refs: make verify_refname_available() virtual
[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);
168
169static struct ref_dir *get_ref_dir(struct ref_entry *entry)
170{
171 struct ref_dir *dir;
172 assert(entry->flag & REF_DIR);
173 dir = &entry->u.subdir;
174 if (entry->flag & REF_INCOMPLETE) {
175 read_loose_refs(entry->name, dir);
176
177 /*
178 * Manually add refs/bisect, which, being
179 * per-worktree, might not appear in the directory
180 * listing for refs/ in the main repo.
181 */
182 if (!strcmp(entry->name, "refs/")) {
183 int pos = search_ref_dir(dir, "refs/bisect/", 12);
184 if (pos < 0) {
185 struct ref_entry *child_entry;
65a0a8e5 186 child_entry = create_dir_entry(dir->ref_store,
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187 "refs/bisect/",
188 12, 1);
189 add_entry_to_dir(dir, child_entry);
190 read_loose_refs("refs/bisect",
191 &child_entry->u.subdir);
192 }
193 }
194 entry->flag &= ~REF_INCOMPLETE;
195 }
196 return dir;
197}
198
199static struct ref_entry *create_ref_entry(const char *refname,
200 const unsigned char *sha1, int flag,
201 int check_name)
202{
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203 struct ref_entry *ref;
204
205 if (check_name &&
206 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
207 die("Reference has invalid format: '%s'", refname);
96ffc06f 208 FLEX_ALLOC_STR(ref, name, refname);
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209 hashcpy(ref->u.value.oid.hash, sha1);
210 oidclr(&ref->u.value.peeled);
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211 ref->flag = flag;
212 return ref;
213}
214
215static void clear_ref_dir(struct ref_dir *dir);
216
217static void free_ref_entry(struct ref_entry *entry)
218{
219 if (entry->flag & REF_DIR) {
220 /*
221 * Do not use get_ref_dir() here, as that might
222 * trigger the reading of loose refs.
223 */
224 clear_ref_dir(&entry->u.subdir);
225 }
226 free(entry);
227}
228
229/*
230 * Add a ref_entry to the end of dir (unsorted). Entry is always
231 * stored directly in dir; no recursion into subdirectories is
232 * done.
233 */
234static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
235{
236 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
237 dir->entries[dir->nr++] = entry;
238 /* optimize for the case that entries are added in order */
239 if (dir->nr == 1 ||
240 (dir->nr == dir->sorted + 1 &&
241 strcmp(dir->entries[dir->nr - 2]->name,
242 dir->entries[dir->nr - 1]->name) < 0))
243 dir->sorted = dir->nr;
244}
245
246/*
247 * Clear and free all entries in dir, recursively.
248 */
249static void clear_ref_dir(struct ref_dir *dir)
250{
251 int i;
252 for (i = 0; i < dir->nr; i++)
253 free_ref_entry(dir->entries[i]);
254 free(dir->entries);
255 dir->sorted = dir->nr = dir->alloc = 0;
256 dir->entries = NULL;
257}
258
259/*
260 * Create a struct ref_entry object for the specified dirname.
261 * dirname is the name of the directory with a trailing slash (e.g.,
262 * "refs/heads/") or "" for the top-level directory.
263 */
65a0a8e5 264static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
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265 const char *dirname, size_t len,
266 int incomplete)
267{
268 struct ref_entry *direntry;
96ffc06f 269 FLEX_ALLOC_MEM(direntry, name, dirname, len);
65a0a8e5 270 direntry->u.subdir.ref_store = ref_store;
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271 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
272 return direntry;
273}
274
275static int ref_entry_cmp(const void *a, const void *b)
276{
277 struct ref_entry *one = *(struct ref_entry **)a;
278 struct ref_entry *two = *(struct ref_entry **)b;
279 return strcmp(one->name, two->name);
280}
281
282static void sort_ref_dir(struct ref_dir *dir);
283
284struct string_slice {
285 size_t len;
286 const char *str;
287};
288
289static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
290{
291 const struct string_slice *key = key_;
292 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
293 int cmp = strncmp(key->str, ent->name, key->len);
294 if (cmp)
295 return cmp;
296 return '\0' - (unsigned char)ent->name[key->len];
297}
298
299/*
300 * Return the index of the entry with the given refname from the
301 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
302 * no such entry is found. dir must already be complete.
303 */
304static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
305{
306 struct ref_entry **r;
307 struct string_slice key;
308
309 if (refname == NULL || !dir->nr)
310 return -1;
311
312 sort_ref_dir(dir);
313 key.len = len;
314 key.str = refname;
315 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
316 ref_entry_cmp_sslice);
317
318 if (r == NULL)
319 return -1;
320
321 return r - dir->entries;
322}
323
324/*
325 * Search for a directory entry directly within dir (without
326 * recursing). Sort dir if necessary. subdirname must be a directory
327 * name (i.e., end in '/'). If mkdir is set, then create the
328 * directory if it is missing; otherwise, return NULL if the desired
329 * directory cannot be found. dir must already be complete.
330 */
331static struct ref_dir *search_for_subdir(struct ref_dir *dir,
332 const char *subdirname, size_t len,
333 int mkdir)
334{
335 int entry_index = search_ref_dir(dir, subdirname, len);
336 struct ref_entry *entry;
337 if (entry_index == -1) {
338 if (!mkdir)
339 return NULL;
340 /*
341 * Since dir is complete, the absence of a subdir
342 * means that the subdir really doesn't exist;
343 * therefore, create an empty record for it but mark
344 * the record complete.
345 */
65a0a8e5 346 entry = create_dir_entry(dir->ref_store, subdirname, len, 0);
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347 add_entry_to_dir(dir, entry);
348 } else {
349 entry = dir->entries[entry_index];
350 }
351 return get_ref_dir(entry);
352}
353
354/*
355 * If refname is a reference name, find the ref_dir within the dir
356 * tree that should hold refname. If refname is a directory name
357 * (i.e., ends in '/'), then return that ref_dir itself. dir must
358 * represent the top-level directory and must already be complete.
359 * Sort ref_dirs and recurse into subdirectories as necessary. If
360 * mkdir is set, then create any missing directories; otherwise,
361 * return NULL if the desired directory cannot be found.
362 */
363static struct ref_dir *find_containing_dir(struct ref_dir *dir,
364 const char *refname, int mkdir)
365{
366 const char *slash;
367 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
368 size_t dirnamelen = slash - refname + 1;
369 struct ref_dir *subdir;
370 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
371 if (!subdir) {
372 dir = NULL;
373 break;
374 }
375 dir = subdir;
376 }
377
378 return dir;
379}
380
381/*
382 * Find the value entry with the given name in dir, sorting ref_dirs
383 * and recursing into subdirectories as necessary. If the name is not
384 * found or it corresponds to a directory entry, return NULL.
385 */
386static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
387{
388 int entry_index;
389 struct ref_entry *entry;
390 dir = find_containing_dir(dir, refname, 0);
391 if (!dir)
392 return NULL;
393 entry_index = search_ref_dir(dir, refname, strlen(refname));
394 if (entry_index == -1)
395 return NULL;
396 entry = dir->entries[entry_index];
397 return (entry->flag & REF_DIR) ? NULL : entry;
398}
399
400/*
401 * Remove the entry with the given name from dir, recursing into
402 * subdirectories as necessary. If refname is the name of a directory
403 * (i.e., ends with '/'), then remove the directory and its contents.
404 * If the removal was successful, return the number of entries
405 * remaining in the directory entry that contained the deleted entry.
406 * If the name was not found, return -1. Please note that this
407 * function only deletes the entry from the cache; it does not delete
408 * it from the filesystem or ensure that other cache entries (which
409 * might be symbolic references to the removed entry) are updated.
410 * Nor does it remove any containing dir entries that might be made
411 * empty by the removal. dir must represent the top-level directory
412 * and must already be complete.
413 */
414static int remove_entry(struct ref_dir *dir, const char *refname)
415{
416 int refname_len = strlen(refname);
417 int entry_index;
418 struct ref_entry *entry;
419 int is_dir = refname[refname_len - 1] == '/';
420 if (is_dir) {
421 /*
422 * refname represents a reference directory. Remove
423 * the trailing slash; otherwise we will get the
424 * directory *representing* refname rather than the
425 * one *containing* it.
426 */
427 char *dirname = xmemdupz(refname, refname_len - 1);
428 dir = find_containing_dir(dir, dirname, 0);
429 free(dirname);
430 } else {
431 dir = find_containing_dir(dir, refname, 0);
432 }
433 if (!dir)
434 return -1;
435 entry_index = search_ref_dir(dir, refname, refname_len);
436 if (entry_index == -1)
437 return -1;
438 entry = dir->entries[entry_index];
439
440 memmove(&dir->entries[entry_index],
441 &dir->entries[entry_index + 1],
442 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
443 );
444 dir->nr--;
445 if (dir->sorted > entry_index)
446 dir->sorted--;
447 free_ref_entry(entry);
448 return dir->nr;
449}
450
451/*
452 * Add a ref_entry to the ref_dir (unsorted), recursing into
453 * subdirectories as necessary. dir must represent the top-level
454 * directory. Return 0 on success.
455 */
456static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
457{
458 dir = find_containing_dir(dir, ref->name, 1);
459 if (!dir)
460 return -1;
461 add_entry_to_dir(dir, ref);
462 return 0;
463}
464
465/*
466 * Emit a warning and return true iff ref1 and ref2 have the same name
467 * and the same sha1. Die if they have the same name but different
468 * sha1s.
469 */
470static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
471{
472 if (strcmp(ref1->name, ref2->name))
473 return 0;
474
475 /* Duplicate name; make sure that they don't conflict: */
476
477 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
478 /* This is impossible by construction */
479 die("Reference directory conflict: %s", ref1->name);
480
481 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
482 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
483
484 warning("Duplicated ref: %s", ref1->name);
485 return 1;
486}
487
488/*
489 * Sort the entries in dir non-recursively (if they are not already
490 * sorted) and remove any duplicate entries.
491 */
492static void sort_ref_dir(struct ref_dir *dir)
493{
494 int i, j;
495 struct ref_entry *last = NULL;
496
497 /*
498 * This check also prevents passing a zero-length array to qsort(),
499 * which is a problem on some platforms.
500 */
501 if (dir->sorted == dir->nr)
502 return;
503
504 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
505
506 /* Remove any duplicates: */
507 for (i = 0, j = 0; j < dir->nr; j++) {
508 struct ref_entry *entry = dir->entries[j];
509 if (last && is_dup_ref(last, entry))
510 free_ref_entry(entry);
511 else
512 last = dir->entries[i++] = entry;
513 }
514 dir->sorted = dir->nr = i;
515}
516
7bd9bcf3 517/*
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518 * Return true if refname, which has the specified oid and flags, can
519 * be resolved to an object in the database. If the referred-to object
520 * does not exist, emit a warning and return false.
7bd9bcf3 521 */
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522static int ref_resolves_to_object(const char *refname,
523 const struct object_id *oid,
524 unsigned int flags)
7bd9bcf3 525{
a8739244 526 if (flags & REF_ISBROKEN)
7bd9bcf3 527 return 0;
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528 if (!has_sha1_file(oid->hash)) {
529 error("%s does not point to a valid object!", refname);
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530 return 0;
531 }
532 return 1;
533}
534
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535/*
536 * Return true if the reference described by entry can be resolved to
537 * an object in the database; otherwise, emit a warning and return
538 * false.
539 */
540static int entry_resolves_to_object(struct ref_entry *entry)
541{
542 return ref_resolves_to_object(entry->name,
543 &entry->u.value.oid, entry->flag);
544}
545
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546typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
547
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548/*
549 * Call fn for each reference in dir that has index in the range
550 * offset <= index < dir->nr. Recurse into subdirectories that are in
551 * that index range, sorting them before iterating. This function
552 * does not sort dir itself; it should be sorted beforehand. fn is
553 * called for all references, including broken ones.
554 */
555static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
556 each_ref_entry_fn fn, void *cb_data)
557{
558 int i;
559 assert(dir->sorted == dir->nr);
560 for (i = offset; i < dir->nr; i++) {
561 struct ref_entry *entry = dir->entries[i];
562 int retval;
563 if (entry->flag & REF_DIR) {
564 struct ref_dir *subdir = get_ref_dir(entry);
565 sort_ref_dir(subdir);
566 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
567 } else {
568 retval = fn(entry, cb_data);
569 }
570 if (retval)
571 return retval;
572 }
573 return 0;
574}
575
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576/*
577 * Load all of the refs from the dir into our in-memory cache. The hard work
578 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
579 * through all of the sub-directories. We do not even need to care about
580 * sorting, as traversal order does not matter to us.
581 */
582static void prime_ref_dir(struct ref_dir *dir)
583{
584 int i;
585 for (i = 0; i < dir->nr; i++) {
586 struct ref_entry *entry = dir->entries[i];
587 if (entry->flag & REF_DIR)
588 prime_ref_dir(get_ref_dir(entry));
589 }
590}
591
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592/*
593 * A level in the reference hierarchy that is currently being iterated
594 * through.
595 */
596struct cache_ref_iterator_level {
597 /*
598 * The ref_dir being iterated over at this level. The ref_dir
599 * is sorted before being stored here.
600 */
601 struct ref_dir *dir;
602
603 /*
604 * The index of the current entry within dir (which might
605 * itself be a directory). If index == -1, then the iteration
606 * hasn't yet begun. If index == dir->nr, then the iteration
607 * through this level is over.
608 */
609 int index;
610};
611
612/*
613 * Represent an iteration through a ref_dir in the memory cache. The
614 * iteration recurses through subdirectories.
615 */
616struct cache_ref_iterator {
617 struct ref_iterator base;
618
619 /*
620 * The number of levels currently on the stack. This is always
621 * at least 1, because when it becomes zero the iteration is
622 * ended and this struct is freed.
623 */
624 size_t levels_nr;
625
626 /* The number of levels that have been allocated on the stack */
627 size_t levels_alloc;
628
629 /*
630 * A stack of levels. levels[0] is the uppermost level that is
631 * being iterated over in this iteration. (This is not
632 * necessary the top level in the references hierarchy. If we
633 * are iterating through a subtree, then levels[0] will hold
634 * the ref_dir for that subtree, and subsequent levels will go
635 * on from there.)
