files-backend: add and use files_ref_path()
[git/git.git] / refs / files-backend.c
CommitLineData
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1#include "../cache.h"
2#include "../refs.h"
3#include "refs-internal.h"
3bc581b9 4#include "../iterator.h"
2880d16f 5#include "../dir-iterator.h"
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6#include "../lockfile.h"
7#include "../object.h"
8#include "../dir.h"
9
10struct ref_lock {
11 char *ref_name;
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12 struct lock_file *lk;
13 struct object_id old_oid;
14};
15
16struct ref_entry;
17
18/*
19 * Information used (along with the information in ref_entry) to
20 * describe a single cached reference. This data structure only
21 * occurs embedded in a union in struct ref_entry, and only when
22 * (ref_entry->flag & REF_DIR) is zero.
23 */
24struct ref_value {
25 /*
26 * The name of the object to which this reference resolves
27 * (which may be a tag object). If REF_ISBROKEN, this is
28 * null. If REF_ISSYMREF, then this is the name of the object
29 * referred to by the last reference in the symlink chain.
30 */
31 struct object_id oid;
32
33 /*
34 * If REF_KNOWS_PEELED, then this field holds the peeled value
35 * of this reference, or null if the reference is known not to
36 * be peelable. See the documentation for peel_ref() for an
37 * exact definition of "peelable".
38 */
39 struct object_id peeled;
40};
41
65a0a8e5 42struct files_ref_store;
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43
44/*
45 * Information used (along with the information in ref_entry) to
46 * describe a level in the hierarchy of references. This data
47 * structure only occurs embedded in a union in struct ref_entry, and
48 * only when (ref_entry.flag & REF_DIR) is set. In that case,
49 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
50 * in the directory have already been read:
51 *
52 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
53 * or packed references, already read.
54 *
55 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
56 * references that hasn't been read yet (nor has any of its
57 * subdirectories).
58 *
59 * Entries within a directory are stored within a growable array of
60 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
61 * sorted are sorted by their component name in strcmp() order and the
62 * remaining entries are unsorted.
63 *
64 * Loose references are read lazily, one directory at a time. When a
65 * directory of loose references is read, then all of the references
66 * in that directory are stored, and REF_INCOMPLETE stubs are created
67 * for any subdirectories, but the subdirectories themselves are not
68 * read. The reading is triggered by get_ref_dir().
69 */
70struct ref_dir {
71 int nr, alloc;
72
73 /*
74 * Entries with index 0 <= i < sorted are sorted by name. New
75 * entries are appended to the list unsorted, and are sorted
76 * only when required; thus we avoid the need to sort the list
77 * after the addition of every reference.
78 */
79 int sorted;
80
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81 /* A pointer to the files_ref_store that contains this ref_dir. */
82 struct files_ref_store *ref_store;
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83
84 struct ref_entry **entries;
85};
86
87/*
88 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
89 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
90 * public values; see refs.h.
91 */
92
93/*
94 * The field ref_entry->u.value.peeled of this value entry contains
95 * the correct peeled value for the reference, which might be
96 * null_sha1 if the reference is not a tag or if it is broken.
97 */
98#define REF_KNOWS_PEELED 0x10
99
100/* ref_entry represents a directory of references */
101#define REF_DIR 0x20
102
103/*
104 * Entry has not yet been read from disk (used only for REF_DIR
105 * entries representing loose references)
106 */
107#define REF_INCOMPLETE 0x40
108
109/*
110 * A ref_entry represents either a reference or a "subdirectory" of
111 * references.
112 *
113 * Each directory in the reference namespace is represented by a
114 * ref_entry with (flags & REF_DIR) set and containing a subdir member
115 * that holds the entries in that directory that have been read so
116 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
117 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
118 * used for loose reference directories.
119 *
120 * References are represented by a ref_entry with (flags & REF_DIR)
121 * unset and a value member that describes the reference's value. The
122 * flag member is at the ref_entry level, but it is also needed to
123 * interpret the contents of the value field (in other words, a
124 * ref_value object is not very much use without the enclosing
125 * ref_entry).
126 *
127 * Reference names cannot end with slash and directories' names are
128 * always stored with a trailing slash (except for the top-level
129 * directory, which is always denoted by ""). This has two nice
130 * consequences: (1) when the entries in each subdir are sorted
131 * lexicographically by name (as they usually are), the references in
132 * a whole tree can be generated in lexicographic order by traversing
133 * the tree in left-to-right, depth-first order; (2) the names of
134 * references and subdirectories cannot conflict, and therefore the
135 * presence of an empty subdirectory does not block the creation of a
136 * similarly-named reference. (The fact that reference names with the
137 * same leading components can conflict *with each other* is a
138 * separate issue that is regulated by verify_refname_available().)
139 *
140 * Please note that the name field contains the fully-qualified
141 * reference (or subdirectory) name. Space could be saved by only
142 * storing the relative names. But that would require the full names
143 * to be generated on the fly when iterating in do_for_each_ref(), and
144 * would break callback functions, who have always been able to assume
145 * that the name strings that they are passed will not be freed during
146 * the iteration.
147 */
148struct ref_entry {
149 unsigned char flag; /* ISSYMREF? ISPACKED? */
150 union {
151 struct ref_value value; /* if not (flags&REF_DIR) */
152 struct ref_dir subdir; /* if (flags&REF_DIR) */
153 } u;
154 /*
155 * The full name of the reference (e.g., "refs/heads/master")
156 * or the full name of the directory with a trailing slash
157 * (e.g., "refs/heads/"):
158 */
159 char name[FLEX_ARRAY];
160};
161
162static void read_loose_refs(const char *dirname, struct ref_dir *dir);
163static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len);
65a0a8e5 164static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
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165 const char *dirname, size_t len,
166 int incomplete);
167static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
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168static int files_log_ref_write(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/*
a8739244
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/*
a8739244
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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{
a8739244
MH
546 return ref_resolves_to_object(entry->name,
547 &entry->u.value.oid, entry->flag);
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MH
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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MH
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
MH
919
920 /*
921 * The name of the submodule represented by this object, or
9c7d772b
MH
922 * NULL if it represents the main repository's reference
923 * store:
32c597e7
MH
924 */
925 const char *submodule;
926
33dfb9f3
NTND
927 char *packed_refs_path;
928
7bd9bcf3
MH
929 struct ref_entry *loose;
930 struct packed_ref_cache *packed;
00eebe35 931};
7bd9bcf3
MH
932
933/* Lock used for the main packed-refs file: */
934static struct lock_file packlock;
935
936/*
937 * Increment the reference count of *packed_refs.
938 */
939static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
940{
941 packed_refs->referrers++;
942}
943
944/*
945 * Decrease the reference count of *packed_refs. If it goes to zero,
946 * free *packed_refs and return true; otherwise return false.
947 */
948static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
949{
950 if (!--packed_refs->referrers) {
951 free_ref_entry(packed_refs->root);
952 stat_validity_clear(&packed_refs->validity);
953 free(packed_refs);
954 return 1;
955 } else {
956 return 0;
957 }
958}
959
65a0a8e5 960static void clear_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
961{
962 if (refs->packed) {
963 struct packed_ref_cache *packed_refs = refs->packed;
964
965 if (packed_refs->lock)
966 die("internal error: packed-ref cache cleared while locked");
967 refs->packed = NULL;
968 release_packed_ref_cache(packed_refs);
969 }
970}
971
65a0a8e5 972static void clear_loose_ref_cache(struct files_ref_store *refs)
7bd9bcf3
MH
973{
974 if (refs->loose) {
975 free_ref_entry(refs->loose);
976 refs->loose = NULL;
977 }
978}
979
a2d5156c
JK
980/*
981 * Create a new submodule ref cache and add it to the internal
982 * set of caches.
983 */
00eebe35 984static struct ref_store *files_ref_store_create(const char *submodule)
7bd9bcf3 985{
00eebe35
MH
986 struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
987 struct ref_store *ref_store = (struct ref_store *)refs;
7bd9bcf3 988
fbfd0a29 989 base_ref_store_init(ref_store, &refs_be_files);
7bd9bcf3 990
33dfb9f3
NTND
991 if (submodule) {
992 refs->submodule = xstrdup(submodule);
993 refs->packed_refs_path = git_pathdup_submodule(
994 refs->submodule, "packed-refs");
995 return ref_store;
996 }
997
998 refs->packed_refs_path = git_pathdup("packed-refs");
7bd9bcf3 999
00eebe35 1000 return ref_store;
a2d5156c 1001}
7bd9bcf3 1002
32c597e7
MH
1003/*
1004 * Die if refs is for a submodule (i.e., not for the main repository).
1005 * caller is used in any necessary error messages.
1006 */
1007static void files_assert_main_repository(struct files_ref_store *refs,
1008 const char *caller)
1009{
9c7d772b 1010 if (refs->submodule)
32c597e7
MH
1011 die("BUG: %s called for a submodule", caller);
1012}
1013
a2d5156c 1014/*
00eebe35
MH
1015 * Downcast ref_store to files_ref_store. Die if ref_store is not a
1016 * files_ref_store. If submodule_allowed is not true, then also die if
1017 * files_ref_store is for a submodule (i.e., not for the main
1018 * repository). caller is used in any necessary error messages.
a2d5156c 1019 */
00eebe35
MH
1020static struct files_ref_store *files_downcast(
1021 struct ref_store *ref_store, int submodule_allowed,
1022 const char *caller)
a2d5156c 1023{
32c597e7
MH
1024 struct files_ref_store *refs;
1025
00eebe35
MH
1026 if (ref_store->be != &refs_be_files)
1027 die("BUG: ref_store is type \"%s\" not \"files\" in %s",
1028 ref_store->be->name, caller);
2eed2780 1029
32c597e7
MH
1030 refs = (struct files_ref_store *)ref_store;
1031
00eebe35 1032 if (!submodule_allowed)
32c597e7 1033 files_assert_main_repository(refs, caller);
2eed2780 1034
32c597e7 1035 return refs;
7bd9bcf3
MH
1036}
1037
1038/* The length of a peeled reference line in packed-refs, including EOL: */
1039#define PEELED_LINE_LENGTH 42
1040
1041/*
1042 * The packed-refs header line that we write out. Perhaps other
1043 * traits will be added later. The trailing space is required.
1044 */
1045static const char PACKED_REFS_HEADER[] =
1046 "# pack-refs with: peeled fully-peeled \n";
1047
1048/*
1049 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1050 * Return a pointer to the refname within the line (null-terminated),
1051 * or NULL if there was a problem.
1052 */
1053static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1054{
1055 const char *ref;
1056
1057 /*
1058 * 42: the answer to everything.
1059 *
1060 * In this case, it happens to be the answer to
1061 * 40 (length of sha1 hex representation)
1062 * +1 (space in between hex and name)
1063 * +1 (newline at the end of the line)
1064 */
1065 if (line->len <= 42)
1066 return NULL;
1067
1068 if (get_sha1_hex(line->buf, sha1) < 0)
1069 return NULL;
1070 if (!isspace(line->buf[40]))
1071 return NULL;
1072
1073 ref = line->buf + 41;
1074 if (isspace(*ref))
1075 return NULL;
1076
1077 if (line->buf[line->len - 1] != '\n')
1078 return NULL;
1079 line->buf[--line->len] = 0;
1080
1081 return ref;
1082}
1083
1084/*
1085 * Read f, which is a packed-refs file, into dir.
1086 *
1087 * A comment line of the form "# pack-refs with: " may contain zero or
1088 * more traits. We interpret the traits as follows:
1089 *
1090 * No traits:
1091 *
1092 * Probably no references are peeled. But if the file contains a
1093 * peeled value for a reference, we will use it.
1094 *
1095 * peeled:
1096 *
1097 * References under "refs/tags/", if they *can* be peeled, *are*
1098 * peeled in this file. References outside of "refs/tags/" are
1099 * probably not peeled even if they could have been, but if we find
1100 * a peeled value for such a reference we will use it.
1101 *
1102 * fully-peeled:
1103 *
1104 * All references in the file that can be peeled are peeled.
