files-backend: add and use files_packed_refs_path()
[git/git.git] / refs / files-backend.c
CommitLineData
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1#include "../cache.h"
2#include "../refs.h"
3#include "refs-internal.h"
3bc581b9 4#include "../iterator.h"
2880d16f 5#include "../dir-iterator.h"
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6#include "../lockfile.h"
7#include "../object.h"
8#include "../dir.h"
9
10struct ref_lock {
11 char *ref_name;
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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;
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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
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81 /* A pointer to the files_ref_store that contains this ref_dir. */
82 struct files_ref_store *ref_store;
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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,
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165 const char *dirname, size_t len,
166 int incomplete);
167static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
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168static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
169 const unsigned char *new_sha1, const char *msg,
170 int flags, struct strbuf *err);
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171
172static struct ref_dir *get_ref_dir(struct ref_entry *entry)
173{
174 struct ref_dir *dir;
175 assert(entry->flag & REF_DIR);
176 dir = &entry->u.subdir;
177 if (entry->flag & REF_INCOMPLETE) {
178 read_loose_refs(entry->name, dir);
179
180 /*
181 * Manually add refs/bisect, which, being
182 * per-worktree, might not appear in the directory
183 * listing for refs/ in the main repo.
184 */
185 if (!strcmp(entry->name, "refs/")) {
186 int pos = search_ref_dir(dir, "refs/bisect/", 12);
187 if (pos < 0) {
188 struct ref_entry *child_entry;
65a0a8e5 189 child_entry = create_dir_entry(dir->ref_store,
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190 "refs/bisect/",
191 12, 1);
192 add_entry_to_dir(dir, child_entry);
193 read_loose_refs("refs/bisect",
194 &child_entry->u.subdir);
195 }
196 }
197 entry->flag &= ~REF_INCOMPLETE;
198 }
199 return dir;
200}
201
202static struct ref_entry *create_ref_entry(const char *refname,
203 const unsigned char *sha1, int flag,
204 int check_name)
205{
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206 struct ref_entry *ref;
207
208 if (check_name &&
209 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
210 die("Reference has invalid format: '%s'", refname);
96ffc06f 211 FLEX_ALLOC_STR(ref, name, refname);
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212 hashcpy(ref->u.value.oid.hash, sha1);
213 oidclr(&ref->u.value.peeled);
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214 ref->flag = flag;
215 return ref;
216}
217
218static void clear_ref_dir(struct ref_dir *dir);
219
220static void free_ref_entry(struct ref_entry *entry)
221{
222 if (entry->flag & REF_DIR) {
223 /*
224 * Do not use get_ref_dir() here, as that might
225 * trigger the reading of loose refs.
226 */
227 clear_ref_dir(&entry->u.subdir);
228 }
229 free(entry);
230}
231
232/*
233 * Add a ref_entry to the end of dir (unsorted). Entry is always
234 * stored directly in dir; no recursion into subdirectories is
235 * done.
236 */
237static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
238{
239 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
240 dir->entries[dir->nr++] = entry;
241 /* optimize for the case that entries are added in order */
242 if (dir->nr == 1 ||
243 (dir->nr == dir->sorted + 1 &&
244 strcmp(dir->entries[dir->nr - 2]->name,
245 dir->entries[dir->nr - 1]->name) < 0))
246 dir->sorted = dir->nr;
247}
248
249/*
250 * Clear and free all entries in dir, recursively.
251 */
252static void clear_ref_dir(struct ref_dir *dir)
253{
254 int i;
255 for (i = 0; i < dir->nr; i++)
256 free_ref_entry(dir->entries[i]);
257 free(dir->entries);
258 dir->sorted = dir->nr = dir->alloc = 0;
259 dir->entries = NULL;
260}
261
262/*
263 * Create a struct ref_entry object for the specified dirname.
264 * dirname is the name of the directory with a trailing slash (e.g.,
265 * "refs/heads/") or "" for the top-level directory.
266 */
65a0a8e5 267static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
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268 const char *dirname, size_t len,
269 int incomplete)
270{
271 struct ref_entry *direntry;
96ffc06f 272 FLEX_ALLOC_MEM(direntry, name, dirname, len);
65a0a8e5 273 direntry->u.subdir.ref_store = ref_store;
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274 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
275 return direntry;
276}
277
278static int ref_entry_cmp(const void *a, const void *b)
279{
280 struct ref_entry *one = *(struct ref_entry **)a;
281 struct ref_entry *two = *(struct ref_entry **)b;
282 return strcmp(one->name, two->name);
283}
284
285static void sort_ref_dir(struct ref_dir *dir);
286
287struct string_slice {
288 size_t len;
289 const char *str;
290};
291
292static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
293{
294 const struct string_slice *key = key_;
295 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
296 int cmp = strncmp(key->str, ent->name, key->len);
297 if (cmp)
298 return cmp;
299 return '\0' - (unsigned char)ent->name[key->len];
300}
301
302/*
303 * Return the index of the entry with the given refname from the
304 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
305 * no such entry is found. dir must already be complete.
306 */
307static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
308{
309 struct ref_entry **r;
310 struct string_slice key;
311
312 if (refname == NULL || !dir->nr)
313 return -1;
314
315 sort_ref_dir(dir);
316 key.len = len;
317 key.str = refname;
318 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
319 ref_entry_cmp_sslice);
320
321 if (r == NULL)
322 return -1;
323
324 return r - dir->entries;
325}
326
327/*
328 * Search for a directory entry directly within dir (without
329 * recursing). Sort dir if necessary. subdirname must be a directory
330 * name (i.e., end in '/'). If mkdir is set, then create the
331 * directory if it is missing; otherwise, return NULL if the desired
332 * directory cannot be found. dir must already be complete.
333 */
334static struct ref_dir *search_for_subdir(struct ref_dir *dir,
335 const char *subdirname, size_t len,
336 int mkdir)
337{
338 int entry_index = search_ref_dir(dir, subdirname, len);
339 struct ref_entry *entry;
340 if (entry_index == -1) {
341 if (!mkdir)
342 return NULL;
343 /*
344 * Since dir is complete, the absence of a subdir
345 * means that the subdir really doesn't exist;
346 * therefore, create an empty record for it but mark
347 * the record complete.
348 */
65a0a8e5 349 entry = create_dir_entry(dir->ref_store, subdirname, len, 0);
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MH
350 add_entry_to_dir(dir, entry);
351 } else {
352 entry = dir->entries[entry_index];
353 }
354 return get_ref_dir(entry);
355}
356
357/*
358 * If refname is a reference name, find the ref_dir within the dir
359 * tree that should hold refname. If refname is a directory name
360 * (i.e., ends in '/'), then return that ref_dir itself. dir must
361 * represent the top-level directory and must already be complete.
362 * Sort ref_dirs and recurse into subdirectories as necessary. If
363 * mkdir is set, then create any missing directories; otherwise,
364 * return NULL if the desired directory cannot be found.
365 */
366static struct ref_dir *find_containing_dir(struct ref_dir *dir,
367 const char *refname, int mkdir)
368{
369 const char *slash;
370 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
371 size_t dirnamelen = slash - refname + 1;
372 struct ref_dir *subdir;
373 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
374 if (!subdir) {
375 dir = NULL;
376 break;
377 }
378 dir = subdir;
379 }
380
381 return dir;
382}
383
384/*
385 * Find the value entry with the given name in dir, sorting ref_dirs
386 * and recursing into subdirectories as necessary. If the name is not
387 * found or it corresponds to a directory entry, return NULL.
388 */
389static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
390{
391 int entry_index;
392 struct ref_entry *entry;
393 dir = find_containing_dir(dir, refname, 0);
394 if (!dir)
395 return NULL;
396 entry_index = search_ref_dir(dir, refname, strlen(refname));
397 if (entry_index == -1)
398 return NULL;
399 entry = dir->entries[entry_index];
400 return (entry->flag & REF_DIR) ? NULL : entry;
401}
402
403/*
404 * Remove the entry with the given name from dir, recursing into
405 * subdirectories as necessary. If refname is the name of a directory
406 * (i.e., ends with '/'), then remove the directory and its contents.
407 * If the removal was successful, return the number of entries
408 * remaining in the directory entry that contained the deleted entry.
409 * If the name was not found, return -1. Please note that this
410 * function only deletes the entry from the cache; it does not delete
411 * it from the filesystem or ensure that other cache entries (which
412 * might be symbolic references to the removed entry) are updated.
413 * Nor does it remove any containing dir entries that might be made
414 * empty by the removal. dir must represent the top-level directory
415 * and must already be complete.
416 */
417static int remove_entry(struct ref_dir *dir, const char *refname)
418{
419 int refname_len = strlen(refname);
420 int entry_index;
421 struct ref_entry *entry;
422 int is_dir = refname[refname_len - 1] == '/';
423 if (is_dir) {
424 /*
425 * refname represents a reference directory. Remove
426 * the trailing slash; otherwise we will get the
427 * directory *representing* refname rather than the
428 * one *containing* it.
429 */
430 char *dirname = xmemdupz(refname, refname_len - 1);
431 dir = find_containing_dir(dir, dirname, 0);
432 free(dirname);
433 } else {
434 dir = find_containing_dir(dir, refname, 0);
435 }
436 if (!dir)
437 return -1;
438 entry_index = search_ref_dir(dir, refname, refname_len);
439 if (entry_index == -1)
440 return -1;
441 entry = dir->entries[entry_index];
442
443 memmove(&dir->entries[entry_index],
444 &dir->entries[entry_index + 1],
445 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
446 );
447 dir->nr--;
448 if (dir->sorted > entry_index)
449 dir->sorted--;
450 free_ref_entry(entry);
451 return dir->nr;
452}
453
454/*
455 * Add a ref_entry to the ref_dir (unsorted), recursing into
456 * subdirectories as necessary. dir must represent the top-level
457 * directory. Return 0 on success.
458 */
459static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
460{
461 dir = find_containing_dir(dir, ref->name, 1);
462 if (!dir)
463 return -1;
464 add_entry_to_dir(dir, ref);
465 return 0;
466}
467
468/*
469 * Emit a warning and return true iff ref1 and ref2 have the same name
470 * and the same sha1. Die if they have the same name but different
471 * sha1s.
472 */
473static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
474{
475 if (strcmp(ref1->name, ref2->name))
476 return 0;
477
478 /* Duplicate name; make sure that they don't conflict: */
479
480 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
481 /* This is impossible by construction */
482 die("Reference directory conflict: %s", ref1->name);
483
484 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
485 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
486
487 warning("Duplicated ref: %s", ref1->name);
488 return 1;
489}
490
491/*
492 * Sort the entries in dir non-recursively (if they are not already
493 * sorted) and remove any duplicate entries.
494 */
495static void sort_ref_dir(struct ref_dir *dir)
496{
497 int i, j;
498 struct ref_entry *last = NULL;
499
500 /*
501 * This check also prevents passing a zero-length array to qsort(),
502 * which is a problem on some platforms.
503 */
504 if (dir->sorted == dir->nr)
505 return;
506
9ed0d8d6 507 QSORT(dir->entries, dir->nr, ref_entry_cmp);
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MH
508
509 /* Remove any duplicates: */
510 for (i = 0, j = 0; j < dir->nr; j++) {
511 struct ref_entry *entry = dir->entries[j];
512 if (last && is_dup_ref(last, entry))
513 free_ref_entry(entry);
514 else
515 last = dir->entries[i++] = entry;
516 }
517 dir->sorted = dir->nr = i;
518}
519
7bd9bcf3 520/*
a8739244
MH
521 * Return true if refname, which has the specified oid and flags, can
522 * be resolved to an object in the database. If the referred-to object
523 * does not exist, emit a warning and return false.
7bd9bcf3 524 */
a8739244
MH
525static int ref_resolves_to_object(const char *refname,
526 const struct object_id *oid,
527 unsigned int flags)
7bd9bcf3 528{
a8739244 529 if (flags & REF_ISBROKEN)
7bd9bcf3 530 return 0;
a8739244
MH
531 if (!has_sha1_file(oid->hash)) {
532 error("%s does not point to a valid object!", refname);
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MH
533 return 0;
534 }
535 return 1;
536}
537
538/*
a8739244
MH
539 * Return true if the reference described by entry can be resolved to
540 * an object in the database; otherwise, emit a warning and return
541 * false.
7bd9bcf3 542 */
a8739244 543static int entry_resolves_to_object(struct ref_entry *entry)
7bd9bcf3 544{
a8739244
MH
545 return ref_resolves_to_object(entry->name,
546 &entry->u.value.oid, entry->flag);
7bd9bcf3
MH
547}
548
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549typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
550
7bd9bcf3
MH
551/*
552 * Call fn for each reference in dir that has index in the range
553 * offset <= index < dir->nr. Recurse into subdirectories that are in
554 * that index range, sorting them before iterating. This function
555 * does not sort dir itself; it should be sorted beforehand. fn is
556 * called for all references, including broken ones.
557 */
558static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
559 each_ref_entry_fn fn, void *cb_data)
560{
561 int i;
562 assert(dir->sorted == dir->nr);
563 for (i = offset; i < dir->nr; i++) {
564 struct ref_entry *entry = dir->entries[i];
565 int retval;
566 if (entry->flag & REF_DIR) {
567 struct ref_dir *subdir = get_ref_dir(entry);
568 sort_ref_dir(subdir);
569 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
570 } else {
571 retval = fn(entry, cb_data);
572 }
573 if (retval)
574 return retval;
575 }
576 return 0;
577}
578
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MH
579/*
580 * Load all of the refs from the dir into our in-memory cache. The hard work
581 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
582 * through all of the sub-directories. We do not even need to care about
583 * sorting, as traversal order does not matter to us.
584 */
585static void prime_ref_dir(struct ref_dir *dir)
586{
587 int i;
588 for (i = 0; i < dir->nr; i++) {
589 struct ref_entry *entry = dir->entries[i];
590 if (entry->flag & REF_DIR)
591 prime_ref_dir(get_ref_dir(entry));
592 }
593}
594
3bc581b9
MH
595/*
596 * A level in the reference hierarchy that is currently being iterated
597 * through.
598 */
599struct cache_ref_iterator_level {
600 /*
601 * The ref_dir being iterated over at this level. The ref_dir
602 * is sorted before being stored here.
603 */
604 struct ref_dir *dir;
605
606 /*
607 * The index of the current entry within dir (which might
608 * itself be a directory). If index == -1, then the iteration
609 * hasn't yet begun. If index == dir->nr, then the iteration
610 * through this level is over.
611 */
612 int index;
613};
614
615/*
616 * Represent an iteration through a ref_dir in the memory cache. The
617 * iteration recurses through subdirectories.
618 */
619struct cache_ref_iterator {
620 struct ref_iterator base;
621
622 /*
623 * The number of levels currently on the stack. This is always
624 * at least 1, because when it becomes zero the iteration is
625 * ended and this struct is freed.
