Merge branch 'kd/pull-rebase-autostash'
[git.git] / refs.c
blob2db2975e08b7cccd644eab6b4b0ad752e4ec02b3
1 #include "cache.h"
2 #include "lockfile.h"
3 #include "refs.h"
4 #include "object.h"
5 #include "tag.h"
6 #include "dir.h"
7 #include "string-list.h"
9 struct ref_lock {
10 char *ref_name;
11 char *orig_ref_name;
12 struct lock_file *lk;
13 struct object_id old_oid;
17 * How to handle various characters in refnames:
18 * 0: An acceptable character for refs
19 * 1: End-of-component
20 * 2: ., look for a preceding . to reject .. in refs
21 * 3: {, look for a preceding @ to reject @{ in refs
22 * 4: A bad character: ASCII control characters, and
23 * ":", "?", "[", "\", "^", "~", SP, or TAB
24 * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
26 static unsigned char refname_disposition[256] = {
27 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
28 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
29 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
30 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
31 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
32 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
33 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
34 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
38 * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
39 * refs (i.e., because the reference is about to be deleted anyway).
41 #define REF_DELETING 0x02
44 * Used as a flag in ref_update::flags when a loose ref is being
45 * pruned.
47 #define REF_ISPRUNING 0x04
50 * Used as a flag in ref_update::flags when the reference should be
51 * updated to new_sha1.
53 #define REF_HAVE_NEW 0x08
56 * Used as a flag in ref_update::flags when old_sha1 should be
57 * checked.
59 #define REF_HAVE_OLD 0x10
62 * Used as a flag in ref_update::flags when the lockfile needs to be
63 * committed.
65 #define REF_NEEDS_COMMIT 0x20
68 * 0x40 is REF_FORCE_CREATE_REFLOG, so skip it if you're adding a
69 * value to ref_update::flags
73 * Try to read one refname component from the front of refname.
74 * Return the length of the component found, or -1 if the component is
75 * not legal. It is legal if it is something reasonable to have under
76 * ".git/refs/"; We do not like it if:
78 * - any path component of it begins with ".", or
79 * - it has double dots "..", or
80 * - it has ASCII control characters, or
81 * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
82 * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
83 * - it ends with a "/", or
84 * - it ends with ".lock", or
85 * - it contains a "@{" portion
87 static int check_refname_component(const char *refname, int *flags)
89 const char *cp;
90 char last = '\0';
92 for (cp = refname; ; cp++) {
93 int ch = *cp & 255;
94 unsigned char disp = refname_disposition[ch];
95 switch (disp) {
96 case 1:
97 goto out;
98 case 2:
99 if (last == '.')
100 return -1; /* Refname contains "..". */
101 break;
102 case 3:
103 if (last == '@')
104 return -1; /* Refname contains "@{". */
105 break;
106 case 4:
107 return -1;
108 case 5:
109 if (!(*flags & REFNAME_REFSPEC_PATTERN))
110 return -1; /* refspec can't be a pattern */
113 * Unset the pattern flag so that we only accept
114 * a single asterisk for one side of refspec.
116 *flags &= ~ REFNAME_REFSPEC_PATTERN;
117 break;
119 last = ch;
121 out:
122 if (cp == refname)
123 return 0; /* Component has zero length. */
124 if (refname[0] == '.')
125 return -1; /* Component starts with '.'. */
126 if (cp - refname >= LOCK_SUFFIX_LEN &&
127 !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
128 return -1; /* Refname ends with ".lock". */
129 return cp - refname;
132 int check_refname_format(const char *refname, int flags)
134 int component_len, component_count = 0;
136 if (!strcmp(refname, "@"))
137 /* Refname is a single character '@'. */
138 return -1;
140 while (1) {
141 /* We are at the start of a path component. */
142 component_len = check_refname_component(refname, &flags);
143 if (component_len <= 0)
144 return -1;
146 component_count++;
147 if (refname[component_len] == '\0')
148 break;
149 /* Skip to next component. */
150 refname += component_len + 1;
153 if (refname[component_len - 1] == '.')
154 return -1; /* Refname ends with '.'. */
155 if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
156 return -1; /* Refname has only one component. */
157 return 0;
160 struct ref_entry;
163 * Information used (along with the information in ref_entry) to
164 * describe a single cached reference. This data structure only
165 * occurs embedded in a union in struct ref_entry, and only when
166 * (ref_entry->flag & REF_DIR) is zero.
168 struct ref_value {
170 * The name of the object to which this reference resolves
171 * (which may be a tag object). If REF_ISBROKEN, this is
172 * null. If REF_ISSYMREF, then this is the name of the object
173 * referred to by the last reference in the symlink chain.
175 struct object_id oid;
178 * If REF_KNOWS_PEELED, then this field holds the peeled value
179 * of this reference, or null if the reference is known not to
180 * be peelable. See the documentation for peel_ref() for an
181 * exact definition of "peelable".
