refs: add method to rename refs
[git/git.git] / refs / files-backend.c
CommitLineData
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1#include "../cache.h"
2#include "../refs.h"
3#include "refs-internal.h"
3bc581b9 4#include "../iterator.h"
2880d16f 5#include "../dir-iterator.h"
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6#include "../lockfile.h"
7#include "../object.h"
8#include "../dir.h"
9
10struct ref_lock {
11 char *ref_name;
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12 struct lock_file *lk;
13 struct object_id old_oid;
14};
15
16struct ref_entry;
17
18/*
19 * Information used (along with the information in ref_entry) to
20 * describe a single cached reference. This data structure only
21 * occurs embedded in a union in struct ref_entry, and only when
22 * (ref_entry->flag & REF_DIR) is zero.
23 */
24struct ref_value {
25 /*
26 * The name of the object to which this reference resolves
27 * (which may be a tag object). If REF_ISBROKEN, this is
28 * null. If REF_ISSYMREF, then this is the name of the object
29 * referred to by the last reference in the symlink chain.
30 */
31 struct object_id oid;
32
33 /*
34 * If REF_KNOWS_PEELED, then this field holds the peeled value
35 * of this reference, or null if the reference is known not to
36 * be peelable. See the documentation for peel_ref() for an
37 * exact definition of "peelable".
38 */
39 struct object_id peeled;
40};
41
65a0a8e5 42struct files_ref_store;
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43
44/*
45 * Information used (along with the information in ref_entry) to
46 * describe a level in the hierarchy of references. This data
47 * structure only occurs embedded in a union in struct ref_entry, and
48 * only when (ref_entry.flag & REF_DIR) is set. In that case,
49 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
50 * in the directory have already been read:
51 *
52 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
53 * or packed references, already read.
54 *
55 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
56 * references that hasn't been read yet (nor has any of its
57 * subdirectories).
58 *
59 * Entries within a directory are stored within a growable array of
60 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
61 * sorted are sorted by their component name in strcmp() order and the
62 * remaining entries are unsorted.
63 *
64 * Loose references are read lazily, one directory at a time. When a
65 * directory of loose references is read, then all of the references
66 * in that directory are stored, and REF_INCOMPLETE stubs are created
67 * for any subdirectories, but the subdirectories themselves are not
68 * read. The reading is triggered by get_ref_dir().
69 */
70struct ref_dir {
71 int nr, alloc;
72
73 /*
74 * Entries with index 0 <= i < sorted are sorted by name. New
75 * entries are appended to the list unsorted, and are sorted
76 * only when required; thus we avoid the need to sort the list
77 * after the addition of every reference.
78 */
79 int sorted;
80
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81 /* A pointer to the files_ref_store that contains this ref_dir. */
82 struct files_ref_store *ref_store;
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83
84 struct ref_entry **entries;
85};
86
87/*
88 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
89 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
90 * public values; see refs.h.
91 */
92
93/*
94 * The field ref_entry->u.value.peeled of this value entry contains
95 * the correct peeled value for the reference, which might be
96 * null_sha1 if the reference is not a tag or if it is broken.
97 */
98#define REF_KNOWS_PEELED 0x10
99
100/* ref_entry represents a directory of references */
101#define REF_DIR 0x20
102
103/*
104 * Entry has not yet been read from disk (used only for REF_DIR
105 * entries representing loose references)
106 */
107#define REF_INCOMPLETE 0x40
108
109/*
110 * A ref_entry represents either a reference or a "subdirectory" of
111 * references.
112 *
113 * Each directory in the reference namespace is represented by a
114 * ref_entry with (flags & REF_DIR) set and containing a subdir member
115 * that holds the entries in that directory that have been read so
116 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
117 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
118 * used for loose reference directories.
119 *
120 * References are represented by a ref_entry with (flags & REF_DIR)
121 * unset and a value member that describes the reference's value. The
122 * flag member is at the ref_entry level, but it is also needed to
123 * interpret the contents of the value field (in other words, a
124 * ref_value object is not very much use without the enclosing
125 * ref_entry).
126 *
127 * Reference names cannot end with slash and directories' names are
128 * always stored with a trailing slash (except for the top-level
129 * directory, which is always denoted by ""). This has two nice
130 * consequences: (1) when the entries in each subdir are sorted
131 * lexicographically by name (as they usually are), the references in
132 * a whole tree can be generated in lexicographic order by traversing
133 * the tree in left-to-right, depth-first order; (2) the names of
134 * references and subdirectories cannot conflict, and therefore the
135 * presence of an empty subdirectory does not block the creation of a
136 * similarly-named reference. (The fact that reference names with the
137 * same leading components can conflict *with each other* is a
138 * separate issue that is regulated by verify_refname_available().)
139 *
140 * Please note that the name field contains the fully-qualified
141 * reference (or subdirectory) name. Space could be saved by only
142 * storing the relative names. But that would require the full names
143 * to be generated on the fly when iterating in do_for_each_ref(), and
144 * would break callback functions, who have always been able to assume
145 * that the name strings that they are passed will not be freed during
146 * the iteration.
147 */
148struct ref_entry {
149 unsigned char flag; /* ISSYMREF? ISPACKED? */
150 union {
151 struct ref_value value; /* if not (flags&REF_DIR) */
152 struct ref_dir subdir; /* if (flags&REF_DIR) */
153 } u;
154 /*
155 * The full name of the reference (e.g., "refs/heads/master")
156 * or the full name of the directory with a trailing slash
157 * (e.g., "refs/heads/"):
158 */
159 char name[FLEX_ARRAY];
160};
161
162static void read_loose_refs(const char *dirname, struct ref_dir *dir);
163static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len);
65a0a8e5 164static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
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165 const char *dirname, size_t len,
166 int incomplete);
167static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
168
169static struct ref_dir *get_ref_dir(struct ref_entry *entry)
170{
171 struct ref_dir *dir;
172 assert(entry->flag & REF_DIR);
173 dir = &entry->u.subdir;
174 if (entry->flag & REF_INCOMPLETE) {
175 read_loose_refs(entry->name, dir);
176
177 /*
178 * Manually add refs/bisect, which, being
179 * per-worktree, might not appear in the directory
180 * listing for refs/ in the main repo.
181 */
182 if (!strcmp(entry->name, "refs/")) {
183 int pos = search_ref_dir(dir, "refs/bisect/", 12);
184 if (pos < 0) {
185 struct ref_entry *child_entry;
65a0a8e5 186 child_entry = create_dir_entry(dir->ref_store,
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187 "refs/bisect/",
188 12, 1);
189 add_entry_to_dir(dir, child_entry);
190 read_loose_refs("refs/bisect",
191 &child_entry->u.subdir);
192 }
193 }
194 entry->flag &= ~REF_INCOMPLETE;
195 }
196 return dir;
197}
198
199static struct ref_entry *create_ref_entry(const char *refname,
200 const unsigned char *sha1, int flag,
201 int check_name)
202{
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203 struct ref_entry *ref;
204
205 if (check_name &&
206 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
207 die("Reference has invalid format: '%s'", refname);
96ffc06f 208 FLEX_ALLOC_STR(ref, name, refname);
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209 hashcpy(ref->u.value.oid.hash, sha1);
210 oidclr(&ref->u.value.peeled);
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211 ref->flag = flag;
212 return ref;
213}
214
215static void clear_ref_dir(struct ref_dir *dir);
216
217static void free_ref_entry(struct ref_entry *entry)
218{
219 if (entry->flag & REF_DIR) {
220 /*
221 * Do not use get_ref_dir() here, as that might
222 * trigger the reading of loose refs.
223 */
224 clear_ref_dir(&entry->u.subdir);
225 }
226 free(entry);
227}
228
229/*
230 * Add a ref_entry to the end of dir (unsorted). Entry is always
231 * stored directly in dir; no recursion into subdirectories is
232 * done.
233 */
234static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
235{
236 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
237 dir->entries[dir->nr++] = entry;
238 /* optimize for the case that entries are added in order */
239 if (dir->nr == 1 ||
240 (dir->nr == dir->sorted + 1 &&
241 strcmp(dir->entries[dir->nr - 2]->name,
242 dir->entries[dir->nr - 1]->name) < 0))
243 dir->sorted = dir->nr;
244}
245
246/*
247 * Clear and free all entries in dir, recursively.
248 */
249static void clear_ref_dir(struct ref_dir *dir)
250{
251 int i;
252 for (i = 0; i < dir->nr; i++)
253 free_ref_entry(dir->entries[i]);
254 free(dir->entries);
255 dir->sorted = dir->nr = dir->alloc = 0;
256 dir->entries = NULL;
257}
258
259/*
260 * Create a struct ref_entry object for the specified dirname.
261 * dirname is the name of the directory with a trailing slash (e.g.,
262 * "refs/heads/") or "" for the top-level directory.
263 */
65a0a8e5 264static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
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265 const char *dirname, size_t len,
266 int incomplete)
267{
268 struct ref_entry *direntry;
96ffc06f 269 FLEX_ALLOC_MEM(direntry, name, dirname, len);
65a0a8e5 270 direntry->u.subdir.ref_store = ref_store;
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271 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
272 return direntry;
273}
274
275static int ref_entry_cmp(const void *a, const void *b)
276{
277 struct ref_entry *one = *(struct ref_entry **)a;
278 struct ref_entry *two = *(struct ref_entry **)b;
279 return strcmp(one->name, two->name);
280}
281
282static void sort_ref_dir(struct ref_dir *dir);
283
284struct string_slice {
285 size_t len;
286 const char *str;
287};
288
289static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
290{
291 const struct string_slice *key = key_;
292 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
293 int cmp = strncmp(key->str, ent->name, key->len);
294 if (cmp)
295 return cmp;
296 return '\0' - (unsigned char)ent->name[key->len];
297}
298
299/*
300 * Return the index of the entry with the given refname from the
301 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
302 * no such entry is found. dir must already be complete.
303 */
304static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
305{
306 struct ref_entry **r;
307 struct string_slice key;
308
309 if (refname == NULL || !dir->nr)
310 return -1;
311
312 sort_ref_dir(dir);
313 key.len = len;
314 key.str = refname;
315 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
316 ref_entry_cmp_sslice);
317
318 if (r == NULL)
319 return -1;
320
321 return r - dir->entries;
322}
323
324/*
325 * Search for a directory entry directly within dir (without
326 * recursing). Sort dir if necessary. subdirname must be a directory
327 * name (i.e., end in '/'). If mkdir is set, then create the
328 * directory if it is missing; otherwise, return NULL if the desired
329 * directory cannot be found. dir must already be complete.
330 */
331static struct ref_dir *search_for_subdir(struct ref_dir *dir,
332 const char *subdirname, size_t len,
333 int mkdir)
334{
335 int entry_index = search_ref_dir(dir, subdirname, len);
336 struct ref_entry *entry;
337 if (entry_index == -1) {
338 if (!mkdir)
339 return NULL;
340 /*
341 * Since dir is complete, the absence of a subdir
342 * means that the subdir really doesn't exist;
343 * therefore, create an empty record for it but mark
344 * the record complete.
345 */
65a0a8e5 346 entry = create_dir_entry(dir->ref_store, subdirname, len, 0);
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347 add_entry_to_dir(dir, entry);
348 } else {
349 entry = dir->entries[entry_index];
350 }
351 return get_ref_dir(entry);
352}
353
354/*
355 * If refname is a reference name, find the ref_dir within the dir
356 * tree that should hold refname. If refname is a directory name
357 * (i.e., ends in '/'), then return that ref_dir itself. dir must
358 * represent the top-level directory and must already be complete.
359 * Sort ref_dirs and recurse into subdirectories as necessary. If
360 * mkdir is set, then create any missing directories; otherwise,
361 * return NULL if the desired directory cannot be found.
362 */
363static struct ref_dir *find_containing_dir(struct ref_dir *dir,
364 const char *refname, int mkdir)
365{
366 const char *slash;
367 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
368 size_t dirnamelen = slash - refname + 1;
369 struct ref_dir *subdir;
370 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
371 if (!subdir) {
372 dir = NULL;
373 break;
374 }
375 dir = subdir;
376 }
377
378 return dir;
379}
380
381/*
382 * Find the value entry with the given name in dir, sorting ref_dirs
383 * and recursing into subdirectories as necessary. If the name is not
384 * found or it corresponds to a directory entry, return NULL.
385 */
386static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
387{
388 int entry_index;
389 struct ref_entry *entry;
390 dir = find_containing_dir(dir, refname, 0);
391 if (!dir)
392 return NULL;
393 entry_index = search_ref_dir(dir, refname, strlen(refname));
394 if (entry_index == -1)
395 return NULL;
396 entry = dir->entries[entry_index];
397 return (entry->flag & REF_DIR) ? NULL : entry;
398}
399
400/*
401 * Remove the entry with the given name from dir, recursing into
402 * subdirectories as necessary. If refname is the name of a directory
403 * (i.e., ends with '/'), then remove the directory and its contents.
404 * If the removal was successful, return the number of entries
405 * remaining in the directory entry that contained the deleted entry.
406 * If the name was not found, return -1. Please note that this
407 * function only deletes the entry from the cache; it does not delete
408 * it from the filesystem or ensure that other cache entries (which
409 * might be symbolic references to the removed entry) are updated.
410 * Nor does it remove any containing dir entries that might be made
411 * empty by the removal. dir must represent the top-level directory
412 * and must already be complete.
413 */
414static int remove_entry(struct ref_dir *dir, const char *refname)
415{
416 int refname_len = strlen(refname);
417 int entry_index;
418 struct ref_entry *entry;
419 int is_dir = refname[refname_len - 1] == '/';
420 if (is_dir) {
421 /*
422 * refname represents a reference directory. Remove
423 * the trailing slash; otherwise we will get the
424 * directory *representing* refname rather than the
425 * one *containing* it.
426 */
427 char *dirname = xmemdupz(refname, refname_len - 1);
428 dir = find_containing_dir(dir, dirname, 0);
429 free(dirname);
430 } else {
431 dir = find_containing_dir(dir, refname, 0);
432 }
433 if (!dir)
434 return -1;
435 entry_index = search_ref_dir(dir, refname, refname_len);
436 if (entry_index == -1)
437 return -1;
438 entry = dir->entries[entry_index];
439
440 memmove(&dir->entries[entry_index],
441 &dir->entries[entry_index + 1],
442 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
443 );
444 dir->nr--;
445 if (dir->sorted > entry_index)
446 dir->sorted--;
447 free_ref_entry(entry);
448 return dir->nr;
449}
450
451/*
452 * Add a ref_entry to the ref_dir (unsorted), recursing into
453 * subdirectories as necessary. dir must represent the top-level
454 * directory. Return 0 on success.
455 */
456static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
457{
458 dir = find_containing_dir(dir, ref->name, 1);
459 if (!dir)
460 return -1;
461 add_entry_to_dir(dir, ref);
462 return 0;
463}
464
465/*
466 * Emit a warning and return true iff ref1 and ref2 have the same name
467 * and the same sha1. Die if they have the same name but different
468 * sha1s.
469 */
470static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
471{
472 if (strcmp(ref1->name, ref2->name))
473 return 0;
474
475 /* Duplicate name; make sure that they don't conflict: */
476
477 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
478 /* This is impossible by construction */
479 die("Reference directory conflict: %s", ref1->name);
480
481 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
482 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
483
484 warning("Duplicated ref: %s", ref1->name);
485 return 1;
486}
487
488/*
489 * Sort the entries in dir non-recursively (if they are not already
490 * sorted) and remove any duplicate entries.
491 */
492static void sort_ref_dir(struct ref_dir *dir)
493{
494 int i, j;
495 struct ref_entry *last = NULL;
496
497 /*
498 * This check also prevents passing a zero-length array to qsort(),
499 * which is a problem on some platforms.
500 */
501 if (dir->sorted == dir->nr)
502 return;
503
504 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
505
506 /* Remove any duplicates: */
507 for (i = 0, j = 0; j < dir->nr; j++) {
508 struct ref_entry *entry = dir->entries[j];
509 if (last && is_dup_ref(last, entry))
510 free_ref_entry(entry);
511 else
512 last = dir->entries[i++] = entry;
513 }
514 dir->sorted = dir->nr = i;
515}
516
7bd9bcf3 517/*
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518 * Return true if refname, which has the specified oid and flags, can
519 * be resolved to an object in the database. If the referred-to object
520 * does not exist, emit a warning and return false.
