hashcpy(sha1, r->u.value.peeled.hash);
1859 return 0;
1860 }
1861 }
1862
1863 return peel_object(base, sha1);
1864}
1865
3bc581b9
MH
1866struct files_ref_iterator {
1867 struct ref_iterator base;
1868
7bd9bcf3 1869 struct packed_ref_cache *packed_ref_cache;
3bc581b9
MH
1870 struct ref_iterator *iter0;
1871 unsigned int flags;
1872};
7bd9bcf3 1873
3bc581b9
MH
1874static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
1875{
1876 struct files_ref_iterator *iter =
1877 (struct files_ref_iterator *)ref_iterator;
1878 int ok;
7bd9bcf3 1879
3bc581b9 1880 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
0c09ec07
DT
1881 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
1882 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
1883 continue;
1884
3bc581b9
MH
1885 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
1886 !ref_resolves_to_object(iter->iter0->refname,
1887 iter->iter0->oid,
1888 iter->iter0->flags))
1889 continue;
1890
1891 iter->base.refname = iter->iter0->refname;
1892 iter->base.oid = iter->iter0->oid;
1893 iter->base.flags = iter->iter0->flags;
1894 return ITER_OK;
7bd9bcf3
MH
1895 }
1896
3bc581b9
MH
1897 iter->iter0 = NULL;
1898 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
1899 ok = ITER_ERROR;
1900
1901 return ok;
7bd9bcf3
MH
1902}
1903
3bc581b9
MH
1904static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
1905 struct object_id *peeled)
7bd9bcf3 1906{
3bc581b9
MH
1907 struct files_ref_iterator *iter =
1908 (struct files_ref_iterator *)ref_iterator;
93770590 1909
3bc581b9
MH
1910 return ref_iterator_peel(iter->iter0, peeled);
1911}
1912
1913static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
1914{
1915 struct files_ref_iterator *iter =
1916 (struct files_ref_iterator *)ref_iterator;
1917 int ok = ITER_DONE;
1918
1919 if (iter->iter0)
1920 ok = ref_iterator_abort(iter->iter0);
1921
1922 release_packed_ref_cache(iter->packed_ref_cache);
1923 base_ref_iterator_free(ref_iterator);
1924 return ok;
1925}
1926
1927static struct ref_iterator_vtable files_ref_iterator_vtable = {
1928 files_ref_iterator_advance,
1929 files_ref_iterator_peel,
1930 files_ref_iterator_abort
1931};
1932
1a769003 1933static struct ref_iterator *files_ref_iterator_begin(
37b6f6d5 1934 struct ref_store *ref_store,
3bc581b9
MH
1935 const char *prefix, unsigned int flags)
1936{
9e7ec634 1937 struct files_ref_store *refs;
3bc581b9
MH
1938 struct ref_dir *loose_dir, *packed_dir;
1939 struct ref_iterator *loose_iter, *packed_iter;
1940 struct files_ref_iterator *iter;
1941 struct ref_iterator *ref_iterator;
1942
7bd9bcf3
MH
1943 if (ref_paranoia < 0)
1944 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1945 if (ref_paranoia)
3bc581b9
MH
1946 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1947
9e7ec634
NTND
1948 refs = files_downcast(ref_store,
1949 REF_STORE_READ | (ref_paranoia ? 0 : REF_STORE_ODB),
1950 "ref_iterator_begin");
1951
3bc581b9
MH
1952 iter = xcalloc(1, sizeof(*iter));
1953 ref_iterator = &iter->base;
1954 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
1955
1956 /*
1957 * We must make sure that all loose refs are read before
1958 * accessing the packed-refs file; this avoids a race
1959 * condition if loose refs are migrated to the packed-refs
1960 * file by a simultaneous process, but our in-memory view is
1961 * from before the migration. We ensure this as follows:
1962 * First, we call prime_ref_dir(), which pre-reads the loose
1963 * references for the subtree into the cache. (If they've
1964 * already been read, that's OK; we only need to guarantee
1965 * that they're read before the packed refs, not *how much*
1966 * before.) After that, we call get_packed_ref_cache(), which
1967 * internally checks whether the packed-ref cache is up to
1968 * date with what is on disk, and re-reads it if not.
1969 */
1970
1971 loose_dir = get_loose_refs(refs);
1972
1973 if (prefix && *prefix)
1974 loose_dir = find_containing_dir(loose_dir, prefix, 0);
7bd9bcf3 1975
3bc581b9
MH
1976 if (loose_dir) {
1977 prime_ref_dir(loose_dir);
1978 loose_iter = cache_ref_iterator_begin(loose_dir);
1979 } else {
1980 /* There's nothing to iterate over. */
1981 loose_iter = empty_ref_iterator_begin();
1982 }
1983
1984 iter->packed_ref_cache = get_packed_ref_cache(refs);
1985 acquire_packed_ref_cache(iter->packed_ref_cache);
1986 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);
1987
1988 if (prefix && *prefix)
1989 packed_dir = find_containing_dir(packed_dir, prefix, 0);
1990
1991 if (packed_dir) {
1992 packed_iter = cache_ref_iterator_begin(packed_dir);
1993 } else {
1994 /* There's nothing to iterate over. */
1995 packed_iter = empty_ref_iterator_begin();
1996 }
1997
1998 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
1999 iter->flags = flags;
2000
2001 return ref_iterator;
7bd9bcf3
MH
2002}
2003
7bd9bcf3
MH
2004/*
2005 * Verify that the reference locked by lock has the value old_sha1.
2006 * Fail if the reference doesn't exist and mustexist is set. Return 0
2007 * on success. On error, write an error message to err, set errno, and
2008 * return a negative value.
2009 */
2010static int verify_lock(struct ref_lock *lock,
2011 const unsigned char *old_sha1, int mustexist,
2012 struct strbuf *err)
2013{
2014 assert(err);
2015
2016 if (read_ref_full(lock->ref_name,
2017 mustexist ? RESOLVE_REF_READING : 0,
2018 lock->old_oid.hash, NULL)) {
6294dcb4
JK
2019 if (old_sha1) {
2020 int save_errno = errno;
0568c8e9 2021 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
6294dcb4
JK
2022 errno = save_errno;
2023 return -1;
2024 } else {
c368dde9 2025 oidclr(&lock->old_oid);
6294dcb4
JK
2026 return 0;
2027 }
7bd9bcf3 2028 }
6294dcb4 2029 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
0568c8e9 2030 strbuf_addf(err, "ref '%s' is at %s but expected %s",
7bd9bcf3 2031 lock->ref_name,
c368dde9 2032 oid_to_hex(&lock->old_oid),
7bd9bcf3
MH
2033 sha1_to_hex(old_sha1));
2034 errno = EBUSY;
2035 return -1;
2036 }
2037 return 0;
2038}
2039
2040static int remove_empty_directories(struct strbuf *path)
2041{
2042 /*
2043 * we want to create a file but there is a directory there;
2044 * if that is an empty directory (or a directory that contains
2045 * only empty directories), remove them.
2046 */
2047 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
2048}
2049
3b5d3c98
MH
2050static int create_reflock(const char *path, void *cb)
2051{
2052 struct lock_file *lk = cb;
2053
2054 return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;
2055}
2056
7bd9bcf3
MH
2057/*
2058 * Locks a ref returning the lock on success and NULL on failure.
2059 * On failure errno is set to something meaningful.
2060 */
7eb27cdf
MH
2061static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
2062 const char *refname,
7bd9bcf3
MH
2063 const unsigned char *old_sha1,
2064 const struct string_list *extras,
2065 const struct string_list *skip,
bcb497d0 2066 unsigned int flags, int *type,
7bd9bcf3
MH
2067 struct strbuf *err)
2068{
2069 struct strbuf ref_file = STRBUF_INIT;
7bd9bcf3
MH
2070 struct ref_lock *lock;
2071 int last_errno = 0;
7bd9bcf3 2072 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
7a418f3a 2073 int resolve_flags = RESOLVE_REF_NO_RECURSE;
7a418f3a 2074 int resolved;
7bd9bcf3 2075
32c597e7 2076 files_assert_main_repository(refs, "lock_ref_sha1_basic");
7bd9bcf3
MH
2077 assert(err);
2078
2079 lock = xcalloc(1, sizeof(struct ref_lock));
2080
2081 if (mustexist)
2082 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 2083 if (flags & REF_DELETING)
7bd9bcf3 2084 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
7bd9bcf3 2085
19e02f4f 2086 files_ref_path(refs, &ref_file, refname);
7a418f3a
MH
2087 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2088 lock->old_oid.hash, type);
2089 if (!resolved && errno == EISDIR) {
7bd9bcf3
MH
2090 /*
2091 * we are trying to lock foo but we used to
2092 * have foo/bar which now does not exist;
2093 * it is normal for the empty directory 'foo'
2094 * to remain.
