refs: move submodule code out of files-backend.c
[git/git.git] / refs / files-backend.c
CommitLineData
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1#include "../cache.h"
2#include "../refs.h"
3#include "refs-internal.h"
3bc581b9 4#include "../iterator.h"
2880d16f 5#include "../dir-iterator.h"
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6#include "../lockfile.h"
7#include "../object.h"
8#include "../dir.h"
9
10struct ref_lock {
11 char *ref_name;
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12 struct lock_file *lk;
13 struct object_id old_oid;
14};
15
16struct ref_entry;
17
18/*
19 * Information used (along with the information in ref_entry) to
20 * describe a single cached reference. This data structure only
21 * occurs embedded in a union in struct ref_entry, and only when
22 * (ref_entry->flag & REF_DIR) is zero.
23 */
24struct ref_value {
25 /*
26 * The name of the object to which this reference resolves
27 * (which may be a tag object). If REF_ISBROKEN, this is
28 * null. If REF_ISSYMREF, then this is the name of the object
29 * referred to by the last reference in the symlink chain.
30 */
31 struct object_id oid;
32
33 /*
34 * If REF_KNOWS_PEELED, then this field holds the peeled value
35 * of this reference, or null if the reference is known not to
36 * be peelable. See the documentation for peel_ref() for an
37 * exact definition of "peelable".
38 */
39 struct object_id peeled;
40};
41
65a0a8e5 42struct files_ref_store;
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43
44/*
45 * Information used (along with the information in ref_entry) to
46 * describe a level in the hierarchy of references. This data
47 * structure only occurs embedded in a union in struct ref_entry, and
48 * only when (ref_entry.flag & REF_DIR) is set. In that case,
49 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
50 * in the directory have already been read:
51 *
52 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
53 * or packed references, already read.
54 *
55 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
56 * references that hasn't been read yet (nor has any of its
57 * subdirectories).
58 *
59 * Entries within a directory are stored within a growable array of
60 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
61 * sorted are sorted by their component name in strcmp() order and the
62 * remaining entries are unsorted.
63 *
64 * Loose references are read lazily, one directory at a time. When a
65 * directory of loose references is read, then all of the references
66 * in that directory are stored, and REF_INCOMPLETE stubs are created
67 * for any subdirectories, but the subdirectories themselves are not
68 * read. The reading is triggered by get_ref_dir().
69 */
70struct ref_dir {
71 int nr, alloc;
72
73 /*
74 * Entries with index 0 <= i < sorted are sorted by name. New
75 * entries are appended to the list unsorted, and are sorted
76 * only when required; thus we avoid the need to sort the list
77 * after the addition of every reference.
78 */
79 int sorted;
80
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81 /* A pointer to the files_ref_store that contains this ref_dir. */
82 struct files_ref_store *ref_store;
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83
84 struct ref_entry **entries;
85};
86
87/*
88 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
89 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
90 * public values; see refs.h.
91 */
92
93/*
94 * The field ref_entry->u.value.peeled of this value entry contains
95 * the correct peeled value for the reference, which might be
96 * null_sha1 if the reference is not a tag or if it is broken.
97 */
98#define REF_KNOWS_PEELED 0x10
99
100/* ref_entry represents a directory of references */
101#define REF_DIR 0x20
102
103/*
104 * Entry has not yet been read from disk (used only for REF_DIR
105 * entries representing loose references)
106 */
107#define REF_INCOMPLETE 0x40
108
109/*
110 * A ref_entry represents either a reference or a "subdirectory" of
111 * references.
112 *
113 * Each directory in the reference namespace is represented by a
114 * ref_entry with (flags & REF_DIR) set and containing a subdir member
115 * that holds the entries in that directory that have been read so
116 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
117 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
118 * used for loose reference directories.
119 *
120 * References are represented by a ref_entry with (flags & REF_DIR)
121 * unset and a value member that describes the reference's value. The
122 * flag member is at the ref_entry level, but it is also needed to
123 * interpret the contents of the value field (in other words, a
124 * ref_value object is not very much use without the enclosing
125 * ref_entry).
126 *
127 * Reference names cannot end with slash and directories' names are
128 * always stored with a trailing slash (except for the top-level
129 * directory, which is always denoted by ""). This has two nice
130 * consequences: (1) when the entries in each subdir are sorted
131 * lexicographically by name (as they usually are), the references in
132 * a whole tree can be generated in lexicographic order by traversing
133 * the tree in left-to-right, depth-first order; (2) the names of
134 * references and subdirectories cannot conflict, and therefore the
135 * presence of an empty subdirectory does not block the creation of a
136 * similarly-named reference. (The fact that reference names with the
137 * same leading components can conflict *with each other* is a
138 * separate issue that is regulated by verify_refname_available().)
139 *
140 * Please note that the name field contains the fully-qualified
141 * reference (or subdirectory) name. Space could be saved by only
142 * storing the relative names. But that would require the full names
143 * to be generated on the fly when iterating in do_for_each_ref(), and
144 * would break callback functions, who have always been able to assume
145 * that the name strings that they are passed will not be freed during
146 * the iteration.
147 */
148struct ref_entry {
149 unsigned char flag; /* ISSYMREF? ISPACKED? */
150 union {
151 struct ref_value value; /* if not (flags&REF_DIR) */
152 struct ref_dir subdir; /* if (flags&REF_DIR) */
153 } u;
154 /*
155 * The full name of the reference (e.g., "refs/heads/master")
156 * or the full name of the directory with a trailing slash
157 * (e.g., "refs/heads/"):
158 */
159 char name[FLEX_ARRAY];
160};
161
162static void read_loose_refs(const char *dirname, struct ref_dir *dir);
163static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len);
65a0a8e5 164static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
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165 const char *dirname, size_t len,
166 int incomplete);
167static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
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168static int files_log_ref_write(struct files_ref_store *refs,
169 const char *refname, const unsigned char *old_sha1,
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170 const unsigned char *new_sha1, const char *msg,
171 int flags, struct strbuf *err);
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172
173static struct ref_dir *get_ref_dir(struct ref_entry *entry)
174{
175 struct ref_dir *dir;
176 assert(entry->flag & REF_DIR);
177 dir = &entry->u.subdir;
178 if (entry->flag & REF_INCOMPLETE) {
179 read_loose_refs(entry->name, dir);
180
181 /*
182 * Manually add refs/bisect, which, being
183 * per-worktree, might not appear in the directory
184 * listing for refs/ in the main repo.
185 */
186 if (!strcmp(entry->name, "refs/")) {
187 int pos = search_ref_dir(dir, "refs/bisect/", 12);
188 if (pos < 0) {
189 struct ref_entry *child_entry;
65a0a8e5 190 child_entry = create_dir_entry(dir->ref_store,
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191 "refs/bisect/",
192 12, 1);
193 add_entry_to_dir(dir, child_entry);
194 read_loose_refs("refs/bisect",
195 &child_entry->u.subdir);
196 }
197 }
198 entry->flag &= ~REF_INCOMPLETE;
199 }
200 return dir;
201}
202
203static struct ref_entry *create_ref_entry(const char *refname,
204 const unsigned char *sha1, int flag,
205 int check_name)
206{
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207 struct ref_entry *ref;
208
209 if (check_name &&
210 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
211 die("Reference has invalid format: '%s'", refname);
96ffc06f 212 FLEX_ALLOC_STR(ref, name, refname);
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213 hashcpy(ref->u.value.oid.hash, sha1);
214 oidclr(&ref->u.value.peeled);
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215 ref->flag = flag;
216 return ref;
217}
218
219static void clear_ref_dir(struct ref_dir *dir);
220
221static void free_ref_entry(struct ref_entry *entry)
222{
223 if (entry->flag & REF_DIR) {
224 /*
225 * Do not use get_ref_dir() here, as that might
226 * trigger the reading of loose refs.
227 */
228 clear_ref_dir(&entry->u.subdir);
229 }
230 free(entry);
231}
232
233/*
234 * Add a ref_entry to the end of dir (unsorted). Entry is always
235 * stored directly in dir; no recursion into subdirectories is
236 * done.
237 */
238static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
239{
240 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
241 dir->entries[dir->nr++] = entry;
242 /* optimize for the case that entries are added in order */
243 if (dir->nr == 1 ||
244 (dir->nr == dir->sorted + 1 &&
245 strcmp(dir->entries[dir->nr - 2]->name,
246 dir->entries[dir->nr - 1]->name) < 0))
247 dir->sorted = dir->nr;
248}
249
250/*
251 * Clear and free all entries in dir, recursively.
252 */
253static void clear_ref_dir(struct ref_dir *dir)
254{
255 int i;
256 for (i = 0; i < dir->nr; i++)
257 free_ref_entry(dir->entries[i]);
258 free(dir->entries);
259 dir->sorted = dir->nr = dir->alloc = 0;
260 dir->entries = NULL;
261}
262
263/*
264 * Create a struct ref_entry object for the specified dirname.
265 * dirname is the name of the directory with a trailing slash (e.g.,
266 * "refs/heads/") or "" for the top-level directory.
267 */
65a0a8e5 268static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
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269 const char *dirname, size_t len,
270 int incomplete)
271{
272 struct ref_entry *direntry;
96ffc06f 273 FLEX_ALLOC_MEM(direntry, name, dirname, len);
65a0a8e5 274 direntry->u.subdir.ref_store = ref_store;
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275 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
276 return direntry;
277}
278
279static int ref_entry_cmp(const void *a, const void *b)
280{
281 struct ref_entry *one = *(struct ref_entry **)a;
282 struct ref_entry *two = *(struct ref_entry **)b;
283 return strcmp(one->name, two->name);
284}
285
286static void sort_ref_dir(struct ref_dir *dir);
287
288struct string_slice {
289 size_t len;
290 const char *str;
291};
292
293static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
294{
295 const struct string_slice *key = key_;
296 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
297 int cmp = strncmp(key->str, ent->name, key->len);
298 if (cmp)
299 return cmp;
300 return '\0' - (unsigned char)ent->name[key->len];
301}
302
303/*
304 * Return the index of the entry with the given refname from the
305 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
306 * no such entry is found. dir must already be complete.
307 */
308static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
309{
310 struct ref_entry **r;
311 struct string_slice key;
312
313 if (refname == NULL || !dir->nr)
314 return -1;
315
316 sort_ref_dir(dir);
317 key.len = len;
318 key.str = refname;
319 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
320 ref_entry_cmp_sslice);
321
322 if (r == NULL)
323 return -1;
324
325 return r - dir->entries;
326}
327
328/*
329 * Search for a directory entry directly within dir (without
330 * recursing). Sort dir if necessary. subdirname must be a directory
331 * name (i.e., end in '/'). If mkdir is set, then create the
332 * directory if it is missing; otherwise, return NULL if the desired
333 * directory cannot be found. dir must already be complete.
334 */
335static struct ref_dir *search_for_subdir(struct ref_dir *dir,
336 const char *subdirname, size_t len,
337 int mkdir)
338{
339 int entry_index = search_ref_dir(dir, subdirname, len);
340 struct ref_entry *entry;
341 if (entry_index == -1) {
342 if (!mkdir)
343 return NULL;
344 /*
345 * Since dir is complete, the absence of a subdir
346 * means that the subdir really doesn't exist;
347 * therefore, create an empty record for it but mark
348 * the record complete.
349 */
65a0a8e5 350 entry = create_dir_entry(dir->ref_store, subdirname, len, 0);
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351 add_entry_to_dir(dir, entry);
352 } else {
353 entry = dir->entries[entry_index];
354 }
355 return get_ref_dir(entry);
356}
357
358/*
359 * If refname is a reference name, find the ref_dir within the dir
360 * tree that should hold refname. If refname is a directory name
361 * (i.e., ends in '/'), then return that ref_dir itself. dir must
362 * represent the top-level directory and must already be complete.
363 * Sort ref_dirs and recurse into subdirectories as necessary. If
364 * mkdir is set, then create any missing directories; otherwise,
365 * return NULL if the desired directory cannot be found.
366 */
367static struct ref_dir *find_containing_dir(struct ref_dir *dir,
368 const char *refname, int mkdir)
369{
370 const char *slash;
371 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
372 size_t dirnamelen = slash - refname + 1;
373 struct ref_dir *subdir;
374 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
375 if (!subdir) {
376 dir = NULL;
377 break;
378 }
379 dir = subdir;
380 }
381
382 return dir;
383}
384
385/*
386 * Find the value entry with the given name in dir, sorting ref_dirs
387 * and recursing into subdirectories as necessary. If the name is not
388 * found or it corresponds to a directory entry, return NULL.
389 */
390static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
391{
392 int entry_index;
393 struct ref_entry *entry;
394 dir = find_containing_dir(dir, refname, 0);
395 if (!dir)
396 return NULL;
397 entry_index = search_ref_dir(dir, refname, strlen(refname));
398 if (entry_index == -1)
399 return NULL;
400 entry = dir->entries[entry_index];
401 return (entry->flag & REF_DIR) ? NULL : entry;
402}
403
404/*
405 * Remove the entry with the given name from dir, recursing into
406 * subdirectories as necessary. If refname is the name of a directory
407 * (i.e., ends with '/'), then remove the directory and its contents.
408 * If the removal was successful, return the number of entries
409 * remaining in the directory entry that contained the deleted entry.
410 * If the name was not found, return -1. Please note that this
411 * function only deletes the entry from the cache; it does not delete
412 * it from the filesystem or ensure that other cache entries (which
413 * might be symbolic references to the removed entry) are updated.
414 * Nor does it remove any containing dir entries that might be made
415 * empty by the removal. dir must represent the top-level directory
416 * and must already be complete.
417 */
418static int remove_entry(struct ref_dir *dir, const char *refname)
419{
420 int refname_len = strlen(refname);
421 int entry_index;
422 struct ref_entry *entry;
423 int is_dir = refname[refname_len - 1] == '/';
424 if (is_dir) {
425 /*
426 * refname represents a reference directory. Remove
427 * the trailing slash; otherwise we will get the
428 * directory *representing* refname rather than the
429 * one *containing* it.
430 */
431 char *dirname = xmemdupz(refname, refname_len - 1);
432 dir = find_containing_dir(dir, dirname, 0);
433 free(dirname);
434 } else {
435 dir = find_containing_dir(dir, refname, 0);
436 }
437 if (!dir)
438 return -1;
439 entry_index = search_ref_dir(dir, refname, refname_len);
440 if (entry_index == -1)
441 return -1;
442 entry = dir->entries[entry_index];
443
444 memmove(&dir->entries[entry_index],
445 &dir->entries[entry_index + 1],
446 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
447 );
448 dir->nr--;
449 if (dir->sorted > entry_index)
450 dir->sorted--;
451 free_ref_entry(entry);
452 return dir->nr;
453}
454
455/*
456 * Add a ref_entry to the ref_dir (unsorted), recursing into
457 * subdirectories as necessary. dir must represent the top-level
458 * directory. Return 0 on success.
459 */
460static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
461{
462 dir = find_containing_dir(dir, ref->name, 1);
463 if (!dir)
464 return -1;
465 add_entry_to_dir(dir, ref);
466 return 0;
467}
468
469/*
470 * Emit a warning and return true iff ref1 and ref2 have the same name
471 * and the same sha1. Die if they have the same name but different
472 * sha1s.
473 */
474static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
475{
476 if (strcmp(ref1->name, ref2->name))
477 return 0;
478
479 /* Duplicate name; make sure that they don't conflict: */
480
481 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
482 /* This is impossible by construction */
483 die("Reference directory conflict: %s", ref1->name);
484
485 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
486 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
487
488 warning("Duplicated ref: %s", ref1->name);
489 return 1;
490}
491
492/*
493 * Sort the entries in dir non-recursively (if they are not already
494 * sorted) and remove any duplicate entries.
495 */
496static void sort_ref_dir(struct ref_dir *dir)
497{
498 int i, j;
499 struct ref_entry *last = NULL;
500
501 /*
502 * This check also prevents passing a zero-length array to qsort(),
503 * which is a problem on some platforms.