636 */
637 struct cache_ref_iterator_level *levels;
638};
639
640static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
641{
642 struct cache_ref_iterator *iter =
643 (struct cache_ref_iterator *)ref_iterator;
644
645 while (1) {
646 struct cache_ref_iterator_level *level =
647 &iter->levels[iter->levels_nr - 1];
648 struct ref_dir *dir = level->dir;
649 struct ref_entry *entry;
650
651 if (level->index == -1)
652 sort_ref_dir(dir);
653
654 if (++level->index == level->dir->nr) {
655 /* This level is exhausted; pop up a level */
656 if (--iter->levels_nr == 0)
657 return ref_iterator_abort(ref_iterator);
658
659 continue;
660 }
661
662 entry = dir->entries[level->index];
663
664 if (entry->flag & REF_DIR) {
665 /* push down a level */
666 ALLOC_GROW(iter->levels, iter->levels_nr + 1,
667 iter->levels_alloc);
668
669 level = &iter->levels[iter->levels_nr++];
670 level->dir = get_ref_dir(entry);
671 level->index = -1;
672 } else {
673 iter->base.refname = entry->name;
674 iter->base.oid = &entry->u.value.oid;
675 iter->base.flags = entry->flag;
676 return ITER_OK;
677 }
678 }
679}
680
681static enum peel_status peel_entry(struct ref_entry *entry, int repeel);
682
683static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
684 struct object_id *peeled)
685{
686 struct cache_ref_iterator *iter =
687 (struct cache_ref_iterator *)ref_iterator;
688 struct cache_ref_iterator_level *level;
689 struct ref_entry *entry;
690
691 level = &iter->levels[iter->levels_nr - 1];
692
693 if (level->index == -1)
694 die("BUG: peel called before advance for cache iterator");
695
696 entry = level->dir->entries[level->index];
697
698 if (peel_entry(entry, 0))
699 return -1;
700 hashcpy(peeled->hash, entry->u.value.peeled.hash);
701 return 0;
702}
703
704static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator)
705{
706 struct cache_ref_iterator *iter =
707 (struct cache_ref_iterator *)ref_iterator;
708
709 free(iter->levels);
710 base_ref_iterator_free(ref_iterator);
711 return ITER_DONE;
712}
713
714static struct ref_iterator_vtable cache_ref_iterator_vtable = {
715 cache_ref_iterator_advance,
716 cache_ref_iterator_peel,
717 cache_ref_iterator_abort
718};
719
720static struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir)
721{
722 struct cache_ref_iterator *iter;
723 struct ref_iterator *ref_iterator;
724 struct cache_ref_iterator_level *level;
725
726 iter = xcalloc(1, sizeof(*iter));
727 ref_iterator = &iter->base;
728 base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable);
729 ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
730
731 iter->levels_nr = 1;
732 level = &iter->levels[0];
733 level->index = -1;
734 level->dir = dir;
735
736 return ref_iterator;
737}
738
7bd9bcf3
MH
739struct nonmatching_ref_data {
740 const struct string_list *skip;
741 const char *conflicting_refname;
742};
743
744static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
745{
746 struct nonmatching_ref_data *data = vdata;
747
748 if (data->skip && string_list_has_string(data->skip, entry->name))
749 return 0;
750
751 data->conflicting_refname = entry->name;
752 return 1;
753}
754
755/*
756 * Return 0 if a reference named refname could be created without
757 * conflicting with the name of an existing reference in dir.
758 * See verify_refname_available for more information.
759 */
760static int verify_refname_available_dir(const char *refname,
761 const struct string_list *extras,
762 const struct string_list *skip,
763 struct ref_dir *dir,
764 struct strbuf *err)
765{
766 const char *slash;
0845122c 767 const char *extra_refname;
7bd9bcf3
MH
768 int pos;
769 struct strbuf dirname = STRBUF_INIT;
770 int ret = -1;
771
772 /*
773 * For the sake of comments in this function, suppose that
774 * refname is "refs/foo/bar".
775 */
776
777 assert(err);
778
779 strbuf_grow(&dirname, strlen(refname) + 1);
780 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
781 /* Expand dirname to the new prefix, not including the trailing slash: */
782 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
783
784 /*
785 * We are still at a leading dir of the refname (e.g.,
786 * "refs/foo"; if there is a reference with that name,
787 * it is a conflict, *unless* it is in skip.
788 */
789 if (dir) {
790 pos = search_ref_dir(dir, dirname.buf, dirname.len);
791 if (pos >= 0 &&
792 (!skip || !string_list_has_string(skip, dirname.buf))) {
793 /*
794 * We found a reference whose name is
795 * a proper prefix of refname; e.g.,
796 * "refs/foo", and is not in skip.
797 */
798 strbuf_addf(err, "'%s' exists; cannot create '%s'",
799 dirname.buf, refname);
800 goto cleanup;
801 }
802 }
803
804 if (extras && string_list_has_string(extras, dirname.buf) &&
805 (!skip || !string_list_has_string(skip, dirname.buf))) {
806 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
807 refname, dirname.buf);
808 goto cleanup;
809 }
810
811 /*
812 * Otherwise, we can try to continue our search with
813 * the next component. So try to look up the
814 * directory, e.g., "refs/foo/". If we come up empty,
815 * we know there is nothing under this whole prefix,
816 * but even in that case we still have to continue the
817 * search for conflicts with extras.
818 */
819 strbuf_addch(&dirname, '/');
820 if (dir) {
821 pos = search_ref_dir(dir, dirname.buf, dirname.len);
822 if (pos < 0) {
823 /*
824 * There was no directory "refs/foo/",
825 * so there is nothing under this
826 * whole prefix. So there is no need
827 * to continue looking for conflicting
828 * references. But we need to continue
829 * looking for conflicting extras.
830 */
831 dir = NULL;
832 } else {
833 dir = get_ref_dir(dir->entries[pos]);
834 }
835 }
836 }
837
838 /*
839 * We are at the leaf of our refname (e.g., "refs/foo/bar").
840 * There is no point in searching for a reference with that
841 * name, because a refname isn't considered to conflict with
842 * itself. But we still need to check for references whose
843 * names are in the "refs/foo/bar/" namespace, because they
844 * *do* conflict.
845 */
846 strbuf_addstr(&dirname, refname + dirname.len);
847 strbuf_addch(&dirname, '/');
848
849 if (dir) {
850 pos = search_ref_dir(dir, dirname.buf, dirname.len);
851
852 if (pos >= 0) {
853 /*
854 * We found a directory named "$refname/"
855 * (e.g., "refs/foo/bar/"). It is a problem
856 * iff it contains any ref that is not in
857 * "skip".
858 */
859 struct nonmatching_ref_data data;
860
861 data.skip = skip;
862 data.conflicting_refname = NULL;
863 dir = get_ref_dir(dir->entries[pos]);
864 sort_ref_dir(dir);
865 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
866 strbuf_addf(err, "'%s' exists; cannot create '%s'",
867 data.conflicting_refname, refname);
868 goto cleanup;
869 }
870 }
871 }
872
0845122c
DT
873 extra_refname = find_descendant_ref(dirname.buf, extras, skip);
874 if (extra_refname)
875 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
876 refname, extra_refname);
877 else
878 ret = 0;
7bd9bcf3
MH
879
880cleanup:
881 strbuf_release(&dirname);
882 return ret;
883}
884
885struct packed_ref_cache {
886 struct ref_entry *root;
887
888 /*
889 * Count of references to the data structure in this instance,
65a0a8e5
MH
890 * including the pointer from files_ref_store::packed if any.
891 * The data will not be freed as long as the reference count
892 * is nonzero.
7bd9bcf3
MH
893 */
894 unsigned int referrers;
895
896 /*
897 * Iff the packed-refs file associated with this instance is
898 * currently locked for writing, this points at the associated
899 * lock (which is owned by somebody else). The referrer count
900 * is also incremented when the file is locked and decremented
901 * when it is unlocked.
902 */
903 struct lock_file *lock;
904
905 /* The metadata from when this packed-refs cache was read */
906 struct stat_validity validity;
907};
908
909/*
910 * Future: need to be in "struct repository"
911 * when doing a full libification.
912 */
00eebe35
MH
913struct files_ref_store {
914 struct ref_store base;
7bd9bcf3
MH
915 struct ref_entry *loose;
916 struct packed_ref_cache *packed;
00eebe35 917};
7bd9bcf3
MH
918
919/* Lock used for the main packed-refs file: */
920static struct lock_file packlock;
921
922/*
923 * Increment the reference count of *packed_refs.
924 */
925static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
926{
927 packed_refs->referrers++;
928}
929
930/*
931 * Decrease the reference count of *packed_refs. If it goes to zero,
932 * free *packed_refs and return true; otherwise return false.
933 */
934static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
935{
936 if (!--packed_refs->referrers) {
937 free_ref_entry(packed_refs->root);
938 stat_validity_clear(&packed_refs->validity);
939 free(packed_refs);
940 return 1;
941 } else {
942 return 0;
943 }
944}
945
65a0a8e5 946static void clear_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
947{
948 if (refs->packed) {
949 struct packed_ref_cache *packed_refs = refs->packed;
950
951 if (packed_refs->lock)
952 die("internal error: packed-ref cache cleared while locked");
953 refs->packed = NULL;
954 release_packed_ref_cache(packed_refs);
955 }
956}
957
65a0a8e5 958static void clear_loose_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
959{
960 if (refs->loose) {
961 free_ref_entry(refs->loose);
962 refs->loose = NULL;
963 }
964}
965
a2d5156c
JK
966/*
967 * Create a new submodule ref cache and add it to the internal
968 * set of caches.
969 */
00eebe35 970static struct ref_store *files_ref_store_create(const char *submodule)
7bd9bcf3 971{
00eebe35
MH
972 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
973 struct ref_store *ref_store = (struct ref_store *)refs;
974
975 base_ref_store_init(ref_store, &refs_be_files, submodule);
976
977 return ref_store;
7bd9bcf3
MH
978}
979
00eebe35
MH
980/*
981 * Downcast ref_store to files_ref_store. Die if ref_store is not a
982 * files_ref_store. If submodule_allowed is not true, then also die if
983 * files_ref_store is for a submodule (i.e., not for the main
984 * repository). caller is used in any necessary error messages.
985 */
986static struct files_ref_store *files_downcast(
987 struct ref_store *ref_store, int submodule_allowed,
988 const char *caller)
7bd9bcf3 989{
00eebe35
MH
990 if (ref_store->be != &refs_be_files)
991 die("BUG: ref_store is type \"%s\" not \"files\" in %s",
992 ref_store->be->name, caller);
7bd9bcf3 993
00eebe35
MH
994 if (!submodule_allowed)
995 assert_main_repository(ref_store, caller);
7bd9bcf3 996
00eebe35 997 return (struct files_ref_store *)ref_store;
a2d5156c 998}
7bd9bcf3 999
a2d5156c 1000/*
00eebe35
MH
1001 * Return a pointer to the reference store for the specified
1002 * submodule. For the main repository, use submodule==NULL; such a
1003 * call cannot fail. For a submodule, the submodule must exist and be
1004 * a nonbare repository, otherwise return NULL. Verify that the
1005 * reference store is a files_ref_store, and cast it to that type
1006 * before returning it.
a2d5156c 1007 */
00eebe35
MH
1008static struct files_ref_store *get_files_ref_store(const char *submodule,
1009 const char *caller)
a2d5156c 1010{
00eebe35 1011 struct ref_store *refs = get_ref_store(submodule);
2eed2780 1012
00eebe35 1013 return refs ? files_downcast(refs, 1, caller) : NULL;
7bd9bcf3
MH
1014}
1015
1016/* The length of a peeled reference line in packed-refs, including EOL: */
1017#define PEELED_LINE_LENGTH 42
1018
1019/*
1020 * The packed-refs header line that we write out. Perhaps other
1021 * traits will be added later. The trailing space is required.
1022 */
1023static const char PACKED_REFS_HEADER[] =
1024 "# pack-refs with: peeled fully-peeled \n";
1025
1026/*
1027 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1028 * Return a pointer to the refname within the line (null-terminated),
1029 * or NULL if there was a problem.
1030 */
1031static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1032{
1033 const char *ref;
1034
1035 /*
1036 * 42: the answer to everything.
1037 *
1038 * In this case, it happens to be the answer to
1039 * 40 (length of sha1 hex representation)
1040 * +1 (space in between hex and name)
1041 * +1 (newline at the end of the line)
1042 */
1043 if (line->len <= 42)
1044 return NULL;
1045
1046 if (get_sha1_hex(line->buf, sha1) < 0)
1047 return NULL;
1048 if (!isspace(line->buf[40]))
1049 return NULL;
1050
1051 ref = line->buf + 41;
1052 if (isspace(*ref))
1053 return NULL;
1054
1055 if (line->buf[line->len - 1] != '\n')
1056 return NULL;
1057 line->buf[--line->len] = 0;
1058
1059 return ref;
1060}
1061
1062/*
1063 * Read f, which is a packed-refs file, into dir.
1064 *
1065 * A comment line of the form "# pack-refs with: " may contain zero or
1066 * more traits. We interpret the traits as follows:
1067 *
1068 * No traits:
1069 *
1070 * Probably no references are peeled. But if the file contains a
1071 * peeled value for a reference, we will use it.
1072 *
1073 * peeled:
1074 *
1075 * References under "refs/tags/", if they *can* be peeled, *are*
1076 * peeled in this file. References outside of "refs/tags/" are
1077 * probably not peeled even if they could have been, but if we find
1078 * a peeled value for such a reference we will use it.
1079 *
1080 * fully-peeled:
1081 *
1082 * All references in the file that can be peeled are peeled.
1083 * Inversely (and this is more important), any references in the
1084 * file for which no peeled value is recorded is not peelable. This
1085 * trait should typically be written alongside "peeled" for
1086 * compatibility with older clients, but we do not require it
1087 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1088 */
1089static void read_packed_refs(FILE *f, struct ref_dir *dir)
1090{
1091 struct ref_entry *last = NULL;
1092 struct strbuf line = STRBUF_INIT;
1093 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1094
1095 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1096 unsigned char sha1[20];
1097 const char *refname;
1098 const char *traits;
1099
1100 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1101 if (strstr(traits, " fully-peeled "))
1102 peeled = PEELED_FULLY;
1103 else if (strstr(traits, " peeled "))
1104 peeled = PEELED_TAGS;
1105 /* perhaps other traits later as well */
1106 continue;
1107 }
1108
1109 refname = parse_ref_line(&line, sha1);
1110 if (refname) {
1111 int flag = REF_ISPACKED;
1112
1113 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1114 if (!refname_is_safe(refname))
1115 die("packed refname is dangerous: %s", refname);
1116 hashclr(sha1);
1117 flag |= REF_BAD_NAME | REF_ISBROKEN;
1118 }
1119 last = create_ref_entry(refname, sha1, flag, 0);
1120 if (peeled == PEELED_FULLY ||
1121 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1122 last->flag |= REF_KNOWS_PEELED;
1123 add_ref(dir, last);
1124 continue;
1125 }
1126 if (last &&
1127 line.buf[0] == '^' &&
1128 line.len == PEELED_LINE_LENGTH &&
1129 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1130 !get_sha1_hex(line.buf + 1, sha1)) {
1131 hashcpy(last->u.value.peeled.hash, sha1);
1132 /*
1133 * Regardless of what the file header said,
1134 * we definitely know the value of *this*
1135 * reference:
1136 */
1137 last->flag |= REF_KNOWS_PEELED;
1138 }
1139 }
1140
1141 strbuf_release(&line);
1142}
1143
1144/*
65a0a8e5
MH
1145 * Get the packed_ref_cache for the specified files_ref_store,
1146 * creating it if necessary.
7bd9bcf3 1147 */
65a0a8e5 1148static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
1149{
1150 char *packed_refs_file;
1151
00eebe35
MH
1152 if (*refs->base.submodule)
1153 packed_refs_file = git_pathdup_submodule(refs->base.submodule,
1154 "packed-refs");
7bd9bcf3
MH
1155 else
1156 packed_refs_file = git_pathdup("packed-refs");
1157
1158 if (refs->packed &&
1159 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1160 clear_packed_ref_cache(refs);
1161
1162 if (!refs->packed) {
1163 FILE *f;
1164
1165 refs->packed = xcalloc(1, sizeof(*refs->packed));
1166 acquire_packed_ref_cache(refs->packed);
1167 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1168 f = fopen(packed_refs_file, "r");
1169 if (f) {
1170 stat_validity_update(&refs->packed->validity, fileno(f));
1171 read_packed_refs(f, get_ref_dir(refs->packed->root));
1172 fclose(f);
1173 }
1174 }
1175 free(packed_refs_file);
1176 return refs->packed;
1177}
1178
1179static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1180{
1181 return get_ref_dir(packed_ref_cache->root);
1182}
1183
65a0a8e5 1184static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1185{
1186 return get_packed_ref_dir(get_packed_ref_cache(refs));
1187}
1188
1189/*
1190 * Add a reference to the in-memory packed reference cache. This may
1191 * only be called while the packed-refs file is locked (see
1192 * lock_packed_refs()). To actually write the packed-refs file, call
1193 * commit_packed_refs().