7bd9bcf3 521 */
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522static int ref_resolves_to_object(const char *refname,
523 const struct object_id *oid,
524 unsigned int flags)
7bd9bcf3 525{
a8739244 526 if (flags & REF_ISBROKEN)
7bd9bcf3 527 return 0;
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528 if (!has_sha1_file(oid->hash)) {
529 error("%s does not point to a valid object!", refname);
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530 return 0;
531 }
532 return 1;
533}
534
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535/*
536 * Return true if the reference described by entry can be resolved to
537 * an object in the database; otherwise, emit a warning and return
538 * false.
539 */
540static int entry_resolves_to_object(struct ref_entry *entry)
541{
542 return ref_resolves_to_object(entry->name,
543 &entry->u.value.oid, entry->flag);
544}
545
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546typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
547
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548/*
549 * Call fn for each reference in dir that has index in the range
550 * offset <= index < dir->nr. Recurse into subdirectories that are in
551 * that index range, sorting them before iterating. This function
552 * does not sort dir itself; it should be sorted beforehand. fn is
553 * called for all references, including broken ones.
554 */
555static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
556 each_ref_entry_fn fn, void *cb_data)
557{
558 int i;
559 assert(dir->sorted == dir->nr);
560 for (i = offset; i < dir->nr; i++) {
561 struct ref_entry *entry = dir->entries[i];
562 int retval;
563 if (entry->flag & REF_DIR) {
564 struct ref_dir *subdir = get_ref_dir(entry);
565 sort_ref_dir(subdir);
566 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
567 } else {
568 retval = fn(entry, cb_data);
569 }
570 if (retval)
571 return retval;
572 }
573 return 0;
574}
575
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576/*
577 * Load all of the refs from the dir into our in-memory cache. The hard work
578 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
579 * through all of the sub-directories. We do not even need to care about
580 * sorting, as traversal order does not matter to us.
581 */
582static void prime_ref_dir(struct ref_dir *dir)
583{
584 int i;
585 for (i = 0; i < dir->nr; i++) {
586 struct ref_entry *entry = dir->entries[i];
587 if (entry->flag & REF_DIR)
588 prime_ref_dir(get_ref_dir(entry));
589 }
590}
591
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592/*
593 * A level in the reference hierarchy that is currently being iterated
594 * through.
595 */
596struct cache_ref_iterator_level {
597 /*
598 * The ref_dir being iterated over at this level. The ref_dir
599 * is sorted before being stored here.
600 */
601 struct ref_dir *dir;
602
603 /*
604 * The index of the current entry within dir (which might
605 * itself be a directory). If index == -1, then the iteration
606 * hasn't yet begun. If index == dir->nr, then the iteration
607 * through this level is over.
608 */
609 int index;
610};
611
612/*
613 * Represent an iteration through a ref_dir in the memory cache. The
614 * iteration recurses through subdirectories.
615 */
616struct cache_ref_iterator {
617 struct ref_iterator base;
618
619 /*
620 * The number of levels currently on the stack. This is always
621 * at least 1, because when it becomes zero the iteration is
622 * ended and this struct is freed.
623 */
624 size_t levels_nr;
625
626 /* The number of levels that have been allocated on the stack */
627 size_t levels_alloc;
628
629 /*
630 * A stack of levels. levels[0] is the uppermost level that is
631 * being iterated over in this iteration. (This is not
632 * necessary the top level in the references hierarchy. If we
633 * are iterating through a subtree, then levels[0] will hold
634 * the ref_dir for that subtree, and subsequent levels will go
635 * on from there.)
636 */
637 struct cache_ref_iterator_level *levels;
638};
639
640static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
641{
642 struct cache_ref_iterator *iter =
643 (struct cache_ref_iterator *)ref_iterator;
644
645 while (1) {
646 struct cache_ref_iterator_level *level =
647 &iter->levels[iter->levels_nr - 1];
648 struct ref_dir *dir = level->dir;
649 struct ref_entry *entry;
650
651 if (level->index == -1)
652 sort_ref_dir(dir);
653
654 if (++level->index == level->dir->nr) {
655 /* This level is exhausted; pop up a level */
656 if (--iter->levels_nr == 0)
657 return ref_iterator_abort(ref_iterator);
658
659 continue;
660 }
661
662 entry = dir->entries[level->index];
663
664 if (entry->flag & REF_DIR) {
665 /* push down a level */
666 ALLOC_GROW(iter->levels, iter->levels_nr + 1,
667 iter->levels_alloc);
668
669 level = &iter->levels[iter->levels_nr++];
670 level->dir = get_ref_dir(entry);
671 level->index = -1;
672 } else {
673 iter->base.refname = entry->name;
674 iter->base.oid = &entry->u.value.oid;
675 iter->base.flags = entry->flag;
676 return ITER_OK;
677 }
678 }
679}
680
681static enum peel_status peel_entry(struct ref_entry *entry, int repeel);
682
683static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
684 struct object_id *peeled)
685{
686 struct cache_ref_iterator *iter =
687 (struct cache_ref_iterator *)ref_iterator;
688 struct cache_ref_iterator_level *level;
689 struct ref_entry *entry;
690
691 level = &iter->levels[iter->levels_nr - 1];
692
693 if (level->index == -1)
694 die("BUG: peel called before advance for cache iterator");
695
696 entry = level->dir->entries[level->index];
697
698 if (peel_entry(entry, 0))
699 return -1;
700 hashcpy(peeled->hash, entry->u.value.peeled.hash);
701 return 0;
702}
703
704static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator)
705{
706 struct cache_ref_iterator *iter =
707 (struct cache_ref_iterator *)ref_iterator;
708
709 free(iter->levels);
710 base_ref_iterator_free(ref_iterator);
711 return ITER_DONE;
712}
713
714static struct ref_iterator_vtable cache_ref_iterator_vtable = {
715 cache_ref_iterator_advance,
716 cache_ref_iterator_peel,
717 cache_ref_iterator_abort
718};
719
720static struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir)
721{
722 struct cache_ref_iterator *iter;
723 struct ref_iterator *ref_iterator;
724 struct cache_ref_iterator_level *level;
725
726 iter = xcalloc(1, sizeof(*iter));
727 ref_iterator = &iter->base;
728 base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable);
729 ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
730
731 iter->levels_nr = 1;
732 level = &iter->levels[0];
733 level->index = -1;
734 level->dir = dir;
735
736 return ref_iterator;
737}
738
7bd9bcf3
MH
739struct nonmatching_ref_data {
740 const struct string_list *skip;
741 const char *conflicting_refname;
742};
743
744static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
745{
746 struct nonmatching_ref_data *data = vdata;
747
748 if (data->skip && string_list_has_string(data->skip, entry->name))
749 return 0;
750
751 data->conflicting_refname = entry->name;
752 return 1;
753}
754
755/*
756 * Return 0 if a reference named refname could be created without
757 * conflicting with the name of an existing reference in dir.
758 * See verify_refname_available for more information.
759 */
760static int verify_refname_available_dir(const char *refname,
761 const struct string_list *extras,
762 const struct string_list *skip,
763 struct ref_dir *dir,
764 struct strbuf *err)
765{
766 const char *slash;
0845122c 767 const char *extra_refname;
7bd9bcf3
MH
768 int pos;
769 struct strbuf dirname = STRBUF_INIT;
770 int ret = -1;
771
772 /*
773 * For the sake of comments in this function, suppose that
774 * refname is "refs/foo/bar".
775 */
776
777 assert(err);
778
779 strbuf_grow(&dirname, strlen(refname) + 1);
780 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
781 /* Expand dirname to the new prefix, not including the trailing slash: */
782 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
783
784 /*
785 * We are still at a leading dir of the refname (e.g.,
786 * "refs/foo"; if there is a reference with that name,
787 * it is a conflict, *unless* it is in skip.
788 */
789 if (dir) {
790 pos = search_ref_dir(dir, dirname.buf, dirname.len);
791 if (pos >= 0 &&
792 (!skip || !string_list_has_string(skip, dirname.buf))) {
793 /*
794 * We found a reference whose name is
795 * a proper prefix of refname; e.g.,
796 * "refs/foo", and is not in skip.
797 */
798 strbuf_addf(err, "'%s' exists; cannot create '%s'",
799 dirname.buf, refname);
800 goto cleanup;
801 }
802 }
803
804 if (extras && string_list_has_string(extras, dirname.buf) &&
805 (!skip || !string_list_has_string(skip, dirname.buf))) {
806 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
807 refname, dirname.buf);
808 goto cleanup;
809 }
810
811 /*
812 * Otherwise, we can try to continue our search with
813 * the next component. So try to look up the
814 * directory, e.g., "refs/foo/". If we come up empty,
815 * we know there is nothing under this whole prefix,
816 * but even in that case we still have to continue the
817 * search for conflicts with extras.
818 */
819 strbuf_addch(&dirname, '/');
820 if (dir) {
821 pos = search_ref_dir(dir, dirname.buf, dirname.len);
822 if (pos < 0) {
823 /*
824 * There was no directory "refs/foo/",
825 * so there is nothing under this
826 * whole prefix. So there is no need
827 * to continue looking for conflicting
828 * references. But we need to continue
829 * looking for conflicting extras.
830 */
831 dir = NULL;
832 } else {
833 dir = get_ref_dir(dir->entries[pos]);
834 }
835 }
836 }
837
838 /*
839 * We are at the leaf of our refname (e.g., "refs/foo/bar").
840 * There is no point in searching for a reference with that
841 * name, because a refname isn't considered to conflict with
842 * itself. But we still need to check for references whose
843 * names are in the "refs/foo/bar/" namespace, because they
844 * *do* conflict.
845 */
846 strbuf_addstr(&dirname, refname + dirname.len);
847 strbuf_addch(&dirname, '/');
848
849 if (dir) {
850 pos = search_ref_dir(dir, dirname.buf, dirname.len);
851
852 if (pos >= 0) {
853 /*
854 * We found a directory named "$refname/"
855 * (e.g., "refs/foo/bar/"). It is a problem
856 * iff it contains any ref that is not in
857 * "skip".
858 */
859 struct nonmatching_ref_data data;
860
861 data.skip = skip;
862 data.conflicting_refname = NULL;
863 dir = get_ref_dir(dir->entries[pos]);
864 sort_ref_dir(dir);
865 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
866 strbuf_addf(err, "'%s' exists; cannot create '%s'",
867 data.conflicting_refname, refname);
868 goto cleanup;
869 }
870 }
871 }
872
0845122c
DT
873 extra_refname = find_descendant_ref(dirname.buf, extras, skip);
874 if (extra_refname)
875 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
876 refname, extra_refname);
877 else
878 ret = 0;
7bd9bcf3
MH
879
880cleanup:
881 strbuf_release(&dirname);
882 return ret;
883}
884
885struct packed_ref_cache {
886 struct ref_entry *root;
887
888 /*
889 * Count of references to the data structure in this instance,
65a0a8e5
MH
890 * including the pointer from files_ref_store::packed if any.
891 * The data will not be freed as long as the reference count
892 * is nonzero.
7bd9bcf3
MH
893 */
894 unsigned int referrers;
895
896 /*
897 * Iff the packed-refs file associated with this instance is
898 * currently locked for writing, this points at the associated
899 * lock (which is owned by somebody else). The referrer count
900 * is also incremented when the file is locked and decremented
901 * when it is unlocked.
902 */
903 struct lock_file *lock;
904
905 /* The metadata from when this packed-refs cache was read */
906 struct stat_validity validity;
907};
908
909/*
910 * Future: need to be in "struct repository"
911 * when doing a full libification.
912 */
00eebe35
MH
913struct files_ref_store {
914 struct ref_store base;
7bd9bcf3
MH
915 struct ref_entry *loose;
916 struct packed_ref_cache *packed;
00eebe35 917};
7bd9bcf3
MH
918
919/* Lock used for the main packed-refs file: */
920static struct lock_file packlock;
921
922/*
923 * Increment the reference count of *packed_refs.
924 */
925static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
926{
927 packed_refs->referrers++;
928}
929
930/*
931 * Decrease the reference count of *packed_refs. If it goes to zero,
932 * free *packed_refs and return true; otherwise return false.
933 */
934static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
935{
936 if (!--packed_refs->referrers) {
937 free_ref_entry(packed_refs->root);
938 stat_validity_clear(&packed_refs->validity);
939 free(packed_refs);
940 return 1;
941 } else {
942 return 0;
943 }
944}
945
65a0a8e5 946static void clear_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
947{
948 if (refs->packed) {
949 struct packed_ref_cache *packed_refs = refs->packed;
950
951 if (packed_refs->lock)
952 die("internal error: packed-ref cache cleared while locked");
953 refs->packed = NULL;
954 release_packed_ref_cache(packed_refs);
955 }
956}
957
65a0a8e5 958static void clear_loose_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
959{
960 if (refs->loose) {
961 free_ref_entry(refs->loose);
962 refs->loose = NULL;
963 }
964}
965
a2d5156c
JK
966/*
967 * Create a new submodule ref cache and add it to the internal
968 * set of caches.
969 */
00eebe35 970static struct ref_store *files_ref_store_create(const char *submodule)
7bd9bcf3 971{
00eebe35
MH
972 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
973 struct ref_store *ref_store = (struct ref_store *)refs;
974
975 base_ref_store_init(ref_store, &refs_be_files, submodule);
976
977 return ref_store;
7bd9bcf3
MH
978}
979
00eebe35
MH
980/*
981 * Downcast ref_store to files_ref_store. Die if ref_store is not a
982 * files_ref_store. If submodule_allowed is not true, then also die if
983 * files_ref_store is for a submodule (i.e., not for the main
984 * repository). caller is used in any necessary error messages.
985 */
986static struct files_ref_store *files_downcast(
987 struct ref_store *ref_store, int submodule_allowed,
988 const char *caller)
7bd9bcf3 989{
00eebe35
MH
990 if (ref_store->be != &refs_be_files)
991 die("BUG: ref_store is type \"%s\" not \"files\" in %s",
992 ref_store->be->name, caller);
7bd9bcf3 993
00eebe35
MH
994 if (!submodule_allowed)
995 assert_main_repository(ref_store, caller);
7bd9bcf3 996
00eebe35 997 return (struct files_ref_store *)ref_store;
a2d5156c 998}
7bd9bcf3 999
7bd9bcf3
MH
1000/* The length of a peeled reference line in packed-refs, including EOL: */
1001#define PEELED_LINE_LENGTH 42
1002
1003/*
1004 * The packed-refs header line that we write out. Perhaps other
1005 * traits will be added later. The trailing space is required.
1006 */
1007static const char PACKED_REFS_HEADER[] =
1008 "# pack-refs with: peeled fully-peeled \n";
1009
1010/*
1011 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1012 * Return a pointer to the refname within the line (null-terminated),
1013 * or NULL if there was a problem.
1014 */
1015static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1016{
1017 const char *ref;
1018
1019 /*
1020 * 42: the answer to everything.
1021 *
1022 * In this case, it happens to be the answer to
1023 * 40 (length of sha1 hex representation)
1024 * +1 (space in between hex and name)
1025 * +1 (newline at the end of the line)
1026 */
1027 if (line->len <= 42)
1028 return NULL;
1029
1030 if (get_sha1_hex(line->buf, sha1) < 0)
1031 return NULL;
1032 if (!isspace(line->buf[40]))
1033 return NULL;
1034
1035 ref = line->buf + 41;
1036 if (isspace(*ref))
1037 return NULL;
1038
1039 if (line->buf[line->len - 1] != '\n')
1040 return NULL;
1041 line->buf[--line->len] = 0;
1042
1043 return ref;
1044}
1045
1046/*
1047 * Read f, which is a packed-refs file, into dir.
1048 *
1049 * A comment line of the form "# pack-refs with: " may contain zero or
1050 * more traits. We interpret the traits as follows:
1051 *
1052 * No traits:
1053 *
1054 * Probably no references are peeled. But if the file contains a
1055 * peeled value for a reference, we will use it.
1056 *
1057 * peeled:
1058 *
1059 * References under "refs/tags/", if they *can* be peeled, *are*
1060 * peeled in this file. References outside of "refs/tags/" are
1061 * probably not peeled even if they could have been, but if we find
1062 * a peeled value for such a reference we will use it.