1105 * Inversely (and this is more important), any references in the
1106 * file for which no peeled value is recorded is not peelable. This
1107 * trait should typically be written alongside "peeled" for
1108 * compatibility with older clients, but we do not require it
1109 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1110 */
1111static void read_packed_refs(FILE *f, struct ref_dir *dir)
1112{
1113 struct ref_entry *last = NULL;
1114 struct strbuf line = STRBUF_INIT;
1115 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1116
1117 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1118 unsigned char sha1[20];
1119 const char *refname;
1120 const char *traits;
1121
1122 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1123 if (strstr(traits, " fully-peeled "))
1124 peeled = PEELED_FULLY;
1125 else if (strstr(traits, " peeled "))
1126 peeled = PEELED_TAGS;
1127 /* perhaps other traits later as well */
1128 continue;
1129 }
1130
1131 refname = parse_ref_line(&line, sha1);
1132 if (refname) {
1133 int flag = REF_ISPACKED;
1134
1135 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1136 if (!refname_is_safe(refname))
1137 die("packed refname is dangerous: %s", refname);
1138 hashclr(sha1);
1139 flag |= REF_BAD_NAME | REF_ISBROKEN;
1140 }
1141 last = create_ref_entry(refname, sha1, flag, 0);
1142 if (peeled == PEELED_FULLY ||
1143 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1144 last->flag |= REF_KNOWS_PEELED;
1145 add_ref(dir, last);
1146 continue;
1147 }
1148 if (last &&
1149 line.buf[0] == '^' &&
1150 line.len == PEELED_LINE_LENGTH &&
1151 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1152 !get_sha1_hex(line.buf + 1, sha1)) {
1153 hashcpy(last->u.value.peeled.hash, sha1);
1154 /*
1155 * Regardless of what the file header said,
1156 * we definitely know the value of *this*
1157 * reference:
1158 */
1159 last->flag |= REF_KNOWS_PEELED;
1160 }
1161 }
1162
1163 strbuf_release(&line);
1164}
1165
33dfb9f3
NTND
1166static const char *files_packed_refs_path(struct files_ref_store *refs)
1167{
1168 return refs->packed_refs_path;
1169}
1170
802de3da
NTND
1171static void files_reflog_path(struct files_ref_store *refs,
1172 struct strbuf *sb,
1173 const char *refname)
1174{
1175 if (!refname) {
1176 strbuf_git_path(sb, "logs");
1177 return;
1178 }
1179
1180 strbuf_git_path(sb, "logs/%s", refname);
1181}
1182
19e02f4f
NTND
1183static void files_ref_path(struct files_ref_store *refs,
1184 struct strbuf *sb,
1185 const char *refname)
1186{
1187 if (refs->submodule) {
1188 strbuf_git_path_submodule(sb, refs->submodule, "%s", refname);
1189 return;
1190 }
1191
1192 strbuf_git_path(sb, "%s", refname);
1193}
1194
7bd9bcf3 1195/*
65a0a8e5
MH
1196 * Get the packed_ref_cache for the specified files_ref_store,
1197 * creating it if necessary.
7bd9bcf3 1198 */
65a0a8e5 1199static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
7bd9bcf3 1200{
33dfb9f3 1201 const char *packed_refs_file = files_packed_refs_path(refs);
7bd9bcf3
MH
1202
1203 if (refs->packed &&
1204 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1205 clear_packed_ref_cache(refs);
1206
1207 if (!refs->packed) {
1208 FILE *f;
1209
1210 refs->packed = xcalloc(1, sizeof(*refs->packed));
1211 acquire_packed_ref_cache(refs->packed);
1212 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1213 f = fopen(packed_refs_file, "r");
1214 if (f) {
1215 stat_validity_update(&refs->packed->validity, fileno(f));
1216 read_packed_refs(f, get_ref_dir(refs->packed->root));
1217 fclose(f);
1218 }
1219 }
7bd9bcf3
MH
1220 return refs->packed;
1221}
1222
1223static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1224{
1225 return get_ref_dir(packed_ref_cache->root);
1226}
1227
65a0a8e5 1228static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1229{
1230 return get_packed_ref_dir(get_packed_ref_cache(refs));
1231}
1232
1233/*
1234 * Add a reference to the in-memory packed reference cache. This may
1235 * only be called while the packed-refs file is locked (see
1236 * lock_packed_refs()). To actually write the packed-refs file, call
1237 * commit_packed_refs().
1238 */
d99825ab
MH
1239static void add_packed_ref(struct files_ref_store *refs,
1240 const char *refname, const unsigned char *sha1)
7bd9bcf3 1241{
00eebe35 1242 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
1243
1244 if (!packed_ref_cache->lock)
1245 die("internal error: packed refs not locked");
1246 add_ref(get_packed_ref_dir(packed_ref_cache),
1247 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1248}
1249
1250/*
1251 * Read the loose references from the namespace dirname into dir
1252 * (without recursing). dirname must end with '/'. dir must be the
1253 * directory entry corresponding to dirname.
1254 */
1255static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1256{
65a0a8e5 1257 struct files_ref_store *refs = dir->ref_store;
7bd9bcf3
MH
1258 DIR *d;
1259 struct dirent *de;
1260 int dirnamelen = strlen(dirname);
1261 struct strbuf refname;
1262 struct strbuf path = STRBUF_INIT;
1263 size_t path_baselen;
1264
19e02f4f 1265 files_ref_path(refs, &path, dirname);
7bd9bcf3
MH
1266 path_baselen = path.len;
1267
1268 d = opendir(path.buf);
1269 if (!d) {
1270 strbuf_release(&path);
1271 return;
1272 }
1273
1274 strbuf_init(&refname, dirnamelen + 257);
1275 strbuf_add(&refname, dirname, dirnamelen);
1276
1277 while ((de = readdir(d)) != NULL) {
1278 unsigned char sha1[20];
1279 struct stat st;
1280 int flag;
1281
1282 if (de->d_name[0] == '.')
1283 continue;
1284 if (ends_with(de->d_name, ".lock"))
1285 continue;
1286 strbuf_addstr(&refname, de->d_name);
1287 strbuf_addstr(&path, de->d_name);
1288 if (stat(path.buf, &st) < 0) {
1289 ; /* silently ignore */
1290 } else if (S_ISDIR(st.st_mode)) {
1291 strbuf_addch(&refname, '/');
1292 add_entry_to_dir(dir,
1293 create_dir_entry(refs, refname.buf,
1294 refname.len, 1));
1295 } else {
3c0cb0cb
MH
1296 if (!resolve_ref_recursively(&refs->base,
1297 refname.buf,
1298 RESOLVE_REF_READING,
1299 sha1, &flag)) {
7bd9bcf3
MH
1300 hashclr(sha1);
1301 flag |= REF_ISBROKEN;
1302 } else if (is_null_sha1(sha1)) {
1303 /*
1304 * It is so astronomically unlikely
1305 * that NULL_SHA1 is the SHA-1 of an
1306 * actual object that we consider its
1307 * appearance in a loose reference
1308 * file to be repo corruption
1309 * (probably due to a software bug).
1310 */
1311 flag |= REF_ISBROKEN;
1312 }
1313
1314 if (check_refname_format(refname.buf,
1315 REFNAME_ALLOW_ONELEVEL)) {
1316 if (!refname_is_safe(refname.buf))
1317 die("loose refname is dangerous: %s", refname.buf);
1318 hashclr(sha1);
1319 flag |= REF_BAD_NAME | REF_ISBROKEN;
1320 }
1321 add_entry_to_dir(dir,
1322 create_ref_entry(refname.buf, sha1, flag, 0));
1323 }
1324 strbuf_setlen(&refname, dirnamelen);
1325 strbuf_setlen(&path, path_baselen);
1326 }
1327 strbuf_release(&refname);
1328 strbuf_release(&path);
1329 closedir(d);
1330}
1331
65a0a8e5 1332static struct ref_dir *get_loose_refs(struct files_ref_store *refs)
7bd9bcf3
MH
1333{
1334 if (!refs->loose) {
1335 /*
1336 * Mark the top-level directory complete because we
1337 * are about to read the only subdirectory that can
1338 * hold references:
1339 */
1340 refs->loose = create_dir_entry(refs, "", 0, 0);
1341 /*
1342 * Create an incomplete entry for "refs/":
1343 */
1344 add_entry_to_dir(get_ref_dir(refs->loose),
1345 create_dir_entry(refs, "refs/", 5, 1));
1346 }
1347 return get_ref_dir(refs->loose);
1348}
1349
7bd9bcf3
MH
1350/*
1351 * Return the ref_entry for the given refname from the packed
1352 * references. If it does not exist, return NULL.
1353 */
f0d21efc
MH
1354static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
1355 const char *refname)
7bd9bcf3 1356{
00eebe35 1357 return find_ref(get_packed_refs(refs), refname);
7bd9bcf3
MH
1358}
1359
1360/*
419c6f4c 1361 * A loose ref file doesn't exist; check for a packed ref.
7bd9bcf3 1362 */
611118d0
MH
1363static int resolve_packed_ref(struct files_ref_store *refs,
1364 const char *refname,
1365 unsigned char *sha1, unsigned int *flags)
7bd9bcf3
MH
1366{
1367 struct ref_entry *entry;
1368
1369 /*
1370 * The loose reference file does not exist; check for a packed
1371 * reference.
1372 */
f0d21efc 1373 entry = get_packed_ref(refs, refname);
7bd9bcf3
MH
1374 if (entry) {
1375 hashcpy(sha1, entry->u.value.oid.hash);
a70a93b7 1376 *flags |= REF_ISPACKED;
7bd9bcf3
MH
1377 return 0;
1378 }
419c6f4c
MH
1379 /* refname is not a packed reference. */
1380 return -1;
7bd9bcf3
MH
1381}
1382
e1e33b72
MH
1383static int files_read_raw_ref(struct ref_store *ref_store,
1384 const char *refname, unsigned char *sha1,
1385 struct strbuf *referent, unsigned int *type)
7bd9bcf3 1386{
4308651c 1387 struct files_ref_store *refs =
34c7ad8f 1388 files_downcast(ref_store, 1, "read_raw_ref");
42a38cf7
MH
1389 struct strbuf sb_contents = STRBUF_INIT;
1390 struct strbuf sb_path = STRBUF_INIT;
7048653a
DT
1391 const char *path;
1392 const char *buf;
1393 struct stat st;
1394 int fd;
42a38cf7
MH
1395 int ret = -1;
1396 int save_errno;
e8c42cb9 1397 int remaining_retries = 3;
7bd9bcf3 1398
fa96ea1b 1399 *type = 0;
42a38cf7 1400 strbuf_reset(&sb_path);
34c7ad8f 1401
19e02f4f 1402 files_ref_path(refs, &sb_path, refname);
34c7ad8f 1403
42a38cf7 1404 path = sb_path.buf;
7bd9bcf3 1405
7048653a
DT
1406stat_ref:
1407 /*
1408 * We might have to loop back here to avoid a race
1409 * condition: first we lstat() the file, then we try
1410 * to read it as a link or as a file. But if somebody
1411 * changes the type of the file (file <-> directory
1412 * <-> symlink) between the lstat() and reading, then
1413 * we don't want to report that as an error but rather
1414 * try again starting with the lstat().
e8c42cb9
JK
1415 *
1416 * We'll keep a count of the retries, though, just to avoid
1417 * any confusing situation sending us into an infinite loop.
7048653a 1418 */
7bd9bcf3 1419
e8c42cb9
JK
1420 if (remaining_retries-- <= 0)
1421 goto out;
1422
7048653a
DT
1423 if (lstat(path, &st) < 0) {
1424 if (errno != ENOENT)
42a38cf7 1425 goto out;
611118d0 1426 if (resolve_packed_ref(refs, refname, sha1, type)) {
7048653a 1427 errno = ENOENT;
42a38cf7 1428 goto out;
7bd9bcf3 1429 }
42a38cf7
MH
1430 ret = 0;
1431 goto out;
7bd9bcf3 1432 }
7bd9bcf3 1433
7048653a
DT
1434 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1435 if (S_ISLNK(st.st_mode)) {
42a38cf7
MH
1436 strbuf_reset(&sb_contents);
1437 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
7048653a 1438 if (errno == ENOENT || errno == EINVAL)
7bd9bcf3
MH
1439 /* inconsistent with lstat; retry */
1440 goto stat_ref;
1441 else
42a38cf7 1442 goto out;
7bd9bcf3 1443 }
42a38cf7
MH
1444 if (starts_with(sb_contents.buf, "refs/") &&
1445 !check_refname_format(sb_contents.buf, 0)) {
92b38093 1446 strbuf_swap(&sb_contents, referent);
3a0b6b9a 1447 *type |= REF_ISSYMREF;
42a38cf7
MH
1448 ret = 0;
1449 goto out;
7bd9bcf3 1450 }
3f7bd767
JK
1451 /*
1452 * It doesn't look like a refname; fall through to just
1453 * treating it like a non-symlink, and reading whatever it
1454 * points to.
1455 */
7048653a 1456 }
7bd9bcf3 1457
7048653a
DT
1458 /* Is it a directory? */
1459 if (S_ISDIR(st.st_mode)) {
e167a567
MH
1460 /*
1461 * Even though there is a directory where the loose
1462 * ref is supposed to be, there could still be a
1463 * packed ref:
1464 */
611118d0 1465 if (resolve_packed_ref(refs, refname, sha1, type)) {
e167a567
MH
1466 errno = EISDIR;
1467 goto out;
1468 }
1469 ret = 0;
42a38cf7 1470 goto out;
7048653a
DT
1471 }
1472
1473 /*
1474 * Anything else, just open it and try to use it as
1475 * a ref
1476 */
1477 fd = open(path, O_RDONLY);
1478 if (fd < 0) {
3f7bd767 1479 if (errno == ENOENT && !S_ISLNK(st.st_mode))
7048653a
DT
1480 /* inconsistent with lstat; retry */
1481 goto stat_ref;
1482 else
42a38cf7 1483 goto out;
7048653a 1484 }
42a38cf7
MH
1485 strbuf_reset(&sb_contents);
1486 if (strbuf_read(&sb_contents, fd, 256) < 0) {
7048653a
DT
1487 int save_errno = errno;
1488 close(fd);
1489 errno = save_errno;
42a38cf7 1490 goto out;
7048653a
DT
1491 }
1492 close(fd);
42a38cf7
MH
1493 strbuf_rtrim(&sb_contents);
1494 buf = sb_contents.buf;
7048653a
DT
1495 if (starts_with(buf, "ref:")) {
1496 buf += 4;
7bd9bcf3
MH
1497 while (isspace(*buf))
1498 buf++;
7048653a 1499
92b38093
MH
1500 strbuf_reset(referent);
1501 strbuf_addstr(referent, buf);
3a0b6b9a 1502 *type |= REF_ISSYMREF;
42a38cf7
MH
1503 ret = 0;
1504 goto out;
7bd9bcf3 1505 }
7bd9bcf3 1506
7048653a
DT
1507 /*
1508 * Please note that FETCH_HEAD has additional
1509 * data after the sha.