1194 */
d99825ab
MH
1195static void add_packed_ref(struct files_ref_store *refs,
1196 const char *refname, const unsigned char *sha1)
7bd9bcf3 1197{
00eebe35 1198 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
1199
1200 if (!packed_ref_cache->lock)
1201 die("internal error: packed refs not locked");
1202 add_ref(get_packed_ref_dir(packed_ref_cache),
1203 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1204}
1205
1206/*
1207 * Read the loose references from the namespace dirname into dir
1208 * (without recursing). dirname must end with '/'. dir must be the
1209 * directory entry corresponding to dirname.
1210 */
1211static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1212{
65a0a8e5 1213 struct files_ref_store *refs = dir->ref_store;
7bd9bcf3
MH
1214 DIR *d;
1215 struct dirent *de;
1216 int dirnamelen = strlen(dirname);
1217 struct strbuf refname;
1218 struct strbuf path = STRBUF_INIT;
1219 size_t path_baselen;
1220
00eebe35
MH
1221 if (*refs->base.submodule)
1222 strbuf_git_path_submodule(&path, refs->base.submodule, "%s", dirname);
7bd9bcf3
MH
1223 else
1224 strbuf_git_path(&path, "%s", dirname);
1225 path_baselen = path.len;
1226
1227 d = opendir(path.buf);
1228 if (!d) {
1229 strbuf_release(&path);
1230 return;
1231 }
1232
1233 strbuf_init(&refname, dirnamelen + 257);
1234 strbuf_add(&refname, dirname, dirnamelen);
1235
1236 while ((de = readdir(d)) != NULL) {
1237 unsigned char sha1[20];
1238 struct stat st;
1239 int flag;
1240
1241 if (de->d_name[0] == '.')
1242 continue;
1243 if (ends_with(de->d_name, ".lock"))
1244 continue;
1245 strbuf_addstr(&refname, de->d_name);
1246 strbuf_addstr(&path, de->d_name);
1247 if (stat(path.buf, &st) < 0) {
1248 ; /* silently ignore */
1249 } else if (S_ISDIR(st.st_mode)) {
1250 strbuf_addch(&refname, '/');
1251 add_entry_to_dir(dir,
1252 create_dir_entry(refs, refname.buf,
1253 refname.len, 1));
1254 } else {
1255 int read_ok;
1256
00eebe35 1257 if (*refs->base.submodule) {
7bd9bcf3
MH
1258 hashclr(sha1);
1259 flag = 0;
00eebe35 1260 read_ok = !resolve_gitlink_ref(refs->base.submodule,
7bd9bcf3
MH
1261 refname.buf, sha1);
1262 } else {
1263 read_ok = !read_ref_full(refname.buf,
1264 RESOLVE_REF_READING,
1265 sha1, &flag);
1266 }
1267
1268 if (!read_ok) {
1269 hashclr(sha1);
1270 flag |= REF_ISBROKEN;
1271 } else if (is_null_sha1(sha1)) {
1272 /*
1273 * It is so astronomically unlikely
1274 * that NULL_SHA1 is the SHA-1 of an
1275 * actual object that we consider its
1276 * appearance in a loose reference
1277 * file to be repo corruption
1278 * (probably due to a software bug).
1279 */
1280 flag |= REF_ISBROKEN;
1281 }
1282
1283 if (check_refname_format(refname.buf,
1284 REFNAME_ALLOW_ONELEVEL)) {
1285 if (!refname_is_safe(refname.buf))
1286 die("loose refname is dangerous: %s", refname.buf);
1287 hashclr(sha1);
1288 flag |= REF_BAD_NAME | REF_ISBROKEN;
1289 }
1290 add_entry_to_dir(dir,
1291 create_ref_entry(refname.buf, sha1, flag, 0));
1292 }
1293 strbuf_setlen(&refname, dirnamelen);
1294 strbuf_setlen(&path, path_baselen);
1295 }
1296 strbuf_release(&refname);
1297 strbuf_release(&path);
1298 closedir(d);
1299}
1300
65a0a8e5 1301static struct ref_dir *get_loose_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1302{
1303 if (!refs->loose) {
1304 /*
1305 * Mark the top-level directory complete because we
1306 * are about to read the only subdirectory that can
1307 * hold references:
1308 */
1309 refs->loose = create_dir_entry(refs, "", 0, 0);
1310 /*
1311 * Create an incomplete entry for "refs/":
1312 */
1313 add_entry_to_dir(get_ref_dir(refs->loose),
1314 create_dir_entry(refs, "refs/", 5, 1));
1315 }
1316 return get_ref_dir(refs->loose);
1317}
1318
7bd9bcf3
MH
1319/*
1320 * Return the ref_entry for the given refname from the packed
1321 * references. If it does not exist, return NULL.
1322 */
f0d21efc
MH
1323static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
1324 const char *refname)
7bd9bcf3 1325{
00eebe35 1326 return find_ref(get_packed_refs(refs), refname);
7bd9bcf3
MH
1327}
1328
1329/*
419c6f4c 1330 * A loose ref file doesn't exist; check for a packed ref.
7bd9bcf3 1331 */
611118d0
MH
1332static int resolve_packed_ref(struct files_ref_store *refs,
1333 const char *refname,
1334 unsigned char *sha1, unsigned int *flags)
7bd9bcf3
MH
1335{
1336 struct ref_entry *entry;
1337
1338 /*
1339 * The loose reference file does not exist; check for a packed
1340 * reference.
1341 */
f0d21efc 1342 entry = get_packed_ref(refs, refname);
7bd9bcf3
MH
1343 if (entry) {
1344 hashcpy(sha1, entry->u.value.oid.hash);
a70a93b7 1345 *flags |= REF_ISPACKED;
7bd9bcf3
MH
1346 return 0;
1347 }
419c6f4c
MH
1348 /* refname is not a packed reference. */
1349 return -1;
7bd9bcf3
MH
1350}
1351
e1e33b72
MH
1352static int files_read_raw_ref(struct ref_store *ref_store,
1353 const char *refname, unsigned char *sha1,
1354 struct strbuf *referent, unsigned int *type)
7bd9bcf3 1355{
4308651c 1356 struct files_ref_store *refs =
34c7ad8f 1357 files_downcast(ref_store, 1, "read_raw_ref");
42a38cf7
MH
1358 struct strbuf sb_contents = STRBUF_INIT;
1359 struct strbuf sb_path = STRBUF_INIT;
7048653a
DT
1360 const char *path;
1361 const char *buf;
1362 struct stat st;
1363 int fd;
42a38cf7
MH
1364 int ret = -1;
1365 int save_errno;
7bd9bcf3 1366
fa96ea1b 1367 *type = 0;
42a38cf7 1368 strbuf_reset(&sb_path);
34c7ad8f
MH
1369
1370 if (*refs->base.submodule)
1371 strbuf_git_path_submodule(&sb_path, refs->base.submodule, "%s", refname);
1372 else
1373 strbuf_git_path(&sb_path, "%s", refname);
1374
42a38cf7 1375 path = sb_path.buf;
7bd9bcf3 1376
7048653a
DT
1377stat_ref:
1378 /*
1379 * We might have to loop back here to avoid a race
1380 * condition: first we lstat() the file, then we try
1381 * to read it as a link or as a file. But if somebody
1382 * changes the type of the file (file <-> directory
1383 * <-> symlink) between the lstat() and reading, then
1384 * we don't want to report that as an error but rather
1385 * try again starting with the lstat().
1386 */
7bd9bcf3 1387
7048653a
DT
1388 if (lstat(path, &st) < 0) {
1389 if (errno != ENOENT)
42a38cf7 1390 goto out;
611118d0 1391 if (resolve_packed_ref(refs, refname, sha1, type)) {
7048653a 1392 errno = ENOENT;
42a38cf7 1393 goto out;
7bd9bcf3 1394 }
42a38cf7
MH
1395 ret = 0;
1396 goto out;
7bd9bcf3 1397 }
7bd9bcf3 1398
7048653a
DT
1399 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1400 if (S_ISLNK(st.st_mode)) {
42a38cf7
MH
1401 strbuf_reset(&sb_contents);
1402 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
7048653a 1403 if (errno == ENOENT || errno == EINVAL)
7bd9bcf3
MH
1404 /* inconsistent with lstat; retry */
1405 goto stat_ref;
1406 else
42a38cf7 1407 goto out;
7bd9bcf3 1408 }
42a38cf7
MH
1409 if (starts_with(sb_contents.buf, "refs/") &&
1410 !check_refname_format(sb_contents.buf, 0)) {
92b38093 1411 strbuf_swap(&sb_contents, referent);
3a0b6b9a 1412 *type |= REF_ISSYMREF;
42a38cf7
MH
1413 ret = 0;
1414 goto out;
7bd9bcf3 1415 }
7048653a 1416 }
7bd9bcf3 1417
7048653a
DT
1418 /* Is it a directory? */
1419 if (S_ISDIR(st.st_mode)) {
e167a567
MH
1420 /*
1421 * Even though there is a directory where the loose
1422 * ref is supposed to be, there could still be a
1423 * packed ref:
1424 */
611118d0 1425 if (resolve_packed_ref(refs, refname, sha1, type)) {
e167a567
MH
1426 errno = EISDIR;
1427 goto out;
1428 }
1429 ret = 0;
42a38cf7 1430 goto out;
7048653a
DT
1431 }
1432
1433 /*
1434 * Anything else, just open it and try to use it as
1435 * a ref
1436 */
1437 fd = open(path, O_RDONLY);
1438 if (fd < 0) {
1439 if (errno == ENOENT)
1440 /* inconsistent with lstat; retry */
1441 goto stat_ref;
1442 else
42a38cf7 1443 goto out;
7048653a 1444 }
42a38cf7
MH
1445 strbuf_reset(&sb_contents);
1446 if (strbuf_read(&sb_contents, fd, 256) < 0) {
7048653a
DT
1447 int save_errno = errno;
1448 close(fd);
1449 errno = save_errno;
42a38cf7 1450 goto out;
7048653a
DT
1451 }
1452 close(fd);
42a38cf7
MH
1453 strbuf_rtrim(&sb_contents);
1454 buf = sb_contents.buf;
7048653a
DT
1455 if (starts_with(buf, "ref:")) {
1456 buf += 4;
7bd9bcf3
MH
1457 while (isspace(*buf))
1458 buf++;
7048653a 1459
92b38093
MH
1460 strbuf_reset(referent);
1461 strbuf_addstr(referent, buf);
3a0b6b9a 1462 *type |= REF_ISSYMREF;
42a38cf7
MH
1463 ret = 0;
1464 goto out;
7bd9bcf3 1465 }
7bd9bcf3 1466
7048653a
DT
1467 /*
1468 * Please note that FETCH_HEAD has additional
1469 * data after the sha.
1470 */
1471 if (get_sha1_hex(buf, sha1) ||
1472 (buf[40] != '\0' && !isspace(buf[40]))) {
3a0b6b9a 1473 *type |= REF_ISBROKEN;
7048653a 1474 errno = EINVAL;
42a38cf7 1475 goto out;
7048653a
DT
1476 }
1477
42a38cf7 1478 ret = 0;
7bd9bcf3 1479
42a38cf7
MH
1480out:
1481 save_errno = errno;
7bd9bcf3
MH
1482 strbuf_release(&sb_path);
1483 strbuf_release(&sb_contents);
42a38cf7 1484 errno = save_errno;
7bd9bcf3
MH
1485 return ret;
1486}
1487
8415d247
MH
1488static void unlock_ref(struct ref_lock *lock)
1489{
1490 /* Do not free lock->lk -- atexit() still looks at them */
1491 if (lock->lk)
1492 rollback_lock_file(lock->lk);
1493 free(lock->ref_name);
8415d247
MH
1494 free(lock);
1495}
1496
92b1551b
MH
1497/*
1498 * Lock refname, without following symrefs, and set *lock_p to point
1499 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
1500 * and type similarly to read_raw_ref().
1501 *
1502 * The caller must verify that refname is a "safe" reference name (in
1503 * the sense of refname_is_safe()) before calling this function.
1504 *
1505 * If the reference doesn't already exist, verify that refname doesn't
1506 * have a D/F conflict with any existing references. extras and skip
1507 * are passed to verify_refname_available_dir() for this check.
1508 *
1509 * If mustexist is not set and the reference is not found or is
1510 * broken, lock the reference anyway but clear sha1.
1511 *
1512 * Return 0 on success. On failure, write an error message to err and
1513 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
1514 *
1515 * Implementation note: This function is basically
1516 *
1517 * lock reference
1518 * read_raw_ref()
1519 *
1520 * but it includes a lot more code to
1521 * - Deal with possible races with other processes
1522 * - Avoid calling verify_refname_available_dir() when it can be
1523 * avoided, namely if we were successfully able to read the ref
1524 * - Generate informative error messages in the case of failure
1525 */
1526static int lock_raw_ref(const char *refname, int mustexist,
1527 const struct string_list *extras,
1528 const struct string_list *skip,
1529 struct ref_lock **lock_p,
1530 struct strbuf *referent,
1531 unsigned int *type,
1532 struct strbuf *err)
1533{
34c7ad8f 1534 struct ref_store *ref_store = get_ref_store(NULL);
00eebe35 1535 struct files_ref_store *refs =
34c7ad8f 1536 files_downcast(ref_store, 0, "lock_raw_ref");
92b1551b
MH
1537 struct ref_lock *lock;
1538 struct strbuf ref_file = STRBUF_INIT;
1539 int attempts_remaining = 3;
1540 int ret = TRANSACTION_GENERIC_ERROR;
1541
1542 assert(err);
1543 *type = 0;
1544
1545 /* First lock the file so it can't change out from under us. */
1546
1547 *lock_p = lock = xcalloc(1, sizeof(*lock));
1548
1549 lock->ref_name = xstrdup(refname);
92b1551b
MH
1550 strbuf_git_path(&ref_file, "%s", refname);
1551
1552retry:
1553 switch (safe_create_leading_directories(ref_file.buf)) {
1554 case SCLD_OK:
1555 break; /* success */
1556 case SCLD_EXISTS:
1557 /*
1558 * Suppose refname is "refs/foo/bar". We just failed
1559 * to create the containing directory, "refs/foo",
1560 * because there was a non-directory in the way. This
1561 * indicates a D/F conflict, probably because of
1562 * another reference such as "refs/foo". There is no
1563 * reason to expect this error to be transitory.
1564 */
1565 if (verify_refname_available(refname, extras, skip, err)) {
1566 if (mustexist) {
1567 /*
1568 * To the user the relevant error is
1569 * that the "mustexist" reference is
1570 * missing:
1571 */
1572 strbuf_reset(err);
1573 strbuf_addf(err, "unable to resolve reference '%s'",
1574 refname);
1575 } else {
1576 /*
1577 * The error message set by
1578 * verify_refname_available_dir() is OK.
1579 */
1580 ret = TRANSACTION_NAME_CONFLICT;
1581 }
1582 } else {
1583 /*
1584 * The file that is in the way isn't a loose
1585 * reference. Report it as a low-level
1586 * failure.