2095 */
7a418f3a 2096 if (remove_empty_directories(&ref_file)) {
7bd9bcf3 2097 last_errno = errno;
00eebe35
MH
2098 if (!verify_refname_available_dir(
2099 refname, extras, skip,
2100 get_loose_refs(refs), err))
7bd9bcf3 2101 strbuf_addf(err, "there are still refs under '%s'",
7a418f3a 2102 refname);
7bd9bcf3
MH
2103 goto error_return;
2104 }
7a418f3a
MH
2105 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2106 lock->old_oid.hash, type);
7bd9bcf3 2107 }
7a418f3a 2108 if (!resolved) {
7bd9bcf3
MH
2109 last_errno = errno;
2110 if (last_errno != ENOTDIR ||
00eebe35
MH
2111 !verify_refname_available_dir(
2112 refname, extras, skip,
2113 get_loose_refs(refs), err))
0568c8e9 2114 strbuf_addf(err, "unable to resolve reference '%s': %s",
7a418f3a 2115 refname, strerror(last_errno));
7bd9bcf3
MH
2116
2117 goto error_return;
2118 }
2859dcd4 2119
7bd9bcf3
MH
2120 /*
2121 * If the ref did not exist and we are creating it, make sure
2122 * there is no existing packed ref whose name begins with our
2123 * refname, nor a packed ref whose name is a proper prefix of
2124 * our refname.
2125 */
2126 if (is_null_oid(&lock->old_oid) &&
2127 verify_refname_available_dir(refname, extras, skip,
00eebe35
MH
2128 get_packed_refs(refs),
2129 err)) {
7bd9bcf3
MH
2130 last_errno = ENOTDIR;
2131 goto error_return;
2132 }
2133
2134 lock->lk = xcalloc(1, sizeof(struct lock_file));
2135
7bd9bcf3 2136 lock->ref_name = xstrdup(refname);
7bd9bcf3 2137
3b5d3c98 2138 if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
7bd9bcf3 2139 last_errno = errno;
3b5d3c98 2140 unable_to_lock_message(ref_file.buf, errno, err);
7bd9bcf3
MH
2141 goto error_return;
2142 }
2143
6294dcb4 2144 if (verify_lock(lock, old_sha1, mustexist, err)) {
7bd9bcf3
MH
2145 last_errno = errno;
2146 goto error_return;
2147 }
2148 goto out;
2149
2150 error_return:
2151 unlock_ref(lock);
2152 lock = NULL;
2153
2154 out:
2155 strbuf_release(&ref_file);
7bd9bcf3
MH
2156 errno = last_errno;
2157 return lock;
2158}
2159
2160/*
2161 * Write an entry to the packed-refs file for the specified refname.
2162 * If peeled is non-NULL, write it as the entry's peeled value.
2163 */
2164static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2165 unsigned char *peeled)
2166{
2167 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2168 if (peeled)
2169 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2170}
2171
2172/*
2173 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2174 */
2175static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2176{
2177 enum peel_status peel_status = peel_entry(entry, 0);
2178
2179 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2180 error("internal error: %s is not a valid packed reference!",
2181 entry->name);
2182 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2183 peel_status == PEEL_PEELED ?
2184 entry->u.value.peeled.hash : NULL);
2185 return 0;
2186}
2187
2188/*
2189 * Lock the packed-refs file for writing. Flags is passed to
2190 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2191 * errno appropriately and return a nonzero value.
2192 */
49c0df6a 2193static int lock_packed_refs(struct files_ref_store *refs, int flags)
7bd9bcf3
MH
2194{
2195 static int timeout_configured = 0;
2196 static int timeout_value = 1000;
7bd9bcf3
MH
2197 struct packed_ref_cache *packed_ref_cache;
2198
32c597e7 2199 files_assert_main_repository(refs, "lock_packed_refs");
49c0df6a 2200
7bd9bcf3
MH
2201 if (!timeout_configured) {
2202 git_config_get_int("core.packedrefstimeout", &timeout_value);
2203 timeout_configured = 1;
2204 }
2205
2206 if (hold_lock_file_for_update_timeout(
33dfb9f3 2207 &packlock, files_packed_refs_path(refs),
7bd9bcf3
MH
2208 flags, timeout_value) < 0)
2209 return -1;
2210 /*
2211 * Get the current packed-refs while holding the lock. If the
2212 * packed-refs file has been modified since we last read it,
2213 * this will automatically invalidate the cache and re-read
2214 * the packed-refs file.
2215 */
00eebe35 2216 packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
2217 packed_ref_cache->lock = &packlock;
2218 /* Increment the reference count to prevent it from being freed: */
2219 acquire_packed_ref_cache(packed_ref_cache);
2220 return 0;
2221}
2222
2223/*
2224 * Write the current version of the packed refs cache from memory to
2225 * disk. The packed-refs file must already be locked for writing (see
2226 * lock_packed_refs()). Return zero on success. On errors, set errno
2227 * and return a nonzero value
2228 */
49c0df6a 2229static int commit_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2230{
2231 struct packed_ref_cache *packed_ref_cache =
00eebe35 2232 get_packed_ref_cache(refs);
7bd9bcf3
MH
2233 int error = 0;
2234 int save_errno = 0;
2235 FILE *out;
2236
32c597e7 2237 files_assert_main_repository(refs, "commit_packed_refs");
49c0df6a 2238
7bd9bcf3
MH
2239 if (!packed_ref_cache->lock)
2240 die("internal error: packed-refs not locked");
2241
2242 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2243 if (!out)
2244 die_errno("unable to fdopen packed-refs descriptor");
2245
2246 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2247 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2248 0, write_packed_entry_fn, out);
2249
2250 if (commit_lock_file(packed_ref_cache->lock)) {
2251 save_errno = errno;
2252 error = -1;
2253 }
2254 packed_ref_cache->lock = NULL;
2255 release_packed_ref_cache(packed_ref_cache);
2256 errno = save_errno;
2257 return error;
2258}
2259
2260/*
2261 * Rollback the lockfile for the packed-refs file, and discard the
2262 * in-memory packed reference cache. (The packed-refs file will be
2263 * read anew if it is needed again after this function is called.)
2264 */
49c0df6a 2265static void rollback_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2266{
2267 struct packed_ref_cache *packed_ref_cache =
00eebe35 2268 get_packed_ref_cache(refs);
7bd9bcf3 2269
32c597e7 2270 files_assert_main_repository(refs, "rollback_packed_refs");
7bd9bcf3
MH
2271
2272 if (!packed_ref_cache->lock)
2273 die("internal error: packed-refs not locked");
2274 rollback_lock_file(packed_ref_cache->lock);
2275 packed_ref_cache->lock = NULL;
2276 release_packed_ref_cache(packed_ref_cache);
00eebe35 2277 clear_packed_ref_cache(refs);
7bd9bcf3
MH
2278}
2279
2280struct ref_to_prune {
2281 struct ref_to_prune *next;
2282 unsigned char sha1[20];
2283 char name[FLEX_ARRAY];
2284};
2285
2286struct pack_refs_cb_data {
2287 unsigned int flags;
2288 struct ref_dir *packed_refs;
2289 struct ref_to_prune *ref_to_prune;
2290};
2291
2292/*
2293 * An each_ref_entry_fn that is run over loose references only. If
2294 * the loose reference can be packed, add an entry in the packed ref
2295 * cache. If the reference should be pruned, also add it to
2296 * ref_to_prune in the pack_refs_cb_data.