626 */
627 size_t levels_nr;
628
629 /* The number of levels that have been allocated on the stack */
630 size_t levels_alloc;
631
632 /*
633 * A stack of levels. levels[0] is the uppermost level that is
634 * being iterated over in this iteration. (This is not
635 * necessary the top level in the references hierarchy. If we
636 * are iterating through a subtree, then levels[0] will hold
637 * the ref_dir for that subtree, and subsequent levels will go
638 * on from there.)
639 */
640 struct cache_ref_iterator_level *levels;
641};
642
643static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
644{
645 struct cache_ref_iterator *iter =
646 (struct cache_ref_iterator *)ref_iterator;
647
648 while (1) {
649 struct cache_ref_iterator_level *level =
650 &iter->levels[iter->levels_nr - 1];
651 struct ref_dir *dir = level->dir;
652 struct ref_entry *entry;
653
654 if (level->index == -1)
655 sort_ref_dir(dir);
656
657 if (++level->index == level->dir->nr) {
658 /* This level is exhausted; pop up a level */
659 if (--iter->levels_nr == 0)
660 return ref_iterator_abort(ref_iterator);
661
662 continue;
663 }
664
665 entry = dir->entries[level->index];
666
667 if (entry->flag & REF_DIR) {
668 /* push down a level */
669 ALLOC_GROW(iter->levels, iter->levels_nr + 1,
670 iter->levels_alloc);
671
672 level = &iter->levels[iter->levels_nr++];
673 level->dir = get_ref_dir(entry);
674 level->index = -1;
675 } else {
676 iter->base.refname = entry->name;
677 iter->base.oid = &entry->u.value.oid;
678 iter->base.flags = entry->flag;
679 return ITER_OK;
680 }
681 }
682}
683
684static enum peel_status peel_entry(struct ref_entry *entry, int repeel);
685
686static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
687 struct object_id *peeled)
688{
689 struct cache_ref_iterator *iter =
690 (struct cache_ref_iterator *)ref_iterator;
691 struct cache_ref_iterator_level *level;
692 struct ref_entry *entry;
693
694 level = &iter->levels[iter->levels_nr - 1];
695
696 if (level->index == -1)
697 die("BUG: peel called before advance for cache iterator");
698
699 entry = level->dir->entries[level->index];
700
701 if (peel_entry(entry, 0))
702 return -1;
8694769f 703 oidcpy(peeled, &entry->u.value.peeled);
3bc581b9
MH
704 return 0;
705}
706
707static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator)
708{
709 struct cache_ref_iterator *iter =
710 (struct cache_ref_iterator *)ref_iterator;
711
712 free(iter->levels);
713 base_ref_iterator_free(ref_iterator);
714 return ITER_DONE;
715}
716
717static struct ref_iterator_vtable cache_ref_iterator_vtable = {
718 cache_ref_iterator_advance,
719 cache_ref_iterator_peel,
720 cache_ref_iterator_abort
721};
722
723static struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir)
724{
725 struct cache_ref_iterator *iter;
726 struct ref_iterator *ref_iterator;
727 struct cache_ref_iterator_level *level;
728
729 iter = xcalloc(1, sizeof(*iter));
730 ref_iterator = &iter->base;
731 base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable);
732 ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
733
734 iter->levels_nr = 1;
735 level = &iter->levels[0];
736 level->index = -1;
737 level->dir = dir;
738
739 return ref_iterator;
740}
741
7bd9bcf3
MH
742struct nonmatching_ref_data {
743 const struct string_list *skip;
744 const char *conflicting_refname;
745};
746
747static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
748{
749 struct nonmatching_ref_data *data = vdata;
750
751 if (data->skip && string_list_has_string(data->skip, entry->name))
752 return 0;
753
754 data->conflicting_refname = entry->name;
755 return 1;
756}
757
758/*
759 * Return 0 if a reference named refname could be created without
760 * conflicting with the name of an existing reference in dir.
761 * See verify_refname_available for more information.
762 */
763static int verify_refname_available_dir(const char *refname,
764 const struct string_list *extras,
765 const struct string_list *skip,
766 struct ref_dir *dir,
767 struct strbuf *err)
768{
769 const char *slash;
0845122c 770 const char *extra_refname;
7bd9bcf3
MH
771 int pos;
772 struct strbuf dirname = STRBUF_INIT;
773 int ret = -1;
774
775 /*
776 * For the sake of comments in this function, suppose that
777 * refname is "refs/foo/bar".
778 */
779
780 assert(err);
781
782 strbuf_grow(&dirname, strlen(refname) + 1);
783 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
784 /* Expand dirname to the new prefix, not including the trailing slash: */
785 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
786
787 /*
788 * We are still at a leading dir of the refname (e.g.,
789 * "refs/foo"; if there is a reference with that name,
790 * it is a conflict, *unless* it is in skip.
791 */
792 if (dir) {
793 pos = search_ref_dir(dir, dirname.buf, dirname.len);
794 if (pos >= 0 &&
795 (!skip || !string_list_has_string(skip, dirname.buf))) {
796 /*
797 * We found a reference whose name is
798 * a proper prefix of refname; e.g.,
799 * "refs/foo", and is not in skip.
800 */
801 strbuf_addf(err, "'%s' exists; cannot create '%s'",
802 dirname.buf, refname);
803 goto cleanup;
804 }
805 }
806
807 if (extras && string_list_has_string(extras, dirname.buf) &&
808 (!skip || !string_list_has_string(skip, dirname.buf))) {
809 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
810 refname, dirname.buf);
811 goto cleanup;
812 }
813
814 /*
815 * Otherwise, we can try to continue our search with
816 * the next component. So try to look up the
817 * directory, e.g., "refs/foo/". If we come up empty,
818 * we know there is nothing under this whole prefix,
819 * but even in that case we still have to continue the
820 * search for conflicts with extras.
821 */
822 strbuf_addch(&dirname, '/');
823 if (dir) {
824 pos = search_ref_dir(dir, dirname.buf, dirname.len);
825 if (pos < 0) {
826 /*
827 * There was no directory "refs/foo/",
828 * so there is nothing under this
829 * whole prefix. So there is no need
830 * to continue looking for conflicting
831 * references. But we need to continue
832 * looking for conflicting extras.
833 */
834 dir = NULL;
835 } else {
836 dir = get_ref_dir(dir->entries[pos]);
837 }
838 }
839 }
840
841 /*
842 * We are at the leaf of our refname (e.g., "refs/foo/bar").
843 * There is no point in searching for a reference with that
844 * name, because a refname isn't considered to conflict with
845 * itself. But we still need to check for references whose
846 * names are in the "refs/foo/bar/" namespace, because they
847 * *do* conflict.
848 */
849 strbuf_addstr(&dirname, refname + dirname.len);
850 strbuf_addch(&dirname, '/');
851
852 if (dir) {
853 pos = search_ref_dir(dir, dirname.buf, dirname.len);
854
855 if (pos >= 0) {
856 /*
857 * We found a directory named "$refname/"
858 * (e.g., "refs/foo/bar/"). It is a problem
859 * iff it contains any ref that is not in
860 * "skip".
861 */
862 struct nonmatching_ref_data data;
863
864 data.skip = skip;
865 data.conflicting_refname = NULL;
866 dir = get_ref_dir(dir->entries[pos]);
867 sort_ref_dir(dir);
868 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
869 strbuf_addf(err, "'%s' exists; cannot create '%s'",
870 data.conflicting_refname, refname);
871 goto cleanup;
872 }
873 }
874 }
875
0845122c
DT
876 extra_refname = find_descendant_ref(dirname.buf, extras, skip);
877 if (extra_refname)
878 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
879 refname, extra_refname);
880 else
881 ret = 0;
7bd9bcf3
MH
882
883cleanup:
884 strbuf_release(&dirname);
885 return ret;
886}
887
888struct packed_ref_cache {
889 struct ref_entry *root;
890
891 /*
892 * Count of references to the data structure in this instance,
65a0a8e5
MH
893 * including the pointer from files_ref_store::packed if any.
894 * The data will not be freed as long as the reference count
895 * is nonzero.
7bd9bcf3
MH
896 */
897 unsigned int referrers;
898
899 /*
900 * Iff the packed-refs file associated with this instance is
901 * currently locked for writing, this points at the associated
902 * lock (which is owned by somebody else). The referrer count
903 * is also incremented when the file is locked and decremented
904 * when it is unlocked.
905 */
906 struct lock_file *lock;
907
908 /* The metadata from when this packed-refs cache was read */
909 struct stat_validity validity;
910};
911
912/*
913 * Future: need to be in "struct repository"
914 * when doing a full libification.
915 */
00eebe35
MH
916struct files_ref_store {
917 struct ref_store base;
32c597e7
MH
918
919 /*
920 * The name of the submodule represented by this object, or
9c7d772b
MH
921 * NULL if it represents the main repository's reference
922 * store:
32c597e7
MH
923 */
924 const char *submodule;
925
33dfb9f3
NTND
926 char *packed_refs_path;
927
7bd9bcf3
MH
928 struct ref_entry *loose;
929 struct packed_ref_cache *packed;
00eebe35 930};
7bd9bcf3
MH
931
932/* Lock used for the main packed-refs file: */
933static struct lock_file packlock;
934
935/*
936 * Increment the reference count of *packed_refs.
937 */
938static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
939{
940 packed_refs->referrers++;
941}
942
943/*
944 * Decrease the reference count of *packed_refs. If it goes to zero,
945 * free *packed_refs and return true; otherwise return false.
946 */
947static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
948{
949 if (!--packed_refs->referrers) {
950 free_ref_entry(packed_refs->root);
951 stat_validity_clear(&packed_refs->validity);
952 free(packed_refs);
953 return 1;
954 } else {
955 return 0;
956 }
957}
958
65a0a8e5 959static void clear_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
960{
961 if (refs->packed) {
962 struct packed_ref_cache *packed_refs = refs->packed;
963
964 if (packed_refs->lock)
965 die("internal error: packed-ref cache cleared while locked");
966 refs->packed = NULL;
967 release_packed_ref_cache(packed_refs);
968 }
969}
970
65a0a8e5 971static void clear_loose_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
972{
973 if (refs->loose) {
974 free_ref_entry(refs->loose);
975 refs->loose = NULL;
976 }
977}
978
a2d5156c
JK
979/*
980 * Create a new submodule ref cache and add it to the internal
981 * set of caches.
982 */
00eebe35 983static struct ref_store *files_ref_store_create(const char *submodule)
7bd9bcf3 984{
00eebe35
MH
985 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
986 struct ref_store *ref_store = (struct ref_store *)refs;
7bd9bcf3 987
fbfd0a29 988 base_ref_store_init(ref_store, &refs_be_files);
7bd9bcf3 989
33dfb9f3
NTND
990 if (submodule) {
991 refs->submodule = xstrdup(submodule);
992 refs->packed_refs_path = git_pathdup_submodule(
993 refs->submodule, "packed-refs");
994 return ref_store;
995 }
996
997 refs->packed_refs_path = git_pathdup("packed-refs");
7bd9bcf3 998
00eebe35 999 return ref_store;
a2d5156c 1000}
7bd9bcf3 1001
32c597e7
MH
1002/*
1003 * Die if refs is for a submodule (i.e., not for the main repository).
1004 * caller is used in any necessary error messages.
1005 */
1006static void files_assert_main_repository(struct files_ref_store *refs,
1007 const char *caller)
1008{
9c7d772b 1009 if (refs->submodule)
32c597e7
MH
1010 die("BUG: %s called for a submodule", caller);
1011}
1012
a2d5156c 1013/*
00eebe35
MH
1014 * Downcast ref_store to files_ref_store. Die if ref_store is not a
1015 * files_ref_store. If submodule_allowed is not true, then also die if
1016 * files_ref_store is for a submodule (i.e., not for the main
1017 * repository). caller is used in any necessary error messages.
a2d5156c 1018 */
00eebe35
MH
1019static struct files_ref_store *files_downcast(
1020 struct ref_store *ref_store, int submodule_allowed,
1021 const char *caller)
a2d5156c 1022{
32c597e7
MH
1023 struct files_ref_store *refs;
1024
00eebe35
MH
1025 if (ref_store->be != &refs_be_files)
1026 die("BUG: ref_store is type \"%s\" not \"files\" in %s",
1027 ref_store->be->name, caller);
2eed2780 1028
32c597e7
MH
1029 refs = (struct files_ref_store *)ref_store;
1030
00eebe35 1031 if (!submodule_allowed)
32c597e7 1032 files_assert_main_repository(refs, caller);
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
7bd9bcf3 1170/*
65a0a8e5
MH
1171 * Get the packed_ref_cache for the specified files_ref_store,
1172 * creating it if necessary.
7bd9bcf3 1173 */
65a0a8e5 1174static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3 1175{
33dfb9f3 1176 const char *packed_refs_file = files_packed_refs_path(refs);
7bd9bcf3
MH
1177
1178 if (refs->packed &&
1179 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1180 clear_packed_ref_cache(refs);
1181
1182 if (!refs->packed) {
1183 FILE *f;
1184
1185 refs->packed = xcalloc(1, sizeof(*refs->packed));
1186 acquire_packed_ref_cache(refs->packed);
1187 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1188 f = fopen(packed_refs_file, "r");
1189 if (f) {
1190 stat_validity_update(&refs->packed->validity, fileno(f));
1191 read_packed_refs(f, get_ref_dir(refs->packed->root));
1192 fclose(f);
1193 }
1194 }
7bd9bcf3
MH
1195 return refs->packed;
1196}
1197
1198static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1199{
1200 return get_ref_dir(packed_ref_cache->root);
1201}
1202
65a0a8e5 1203static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1204{
1205 return get_packed_ref_dir(get_packed_ref_cache(refs));
1206}
1207
1208/*
1209 * Add a reference to the in-memory packed reference cache. This may
1210 * only be called while the packed-refs file is locked (see
1211 * lock_packed_refs()). To actually write the packed-refs file, call
1212 * commit_packed_refs().
1213 */
d99825ab
MH
1214static void add_packed_ref(struct files_ref_store *refs,
1215 const char *refname, const unsigned char *sha1)
7bd9bcf3 1216{
00eebe35 1217 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
1218
1219 if (!packed_ref_cache->lock)
1220 die("internal error: packed refs not locked");
1221 add_ref(get_packed_ref_dir(packed_ref_cache),
1222 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1223}
1224
1225/*
1226 * Read the loose references from the namespace dirname into dir
1227 * (without recursing). dirname must end with '/'. dir must be the
1228 * directory entry corresponding to dirname.
1229 */
1230static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1231{
65a0a8e5 1232 struct files_ref_store *refs = dir->ref_store;
7bd9bcf3
MH
1233 DIR *d;
1234 struct dirent *de;
1235 int dirnamelen = strlen(dirname);
1236 struct strbuf refname;
1237 struct strbuf path = STRBUF_INIT;
1238 size_t path_baselen;
99b43a61 1239 int err = 0;
7bd9bcf3 1240
9c7d772b 1241 if (refs->submodule)
32c597e7 1242 err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);
7bd9bcf3
MH
1243 else
1244 strbuf_git_path(&path, "%s", dirname);
1245 path_baselen = path.len;
1246
99b43a61
JK
1247 if (err) {
1248 strbuf_release(&path);
1249 return;
1250 }
1251
7bd9bcf3
MH
1252 d = opendir(path.buf);
1253 if (!d) {
1254 strbuf_release(&path);
1255 return;
1256 }
1257
1258 strbuf_init(&refname, dirnamelen + 257);
1259 strbuf_add(&refname, dirname, dirnamelen);
1260
1261 while ((de = readdir(d)) != NULL) {
1262 unsigned char sha1[20];
1263 struct stat st;
1264 int flag;
1265
1266 if (de->d_name[0] == '.')