1587 */
1588 strbuf_addf(err, "unable to create lock file %s.lock; "
1589 "non-directory in the way",
1590 ref_file.buf);
1591 }
1592 goto error_return;
1593 case SCLD_VANISHED:
1594 /* Maybe another process was tidying up. Try again. */
1595 if (--attempts_remaining > 0)
1596 goto retry;
1597 /* fall through */
1598 default:
1599 strbuf_addf(err, "unable to create directory for %s",
1600 ref_file.buf);
1601 goto error_return;
1602 }
1603
1604 if (!lock->lk)
1605 lock->lk = xcalloc(1, sizeof(struct lock_file));
1606
1607 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
1608 if (errno == ENOENT && --attempts_remaining > 0) {
1609 /*
1610 * Maybe somebody just deleted one of the
1611 * directories leading to ref_file. Try
1612 * again:
1613 */
1614 goto retry;
1615 } else {
1616 unable_to_lock_message(ref_file.buf, errno, err);
1617 goto error_return;
1618 }
1619 }
1620
1621 /*
1622 * Now we hold the lock and can read the reference without
1623 * fear that its value will change.
1624 */
1625
e1e33b72
MH
1626 if (files_read_raw_ref(ref_store, refname,
1627 lock->old_oid.hash, referent, type)) {
92b1551b
MH
1628 if (errno == ENOENT) {
1629 if (mustexist) {
1630 /* Garden variety missing reference. */
1631 strbuf_addf(err, "unable to resolve reference '%s'",
1632 refname);
1633 goto error_return;
1634 } else {
1635 /*
1636 * Reference is missing, but that's OK. We
1637 * know that there is not a conflict with
1638 * another loose reference because
1639 * (supposing that we are trying to lock
1640 * reference "refs/foo/bar"):
1641 *
1642 * - We were successfully able to create
1643 * the lockfile refs/foo/bar.lock, so we
1644 * know there cannot be a loose reference
1645 * named "refs/foo".
1646 *
1647 * - We got ENOENT and not EISDIR, so we
1648 * know that there cannot be a loose
1649 * reference named "refs/foo/bar/baz".
1650 */
1651 }
1652 } else if (errno == EISDIR) {
1653 /*
1654 * There is a directory in the way. It might have
1655 * contained references that have been deleted. If
1656 * we don't require that the reference already
1657 * exists, try to remove the directory so that it
1658 * doesn't cause trouble when we want to rename the
1659 * lockfile into place later.
1660 */
1661 if (mustexist) {
1662 /* Garden variety missing reference. */
1663 strbuf_addf(err, "unable to resolve reference '%s'",
1664 refname);
1665 goto error_return;
1666 } else if (remove_dir_recursively(&ref_file,
1667 REMOVE_DIR_EMPTY_ONLY)) {
1668 if (verify_refname_available_dir(
1669 refname, extras, skip,
00eebe35 1670 get_loose_refs(refs),
92b1551b
MH
1671 err)) {
1672 /*
1673 * The error message set by
1674 * verify_refname_available() is OK.
1675 */
1676 ret = TRANSACTION_NAME_CONFLICT;
1677 goto error_return;
1678 } else {
1679 /*
1680 * We can't delete the directory,
1681 * but we also don't know of any
1682 * references that it should
1683 * contain.
1684 */
1685 strbuf_addf(err, "there is a non-empty directory '%s' "
1686 "blocking reference '%s'",
1687 ref_file.buf, refname);
1688 goto error_return;
1689 }
1690 }
1691 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
1692 strbuf_addf(err, "unable to resolve reference '%s': "
1693 "reference broken", refname);
1694 goto error_return;
1695 } else {
1696 strbuf_addf(err, "unable to resolve reference '%s': %s",
1697 refname, strerror(errno));
1698 goto error_return;
1699 }
1700
1701 /*
1702 * If the ref did not exist and we are creating it,
1703 * make sure there is no existing packed ref whose
1704 * name begins with our refname, nor a packed ref
1705 * whose name is a proper prefix of our refname.
1706 */
1707 if (verify_refname_available_dir(
1708 refname, extras, skip,
00eebe35 1709 get_packed_refs(refs),
92b1551b
MH
1710 err)) {
1711 goto error_return;
1712 }
1713 }
1714
1715 ret = 0;
1716 goto out;
1717
1718error_return:
1719 unlock_ref(lock);
1720 *lock_p = NULL;
1721
1722out:
1723 strbuf_release(&ref_file);
1724 return ret;
1725}
1726
7bd9bcf3
MH
1727/*
1728 * Peel the entry (if possible) and return its new peel_status. If
1729 * repeel is true, re-peel the entry even if there is an old peeled
1730 * value that is already stored in it.
1731 *
1732 * It is OK to call this function with a packed reference entry that
1733 * might be stale and might even refer to an object that has since
1734 * been garbage-collected. In such a case, if the entry has
1735 * REF_KNOWS_PEELED then leave the status unchanged and return
1736 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1737 */
1738static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1739{
1740 enum peel_status status;
1741
1742 if (entry->flag & REF_KNOWS_PEELED) {
1743 if (repeel) {
1744 entry->flag &= ~REF_KNOWS_PEELED;
1745 oidclr(&entry->u.value.peeled);
1746 } else {
1747 return is_null_oid(&entry->u.value.peeled) ?
1748 PEEL_NON_TAG : PEEL_PEELED;
1749 }
1750 }
1751 if (entry->flag & REF_ISBROKEN)
1752 return PEEL_BROKEN;
1753 if (entry->flag & REF_ISSYMREF)
1754 return PEEL_IS_SYMREF;
1755
1756 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1757 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1758 entry->flag |= REF_KNOWS_PEELED;
1759 return status;
1760}
1761
1762int peel_ref(const char *refname, unsigned char *sha1)
1763{
f0d21efc 1764 struct files_ref_store *refs = get_files_ref_store(NULL, "peel_ref");
7bd9bcf3
MH
1765 int flag;
1766 unsigned char base[20];
1767
4c4de895
MH
1768 if (current_ref_iter && current_ref_iter->refname == refname) {
1769 struct object_id peeled;
1770
1771 if (ref_iterator_peel(current_ref_iter, &peeled))
7bd9bcf3 1772 return -1;
4c4de895 1773 hashcpy(sha1, peeled.hash);
7bd9bcf3
MH
1774 return 0;
1775 }
1776
1777 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1778 return -1;
1779
1780 /*
1781 * If the reference is packed, read its ref_entry from the
1782 * cache in the hope that we already know its peeled value.
1783 * We only try this optimization on packed references because
1784 * (a) forcing the filling of the loose reference cache could
1785 * be expensive and (b) loose references anyway usually do not
1786 * have REF_KNOWS_PEELED.
1787 */
1788 if (flag & REF_ISPACKED) {
f0d21efc 1789 struct ref_entry *r = get_packed_ref(refs, refname);
7bd9bcf3
MH
1790 if (r) {
1791 if (peel_entry(r, 0))
1792 return -1;
1793 hashcpy(sha1, r->u.value.peeled.hash);
1794 return 0;
1795 }
1796 }
1797
1798 return peel_object(base, sha1);
1799}
1800
3bc581b9
MH
1801struct files_ref_iterator {
1802 struct ref_iterator base;
1803
1804 struct packed_ref_cache *packed_ref_cache;
1805 struct ref_iterator *iter0;
1806 unsigned int flags;
1807};
1808
1809static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
1810{
1811 struct files_ref_iterator *iter =
1812 (struct files_ref_iterator *)ref_iterator;
1813 int ok;
1814
1815 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
1816 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
1817 !ref_resolves_to_object(iter->iter0->refname,
1818 iter->iter0->oid,
1819 iter->iter0->flags))
1820 continue;
1821
1822 iter->base.refname = iter->iter0->refname;
1823 iter->base.oid = iter->iter0->oid;
1824 iter->base.flags = iter->iter0->flags;
1825 return ITER_OK;
1826 }
1827
1828 iter->iter0 = NULL;
1829 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
1830 ok = ITER_ERROR;
1831
1832 return ok;
1833}
1834
1835static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
1836 struct object_id *peeled)
1837{
1838 struct files_ref_iterator *iter =
1839 (struct files_ref_iterator *)ref_iterator;
1840
1841 return ref_iterator_peel(iter->iter0, peeled);
1842}
1843
1844static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
1845{
1846 struct files_ref_iterator *iter =
1847 (struct files_ref_iterator *)ref_iterator;
1848 int ok = ITER_DONE;
1849
1850 if (iter->iter0)
1851 ok = ref_iterator_abort(iter->iter0);
1852
1853 release_packed_ref_cache(iter->packed_ref_cache);
1854 base_ref_iterator_free(ref_iterator);
1855 return ok;
1856}
1857
1858static struct ref_iterator_vtable files_ref_iterator_vtable = {
1859 files_ref_iterator_advance,
1860 files_ref_iterator_peel,
1861 files_ref_iterator_abort
1862};
1863
1864struct ref_iterator *files_ref_iterator_begin(
1865 const char *submodule,
1866 const char *prefix, unsigned int flags)
1867{
00eebe35
MH
1868 struct files_ref_store *refs =
1869 get_files_ref_store(submodule, "ref_iterator_begin");
3bc581b9
MH
1870 struct ref_dir *loose_dir, *packed_dir;
1871 struct ref_iterator *loose_iter, *packed_iter;
1872 struct files_ref_iterator *iter;
1873 struct ref_iterator *ref_iterator;
1874
1875 if (!refs)
1876 return empty_ref_iterator_begin();
1877
1878 if (ref_paranoia < 0)
1879 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1880 if (ref_paranoia)
1881 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1882
1883 iter = xcalloc(1, sizeof(*iter));
1884 ref_iterator = &iter->base;
1885 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
1886
1887 /*
1888 * We must make sure that all loose refs are read before
1889 * accessing the packed-refs file; this avoids a race
1890 * condition if loose refs are migrated to the packed-refs
1891 * file by a simultaneous process, but our in-memory view is
1892 * from before the migration. We ensure this as follows:
1893 * First, we call prime_ref_dir(), which pre-reads the loose
1894 * references for the subtree into the cache. (If they've
1895 * already been read, that's OK; we only need to guarantee
1896 * that they're read before the packed refs, not *how much*
1897 * before.) After that, we call get_packed_ref_cache(), which
1898 * internally checks whether the packed-ref cache is up to
1899 * date with what is on disk, and re-reads it if not.
1900 */
1901
1902 loose_dir = get_loose_refs(refs);
1903
1904 if (prefix && *prefix)
1905 loose_dir = find_containing_dir(loose_dir, prefix, 0);
1906
1907 if (loose_dir) {
1908 prime_ref_dir(loose_dir);
1909 loose_iter = cache_ref_iterator_begin(loose_dir);
1910 } else {
1911 /* There's nothing to iterate over. */
1912 loose_iter = empty_ref_iterator_begin();
1913 }
1914
1915 iter->packed_ref_cache = get_packed_ref_cache(refs);
1916 acquire_packed_ref_cache(iter->packed_ref_cache);
1917 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);
1918
1919 if (prefix && *prefix)
1920 packed_dir = find_containing_dir(packed_dir, prefix, 0);
1921
1922 if (packed_dir) {
1923 packed_iter = cache_ref_iterator_begin(packed_dir);
1924 } else {
1925 /* There's nothing to iterate over. */
1926 packed_iter = empty_ref_iterator_begin();
1927 }
1928
1929 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
1930 iter->flags = flags;
1931
1932 return ref_iterator;
1933}
1934
7bd9bcf3
MH
1935/*
1936 * Verify that the reference locked by lock has the value old_sha1.
1937 * Fail if the reference doesn't exist and mustexist is set. Return 0
1938 * on success. On error, write an error message to err, set errno, and
1939 * return a negative value.
1940 */
1941static int verify_lock(struct ref_lock *lock,
1942 const unsigned char *old_sha1, int mustexist,
1943 struct strbuf *err)
1944{
1945 assert(err);
1946
1947 if (read_ref_full(lock->ref_name,
1948 mustexist ? RESOLVE_REF_READING : 0,
1949 lock->old_oid.hash, NULL)) {
6294dcb4
JK
1950 if (old_sha1) {
1951 int save_errno = errno;
0568c8e9 1952 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
6294dcb4
JK
1953 errno = save_errno;
1954 return -1;
1955 } else {
1956 hashclr(lock->old_oid.hash);
1957 return 0;
1958 }
7bd9bcf3 1959 }
6294dcb4 1960 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
0568c8e9 1961 strbuf_addf(err, "ref '%s' is at %s but expected %s",
7bd9bcf3
MH
1962 lock->ref_name,
1963 sha1_to_hex(lock->old_oid.hash),
1964 sha1_to_hex(old_sha1));
1965 errno = EBUSY;
1966 return -1;
1967 }
1968 return 0;
1969}
1970
1971static int remove_empty_directories(struct strbuf *path)
1972{
1973 /*
1974 * we want to create a file but there is a directory there;
1975 * if that is an empty directory (or a directory that contains
1976 * only empty directories), remove them.
1977 */
1978 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
1979}
1980
1981/*
1982 * Locks a ref returning the lock on success and NULL on failure.
1983 * On failure errno is set to something meaningful.
1984 */
1985static struct ref_lock *lock_ref_sha1_basic(const char *refname,
1986 const unsigned char *old_sha1,
1987 const struct string_list *extras,
1988 const struct string_list *skip,
bcb497d0 1989 unsigned int flags, int *type,
7bd9bcf3
MH
1990 struct strbuf *err)
1991{
00eebe35
MH
1992 struct files_ref_store *refs =
1993 get_files_ref_store(NULL, "lock_ref_sha1_basic");
7bd9bcf3 1994 struct strbuf ref_file = STRBUF_INIT;
7bd9bcf3
MH
1995 struct ref_lock *lock;
1996 int last_errno = 0;
7a418f3a 1997 int lflags = LOCK_NO_DEREF;
7bd9bcf3 1998 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
7a418f3a 1999 int resolve_flags = RESOLVE_REF_NO_RECURSE;
7bd9bcf3 2000 int attempts_remaining = 3;
7a418f3a 2001 int resolved;
7bd9bcf3
MH
2002
2003 assert(err);
2004
2005 lock = xcalloc(1, sizeof(struct ref_lock));
2006
2007 if (mustexist)
2008 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 2009 if (flags & REF_DELETING)
7bd9bcf3 2010 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
7bd9bcf3 2011
7a418f3a
MH
2012 strbuf_git_path(&ref_file, "%s", refname);
2013 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2014 lock->old_oid.hash, type);
2015 if (!resolved && errno == EISDIR) {
7bd9bcf3
MH
2016 /*
2017 * we are trying to lock foo but we used to
2018 * have foo/bar which now does not exist;
2019 * it is normal for the empty directory 'foo'
2020 * to remain.
2021 */
7a418f3a 2022 if (remove_empty_directories(&ref_file)) {
7bd9bcf3 2023 last_errno = errno;
00eebe35
MH
2024 if (!verify_refname_available_dir(
2025 refname, extras, skip,
2026 get_loose_refs(refs), err))
7bd9bcf3 2027 strbuf_addf(err, "there are still refs under '%s'",
7a418f3a 2028 refname);
7bd9bcf3
MH
2029 goto error_return;
2030 }
7a418f3a
MH
2031 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2032 lock->old_oid.hash, type);
7bd9bcf3 2033 }
7a418f3a 2034 if (!resolved) {
7bd9bcf3
MH
2035 last_errno = errno;
2036 if (last_errno != ENOTDIR ||
00eebe35
MH
2037 !verify_refname_available_dir(
2038 refname, extras, skip,
2039 get_loose_refs(refs), err))
0568c8e9 2040 strbuf_addf(err, "unable to resolve reference '%s': %s",
7a418f3a 2041 refname, strerror(last_errno));
7bd9bcf3
MH
2042
2043 goto error_return;
2044 }
2859dcd4 2045
7bd9bcf3
MH
2046 /*
2047 * If the ref did not exist and we are creating it, make sure
2048 * there is no existing packed ref whose name begins with our
2049 * refname, nor a packed ref whose name is a proper prefix of
2050 * our refname.