2297 */
2298static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2299{
2300 struct pack_refs_cb_data *cb = cb_data;
2301 enum peel_status peel_status;
2302 struct ref_entry *packed_entry;
2303 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2304
2305 /* Do not pack per-worktree refs: */
2306 if (ref_type(entry->name) != REF_TYPE_NORMAL)
2307 return 0;
2308
2309 /* ALWAYS pack tags */
2310 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2311 return 0;
2312
2313 /* Do not pack symbolic or broken refs: */
ffeef642 2314 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))
7bd9bcf3
MH
2315 return 0;
2316
2317 /* Add a packed ref cache entry equivalent to the loose entry. */
2318 peel_status = peel_entry(entry, 1);
2319 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2320 die("internal error peeling reference %s (%s)",
2321 entry->name, oid_to_hex(&entry->u.value.oid));
2322 packed_entry = find_ref(cb->packed_refs, entry->name);
2323 if (packed_entry) {
2324 /* Overwrite existing packed entry with info from loose entry */
2325 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2326 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2327 } else {
2328 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2329 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2330 add_ref(cb->packed_refs, packed_entry);
2331 }
2332 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2333
2334 /* Schedule the loose reference for pruning if requested. */
2335 if ((cb->flags & PACK_REFS_PRUNE)) {
96ffc06f
JK
2336 struct ref_to_prune *n;
2337 FLEX_ALLOC_STR(n, name, entry->name);
7bd9bcf3 2338 hashcpy(n->sha1, entry->u.value.oid.hash);
7bd9bcf3
MH
2339 n->next = cb->ref_to_prune;
2340 cb->ref_to_prune = n;
2341 }
2342 return 0;
2343}
2344
a8f0db2d
MH
2345enum {
2346 REMOVE_EMPTY_PARENTS_REF = 0x01,
2347 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
2348};
2349
7bd9bcf3 2350/*
a8f0db2d
MH
2351 * Remove empty parent directories associated with the specified
2352 * reference and/or its reflog, but spare [logs/]refs/ and immediate
2353 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
2354 * REMOVE_EMPTY_PARENTS_REFLOG.
7bd9bcf3 2355 */
802de3da
NTND
2356static void try_remove_empty_parents(struct files_ref_store *refs,
2357 const char *refname,
2358 unsigned int flags)
7bd9bcf3 2359{
8bdaecb4 2360 struct strbuf buf = STRBUF_INIT;
e9dcc305 2361 struct strbuf sb = STRBUF_INIT;
7bd9bcf3
MH
2362 char *p, *q;
2363 int i;
8bdaecb4
MH
2364
2365 strbuf_addstr(&buf, refname);
2366 p = buf.buf;
7bd9bcf3
MH
2367 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2368 while (*p && *p != '/')
2369 p++;
2370 /* tolerate duplicate slashes; see check_refname_format() */
2371 while (*p == '/')
2372 p++;
2373 }
8bdaecb4 2374 q = buf.buf + buf.len;
a8f0db2d 2375 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
7bd9bcf3
MH
2376 while (q > p && *q != '/')
2377 q--;
2378 while (q > p && *(q-1) == '/')
2379 q--;
2380 if (q == p)
2381 break;
8bdaecb4 2382 strbuf_setlen(&buf, q - buf.buf);
e9dcc305
NTND
2383
2384 strbuf_reset(&sb);
19e02f4f 2385 files_ref_path(refs, &sb, buf.buf);
e9dcc305 2386 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
a8f0db2d 2387 flags &= ~REMOVE_EMPTY_PARENTS_REF;
e9dcc305
NTND
2388
2389 strbuf_reset(&sb);
802de3da 2390 files_reflog_path(refs, &sb, buf.buf);
e9dcc305 2391 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
a8f0db2d 2392 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
7bd9bcf3 2393 }
8bdaecb4 2394 strbuf_release(&buf);
e9dcc305 2395 strbuf_release(&sb);
7bd9bcf3
MH
2396}
2397
2398/* make sure nobody touched the ref, and unlink */
2399static void prune_ref(struct ref_to_prune *r)
2400{
2401 struct ref_transaction *transaction;
2402 struct strbuf err = STRBUF_INIT;
2403
2404 if (check_refname_format(r->name, 0))
2405 return;
2406
2407 transaction = ref_transaction_begin(&err);
2408 if (!transaction ||
2409 ref_transaction_delete(transaction, r->name, r->sha1,
c52ce248 2410 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
7bd9bcf3
MH
2411 ref_transaction_commit(transaction, &err)) {
2412 ref_transaction_free(transaction);
2413 error("%s", err.buf);
2414 strbuf_release(&err);
2415 return;
2416 }
2417 ref_transaction_free(transaction);
2418 strbuf_release(&err);
7bd9bcf3
MH
2419}
2420
2421static void prune_refs(struct ref_to_prune *r)
2422{
2423 while (r) {
2424 prune_ref(r);
2425 r = r->next;
2426 }
2427}
2428
8231527e 2429static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
7bd9bcf3 2430{
00eebe35 2431 struct files_ref_store *refs =
9e7ec634
NTND
2432 files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
2433 "pack_refs");
7bd9bcf3
MH
2434 struct pack_refs_cb_data cbdata;
2435
2436 memset(&cbdata, 0, sizeof(cbdata));
2437 cbdata.flags = flags;
2438
49c0df6a 2439 lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
00eebe35 2440 cbdata.packed_refs = get_packed_refs(refs);
7bd9bcf3 2441
00eebe35 2442 do_for_each_entry_in_dir(get_loose_refs(refs), 0,
7bd9bcf3
MH
2443 pack_if_possible_fn, &cbdata);
2444
49c0df6a 2445 if (commit_packed_refs(refs))
7bd9bcf3
MH
2446 die_errno("unable to overwrite old ref-pack file");
2447
2448 prune_refs(cbdata.ref_to_prune);
2449 return 0;
2450}
2451
2452/*
2453 * Rewrite the packed-refs file, omitting any refs listed in
2454 * 'refnames'. On error, leave packed-refs unchanged, write an error
2455 * message to 'err', and return a nonzero value.
2456 *
2457 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2458 */
0a95ac5f
MH
2459static int repack_without_refs(struct files_ref_store *refs,
2460 struct string_list *refnames, struct strbuf *err)
7bd9bcf3
MH
2461{
2462 struct ref_dir *packed;
2463 struct string_list_item *refname;
2464 int ret, needs_repacking = 0, removed = 0;
2465
32c597e7 2466 files_assert_main_repository(refs, "repack_without_refs");
7bd9bcf3
MH
2467 assert(err);
2468
2469 /* Look for a packed ref */
2470 for_each_string_list_item(refname, refnames) {
f0d21efc 2471 if (get_packed_ref(refs, refname->string)) {
7bd9bcf3
MH
2472 needs_repacking = 1;
2473 break;
2474 }
2475 }
2476
2477 /* Avoid locking if we have nothing to do */
2478 if (!needs_repacking)
2479 return 0; /* no refname exists in packed refs */
2480
49c0df6a 2481 if (lock_packed_refs(refs, 0)) {
33dfb9f3 2482 unable_to_lock_message(files_packed_refs_path(refs), errno, err);
7bd9bcf3
MH
2483 return -1;
2484 }
00eebe35 2485 packed = get_packed_refs(refs);
7bd9bcf3
MH
2486
2487 /* Remove refnames from the cache */
2488 for_each_string_list_item(refname, refnames)
2489 if (remove_entry(packed, refname->string) != -1)
2490 removed = 1;
2491 if (!removed) {
2492 /*
2493 * All packed entries disappeared while we were
2494 * acquiring the lock.
2495 */
49c0df6a 2496 rollback_packed_refs(refs);
7bd9bcf3
MH
2497 return 0;
2498 }
2499
2500 /* Write what remains */
49c0df6a 2501 ret = commit_packed_refs(refs);
7bd9bcf3
MH
2502 if (ret)
2503 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2504 strerror(errno));
2505 return ret;
2506}
2507
a27dcf89
DT
2508static int files_delete_refs(struct ref_store *ref_store,
2509 struct string_list *refnames, unsigned int flags)
7bd9bcf3 2510{
0a95ac5f 2511 struct files_ref_store *refs =
9e7ec634 2512 files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
7bd9bcf3
MH
2513 struct strbuf err = STRBUF_INIT;
2514 int i, result = 0;
2515
2516 if (!refnames->nr)
2517 return 0;
2518
0a95ac5f 2519 result = repack_without_refs(refs, refnames, &err);
7bd9bcf3
MH
2520 if (result) {
2521 /*
2522 * If we failed to rewrite the packed-refs file, then
2523 * it is unsafe to try to remove loose refs, because
2524 * doing so might expose an obsolete packed value for
2525 * a reference that might even point at an object that
2526 * has been garbage collected.
2527 */
2528 if (refnames->nr == 1)
2529 error(_("could not delete reference %s: %s"),
2530 refnames->items[0].string, err.buf);
2531 else
2532 error(_("could not delete references: %s"), err.buf);
2533
2534 goto out;
2535 }
2536
2537 for (i = 0; i < refnames->nr; i++) {
2538 const char *refname = refnames->items[i].string;
2539
755b49ae 2540 if (delete_ref(NULL, refname, NULL, flags))
7bd9bcf3
MH
2541 result |= error(_("could not remove reference %s"), refname);
2542 }
2543
2544out:
2545 strbuf_release(&err);
2546 return result;
2547}
2548
2549/*
2550 * People using contrib's git-new-workdir have .git/logs/refs ->
2551 * /some/other/path/.git/logs/refs, and that may live on another device.