1510 */
1511 if (get_sha1_hex(buf, sha1) ||
1512 (buf[40] != '\0' && !isspace(buf[40]))) {
3a0b6b9a 1513 *type |= REF_ISBROKEN;
7048653a 1514 errno = EINVAL;
42a38cf7 1515 goto out;
7048653a
DT
1516 }
1517
42a38cf7 1518 ret = 0;
7bd9bcf3 1519
42a38cf7
MH
1520out:
1521 save_errno = errno;
7bd9bcf3
MH
1522 strbuf_release(&sb_path);
1523 strbuf_release(&sb_contents);
42a38cf7 1524 errno = save_errno;
7bd9bcf3
MH
1525 return ret;
1526}
1527
8415d247
MH
1528static void unlock_ref(struct ref_lock *lock)
1529{
1530 /* Do not free lock->lk -- atexit() still looks at them */
1531 if (lock->lk)
1532 rollback_lock_file(lock->lk);
1533 free(lock->ref_name);
8415d247
MH
1534 free(lock);
1535}
1536
92b1551b
MH
1537/*
1538 * Lock refname, without following symrefs, and set *lock_p to point
1539 * at a newly-allocated lock object. Fill in lock->old_oid, referent,
1540 * and type similarly to read_raw_ref().
1541 *
1542 * The caller must verify that refname is a "safe" reference name (in
1543 * the sense of refname_is_safe()) before calling this function.
1544 *
1545 * If the reference doesn't already exist, verify that refname doesn't
1546 * have a D/F conflict with any existing references. extras and skip
1547 * are passed to verify_refname_available_dir() for this check.
1548 *
1549 * If mustexist is not set and the reference is not found or is
1550 * broken, lock the reference anyway but clear sha1.
1551 *
1552 * Return 0 on success. On failure, write an error message to err and
1553 * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
1554 *
1555 * Implementation note: This function is basically
1556 *
1557 * lock reference
1558 * read_raw_ref()
1559 *
1560 * but it includes a lot more code to
1561 * - Deal with possible races with other processes
1562 * - Avoid calling verify_refname_available_dir() when it can be
1563 * avoided, namely if we were successfully able to read the ref
1564 * - Generate informative error messages in the case of failure
1565 */
f7b0a987
MH
1566static int lock_raw_ref(struct files_ref_store *refs,
1567 const char *refname, int mustexist,
92b1551b
MH
1568 const struct string_list *extras,
1569 const struct string_list *skip,
1570 struct ref_lock **lock_p,
1571 struct strbuf *referent,
1572 unsigned int *type,
1573 struct strbuf *err)
1574{
1575 struct ref_lock *lock;
1576 struct strbuf ref_file = STRBUF_INIT;
1577 int attempts_remaining = 3;
1578 int ret = TRANSACTION_GENERIC_ERROR;
1579
1580 assert(err);
32c597e7 1581 files_assert_main_repository(refs, "lock_raw_ref");
f7b0a987 1582
92b1551b
MH
1583 *type = 0;
1584
1585 /* First lock the file so it can't change out from under us. */
1586
1587 *lock_p = lock = xcalloc(1, sizeof(*lock));
1588
1589 lock->ref_name = xstrdup(refname);
19e02f4f 1590 files_ref_path(refs, &ref_file, refname);
92b1551b
MH
1591
1592retry:
1593 switch (safe_create_leading_directories(ref_file.buf)) {
1594 case SCLD_OK:
1595 break; /* success */
1596 case SCLD_EXISTS:
1597 /*
1598 * Suppose refname is "refs/foo/bar". We just failed
1599 * to create the containing directory, "refs/foo",
1600 * because there was a non-directory in the way. This
1601 * indicates a D/F conflict, probably because of
1602 * another reference such as "refs/foo". There is no
1603 * reason to expect this error to be transitory.
1604 */
1605 if (verify_refname_available(refname, extras, skip, err)) {
1606 if (mustexist) {
1607 /*
1608 * To the user the relevant error is
1609 * that the "mustexist" reference is
1610 * missing:
1611 */
1612 strbuf_reset(err);
1613 strbuf_addf(err, "unable to resolve reference '%s'",
1614 refname);
1615 } else {
1616 /*
1617 * The error message set by
1618 * verify_refname_available_dir() is OK.
1619 */
1620 ret = TRANSACTION_NAME_CONFLICT;
1621 }
1622 } else {
1623 /*
1624 * The file that is in the way isn't a loose
1625 * reference. Report it as a low-level
1626 * failure.
1627 */
1628 strbuf_addf(err, "unable to create lock file %s.lock; "
1629 "non-directory in the way",
1630 ref_file.buf);
1631 }
1632 goto error_return;
1633 case SCLD_VANISHED:
1634 /* Maybe another process was tidying up. Try again. */
1635 if (--attempts_remaining > 0)
1636 goto retry;
1637 /* fall through */
1638 default:
1639 strbuf_addf(err, "unable to create directory for %s",
1640 ref_file.buf);
1641 goto error_return;
1642 }
1643
1644 if (!lock->lk)
1645 lock->lk = xcalloc(1, sizeof(struct lock_file));
1646
1647 if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
1648 if (errno == ENOENT && --attempts_remaining > 0) {
1649 /*
1650 * Maybe somebody just deleted one of the
1651 * directories leading to ref_file. Try
1652 * again:
1653 */
1654 goto retry;
1655 } else {
1656 unable_to_lock_message(ref_file.buf, errno, err);
1657 goto error_return;
1658 }
1659 }
1660
1661 /*
1662 * Now we hold the lock and can read the reference without
1663 * fear that its value will change.
1664 */
1665
f7b0a987 1666 if (files_read_raw_ref(&refs->base, refname,
e1e33b72 1667 lock->old_oid.hash, referent, type)) {
92b1551b
MH
1668 if (errno == ENOENT) {
1669 if (mustexist) {
1670 /* Garden variety missing reference. */
1671 strbuf_addf(err, "unable to resolve reference '%s'",
1672 refname);
1673 goto error_return;
1674 } else {
1675 /*
1676 * Reference is missing, but that's OK. We
1677 * know that there is not a conflict with
1678 * another loose reference because
1679 * (supposing that we are trying to lock
1680 * reference "refs/foo/bar"):
1681 *
1682 * - We were successfully able to create
1683 * the lockfile refs/foo/bar.lock, so we
1684 * know there cannot be a loose reference
1685 * named "refs/foo".
1686 *
1687 * - We got ENOENT and not EISDIR, so we
1688 * know that there cannot be a loose
1689 * reference named "refs/foo/bar/baz".
1690 */
1691 }
1692 } else if (errno == EISDIR) {
1693 /*
1694 * There is a directory in the way. It might have
1695 * contained references that have been deleted. If
1696 * we don't require that the reference already
1697 * exists, try to remove the directory so that it
1698 * doesn't cause trouble when we want to rename the
1699 * lockfile into place later.
1700 */
1701 if (mustexist) {
1702 /* Garden variety missing reference. */
1703 strbuf_addf(err, "unable to resolve reference '%s'",
1704 refname);
1705 goto error_return;
1706 } else if (remove_dir_recursively(&ref_file,
1707 REMOVE_DIR_EMPTY_ONLY)) {
1708 if (verify_refname_available_dir(
1709 refname, extras, skip,
00eebe35 1710 get_loose_refs(refs),
92b1551b
MH
1711 err)) {
1712 /*
1713 * The error message set by
1714 * verify_refname_available() is OK.
1715 */
1716 ret = TRANSACTION_NAME_CONFLICT;
1717 goto error_return;
1718 } else {
1719 /*
1720 * We can't delete the directory,
1721 * but we also don't know of any
1722 * references that it should
1723 * contain.
1724 */
1725 strbuf_addf(err, "there is a non-empty directory '%s' "
1726 "blocking reference '%s'",
1727 ref_file.buf, refname);
1728 goto error_return;
1729 }
1730 }
1731 } else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
1732 strbuf_addf(err, "unable to resolve reference '%s': "
1733 "reference broken", refname);
1734 goto error_return;
1735 } else {
1736 strbuf_addf(err, "unable to resolve reference '%s': %s",
1737 refname, strerror(errno));
1738 goto error_return;
1739 }
1740
1741 /*
1742 * If the ref did not exist and we are creating it,
1743 * make sure there is no existing packed ref whose
1744 * name begins with our refname, nor a packed ref
1745 * whose name is a proper prefix of our refname.
1746 */
1747 if (verify_refname_available_dir(
1748 refname, extras, skip,
00eebe35 1749 get_packed_refs(refs),
92b1551b
MH
1750 err)) {
1751 goto error_return;
1752 }
1753 }
1754
1755 ret = 0;
1756 goto out;
1757
1758error_return:
1759 unlock_ref(lock);
1760 *lock_p = NULL;
1761
1762out:
1763 strbuf_release(&ref_file);
1764 return ret;
1765}
1766
7bd9bcf3
MH
1767/*
1768 * Peel the entry (if possible) and return its new peel_status. If
1769 * repeel is true, re-peel the entry even if there is an old peeled
1770 * value that is already stored in it.
1771 *
1772 * It is OK to call this function with a packed reference entry that
1773 * might be stale and might even refer to an object that has since
1774 * been garbage-collected. In such a case, if the entry has
1775 * REF_KNOWS_PEELED then leave the status unchanged and return
1776 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1777 */
1778static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1779{
1780 enum peel_status status;
1781
1782 if (entry->flag & REF_KNOWS_PEELED) {
1783 if (repeel) {
1784 entry->flag &= ~REF_KNOWS_PEELED;
1785 oidclr(&entry->u.value.peeled);
1786 } else {
1787 return is_null_oid(&entry->u.value.peeled) ?
1788 PEEL_NON_TAG : PEEL_PEELED;
1789 }
1790 }
1791 if (entry->flag & REF_ISBROKEN)
1792 return PEEL_BROKEN;
1793 if (entry->flag & REF_ISSYMREF)
1794 return PEEL_IS_SYMREF;
1795
1796 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1797 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1798 entry->flag |= REF_KNOWS_PEELED;
1799 return status;
1800}
1801
bd427cf2
MH
1802static int files_peel_ref(struct ref_store *ref_store,
1803 const char *refname, unsigned char *sha1)
7bd9bcf3 1804{
bd427cf2 1805 struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
7bd9bcf3
MH
1806 int flag;
1807 unsigned char base[20];
1808
4c4de895
MH
1809 if (current_ref_iter && current_ref_iter->refname == refname) {
1810 struct object_id peeled;
1811
1812 if (ref_iterator_peel(current_ref_iter, &peeled))
7bd9bcf3 1813 return -1;
4c4de895 1814 hashcpy(sha1, peeled.hash);
7bd9bcf3
MH
1815 return 0;
1816 }
1817
1818 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1819 return -1;
1820
1821 /*
1822 * If the reference is packed, read its ref_entry from the
1823 * cache in the hope that we already know its peeled value.
1824 * We only try this optimization on packed references because
1825 * (a) forcing the filling of the loose reference cache could
1826 * be expensive and (b) loose references anyway usually do not
1827 * have REF_KNOWS_PEELED.
1828 */
1829 if (flag & REF_ISPACKED) {
f0d21efc 1830 struct ref_entry *r = get_packed_ref(refs, refname);
7bd9bcf3
MH
1831 if (r) {
1832 if (peel_entry(r, 0))
1833 return -1;
1834 hashcpy(sha1, r->u.value.peeled.hash);
1835 return 0;
1836 }
1837 }
1838
1839 return peel_object(base, sha1);
1840}
1841
3bc581b9
MH
1842struct files_ref_iterator {
1843 struct ref_iterator base;
1844
7bd9bcf3 1845 struct packed_ref_cache *packed_ref_cache;
3bc581b9
MH
1846 struct ref_iterator *iter0;
1847 unsigned int flags;
1848};
7bd9bcf3 1849
3bc581b9
MH
1850static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
1851{
1852 struct files_ref_iterator *iter =
1853 (struct files_ref_iterator *)ref_iterator;
1854 int ok;
7bd9bcf3 1855
3bc581b9 1856 while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
0c09ec07
DT
1857 if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
1858 ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
1859 continue;
1860
3bc581b9
MH
1861 if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
1862 !ref_resolves_to_object(iter->iter0->refname,
1863 iter->iter0->oid,
1864 iter->iter0->flags))
1865 continue;
1866
1867 iter->base.refname = iter->iter0->refname;
1868 iter->base.oid = iter->iter0->oid;
1869 iter->base.flags = iter->iter0->flags;
1870 return ITER_OK;
7bd9bcf3
MH
1871 }
1872
3bc581b9
MH
1873 iter->iter0 = NULL;
1874 if (ref_iterator_abort(ref_iterator) != ITER_DONE)
1875 ok = ITER_ERROR;
1876
1877 return ok;
7bd9bcf3
MH
1878}
1879
3bc581b9
MH
1880static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
1881 struct object_id *peeled)
7bd9bcf3 1882{
3bc581b9
MH
1883 struct files_ref_iterator *iter =
1884 (struct files_ref_iterator *)ref_iterator;
93770590 1885
3bc581b9
MH
1886 return ref_iterator_peel(iter->iter0, peeled);
1887}
1888
1889static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
1890{
1891 struct files_ref_iterator *iter =
1892 (struct files_ref_iterator *)ref_iterator;
1893 int ok = ITER_DONE;
1894
1895 if (iter->iter0)
1896 ok = ref_iterator_abort(iter->iter0);
1897
1898 release_packed_ref_cache(iter->packed_ref_cache);
1899 base_ref_iterator_free(ref_iterator);
1900 return ok;
1901}
1902
1903static struct ref_iterator_vtable files_ref_iterator_vtable = {
1904 files_ref_iterator_advance,
1905 files_ref_iterator_peel,
1906 files_ref_iterator_abort
1907};
1908
1a769003 1909static struct ref_iterator *files_ref_iterator_begin(
37b6f6d5 1910 struct ref_store *ref_store,
3bc581b9
MH
1911 const char *prefix, unsigned int flags)
1912{
00eebe35 1913 struct files_ref_store *refs =
37b6f6d5 1914 files_downcast(ref_store, 1, "ref_iterator_begin");
3bc581b9
MH
1915 struct ref_dir *loose_dir, *packed_dir;
1916 struct ref_iterator *loose_iter, *packed_iter;
1917 struct files_ref_iterator *iter;
1918 struct ref_iterator *ref_iterator;
1919
7bd9bcf3
MH
1920 if (ref_paranoia < 0)
1921 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1922 if (ref_paranoia)
3bc581b9
MH
1923 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1924
1925 iter = xcalloc(1, sizeof(*iter));
1926 ref_iterator = &iter->base;
1927 base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
1928
1929 /*
1930 * We must make sure that all loose refs are read before
1931 * accessing the packed-refs file; this avoids a race
1932 * condition if loose refs are migrated to the packed-refs
1933 * file by a simultaneous process, but our in-memory view is
1934 * from before the migration. We ensure this as follows:
1935 * First, we call prime_ref_dir(), which pre-reads the loose
1936 * references for the subtree into the cache. (If they've
1937 * already been read, that's OK; we only need to guarantee
1938 * that they're read before the packed refs, not *how much*
1939 * before.) After that, we call get_packed_ref_cache(), which
1940 * internally checks whether the packed-ref cache is up to
1941 * date with what is on disk, and re-reads it if not.