2051 */
2052 if (is_null_oid(&lock->old_oid) &&
2053 verify_refname_available_dir(refname, extras, skip,
00eebe35
MH
2054 get_packed_refs(refs),
2055 err)) {
7bd9bcf3
MH
2056 last_errno = ENOTDIR;
2057 goto error_return;
2058 }
2059
2060 lock->lk = xcalloc(1, sizeof(struct lock_file));
2061
7bd9bcf3 2062 lock->ref_name = xstrdup(refname);
7bd9bcf3
MH
2063
2064 retry:
2065 switch (safe_create_leading_directories_const(ref_file.buf)) {
2066 case SCLD_OK:
2067 break; /* success */
2068 case SCLD_VANISHED:
2069 if (--attempts_remaining > 0)
2070 goto retry;
2071 /* fall through */
2072 default:
2073 last_errno = errno;
0568c8e9 2074 strbuf_addf(err, "unable to create directory for '%s'",
7bd9bcf3
MH
2075 ref_file.buf);
2076 goto error_return;
2077 }
2078
2079 if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {
2080 last_errno = errno;
2081 if (errno == ENOENT && --attempts_remaining > 0)
2082 /*
2083 * Maybe somebody just deleted one of the
2084 * directories leading to ref_file. Try
2085 * again:
2086 */
2087 goto retry;
2088 else {
2089 unable_to_lock_message(ref_file.buf, errno, err);
2090 goto error_return;
2091 }
2092 }
6294dcb4 2093 if (verify_lock(lock, old_sha1, mustexist, err)) {
7bd9bcf3
MH
2094 last_errno = errno;
2095 goto error_return;
2096 }
2097 goto out;
2098
2099 error_return:
2100 unlock_ref(lock);
2101 lock = NULL;
2102
2103 out:
2104 strbuf_release(&ref_file);
7bd9bcf3
MH
2105 errno = last_errno;
2106 return lock;
2107}
2108
2109/*
2110 * Write an entry to the packed-refs file for the specified refname.
2111 * If peeled is non-NULL, write it as the entry's peeled value.
2112 */
2113static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2114 unsigned char *peeled)
2115{
2116 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2117 if (peeled)
2118 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2119}
2120
2121/*
2122 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2123 */
2124static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2125{
2126 enum peel_status peel_status = peel_entry(entry, 0);
2127
2128 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2129 error("internal error: %s is not a valid packed reference!",
2130 entry->name);
2131 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2132 peel_status == PEEL_PEELED ?
2133 entry->u.value.peeled.hash : NULL);
2134 return 0;
2135}
2136
2137/*
2138 * Lock the packed-refs file for writing. Flags is passed to
2139 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2140 * errno appropriately and return a nonzero value.
2141 */
49c0df6a 2142static int lock_packed_refs(struct files_ref_store *refs, int flags)
7bd9bcf3
MH
2143{
2144 static int timeout_configured = 0;
2145 static int timeout_value = 1000;
7bd9bcf3
MH
2146 struct packed_ref_cache *packed_ref_cache;
2147
49c0df6a
MH
2148 assert_main_repository(&refs->base, "lock_packed_refs");
2149
7bd9bcf3
MH
2150 if (!timeout_configured) {
2151 git_config_get_int("core.packedrefstimeout", &timeout_value);
2152 timeout_configured = 1;
2153 }
2154
2155 if (hold_lock_file_for_update_timeout(
2156 &packlock, git_path("packed-refs"),
2157 flags, timeout_value) < 0)
2158 return -1;
2159 /*
2160 * Get the current packed-refs while holding the lock. If the
2161 * packed-refs file has been modified since we last read it,
2162 * this will automatically invalidate the cache and re-read
2163 * the packed-refs file.
2164 */
00eebe35 2165 packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
2166 packed_ref_cache->lock = &packlock;
2167 /* Increment the reference count to prevent it from being freed: */
2168 acquire_packed_ref_cache(packed_ref_cache);
2169 return 0;
2170}
2171
2172/*
2173 * Write the current version of the packed refs cache from memory to
2174 * disk. The packed-refs file must already be locked for writing (see
2175 * lock_packed_refs()). Return zero on success. On errors, set errno
2176 * and return a nonzero value
2177 */
49c0df6a 2178static int commit_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2179{
2180 struct packed_ref_cache *packed_ref_cache =
00eebe35 2181 get_packed_ref_cache(refs);
7bd9bcf3
MH
2182 int error = 0;
2183 int save_errno = 0;
2184 FILE *out;
2185
49c0df6a
MH
2186 assert_main_repository(&refs->base, "commit_packed_refs");
2187
7bd9bcf3
MH
2188 if (!packed_ref_cache->lock)
2189 die("internal error: packed-refs not locked");
2190
2191 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2192 if (!out)
2193 die_errno("unable to fdopen packed-refs descriptor");
2194
2195 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2196 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2197 0, write_packed_entry_fn, out);
2198
2199 if (commit_lock_file(packed_ref_cache->lock)) {
2200 save_errno = errno;
2201 error = -1;
2202 }
2203 packed_ref_cache->lock = NULL;
2204 release_packed_ref_cache(packed_ref_cache);
2205 errno = save_errno;
2206 return error;
2207}
2208
2209/*
2210 * Rollback the lockfile for the packed-refs file, and discard the
2211 * in-memory packed reference cache. (The packed-refs file will be
2212 * read anew if it is needed again after this function is called.)
2213 */
49c0df6a 2214static void rollback_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2215{
2216 struct packed_ref_cache *packed_ref_cache =
00eebe35 2217 get_packed_ref_cache(refs);
7bd9bcf3 2218
49c0df6a
MH
2219 assert_main_repository(&refs->base, "rollback_packed_refs");
2220
7bd9bcf3
MH
2221 if (!packed_ref_cache->lock)
2222 die("internal error: packed-refs not locked");
2223 rollback_lock_file(packed_ref_cache->lock);
2224 packed_ref_cache->lock = NULL;
2225 release_packed_ref_cache(packed_ref_cache);
00eebe35 2226 clear_packed_ref_cache(refs);
7bd9bcf3
MH
2227}
2228
2229struct ref_to_prune {
2230 struct ref_to_prune *next;
2231 unsigned char sha1[20];
2232 char name[FLEX_ARRAY];
2233};
2234
2235struct pack_refs_cb_data {
2236 unsigned int flags;
2237 struct ref_dir *packed_refs;
2238 struct ref_to_prune *ref_to_prune;
2239};
2240
2241/*
2242 * An each_ref_entry_fn that is run over loose references only. If
2243 * the loose reference can be packed, add an entry in the packed ref
2244 * cache. If the reference should be pruned, also add it to
2245 * ref_to_prune in the pack_refs_cb_data.
2246 */
2247static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2248{
2249 struct pack_refs_cb_data *cb = cb_data;
2250 enum peel_status peel_status;
2251 struct ref_entry *packed_entry;
2252 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2253
2254 /* Do not pack per-worktree refs: */
2255 if (ref_type(entry->name) != REF_TYPE_NORMAL)
2256 return 0;
2257
2258 /* ALWAYS pack tags */
2259 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2260 return 0;
2261
2262 /* Do not pack symbolic or broken refs: */
ffeef642 2263 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))
7bd9bcf3
MH
2264 return 0;
2265
2266 /* Add a packed ref cache entry equivalent to the loose entry. */
2267 peel_status = peel_entry(entry, 1);
2268 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2269 die("internal error peeling reference %s (%s)",
2270 entry->name, oid_to_hex(&entry->u.value.oid));
2271 packed_entry = find_ref(cb->packed_refs, entry->name);
2272 if (packed_entry) {
2273 /* Overwrite existing packed entry with info from loose entry */
2274 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2275 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2276 } else {
2277 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2278 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2279 add_ref(cb->packed_refs, packed_entry);
2280 }
2281 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2282
2283 /* Schedule the loose reference for pruning if requested. */
2284 if ((cb->flags & PACK_REFS_PRUNE)) {
96ffc06f
JK
2285 struct ref_to_prune *n;
2286 FLEX_ALLOC_STR(n, name, entry->name);
7bd9bcf3 2287 hashcpy(n->sha1, entry->u.value.oid.hash);
7bd9bcf3
MH
2288 n->next = cb->ref_to_prune;
2289 cb->ref_to_prune = n;
2290 }
2291 return 0;
2292}
2293
2294/*
2295 * Remove empty parents, but spare refs/ and immediate subdirs.
2296 * Note: munges *name.
2297 */
2298static void try_remove_empty_parents(char *name)
2299{
2300 char *p, *q;
2301 int i;
2302 p = name;
2303 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2304 while (*p && *p != '/')
2305 p++;
2306 /* tolerate duplicate slashes; see check_refname_format() */
2307 while (*p == '/')
2308 p++;
2309 }
2310 for (q = p; *q; q++)
2311 ;
2312 while (1) {
2313 while (q > p && *q != '/')
2314 q--;
2315 while (q > p && *(q-1) == '/')
2316 q--;
2317 if (q == p)
2318 break;
2319 *q = '\0';
2320 if (rmdir(git_path("%s", name)))
2321 break;
2322 }
2323}
2324
2325/* make sure nobody touched the ref, and unlink */
2326static void prune_ref(struct ref_to_prune *r)
2327{
2328 struct ref_transaction *transaction;
2329 struct strbuf err = STRBUF_INIT;
2330
2331 if (check_refname_format(r->name, 0))
2332 return;
2333
2334 transaction = ref_transaction_begin(&err);
2335 if (!transaction ||
2336 ref_transaction_delete(transaction, r->name, r->sha1,
c52ce248 2337 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
7bd9bcf3
MH
2338 ref_transaction_commit(transaction, &err)) {
2339 ref_transaction_free(transaction);
2340 error("%s", err.buf);
2341 strbuf_release(&err);
2342 return;
2343 }
2344 ref_transaction_free(transaction);
2345 strbuf_release(&err);
2346 try_remove_empty_parents(r->name);
2347}
2348
2349static void prune_refs(struct ref_to_prune *r)
2350{
2351 while (r) {
2352 prune_ref(r);
2353 r = r->next;
2354 }
2355}
2356
2357int pack_refs(unsigned int flags)
2358{
00eebe35
MH
2359 struct files_ref_store *refs =
2360 get_files_ref_store(NULL, "pack_refs");
7bd9bcf3
MH
2361 struct pack_refs_cb_data cbdata;
2362
2363 memset(&cbdata, 0, sizeof(cbdata));
2364 cbdata.flags = flags;
2365
49c0df6a 2366 lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
00eebe35 2367 cbdata.packed_refs = get_packed_refs(refs);
7bd9bcf3 2368
00eebe35 2369 do_for_each_entry_in_dir(get_loose_refs(refs), 0,
7bd9bcf3
MH
2370 pack_if_possible_fn, &cbdata);
2371
49c0df6a 2372 if (commit_packed_refs(refs))
7bd9bcf3
MH
2373 die_errno("unable to overwrite old ref-pack file");
2374
2375 prune_refs(cbdata.ref_to_prune);
2376 return 0;
2377}
2378
2379/*
2380 * Rewrite the packed-refs file, omitting any refs listed in
2381 * 'refnames'. On error, leave packed-refs unchanged, write an error
2382 * message to 'err', and return a nonzero value.
2383 *
2384 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2385 */
2386static int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2387{
00eebe35
MH
2388 struct files_ref_store *refs =
2389 get_files_ref_store(NULL, "repack_without_refs");
7bd9bcf3
MH
2390 struct ref_dir *packed;
2391 struct string_list_item *refname;
2392 int ret, needs_repacking = 0, removed = 0;
2393
2394 assert(err);
2395
2396 /* Look for a packed ref */
2397 for_each_string_list_item(refname, refnames) {
f0d21efc 2398 if (get_packed_ref(refs, refname->string)) {
7bd9bcf3
MH
2399 needs_repacking = 1;
2400 break;
2401 }
2402 }
2403
2404 /* Avoid locking if we have nothing to do */
2405 if (!needs_repacking)
2406 return 0; /* no refname exists in packed refs */
2407
49c0df6a 2408 if (lock_packed_refs(refs, 0)) {
7bd9bcf3
MH
2409 unable_to_lock_message(git_path("packed-refs"), errno, err);
2410 return -1;
2411 }
00eebe35 2412 packed = get_packed_refs(refs);
7bd9bcf3
MH
2413
2414 /* Remove refnames from the cache */
2415 for_each_string_list_item(refname, refnames)
2416 if (remove_entry(packed, refname->string) != -1)
2417 removed = 1;
2418 if (!removed) {
2419 /*
2420 * All packed entries disappeared while we were
2421 * acquiring the lock.
2422 */
49c0df6a 2423 rollback_packed_refs(refs);
7bd9bcf3
MH
2424 return 0;
2425 }
2426
2427 /* Write what remains */
49c0df6a 2428 ret = commit_packed_refs(refs);
7bd9bcf3
MH
2429 if (ret)
2430 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2431 strerror(errno));
2432 return ret;
2433}
2434
2435static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2436{
2437 assert(err);
2438
2439 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2440 /*
2441 * loose. The loose file name is the same as the
2442 * lockfile name, minus ".lock":
2443 */
2444 char *loose_filename = get_locked_file_path(lock->lk);
2445 int res = unlink_or_msg(loose_filename, err);
2446 free(loose_filename);
2447 if (res)
2448 return 1;
2449 }
2450 return 0;
2451}
2452
c5f04ddd 2453int delete_refs(struct string_list *refnames, unsigned int flags)
7bd9bcf3
MH
2454{
2455 struct strbuf err = STRBUF_INIT;
2456 int i, result = 0;
2457
2458 if (!refnames->nr)
2459 return 0;
2460
2461 result = repack_without_refs(refnames, &err);
2462 if (result) {
2463 /*
2464 * If we failed to rewrite the packed-refs file, then
2465 * it is unsafe to try to remove loose refs, because
2466 * doing so might expose an obsolete packed value for
2467 * a reference that might even point at an object that
2468 * has been garbage collected.
2469 */
2470 if (refnames->nr == 1)
2471 error(_("could not delete reference %s: %s"),
2472 refnames->items[0].string, err.buf);
2473 else
2474 error(_("could not delete references: %s"), err.buf);
2475
2476 goto out;
2477 }
2478
2479 for (i = 0; i < refnames->nr; i++) {
2480 const char *refname = refnames->items[i].string;
2481
c5f04ddd 2482 if (delete_ref(refname, NULL, flags))
7bd9bcf3
MH
2483 result |= error(_("could not remove reference %s"), refname);
2484 }
2485
2486out:
2487 strbuf_release(&err);
2488 return result;
2489}
2490
2491/*
2492 * People using contrib's git-new-workdir have .git/logs/refs ->
2493 * /some/other/path/.git/logs/refs, and that may live on another device.
2494 *
2495 * IOW, to avoid cross device rename errors, the temporary renamed log must
2496 * live into logs/refs.
2497 */
2498#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2499
2500static int rename_tmp_log(const char *newrefname)
2501{
2502 int attempts_remaining = 4;
2503 struct strbuf path = STRBUF_INIT;
2504 int ret = -1;
2505
2506 retry:
2507 strbuf_reset(&path);
2508 strbuf_git_path(&path, "logs/%s", newrefname);
2509 switch (safe_create_leading_directories_const(path.buf)) {
2510 case SCLD_OK:
2511 break; /* success */
2512 case SCLD_VANISHED:
2513 if (--attempts_remaining > 0)
2514 goto retry;
2515 /* fall through */
2516 default:
2517 error("unable to create directory for %s", newrefname);
2518 goto out;
2519 }
2520
2521 if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
2522 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2523 /*
2524 * rename(a, b) when b is an existing
2525 * directory ought to result in ISDIR, but
2526 * Solaris 5.8 gives ENOTDIR. Sheesh.