2552 *
2553 * IOW, to avoid cross device rename errors, the temporary renamed log must
2554 * live into logs/refs.
2555 */
a5c1efd6 2556#define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
7bd9bcf3 2557
e9dcc305
NTND
2558struct rename_cb {
2559 const char *tmp_renamed_log;
2560 int true_errno;
2561};
2562
2563static int rename_tmp_log_callback(const char *path, void *cb_data)
7bd9bcf3 2564{
e9dcc305 2565 struct rename_cb *cb = cb_data;
7bd9bcf3 2566
e9dcc305 2567 if (rename(cb->tmp_renamed_log, path)) {
6a7f3631
MH
2568 /*
2569 * rename(a, b) when b is an existing directory ought
2570 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
2571 * Sheesh. Record the true errno for error reporting,
2572 * but report EISDIR to raceproof_create_file() so
2573 * that it knows to retry.
2574 */
e9dcc305 2575 cb->true_errno = errno;
6a7f3631
MH
2576 if (errno == ENOTDIR)
2577 errno = EISDIR;
2578 return -1;
2579 } else {
2580 return 0;
7bd9bcf3 2581 }
6a7f3631 2582}
7bd9bcf3 2583
802de3da 2584static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
6a7f3631 2585{
e9dcc305
NTND
2586 struct strbuf path = STRBUF_INIT;
2587 struct strbuf tmp = STRBUF_INIT;
2588 struct rename_cb cb;
2589 int ret;
6a7f3631 2590
802de3da
NTND
2591 files_reflog_path(refs, &path, newrefname);
2592 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
e9dcc305
NTND
2593 cb.tmp_renamed_log = tmp.buf;
2594 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
6a7f3631
MH
2595 if (ret) {
2596 if (errno == EISDIR)
e9dcc305 2597 error("directory not empty: %s", path.buf);
6a7f3631 2598 else
990c98d2 2599 error("unable to move logfile %s to %s: %s",
e9dcc305
NTND
2600 tmp.buf, path.buf,
2601 strerror(cb.true_errno));
7bd9bcf3 2602 }
6a7f3631 2603
e9dcc305
NTND
2604 strbuf_release(&path);
2605 strbuf_release(&tmp);
7bd9bcf3
MH
2606 return ret;
2607}
2608
62665823
MH
2609static int files_verify_refname_available(struct ref_store *ref_store,
2610 const char *newname,
2611 const struct string_list *extras,
2612 const struct string_list *skip,
2613 struct strbuf *err)
7bd9bcf3 2614{
00eebe35 2615 struct files_ref_store *refs =
9e7ec634 2616 files_downcast(ref_store, REF_STORE_READ, "verify_refname_available");
00eebe35
MH
2617 struct ref_dir *packed_refs = get_packed_refs(refs);
2618 struct ref_dir *loose_refs = get_loose_refs(refs);
7bd9bcf3
MH
2619
2620 if (verify_refname_available_dir(newname, extras, skip,
2621 packed_refs, err) ||
2622 verify_refname_available_dir(newname, extras, skip,
2623 loose_refs, err))
2624 return -1;
2625
2626 return 0;
2627}
2628
7bd9bcf3
MH
2629static int write_ref_to_lockfile(struct ref_lock *lock,
2630 const unsigned char *sha1, struct strbuf *err);
f18a7892
MH
2631static int commit_ref_update(struct files_ref_store *refs,
2632 struct ref_lock *lock,
7bd9bcf3 2633 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2634 struct strbuf *err);
7bd9bcf3 2635
9b6b40d9
DT
2636static int files_rename_ref(struct ref_store *ref_store,
2637 const char *oldrefname, const char *newrefname,
2638 const char *logmsg)
7bd9bcf3 2639{
9b6b40d9 2640 struct files_ref_store *refs =
9e7ec634 2641 files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
7bd9bcf3
MH
2642 unsigned char sha1[20], orig_sha1[20];
2643 int flag = 0, logmoved = 0;
2644 struct ref_lock *lock;
2645 struct stat loginfo;
e9dcc305
NTND
2646 struct strbuf sb_oldref = STRBUF_INIT;
2647 struct strbuf sb_newref = STRBUF_INIT;
2648 struct strbuf tmp_renamed_log = STRBUF_INIT;
2649 int log, ret;
7bd9bcf3
MH
2650 struct strbuf err = STRBUF_INIT;
2651
802de3da
NTND
2652 files_reflog_path(refs, &sb_oldref, oldrefname);
2653 files_reflog_path(refs, &sb_newref, newrefname);
2654 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
e9dcc305
NTND
2655
2656 log = !lstat(sb_oldref.buf, &loginfo);
0a3f07d6
NTND
2657 if (log && S_ISLNK(loginfo.st_mode)) {
2658 ret = error("reflog for %s is a symlink", oldrefname);
2659 goto out;
2660 }
7bd9bcf3 2661
12fd3496 2662 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
0a3f07d6
NTND
2663 orig_sha1, &flag)) {
2664 ret = error("refname %s not found", oldrefname);
2665 goto out;
2666 }
e711b1af 2667
0a3f07d6
NTND
2668 if (flag & REF_ISSYMREF) {
2669 ret = error("refname %s is a symbolic ref, renaming it is not supported",
2670 oldrefname);
2671 goto out;
2672 }
2673 if (!rename_ref_available(oldrefname, newrefname)) {
2674 ret = 1;
2675 goto out;
2676 }
7bd9bcf3 2677
e9dcc305 2678 if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
a5c1efd6 2679 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
0a3f07d6
NTND
2680 oldrefname, strerror(errno));
2681 goto out;
2682 }
7bd9bcf3 2683
893dbf5b 2684 if (delete_ref(logmsg, oldrefname, orig_sha1, REF_NODEREF)) {
7bd9bcf3
MH
2685 error("unable to delete old %s", oldrefname);
2686 goto rollback;
2687 }
2688
12fd3496
DT
2689 /*
2690 * Since we are doing a shallow lookup, sha1 is not the
2691 * correct value to pass to delete_ref as old_sha1. But that
2692 * doesn't matter, because an old_sha1 check wouldn't add to
2693 * the safety anyway; we want to delete the reference whatever
2694 * its current value.
2695 */
2696 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2697 sha1, NULL) &&
755b49ae 2698 delete_ref(NULL, newrefname, NULL, REF_NODEREF)) {
58364324 2699 if (errno == EISDIR) {
7bd9bcf3
MH
2700 struct strbuf path = STRBUF_INIT;
2701 int result;
2702
19e02f4f 2703 files_ref_path(refs, &path, newrefname);
7bd9bcf3
MH
2704 result = remove_empty_directories(&path);
2705 strbuf_release(&path);
2706
2707 if (result) {
2708 error("Directory not empty: %s", newrefname);
2709 goto rollback;
2710 }
2711 } else {
2712 error("unable to delete existing %s", newrefname);
2713 goto rollback;
2714 }
2715 }
2716
802de3da 2717 if (log && rename_tmp_log(refs, newrefname))
7bd9bcf3
MH
2718 goto rollback;
2719
2720 logmoved = log;
2721
7eb27cdf
MH
2722 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
2723 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
2724 if (!lock) {
2725 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2726 strbuf_release(&err);
2727 goto rollback;
2728 }
2729 hashcpy(lock->old_oid.hash, orig_sha1);
2730
2731 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 2732 commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {
7bd9bcf3
MH
2733 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
2734 strbuf_release(&err);
2735 goto rollback;
2736 }
2737
0a3f07d6
NTND
2738 ret = 0;
2739 goto out;
7bd9bcf3
MH
2740
2741 rollback:
7eb27cdf
MH
2742 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
2743 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
2744 if (!lock) {
2745 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2746 strbuf_release(&err);
2747 goto rollbacklog;
2748 }
2749
2750 flag = log_all_ref_updates;
341fb286 2751 log_all_ref_updates = LOG_REFS_NONE;
7bd9bcf3 2752 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 2753 commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {
7bd9bcf3
MH
2754 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
2755 strbuf_release(&err);
2756 }
2757 log_all_ref_updates = flag;
2758
2759 rollbacklog:
e9dcc305 2760 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
7bd9bcf3
MH
2761 error("unable to restore logfile %s from %s: %s",
2762 oldrefname, newrefname, strerror(errno));
2763 if (!logmoved && log &&
e9dcc305 2764 rename(tmp_renamed_log.buf, sb_oldref.buf))
a5c1efd6 2765 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
7bd9bcf3 2766 oldrefname, strerror(errno));
0a3f07d6
NTND
2767 ret = 1;
2768 out:
e9dcc305
NTND
2769 strbuf_release(&sb_newref);
2770 strbuf_release(&sb_oldref);
2771 strbuf_release(&tmp_renamed_log);
2772
0a3f07d6 2773 return ret;
7bd9bcf3
MH
2774}
2775
2776static int close_ref(struct ref_lock *lock)
2777{
2778 if (close_lock_file(lock->lk))
2779 return -1;
2780 return 0;
2781}
2782
2783static int commit_ref(struct ref_lock *lock)
2784{
5387c0d8
MH
2785 char *path = get_locked_file_path(lock->lk);
2786 struct stat st;
2787
2788 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
2789 /*
2790 * There is a directory at the path we want to rename
2791 * the lockfile to. Hopefully it is empty; try to
2792 * delete it.
