resolve_missing_loose_ref(): add a files_ref_store argument
[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/*
a8739244
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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#define MAXREFLEN (1024)
1320
1321/*
1322 * Called by resolve_gitlink_ref_recursive() after it failed to read
65a0a8e5
MH
1323 * from the loose refs in refs. Find <refname> in the packed-refs file
1324 * for the submodule.
7bd9bcf3 1325 */
65a0a8e5 1326static int resolve_gitlink_packed_ref(struct files_ref_store *refs,
7bd9bcf3
MH
1327 const char *refname, unsigned char *sha1)
1328{
1329 struct ref_entry *ref;
1330 struct ref_dir *dir = get_packed_refs(refs);
1331
1332 ref = find_ref(dir, refname);
1333 if (ref == NULL)
1334 return -1;
1335
1336 hashcpy(sha1, ref->u.value.oid.hash);
1337 return 0;
1338}
1339
65a0a8e5 1340static int resolve_gitlink_ref_recursive(struct files_ref_store *refs,
7bd9bcf3
MH
1341 const char *refname, unsigned char *sha1,
1342 int recursion)
1343{
1344 int fd, len;
1345 char buffer[128], *p;
1346 char *path;
1347
2d0663b2 1348 if (recursion > SYMREF_MAXDEPTH || strlen(refname) > MAXREFLEN)
7bd9bcf3 1349 return -1;
00eebe35
MH
1350 path = *refs->base.submodule
1351 ? git_pathdup_submodule(refs->base.submodule, "%s", refname)
7bd9bcf3
MH
1352 : git_pathdup("%s", refname);
1353 fd = open(path, O_RDONLY);
1354 free(path);
1355 if (fd < 0)
1356 return resolve_gitlink_packed_ref(refs, refname, sha1);
1357
1358 len = read(fd, buffer, sizeof(buffer)-1);
1359 close(fd);
1360 if (len < 0)
1361 return -1;
1362 while (len && isspace(buffer[len-1]))
1363 len--;
1364 buffer[len] = 0;
1365
1366 /* Was it a detached head or an old-fashioned symlink? */
1367 if (!get_sha1_hex(buffer, sha1))
1368 return 0;
1369
1370 /* Symref? */
1371 if (strncmp(buffer, "ref:", 4))
1372 return -1;
1373 p = buffer + 4;
1374 while (isspace(*p))
1375 p++;
1376
1377 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1378}
1379
1380int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1381{
f6e75467 1382 int len = strlen(path);
a2d5156c 1383 struct strbuf submodule = STRBUF_INIT;
65a0a8e5 1384 struct files_ref_store *refs;
7bd9bcf3
MH
1385
1386 while (len && path[len-1] == '/')
1387 len--;
1388 if (!len)
1389 return -1;
a2d5156c
JK
1390
1391 strbuf_add(&submodule, path, len);
00eebe35 1392 refs = get_files_ref_store(submodule.buf, "resolve_gitlink_ref");
a2d5156c 1393 if (!refs) {
2eed2780
MH
1394 strbuf_release(&submodule);
1395 return -1;
a2d5156c
JK
1396 }
1397 strbuf_release(&submodule);
7bd9bcf3 1398
f6e75467 1399 return resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
7bd9bcf3
MH
1400}
1401
1402/*
1403 * Return the ref_entry for the given refname from the packed
1404 * references. If it does not exist, return NULL.
1405 */
f0d21efc
MH
1406static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
1407 const char *refname)
7bd9bcf3 1408{
00eebe35 1409 return find_ref(get_packed_refs(refs), refname);
7bd9bcf3
MH
1410}
1411
1412/*
419c6f4c 1413 * A loose ref file doesn't exist; check for a packed ref.
7bd9bcf3 1414 */
4308651c
MH
1415static int resolve_missing_loose_ref(struct files_ref_store *refs,
1416 const char *refname,
7bd9bcf3 1417 unsigned char *sha1,
89e82389 1418 unsigned int *flags)
7bd9bcf3
MH
1419{
1420 struct ref_entry *entry;
1421
1422 /*
1423 * The loose reference file does not exist; check for a packed
1424 * reference.
1425 */
f0d21efc 1426 entry = get_packed_ref(refs, refname);
7bd9bcf3
MH
1427 if (entry) {
1428 hashcpy(sha1, entry->u.value.oid.hash);
a70a93b7 1429 *flags |= REF_ISPACKED;
7bd9bcf3
MH
1430 return 0;
1431 }
419c6f4c
MH
1432 /* refname is not a packed reference. */
1433 return -1;
7bd9bcf3
MH
1434}
1435
2d0663b2 1436int read_raw_ref(const char *refname, unsigned char *sha1,
92b38093 1437 struct strbuf *referent, unsigned int *type)
7bd9bcf3 1438{
4308651c
MH
1439 struct files_ref_store *refs =
1440 get_files_ref_store(NULL, "read_raw_ref");
42a38cf7
MH
1441 struct strbuf sb_contents = STRBUF_INIT;
1442 struct strbuf sb_path = STRBUF_INIT;
7048653a
DT
1443 const char *path;
1444 const char *buf;
1445 struct stat st;
1446 int fd;
42a38cf7
MH
1447 int ret = -1;
1448 int save_errno;
7bd9bcf3 1449
fa96ea1b 1450 *type = 0;
42a38cf7
MH
1451 strbuf_reset(&sb_path);
1452 strbuf_git_path(&sb_path, "%s", refname);
1453 path = sb_path.buf;
7bd9bcf3 1454
7048653a
DT
1455stat_ref:
1456 /*
1457 * We might have to loop back here to avoid a race
1458 * condition: first we lstat() the file, then we try
1459 * to read it as a link or as a file. But if somebody
1460 * changes the type of the file (file <-> directory
1461 * <-> symlink) between the lstat() and reading, then
1462 * we don't want to report that as an error but rather
1463 * try again starting with the lstat().
1464 */
7bd9bcf3 1465
7048653a
DT
1466 if (lstat(path, &st) < 0) {
1467 if (errno != ENOENT)
42a38cf7 1468 goto out;
4308651c 1469 if (resolve_missing_loose_ref(refs, refname, sha1, type)) {
7048653a 1470 errno = ENOENT;
42a38cf7 1471 goto out;
7bd9bcf3 1472 }
42a38cf7
MH
1473 ret = 0;
1474 goto out;
7bd9bcf3 1475 }
7bd9bcf3 1476
7048653a
DT
1477 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1478 if (S_ISLNK(st.st_mode)) {
42a38cf7
MH
1479 strbuf_reset(&sb_contents);
1480 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
7048653a 1481 if (errno == ENOENT || errno == EINVAL)
7bd9bcf3
MH
1482 /* inconsistent with lstat; retry */
1483 goto stat_ref;
1484 else
42a38cf7 1485 goto out;
7bd9bcf3 1486 }
42a38cf7
MH
1487 if (starts_with(sb_contents.buf, "refs/") &&
1488 !check_refname_format(sb_contents.buf, 0)) {
92b38093 1489 strbuf_swap(&sb_contents, referent);
3a0b6b9a 1490 *type |= REF_ISSYMREF;
42a38cf7
MH
1491 ret = 0;
1492 goto out;
7bd9bcf3 1493 }
7048653a 1494 }
7bd9bcf3 1495
7048653a
DT
1496 /* Is it a directory? */
1497 if (S_ISDIR(st.st_mode)) {
e167a567
MH
1498 /*
1499 * Even though there is a directory where the loose
1500 * ref is supposed to be, there could still be a
1501 * packed ref:
1502 */
4308651c 1503 if (resolve_missing_loose_ref(refs, refname, sha1, type)) {
e167a567
MH
1504 errno = EISDIR;
1505 goto out;
1506 }
1507 ret = 0;
42a38cf7 1508 goto out;
7048653a
DT
1509 }
1510
1511 /*
1512 * Anything else, just open it and try to use it as
1513 * a ref
1514 */
1515 fd = open(path, O_RDONLY);
1516 if (fd < 0) {
1517 if (errno == ENOENT)
1518 /* inconsistent with lstat; retry */
1519 goto stat_ref;
1520 else
42a38cf7 1521 goto out;
7048653a 1522 }
42a38cf7
MH
1523 strbuf_reset(&sb_contents);
1524 if (strbuf_read(&sb_contents, fd, 256) < 0) {
7048653a
DT
1525 int save_errno = errno;
1526 close(fd);
1527 errno = save_errno;
42a38cf7 1528 goto out;
7048653a
DT
1529 }
1530 close(fd);
42a38cf7
MH
1531 strbuf_rtrim(&sb_contents);
1532 buf = sb_contents.buf;
7048653a
DT
1533 if (starts_with(buf, "ref:")) {
1534 buf += 4;
7bd9bcf3
MH
1535 while (isspace(*buf))
1536 buf++;
7048653a 1537
92b38093
MH
1538 strbuf_reset(referent);
1539 strbuf_addstr(referent, buf);
3a0b6b9a 1540 *type |= REF_ISSYMREF;
42a38cf7
MH
1541 ret = 0;
1542 goto out;
7bd9bcf3 1543 }
7bd9bcf3 1544
7048653a
DT
1545 /*
1546 * Please note that FETCH_HEAD has additional
1547 * data after the sha.
1548 */
1549 if (get_sha1_hex(buf, sha1) ||
1550 (buf[40] != '\0' && !isspace(buf[40]))) {
3a0b6b9a 1551 *type |= REF_ISBROKEN;
7048653a 1552 errno = EINVAL;
42a38cf7 1553 goto out;
7048653a
DT
1554 }
1555
42a38cf7 1556 ret = 0;
7bd9bcf3 1557
42a38cf7
MH
1558out:
1559 save_errno = errno;
7bd9bcf3
MH
1560 strbuf_release(&sb_path);
1561 strbuf_release(&sb_contents);
42a38cf7 1562 errno = save_errno;
7bd9bcf3
MH
1563 return ret;
1564}
1565
8415d247
MH
1566static void unlock_ref(struct ref_lock *lock)
1567{
1568 /* Do not free lock->lk -- atexit() still looks at them */
1569 if (lock->lk)
1570 rollback_lock_file(lock->lk);
1571 free(lock->ref_name);
8415d247
MH
1572 free(lock);
1573}
1574
92b1551b
MH
1575/*
1576 * Lock refname, without following symrefs, and set *lock_p to point
1577 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
1578 * and type similarly to read_raw_ref().
1579 *
1580 * The caller must verify that refname is a "safe" reference name (in
1581 * the sense of refname_is_safe()) before calling this function.
1582 *
1583 * If the reference doesn't already exist, verify that refname doesn't
1584 * have a D/F conflict with any existing references. extras and skip
1585 * are passed to verify_refname_available_dir() for this check.
1586 *
1587 * If mustexist is not set and the reference is not found or is
1588 * broken, lock the reference anyway but clear sha1.