1063 *
1064 * fully-peeled:
1065 *
1066 * All references in the file that can be peeled are peeled.
1067 * Inversely (and this is more important), any references in the
1068 * file for which no peeled value is recorded is not peelable. This
1069 * trait should typically be written alongside "peeled" for
1070 * compatibility with older clients, but we do not require it
1071 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1072 */
1073static void read_packed_refs(FILE *f, struct ref_dir *dir)
1074{
1075 struct ref_entry *last = NULL;
1076 struct strbuf line = STRBUF_INIT;
1077 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1078
1079 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1080 unsigned char sha1[20];
1081 const char *refname;
1082 const char *traits;
1083
1084 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1085 if (strstr(traits, " fully-peeled "))
1086 peeled = PEELED_FULLY;
1087 else if (strstr(traits, " peeled "))
1088 peeled = PEELED_TAGS;
1089 /* perhaps other traits later as well */
1090 continue;
1091 }
1092
1093 refname = parse_ref_line(&line, sha1);
1094 if (refname) {
1095 int flag = REF_ISPACKED;
1096
1097 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1098 if (!refname_is_safe(refname))
1099 die("packed refname is dangerous: %s", refname);
1100 hashclr(sha1);
1101 flag |= REF_BAD_NAME | REF_ISBROKEN;
1102 }
1103 last = create_ref_entry(refname, sha1, flag, 0);
1104 if (peeled == PEELED_FULLY ||
1105 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1106 last->flag |= REF_KNOWS_PEELED;
1107 add_ref(dir, last);
1108 continue;
1109 }
1110 if (last &&
1111 line.buf[0] == '^' &&
1112 line.len == PEELED_LINE_LENGTH &&
1113 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1114 !get_sha1_hex(line.buf + 1, sha1)) {
1115 hashcpy(last->u.value.peeled.hash, sha1);
1116 /*
1117 * Regardless of what the file header said,
1118 * we definitely know the value of *this*
1119 * reference:
1120 */
1121 last->flag |= REF_KNOWS_PEELED;
1122 }
1123 }
1124
1125 strbuf_release(&line);
1126}
1127
1128/*
65a0a8e5
MH
1129 * Get the packed_ref_cache for the specified files_ref_store,
1130 * creating it if necessary.
7bd9bcf3 1131 */
65a0a8e5 1132static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
1133{
1134 char *packed_refs_file;
1135
00eebe35
MH
1136 if (*refs->base.submodule)
1137 packed_refs_file = git_pathdup_submodule(refs->base.submodule,
1138 "packed-refs");
7bd9bcf3
MH
1139 else
1140 packed_refs_file = git_pathdup("packed-refs");
1141
1142 if (refs->packed &&
1143 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1144 clear_packed_ref_cache(refs);
1145
1146 if (!refs->packed) {
1147 FILE *f;
1148
1149 refs->packed = xcalloc(1, sizeof(*refs->packed));
1150 acquire_packed_ref_cache(refs->packed);
1151 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1152 f = fopen(packed_refs_file, "r");
1153 if (f) {
1154 stat_validity_update(&refs->packed->validity, fileno(f));
1155 read_packed_refs(f, get_ref_dir(refs->packed->root));
1156 fclose(f);
1157 }
1158 }
1159 free(packed_refs_file);
1160 return refs->packed;
1161}
1162
1163static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1164{
1165 return get_ref_dir(packed_ref_cache->root);
1166}
1167
65a0a8e5 1168static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1169{
1170 return get_packed_ref_dir(get_packed_ref_cache(refs));
1171}
1172
1173/*
1174 * Add a reference to the in-memory packed reference cache. This may
1175 * only be called while the packed-refs file is locked (see
1176 * lock_packed_refs()). To actually write the packed-refs file, call
1177 * commit_packed_refs().
1178 */
d99825ab
MH
1179static void add_packed_ref(struct files_ref_store *refs,
1180 const char *refname, const unsigned char *sha1)
7bd9bcf3 1181{
00eebe35 1182 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
1183
1184 if (!packed_ref_cache->lock)
1185 die("internal error: packed refs not locked");
1186 add_ref(get_packed_ref_dir(packed_ref_cache),
1187 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1188}
1189
1190/*
1191 * Read the loose references from the namespace dirname into dir
1192 * (without recursing). dirname must end with '/'. dir must be the
1193 * directory entry corresponding to dirname.
1194 */
1195static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1196{
65a0a8e5 1197 struct files_ref_store *refs = dir->ref_store;
7bd9bcf3
MH
1198 DIR *d;
1199 struct dirent *de;
1200 int dirnamelen = strlen(dirname);
1201 struct strbuf refname;
1202 struct strbuf path = STRBUF_INIT;
1203 size_t path_baselen;
1204
00eebe35
MH
1205 if (*refs->base.submodule)
1206 strbuf_git_path_submodule(&path, refs->base.submodule, "%s", dirname);
7bd9bcf3
MH
1207 else
1208 strbuf_git_path(&path, "%s", dirname);
1209 path_baselen = path.len;
1210
1211 d = opendir(path.buf);
1212 if (!d) {
1213 strbuf_release(&path);
1214 return;
1215 }
1216
1217 strbuf_init(&refname, dirnamelen + 257);
1218 strbuf_add(&refname, dirname, dirnamelen);
1219
1220 while ((de = readdir(d)) != NULL) {
1221 unsigned char sha1[20];
1222 struct stat st;
1223 int flag;
1224
1225 if (de->d_name[0] == '.')
1226 continue;
1227 if (ends_with(de->d_name, ".lock"))
1228 continue;
1229 strbuf_addstr(&refname, de->d_name);
1230 strbuf_addstr(&path, de->d_name);
1231 if (stat(path.buf, &st) < 0) {
1232 ; /* silently ignore */
1233 } else if (S_ISDIR(st.st_mode)) {
1234 strbuf_addch(&refname, '/');
1235 add_entry_to_dir(dir,
1236 create_dir_entry(refs, refname.buf,
1237 refname.len, 1));
1238 } else {
1239 int read_ok;
1240
00eebe35 1241 if (*refs->base.submodule) {
7bd9bcf3
MH
1242 hashclr(sha1);
1243 flag = 0;
00eebe35 1244 read_ok = !resolve_gitlink_ref(refs->base.submodule,
7bd9bcf3
MH
1245 refname.buf, sha1);
1246 } else {
1247 read_ok = !read_ref_full(refname.buf,
1248 RESOLVE_REF_READING,
1249 sha1, &flag);
1250 }
1251
1252 if (!read_ok) {
1253 hashclr(sha1);
1254 flag |= REF_ISBROKEN;
1255 } else if (is_null_sha1(sha1)) {
1256 /*
1257 * It is so astronomically unlikely
1258 * that NULL_SHA1 is the SHA-1 of an
1259 * actual object that we consider its
1260 * appearance in a loose reference
1261 * file to be repo corruption
1262 * (probably due to a software bug).
1263 */
1264 flag |= REF_ISBROKEN;
1265 }
1266
1267 if (check_refname_format(refname.buf,
1268 REFNAME_ALLOW_ONELEVEL)) {
1269 if (!refname_is_safe(refname.buf))
1270 die("loose refname is dangerous: %s", refname.buf);
1271 hashclr(sha1);
1272 flag |= REF_BAD_NAME | REF_ISBROKEN;
1273 }
1274 add_entry_to_dir(dir,
1275 create_ref_entry(refname.buf, sha1, flag, 0));
1276 }
1277 strbuf_setlen(&refname, dirnamelen);
1278 strbuf_setlen(&path, path_baselen);
1279 }
1280 strbuf_release(&refname);
1281 strbuf_release(&path);
1282 closedir(d);
1283}
1284
65a0a8e5 1285static struct ref_dir *get_loose_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1286{
1287 if (!refs->loose) {
1288 /*
1289 * Mark the top-level directory complete because we
1290 * are about to read the only subdirectory that can
1291 * hold references:
1292 */
1293 refs->loose = create_dir_entry(refs, "", 0, 0);
1294 /*
1295 * Create an incomplete entry for "refs/":
1296 */
1297 add_entry_to_dir(get_ref_dir(refs->loose),
1298 create_dir_entry(refs, "refs/", 5, 1));
1299 }
1300 return get_ref_dir(refs->loose);
1301}
1302
7bd9bcf3
MH
1303/*
1304 * Return the ref_entry for the given refname from the packed
1305 * references. If it does not exist, return NULL.
1306 */
f0d21efc
MH
1307static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
1308 const char *refname)
7bd9bcf3 1309{
00eebe35 1310 return find_ref(get_packed_refs(refs), refname);
7bd9bcf3
MH
1311}
1312
1313/*
419c6f4c 1314 * A loose ref file doesn't exist; check for a packed ref.
7bd9bcf3 1315 */
611118d0
MH
1316static int resolve_packed_ref(struct files_ref_store *refs,
1317 const char *refname,
1318 unsigned char *sha1, unsigned int *flags)
7bd9bcf3
MH
1319{
1320 struct ref_entry *entry;
1321
1322 /*
1323 * The loose reference file does not exist; check for a packed
1324 * reference.
1325 */
f0d21efc 1326 entry = get_packed_ref(refs, refname);
7bd9bcf3
MH
1327 if (entry) {
1328 hashcpy(sha1, entry->u.value.oid.hash);
a70a93b7 1329 *flags |= REF_ISPACKED;
7bd9bcf3
MH
1330 return 0;
1331 }
419c6f4c
MH
1332 /* refname is not a packed reference. */
1333 return -1;
7bd9bcf3
MH
1334}
1335
e1e33b72
MH
1336static int files_read_raw_ref(struct ref_store *ref_store,
1337 const char *refname, unsigned char *sha1,
1338 struct strbuf *referent, unsigned int *type)
7bd9bcf3 1339{
4308651c 1340 struct files_ref_store *refs =
34c7ad8f 1341 files_downcast(ref_store, 1, "read_raw_ref");
42a38cf7
MH
1342 struct strbuf sb_contents = STRBUF_INIT;
1343 struct strbuf sb_path = STRBUF_INIT;
7048653a
DT
1344 const char *path;
1345 const char *buf;
1346 struct stat st;
1347 int fd;
42a38cf7
MH
1348 int ret = -1;
1349 int save_errno;
7bd9bcf3 1350
fa96ea1b 1351 *type = 0;
42a38cf7 1352 strbuf_reset(&sb_path);
34c7ad8f
MH
1353
1354 if (*refs->base.submodule)
1355 strbuf_git_path_submodule(&sb_path, refs->base.submodule, "%s", refname);
1356 else
1357 strbuf_git_path(&sb_path, "%s", refname);
1358
42a38cf7 1359 path = sb_path.buf;
7bd9bcf3 1360
7048653a
DT
1361stat_ref:
1362 /*
1363 * We might have to loop back here to avoid a race
1364 * condition: first we lstat() the file, then we try
1365 * to read it as a link or as a file. But if somebody
1366 * changes the type of the file (file <-> directory
1367 * <-> symlink) between the lstat() and reading, then
1368 * we don't want to report that as an error but rather
1369 * try again starting with the lstat().
1370 */
7bd9bcf3 1371
7048653a
DT
1372 if (lstat(path, &st) < 0) {
1373 if (errno != ENOENT)
42a38cf7 1374 goto out;
611118d0 1375 if (resolve_packed_ref(refs, refname, sha1, type)) {
7048653a 1376 errno = ENOENT;
42a38cf7 1377 goto out;
7bd9bcf3 1378 }
42a38cf7
MH
1379 ret = 0;
1380 goto out;
7bd9bcf3 1381 }
7bd9bcf3 1382
7048653a
DT
1383 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1384 if (S_ISLNK(st.st_mode)) {
42a38cf7
MH
1385 strbuf_reset(&sb_contents);
1386 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
7048653a 1387 if (errno == ENOENT || errno == EINVAL)
7bd9bcf3
MH
1388 /* inconsistent with lstat; retry */
1389 goto stat_ref;
1390 else
42a38cf7 1391 goto out;
7bd9bcf3 1392 }
42a38cf7
MH
1393 if (starts_with(sb_contents.buf, "refs/") &&
1394 !check_refname_format(sb_contents.buf, 0)) {
92b38093 1395 strbuf_swap(&sb_contents, referent);
3a0b6b9a 1396 *type |= REF_ISSYMREF;
42a38cf7
MH
1397 ret = 0;
1398 goto out;
7bd9bcf3 1399 }
7048653a 1400 }
7bd9bcf3 1401
7048653a
DT
1402 /* Is it a directory? */
1403 if (S_ISDIR(st.st_mode)) {
e167a567
MH
1404 /*
1405 * Even though there is a directory where the loose
1406 * ref is supposed to be, there could still be a
1407 * packed ref:
1408 */
611118d0 1409 if (resolve_packed_ref(refs, refname, sha1, type)) {
e167a567
MH
1410 errno = EISDIR;
1411 goto out;
1412 }
1413 ret = 0;
42a38cf7 1414 goto out;
7048653a
DT
1415 }
1416
1417 /*
1418 * Anything else, just open it and try to use it as
1419 * a ref
1420 */
1421 fd = open(path, O_RDONLY);
1422 if (fd < 0) {
1423 if (errno == ENOENT)
1424 /* inconsistent with lstat; retry */
1425 goto stat_ref;
1426 else
42a38cf7 1427 goto out;
7048653a 1428 }
42a38cf7
MH
1429 strbuf_reset(&sb_contents);
1430 if (strbuf_read(&sb_contents, fd, 256) < 0) {
7048653a
DT
1431 int save_errno = errno;
1432 close(fd);
1433 errno = save_errno;
42a38cf7 1434 goto out;
7048653a
DT
1435 }
1436 close(fd);
42a38cf7
MH
1437 strbuf_rtrim(&sb_contents);
1438 buf = sb_contents.buf;
7048653a
DT
1439 if (starts_with(buf, "ref:")) {
1440 buf += 4;
7bd9bcf3
MH
1441 while (isspace(*buf))
1442 buf++;
7048653a 1443
92b38093
MH
1444 strbuf_reset(referent);
1445 strbuf_addstr(referent, buf);
3a0b6b9a 1446 *type |= REF_ISSYMREF;
42a38cf7
MH
1447 ret = 0;
1448 goto out;
7bd9bcf3 1449 }
7bd9bcf3 1450
7048653a
DT
1451 /*
1452 * Please note that FETCH_HEAD has additional
1453 * data after the sha.
1454 */
1455 if (get_sha1_hex(buf, sha1) ||
1456 (buf[40] != '\0' && !isspace(buf[40]))) {
3a0b6b9a 1457 *type |= REF_ISBROKEN;
7048653a 1458 errno = EINVAL;
42a38cf7 1459 goto out;
7048653a
DT
1460 }
1461
42a38cf7 1462 ret = 0;
7bd9bcf3 1463
42a38cf7
MH
1464out:
1465 save_errno = errno;
7bd9bcf3
MH
1466 strbuf_release(&sb_path);
1467 strbuf_release(&sb_contents);
42a38cf7 1468 errno = save_errno;
7bd9bcf3
MH
1469 return ret;
1470}
1471
8415d247
MH
1472static void unlock_ref(struct ref_lock *lock)
1473{
1474 /* Do not free lock->lk -- atexit() still looks at them */
1475 if (lock->lk)
1476 rollback_lock_file(lock->lk);
1477 free(lock->ref_name);
8415d247
MH
1478 free(lock);
1479}
1480
92b1551b
MH
1481/*
1482 * Lock refname, without following symrefs, and set *lock_p to point
1483 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
1484 * and type similarly to read_raw_ref().
1485 *
1486 * The caller must verify that refname is a "safe" reference name (in
1487 * the sense of refname_is_safe()) before calling this function.
1488 *
1489 * If the reference doesn't already exist, verify that refname doesn't
1490 * have a D/F conflict with any existing references. extras and skip
1491 * are passed to verify_refname_available_dir() for this check.
1492 *
1493 * If mustexist is not set and the reference is not found or is
1494 * broken, lock the reference anyway but clear sha1.