1267 continue;
1268 if (ends_with(de->d_name, ".lock"))
1269 continue;
1270 strbuf_addstr(&refname, de->d_name);
1271 strbuf_addstr(&path, de->d_name);
1272 if (stat(path.buf, &st) < 0) {
1273 ; /* silently ignore */
1274 } else if (S_ISDIR(st.st_mode)) {
1275 strbuf_addch(&refname, '/');
1276 add_entry_to_dir(dir,
1277 create_dir_entry(refs, refname.buf,
1278 refname.len, 1));
1279 } else {
3c0cb0cb
MH
1280 if (!resolve_ref_recursively(&refs->base,
1281 refname.buf,
1282 RESOLVE_REF_READING,
1283 sha1, &flag)) {
7bd9bcf3
MH
1284 hashclr(sha1);
1285 flag |= REF_ISBROKEN;
1286 } else if (is_null_sha1(sha1)) {
1287 /*
1288 * It is so astronomically unlikely
1289 * that NULL_SHA1 is the SHA-1 of an
1290 * actual object that we consider its
1291 * appearance in a loose reference
1292 * file to be repo corruption
1293 * (probably due to a software bug).
1294 */
1295 flag |= REF_ISBROKEN;
1296 }
1297
1298 if (check_refname_format(refname.buf,
1299 REFNAME_ALLOW_ONELEVEL)) {
1300 if (!refname_is_safe(refname.buf))
1301 die("loose refname is dangerous: %s", refname.buf);
1302 hashclr(sha1);
1303 flag |= REF_BAD_NAME | REF_ISBROKEN;
1304 }
1305 add_entry_to_dir(dir,
1306 create_ref_entry(refname.buf, sha1, flag, 0));
1307 }
1308 strbuf_setlen(&refname, dirnamelen);
1309 strbuf_setlen(&path, path_baselen);
1310 }
1311 strbuf_release(&refname);
1312 strbuf_release(&path);
1313 closedir(d);
1314}
1315
65a0a8e5 1316static struct ref_dir *get_loose_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1317{
1318 if (!refs->loose) {
1319 /*
1320 * Mark the top-level directory complete because we
1321 * are about to read the only subdirectory that can
1322 * hold references:
1323 */
1324 refs->loose = create_dir_entry(refs, "", 0, 0);
1325 /*
1326 * Create an incomplete entry for "refs/":
1327 */
1328 add_entry_to_dir(get_ref_dir(refs->loose),
1329 create_dir_entry(refs, "refs/", 5, 1));
1330 }
1331 return get_ref_dir(refs->loose);
1332}
1333
7bd9bcf3
MH
1334/*
1335 * Return the ref_entry for the given refname from the packed
1336 * references. If it does not exist, return NULL.
1337 */
f0d21efc
MH
1338static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
1339 const char *refname)
7bd9bcf3 1340{
00eebe35 1341 return find_ref(get_packed_refs(refs), refname);
7bd9bcf3
MH
1342}
1343
1344/*
419c6f4c 1345 * A loose ref file doesn't exist; check for a packed ref.
7bd9bcf3 1346 */
611118d0
MH
1347static int resolve_packed_ref(struct files_ref_store *refs,
1348 const char *refname,
1349 unsigned char *sha1, unsigned int *flags)
7bd9bcf3
MH
1350{
1351 struct ref_entry *entry;
1352
1353 /*
1354 * The loose reference file does not exist; check for a packed
1355 * reference.
1356 */
f0d21efc 1357 entry = get_packed_ref(refs, refname);
7bd9bcf3
MH
1358 if (entry) {
1359 hashcpy(sha1, entry->u.value.oid.hash);
a70a93b7 1360 *flags |= REF_ISPACKED;
7bd9bcf3
MH
1361 return 0;
1362 }
419c6f4c
MH
1363 /* refname is not a packed reference. */
1364 return -1;
7bd9bcf3
MH
1365}
1366
e1e33b72
MH
1367static int files_read_raw_ref(struct ref_store *ref_store,
1368 const char *refname, unsigned char *sha1,
1369 struct strbuf *referent, unsigned int *type)
7bd9bcf3 1370{
4308651c 1371 struct files_ref_store *refs =
34c7ad8f 1372 files_downcast(ref_store, 1, "read_raw_ref");
42a38cf7
MH
1373 struct strbuf sb_contents = STRBUF_INIT;
1374 struct strbuf sb_path = STRBUF_INIT;
7048653a
DT
1375 const char *path;
1376 const char *buf;
1377 struct stat st;
1378 int fd;
42a38cf7
MH
1379 int ret = -1;
1380 int save_errno;
e8c42cb9 1381 int remaining_retries = 3;
7bd9bcf3 1382
fa96ea1b 1383 *type = 0;
42a38cf7 1384 strbuf_reset(&sb_path);
34c7ad8f 1385
9c7d772b 1386 if (refs->submodule)
32c597e7 1387 strbuf_git_path_submodule(&sb_path, refs->submodule, "%s", refname);
34c7ad8f
MH
1388 else
1389 strbuf_git_path(&sb_path, "%s", refname);
1390
42a38cf7 1391 path = sb_path.buf;
7bd9bcf3 1392
7048653a
DT
1393stat_ref:
1394 /*
1395 * We might have to loop back here to avoid a race
1396 * condition: first we lstat() the file, then we try
1397 * to read it as a link or as a file. But if somebody
1398 * changes the type of the file (file <-> directory
1399 * <-> symlink) between the lstat() and reading, then
1400 * we don't want to report that as an error but rather
1401 * try again starting with the lstat().
e8c42cb9
JK
1402 *
1403 * We'll keep a count of the retries, though, just to avoid
1404 * any confusing situation sending us into an infinite loop.
7048653a 1405 */
7bd9bcf3 1406
e8c42cb9
JK
1407 if (remaining_retries-- <= 0)
1408 goto out;
1409
7048653a
DT
1410 if (lstat(path, &st) < 0) {
1411 if (errno != ENOENT)
42a38cf7 1412 goto out;
611118d0 1413 if (resolve_packed_ref(refs, refname, sha1, type)) {
7048653a 1414 errno = ENOENT;
42a38cf7 1415 goto out;
7bd9bcf3 1416 }
42a38cf7
MH
1417 ret = 0;
1418 goto out;
7bd9bcf3 1419 }
7bd9bcf3 1420
7048653a
DT
1421 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1422 if (S_ISLNK(st.st_mode)) {
42a38cf7
MH
1423 strbuf_reset(&sb_contents);
1424 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
7048653a 1425 if (errno == ENOENT || errno == EINVAL)
7bd9bcf3
MH
1426 /* inconsistent with lstat; retry */
1427 goto stat_ref;
1428 else
42a38cf7 1429 goto out;
7bd9bcf3 1430 }
42a38cf7
MH
1431 if (starts_with(sb_contents.buf, "refs/") &&
1432 !check_refname_format(sb_contents.buf, 0)) {
92b38093 1433 strbuf_swap(&sb_contents, referent);
3a0b6b9a 1434 *type |= REF_ISSYMREF;
42a38cf7
MH
1435 ret = 0;
1436 goto out;
7bd9bcf3 1437 }
3f7bd767
JK
1438 /*
1439 * It doesn't look like a refname; fall through to just
1440 * treating it like a non-symlink, and reading whatever it
1441 * points to.
1442 */
7048653a 1443 }
7bd9bcf3 1444
7048653a
DT
1445 /* Is it a directory? */
1446 if (S_ISDIR(st.st_mode)) {
e167a567
MH
1447 /*
1448 * Even though there is a directory where the loose
1449 * ref is supposed to be, there could still be a
1450 * packed ref:
1451 */
611118d0 1452 if (resolve_packed_ref(refs, refname, sha1, type)) {
e167a567
MH
1453 errno = EISDIR;
1454 goto out;
1455 }
1456 ret = 0;
42a38cf7 1457 goto out;
7048653a
DT
1458 }
1459
1460 /*
1461 * Anything else, just open it and try to use it as
1462 * a ref
1463 */
1464 fd = open(path, O_RDONLY);
1465 if (fd < 0) {
3f7bd767 1466 if (errno == ENOENT && !S_ISLNK(st.st_mode))
7048653a
DT
1467 /* inconsistent with lstat; retry */
1468 goto stat_ref;
1469 else
42a38cf7 1470 goto out;
7048653a 1471 }
42a38cf7
MH
1472 strbuf_reset(&sb_contents);
1473 if (strbuf_read(&sb_contents, fd, 256) < 0) {
7048653a
DT
1474 int save_errno = errno;
1475 close(fd);
1476 errno = save_errno;
42a38cf7 1477 goto out;
7048653a
DT
1478 }
1479 close(fd);
42a38cf7
MH
1480 strbuf_rtrim(&sb_contents);
1481 buf = sb_contents.buf;
7048653a
DT
1482 if (starts_with(buf, "ref:")) {
1483 buf += 4;
7bd9bcf3
MH
1484 while (isspace(*buf))
1485 buf++;
7048653a 1486
92b38093
MH
1487 strbuf_reset(referent);
1488 strbuf_addstr(referent, buf);
3a0b6b9a 1489 *type |= REF_ISSYMREF;
42a38cf7
MH
1490 ret = 0;
1491 goto out;
7bd9bcf3 1492 }
7bd9bcf3 1493
7048653a
DT
1494 /*
1495 * Please note that FETCH_HEAD has additional
1496 * data after the sha.
1497 */
1498 if (get_sha1_hex(buf, sha1) ||
1499 (buf[40] != '\0' && !isspace(buf[40]))) {
3a0b6b9a 1500 *type |= REF_ISBROKEN;
7048653a 1501 errno = EINVAL;
42a38cf7 1502 goto out;
7048653a
DT
1503 }
1504
42a38cf7 1505 ret = 0;
7bd9bcf3 1506
42a38cf7
MH
1507out:
1508 save_errno = errno;
7bd9bcf3
MH
1509 strbuf_release(&sb_path);
1510 strbuf_release(&sb_contents);
42a38cf7 1511 errno = save_errno;
7bd9bcf3
MH
1512 return ret;
1513}
1514
8415d247
MH
1515static void unlock_ref(struct ref_lock *lock)
1516{
1517 /* Do not free lock->lk -- atexit() still looks at them */
1518 if (lock->lk)
1519 rollback_lock_file(lock->lk);
1520 free(lock->ref_name);
8415d247
MH
1521 free(lock);
1522}
1523
92b1551b
MH
1524/*
1525 * Lock refname, without following symrefs, and set *lock_p to point
1526 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
1527 * and type similarly to read_raw_ref().
1528 *
1529 * The caller must verify that refname is a "safe" reference name (in
1530 * the sense of refname_is_safe()) before calling this function.
1531 *
1532 * If the reference doesn't already exist, verify that refname doesn't
1533 * have a D/F conflict with any existing references. extras and skip
1534 * are passed to verify_refname_available_dir() for this check.
1535 *
1536 * If mustexist is not set and the reference is not found or is
1537 * broken, lock the reference anyway but clear sha1.
1538 *
1539 * Return 0 on success. On failure, write an error message to err and
1540 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
1541 *
1542 * Implementation note: This function is basically
1543 *
1544 * lock reference
1545 * read_raw_ref()
1546 *
1547 * but it includes a lot more code to
1548 * - Deal with possible races with other processes
1549 * - Avoid calling verify_refname_available_dir() when it can be
1550 * avoided, namely if we were successfully able to read the ref
1551 * - Generate informative error messages in the case of failure
1552 */
f7b0a987
MH
1553static int lock_raw_ref(struct files_ref_store *refs,
1554 const char *refname, int mustexist,
92b1551b
MH
1555 const struct string_list *extras,
1556 const struct string_list *skip,
1557 struct ref_lock **lock_p,
1558 struct strbuf *referent,
1559 unsigned int *type,
1560 struct strbuf *err)
1561{
1562 struct ref_lock *lock;
1563 struct strbuf ref_file = STRBUF_INIT;
1564 int attempts_remaining = 3;
1565 int ret = TRANSACTION_GENERIC_ERROR;
1566
1567 assert(err);
32c597e7 1568 files_assert_main_repository(refs, "lock_raw_ref");
f7b0a987 1569
92b1551b
MH
1570 *type = 0;
1571
1572 /* First lock the file so it can't change out from under us. */
1573
1574 *lock_p = lock = xcalloc(1, sizeof(*lock));
1575
1576 lock->ref_name = xstrdup(refname);
92b1551b
MH
1577 strbuf_git_path(&ref_file, "%s", refname);
1578
1579retry:
1580 switch (safe_create_leading_directories(ref_file.buf)) {
1581 case SCLD_OK:
1582 break; /* success */
1583 case SCLD_EXISTS:
1584 /*
1585 * Suppose refname is "refs/foo/bar". We just failed
1586 * to create the containing directory, "refs/foo",
1587 * because there was a non-directory in the way. This
1588 * indicates a D/F conflict, probably because of
1589 * another reference such as "refs/foo". There is no
1590 * reason to expect this error to be transitory.
1591 */
1592 if (verify_refname_available(refname, extras, skip, err)) {
1593 if (mustexist) {
1594 /*
1595 * To the user the relevant error is
1596 * that the "mustexist" reference is
1597 * missing:
1598 */
1599 strbuf_reset(err);
1600 strbuf_addf(err, "unable to resolve reference '%s'",
1601 refname);
1602 } else {
1603 /*
1604 * The error message set by
1605 * verify_refname_available_dir() is OK.
1606 */
1607 ret = TRANSACTION_NAME_CONFLICT;
1608 }
1609 } else {
1610 /*
1611 * The file that is in the way isn't a loose
1612 * reference. Report it as a low-level
1613 * failure.
1614 */
1615 strbuf_addf(err, "unable to create lock file %s.lock; "
1616 "non-directory in the way",
1617 ref_file.buf);
1618 }
1619 goto error_return;
1620 case SCLD_VANISHED:
1621 /* Maybe another process was tidying up. Try again. */
1622 if (--attempts_remaining > 0)
1623 goto retry;
1624 /* fall through */
1625 default:
1626 strbuf_addf(err, "unable to create directory for %s",
1627 ref_file.buf);
1628 goto error_return;
1629 }
1630
1631 if (!lock->lk)
1632 lock->lk = xcalloc(1, sizeof(struct lock_file));
1633
1634 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
1635 if (errno == ENOENT && --attempts_remaining > 0) {
1636 /*
1637 * Maybe somebody just deleted one of the
1638 * directories leading to ref_file. Try
1639 * again:
1640 */
1641 goto retry;
1642 } else {
1643 unable_to_lock_message(ref_file.buf, errno, err);
1644 goto error_return;
1645 }
1646 }
1647
1648 /*
1649 * Now we hold the lock and can read the reference without
1650 * fear that its value will change.