1942 */
1943
1944 loose_dir = get_loose_refs(refs);
1945
1946 if (prefix && *prefix)
1947 loose_dir = find_containing_dir(loose_dir, prefix, 0);
7bd9bcf3 1948
3bc581b9
MH
1949 if (loose_dir) {
1950 prime_ref_dir(loose_dir);
1951 loose_iter = cache_ref_iterator_begin(loose_dir);
1952 } else {
1953 /* There's nothing to iterate over. */
1954 loose_iter = empty_ref_iterator_begin();
1955 }
1956
1957 iter->packed_ref_cache = get_packed_ref_cache(refs);
1958 acquire_packed_ref_cache(iter->packed_ref_cache);
1959 packed_dir = get_packed_ref_dir(iter->packed_ref_cache);
1960
1961 if (prefix && *prefix)
1962 packed_dir = find_containing_dir(packed_dir, prefix, 0);
1963
1964 if (packed_dir) {
1965 packed_iter = cache_ref_iterator_begin(packed_dir);
1966 } else {
1967 /* There's nothing to iterate over. */
1968 packed_iter = empty_ref_iterator_begin();
1969 }
1970
1971 iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
1972 iter->flags = flags;
1973
1974 return ref_iterator;
7bd9bcf3
MH
1975}
1976
7bd9bcf3
MH
1977/*
1978 * Verify that the reference locked by lock has the value old_sha1.
1979 * Fail if the reference doesn't exist and mustexist is set. Return 0
1980 * on success. On error, write an error message to err, set errno, and
1981 * return a negative value.
1982 */
1983static int verify_lock(struct ref_lock *lock,
1984 const unsigned char *old_sha1, int mustexist,
1985 struct strbuf *err)
1986{
1987 assert(err);
1988
1989 if (read_ref_full(lock->ref_name,
1990 mustexist ? RESOLVE_REF_READING : 0,
1991 lock->old_oid.hash, NULL)) {
6294dcb4
JK
1992 if (old_sha1) {
1993 int save_errno = errno;
0568c8e9 1994 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
6294dcb4
JK
1995 errno = save_errno;
1996 return -1;
1997 } else {
c368dde9 1998 oidclr(&lock->old_oid);
6294dcb4
JK
1999 return 0;
2000 }
7bd9bcf3 2001 }
6294dcb4 2002 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
0568c8e9 2003 strbuf_addf(err, "ref '%s' is at %s but expected %s",
7bd9bcf3 2004 lock->ref_name,
c368dde9 2005 oid_to_hex(&lock->old_oid),
7bd9bcf3
MH
2006 sha1_to_hex(old_sha1));
2007 errno = EBUSY;
2008 return -1;
2009 }
2010 return 0;
2011}
2012
2013static int remove_empty_directories(struct strbuf *path)
2014{
2015 /*
2016 * we want to create a file but there is a directory there;
2017 * if that is an empty directory (or a directory that contains
2018 * only empty directories), remove them.
2019 */
2020 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
2021}
2022
3b5d3c98
MH
2023static int create_reflock(const char *path, void *cb)
2024{
2025 struct lock_file *lk = cb;
2026
2027 return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;
2028}
2029
7bd9bcf3
MH
2030/*
2031 * Locks a ref returning the lock on success and NULL on failure.
2032 * On failure errno is set to something meaningful.
2033 */
7eb27cdf
MH
2034static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
2035 const char *refname,
7bd9bcf3
MH
2036 const unsigned char *old_sha1,
2037 const struct string_list *extras,
2038 const struct string_list *skip,
bcb497d0 2039 unsigned int flags, int *type,
7bd9bcf3
MH
2040 struct strbuf *err)
2041{
2042 struct strbuf ref_file = STRBUF_INIT;
7bd9bcf3
MH
2043 struct ref_lock *lock;
2044 int last_errno = 0;
7bd9bcf3 2045 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
7a418f3a 2046 int resolve_flags = RESOLVE_REF_NO_RECURSE;
7a418f3a 2047 int resolved;
7bd9bcf3 2048
32c597e7 2049 files_assert_main_repository(refs, "lock_ref_sha1_basic");
7bd9bcf3
MH
2050 assert(err);
2051
2052 lock = xcalloc(1, sizeof(struct ref_lock));
2053
2054 if (mustexist)
2055 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 2056 if (flags & REF_DELETING)
7bd9bcf3 2057 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
7bd9bcf3 2058
19e02f4f 2059 files_ref_path(refs, &ref_file, refname);
7a418f3a
MH
2060 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2061 lock->old_oid.hash, type);
2062 if (!resolved && errno == EISDIR) {
7bd9bcf3
MH
2063 /*
2064 * we are trying to lock foo but we used to
2065 * have foo/bar which now does not exist;
2066 * it is normal for the empty directory 'foo'
2067 * to remain.
2068 */
7a418f3a 2069 if (remove_empty_directories(&ref_file)) {
7bd9bcf3 2070 last_errno = errno;
00eebe35
MH
2071 if (!verify_refname_available_dir(
2072 refname, extras, skip,
2073 get_loose_refs(refs), err))
7bd9bcf3 2074 strbuf_addf(err, "there are still refs under '%s'",
7a418f3a 2075 refname);
7bd9bcf3
MH
2076 goto error_return;
2077 }
7a418f3a
MH
2078 resolved = !!resolve_ref_unsafe(refname, resolve_flags,
2079 lock->old_oid.hash, type);
7bd9bcf3 2080 }
7a418f3a 2081 if (!resolved) {
7bd9bcf3
MH
2082 last_errno = errno;
2083 if (last_errno != ENOTDIR ||
00eebe35
MH
2084 !verify_refname_available_dir(
2085 refname, extras, skip,
2086 get_loose_refs(refs), err))
0568c8e9 2087 strbuf_addf(err, "unable to resolve reference '%s': %s",
7a418f3a 2088 refname, strerror(last_errno));
7bd9bcf3
MH
2089
2090 goto error_return;
2091 }
2859dcd4 2092
7bd9bcf3
MH
2093 /*
2094 * If the ref did not exist and we are creating it, make sure
2095 * there is no existing packed ref whose name begins with our
2096 * refname, nor a packed ref whose name is a proper prefix of
2097 * our refname.
2098 */
2099 if (is_null_oid(&lock->old_oid) &&
2100 verify_refname_available_dir(refname, extras, skip,
00eebe35
MH
2101 get_packed_refs(refs),
2102 err)) {
7bd9bcf3
MH
2103 last_errno = ENOTDIR;
2104 goto error_return;
2105 }
2106
2107 lock->lk = xcalloc(1, sizeof(struct lock_file));
2108
7bd9bcf3 2109 lock->ref_name = xstrdup(refname);
7bd9bcf3 2110
3b5d3c98 2111 if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
7bd9bcf3 2112 last_errno = errno;
3b5d3c98 2113 unable_to_lock_message(ref_file.buf, errno, err);
7bd9bcf3
MH
2114 goto error_return;
2115 }
2116
6294dcb4 2117 if (verify_lock(lock, old_sha1, mustexist, err)) {
7bd9bcf3
MH
2118 last_errno = errno;
2119 goto error_return;
2120 }
2121 goto out;
2122
2123 error_return:
2124 unlock_ref(lock);
2125 lock = NULL;
2126
2127 out:
2128 strbuf_release(&ref_file);
7bd9bcf3
MH
2129 errno = last_errno;
2130 return lock;
2131}
2132
2133/*
2134 * Write an entry to the packed-refs file for the specified refname.
2135 * If peeled is non-NULL, write it as the entry's peeled value.
2136 */
2137static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2138 unsigned char *peeled)
2139{
2140 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2141 if (peeled)
2142 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2143}
2144
2145/*
2146 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2147 */
2148static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2149{
2150 enum peel_status peel_status = peel_entry(entry, 0);
2151
2152 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2153 error("internal error: %s is not a valid packed reference!",
2154 entry->name);
2155 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2156 peel_status == PEEL_PEELED ?
2157 entry->u.value.peeled.hash : NULL);
2158 return 0;
2159}
2160
2161/*
2162 * Lock the packed-refs file for writing. Flags is passed to
2163 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2164 * errno appropriately and return a nonzero value.
2165 */
49c0df6a 2166static int lock_packed_refs(struct files_ref_store *refs, int flags)
7bd9bcf3
MH
2167{
2168 static int timeout_configured = 0;
2169 static int timeout_value = 1000;
7bd9bcf3
MH
2170 struct packed_ref_cache *packed_ref_cache;
2171
32c597e7 2172 files_assert_main_repository(refs, "lock_packed_refs");
49c0df6a 2173
7bd9bcf3
MH
2174 if (!timeout_configured) {
2175 git_config_get_int("core.packedrefstimeout", &timeout_value);
2176 timeout_configured = 1;
2177 }
2178
2179 if (hold_lock_file_for_update_timeout(
33dfb9f3 2180 &packlock, files_packed_refs_path(refs),
7bd9bcf3
MH
2181 flags, timeout_value) < 0)
2182 return -1;
2183 /*
2184 * Get the current packed-refs while holding the lock. If the
2185 * packed-refs file has been modified since we last read it,
2186 * this will automatically invalidate the cache and re-read
2187 * the packed-refs file.
2188 */
00eebe35 2189 packed_ref_cache = get_packed_ref_cache(refs);
7bd9bcf3
MH
2190 packed_ref_cache->lock = &packlock;
2191 /* Increment the reference count to prevent it from being freed: */
2192 acquire_packed_ref_cache(packed_ref_cache);
2193 return 0;
2194}
2195
2196/*
2197 * Write the current version of the packed refs cache from memory to
2198 * disk. The packed-refs file must already be locked for writing (see
2199 * lock_packed_refs()). Return zero on success. On errors, set errno
2200 * and return a nonzero value
2201 */
49c0df6a 2202static int commit_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2203{
2204 struct packed_ref_cache *packed_ref_cache =
00eebe35 2205 get_packed_ref_cache(refs);
7bd9bcf3
MH
2206 int error = 0;
2207 int save_errno = 0;
2208 FILE *out;
2209
32c597e7 2210 files_assert_main_repository(refs, "commit_packed_refs");
49c0df6a 2211
7bd9bcf3
MH
2212 if (!packed_ref_cache->lock)
2213 die("internal error: packed-refs not locked");
2214
2215 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2216 if (!out)
2217 die_errno("unable to fdopen packed-refs descriptor");
2218
2219 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2220 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2221 0, write_packed_entry_fn, out);
2222
2223 if (commit_lock_file(packed_ref_cache->lock)) {
2224 save_errno = errno;
2225 error = -1;
2226 }
2227 packed_ref_cache->lock = NULL;
2228 release_packed_ref_cache(packed_ref_cache);
2229 errno = save_errno;
2230 return error;
2231}
2232
2233/*
2234 * Rollback the lockfile for the packed-refs file, and discard the
2235 * in-memory packed reference cache. (The packed-refs file will be
2236 * read anew if it is needed again after this function is called.)