1495 *
1496 * Return 0 on success. On failure, write an error message to err and
1497 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
1498 *
1499 * Implementation note: This function is basically
1500 *
1501 * lock reference
1502 * read_raw_ref()
1503 *
1504 * but it includes a lot more code to
1505 * - Deal with possible races with other processes
1506 * - Avoid calling verify_refname_available_dir() when it can be
1507 * avoided, namely if we were successfully able to read the ref
1508 * - Generate informative error messages in the case of failure
1509 */
f7b0a987
MH
1510static int lock_raw_ref(struct files_ref_store *refs,
1511 const char *refname, int mustexist,
92b1551b
MH
1512 const struct string_list *extras,
1513 const struct string_list *skip,
1514 struct ref_lock **lock_p,
1515 struct strbuf *referent,
1516 unsigned int *type,
1517 struct strbuf *err)
1518{
1519 struct ref_lock *lock;
1520 struct strbuf ref_file = STRBUF_INIT;
1521 int attempts_remaining = 3;
1522 int ret = TRANSACTION_GENERIC_ERROR;
1523
1524 assert(err);
f7b0a987
MH
1525 assert_main_repository(&refs->base, "lock_raw_ref");
1526
92b1551b
MH
1527 *type = 0;
1528
1529 /* First lock the file so it can't change out from under us. */
1530
1531 *lock_p = lock = xcalloc(1, sizeof(*lock));
1532
1533 lock->ref_name = xstrdup(refname);
92b1551b
MH
1534 strbuf_git_path(&ref_file, "%s", refname);
1535
1536retry:
1537 switch (safe_create_leading_directories(ref_file.buf)) {
1538 case SCLD_OK:
1539 break; /* success */
1540 case SCLD_EXISTS:
1541 /*
1542 * Suppose refname is "refs/foo/bar". We just failed
1543 * to create the containing directory, "refs/foo",
1544 * because there was a non-directory in the way. This
1545 * indicates a D/F conflict, probably because of
1546 * another reference such as "refs/foo". There is no
1547 * reason to expect this error to be transitory.
1548 */
1549 if (verify_refname_available(refname, extras, skip, err)) {
1550 if (mustexist) {
1551 /*
1552 * To the user the relevant error is
1553 * that the "mustexist" reference is
1554 * missing:
1555 */
1556 strbuf_reset(err);
1557 strbuf_addf(err, "unable to resolve reference '%s'",
1558 refname);
1559 } else {
1560 /*
1561 * The error message set by
1562 * verify_refname_available_dir() is OK.
1563 */
1564 ret = TRANSACTION_NAME_CONFLICT;
1565 }
1566 } else {
1567 /*
1568 * The file that is in the way isn't a loose
1569 * reference. Report it as a low-level
1570 * failure.
1571 */
1572 strbuf_addf(err, "unable to create lock file %s.lock; "
1573 "non-directory in the way",
1574 ref_file.buf);
1575 }
1576 goto error_return;
1577 case SCLD_VANISHED:
1578 /* Maybe another process was tidying up. Try again. */
1579 if (--attempts_remaining > 0)
1580 goto retry;
1581 /* fall through */
1582 default:
1583 strbuf_addf(err, "unable to create directory for %s",
1584 ref_file.buf);
1585 goto error_return;
1586 }
1587
1588 if (!lock->lk)
1589 lock->lk = xcalloc(1, sizeof(struct lock_file));
1590
1591 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
1592 if (errno == ENOENT && --attempts_remaining > 0) {
1593 /*
1594 * Maybe somebody just deleted one of the
1595 * directories leading to ref_file. Try
1596 * again:
1597 */
1598 goto retry;
1599 } else {
1600 unable_to_lock_message(ref_file.buf, errno, err);
1601 goto error_return;
1602 }
1603 }
1604
1605 /*
1606 * Now we hold the lock and can read the reference without
1607 * fear that its value will change.
1608 */
1609
f7b0a987 1610 if (files_read_raw_ref(&refs->base, refname,
e1e33b72 1611 lock->old_oid.hash, referent, type)) {
92b1551b
MH
1612 if (errno == ENOENT) {
1613 if (mustexist) {
1614 /* Garden variety missing reference. */
1615 strbuf_addf(err, "unable to resolve reference '%s'",
1616 refname);
1617 goto error_return;
1618 } else {
1619 /*
1620 * Reference is missing, but that's OK. We
1621 * know that there is not a conflict with
1622 * another loose reference because
1623 * (supposing that we are trying to lock
1624 * reference "refs/foo/bar"):
1625 *
1626 * - We were successfully able to create
1627 * the lockfile refs/foo/bar.lock, so we
1628 * know there cannot be a loose reference
1629 * named "refs/foo".
1630 *
1631 * - We got ENOENT and not EISDIR, so we
1632 * know that there cannot be a loose
1633 * reference named "refs/foo/bar/baz".
1634 */
1635 }
1636 } else if (errno == EISDIR) {
1637 /*
1638 * There is a directory in the way. It might have
1639 * contained references that have been deleted. If
1640 * we don't require that the reference already
1641 * exists, try to remove the directory so that it
1642 * doesn't cause trouble when we want to rename the
1643 * lockfile into place later.
1644 */
1645 if (mustexist) {
1646 /* Garden variety missing reference. */
1647 strbuf_addf(err, "unable to resolve reference '%s'",
1648 refname);
1649 goto error_return;
1650 } else if (remove_dir_recursively(&ref_file,
1651 REMOVE_DIR_EMPTY_ONLY)) {
1652 if (verify_refname_available_dir(
1653 refname, extras, skip,
00eebe35 1654 get_loose_refs(refs),
92b1551b
MH
1655 err)) {
1656 /*
1657 * The error message set by
1658 * verify_refname_available() is OK.
1659 */
1660 ret = TRANSACTION_NAME_CONFLICT;
1661 goto error_return;
1662 } else {
1663 /*
1664 * We can't delete the directory,
1665 * but we also don't know of any
1666 * references that it should
1667 * contain.
1668 */
1669 strbuf_addf(err, "there is a non-empty directory '%s' "
1670 "blocking reference '%s'",
1671 ref_file.buf, refname);
1672 goto error_return;
1673 }
1674 }
1675 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
1676 strbuf_addf(err, "unable to resolve reference '%s': "
1677 "reference broken", refname);
1678 goto error_return;
1679 } else {
1680 strbuf_addf(err, "unable to resolve reference '%s': %s",
1681 refname, strerror(errno));
1682 goto error_return;
1683 }
1684
1685 /*
1686 * If the ref did not exist and we are creating it,
1687 * make sure there is no existing packed ref whose
1688 * name begins with our refname, nor a packed ref
1689 * whose name is a proper prefix of our refname.
1690 */
1691 if (verify_refname_available_dir(
1692 refname, extras, skip,
00eebe35 1693 get_packed_refs(refs),
92b1551b
MH
1694 err)) {
1695 goto error_return;
1696 }
1697 }
1698
1699 ret = 0;
1700 goto out;
1701
1702error_return:
1703 unlock_ref(lock);
1704 *lock_p = NULL;
1705
1706out:
1707 strbuf_release(&ref_file);
1708 return ret;
1709}
1710
7bd9bcf3
MH
1711/*
1712 * Peel the entry (if possible) and return its new peel_status. If
1713 * repeel is true, re-peel the entry even if there is an old peeled
1714 * value that is already stored in it.
1715 *
1716 * It is OK to call this function with a packed reference entry that
1717 * might be stale and might even refer to an object that has since
1718 * been garbage-collected. In such a case, if the entry has
1719 * REF_KNOWS_PEELED then leave the status unchanged and return
1720 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1721 */
1722static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1723{
1724 enum peel_status status;
1725
1726 if (entry->flag & REF_KNOWS_PEELED) {
1727 if (repeel) {
1728 entry->flag &= ~REF_KNOWS_PEELED;
1729 oidclr(&entry->u.value.peeled);
1730 } else {
1731 return is_null_oid(&entry->u.value.peeled) ?
1732 PEEL_NON_TAG : PEEL_PEELED;
1733 }
1734 }
1735 if (entry->flag & REF_ISBROKEN)
1736 return PEEL_BROKEN;
1737 if (entry->flag & REF_ISSYMREF)
1738 return PEEL_IS_SYMREF;
1739
1740 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1741 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1742 entry->flag |= REF_KNOWS_PEELED;
1743 return status;
1744}
1745
bd427cf2
MH
1746static int files_peel_ref(struct ref_store *ref_store,
1747 const char *refname, unsigned char *sha1)
7bd9bcf3 1748{
bd427cf2 1749 struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
7bd9bcf3
MH
1750 int flag;
1751 unsigned char base[20];
1752
4c4de895
MH
1753 if (current_ref_iter && current_ref_iter->refname == refname) {
1754 struct object_id peeled;
1755
1756 if (ref_iterator_peel(current_ref_iter, &peeled))
7bd9bcf3 1757 return -1;
4c4de895 1758 hashcpy(sha1, peeled.hash);
7bd9bcf3
MH
1759 return 0;
1760 }
1761
1762 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1763 return -1;
1764
1765 /*
1766 * If the reference is packed, read its ref_entry from the
1767 * cache in the hope that we already know its peeled value.
1768 * We only try this optimization on packed references because
1769 * (a) forcing the filling of the loose reference cache could
1770 * be expensive and (b) loose references anyway usually do not
1771 * have REF_KNOWS_PEELED.
1772 */
1773 if (flag & REF_ISPACKED) {
f0d21efc 1774 struct ref_entry *r = get_packed_ref(refs, refname);
7bd9bcf3
MH
1775 if (r) {
1776 if (peel_entry(r, 0))
1777 return -1;
1778 hashcpy(sha1, r->u.value.peeled.hash);
1779 return 0;
1780 }
1781 }
1782
1783 return peel_object(base, sha1);
1784}
1785
3bc581b9
MH
1786struct files_ref_iterator {
1787 struct ref_iterator base;
1788
1789 struct packed_ref_cache *packed_ref_cache;
1790 struct ref_iterator *iter0;
1791 unsigned int flags;
1792};
1793
1794static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
1795{
1796 struct files_ref_iterator *iter =
1797 (struct files_ref_iterator *)ref_iterator;
1798 int ok;
1799
1800 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
1801 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
1802 !ref_resolves_to_object(iter->iter0->refname,
1803 iter->iter0->oid,
1804 iter->iter0->flags))
1805 continue;
1806
1807 iter->base.refname = iter->iter0->refname;
1808 iter->base.oid = iter->iter0->oid;
1809 iter->base.flags = iter->iter0->flags;
1810 return ITER_OK;
1811 }
1812
1813 iter->iter0 = NULL;
1814 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
1815 ok = ITER_ERROR;
1816
1817 return ok;
1818}
1819
1820static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
1821 struct object_id *peeled)
1822{
1823 struct files_ref_iterator *iter =
1824 (struct files_ref_iterator *)ref_iterator;
1825
1826 return ref_iterator_peel(iter->iter0, peeled);
1827}
1828
1829static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
1830{
1831 struct files_ref_iterator *iter =
1832 (struct files_ref_iterator *)ref_iterator;
1833 int ok = ITER_DONE;
1834
1835 if (iter->iter0)
1836 ok = ref_iterator_abort(iter->iter0);
1837
1838 release_packed_ref_cache(iter->packed_ref_cache);
1839 base_ref_iterator_free(ref_iterator);
1840 return ok;
1841}
1842
1843static struct ref_iterator_vtable files_ref_iterator_vtable = {
1844 files_ref_iterator_advance,
1845 files_ref_iterator_peel,
1846 files_ref_iterator_abort
1847};
1848
1a769003 1849static struct ref_iterator *files_ref_iterator_begin(
37b6f6d5 1850 struct ref_store *ref_store,
3bc581b9
MH
1851 const char *prefix, unsigned int flags)
1852{
00eebe35 1853 struct files_ref_store *refs =
37b6f6d5 1854 files_downcast(ref_store, 1, "ref_iterator_begin");
3bc581b9
MH
1855 struct ref_dir *loose_dir, *packed_dir;
1856 struct ref_iterator *loose_iter, *packed_iter;
1857 struct files_ref_iterator *iter;
1858 struct ref_iterator *ref_iterator;
1859
1860 if (!refs)
1861 return empty_ref_iterator_begin();
1862
1863 if (ref_paranoia < 0)
1864 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1865 if (ref_paranoia)
1866 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1867
1868 iter = xcalloc(1, sizeof(*iter));
1869 ref_iterator = &iter->base;
1870 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
1871
1872 /*
1873 * We must make sure that all loose refs are read before
1874 * accessing the packed-refs file; this avoids a race
1875 * condition if loose refs are migrated to the packed-refs
1876 * file by a simultaneous process, but our in-memory view is
1877 * from before the migration. We ensure this as follows:
1878 * First, we call prime_ref_dir(), which pre-reads the loose
1879 * references for the subtree into the cache. (If they've
1880 * already been read, that's OK; we only need to guarantee
1881 * that they're read before the packed refs, not *how much*
1882 * before.) After that, we call get_packed_ref_cache(), which
1883 * internally checks whether the packed-ref cache is up to
1884 * date with what is on disk, and re-reads it if not.
1885 */
1886
1887 loose_dir = get_loose_refs(refs);
1888
1889 if (prefix && *prefix)
1890 loose_dir = find_containing_dir(loose_dir, prefix, 0);
1891
1892 if (loose_dir) {
1893 prime_ref_dir(loose_dir);
1894 loose_iter = cache_ref_iterator_begin(loose_dir);
1895 } else {
1896 /* There's nothing to iterate over. */
1897 loose_iter = empty_ref_iterator_begin();
1898 }
1899
1900 iter->packed_ref_cache = get_packed_ref_cache(refs);
1901 acquire_packed_ref_cache(iter->packed_ref_cache);
1902 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);
1903
1904 if (prefix && *prefix)
1905 packed_dir = find_containing_dir(packed_dir, prefix, 0);
1906
1907 if (packed_dir) {
1908 packed_iter = cache_ref_iterator_begin(packed_dir);
1909 } else {
1910 /* There's nothing to iterate over. */
1911 packed_iter = empty_ref_iterator_begin();
1912 }
1913
1914 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
1915 iter->flags = flags;
1916
1917 return ref_iterator;
1918}
1919
7bd9bcf3
MH
1920/*
1921 * Verify that the reference locked by lock has the value old_sha1.
1922 * Fail if the reference doesn't exist and mustexist is set. Return 0
1923 * on success. On error, write an error message to err, set errno, and
1924 * return a negative value.
1925 */
1926static int verify_lock(struct ref_lock *lock,
1927 const unsigned char *old_sha1, int mustexist,
1928 struct strbuf *err)
1929{
1930 assert(err);
1931
1932 if (read_ref_full(lock->ref_name,
1933 mustexist ? RESOLVE_REF_READING : 0,
1934 lock->old_oid.hash, NULL)) {
6294dcb4
JK
1935 if (old_sha1) {
1936 int save_errno = errno;
0568c8e9 1937 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
6294dcb4
JK
1938 errno = save_errno;
1939 return -1;
1940 } else {
1941 hashclr(lock->old_oid.hash);
1942 return 0;
1943 }
7bd9bcf3 1944 }
6294dcb4 1945 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
0568c8e9 1946 strbuf_addf(err, "ref '%s' is at %s but expected %s",
7bd9bcf3
MH
1947 lock->ref_name,
1948 sha1_to_hex(lock->old_oid.hash),
1949 sha1_to_hex(old_sha1));
1950 errno = EBUSY;
1951 return -1;
1952 }
1953 return 0;
1954}
1955
1956static int remove_empty_directories(struct strbuf *path)
1957{
1958 /*
1959 * we want to create a file but there is a directory there;
1960 * if that is an empty directory (or a directory that contains
1961 * only empty directories), remove them.
1962 */
1963 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
1964}
1965
1966/*
1967 * Locks a ref returning the lock on success and NULL on failure.
1968 * On failure errno is set to something meaningful.