1651 */
1652
f7b0a987 1653 if (files_read_raw_ref(&refs->base, refname,
e1e33b72 1654 lock->old_oid.hash, referent, type)) {
92b1551b
MH
1655 if (errno == ENOENT) {
1656 if (mustexist) {
1657 /* Garden variety missing reference. */
1658 strbuf_addf(err, "unable to resolve reference '%s'",
1659 refname);
1660 goto error_return;
1661 } else {
1662 /*
1663 * Reference is missing, but that's OK. We
1664 * know that there is not a conflict with
1665 * another loose reference because
1666 * (supposing that we are trying to lock
1667 * reference "refs/foo/bar"):
1668 *
1669 * - We were successfully able to create
1670 * the lockfile refs/foo/bar.lock, so we
1671 * know there cannot be a loose reference
1672 * named "refs/foo".
1673 *
1674 * - We got ENOENT and not EISDIR, so we
1675 * know that there cannot be a loose
1676 * reference named "refs/foo/bar/baz".
1677 */
1678 }
1679 } else if (errno == EISDIR) {
1680 /*
1681 * There is a directory in the way. It might have
1682 * contained references that have been deleted. If
1683 * we don't require that the reference already
1684 * exists, try to remove the directory so that it
1685 * doesn't cause trouble when we want to rename the
1686 * lockfile into place later.
1687 */
1688 if (mustexist) {
1689 /* Garden variety missing reference. */
1690 strbuf_addf(err, "unable to resolve reference '%s'",
1691 refname);
1692 goto error_return;
1693 } else if (remove_dir_recursively(&ref_file,
1694 REMOVE_DIR_EMPTY_ONLY)) {
1695 if (verify_refname_available_dir(
1696 refname, extras, skip,
00eebe35 1697 get_loose_refs(refs),
92b1551b
MH
1698 err)) {
1699 /*
1700 * The error message set by
1701 * verify_refname_available() is OK.
1702 */
1703 ret = TRANSACTION_NAME_CONFLICT;
1704 goto error_return;
1705 } else {
1706 /*
1707 * We can't delete the directory,
1708 * but we also don't know of any
1709 * references that it should
1710 * contain.
1711 */
1712 strbuf_addf(err, "there is a non-empty directory '%s' "
1713 "blocking reference '%s'",
1714 ref_file.buf, refname);
1715 goto error_return;
1716 }
1717 }
1718 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
1719 strbuf_addf(err, "unable to resolve reference '%s': "
1720 "reference broken", refname);
1721 goto error_return;
1722 } else {
1723 strbuf_addf(err, "unable to resolve reference '%s': %s",
1724 refname, strerror(errno));
1725 goto error_return;
1726 }
1727
1728 /*
1729 * If the ref did not exist and we are creating it,
1730 * make sure there is no existing packed ref whose
1731 * name begins with our refname, nor a packed ref
1732 * whose name is a proper prefix of our refname.
1733 */
1734 if (verify_refname_available_dir(
1735 refname, extras, skip,
00eebe35 1736 get_packed_refs(refs),
92b1551b
MH
1737 err)) {
1738 goto error_return;
1739 }
1740 }
1741
1742 ret = 0;
1743 goto out;
1744
1745error_return:
1746 unlock_ref(lock);
1747 *lock_p = NULL;
1748
1749out:
1750 strbuf_release(&ref_file);
1751 return ret;
1752}
1753
7bd9bcf3
MH
1754/*
1755 * Peel the entry (if possible) and return its new peel_status. If
1756 * repeel is true, re-peel the entry even if there is an old peeled
1757 * value that is already stored in it.
1758 *
1759 * It is OK to call this function with a packed reference entry that
1760 * might be stale and might even refer to an object that has since
1761 * been garbage-collected. In such a case, if the entry has
1762 * REF_KNOWS_PEELED then leave the status unchanged and return
1763 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1764 */
1765static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1766{
1767 enum peel_status status;
1768
1769 if (entry->flag & REF_KNOWS_PEELED) {
1770 if (repeel) {
1771 entry->flag &= ~REF_KNOWS_PEELED;
1772 oidclr(&entry->u.value.peeled);
1773 } else {
1774 return is_null_oid(&entry->u.value.peeled) ?
1775 PEEL_NON_TAG : PEEL_PEELED;
1776 }
1777 }
1778 if (entry->flag & REF_ISBROKEN)
1779 return PEEL_BROKEN;
1780 if (entry->flag & REF_ISSYMREF)
1781 return PEEL_IS_SYMREF;
1782
1783 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1784 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1785 entry->flag |= REF_KNOWS_PEELED;
1786 return status;
1787}
1788
bd427cf2
MH
1789static int files_peel_ref(struct ref_store *ref_store,
1790 const char *refname, unsigned char *sha1)
7bd9bcf3 1791{
bd427cf2 1792 struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
7bd9bcf3
MH
1793 int flag;
1794 unsigned char base[20];
1795
4c4de895
MH
1796 if (current_ref_iter && current_ref_iter->refname == refname) {
1797 struct object_id peeled;
1798
1799 if (ref_iterator_peel(current_ref_iter, &peeled))
7bd9bcf3 1800 return -1;
4c4de895 1801 hashcpy(sha1, peeled.hash);
7bd9bcf3
MH
1802 return 0;
1803 }
1804
1805 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1806 return -1;
1807
1808 /*
1809 * If the reference is packed, read its ref_entry from the
1810 * cache in the hope that we already know its peeled value.
1811 * We only try this optimization on packed references because
1812 * (a) forcing the filling of the loose reference cache could
1813 * be expensive and (b) loose references anyway usually do not
1814 * have REF_KNOWS_PEELED.
1815 */
1816 if (flag & REF_ISPACKED) {
f0d21efc 1817 struct ref_entry *r = get_packed_ref(refs, refname);
7bd9bcf3
MH
1818 if (r) {
1819 if (peel_entry(r, 0))
1820 return -1;
1821 hashcpy(sha1, r->u.value.peeled.hash);
1822 return 0;
1823 }
1824 }
1825
1826 return peel_object(base, sha1);
1827}
1828
3bc581b9
MH
1829struct files_ref_iterator {
1830 struct ref_iterator base;
1831
7bd9bcf3 1832 struct packed_ref_cache *packed_ref_cache;
3bc581b9
MH
1833 struct ref_iterator *iter0;
1834 unsigned int flags;
1835};
7bd9bcf3 1836
3bc581b9
MH
1837static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
1838{
1839 struct files_ref_iterator *iter =
1840 (struct files_ref_iterator *)ref_iterator;
1841 int ok;
7bd9bcf3 1842
3bc581b9 1843 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
0c09ec07
DT
1844 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
1845 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
1846 continue;
1847
3bc581b9
MH
1848 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
1849 !ref_resolves_to_object(iter->iter0->refname,
1850 iter->iter0->oid,
1851 iter->iter0->flags))
1852 continue;
1853
1854 iter->base.refname = iter->iter0->refname;
1855 iter->base.oid = iter->iter0->oid;
1856 iter->base.flags = iter->iter0->flags;
1857 return ITER_OK;
7bd9bcf3
MH
1858 }
1859
3bc581b9
MH
1860 iter->iter0 = NULL;
1861 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
1862 ok = ITER_ERROR;
1863
1864 return ok;
7bd9bcf3
MH
1865}
1866
3bc581b9
MH
1867static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
1868 struct object_id *peeled)
7bd9bcf3 1869{
3bc581b9
MH
1870 struct files_ref_iterator *iter =
1871 (struct files_ref_iterator *)ref_iterator;
93770590 1872
3bc581b9
MH
1873 return ref_iterator_peel(iter->iter0, peeled);
1874}
1875
1876static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
1877{
1878 struct files_ref_iterator *iter =
1879 (struct files_ref_iterator *)ref_iterator;
1880 int ok = ITER_DONE;
1881
1882 if (iter->iter0)
1883 ok = ref_iterator_abort(iter->iter0);
1884
1885 release_packed_ref_cache(iter->packed_ref_cache);
1886 base_ref_iterator_free(ref_iterator);
1887 return ok;
1888}
1889
1890static struct ref_iterator_vtable files_ref_iterator_vtable = {
1891 files_ref_iterator_advance,
1892 files_ref_iterator_peel,
1893 files_ref_iterator_abort
1894};
1895
1a769003 1896static struct ref_iterator *files_ref_iterator_begin(
37b6f6d5 1897 struct ref_store *ref_store,
3bc581b9
MH
1898 const char *prefix, unsigned int flags)
1899{
00eebe35 1900 struct files_ref_store *refs =
37b6f6d5 1901 files_downcast(ref_store, 1, "ref_iterator_begin");
3bc581b9
MH
1902 struct ref_dir *loose_dir, *packed_dir;
1903 struct ref_iterator *loose_iter, *packed_iter;
1904 struct files_ref_iterator *iter;
1905 struct ref_iterator *ref_iterator;
1906
7bd9bcf3
MH
1907 if (ref_paranoia < 0)
1908 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1909 if (ref_paranoia)
3bc581b9
MH
1910 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1911
1912 iter = xcalloc(1, sizeof(*iter));
1913 ref_iterator = &iter->base;
1914 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
1915
1916 /*
1917 * We must make sure that all loose refs are read before
1918 * accessing the packed-refs file; this avoids a race
1919 * condition if loose refs are migrated to the packed-refs
1920 * file by a simultaneous process, but our in-memory view is
1921 * from before the migration. We ensure this as follows:
1922 * First, we call prime_ref_dir(), which pre-reads the loose
1923 * references for the subtree into the cache. (If they've
1924 * already been read, that's OK; we only need to guarantee
1925 * that they're read before the packed refs, not *how much*
1926 * before.) After that, we call get_packed_ref_cache(), which
1927 * internally checks whether the packed-ref cache is up to
1928 * date with what is on disk, and re-reads it if not.
1929 */
1930
1931 loose_dir = get_loose_refs(refs);
1932
1933 if (prefix && *prefix)
1934 loose_dir = find_containing_dir(loose_dir, prefix, 0);
7bd9bcf3 1935
3bc581b9
MH
1936 if (loose_dir) {
1937 prime_ref_dir(loose_dir);
1938 loose_iter = cache_ref_iterator_begin(loose_dir);
1939 } else {
1940 /* There's nothing to iterate over. */
1941 loose_iter = empty_ref_iterator_begin();
1942 }
1943
1944 iter->packed_ref_cache = get_packed_ref_cache(refs);
1945 acquire_packed_ref_cache(iter->packed_ref_cache);
1946 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);
1947
1948 if (prefix && *prefix)
1949 packed_dir = find_containing_dir(packed_dir, prefix, 0);
1950
1951 if (packed_dir) {
1952 packed_iter = cache_ref_iterator_begin(packed_dir);
1953 } else {
1954 /* There's nothing to iterate over. */
1955 packed_iter = empty_ref_iterator_begin();
1956 }
1957
1958 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
1959 iter->flags = flags;
1960
1961 return ref_iterator;
7bd9bcf3
MH
1962}
1963
7bd9bcf3
MH
1964/*
1965 * Verify that the reference locked by lock has the value old_sha1.
1966 * Fail if the reference doesn't exist and mustexist is set. Return 0
1967 * on success. On error, write an error message to err, set errno, and
1968 * return a negative value.
1969 */
1970static int verify_lock(struct ref_lock *lock,
1971 const unsigned char *old_sha1, int mustexist,
1972 struct strbuf *err)
1973{
1974 assert(err);
1975
1976 if (read_ref_full(lock->ref_name,
1977 mustexist ? RESOLVE_REF_READING : 0,
1978 lock->old_oid.hash, NULL)) {
6294dcb4
JK
1979 if (old_sha1) {
1980 int save_errno = errno;
0568c8e9 1981 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
6294dcb4
JK
1982 errno = save_errno;
1983 return -1;
1984 } else {
c368dde9 1985 oidclr(&lock->old_oid);
6294dcb4
JK
1986 return 0;
1987 }
7bd9bcf3 1988 }
6294dcb4 1989 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
0568c8e9 1990 strbuf_addf(err, "ref '%s' is at %s but expected %s",
7bd9bcf3 1991 lock->ref_name,
c368dde9 1992 oid_to_hex(&lock->old_oid),
7bd9bcf3
MH
1993 sha1_to_hex(old_sha1));
1994 errno = EBUSY;
1995 return -1;
1996 }
1997 return 0;
1998}
1999
2000static int remove_empty_directories(struct strbuf *path)
2001{
2002 /*
2003 * we want to create a file but there is a directory there;
2004 * if that is an empty directory (or a directory that contains
2005 * only empty directories), remove them.
2006 */
2007 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
2008}
2009
3b5d3c98
MH
2010static int create_reflock(const char *path, void *cb)
2011{
2012 struct lock_file *lk = cb;
2013
2014 return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;
2015}
2016
7bd9bcf3
MH
2017/*
2018 * Locks a ref returning the lock on success and NULL on failure.
2019 * On failure errno is set to something meaningful.
2020 */
7eb27cdf
MH
2021static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
2022 const char *refname,
7bd9bcf3
MH
2023 const unsigned char *old_sha1,
2024 const struct string_list *extras,
2025 const struct string_list *skip,
bcb497d0 2026 unsigned int flags, int *type,
7bd9bcf3
MH
2027 struct strbuf *err)
2028{
2029 struct strbuf ref_file = STRBUF_INIT;
7bd9bcf3
MH
2030 struct ref_lock *lock;
2031 int last_errno = 0;
7bd9bcf3 2032 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
7a418f3a 2033 int resolve_flags = RESOLVE_REF_NO_RECURSE;
7a418f3a 2034 int resolved;
7bd9bcf3 2035
32c597e7 2036 files_assert_main_repository(refs, "lock_ref_sha1_basic");
7bd9bcf3
MH
2037 assert(err);
2038
2039 lock = xcalloc(1, sizeof(struct ref_lock));
2040
2041 if (mustexist)
2042 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 2043 if (flags & REF_DELETING)
7bd9bcf3 2044 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
7bd9bcf3 2045
7a418f3a
MH
2046 strbuf_git_path(&ref_file, "%s", refname);
2047 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2048 lock->old_oid.hash, type);
2049 if (!resolved && errno == EISDIR) {
7bd9bcf3
MH
2050 /*
2051 * we are trying to lock foo but we used to
2052 * have foo/bar which now does not exist;
2053 * it is normal for the empty directory 'foo'
2054 * to remain.