504 */
505 if (dir->sorted == dir->nr)
506 return;
507
9ed0d8d6 508 QSORT(dir->entries, dir->nr, ref_entry_cmp);
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509
510 /* Remove any duplicates: */
511 for (i = 0, j = 0; j < dir->nr; j++) {
512 struct ref_entry *entry = dir->entries[j];
513 if (last && is_dup_ref(last, entry))
514 free_ref_entry(entry);
515 else
516 last = dir->entries[i++] = entry;
517 }
518 dir->sorted = dir->nr = i;
519}
520
7bd9bcf3 521/*
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MH
522 * Return true if refname, which has the specified oid and flags, can
523 * be resolved to an object in the database. If the referred-to object
524 * does not exist, emit a warning and return false.
7bd9bcf3 525 */
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MH
526static int ref_resolves_to_object(const char *refname,
527 const struct object_id *oid,
528 unsigned int flags)
7bd9bcf3 529{
a8739244 530 if (flags & REF_ISBROKEN)
7bd9bcf3 531 return 0;
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MH
532 if (!has_sha1_file(oid->hash)) {
533 error("%s does not point to a valid object!", refname);
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534 return 0;
535 }
536 return 1;
537}
538
539/*
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540 * Return true if the reference described by entry can be resolved to
541 * an object in the database; otherwise, emit a warning and return
542 * false.
7bd9bcf3 543 */
a8739244 544static int entry_resolves_to_object(struct ref_entry *entry)
7bd9bcf3 545{
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MH
546 return ref_resolves_to_object(entry->name,
547 &entry->u.value.oid, entry->flag);
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548}
549
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550typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
551
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552/*
553 * Call fn for each reference in dir that has index in the range
554 * offset <= index < dir->nr. Recurse into subdirectories that are in
555 * that index range, sorting them before iterating. This function
556 * does not sort dir itself; it should be sorted beforehand. fn is
557 * called for all references, including broken ones.
558 */
559static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
560 each_ref_entry_fn fn, void *cb_data)
561{
562 int i;
563 assert(dir->sorted == dir->nr);
564 for (i = offset; i < dir->nr; i++) {
565 struct ref_entry *entry = dir->entries[i];
566 int retval;
567 if (entry->flag & REF_DIR) {
568 struct ref_dir *subdir = get_ref_dir(entry);
569 sort_ref_dir(subdir);
570 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
571 } else {
572 retval = fn(entry, cb_data);
573 }
574 if (retval)
575 return retval;
576 }
577 return 0;
578}
579
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580/*
581 * Load all of the refs from the dir into our in-memory cache. The hard work
582 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
583 * through all of the sub-directories. We do not even need to care about
584 * sorting, as traversal order does not matter to us.
585 */
586static void prime_ref_dir(struct ref_dir *dir)
587{
588 int i;
589 for (i = 0; i < dir->nr; i++) {
590 struct ref_entry *entry = dir->entries[i];
591 if (entry->flag & REF_DIR)
592 prime_ref_dir(get_ref_dir(entry));
593 }
594}
595
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596/*
597 * A level in the reference hierarchy that is currently being iterated
598 * through.
599 */
600struct cache_ref_iterator_level {
601 /*
602 * The ref_dir being iterated over at this level. The ref_dir
603 * is sorted before being stored here.
604 */
605 struct ref_dir *dir;
606
607 /*
608 * The index of the current entry within dir (which might
609 * itself be a directory). If index == -1, then the iteration
610 * hasn't yet begun. If index == dir->nr, then the iteration
611 * through this level is over.
612 */
613 int index;
614};
615
616/*
617 * Represent an iteration through a ref_dir in the memory cache. The
618 * iteration recurses through subdirectories.
619 */
620struct cache_ref_iterator {
621 struct ref_iterator base;
622
623 /*
624 * The number of levels currently on the stack. This is always
625 * at least 1, because when it becomes zero the iteration is
626 * ended and this struct is freed.
627 */
628 size_t levels_nr;
629
630 /* The number of levels that have been allocated on the stack */
631 size_t levels_alloc;
632
633 /*
634 * A stack of levels. levels[0] is the uppermost level that is
635 * being iterated over in this iteration. (This is not
636 * necessary the top level in the references hierarchy. If we
637 * are iterating through a subtree, then levels[0] will hold
638 * the ref_dir for that subtree, and subsequent levels will go
639 * on from there.)
640 */
641 struct cache_ref_iterator_level *levels;
642};
643
644static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
645{
646 struct cache_ref_iterator *iter =
647 (struct cache_ref_iterator *)ref_iterator;
648
649 while (1) {
650 struct cache_ref_iterator_level *level =
651 &iter->levels[iter->levels_nr - 1];
652 struct ref_dir *dir = level->dir;
653 struct ref_entry *entry;
654
655 if (level->index == -1)
656 sort_ref_dir(dir);
657
658 if (++level->index == level->dir->nr) {
659 /* This level is exhausted; pop up a level */
660 if (--iter->levels_nr == 0)
661 return ref_iterator_abort(ref_iterator);
662
663 continue;
664 }
665
666 entry = dir->entries[level->index];
667
668 if (entry->flag & REF_DIR) {
669 /* push down a level */
670 ALLOC_GROW(iter->levels, iter->levels_nr + 1,
671 iter->levels_alloc);
672
673 level = &iter->levels[iter->levels_nr++];
674 level->dir = get_ref_dir(entry);
675 level->index = -1;
676 } else {
677 iter->base.refname = entry->name;
678 iter->base.oid = &entry->u.value.oid;
679 iter->base.flags = entry->flag;
680 return ITER_OK;
681 }
682 }
683}
684
685static enum peel_status peel_entry(struct ref_entry *entry, int repeel);
686
687static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
688 struct object_id *peeled)
689{
690 struct cache_ref_iterator *iter =
691 (struct cache_ref_iterator *)ref_iterator;
692 struct cache_ref_iterator_level *level;
693 struct ref_entry *entry;
694
695 level = &iter->levels[iter->levels_nr - 1];
696
697 if (level->index == -1)
698 die("BUG: peel called before advance for cache iterator");
699
700 entry = level->dir->entries[level->index];
701
702 if (peel_entry(entry, 0))
703 return -1;
8694769f 704 oidcpy(peeled, &entry->u.value.peeled);
3bc581b9
MH
705 return 0;
706}
707
708static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator)
709{
710 struct cache_ref_iterator *iter =
711 (struct cache_ref_iterator *)ref_iterator;
712
713 free(iter->levels);
714 base_ref_iterator_free(ref_iterator);
715 return ITER_DONE;
716}
717
718static struct ref_iterator_vtable cache_ref_iterator_vtable = {
719 cache_ref_iterator_advance,
720 cache_ref_iterator_peel,
721 cache_ref_iterator_abort
722};
723
724static struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir)
725{
726 struct cache_ref_iterator *iter;
727 struct ref_iterator *ref_iterator;
728 struct cache_ref_iterator_level *level;
729
730 iter = xcalloc(1, sizeof(*iter));
731 ref_iterator = &iter->base;
732 base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable);
733 ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
734
735 iter->levels_nr = 1;
736 level = &iter->levels[0];
737 level->index = -1;
738 level->dir = dir;
739
740 return ref_iterator;
741}
742
7bd9bcf3
MH
743struct nonmatching_ref_data {
744 const struct string_list *skip;
745 const char *conflicting_refname;
746};
747
748static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
749{
750 struct nonmatching_ref_data *data = vdata;
751
752 if (data->skip && string_list_has_string(data->skip, entry->name))
753 return 0;
754
755 data->conflicting_refname = entry->name;
756 return 1;
757}
758
759/*
760 * Return 0 if a reference named refname could be created without
761 * conflicting with the name of an existing reference in dir.
762 * See verify_refname_available for more information.
763 */
764static int verify_refname_available_dir(const char *refname,
765 const struct string_list *extras,
766 const struct string_list *skip,
767 struct ref_dir *dir,
768 struct strbuf *err)
769{
770 const char *slash;
0845122c 771 const char *extra_refname;
7bd9bcf3
MH
772 int pos;
773 struct strbuf dirname = STRBUF_INIT;
774 int ret = -1;
775
776 /*
777 * For the sake of comments in this function, suppose that
778 * refname is "refs/foo/bar".
779 */
780
781 assert(err);
782
783 strbuf_grow(&dirname, strlen(refname) + 1);
784 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
785 /* Expand dirname to the new prefix, not including the trailing slash: */
786 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
787
788 /*
789 * We are still at a leading dir of the refname (e.g.,
790 * "refs/foo"; if there is a reference with that name,
791 * it is a conflict, *unless* it is in skip.
792 */
793 if (dir) {
794 pos = search_ref_dir(dir, dirname.buf, dirname.len);
795 if (pos >= 0 &&
796 (!skip || !string_list_has_string(skip, dirname.buf))) {
797 /*
798 * We found a reference whose name is
799 * a proper prefix of refname; e.g.,
800 * "refs/foo", and is not in skip.
801 */
802 strbuf_addf(err, "'%s' exists; cannot create '%s'",
803 dirname.buf, refname);
804 goto cleanup;
805 }
806 }
807
808 if (extras && string_list_has_string(extras, dirname.buf) &&
809 (!skip || !string_list_has_string(skip, dirname.buf))) {
810 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
811 refname, dirname.buf);
812 goto cleanup;
813 }
814
815 /*
816 * Otherwise, we can try to continue our search with
817 * the next component. So try to look up the
818 * directory, e.g., "refs/foo/". If we come up empty,
819 * we know there is nothing under this whole prefix,
820 * but even in that case we still have to continue the
821 * search for conflicts with extras.
822 */
823 strbuf_addch(&dirname, '/');
824 if (dir) {
825 pos = search_ref_dir(dir, dirname.buf, dirname.len);
826 if (pos < 0) {
827 /*
828 * There was no directory "refs/foo/",
829 * so there is nothing under this
830 * whole prefix. So there is no need
831 * to continue looking for conflicting
832 * references. But we need to continue
833 * looking for conflicting extras.
834 */
835 dir = NULL;
836 } else {
837 dir = get_ref_dir(dir->entries[pos]);
838 }
839 }
840 }
841
842 /*
843 * We are at the leaf of our refname (e.g., "refs/foo/bar").
844 * There is no point in searching for a reference with that
845 * name, because a refname isn't considered to conflict with
846 * itself. But we still need to check for references whose
847 * names are in the "refs/foo/bar/" namespace, because they
848 * *do* conflict.
849 */
850 strbuf_addstr(&dirname, refname + dirname.len);
851 strbuf_addch(&dirname, '/');
852
853 if (dir) {
854 pos = search_ref_dir(dir, dirname.buf, dirname.len);
855
856 if (pos >= 0) {
857 /*
858 * We found a directory named "$refname/"
859 * (e.g., "refs/foo/bar/"). It is a problem
860 * iff it contains any ref that is not in
861 * "skip".
862 */
863 struct nonmatching_ref_data data;
864
865 data.skip = skip;
866 data.conflicting_refname = NULL;
867 dir = get_ref_dir(dir->entries[pos]);
868 sort_ref_dir(dir);
869 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
870 strbuf_addf(err, "'%s' exists; cannot create '%s'",
871 data.conflicting_refname, refname);
872 goto cleanup;
873 }
874 }
875 }
876
0845122c
DT
877 extra_refname = find_descendant_ref(dirname.buf, extras, skip);
878 if (extra_refname)
879 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
880 refname, extra_refname);
881 else
882 ret = 0;
7bd9bcf3
MH
883
884cleanup:
885 strbuf_release(&dirname);
886 return ret;
887}
888
889struct packed_ref_cache {
890 struct ref_entry *root;
891
892 /*
893 * Count of references to the data structure in this instance,
65a0a8e5
MH
894 * including the pointer from files_ref_store::packed if any.
895 * The data will not be freed as long as the reference count
896 * is nonzero.
7bd9bcf3
MH
897 */
898 unsigned int referrers;
899
900 /*
901 * Iff the packed-refs file associated with this instance is
902 * currently locked for writing, this points at the associated
903 * lock (which is owned by somebody else). The referrer count
904 * is also incremented when the file is locked and decremented
905 * when it is unlocked.
906 */
907 struct lock_file *lock;
908
909 /* The metadata from when this packed-refs cache was read */
910 struct stat_validity validity;
911};
912
913/*
914 * Future: need to be in "struct repository"
915 * when doing a full libification.
916 */
00eebe35
MH
917struct files_ref_store {
918 struct ref_store base;
32c597e7 919
f57f37e2
NTND
920 char *gitdir;
921 char *gitcommondir;
33dfb9f3
NTND
922 char *packed_refs_path;
923
7bd9bcf3
MH
924 struct ref_entry *loose;
925 struct packed_ref_cache *packed;
00eebe35 926};
7bd9bcf3
MH
927
928/* Lock used for the main packed-refs file: */
929static struct lock_file packlock;
930
931/*
932 * Increment the reference count of *packed_refs.
933 */
934static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
935{
936 packed_refs->referrers++;
937}
938
939/*
940 * Decrease the reference count of *packed_refs. If it goes to zero,
941 * free *packed_refs and return true; otherwise return false.
942 */
943static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
944{
945 if (!--packed_refs->referrers) {
946 free_ref_entry(packed_refs->root);
947 stat_validity_clear(&packed_refs->validity);
948 free(packed_refs);
949 return 1;
950 } else {
951 return 0;
952 }
953}
954
65a0a8e5 955static void clear_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
956{
957 if (refs->packed) {
958 struct packed_ref_cache *packed_refs = refs->packed;
959
960 if (packed_refs->lock)
961 die("internal error: packed-ref cache cleared while locked");
962 refs->packed = NULL;
963 release_packed_ref_cache(packed_refs);
964 }
965}
966
65a0a8e5 967static void clear_loose_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
968{
969 if (refs->loose) {
970 free_ref_entry(refs->loose);
971 refs->loose = NULL;
972 }
973}
974
a2d5156c
JK
975/*
976 * Create a new submodule ref cache and add it to the internal
977 * set of caches.
978 */
5d0bc90e 979static struct ref_store *files_ref_store_create(const char *gitdir)
7bd9bcf3 980{
00eebe35
MH
981 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
982 struct ref_store *ref_store = (struct ref_store *)refs;
f57f37e2 983 struct strbuf sb = STRBUF_INIT;
7bd9bcf3 984
fbfd0a29 985 base_ref_store_init(ref_store, &refs_be_files);
7bd9bcf3 986
f57f37e2
NTND
987 refs->gitdir = xstrdup(gitdir);
988 get_common_dir_noenv(&sb, gitdir);
989 refs->gitcommondir = strbuf_detach(&sb, NULL);
990 strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
991 refs->packed_refs_path = strbuf_detach(&sb, NULL);
7bd9bcf3 992
00eebe35 993 return ref_store;
a2d5156c 994}
7bd9bcf3 995
32c597e7
MH
996/*
997 * Die if refs is for a submodule (i.e., not for the main repository).
998 * caller is used in any necessary error messages.
999 */
1000static void files_assert_main_repository(struct files_ref_store *refs,
1001 const char *caller)
1002{
5d0bc90e 1003 /* This function is to be fixed up in the next patch */
32c597e7
MH
1004}
1005
a2d5156c 1006/*
00eebe35
MH
1007 * Downcast ref_store to files_ref_store. Die if ref_store is not a
1008 * files_ref_store. If submodule_allowed is not true, then also die if
1009 * files_ref_store is for a submodule (i.e., not for the main
1010 * repository). caller is used in any necessary error messages.
a2d5156c 1011 */
00eebe35
MH
1012static struct files_ref_store *files_downcast(
1013 struct ref_store *ref_store, int submodule_allowed,
1014 const char *caller)
a2d5156c 1015{
32c597e7
MH
1016 struct files_ref_store *refs;
1017
00eebe35
MH
1018 if (ref_store->be != &refs_be_files)
1019 die("BUG: ref_store is type \"%s\" not \"files\" in %s",
1020 ref_store->be->name, caller);
2eed2780 1021
32c597e7
MH
1022 refs = (struct files_ref_store *)ref_store;
1023
00eebe35 1024 if (!submodule_allowed)
32c597e7 1025 files_assert_main_repository(refs, caller);
2eed2780 1026
32c597e7 1027 return refs;
7bd9bcf3
MH
1028}
1029
1030/* The length of a peeled reference line in packed-refs, including EOL: */
1031#define PEELED_LINE_LENGTH 42
1032
1033/*
1034 * The packed-refs header line that we write out. Perhaps other
1035 * traits will be added later. The trailing space is required.