2793 */
2794 size_t len = strlen(path);
2795 struct strbuf sb_path = STRBUF_INIT;
2796
2797 strbuf_attach(&sb_path, path, len, len);
2798
2799 /*
2800 * If this fails, commit_lock_file() will also fail
2801 * and will report the problem.
2802 */
2803 remove_empty_directories(&sb_path);
2804 strbuf_release(&sb_path);
2805 } else {
2806 free(path);
2807 }
2808
7bd9bcf3
MH
2809 if (commit_lock_file(lock->lk))
2810 return -1;
2811 return 0;
2812}
2813
1fb0c809
MH
2814static int open_or_create_logfile(const char *path, void *cb)
2815{
2816 int *fd = cb;
2817
2818 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
2819 return (*fd < 0) ? -1 : 0;
2820}
2821
7bd9bcf3 2822/*
4533e534
MH
2823 * Create a reflog for a ref. If force_create = 0, only create the
2824 * reflog for certain refs (those for which should_autocreate_reflog
2825 * returns non-zero). Otherwise, create it regardless of the reference
2826 * name. If the logfile already existed or was created, return 0 and
2827 * set *logfd to the file descriptor opened for appending to the file.
2828 * If no logfile exists and we decided not to create one, return 0 and
2829 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
2830 * return -1.
7bd9bcf3 2831 */
802de3da
NTND
2832static int log_ref_setup(struct files_ref_store *refs,
2833 const char *refname, int force_create,
4533e534 2834 int *logfd, struct strbuf *err)
7bd9bcf3 2835{
802de3da
NTND
2836 struct strbuf logfile_sb = STRBUF_INIT;
2837 char *logfile;
2838
2839 files_reflog_path(refs, &logfile_sb, refname);
2840 logfile = strbuf_detach(&logfile_sb, NULL);
7bd9bcf3 2841
7bd9bcf3 2842 if (force_create || should_autocreate_reflog(refname)) {
4533e534 2843 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1fb0c809
MH
2844 if (errno == ENOENT)
2845 strbuf_addf(err, "unable to create directory for '%s': "
4533e534 2846 "%s", logfile, strerror(errno));
1fb0c809
MH
2847 else if (errno == EISDIR)
2848 strbuf_addf(err, "there are still logs under '%s'",
4533e534 2849 logfile);
1fb0c809 2850 else
854bda6b 2851 strbuf_addf(err, "unable to append to '%s': %s",
4533e534 2852 logfile, strerror(errno));
7bd9bcf3 2853
4533e534 2854 goto error;
7bd9bcf3 2855 }
854bda6b 2856 } else {
4533e534 2857 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
e404f459 2858 if (*logfd < 0) {
854bda6b
MH
2859 if (errno == ENOENT || errno == EISDIR) {
2860 /*
2861 * The logfile doesn't already exist,
2862 * but that is not an error; it only
2863 * means that we won't write log
2864 * entries to it.
2865 */
2866 ;
2867 } else {
2868 strbuf_addf(err, "unable to append to '%s': %s",
4533e534
MH
2869 logfile, strerror(errno));
2870 goto error;
854bda6b 2871 }
7bd9bcf3
MH
2872 }
2873 }
2874
e404f459 2875 if (*logfd >= 0)
4533e534 2876 adjust_shared_perm(logfile);
854bda6b 2877
4533e534 2878 free(logfile);
7bd9bcf3 2879 return 0;
7bd9bcf3 2880
4533e534
MH
2881error:
2882 free(logfile);
2883 return -1;
7bd9bcf3 2884}
7bd9bcf3 2885
e3688bd6
DT
2886static int files_create_reflog(struct ref_store *ref_store,
2887 const char *refname, int force_create,
2888 struct strbuf *err)
7bd9bcf3 2889{
802de3da 2890 struct files_ref_store *refs =
9e7ec634 2891 files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
e404f459 2892 int fd;
7bd9bcf3 2893
802de3da 2894 if (log_ref_setup(refs, refname, force_create, &fd, err))
4533e534
MH
2895 return -1;
2896
e404f459
MH
2897 if (fd >= 0)
2898 close(fd);
4533e534
MH
2899
2900 return 0;
7bd9bcf3
MH
2901}
2902
2903static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2904 const unsigned char *new_sha1,
2905 const char *committer, const char *msg)
2906{
2907 int msglen, written;
2908 unsigned maxlen, len;
2909 char *logrec;
2910
2911 msglen = msg ? strlen(msg) : 0;
2912 maxlen = strlen(committer) + msglen + 100;
2913 logrec = xmalloc(maxlen);
2914 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2915 sha1_to_hex(old_sha1),
2916 sha1_to_hex(new_sha1),
2917 committer);
2918 if (msglen)
2919 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2920
2921 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2922 free(logrec);
2923 if (written != len)
2924 return -1;
2925
2926 return 0;
2927}
2928
802de3da
NTND
2929static int files_log_ref_write(struct files_ref_store *refs,
2930 const char *refname, const unsigned char *old_sha1,
11f8457f
NTND
2931 const unsigned char *new_sha1, const char *msg,
2932 int flags, struct strbuf *err)
7bd9bcf3 2933{
e404f459 2934 int logfd, result;
7bd9bcf3 2935
341fb286
CW
2936 if (log_all_ref_updates == LOG_REFS_UNSET)
2937 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
7bd9bcf3 2938
802de3da
NTND
2939 result = log_ref_setup(refs, refname,
2940 flags & REF_FORCE_CREATE_REFLOG,
4533e534 2941 &logfd, err);
7bd9bcf3
MH
2942
2943 if (result)
2944 return result;
2945
7bd9bcf3
MH
2946 if (logfd < 0)
2947 return 0;
2948 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2949 git_committer_info(0), msg);
2950 if (result) {
e9dcc305 2951 struct strbuf sb = STRBUF_INIT;
87b21e05
MH
2952 int save_errno = errno;
2953
802de3da 2954 files_reflog_path(refs, &sb, refname);
87b21e05 2955 strbuf_addf(err, "unable to append to '%s': %s",
e9dcc305
NTND
2956 sb.buf, strerror(save_errno));
2957 strbuf_release(&sb);
7bd9bcf3
MH
2958 close(logfd);
2959 return -1;
2960 }
2961 if (close(logfd)) {
e9dcc305 2962 struct strbuf sb = STRBUF_INIT;
87b21e05
MH
2963 int save_errno = errno;
2964
802de3da 2965 files_reflog_path(refs, &sb, refname);
87b21e05 2966 strbuf_addf(err, "unable to append to '%s': %s",
e9dcc305
NTND
2967 sb.buf, strerror(save_errno));
2968 strbuf_release(&sb);
7bd9bcf3
MH
2969 return -1;
2970 }
2971 return 0;
2972}
2973
7bd9bcf3
MH
2974/*
2975 * Write sha1 into the open lockfile, then close the lockfile. On
2976 * errors, rollback the lockfile, fill in *err and
2977 * return -1.