2237 */
49c0df6a 2238static void rollback_packed_refs(struct files_ref_store *refs)
7bd9bcf3
MH
2239{
2240 struct packed_ref_cache *packed_ref_cache =
00eebe35 2241 get_packed_ref_cache(refs);
7bd9bcf3 2242
32c597e7 2243 files_assert_main_repository(refs, "rollback_packed_refs");
7bd9bcf3
MH
2244
2245 if (!packed_ref_cache->lock)
2246 die("internal error: packed-refs not locked");
2247 rollback_lock_file(packed_ref_cache->lock);
2248 packed_ref_cache->lock = NULL;
2249 release_packed_ref_cache(packed_ref_cache);
00eebe35 2250 clear_packed_ref_cache(refs);
7bd9bcf3
MH
2251}
2252
2253struct ref_to_prune {
2254 struct ref_to_prune *next;
2255 unsigned char sha1[20];
2256 char name[FLEX_ARRAY];
2257};
2258
2259struct pack_refs_cb_data {
2260 unsigned int flags;
2261 struct ref_dir *packed_refs;
2262 struct ref_to_prune *ref_to_prune;
2263};
2264
2265/*
2266 * An each_ref_entry_fn that is run over loose references only. If
2267 * the loose reference can be packed, add an entry in the packed ref
2268 * cache. If the reference should be pruned, also add it to
2269 * ref_to_prune in the pack_refs_cb_data.
2270 */
2271static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2272{
2273 struct pack_refs_cb_data *cb = cb_data;
2274 enum peel_status peel_status;
2275 struct ref_entry *packed_entry;
2276 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2277
2278 /* Do not pack per-worktree refs: */
2279 if (ref_type(entry->name) != REF_TYPE_NORMAL)
2280 return 0;
2281
2282 /* ALWAYS pack tags */
2283 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2284 return 0;
2285
2286 /* Do not pack symbolic or broken refs: */
ffeef642 2287 if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))
7bd9bcf3
MH
2288 return 0;
2289
2290 /* Add a packed ref cache entry equivalent to the loose entry. */
2291 peel_status = peel_entry(entry, 1);
2292 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2293 die("internal error peeling reference %s (%s)",
2294 entry->name, oid_to_hex(&entry->u.value.oid));
2295 packed_entry = find_ref(cb->packed_refs, entry->name);
2296 if (packed_entry) {
2297 /* Overwrite existing packed entry with info from loose entry */
2298 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2299 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2300 } else {
2301 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2302 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2303 add_ref(cb->packed_refs, packed_entry);
2304 }
2305 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2306
2307 /* Schedule the loose reference for pruning if requested. */
2308 if ((cb->flags & PACK_REFS_PRUNE)) {
96ffc06f
JK
2309 struct ref_to_prune *n;
2310 FLEX_ALLOC_STR(n, name, entry->name);
7bd9bcf3 2311 hashcpy(n->sha1, entry->u.value.oid.hash);
7bd9bcf3
MH
2312 n->next = cb->ref_to_prune;
2313 cb->ref_to_prune = n;
2314 }
2315 return 0;
2316}
2317
a8f0db2d
MH
2318enum {
2319 REMOVE_EMPTY_PARENTS_REF = 0x01,
2320 REMOVE_EMPTY_PARENTS_REFLOG = 0x02
2321};
2322
7bd9bcf3 2323/*
a8f0db2d
MH
2324 * Remove empty parent directories associated with the specified
2325 * reference and/or its reflog, but spare [logs/]refs/ and immediate
2326 * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
2327 * REMOVE_EMPTY_PARENTS_REFLOG.
7bd9bcf3 2328 */
802de3da
NTND
2329static void try_remove_empty_parents(struct files_ref_store *refs,
2330 const char *refname,
2331 unsigned int flags)
7bd9bcf3 2332{
8bdaecb4 2333 struct strbuf buf = STRBUF_INIT;
e9dcc305 2334 struct strbuf sb = STRBUF_INIT;
7bd9bcf3
MH
2335 char *p, *q;
2336 int i;
8bdaecb4
MH
2337
2338 strbuf_addstr(&buf, refname);
2339 p = buf.buf;
7bd9bcf3
MH
2340 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2341 while (*p && *p != '/')
2342 p++;
2343 /* tolerate duplicate slashes; see check_refname_format() */
2344 while (*p == '/')
2345 p++;
2346 }
8bdaecb4 2347 q = buf.buf + buf.len;
a8f0db2d 2348 while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
7bd9bcf3
MH
2349 while (q > p && *q != '/')
2350 q--;
2351 while (q > p && *(q-1) == '/')
2352 q--;
2353 if (q == p)
2354 break;
8bdaecb4 2355 strbuf_setlen(&buf, q - buf.buf);
e9dcc305
NTND
2356
2357 strbuf_reset(&sb);
19e02f4f 2358 files_ref_path(refs, &sb, buf.buf);
e9dcc305 2359 if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
a8f0db2d 2360 flags &= ~REMOVE_EMPTY_PARENTS_REF;
e9dcc305
NTND
2361
2362 strbuf_reset(&sb);
802de3da 2363 files_reflog_path(refs, &sb, buf.buf);
e9dcc305 2364 if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
a8f0db2d 2365 flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
7bd9bcf3 2366 }
8bdaecb4 2367 strbuf_release(&buf);
e9dcc305 2368 strbuf_release(&sb);
7bd9bcf3
MH
2369}
2370
2371/* make sure nobody touched the ref, and unlink */
2372static void prune_ref(struct ref_to_prune *r)
2373{
2374 struct ref_transaction *transaction;
2375 struct strbuf err = STRBUF_INIT;
2376
2377 if (check_refname_format(r->name, 0))
2378 return;
2379
2380 transaction = ref_transaction_begin(&err);
2381 if (!transaction ||
2382 ref_transaction_delete(transaction, r->name, r->sha1,
c52ce248 2383 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
7bd9bcf3
MH
2384 ref_transaction_commit(transaction, &err)) {
2385 ref_transaction_free(transaction);
2386 error("%s", err.buf);
2387 strbuf_release(&err);
2388 return;
2389 }
2390 ref_transaction_free(transaction);
2391 strbuf_release(&err);
7bd9bcf3
MH
2392}
2393
2394static void prune_refs(struct ref_to_prune *r)
2395{
2396 while (r) {
2397 prune_ref(r);
2398 r = r->next;
2399 }
2400}
2401
8231527e 2402static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
7bd9bcf3 2403{
00eebe35 2404 struct files_ref_store *refs =
8231527e 2405 files_downcast(ref_store, 0, "pack_refs");
7bd9bcf3
MH
2406 struct pack_refs_cb_data cbdata;
2407
2408 memset(&cbdata, 0, sizeof(cbdata));
2409 cbdata.flags = flags;
2410
49c0df6a 2411 lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
00eebe35 2412 cbdata.packed_refs = get_packed_refs(refs);
7bd9bcf3 2413
00eebe35 2414 do_for_each_entry_in_dir(get_loose_refs(refs), 0,
7bd9bcf3
MH
2415 pack_if_possible_fn, &cbdata);
2416
49c0df6a 2417 if (commit_packed_refs(refs))
7bd9bcf3
MH
2418 die_errno("unable to overwrite old ref-pack file");
2419
2420 prune_refs(cbdata.ref_to_prune);
2421 return 0;
2422}
2423
2424/*
2425 * Rewrite the packed-refs file, omitting any refs listed in
2426 * 'refnames'. On error, leave packed-refs unchanged, write an error
2427 * message to 'err', and return a nonzero value.
2428 *
2429 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2430 */
0a95ac5f
MH
2431static int repack_without_refs(struct files_ref_store *refs,
2432 struct string_list *refnames, struct strbuf *err)
7bd9bcf3
MH
2433{
2434 struct ref_dir *packed;
2435 struct string_list_item *refname;
2436 int ret, needs_repacking = 0, removed = 0;
2437
32c597e7 2438 files_assert_main_repository(refs, "repack_without_refs");
7bd9bcf3
MH
2439 assert(err);
2440
2441 /* Look for a packed ref */
2442 for_each_string_list_item(refname, refnames) {
f0d21efc 2443 if (get_packed_ref(refs, refname->string)) {
7bd9bcf3
MH
2444 needs_repacking = 1;
2445 break;
2446 }
2447 }
2448
2449 /* Avoid locking if we have nothing to do */
2450 if (!needs_repacking)
2451 return 0; /* no refname exists in packed refs */
2452
49c0df6a 2453 if (lock_packed_refs(refs, 0)) {
33dfb9f3 2454 unable_to_lock_message(files_packed_refs_path(refs), errno, err);
7bd9bcf3
MH
2455 return -1;
2456 }
00eebe35 2457 packed = get_packed_refs(refs);
7bd9bcf3
MH
2458
2459 /* Remove refnames from the cache */
2460 for_each_string_list_item(refname, refnames)
2461 if (remove_entry(packed, refname->string) != -1)
2462 removed = 1;
2463 if (!removed) {
2464 /*
2465 * All packed entries disappeared while we were
2466 * acquiring the lock.
2467 */
49c0df6a 2468 rollback_packed_refs(refs);
7bd9bcf3
MH
2469 return 0;
2470 }
2471
2472 /* Write what remains */
49c0df6a 2473 ret = commit_packed_refs(refs);
7bd9bcf3
MH
2474 if (ret)
2475 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2476 strerror(errno));
2477 return ret;
2478}
2479
a27dcf89
DT
2480static int files_delete_refs(struct ref_store *ref_store,
2481 struct string_list *refnames, unsigned int flags)
7bd9bcf3 2482{
0a95ac5f 2483 struct files_ref_store *refs =
a27dcf89 2484 files_downcast(ref_store, 0, "delete_refs");
7bd9bcf3
MH
2485 struct strbuf err = STRBUF_INIT;
2486 int i, result = 0;
2487
2488 if (!refnames->nr)
2489 return 0;
2490
0a95ac5f 2491 result = repack_without_refs(refs, refnames, &err);
7bd9bcf3
MH
2492 if (result) {
2493 /*
2494 * If we failed to rewrite the packed-refs file, then
2495 * it is unsafe to try to remove loose refs, because
2496 * doing so might expose an obsolete packed value for
2497 * a reference that might even point at an object that
2498 * has been garbage collected.
2499 */
2500 if (refnames->nr == 1)
2501 error(_("could not delete reference %s: %s"),
2502 refnames->items[0].string, err.buf);
2503 else
2504 error(_("could not delete references: %s"), err.buf);
2505
2506 goto out;
2507 }
2508
2509 for (i = 0; i < refnames->nr; i++) {
2510 const char *refname = refnames->items[i].string;
2511
755b49ae 2512 if (delete_ref(NULL, refname, NULL, flags))
7bd9bcf3
MH
2513 result |= error(_("could not remove reference %s"), refname);
2514 }
2515
2516out:
2517 strbuf_release(&err);
2518 return result;
2519}
2520
2521/*
2522 * People using contrib's git-new-workdir have .git/logs/refs ->
2523 * /some/other/path/.git/logs/refs, and that may live on another device.
2524 *
2525 * IOW, to avoid cross device rename errors, the temporary renamed log must
2526 * live into logs/refs.
2527 */
a5c1efd6 2528#define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
7bd9bcf3 2529
e9dcc305
NTND
2530struct rename_cb {
2531 const char *tmp_renamed_log;
2532 int true_errno;
2533};
2534
2535static int rename_tmp_log_callback(const char *path, void *cb_data)
7bd9bcf3 2536{
e9dcc305 2537 struct rename_cb *cb = cb_data;
7bd9bcf3 2538
e9dcc305 2539 if (rename(cb->tmp_renamed_log, path)) {
6a7f3631
MH
2540 /*
2541 * rename(a, b) when b is an existing directory ought
2542 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
2543 * Sheesh. Record the true errno for error reporting,
2544 * but report EISDIR to raceproof_create_file() so
2545 * that it knows to retry.