2527 */
2528 if (remove_empty_directories(&path)) {
2529 error("Directory not empty: logs/%s", newrefname);
2530 goto out;
2531 }
2532 goto retry;
2533 } else if (errno == ENOENT && --attempts_remaining > 0) {
2534 /*
2535 * Maybe another process just deleted one of
2536 * the directories in the path to newrefname.
2537 * Try again from the beginning.
2538 */
2539 goto retry;
2540 } else {
2541 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2542 newrefname, strerror(errno));
2543 goto out;
2544 }
2545 }
2546 ret = 0;
2547out:
2548 strbuf_release(&path);
2549 return ret;
2550}
2551
62665823
MH
2552static int files_verify_refname_available(struct ref_store *ref_store,
2553 const char *newname,
2554 const struct string_list *extras,
2555 const struct string_list *skip,
2556 struct strbuf *err)
7bd9bcf3 2557{
00eebe35 2558 struct files_ref_store *refs =
62665823 2559 files_downcast(ref_store, 1, "verify_refname_available");
00eebe35
MH
2560 struct ref_dir *packed_refs = get_packed_refs(refs);
2561 struct ref_dir *loose_refs = get_loose_refs(refs);
7bd9bcf3
MH
2562
2563 if (verify_refname_available_dir(newname, extras, skip,
2564 packed_refs, err) ||
2565 verify_refname_available_dir(newname, extras, skip,
2566 loose_refs, err))
2567 return -1;
2568
2569 return 0;
2570}
2571
7bd9bcf3
MH
2572static int write_ref_to_lockfile(struct ref_lock *lock,
2573 const unsigned char *sha1, struct strbuf *err);
2574static int commit_ref_update(struct ref_lock *lock,
2575 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2576 struct strbuf *err);
7bd9bcf3
MH
2577
2578int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2579{
2580 unsigned char sha1[20], orig_sha1[20];
2581 int flag = 0, logmoved = 0;
2582 struct ref_lock *lock;
2583 struct stat loginfo;
2584 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
7bd9bcf3
MH
2585 struct strbuf err = STRBUF_INIT;
2586
2587 if (log && S_ISLNK(loginfo.st_mode))
2588 return error("reflog for %s is a symlink", oldrefname);
2589
12fd3496
DT
2590 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2591 orig_sha1, &flag))
e711b1af
MH
2592 return error("refname %s not found", oldrefname);
2593
7bd9bcf3
MH
2594 if (flag & REF_ISSYMREF)
2595 return error("refname %s is a symbolic ref, renaming it is not supported",
2596 oldrefname);
7bd9bcf3
MH
2597 if (!rename_ref_available(oldrefname, newrefname))
2598 return 1;
2599
2600 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2601 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2602 oldrefname, strerror(errno));
2603
2604 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2605 error("unable to delete old %s", oldrefname);
2606 goto rollback;
2607 }
2608
12fd3496
DT
2609 /*
2610 * Since we are doing a shallow lookup, sha1 is not the
2611 * correct value to pass to delete_ref as old_sha1. But that
2612 * doesn't matter, because an old_sha1 check wouldn't add to
2613 * the safety anyway; we want to delete the reference whatever
2614 * its current value.
2615 */
2616 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2617 sha1, NULL) &&
2618 delete_ref(newrefname, NULL, REF_NODEREF)) {
7bd9bcf3
MH
2619 if (errno==EISDIR) {
2620 struct strbuf path = STRBUF_INIT;
2621 int result;
2622
2623 strbuf_git_path(&path, "%s", newrefname);
2624 result = remove_empty_directories(&path);
2625 strbuf_release(&path);
2626
2627 if (result) {
2628 error("Directory not empty: %s", newrefname);
2629 goto rollback;
2630 }
2631 } else {
2632 error("unable to delete existing %s", newrefname);
2633 goto rollback;
2634 }
2635 }
2636
2637 if (log && rename_tmp_log(newrefname))
2638 goto rollback;
2639
2640 logmoved = log;
2641
12fd3496
DT
2642 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, REF_NODEREF,
2643 NULL, &err);
7bd9bcf3
MH
2644 if (!lock) {
2645 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2646 strbuf_release(&err);
2647 goto rollback;
2648 }
2649 hashcpy(lock->old_oid.hash, orig_sha1);
2650
2651 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
5d9b2de4 2652 commit_ref_update(lock, orig_sha1, logmsg, &err)) {
7bd9bcf3
MH
2653 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
2654 strbuf_release(&err);
2655 goto rollback;
2656 }
2657
2658 return 0;
2659
2660 rollback:
12fd3496
DT
2661 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, REF_NODEREF,
2662 NULL, &err);
7bd9bcf3
MH
2663 if (!lock) {
2664 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2665 strbuf_release(&err);
2666 goto rollbacklog;
2667 }
2668
2669 flag = log_all_ref_updates;
2670 log_all_ref_updates = 0;
2671 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
5d9b2de4 2672 commit_ref_update(lock, orig_sha1, NULL, &err)) {
7bd9bcf3
MH
2673 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
2674 strbuf_release(&err);
2675 }
2676 log_all_ref_updates = flag;
2677
2678 rollbacklog:
2679 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2680 error("unable to restore logfile %s from %s: %s",
2681 oldrefname, newrefname, strerror(errno));
2682 if (!logmoved && log &&
2683 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2684 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2685 oldrefname, strerror(errno));
2686
2687 return 1;
2688}
2689
2690static int close_ref(struct ref_lock *lock)
2691{
2692 if (close_lock_file(lock->lk))
2693 return -1;
2694 return 0;
2695}
2696
2697static int commit_ref(struct ref_lock *lock)
2698{
5387c0d8
MH
2699 char *path = get_locked_file_path(lock->lk);
2700 struct stat st;
2701
2702 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
2703 /*
2704 * There is a directory at the path we want to rename
2705 * the lockfile to. Hopefully it is empty; try to
2706 * delete it.
2707 */
2708 size_t len = strlen(path);
2709 struct strbuf sb_path = STRBUF_INIT;
2710
2711 strbuf_attach(&sb_path, path, len, len);
2712
2713 /*
2714 * If this fails, commit_lock_file() will also fail
2715 * and will report the problem.
2716 */
2717 remove_empty_directories(&sb_path);
2718 strbuf_release(&sb_path);
2719 } else {
2720 free(path);
2721 }
2722
7bd9bcf3
MH
2723 if (commit_lock_file(lock->lk))
2724 return -1;
2725 return 0;
2726}
2727
2728/*
2729 * Create a reflog for a ref. If force_create = 0, the reflog will
2730 * only be created for certain refs (those for which
2731 * should_autocreate_reflog returns non-zero. Otherwise, create it
2732 * regardless of the ref name. Fill in *err and return -1 on failure.
2733 */
2734static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
2735{
2736 int logfd, oflags = O_APPEND | O_WRONLY;
2737
2738 strbuf_git_path(logfile, "logs/%s", refname);
2739 if (force_create || should_autocreate_reflog(refname)) {
2740 if (safe_create_leading_directories(logfile->buf) < 0) {
0568c8e9 2741 strbuf_addf(err, "unable to create directory for '%s': "
7bd9bcf3
MH
2742 "%s", logfile->buf, strerror(errno));
2743 return -1;
2744 }
2745 oflags |= O_CREAT;
2746 }
2747
2748 logfd = open(logfile->buf, oflags, 0666);
2749 if (logfd < 0) {
2750 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
2751 return 0;
2752
2753 if (errno == EISDIR) {
2754 if (remove_empty_directories(logfile)) {
0568c8e9 2755 strbuf_addf(err, "there are still logs under "
7bd9bcf3
MH
2756 "'%s'", logfile->buf);
2757 return -1;
2758 }
2759 logfd = open(logfile->buf, oflags, 0666);
2760 }
2761
2762 if (logfd < 0) {
0568c8e9 2763 strbuf_addf(err, "unable to append to '%s': %s",
7bd9bcf3
MH
2764 logfile->buf, strerror(errno));
2765 return -1;
2766 }
2767 }
2768
2769 adjust_shared_perm(logfile->buf);
2770 close(logfd);
2771 return 0;
2772}
2773
2774
2775int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)
2776{
2777 int ret;
2778 struct strbuf sb = STRBUF_INIT;
2779
2780 ret = log_ref_setup(refname, &sb, err, force_create);
2781 strbuf_release(&sb);
2782 return ret;
2783}
2784
2785static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2786 const unsigned char *new_sha1,
2787 const char *committer, const char *msg)
2788{
2789 int msglen, written;
2790 unsigned maxlen, len;
2791 char *logrec;
2792
2793 msglen = msg ? strlen(msg) : 0;
2794 maxlen = strlen(committer) + msglen + 100;
2795 logrec = xmalloc(maxlen);
2796 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2797 sha1_to_hex(old_sha1),
2798 sha1_to_hex(new_sha1),
2799 committer);
2800 if (msglen)
2801 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2802
2803 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2804 free(logrec);
2805 if (written != len)
2806 return -1;
2807
2808 return 0;
2809}
2810
2811static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
2812 const unsigned char *new_sha1, const char *msg,
2813 struct strbuf *logfile, int flags,
2814 struct strbuf *err)
2815{
2816 int logfd, result, oflags = O_APPEND | O_WRONLY;
2817
2818 if (log_all_ref_updates < 0)
2819 log_all_ref_updates = !is_bare_repository();
2820
2821 result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
2822
2823 if (result)
2824 return result;
2825
2826 logfd = open(logfile->buf, oflags);
2827 if (logfd < 0)
2828 return 0;
2829 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2830 git_committer_info(0), msg);
2831 if (result) {
0568c8e9 2832 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,
7bd9bcf3
MH
2833 strerror(errno));
2834 close(logfd);
2835 return -1;
2836 }
2837 if (close(logfd)) {
0568c8e9 2838 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,
7bd9bcf3
MH
2839 strerror(errno));
2840 return -1;
2841 }
2842 return 0;
2843}
2844
2845static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2846 const unsigned char *new_sha1, const char *msg,
2847 int flags, struct strbuf *err)
5f3c3a4e
DT
2848{
2849 return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
2850 err);
2851}
2852
2853int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
2854 const unsigned char *new_sha1, const char *msg,
2855 int flags, struct strbuf *err)
7bd9bcf3
MH
2856{
2857 struct strbuf sb = STRBUF_INIT;
2858 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
2859 err);
2860 strbuf_release(&sb);
2861 return ret;
2862}
2863
2864/*
2865 * Write sha1 into the open lockfile, then close the lockfile. On
2866 * errors, rollback the lockfile, fill in *err and
2867 * return -1.
2868 */
2869static int write_ref_to_lockfile(struct ref_lock *lock,
2870 const unsigned char *sha1, struct strbuf *err)
2871{
2872 static char term = '\n';
2873 struct object *o;
2874 int fd;
2875
2876 o = parse_object(sha1);
2877 if (!o) {
2878 strbuf_addf(err,
0568c8e9 2879 "trying to write ref '%s' with nonexistent object %s",
7bd9bcf3
MH
2880 lock->ref_name, sha1_to_hex(sha1));
2881 unlock_ref(lock);
2882 return -1;
2883 }
2884 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2885 strbuf_addf(err,
0568c8e9 2886 "trying to write non-commit object %s to branch '%s'",
7bd9bcf3
MH
2887 sha1_to_hex(sha1), lock->ref_name);
2888 unlock_ref(lock);
2889 return -1;
2890 }
2891 fd = get_lock_file_fd(lock->lk);
2892 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
2893 write_in_full(fd, &term, 1) != 1 ||
2894 close_ref(lock) < 0) {
2895 strbuf_addf(err,
0568c8e9 2896 "couldn't write '%s'", get_lock_file_path(lock->lk));
7bd9bcf3
MH
2897 unlock_ref(lock);
2898 return -1;
2899 }
2900 return 0;
2901}
2902
2903/*
2904 * Commit a change to a loose reference that has already been written
2905 * to the loose reference lockfile. Also update the reflogs if
2906 * necessary, using the specified lockmsg (which can be NULL).
2907 */
2908static int commit_ref_update(struct ref_lock *lock,
2909 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2910 struct strbuf *err)
7bd9bcf3 2911{
00eebe35
MH
2912 struct files_ref_store *refs =
2913 get_files_ref_store(NULL, "commit_ref_update");
2914
2915 clear_loose_ref_cache(refs);
7a418f3a 2916 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, 0, err)) {
7bd9bcf3 2917 char *old_msg = strbuf_detach(err, NULL);
0568c8e9 2918 strbuf_addf(err, "cannot update the ref '%s': %s",
7bd9bcf3
MH
2919 lock->ref_name, old_msg);
2920 free(old_msg);
2921 unlock_ref(lock);
2922 return -1;
2923 }
7a418f3a
MH
2924
2925 if (strcmp(lock->ref_name, "HEAD") != 0) {
7bd9bcf3
MH
2926 /*
2927 * Special hack: If a branch is updated directly and HEAD
2928 * points to it (may happen on the remote side of a push
2929 * for example) then logically the HEAD reflog should be
2930 * updated too.
2931 * A generic solution implies reverse symref information,
2932 * but finding all symrefs pointing to the given branch
2933 * would be rather costly for this rare event (the direct
2934 * update of a branch) to be worth it. So let's cheat and
2935 * check with HEAD only which should cover 99% of all usage
2936 * scenarios (even 100% of the default ones).