1589 *
1590 * Return 0 on success. On failure, write an error message to err and
1591 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
1592 *
1593 * Implementation note: This function is basically
1594 *
1595 * lock reference
1596 * read_raw_ref()
1597 *
1598 * but it includes a lot more code to
1599 * - Deal with possible races with other processes
1600 * - Avoid calling verify_refname_available_dir() when it can be
1601 * avoided, namely if we were successfully able to read the ref
1602 * - Generate informative error messages in the case of failure
1603 */
1604static int lock_raw_ref(const char *refname, int mustexist,
1605 const struct string_list *extras,
1606 const struct string_list *skip,
1607 struct ref_lock **lock_p,
1608 struct strbuf *referent,
1609 unsigned int *type,
1610 struct strbuf *err)
1611{
00eebe35
MH
1612 struct files_ref_store *refs =
1613 get_files_ref_store(NULL, "lock_raw_ref");
92b1551b
MH
1614 struct ref_lock *lock;
1615 struct strbuf ref_file = STRBUF_INIT;
1616 int attempts_remaining = 3;
1617 int ret = TRANSACTION_GENERIC_ERROR;
1618
1619 assert(err);
1620 *type = 0;
1621
1622 /* First lock the file so it can't change out from under us. */
1623
1624 *lock_p = lock = xcalloc(1, sizeof(*lock));
1625
1626 lock->ref_name = xstrdup(refname);
92b1551b
MH
1627 strbuf_git_path(&ref_file, "%s", refname);
1628
1629retry:
1630 switch (safe_create_leading_directories(ref_file.buf)) {
1631 case SCLD_OK:
1632 break; /* success */
1633 case SCLD_EXISTS:
1634 /*
1635 * Suppose refname is "refs/foo/bar". We just failed
1636 * to create the containing directory, "refs/foo",
1637 * because there was a non-directory in the way. This
1638 * indicates a D/F conflict, probably because of
1639 * another reference such as "refs/foo". There is no
1640 * reason to expect this error to be transitory.
1641 */
1642 if (verify_refname_available(refname, extras, skip, err)) {
1643 if (mustexist) {
1644 /*
1645 * To the user the relevant error is
1646 * that the "mustexist" reference is
1647 * missing:
1648 */
1649 strbuf_reset(err);
1650 strbuf_addf(err, "unable to resolve reference '%s'",
1651 refname);
1652 } else {
1653 /*
1654 * The error message set by
1655 * verify_refname_available_dir() is OK.
1656 */
1657 ret = TRANSACTION_NAME_CONFLICT;
1658 }
1659 } else {
1660 /*
1661 * The file that is in the way isn't a loose
1662 * reference. Report it as a low-level
1663 * failure.
1664 */
1665 strbuf_addf(err, "unable to create lock file %s.lock; "
1666 "non-directory in the way",
1667 ref_file.buf);
1668 }
1669 goto error_return;
1670 case SCLD_VANISHED:
1671 /* Maybe another process was tidying up. Try again. */
1672 if (--attempts_remaining > 0)
1673 goto retry;
1674 /* fall through */
1675 default:
1676 strbuf_addf(err, "unable to create directory for %s",
1677 ref_file.buf);
1678 goto error_return;
1679 }
1680
1681 if (!lock->lk)
1682 lock->lk = xcalloc(1, sizeof(struct lock_file));
1683
1684 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
1685 if (errno == ENOENT && --attempts_remaining > 0) {
1686 /*
1687 * Maybe somebody just deleted one of the
1688 * directories leading to ref_file. Try
1689 * again:
1690 */
1691 goto retry;
1692 } else {
1693 unable_to_lock_message(ref_file.buf, errno, err);
1694 goto error_return;
1695 }
1696 }
1697
1698 /*
1699 * Now we hold the lock and can read the reference without
1700 * fear that its value will change.
1701 */
1702
1703 if (read_raw_ref(refname, lock->old_oid.hash, referent, type)) {
1704 if (errno == ENOENT) {
1705 if (mustexist) {
1706 /* Garden variety missing reference. */
1707 strbuf_addf(err, "unable to resolve reference '%s'",
1708 refname);
1709 goto error_return;
1710 } else {
1711 /*
1712 * Reference is missing, but that's OK. We
1713 * know that there is not a conflict with
1714 * another loose reference because
1715 * (supposing that we are trying to lock
1716 * reference "refs/foo/bar"):
1717 *
1718 * - We were successfully able to create
1719 * the lockfile refs/foo/bar.lock, so we
1720 * know there cannot be a loose reference
1721 * named "refs/foo".
1722 *
1723 * - We got ENOENT and not EISDIR, so we
1724 * know that there cannot be a loose
1725 * reference named "refs/foo/bar/baz".
1726 */
1727 }
1728 } else if (errno == EISDIR) {
1729 /*
1730 * There is a directory in the way. It might have
1731 * contained references that have been deleted. If
1732 * we don't require that the reference already
1733 * exists, try to remove the directory so that it
1734 * doesn't cause trouble when we want to rename the
1735 * lockfile into place later.
1736 */
1737 if (mustexist) {
1738 /* Garden variety missing reference. */
1739 strbuf_addf(err, "unable to resolve reference '%s'",
1740 refname);
1741 goto error_return;
1742 } else if (remove_dir_recursively(&ref_file,
1743 REMOVE_DIR_EMPTY_ONLY)) {
1744 if (verify_refname_available_dir(
1745 refname, extras, skip,
00eebe35 1746 get_loose_refs(refs),
92b1551b
MH
1747 err)) {
1748 /*
1749 * The error message set by
1750 * verify_refname_available() is OK.
1751 */
1752 ret = TRANSACTION_NAME_CONFLICT;
1753 goto error_return;
1754 } else {
1755 /*
1756 * We can't delete the directory,
1757 * but we also don't know of any
1758 * references that it should
1759 * contain.
1760 */
1761 strbuf_addf(err, "there is a non-empty directory '%s' "
1762 "blocking reference '%s'",
1763 ref_file.buf, refname);
1764 goto error_return;
1765 }
1766 }
1767 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
1768 strbuf_addf(err, "unable to resolve reference '%s': "
1769 "reference broken", refname);
1770 goto error_return;
1771 } else {
1772 strbuf_addf(err, "unable to resolve reference '%s': %s",
1773 refname, strerror(errno));
1774 goto error_return;
1775 }
1776
1777 /*
1778 * If the ref did not exist and we are creating it,
1779 * make sure there is no existing packed ref whose
1780 * name begins with our refname, nor a packed ref
1781 * whose name is a proper prefix of our refname.
1782 */
1783 if (verify_refname_available_dir(
1784 refname, extras, skip,
00eebe35 1785 get_packed_refs(refs),
92b1551b
MH
1786 err)) {
1787 goto error_return;
1788 }
1789 }
1790
1791 ret = 0;
1792 goto out;
1793
1794error_return:
1795 unlock_ref(lock);
1796 *lock_p = NULL;
1797
1798out:
1799 strbuf_release(&ref_file);
1800 return ret;
1801}
1802
7bd9bcf3
MH
1803/*
1804 * Peel the entry (if possible) and return its new peel_status. If
1805 * repeel is true, re-peel the entry even if there is an old peeled
1806 * value that is already stored in it.
1807 *
1808 * It is OK to call this function with a packed reference entry that
1809 * might be stale and might even refer to an object that has since
1810 * been garbage-collected. In such a case, if the entry has
1811 * REF_KNOWS_PEELED then leave the status unchanged and return
1812 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1813 */
1814static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1815{
1816 enum peel_status status;
1817
1818 if (entry->flag & REF_KNOWS_PEELED) {
1819 if (repeel) {
1820 entry->flag &= ~REF_KNOWS_PEELED;
1821 oidclr(&entry->u.value.peeled);
1822 } else {
1823 return is_null_oid(&entry->u.value.peeled) ?
1824 PEEL_NON_TAG : PEEL_PEELED;
1825 }
1826 }
1827 if (entry->flag & REF_ISBROKEN)
1828 return PEEL_BROKEN;
1829 if (entry->flag & REF_ISSYMREF)
1830 return PEEL_IS_SYMREF;
1831
1832 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1833 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1834 entry->flag |= REF_KNOWS_PEELED;
1835 return status;
1836}
1837
1838int peel_ref(const char *refname, unsigned char *sha1)
1839{
f0d21efc 1840 struct files_ref_store *refs = get_files_ref_store(NULL, "peel_ref");
7bd9bcf3
MH
1841 int flag;
1842 unsigned char base[20];
1843
4c4de895
MH
1844 if (current_ref_iter && current_ref_iter->refname == refname) {
1845 struct object_id peeled;
1846
1847 if (ref_iterator_peel(current_ref_iter, &peeled))
7bd9bcf3 1848 return -1;
4c4de895 1849 hashcpy(sha1, peeled.hash);
7bd9bcf3
MH
1850 return 0;
1851 }
1852
1853 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1854 return -1;
1855
1856 /*
1857 * If the reference is packed, read its ref_entry from the
1858 * cache in the hope that we already know its peeled value.
1859 * We only try this optimization on packed references because
1860 * (a) forcing the filling of the loose reference cache could
1861 * be expensive and (b) loose references anyway usually do not
1862 * have REF_KNOWS_PEELED.
1863 */
1864 if (flag & REF_ISPACKED) {
f0d21efc 1865 struct ref_entry *r = get_packed_ref(refs, refname);
7bd9bcf3
MH
1866 if (r) {
1867 if (peel_entry(r, 0))
1868 return -1;
1869 hashcpy(sha1, r->u.value.peeled.hash);
1870 return 0;
1871 }
1872 }
1873
1874 return peel_object(base, sha1);
1875}
1876
3bc581b9
MH
1877struct files_ref_iterator {
1878 struct ref_iterator base;
1879
1880 struct packed_ref_cache *packed_ref_cache;
1881 struct ref_iterator *iter0;
1882 unsigned int flags;
1883};
1884
1885static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
1886{
1887 struct files_ref_iterator *iter =
1888 (struct files_ref_iterator *)ref_iterator;
1889 int ok;
1890
1891 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
1892 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
1893 !ref_resolves_to_object(iter->iter0->refname,
1894 iter->iter0->oid,
1895 iter->iter0->flags))
1896 continue;
1897
1898 iter->base.refname = iter->iter0->refname;
1899 iter->base.oid = iter->iter0->oid;
1900 iter->base.flags = iter->iter0->flags;
1901 return ITER_OK;
1902 }
1903
1904 iter->iter0 = NULL;
1905 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
1906 ok = ITER_ERROR;
1907
1908 return ok;
1909}
1910
1911static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
1912 struct object_id *peeled)
1913{
1914 struct files_ref_iterator *iter =
1915 (struct files_ref_iterator *)ref_iterator;
1916
1917 return ref_iterator_peel(iter->iter0, peeled);
1918}
1919
1920static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
1921{
1922 struct files_ref_iterator *iter =
1923 (struct files_ref_iterator *)ref_iterator;
1924 int ok = ITER_DONE;
1925
1926 if (iter->iter0)
1927 ok = ref_iterator_abort(iter->iter0);
1928
1929 release_packed_ref_cache(iter->packed_ref_cache);
1930 base_ref_iterator_free(ref_iterator);
1931 return ok;
1932}
1933
1934static struct ref_iterator_vtable files_ref_iterator_vtable = {
1935 files_ref_iterator_advance,
1936 files_ref_iterator_peel,
1937 files_ref_iterator_abort
1938};
1939
1940struct ref_iterator *files_ref_iterator_begin(
1941 const char *submodule,
1942 const char *prefix, unsigned int flags)
1943{
00eebe35
MH
1944 struct files_ref_store *refs =
1945 get_files_ref_store(submodule, "ref_iterator_begin");
3bc581b9
MH
1946 struct ref_dir *loose_dir, *packed_dir;
1947 struct ref_iterator *loose_iter, *packed_iter;
1948 struct files_ref_iterator *iter;
1949 struct ref_iterator *ref_iterator;
1950
1951 if (!refs)
1952 return empty_ref_iterator_begin();
1953
1954 if (ref_paranoia < 0)
1955 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1956 if (ref_paranoia)
1957 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1958
1959 iter = xcalloc(1, sizeof(*iter));
1960 ref_iterator = &iter->base;
1961 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
1962
1963 /*
1964 * We must make sure that all loose refs are read before
1965 * accessing the packed-refs file; this avoids a race
1966 * condition if loose refs are migrated to the packed-refs
1967 * file by a simultaneous process, but our in-memory view is
1968 * from before the migration. We ensure this as follows:
1969 * First, we call prime_ref_dir(), which pre-reads the loose
1970 * references for the subtree into the cache. (If they've
1971 * already been read, that's OK; we only need to guarantee
1972 * that they're read before the packed refs, not *how much*
1973 * before.) After that, we call get_packed_ref_cache(), which
1974 * internally checks whether the packed-ref cache is up to
1975 * date with what is on disk, and re-reads it if not.