2055 */
7a418f3a 2056 if (remove_empty_directories(&ref_file)) {
7bd9bcf3 2057 last_errno = errno;
00eebe35
MH
2058 if (!verify_refname_available_dir(
2059 refname, extras, skip,
2060 get_loose_refs(refs), err))
7bd9bcf3 2061 strbuf_addf(err, "there are still refs under '%s'",
7a418f3a 2062 refname);
7bd9bcf3
MH
2063 goto error_return;
2064 }
7a418f3a
MH
2065 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2066 lock->old_oid.hash, type);
7bd9bcf3 2067 }
7a418f3a 2068 if (!resolved) {
7bd9bcf3
MH
2069 last_errno = errno;
2070 if (last_errno != ENOTDIR ||
00eebe35
MH
2071 !verify_refname_available_dir(
2072 refname, extras, skip,
2073 get_loose_refs(refs), err))
0568c8e9 2074 strbuf_addf(err, "unable to resolve reference '%s': %s",
7a418f3a 2075 refname, strerror(last_errno));
7bd9bcf3
MH
2076
2077 goto error_return;
2078 }
2859dcd4 2079
7bd9bcf3
MH
2080 /*
2081 * If the ref did not exist and we are creating it, make sure
2082 * there is no existing packed ref whose name begins with our
2083 * refname, nor a packed ref whose name is a proper prefix of
2084 * our refname.
2085 */
2086 if (is_null_oid(&lock->old_oid) &&
2087 verify_refname_available_dir(refname, extras, skip,
00eebe35
MH
2088 get_packed_refs(refs),
2089 err)) {
7bd9bcf3
MH
2090 last_errno = ENOTDIR;
2091 goto error_return;
2092 }
2093
2094 lock->lk = xcalloc(1, sizeof(struct lock_file));
2095
7bd9bcf3 2096 lock->ref_name = xstrdup(refname);
7bd9bcf3 2097
3b5d3c98 2098 if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
7bd9bcf3 2099 last_errno = errno;
3b5d3c98 2100 unable_to_lock_message(ref_file.buf, errno, err);
7bd9bcf3
MH
2101 goto error_return;
2102 }
2103
6294dcb4 2104 if (verify_lock(lock, old_sha1, mustexist, err)) {
7bd9bcf3
MH
2105 last_errno = errno;
2106 goto error_return;
2107 }
2108 goto out;
2109
2110 error_return:
2111 unlock_ref(lock);
2112 lock = NULL;
2113
2114 out:
2115 strbuf_release(&ref_file);
7bd9bcf3
MH
2116 errno = last_errno;
2117 return lock;
2118}
2119
2120/*
2121 * Write an entry to the packed-refs file for the specified refname.
2122 * If peeled is non-NULL, write it as the entry's peeled value.
2123 */
2124static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2125 unsigned char *peeled)
2126{
2127 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2128 if (peeled)
2129 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2130}
2131
2132/*
2133 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2134 */
2135static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2136{
2137 enum peel_status peel_status = peel_entry(entry, 0);
2138
2139 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2140 error("internal error: %s is not a valid packed reference!",
2141 entry->name);
2142 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2143 peel_status == PEEL_PEELED ?
2144 entry->u.value.peeled.hash : NULL);
2145 return 0;
2146}
2147
2148/*
2149 * Lock the packed-refs file for writing. Flags is passed to
2150 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2151 * errno appropriately and return a nonzero value.
2152 */
49c0df6a 2153static int lock_packed_refs(struct files_ref_store *refs, int flags)
7bd9bcf3
MH
2154{
2155 static int timeout_configured = 0;
2156 static int timeout_value = 1000;
7bd9bcf3
MH
2157 struct packed_ref_cache *packed_ref_cache;
2158
32c597e7 2159 files_assert_main_repository(refs, "lock_packed_refs");
49c0df6a 2160
7bd9bcf3
MH
2161 if (!timeout_configured) {
2162 git_config_get_int("core.packedrefstimeout", &timeout_value);
2163 timeout_configured = 1;
2164 }
2165
2166 if (hold_lock_file_for_update_timeout(
33dfb9f3 2167 &packlock, files_packed_refs_path(refs),
7bd9bcf3
MH
2168 flags, timeout_value) < 0)
2169 return -1;
2170 /*
2171 * Get the current packed-refs while holding the lock. If the
2172 * packed-refs file has been modified since we last read it,
2173 * this will automatically invalidate the cache and re-read
2174 * the packed-refs file.
2175 */
00eebe35 2176 packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
2177 packed_ref_cache->lock = &packlock;
2178 /* Increment the reference count to prevent it from being freed: */
2179 acquire_packed_ref_cache(packed_ref_cache);
2180 return 0;
2181}
2182
2183/*
2184 * Write the current version of the packed refs cache from memory to
2185 * disk. The packed-refs file must already be locked for writing (see
2186 * lock_packed_refs()). Return zero on success. On errors, set errno
2187 * and return a nonzero value
2188 */
49c0df6a 2189static int commit_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2190{
2191 struct packed_ref_cache *packed_ref_cache =
00eebe35 2192 get_packed_ref_cache(refs);
7bd9bcf3
MH
2193 int error = 0;
2194 int save_errno = 0;
2195 FILE *out;
2196
32c597e7 2197 files_assert_main_repository(refs, "commit_packed_refs");
49c0df6a 2198
7bd9bcf3
MH
2199 if (!packed_ref_cache->lock)
2200 die("internal error: packed-refs not locked");
2201
2202 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2203 if (!out)
2204 die_errno("unable to fdopen packed-refs descriptor");
2205
2206 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2207 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2208 0, write_packed_entry_fn, out);
2209
2210 if (commit_lock_file(packed_ref_cache->lock)) {
2211 save_errno = errno;
2212 error = -1;
2213 }
2214 packed_ref_cache->lock = NULL;
2215 release_packed_ref_cache(packed_ref_cache);
2216 errno = save_errno;
2217 return error;
2218}
2219
2220/*
2221 * Rollback the lockfile for the packed-refs file, and discard the
2222 * in-memory packed reference cache. (The packed-refs file will be
2223 * read anew if it is needed again after this function is called.)
2224 */
49c0df6a 2225static void rollback_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2226{
2227 struct packed_ref_cache *packed_ref_cache =
00eebe35 2228 get_packed_ref_cache(refs);
7bd9bcf3 2229
32c597e7 2230 files_assert_main_repository(refs, "rollback_packed_refs");
7bd9bcf3
MH
2231
2232 if (!packed_ref_cache->lock)
2233 die("internal error: packed-refs not locked");
2234 rollback_lock_file(packed_ref_cache->lock);
2235 packed_ref_cache->lock = NULL;
2236 release_packed_ref_cache(packed_ref_cache);
00eebe35 2237 clear_packed_ref_cache(refs);
7bd9bcf3
MH
2238}
2239
2240struct ref_to_prune {
2241 struct ref_to_prune *next;
2242 unsigned char sha1[20];
2243 char name[FLEX_ARRAY];
2244};
2245
2246struct pack_refs_cb_data {
2247 unsigned int flags;
2248 struct ref_dir *packed_refs;
2249 struct ref_to_prune *ref_to_prune;
2250};
2251
2252/*
2253 * An each_ref_entry_fn that is run over loose references only. If
2254 * the loose reference can be packed, add an entry in the packed ref
2255 * cache. If the reference should be pruned, also add it to
2256 * ref_to_prune in the pack_refs_cb_data.
2257 */
2258static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2259{
2260 struct pack_refs_cb_data *cb = cb_data;
2261 enum peel_status peel_status;
2262 struct ref_entry *packed_entry;
2263 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2264
2265 /* Do not pack per-worktree refs: */
2266 if (ref_type(entry->name) != REF_TYPE_NORMAL)
2267 return 0;
2268
2269 /* ALWAYS pack tags */
2270 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2271 return 0;
2272
2273 /* Do not pack symbolic or broken refs: */
ffeef642 2274 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))
7bd9bcf3
MH
2275 return 0;
2276
2277 /* Add a packed ref cache entry equivalent to the loose entry. */
2278 peel_status = peel_entry(entry, 1);
2279 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2280 die("internal error peeling reference %s (%s)",
2281 entry->name, oid_to_hex(&entry->u.value.oid));
2282 packed_entry = find_ref(cb->packed_refs, entry->name);
2283 if (packed_entry) {
2284 /* Overwrite existing packed entry with info from loose entry */
2285 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2286 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2287 } else {
2288 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2289 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2290 add_ref(cb->packed_refs, packed_entry);
2291 }
2292 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2293
2294 /* Schedule the loose reference for pruning if requested. */
2295 if ((cb->flags & PACK_REFS_PRUNE)) {
96ffc06f
JK
2296 struct ref_to_prune *n;
2297 FLEX_ALLOC_STR(n, name, entry->name);
7bd9bcf3 2298 hashcpy(n->sha1, entry->u.value.oid.hash);
7bd9bcf3
MH
2299 n->next = cb->ref_to_prune;
2300 cb->ref_to_prune = n;
2301 }
2302 return 0;
2303}
2304
a8f0db2d
MH
2305enum {
2306 REMOVE_EMPTY_PARENTS_REF = 0x01,
2307 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
2308};
2309
7bd9bcf3 2310/*
a8f0db2d
MH
2311 * Remove empty parent directories associated with the specified
2312 * reference and/or its reflog, but spare [logs/]refs/ and immediate
2313 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
2314 * REMOVE_EMPTY_PARENTS_REFLOG.
7bd9bcf3 2315 */
a8f0db2d 2316static void try_remove_empty_parents(const char *refname, unsigned int flags)
7bd9bcf3 2317{
8bdaecb4 2318 struct strbuf buf = STRBUF_INIT;
7bd9bcf3
MH
2319 char *p, *q;
2320 int i;
8bdaecb4
MH
2321
2322 strbuf_addstr(&buf, refname);
2323 p = buf.buf;
7bd9bcf3
MH
2324 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2325 while (*p && *p != '/')
2326 p++;
2327 /* tolerate duplicate slashes; see check_refname_format() */
2328 while (*p == '/')
2329 p++;
2330 }
8bdaecb4 2331 q = buf.buf + buf.len;
a8f0db2d 2332 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
7bd9bcf3
MH
2333 while (q > p && *q != '/')
2334 q--;
2335 while (q > p && *(q-1) == '/')
2336 q--;
2337 if (q == p)
2338 break;
8bdaecb4 2339 strbuf_setlen(&buf, q - buf.buf);
a8f0db2d
MH
2340 if ((flags & REMOVE_EMPTY_PARENTS_REF) &&
2341 rmdir(git_path("%s", buf.buf)))
2342 flags &= ~REMOVE_EMPTY_PARENTS_REF;
2343 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) &&
2344 rmdir(git_path("logs/%s", buf.buf)))
2345 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
7bd9bcf3 2346 }
8bdaecb4 2347 strbuf_release(&buf);
7bd9bcf3
MH
2348}
2349
2350/* make sure nobody touched the ref, and unlink */
2351static void prune_ref(struct ref_to_prune *r)
2352{
2353 struct ref_transaction *transaction;
2354 struct strbuf err = STRBUF_INIT;
2355
2356 if (check_refname_format(r->name, 0))
2357 return;
2358
2359 transaction = ref_transaction_begin(&err);
2360 if (!transaction ||
2361 ref_transaction_delete(transaction, r->name, r->sha1,
c52ce248 2362 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
7bd9bcf3
MH
2363 ref_transaction_commit(transaction, &err)) {
2364 ref_transaction_free(transaction);
2365 error("%s", err.buf);
2366 strbuf_release(&err);
2367 return;
2368 }
2369 ref_transaction_free(transaction);
2370 strbuf_release(&err);
7bd9bcf3
MH
2371}
2372
2373static void prune_refs(struct ref_to_prune *r)
2374{
2375 while (r) {
2376 prune_ref(r);
2377 r = r->next;
2378 }
2379}
2380
8231527e 2381static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
7bd9bcf3 2382{
00eebe35 2383 struct files_ref_store *refs =
8231527e 2384 files_downcast(ref_store, 0, "pack_refs");
7bd9bcf3
MH
2385 struct pack_refs_cb_data cbdata;
2386
2387 memset(&cbdata, 0, sizeof(cbdata));
2388 cbdata.flags = flags;
2389
49c0df6a 2390 lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
00eebe35 2391 cbdata.packed_refs = get_packed_refs(refs);
7bd9bcf3 2392
00eebe35 2393 do_for_each_entry_in_dir(get_loose_refs(refs), 0,
7bd9bcf3
MH
2394 pack_if_possible_fn, &cbdata);
2395
49c0df6a 2396 if (commit_packed_refs(refs))
7bd9bcf3
MH
2397 die_errno("unable to overwrite old ref-pack file");
2398
2399 prune_refs(cbdata.ref_to_prune);
2400 return 0;
2401}
2402
2403/*
2404 * Rewrite the packed-refs file, omitting any refs listed in
2405 * 'refnames'. On error, leave packed-refs unchanged, write an error
2406 * message to 'err', and return a nonzero value.
2407 *
2408 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2409 */
0a95ac5f
MH
2410static int repack_without_refs(struct files_ref_store *refs,
2411 struct string_list *refnames, struct strbuf *err)
7bd9bcf3
MH
2412{
2413 struct ref_dir *packed;
2414 struct string_list_item *refname;
2415 int ret, needs_repacking = 0, removed = 0;
2416
32c597e7 2417 files_assert_main_repository(refs, "repack_without_refs");
7bd9bcf3
MH
2418 assert(err);
2419
2420 /* Look for a packed ref */
2421 for_each_string_list_item(refname, refnames) {
f0d21efc 2422 if (get_packed_ref(refs, refname->string)) {
7bd9bcf3
MH
2423 needs_repacking = 1;
2424 break;
2425 }
2426 }
2427
2428 /* Avoid locking if we have nothing to do */
2429 if (!needs_repacking)
2430 return 0; /* no refname exists in packed refs */
2431
49c0df6a 2432 if (lock_packed_refs(refs, 0)) {
33dfb9f3 2433 unable_to_lock_message(files_packed_refs_path(refs), errno, err);
7bd9bcf3
MH
2434 return -1;
2435 }
00eebe35 2436 packed = get_packed_refs(refs);
7bd9bcf3
MH
2437
2438 /* Remove refnames from the cache */
2439 for_each_string_list_item(refname, refnames)
2440 if (remove_entry(packed, refname->string) != -1)
2441 removed = 1;
2442 if (!removed) {
2443 /*
2444 * All packed entries disappeared while we were
2445 * acquiring the lock.
2446 */
49c0df6a 2447 rollback_packed_refs(refs);
7bd9bcf3
MH
2448 return 0;
2449 }
2450
2451 /* Write what remains */
49c0df6a 2452 ret = commit_packed_refs(refs);
7bd9bcf3
MH
2453 if (ret)
2454 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2455 strerror(errno));
2456 return ret;
2457}
2458
a27dcf89
DT
2459static int files_delete_refs(struct ref_store *ref_store,
2460 struct string_list *refnames, unsigned int flags)
7bd9bcf3 2461{
0a95ac5f 2462 struct files_ref_store *refs =
a27dcf89 2463 files_downcast(ref_store, 0, "delete_refs");
7bd9bcf3
MH
2464 struct strbuf err = STRBUF_INIT;
2465 int i, result = 0;
2466
2467 if (!refnames->nr)
2468 return 0;
2469
0a95ac5f 2470 result = repack_without_refs(refs, refnames, &err);
7bd9bcf3
MH
2471 if (result) {
2472 /*
2473 * If we failed to rewrite the packed-refs file, then
2474 * it is unsafe to try to remove loose refs, because
2475 * doing so might expose an obsolete packed value for
2476 * a reference that might even point at an object that
2477 * has been garbage collected.