2546 */
e9dcc305 2547 cb->true_errno = errno;
6a7f3631
MH
2548 if (errno == ENOTDIR)
2549 errno = EISDIR;
2550 return -1;
2551 } else {
2552 return 0;
7bd9bcf3 2553 }
6a7f3631 2554}
7bd9bcf3 2555
802de3da 2556static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
6a7f3631 2557{
e9dcc305
NTND
2558 struct strbuf path = STRBUF_INIT;
2559 struct strbuf tmp = STRBUF_INIT;
2560 struct rename_cb cb;
2561 int ret;
6a7f3631 2562
802de3da
NTND
2563 files_reflog_path(refs, &path, newrefname);
2564 files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
e9dcc305
NTND
2565 cb.tmp_renamed_log = tmp.buf;
2566 ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
6a7f3631
MH
2567 if (ret) {
2568 if (errno == EISDIR)
e9dcc305 2569 error("directory not empty: %s", path.buf);
6a7f3631 2570 else
990c98d2 2571 error("unable to move logfile %s to %s: %s",
e9dcc305
NTND
2572 tmp.buf, path.buf,
2573 strerror(cb.true_errno));
7bd9bcf3 2574 }
6a7f3631 2575
e9dcc305
NTND
2576 strbuf_release(&path);
2577 strbuf_release(&tmp);
7bd9bcf3
MH
2578 return ret;
2579}
2580
62665823
MH
2581static int files_verify_refname_available(struct ref_store *ref_store,
2582 const char *newname,
2583 const struct string_list *extras,
2584 const struct string_list *skip,
2585 struct strbuf *err)
7bd9bcf3 2586{
00eebe35 2587 struct files_ref_store *refs =
62665823 2588 files_downcast(ref_store, 1, "verify_refname_available");
00eebe35
MH
2589 struct ref_dir *packed_refs = get_packed_refs(refs);
2590 struct ref_dir *loose_refs = get_loose_refs(refs);
7bd9bcf3
MH
2591
2592 if (verify_refname_available_dir(newname, extras, skip,
2593 packed_refs, err) ||
2594 verify_refname_available_dir(newname, extras, skip,
2595 loose_refs, err))
2596 return -1;
2597
2598 return 0;
2599}
2600
7bd9bcf3
MH
2601static int write_ref_to_lockfile(struct ref_lock *lock,
2602 const unsigned char *sha1, struct strbuf *err);
f18a7892
MH
2603static int commit_ref_update(struct files_ref_store *refs,
2604 struct ref_lock *lock,
7bd9bcf3 2605 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2606 struct strbuf *err);
7bd9bcf3 2607
9b6b40d9
DT
2608static int files_rename_ref(struct ref_store *ref_store,
2609 const char *oldrefname, const char *newrefname,
2610 const char *logmsg)
7bd9bcf3 2611{
9b6b40d9
DT
2612 struct files_ref_store *refs =
2613 files_downcast(ref_store, 0, "rename_ref");
7bd9bcf3
MH
2614 unsigned char sha1[20], orig_sha1[20];
2615 int flag = 0, logmoved = 0;
2616 struct ref_lock *lock;
2617 struct stat loginfo;
e9dcc305
NTND
2618 struct strbuf sb_oldref = STRBUF_INIT;
2619 struct strbuf sb_newref = STRBUF_INIT;
2620 struct strbuf tmp_renamed_log = STRBUF_INIT;
2621 int log, ret;
7bd9bcf3
MH
2622 struct strbuf err = STRBUF_INIT;
2623
802de3da
NTND
2624 files_reflog_path(refs, &sb_oldref, oldrefname);
2625 files_reflog_path(refs, &sb_newref, newrefname);
2626 files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
e9dcc305
NTND
2627
2628 log = !lstat(sb_oldref.buf, &loginfo);
0a3f07d6
NTND
2629 if (log && S_ISLNK(loginfo.st_mode)) {
2630 ret = error("reflog for %s is a symlink", oldrefname);
2631 goto out;
2632 }
7bd9bcf3 2633
12fd3496 2634 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
0a3f07d6
NTND
2635 orig_sha1, &flag)) {
2636 ret = error("refname %s not found", oldrefname);
2637 goto out;
2638 }
e711b1af 2639
0a3f07d6
NTND
2640 if (flag & REF_ISSYMREF) {
2641 ret = error("refname %s is a symbolic ref, renaming it is not supported",
2642 oldrefname);
2643 goto out;
2644 }
2645 if (!rename_ref_available(oldrefname, newrefname)) {
2646 ret = 1;
2647 goto out;
2648 }
7bd9bcf3 2649
e9dcc305 2650 if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
a5c1efd6 2651 ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
0a3f07d6
NTND
2652 oldrefname, strerror(errno));
2653 goto out;
2654 }
7bd9bcf3 2655
893dbf5b 2656 if (delete_ref(logmsg, oldrefname, orig_sha1, REF_NODEREF)) {
7bd9bcf3
MH
2657 error("unable to delete old %s", oldrefname);
2658 goto rollback;
2659 }
2660
12fd3496
DT
2661 /*
2662 * Since we are doing a shallow lookup, sha1 is not the
2663 * correct value to pass to delete_ref as old_sha1. But that
2664 * doesn't matter, because an old_sha1 check wouldn't add to
2665 * the safety anyway; we want to delete the reference whatever
2666 * its current value.
2667 */
2668 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2669 sha1, NULL) &&
755b49ae 2670 delete_ref(NULL, newrefname, NULL, REF_NODEREF)) {
58364324 2671 if (errno == EISDIR) {
7bd9bcf3
MH
2672 struct strbuf path = STRBUF_INIT;
2673 int result;
2674
19e02f4f 2675 files_ref_path(refs, &path, newrefname);
7bd9bcf3
MH
2676 result = remove_empty_directories(&path);
2677 strbuf_release(&path);
2678
2679 if (result) {
2680 error("Directory not empty: %s", newrefname);
2681 goto rollback;
2682 }
2683 } else {
2684 error("unable to delete existing %s", newrefname);
2685 goto rollback;
2686 }
2687 }
2688
802de3da 2689 if (log && rename_tmp_log(refs, newrefname))
7bd9bcf3
MH
2690 goto rollback;
2691
2692 logmoved = log;
2693
7eb27cdf
MH
2694 lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
2695 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
2696 if (!lock) {
2697 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2698 strbuf_release(&err);
2699 goto rollback;
2700 }
2701 hashcpy(lock->old_oid.hash, orig_sha1);
2702
2703 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 2704 commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {
7bd9bcf3
MH
2705 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
2706 strbuf_release(&err);
2707 goto rollback;
2708 }
2709
0a3f07d6
NTND
2710 ret = 0;
2711 goto out;
7bd9bcf3
MH
2712
2713 rollback:
7eb27cdf
MH
2714 lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
2715 REF_NODEREF, NULL, &err);
7bd9bcf3
MH
2716 if (!lock) {
2717 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2718 strbuf_release(&err);
2719 goto rollbacklog;
2720 }
2721
2722 flag = log_all_ref_updates;
341fb286 2723 log_all_ref_updates = LOG_REFS_NONE;
7bd9bcf3 2724 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
f18a7892 2725 commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {
7bd9bcf3
MH
2726 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
2727 strbuf_release(&err);
2728 }
2729 log_all_ref_updates = flag;
2730
2731 rollbacklog:
e9dcc305 2732 if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
7bd9bcf3
MH
2733 error("unable to restore logfile %s from %s: %s",
2734 oldrefname, newrefname, strerror(errno));
2735 if (!logmoved && log &&
e9dcc305 2736 rename(tmp_renamed_log.buf, sb_oldref.buf))
a5c1efd6 2737 error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
7bd9bcf3 2738 oldrefname, strerror(errno));
0a3f07d6
NTND
2739 ret = 1;
2740 out:
e9dcc305
NTND
2741 strbuf_release(&sb_newref);
2742 strbuf_release(&sb_oldref);
2743 strbuf_release(&tmp_renamed_log);
2744
0a3f07d6 2745 return ret;
7bd9bcf3
MH
2746}
2747
2748static int close_ref(struct ref_lock *lock)
2749{
2750 if (close_lock_file(lock->lk))
2751 return -1;
2752 return 0;
2753}
2754
2755static int commit_ref(struct ref_lock *lock)
2756{
5387c0d8
MH
2757 char *path = get_locked_file_path(lock->lk);
2758 struct stat st;
2759
2760 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
2761 /*
2762 * There is a directory at the path we want to rename
2763 * the lockfile to. Hopefully it is empty; try to
2764 * delete it.
2765 */
2766 size_t len = strlen(path);
2767 struct strbuf sb_path = STRBUF_INIT;
2768
2769 strbuf_attach(&sb_path, path, len, len);
2770
2771 /*
2772 * If this fails, commit_lock_file() will also fail
2773 * and will report the problem.
2774 */
2775 remove_empty_directories(&sb_path);
2776 strbuf_release(&sb_path);
2777 } else {
2778 free(path);
2779 }
2780
7bd9bcf3
MH
2781 if (commit_lock_file(lock->lk))
2782 return -1;
2783 return 0;
2784}
2785
1fb0c809
MH
2786static int open_or_create_logfile(const char *path, void *cb)
2787{
2788 int *fd = cb;
2789
2790 *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
2791 return (*fd < 0) ? -1 : 0;
2792}
2793
7bd9bcf3 2794/*
4533e534
MH
2795 * Create a reflog for a ref. If force_create = 0, only create the
2796 * reflog for certain refs (those for which should_autocreate_reflog
2797 * returns non-zero). Otherwise, create it regardless of the reference
2798 * name. If the logfile already existed or was created, return 0 and
2799 * set *logfd to the file descriptor opened for appending to the file.
2800 * If no logfile exists and we decided not to create one, return 0 and
2801 * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
2802 * return -1.
7bd9bcf3 2803 */
802de3da
NTND
2804static int log_ref_setup(struct files_ref_store *refs,
2805 const char *refname, int force_create,
4533e534 2806 int *logfd, struct strbuf *err)
7bd9bcf3 2807{
802de3da
NTND
2808 struct strbuf logfile_sb = STRBUF_INIT;
2809 char *logfile;
2810
2811 files_reflog_path(refs, &logfile_sb, refname);
2812 logfile = strbuf_detach(&logfile_sb, NULL);
7bd9bcf3 2813
7bd9bcf3 2814 if (force_create || should_autocreate_reflog(refname)) {
4533e534 2815 if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
1fb0c809
MH
2816 if (errno == ENOENT)
2817 strbuf_addf(err, "unable to create directory for '%s': "
4533e534 2818 "%s", logfile, strerror(errno));
1fb0c809
MH
2819 else if (errno == EISDIR)
2820 strbuf_addf(err, "there are still logs under '%s'",
4533e534 2821 logfile);
1fb0c809 2822 else
854bda6b 2823 strbuf_addf(err, "unable to append to '%s': %s",
4533e534 2824 logfile, strerror(errno));
7bd9bcf3 2825
4533e534 2826 goto error;
7bd9bcf3 2827 }
854bda6b 2828 } else {
4533e534 2829 *logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
e404f459 2830 if (*logfd < 0) {
854bda6b
MH
2831 if (errno == ENOENT || errno == EISDIR) {
2832 /*
2833 * The logfile doesn't already exist,
2834 * but that is not an error; it only
2835 * means that we won't write log
2836 * entries to it.
2837 */
2838 ;
2839 } else {
2840 strbuf_addf(err, "unable to append to '%s': %s",
4533e534
MH
2841 logfile, strerror(errno));
2842 goto error;
854bda6b 2843 }
7bd9bcf3
MH
2844 }
2845 }
2846
e404f459 2847 if (*logfd >= 0)
4533e534 2848 adjust_shared_perm(logfile);
854bda6b 2849
4533e534 2850 free(logfile);
7bd9bcf3 2851 return 0;
7bd9bcf3 2852
4533e534
MH
2853error:
2854 free(logfile);
2855 return -1;
7bd9bcf3 2856}
7bd9bcf3 2857
e3688bd6
DT
2858static int files_create_reflog(struct ref_store *ref_store,
2859 const char *refname, int force_create,
2860 struct strbuf *err)
7bd9bcf3 2861{
802de3da
NTND
2862 struct files_ref_store *refs =
2863 files_downcast(ref_store, 0, "create_reflog");
e404f459 2864 int fd;
7bd9bcf3 2865
802de3da 2866 if (log_ref_setup(refs, refname, force_create, &fd, err))
4533e534
MH
2867 return -1;
2868
e404f459
MH
2869 if (fd >= 0)
2870 close(fd);
4533e534
MH
2871
2872 return 0;
7bd9bcf3
MH
2873}
2874
2875static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2876 const unsigned char *new_sha1,
2877 const char *committer, const char *msg)
2878{
2879 int msglen, written;
2880 unsigned maxlen, len;
2881 char *logrec;
2882
2883 msglen = msg ? strlen(msg) : 0;
2884 maxlen = strlen(committer) + msglen + 100;
2885 logrec = xmalloc(maxlen);
2886 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2887 sha1_to_hex(old_sha1),
2888 sha1_to_hex(new_sha1),
2889 committer);
2890 if (msglen)
2891 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2892
2893 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2894 free(logrec);
2895 if (written != len)
2896 return -1;
2897
2898 return 0;
2899}
2900
802de3da
NTND
2901static int files_log_ref_write(struct files_ref_store *refs,
2902 const char *refname, const unsigned char *old_sha1,
11f8457f
NTND
2903 const unsigned char *new_sha1, const char *msg,
2904 int flags, struct strbuf *err)
7bd9bcf3 2905{
e404f459 2906 int logfd, result;
7bd9bcf3 2907
341fb286
CW
2908 if (log_all_ref_updates == LOG_REFS_UNSET)
2909 log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
7bd9bcf3 2910
802de3da
NTND
2911 result = log_ref_setup(refs, refname,
2912 flags & REF_FORCE_CREATE_REFLOG,
4533e534 2913 &logfd, err);
7bd9bcf3
MH
2914
2915 if (result)
2916 return result;
2917
7bd9bcf3
MH
2918 if (logfd < 0)
2919 return 0;
2920 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2921 git_committer_info(0), msg);
2922 if (result) {
e9dcc305 2923 struct strbuf sb = STRBUF_INIT;
87b21e05
MH
2924 int save_errno = errno;
2925
802de3da 2926 files_reflog_path(refs, &sb, refname);
87b21e05 2927 strbuf_addf(err, "unable to append to '%s': %s",
e9dcc305
NTND
2928 sb.buf, strerror(save_errno));
2929 strbuf_release(&sb);
7bd9bcf3
MH
2930 close(logfd);
2931 return -1;
2932 }
2933 if (close(logfd)) {
e9dcc305 2934 struct strbuf sb = STRBUF_INIT;
87b21e05
MH
2935 int save_errno = errno;
2936
802de3da 2937 files_reflog_path(refs, &sb, refname);
87b21e05 2938 strbuf_addf(err, "unable to append to '%s': %s",
e9dcc305
NTND
2939 sb.buf, strerror(save_errno));
2940 strbuf_release(&sb);
7bd9bcf3
MH
2941 return -1;
2942 }
2943 return 0;
2944}
2945
7bd9bcf3
MH
2946/*
2947 * Write sha1 into the open lockfile, then close the lockfile. On
2948 * errors, rollback the lockfile, fill in *err and
2949 * return -1.