1976 */
1977
1978 loose_dir = get_loose_refs(refs);
1979
1980 if (prefix && *prefix)
1981 loose_dir = find_containing_dir(loose_dir, prefix, 0);
1982
1983 if (loose_dir) {
1984 prime_ref_dir(loose_dir);
1985 loose_iter = cache_ref_iterator_begin(loose_dir);
1986 } else {
1987 /* There's nothing to iterate over. */
1988 loose_iter = empty_ref_iterator_begin();
1989 }
1990
1991 iter->packed_ref_cache = get_packed_ref_cache(refs);
1992 acquire_packed_ref_cache(iter->packed_ref_cache);
1993 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);
1994
1995 if (prefix && *prefix)
1996 packed_dir = find_containing_dir(packed_dir, prefix, 0);
1997
1998 if (packed_dir) {
1999 packed_iter = cache_ref_iterator_begin(packed_dir);
2000 } else {
2001 /* There's nothing to iterate over. */
2002 packed_iter = empty_ref_iterator_begin();
2003 }
2004
2005 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
2006 iter->flags = flags;
2007
2008 return ref_iterator;
2009}
2010
7bd9bcf3
MH
2011/*
2012 * Verify that the reference locked by lock has the value old_sha1.
2013 * Fail if the reference doesn't exist and mustexist is set. Return 0
2014 * on success. On error, write an error message to err, set errno, and
2015 * return a negative value.
2016 */
2017static int verify_lock(struct ref_lock *lock,
2018 const unsigned char *old_sha1, int mustexist,
2019 struct strbuf *err)
2020{
2021 assert(err);
2022
2023 if (read_ref_full(lock->ref_name,
2024 mustexist ? RESOLVE_REF_READING : 0,
2025 lock->old_oid.hash, NULL)) {
6294dcb4
JK
2026 if (old_sha1) {
2027 int save_errno = errno;
0568c8e9 2028 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
6294dcb4
JK
2029 errno = save_errno;
2030 return -1;
2031 } else {
2032 hashclr(lock->old_oid.hash);
2033 return 0;
2034 }
7bd9bcf3 2035 }
6294dcb4 2036 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
0568c8e9 2037 strbuf_addf(err, "ref '%s' is at %s but expected %s",
7bd9bcf3
MH
2038 lock->ref_name,
2039 sha1_to_hex(lock->old_oid.hash),
2040 sha1_to_hex(old_sha1));
2041 errno = EBUSY;
2042 return -1;
2043 }
2044 return 0;
2045}
2046
2047static int remove_empty_directories(struct strbuf *path)
2048{
2049 /*
2050 * we want to create a file but there is a directory there;
2051 * if that is an empty directory (or a directory that contains
2052 * only empty directories), remove them.
2053 */
2054 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
2055}
2056
2057/*
2058 * Locks a ref returning the lock on success and NULL on failure.
2059 * On failure errno is set to something meaningful.
2060 */
2061static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2062 const unsigned char *old_sha1,
2063 const struct string_list *extras,
2064 const struct string_list *skip,
bcb497d0 2065 unsigned int flags, int *type,
7bd9bcf3
MH
2066 struct strbuf *err)
2067{
00eebe35
MH
2068 struct files_ref_store *refs =
2069 get_files_ref_store(NULL, "lock_ref_sha1_basic");
7bd9bcf3 2070 struct strbuf ref_file = STRBUF_INIT;
7bd9bcf3
MH
2071 struct ref_lock *lock;
2072 int last_errno = 0;
7a418f3a 2073 int lflags = LOCK_NO_DEREF;
7bd9bcf3 2074 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
7a418f3a 2075 int resolve_flags = RESOLVE_REF_NO_RECURSE;
7bd9bcf3 2076 int attempts_remaining = 3;
7a418f3a 2077 int resolved;
7bd9bcf3
MH
2078
2079 assert(err);
2080
2081 lock = xcalloc(1, sizeof(struct ref_lock));
2082
2083 if (mustexist)
2084 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 2085 if (flags & REF_DELETING)
7bd9bcf3 2086 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
7bd9bcf3 2087
7a418f3a
MH
2088 strbuf_git_path(&ref_file, "%s", refname);
2089 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2090 lock->old_oid.hash, type);
2091 if (!resolved && errno == EISDIR) {
7bd9bcf3
MH
2092 /*
2093 * we are trying to lock foo but we used to
2094 * have foo/bar which now does not exist;
2095 * it is normal for the empty directory 'foo'
2096 * to remain.
2097 */
7a418f3a 2098 if (remove_empty_directories(&ref_file)) {
7bd9bcf3 2099 last_errno = errno;
00eebe35
MH
2100 if (!verify_refname_available_dir(
2101 refname, extras, skip,
2102 get_loose_refs(refs), err))
7bd9bcf3 2103 strbuf_addf(err, "there are still refs under '%s'",
7a418f3a 2104 refname);
7bd9bcf3
MH
2105 goto error_return;
2106 }
7a418f3a
MH
2107 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2108 lock->old_oid.hash, type);
7bd9bcf3 2109 }
7a418f3a 2110 if (!resolved) {
7bd9bcf3
MH
2111 last_errno = errno;
2112 if (last_errno != ENOTDIR ||
00eebe35
MH
2113 !verify_refname_available_dir(
2114 refname, extras, skip,
2115 get_loose_refs(refs), err))
0568c8e9 2116 strbuf_addf(err, "unable to resolve reference '%s': %s",
7a418f3a 2117 refname, strerror(last_errno));
7bd9bcf3
MH
2118
2119 goto error_return;
2120 }
2859dcd4 2121
7bd9bcf3
MH
2122 /*
2123 * If the ref did not exist and we are creating it, make sure
2124 * there is no existing packed ref whose name begins with our
2125 * refname, nor a packed ref whose name is a proper prefix of
2126 * our refname.
2127 */
2128 if (is_null_oid(&lock->old_oid) &&
2129 verify_refname_available_dir(refname, extras, skip,
00eebe35
MH
2130 get_packed_refs(refs),
2131 err)) {
7bd9bcf3
MH
2132 last_errno = ENOTDIR;
2133 goto error_return;
2134 }
2135
2136 lock->lk = xcalloc(1, sizeof(struct lock_file));
2137
7bd9bcf3 2138 lock->ref_name = xstrdup(refname);
7bd9bcf3
MH
2139
2140 retry:
2141 switch (safe_create_leading_directories_const(ref_file.buf)) {
2142 case SCLD_OK:
2143 break; /* success */
2144 case SCLD_VANISHED:
2145 if (--attempts_remaining > 0)
2146 goto retry;
2147 /* fall through */
2148 default:
2149 last_errno = errno;
0568c8e9 2150 strbuf_addf(err, "unable to create directory for '%s'",
7bd9bcf3
MH
2151 ref_file.buf);
2152 goto error_return;
2153 }
2154
2155 if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {
2156 last_errno = errno;
2157 if (errno == ENOENT && --attempts_remaining > 0)
2158 /*
2159 * Maybe somebody just deleted one of the
2160 * directories leading to ref_file. Try
2161 * again:
2162 */
2163 goto retry;
2164 else {
2165 unable_to_lock_message(ref_file.buf, errno, err);
2166 goto error_return;
2167 }
2168 }
6294dcb4 2169 if (verify_lock(lock, old_sha1, mustexist, err)) {
7bd9bcf3
MH
2170 last_errno = errno;
2171 goto error_return;
2172 }
2173 goto out;
2174
2175 error_return:
2176 unlock_ref(lock);
2177 lock = NULL;
2178
2179 out:
2180 strbuf_release(&ref_file);
7bd9bcf3
MH
2181 errno = last_errno;
2182 return lock;
2183}
2184
2185/*
2186 * Write an entry to the packed-refs file for the specified refname.
2187 * If peeled is non-NULL, write it as the entry's peeled value.
2188 */
2189static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2190 unsigned char *peeled)
2191{
2192 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2193 if (peeled)
2194 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2195}
2196
2197/*
2198 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2199 */
2200static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2201{
2202 enum peel_status peel_status = peel_entry(entry, 0);
2203
2204 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2205 error("internal error: %s is not a valid packed reference!",
2206 entry->name);
2207 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2208 peel_status == PEEL_PEELED ?
2209 entry->u.value.peeled.hash : NULL);
2210 return 0;
2211}
2212
2213/*
2214 * Lock the packed-refs file for writing. Flags is passed to
2215 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2216 * errno appropriately and return a nonzero value.
2217 */
2218static int lock_packed_refs(int flags)
2219{
00eebe35
MH
2220 struct files_ref_store *refs =
2221 get_files_ref_store(NULL, "lock_packed_refs");
7bd9bcf3
MH
2222 static int timeout_configured = 0;
2223 static int timeout_value = 1000;
7bd9bcf3
MH
2224 struct packed_ref_cache *packed_ref_cache;
2225
2226 if (!timeout_configured) {
2227 git_config_get_int("core.packedrefstimeout", &timeout_value);
2228 timeout_configured = 1;
2229 }
2230
2231 if (hold_lock_file_for_update_timeout(
2232 &packlock, git_path("packed-refs"),
2233 flags, timeout_value) < 0)
2234 return -1;
2235 /*
2236 * Get the current packed-refs while holding the lock. If the
2237 * packed-refs file has been modified since we last read it,
2238 * this will automatically invalidate the cache and re-read
2239 * the packed-refs file.