183 struct object_id peeled;
186 struct ref_cache;
189 * Information used (along with the information in ref_entry) to
190 * describe a level in the hierarchy of references. This data
191 * structure only occurs embedded in a union in struct ref_entry, and
192 * only when (ref_entry.flag & REF_DIR) is set. In that case,
193 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
194 * in the directory have already been read:
196 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
197 * or packed references, already read.
199 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
200 * references that hasn't been read yet (nor has any of its
201 * subdirectories).
203 * Entries within a directory are stored within a growable array of
204 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
205 * sorted are sorted by their component name in strcmp() order and the
206 * remaining entries are unsorted.
208 * Loose references are read lazily, one directory at a time. When a
209 * directory of loose references is read, then all of the references
210 * in that directory are stored, and REF_INCOMPLETE stubs are created
211 * for any subdirectories, but the subdirectories themselves are not
212 * read. The reading is triggered by get_ref_dir().
214 struct ref_dir {
215 int nr, alloc;
218 * Entries with index 0 <= i < sorted are sorted by name. New
219 * entries are appended to the list unsorted, and are sorted
220 * only when required; thus we avoid the need to sort the list
221 * after the addition of every reference.
223 int sorted;
225 /* A pointer to the ref_cache that contains this ref_dir. */
226 struct ref_cache *ref_cache;
228 struct ref_entry **entries;
232 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
233 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
234 * public values; see refs.h.
238 * The field ref_entry->u.value.peeled of this value entry contains
239 * the correct peeled value for the reference, which might be
240 * null_sha1 if the reference is not a tag or if it is broken.
242 #define REF_KNOWS_PEELED 0x10
244 /* ref_entry represents a directory of references */
245 #define REF_DIR 0x20
248 * Entry has not yet been read from disk (used only for REF_DIR
249 * entries representing loose references)
251 #define REF_INCOMPLETE 0x40
254 * A ref_entry represents either a reference or a "subdirectory" of
255 * references.
257 * Each directory in the reference namespace is represented by a
258 * ref_entry with (flags & REF_DIR) set and containing a subdir member
259 * that holds the entries in that directory that have been read so
260 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
261 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
262 * used for loose reference directories.
264 * References are represented by a ref_entry with (flags & REF_DIR)
265 * unset and a value member that describes the reference's value. The
266 * flag member is at the ref_entry level, but it is also needed to
267 * interpret the contents of the value field (in other words, a
268 * ref_value object is not very much use without the enclosing
269 * ref_entry).
271 * Reference names cannot end with slash and directories' names are
272 * always stored with a trailing slash (except for the top-level
273 * directory, which is always denoted by ""). This has two nice
274 * consequences: (1) when the entries in each subdir are sorted
275 * lexicographically by name (as they usually are), the references in
276 * a whole tree can be generated in lexicographic order by traversing
277 * the tree in left-to-right, depth-first order; (2) the names of
278 * references and subdirectories cannot conflict, and therefore the
279 * presence of an empty subdirectory does not block the creation of a
280 * similarly-named reference. (The fact that reference names with the
281 * same leading components can conflict *with each other* is a
282 * separate issue that is regulated by verify_refname_available().)
284 * Please note that the name field contains the fully-qualified
285 * reference (or subdirectory) name. Space could be saved by only
286 * storing the relative names. But that would require the full names
287 * to be generated on the fly when iterating in do_for_each_ref(), and
288 * would break callback functions, who have always been able to assume
289 * that the name strings that they are passed will not be freed during
290 * the iteration.
292 struct ref_entry {
293 unsigned char flag; /* ISSYMREF? ISPACKED? */
294 union {
295 struct ref_value value; /* if not (flags&REF_DIR) */
296 struct ref_dir subdir; /* if (flags&REF_DIR) */
297 } u;
299 * The full name of the reference (e.g., "refs/heads/master")
300 * or the full name of the directory with a trailing slash
301 * (e.g., "refs/heads/"):
303 char name[FLEX_ARRAY];
306 static void read_loose_refs(const char *dirname, struct ref_dir *dir);
308 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
310 struct ref_dir *dir;
311 assert(entry->flag & REF_DIR);
312 dir = &entry->u.subdir;
313 if (entry->flag & REF_INCOMPLETE) {
314 read_loose_refs(entry->name, dir);
315 entry->flag &= ~REF_INCOMPLETE;
317 return dir;
321 * Check if a refname is safe.
322 * For refs that start with "refs/" we consider it safe as long they do
323 * not try to resolve to outside of refs/.
325 * For all other refs we only consider them safe iff they only contain
326 * upper case characters and '_' (like "HEAD" AND "MERGE_HEAD", and not like
327 * "config").
329 static int refname_is_safe(const char *refname)
331 if (starts_with(refname, "refs/")) {
332 char *buf;
333 int result;
335 buf = xmalloc(strlen(refname) + 1);
337 * Does the refname try to escape refs/?