2478 */
2479 if (refnames->nr == 1)
2480 error(_("could not delete reference %s: %s"),
2481 refnames->items[0].string, err.buf);
2482 else
2483 error(_("could not delete references: %s"), err.buf);
2484
2485 goto out;
2486 }
2487
2488 for (i = 0; i < refnames->nr; i++) {
2489 const char *refname = refnames->items[i].string;
2490
755b49ae 2491 if (delete_ref(NULL, refname, NULL, flags))
7bd9bcf3
MH
2492 result |= error(_("could not remove reference %s"), refname);
2493 }
2494
2495out:
2496 strbuf_release(&err);
2497 return result;
2498}
2499
2500/*
2501 * People using contrib's git-new-workdir have .git/logs/refs ->
2502 * /some/other/path/.git/logs/refs, and that may live on another device.
2503 *
2504 * IOW, to avoid cross device rename errors, the temporary renamed log must
2505 * live into logs/refs.
2506 */
2507#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2508
6a7f3631 2509static int rename_tmp_log_callback(const char *path, void *cb)
7bd9bcf3 2510{
6a7f3631 2511 int *true_errno = cb;
7bd9bcf3 2512
6a7f3631
MH
2513 if (rename(git_path(TMP_RENAMED_LOG), path)) {
2514 /*
2515 * rename(a, b) when b is an existing directory ought
2516 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
2517 * Sheesh. Record the true errno for error reporting,
2518 * but report EISDIR to raceproof_create_file() so
2519 * that it knows to retry.
2520 */
2521 *true_errno = errno;
2522 if (errno == ENOTDIR)
2523 errno = EISDIR;
2524 return -1;
2525 } else {
2526 return 0;
7bd9bcf3 2527 }
6a7f3631 2528}
7bd9bcf3 2529
6a7f3631
MH
2530static int rename_tmp_log(const char *newrefname)
2531{
2532 char *path = git_pathdup("logs/%s", newrefname);
2533 int ret, true_errno;
2534
2535 ret = raceproof_create_file(path, rename_tmp_log_callback, &true_errno);
2536 if (ret) {
2537 if (errno == EISDIR)
990c98d2 2538 error("directory not empty: %s", path);
6a7f3631 2539 else
990c98d2
MH
2540 error("unable to move logfile %s to %s: %s",
2541 git_path(TMP_RENAMED_LOG), path,
2542 strerror(true_errno));
7bd9bcf3 2543 }
6a7f3631
MH
2544
2545 free(path);
7bd9bcf3
MH
2546 return ret;
2547}
2548
62665823
MH
2549static int files_verify_refname_available(struct ref_store *ref_store,
2550 const char *newname,
2551 const struct string_list *extras,
2552 const struct string_list *skip,
2553 struct strbuf *err)
7bd9bcf3 2554{
00eebe35 2555 struct files_ref_store *refs =
62665823 2556 files_downcast(ref_store, 1, "verify_refname_available");
00eebe35
MH
2557 struct ref_dir *packed_refs = get_packed_refs(refs);
2558 struct ref_dir *loose_refs = get_loose_refs(refs);
7bd9bcf3
MH
2559
2560 if (verify_refname_available_dir(newname, extras, skip,
2561 packed_refs, err) ||
2562 verify_refname_available_dir(newname, extras, skip,
2563 loose_refs, err))
2564 return -1;
2565
2566 return 0;
2567}
2568
7bd9bcf3
MH
2569static int write_ref_to_lockfile(struct ref_lock *lock,
2570 const unsigned char *sha1, struct strbuf *err);
f18a7892
MH
2571static int commit_ref_update(struct files_ref_store *refs,
2572 struct ref_lock *lock,
7bd9bcf3 2573 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2574 struct strbuf *err);
7bd9bcf3 2575
9b6b40d9
DT
2576static int files_rename_ref(struct ref_store *ref_store,
2577 const char *oldrefname, const char *newrefname,
2578 const char *logmsg)
7bd9bcf3 2579{
9b6b40d9
DT
2580 struct files_ref_store *refs =
2581 files_downcast(ref_store, 0, "rename_ref");
7bd9bcf3
MH
2582 unsigned char sha1[20], orig_sha1[20];
2583 int flag = 0, logmoved = 0;
2584 struct ref_lock *lock;
2585 struct stat loginfo;
2586 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
7bd9bcf3
MH
2587 struct strbuf err = STRBUF_INIT;
2588
2589 if (log && S_ISLNK(loginfo.st_mode))
2590 return error("reflog for %s is a symlink", oldrefname);
2591
12fd3496
DT
2592 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2593 orig_sha1, &flag))
e711b1af
MH
2594 return error("refname %s not found", oldrefname);
2595
7bd9bcf3
MH
2596 if (flag & REF_ISSYMREF)
2597 return error("refname %s is a symbolic ref, renaming it is not supported",
2598 oldrefname);
7bd9bcf3
MH
2599 if (!rename_ref_available(oldrefname, newrefname))
2600 return 1;
2601
2602 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2603 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2604 oldrefname, strerror(errno));
2605
893dbf5b 2606 if (delete_ref(logmsg, oldrefname, orig_sha1, REF_NODEREF)) {
7bd9bcf3
MH
2607 error("unable to delete old %s", oldrefname);
2608 goto rollback;
2609 }
2610
12fd3496
DT
2611 /*
2612 * Since we are doing a shallow lookup, sha1 is not the
2613 * correct value to pass to delete_ref as old_sha1. But that
2614 * doesn't matter, because an old_sha1 check wouldn't add to
2615 * the safety anyway; we want to delete the reference whatever
2616 * its current value.
2617 */
2618 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2619 sha1, NULL) &&
755b49ae 2620 delete_ref(NULL, newrefname, NULL, REF_NODEREF)) {
58364324 2621 if (errno == EISDIR) {
7bd9bcf3
MH
2622 struct strbuf path = STRBUF_INIT;
2623 int result;
2624
2625 strbuf_git_path(&path, "%s", newrefname);
2626 result = remove_empty_directories(&path);
2627 strbuf_release(&path);
2628
2629 if (result) {
2630 error("Directory not empty: %s", newrefname);
2631 goto rollback;
2632 }
2633 } else {
2634 error("unable to delete existing %s", newrefname);
2635 goto rollback;
2636 }
2637 }
2638
2639 if (log && rename_tmp_log(newrefname))
2640 goto rollback;
2641
2642 logmoved = log;
2643
7eb27cdf
MH
2644 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
2645 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
2646 if (!lock) {
2647 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2648 strbuf_release(&err);
2649 goto rollback;
2650 }
2651 hashcpy(lock->old_oid.hash, orig_sha1);
2652
2653 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 2654 commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {
7bd9bcf3
MH
2655 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
2656 strbuf_release(&err);
2657 goto rollback;
2658 }
2659
2660 return 0;
2661
2662 rollback:
7eb27cdf
MH
2663 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
2664 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
2665 if (!lock) {
2666 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2667 strbuf_release(&err);
2668 goto rollbacklog;
2669 }
2670
2671 flag = log_all_ref_updates;
341fb286 2672 log_all_ref_updates = LOG_REFS_NONE;
7bd9bcf3 2673 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 2674 commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {
7bd9bcf3
MH
2675 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
2676 strbuf_release(&err);
2677 }
2678 log_all_ref_updates = flag;
2679
2680 rollbacklog:
2681 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2682 error("unable to restore logfile %s from %s: %s",
2683 oldrefname, newrefname, strerror(errno));
2684 if (!logmoved && log &&
2685 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2686 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2687 oldrefname, strerror(errno));
2688
2689 return 1;
2690}
2691
2692static int close_ref(struct ref_lock *lock)
2693{
2694 if (close_lock_file(lock->lk))
2695 return -1;
2696 return 0;
2697}
2698
2699static int commit_ref(struct ref_lock *lock)
2700{
5387c0d8
MH
2701 char *path = get_locked_file_path(lock->lk);
2702 struct stat st;
2703
2704 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
2705 /*
2706 * There is a directory at the path we want to rename
2707 * the lockfile to. Hopefully it is empty; try to
2708 * delete it.
2709 */
2710 size_t len = strlen(path);
2711 struct strbuf sb_path = STRBUF_INIT;
2712
2713 strbuf_attach(&sb_path, path, len, len);
2714
2715 /*
2716 * If this fails, commit_lock_file() will also fail
2717 * and will report the problem.
2718 */
2719 remove_empty_directories(&sb_path);
2720 strbuf_release(&sb_path);
2721 } else {
2722 free(path);
2723 }
2724
7bd9bcf3
MH
2725 if (commit_lock_file(lock->lk))
2726 return -1;
2727 return 0;
2728}
2729
1fb0c809
MH
2730static int open_or_create_logfile(const char *path, void *cb)
2731{
2732 int *fd = cb;
2733
2734 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
2735 return (*fd < 0) ? -1 : 0;
2736}
2737
7bd9bcf3 2738/*
4533e534
MH
2739 * Create a reflog for a ref. If force_create = 0, only create the
2740 * reflog for certain refs (those for which should_autocreate_reflog
2741 * returns non-zero). Otherwise, create it regardless of the reference
2742 * name. If the logfile already existed or was created, return 0 and
2743 * set *logfd to the file descriptor opened for appending to the file.
2744 * If no logfile exists and we decided not to create one, return 0 and
2745 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
2746 * return -1.
7bd9bcf3 2747 */
4533e534
MH
2748static int log_ref_setup(const char *refname, int force_create,
2749 int *logfd, struct strbuf *err)
7bd9bcf3 2750{
4533e534 2751 char *logfile = git_pathdup("logs/%s", refname);
7bd9bcf3 2752
7bd9bcf3 2753 if (force_create || should_autocreate_reflog(refname)) {
4533e534 2754 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1fb0c809
MH
2755 if (errno == ENOENT)
2756 strbuf_addf(err, "unable to create directory for '%s': "
4533e534 2757 "%s", logfile, strerror(errno));
1fb0c809
MH
2758 else if (errno == EISDIR)
2759 strbuf_addf(err, "there are still logs under '%s'",
4533e534 2760 logfile);
1fb0c809 2761 else
854bda6b 2762 strbuf_addf(err, "unable to append to '%s': %s",
4533e534 2763 logfile, strerror(errno));
7bd9bcf3 2764
4533e534 2765 goto error;
7bd9bcf3 2766 }
854bda6b 2767 } else {
4533e534 2768 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
e404f459 2769 if (*logfd < 0) {
854bda6b
MH
2770 if (errno == ENOENT || errno == EISDIR) {
2771 /*
2772 * The logfile doesn't already exist,
2773 * but that is not an error; it only
2774 * means that we won't write log
2775 * entries to it.
2776 */
2777 ;
2778 } else {
2779 strbuf_addf(err, "unable to append to '%s': %s",
4533e534
MH
2780 logfile, strerror(errno));
2781 goto error;
854bda6b 2782 }
7bd9bcf3
MH
2783 }
2784 }
2785
e404f459 2786 if (*logfd >= 0)
4533e534 2787 adjust_shared_perm(logfile);
854bda6b 2788
4533e534 2789 free(logfile);
7bd9bcf3 2790 return 0;
7bd9bcf3 2791
4533e534
MH
2792error:
2793 free(logfile);
2794 return -1;
7bd9bcf3 2795}
7bd9bcf3 2796
e3688bd6
DT
2797static int files_create_reflog(struct ref_store *ref_store,
2798 const char *refname, int force_create,
2799 struct strbuf *err)
7bd9bcf3 2800{
e404f459 2801 int fd;
7bd9bcf3 2802
e3688bd6
DT
2803 /* Check validity (but we don't need the result): */
2804 files_downcast(ref_store, 0, "create_reflog");
2805
4533e534
MH
2806 if (log_ref_setup(refname, force_create, &fd, err))
2807 return -1;
2808
e404f459
MH
2809 if (fd >= 0)
2810 close(fd);
4533e534
MH
2811
2812 return 0;
7bd9bcf3
MH
2813}
2814
2815static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2816 const unsigned char *new_sha1,
2817 const char *committer, const char *msg)
2818{
2819 int msglen, written;
2820 unsigned maxlen, len;
2821 char *logrec;
2822
2823 msglen = msg ? strlen(msg) : 0;
2824 maxlen = strlen(committer) + msglen + 100;
2825 logrec = xmalloc(maxlen);
2826 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2827 sha1_to_hex(old_sha1),
2828 sha1_to_hex(new_sha1),
2829 committer);
2830 if (msglen)
2831 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2832
2833 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2834 free(logrec);
2835 if (written != len)
2836 return -1;
2837
2838 return 0;
2839}
2840
11f8457f
NTND
2841static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
2842 const unsigned char *new_sha1, const char *msg,
2843 int flags, struct strbuf *err)
7bd9bcf3 2844{
e404f459 2845 int logfd, result;
7bd9bcf3 2846
341fb286
CW
2847 if (log_all_ref_updates == LOG_REFS_UNSET)
2848 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
7bd9bcf3 2849
4533e534
MH
2850 result = log_ref_setup(refname, flags & REF_FORCE_CREATE_REFLOG,
2851 &logfd, err);
7bd9bcf3
MH
2852
2853 if (result)
2854 return result;
2855
7bd9bcf3
MH
2856 if (logfd < 0)
2857 return 0;
2858 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2859 git_committer_info(0), msg);
2860 if (result) {
87b21e05
MH
2861 int save_errno = errno;
2862
2863 strbuf_addf(err, "unable to append to '%s': %s",
2864 git_path("logs/%s", refname), strerror(save_errno));
7bd9bcf3
MH
2865 close(logfd);
2866 return -1;
2867 }
2868 if (close(logfd)) {
87b21e05
MH
2869 int save_errno = errno;
2870
2871 strbuf_addf(err, "unable to append to '%s': %s",
2872 git_path("logs/%s", refname), strerror(save_errno));
7bd9bcf3
MH
2873 return -1;
2874 }
2875 return 0;
2876}
2877
7bd9bcf3
MH
2878/*
2879 * Write sha1 into the open lockfile, then close the lockfile. On
2880 * errors, rollback the lockfile, fill in *err and
2881 * return -1.
2882 */
2883static int write_ref_to_lockfile(struct ref_lock *lock,
2884 const unsigned char *sha1, struct strbuf *err)
2885{
2886 static char term = '\n';
2887 struct object *o;
2888 int fd;
2889
2890 o = parse_object(sha1);
2891 if (!o) {
2892 strbuf_addf(err,
0568c8e9 2893 "trying to write ref '%s' with nonexistent object %s",
7bd9bcf3
MH
2894 lock->ref_name, sha1_to_hex(sha1));
2895 unlock_ref(lock);
2896 return -1;
2897 }
2898 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2899 strbuf_addf(err,
0568c8e9 2900 "trying to write non-commit object %s to branch '%s'",
7bd9bcf3
MH
2901 sha1_to_hex(sha1), lock->ref_name);
2902 unlock_ref(lock);
2903 return -1;
2904 }
2905 fd = get_lock_file_fd(lock->lk);
2906 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
2907 write_in_full(fd, &term, 1) != 1 ||
2908 close_ref(lock) < 0) {
2909 strbuf_addf(err,
0568c8e9 2910 "couldn't write '%s'", get_lock_file_path(lock->lk));
7bd9bcf3
MH
2911 unlock_ref(lock);
2912 return -1;
2913 }
2914 return 0;
2915}
2916
2917/*
2918 * Commit a change to a loose reference that has already been written
2919 * to the loose reference lockfile. Also update the reflogs if
2920 * necessary, using the specified lockmsg (which can be NULL).