2937 */
2938 unsigned char head_sha1[20];
2939 int head_flag;
2940 const char *head_ref;
7a418f3a 2941
7bd9bcf3
MH
2942 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
2943 head_sha1, &head_flag);
2944 if (head_ref && (head_flag & REF_ISSYMREF) &&
2945 !strcmp(head_ref, lock->ref_name)) {
2946 struct strbuf log_err = STRBUF_INIT;
2947 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
2948 logmsg, 0, &log_err)) {
2949 error("%s", log_err.buf);
2950 strbuf_release(&log_err);
2951 }
2952 }
2953 }
7a418f3a 2954
5d9b2de4 2955 if (commit_ref(lock)) {
0568c8e9 2956 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
7bd9bcf3
MH
2957 unlock_ref(lock);
2958 return -1;
2959 }
2960
2961 unlock_ref(lock);
2962 return 0;
2963}
2964
370e5ad6 2965static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 2966{
370e5ad6 2967 int ret = -1;
7bd9bcf3 2968#ifndef NO_SYMLINK_HEAD
370e5ad6
JK
2969 char *ref_path = get_locked_file_path(lock->lk);
2970 unlink(ref_path);
2971 ret = symlink(target, ref_path);
2972 free(ref_path);
2973
2974 if (ret)
7bd9bcf3 2975 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 2976#endif
370e5ad6
JK
2977 return ret;
2978}
7bd9bcf3 2979
370e5ad6
JK
2980static void update_symref_reflog(struct ref_lock *lock, const char *refname,
2981 const char *target, const char *logmsg)
2982{
2983 struct strbuf err = STRBUF_INIT;
2984 unsigned char new_sha1[20];
b9badadd 2985 if (logmsg && !read_ref(target, new_sha1) &&
370e5ad6 2986 log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
7bd9bcf3
MH
2987 error("%s", err.buf);
2988 strbuf_release(&err);
2989 }
370e5ad6 2990}
7bd9bcf3 2991
370e5ad6
JK
2992static int create_symref_locked(struct ref_lock *lock, const char *refname,
2993 const char *target, const char *logmsg)
2994{
2995 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
2996 update_symref_reflog(lock, refname, target, logmsg);
2997 return 0;
2998 }
2999
3000 if (!fdopen_lock_file(lock->lk, "w"))
3001 return error("unable to fdopen %s: %s",
3002 lock->lk->tempfile.filename.buf, strerror(errno));
3003
396da8f7
JK
3004 update_symref_reflog(lock, refname, target, logmsg);
3005
370e5ad6
JK
3006 /* no error check; commit_ref will check ferror */
3007 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
3008 if (commit_ref(lock) < 0)
3009 return error("unable to write symref for %s: %s", refname,
3010 strerror(errno));
7bd9bcf3
MH
3011 return 0;
3012}
3013
370e5ad6
JK
3014int create_symref(const char *refname, const char *target, const char *logmsg)
3015{
3016 struct strbuf err = STRBUF_INIT;
3017 struct ref_lock *lock;
3018 int ret;
3019
3020 lock = lock_ref_sha1_basic(refname, NULL, NULL, NULL, REF_NODEREF, NULL,
3021 &err);
3022 if (!lock) {
3023 error("%s", err.buf);
3024 strbuf_release(&err);
3025 return -1;
3026 }
3027
3028 ret = create_symref_locked(lock, refname, target, logmsg);
3029 unlock_ref(lock);
3030 return ret;
3031}
3032
2233066e
KY
3033int set_worktree_head_symref(const char *gitdir, const char *target)
3034{
3035 static struct lock_file head_lock;
3036 struct ref_lock *lock;
2233066e
KY
3037 struct strbuf head_path = STRBUF_INIT;
3038 const char *head_rel;
3039 int ret;
3040
3041 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));
3042 if (hold_lock_file_for_update(&head_lock, head_path.buf,
3043 LOCK_NO_DEREF) < 0) {
18eb3a9c
KY
3044 struct strbuf err = STRBUF_INIT;
3045 unable_to_lock_message(head_path.buf, errno, &err);
2233066e
KY
3046 error("%s", err.buf);
3047 strbuf_release(&err);
3048 strbuf_release(&head_path);
3049 return -1;
3050 }
3051
3052 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for
3053 linked trees */
3054 head_rel = remove_leading_path(head_path.buf,
3055 absolute_path(get_git_common_dir()));
3056 /* to make use of create_symref_locked(), initialize ref_lock */
3057 lock = xcalloc(1, sizeof(struct ref_lock));
3058 lock->lk = &head_lock;
3059 lock->ref_name = xstrdup(head_rel);
2233066e
KY
3060
3061 ret = create_symref_locked(lock, head_rel, target, NULL);
3062
3063 unlock_ref(lock); /* will free lock */
3064 strbuf_release(&head_path);
3065 return ret;
3066}
3067
7bd9bcf3
MH
3068int reflog_exists(const char *refname)
3069{
3070 struct stat st;
3071
3072 return !lstat(git_path("logs/%s", refname), &st) &&
3073 S_ISREG(st.st_mode);
3074}
3075
3076int delete_reflog(const char *refname)
3077{
3078 return remove_path(git_path("logs/%s", refname));
3079}
3080
3081static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3082{
3083 unsigned char osha1[20], nsha1[20];
3084 char *email_end, *message;
3085 unsigned long timestamp;
3086 int tz;
3087
3088 /* old SP new SP name <email> SP time TAB msg LF */
3089 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3090 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3091 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3092 !(email_end = strchr(sb->buf + 82, '>')) ||
3093 email_end[1] != ' ' ||
3094 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3095 !message || message[0] != ' ' ||
3096 (message[1] != '+' && message[1] != '-') ||
3097 !isdigit(message[2]) || !isdigit(message[3]) ||
3098 !isdigit(message[4]) || !isdigit(message[5]))
3099 return 0; /* corrupt? */
3100 email_end[1] = '\0';
3101 tz = strtol(message + 1, NULL, 10);
3102 if (message[6] != '\t')
3103 message += 6;
3104 else
3105 message += 7;
3106 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3107}
3108
3109static char *find_beginning_of_line(char *bob, char *scan)
3110{
3111 while (bob < scan && *(--scan) != '\n')
3112 ; /* keep scanning backwards */
3113 /*
3114 * Return either beginning of the buffer, or LF at the end of
3115 * the previous line.
3116 */
3117 return scan;
3118}
3119
3120int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3121{
3122 struct strbuf sb = STRBUF_INIT;
3123 FILE *logfp;
3124 long pos;
3125 int ret = 0, at_tail = 1;
3126
3127 logfp = fopen(git_path("logs/%s", refname), "r");
3128 if (!logfp)
3129 return -1;
3130
3131 /* Jump to the end */
3132 if (fseek(logfp, 0, SEEK_END) < 0)
3133 return error("cannot seek back reflog for %s: %s",
3134 refname, strerror(errno));
3135 pos = ftell(logfp);
3136 while (!ret && 0 < pos) {
3137 int cnt;
3138 size_t nread;
3139 char buf[BUFSIZ];
3140 char *endp, *scanp;
3141
3142 /* Fill next block from the end */
3143 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3144 if (fseek(logfp, pos - cnt, SEEK_SET))
3145 return error("cannot seek back reflog for %s: %s",
3146 refname, strerror(errno));
3147 nread = fread(buf, cnt, 1, logfp);
3148 if (nread != 1)
3149 return error("cannot read %d bytes from reflog for %s: %s",
3150 cnt, refname, strerror(errno));
3151 pos -= cnt;
3152
3153 scanp = endp = buf + cnt;
3154 if (at_tail && scanp[-1] == '\n')
3155 /* Looking at the final LF at the end of the file */
3156 scanp--;
3157 at_tail = 0;
3158
3159 while (buf < scanp) {
3160 /*
3161 * terminating LF of the previous line, or the beginning
3162 * of the buffer.
3163 */
3164 char *bp;
3165
3166 bp = find_beginning_of_line(buf, scanp);
3167
3168 if (*bp == '\n') {
3169 /*
3170 * The newline is the end of the previous line,
3171 * so we know we have complete line starting
3172 * at (bp + 1). Prefix it onto any prior data
3173 * we collected for the line and process it.
3174 */
3175 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3176 scanp = bp;
3177 endp = bp + 1;
3178 ret = show_one_reflog_ent(&sb, fn, cb_data);
3179 strbuf_reset(&sb);
3180 if (ret)
3181 break;
3182 } else if (!pos) {
3183 /*
3184 * We are at the start of the buffer, and the
3185 * start of the file; there is no previous
3186 * line, and we have everything for this one.
3187 * Process it, and we can end the loop.
3188 */
3189 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3190 ret = show_one_reflog_ent(&sb, fn, cb_data);
3191 strbuf_reset(&sb);
3192 break;
3193 }
3194
3195 if (bp == buf) {
3196 /*
3197 * We are at the start of the buffer, and there
3198 * is more file to read backwards. Which means
3199 * we are in the middle of a line. Note that we
3200 * may get here even if *bp was a newline; that
3201 * just means we are at the exact end of the
3202 * previous line, rather than some spot in the
3203 * middle.
3204 *
3205 * Save away what we have to be combined with
3206 * the data from the next read.
3207 */
3208 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3209 break;
3210 }
3211 }
3212
3213 }
3214 if (!ret && sb.len)
3215 die("BUG: reverse reflog parser had leftover data");
3216
3217 fclose(logfp);
3218 strbuf_release(&sb);
3219 return ret;
3220}
3221
3222int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3223{
3224 FILE *logfp;
3225 struct strbuf sb = STRBUF_INIT;
3226 int ret = 0;
3227
3228 logfp = fopen(git_path("logs/%s", refname), "r");
3229 if (!logfp)
3230 return -1;
3231
3232 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3233 ret = show_one_reflog_ent(&sb, fn, cb_data);
3234 fclose(logfp);
3235 strbuf_release(&sb);
3236 return ret;
3237}
7bd9bcf3 3238
2880d16f
MH
3239struct files_reflog_iterator {
3240 struct ref_iterator base;
7bd9bcf3 3241
2880d16f
MH
3242 struct dir_iterator *dir_iterator;
3243 struct object_id oid;
3244};
7bd9bcf3 3245
2880d16f
MH
3246static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
3247{
3248 struct files_reflog_iterator *iter =
3249 (struct files_reflog_iterator *)ref_iterator;
3250 struct dir_iterator *diter = iter->dir_iterator;
3251 int ok;
3252
3253 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
3254 int flags;
3255
3256 if (!S_ISREG(diter->st.st_mode))
7bd9bcf3 3257 continue;
2880d16f
MH
3258 if (diter->basename[0] == '.')
3259 continue;
3260 if (ends_with(diter->basename, ".lock"))
7bd9bcf3 3261 continue;
7bd9bcf3 3262
2880d16f
MH
3263 if (read_ref_full(diter->relative_path, 0,
3264 iter->oid.hash, &flags)) {
3265 error("bad ref for %s", diter->path.buf);
3266 continue;
7bd9bcf3 3267 }
2880d16f
MH
3268
3269 iter->base.refname = diter->relative_path;
3270 iter->base.oid = &iter->oid;
3271 iter->base.flags = flags;
3272 return ITER_OK;
7bd9bcf3 3273 }
2880d16f
MH
3274
3275 iter->dir_iterator = NULL;
3276 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
3277 ok = ITER_ERROR;
3278 return ok;
3279}
3280
3281static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
3282 struct object_id *peeled)
3283{
3284 die("BUG: ref_iterator_peel() called for reflog_iterator");
3285}
3286
3287static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
3288{
3289 struct files_reflog_iterator *iter =
3290 (struct files_reflog_iterator *)ref_iterator;
3291 int ok = ITER_DONE;
3292
3293 if (iter->dir_iterator)
3294 ok = dir_iterator_abort(iter->dir_iterator);
3295
3296 base_ref_iterator_free(ref_iterator);
3297 return ok;
3298}
3299
3300static struct ref_iterator_vtable files_reflog_iterator_vtable = {
3301 files_reflog_iterator_advance,
3302 files_reflog_iterator_peel,
3303 files_reflog_iterator_abort
3304};
3305
3306struct ref_iterator *files_reflog_iterator_begin(void)
3307{
3308 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
3309 struct ref_iterator *ref_iterator = &iter->base;
3310
3311 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
3312 iter->dir_iterator = dir_iterator_begin(git_path("logs"));
3313 return ref_iterator;
7bd9bcf3
MH
3314}
3315
3316int for_each_reflog(each_ref_fn fn, void *cb_data)
3317{
2880d16f
MH
3318 return do_for_each_ref_iterator(files_reflog_iterator_begin(),
3319 fn, cb_data);
7bd9bcf3
MH
3320}
3321
3322static int ref_update_reject_duplicates(struct string_list *refnames,
3323 struct strbuf *err)
3324{
3325 int i, n = refnames->nr;
3326
3327 assert(err);
3328
3329 for (i = 1; i < n; i++)
3330 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3331 strbuf_addf(err,
0568c8e9 3332 "multiple updates for ref '%s' not allowed.",
7bd9bcf3
MH
3333 refnames->items[i].string);
3334 return 1;
3335 }
3336 return 0;
3337}
3338
165056b2 3339/*
92b1551b
MH
3340 * If update is a direct update of head_ref (the reference pointed to
3341 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
3342 */
3343static int split_head_update(struct ref_update *update,
3344 struct ref_transaction *transaction,
3345 const char *head_ref,
3346 struct string_list *affected_refnames,
3347 struct strbuf *err)
3348{
3349 struct string_list_item *item;
3350 struct ref_update *new_update;
3351
3352 if ((update->flags & REF_LOG_ONLY) ||
3353 (update->flags & REF_ISPRUNING) ||
3354 (update->flags & REF_UPDATE_VIA_HEAD))
3355 return 0;
3356
3357 if (strcmp(update->refname, head_ref))
3358 return 0;
3359
3360 /*
3361 * First make sure that HEAD is not already in the
3362 * transaction. This insertion is O(N) in the transaction
3363 * size, but it happens at most once per transaction.
3364 */
3365 item = string_list_insert(affected_refnames, "HEAD");
3366 if (item->util) {
3367 /* An entry already existed */
3368 strbuf_addf(err,
3369 "multiple updates for 'HEAD' (including one "
3370 "via its referent '%s') are not allowed",
3371 update->refname);
3372 return TRANSACTION_NAME_CONFLICT;
3373 }
3374
3375 new_update = ref_transaction_add_update(
3376 transaction, "HEAD",
3377 update->flags | REF_LOG_ONLY | REF_NODEREF,
3378 update->new_sha1, update->old_sha1,
3379 update->msg);
3380
3381 item->util = new_update;
3382
3383 return 0;
3384}
3385
3386/*
3387 * update is for a symref that points at referent and doesn't have
3388 * REF_NODEREF set. Split it into two updates:
3389 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
3390 * - A new, separate update for the referent reference
3391 * Note that the new update will itself be subject to splitting when
3392 * the iteration gets to it.
3393 */
3394static int split_symref_update(struct ref_update *update,
3395 const char *referent,
3396 struct ref_transaction *transaction,
3397 struct string_list *affected_refnames,
3398 struct strbuf *err)
3399{
3400 struct string_list_item *item;
3401 struct ref_update *new_update;
3402 unsigned int new_flags;
3403
3404 /*
3405 * First make sure that referent is not already in the
3406 * transaction. This insertion is O(N) in the transaction
3407 * size, but it happens at most once per symref in a
3408 * transaction.
3409 */
3410 item = string_list_insert(affected_refnames, referent);
3411 if (item->util) {
3412 /* An entry already existed */
3413 strbuf_addf(err,
3414 "multiple updates for '%s' (including one "
3415 "via symref '%s') are not allowed",
3416 referent, update->refname);
3417 return TRANSACTION_NAME_CONFLICT;
3418 }
3419
3420 new_flags = update->flags;
3421 if (!strcmp(update->refname, "HEAD")) {
3422 /*
3423 * Record that the new update came via HEAD, so that
3424 * when we process it, split_head_update() doesn't try
3425 * to add another reflog update for HEAD. Note that
3426 * this bit will be propagated if the new_update
3427 * itself needs to be split.
3428 */
3429 new_flags |= REF_UPDATE_VIA_HEAD;
3430 }
3431
3432 new_update = ref_transaction_add_update(
3433 transaction, referent, new_flags,
3434 update->new_sha1, update->old_sha1,
3435 update->msg);
3436
6e30b2f6
MH
3437 new_update->parent_update = update;
3438
3439 /*
3440 * Change the symbolic ref update to log only. Also, it
3441 * doesn't need to check its old SHA-1 value, as that will be
3442 * done when new_update is processed.
3443 */
92b1551b 3444 update->flags |= REF_LOG_ONLY | REF_NODEREF;
6e30b2f6 3445 update->flags &= ~REF_HAVE_OLD;
92b1551b
MH
3446
3447 item->util = new_update;
3448
3449 return 0;
3450}
3451
6e30b2f6
MH
3452/*
3453 * Return the refname under which update was originally requested.
3454 */
3455static const char *original_update_refname(struct ref_update *update)
3456{
3457 while (update->parent_update)
3458 update = update->parent_update;
3459
3460 return update->refname;
3461}
3462
92b1551b
MH
3463/*
3464 * Prepare for carrying out update:
3465 * - Lock the reference referred to by update.
3466 * - Read the reference under lock.
3467 * - Check that its old SHA-1 value (if specified) is correct, and in
3468 * any case record it in update->lock->old_oid for later use when
3469 * writing the reflog.
3470 * - If it is a symref update without REF_NODEREF, split it up into a
3471 * REF_LOG_ONLY update of the symref and add a separate update for
3472 * the referent to transaction.
3473 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
3474 * update of HEAD.