1036 */
1037static const char PACKED_REFS_HEADER[] =
1038 "# pack-refs with: peeled fully-peeled \n";
1039
1040/*
1041 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1042 * Return a pointer to the refname within the line (null-terminated),
1043 * or NULL if there was a problem.
1044 */
1045static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1046{
1047 const char *ref;
1048
1049 /*
1050 * 42: the answer to everything.
1051 *
1052 * In this case, it happens to be the answer to
1053 * 40 (length of sha1 hex representation)
1054 * +1 (space in between hex and name)
1055 * +1 (newline at the end of the line)
1056 */
1057 if (line->len <= 42)
1058 return NULL;
1059
1060 if (get_sha1_hex(line->buf, sha1) < 0)
1061 return NULL;
1062 if (!isspace(line->buf[40]))
1063 return NULL;
1064
1065 ref = line->buf + 41;
1066 if (isspace(*ref))
1067 return NULL;
1068
1069 if (line->buf[line->len - 1] != '\n')
1070 return NULL;
1071 line->buf[--line->len] = 0;
1072
1073 return ref;
1074}
1075
1076/*
1077 * Read f, which is a packed-refs file, into dir.
1078 *
1079 * A comment line of the form "# pack-refs with: " may contain zero or
1080 * more traits. We interpret the traits as follows:
1081 *
1082 * No traits:
1083 *
1084 * Probably no references are peeled. But if the file contains a
1085 * peeled value for a reference, we will use it.
1086 *
1087 * peeled:
1088 *
1089 * References under "refs/tags/", if they *can* be peeled, *are*
1090 * peeled in this file. References outside of "refs/tags/" are
1091 * probably not peeled even if they could have been, but if we find
1092 * a peeled value for such a reference we will use it.
1093 *
1094 * fully-peeled:
1095 *
1096 * All references in the file that can be peeled are peeled.
1097 * Inversely (and this is more important), any references in the
1098 * file for which no peeled value is recorded is not peelable. This
1099 * trait should typically be written alongside "peeled" for
1100 * compatibility with older clients, but we do not require it
1101 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1102 */
1103static void read_packed_refs(FILE *f, struct ref_dir *dir)
1104{
1105 struct ref_entry *last = NULL;
1106 struct strbuf line = STRBUF_INIT;
1107 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1108
1109 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1110 unsigned char sha1[20];
1111 const char *refname;
1112 const char *traits;
1113
1114 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1115 if (strstr(traits, " fully-peeled "))
1116 peeled = PEELED_FULLY;
1117 else if (strstr(traits, " peeled "))
1118 peeled = PEELED_TAGS;
1119 /* perhaps other traits later as well */
1120 continue;
1121 }
1122
1123 refname = parse_ref_line(&line, sha1);
1124 if (refname) {
1125 int flag = REF_ISPACKED;
1126
1127 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1128 if (!refname_is_safe(refname))
1129 die("packed refname is dangerous: %s", refname);
1130 hashclr(sha1);
1131 flag |= REF_BAD_NAME | REF_ISBROKEN;
1132 }
1133 last = create_ref_entry(refname, sha1, flag, 0);
1134 if (peeled == PEELED_FULLY ||
1135 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1136 last->flag |= REF_KNOWS_PEELED;
1137 add_ref(dir, last);
1138 continue;
1139 }
1140 if (last &&
1141 line.buf[0] == '^' &&
1142 line.len == PEELED_LINE_LENGTH &&
1143 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1144 !get_sha1_hex(line.buf + 1, sha1)) {
1145 hashcpy(last->u.value.peeled.hash, sha1);
1146 /*
1147 * Regardless of what the file header said,
1148 * we definitely know the value of *this*
1149 * reference:
1150 */
1151 last->flag |= REF_KNOWS_PEELED;
1152 }
1153 }
1154
1155 strbuf_release(&line);
1156}
1157
33dfb9f3
NTND
1158static const char *files_packed_refs_path(struct files_ref_store *refs)
1159{
1160 return refs->packed_refs_path;
1161}
1162
802de3da
NTND
1163static void files_reflog_path(struct files_ref_store *refs,
1164 struct strbuf *sb,
1165 const char *refname)
1166{
1167 if (!refname) {
f57f37e2
NTND
1168 /*
1169 * FIXME: of course this is wrong in multi worktree
1170 * setting. To be fixed real soon.
1171 */
1172 strbuf_addf(sb, "%s/logs", refs->gitcommondir);
802de3da
NTND
1173 return;
1174 }
1175
f57f37e2
NTND
1176 switch (ref_type(refname)) {
1177 case REF_TYPE_PER_WORKTREE:
1178 case REF_TYPE_PSEUDOREF:
1179 strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
1180 break;
1181 case REF_TYPE_NORMAL:
1182 strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
1183 break;
1184 default:
1185 die("BUG: unknown ref type %d of ref %s",
1186 ref_type(refname), refname);
1187 }
802de3da
NTND
1188}
1189
19e02f4f
NTND
1190static void files_ref_path(struct files_ref_store *refs,
1191 struct strbuf *sb,
1192 const char *refname)
1193{
f57f37e2
NTND
1194 switch (ref_type(refname)) {
1195 case REF_TYPE_PER_WORKTREE:
1196 case REF_TYPE_PSEUDOREF:
1197 strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
1198 break;
1199 case REF_TYPE_NORMAL:
1200 strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
1201 break;
1202 default:
1203 die("BUG: unknown ref type %d of ref %s",
1204 ref_type(refname), refname);
1205 }
19e02f4f
NTND
1206}
1207
7bd9bcf3 1208/*
65a0a8e5
MH
1209 * Get the packed_ref_cache for the specified files_ref_store,
1210 * creating it if necessary.
7bd9bcf3 1211 */
65a0a8e5 1212static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3 1213{
33dfb9f3 1214 const char *packed_refs_file = files_packed_refs_path(refs);
7bd9bcf3
MH
1215
1216 if (refs->packed &&
1217 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1218 clear_packed_ref_cache(refs);
1219
1220 if (!refs->packed) {
1221 FILE *f;
1222
1223 refs->packed = xcalloc(1, sizeof(*refs->packed));
1224 acquire_packed_ref_cache(refs->packed);
1225 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1226 f = fopen(packed_refs_file, "r");
1227 if (f) {
1228 stat_validity_update(&refs->packed->validity, fileno(f));
1229 read_packed_refs(f, get_ref_dir(refs->packed->root));
1230 fclose(f);
1231 }
1232 }
7bd9bcf3
MH
1233 return refs->packed;
1234}
1235
1236static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1237{
1238 return get_ref_dir(packed_ref_cache->root);
1239}
1240
65a0a8e5 1241static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1242{
1243 return get_packed_ref_dir(get_packed_ref_cache(refs));
1244}
1245
1246/*
1247 * Add a reference to the in-memory packed reference cache. This may
1248 * only be called while the packed-refs file is locked (see
1249 * lock_packed_refs()). To actually write the packed-refs file, call
1250 * commit_packed_refs().
1251 */
d99825ab
MH
1252static void add_packed_ref(struct files_ref_store *refs,
1253 const char *refname, const unsigned char *sha1)
7bd9bcf3 1254{
00eebe35 1255 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
1256
1257 if (!packed_ref_cache->lock)
1258 die("internal error: packed refs not locked");
1259 add_ref(get_packed_ref_dir(packed_ref_cache),
1260 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1261}
1262
1263/*
1264 * Read the loose references from the namespace dirname into dir
1265 * (without recursing). dirname must end with '/'. dir must be the
1266 * directory entry corresponding to dirname.
1267 */
1268static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1269{
65a0a8e5 1270 struct files_ref_store *refs = dir->ref_store;
7bd9bcf3
MH
1271 DIR *d;
1272 struct dirent *de;
1273 int dirnamelen = strlen(dirname);
1274 struct strbuf refname;
1275 struct strbuf path = STRBUF_INIT;
1276 size_t path_baselen;
1277
19e02f4f 1278 files_ref_path(refs, &path, dirname);
7bd9bcf3
MH
1279 path_baselen = path.len;
1280
1281 d = opendir(path.buf);
1282 if (!d) {
1283 strbuf_release(&path);
1284 return;
1285 }
1286
1287 strbuf_init(&refname, dirnamelen + 257);
1288 strbuf_add(&refname, dirname, dirnamelen);
1289
1290 while ((de = readdir(d)) != NULL) {
1291 unsigned char sha1[20];
1292 struct stat st;
1293 int flag;
1294
1295 if (de->d_name[0] == '.')
1296 continue;
1297 if (ends_with(de->d_name, ".lock"))
1298 continue;
1299 strbuf_addstr(&refname, de->d_name);
1300 strbuf_addstr(&path, de->d_name);
1301 if (stat(path.buf, &st) < 0) {
1302 ; /* silently ignore */
1303 } else if (S_ISDIR(st.st_mode)) {
1304 strbuf_addch(&refname, '/');
1305 add_entry_to_dir(dir,
1306 create_dir_entry(refs, refname.buf,
1307 refname.len, 1));
1308 } else {
3c0cb0cb
MH
1309 if (!resolve_ref_recursively(&refs->base,
1310 refname.buf,
1311 RESOLVE_REF_READING,
1312 sha1, &flag)) {
7bd9bcf3
MH
1313 hashclr(sha1);
1314 flag |= REF_ISBROKEN;
1315 } else if (is_null_sha1(sha1)) {
1316 /*
1317 * It is so astronomically unlikely
1318 * that NULL_SHA1 is the SHA-1 of an
1319 * actual object that we consider its
1320 * appearance in a loose reference
1321 * file to be repo corruption
1322 * (probably due to a software bug).
1323 */
1324 flag |= REF_ISBROKEN;
1325 }
1326
1327 if (check_refname_format(refname.buf,
1328 REFNAME_ALLOW_ONELEVEL)) {
1329 if (!refname_is_safe(refname.buf))
1330 die("loose refname is dangerous: %s", refname.buf);
1331 hashclr(sha1);
1332 flag |= REF_BAD_NAME | REF_ISBROKEN;
1333 }
1334 add_entry_to_dir(dir,
1335 create_ref_entry(refname.buf, sha1, flag, 0));
1336 }
1337 strbuf_setlen(&refname, dirnamelen);
1338 strbuf_setlen(&path, path_baselen);
1339 }
1340 strbuf_release(&refname);
1341 strbuf_release(&path);
1342 closedir(d);
1343}
1344
65a0a8e5 1345static struct ref_dir *get_loose_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1346{
1347 if (!refs->loose) {
1348 /*
1349 * Mark the top-level directory complete because we
1350 * are about to read the only subdirectory that can
1351 * hold references:
1352 */
1353 refs->loose = create_dir_entry(refs, "", 0, 0);
1354 /*
1355 * Create an incomplete entry for "refs/":
1356 */
1357 add_entry_to_dir(get_ref_dir(refs->loose),
1358 create_dir_entry(refs, "refs/", 5, 1));
1359 }
1360 return get_ref_dir(refs->loose);
1361}
1362
7bd9bcf3
MH
1363/*
1364 * Return the ref_entry for the given refname from the packed
1365 * references. If it does not exist, return NULL.
1366 */
f0d21efc
MH
1367static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
1368 const char *refname)
7bd9bcf3 1369{
00eebe35 1370 return find_ref(get_packed_refs(refs), refname);
7bd9bcf3
MH
1371}
1372
1373/*
419c6f4c 1374 * A loose ref file doesn't exist; check for a packed ref.
7bd9bcf3 1375 */
611118d0
MH
1376static int resolve_packed_ref(struct files_ref_store *refs,
1377 const char *refname,
1378 unsigned char *sha1, unsigned int *flags)
7bd9bcf3
MH
1379{
1380 struct ref_entry *entry;
1381
1382 /*
1383 * The loose reference file does not exist; check for a packed
1384 * reference.
1385 */
f0d21efc 1386 entry = get_packed_ref(refs, refname);
7bd9bcf3
MH
1387 if (entry) {
1388 hashcpy(sha1, entry->u.value.oid.hash);
a70a93b7 1389 *flags |= REF_ISPACKED;
7bd9bcf3
MH
1390 return 0;
1391 }
419c6f4c
MH
1392 /* refname is not a packed reference. */
1393 return -1;
7bd9bcf3
MH
1394}
1395
e1e33b72
MH
1396static int files_read_raw_ref(struct ref_store *ref_store,
1397 const char *refname, unsigned char *sha1,
1398 struct strbuf *referent, unsigned int *type)
7bd9bcf3 1399{
4308651c 1400 struct files_ref_store *refs =
34c7ad8f 1401 files_downcast(ref_store, 1, "read_raw_ref");
42a38cf7
MH
1402 struct strbuf sb_contents = STRBUF_INIT;
1403 struct strbuf sb_path = STRBUF_INIT;
7048653a
DT
1404 const char *path;
1405 const char *buf;
1406 struct stat st;
1407 int fd;
42a38cf7
MH
1408 int ret = -1;
1409 int save_errno;
e8c42cb9 1410 int remaining_retries = 3;
7bd9bcf3 1411
fa96ea1b 1412 *type = 0;
42a38cf7 1413 strbuf_reset(&sb_path);
34c7ad8f 1414
19e02f4f 1415 files_ref_path(refs, &sb_path, refname);
34c7ad8f 1416
42a38cf7 1417 path = sb_path.buf;
7bd9bcf3 1418
7048653a
DT
1419stat_ref:
1420 /*
1421 * We might have to loop back here to avoid a race
1422 * condition: first we lstat() the file, then we try
1423 * to read it as a link or as a file. But if somebody
1424 * changes the type of the file (file <-> directory
1425 * <-> symlink) between the lstat() and reading, then
1426 * we don't want to report that as an error but rather
1427 * try again starting with the lstat().
e8c42cb9
JK
1428 *
1429 * We'll keep a count of the retries, though, just to avoid
1430 * any confusing situation sending us into an infinite loop.
7048653a 1431 */
7bd9bcf3 1432
e8c42cb9
JK
1433 if (remaining_retries-- <= 0)
1434 goto out;
1435
7048653a
DT
1436 if (lstat(path, &st) < 0) {
1437 if (errno != ENOENT)
42a38cf7 1438 goto out;
611118d0 1439 if (resolve_packed_ref(refs, refname, sha1, type)) {
7048653a 1440 errno = ENOENT;
42a38cf7 1441 goto out;
7bd9bcf3 1442 }
42a38cf7
MH
1443 ret = 0;
1444 goto out;
7bd9bcf3 1445 }
7bd9bcf3 1446
7048653a
DT
1447 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1448 if (S_ISLNK(st.st_mode)) {
42a38cf7
MH
1449 strbuf_reset(&sb_contents);
1450 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
7048653a 1451 if (errno == ENOENT || errno == EINVAL)
7bd9bcf3
MH
1452 /* inconsistent with lstat; retry */
1453 goto stat_ref;
1454 else
42a38cf7 1455 goto out;
7bd9bcf3 1456 }
42a38cf7
MH
1457 if (starts_with(sb_contents.buf, "refs/") &&
1458 !check_refname_format(sb_contents.buf, 0)) {
92b38093 1459 strbuf_swap(&sb_contents, referent);
3a0b6b9a 1460 *type |= REF_ISSYMREF;
42a38cf7
MH
1461 ret = 0;
1462 goto out;
7bd9bcf3 1463 }
3f7bd767
JK
1464 /*
1465 * It doesn't look like a refname; fall through to just
1466 * treating it like a non-symlink, and reading whatever it
1467 * points to.