2950 */
2951static int write_ref_to_lockfile(struct ref_lock *lock,
2952 const unsigned char *sha1, struct strbuf *err)
2953{
2954 static char term = '\n';
2955 struct object *o;
2956 int fd;
2957
2958 o = parse_object(sha1);
2959 if (!o) {
2960 strbuf_addf(err,
0568c8e9 2961 "trying to write ref '%s' with nonexistent object %s",
7bd9bcf3
MH
2962 lock->ref_name, sha1_to_hex(sha1));
2963 unlock_ref(lock);
2964 return -1;
2965 }
2966 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2967 strbuf_addf(err,
0568c8e9 2968 "trying to write non-commit object %s to branch '%s'",
7bd9bcf3
MH
2969 sha1_to_hex(sha1), lock->ref_name);
2970 unlock_ref(lock);
2971 return -1;
2972 }
2973 fd = get_lock_file_fd(lock->lk);
2974 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
2975 write_in_full(fd, &term, 1) != 1 ||
2976 close_ref(lock) < 0) {
2977 strbuf_addf(err,
0568c8e9 2978 "couldn't write '%s'", get_lock_file_path(lock->lk));
7bd9bcf3
MH
2979 unlock_ref(lock);
2980 return -1;
2981 }
2982 return 0;
2983}
2984
2985/*
2986 * Commit a change to a loose reference that has already been written
2987 * to the loose reference lockfile. Also update the reflogs if
2988 * necessary, using the specified lockmsg (which can be NULL).
2989 */
f18a7892
MH
2990static int commit_ref_update(struct files_ref_store *refs,
2991 struct ref_lock *lock,
7bd9bcf3 2992 const unsigned char *sha1, const char *logmsg,
5d9b2de4 2993 struct strbuf *err)
7bd9bcf3 2994{
32c597e7 2995 files_assert_main_repository(refs, "commit_ref_update");
00eebe35
MH
2996
2997 clear_loose_ref_cache(refs);
802de3da
NTND
2998 if (files_log_ref_write(refs, lock->ref_name,
2999 lock->old_oid.hash, sha1,
81b1b6d4 3000 logmsg, 0, err)) {
7bd9bcf3 3001 char *old_msg = strbuf_detach(err, NULL);
0568c8e9 3002 strbuf_addf(err, "cannot update the ref '%s': %s",
7bd9bcf3
MH
3003 lock->ref_name, old_msg);
3004 free(old_msg);
3005 unlock_ref(lock);
3006 return -1;
3007 }
7a418f3a
MH
3008
3009 if (strcmp(lock->ref_name, "HEAD") != 0) {
7bd9bcf3
MH
3010 /*
3011 * Special hack: If a branch is updated directly and HEAD
3012 * points to it (may happen on the remote side of a push
3013 * for example) then logically the HEAD reflog should be
3014 * updated too.
3015 * A generic solution implies reverse symref information,
3016 * but finding all symrefs pointing to the given branch
3017 * would be rather costly for this rare event (the direct
3018 * update of a branch) to be worth it. So let's cheat and
3019 * check with HEAD only which should cover 99% of all usage
3020 * scenarios (even 100% of the default ones).
3021 */
3022 unsigned char head_sha1[20];
3023 int head_flag;
3024 const char *head_ref;
7a418f3a 3025
7bd9bcf3
MH
3026 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3027 head_sha1, &head_flag);
3028 if (head_ref && (head_flag & REF_ISSYMREF) &&
3029 !strcmp(head_ref, lock->ref_name)) {
3030 struct strbuf log_err = STRBUF_INIT;
802de3da
NTND
3031 if (files_log_ref_write(refs, "HEAD",
3032 lock->old_oid.hash, sha1,
3033 logmsg, 0, &log_err)) {
7bd9bcf3
MH
3034 error("%s", log_err.buf);
3035 strbuf_release(&log_err);
3036 }
3037 }
3038 }
7a418f3a 3039
7bd9bcf3 3040 if (commit_ref(lock)) {
0568c8e9 3041 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
7bd9bcf3
MH
3042 unlock_ref(lock);
3043 return -1;
3044 }
3045
3046 unlock_ref(lock);
3047 return 0;
3048}
3049
370e5ad6 3050static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 3051{
370e5ad6 3052 int ret = -1;
7bd9bcf3 3053#ifndef NO_SYMLINK_HEAD
370e5ad6
JK
3054 char *ref_path = get_locked_file_path(lock->lk);
3055 unlink(ref_path);
3056 ret = symlink(target, ref_path);
3057 free(ref_path);
3058
3059 if (ret)
7bd9bcf3 3060 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 3061#endif
370e5ad6
JK
3062 return ret;
3063}
7bd9bcf3 3064
802de3da
NTND
3065static void update_symref_reflog(struct files_ref_store *refs,
3066 struct ref_lock *lock, const char *refname,
370e5ad6
JK
3067 const char *target, const char *logmsg)
3068{
3069 struct strbuf err = STRBUF_INIT;
3070 unsigned char new_sha1[20];
b9badadd 3071 if (logmsg && !read_ref(target, new_sha1) &&
802de3da
NTND
3072 files_log_ref_write(refs, refname, lock->old_oid.hash,
3073 new_sha1, logmsg, 0, &err)) {
7bd9bcf3
MH
3074 error("%s", err.buf);
3075 strbuf_release(&err);
3076 }
370e5ad6 3077}
7bd9bcf3 3078
802de3da
NTND
3079static int create_symref_locked(struct files_ref_store *refs,
3080 struct ref_lock *lock, const char *refname,
370e5ad6
JK
3081 const char *target, const char *logmsg)
3082{
3083 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
802de3da 3084 update_symref_reflog(refs, lock, refname, target, logmsg);
370e5ad6
JK
3085 return 0;
3086 }
3087
3088 if (!fdopen_lock_file(lock->lk, "w"))
3089 return error("unable to fdopen %s: %s",
3090 lock->lk->tempfile.filename.buf, strerror(errno));
3091
802de3da 3092 update_symref_reflog(refs, lock, refname, target, logmsg);
396da8f7 3093
370e5ad6
JK
3094 /* no error check; commit_ref will check ferror */
3095 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
3096 if (commit_ref(lock) < 0)
3097 return error("unable to write symref for %s: %s", refname,
3098 strerror(errno));
7bd9bcf3
MH
3099 return 0;
3100}
3101
284689ba
MH
3102static int files_create_symref(struct ref_store *ref_store,
3103 const char *refname, const char *target,
3104 const char *logmsg)
370e5ad6 3105{
7eb27cdf
MH
3106 struct files_ref_store *refs =
3107 files_downcast(ref_store, 0, "create_symref");
370e5ad6
JK
3108 struct strbuf err = STRBUF_INIT;
3109 struct ref_lock *lock;
3110 int ret;
3111
7eb27cdf
MH
3112 lock = lock_ref_sha1_basic(refs, refname, NULL,
3113 NULL, NULL, REF_NODEREF, NULL,
370e5ad6
JK
3114 &err);
3115 if (!lock) {
3116 error("%s", err.buf);
3117 strbuf_release(&err);
3118 return -1;
3119 }
3120
802de3da 3121 ret = create_symref_locked(refs, lock, refname, target, logmsg);
370e5ad6
JK
3122 unlock_ref(lock);
3123 return ret;
3124}
3125
39ee4c6c 3126int set_worktree_head_symref(const char *gitdir, const char *target, const char *logmsg)
2233066e 3127{
802de3da
NTND
3128 /*
3129 * FIXME: this obviously will not work well for future refs
3130 * backends. This function needs to die.
3131 */
3132 struct files_ref_store *refs =
3133 files_downcast(get_ref_store(NULL), 0, "set_head_symref");
3134
2233066e
KY
3135 static struct lock_file head_lock;
3136 struct ref_lock *lock;
2233066e
KY
3137 struct strbuf head_path = STRBUF_INIT;
3138 const char *head_rel;
3139 int ret;
3140
3141 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));
3142 if (hold_lock_file_for_update(&head_lock, head_path.buf,
3143 LOCK_NO_DEREF) < 0) {
18eb3a9c
KY
3144 struct strbuf err = STRBUF_INIT;
3145 unable_to_lock_message(head_path.buf, errno, &err);
2233066e
KY
3146 error("%s", err.buf);
3147 strbuf_release(&err);
3148 strbuf_release(&head_path);
3149 return -1;
3150 }
3151
3152 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for
3153 linked trees */
3154 head_rel = remove_leading_path(head_path.buf,
3155 absolute_path(get_git_common_dir()));
3156 /* to make use of create_symref_locked(), initialize ref_lock */
3157 lock = xcalloc(1, sizeof(struct ref_lock));
3158 lock->lk = &head_lock;
3159 lock->ref_name = xstrdup(head_rel);
2233066e 3160
802de3da 3161 ret = create_symref_locked(refs, lock, head_rel, target, logmsg);
2233066e
KY
3162
3163 unlock_ref(lock); /* will free lock */
3164 strbuf_release(&head_path);
3165 return ret;
3166}
3167
e3688bd6
DT
3168static int files_reflog_exists(struct ref_store *ref_store,
3169 const char *refname)
7bd9bcf3 3170{
802de3da
NTND
3171 struct files_ref_store *refs =
3172 files_downcast(ref_store, 0, "reflog_exists");
e9dcc305 3173 struct strbuf sb = STRBUF_INIT;
7bd9bcf3 3174 struct stat st;
e9dcc305 3175 int ret;
7bd9bcf3 3176
802de3da 3177 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3178 ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
3179 strbuf_release(&sb);
3180 return ret;
7bd9bcf3
MH
3181}
3182
e3688bd6
DT
3183static int files_delete_reflog(struct ref_store *ref_store,
3184 const char *refname)
7bd9bcf3 3185{
802de3da
NTND
3186 struct files_ref_store *refs =
3187 files_downcast(ref_store, 0, "delete_reflog");
e9dcc305
NTND
3188 struct strbuf sb = STRBUF_INIT;
3189 int ret;
3190
802de3da 3191 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3192 ret = remove_path(sb.buf);
3193 strbuf_release(&sb);
3194 return ret;
7bd9bcf3
MH
3195}
3196
3197static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3198{
9461d272 3199 struct object_id ooid, noid;
7bd9bcf3
MH
3200 char *email_end, *message;
3201 unsigned long timestamp;
3202 int tz;
43bc3b6c 3203 const char *p = sb->buf;
7bd9bcf3
MH
3204
3205 /* old SP new SP name <email> SP time TAB msg LF */
43bc3b6c 3206 if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
3207 parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
3208 parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
3209 !(email_end = strchr(p, '>')) ||
7bd9bcf3
MH
3210 email_end[1] != ' ' ||
3211 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3212 !message || message[0] != ' ' ||
3213 (message[1] != '+' && message[1] != '-') ||
3214 !isdigit(message[2]) || !isdigit(message[3]) ||
3215 !isdigit(message[4]) || !isdigit(message[5]))
3216 return 0; /* corrupt? */
3217 email_end[1] = '\0';
3218 tz = strtol(message + 1, NULL, 10);
3219 if (message[6] != '\t')
3220 message += 6;
3221 else
3222 message += 7;
43bc3b6c 3223 return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
7bd9bcf3
MH
3224}
3225
3226static char *find_beginning_of_line(char *bob, char *scan)
3227{
3228 while (bob < scan && *(--scan) != '\n')
3229 ; /* keep scanning backwards */
3230 /*
3231 * Return either beginning of the buffer, or LF at the end of
3232 * the previous line.
3233 */
3234 return scan;
3235}
3236
e3688bd6
DT
3237static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
3238 const char *refname,
3239 each_reflog_ent_fn fn,
3240 void *cb_data)
7bd9bcf3 3241{
802de3da
NTND
3242 struct files_ref_store *refs =
3243 files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
7bd9bcf3
MH
3244 struct strbuf sb = STRBUF_INIT;
3245 FILE *logfp;
3246 long pos;
3247 int ret = 0, at_tail = 1;
3248
802de3da 3249 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3250 logfp = fopen(sb.buf, "r");
3251 strbuf_release(&sb);
7bd9bcf3
MH
3252 if (!logfp)
3253 return -1;
3254
3255 /* Jump to the end */
3256 if (fseek(logfp, 0, SEEK_END) < 0)
3257 return error("cannot seek back reflog for %s: %s",
3258 refname, strerror(errno));
3259 pos = ftell(logfp);
3260 while (!ret && 0 < pos) {
3261 int cnt;
3262 size_t nread;
3263 char buf[BUFSIZ];
3264 char *endp, *scanp;
3265
3266 /* Fill next block from the end */
3267 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3268 if (fseek(logfp, pos - cnt, SEEK_SET))
3269 return error("cannot seek back reflog for %s: %s",
3270 refname, strerror(errno));
3271 nread = fread(buf, cnt, 1, logfp);
3272 if (nread != 1)
3273 return error("cannot read %d bytes from reflog for %s: %s",
3274 cnt, refname, strerror(errno));
3275 pos -= cnt;
3276
3277 scanp = endp = buf + cnt;
3278 if (at_tail && scanp[-1] == '\n')
3279 /* Looking at the final LF at the end of the file */
3280 scanp--;
3281 at_tail = 0;
3282
3283 while (buf < scanp) {
3284 /*
3285 * terminating LF of the previous line, or the beginning
3286 * of the buffer.
3287 */
3288 char *bp;
3289
3290 bp = find_beginning_of_line(buf, scanp);
3291
3292 if (*bp == '\n') {
3293 /*
3294 * The newline is the end of the previous line,
3295 * so we know we have complete line starting
3296 * at (bp + 1). Prefix it onto any prior data
3297 * we collected for the line and process it.