1969 */
7eb27cdf
MH
1970static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
1971 const char *refname,
7bd9bcf3
MH
1972 const unsigned char *old_sha1,
1973 const struct string_list *extras,
1974 const struct string_list *skip,
bcb497d0 1975 unsigned int flags, int *type,
7bd9bcf3
MH
1976 struct strbuf *err)
1977{
1978 struct strbuf ref_file = STRBUF_INIT;
7bd9bcf3
MH
1979 struct ref_lock *lock;
1980 int last_errno = 0;
7a418f3a 1981 int lflags = LOCK_NO_DEREF;
7bd9bcf3 1982 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
7a418f3a 1983 int resolve_flags = RESOLVE_REF_NO_RECURSE;
7bd9bcf3 1984 int attempts_remaining = 3;
7a418f3a 1985 int resolved;
7bd9bcf3 1986
7eb27cdf 1987 assert_main_repository(&refs->base, "lock_ref_sha1_basic");
7bd9bcf3
MH
1988 assert(err);
1989
1990 lock = xcalloc(1, sizeof(struct ref_lock));
1991
1992 if (mustexist)
1993 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 1994 if (flags & REF_DELETING)
7bd9bcf3 1995 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
7bd9bcf3 1996
7a418f3a
MH
1997 strbuf_git_path(&ref_file, "%s", refname);
1998 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
1999 lock->old_oid.hash, type);
2000 if (!resolved && errno == EISDIR) {
7bd9bcf3
MH
2001 /*
2002 * we are trying to lock foo but we used to
2003 * have foo/bar which now does not exist;
2004 * it is normal for the empty directory 'foo'
2005 * to remain.
2006 */
7a418f3a 2007 if (remove_empty_directories(&ref_file)) {
7bd9bcf3 2008 last_errno = errno;
00eebe35
MH
2009 if (!verify_refname_available_dir(
2010 refname, extras, skip,
2011 get_loose_refs(refs), err))
7bd9bcf3 2012 strbuf_addf(err, "there are still refs under '%s'",
7a418f3a 2013 refname);
7bd9bcf3
MH
2014 goto error_return;
2015 }
7a418f3a
MH
2016 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2017 lock->old_oid.hash, type);
7bd9bcf3 2018 }
7a418f3a 2019 if (!resolved) {
7bd9bcf3
MH
2020 last_errno = errno;
2021 if (last_errno != ENOTDIR ||
00eebe35
MH
2022 !verify_refname_available_dir(
2023 refname, extras, skip,
2024 get_loose_refs(refs), err))
0568c8e9 2025 strbuf_addf(err, "unable to resolve reference '%s': %s",
7a418f3a 2026 refname, strerror(last_errno));
7bd9bcf3
MH
2027
2028 goto error_return;
2029 }
2859dcd4 2030
7bd9bcf3
MH
2031 /*
2032 * If the ref did not exist and we are creating it, make sure
2033 * there is no existing packed ref whose name begins with our
2034 * refname, nor a packed ref whose name is a proper prefix of
2035 * our refname.
2036 */
2037 if (is_null_oid(&lock->old_oid) &&
2038 verify_refname_available_dir(refname, extras, skip,
00eebe35
MH
2039 get_packed_refs(refs),
2040 err)) {
7bd9bcf3
MH
2041 last_errno = ENOTDIR;
2042 goto error_return;
2043 }
2044
2045 lock->lk = xcalloc(1, sizeof(struct lock_file));
2046
7bd9bcf3 2047 lock->ref_name = xstrdup(refname);
7bd9bcf3
MH
2048
2049 retry:
2050 switch (safe_create_leading_directories_const(ref_file.buf)) {
2051 case SCLD_OK:
2052 break; /* success */
2053 case SCLD_VANISHED:
2054 if (--attempts_remaining > 0)
2055 goto retry;
2056 /* fall through */
2057 default:
2058 last_errno = errno;
0568c8e9 2059 strbuf_addf(err, "unable to create directory for '%s'",
7bd9bcf3
MH
2060 ref_file.buf);
2061 goto error_return;
2062 }
2063
2064 if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {
2065 last_errno = errno;
2066 if (errno == ENOENT && --attempts_remaining > 0)
2067 /*
2068 * Maybe somebody just deleted one of the
2069 * directories leading to ref_file. Try
2070 * again:
2071 */
2072 goto retry;
2073 else {
2074 unable_to_lock_message(ref_file.buf, errno, err);
2075 goto error_return;
2076 }
2077 }
6294dcb4 2078 if (verify_lock(lock, old_sha1, mustexist, err)) {
7bd9bcf3
MH
2079 last_errno = errno;
2080 goto error_return;
2081 }
2082 goto out;
2083
2084 error_return:
2085 unlock_ref(lock);
2086 lock = NULL;
2087
2088 out:
2089 strbuf_release(&ref_file);
7bd9bcf3
MH
2090 errno = last_errno;
2091 return lock;
2092}
2093
2094/*
2095 * Write an entry to the packed-refs file for the specified refname.
2096 * If peeled is non-NULL, write it as the entry's peeled value.
2097 */
2098static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2099 unsigned char *peeled)
2100{
2101 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2102 if (peeled)
2103 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2104}
2105
2106/*
2107 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2108 */
2109static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2110{
2111 enum peel_status peel_status = peel_entry(entry, 0);
2112
2113 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2114 error("internal error: %s is not a valid packed reference!",
2115 entry->name);
2116 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2117 peel_status == PEEL_PEELED ?
2118 entry->u.value.peeled.hash : NULL);
2119 return 0;
2120}
2121
2122/*
2123 * Lock the packed-refs file for writing. Flags is passed to
2124 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2125 * errno appropriately and return a nonzero value.
2126 */
49c0df6a 2127static int lock_packed_refs(struct files_ref_store *refs, int flags)
7bd9bcf3
MH
2128{
2129 static int timeout_configured = 0;
2130 static int timeout_value = 1000;
7bd9bcf3
MH
2131 struct packed_ref_cache *packed_ref_cache;
2132
49c0df6a
MH
2133 assert_main_repository(&refs->base, "lock_packed_refs");
2134
7bd9bcf3
MH
2135 if (!timeout_configured) {
2136 git_config_get_int("core.packedrefstimeout", &timeout_value);
2137 timeout_configured = 1;
2138 }
2139
2140 if (hold_lock_file_for_update_timeout(
2141 &packlock, git_path("packed-refs"),
2142 flags, timeout_value) < 0)
2143 return -1;
2144 /*
2145 * Get the current packed-refs while holding the lock. If the
2146 * packed-refs file has been modified since we last read it,
2147 * this will automatically invalidate the cache and re-read
2148 * the packed-refs file.
2149 */
00eebe35 2150 packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
2151 packed_ref_cache->lock = &packlock;
2152 /* Increment the reference count to prevent it from being freed: */
2153 acquire_packed_ref_cache(packed_ref_cache);
2154 return 0;
2155}
2156
2157/*
2158 * Write the current version of the packed refs cache from memory to
2159 * disk. The packed-refs file must already be locked for writing (see
2160 * lock_packed_refs()). Return zero on success. On errors, set errno
2161 * and return a nonzero value
2162 */
49c0df6a 2163static int commit_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2164{
2165 struct packed_ref_cache *packed_ref_cache =
00eebe35 2166 get_packed_ref_cache(refs);
7bd9bcf3
MH
2167 int error = 0;
2168 int save_errno = 0;
2169 FILE *out;
2170
49c0df6a
MH
2171 assert_main_repository(&refs->base, "commit_packed_refs");
2172
7bd9bcf3
MH
2173 if (!packed_ref_cache->lock)
2174 die("internal error: packed-refs not locked");
2175
2176 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2177 if (!out)
2178 die_errno("unable to fdopen packed-refs descriptor");
2179
2180 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2181 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2182 0, write_packed_entry_fn, out);
2183
2184 if (commit_lock_file(packed_ref_cache->lock)) {
2185 save_errno = errno;
2186 error = -1;
2187 }
2188 packed_ref_cache->lock = NULL;
2189 release_packed_ref_cache(packed_ref_cache);
2190 errno = save_errno;
2191 return error;
2192}
2193
2194/*
2195 * Rollback the lockfile for the packed-refs file, and discard the
2196 * in-memory packed reference cache. (The packed-refs file will be
2197 * read anew if it is needed again after this function is called.)
2198 */
49c0df6a 2199static void rollback_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2200{
2201 struct packed_ref_cache *packed_ref_cache =
00eebe35 2202 get_packed_ref_cache(refs);
7bd9bcf3 2203
49c0df6a
MH
2204 assert_main_repository(&refs->base, "rollback_packed_refs");
2205
7bd9bcf3
MH
2206 if (!packed_ref_cache->lock)
2207 die("internal error: packed-refs not locked");
2208 rollback_lock_file(packed_ref_cache->lock);
2209 packed_ref_cache->lock = NULL;
2210 release_packed_ref_cache(packed_ref_cache);
00eebe35 2211 clear_packed_ref_cache(refs);
7bd9bcf3
MH
2212}
2213
2214struct ref_to_prune {
2215 struct ref_to_prune *next;
2216 unsigned char sha1[20];
2217 char name[FLEX_ARRAY];
2218};
2219
2220struct pack_refs_cb_data {
2221 unsigned int flags;
2222 struct ref_dir *packed_refs;
2223 struct ref_to_prune *ref_to_prune;
2224};
2225
2226/*
2227 * An each_ref_entry_fn that is run over loose references only. If
2228 * the loose reference can be packed, add an entry in the packed ref
2229 * cache. If the reference should be pruned, also add it to
2230 * ref_to_prune in the pack_refs_cb_data.
2231 */
2232static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2233{
2234 struct pack_refs_cb_data *cb = cb_data;
2235 enum peel_status peel_status;
2236 struct ref_entry *packed_entry;
2237 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2238
2239 /* Do not pack per-worktree refs: */
2240 if (ref_type(entry->name) != REF_TYPE_NORMAL)
2241 return 0;
2242
2243 /* ALWAYS pack tags */
2244 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2245 return 0;
2246
2247 /* Do not pack symbolic or broken refs: */
ffeef642 2248 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))
7bd9bcf3
MH
2249 return 0;
2250
2251 /* Add a packed ref cache entry equivalent to the loose entry. */
2252 peel_status = peel_entry(entry, 1);
2253 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2254 die("internal error peeling reference %s (%s)",
2255 entry->name, oid_to_hex(&entry->u.value.oid));
2256 packed_entry = find_ref(cb->packed_refs, entry->name);
2257 if (packed_entry) {
2258 /* Overwrite existing packed entry with info from loose entry */
2259 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2260 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2261 } else {
2262 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2263 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2264 add_ref(cb->packed_refs, packed_entry);
2265 }
2266 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2267
2268 /* Schedule the loose reference for pruning if requested. */
2269 if ((cb->flags & PACK_REFS_PRUNE)) {
96ffc06f
JK
2270 struct ref_to_prune *n;
2271 FLEX_ALLOC_STR(n, name, entry->name);
7bd9bcf3 2272 hashcpy(n->sha1, entry->u.value.oid.hash);
7bd9bcf3
MH
2273 n->next = cb->ref_to_prune;
2274 cb->ref_to_prune = n;
2275 }
2276 return 0;
2277}
2278
2279/*
2280 * Remove empty parents, but spare refs/ and immediate subdirs.
2281 * Note: munges *name.
2282 */
2283static void try_remove_empty_parents(char *name)
2284{
2285 char *p, *q;
2286 int i;
2287 p = name;
2288 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2289 while (*p && *p != '/')
2290 p++;
2291 /* tolerate duplicate slashes; see check_refname_format() */
2292 while (*p == '/')
2293 p++;
2294 }
2295 for (q = p; *q; q++)
2296 ;
2297 while (1) {
2298 while (q > p && *q != '/')
2299 q--;
2300 while (q > p && *(q-1) == '/')
2301 q--;
2302 if (q == p)
2303 break;
2304 *q = '\0';
2305 if (rmdir(git_path("%s", name)))
2306 break;
2307 }
2308}
2309
2310/* make sure nobody touched the ref, and unlink */
2311static void prune_ref(struct ref_to_prune *r)
2312{
2313 struct ref_transaction *transaction;
2314 struct strbuf err = STRBUF_INIT;
2315
2316 if (check_refname_format(r->name, 0))
2317 return;
2318
2319 transaction = ref_transaction_begin(&err);
2320 if (!transaction ||
2321 ref_transaction_delete(transaction, r->name, r->sha1,
c52ce248 2322 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
7bd9bcf3
MH
2323 ref_transaction_commit(transaction, &err)) {
2324 ref_transaction_free(transaction);
2325 error("%s", err.buf);
2326 strbuf_release(&err);
2327 return;
2328 }
2329 ref_transaction_free(transaction);
2330 strbuf_release(&err);
2331 try_remove_empty_parents(r->name);
2332}
2333
2334static void prune_refs(struct ref_to_prune *r)
2335{
2336 while (r) {
2337 prune_ref(r);
2338 r = r->next;
2339 }
2340}
2341
8231527e 2342static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
7bd9bcf3 2343{
00eebe35 2344 struct files_ref_store *refs =
8231527e 2345 files_downcast(ref_store, 0, "pack_refs");
7bd9bcf3
MH
2346 struct pack_refs_cb_data cbdata;
2347
2348 memset(&cbdata, 0, sizeof(cbdata));
2349 cbdata.flags = flags;
2350
49c0df6a 2351 lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
00eebe35 2352 cbdata.packed_refs = get_packed_refs(refs);
7bd9bcf3 2353
00eebe35 2354 do_for_each_entry_in_dir(get_loose_refs(refs), 0,
7bd9bcf3
MH
2355 pack_if_possible_fn, &cbdata);
2356
49c0df6a 2357 if (commit_packed_refs(refs))
7bd9bcf3
MH
2358 die_errno("unable to overwrite old ref-pack file");
2359
2360 prune_refs(cbdata.ref_to_prune);
2361 return 0;
2362}
2363
2364/*
2365 * Rewrite the packed-refs file, omitting any refs listed in
2366 * 'refnames'. On error, leave packed-refs unchanged, write an error
2367 * message to 'err', and return a nonzero value.
2368 *
2369 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2370 */
0a95ac5f
MH
2371static int repack_without_refs(struct files_ref_store *refs,
2372 struct string_list *refnames, struct strbuf *err)
7bd9bcf3
MH
2373{
2374 struct ref_dir *packed;
2375 struct string_list_item *refname;
2376 int ret, needs_repacking = 0, removed = 0;
2377
0a95ac5f 2378 assert_main_repository(&refs->base, "repack_without_refs");
7bd9bcf3
MH
2379 assert(err);
2380
2381 /* Look for a packed ref */
2382 for_each_string_list_item(refname, refnames) {
f0d21efc 2383 if (get_packed_ref(refs, refname->string)) {
7bd9bcf3
MH
2384 needs_repacking = 1;
2385 break;
2386 }
2387 }
2388
2389 /* Avoid locking if we have nothing to do */
2390 if (!needs_repacking)
2391 return 0; /* no refname exists in packed refs */
2392
49c0df6a 2393 if (lock_packed_refs(refs, 0)) {
7bd9bcf3
MH
2394 unable_to_lock_message(git_path("packed-refs"), errno, err);
2395 return -1;
2396 }
00eebe35 2397 packed = get_packed_refs(refs);
7bd9bcf3
MH
2398
2399 /* Remove refnames from the cache */
2400 for_each_string_list_item(refname, refnames)
2401 if (remove_entry(packed, refname->string) != -1)
2402 removed = 1;
2403 if (!removed) {
2404 /*
2405 * All packed entries disappeared while we were
2406 * acquiring the lock.
2407 */
49c0df6a 2408 rollback_packed_refs(refs);
7bd9bcf3
MH
2409 return 0;
2410 }
2411
2412 /* Write what remains */
49c0df6a 2413 ret = commit_packed_refs(refs);
7bd9bcf3
MH
2414 if (ret)
2415 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2416 strerror(errno));
2417 return ret;
2418}
2419
2420static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2421{
2422 assert(err);
2423
2424 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2425 /*
2426 * loose. The loose file name is the same as the
2427 * lockfile name, minus ".lock":
2428 */
2429 char *loose_filename = get_locked_file_path(lock->lk);
2430 int res = unlink_or_msg(loose_filename, err);
2431 free(loose_filename);
2432 if (res)
2433 return 1;
2434 }
2435 return 0;
2436}
2437
a27dcf89
DT
2438static int files_delete_refs(struct ref_store *ref_store,
2439 struct string_list *refnames, unsigned int flags)
7bd9bcf3 2440{
0a95ac5f 2441 struct files_ref_store *refs =
a27dcf89 2442 files_downcast(ref_store, 0, "delete_refs");
7bd9bcf3
MH
2443 struct strbuf err = STRBUF_INIT;
2444 int i, result = 0;
2445
2446 if (!refnames->nr)
2447 return 0;
2448
0a95ac5f 2449 result = repack_without_refs(refs, refnames, &err);
7bd9bcf3
MH
2450 if (result) {
2451 /*
2452 * If we failed to rewrite the packed-refs file, then
2453 * it is unsafe to try to remove loose refs, because
2454 * doing so might expose an obsolete packed value for
2455 * a reference that might even point at an object that
2456 * has been garbage collected.