2240 */
00eebe35 2241 packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
2242 packed_ref_cache->lock = &packlock;
2243 /* Increment the reference count to prevent it from being freed: */
2244 acquire_packed_ref_cache(packed_ref_cache);
2245 return 0;
2246}
2247
2248/*
2249 * Write the current version of the packed refs cache from memory to
2250 * disk. The packed-refs file must already be locked for writing (see
2251 * lock_packed_refs()). Return zero on success. On errors, set errno
2252 * and return a nonzero value
2253 */
2254static int commit_packed_refs(void)
2255{
00eebe35
MH
2256 struct files_ref_store *refs =
2257 get_files_ref_store(NULL, "commit_packed_refs");
7bd9bcf3 2258 struct packed_ref_cache *packed_ref_cache =
00eebe35 2259 get_packed_ref_cache(refs);
7bd9bcf3
MH
2260 int error = 0;
2261 int save_errno = 0;
2262 FILE *out;
2263
2264 if (!packed_ref_cache->lock)
2265 die("internal error: packed-refs not locked");
2266
2267 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2268 if (!out)
2269 die_errno("unable to fdopen packed-refs descriptor");
2270
2271 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2272 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2273 0, write_packed_entry_fn, out);
2274
2275 if (commit_lock_file(packed_ref_cache->lock)) {
2276 save_errno = errno;
2277 error = -1;
2278 }
2279 packed_ref_cache->lock = NULL;
2280 release_packed_ref_cache(packed_ref_cache);
2281 errno = save_errno;
2282 return error;
2283}
2284
2285/*
2286 * Rollback the lockfile for the packed-refs file, and discard the
2287 * in-memory packed reference cache. (The packed-refs file will be
2288 * read anew if it is needed again after this function is called.)
2289 */
2290static void rollback_packed_refs(void)
2291{
00eebe35
MH
2292 struct files_ref_store *refs =
2293 get_files_ref_store(NULL, "rollback_packed_refs");
7bd9bcf3 2294 struct packed_ref_cache *packed_ref_cache =
00eebe35 2295 get_packed_ref_cache(refs);
7bd9bcf3
MH
2296
2297 if (!packed_ref_cache->lock)
2298 die("internal error: packed-refs not locked");
2299 rollback_lock_file(packed_ref_cache->lock);
2300 packed_ref_cache->lock = NULL;
2301 release_packed_ref_cache(packed_ref_cache);
00eebe35 2302 clear_packed_ref_cache(refs);
7bd9bcf3
MH
2303}
2304
2305struct ref_to_prune {
2306 struct ref_to_prune *next;
2307 unsigned char sha1[20];
2308 char name[FLEX_ARRAY];
2309};
2310
2311struct pack_refs_cb_data {
2312 unsigned int flags;
2313 struct ref_dir *packed_refs;
2314 struct ref_to_prune *ref_to_prune;
2315};
2316
2317/*
2318 * An each_ref_entry_fn that is run over loose references only. If
2319 * the loose reference can be packed, add an entry in the packed ref
2320 * cache. If the reference should be pruned, also add it to
2321 * ref_to_prune in the pack_refs_cb_data.
2322 */
2323static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2324{
2325 struct pack_refs_cb_data *cb = cb_data;
2326 enum peel_status peel_status;
2327 struct ref_entry *packed_entry;
2328 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2329
2330 /* Do not pack per-worktree refs: */
2331 if (ref_type(entry->name) != REF_TYPE_NORMAL)
2332 return 0;
2333
2334 /* ALWAYS pack tags */
2335 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2336 return 0;
2337
2338 /* Do not pack symbolic or broken refs: */
ffeef642 2339 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))
7bd9bcf3
MH
2340 return 0;
2341
2342 /* Add a packed ref cache entry equivalent to the loose entry. */
2343 peel_status = peel_entry(entry, 1);
2344 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2345 die("internal error peeling reference %s (%s)",
2346 entry->name, oid_to_hex(&entry->u.value.oid));
2347 packed_entry = find_ref(cb->packed_refs, entry->name);
2348 if (packed_entry) {
2349 /* Overwrite existing packed entry with info from loose entry */
2350 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2351 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2352 } else {
2353 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2354 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2355 add_ref(cb->packed_refs, packed_entry);
2356 }
2357 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2358
2359 /* Schedule the loose reference for pruning if requested. */
2360 if ((cb->flags & PACK_REFS_PRUNE)) {
96ffc06f
JK
2361 struct ref_to_prune *n;
2362 FLEX_ALLOC_STR(n, name, entry->name);
7bd9bcf3 2363 hashcpy(n->sha1, entry->u.value.oid.hash);
7bd9bcf3
MH
2364 n->next = cb->ref_to_prune;
2365 cb->ref_to_prune = n;
2366 }
2367 return 0;
2368}
2369
2370/*
2371 * Remove empty parents, but spare refs/ and immediate subdirs.
2372 * Note: munges *name.
2373 */
2374static void try_remove_empty_parents(char *name)
2375{
2376 char *p, *q;
2377 int i;
2378 p = name;
2379 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2380 while (*p && *p != '/')
2381 p++;
2382 /* tolerate duplicate slashes; see check_refname_format() */
2383 while (*p == '/')
2384 p++;
2385 }
2386 for (q = p; *q; q++)
2387 ;
2388 while (1) {
2389 while (q > p && *q != '/')
2390 q--;
2391 while (q > p && *(q-1) == '/')
2392 q--;
2393 if (q == p)
2394 break;
2395 *q = '\0';
2396 if (rmdir(git_path("%s", name)))
2397 break;
2398 }
2399}
2400
2401/* make sure nobody touched the ref, and unlink */
2402static void prune_ref(struct ref_to_prune *r)
2403{
2404 struct ref_transaction *transaction;
2405 struct strbuf err = STRBUF_INIT;
2406
2407 if (check_refname_format(r->name, 0))
2408 return;
2409
2410 transaction = ref_transaction_begin(&err);
2411 if (!transaction ||
2412 ref_transaction_delete(transaction, r->name, r->sha1,
c52ce248 2413 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
7bd9bcf3
MH
2414 ref_transaction_commit(transaction, &err)) {
2415 ref_transaction_free(transaction);
2416 error("%s", err.buf);
2417 strbuf_release(&err);
2418 return;
2419 }
2420 ref_transaction_free(transaction);
2421 strbuf_release(&err);
2422 try_remove_empty_parents(r->name);
2423}
2424
2425static void prune_refs(struct ref_to_prune *r)
2426{
2427 while (r) {
2428 prune_ref(r);
2429 r = r->next;
2430 }
2431}
2432
2433int pack_refs(unsigned int flags)
2434{
00eebe35
MH
2435 struct files_ref_store *refs =
2436 get_files_ref_store(NULL, "pack_refs");
7bd9bcf3
MH
2437 struct pack_refs_cb_data cbdata;
2438
2439 memset(&cbdata, 0, sizeof(cbdata));
2440 cbdata.flags = flags;
2441
2442 lock_packed_refs(LOCK_DIE_ON_ERROR);
00eebe35 2443 cbdata.packed_refs = get_packed_refs(refs);
7bd9bcf3 2444
00eebe35 2445 do_for_each_entry_in_dir(get_loose_refs(refs), 0,
7bd9bcf3
MH
2446 pack_if_possible_fn, &cbdata);
2447
2448 if (commit_packed_refs())
2449 die_errno("unable to overwrite old ref-pack file");
2450
2451 prune_refs(cbdata.ref_to_prune);
2452 return 0;
2453}
2454
2455/*
2456 * Rewrite the packed-refs file, omitting any refs listed in
2457 * 'refnames'. On error, leave packed-refs unchanged, write an error
2458 * message to 'err', and return a nonzero value.
2459 *
2460 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2461 */
2462static int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2463{
00eebe35
MH
2464 struct files_ref_store *refs =
2465 get_files_ref_store(NULL, "repack_without_refs");
7bd9bcf3
MH
2466 struct ref_dir *packed;
2467 struct string_list_item *refname;
2468 int ret, needs_repacking = 0, removed = 0;
2469
2470 assert(err);
2471
2472 /* Look for a packed ref */
2473 for_each_string_list_item(refname, refnames) {
f0d21efc 2474 if (get_packed_ref(refs, refname->string)) {
7bd9bcf3
MH
2475 needs_repacking = 1;
2476 break;
2477 }
2478 }
2479
2480 /* Avoid locking if we have nothing to do */
2481 if (!needs_repacking)
2482 return 0; /* no refname exists in packed refs */
2483
2484 if (lock_packed_refs(0)) {
2485 unable_to_lock_message(git_path("packed-refs"), errno, err);
2486 return -1;
2487 }
00eebe35 2488 packed = get_packed_refs(refs);
7bd9bcf3
MH
2489
2490 /* Remove refnames from the cache */
2491 for_each_string_list_item(refname, refnames)
2492 if (remove_entry(packed, refname->string) != -1)
2493 removed = 1;
2494 if (!removed) {
2495 /*
2496 * All packed entries disappeared while we were
2497 * acquiring the lock.
2498 */
2499 rollback_packed_refs();
2500 return 0;
2501 }
2502
2503 /* Write what remains */
2504 ret = commit_packed_refs();
2505 if (ret)
2506 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2507 strerror(errno));
2508 return ret;
2509}
2510
2511static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2512{
2513 assert(err);
2514
2515 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2516 /*
2517 * loose. The loose file name is the same as the
2518 * lockfile name, minus ".lock":
2519 */
2520 char *loose_filename = get_locked_file_path(lock->lk);
2521 int res = unlink_or_msg(loose_filename, err);
2522 free(loose_filename);
2523 if (res)
2524 return 1;
2525 }
2526 return 0;
2527}
2528
c5f04ddd 2529int delete_refs(struct string_list *refnames, unsigned int flags)
7bd9bcf3
MH
2530{
2531 struct strbuf err = STRBUF_INIT;
2532 int i, result = 0;
2533
2534 if (!refnames->nr)
2535 return 0;
2536
2537 result = repack_without_refs(refnames, &err);
2538 if (result) {
2539 /*
2540 * If we failed to rewrite the packed-refs file, then
2541 * it is unsafe to try to remove loose refs, because
2542 * doing so might expose an obsolete packed value for
2543 * a reference that might even point at an object that
2544 * has been garbage collected.
2545 */
2546 if (refnames->nr == 1)
2547 error(_("could not delete reference %s: %s"),
2548 refnames->items[0].string, err.buf);
2549 else
2550 error(_("could not delete references: %s"), err.buf);
2551
2552 goto out;
2553 }
2554
2555 for (i = 0; i < refnames->nr; i++) {
2556 const char *refname = refnames->items[i].string;
2557
c5f04ddd 2558 if (delete_ref(refname, NULL, flags))
7bd9bcf3
MH
2559 result |= error(_("could not remove reference %s"), refname);
2560 }
2561
2562out:
2563 strbuf_release(&err);
2564 return result;
2565}
2566
2567/*
2568 * People using contrib's git-new-workdir have .git/logs/refs ->
2569 * /some/other/path/.git/logs/refs, and that may live on another device.
2570 *
2571 * IOW, to avoid cross device rename errors, the temporary renamed log must
2572 * live into logs/refs.
2573 */
2574#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2575
2576static int rename_tmp_log(const char *newrefname)
2577{
2578 int attempts_remaining = 4;
2579 struct strbuf path = STRBUF_INIT;
2580 int ret = -1;
2581
2582 retry:
2583 strbuf_reset(&path);
2584 strbuf_git_path(&path, "logs/%s", newrefname);
2585 switch (safe_create_leading_directories_const(path.buf)) {
2586 case SCLD_OK:
2587 break; /* success */
2588 case SCLD_VANISHED:
2589 if (--attempts_remaining > 0)
2590 goto retry;
2591 /* fall through */
2592 default:
2593 error("unable to create directory for %s", newrefname);
2594 goto out;
2595 }
2596
2597 if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
2598 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2599 /*
2600 * rename(a, b) when b is an existing
2601 * directory ought to result in ISDIR, but
2602 * Solaris 5.8 gives ENOTDIR. Sheesh.