2921 */
f18a7892
MH
2922static int commit_ref_update(struct files_ref_store *refs,
2923 struct ref_lock *lock,
7bd9bcf3 2924 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2925 struct strbuf *err)
7bd9bcf3 2926{
32c597e7 2927 files_assert_main_repository(refs, "commit_ref_update");
00eebe35
MH
2928
2929 clear_loose_ref_cache(refs);
81b1b6d4
MH
2930 if (files_log_ref_write(lock->ref_name, lock->old_oid.hash, sha1,
2931 logmsg, 0, err)) {
7bd9bcf3 2932 char *old_msg = strbuf_detach(err, NULL);
0568c8e9 2933 strbuf_addf(err, "cannot update the ref '%s': %s",
7bd9bcf3
MH
2934 lock->ref_name, old_msg);
2935 free(old_msg);
2936 unlock_ref(lock);
2937 return -1;
2938 }
7a418f3a
MH
2939
2940 if (strcmp(lock->ref_name, "HEAD") != 0) {
7bd9bcf3
MH
2941 /*
2942 * Special hack: If a branch is updated directly and HEAD
2943 * points to it (may happen on the remote side of a push
2944 * for example) then logically the HEAD reflog should be
2945 * updated too.
2946 * A generic solution implies reverse symref information,
2947 * but finding all symrefs pointing to the given branch
2948 * would be rather costly for this rare event (the direct
2949 * update of a branch) to be worth it. So let's cheat and
2950 * check with HEAD only which should cover 99% of all usage
2951 * scenarios (even 100% of the default ones).
2952 */
2953 unsigned char head_sha1[20];
2954 int head_flag;
2955 const char *head_ref;
7a418f3a 2956
7bd9bcf3
MH
2957 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
2958 head_sha1, &head_flag);
2959 if (head_ref && (head_flag & REF_ISSYMREF) &&
2960 !strcmp(head_ref, lock->ref_name)) {
2961 struct strbuf log_err = STRBUF_INIT;
81b1b6d4 2962 if (files_log_ref_write("HEAD", lock->old_oid.hash, sha1,
7bd9bcf3
MH
2963 logmsg, 0, &log_err)) {
2964 error("%s", log_err.buf);
2965 strbuf_release(&log_err);
2966 }
2967 }
2968 }
7a418f3a 2969
7bd9bcf3 2970 if (commit_ref(lock)) {
0568c8e9 2971 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
7bd9bcf3
MH
2972 unlock_ref(lock);
2973 return -1;
2974 }
2975
2976 unlock_ref(lock);
2977 return 0;
2978}
2979
370e5ad6 2980static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 2981{
370e5ad6 2982 int ret = -1;
7bd9bcf3 2983#ifndef NO_SYMLINK_HEAD
370e5ad6
JK
2984 char *ref_path = get_locked_file_path(lock->lk);
2985 unlink(ref_path);
2986 ret = symlink(target, ref_path);
2987 free(ref_path);
2988
2989 if (ret)
7bd9bcf3 2990 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 2991#endif
370e5ad6
JK
2992 return ret;
2993}
7bd9bcf3 2994
370e5ad6
JK
2995static void update_symref_reflog(struct ref_lock *lock, const char *refname,
2996 const char *target, const char *logmsg)
2997{
2998 struct strbuf err = STRBUF_INIT;
2999 unsigned char new_sha1[20];
b9badadd 3000 if (logmsg && !read_ref(target, new_sha1) &&
81b1b6d4
MH
3001 files_log_ref_write(refname, lock->old_oid.hash, new_sha1,
3002 logmsg, 0, &err)) {
7bd9bcf3
MH
3003 error("%s", err.buf);
3004 strbuf_release(&err);
3005 }
370e5ad6 3006}
7bd9bcf3 3007
370e5ad6
JK
3008static int create_symref_locked(struct ref_lock *lock, const char *refname,
3009 const char *target, const char *logmsg)
3010{
3011 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
3012 update_symref_reflog(lock, refname, target, logmsg);
3013 return 0;
3014 }
3015
3016 if (!fdopen_lock_file(lock->lk, "w"))
3017 return error("unable to fdopen %s: %s",
3018 lock->lk->tempfile.filename.buf, strerror(errno));
3019
396da8f7
JK
3020 update_symref_reflog(lock, refname, target, logmsg);
3021
370e5ad6
JK
3022 /* no error check; commit_ref will check ferror */
3023 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
3024 if (commit_ref(lock) < 0)
3025 return error("unable to write symref for %s: %s", refname,
3026 strerror(errno));
7bd9bcf3
MH
3027 return 0;
3028}
3029
284689ba
MH
3030static int files_create_symref(struct ref_store *ref_store,
3031 const char *refname, const char *target,
3032 const char *logmsg)
370e5ad6 3033{
7eb27cdf
MH
3034 struct files_ref_store *refs =
3035 files_downcast(ref_store, 0, "create_symref");
370e5ad6
JK
3036 struct strbuf err = STRBUF_INIT;
3037 struct ref_lock *lock;
3038 int ret;
3039
7eb27cdf
MH
3040 lock = lock_ref_sha1_basic(refs, refname, NULL,
3041 NULL, NULL, REF_NODEREF, NULL,
370e5ad6
JK
3042 &err);
3043 if (!lock) {
3044 error("%s", err.buf);
3045 strbuf_release(&err);
3046 return -1;
3047 }
3048
3049 ret = create_symref_locked(lock, refname, target, logmsg);
3050 unlock_ref(lock);
3051 return ret;
3052}
3053
39ee4c6c 3054int set_worktree_head_symref(const char *gitdir, const char *target, const char *logmsg)
2233066e
KY
3055{
3056 static struct lock_file head_lock;
3057 struct ref_lock *lock;
2233066e
KY
3058 struct strbuf head_path = STRBUF_INIT;
3059 const char *head_rel;
3060 int ret;
3061
3062 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));
3063 if (hold_lock_file_for_update(&head_lock, head_path.buf,
3064 LOCK_NO_DEREF) < 0) {
18eb3a9c
KY
3065 struct strbuf err = STRBUF_INIT;
3066 unable_to_lock_message(head_path.buf, errno, &err);
2233066e
KY
3067 error("%s", err.buf);
3068 strbuf_release(&err);
3069 strbuf_release(&head_path);
3070 return -1;
3071 }
3072
3073 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for
3074 linked trees */
3075 head_rel = remove_leading_path(head_path.buf,
3076 absolute_path(get_git_common_dir()));
3077 /* to make use of create_symref_locked(), initialize ref_lock */
3078 lock = xcalloc(1, sizeof(struct ref_lock));
3079 lock->lk = &head_lock;
3080 lock->ref_name = xstrdup(head_rel);
2233066e 3081
39ee4c6c 3082 ret = create_symref_locked(lock, head_rel, target, logmsg);
2233066e
KY
3083
3084 unlock_ref(lock); /* will free lock */
3085 strbuf_release(&head_path);
3086 return ret;
3087}
3088
e3688bd6
DT
3089static int files_reflog_exists(struct ref_store *ref_store,
3090 const char *refname)
7bd9bcf3
MH
3091{
3092 struct stat st;
3093
e3688bd6
DT
3094 /* Check validity (but we don't need the result): */
3095 files_downcast(ref_store, 0, "reflog_exists");
3096
7bd9bcf3
MH
3097 return !lstat(git_path("logs/%s", refname), &st) &&
3098 S_ISREG(st.st_mode);
3099}
3100
e3688bd6
DT
3101static int files_delete_reflog(struct ref_store *ref_store,
3102 const char *refname)
7bd9bcf3 3103{
e3688bd6
DT
3104 /* Check validity (but we don't need the result): */
3105 files_downcast(ref_store, 0, "delete_reflog");
3106
7bd9bcf3
MH
3107 return remove_path(git_path("logs/%s", refname));
3108}
3109
3110static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3111{
9461d272 3112 struct object_id ooid, noid;
7bd9bcf3
MH
3113 char *email_end, *message;
3114 unsigned long timestamp;
3115 int tz;
43bc3b6c 3116 const char *p = sb->buf;
7bd9bcf3
MH
3117
3118 /* old SP new SP name <email> SP time TAB msg LF */
43bc3b6c 3119 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
3120 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
3121 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
3122 !(email_end = strchr(p, '>')) ||
7bd9bcf3
MH
3123 email_end[1] != ' ' ||
3124 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3125 !message || message[0] != ' ' ||
3126 (message[1] != '+' && message[1] != '-') ||
3127 !isdigit(message[2]) || !isdigit(message[3]) ||
3128 !isdigit(message[4]) || !isdigit(message[5]))
3129 return 0; /* corrupt? */
3130 email_end[1] = '\0';
3131 tz = strtol(message + 1, NULL, 10);
3132 if (message[6] != '\t')
3133 message += 6;
3134 else
3135 message += 7;
43bc3b6c 3136 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
7bd9bcf3
MH
3137}
3138
3139static char *find_beginning_of_line(char *bob, char *scan)
3140{
3141 while (bob < scan && *(--scan) != '\n')
3142 ; /* keep scanning backwards */
3143 /*
3144 * Return either beginning of the buffer, or LF at the end of
3145 * the previous line.
3146 */
3147 return scan;
3148}
3149
e3688bd6
DT
3150static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
3151 const char *refname,
3152 each_reflog_ent_fn fn,
3153 void *cb_data)
7bd9bcf3
MH
3154{
3155 struct strbuf sb = STRBUF_INIT;
3156 FILE *logfp;
3157 long pos;
3158 int ret = 0, at_tail = 1;
3159
e3688bd6
DT
3160 /* Check validity (but we don't need the result): */
3161 files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
3162
7bd9bcf3
MH
3163 logfp = fopen(git_path("logs/%s", refname), "r");
3164 if (!logfp)
3165 return -1;
3166
3167 /* Jump to the end */
3168 if (fseek(logfp, 0, SEEK_END) < 0)
3169 return error("cannot seek back reflog for %s: %s",
3170 refname, strerror(errno));
3171 pos = ftell(logfp);
3172 while (!ret && 0 < pos) {
3173 int cnt;
3174 size_t nread;
3175 char buf[BUFSIZ];
3176 char *endp, *scanp;
3177
3178 /* Fill next block from the end */
3179 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3180 if (fseek(logfp, pos - cnt, SEEK_SET))
3181 return error("cannot seek back reflog for %s: %s",
3182 refname, strerror(errno));
3183 nread = fread(buf, cnt, 1, logfp);
3184 if (nread != 1)
3185 return error("cannot read %d bytes from reflog for %s: %s",
3186 cnt, refname, strerror(errno));
3187 pos -= cnt;
3188
3189 scanp = endp = buf + cnt;
3190 if (at_tail && scanp[-1] == '\n')
3191 /* Looking at the final LF at the end of the file */
3192 scanp--;
3193 at_tail = 0;
3194
3195 while (buf < scanp) {
3196 /*
3197 * terminating LF of the previous line, or the beginning
3198 * of the buffer.
3199 */
3200 char *bp;
3201
3202 bp = find_beginning_of_line(buf, scanp);
3203
3204 if (*bp == '\n') {
3205 /*
3206 * The newline is the end of the previous line,
3207 * so we know we have complete line starting
3208 * at (bp + 1). Prefix it onto any prior data
3209 * we collected for the line and process it.
3210 */
3211 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3212 scanp = bp;
3213 endp = bp + 1;
3214 ret = show_one_reflog_ent(&sb, fn, cb_data);
3215 strbuf_reset(&sb);
3216 if (ret)
3217 break;
3218 } else if (!pos) {
3219 /*
3220 * We are at the start of the buffer, and the
3221 * start of the file; there is no previous
3222 * line, and we have everything for this one.
3223 * Process it, and we can end the loop.
3224 */
3225 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3226 ret = show_one_reflog_ent(&sb, fn, cb_data);
3227 strbuf_reset(&sb);
3228 break;
3229 }
3230
3231 if (bp == buf) {
3232 /*
3233 * We are at the start of the buffer, and there
3234 * is more file to read backwards. Which means
3235 * we are in the middle of a line. Note that we
3236 * may get here even if *bp was a newline; that
3237 * just means we are at the exact end of the
3238 * previous line, rather than some spot in the
3239 * middle.
3240 *
3241 * Save away what we have to be combined with
3242 * the data from the next read.
3243 */
3244 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3245 break;
3246 }
3247 }
3248
3249 }
3250 if (!ret && sb.len)
3251 die("BUG: reverse reflog parser had leftover data");
3252
3253 fclose(logfp);
3254 strbuf_release(&sb);
3255 return ret;
3256}
3257
e3688bd6
DT
3258static int files_for_each_reflog_ent(struct ref_store *ref_store,
3259 const char *refname,
3260 each_reflog_ent_fn fn, void *cb_data)
7bd9bcf3
MH
3261{
3262 FILE *logfp;
3263 struct strbuf sb = STRBUF_INIT;
3264 int ret = 0;
3265
e3688bd6
DT
3266 /* Check validity (but we don't need the result): */
3267 files_downcast(ref_store, 0, "for_each_reflog_ent");
3268
7bd9bcf3
MH
3269 logfp = fopen(git_path("logs/%s", refname), "r");
3270 if (!logfp)
3271 return -1;
3272
3273 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3274 ret = show_one_reflog_ent(&sb, fn, cb_data);
3275 fclose(logfp);
3276 strbuf_release(&sb);
3277 return ret;
3278}
7bd9bcf3 3279
2880d16f
MH
3280struct files_reflog_iterator {
3281 struct ref_iterator base;
7bd9bcf3 3282
2880d16f
MH
3283 struct dir_iterator *dir_iterator;
3284 struct object_id oid;
3285};
7bd9bcf3 3286
2880d16f
MH
3287static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
3288{
3289 struct files_reflog_iterator *iter =
3290 (struct files_reflog_iterator *)ref_iterator;
3291 struct dir_iterator *diter = iter->dir_iterator;
3292 int ok;
3293
3294 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
3295 int flags;
3296
3297 if (!S_ISREG(diter->st.st_mode))
7bd9bcf3 3298 continue;
2880d16f
MH
3299 if (diter->basename[0] == '.')