2457 */
2458 if (refnames->nr == 1)
2459 error(_("could not delete reference %s: %s"),
2460 refnames->items[0].string, err.buf);
2461 else
2462 error(_("could not delete references: %s"), err.buf);
2463
2464 goto out;
2465 }
2466
2467 for (i = 0; i < refnames->nr; i++) {
2468 const char *refname = refnames->items[i].string;
2469
c5f04ddd 2470 if (delete_ref(refname, NULL, flags))
7bd9bcf3
MH
2471 result |= error(_("could not remove reference %s"), refname);
2472 }
2473
2474out:
2475 strbuf_release(&err);
2476 return result;
2477}
2478
2479/*
2480 * People using contrib's git-new-workdir have .git/logs/refs ->
2481 * /some/other/path/.git/logs/refs, and that may live on another device.
2482 *
2483 * IOW, to avoid cross device rename errors, the temporary renamed log must
2484 * live into logs/refs.
2485 */
2486#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2487
2488static int rename_tmp_log(const char *newrefname)
2489{
2490 int attempts_remaining = 4;
2491 struct strbuf path = STRBUF_INIT;
2492 int ret = -1;
2493
2494 retry:
2495 strbuf_reset(&path);
2496 strbuf_git_path(&path, "logs/%s", newrefname);
2497 switch (safe_create_leading_directories_const(path.buf)) {
2498 case SCLD_OK:
2499 break; /* success */
2500 case SCLD_VANISHED:
2501 if (--attempts_remaining > 0)
2502 goto retry;
2503 /* fall through */
2504 default:
2505 error("unable to create directory for %s", newrefname);
2506 goto out;
2507 }
2508
2509 if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
2510 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2511 /*
2512 * rename(a, b) when b is an existing
2513 * directory ought to result in ISDIR, but
2514 * Solaris 5.8 gives ENOTDIR. Sheesh.
2515 */
2516 if (remove_empty_directories(&path)) {
2517 error("Directory not empty: logs/%s", newrefname);
2518 goto out;
2519 }
2520 goto retry;
2521 } else if (errno == ENOENT && --attempts_remaining > 0) {
2522 /*
2523 * Maybe another process just deleted one of
2524 * the directories in the path to newrefname.
2525 * Try again from the beginning.
2526 */
2527 goto retry;
2528 } else {
2529 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2530 newrefname, strerror(errno));
2531 goto out;
2532 }
2533 }
2534 ret = 0;
2535out:
2536 strbuf_release(&path);
2537 return ret;
2538}
2539
62665823
MH
2540static int files_verify_refname_available(struct ref_store *ref_store,
2541 const char *newname,
2542 const struct string_list *extras,
2543 const struct string_list *skip,
2544 struct strbuf *err)
7bd9bcf3 2545{
00eebe35 2546 struct files_ref_store *refs =
62665823 2547 files_downcast(ref_store, 1, "verify_refname_available");
00eebe35
MH
2548 struct ref_dir *packed_refs = get_packed_refs(refs);
2549 struct ref_dir *loose_refs = get_loose_refs(refs);
7bd9bcf3
MH
2550
2551 if (verify_refname_available_dir(newname, extras, skip,
2552 packed_refs, err) ||
2553 verify_refname_available_dir(newname, extras, skip,
2554 loose_refs, err))
2555 return -1;
2556
2557 return 0;
2558}
2559
7bd9bcf3
MH
2560static int write_ref_to_lockfile(struct ref_lock *lock,
2561 const unsigned char *sha1, struct strbuf *err);
f18a7892
MH
2562static int commit_ref_update(struct files_ref_store *refs,
2563 struct ref_lock *lock,
7bd9bcf3 2564 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2565 struct strbuf *err);
7bd9bcf3 2566
9b6b40d9
DT
2567static int files_rename_ref(struct ref_store *ref_store,
2568 const char *oldrefname, const char *newrefname,
2569 const char *logmsg)
7bd9bcf3 2570{
9b6b40d9
DT
2571 struct files_ref_store *refs =
2572 files_downcast(ref_store, 0, "rename_ref");
7bd9bcf3
MH
2573 unsigned char sha1[20], orig_sha1[20];
2574 int flag = 0, logmoved = 0;
2575 struct ref_lock *lock;
2576 struct stat loginfo;
2577 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
7bd9bcf3
MH
2578 struct strbuf err = STRBUF_INIT;
2579
2580 if (log && S_ISLNK(loginfo.st_mode))
2581 return error("reflog for %s is a symlink", oldrefname);
2582
12fd3496
DT
2583 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2584 orig_sha1, &flag))
e711b1af
MH
2585 return error("refname %s not found", oldrefname);
2586
7bd9bcf3
MH
2587 if (flag & REF_ISSYMREF)
2588 return error("refname %s is a symbolic ref, renaming it is not supported",
2589 oldrefname);
7bd9bcf3
MH
2590 if (!rename_ref_available(oldrefname, newrefname))
2591 return 1;
2592
2593 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2594 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2595 oldrefname, strerror(errno));
2596
2597 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2598 error("unable to delete old %s", oldrefname);
2599 goto rollback;
2600 }
2601
12fd3496
DT
2602 /*
2603 * Since we are doing a shallow lookup, sha1 is not the
2604 * correct value to pass to delete_ref as old_sha1. But that
2605 * doesn't matter, because an old_sha1 check wouldn't add to
2606 * the safety anyway; we want to delete the reference whatever
2607 * its current value.
2608 */
2609 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2610 sha1, NULL) &&
2611 delete_ref(newrefname, NULL, REF_NODEREF)) {
7bd9bcf3
MH
2612 if (errno==EISDIR) {
2613 struct strbuf path = STRBUF_INIT;
2614 int result;
2615
2616 strbuf_git_path(&path, "%s", newrefname);
2617 result = remove_empty_directories(&path);
2618 strbuf_release(&path);
2619
2620 if (result) {
2621 error("Directory not empty: %s", newrefname);
2622 goto rollback;
2623 }
2624 } else {
2625 error("unable to delete existing %s", newrefname);
2626 goto rollback;
2627 }
2628 }
2629
2630 if (log && rename_tmp_log(newrefname))
2631 goto rollback;
2632
2633 logmoved = log;
2634
7eb27cdf
MH
2635 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
2636 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
2637 if (!lock) {
2638 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2639 strbuf_release(&err);
2640 goto rollback;
2641 }
2642 hashcpy(lock->old_oid.hash, orig_sha1);
2643
2644 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 2645 commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {
7bd9bcf3
MH
2646 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
2647 strbuf_release(&err);
2648 goto rollback;
2649 }
2650
2651 return 0;
2652
2653 rollback:
7eb27cdf
MH
2654 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
2655 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
2656 if (!lock) {
2657 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2658 strbuf_release(&err);
2659 goto rollbacklog;
2660 }
2661
2662 flag = log_all_ref_updates;
2663 log_all_ref_updates = 0;
2664 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 2665 commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {
7bd9bcf3
MH
2666 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
2667 strbuf_release(&err);
2668 }
2669 log_all_ref_updates = flag;
2670
2671 rollbacklog:
2672 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2673 error("unable to restore logfile %s from %s: %s",
2674 oldrefname, newrefname, strerror(errno));
2675 if (!logmoved && log &&
2676 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2677 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2678 oldrefname, strerror(errno));
2679
2680 return 1;
2681}
2682
2683static int close_ref(struct ref_lock *lock)
2684{
2685 if (close_lock_file(lock->lk))
2686 return -1;
2687 return 0;
2688}
2689
2690static int commit_ref(struct ref_lock *lock)
2691{
5387c0d8
MH
2692 char *path = get_locked_file_path(lock->lk);
2693 struct stat st;
2694
2695 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
2696 /*
2697 * There is a directory at the path we want to rename
2698 * the lockfile to. Hopefully it is empty; try to
2699 * delete it.
2700 */
2701 size_t len = strlen(path);
2702 struct strbuf sb_path = STRBUF_INIT;
2703
2704 strbuf_attach(&sb_path, path, len, len);
2705
2706 /*
2707 * If this fails, commit_lock_file() will also fail
2708 * and will report the problem.
2709 */
2710 remove_empty_directories(&sb_path);
2711 strbuf_release(&sb_path);
2712 } else {
2713 free(path);
2714 }
2715
7bd9bcf3
MH
2716 if (commit_lock_file(lock->lk))
2717 return -1;
2718 return 0;
2719}
2720
2721/*
2722 * Create a reflog for a ref. If force_create = 0, the reflog will
2723 * only be created for certain refs (those for which
2724 * should_autocreate_reflog returns non-zero. Otherwise, create it
2725 * regardless of the ref name. Fill in *err and return -1 on failure.
2726 */
2727static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
2728{
2729 int logfd, oflags = O_APPEND | O_WRONLY;
2730
2731 strbuf_git_path(logfile, "logs/%s", refname);
2732 if (force_create || should_autocreate_reflog(refname)) {
2733 if (safe_create_leading_directories(logfile->buf) < 0) {
0568c8e9 2734 strbuf_addf(err, "unable to create directory for '%s': "
7bd9bcf3
MH
2735 "%s", logfile->buf, strerror(errno));
2736 return -1;
2737 }
2738 oflags |= O_CREAT;
2739 }
2740
2741 logfd = open(logfile->buf, oflags, 0666);
2742 if (logfd < 0) {
2743 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
2744 return 0;
2745
2746 if (errno == EISDIR) {
2747 if (remove_empty_directories(logfile)) {
0568c8e9 2748 strbuf_addf(err, "there are still logs under "
7bd9bcf3
MH
2749 "'%s'", logfile->buf);
2750 return -1;
2751 }
2752 logfd = open(logfile->buf, oflags, 0666);
2753 }
2754
2755 if (logfd < 0) {
0568c8e9 2756 strbuf_addf(err, "unable to append to '%s': %s",
7bd9bcf3
MH
2757 logfile->buf, strerror(errno));
2758 return -1;
2759 }
2760 }
2761
2762 adjust_shared_perm(logfile->buf);
2763 close(logfd);
2764 return 0;
2765}
2766
2767
e3688bd6
DT
2768static int files_create_reflog(struct ref_store *ref_store,
2769 const char *refname, int force_create,
2770 struct strbuf *err)
7bd9bcf3
MH
2771{
2772 int ret;
2773 struct strbuf sb = STRBUF_INIT;
2774
e3688bd6
DT
2775 /* Check validity (but we don't need the result): */
2776 files_downcast(ref_store, 0, "create_reflog");
2777
7bd9bcf3
MH
2778 ret = log_ref_setup(refname, &sb, err, force_create);
2779 strbuf_release(&sb);
2780 return ret;
2781}
2782
2783static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2784 const unsigned char *new_sha1,
2785 const char *committer, const char *msg)
2786{
2787 int msglen, written;
2788 unsigned maxlen, len;
2789 char *logrec;
2790
2791 msglen = msg ? strlen(msg) : 0;
2792 maxlen = strlen(committer) + msglen + 100;
2793 logrec = xmalloc(maxlen);
2794 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2795 sha1_to_hex(old_sha1),
2796 sha1_to_hex(new_sha1),
2797 committer);
2798 if (msglen)
2799 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2800
2801 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2802 free(logrec);
2803 if (written != len)
2804 return -1;
2805
2806 return 0;
2807}
2808
2809static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
2810 const unsigned char *new_sha1, const char *msg,
2811 struct strbuf *logfile, int flags,
2812 struct strbuf *err)
2813{
2814 int logfd, result, oflags = O_APPEND | O_WRONLY;
2815
2816 if (log_all_ref_updates < 0)
2817 log_all_ref_updates = !is_bare_repository();
2818
2819 result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
2820
2821 if (result)
2822 return result;
2823
2824 logfd = open(logfile->buf, oflags);
2825 if (logfd < 0)
2826 return 0;
2827 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2828 git_committer_info(0), msg);
2829 if (result) {
0568c8e9 2830 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,
7bd9bcf3
MH
2831 strerror(errno));
2832 close(logfd);
2833 return -1;
2834 }
2835 if (close(logfd)) {
0568c8e9 2836 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,
7bd9bcf3
MH
2837 strerror(errno));
2838 return -1;
2839 }
2840 return 0;
2841}
2842
2843static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2844 const unsigned char *new_sha1, const char *msg,
2845 int flags, struct strbuf *err)
5f3c3a4e
DT
2846{
2847 return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
2848 err);
2849}
2850
2851int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
2852 const unsigned char *new_sha1, const char *msg,
2853 int flags, struct strbuf *err)
7bd9bcf3
MH
2854{
2855 struct strbuf sb = STRBUF_INIT;
2856 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
2857 err);
2858 strbuf_release(&sb);
2859 return ret;
2860}
2861
2862/*
2863 * Write sha1 into the open lockfile, then close the lockfile. On
2864 * errors, rollback the lockfile, fill in *err and
2865 * return -1.
2866 */
2867static int write_ref_to_lockfile(struct ref_lock *lock,
2868 const unsigned char *sha1, struct strbuf *err)
2869{
2870 static char term = '\n';
2871 struct object *o;
2872 int fd;
2873
2874 o = parse_object(sha1);
2875 if (!o) {
2876 strbuf_addf(err,
0568c8e9 2877 "trying to write ref '%s' with nonexistent object %s",
7bd9bcf3
MH
2878 lock->ref_name, sha1_to_hex(sha1));
2879 unlock_ref(lock);
2880 return -1;
2881 }
2882 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2883 strbuf_addf(err,
0568c8e9 2884 "trying to write non-commit object %s to branch '%s'",
7bd9bcf3
MH
2885 sha1_to_hex(sha1), lock->ref_name);
2886 unlock_ref(lock);
2887 return -1;
2888 }
2889 fd = get_lock_file_fd(lock->lk);
2890 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
2891 write_in_full(fd, &term, 1) != 1 ||
2892 close_ref(lock) < 0) {
2893 strbuf_addf(err,
0568c8e9 2894 "couldn't write '%s'", get_lock_file_path(lock->lk));
7bd9bcf3
MH
2895 unlock_ref(lock);
2896 return -1;
2897 }
2898 return 0;
2899}
2900
2901/*
2902 * Commit a change to a loose reference that has already been written
2903 * to the loose reference lockfile. Also update the reflogs if
2904 * necessary, using the specified lockmsg (which can be NULL).
2905 */
f18a7892
MH
2906static int commit_ref_update(struct files_ref_store *refs,
2907 struct ref_lock *lock,
7bd9bcf3 2908 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2909 struct strbuf *err)
7bd9bcf3 2910{
f18a7892 2911 assert_main_repository(&refs->base, "commit_ref_update");
00eebe35
MH
2912
2913 clear_loose_ref_cache(refs);
7a418f3a 2914 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, 0, err)) {
7bd9bcf3 2915 char *old_msg = strbuf_detach(err, NULL);
0568c8e9 2916 strbuf_addf(err, "cannot update the ref '%s': %s",
7bd9bcf3
MH
2917 lock->ref_name, old_msg);
2918 free(old_msg);
2919 unlock_ref(lock);
2920 return -1;
2921 }
7a418f3a
MH
2922
2923 if (strcmp(lock->ref_name, "HEAD") != 0) {
7bd9bcf3
MH
2924 /*
2925 * Special hack: If a branch is updated directly and HEAD
2926 * points to it (may happen on the remote side of a push
2927 * for example) then logically the HEAD reflog should be
2928 * updated too.
2929 * A generic solution implies reverse symref information,
2930 * but finding all symrefs pointing to the given branch
2931 * would be rather costly for this rare event (the direct
2932 * update of a branch) to be worth it. So let's cheat and
2933 * check with HEAD only which should cover 99% of all usage
2934 * scenarios (even 100% of the default ones).