2603 */
2604 if (remove_empty_directories(&path)) {
2605 error("Directory not empty: logs/%s", newrefname);
2606 goto out;
2607 }
2608 goto retry;
2609 } else if (errno == ENOENT && --attempts_remaining > 0) {
2610 /*
2611 * Maybe another process just deleted one of
2612 * the directories in the path to newrefname.
2613 * Try again from the beginning.
2614 */
2615 goto retry;
2616 } else {
2617 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2618 newrefname, strerror(errno));
2619 goto out;
2620 }
2621 }
2622 ret = 0;
2623out:
2624 strbuf_release(&path);
2625 return ret;
2626}
2627
2628int verify_refname_available(const char *newname,
3a8af7be
MH
2629 const struct string_list *extras,
2630 const struct string_list *skip,
7bd9bcf3
MH
2631 struct strbuf *err)
2632{
00eebe35
MH
2633 struct files_ref_store *refs =
2634 get_files_ref_store(NULL, "verify_refname_available");
2635 struct ref_dir *packed_refs = get_packed_refs(refs);
2636 struct ref_dir *loose_refs = get_loose_refs(refs);
7bd9bcf3
MH
2637
2638 if (verify_refname_available_dir(newname, extras, skip,
2639 packed_refs, err) ||
2640 verify_refname_available_dir(newname, extras, skip,
2641 loose_refs, err))
2642 return -1;
2643
2644 return 0;
2645}
2646
7bd9bcf3
MH
2647static int write_ref_to_lockfile(struct ref_lock *lock,
2648 const unsigned char *sha1, struct strbuf *err);
2649static int commit_ref_update(struct ref_lock *lock,
2650 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2651 struct strbuf *err);
7bd9bcf3
MH
2652
2653int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2654{
2655 unsigned char sha1[20], orig_sha1[20];
2656 int flag = 0, logmoved = 0;
2657 struct ref_lock *lock;
2658 struct stat loginfo;
2659 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
7bd9bcf3
MH
2660 struct strbuf err = STRBUF_INIT;
2661
2662 if (log && S_ISLNK(loginfo.st_mode))
2663 return error("reflog for %s is a symlink", oldrefname);
2664
12fd3496
DT
2665 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2666 orig_sha1, &flag))
e711b1af
MH
2667 return error("refname %s not found", oldrefname);
2668
7bd9bcf3
MH
2669 if (flag & REF_ISSYMREF)
2670 return error("refname %s is a symbolic ref, renaming it is not supported",
2671 oldrefname);
7bd9bcf3
MH
2672 if (!rename_ref_available(oldrefname, newrefname))
2673 return 1;
2674
2675 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2676 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2677 oldrefname, strerror(errno));
2678
2679 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2680 error("unable to delete old %s", oldrefname);
2681 goto rollback;
2682 }
2683
12fd3496
DT
2684 /*
2685 * Since we are doing a shallow lookup, sha1 is not the
2686 * correct value to pass to delete_ref as old_sha1. But that
2687 * doesn't matter, because an old_sha1 check wouldn't add to
2688 * the safety anyway; we want to delete the reference whatever
2689 * its current value.
2690 */
2691 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2692 sha1, NULL) &&
2693 delete_ref(newrefname, NULL, REF_NODEREF)) {
7bd9bcf3
MH
2694 if (errno==EISDIR) {
2695 struct strbuf path = STRBUF_INIT;
2696 int result;
2697
2698 strbuf_git_path(&path, "%s", newrefname);
2699 result = remove_empty_directories(&path);
2700 strbuf_release(&path);
2701
2702 if (result) {
2703 error("Directory not empty: %s", newrefname);
2704 goto rollback;
2705 }
2706 } else {
2707 error("unable to delete existing %s", newrefname);
2708 goto rollback;
2709 }
2710 }
2711
2712 if (log && rename_tmp_log(newrefname))
2713 goto rollback;
2714
2715 logmoved = log;
2716
12fd3496
DT
2717 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, REF_NODEREF,
2718 NULL, &err);
7bd9bcf3
MH
2719 if (!lock) {
2720 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2721 strbuf_release(&err);
2722 goto rollback;
2723 }
2724 hashcpy(lock->old_oid.hash, orig_sha1);
2725
2726 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
5d9b2de4 2727 commit_ref_update(lock, orig_sha1, logmsg, &err)) {
7bd9bcf3
MH
2728 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
2729 strbuf_release(&err);
2730 goto rollback;
2731 }
2732
2733 return 0;
2734
2735 rollback:
12fd3496
DT
2736 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, REF_NODEREF,
2737 NULL, &err);
7bd9bcf3
MH
2738 if (!lock) {
2739 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2740 strbuf_release(&err);
2741 goto rollbacklog;
2742 }
2743
2744 flag = log_all_ref_updates;
2745 log_all_ref_updates = 0;
2746 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
5d9b2de4 2747 commit_ref_update(lock, orig_sha1, NULL, &err)) {
7bd9bcf3
MH
2748 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
2749 strbuf_release(&err);
2750 }
2751 log_all_ref_updates = flag;
2752
2753 rollbacklog:
2754 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2755 error("unable to restore logfile %s from %s: %s",
2756 oldrefname, newrefname, strerror(errno));
2757 if (!logmoved && log &&
2758 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2759 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2760 oldrefname, strerror(errno));
2761
2762 return 1;
2763}
2764
2765static int close_ref(struct ref_lock *lock)
2766{
2767 if (close_lock_file(lock->lk))
2768 return -1;
2769 return 0;
2770}
2771
2772static int commit_ref(struct ref_lock *lock)
2773{
5387c0d8
MH
2774 char *path = get_locked_file_path(lock->lk);
2775 struct stat st;
2776
2777 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
2778 /*
2779 * There is a directory at the path we want to rename
2780 * the lockfile to. Hopefully it is empty; try to
2781 * delete it.
2782 */
2783 size_t len = strlen(path);
2784 struct strbuf sb_path = STRBUF_INIT;
2785
2786 strbuf_attach(&sb_path, path, len, len);
2787
2788 /*
2789 * If this fails, commit_lock_file() will also fail
2790 * and will report the problem.
2791 */
2792 remove_empty_directories(&sb_path);
2793 strbuf_release(&sb_path);
2794 } else {
2795 free(path);
2796 }
2797
7bd9bcf3
MH
2798 if (commit_lock_file(lock->lk))
2799 return -1;
2800 return 0;
2801}
2802
2803/*
2804 * Create a reflog for a ref. If force_create = 0, the reflog will
2805 * only be created for certain refs (those for which
2806 * should_autocreate_reflog returns non-zero. Otherwise, create it
2807 * regardless of the ref name. Fill in *err and return -1 on failure.
2808 */
2809static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
2810{
2811 int logfd, oflags = O_APPEND | O_WRONLY;
2812
2813 strbuf_git_path(logfile, "logs/%s", refname);
2814 if (force_create || should_autocreate_reflog(refname)) {
2815 if (safe_create_leading_directories(logfile->buf) < 0) {
0568c8e9 2816 strbuf_addf(err, "unable to create directory for '%s': "
7bd9bcf3
MH
2817 "%s", logfile->buf, strerror(errno));
2818 return -1;
2819 }
2820 oflags |= O_CREAT;
2821 }
2822
2823 logfd = open(logfile->buf, oflags, 0666);
2824 if (logfd < 0) {
2825 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
2826 return 0;
2827
2828 if (errno == EISDIR) {
2829 if (remove_empty_directories(logfile)) {
0568c8e9 2830 strbuf_addf(err, "there are still logs under "
7bd9bcf3
MH
2831 "'%s'", logfile->buf);
2832 return -1;
2833 }
2834 logfd = open(logfile->buf, oflags, 0666);
2835 }
2836
2837 if (logfd < 0) {
0568c8e9 2838 strbuf_addf(err, "unable to append to '%s': %s",
7bd9bcf3
MH
2839 logfile->buf, strerror(errno));
2840 return -1;
2841 }
2842 }
2843
2844 adjust_shared_perm(logfile->buf);
2845 close(logfd);
2846 return 0;
2847}
2848
2849
2850int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)
2851{
2852 int ret;
2853 struct strbuf sb = STRBUF_INIT;
2854
2855 ret = log_ref_setup(refname, &sb, err, force_create);
2856 strbuf_release(&sb);
2857 return ret;
2858}
2859
2860static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2861 const unsigned char *new_sha1,
2862 const char *committer, const char *msg)
2863{
2864 int msglen, written;
2865 unsigned maxlen, len;
2866 char *logrec;
2867
2868 msglen = msg ? strlen(msg) : 0;
2869 maxlen = strlen(committer) + msglen + 100;
2870 logrec = xmalloc(maxlen);
2871 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2872 sha1_to_hex(old_sha1),
2873 sha1_to_hex(new_sha1),
2874 committer);
2875 if (msglen)
2876 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2877
2878 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2879 free(logrec);
2880 if (written != len)
2881 return -1;
2882
2883 return 0;
2884}
2885
2886static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
2887 const unsigned char *new_sha1, const char *msg,
2888 struct strbuf *logfile, int flags,
2889 struct strbuf *err)
2890{
2891 int logfd, result, oflags = O_APPEND | O_WRONLY;
2892
2893 if (log_all_ref_updates < 0)
2894 log_all_ref_updates = !is_bare_repository();
2895
2896 result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
2897
2898 if (result)
2899 return result;
2900
2901 logfd = open(logfile->buf, oflags);
2902 if (logfd < 0)
2903 return 0;
2904 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2905 git_committer_info(0), msg);
2906 if (result) {
0568c8e9 2907 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,
7bd9bcf3
MH
2908 strerror(errno));
2909 close(logfd);
2910 return -1;
2911 }
2912 if (close(logfd)) {
0568c8e9 2913 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,
7bd9bcf3
MH
2914 strerror(errno));
2915 return -1;
2916 }
2917 return 0;
2918}
2919
2920static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2921 const unsigned char *new_sha1, const char *msg,
2922 int flags, struct strbuf *err)
5f3c3a4e
DT
2923{
2924 return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
2925 err);
2926}
2927
2928int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
2929 const unsigned char *new_sha1, const char *msg,
2930 int flags, struct strbuf *err)
7bd9bcf3
MH
2931{
2932 struct strbuf sb = STRBUF_INIT;
2933 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
2934 err);
2935 strbuf_release(&sb);
2936 return ret;
2937}
2938
2939/*
2940 * Write sha1 into the open lockfile, then close the lockfile. On
2941 * errors, rollback the lockfile, fill in *err and
2942 * return -1.