1468 */
7048653a 1469 }
7bd9bcf3 1470
7048653a
DT
1471 /* Is it a directory? */
1472 if (S_ISDIR(st.st_mode)) {
e167a567
MH
1473 /*
1474 * Even though there is a directory where the loose
1475 * ref is supposed to be, there could still be a
1476 * packed ref:
1477 */
611118d0 1478 if (resolve_packed_ref(refs, refname, sha1, type)) {
e167a567
MH
1479 errno = EISDIR;
1480 goto out;
1481 }
1482 ret = 0;
42a38cf7 1483 goto out;
7048653a
DT
1484 }
1485
1486 /*
1487 * Anything else, just open it and try to use it as
1488 * a ref
1489 */
1490 fd = open(path, O_RDONLY);
1491 if (fd < 0) {
3f7bd767 1492 if (errno == ENOENT && !S_ISLNK(st.st_mode))
7048653a
DT
1493 /* inconsistent with lstat; retry */
1494 goto stat_ref;
1495 else
42a38cf7 1496 goto out;
7048653a 1497 }
42a38cf7
MH
1498 strbuf_reset(&sb_contents);
1499 if (strbuf_read(&sb_contents, fd, 256) < 0) {
7048653a
DT
1500 int save_errno = errno;
1501 close(fd);
1502 errno = save_errno;
42a38cf7 1503 goto out;
7048653a
DT
1504 }
1505 close(fd);
42a38cf7
MH
1506 strbuf_rtrim(&sb_contents);
1507 buf = sb_contents.buf;
7048653a
DT
1508 if (starts_with(buf, "ref:")) {
1509 buf += 4;
7bd9bcf3
MH
1510 while (isspace(*buf))
1511 buf++;
7048653a 1512
92b38093
MH
1513 strbuf_reset(referent);
1514 strbuf_addstr(referent, buf);
3a0b6b9a 1515 *type |= REF_ISSYMREF;
42a38cf7
MH
1516 ret = 0;
1517 goto out;
7bd9bcf3 1518 }
7bd9bcf3 1519
7048653a
DT
1520 /*
1521 * Please note that FETCH_HEAD has additional
1522 * data after the sha.
1523 */
1524 if (get_sha1_hex(buf, sha1) ||
1525 (buf[40] != '\0' && !isspace(buf[40]))) {
3a0b6b9a 1526 *type |= REF_ISBROKEN;
7048653a 1527 errno = EINVAL;
42a38cf7 1528 goto out;
7048653a
DT
1529 }
1530
42a38cf7 1531 ret = 0;
7bd9bcf3 1532
42a38cf7
MH
1533out:
1534 save_errno = errno;
7bd9bcf3
MH
1535 strbuf_release(&sb_path);
1536 strbuf_release(&sb_contents);
42a38cf7 1537 errno = save_errno;
7bd9bcf3
MH
1538 return ret;
1539}
1540
8415d247
MH
1541static void unlock_ref(struct ref_lock *lock)
1542{
1543 /* Do not free lock->lk -- atexit() still looks at them */
1544 if (lock->lk)
1545 rollback_lock_file(lock->lk);
1546 free(lock->ref_name);
8415d247
MH
1547 free(lock);
1548}
1549
92b1551b
MH
1550/*
1551 * Lock refname, without following symrefs, and set *lock_p to point
1552 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
1553 * and type similarly to read_raw_ref().
1554 *
1555 * The caller must verify that refname is a "safe" reference name (in
1556 * the sense of refname_is_safe()) before calling this function.
1557 *
1558 * If the reference doesn't already exist, verify that refname doesn't
1559 * have a D/F conflict with any existing references. extras and skip
1560 * are passed to verify_refname_available_dir() for this check.
1561 *
1562 * If mustexist is not set and the reference is not found or is
1563 * broken, lock the reference anyway but clear sha1.
1564 *
1565 * Return 0 on success. On failure, write an error message to err and
1566 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
1567 *
1568 * Implementation note: This function is basically
1569 *
1570 * lock reference
1571 * read_raw_ref()
1572 *
1573 * but it includes a lot more code to
1574 * - Deal with possible races with other processes
1575 * - Avoid calling verify_refname_available_dir() when it can be
1576 * avoided, namely if we were successfully able to read the ref
1577 * - Generate informative error messages in the case of failure
1578 */
f7b0a987
MH
1579static int lock_raw_ref(struct files_ref_store *refs,
1580 const char *refname, int mustexist,
92b1551b
MH
1581 const struct string_list *extras,
1582 const struct string_list *skip,
1583 struct ref_lock **lock_p,
1584 struct strbuf *referent,
1585 unsigned int *type,
1586 struct strbuf *err)
1587{
1588 struct ref_lock *lock;
1589 struct strbuf ref_file = STRBUF_INIT;
1590 int attempts_remaining = 3;
1591 int ret = TRANSACTION_GENERIC_ERROR;
1592
1593 assert(err);
32c597e7 1594 files_assert_main_repository(refs, "lock_raw_ref");
f7b0a987 1595
92b1551b
MH
1596 *type = 0;
1597
1598 /* First lock the file so it can't change out from under us. */
1599
1600 *lock_p = lock = xcalloc(1, sizeof(*lock));
1601
1602 lock->ref_name = xstrdup(refname);
19e02f4f 1603 files_ref_path(refs, &ref_file, refname);
92b1551b
MH
1604
1605retry:
1606 switch (safe_create_leading_directories(ref_file.buf)) {
1607 case SCLD_OK:
1608 break; /* success */
1609 case SCLD_EXISTS:
1610 /*
1611 * Suppose refname is "refs/foo/bar". We just failed
1612 * to create the containing directory, "refs/foo",
1613 * because there was a non-directory in the way. This
1614 * indicates a D/F conflict, probably because of
1615 * another reference such as "refs/foo". There is no
1616 * reason to expect this error to be transitory.
1617 */
1618 if (verify_refname_available(refname, extras, skip, err)) {
1619 if (mustexist) {
1620 /*
1621 * To the user the relevant error is
1622 * that the "mustexist" reference is
1623 * missing:
1624 */
1625 strbuf_reset(err);
1626 strbuf_addf(err, "unable to resolve reference '%s'",
1627 refname);
1628 } else {
1629 /*
1630 * The error message set by
1631 * verify_refname_available_dir() is OK.
1632 */
1633 ret = TRANSACTION_NAME_CONFLICT;
1634 }
1635 } else {
1636 /*
1637 * The file that is in the way isn't a loose
1638 * reference. Report it as a low-level
1639 * failure.
1640 */
1641 strbuf_addf(err, "unable to create lock file %s.lock; "
1642 "non-directory in the way",
1643 ref_file.buf);
1644 }
1645 goto error_return;
1646 case SCLD_VANISHED:
1647 /* Maybe another process was tidying up. Try again. */
1648 if (--attempts_remaining > 0)
1649 goto retry;
1650 /* fall through */
1651 default:
1652 strbuf_addf(err, "unable to create directory for %s",
1653 ref_file.buf);
1654 goto error_return;
1655 }
1656
1657 if (!lock->lk)
1658 lock->lk = xcalloc(1, sizeof(struct lock_file));
1659
1660 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
1661 if (errno == ENOENT && --attempts_remaining > 0) {
1662 /*
1663 * Maybe somebody just deleted one of the
1664 * directories leading to ref_file. Try
1665 * again:
1666 */
1667 goto retry;
1668 } else {
1669 unable_to_lock_message(ref_file.buf, errno, err);
1670 goto error_return;
1671 }
1672 }
1673
1674 /*
1675 * Now we hold the lock and can read the reference without
1676 * fear that its value will change.
1677 */
1678
f7b0a987 1679 if (files_read_raw_ref(&refs->base, refname,
e1e33b72 1680 lock->old_oid.hash, referent, type)) {
92b1551b
MH
1681 if (errno == ENOENT) {
1682 if (mustexist) {
1683 /* Garden variety missing reference. */
1684 strbuf_addf(err, "unable to resolve reference '%s'",
1685 refname);
1686 goto error_return;
1687 } else {
1688 /*
1689 * Reference is missing, but that's OK. We
1690 * know that there is not a conflict with
1691 * another loose reference because
1692 * (supposing that we are trying to lock
1693 * reference "refs/foo/bar"):
1694 *
1695 * - We were successfully able to create
1696 * the lockfile refs/foo/bar.lock, so we
1697 * know there cannot be a loose reference
1698 * named "refs/foo".
1699 *
1700 * - We got ENOENT and not EISDIR, so we
1701 * know that there cannot be a loose
1702 * reference named "refs/foo/bar/baz".
1703 */
1704 }
1705 } else if (errno == EISDIR) {
1706 /*
1707 * There is a directory in the way. It might have
1708 * contained references that have been deleted. If
1709 * we don't require that the reference already
1710 * exists, try to remove the directory so that it
1711 * doesn't cause trouble when we want to rename the
1712 * lockfile into place later.
1713 */
1714 if (mustexist) {
1715 /* Garden variety missing reference. */
1716 strbuf_addf(err, "unable to resolve reference '%s'",
1717 refname);
1718 goto error_return;
1719 } else if (remove_dir_recursively(&ref_file,
1720 REMOVE_DIR_EMPTY_ONLY)) {
1721 if (verify_refname_available_dir(
1722 refname, extras, skip,
00eebe35 1723 get_loose_refs(refs),
92b1551b
MH
1724 err)) {
1725 /*
1726 * The error message set by
1727 * verify_refname_available() is OK.
1728 */
1729 ret = TRANSACTION_NAME_CONFLICT;
1730 goto error_return;
1731 } else {
1732 /*
1733 * We can't delete the directory,
1734 * but we also don't know of any
1735 * references that it should
1736 * contain.
1737 */
1738 strbuf_addf(err, "there is a non-empty directory '%s' "
1739 "blocking reference '%s'",
1740 ref_file.buf, refname);
1741 goto error_return;
1742 }
1743 }
1744 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
1745 strbuf_addf(err, "unable to resolve reference '%s': "
1746 "reference broken", refname);
1747 goto error_return;
1748 } else {
1749 strbuf_addf(err, "unable to resolve reference '%s': %s",
1750 refname, strerror(errno));
1751 goto error_return;
1752 }
1753
1754 /*
1755 * If the ref did not exist and we are creating it,
1756 * make sure there is no existing packed ref whose
1757 * name begins with our refname, nor a packed ref
1758 * whose name is a proper prefix of our refname.
1759 */
1760 if (verify_refname_available_dir(
1761 refname, extras, skip,
00eebe35 1762 get_packed_refs(refs),
92b1551b
MH
1763 err)) {
1764 goto error_return;
1765 }
1766 }
1767
1768 ret = 0;
1769 goto out;
1770
1771error_return:
1772 unlock_ref(lock);
1773 *lock_p = NULL;
1774
1775out:
1776 strbuf_release(&ref_file);
1777 return ret;
1778}
1779
7bd9bcf3
MH
1780/*
1781 * Peel the entry (if possible) and return its new peel_status. If
1782 * repeel is true, re-peel the entry even if there is an old peeled
1783 * value that is already stored in it.
1784 *
1785 * It is OK to call this function with a packed reference entry that
1786 * might be stale and might even refer to an object that has since
1787 * been garbage-collected. In such a case, if the entry has
1788 * REF_KNOWS_PEELED then leave the status unchanged and return
1789 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1790 */
1791static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1792{
1793 enum peel_status status;
1794
1795 if (entry->flag & REF_KNOWS_PEELED) {
1796 if (repeel) {
1797 entry->flag &= ~REF_KNOWS_PEELED;
1798 oidclr(&entry->u.value.peeled);
1799 } else {
1800 return is_null_oid(&entry->u.value.peeled) ?
1801 PEEL_NON_TAG : PEEL_PEELED;
1802 }
1803 }
1804 if (entry->flag & REF_ISBROKEN)
1805 return PEEL_BROKEN;
1806 if (entry->flag & REF_ISSYMREF)
1807 return PEEL_IS_SYMREF;
1808
1809 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1810 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1811 entry->flag |= REF_KNOWS_PEELED;
1812 return status;
1813}
1814
bd427cf2
MH
1815static int files_peel_ref(struct ref_store *ref_store,
1816 const char *refname, unsigned char *sha1)
7bd9bcf3 1817{
bd427cf2 1818 struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
7bd9bcf3
MH
1819 int flag;
1820 unsigned char base[20];
1821
4c4de895
MH
1822 if (current_ref_iter && current_ref_iter->refname == refname) {
1823 struct object_id peeled;
1824
1825 if (ref_iterator_peel(current_ref_iter, &peeled))
7bd9bcf3 1826 return -1;
4c4de895 1827 hashcpy(sha1, peeled.hash);
7bd9bcf3
MH
1828 return 0;
1829 }
1830
1831 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1832 return -1;
1833
1834 /*
1835 * If the reference is packed, read its ref_entry from the
1836 * cache in the hope that we already know its peeled value.
1837 * We only try this optimization on packed references because
1838 * (a) forcing the filling of the loose reference cache could
1839 * be expensive and (b) loose references anyway usually do not
1840 * have REF_KNOWS_PEELED.
1841 */
1842 if (flag & REF_ISPACKED) {
f0d21efc 1843 struct ref_entry *r = get_packed_ref(refs, refname);
7bd9bcf3
MH
1844 if (r) {
1845 if (peel_entry(r, 0))
1846 return -1;
1847 hashcpy(sha1, r->u.value.peeled.hash);
1848 return 0;
1849 }
1850 }
1851
1852 return peel_object(base, sha1);
1853}
1854
3bc581b9
MH
1855struct files_ref_iterator {
1856 struct ref_iterator base;
1857
7bd9bcf3 1858 struct packed_ref_cache *packed_ref_cache;
3bc581b9
MH
1859 struct ref_iterator *iter0;
1860 unsigned int flags;
1861};
7bd9bcf3 1862
3bc581b9
MH
1863static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
1864{
1865 struct files_ref_iterator *iter =
1866 (struct files_ref_iterator *)ref_iterator;
1867 int ok;
7bd9bcf3 1868
3bc581b9 1869 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
0c09ec07
DT
1870 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
1871 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
1872 continue;
1873
3bc581b9
MH
1874 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
1875 !ref_resolves_to_object(iter->iter0->refname,
1876 iter->iter0->oid,
1877 iter->iter0->flags))
1878 continue;
1879
1880 iter->base.refname = iter->iter0->refname;
1881 iter->base.oid = iter->iter0->oid;
1882 iter->base.flags = iter->iter0->flags;
1883 return ITER_OK;
7bd9bcf3
MH
1884 }
1885
3bc581b9
MH
1886 iter->iter0 = NULL;
1887 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
1888 ok = ITER_ERROR;
1889
1890 return ok;
7bd9bcf3
MH
1891}
1892
3bc581b9
MH
1893static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
1894 struct object_id *peeled)
7bd9bcf3 1895{
3bc581b9
MH
1896 struct files_ref_iterator *iter =
1897 (struct files_ref_iterator *)ref_iterator;
93770590 1898
3bc581b9
MH
1899 return ref_iterator_peel(iter->iter0, peeled);
1900}
1901
1902static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
1903{
1904 struct files_ref_iterator *iter =
1905 (struct files_ref_iterator *)ref_iterator;
1906 int ok = ITER_DONE;
1907
1908 if (iter->iter0)
1909 ok = ref_iterator_abort(iter->iter0);
1910
1911 release_packed_ref_cache(iter->packed_ref_cache);
1912 base_ref_iterator_free(ref_iterator);
1913 return ok;
1914}
1915
1916static struct ref_iterator_vtable files_ref_iterator_vtable = {
1917 files_ref_iterator_advance,
1918 files_ref_iterator_peel,
1919 files_ref_iterator_abort
1920};
1921
1a769003 1922static struct ref_iterator *files_ref_iterator_begin(
37b6f6d5 1923 struct ref_store *ref_store,
3bc581b9
MH
1924 const char *prefix, unsigned int flags)
1925{
00eebe35 1926 struct files_ref_store *refs =
37b6f6d5 1927 files_downcast(ref_store, 1, "ref_iterator_begin");
3bc581b9
MH
1928 struct ref_dir *loose_dir, *packed_dir;
1929 struct ref_iterator *loose_iter, *packed_iter;
1930 struct files_ref_iterator *iter;
1931 struct ref_iterator *ref_iterator;
1932
7bd9bcf3
MH
1933 if (ref_paranoia < 0)
1934 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1935 if (ref_paranoia)
3bc581b9
MH
1936 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1937
1938 iter = xcalloc(1, sizeof(*iter));
1939 ref_iterator = &iter->base;
1940 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
1941
1942 /*
1943 * We must make sure that all loose refs are read before
1944 * accessing the packed-refs file; this avoids a race
1945 * condition if loose refs are migrated to the packed-refs
1946 * file by a simultaneous process, but our in-memory view is
1947 * from before the migration. We ensure this as follows:
1948 * First, we call prime_ref_dir(), which pre-reads the loose
1949 * references for the subtree into the cache. (If they've
1950 * already been read, that's OK; we only need to guarantee
1951 * that they're read before the packed refs, not *how much*
1952 * before.) After that, we call get_packed_ref_cache(), which
1953 * internally checks whether the packed-ref cache is up to
1954 * date with what is on disk, and re-reads it if not.