2935 */
2936 unsigned char head_sha1[20];
2937 int head_flag;
2938 const char *head_ref;
7a418f3a 2939
7bd9bcf3
MH
2940 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
2941 head_sha1, &head_flag);
2942 if (head_ref && (head_flag & REF_ISSYMREF) &&
2943 !strcmp(head_ref, lock->ref_name)) {
2944 struct strbuf log_err = STRBUF_INIT;
2945 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
2946 logmsg, 0, &log_err)) {
2947 error("%s", log_err.buf);
2948 strbuf_release(&log_err);
2949 }
2950 }
2951 }
7a418f3a 2952
5d9b2de4 2953 if (commit_ref(lock)) {
0568c8e9 2954 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
7bd9bcf3
MH
2955 unlock_ref(lock);
2956 return -1;
2957 }
2958
2959 unlock_ref(lock);
2960 return 0;
2961}
2962
370e5ad6 2963static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 2964{
370e5ad6 2965 int ret = -1;
7bd9bcf3 2966#ifndef NO_SYMLINK_HEAD
370e5ad6
JK
2967 char *ref_path = get_locked_file_path(lock->lk);
2968 unlink(ref_path);
2969 ret = symlink(target, ref_path);
2970 free(ref_path);
2971
2972 if (ret)
7bd9bcf3 2973 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 2974#endif
370e5ad6
JK
2975 return ret;
2976}
7bd9bcf3 2977
370e5ad6
JK
2978static void update_symref_reflog(struct ref_lock *lock, const char *refname,
2979 const char *target, const char *logmsg)
2980{
2981 struct strbuf err = STRBUF_INIT;
2982 unsigned char new_sha1[20];
b9badadd 2983 if (logmsg && !read_ref(target, new_sha1) &&
370e5ad6 2984 log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
7bd9bcf3
MH
2985 error("%s", err.buf);
2986 strbuf_release(&err);
2987 }
370e5ad6 2988}
7bd9bcf3 2989
370e5ad6
JK
2990static int create_symref_locked(struct ref_lock *lock, const char *refname,
2991 const char *target, const char *logmsg)
2992{
2993 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
2994 update_symref_reflog(lock, refname, target, logmsg);
2995 return 0;
2996 }
2997
2998 if (!fdopen_lock_file(lock->lk, "w"))
2999 return error("unable to fdopen %s: %s",
3000 lock->lk->tempfile.filename.buf, strerror(errno));
3001
396da8f7
JK
3002 update_symref_reflog(lock, refname, target, logmsg);
3003
370e5ad6
JK
3004 /* no error check; commit_ref will check ferror */
3005 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
3006 if (commit_ref(lock) < 0)
3007 return error("unable to write symref for %s: %s", refname,
3008 strerror(errno));
7bd9bcf3
MH
3009 return 0;
3010}
3011
284689ba
MH
3012static int files_create_symref(struct ref_store *ref_store,
3013 const char *refname, const char *target,
3014 const char *logmsg)
370e5ad6 3015{
7eb27cdf
MH
3016 struct files_ref_store *refs =
3017 files_downcast(ref_store, 0, "create_symref");
370e5ad6
JK
3018 struct strbuf err = STRBUF_INIT;
3019 struct ref_lock *lock;
3020 int ret;
3021
7eb27cdf
MH
3022 lock = lock_ref_sha1_basic(refs, refname, NULL,
3023 NULL, NULL, REF_NODEREF, NULL,
370e5ad6
JK
3024 &err);
3025 if (!lock) {
3026 error("%s", err.buf);
3027 strbuf_release(&err);
3028 return -1;
3029 }
3030
3031 ret = create_symref_locked(lock, refname, target, logmsg);
3032 unlock_ref(lock);
3033 return ret;
3034}
3035
2233066e
KY
3036int set_worktree_head_symref(const char *gitdir, const char *target)
3037{
3038 static struct lock_file head_lock;
3039 struct ref_lock *lock;
2233066e
KY
3040 struct strbuf head_path = STRBUF_INIT;
3041 const char *head_rel;
3042 int ret;
3043
3044 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));
3045 if (hold_lock_file_for_update(&head_lock, head_path.buf,
3046 LOCK_NO_DEREF) < 0) {
18eb3a9c
KY
3047 struct strbuf err = STRBUF_INIT;
3048 unable_to_lock_message(head_path.buf, errno, &err);
2233066e
KY
3049 error("%s", err.buf);
3050 strbuf_release(&err);
3051 strbuf_release(&head_path);
3052 return -1;
3053 }
3054
3055 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for
3056 linked trees */
3057 head_rel = remove_leading_path(head_path.buf,
3058 absolute_path(get_git_common_dir()));
3059 /* to make use of create_symref_locked(), initialize ref_lock */
3060 lock = xcalloc(1, sizeof(struct ref_lock));
3061 lock->lk = &head_lock;
3062 lock->ref_name = xstrdup(head_rel);
2233066e
KY
3063
3064 ret = create_symref_locked(lock, head_rel, target, NULL);
3065
3066 unlock_ref(lock); /* will free lock */
3067 strbuf_release(&head_path);
3068 return ret;
3069}
3070
e3688bd6
DT
3071static int files_reflog_exists(struct ref_store *ref_store,
3072 const char *refname)
7bd9bcf3
MH
3073{
3074 struct stat st;
3075
e3688bd6
DT
3076 /* Check validity (but we don't need the result): */
3077 files_downcast(ref_store, 0, "reflog_exists");
3078
7bd9bcf3
MH
3079 return !lstat(git_path("logs/%s", refname), &st) &&
3080 S_ISREG(st.st_mode);
3081}
3082
e3688bd6
DT
3083static int files_delete_reflog(struct ref_store *ref_store,
3084 const char *refname)
7bd9bcf3 3085{
e3688bd6
DT
3086 /* Check validity (but we don't need the result): */
3087 files_downcast(ref_store, 0, "delete_reflog");
3088
7bd9bcf3
MH
3089 return remove_path(git_path("logs/%s", refname));
3090}
3091
3092static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3093{
3094 unsigned char osha1[20], nsha1[20];
3095 char *email_end, *message;
3096 unsigned long timestamp;
3097 int tz;
3098
3099 /* old SP new SP name <email> SP time TAB msg LF */
3100 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3101 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3102 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3103 !(email_end = strchr(sb->buf + 82, '>')) ||
3104 email_end[1] != ' ' ||
3105 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3106 !message || message[0] != ' ' ||
3107 (message[1] != '+' && message[1] != '-') ||
3108 !isdigit(message[2]) || !isdigit(message[3]) ||
3109 !isdigit(message[4]) || !isdigit(message[5]))
3110 return 0; /* corrupt? */
3111 email_end[1] = '\0';
3112 tz = strtol(message + 1, NULL, 10);
3113 if (message[6] != '\t')
3114 message += 6;
3115 else
3116 message += 7;
3117 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3118}
3119
3120static char *find_beginning_of_line(char *bob, char *scan)
3121{
3122 while (bob < scan && *(--scan) != '\n')
3123 ; /* keep scanning backwards */
3124 /*
3125 * Return either beginning of the buffer, or LF at the end of
3126 * the previous line.
3127 */
3128 return scan;
3129}
3130
e3688bd6
DT
3131static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
3132 const char *refname,
3133 each_reflog_ent_fn fn,
3134 void *cb_data)
7bd9bcf3
MH
3135{
3136 struct strbuf sb = STRBUF_INIT;
3137 FILE *logfp;
3138 long pos;
3139 int ret = 0, at_tail = 1;
3140
e3688bd6
DT
3141 /* Check validity (but we don't need the result): */
3142 files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
3143
7bd9bcf3
MH
3144 logfp = fopen(git_path("logs/%s", refname), "r");
3145 if (!logfp)
3146 return -1;
3147
3148 /* Jump to the end */
3149 if (fseek(logfp, 0, SEEK_END) < 0)
3150 return error("cannot seek back reflog for %s: %s",
3151 refname, strerror(errno));
3152 pos = ftell(logfp);
3153 while (!ret && 0 < pos) {
3154 int cnt;
3155 size_t nread;
3156 char buf[BUFSIZ];
3157 char *endp, *scanp;
3158
3159 /* Fill next block from the end */
3160 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3161 if (fseek(logfp, pos - cnt, SEEK_SET))
3162 return error("cannot seek back reflog for %s: %s",
3163 refname, strerror(errno));
3164 nread = fread(buf, cnt, 1, logfp);
3165 if (nread != 1)
3166 return error("cannot read %d bytes from reflog for %s: %s",
3167 cnt, refname, strerror(errno));
3168 pos -= cnt;
3169
3170 scanp = endp = buf + cnt;
3171 if (at_tail && scanp[-1] == '\n')
3172 /* Looking at the final LF at the end of the file */
3173 scanp--;
3174 at_tail = 0;
3175
3176 while (buf < scanp) {
3177 /*
3178 * terminating LF of the previous line, or the beginning
3179 * of the buffer.
3180 */
3181 char *bp;
3182
3183 bp = find_beginning_of_line(buf, scanp);
3184
3185 if (*bp == '\n') {
3186 /*
3187 * The newline is the end of the previous line,
3188 * so we know we have complete line starting
3189 * at (bp + 1). Prefix it onto any prior data
3190 * we collected for the line and process it.
3191 */
3192 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3193 scanp = bp;
3194 endp = bp + 1;
3195 ret = show_one_reflog_ent(&sb, fn, cb_data);
3196 strbuf_reset(&sb);
3197 if (ret)
3198 break;
3199 } else if (!pos) {
3200 /*
3201 * We are at the start of the buffer, and the
3202 * start of the file; there is no previous
3203 * line, and we have everything for this one.
3204 * Process it, and we can end the loop.
3205 */
3206 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3207 ret = show_one_reflog_ent(&sb, fn, cb_data);
3208 strbuf_reset(&sb);
3209 break;
3210 }
3211
3212 if (bp == buf) {
3213 /*
3214 * We are at the start of the buffer, and there
3215 * is more file to read backwards. Which means
3216 * we are in the middle of a line. Note that we
3217 * may get here even if *bp was a newline; that
3218 * just means we are at the exact end of the
3219 * previous line, rather than some spot in the
3220 * middle.
3221 *
3222 * Save away what we have to be combined with
3223 * the data from the next read.
3224 */
3225 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3226 break;
3227 }
3228 }
3229
3230 }
3231 if (!ret && sb.len)
3232 die("BUG: reverse reflog parser had leftover data");
3233
3234 fclose(logfp);
3235 strbuf_release(&sb);
3236 return ret;
3237}
3238
e3688bd6
DT
3239static int files_for_each_reflog_ent(struct ref_store *ref_store,
3240 const char *refname,
3241 each_reflog_ent_fn fn, void *cb_data)
7bd9bcf3
MH
3242{
3243 FILE *logfp;
3244 struct strbuf sb = STRBUF_INIT;
3245 int ret = 0;
3246
e3688bd6
DT
3247 /* Check validity (but we don't need the result): */
3248 files_downcast(ref_store, 0, "for_each_reflog_ent");
3249
7bd9bcf3
MH
3250 logfp = fopen(git_path("logs/%s", refname), "r");
3251 if (!logfp)
3252 return -1;
3253
3254 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3255 ret = show_one_reflog_ent(&sb, fn, cb_data);
3256 fclose(logfp);
3257 strbuf_release(&sb);
3258 return ret;
3259}
7bd9bcf3 3260
2880d16f
MH
3261struct files_reflog_iterator {
3262 struct ref_iterator base;
7bd9bcf3 3263
2880d16f
MH
3264 struct dir_iterator *dir_iterator;
3265 struct object_id oid;
3266};
7bd9bcf3 3267
2880d16f
MH
3268static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
3269{
3270 struct files_reflog_iterator *iter =
3271 (struct files_reflog_iterator *)ref_iterator;
3272 struct dir_iterator *diter = iter->dir_iterator;
3273 int ok;
3274
3275 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
3276 int flags;
3277
3278 if (!S_ISREG(diter->st.st_mode))
7bd9bcf3 3279 continue;
2880d16f
MH
3280 if (diter->basename[0] == '.')
3281 continue;
3282 if (ends_with(diter->basename, ".lock"))
7bd9bcf3 3283 continue;
7bd9bcf3 3284
2880d16f
MH
3285 if (read_ref_full(diter->relative_path, 0,
3286 iter->oid.hash, &flags)) {
3287 error("bad ref for %s", diter->path.buf);
3288 continue;
7bd9bcf3 3289 }
2880d16f
MH
3290
3291 iter->base.refname = diter->relative_path;
3292 iter->base.oid = &iter->oid;
3293 iter->base.flags = flags;
3294 return ITER_OK;
7bd9bcf3 3295 }
2880d16f
MH
3296
3297 iter->dir_iterator = NULL;
3298 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
3299 ok = ITER_ERROR;
3300 return ok;
3301}
3302
3303static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
3304 struct object_id *peeled)
3305{
3306 die("BUG: ref_iterator_peel() called for reflog_iterator");
3307}
3308
3309static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
3310{
3311 struct files_reflog_iterator *iter =
3312 (struct files_reflog_iterator *)ref_iterator;
3313 int ok = ITER_DONE;
3314
3315 if (iter->dir_iterator)
3316 ok = dir_iterator_abort(iter->dir_iterator);
3317
3318 base_ref_iterator_free(ref_iterator);
3319 return ok;
3320}
3321
3322static struct ref_iterator_vtable files_reflog_iterator_vtable = {
3323 files_reflog_iterator_advance,
3324 files_reflog_iterator_peel,
3325 files_reflog_iterator_abort
3326};
3327
e3688bd6 3328static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2880d16f
MH
3329{
3330 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
3331 struct ref_iterator *ref_iterator = &iter->base;
3332
e3688bd6
DT
3333 /* Check validity (but we don't need the result): */
3334 files_downcast(ref_store, 0, "reflog_iterator_begin");
3335
2880d16f
MH
3336 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
3337 iter->dir_iterator = dir_iterator_begin(git_path("logs"));
3338 return ref_iterator;
7bd9bcf3
MH
3339}
3340
7bd9bcf3
MH
3341static int ref_update_reject_duplicates(struct string_list *refnames,
3342 struct strbuf *err)
3343{
3344 int i, n = refnames->nr;
3345
3346 assert(err);
3347
3348 for (i = 1; i < n; i++)
3349 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3350 strbuf_addf(err,
0568c8e9 3351 "multiple updates for ref '%s' not allowed.",
7bd9bcf3
MH
3352 refnames->items[i].string);
3353 return 1;
3354 }
3355 return 0;
3356}
3357
165056b2 3358/*
92b1551b
MH
3359 * If update is a direct update of head_ref (the reference pointed to
3360 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
3361 */
3362static int split_head_update(struct ref_update *update,
3363 struct ref_transaction *transaction,
3364 const char *head_ref,
3365 struct string_list *affected_refnames,
3366 struct strbuf *err)
3367{
3368 struct string_list_item *item;
3369 struct ref_update *new_update;
3370
3371 if ((update->flags & REF_LOG_ONLY) ||
3372 (update->flags & REF_ISPRUNING) ||
3373 (update->flags & REF_UPDATE_VIA_HEAD))
3374 return 0;
3375
3376 if (strcmp(update->refname, head_ref))
3377 return 0;
3378
3379 /*
3380 * First make sure that HEAD is not already in the
3381 * transaction. This insertion is O(N) in the transaction
3382 * size, but it happens at most once per transaction.
3383 */
3384 item = string_list_insert(affected_refnames, "HEAD");
3385 if (item->util) {
3386 /* An entry already existed */
3387 strbuf_addf(err,
3388 "multiple updates for 'HEAD' (including one "
3389 "via its referent '%s') are not allowed",
3390 update->refname);
3391 return TRANSACTION_NAME_CONFLICT;
3392 }
3393
3394 new_update = ref_transaction_add_update(
3395 transaction, "HEAD",
3396 update->flags | REF_LOG_ONLY | REF_NODEREF,
3397 update->new_sha1, update->old_sha1,
3398 update->msg);
3399
3400 item->util = new_update;
3401
3402 return 0;
3403}
3404
3405/*
3406 * update is for a symref that points at referent and doesn't have
3407 * REF_NODEREF set. Split it into two updates:
3408 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
3409 * - A new, separate update for the referent reference
3410 * Note that the new update will itself be subject to splitting when
3411 * the iteration gets to it.
3412 */
fcc42ea0
MH
3413static int split_symref_update(struct files_ref_store *refs,
3414 struct ref_update *update,
92b1551b
MH
3415 const char *referent,
3416 struct ref_transaction *transaction,
3417 struct string_list *affected_refnames,
3418 struct strbuf *err)
3419{
3420 struct string_list_item *item;
3421 struct ref_update *new_update;
3422 unsigned int new_flags;
3423
3424 /*
3425 * First make sure that referent is not already in the
3426 * transaction. This insertion is O(N) in the transaction
3427 * size, but it happens at most once per symref in a
3428 * transaction.