165056b2
MH
3475 */
3476static int lock_ref_for_update(struct ref_update *update,
3477 struct ref_transaction *transaction,
92b1551b 3478 const char *head_ref,
165056b2
MH
3479 struct string_list *affected_refnames,
3480 struct strbuf *err)
3481{
92b1551b
MH
3482 struct strbuf referent = STRBUF_INIT;
3483 int mustexist = (update->flags & REF_HAVE_OLD) &&
3484 !is_null_sha1(update->old_sha1);
165056b2 3485 int ret;
92b1551b 3486 struct ref_lock *lock;
165056b2 3487
92b1551b 3488 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
165056b2 3489 update->flags |= REF_DELETING;
92b1551b
MH
3490
3491 if (head_ref) {
3492 ret = split_head_update(update, transaction, head_ref,
3493 affected_refnames, err);
3494 if (ret)
3495 return ret;
3496 }
3497
3498 ret = lock_raw_ref(update->refname, mustexist,
3499 affected_refnames, NULL,
3500 &update->lock, &referent,
3501 &update->type, err);
3502
3503 if (ret) {
165056b2
MH
3504 char *reason;
3505
165056b2
MH
3506 reason = strbuf_detach(err, NULL);
3507 strbuf_addf(err, "cannot lock ref '%s': %s",
3508 update->refname, reason);
3509 free(reason);
3510 return ret;
3511 }
92b1551b
MH
3512
3513 lock = update->lock;
3514
8169d0d0 3515 if (update->type & REF_ISSYMREF) {
6e30b2f6
MH
3516 if (update->flags & REF_NODEREF) {
3517 /*
3518 * We won't be reading the referent as part of
3519 * the transaction, so we have to read it here
3520 * to record and possibly check old_sha1:
3521 */
3522 if (read_ref_full(update->refname,
3523 mustexist ? RESOLVE_REF_READING : 0,
3524 lock->old_oid.hash, NULL)) {
3525 if (update->flags & REF_HAVE_OLD) {
3526 strbuf_addf(err, "cannot lock ref '%s': "
3527 "can't resolve old value",
3528 update->refname);
3529 return TRANSACTION_GENERIC_ERROR;
3530 } else {
3531 hashclr(lock->old_oid.hash);
3532 }
3533 }
3534 if ((update->flags & REF_HAVE_OLD) &&
3535 hashcmp(lock->old_oid.hash, update->old_sha1)) {
3536 strbuf_addf(err, "cannot lock ref '%s': "
3537 "is at %s but expected %s",
3538 update->refname,
3539 sha1_to_hex(lock->old_oid.hash),
3540 sha1_to_hex(update->old_sha1));
8169d0d0 3541 return TRANSACTION_GENERIC_ERROR;
8169d0d0 3542 }
92b1551b 3543
6e30b2f6
MH
3544 } else {
3545 /*
3546 * Create a new update for the reference this
3547 * symref is pointing at. Also, we will record
3548 * and verify old_sha1 for this update as part
3549 * of processing the split-off update, so we
3550 * don't have to do it here.
3551 */
92b1551b
MH
3552 ret = split_symref_update(update, referent.buf, transaction,
3553 affected_refnames, err);
3554 if (ret)
3555 return ret;
3556 }
6e30b2f6
MH
3557 } else {
3558 struct ref_update *parent_update;
8169d0d0 3559
6e30b2f6
MH
3560 /*
3561 * If this update is happening indirectly because of a
3562 * symref update, record the old SHA-1 in the parent
3563 * update:
3564 */
3565 for (parent_update = update->parent_update;
3566 parent_update;
3567 parent_update = parent_update->parent_update) {
3568 oidcpy(&parent_update->lock->old_oid, &lock->old_oid);
3569 }
3570
3571 if ((update->flags & REF_HAVE_OLD) &&
3572 hashcmp(lock->old_oid.hash, update->old_sha1)) {
3573 if (is_null_sha1(update->old_sha1))
3574 strbuf_addf(err, "cannot lock ref '%s': reference already exists",
3575 original_update_refname(update));
3576 else
3577 strbuf_addf(err, "cannot lock ref '%s': is at %s but expected %s",
3578 original_update_refname(update),
3579 sha1_to_hex(lock->old_oid.hash),
3580 sha1_to_hex(update->old_sha1));
3581
3582 return TRANSACTION_GENERIC_ERROR;
3583 }
92b1551b
MH
3584 }
3585
165056b2
MH
3586 if ((update->flags & REF_HAVE_NEW) &&
3587 !(update->flags & REF_DELETING) &&
3588 !(update->flags & REF_LOG_ONLY)) {
92b1551b
MH
3589 if (!(update->type & REF_ISSYMREF) &&
3590 !hashcmp(lock->old_oid.hash, update->new_sha1)) {
165056b2
MH
3591 /*
3592 * The reference already has the desired
3593 * value, so we don't need to write it.
3594 */
92b1551b 3595 } else if (write_ref_to_lockfile(lock, update->new_sha1,
165056b2
MH
3596 err)) {
3597 char *write_err = strbuf_detach(err, NULL);
3598
3599 /*
3600 * The lock was freed upon failure of
3601 * write_ref_to_lockfile():
3602 */
3603 update->lock = NULL;
3604 strbuf_addf(err,
3605 "cannot update the ref '%s': %s",
3606 update->refname, write_err);
3607 free(write_err);
3608 return TRANSACTION_GENERIC_ERROR;
3609 } else {
3610 update->flags |= REF_NEEDS_COMMIT;
3611 }
3612 }
3613 if (!(update->flags & REF_NEEDS_COMMIT)) {
3614 /*
3615 * We didn't call write_ref_to_lockfile(), so
3616 * the lockfile is still open. Close it to
3617 * free up the file descriptor:
3618 */
92b1551b 3619 if (close_ref(lock)) {
165056b2
MH
3620 strbuf_addf(err, "couldn't close '%s.lock'",
3621 update->refname);
3622 return TRANSACTION_GENERIC_ERROR;
3623 }
3624 }
3625 return 0;
3626}
3627
127b42a1
RS
3628static int files_transaction_commit(struct ref_store *ref_store,
3629 struct ref_transaction *transaction,
3630 struct strbuf *err)
7bd9bcf3 3631{
00eebe35 3632 struct files_ref_store *refs =
127b42a1 3633 files_downcast(ref_store, 0, "ref_transaction_commit");
7bd9bcf3 3634 int ret = 0, i;
7bd9bcf3
MH
3635 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3636 struct string_list_item *ref_to_delete;
3637 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
92b1551b
MH
3638 char *head_ref = NULL;
3639 int head_type;
3640 struct object_id head_oid;
7bd9bcf3
MH
3641
3642 assert(err);
3643
3644 if (transaction->state != REF_TRANSACTION_OPEN)
3645 die("BUG: commit called for transaction that is not open");
3646
efe47281 3647 if (!transaction->nr) {
7bd9bcf3
MH
3648 transaction->state = REF_TRANSACTION_CLOSED;
3649 return 0;
3650 }
3651
92b1551b
MH
3652 /*
3653 * Fail if a refname appears more than once in the
3654 * transaction. (If we end up splitting up any updates using
3655 * split_symref_update() or split_head_update(), those
3656 * functions will check that the new updates don't have the
3657 * same refname as any existing ones.)
3658 */
3659 for (i = 0; i < transaction->nr; i++) {
3660 struct ref_update *update = transaction->updates[i];
3661 struct string_list_item *item =
3662 string_list_append(&affected_refnames, update->refname);
3663
3664 /*
3665 * We store a pointer to update in item->util, but at
3666 * the moment we never use the value of this field
3667 * except to check whether it is non-NULL.
3668 */
3669 item->util = update;
3670 }
7bd9bcf3
MH
3671 string_list_sort(&affected_refnames);
3672 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3673 ret = TRANSACTION_GENERIC_ERROR;
3674 goto cleanup;
3675 }
3676
92b1551b
MH
3677 /*
3678 * Special hack: If a branch is updated directly and HEAD
3679 * points to it (may happen on the remote side of a push
3680 * for example) then logically the HEAD reflog should be
3681 * updated too.
3682 *
3683 * A generic solution would require reverse symref lookups,
3684 * but finding all symrefs pointing to a given branch would be
3685 * rather costly for this rare event (the direct update of a
3686 * branch) to be worth it. So let's cheat and check with HEAD
3687 * only, which should cover 99% of all usage scenarios (even
3688 * 100% of the default ones).
3689 *
3690 * So if HEAD is a symbolic reference, then record the name of
3691 * the reference that it points to. If we see an update of
3692 * head_ref within the transaction, then split_head_update()
3693 * arranges for the reflog of HEAD to be updated, too.
3694 */
3695 head_ref = resolve_refdup("HEAD", RESOLVE_REF_NO_RECURSE,
3696 head_oid.hash, &head_type);
3697
3698 if (head_ref && !(head_type & REF_ISSYMREF)) {
3699 free(head_ref);
3700 head_ref = NULL;
3701 }
3702
7bd9bcf3
MH
3703 /*
3704 * Acquire all locks, verify old values if provided, check
3705 * that new values are valid, and write new values to the
3706 * lockfiles, ready to be activated. Only keep one lockfile
3707 * open at a time to avoid running out of file descriptors.
3708 */
efe47281
MH
3709 for (i = 0; i < transaction->nr; i++) {
3710 struct ref_update *update = transaction->updates[i];
7bd9bcf3 3711
92b1551b 3712 ret = lock_ref_for_update(update, transaction, head_ref,
165056b2
MH
3713 &affected_refnames, err);
3714 if (ret)
7bd9bcf3 3715 goto cleanup;
7bd9bcf3
MH
3716 }
3717
3718 /* Perform updates first so live commits remain referenced */
efe47281
MH
3719 for (i = 0; i < transaction->nr; i++) {
3720 struct ref_update *update = transaction->updates[i];
92b1551b 3721 struct ref_lock *lock = update->lock;
7bd9bcf3 3722
d99aa884
DT
3723 if (update->flags & REF_NEEDS_COMMIT ||
3724 update->flags & REF_LOG_ONLY) {
92b1551b
MH
3725 if (log_ref_write(lock->ref_name, lock->old_oid.hash,
3726 update->new_sha1,
3727 update->msg, update->flags, err)) {
3728 char *old_msg = strbuf_detach(err, NULL);
3729
3730 strbuf_addf(err, "cannot update the ref '%s': %s",
3731 lock->ref_name, old_msg);
3732 free(old_msg);
3733 unlock_ref(lock);
7bd9bcf3
MH
3734 update->lock = NULL;
3735 ret = TRANSACTION_GENERIC_ERROR;
3736 goto cleanup;
92b1551b
MH
3737 }
3738 }
3739 if (update->flags & REF_NEEDS_COMMIT) {
00eebe35 3740 clear_loose_ref_cache(refs);
92b1551b
MH
3741 if (commit_ref(lock)) {
3742 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
3743 unlock_ref(lock);
7bd9bcf3 3744 update->lock = NULL;
92b1551b
MH
3745 ret = TRANSACTION_GENERIC_ERROR;
3746 goto cleanup;
7bd9bcf3
MH
3747 }
3748 }
3749 }
7bd9bcf3 3750 /* Perform deletes now that updates are safely completed */
efe47281
MH
3751 for (i = 0; i < transaction->nr; i++) {
3752 struct ref_update *update = transaction->updates[i];
7bd9bcf3 3753
d99aa884
DT
3754 if (update->flags & REF_DELETING &&
3755 !(update->flags & REF_LOG_ONLY)) {
7bd9bcf3
MH
3756 if (delete_ref_loose(update->lock, update->type, err)) {
3757 ret = TRANSACTION_GENERIC_ERROR;
3758 goto cleanup;
3759 }
3760
3761 if (!(update->flags & REF_ISPRUNING))
3762 string_list_append(&refs_to_delete,
3763 update->lock->ref_name);
3764 }
3765 }
3766
3767 if (repack_without_refs(&refs_to_delete, err)) {
3768 ret = TRANSACTION_GENERIC_ERROR;
3769 goto cleanup;
3770 }
3771 for_each_string_list_item(ref_to_delete, &refs_to_delete)
3772 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
00eebe35 3773 clear_loose_ref_cache(refs);
7bd9bcf3
MH
3774
3775cleanup:
3776 transaction->state = REF_TRANSACTION_CLOSED;
3777
efe47281
MH
3778 for (i = 0; i < transaction->nr; i++)
3779 if (transaction->updates[i]->lock)
3780 unlock_ref(transaction->updates[i]->lock);
7bd9bcf3 3781 string_list_clear(&refs_to_delete, 0);
92b1551b 3782 free(head_ref);
7bd9bcf3 3783 string_list_clear(&affected_refnames, 0);
92b1551b 3784
7bd9bcf3
MH
3785 return ret;
3786}
3787
3788static int ref_present(const char *refname,
3789 const struct object_id *oid, int flags, void *cb_data)
3790{
3791 struct string_list *affected_refnames = cb_data;
3792
3793 return string_list_has_string(affected_refnames, refname);
3794}
3795
3796int initial_ref_transaction_commit(struct ref_transaction *transaction,
3797 struct strbuf *err)
3798{
d99825ab
MH
3799 struct files_ref_store *refs =
3800 get_files_ref_store(NULL, "initial_ref_transaction_commit");
7bd9bcf3 3801 int ret = 0, i;
7bd9bcf3
MH
3802 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
3803
3804 assert(err);
3805
3806 if (transaction->state != REF_TRANSACTION_OPEN)
3807 die("BUG: commit called for transaction that is not open");
3808
3809 /* Fail if a refname appears more than once in the transaction: */
efe47281
MH
3810 for (i = 0; i < transaction->nr; i++)
3811 string_list_append(&affected_refnames,
3812 transaction->updates[i]->refname);
7bd9bcf3
MH
3813 string_list_sort(&affected_refnames);
3814 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3815 ret = TRANSACTION_GENERIC_ERROR;
3816 goto cleanup;
3817 }
3818
3819 /*
3820 * It's really undefined to call this function in an active
3821 * repository or when there are existing references: we are
3822 * only locking and changing packed-refs, so (1) any
3823 * simultaneous processes might try to change a reference at
3824 * the same time we do, and (2) any existing loose versions of
3825 * the references that we are setting would have precedence
3826 * over our values. But some remote helpers create the remote
3827 * "HEAD" and "master" branches before calling this function,
3828 * so here we really only check that none of the references
3829 * that we are creating already exists.
3830 */
3831 if (for_each_rawref(ref_present, &affected_refnames))
3832 die("BUG: initial ref transaction called with existing refs");
3833
efe47281
MH
3834 for (i = 0; i < transaction->nr; i++) {
3835 struct ref_update *update = transaction->updates[i];
7bd9bcf3
MH
3836
3837 if ((update->flags & REF_HAVE_OLD) &&
3838 !is_null_sha1(update->old_sha1))
3839 die("BUG: initial ref transaction with old_sha1 set");
3840 if (verify_refname_available(update->refname,
3841 &affected_refnames, NULL,
3842 err)) {
3843 ret = TRANSACTION_NAME_CONFLICT;
3844 goto cleanup;
3845 }
3846 }
3847
49c0df6a 3848 if (lock_packed_refs(refs, 0)) {
7bd9bcf3
MH
3849 strbuf_addf(err, "unable to lock packed-refs file: %s",
3850 strerror(errno));
3851 ret = TRANSACTION_GENERIC_ERROR;
3852 goto cleanup;
3853 }
3854
efe47281
MH
3855 for (i = 0; i < transaction->nr; i++) {
3856 struct ref_update *update = transaction->updates[i];
7bd9bcf3
MH
3857
3858 if ((update->flags & REF_HAVE_NEW) &&
3859 !is_null_sha1(update->new_sha1))
d99825ab 3860 add_packed_ref(refs, update->refname, update->new_sha1);
7bd9bcf3
MH
3861 }
3862
49c0df6a 3863 if (commit_packed_refs(refs)) {