1955 */
1956
1957 loose_dir = get_loose_refs(refs);
1958
1959 if (prefix && *prefix)
1960 loose_dir = find_containing_dir(loose_dir, prefix, 0);
7bd9bcf3 1961
3bc581b9
MH
1962 if (loose_dir) {
1963 prime_ref_dir(loose_dir);
1964 loose_iter = cache_ref_iterator_begin(loose_dir);
1965 } else {
1966 /* There's nothing to iterate over. */
1967 loose_iter = empty_ref_iterator_begin();
1968 }
1969
1970 iter->packed_ref_cache = get_packed_ref_cache(refs);
1971 acquire_packed_ref_cache(iter->packed_ref_cache);
1972 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);
1973
1974 if (prefix && *prefix)
1975 packed_dir = find_containing_dir(packed_dir, prefix, 0);
1976
1977 if (packed_dir) {
1978 packed_iter = cache_ref_iterator_begin(packed_dir);
1979 } else {
1980 /* There's nothing to iterate over. */
1981 packed_iter = empty_ref_iterator_begin();
1982 }
1983
1984 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
1985 iter->flags = flags;
1986
1987 return ref_iterator;
7bd9bcf3
MH
1988}
1989
7bd9bcf3
MH
1990/*
1991 * Verify that the reference locked by lock has the value old_sha1.
1992 * Fail if the reference doesn't exist and mustexist is set. Return 0
1993 * on success. On error, write an error message to err, set errno, and
1994 * return a negative value.
1995 */
1996static int verify_lock(struct ref_lock *lock,
1997 const unsigned char *old_sha1, int mustexist,
1998 struct strbuf *err)
1999{
2000 assert(err);
2001
2002 if (read_ref_full(lock->ref_name,
2003 mustexist ? RESOLVE_REF_READING : 0,
2004 lock->old_oid.hash, NULL)) {
6294dcb4
JK
2005 if (old_sha1) {
2006 int save_errno = errno;
0568c8e9 2007 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
6294dcb4
JK
2008 errno = save_errno;
2009 return -1;
2010 } else {
c368dde9 2011 oidclr(&lock->old_oid);
6294dcb4
JK
2012 return 0;
2013 }
7bd9bcf3 2014 }
6294dcb4 2015 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
0568c8e9 2016 strbuf_addf(err, "ref '%s' is at %s but expected %s",
7bd9bcf3 2017 lock->ref_name,
c368dde9 2018 oid_to_hex(&lock->old_oid),
7bd9bcf3
MH
2019 sha1_to_hex(old_sha1));
2020 errno = EBUSY;
2021 return -1;
2022 }
2023 return 0;
2024}
2025
2026static int remove_empty_directories(struct strbuf *path)
2027{
2028 /*
2029 * we want to create a file but there is a directory there;
2030 * if that is an empty directory (or a directory that contains
2031 * only empty directories), remove them.
2032 */
2033 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
2034}
2035
3b5d3c98
MH
2036static int create_reflock(const char *path, void *cb)
2037{
2038 struct lock_file *lk = cb;
2039
2040 return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;
2041}
2042
7bd9bcf3
MH
2043/*
2044 * Locks a ref returning the lock on success and NULL on failure.
2045 * On failure errno is set to something meaningful.
2046 */
7eb27cdf
MH
2047static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
2048 const char *refname,
7bd9bcf3
MH
2049 const unsigned char *old_sha1,
2050 const struct string_list *extras,
2051 const struct string_list *skip,
bcb497d0 2052 unsigned int flags, int *type,
7bd9bcf3
MH
2053 struct strbuf *err)
2054{
2055 struct strbuf ref_file = STRBUF_INIT;
7bd9bcf3
MH
2056 struct ref_lock *lock;
2057 int last_errno = 0;
7bd9bcf3 2058 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
7a418f3a 2059 int resolve_flags = RESOLVE_REF_NO_RECURSE;
7a418f3a 2060 int resolved;
7bd9bcf3 2061
32c597e7 2062 files_assert_main_repository(refs, "lock_ref_sha1_basic");
7bd9bcf3
MH
2063 assert(err);
2064
2065 lock = xcalloc(1, sizeof(struct ref_lock));
2066
2067 if (mustexist)
2068 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 2069 if (flags & REF_DELETING)
7bd9bcf3 2070 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
7bd9bcf3 2071
19e02f4f 2072 files_ref_path(refs, &ref_file, refname);
7a418f3a
MH
2073 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2074 lock->old_oid.hash, type);
2075 if (!resolved && errno == EISDIR) {
7bd9bcf3
MH
2076 /*
2077 * we are trying to lock foo but we used to
2078 * have foo/bar which now does not exist;
2079 * it is normal for the empty directory 'foo'
2080 * to remain.
2081 */
7a418f3a 2082 if (remove_empty_directories(&ref_file)) {
7bd9bcf3 2083 last_errno = errno;
00eebe35
MH
2084 if (!verify_refname_available_dir(
2085 refname, extras, skip,
2086 get_loose_refs(refs), err))
7bd9bcf3 2087 strbuf_addf(err, "there are still refs under '%s'",
7a418f3a 2088 refname);
7bd9bcf3
MH
2089 goto error_return;
2090 }
7a418f3a
MH
2091 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2092 lock->old_oid.hash, type);
7bd9bcf3 2093 }
7a418f3a 2094 if (!resolved) {
7bd9bcf3
MH
2095 last_errno = errno;
2096 if (last_errno != ENOTDIR ||
00eebe35
MH
2097 !verify_refname_available_dir(
2098 refname, extras, skip,
2099 get_loose_refs(refs), err))
0568c8e9 2100 strbuf_addf(err, "unable to resolve reference '%s': %s",
7a418f3a 2101 refname, strerror(last_errno));
7bd9bcf3
MH
2102
2103 goto error_return;
2104 }
2859dcd4 2105
7bd9bcf3
MH
2106 /*
2107 * If the ref did not exist and we are creating it, make sure
2108 * there is no existing packed ref whose name begins with our
2109 * refname, nor a packed ref whose name is a proper prefix of
2110 * our refname.
2111 */
2112 if (is_null_oid(&lock->old_oid) &&
2113 verify_refname_available_dir(refname, extras, skip,
00eebe35
MH
2114 get_packed_refs(refs),
2115 err)) {
7bd9bcf3
MH
2116 last_errno = ENOTDIR;
2117 goto error_return;
2118 }
2119
2120 lock->lk = xcalloc(1, sizeof(struct lock_file));
2121
7bd9bcf3 2122 lock->ref_name = xstrdup(refname);
7bd9bcf3 2123
3b5d3c98 2124 if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
7bd9bcf3 2125 last_errno = errno;
3b5d3c98 2126 unable_to_lock_message(ref_file.buf, errno, err);
7bd9bcf3
MH
2127 goto error_return;
2128 }
2129
6294dcb4 2130 if (verify_lock(lock, old_sha1, mustexist, err)) {
7bd9bcf3
MH
2131 last_errno = errno;
2132 goto error_return;
2133 }
2134 goto out;
2135
2136 error_return:
2137 unlock_ref(lock);
2138 lock = NULL;
2139
2140 out:
2141 strbuf_release(&ref_file);
7bd9bcf3
MH
2142 errno = last_errno;
2143 return lock;
2144}
2145
2146/*
2147 * Write an entry to the packed-refs file for the specified refname.
2148 * If peeled is non-NULL, write it as the entry's peeled value.
2149 */
2150static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2151 unsigned char *peeled)
2152{
2153 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2154 if (peeled)
2155 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2156}
2157
2158/*
2159 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2160 */
2161static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2162{
2163 enum peel_status peel_status = peel_entry(entry, 0);
2164
2165 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2166 error("internal error: %s is not a valid packed reference!",
2167 entry->name);
2168 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2169 peel_status == PEEL_PEELED ?
2170 entry->u.value.peeled.hash : NULL);
2171 return 0;
2172}
2173
2174/*
2175 * Lock the packed-refs file for writing. Flags is passed to
2176 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2177 * errno appropriately and return a nonzero value.
2178 */
49c0df6a 2179static int lock_packed_refs(struct files_ref_store *refs, int flags)
7bd9bcf3
MH
2180{
2181 static int timeout_configured = 0;
2182 static int timeout_value = 1000;
7bd9bcf3
MH
2183 struct packed_ref_cache *packed_ref_cache;
2184
32c597e7 2185 files_assert_main_repository(refs, "lock_packed_refs");
49c0df6a 2186
7bd9bcf3
MH
2187 if (!timeout_configured) {
2188 git_config_get_int("core.packedrefstimeout", &timeout_value);
2189 timeout_configured = 1;
2190 }
2191
2192 if (hold_lock_file_for_update_timeout(
33dfb9f3 2193 &packlock, files_packed_refs_path(refs),
7bd9bcf3
MH
2194 flags, timeout_value) < 0)
2195 return -1;
2196 /*
2197 * Get the current packed-refs while holding the lock. If the
2198 * packed-refs file has been modified since we last read it,
2199 * this will automatically invalidate the cache and re-read
2200 * the packed-refs file.
2201 */
00eebe35 2202 packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
2203 packed_ref_cache->lock = &packlock;
2204 /* Increment the reference count to prevent it from being freed: */
2205 acquire_packed_ref_cache(packed_ref_cache);
2206 return 0;
2207}
2208
2209/*
2210 * Write the current version of the packed refs cache from memory to
2211 * disk. The packed-refs file must already be locked for writing (see
2212 * lock_packed_refs()). Return zero on success. On errors, set errno
2213 * and return a nonzero value
2214 */
49c0df6a 2215static int commit_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2216{
2217 struct packed_ref_cache *packed_ref_cache =
00eebe35 2218 get_packed_ref_cache(refs);
7bd9bcf3
MH
2219 int error = 0;
2220 int save_errno = 0;
2221 FILE *out;
2222
32c597e7 2223 files_assert_main_repository(refs, "commit_packed_refs");
49c0df6a 2224
7bd9bcf3
MH
2225 if (!packed_ref_cache->lock)
2226 die("internal error: packed-refs not locked");
2227
2228 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2229 if (!out)
2230 die_errno("unable to fdopen packed-refs descriptor");
2231
2232 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2233 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2234 0, write_packed_entry_fn, out);
2235
2236 if (commit_lock_file(packed_ref_cache->lock)) {
2237 save_errno = errno;
2238 error = -1;
2239 }
2240 packed_ref_cache->lock = NULL;
2241 release_packed_ref_cache(packed_ref_cache);
2242 errno = save_errno;
2243 return error;
2244}
2245
2246/*
2247 * Rollback the lockfile for the packed-refs file, and discard the
2248 * in-memory packed reference cache. (The packed-refs file will be
2249 * read anew if it is needed again after this function is called.)
2250 */
49c0df6a 2251static void rollback_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2252{
2253 struct packed_ref_cache *packed_ref_cache =
00eebe35 2254 get_packed_ref_cache(refs);
7bd9bcf3 2255
32c597e7 2256 files_assert_main_repository(refs, "rollback_packed_refs");
7bd9bcf3
MH
2257
2258 if (!packed_ref_cache->lock)
2259 die("internal error: packed-refs not locked");
2260 rollback_lock_file(packed_ref_cache->lock);
2261 packed_ref_cache->lock = NULL;
2262 release_packed_ref_cache(packed_ref_cache);
00eebe35 2263 clear_packed_ref_cache(refs);
7bd9bcf3
MH
2264}
2265
2266struct ref_to_prune {
2267 struct ref_to_prune *next;
2268 unsigned char sha1[20];
2269 char name[FLEX_ARRAY];
2270};
2271
2272struct pack_refs_cb_data {
2273 unsigned int flags;
2274 struct ref_dir *packed_refs;
2275 struct ref_to_prune *ref_to_prune;
2276};
2277
2278/*
2279 * An each_ref_entry_fn that is run over loose references only. If
2280 * the loose reference can be packed, add an entry in the packed ref
2281 * cache. If the reference should be pruned, also add it to
2282 * ref_to_prune in the pack_refs_cb_data.
2283 */
2284static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2285{
2286 struct pack_refs_cb_data *cb = cb_data;
2287 enum peel_status peel_status;
2288 struct ref_entry *packed_entry;
2289 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2290
2291 /* Do not pack per-worktree refs: */
2292 if (ref_type(entry->name) != REF_TYPE_NORMAL)
2293 return 0;
2294
2295 /* ALWAYS pack tags */
2296 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2297 return 0;
2298
2299 /* Do not pack symbolic or broken refs: */
ffeef642 2300 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))
7bd9bcf3
MH
2301 return 0;
2302
2303 /* Add a packed ref cache entry equivalent to the loose entry. */
2304 peel_status = peel_entry(entry, 1);
2305 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2306 die("internal error peeling reference %s (%s)",
2307 entry->name, oid_to_hex(&entry->u.value.oid));
2308 packed_entry = find_ref(cb->packed_refs, entry->name);
2309 if (packed_entry) {
2310 /* Overwrite existing packed entry with info from loose entry */
2311 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2312 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2313 } else {
2314 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2315 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2316 add_ref(cb->packed_refs, packed_entry);
2317 }
2318 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2319
2320 /* Schedule the loose reference for pruning if requested. */
2321 if ((cb->flags & PACK_REFS_PRUNE)) {
96ffc06f
JK
2322 struct ref_to_prune *n;
2323 FLEX_ALLOC_STR(n, name, entry->name);
7bd9bcf3 2324 hashcpy(n->sha1, entry->u.value.oid.hash);
7bd9bcf3
MH
2325 n->next = cb->ref_to_prune;
2326 cb->ref_to_prune = n;
2327 }
2328 return 0;
2329}
2330
a8f0db2d
MH
2331enum {
2332 REMOVE_EMPTY_PARENTS_REF = 0x01,
2333 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
2334};
2335
7bd9bcf3 2336/*
a8f0db2d
MH
2337 * Remove empty parent directories associated with the specified
2338 * reference and/or its reflog, but spare [logs/]refs/ and immediate
2339 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
2340 * REMOVE_EMPTY_PARENTS_REFLOG.