2943 */
2944static int write_ref_to_lockfile(struct ref_lock *lock,
2945 const unsigned char *sha1, struct strbuf *err)
2946{
2947 static char term = '\n';
2948 struct object *o;
2949 int fd;
2950
2951 o = parse_object(sha1);
2952 if (!o) {
2953 strbuf_addf(err,
0568c8e9 2954 "trying to write ref '%s' with nonexistent object %s",
7bd9bcf3
MH
2955 lock->ref_name, sha1_to_hex(sha1));
2956 unlock_ref(lock);
2957 return -1;
2958 }
2959 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2960 strbuf_addf(err,
0568c8e9 2961 "trying to write non-commit object %s to branch '%s'",
7bd9bcf3
MH
2962 sha1_to_hex(sha1), lock->ref_name);
2963 unlock_ref(lock);
2964 return -1;
2965 }
2966 fd = get_lock_file_fd(lock->lk);
2967 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
2968 write_in_full(fd, &term, 1) != 1 ||
2969 close_ref(lock) < 0) {
2970 strbuf_addf(err,
0568c8e9 2971 "couldn't write '%s'", get_lock_file_path(lock->lk));
7bd9bcf3
MH
2972 unlock_ref(lock);
2973 return -1;
2974 }
2975 return 0;
2976}
2977
2978/*
2979 * Commit a change to a loose reference that has already been written
2980 * to the loose reference lockfile. Also update the reflogs if
2981 * necessary, using the specified lockmsg (which can be NULL).
2982 */
2983static int commit_ref_update(struct ref_lock *lock,
2984 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2985 struct strbuf *err)
7bd9bcf3 2986{
00eebe35
MH
2987 struct files_ref_store *refs =
2988 get_files_ref_store(NULL, "commit_ref_update");
2989
2990 clear_loose_ref_cache(refs);
7a418f3a 2991 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, 0, err)) {
7bd9bcf3 2992 char *old_msg = strbuf_detach(err, NULL);
0568c8e9 2993 strbuf_addf(err, "cannot update the ref '%s': %s",
7bd9bcf3
MH
2994 lock->ref_name, old_msg);
2995 free(old_msg);
2996 unlock_ref(lock);
2997 return -1;
2998 }
7a418f3a
MH
2999
3000 if (strcmp(lock->ref_name, "HEAD") != 0) {
7bd9bcf3
MH
3001 /*
3002 * Special hack: If a branch is updated directly and HEAD
3003 * points to it (may happen on the remote side of a push
3004 * for example) then logically the HEAD reflog should be
3005 * updated too.
3006 * A generic solution implies reverse symref information,
3007 * but finding all symrefs pointing to the given branch
3008 * would be rather costly for this rare event (the direct
3009 * update of a branch) to be worth it. So let's cheat and
3010 * check with HEAD only which should cover 99% of all usage
3011 * scenarios (even 100% of the default ones).
3012 */
3013 unsigned char head_sha1[20];
3014 int head_flag;
3015 const char *head_ref;
7a418f3a 3016
7bd9bcf3
MH
3017 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3018 head_sha1, &head_flag);
3019 if (head_ref && (head_flag & REF_ISSYMREF) &&
3020 !strcmp(head_ref, lock->ref_name)) {
3021 struct strbuf log_err = STRBUF_INIT;
3022 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
3023 logmsg, 0, &log_err)) {
3024 error("%s", log_err.buf);
3025 strbuf_release(&log_err);
3026 }
3027 }
3028 }
7a418f3a 3029
5d9b2de4 3030 if (commit_ref(lock)) {
0568c8e9 3031 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
7bd9bcf3
MH
3032 unlock_ref(lock);
3033 return -1;
3034 }
3035
3036 unlock_ref(lock);
3037 return 0;
3038}
3039
370e5ad6 3040static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 3041{
370e5ad6 3042 int ret = -1;
7bd9bcf3 3043#ifndef NO_SYMLINK_HEAD
370e5ad6
JK
3044 char *ref_path = get_locked_file_path(lock->lk);
3045 unlink(ref_path);
3046 ret = symlink(target, ref_path);
3047 free(ref_path);
3048
3049 if (ret)
7bd9bcf3 3050 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 3051#endif
370e5ad6
JK
3052 return ret;
3053}
7bd9bcf3 3054
370e5ad6
JK
3055static void update_symref_reflog(struct ref_lock *lock, const char *refname,
3056 const char *target, const char *logmsg)
3057{
3058 struct strbuf err = STRBUF_INIT;
3059 unsigned char new_sha1[20];
b9badadd 3060 if (logmsg && !read_ref(target, new_sha1) &&
370e5ad6 3061 log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
7bd9bcf3
MH
3062 error("%s", err.buf);
3063 strbuf_release(&err);
3064 }
370e5ad6 3065}
7bd9bcf3 3066
370e5ad6
JK
3067static int create_symref_locked(struct ref_lock *lock, const char *refname,
3068 const char *target, const char *logmsg)
3069{
3070 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
3071 update_symref_reflog(lock, refname, target, logmsg);
3072 return 0;
3073 }
3074
3075 if (!fdopen_lock_file(lock->lk, "w"))
3076 return error("unable to fdopen %s: %s",
3077 lock->lk->tempfile.filename.buf, strerror(errno));
3078
396da8f7
JK
3079 update_symref_reflog(lock, refname, target, logmsg);
3080
370e5ad6
JK
3081 /* no error check; commit_ref will check ferror */
3082 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
3083 if (commit_ref(lock) < 0)
3084 return error("unable to write symref for %s: %s", refname,
3085 strerror(errno));
7bd9bcf3
MH
3086 return 0;
3087}
3088
370e5ad6
JK
3089int create_symref(const char *refname, const char *target, const char *logmsg)
3090{
3091 struct strbuf err = STRBUF_INIT;
3092 struct ref_lock *lock;
3093 int ret;
3094
3095 lock = lock_ref_sha1_basic(refname, NULL, NULL, NULL, REF_NODEREF, NULL,
3096 &err);
3097 if (!lock) {
3098 error("%s", err.buf);
3099 strbuf_release(&err);
3100 return -1;
3101 }
3102
3103 ret = create_symref_locked(lock, refname, target, logmsg);
3104 unlock_ref(lock);
3105 return ret;
3106}
3107
2233066e
KY
3108int set_worktree_head_symref(const char *gitdir, const char *target)
3109{
3110 static struct lock_file head_lock;
3111 struct ref_lock *lock;
2233066e
KY
3112 struct strbuf head_path = STRBUF_INIT;
3113 const char *head_rel;
3114 int ret;
3115
3116 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));
3117 if (hold_lock_file_for_update(&head_lock, head_path.buf,
3118 LOCK_NO_DEREF) < 0) {
18eb3a9c
KY
3119 struct strbuf err = STRBUF_INIT;
3120 unable_to_lock_message(head_path.buf, errno, &err);
2233066e
KY
3121 error("%s", err.buf);
3122 strbuf_release(&err);
3123 strbuf_release(&head_path);
3124 return -1;
3125 }
3126
3127 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for
3128 linked trees */
3129 head_rel = remove_leading_path(head_path.buf,
3130 absolute_path(get_git_common_dir()));
3131 /* to make use of create_symref_locked(), initialize ref_lock */
3132 lock = xcalloc(1, sizeof(struct ref_lock));
3133 lock->lk = &head_lock;
3134 lock->ref_name = xstrdup(head_rel);
2233066e
KY
3135
3136 ret = create_symref_locked(lock, head_rel, target, NULL);
3137
3138 unlock_ref(lock); /* will free lock */
3139 strbuf_release(&head_path);
3140 return ret;
3141}
3142
7bd9bcf3
MH
3143int reflog_exists(const char *refname)
3144{
3145 struct stat st;
3146
3147 return !lstat(git_path("logs/%s", refname), &st) &&
3148 S_ISREG(st.st_mode);
3149}
3150
3151int delete_reflog(const char *refname)
3152{
3153 return remove_path(git_path("logs/%s", refname));
3154}
3155
3156static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3157{
3158 unsigned char osha1[20], nsha1[20];
3159 char *email_end, *message;
3160 unsigned long timestamp;
3161 int tz;
3162
3163 /* old SP new SP name <email> SP time TAB msg LF */
3164 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3165 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3166 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3167 !(email_end = strchr(sb->buf + 82, '>')) ||
3168 email_end[1] != ' ' ||
3169 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3170 !message || message[0] != ' ' ||
3171 (message[1] != '+' && message[1] != '-') ||
3172 !isdigit(message[2]) || !isdigit(message[3]) ||
3173 !isdigit(message[4]) || !isdigit(message[5]))
3174 return 0; /* corrupt? */
3175 email_end[1] = '\0';
3176 tz = strtol(message + 1, NULL, 10);
3177 if (message[6] != '\t')
3178 message += 6;
3179 else
3180 message += 7;
3181 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3182}
3183
3184static char *find_beginning_of_line(char *bob, char *scan)
3185{
3186 while (bob < scan && *(--scan) != '\n')
3187 ; /* keep scanning backwards */
3188 /*
3189 * Return either beginning of the buffer, or LF at the end of
3190 * the previous line.
3191 */
3192 return scan;
3193}
3194
3195int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3196{
3197 struct strbuf sb = STRBUF_INIT;
3198 FILE *logfp;
3199 long pos;
3200 int ret = 0, at_tail = 1;
3201
3202 logfp = fopen(git_path("logs/%s", refname), "r");
3203 if (!logfp)
3204 return -1;
3205
3206 /* Jump to the end */
3207 if (fseek(logfp, 0, SEEK_END) < 0)
3208 return error("cannot seek back reflog for %s: %s",
3209 refname, strerror(errno));
3210 pos = ftell(logfp);
3211 while (!ret && 0 < pos) {
3212 int cnt;
3213 size_t nread;
3214 char buf[BUFSIZ];
3215 char *endp, *scanp;
3216
3217 /* Fill next block from the end */
3218 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3219 if (fseek(logfp, pos - cnt, SEEK_SET))
3220 return error("cannot seek back reflog for %s: %s",
3221 refname, strerror(errno));
3222 nread = fread(buf, cnt, 1, logfp);
3223 if (nread != 1)
3224 return error("cannot read %d bytes from reflog for %s: %s",
3225 cnt, refname, strerror(errno));
3226 pos -= cnt;
3227
3228 scanp = endp = buf + cnt;
3229 if (at_tail && scanp[-1] == '\n')
3230 /* Looking at the final LF at the end of the file */
3231 scanp--;
3232 at_tail = 0;
3233
3234 while (buf < scanp) {
3235 /*
3236 * terminating LF of the previous line, or the beginning
3237 * of the buffer.
3238 */
3239 char *bp;
3240
3241 bp = find_beginning_of_line(buf, scanp);
3242
3243 if (*bp == '\n') {
3244 /*
3245 * The newline is the end of the previous line,
3246 * so we know we have complete line starting
3247 * at (bp + 1). Prefix it onto any prior data
3248 * we collected for the line and process it.
3249 */
3250 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3251 scanp = bp;
3252 endp = bp + 1;
3253 ret = show_one_reflog_ent(&sb, fn, cb_data);
3254 strbuf_reset(&sb);
3255 if (ret)
3256 break;
3257 } else if (!pos) {
3258 /*
3259 * We are at the start of the buffer, and the
3260 * start of the file; there is no previous
3261 * line, and we have everything for this one.
3262 * Process it, and we can end the loop.