3429 */
3430 item = string_list_insert(affected_refnames, referent);
3431 if (item->util) {
3432 /* An entry already existed */
3433 strbuf_addf(err,
3434 "multiple updates for '%s' (including one "
3435 "via symref '%s') are not allowed",
3436 referent, update->refname);
3437 return TRANSACTION_NAME_CONFLICT;
3438 }
3439
3440 new_flags = update->flags;
3441 if (!strcmp(update->refname, "HEAD")) {
3442 /*
3443 * Record that the new update came via HEAD, so that
3444 * when we process it, split_head_update() doesn't try
3445 * to add another reflog update for HEAD. Note that
3446 * this bit will be propagated if the new_update
3447 * itself needs to be split.
3448 */
3449 new_flags |= REF_UPDATE_VIA_HEAD;
3450 }
3451
3452 new_update = ref_transaction_add_update(
3453 transaction, referent, new_flags,
3454 update->new_sha1, update->old_sha1,
3455 update->msg);
3456
6e30b2f6
MH
3457 new_update->parent_update = update;
3458
3459 /*
3460 * Change the symbolic ref update to log only. Also, it
3461 * doesn't need to check its old SHA-1 value, as that will be
3462 * done when new_update is processed.
3463 */
92b1551b 3464 update->flags |= REF_LOG_ONLY | REF_NODEREF;
6e30b2f6 3465 update->flags &= ~REF_HAVE_OLD;
92b1551b
MH
3466
3467 item->util = new_update;
3468
3469 return 0;
3470}
3471
6e30b2f6
MH
3472/*
3473 * Return the refname under which update was originally requested.
3474 */
3475static const char *original_update_refname(struct ref_update *update)
3476{
3477 while (update->parent_update)
3478 update = update->parent_update;
3479
3480 return update->refname;
3481}
3482
92b1551b
MH
3483/*
3484 * Prepare for carrying out update:
3485 * - Lock the reference referred to by update.
3486 * - Read the reference under lock.
3487 * - Check that its old SHA-1 value (if specified) is correct, and in
3488 * any case record it in update->lock->old_oid for later use when
3489 * writing the reflog.
3490 * - If it is a symref update without REF_NODEREF, split it up into a
3491 * REF_LOG_ONLY update of the symref and add a separate update for
3492 * the referent to transaction.
3493 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
3494 * update of HEAD.
165056b2 3495 */
b3bbbc5c
MH
3496static int lock_ref_for_update(struct files_ref_store *refs,
3497 struct ref_update *update,
165056b2 3498 struct ref_transaction *transaction,
92b1551b 3499 const char *head_ref,
165056b2
MH
3500 struct string_list *affected_refnames,
3501 struct strbuf *err)
3502{
92b1551b
MH
3503 struct strbuf referent = STRBUF_INIT;
3504 int mustexist = (update->flags & REF_HAVE_OLD) &&
3505 !is_null_sha1(update->old_sha1);
165056b2 3506 int ret;
92b1551b 3507 struct ref_lock *lock;
165056b2 3508
b3bbbc5c
MH
3509 assert_main_repository(&refs->base, "lock_ref_for_update");
3510
92b1551b 3511 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
165056b2 3512 update->flags |= REF_DELETING;
92b1551b
MH
3513
3514 if (head_ref) {
3515 ret = split_head_update(update, transaction, head_ref,
3516 affected_refnames, err);
3517 if (ret)
3518 return ret;
3519 }
3520
f7b0a987 3521 ret = lock_raw_ref(refs, update->refname, mustexist,
92b1551b
MH
3522 affected_refnames, NULL,
3523 &update->lock, &referent,
3524 &update->type, err);
3525
3526 if (ret) {
165056b2
MH
3527 char *reason;
3528
165056b2
MH
3529 reason = strbuf_detach(err, NULL);
3530 strbuf_addf(err, "cannot lock ref '%s': %s",
3531 update->refname, reason);
3532 free(reason);
3533 return ret;
3534 }
92b1551b
MH
3535
3536 lock = update->lock;
3537
8169d0d0 3538 if (update->type & REF_ISSYMREF) {
6e30b2f6
MH
3539 if (update->flags & REF_NODEREF) {
3540 /*
3541 * We won't be reading the referent as part of
3542 * the transaction, so we have to read it here
3543 * to record and possibly check old_sha1:
3544 */
3545 if (read_ref_full(update->refname,
3546 mustexist ? RESOLVE_REF_READING : 0,
3547 lock->old_oid.hash, NULL)) {
3548 if (update->flags & REF_HAVE_OLD) {
3549 strbuf_addf(err, "cannot lock ref '%s': "
3550 "can't resolve old value",
3551 update->refname);
3552 return TRANSACTION_GENERIC_ERROR;
3553 } else {
3554 hashclr(lock->old_oid.hash);
3555 }
3556 }
3557 if ((update->flags & REF_HAVE_OLD) &&
3558 hashcmp(lock->old_oid.hash, update->old_sha1)) {
3559 strbuf_addf(err, "cannot lock ref '%s': "
3560 "is at %s but expected %s",
3561 update->refname,
3562 sha1_to_hex(lock->old_oid.hash),
3563 sha1_to_hex(update->old_sha1));
8169d0d0 3564 return TRANSACTION_GENERIC_ERROR;
8169d0d0 3565 }
92b1551b 3566
6e30b2f6
MH
3567 } else {
3568 /*
3569 * Create a new update for the reference this
3570 * symref is pointing at. Also, we will record
3571 * and verify old_sha1 for this update as part
3572 * of processing the split-off update, so we
3573 * don't have to do it here.
3574 */
fcc42ea0
MH
3575 ret = split_symref_update(refs, update,
3576 referent.buf, transaction,
92b1551b
MH
3577 affected_refnames, err);
3578 if (ret)
3579 return ret;
3580 }
6e30b2f6
MH
3581 } else {
3582 struct ref_update *parent_update;
8169d0d0 3583
6e30b2f6
MH
3584 /*
3585 * If this update is happening indirectly because of a
3586 * symref update, record the old SHA-1 in the parent
3587 * update:
3588 */
3589 for (parent_update = update->parent_update;
3590 parent_update;
3591 parent_update = parent_update->parent_update) {
3592 oidcpy(&parent_update->lock->old_oid, &lock->old_oid);
3593 }
3594
3595 if ((update->flags & REF_HAVE_OLD) &&
3596 hashcmp(lock->old_oid.hash, update->old_sha1)) {
3597 if (is_null_sha1(update->old_sha1))
3598 strbuf_addf(err, "cannot lock ref '%s': reference already exists",
3599 original_update_refname(update));
3600 else
3601 strbuf_addf(err, "cannot lock ref '%s': is at %s but expected %s",
3602 original_update_refname(update),
3603 sha1_to_hex(lock->old_oid.hash),
3604 sha1_to_hex(update->old_sha1));
3605
3606 return TRANSACTION_GENERIC_ERROR;
3607 }
92b1551b
MH
3608 }
3609
165056b2
MH
3610 if ((update->flags & REF_HAVE_NEW) &&
3611 !(update->flags & REF_DELETING) &&
3612 !(update->flags & REF_LOG_ONLY)) {
92b1551b
MH
3613 if (!(update->type & REF_ISSYMREF) &&
3614 !hashcmp(lock->old_oid.hash, update->new_sha1)) {
165056b2
MH
3615 /*
3616 * The reference already has the desired
3617 * value, so we don't need to write it.
3618 */
92b1551b 3619 } else if (write_ref_to_lockfile(lock, update->new_sha1,
165056b2
MH
3620 err)) {
3621 char *write_err = strbuf_detach(err, NULL);
3622
3623 /*
3624 * The lock was freed upon failure of
3625 * write_ref_to_lockfile():
3626 */
3627 update->lock = NULL;
3628 strbuf_addf(err,
3629 "cannot update the ref '%s': %s",
3630 update->refname, write_err);
3631 free(write_err);
3632 return TRANSACTION_GENERIC_ERROR;
3633 } else {
3634 update->flags |= REF_NEEDS_COMMIT;
3635 }
3636 }
3637 if (!(update->flags & REF_NEEDS_COMMIT)) {
3638 /*
3639 * We didn't call write_ref_to_lockfile(), so
3640 * the lockfile is still open. Close it to
3641 * free up the file descriptor:
3642 */
92b1551b 3643 if (close_ref(lock)) {
165056b2
MH
3644 strbuf_addf(err, "couldn't close '%s.lock'",
3645 update->refname);
3646 return TRANSACTION_GENERIC_ERROR;
3647 }
3648 }
3649 return 0;
3650}
3651
127b42a1
RS
3652static int files_transaction_commit(struct ref_store *ref_store,
3653 struct ref_transaction *transaction,
3654 struct strbuf *err)
7bd9bcf3 3655{
00eebe35 3656 struct files_ref_store *refs =
127b42a1 3657 files_downcast(ref_store, 0, "ref_transaction_commit");
7bd9bcf3 3658 int ret = 0, i;
7bd9bcf3
MH
3659 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3660 struct string_list_item *ref_to_delete;
3661 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
92b1551b
MH
3662 char *head_ref = NULL;
3663 int head_type;
3664 struct object_id head_oid;
7bd9bcf3
MH
3665
3666 assert(err);
3667
3668 if (transaction->state != REF_TRANSACTION_OPEN)
3669 die("BUG: commit called for transaction that is not open");
3670
efe47281 3671 if (!transaction->nr) {
7bd9bcf3
MH
3672 transaction->state = REF_TRANSACTION_CLOSED;
3673 return 0;
3674 }
3675
92b1551b
MH
3676 /*
3677 * Fail if a refname appears more than once in the
3678 * transaction. (If we end up splitting up any updates using
3679 * split_symref_update() or split_head_update(), those
3680 * functions will check that the new updates don't have the
3681 * same refname as any existing ones.)
3682 */
3683 for (i = 0; i < transaction->nr; i++) {
3684 struct ref_update *update = transaction->updates[i];
3685 struct string_list_item *item =
3686 string_list_append(&affected_refnames, update->refname);
3687
3688 /*
3689 * We store a pointer to update in item->util, but at
3690 * the moment we never use the value of this field
3691 * except to check whether it is non-NULL.
3692 */
3693 item->util = update;
3694 }
7bd9bcf3
MH
3695 string_list_sort(&affected_refnames);
3696 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3697 ret = TRANSACTION_GENERIC_ERROR;
3698 goto cleanup;
3699 }
3700
92b1551b
MH
3701 /*
3702 * Special hack: If a branch is updated directly and HEAD
3703 * points to it (may happen on the remote side of a push
3704 * for example) then logically the HEAD reflog should be
3705 * updated too.
3706 *
3707 * A generic solution would require reverse symref lookups,
3708 * but finding all symrefs pointing to a given branch would be
3709 * rather costly for this rare event (the direct update of a
3710 * branch) to be worth it. So let's cheat and check with HEAD
3711 * only, which should cover 99% of all usage scenarios (even
3712 * 100% of the default ones).
3713 *
3714 * So if HEAD is a symbolic reference, then record the name of
3715 * the reference that it points to. If we see an update of
3716 * head_ref within the transaction, then split_head_update()
3717 * arranges for the reflog of HEAD to be updated, too.
3718 */
3719 head_ref = resolve_refdup("HEAD", RESOLVE_REF_NO_RECURSE,
3720 head_oid.hash, &head_type);
3721
3722 if (head_ref && !(head_type & REF_ISSYMREF)) {
3723 free(head_ref);
3724 head_ref = NULL;
3725 }
3726
7bd9bcf3
MH
3727 /*
3728 * Acquire all locks, verify old values if provided, check
3729 * that new values are valid, and write new values to the
3730 * lockfiles, ready to be activated. Only keep one lockfile
3731 * open at a time to avoid running out of file descriptors.
3732 */
efe47281
MH
3733 for (i = 0; i < transaction->nr; i++) {
3734 struct ref_update *update = transaction->updates[i];
7bd9bcf3 3735
b3bbbc5c
MH
3736 ret = lock_ref_for_update(refs, update, transaction,
3737 head_ref, &affected_refnames, err);
165056b2 3738 if (ret)
7bd9bcf3 3739 goto cleanup;
7bd9bcf3
MH
3740 }
3741
3742 /* Perform updates first so live commits remain referenced */
efe47281
MH
3743 for (i = 0; i < transaction->nr; i++) {
3744 struct ref_update *update = transaction->updates[i];
92b1551b 3745 struct ref_lock *lock = update->lock;
7bd9bcf3 3746
d99aa884
DT
3747 if (update->flags & REF_NEEDS_COMMIT ||
3748 update->flags & REF_LOG_ONLY) {
92b1551b
MH
3749 if (log_ref_write(lock->ref_name, lock->old_oid.hash,
3750 update->new_sha1,
3751 update->msg, update->flags, err)) {
3752 char *old_msg = strbuf_detach(err, NULL);
3753
3754 strbuf_addf(err, "cannot update the ref '%s': %s",
3755 lock->ref_name, old_msg);
3756 free(old_msg);
3757 unlock_ref(lock);
7bd9bcf3
MH
3758 update->lock = NULL;
3759 ret = TRANSACTION_GENERIC_ERROR;
3760 goto cleanup;
92b1551b
MH
3761 }
3762 }
3763 if (update->flags & REF_NEEDS_COMMIT) {
00eebe35 3764 clear_loose_ref_cache(refs);
92b1551b
MH
3765 if (commit_ref(lock)) {
3766 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
3767 unlock_ref(lock);
7bd9bcf3 3768 update->lock = NULL;
92b1551b
MH
3769 ret = TRANSACTION_GENERIC_ERROR;
3770 goto cleanup;
7bd9bcf3
MH
3771 }
3772 }
3773 }
7bd9bcf3 3774 /* Perform deletes now that updates are safely completed */
efe47281
MH
3775 for (i = 0; i < transaction->nr; i++) {
3776 struct ref_update *update = transaction->updates[i];
7bd9bcf3 3777
d99aa884
DT
3778 if (update->flags & REF_DELETING &&
3779 !(update->flags & REF_LOG_ONLY)) {
7bd9bcf3
MH
3780 if (delete_ref_loose(update->lock, update->type, err)) {
3781 ret = TRANSACTION_GENERIC_ERROR;
3782 goto cleanup;
3783 }
3784
3785 if (!(update->flags & REF_ISPRUNING))
3786 string_list_append(&refs_to_delete,
3787 update->lock->ref_name);
3788 }
3789 }
3790
0a95ac5f 3791 if (repack_without_refs(refs, &refs_to_delete, err)) {
7bd9bcf3
MH
3792 ret = TRANSACTION_GENERIC_ERROR;
3793 goto cleanup;
3794 }
3795 for_each_string_list_item(ref_to_delete, &refs_to_delete)
3796 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
00eebe35 3797 clear_loose_ref_cache(refs);
7bd9bcf3
MH
3798
3799cleanup:
3800 transaction->state = REF_TRANSACTION_CLOSED;
3801
efe47281
MH
3802 for (i = 0; i < transaction->nr; i++)
3803 if (transaction->updates[i]->lock)
3804 unlock_ref(transaction->updates[i]->lock);
7bd9bcf3 3805 string_list_clear(&refs_to_delete, 0);
92b1551b 3806 free(head_ref);
7bd9bcf3 3807 string_list_clear(&affected_refnames, 0);
92b1551b 3808
7bd9bcf3
MH
3809 return ret;
3810}
3811
3812static int ref_present(const char *refname,
3813 const struct object_id *oid, int flags, void *cb_data)
3814{
3815 struct string_list *affected_refnames = cb_data;
3816
3817 return string_list_has_string(affected_refnames, refname);
3818}
3819
fc681463
DT
3820static int files_initial_transaction_commit(struct ref_store *ref_store,
3821 struct ref_transaction *transaction,
3822 struct strbuf *err)
7bd9bcf3 3823{
d99825ab 3824 struct files_ref_store *refs =
fc681463 3825 files_downcast(ref_store, 0, "initial_ref_transaction_commit");
7bd9bcf3 3826 int ret = 0, i;
7bd9bcf3
MH
3827 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;