2978 */
2979static int write_ref_to_lockfile(struct ref_lock *lock,
2980 const unsigned char *sha1, struct strbuf *err)
2981{
2982 static char term = '\n';
2983 struct object *o;
2984 int fd;
2985
2986 o = parse_object(sha1);
2987 if (!o) {
2988 strbuf_addf(err,
0568c8e9 2989 "trying to write ref '%s' with nonexistent object %s",
7bd9bcf3
MH
2990 lock->ref_name, sha1_to_hex(sha1));
2991 unlock_ref(lock);
2992 return -1;
2993 }
2994 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2995 strbuf_addf(err,
0568c8e9 2996 "trying to write non-commit object %s to branch '%s'",
7bd9bcf3
MH
2997 sha1_to_hex(sha1), lock->ref_name);
2998 unlock_ref(lock);
2999 return -1;
3000 }
3001 fd = get_lock_file_fd(lock->lk);
3002 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
3003 write_in_full(fd, &term, 1) != 1 ||
3004 close_ref(lock) < 0) {
3005 strbuf_addf(err,
0568c8e9 3006 "couldn't write '%s'", get_lock_file_path(lock->lk));
7bd9bcf3
MH
3007 unlock_ref(lock);
3008 return -1;
3009 }
3010 return 0;
3011}
3012
3013/*
3014 * Commit a change to a loose reference that has already been written
3015 * to the loose reference lockfile. Also update the reflogs if
3016 * necessary, using the specified lockmsg (which can be NULL).
3017 */
f18a7892
MH
3018static int commit_ref_update(struct files_ref_store *refs,
3019 struct ref_lock *lock,
7bd9bcf3 3020 const unsigned char *sha1, const char *logmsg,
5d9b2de4 3021 struct strbuf *err)
7bd9bcf3 3022{
32c597e7 3023 files_assert_main_repository(refs, "commit_ref_update");
00eebe35
MH
3024
3025 clear_loose_ref_cache(refs);
802de3da
NTND
3026 if (files_log_ref_write(refs, lock->ref_name,
3027 lock->old_oid.hash, sha1,
81b1b6d4 3028 logmsg, 0, err)) {
7bd9bcf3 3029 char *old_msg = strbuf_detach(err, NULL);
0568c8e9 3030 strbuf_addf(err, "cannot update the ref '%s': %s",
7bd9bcf3
MH
3031 lock->ref_name, old_msg);
3032 free(old_msg);
3033 unlock_ref(lock);
3034 return -1;
3035 }
7a418f3a
MH
3036
3037 if (strcmp(lock->ref_name, "HEAD") != 0) {
7bd9bcf3
MH
3038 /*
3039 * Special hack: If a branch is updated directly and HEAD
3040 * points to it (may happen on the remote side of a push
3041 * for example) then logically the HEAD reflog should be
3042 * updated too.
3043 * A generic solution implies reverse symref information,
3044 * but finding all symrefs pointing to the given branch
3045 * would be rather costly for this rare event (the direct
3046 * update of a branch) to be worth it. So let's cheat and
3047 * check with HEAD only which should cover 99% of all usage
3048 * scenarios (even 100% of the default ones).
3049 */
3050 unsigned char head_sha1[20];
3051 int head_flag;
3052 const char *head_ref;
7a418f3a 3053
7bd9bcf3
MH
3054 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3055 head_sha1, &head_flag);
3056 if (head_ref && (head_flag & REF_ISSYMREF) &&
3057 !strcmp(head_ref, lock->ref_name)) {
3058 struct strbuf log_err = STRBUF_INIT;
802de3da
NTND
3059 if (files_log_ref_write(refs, "HEAD",
3060 lock->old_oid.hash, sha1,
3061 logmsg, 0, &log_err)) {
7bd9bcf3
MH
3062 error("%s", log_err.buf);
3063 strbuf_release(&log_err);
3064 }
3065 }
3066 }
7a418f3a 3067
7bd9bcf3 3068 if (commit_ref(lock)) {
0568c8e9 3069 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
7bd9bcf3
MH
3070 unlock_ref(lock);
3071 return -1;
3072 }
3073
3074 unlock_ref(lock);
3075 return 0;
3076}
3077
370e5ad6 3078static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 3079{
370e5ad6 3080 int ret = -1;
7bd9bcf3 3081#ifndef NO_SYMLINK_HEAD
370e5ad6
JK
3082 char *ref_path = get_locked_file_path(lock->lk);
3083 unlink(ref_path);
3084 ret = symlink(target, ref_path);
3085 free(ref_path);
3086
3087 if (ret)
7bd9bcf3 3088 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 3089#endif
370e5ad6
JK
3090 return ret;
3091}
7bd9bcf3 3092
802de3da
NTND
3093static void update_symref_reflog(struct files_ref_store *refs,
3094 struct ref_lock *lock, const char *refname,
370e5ad6
JK
3095 const char *target, const char *logmsg)
3096{
3097 struct strbuf err = STRBUF_INIT;
3098 unsigned char new_sha1[20];
b9badadd 3099 if (logmsg && !read_ref(target, new_sha1) &&
802de3da
NTND
3100 files_log_ref_write(refs, refname, lock->old_oid.hash,
3101 new_sha1, logmsg, 0, &err)) {
7bd9bcf3
MH
3102 error("%s", err.buf);
3103 strbuf_release(&err);
3104 }
370e5ad6 3105}
7bd9bcf3 3106
802de3da
NTND
3107static int create_symref_locked(struct files_ref_store *refs,
3108 struct ref_lock *lock, const char *refname,
370e5ad6
JK
3109 const char *target, const char *logmsg)
3110{
3111 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
802de3da 3112 update_symref_reflog(refs, lock, refname, target, logmsg);
370e5ad6
JK
3113 return 0;
3114 }
3115
3116 if (!fdopen_lock_file(lock->lk, "w"))
3117 return error("unable to fdopen %s: %s",
3118 lock->lk->tempfile.filename.buf, strerror(errno));
3119
802de3da 3120 update_symref_reflog(refs, lock, refname, target, logmsg);
396da8f7 3121
370e5ad6
JK
3122 /* no error check; commit_ref will check ferror */
3123 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
3124 if (commit_ref(lock) < 0)
3125 return error("unable to write symref for %s: %s", refname,
3126 strerror(errno));
7bd9bcf3
MH
3127 return 0;
3128}
3129
284689ba
MH
3130static int files_create_symref(struct ref_store *ref_store,
3131 const char *refname, const char *target,
3132 const char *logmsg)
370e5ad6 3133{
7eb27cdf 3134 struct files_ref_store *refs =
9e7ec634 3135 files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
370e5ad6
JK
3136 struct strbuf err = STRBUF_INIT;
3137 struct ref_lock *lock;
3138 int ret;
3139
7eb27cdf
MH
3140 lock = lock_ref_sha1_basic(refs, refname, NULL,
3141 NULL, NULL, REF_NODEREF, NULL,
370e5ad6
JK
3142 &err);
3143 if (!lock) {
3144 error("%s", err.buf);
3145 strbuf_release(&err);
3146 return -1;
3147 }
3148
802de3da 3149 ret = create_symref_locked(refs, lock, refname, target, logmsg);
370e5ad6
JK
3150 unlock_ref(lock);
3151 return ret;
3152}
3153
39ee4c6c 3154int set_worktree_head_symref(const char *gitdir, const char *target, const char *logmsg)
2233066e 3155{
802de3da
NTND
3156 /*
3157 * FIXME: this obviously will not work well for future refs
3158 * backends. This function needs to die.