3300 continue;
3301 if (ends_with(diter->basename, ".lock"))
7bd9bcf3 3302 continue;
7bd9bcf3 3303
2880d16f
MH
3304 if (read_ref_full(diter->relative_path, 0,
3305 iter->oid.hash, &flags)) {
3306 error("bad ref for %s", diter->path.buf);
3307 continue;
7bd9bcf3 3308 }
2880d16f
MH
3309
3310 iter->base.refname = diter->relative_path;
3311 iter->base.oid = &iter->oid;
3312 iter->base.flags = flags;
3313 return ITER_OK;
7bd9bcf3 3314 }
2880d16f
MH
3315
3316 iter->dir_iterator = NULL;
3317 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
3318 ok = ITER_ERROR;
3319 return ok;
3320}
3321
3322static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
3323 struct object_id *peeled)
3324{
3325 die("BUG: ref_iterator_peel() called for reflog_iterator");
3326}
3327
3328static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
3329{
3330 struct files_reflog_iterator *iter =
3331 (struct files_reflog_iterator *)ref_iterator;
3332 int ok = ITER_DONE;
3333
3334 if (iter->dir_iterator)
3335 ok = dir_iterator_abort(iter->dir_iterator);
3336
3337 base_ref_iterator_free(ref_iterator);
3338 return ok;
3339}
3340
3341static struct ref_iterator_vtable files_reflog_iterator_vtable = {
3342 files_reflog_iterator_advance,
3343 files_reflog_iterator_peel,
3344 files_reflog_iterator_abort
3345};
3346
e3688bd6 3347static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2880d16f
MH
3348{
3349 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
3350 struct ref_iterator *ref_iterator = &iter->base;
3351
e3688bd6
DT
3352 /* Check validity (but we don't need the result): */
3353 files_downcast(ref_store, 0, "reflog_iterator_begin");
3354
2880d16f
MH
3355 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
3356 iter->dir_iterator = dir_iterator_begin(git_path("logs"));
3357 return ref_iterator;
7bd9bcf3
MH
3358}
3359
7bd9bcf3
MH
3360static int ref_update_reject_duplicates(struct string_list *refnames,
3361 struct strbuf *err)
3362{
3363 int i, n = refnames->nr;
3364
3365 assert(err);
3366
3367 for (i = 1; i < n; i++)
3368 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3369 strbuf_addf(err,
0568c8e9 3370 "multiple updates for ref '%s' not allowed.",
7bd9bcf3
MH
3371 refnames->items[i].string);
3372 return 1;
3373 }
3374 return 0;
3375}
3376
165056b2 3377/*
92b1551b
MH
3378 * If update is a direct update of head_ref (the reference pointed to
3379 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
3380 */
3381static int split_head_update(struct ref_update *update,
3382 struct ref_transaction *transaction,
3383 const char *head_ref,
3384 struct string_list *affected_refnames,
3385 struct strbuf *err)
3386{
3387 struct string_list_item *item;
3388 struct ref_update *new_update;
3389
3390 if ((update->flags & REF_LOG_ONLY) ||
3391 (update->flags & REF_ISPRUNING) ||
3392 (update->flags & REF_UPDATE_VIA_HEAD))
3393 return 0;
3394
3395 if (strcmp(update->refname, head_ref))
3396 return 0;
3397
3398 /*
3399 * First make sure that HEAD is not already in the
3400 * transaction. This insertion is O(N) in the transaction
3401 * size, but it happens at most once per transaction.
3402 */
3403 item = string_list_insert(affected_refnames, "HEAD");
3404 if (item->util) {
3405 /* An entry already existed */
3406 strbuf_addf(err,
3407 "multiple updates for 'HEAD' (including one "
3408 "via its referent '%s') are not allowed",
3409 update->refname);
3410 return TRANSACTION_NAME_CONFLICT;
3411 }
3412
3413 new_update = ref_transaction_add_update(
3414 transaction, "HEAD",
3415 update->flags | REF_LOG_ONLY | REF_NODEREF,
3416 update->new_sha1, update->old_sha1,
3417 update->msg);
3418
3419 item->util = new_update;
3420
3421 return 0;
3422}
3423
3424/*
3425 * update is for a symref that points at referent and doesn't have
3426 * REF_NODEREF set. Split it into two updates:
3427 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
3428 * - A new, separate update for the referent reference
3429 * Note that the new update will itself be subject to splitting when
3430 * the iteration gets to it.
3431 */
fcc42ea0
MH
3432static int split_symref_update(struct files_ref_store *refs,
3433 struct ref_update *update,
92b1551b
MH
3434 const char *referent,
3435 struct ref_transaction *transaction,
3436 struct string_list *affected_refnames,
3437 struct strbuf *err)
3438{
3439 struct string_list_item *item;
3440 struct ref_update *new_update;
3441 unsigned int new_flags;
3442
3443 /*
3444 * First make sure that referent is not already in the
3445 * transaction. This insertion is O(N) in the transaction
3446 * size, but it happens at most once per symref in a
3447 * transaction.
3448 */
3449 item = string_list_insert(affected_refnames, referent);
3450 if (item->util) {
3451 /* An entry already existed */
3452 strbuf_addf(err,
3453 "multiple updates for '%s' (including one "
3454 "via symref '%s') are not allowed",
3455 referent, update->refname);
3456 return TRANSACTION_NAME_CONFLICT;
3457 }
3458
3459 new_flags = update->flags;
3460 if (!strcmp(update->refname, "HEAD")) {
3461 /*
3462 * Record that the new update came via HEAD, so that
3463 * when we process it, split_head_update() doesn't try
3464 * to add another reflog update for HEAD. Note that
3465 * this bit will be propagated if the new_update
3466 * itself needs to be split.
3467 */
3468 new_flags |= REF_UPDATE_VIA_HEAD;
3469 }
3470
3471 new_update = ref_transaction_add_update(
3472 transaction, referent, new_flags,
3473 update->new_sha1, update->old_sha1,
3474 update->msg);
3475
6e30b2f6
MH
3476 new_update->parent_update = update;
3477
3478 /*
3479 * Change the symbolic ref update to log only. Also, it
3480 * doesn't need to check its old SHA-1 value, as that will be
3481 * done when new_update is processed.
3482 */
92b1551b 3483 update->flags |= REF_LOG_ONLY | REF_NODEREF;
6e30b2f6 3484 update->flags &= ~REF_HAVE_OLD;
92b1551b
MH
3485
3486 item->util = new_update;
3487
3488 return 0;
3489}
3490
6e30b2f6
MH
3491/*
3492 * Return the refname under which update was originally requested.
3493 */
3494static const char *original_update_refname(struct ref_update *update)
3495{
3496 while (update->parent_update)
3497 update = update->parent_update;
3498
3499 return update->refname;
3500}
3501
e3f51039
MH
3502/*
3503 * Check whether the REF_HAVE_OLD and old_oid values stored in update
3504 * are consistent with oid, which is the reference's current value. If
3505 * everything is OK, return 0; otherwise, write an error message to
3506 * err and return -1.
3507 */
3508static int check_old_oid(struct ref_update *update, struct object_id *oid,
3509 struct strbuf *err)
3510{
3511 if (!(update->flags & REF_HAVE_OLD) ||
3512 !hashcmp(oid->hash, update->old_sha1))
3513 return 0;
3514
3515 if (is_null_sha1(update->old_sha1))
3516 strbuf_addf(err, "cannot lock ref '%s': "
3517 "reference already exists",
3518 original_update_refname(update));
3519 else if (is_null_oid(oid))
3520 strbuf_addf(err, "cannot lock ref '%s': "
3521 "reference is missing but expected %s",
3522 original_update_refname(update),
3523 sha1_to_hex(update->old_sha1));
3524 else
3525 strbuf_addf(err, "cannot lock ref '%s': "
3526 "is at %s but expected %s",
3527 original_update_refname(update),
3528 oid_to_hex(oid),
3529 sha1_to_hex(update->old_sha1));
3530
3531 return -1;
3532}
3533
92b1551b
MH
3534/*
3535 * Prepare for carrying out update:
3536 * - Lock the reference referred to by update.
3537 * - Read the reference under lock.
3538 * - Check that its old SHA-1 value (if specified) is correct, and in
3539 * any case record it in update->lock->old_oid for later use when
3540 * writing the reflog.
3541 * - If it is a symref update without REF_NODEREF, split it up into a
3542 * REF_LOG_ONLY update of the symref and add a separate update for
3543 * the referent to transaction.
3544 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
3545 * update of HEAD.
165056b2 3546 */
b3bbbc5c
MH
3547static int lock_ref_for_update(struct files_ref_store *refs,
3548 struct ref_update *update,
165056b2 3549 struct ref_transaction *transaction,
92b1551b 3550 const char *head_ref,
165056b2
MH
3551 struct string_list *affected_refnames,
3552 struct strbuf *err)
3553{
92b1551b
MH
3554 struct strbuf referent = STRBUF_INIT;
3555 int mustexist = (update->flags & REF_HAVE_OLD) &&
3556 !is_null_sha1(update->old_sha1);
165056b2 3557 int ret;
92b1551b 3558 struct ref_lock *lock;
165056b2 3559
32c597e7 3560 files_assert_main_repository(refs, "lock_ref_for_update");
b3bbbc5c 3561
92b1551b 3562 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
165056b2 3563 update->flags |= REF_DELETING;
92b1551b
MH
3564
3565 if (head_ref) {
3566 ret = split_head_update(update, transaction, head_ref,
3567 affected_refnames, err);
3568 if (ret)
3569 return ret;
3570 }
3571
f7b0a987 3572 ret = lock_raw_ref(refs, update->refname, mustexist,
92b1551b 3573 affected_refnames, NULL,
7d618264 3574 &lock, &referent,
92b1551b 3575 &update->type, err);
92b1551b 3576 if (ret) {
165056b2
MH
3577 char *reason;
3578
165056b2
MH
3579 reason = strbuf_detach(err, NULL);
3580 strbuf_addf(err, "cannot lock ref '%s': %s",
e3f51039 3581 original_update_refname(update), reason);
165056b2
MH
3582 free(reason);
3583 return ret;
3584 }
92b1551b 3585
7d618264 3586 update->backend_data = lock;
92b1551b 3587
8169d0d0 3588 if (update->type & REF_ISSYMREF) {
6e30b2f6
MH
3589 if (update->flags & REF_NODEREF) {
3590 /*
3591 * We won't be reading the referent as part of
3592 * the transaction, so we have to read it here
3593 * to record and possibly check old_sha1:
3594 */
841caad9 3595 if (read_ref_full(referent.buf, 0,
6e30b2f6
MH
3596 lock->old_oid.hash, NULL)) {
3597 if (update->flags & REF_HAVE_OLD) {
3598 strbuf_addf(err, "cannot lock ref '%s': "
e3f51039
MH
3599 "error reading reference",
3600 original_update_refname(update));
3601 return -1;
6e30b2f6 3602 }
e3f51039 3603 } else if (check_old_oid(update, &lock->old_oid, err)) {
8169d0d0 3604 return TRANSACTION_GENERIC_ERROR;
8169d0d0 3605 }
6e30b2f6
MH
3606 } else {
3607 /*
3608 * Create a new update for the reference this
3609 * symref is pointing at. Also, we will record
3610 * and verify old_sha1 for this update as part
3611 * of processing the split-off update, so we
3612 * don't have to do it here.
3613 */
fcc42ea0
MH
3614 ret = split_symref_update(refs, update,
3615 referent.buf, transaction,
92b1551b
MH
3616 affected_refnames, err);
3617 if (ret)
3618 return ret;
3619 }
6e30b2f6
MH
3620 } else {
3621 struct ref_update *parent_update;
8169d0d0 3622
e3f51039
MH
3623 if (check_old_oid(update, &lock->old_oid, err))
3624 return TRANSACTION_GENERIC_ERROR;
3625
6e30b2f6
MH
3626 /*
3627 * If this update is happening indirectly because of a
3628 * symref update, record the old SHA-1 in the parent
3629 * update:
3630 */
3631 for (parent_update = update->parent_update;
3632 parent_update;
3633 parent_update = parent_update->parent_update) {
7d618264
DT
3634 struct ref_lock *parent_lock = parent_update->backend_data;
3635 oidcpy(&parent_lock->old_oid, &lock->old_oid);
6e30b2f6 3636 }
92b1551b
MH
3637 }
3638
165056b2
MH
3639 if ((update->flags & REF_HAVE_NEW) &&
3640 !(update->flags & REF_DELETING) &&
3641 !(update->flags & REF_LOG_ONLY)) {
92b1551b
MH
3642 if (!(update->type & REF_ISSYMREF) &&
3643 !hashcmp(lock->old_oid.hash, update->new_sha1)) {
165056b2
MH
3644 /*
3645 * The reference already has the desired
3646 * value, so we don't need to write it.
3647 */
92b1551b 3648 } else if (write_ref_to_lockfile(lock, update->new_sha1,
165056b2
MH
3649 err)) {
3650 char *write_err = strbuf_detach(err, NULL);
3651
3652 /*
3653 * The lock was freed upon failure of
3654 * write_ref_to_lockfile():
3655 */
7d618264 3656 update->backend_data = NULL;
165056b2 3657 strbuf_addf(err,
e3f51039 3658 "cannot update ref '%s': %s",
165056b2
MH
3659 update->refname, write_err);
3660 free(write_err);
3661 return TRANSACTION_GENERIC_ERROR;
3662 } else {
3663 update->flags |= REF_NEEDS_COMMIT;
3664 }
3665 }
3666 if (!(update->flags & REF_NEEDS_COMMIT)) {
3667 /*
3668 * We didn't call write_ref_to_lockfile(), so
3669 * the lockfile is still open. Close it to
3670 * free up the file descriptor:
3671 */
92b1551b 3672 if (close_ref(lock)) {
165056b2
MH
3673 strbuf_addf(err, "couldn't close '%s.lock'",
3674 update->refname);
3675 return TRANSACTION_GENERIC_ERROR;
3676 }
3677 }
3678 return 0;
3679}
3680
127b42a1
RS
3681static int files_transaction_commit(struct ref_store *ref_store,
3682 struct ref_transaction *transaction,
3683 struct strbuf *err)
7bd9bcf3 3684{
00eebe35 3685 struct files_ref_store *refs =
127b42a1 3686 files_downcast(ref_store, 0, "ref_transaction_commit");
7bd9bcf3 3687 int ret = 0, i;
7bd9bcf3
MH
3688 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3689 struct string_list_item *ref_to_delete;
3690 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
92b1551b
MH
3691 char *head_ref = NULL;
3692 int head_type;
3693 struct object_id head_oid;
7bd9bcf3
MH
3694
3695 assert(err);
3696
3697 if (transaction->state != REF_TRANSACTION_OPEN)
3698 die("BUG: commit called for transaction that is not open");
3699
efe47281 3700 if (!transaction->nr) {
7bd9bcf3
MH
3701 transaction->state = REF_TRANSACTION_CLOSED;
3702 return 0;
3703 }
3704
92b1551b
MH
3705 /*
3706 * Fail if a refname appears more than once in the
3707 * transaction. (If we end up splitting up any updates using
3708 * split_symref_update() or split_head_update(), those
3709 * functions will check that the new updates don't have the
3710 * same refname as any existing ones.)
3711 */
3712 for (i = 0; i < transaction->nr; i++) {
3713 struct ref_update *update = transaction->updates[i];
3714 struct string_list_item *item =
3715 string_list_append(&affected_refnames, update->refname);
3716