3298 */
3299 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3300 scanp = bp;
3301 endp = bp + 1;
3302 ret = show_one_reflog_ent(&sb, fn, cb_data);
3303 strbuf_reset(&sb);
3304 if (ret)
3305 break;
3306 } else if (!pos) {
3307 /*
3308 * We are at the start of the buffer, and the
3309 * start of the file; there is no previous
3310 * line, and we have everything for this one.
3311 * Process it, and we can end the loop.
3312 */
3313 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3314 ret = show_one_reflog_ent(&sb, fn, cb_data);
3315 strbuf_reset(&sb);
3316 break;
3317 }
3318
3319 if (bp == buf) {
3320 /*
3321 * We are at the start of the buffer, and there
3322 * is more file to read backwards. Which means
3323 * we are in the middle of a line. Note that we
3324 * may get here even if *bp was a newline; that
3325 * just means we are at the exact end of the
3326 * previous line, rather than some spot in the
3327 * middle.
3328 *
3329 * Save away what we have to be combined with
3330 * the data from the next read.
3331 */
3332 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3333 break;
3334 }
3335 }
3336
3337 }
3338 if (!ret && sb.len)
3339 die("BUG: reverse reflog parser had leftover data");
3340
3341 fclose(logfp);
3342 strbuf_release(&sb);
3343 return ret;
3344}
3345
e3688bd6
DT
3346static int files_for_each_reflog_ent(struct ref_store *ref_store,
3347 const char *refname,
3348 each_reflog_ent_fn fn, void *cb_data)
7bd9bcf3 3349{
802de3da
NTND
3350 struct files_ref_store *refs =
3351 files_downcast(ref_store, 0, "for_each_reflog_ent");
7bd9bcf3
MH
3352 FILE *logfp;
3353 struct strbuf sb = STRBUF_INIT;
3354 int ret = 0;
3355
802de3da 3356 files_reflog_path(refs, &sb, refname);
e9dcc305
NTND
3357 logfp = fopen(sb.buf, "r");
3358 strbuf_release(&sb);
7bd9bcf3
MH
3359 if (!logfp)
3360 return -1;
3361
3362 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3363 ret = show_one_reflog_ent(&sb, fn, cb_data);
3364 fclose(logfp);
3365 strbuf_release(&sb);
3366 return ret;
3367}
7bd9bcf3 3368
2880d16f
MH
3369struct files_reflog_iterator {
3370 struct ref_iterator base;
7bd9bcf3 3371
2880d16f
MH
3372 struct dir_iterator *dir_iterator;
3373 struct object_id oid;
3374};
7bd9bcf3 3375
2880d16f
MH
3376static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
3377{
3378 struct files_reflog_iterator *iter =
3379 (struct files_reflog_iterator *)ref_iterator;
3380 struct dir_iterator *diter = iter->dir_iterator;
3381 int ok;
3382
3383 while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
3384 int flags;
3385
3386 if (!S_ISREG(diter->st.st_mode))
7bd9bcf3 3387 continue;
2880d16f
MH
3388 if (diter->basename[0] == '.')
3389 continue;
3390 if (ends_with(diter->basename, ".lock"))
7bd9bcf3 3391 continue;
7bd9bcf3 3392
2880d16f
MH
3393 if (read_ref_full(diter->relative_path, 0,
3394 iter->oid.hash, &flags)) {
3395 error("bad ref for %s", diter->path.buf);
3396 continue;
7bd9bcf3 3397 }
2880d16f
MH
3398
3399 iter->base.refname = diter->relative_path;
3400 iter->base.oid = &iter->oid;
3401 iter->base.flags = flags;
3402 return ITER_OK;
7bd9bcf3 3403 }
2880d16f
MH
3404
3405 iter->dir_iterator = NULL;
3406 if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
3407 ok = ITER_ERROR;
3408 return ok;
3409}
3410
3411static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
3412 struct object_id *peeled)
3413{
3414 die("BUG: ref_iterator_peel() called for reflog_iterator");
3415}
3416
3417static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
3418{
3419 struct files_reflog_iterator *iter =
3420 (struct files_reflog_iterator *)ref_iterator;
3421 int ok = ITER_DONE;
3422
3423 if (iter->dir_iterator)
3424 ok = dir_iterator_abort(iter->dir_iterator);
3425
3426 base_ref_iterator_free(ref_iterator);
3427 return ok;
3428}
3429
3430static struct ref_iterator_vtable files_reflog_iterator_vtable = {
3431 files_reflog_iterator_advance,
3432 files_reflog_iterator_peel,
3433 files_reflog_iterator_abort
3434};
3435
e3688bd6 3436static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
2880d16f 3437{
802de3da
NTND
3438 struct files_ref_store *refs =
3439 files_downcast(ref_store, 0, "reflog_iterator_begin");
2880d16f
MH
3440 struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
3441 struct ref_iterator *ref_iterator = &iter->base;
e9dcc305 3442 struct strbuf sb = STRBUF_INIT;
2880d16f
MH
3443
3444 base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
802de3da 3445 files_reflog_path(refs, &sb, NULL);
e9dcc305
NTND
3446 iter->dir_iterator = dir_iterator_begin(sb.buf);
3447 strbuf_release(&sb);
2880d16f 3448 return ref_iterator;
7bd9bcf3
MH
3449}
3450
7bd9bcf3
MH
3451static int ref_update_reject_duplicates(struct string_list *refnames,
3452 struct strbuf *err)
3453{
3454 int i, n = refnames->nr;
3455
3456 assert(err);
3457
3458 for (i = 1; i < n; i++)
3459 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3460 strbuf_addf(err,
0568c8e9 3461 "multiple updates for ref '%s' not allowed.",
7bd9bcf3
MH
3462 refnames->items[i].string);
3463 return 1;
3464 }
3465 return 0;
3466}
3467
165056b2 3468/*
92b1551b
MH
3469 * If update is a direct update of head_ref (the reference pointed to
3470 * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
3471 */
3472static int split_head_update(struct ref_update *update,
3473 struct ref_transaction *transaction,
3474 const char *head_ref,
3475 struct string_list *affected_refnames,
3476 struct strbuf *err)
3477{
3478 struct string_list_item *item;
3479 struct ref_update *new_update;
3480
3481 if ((update->flags & REF_LOG_ONLY) ||
3482 (update->flags & REF_ISPRUNING) ||
3483 (update->flags & REF_UPDATE_VIA_HEAD))
3484 return 0;
3485
3486 if (strcmp(update->refname, head_ref))
3487 return 0;
3488
3489 /*
3490 * First make sure that HEAD is not already in the
3491 * transaction. This insertion is O(N) in the transaction
3492 * size, but it happens at most once per transaction.
3493 */
3494 item = string_list_insert(affected_refnames, "HEAD");
3495 if (item->util) {
3496 /* An entry already existed */
3497 strbuf_addf(err,
3498 "multiple updates for 'HEAD' (including one "
3499 "via its referent '%s') are not allowed",
3500 update->refname);
3501 return TRANSACTION_NAME_CONFLICT;
3502 }
3503
3504 new_update = ref_transaction_add_update(
3505 transaction, "HEAD",
3506 update->flags | REF_LOG_ONLY | REF_NODEREF,
3507 update->new_sha1, update->old_sha1,
3508 update->msg);
3509
3510 item->util = new_update;
3511
3512 return 0;
3513}
3514
3515/*
3516 * update is for a symref that points at referent and doesn't have
3517 * REF_NODEREF set. Split it into two updates:
3518 * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
3519 * - A new, separate update for the referent reference
3520 * Note that the new update will itself be subject to splitting when
3521 * the iteration gets to it.
3522 */
fcc42ea0
MH
3523static int split_symref_update(struct files_ref_store *refs,
3524 struct ref_update *update,
92b1551b
MH
3525 const char *referent,
3526 struct ref_transaction *transaction,
3527 struct string_list *affected_refnames,
3528 struct strbuf *err)
3529{
3530 struct string_list_item *item;
3531 struct ref_update *new_update;
3532 unsigned int new_flags;
3533
3534 /*
3535 * First make sure that referent is not already in the
3536 * transaction. This insertion is O(N) in the transaction
3537 * size, but it happens at most once per symref in a
3538 * transaction.
3539 */
3540 item = string_list_insert(affected_refnames, referent);
3541 if (item->util) {
3542 /* An entry already existed */
3543 strbuf_addf(err,
3544 "multiple updates for '%s' (including one "
3545 "via symref '%s') are not allowed",
3546 referent, update->refname);
3547 return TRANSACTION_NAME_CONFLICT;
3548 }
3549
3550 new_flags = update->flags;
3551 if (!strcmp(update->refname, "HEAD")) {
3552 /*
3553 * Record that the new update came via HEAD, so that
3554 * when we process it, split_head_update() doesn't try
3555 * to add another reflog update for HEAD. Note that
3556 * this bit will be propagated if the new_update
3557 * itself needs to be split.
3558 */
3559 new_flags |= REF_UPDATE_VIA_HEAD;
3560 }
3561
3562 new_update = ref_transaction_add_update(
3563 transaction, referent, new_flags,
3564 update->new_sha1, update->old_sha1,
3565 update->msg);
3566
6e30b2f6
MH
3567 new_update->parent_update = update;
3568
3569 /*
3570 * Change the symbolic ref update to log only. Also, it
3571 * doesn't need to check its old SHA-1 value, as that will be
3572 * done when new_update is processed.
3573 */
92b1551b 3574 update->flags |= REF_LOG_ONLY | REF_NODEREF;
6e30b2f6 3575 update->flags &= ~REF_HAVE_OLD;
92b1551b
MH
3576
3577 item->util = new_update;
3578
3579 return 0;
3580}
3581
6e30b2f6
MH
3582/*
3583 * Return the refname under which update was originally requested.
3584 */
3585static const char *original_update_refname(struct ref_update *update)
3586{
3587 while (update->parent_update)
3588 update = update->parent_update;
3589
3590 return update->refname;
3591}
3592
e3f51039
MH
3593/*
3594 * Check whether the REF_HAVE_OLD and old_oid values stored in update
3595 * are consistent with oid, which is the reference's current value. If
3596 * everything is OK, return 0; otherwise, write an error message to
3597 * err and return -1.
3598 */
3599static int check_old_oid(struct ref_update *update, struct object_id *oid,
3600 struct strbuf *err)
3601{
3602 if (!(update->flags & REF_HAVE_OLD) ||
3603 !hashcmp(oid->hash, update->old_sha1))
3604 return 0;
3605
3606 if (is_null_sha1(update->old_sha1))
3607 strbuf_addf(err, "cannot lock ref '%s': "
3608 "reference already exists",
3609 original_update_refname(update));
3610 else if (is_null_oid(oid))
3611 strbuf_addf(err, "cannot lock ref '%s': "
3612 "reference is missing but expected %s",
3613 original_update_refname(update),
3614 sha1_to_hex(update->old_sha1));
3615 else
3616 strbuf_addf(err, "cannot lock ref '%s': "
3617 "is at %s but expected %s",
3618 original_update_refname(update),
3619 oid_to_hex(oid),
3620 sha1_to_hex(update->old_sha1));
3621
3622 return -1;
3623}
3624
92b1551b
MH
3625/*
3626 * Prepare for carrying out update:
3627 * - Lock the reference referred to by update.
3628 * - Read the reference under lock.
3629 * - Check that its old SHA-1 value (if specified) is correct, and in
3630 * any case record it in update->lock->old_oid for later use when
3631 * writing the reflog.
3632 * - If it is a symref update without REF_NODEREF, split it up into a
3633 * REF_LOG_ONLY update of the symref and add a separate update for
3634 * the referent to transaction.
3635 * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
3636 * update of HEAD.
165056b2 3637 */
b3bbbc5c
MH
3638static int lock_ref_for_update(struct files_ref_store *refs,
3639 struct ref_update *update,
165056b2 3640 struct ref_transaction *transaction,
92b1551b 3641 const char *head_ref,
165056b2
MH
3642 struct string_list *affected_refnames,
3643 struct strbuf *err)
3644{
92b1551b
MH
3645 struct strbuf referent = STRBUF_INIT;
3646 int mustexist = (update->flags & REF_HAVE_OLD) &&
3647 !is_null_sha1(update->old_sha1);
165056b2 3648 int ret;
92b1551b 3649 struct ref_lock *lock;
165056b2 3650
32c597e7 3651 files_assert_main_repository(refs, "lock_ref_for_update");
b3bbbc5c 3652
92b1551b 3653 if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
165056b2 3654 update->flags |= REF_DELETING;
92b1551b
MH
3655
3656 if (head_ref) {
3657 ret = split_head_update(update, transaction, head_ref,
3658 affected_refnames, err);
3659 if (ret)
3660 return ret;
3661 }
3662
f7b0a987 3663 ret = lock_raw_ref(refs, update->refname, mustexist,
92b1551b 3664 affected_refnames, NULL,
7d618264 3665 &lock, &referent,
92b1551b 3666 &update->type, err);
92b1551b 3667 if (ret) {
165056b2
MH
3668 char *reason;
3669
165056b2
MH
3670 reason = strbuf_detach(err, NULL);
3671 strbuf_addf(err, "cannot lock ref '%s': %s",
e3f51039 3672 original_update_refname(update), reason);
165056b2
MH
3673 free(reason);
3674 return ret;
3675 }
92b1551b 3676
7d618264 3677 update->backend_data = lock;
92b1551b 3678
8169d0d0 3679 if (update->type & REF_ISSYMREF) {
6e30b2f6
MH
3680 if (update->flags & REF_NODEREF