3263 */
3264 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3265 ret = show_one_reflog_ent(&sb, fn, cb_data);
3266 strbuf_reset(&sb);
3267 break;
3268 }
3269
3270 if (bp == buf) {
3271 /*
3272 * We are at the start of the buffer, and there
3273 * is more file to read backwards. Which means
3274 * we are in the middle of a line. Note that we
3275 * may get here even if *bp was a newline; that
3276 * just means we are at the exact end of the
3277 * previous line, rather than some spot in the
3278 * middle.
3279 *
3280 * Save away what we have to be combined with
3281 * the data from the next read.
3282 */
3283 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3284 break;
3285 }
3286 }
3287
3288 }
3289 if (!ret && sb.len)
3290 die("BUG: reverse reflog parser had leftover data");
3291
3292 fclose(logfp);
3293 strbuf_release(&sb);
3294 return ret;
3295}
3296
3297int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3298{
3299 FILE *logfp;
3300 struct strbuf sb = STRBUF_INIT;
3301 int ret = 0;
3302
3303 logfp = fopen(git_path("logs/%s", refname), "r");
3304 if (!logfp)
3305 return -1;
3306
3307 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3308 ret = show_one_reflog_ent(&sb, fn, cb_data);
3309 fclose(logfp);
3310 strbuf_release(&sb);
3311 return ret;
3312}
7bd9bcf3 3313
2880d16f
MH
3314struct files_reflog_iterator {
3315 struct ref_iterator base;
7bd9bcf3 3316
2880d16f
MH
3317 struct dir_iterator *dir_iterator;
3318 struct object_id oid;
3319};
7bd9bcf3 3320
2880d16f
MH
3321static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
3322{
3323 struct files_reflog_iterator *iter =
3324 (struct files_reflog_iterator *)ref_iterator;
3325 struct dir_iterator *diter = iter->dir_iterator;
3326 int ok;
3327
3328 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
3329 int flags;
3330
3331 if (!S_ISREG(diter->st.st_mode))
7bd9bcf3 3332 continue;
2880d16f
MH
3333 if (diter->basename[0] == '.')
3334 continue;
3335 if (ends_with(diter->basename, ".lock"))
7bd9bcf3 3336 continue;
7bd9bcf3 3337
2880d16f
MH
3338 if (read_ref_full(diter->relative_path, 0,
3339 iter->oid.hash, &flags)) {
3340 error("bad ref for %s", diter->path.buf);
3341 continue;
7bd9bcf3 3342 }
2880d16f
MH
3343
3344 iter->base.refname = diter->relative_path;
3345 iter->base.oid = &iter->oid;
3346 iter->base.flags = flags;
3347 return ITER_OK;
7bd9bcf3 3348 }
2880d16f
MH
3349
3350 iter->dir_iterator = NULL;
3351 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
3352 ok = ITER_ERROR;
3353 return ok;
3354}
3355
3356static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
3357 struct object_id *peeled)
3358{
3359 die("BUG: ref_iterator_peel() called for reflog_iterator");
3360}
3361
3362static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
3363{
3364 struct files_reflog_iterator *iter =
3365 (struct files_reflog_iterator *)ref_iterator;
3366 int ok = ITER_DONE;
3367
3368 if (iter->dir_iterator)
3369 ok = dir_iterator_abort(iter->dir_iterator);
3370
3371 base_ref_iterator_free(ref_iterator);
3372 return ok;
3373}
3374
3375static struct ref_iterator_vtable files_reflog_iterator_vtable = {
3376 files_reflog_iterator_advance,
3377 files_reflog_iterator_peel,
3378 files_reflog_iterator_abort
3379};
3380
3381struct ref_iterator *files_reflog_iterator_begin(void)
3382{
3383 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
3384 struct ref_iterator *ref_iterator = &iter->base;
3385
3386 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
3387 iter->dir_iterator = dir_iterator_begin(git_path("logs"));
3388 return ref_iterator;
7bd9bcf3
MH
3389}
3390
3391int for_each_reflog(each_ref_fn fn, void *cb_data)
3392{
2880d16f
MH
3393 return do_for_each_ref_iterator(files_reflog_iterator_begin(),
3394 fn, cb_data);
7bd9bcf3
MH
3395}
3396
3397static int ref_update_reject_duplicates(struct string_list *refnames,
3398 struct strbuf *err)
3399{
3400 int i, n = refnames->nr;
3401
3402 assert(err);
3403
3404 for (i = 1; i < n; i++)
3405 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3406 strbuf_addf(err,
0568c8e9 3407 "multiple updates for ref '%s' not allowed.",
7bd9bcf3
MH
3408 refnames->items[i].string);
3409 return 1;
3410 }
3411 return 0;
3412}
3413
165056b2 3414/*
92b1551b
MH
3415 * If update is a direct update of head_ref (the reference pointed to
3416 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
3417 */
3418static int split_head_update(struct ref_update *update,
3419 struct ref_transaction *transaction,
3420 const char *head_ref,
3421 struct string_list *affected_refnames,
3422 struct strbuf *err)
3423{
3424 struct string_list_item *item;
3425 struct ref_update *new_update;
3426
3427 if ((update->flags & REF_LOG_ONLY) ||
3428 (update->flags & REF_ISPRUNING) ||
3429 (update->flags & REF_UPDATE_VIA_HEAD))
3430 return 0;
3431
3432 if (strcmp(update->refname, head_ref))
3433 return 0;
3434
3435 /*
3436 * First make sure that HEAD is not already in the
3437 * transaction. This insertion is O(N) in the transaction
3438 * size, but it happens at most once per transaction.
3439 */
3440 item = string_list_insert(affected_refnames, "HEAD");
3441 if (item->util) {
3442 /* An entry already existed */
3443 strbuf_addf(err,
3444 "multiple updates for 'HEAD' (including one "
3445 "via its referent '%s') are not allowed",
3446 update->refname);
3447 return TRANSACTION_NAME_CONFLICT;
3448 }
3449
3450 new_update = ref_transaction_add_update(
3451 transaction, "HEAD",
3452 update->flags | REF_LOG_ONLY | REF_NODEREF,
3453 update->new_sha1, update->old_sha1,
3454 update->msg);
3455
3456 item->util = new_update;
3457
3458 return 0;
3459}
3460
3461/*
3462 * update is for a symref that points at referent and doesn't have
3463 * REF_NODEREF set. Split it into two updates:
3464 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
3465 * - A new, separate update for the referent reference
3466 * Note that the new update will itself be subject to splitting when
3467 * the iteration gets to it.
3468 */
3469static int split_symref_update(struct ref_update *update,
3470 const char *referent,
3471 struct ref_transaction *transaction,
3472 struct string_list *affected_refnames,
3473 struct strbuf *err)
3474{
3475 struct string_list_item *item;
3476 struct ref_update *new_update;
3477 unsigned int new_flags;
3478
3479 /*
3480 * First make sure that referent is not already in the
3481 * transaction. This insertion is O(N) in the transaction
3482 * size, but it happens at most once per symref in a
3483 * transaction.
3484 */
3485 item = string_list_insert(affected_refnames, referent);
3486 if (item->util) {
3487 /* An entry already existed */
3488 strbuf_addf(err,
3489 "multiple updates for '%s' (including one "
3490 "via symref '%s') are not allowed",
3491 referent, update->refname);
3492 return TRANSACTION_NAME_CONFLICT;
3493 }
3494
3495 new_flags = update->flags;
3496 if (!strcmp(update->refname, "HEAD")) {
3497 /*
3498 * Record that the new update came via HEAD, so that
3499 * when we process it, split_head_update() doesn't try
3500 * to add another reflog update for HEAD. Note that
3501 * this bit will be propagated if the new_update
3502 * itself needs to be split.
3503 */
3504 new_flags |= REF_UPDATE_VIA_HEAD;
3505 }
3506
3507 new_update = ref_transaction_add_update(
3508 transaction, referent, new_flags,
3509 update->new_sha1, update->old_sha1,
3510 update->msg);
3511
6e30b2f6
MH
3512 new_update->parent_update = update;
3513
3514 /*
3515 * Change the symbolic ref update to log only. Also, it
3516 * doesn't need to check its old SHA-1 value, as that will be
3517 * done when new_update is processed.
3518 */
92b1551b 3519 update->flags |= REF_LOG_ONLY | REF_NODEREF;
6e30b2f6 3520 update->flags &= ~REF_HAVE_OLD;
92b1551b
MH
3521
3522 item->util = new_update;
3523
3524 return 0;
3525}
3526
6e30b2f6
MH
3527/*
3528 * Return the refname under which update was originally requested.
3529 */
3530static const char *original_update_refname(struct ref_update *update)
3531{
3532 while (update->parent_update)
3533 update = update->parent_update;
3534
3535 return update->refname;
3536}
3537
92b1551b
MH
3538/*
3539 * Prepare for carrying out update:
3540 * - Lock the reference referred to by update.
3541 * - Read the reference under lock.
3542 * - Check that its old SHA-1 value (if specified) is correct, and in
3543 * any case record it in update->lock->old_oid for later use when
3544 * writing the reflog.
3545 * - If it is a symref update without REF_NODEREF, split it up into a
3546 * REF_LOG_ONLY update of the symref and add a separate update for
3547 * the referent to transaction.
3548 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
3549 * update of HEAD.
165056b2
MH
3550 */
3551static int lock_ref_for_update(struct ref_update *update,
3552 struct ref_transaction *transaction,
92b1551b 3553 const char *head_ref,
165056b2
MH
3554 struct string_list *affected_refnames,
3555 struct strbuf *err)
3556{
92b1551b
MH
3557 struct strbuf referent = STRBUF_INIT;
3558 int mustexist = (update->flags & REF_HAVE_OLD) &&
3559 !is_null_sha1(update->old_sha1);
165056b2 3560 int ret;
92b1551b 3561 struct ref_lock *lock;
165056b2 3562
92b1551b 3563 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
165056b2 3564 update->flags |= REF_DELETING;
92b1551b
MH
3565
3566 if (head_ref) {
3567 ret = split_head_update(update, transaction, head_ref,
3568 affected_refnames, err);
3569 if (ret)
3570 return ret;
3571 }
3572
3573 ret = lock_raw_ref(update->refname, mustexist,
3574 affected_refnames, NULL,
3575 &update->lock, &referent,
3576 &update->type, err);
3577
3578 if (ret) {
165056b2
MH
3579 char *reason;
3580
165056b2
MH
3581 reason = strbuf_detach(err, NULL);
3582 strbuf_addf(err, "cannot lock ref '%s': %s",
3583 update->refname, reason);
3584 free(reason);
3585 return ret;
3586 }
92b1551b
MH
3587
3588 lock = update->lock;
3589
8169d0d0 3590 if (update->type & REF_ISSYMREF) {
6e30b2f6
MH
3591 if (update->flags & REF_NODEREF) {
3592 /*
3593 * We won't be reading the referent as part of
3594 * the transaction, so we have to read it here
3595 * to record and possibly check old_sha1:
3596 */
3597 if (read_ref_full(update->refname,
3598 mustexist ? RESOLVE_REF_READING : 0,
3599 lock->old_oid.hash, NULL)) {
3600 if (update->flags & REF_HAVE_OLD) {
3601 strbuf_addf(err, "cannot lock ref '%s': "
3602 "can't resolve old value",
3603 update->refname);
3604 return TRANSACTION_GENERIC_ERROR;
3605 } else {
3606 hashclr(lock->old_oid.hash);
3607 }
3608 }
3609 if ((update->flags & REF_HAVE_OLD) &&
3610 hashcmp(lock->old_oid.hash, update->old_sha1)) {
3611 strbuf_addf(err, "cannot lock ref '%s': "
3612 "is at %s but expected %s",
3613 update->refname,
3614 sha1_to_hex(lock->old_oid.hash),
3615 sha1_to_hex(update->old_sha1));
8169d0d0 3616 return TRANSACTION_GENERIC_ERROR;
8169d0d0 3617 }
92b1551b 3618
6e30b2f6
MH
3619 } else {
3620 /*
3621 * Create a new update for the reference this
3622 * symref is pointing at. Also, we will record
3623 * and verify old_sha1 for this update as part
3624 * of processing the split-off update, so we
3625 * don't have to do it here.