3159 */
3160 struct files_ref_store *refs =
9e7ec634
NTND
3161 files_downcast(get_main_ref_store(),
3162 REF_STORE_WRITE,
3163 "set_head_symref");
802de3da 3164
2233066e
KY
3165 static struct lock_file head_lock;
3166 struct ref_lock *lock;
2233066e
KY
3167 struct strbuf head_path = STRBUF_INIT;
3168 const char *head_rel;
3169 int ret;
3170
3171 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));
3172 if (hold_lock_file_for_update(&head_lock, head_path.buf,
3173 LOCK_NO_DEREF) < 0) {
18eb3a9c
KY
3174 struct strbuf err = STRBUF_INIT;
3175 unable_to_lock_message(head_path.buf, errno, &err);
2233066e
KY
3176 error("%s", err.buf);
3177 strbuf_release(&err);
3178 strbuf_release(&head_path);
3179 return -1;
3180 }
3181
3182 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for
3183 linked trees */
3184 head_rel = remove_leading_path(head_path.buf,
3185 absolute_path(get_git_common_dir()));
3186 /* to make use of create_symref_locked(), initialize ref_lock */
3187 lock = xcalloc(1, sizeof(struct ref_lock));
3188 lock->lk = &head_lock;
3189 lock->ref_name = xstrdup(head_rel);
2233066e 3190
802de3da 3191 ret = create_symref_locked(refs, lock, head_rel, target, logmsg);
2233066e
KY
3192
3193 unlock_ref(lock); /* will free lock */
3194 strbuf_release(&head_path);
3195 return ret;
3196}
3197
e3688bd6
DT
3198static int files_reflog_exists(struct ref_store *ref_store,
3199 const char *refname)
7bd9bcf3 3200{
802de3da 3201 struct files_ref_store *refs =
9e7ec634 3202 files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
e9dcc305 3203 struct strbuf sb = STRBUF_INIT;
7bd9bcf3 3204 struct stat st;
e9dcc305 3205 int ret;
7bd9bcf3 3206
802de3da 3207 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3208 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
3209 strbuf_release(&sb);
3210 return ret;
7bd9bcf3
MH
3211}
3212
e3688bd6
DT
3213static int files_delete_reflog(struct ref_store *ref_store,
3214 const char *refname)
7bd9bcf3 3215{
802de3da 3216 struct files_ref_store *refs =
9e7ec634 3217 files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
e9dcc305
NTND
3218 struct strbuf sb = STRBUF_INIT;
3219 int ret;
3220
802de3da 3221 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3222 ret = remove_path(sb.buf);
3223 strbuf_release(&sb);
3224 return ret;
7bd9bcf3
MH
3225}
3226
3227static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3228{
9461d272 3229 struct object_id ooid, noid;
7bd9bcf3
MH
3230 char *email_end, *message;
3231 unsigned long timestamp;
3232 int tz;
43bc3b6c 3233 const char *p = sb->buf;
7bd9bcf3
MH
3234
3235 /* old SP new SP name <email> SP time TAB msg LF */
43bc3b6c 3236 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
3237 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
3238 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
3239 !(email_end = strchr(p, '>')) ||
7bd9bcf3
MH
3240 email_end[1] != ' ' ||
3241 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3242 !message || message[0] != ' ' ||
3243 (message[1] != '+' && message[1] != '-') ||
3244 !isdigit(message[2]) || !isdigit(message[3]) ||
3245 !isdigit(message[4]) || !isdigit(message[5]))
3246 return 0; /* corrupt? */
3247 email_end[1] = '\0';
3248 tz = strtol(message + 1, NULL, 10);
3249 if (message[6] != '\t')
3250 message += 6;
3251 else
3252 message += 7;
43bc3b6c 3253 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
7bd9bcf3
MH
3254}
3255
3256static char *find_beginning_of_line(char *bob, char *scan)
3257{
3258 while (bob < scan && *(--scan) != '\n')
3259 ; /* keep scanning backwards */
3260 /*
3261 * Return either beginning of the buffer, or LF at the end of
3262 * the previous line.
3263 */
3264 return scan;
3265}
3266
e3688bd6
DT
3267static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
3268 const char *refname,
3269 each_reflog_ent_fn fn,
3270 void *cb_data)
7bd9bcf3 3271{
802de3da 3272 struct files_ref_store *refs =
9e7ec634
NTND
3273 files_downcast(ref_store, REF_STORE_READ,
3274 "for_each_reflog_ent_reverse");
7bd9bcf3
MH
3275 struct strbuf sb = STRBUF_INIT;
3276 FILE *logfp;
3277 long pos;
3278 int ret = 0, at_tail = 1;
3279
802de3da 3280 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3281 logfp = fopen(sb.buf, "r");
3282 strbuf_release(&sb);
7bd9bcf3
MH
3283 if (!logfp)
3284 return -1;
3285
3286 /* Jump to the end */
3287 if (fseek(logfp, 0, SEEK_END) < 0)
3288 return error("cannot seek back reflog for %s: %s",
3289 refname, strerror(errno));
3290 pos = ftell(logfp);
3291 while (!ret && 0 < pos) {
3292 int cnt;
3293 size_t nread;
3294 char buf[BUFSIZ];
3295 char *endp, *scanp;
3296
3297 /* Fill next block from the end */
3298 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3299 if (fseek(logfp, pos - cnt, SEEK_SET))
3300 return error("cannot seek back reflog for %s: %s",
3301 refname, strerror(errno));
3302 nread = fread(buf, cnt, 1, logfp);
3303 if (nread != 1)
3304 return error("cannot read %d bytes from reflog for %s: %s",
3305 cnt, refname, strerror(errno));
3306 pos -= cnt;
3307
3308 scanp = endp = buf + cnt;
3309 if (at_tail && scanp[-1] == '\n')
3310 /* Looking at the final LF at the end of the file */
3311 scanp--;
3312 at_tail = 0;
3313
3314 while (buf < scanp) {
3315 /*
3316 * terminating LF of the previous line, or the beginning
3317 * of the buffer.
3318 */
3319 char *bp;
3320
3321 bp = find_beginning_of_line(buf, scanp);
3322
3323 if (*bp == '\n') {
3324 /*
3325 * The newline is the end of the previous line,
3326 * so we know we have complete line starting
3327 * at (bp + 1). Prefix it onto any prior data
3328 * we collected for the line and process it.
3329 */
3330 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3331 scanp = bp;
3332 endp = bp + 1;
3333 ret = show_one_reflog_ent(&sb, fn, cb_data);
3334 strbuf_reset(&sb);
3335 if (ret)
3336 break;
3337 } else if (!pos) {
3338 /*
3339 * We are at the start of the buffer, and the
3340 * start of the file; there is no previous
3341 * line, and we have everything for this one.
3342 * Process it, and we can end the loop.
3343 */
3344 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3345 ret = show_one_reflog_ent(&sb, fn, cb_data);
3346 strbuf_reset(&sb);
3347 break;
3348 }
3349
3350 if (bp == buf) {
3351 /*
3352 * We are at the start of the buffer, and there
3353 * is more file to read backwards. Which means
3354 * we are in the middle of a line. Note that we
3355 * may get here even if *bp was a newline; that
3356 * just means we are at the exact end of the
3357 * previous line, rather than some spot in the
3358 * middle.
3359 *
3360 * Save away what we have to be combined with
3361 * the data from the next read.
3362 */
3363 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3364 break;
3365 }
3366 }
3367
3368 }
3369 if (!ret && sb.len)
3370 die("BUG: reverse reflog parser had leftover data");
3371
3372 fclose(logfp);
3373 strbuf_release(&sb);
3374 return ret;
3375}
3376
e3688bd6
DT
3377static int files_for_each_reflog_ent(struct ref_store *ref_store,
3378 const char *refname,
3379 each_reflog_ent_fn fn, void *cb_data)
7bd9bcf3 3380{
802de3da 3381 struct files_ref_store *refs =
9e7ec634
NTND
3382 files_downcast(ref_store, REF_STORE_READ,
3383 "for_each_reflog_ent");
7bd9bcf3
MH
3384 FILE *logfp;
3385 struct strbuf sb = STRBUF_INIT;
3386 int ret = 0;
3387
802de3da 3388 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3389 logfp = fopen(sb.buf, "r");
3390 strbuf_release(&sb);
7bd9bcf3
MH
3391 if (!logfp)
3392 return -1;
3393
3394 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3395 ret = show_one_reflog_ent(&sb, fn, cb_data);
3396 fclose(logfp);
3397 strbuf_release(&sb);
3398 return ret;
3399}
7bd9bcf3 3400
2880d16f
MH
3401struct files_reflog_iterator {
3402 struct ref_iterator base;
7bd9bcf3 3403
2880d16f
MH
3404 struct dir_iterator *dir_iterator;
3405 struct object_id oid;
3406};
7bd9bcf3 3407
2880d16f
MH
3408static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
3409{
3410 struct files_reflog_iterator *iter =
3411 (struct files_reflog_iterator *)ref_iterator;
3412 struct dir_iterator *diter = iter->dir_iterator;
3413 int ok;
3414
3415 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
3416 int flags;
3417
3418 if (!S_ISREG(diter->st.st_mode))
7bd9bcf3 3419 continue;
2880d16f
MH
3420 if (diter->basename[0] == '.')