7bd9bcf3 2341 */
802de3da
NTND
2342static void try_remove_empty_parents(struct files_ref_store *refs,
2343 const char *refname,
2344 unsigned int flags)
7bd9bcf3 2345{
8bdaecb4 2346 struct strbuf buf = STRBUF_INIT;
e9dcc305 2347 struct strbuf sb = STRBUF_INIT;
7bd9bcf3
MH
2348 char *p, *q;
2349 int i;
8bdaecb4
MH
2350
2351 strbuf_addstr(&buf, refname);
2352 p = buf.buf;
7bd9bcf3
MH
2353 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2354 while (*p && *p != '/')
2355 p++;
2356 /* tolerate duplicate slashes; see check_refname_format() */
2357 while (*p == '/')
2358 p++;
2359 }
8bdaecb4 2360 q = buf.buf + buf.len;
a8f0db2d 2361 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
7bd9bcf3
MH
2362 while (q > p && *q != '/')
2363 q--;
2364 while (q > p && *(q-1) == '/')
2365 q--;
2366 if (q == p)
2367 break;
8bdaecb4 2368 strbuf_setlen(&buf, q - buf.buf);
e9dcc305
NTND
2369
2370 strbuf_reset(&sb);
19e02f4f 2371 files_ref_path(refs, &sb, buf.buf);
e9dcc305 2372 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
a8f0db2d 2373 flags &= ~REMOVE_EMPTY_PARENTS_REF;
e9dcc305
NTND
2374
2375 strbuf_reset(&sb);
802de3da 2376 files_reflog_path(refs, &sb, buf.buf);
e9dcc305 2377 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
a8f0db2d 2378 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
7bd9bcf3 2379 }
8bdaecb4 2380 strbuf_release(&buf);
e9dcc305 2381 strbuf_release(&sb);
7bd9bcf3
MH
2382}
2383
2384/* make sure nobody touched the ref, and unlink */
2385static void prune_ref(struct ref_to_prune *r)
2386{
2387 struct ref_transaction *transaction;
2388 struct strbuf err = STRBUF_INIT;
2389
2390 if (check_refname_format(r->name, 0))
2391 return;
2392
2393 transaction = ref_transaction_begin(&err);
2394 if (!transaction ||
2395 ref_transaction_delete(transaction, r->name, r->sha1,
c52ce248 2396 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
7bd9bcf3
MH
2397 ref_transaction_commit(transaction, &err)) {
2398 ref_transaction_free(transaction);
2399 error("%s", err.buf);
2400 strbuf_release(&err);
2401 return;
2402 }
2403 ref_transaction_free(transaction);
2404 strbuf_release(&err);
7bd9bcf3
MH
2405}
2406
2407static void prune_refs(struct ref_to_prune *r)
2408{
2409 while (r) {
2410 prune_ref(r);
2411 r = r->next;
2412 }
2413}
2414
8231527e 2415static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
7bd9bcf3 2416{
00eebe35 2417 struct files_ref_store *refs =
8231527e 2418 files_downcast(ref_store, 0, "pack_refs");
7bd9bcf3
MH
2419 struct pack_refs_cb_data cbdata;
2420
2421 memset(&cbdata, 0, sizeof(cbdata));
2422 cbdata.flags = flags;
2423
49c0df6a 2424 lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
00eebe35 2425 cbdata.packed_refs = get_packed_refs(refs);
7bd9bcf3 2426
00eebe35 2427 do_for_each_entry_in_dir(get_loose_refs(refs), 0,
7bd9bcf3
MH
2428 pack_if_possible_fn, &cbdata);
2429
49c0df6a 2430 if (commit_packed_refs(refs))
7bd9bcf3
MH
2431 die_errno("unable to overwrite old ref-pack file");
2432
2433 prune_refs(cbdata.ref_to_prune);
2434 return 0;
2435}
2436
2437/*
2438 * Rewrite the packed-refs file, omitting any refs listed in
2439 * 'refnames'. On error, leave packed-refs unchanged, write an error
2440 * message to 'err', and return a nonzero value.
2441 *
2442 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2443 */
0a95ac5f
MH
2444static int repack_without_refs(struct files_ref_store *refs,
2445 struct string_list *refnames, struct strbuf *err)
7bd9bcf3
MH
2446{
2447 struct ref_dir *packed;
2448 struct string_list_item *refname;
2449 int ret, needs_repacking = 0, removed = 0;
2450
32c597e7 2451 files_assert_main_repository(refs, "repack_without_refs");
7bd9bcf3
MH
2452 assert(err);
2453
2454 /* Look for a packed ref */
2455 for_each_string_list_item(refname, refnames) {
f0d21efc 2456 if (get_packed_ref(refs, refname->string)) {
7bd9bcf3
MH
2457 needs_repacking = 1;
2458 break;
2459 }
2460 }
2461
2462 /* Avoid locking if we have nothing to do */
2463 if (!needs_repacking)
2464 return 0; /* no refname exists in packed refs */
2465
49c0df6a 2466 if (lock_packed_refs(refs, 0)) {
33dfb9f3 2467 unable_to_lock_message(files_packed_refs_path(refs), errno, err);
7bd9bcf3
MH
2468 return -1;
2469 }
00eebe35 2470 packed = get_packed_refs(refs);
7bd9bcf3
MH
2471
2472 /* Remove refnames from the cache */
2473 for_each_string_list_item(refname, refnames)
2474 if (remove_entry(packed, refname->string) != -1)
2475 removed = 1;
2476 if (!removed) {
2477 /*
2478 * All packed entries disappeared while we were
2479 * acquiring the lock.
2480 */
49c0df6a 2481 rollback_packed_refs(refs);
7bd9bcf3
MH
2482 return 0;
2483 }
2484
2485 /* Write what remains */
49c0df6a 2486 ret = commit_packed_refs(refs);
7bd9bcf3
MH
2487 if (ret)
2488 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2489 strerror(errno));
2490 return ret;
2491}
2492
a27dcf89
DT
2493static int files_delete_refs(struct ref_store *ref_store,
2494 struct string_list *refnames, unsigned int flags)
7bd9bcf3 2495{
0a95ac5f 2496 struct files_ref_store *refs =
a27dcf89 2497 files_downcast(ref_store, 0, "delete_refs");
7bd9bcf3
MH
2498 struct strbuf err = STRBUF_INIT;
2499 int i, result = 0;
2500
2501 if (!refnames->nr)
2502 return 0;
2503
0a95ac5f 2504 result = repack_without_refs(refs, refnames, &err);
7bd9bcf3
MH
2505 if (result) {
2506 /*
2507 * If we failed to rewrite the packed-refs file, then
2508 * it is unsafe to try to remove loose refs, because
2509 * doing so might expose an obsolete packed value for
2510 * a reference that might even point at an object that
2511 * has been garbage collected.
2512 */
2513 if (refnames->nr == 1)
2514 error(_("could not delete reference %s: %s"),
2515 refnames->items[0].string, err.buf);
2516 else
2517 error(_("could not delete references: %s"), err.buf);
2518
2519 goto out;
2520 }
2521
2522 for (i = 0; i < refnames->nr; i++) {
2523 const char *refname = refnames->items[i].string;
2524
755b49ae 2525 if (delete_ref(NULL, refname, NULL, flags))
7bd9bcf3
MH
2526 result |= error(_("could not remove reference %s"), refname);
2527 }
2528
2529out:
2530 strbuf_release(&err);
2531 return result;
2532}
2533
2534/*
2535 * People using contrib's git-new-workdir have .git/logs/refs ->
2536 * /some/other/path/.git/logs/refs, and that may live on another device.
2537 *
2538 * IOW, to avoid cross device rename errors, the temporary renamed log must
2539 * live into logs/refs.
2540 */
a5c1efd6 2541#define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
7bd9bcf3 2542
e9dcc305
NTND
2543struct rename_cb {
2544 const char *tmp_renamed_log;
2545 int true_errno;
2546};
2547
2548static int rename_tmp_log_callback(const char *path, void *cb_data)
7bd9bcf3 2549{
e9dcc305 2550 struct rename_cb *cb = cb_data;
7bd9bcf3 2551
e9dcc305 2552 if (rename(cb->tmp_renamed_log, path)) {
6a7f3631
MH
2553 /*
2554 * rename(a, b) when b is an existing directory ought
2555 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
2556 * Sheesh. Record the true errno for error reporting,
2557 * but report EISDIR to raceproof_create_file() so
2558 * that it knows to retry.
2559 */
e9dcc305 2560 cb->true_errno = errno;
6a7f3631
MH
2561 if (errno == ENOTDIR)
2562 errno = EISDIR;
2563 return -1;
2564 } else {
2565 return 0;
7bd9bcf3 2566 }
6a7f3631 2567}
7bd9bcf3 2568
802de3da 2569static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
6a7f3631 2570{
e9dcc305
NTND
2571 struct strbuf path = STRBUF_INIT;
2572 struct strbuf tmp = STRBUF_INIT;
2573 struct rename_cb cb;
2574 int ret;
6a7f3631 2575
802de3da
NTND
2576 files_reflog_path(refs, &path, newrefname);
2577 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
e9dcc305
NTND
2578 cb.tmp_renamed_log = tmp.buf;
2579 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
6a7f3631
MH
2580 if (ret) {
2581 if (errno == EISDIR)
e9dcc305 2582 error("directory not empty: %s", path.buf);
6a7f3631 2583 else
990c98d2 2584 error("unable to move logfile %s to %s: %s",
e9dcc305
NTND
2585 tmp.buf, path.buf,
2586 strerror(cb.true_errno));
7bd9bcf3 2587 }
6a7f3631 2588
e9dcc305
NTND
2589 strbuf_release(&path);
2590 strbuf_release(&tmp);
7bd9bcf3
MH
2591 return ret;
2592}
2593
62665823
MH
2594static int files_verify_refname_available(struct ref_store *ref_store,
2595 const char *newname,
2596 const struct string_list *extras,
2597 const struct string_list *skip,
2598 struct strbuf *err)
7bd9bcf3 2599{
00eebe35 2600 struct files_ref_store *refs =
62665823 2601 files_downcast(ref_store, 1, "verify_refname_available");
00eebe35
MH
2602 struct ref_dir *packed_refs = get_packed_refs(refs);
2603 struct ref_dir *loose_refs = get_loose_refs(refs);
7bd9bcf3
MH
2604
2605 if (verify_refname_available_dir(newname, extras, skip,
2606 packed_refs, err) ||
2607 verify_refname_available_dir(newname, extras, skip,
2608 loose_refs, err))
2609 return -1;
2610
2611 return 0;
2612}
2613
7bd9bcf3
MH
2614static int write_ref_to_lockfile(struct ref_lock *lock,
2615 const unsigned char *sha1, struct strbuf *err);
f18a7892
MH
2616static int commit_ref_update(struct files_ref_store *refs,
2617 struct ref_lock *lock,
7bd9bcf3 2618 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2619 struct strbuf *err);
7bd9bcf3 2620
9b6b40d9
DT
2621static int files_rename_ref(struct ref_store *ref_store,
2622 const char *oldrefname, const char *newrefname,
2623 const char *logmsg)
7bd9bcf3 2624{
9b6b40d9
DT
2625 struct files_ref_store *refs =
2626 files_downcast(ref_store, 0, "rename_ref");
7bd9bcf3
MH
2627 unsigned char sha1[20], orig_sha1[20];
2628 int flag = 0, logmoved = 0;
2629 struct ref_lock *lock;
2630 struct stat loginfo;
e9dcc305
NTND
2631 struct strbuf sb_oldref = STRBUF_INIT;
2632 struct strbuf sb_newref = STRBUF_INIT;
2633 struct strbuf tmp_renamed_log = STRBUF_INIT;
2634 int log, ret;
7bd9bcf3
MH
2635 struct strbuf err = STRBUF_INIT;
2636
802de3da
NTND
2637 files_reflog_path(refs, &sb_oldref, oldrefname);
2638 files_reflog_path(refs, &sb_newref, newrefname);
2639 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
e9dcc305
NTND
2640
2641 log = !lstat(sb_oldref.buf, &loginfo);
0a3f07d6
NTND
2642 if (log && S_ISLNK(loginfo.st_mode)) {
2643 ret = error("reflog for %s is a symlink", oldrefname);
2644 goto out;
2645 }
7bd9bcf3 2646
12fd3496 2647 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
0a3f07d6
NTND
2648 orig_sha1, &flag)) {
2649 ret = error("refname %s not found", oldrefname);
2650 goto out;
2651 }
e711b1af 2652
0a3f07d6
NTND
2653 if (flag & REF_ISSYMREF) {
2654 ret = error("refname %s is a symbolic ref, renaming it is not supported",
2655 oldrefname);
2656 goto out;
2657 }
2658 if (!rename_ref_available(oldrefname, newrefname)) {
2659 ret = 1;
2660 goto out;
2661 }
7bd9bcf3 2662
e9dcc305 2663 if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
a5c1efd6 2664 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
0a3f07d6
NTND
2665 oldrefname, strerror(errno));
2666 goto out;
2667 }
7bd9bcf3 2668
893dbf5b 2669 if (delete_ref(logmsg, oldrefname, orig_sha1, REF_NODEREF)) {
7bd9bcf3
MH
2670 error("unable to delete old %s", oldrefname);
2671 goto rollback;
2672 }
2673
12fd3496
DT
2674 /*
2675 * Since we are doing a shallow lookup, sha1 is not the
2676 * correct value to pass to delete_ref as old_sha1. But that
2677 * doesn't matter, because an old_sha1 check wouldn't add to
2678 * the safety anyway; we want to delete the reference whatever
2679 * its current value.
2680 */
2681 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2682 sha1, NULL) &&
755b49ae 2683 delete_ref(NULL, newrefname, NULL, REF_NODEREF)) {
58364324 2684 if (errno == EISDIR) {
7bd9bcf3
MH
2685 struct strbuf path = STRBUF_INIT;
2686 int result;
2687
19e02f4f 2688 files_ref_path(refs, &path, newrefname);
7bd9bcf3
MH
2689 result = remove_empty_directories(&path);
2690 strbuf_release(&path);
2691
2692 if (result) {
2693 error("Directory not empty: %s", newrefname);
2694 goto rollback;
2695 }
2696 } else {
2697 error("unable to delete existing %s", newrefname);
2698 goto rollback;
2699 }
2700 }
2701
802de3da 2702 if (log && rename_tmp_log(refs, newrefname))
7bd9bcf3
MH
2703 goto rollback;
2704
2705 logmoved = log;
2706
7eb27cdf
MH
2707 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
2708 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
2709 if (!lock) {
2710 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2711 strbuf_release(&err);
2712 goto rollback;
2713 }
2714 hashcpy(lock->old_oid.hash, orig_sha1);
2715
2716 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 2717 commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {
7bd9bcf3
MH
2718 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
2719 strbuf_release(&err);
2720 goto rollback;
2721 }
2722
0a3f07d6
NTND
2723 ret = 0;
2724 goto out;
7bd9bcf3
MH
2725
2726 rollback:
7eb27cdf
MH
2727 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
2728 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
2729 if (!lock) {
2730 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2731 strbuf_release(&err);
2732 goto rollbacklog;
2733 }
2734
2735 flag = log_all_ref_updates;
341fb286 2736 log_all_ref_updates = LOG_REFS_NONE;
7bd9bcf3 2737 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 2738 commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {
7bd9bcf3
MH
2739 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
2740 strbuf_release(&err);
2741 }
2742 log_all_ref_updates = flag;
2743
2744 rollbacklog:
e9dcc305 2745 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
7bd9bcf3
MH
2746 error("unable to restore logfile %s from %s: %s",
2747 oldrefname, newrefname, strerror(errno));
2748 if (!logmoved && log &&
e9dcc305 2749 rename(tmp_renamed_log.buf, sb_oldref.buf))
a5c1efd6 2750 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
7bd9bcf3 2751 oldrefname, strerror(errno));
0a3f07d6
NTND
2752 ret = 1;
2753 out:
e9dcc305
NTND
2754 strbuf_release(&sb_newref);
2755 strbuf_release(&sb_oldref);
2756 strbuf_release(&tmp_renamed_log);
2757
0a3f07d6 2758 return ret;
7bd9bcf3
MH
2759}
2760
2761static int close_ref(struct ref_lock *lock)
2762{
2763 if (close_lock_file(lock->lk))
2764 return -1;
2765 return 0;
2766}
2767
2768static int commit_ref(struct ref_lock *lock)
2769{
5387c0d8
MH
2770 char *path = get_locked_file_path(lock->lk);
2771 struct stat st;
2772
2773 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
2774 /*
2775 * There is a directory at the path we want to rename
2776 * the lockfile to. Hopefully it is empty; try to
2777 * delete it.
2778 */
2779 size_t len = strlen(path);
2780 struct strbuf sb_path = STRBUF_INIT;
2781
2782 strbuf_attach(&sb_path, path, len, len);
2783
2784 /*
2785 * If this fails, commit_lock_file() will also fail
2786 * and will report the problem.
2787 */
2788 remove_empty_directories(&sb_path);
2789 strbuf_release(&sb_path);
2790 } else {
2791 free(path);
2792 }
2793
7bd9bcf3
MH
2794 if (commit_lock_file(lock->lk))
2795 return -1;
2796 return 0;
2797}
2798
1fb0c809
MH
2799static int open_or_create_logfile(const char *path, void *cb)
2800{
2801 int *fd = cb;
2802
2803 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
2804 return (*fd < 0) ? -1 : 0;
2805}
2806
7bd9bcf3 2807/*
4533e534
MH
2808 * Create a reflog for a ref. If force_create = 0, only create the
2809 * reflog for certain refs (those for which should_autocreate_reflog
2810 * returns non-zero). Otherwise, create it regardless of the reference
2811 * name. If the logfile already existed or was created, return 0 and
2812 * set *logfd to the file descriptor opened for appending to the file.