3626 */
92b1551b
MH
3627 ret = split_symref_update(update, referent.buf, transaction,
3628 affected_refnames, err);
3629 if (ret)
3630 return ret;
3631 }
6e30b2f6
MH
3632 } else {
3633 struct ref_update *parent_update;
8169d0d0 3634
6e30b2f6
MH
3635 /*
3636 * If this update is happening indirectly because of a
3637 * symref update, record the old SHA-1 in the parent
3638 * update:
3639 */
3640 for (parent_update = update->parent_update;
3641 parent_update;
3642 parent_update = parent_update->parent_update) {
3643 oidcpy(&parent_update->lock->old_oid, &lock->old_oid);
3644 }
3645
3646 if ((update->flags & REF_HAVE_OLD) &&
3647 hashcmp(lock->old_oid.hash, update->old_sha1)) {
3648 if (is_null_sha1(update->old_sha1))
3649 strbuf_addf(err, "cannot lock ref '%s': reference already exists",
3650 original_update_refname(update));
3651 else
3652 strbuf_addf(err, "cannot lock ref '%s': is at %s but expected %s",
3653 original_update_refname(update),
3654 sha1_to_hex(lock->old_oid.hash),
3655 sha1_to_hex(update->old_sha1));
3656
3657 return TRANSACTION_GENERIC_ERROR;
3658 }
92b1551b
MH
3659 }
3660
165056b2
MH
3661 if ((update->flags & REF_HAVE_NEW) &&
3662 !(update->flags & REF_DELETING) &&
3663 !(update->flags & REF_LOG_ONLY)) {
92b1551b
MH
3664 if (!(update->type & REF_ISSYMREF) &&
3665 !hashcmp(lock->old_oid.hash, update->new_sha1)) {
165056b2
MH
3666 /*
3667 * The reference already has the desired
3668 * value, so we don't need to write it.
3669 */
92b1551b 3670 } else if (write_ref_to_lockfile(lock, update->new_sha1,
165056b2
MH
3671 err)) {
3672 char *write_err = strbuf_detach(err, NULL);
3673
3674 /*
3675 * The lock was freed upon failure of
3676 * write_ref_to_lockfile():
3677 */
3678 update->lock = NULL;
3679 strbuf_addf(err,
3680 "cannot update the ref '%s': %s",
3681 update->refname, write_err);
3682 free(write_err);
3683 return TRANSACTION_GENERIC_ERROR;
3684 } else {
3685 update->flags |= REF_NEEDS_COMMIT;
3686 }
3687 }
3688 if (!(update->flags & REF_NEEDS_COMMIT)) {
3689 /*
3690 * We didn't call write_ref_to_lockfile(), so
3691 * the lockfile is still open. Close it to
3692 * free up the file descriptor:
3693 */
92b1551b 3694 if (close_ref(lock)) {
165056b2
MH
3695 strbuf_addf(err, "couldn't close '%s.lock'",
3696 update->refname);
3697 return TRANSACTION_GENERIC_ERROR;
3698 }
3699 }
3700 return 0;
3701}
3702
7bd9bcf3
MH
3703int ref_transaction_commit(struct ref_transaction *transaction,
3704 struct strbuf *err)
3705{
00eebe35
MH
3706 struct files_ref_store *refs =
3707 get_files_ref_store(NULL, "ref_transaction_commit");
7bd9bcf3 3708 int ret = 0, i;
7bd9bcf3
MH
3709 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3710 struct string_list_item *ref_to_delete;
3711 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
92b1551b
MH
3712 char *head_ref = NULL;
3713 int head_type;
3714 struct object_id head_oid;
7bd9bcf3
MH
3715
3716 assert(err);
3717
3718 if (transaction->state != REF_TRANSACTION_OPEN)
3719 die("BUG: commit called for transaction that is not open");
3720
efe47281 3721 if (!transaction->nr) {
7bd9bcf3
MH
3722 transaction->state = REF_TRANSACTION_CLOSED;
3723 return 0;
3724 }
3725
92b1551b
MH
3726 /*
3727 * Fail if a refname appears more than once in the
3728 * transaction. (If we end up splitting up any updates using
3729 * split_symref_update() or split_head_update(), those
3730 * functions will check that the new updates don't have the
3731 * same refname as any existing ones.)
3732 */
3733 for (i = 0; i < transaction->nr; i++) {
3734 struct ref_update *update = transaction->updates[i];
3735 struct string_list_item *item =
3736 string_list_append(&affected_refnames, update->refname);
3737
3738 /*
3739 * We store a pointer to update in item->util, but at
3740 * the moment we never use the value of this field
3741 * except to check whether it is non-NULL.
3742 */
3743 item->util = update;
3744 }
7bd9bcf3
MH
3745 string_list_sort(&affected_refnames);
3746 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3747 ret = TRANSACTION_GENERIC_ERROR;
3748 goto cleanup;
3749 }
3750
92b1551b
MH
3751 /*
3752 * Special hack: If a branch is updated directly and HEAD
3753 * points to it (may happen on the remote side of a push
3754 * for example) then logically the HEAD reflog should be
3755 * updated too.
3756 *
3757 * A generic solution would require reverse symref lookups,
3758 * but finding all symrefs pointing to a given branch would be
3759 * rather costly for this rare event (the direct update of a
3760 * branch) to be worth it. So let's cheat and check with HEAD
3761 * only, which should cover 99% of all usage scenarios (even
3762 * 100% of the default ones).
3763 *
3764 * So if HEAD is a symbolic reference, then record the name of
3765 * the reference that it points to. If we see an update of
3766 * head_ref within the transaction, then split_head_update()
3767 * arranges for the reflog of HEAD to be updated, too.
3768 */
3769 head_ref = resolve_refdup("HEAD", RESOLVE_REF_NO_RECURSE,
3770 head_oid.hash, &head_type);
3771
3772 if (head_ref && !(head_type & REF_ISSYMREF)) {
3773 free(head_ref);
3774 head_ref = NULL;
3775 }
3776
7bd9bcf3
MH
3777 /*
3778 * Acquire all locks, verify old values if provided, check
3779 * that new values are valid, and write new values to the
3780 * lockfiles, ready to be activated. Only keep one lockfile
3781 * open at a time to avoid running out of file descriptors.
3782 */
efe47281
MH
3783 for (i = 0; i < transaction->nr; i++) {
3784 struct ref_update *update = transaction->updates[i];
7bd9bcf3 3785
92b1551b 3786 ret = lock_ref_for_update(update, transaction, head_ref,
165056b2
MH
3787 &affected_refnames, err);
3788 if (ret)
7bd9bcf3 3789 goto cleanup;
7bd9bcf3
MH
3790 }
3791
3792 /* Perform updates first so live commits remain referenced */
efe47281
MH
3793 for (i = 0; i < transaction->nr; i++) {
3794 struct ref_update *update = transaction->updates[i];
92b1551b 3795 struct ref_lock *lock = update->lock;
7bd9bcf3 3796
d99aa884
DT
3797 if (update->flags & REF_NEEDS_COMMIT ||
3798 update->flags & REF_LOG_ONLY) {
92b1551b
MH
3799 if (log_ref_write(lock->ref_name, lock->old_oid.hash,
3800 update->new_sha1,
3801 update->msg, update->flags, err)) {
3802 char *old_msg = strbuf_detach(err, NULL);
3803
3804 strbuf_addf(err, "cannot update the ref '%s': %s",
3805 lock->ref_name, old_msg);
3806 free(old_msg);
3807 unlock_ref(lock);
7bd9bcf3
MH
3808 update->lock = NULL;
3809 ret = TRANSACTION_GENERIC_ERROR;
3810 goto cleanup;
92b1551b
MH
3811 }
3812 }
3813 if (update->flags & REF_NEEDS_COMMIT) {
00eebe35 3814 clear_loose_ref_cache(refs);
92b1551b
MH
3815 if (commit_ref(lock)) {
3816 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
3817 unlock_ref(lock);
7bd9bcf3 3818 update->lock = NULL;
92b1551b
MH
3819 ret = TRANSACTION_GENERIC_ERROR;
3820 goto cleanup;
7bd9bcf3
MH
3821 }
3822 }
3823 }
7bd9bcf3 3824 /* Perform deletes now that updates are safely completed */
efe47281
MH
3825 for (i = 0; i < transaction->nr; i++) {
3826 struct ref_update *update = transaction->updates[i];
7bd9bcf3 3827
d99aa884
DT
3828 if (update->flags & REF_DELETING &&
3829 !(update->flags & REF_LOG_ONLY)) {
7bd9bcf3
MH
3830 if (delete_ref_loose(update->lock, update->type, err)) {
3831 ret = TRANSACTION_GENERIC_ERROR;
3832 goto cleanup;
3833 }
3834
3835 if (!(update->flags & REF_ISPRUNING))
3836 string_list_append(&refs_to_delete,
3837 update->lock->ref_name);
3838 }
3839 }
3840
3841 if (repack_without_refs(&refs_to_delete, err)) {
3842 ret = TRANSACTION_GENERIC_ERROR;
3843 goto cleanup;
3844 }
3845 for_each_string_list_item(ref_to_delete, &refs_to_delete)
3846 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
00eebe35 3847 clear_loose_ref_cache(refs);
7bd9bcf3
MH
3848
3849cleanup:
3850 transaction->state = REF_TRANSACTION_CLOSED;
3851
efe47281
MH
3852 for (i = 0; i < transaction->nr; i++)
3853 if (transaction->updates[i]->lock)
3854 unlock_ref(transaction->updates[i]->lock);
7bd9bcf3 3855 string_list_clear(&refs_to_delete, 0);
92b1551b 3856 free(head_ref);
7bd9bcf3 3857 string_list_clear(&affected_refnames, 0);
92b1551b 3858
7bd9bcf3
MH
3859 return ret;
3860}
3861
3862static int ref_present(const char *refname,
3863 const struct object_id *oid, int flags, void *cb_data)
3864{
3865 struct string_list *affected_refnames = cb_data;
3866
3867 return string_list_has_string(affected_refnames, refname);
3868}
3869
3870int initial_ref_transaction_commit(struct ref_transaction *transaction,
3871 struct strbuf *err)
3872{
d99825ab
MH
3873 struct files_ref_store *refs =
3874 get_files_ref_store(NULL, "initial_ref_transaction_commit");
7bd9bcf3 3875 int ret = 0, i;
7bd9bcf3
MH
3876 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;