3421 continue;
3422 if (ends_with(diter->basename, ".lock"))
7bd9bcf3 3423 continue;
7bd9bcf3 3424
2880d16f
MH
3425 if (read_ref_full(diter->relative_path, 0,
3426 iter->oid.hash, &flags)) {
3427 error("bad ref for %s", diter->path.buf);
3428 continue;
7bd9bcf3 3429 }
2880d16f
MH
3430
3431 iter->base.refname = diter->relative_path;
3432 iter->base.oid = &iter->oid;
3433 iter->base.flags = flags;
3434 return ITER_OK;
7bd9bcf3 3435 }
2880d16f
MH
3436
3437 iter->dir_iterator = NULL;
3438 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
3439 ok = ITER_ERROR;
3440 return ok;
3441}
3442
3443static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
3444 struct object_id *peeled)
3445{
3446 die("BUG: ref_iterator_peel() called for reflog_iterator");
3447}
3448
3449static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
3450{
3451 struct files_reflog_iterator *iter =
3452 (struct files_reflog_iterator *)ref_iterator;
3453 int ok = ITER_DONE;
3454
3455 if (iter->dir_iterator)
3456 ok = dir_iterator_abort(iter->dir_iterator);
3457
3458 base_ref_iterator_free(ref_iterator);
3459 return ok;
3460}
3461
3462static struct ref_iterator_vtable files_reflog_iterator_vtable = {
3463 files_reflog_iterator_advance,
3464 files_reflog_iterator_peel,
3465 files_reflog_iterator_abort
3466};
3467
e3688bd6 3468static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2880d16f 3469{
802de3da 3470 struct files_ref_store *refs =
9e7ec634
NTND
3471 files_downcast(ref_store, REF_STORE_READ,
3472 "reflog_iterator_begin");
2880d16f
MH
3473 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
3474 struct ref_iterator *ref_iterator = &iter->base;
e9dcc305 3475 struct strbuf sb = STRBUF_INIT;
2880d16f
MH
3476
3477 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
802de3da 3478 files_reflog_path(refs, &sb, NULL);
e9dcc305
NTND
3479 iter->dir_iterator = dir_iterator_begin(sb.buf);
3480 strbuf_release(&sb);
2880d16f 3481 return ref_iterator;
7bd9bcf3
MH
3482}
3483
7bd9bcf3
MH
3484static int ref_update_reject_duplicates(struct string_list *refnames,
3485 struct strbuf *err)
3486{
3487 int i, n = refnames->nr;
3488
3489 assert(err);
3490
3491 for (i = 1; i < n; i++)
3492 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3493 strbuf_addf(err,
0568c8e9 3494 "multiple updates for ref '%s' not allowed.",
7bd9bcf3
MH
3495 refnames->items[i].string);
3496 return 1;
3497 }
3498 return 0;
3499}
3500
165056b2 3501/*
92b1551b
MH
3502 * If update is a direct update of head_ref (the reference pointed to
3503 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
3504 */
3505static int split_head_update(struct ref_update *update,
3506 struct ref_transaction *transaction,
3507 const char *head_ref,
3508 struct string_list *affected_refnames,
3509 struct strbuf *err)
3510{
3511 struct string_list_item *item;
3512 struct ref_update *new_update;
3513
3514 if ((update->flags & REF_LOG_ONLY) ||
3515 (update->flags & REF_ISPRUNING) ||
3516 (update->flags & REF_UPDATE_VIA_HEAD))
3517 return 0;
3518
3519 if (strcmp(update->refname, head_ref))
3520 return 0;
3521
3522 /*
3523 * First make sure that HEAD is not already in the
3524 * transaction. This insertion is O(N) in the transaction
3525 * size, but it happens at most once per transaction.
3526 */
3527 item = string_list_insert(affected_refnames, "HEAD");
3528 if (item->util) {
3529 /* An entry already existed */
3530 strbuf_addf(err,
3531 "multiple updates for 'HEAD' (including one "
3532 "via its referent '%s') are not allowed",
3533 update->refname);
3534 return TRANSACTION_NAME_CONFLICT;
3535 }
3536
3537 new_update = ref_transaction_add_update(
3538 transaction, "HEAD",
3539 update->flags | REF_LOG_ONLY | REF_NODEREF,
3540 update->new_sha1, update->old_sha1,
3541 update->msg);
3542
3543 item->util = new_update;
3544
3545 return 0;
3546}
3547
3548/*
3549 * update is for a symref that points at referent and doesn't have
3550 * REF_NODEREF set. Split it into two updates:
3551 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
3552 * - A new, separate update for the referent reference
3553 * Note that the new update will itself be subject to splitting when
3554 * the iteration gets to it.
3555 */
fcc42ea0
MH
3556static int split_symref_update(struct files_ref_store *refs,
3557 struct ref_update *update,
92b1551b
MH
3558 const char *referent,
3559 struct ref_transaction *transaction,
3560 struct string_list *affected_refnames,
3561 struct strbuf *err)
3562{
3563 struct string_list_item *item;
3564 struct ref_update *new_update;
3565 unsigned int new_flags;
3566
3567 /*
3568 * First make sure that referent is not already in the
3569 * transaction. This insertion is O(N) in the transaction
3570 * size, but it happens at most once per symref in a
3571 * transaction.
3572 */
3573 item = string_list_insert(affected_refnames, referent);
3574 if (item->util) {
3575 /* An entry already existed */
3576 strbuf_addf(err,
3577 "multiple updates for '%s' (including one "
3578 "via symref '%s') are not allowed",
3579 referent, update->refname);
3580 return TRANSACTION_NAME_CONFLICT;
3581 }
3582
3583 new_flags = update->flags;
3584 if (!strcmp(update->refname, "HEAD")) {
3585 /*
3586 * Record that the new update came via HEAD, so that
3587 * when we process it, split_head_update() doesn't try
3588 * to add another reflog update for HEAD. Note that
3589 * this bit will be propagated if the new_update
3590 * itself needs to be split.
3591 */
3592 new_flags |= REF_UPDATE_VIA_HEAD;
3593 }
3594
3595 new_update = ref_transaction_add_update(
3596 transaction, referent, new_flags,
3597 update->new_sha1, update->old_sha1,
3598 update->msg);
3599
6e30b2f6
MH
3600 new_update->parent_update = update;
3601
3602 /*
3603 * Change the symbolic ref update to log only. Also, it
3604 * doesn't need to check its old SHA-1 value, as that will be
3605 * done when new_update is processed.
3606 */
92b1551b 3607 update->flags |= REF_LOG_ONLY | REF_NODEREF;
6e30b2f6 3608 update->flags &= ~REF_HAVE_OLD;
92b1551b
MH
3609
3610 item->util = new_update;
3611
3612 return 0;
3613}
3614
6e30b2f6
MH
3615/*
3616 * Return the refname under which update was originally requested.
3617 */
3618static const char *original_update_refname(struct ref_update *update)
3619{
3620 while (update->parent_update)
3621 update = update->parent_update;
3622
3623 return update->refname;
3624}
3625
e3f51039
MH
3626/*
3627 * Check whether the REF_HAVE_OLD and old_oid values stored in update
3628 * are consistent with oid, which is the reference's current value. If
3629 * everything is OK, return 0; otherwise, write an error message to
3630 * err and return -1.
3631 */
3632static int check_old_oid(struct ref_update *update, struct object_id *oid,
3633 struct strbuf *err)
3634{
3635 if (!(update->flags & REF_HAVE_OLD) ||
3636 !hashcmp(oid->hash, update->old_sha1))
3637 return 0;
3638
3639 if (is_null_sha1(update->old_sha1))
3640 strbuf_addf(err, "cannot lock ref '%s': "
3641 "reference already exists",
3642 original_update_refname(update));
3643 else if (is_null_oid(oid))
3644 strbuf_addf(err, "cannot lock ref '%s': "
3645 "reference is missing but expected %s",
3646 original_update_refname(update),
3647 sha1_to_hex(update->old_sha1));
3648 else
3649 strbuf_addf(err, "cannot lock ref '%s': "
3650 "is at %s but expected %s",
3651 original_update_refname(update),
3652 oid_to_hex(oid),
3653 sha1_to_hex(update->old_sha1));
3654
3655 return -1;
3656}
3657
92b1551b
MH
3658/*
3659 * Prepare for carrying out update:
3660 * - Lock the reference referred to by update.
3661 * - Read the reference under lock.
3662 * - Check that its old SHA-1 value (if specified) is correct, and in
3663 * any case record it in update->lock->old_oid for later use when
3664 * writing the reflog.
3665 * - If it is a symref update without REF_NODEREF, split it up into a
3666 * REF_LOG_ONLY update of the symref and add a separate update for
3667 * the referent to transaction.
3668 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
3669 * update of HEAD.
165056b2 3670 */
b3bbbc5c
MH
3671static int lock_ref_for_update(struct files_ref_store *refs,
3672 struct ref_update *update,
165056b2 3673 struct ref_transaction *transaction,
92b1551b 3674 const char *head_ref,
165056b2
MH
3675 struct string_list *affected_refnames,
3676 struct strbuf *err)
3677{