2813 * If no logfile exists and we decided not to create one, return 0 and
2814 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
2815 * return -1.
7bd9bcf3 2816 */
802de3da
NTND
2817static int log_ref_setup(struct files_ref_store *refs,
2818 const char *refname, int force_create,
4533e534 2819 int *logfd, struct strbuf *err)
7bd9bcf3 2820{
802de3da
NTND
2821 struct strbuf logfile_sb = STRBUF_INIT;
2822 char *logfile;
2823
2824 files_reflog_path(refs, &logfile_sb, refname);
2825 logfile = strbuf_detach(&logfile_sb, NULL);
7bd9bcf3 2826
7bd9bcf3 2827 if (force_create || should_autocreate_reflog(refname)) {
4533e534 2828 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1fb0c809
MH
2829 if (errno == ENOENT)
2830 strbuf_addf(err, "unable to create directory for '%s': "
4533e534 2831 "%s", logfile, strerror(errno));
1fb0c809
MH
2832 else if (errno == EISDIR)
2833 strbuf_addf(err, "there are still logs under '%s'",
4533e534 2834 logfile);
1fb0c809 2835 else
854bda6b 2836 strbuf_addf(err, "unable to append to '%s': %s",
4533e534 2837 logfile, strerror(errno));
7bd9bcf3 2838
4533e534 2839 goto error;
7bd9bcf3 2840 }
854bda6b 2841 } else {
4533e534 2842 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
e404f459 2843 if (*logfd < 0) {
854bda6b
MH
2844 if (errno == ENOENT || errno == EISDIR) {
2845 /*
2846 * The logfile doesn't already exist,
2847 * but that is not an error; it only
2848 * means that we won't write log
2849 * entries to it.
2850 */
2851 ;
2852 } else {
2853 strbuf_addf(err, "unable to append to '%s': %s",
4533e534
MH
2854 logfile, strerror(errno));
2855 goto error;
854bda6b 2856 }
7bd9bcf3
MH
2857 }
2858 }
2859
e404f459 2860 if (*logfd >= 0)
4533e534 2861 adjust_shared_perm(logfile);
854bda6b 2862
4533e534 2863 free(logfile);
7bd9bcf3 2864 return 0;
7bd9bcf3 2865
4533e534
MH
2866error:
2867 free(logfile);
2868 return -1;
7bd9bcf3 2869}
7bd9bcf3 2870
e3688bd6
DT
2871static int files_create_reflog(struct ref_store *ref_store,
2872 const char *refname, int force_create,
2873 struct strbuf *err)
7bd9bcf3 2874{
802de3da
NTND
2875 struct files_ref_store *refs =
2876 files_downcast(ref_store, 0, "create_reflog");
e404f459 2877 int fd;
7bd9bcf3 2878
802de3da 2879 if (log_ref_setup(refs, refname, force_create, &fd, err))
4533e534
MH
2880 return -1;
2881
e404f459
MH
2882 if (fd >= 0)
2883 close(fd);
4533e534
MH
2884
2885 return 0;
7bd9bcf3
MH
2886}
2887
2888static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2889 const unsigned char *new_sha1,
2890 const char *committer, const char *msg)
2891{
2892 int msglen, written;
2893 unsigned maxlen, len;
2894 char *logrec;
2895
2896 msglen = msg ? strlen(msg) : 0;
2897 maxlen = strlen(committer) + msglen + 100;
2898 logrec = xmalloc(maxlen);
2899 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2900 sha1_to_hex(old_sha1),
2901 sha1_to_hex(new_sha1),
2902 committer);
2903 if (msglen)
2904 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2905
2906 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2907 free(logrec);
2908 if (written != len)
2909 return -1;
2910
2911 return 0;
2912}
2913
802de3da
NTND
2914static int files_log_ref_write(struct files_ref_store *refs,
2915 const char *refname, const unsigned char *old_sha1,
11f8457f
NTND
2916 const unsigned char *new_sha1, const char *msg,
2917 int flags, struct strbuf *err)
7bd9bcf3 2918{
e404f459 2919 int logfd, result;
7bd9bcf3 2920
341fb286
CW
2921 if (log_all_ref_updates == LOG_REFS_UNSET)
2922 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
7bd9bcf3 2923
802de3da
NTND
2924 result = log_ref_setup(refs, refname,
2925 flags & REF_FORCE_CREATE_REFLOG,
4533e534 2926 &logfd, err);
7bd9bcf3
MH
2927
2928 if (result)
2929 return result;
2930
7bd9bcf3
MH
2931 if (logfd < 0)
2932 return 0;
2933 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2934 git_committer_info(0), msg);
2935 if (result) {
e9dcc305 2936 struct strbuf sb = STRBUF_INIT;
87b21e05
MH
2937 int save_errno = errno;
2938
802de3da 2939 files_reflog_path(refs, &sb, refname);
87b21e05 2940 strbuf_addf(err, "unable to append to '%s': %s",
e9dcc305
NTND
2941 sb.buf, strerror(save_errno));
2942 strbuf_release(&sb);
7bd9bcf3
MH
2943 close(logfd);
2944 return -1;
2945 }
2946 if (close(logfd)) {
e9dcc305 2947 struct strbuf sb = STRBUF_INIT;
87b21e05
MH
2948 int save_errno = errno;
2949
802de3da 2950 files_reflog_path(refs, &sb, refname);
87b21e05 2951 strbuf_addf(err, "unable to append to '%s': %s",
e9dcc305
NTND
2952 sb.buf, strerror(save_errno));
2953 strbuf_release(&sb);
7bd9bcf3
MH
2954 return -1;
2955 }
2956 return 0;
2957}
2958
7bd9bcf3
MH
2959/*
2960 * Write sha1 into the open lockfile, then close the lockfile. On
2961 * errors, rollback the lockfile, fill in *err and
2962 * return -1.
2963 */
2964static int write_ref_to_lockfile(struct ref_lock *lock,
2965 const unsigned char *sha1, struct strbuf *err)
2966{
2967 static char term = '\n';
2968 struct object *o;
2969 int fd;
2970
2971 o = parse_object(sha1);
2972 if (!o) {
2973 strbuf_addf(err,
0568c8e9 2974 "trying to write ref '%s' with nonexistent object %s",
7bd9bcf3
MH
2975 lock->ref_name, sha1_to_hex(sha1));
2976 unlock_ref(lock);
2977 return -1;
2978 }
2979 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2980 strbuf_addf(err,
0568c8e9 2981 "trying to write non-commit object %s to branch '%s'",
7bd9bcf3
MH
2982 sha1_to_hex(sha1), lock->ref_name);
2983 unlock_ref(lock);
2984 return -1;
2985 }
2986 fd = get_lock_file_fd(lock->lk);
2987 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
2988 write_in_full(fd, &term, 1) != 1 ||
2989 close_ref(lock) < 0) {
2990 strbuf_addf(err,
0568c8e9 2991 "couldn't write '%s'", get_lock_file_path(lock->lk));
7bd9bcf3
MH
2992 unlock_ref(lock);
2993 return -1;
2994 }
2995 return 0;
2996}
2997
2998/*
2999 * Commit a change to a loose reference that has already been written
3000 * to the loose reference lockfile. Also update the reflogs if
3001 * necessary, using the specified lockmsg (which can be NULL).
3002 */
f18a7892
MH
3003static int commit_ref_update(struct files_ref_store *refs,
3004 struct ref_lock *lock,
7bd9bcf3 3005 const unsigned char *sha1, const char *logmsg,
5d9b2de4 3006 struct strbuf *err)
7bd9bcf3 3007{
32c597e7 3008 files_assert_main_repository(refs, "commit_ref_update");
00eebe35
MH
3009
3010 clear_loose_ref_cache(refs);
802de3da
NTND
3011 if (files_log_ref_write(refs, lock->ref_name,
3012 lock->old_oid.hash, sha1,
81b1b6d4 3013 logmsg, 0, err)) {
7bd9bcf3 3014 char *old_msg = strbuf_detach(err, NULL);
0568c8e9 3015 strbuf_addf(err, "cannot update the ref '%s': %s",
7bd9bcf3
MH
3016 lock->ref_name, old_msg);
3017 free(old_msg);
3018 unlock_ref(lock);
3019 return -1;
3020 }
7a418f3a
MH
3021
3022 if (strcmp(lock->ref_name, "HEAD") != 0) {
7bd9bcf3
MH
3023 /*
3024 * Special hack: If a branch is updated directly and HEAD
3025 * points to it (may happen on the remote side of a push
3026 * for example) then logically the HEAD reflog should be
3027 * updated too.
3028 * A generic solution implies reverse symref information,
3029 * but finding all symrefs pointing to the given branch
3030 * would be rather costly for this rare event (the direct
3031 * update of a branch) to be worth it. So let's cheat and
3032 * check with HEAD only which should cover 99% of all usage
3033 * scenarios (even 100% of the default ones).
3034 */
3035 unsigned char head_sha1[20];
3036 int head_flag;
3037 const char *head_ref;
7a418f3a 3038
7bd9bcf3
MH
3039 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3040 head_sha1, &head_flag);
3041 if (head_ref && (head_flag & REF_ISSYMREF) &&
3042 !strcmp(head_ref, lock->ref_name)) {
3043 struct strbuf log_err = STRBUF_INIT;
802de3da
NTND
3044 if (files_log_ref_write(refs, "HEAD",
3045 lock->old_oid.hash, sha1,
3046 logmsg, 0, &log_err)) {
7bd9bcf3
MH
3047 error("%s", log_err.buf);
3048 strbuf_release(&log_err);
3049 }
3050 }
3051 }
7a418f3a 3052
7bd9bcf3 3053 if (commit_ref(lock)) {
0568c8e9 3054 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
7bd9bcf3
MH
3055 unlock_ref(lock);
3056 return -1;
3057 }
3058
3059 unlock_ref(lock);
3060 return 0;
3061}
3062
370e5ad6 3063static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 3064{
370e5ad6 3065 int ret = -1;
7bd9bcf3 3066#ifndef NO_SYMLINK_HEAD
370e5ad6
JK
3067 char *ref_path = get_locked_file_path(lock->lk);
3068 unlink(ref_path);
3069 ret = symlink(target, ref_path);
3070 free(ref_path);
3071
3072 if (ret)
7bd9bcf3 3073 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 3074#endif
370e5ad6
JK
3075 return ret;
3076}
7bd9bcf3 3077
802de3da
NTND
3078static void update_symref_reflog(struct files_ref_store *refs,
3079 struct ref_lock *lock, const char *refname,
370e5ad6
JK
3080 const char *target, const char *logmsg)
3081{
3082 struct strbuf err = STRBUF_INIT;
3083 unsigned char new_sha1[20];
b9badadd 3084 if (logmsg && !read_ref(target, new_sha1) &&
802de3da
NTND
3085 files_log_ref_write(refs, refname, lock->old_oid.hash,
3086 new_sha1, logmsg, 0, &err)) {
7bd9bcf3
MH
3087 error("%s", err.buf);
3088 strbuf_release(&err);
3089 }
370e5ad6 3090}
7bd9bcf3 3091
802de3da
NTND
3092static int create_symref_locked(struct files_ref_store *refs,
3093 struct ref_lock *lock, const char *refname,
370e5ad6
JK
3094 const char *target, const char *logmsg)
3095{
3096 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
802de3da 3097 update_symref_reflog(refs, lock, refname, target, logmsg);
370e5ad6
JK
3098 return 0;
3099 }
3100
3101 if (!fdopen_lock_file(lock->lk, "w"))
3102 return error("unable to fdopen %s: %s",
3103 lock->lk->tempfile.filename.buf, strerror(errno));
3104
802de3da 3105 update_symref_reflog(refs, lock, refname, target, logmsg);
396da8f7 3106
370e5ad6
JK
3107 /* no error check; commit_ref will check ferror */
3108 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
3109 if (commit_ref(lock) < 0)
3110 return error("unable to write symref for %s: %s", refname,
3111 strerror(errno));
7bd9bcf3
MH
3112 return 0;
3113}
3114
284689ba
MH
3115static int files_create_symref(struct ref_store *ref_store,
3116 const char *refname, const char *target,
3117 const char *logmsg)
370e5ad6 3118{
7eb27cdf
MH
3119 struct files_ref_store *refs =
3120 files_downcast(ref_store, 0, "create_symref");
370e5ad6
JK
3121 struct strbuf err = STRBUF_INIT;
3122 struct ref_lock *lock;
3123 int ret;
3124
7eb27cdf
MH
3125 lock = lock_ref_sha1_basic(refs, refname, NULL,
3126 NULL, NULL, REF_NODEREF, NULL,
370e5ad6
JK
3127 &err);
3128 if (!lock) {
3129 error("%s", err.buf);
3130 strbuf_release(&err);
3131 return -1;
3132 }
3133
802de3da 3134 ret = create_symref_locked(refs, lock, refname, target, logmsg);
370e5ad6
JK
3135 unlock_ref(lock);
3136 return ret;
3137}
3138
39ee4c6c 3139int set_worktree_head_symref(const char *gitdir, const char *target, const char *logmsg)
2233066e 3140{
802de3da
NTND
3141 /*
3142 * FIXME: this obviously will not work well for future refs
3143 * backends. This function needs to die.
3144 */
3145 struct files_ref_store *refs =
077be78d 3146 files_downcast(get_main_ref_store(), 0, "set_head_symref");
802de3da 3147
2233066e
KY
3148 static struct lock_file head_lock;
3149 struct ref_lock *lock;
2233066e
KY
3150 struct strbuf head_path = STRBUF_INIT;
3151 const char *head_rel;
3152 int ret;
3153
3154 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));
3155 if (hold_lock_file_for_update(&head_lock, head_path.buf,
3156 LOCK_NO_DEREF) < 0) {
18eb3a9c
KY
3157 struct strbuf err = STRBUF_INIT;
3158 unable_to_lock_message(head_path.buf, errno, &err);
2233066e
KY
3159 error("%s", err.buf);
3160 strbuf_release(&err);
3161 strbuf_release(&head_path);
3162 return -1;
3163 }
3164
3165 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for
3166 linked trees */
3167 head_rel = remove_leading_path(head_path.buf,
3168 absolute_path(get_git_common_dir()));
3169 /* to make use of create_symref_locked(), initialize ref_lock */
3170 lock = xcalloc(1, sizeof(struct ref_lock));
3171 lock->lk = &head_lock;
3172 lock->ref_name = xstrdup(head_rel);
2233066e 3173
802de3da 3174 ret = create_symref_locked(refs, lock, head_rel, target, logmsg);
2233066e
KY
3175
3176 unlock_ref(lock); /* will free lock */
3177 strbuf_release(&head_path);
3178 return ret;
3179}
3180
e3688bd6
DT
3181static int files_reflog_exists(struct ref_store *ref_store,
3182 const char *refname)
7bd9bcf3 3183{
802de3da
NTND
3184 struct files_ref_store *refs =
3185 files_downcast(ref_store, 0, "reflog_exists");
e9dcc305 3186 struct strbuf sb = STRBUF_INIT;
7bd9bcf3 3187 struct stat st;
e9dcc305 3188 int ret;
7bd9bcf3 3189
802de3da 3190 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3191 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
3192 strbuf_release(&sb);
3193 return ret;
7bd9bcf3
MH
3194}
3195
e3688bd6
DT
3196static int files_delete_reflog(struct ref_store *ref_store,
3197 const char *refname)
7bd9bcf3 3198{
802de3da
NTND
3199 struct files_ref_store *refs =
3200 files_downcast(ref_store, 0, "delete_reflog");
e9dcc305
NTND
3201 struct strbuf sb = STRBUF_INIT;
3202 int ret;
3203
802de3da 3204 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3205 ret = remove_path(sb.buf);
3206 strbuf_release(&sb);
3207 return ret;
7bd9bcf3
MH
3208}
3209
3210static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3211{
9461d272 3212 struct object_id ooid, noid;
7bd9bcf3
MH
3213 char *email_end, *message;
3214 unsigned long timestamp;
3215 int tz;
43bc3b6c 3216 const char *p = sb->buf;
7bd9bcf3
MH
3217
3218 /* old SP new SP name <email> SP time TAB msg LF */
43bc3b6c 3219 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
3220 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
3221 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
3222 !(email_end = strchr(p, '>')) ||
7bd9bcf3
MH
3223 email_end[1] != ' ' ||
3224 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3225 !message || message[0] != ' ' ||
3226 (message[1] != '+' && message[1] != '-') ||
3227 !isdigit(message[2]) || !isdigit(message[3]) ||
3228 !isdigit(message[4]) || !isdigit(message[5]))
3229 return 0; /* corrupt? */
3230 email_end[1] = '\0';
3231 tz = strtol(message + 1, NULL, 10);
3232 if (message[6] != '\t')
3233 message += 6;
3234 else
3235 message += 7;
43bc3b6c 3236 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
7bd9bcf3
MH
3237}
3238
3239static char *find_beginning_of_line(char *bob, char *scan)
3240{
3241 while (bob < scan && *(--scan) != '\n')
3242 ; /* keep scanning backwards */
3243 /*
3244 * Return either beginning of the buffer, or LF at the end of
3245 * the previous line.
3246 */
3247 return scan;
3248}
3249
e3688bd6
DT
3250static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
3251 const char *refname,
3252 each_reflog_ent_fn fn,
3253 void *cb_data)
7bd9bcf3 3254{
802de3da
NTND
3255 struct files_ref_store *refs =
3256 files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
7bd9bcf3
MH
3257 struct strbuf sb = STRBUF_INIT;
3258 FILE *logfp;
3259 long pos;
3260 int ret = 0, at_tail = 1;
3261
802de3da 3262 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3263 logfp = fopen(sb.buf, "r");
3264 strbuf_release(&sb);
7bd9bcf3
MH
3265 if (!logfp)
3266 return -1;
3267
3268 /* Jump to the end */
3269 if (fseek(logfp, 0, SEEK_END) < 0)
3270 return error("cannot seek back reflog for %s: %s",
3271 refname, strerror(errno));
3272 pos = ftell(logfp);
3273 while (!ret && 0 < pos) {
3274 int cnt;
3275 size_t nread;
3276 char buf[BUFSIZ];
3277 char *endp, *scanp;
3278
3279 /* Fill next block from the end */
3280 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3281 if (fseek(logfp, pos - cnt, SEEK_SET))
3282 return error("cannot seek back reflog for %s: %s",
3283 refname, strerror(errno));
3284 nread = fread(buf, cnt, 1, logfp);
3285 if (nread != 1)
3286 return error("cannot read %d bytes from reflog for %s: %s",
3287 cnt, refname, strerror(errno));
3288 pos -= cnt;
3289
3290 scanp = endp = buf + cnt;
3291 if (at_tail && scanp[-1] == '\n')
3292 /* Looking at the final LF at the end of the file */
3293 scanp--;
3294 at_tail = 0;
3295
3296 while (buf < scanp) {
3297 /*
3298 * terminating LF of the previous line, or the beginning
3299 * of the buffer.
3300 */
3301 char *bp;
3302
3303 bp = find_beginning_of_line(buf, scanp);
3304
3305 if (*bp == '\n') {
3306 /*
3307 * The newline is the end of the previous line,
3308 * so we know we have complete line starting
3309 * at (bp + 1). Prefix it onto any prior data
3310 * we collected for the line and process it.
3311 */
3312 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3313 scanp = bp;
3314 endp = bp + 1;
3315 ret = show_one_reflog_ent(&sb, fn, cb_data);
3316 strbuf_reset(&sb);
3317 if (ret)
3318 break;
3319 } else if (!pos) {
3320 /*
3321 * We are at the start of the buffer, and the
3322 * start of the file; there is no previous
3323 * line, and we have everything for this one.
3324 * Process it, and we can end the loop.
3325 */
3326 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3327 ret = show_one_reflog_ent(&sb, fn, cb_data);
3328 strbuf_reset(&sb);
3329 break;
3330 }
3331
3332 if (bp == buf) {
3333 /*
3334 * We are at the start of the buffer, and there
3335 * is more file to read backwards. Which means
3336 * we are in the middle of a line. Note that we
3337 * may get here even if *bp was a newline; that
3338 * just means we are at the exact end of the
3339 * previous line, rather than some spot in the
3340 * middle.
3341 *
3342 * Save away what we have to be combined with
3343 * the data from the next read.
3344 */
3345 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3346 break;
3347 }
3348 }
3349
3350 }
3351 if (!ret && sb.len)
3352 die("BUG: reverse reflog parser had leftover data");
3353
3354 fclose(logfp);
3355 strbuf_release(&sb);
3356 return ret;
3357}
3358
e3688bd6
DT
3359static int files_for_each_reflog_ent(struct ref_store *ref_store,
3360 const char *refname,
3361 each_reflog_ent_fn fn, void *cb_data)
7bd9bcf3 3362{
802de3da
NTND
3363 struct files_ref_store *refs =
3364 files_downcast(ref_store, 0, "for_each_reflog_ent");
7bd9bcf3
MH
3365 FILE *logfp;
3366 struct strbuf sb = STRBUF_INIT;
3367 int ret = 0;
3368
802de3da 3369 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3370 logfp = fopen(sb.buf, "r");
3371 strbuf_release(&sb);
7bd9bcf3
MH
3372 if (!logfp)
3373 return -1;
3374
3375 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3376 ret = show_one_reflog_ent(&sb, fn, cb_data);
3377 fclose(logfp);
3378 strbuf_release(&sb);
3379 return ret;
3380}
7bd9bcf3 3381
2880d16f
MH
3382struct files_reflog_iterator {
3383 struct ref_iterator base;
7bd9bcf3 3384
2880d16f
MH
3385 struct dir_iterator *dir_iterator;
3386 struct object_id oid;
3387};
7bd9bcf3 3388
2880d16f
MH
3389static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
3390{
3391 struct files_reflog_iterator *iter =
3392 (struct files_reflog_iterator *)ref_iterator;
3393 struct dir_iterator *diter = iter->dir_iterator;
3394 int ok;
3395
3396 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
3397 int flags;
3398
3399 if (!S_ISREG(diter->st.st_mode))
7bd9bcf3 3400 continue;
2880d16f
MH
3401 if (diter->basename[0] == '.')
3402 continue;
3403 if (ends_with(diter->basename, ".lock"))
7bd9bcf3 3404 continue;
7bd9bcf3 3405
2880d16f
MH
3406 if (read_ref_full(diter->relative_path, 0,
3407 iter->oid.hash, &flags)) {
3408 error("bad ref for %s", diter->path.buf);
3409 continue;
7bd9bcf3 3410 }
2880d16f
MH
3411
3412 iter->base.refname = diter->relative_path;
3413 iter->base.oid = &iter->oid;
3414 iter->base.flags = flags;
3415 return ITER_OK;
7bd9bcf3 3416 }
2880d16f
MH
3417
3418 iter->dir_iterator = NULL;
3419 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
3420 ok = ITER_ERROR;
3421 return ok;
3422}
3423
3424static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
3425 struct object_id *peeled)
3426{
3427 die("BUG: ref_iterator_peel() called for reflog_iterator");
3428}
3429
3430static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
3431{
3432 struct files_reflog_iterator *iter =
3433 (struct files_reflog_iterator *)ref_iterator;
3434 int ok = ITER_DONE;
3435
3436 if (iter->dir_iterator)
3437 ok = dir_iterator_abort(iter->dir_iterator);
3438
3439 base_ref_iterator_free(ref_iterator);
3440 return ok;
3441}
3442
3443static struct ref_iterator_vtable files_reflog_iterator_vtable = {
3444 files_reflog_iterator_advance,
3445 files_reflog_iterator_peel,
3446 files_reflog_iterator_abort
3447};
3448
e3688bd6 3449static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2880d16f 3450{
802de3da
NTND
3451 struct files_ref_store *refs =
3452 files_downcast(ref_store, 0, "reflog_iterator_begin");
2880d16f
MH
3453 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
3454 struct ref_iterator *ref_iterator = &iter->base;
e9dcc305 3455 struct strbuf sb = STRBUF_INIT;
2880d16f
MH
3456
3457 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
802de3da 3458 files_reflog_path(refs, &sb, NULL);
e9dcc305
NTND
3459 iter->dir_iterator = dir_iterator_begin(sb.buf);
3460 strbuf_release(&sb);
2880d16f 3461 return ref_iterator;
7bd9bcf3
MH
3462}
3463
7bd9bcf3
MH
3464static int ref_update_reject_duplicates(struct string_list *refnames,
3465 struct strbuf *err)
3466{
3467 int i, n = refnames->nr;
3468
3469 assert(err);
3470
3471 for (i = 1; i < n; i++)
3472 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3473 strbuf_addf(err,
0568c8e9 3474 "multiple updates for ref '%s' not allowed.",
7bd9bcf3
MH
3475 refnames->items[i].string);
3476 return 1;
3477 }
3478 return 0;
3479}
3480
165056b2 3481/*
92b1551b
MH
3482 * If update is a direct update of head_ref (the reference pointed to
3483 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
3484 */
3485static int split_head_update(struct ref_update *update,
3486 struct ref_transaction *transaction,
3487 const char *head_ref,
3488 struct string_list *affected_refnames,
3489 struct strbuf *err)
3490{
3491 struct string_list_item *item;
3492 struct ref_update *new_update;
3493
3494 if ((update->flags & REF_LOG_ONLY) ||
3495 (update->flags & REF_ISPRUNING) ||
3496 (update->flags & REF_UPDATE_VIA_HEAD))
3497 return 0;
3498
3499 if (strcmp(update->refname, head_ref))
3500 return 0;
3501
3502 /*
3503 * First make sure that HEAD is not already in the
3504 * transaction. This insertion is O(N) in the transaction
3505 * size, but it happens at most once per transaction.
3506 */
3507 item = string_list_insert(affected_refnames, "HEAD");
3508 if (item->util) {
3509 /* An entry already existed */
3510 strbuf_addf(err,
3511 "multiple updates for 'HEAD' (including one "
3512 "via its referent '%s') are not allowed",
3513 update->refname);
3514 return TRANSACTION_NAME_CONFLICT;
3515 }
3516
3517 new_update = ref_transaction_add_update(
3518 transaction, "HEAD",
3519 update->flags | REF_LOG_ONLY | REF_NODEREF,
3520 update->new_sha1, update->old_sha1,
3521 update->msg);
3522
3523 item->util = new_update;
3524
3525 return 0;
3526}
3527
3528/*
3529 * update is for a symref that points at referent and doesn't have
3530 * REF_NODEREF set. Split it into two updates:
3531 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
3532 * - A new, separate update for the referent reference
3533 * Note that the new update will itself be subject to splitting when
3534 * the iteration gets to it.
3535 */
fcc42ea0
MH
3536static int split_symref_update(struct files_ref_store *refs,
3537 struct ref_update *update,
92b1551b
MH
3538 const char *referent,
3539 struct ref_transaction *transaction,
3540 struct string_list *affected_refnames,
3541 struct strbuf *err)
3542{
3543 struct string_list_item *item;
3544 struct ref_update *new_update;
3545 unsigned int new_flags;
3546
3547 /*
3548 * First make sure that referent is not already in the
3549 * transaction. This insertion is O(N) in the transaction
3550 * size, but it happens at most once per symref in a
3551 * transaction.
3552 */
3553 item = string_list_insert(affected_refnames, referent);
3554 if (item->util) {
3555 /* An entry already existed */
3556 strbuf_addf(err,
3557 "multiple updates for '%s' (including one "
3558 "via symref '%s') are not allowed",
3559 referent, update->refname);
3560 return TRANSACTION_NAME_CONFLICT;
3561 }
3562
3563 new_flags = update->flags;
3564 if (!strcmp(update->refname, "HEAD")) {
3565 /*
3566 * Record that the new update came via HEAD, so that
3567 * when we process it, split_head_update() doesn't try
3568 * to add another reflog update for HEAD. Note that
3569 * this bit will be propagated if the new_update
3570 * itself needs to be split.
3571 */
3572 new_flags |= REF_UPDATE_VIA_HEAD;
3573 }
3574
3575 new_update = ref_transaction_add_update(
3576 transaction, referent, new_flags,
3577 update->new_sha1, update->old_sha1,
3578 update->msg);
3579
6e30b2f6
MH
3580 new_update->parent_update = update;
3581
3582 /*
3583 * Change the symbolic ref update to log only. Also, it
3584 * doesn't need to check its old SHA-1 value, as that will be
3585 * done when new_update is processed.
3586 */
92b1551b 3587 update->flags |= REF_LOG_ONLY | REF_NODEREF;
6e30b2f6 3588 update->flags &= ~REF_HAVE_OLD;
92b1551b
MH
3589
3590 item->util = new_update;
3591
3592 return 0;
3593}
3594
6e30b2f6
MH
3595/*
3596 * Return the refname under which update was originally requested.
3597 */
3598static const char *original_update_refname(struct ref_update *update)
3599{
3600 while (update->parent_update)
3601 update = update->parent_update;
3602
3603 return update->refname;
3604}
3605
e3f51039
MH
3606/*
3607 * Check whether the REF_HAVE_OLD and old_oid values stored in update
3608 * are consistent with oid, which is the reference's current value. If
3609 * everything is OK, return 0; otherwise, write an error message to
3610 * err and return -1.
3611 */
3612static int check_old_oid(struct ref_update *update, struct object_id *oid,
3613 struct strbuf *err)
3614{
3615 if (!(update->flags & REF_HAVE_OLD) ||
3616 !hashcmp(oid->hash, update->old_sha1))
3617 return 0;
3618
3619 if (is_null_sha1(update->old_sha1))
3620 strbuf_addf(err, "cannot lock ref '%s': "
3621 "reference already exists",
3622 original_update_refname(update));
3623 else if (is_null_oid(oid))
3624 strbuf_addf(err, "cannot lock ref '%s': "
3625 "reference is missing but expected %s",
3626 original_update_refname(update),
3627 sha1_to_hex(update->old_sha1));
3628 else
3629 strbuf_addf(err, "cannot lock ref '%s': "
3630 "is at %s but expected %s",
3631 original_update_refname(update),
3632 oid_to_hex(oid),
3633 sha1_to_hex(update->old_sha1));
3634
3635 return -1;
3636}
3637
92b1551b
MH
3638/*
3639 * Prepare for carrying out update:
3640 * - Lock the reference referred to by update.
3641 * - Read the reference under lock.
3642 * - Check that its old SHA-1 value (if specified) is correct, and in
3643 * any case record it in update->lock->old_oid for later use when
3644 * writing the reflog.
3645 * - If it is a symref update without REF_NODEREF, split it up into a
3646 * REF_LOG_ONLY update of the symref and add a separate update for
3647 * the referent to transaction.
3648 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
3649 * update of HEAD.
165056b2 3650 */
b3bbbc5c
MH
3651static int lock_ref_for_update(struct files_ref_store *refs,
3652 struct ref_update *update,
165056b2 3653 struct ref_transaction *transaction,
92b1551b 3654 const char *head_ref,
165056b2
MH
3655 struct string_list *affected_refnames,
3656 struct strbuf *err)
3657{
92b1551b
MH
3658 struct strbuf referent = STRBUF_INIT;
3659 int mustexist = (update->flags & REF_HAVE_OLD) &&
3660 !is_null_sha1(update->old_sha1);
165056b2 3661 int ret;
92b1551b 3662 struct ref_lock *lock;
165056b2 3663
32c597e7 3664 files_assert_main_repository(refs, "lock_ref_for_update");
b3bbbc5c 3665
92b1551b 3666 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
165056b2 3667 update->flags |= REF_DELETING;
92b1551b
MH
3668
3669 if (head_ref) {
3670 ret = split_head_update(update, transaction, head_ref,
3671 affected_refnames, err);
3672 if (ret)
3673 return ret;
3674 }
3675
f7b0a987 3676 ret = lock_raw_ref(refs, update->refname, mustexist,
92b1551b 3677 affected_refnames, NULL,
7d618264 3678 &lock, &referent,
92b1551b 3679 &update->type, err);