338 * For example: refs/foo/../bar is safe but refs/foo/../../bar
339 * is not.
341 result = !normalize_path_copy(buf, refname + strlen("refs/"));
342 free(buf);
343 return result;
345 while (*refname) {
346 if (!isupper(*refname) && *refname != '_')
347 return 0;
348 refname++;
350 return 1;
353 static struct ref_entry *create_ref_entry(const char *refname,
354 const unsigned char *sha1, int flag,
355 int check_name)
357 int len;
358 struct ref_entry *ref;
360 if (check_name &&
361 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
362 die("Reference has invalid format: '%s'", refname);
363 len = strlen(refname) + 1;
364 ref = xmalloc(sizeof(struct ref_entry) + len);
365 hashcpy(ref->u.value.oid.hash, sha1);
366 oidclr(&ref->u.value.peeled);
367 memcpy(ref->name, refname, len);
368 ref->flag = flag;
369 return ref;
372 static void clear_ref_dir(struct ref_dir *dir);
374 static void free_ref_entry(struct ref_entry *entry)
376 if (entry->flag & REF_DIR) {
378 * Do not use get_ref_dir() here, as that might
379 * trigger the reading of loose refs.
381 clear_ref_dir(&entry->u.subdir);
383 free(entry);
387 * Add a ref_entry to the end of dir (unsorted). Entry is always
388 * stored directly in dir; no recursion into subdirectories is
389 * done.
391 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
393 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
394 dir->entries[dir->nr++] = entry;
395 /* optimize for the case that entries are added in order */
396 if (dir->nr == 1 ||
397 (dir->nr == dir->sorted + 1 &&
398 strcmp(dir->entries[dir->nr - 2]->name,
399 dir->entries[dir->nr - 1]->name) < 0))
400 dir->sorted = dir->nr;
404 * Clear and free all entries in dir, recursively.
406 static void clear_ref_dir(struct ref_dir *dir)
408 int i;
409 for (i = 0; i < dir->nr; i++)
410 free_ref_entry(dir->entries[i]);
411 free(dir->entries);
412 dir->sorted = dir->nr = dir->alloc = 0;
413 dir->entries = NULL;
417 * Create a struct ref_entry object for the specified dirname.
418 * dirname is the name of the directory with a trailing slash (e.g.,
419 * "refs/heads/") or "" for the top-level directory.
421 static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
422 const char *dirname, size_t len,
423 int incomplete)
425 struct ref_entry *direntry;
426 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
427 memcpy(direntry->name, dirname, len);
428 direntry->name[len] = '\0';
429 direntry->u.subdir.ref_cache = ref_cache;
430 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
431 return direntry;
434 static int ref_entry_cmp(const void *a, const void *b)
436 struct ref_entry *one = *(struct ref_entry **)a;
437 struct ref_entry *two = *(struct ref_entry **)b;
438 return strcmp(one->name, two->name);
441 static void sort_ref_dir(struct ref_dir *dir);
443 struct string_slice {
444 size_t len;
445 const char *str;
448 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
450 const struct string_slice *key = key_;
451 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
452 int cmp = strncmp(key->str, ent->name, key->len);
453 if (cmp)
454 return cmp;
455 return '\0' - (unsigned char)ent->name[key->len];
459 * Return the index of the entry with the given refname from the
460 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
461 * no such entry is found. dir must already be complete.
463 static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
465 struct ref_entry **r;
466 struct string_slice key;
468 if (refname == NULL || !dir->nr)
469 return -1;
471 sort_ref_dir(dir);
472 key.len = len;
473 key.str = refname;
474 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
475 ref_entry_cmp_sslice);
477 if (r == NULL)
478 return -1;
480 return r - dir->entries;
484 * Search for a directory entry directly within dir (without
485 * recursing). Sort dir if necessary. subdirname must be a directory
486 * name (i.e., end in '/'). If mkdir is set, then create the
487 * directory if it is missing; otherwise, return NULL if the desired
488 * directory cannot be found. dir must already be complete.
490 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
491 const char *subdirname, size_t len,
492 int mkdir)
494 int entry_index = search_ref_dir(dir, subdirname, len);
495 struct ref_entry *entry;
496 if (entry_index == -1) {
497 if (!mkdir)
498 return NULL;
500 * Since dir is complete, the absence of a subdir
501 * means that the subdir really doesn't exist;
502 * therefore, create an empty record for it but mark
503 * the record complete.
505 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
506 add_entry_to_dir(dir, entry);
507 } else {
508 entry = dir->entries[entry_index];
510 return get_ref_dir(entry);
514 * If refname is a reference name, find the ref_dir within the dir
515 * tree that should hold refname. If refname is a directory name
516 * (i.e., ends in '/'), then return that ref_dir itself. dir must
517 * represent the top-level directory and must already be complete.
518 * Sort ref_dirs and recurse into subdirectories as necessary. If
519 * mkdir is set, then create any missing directories; otherwise,
520 * return NULL if the desired directory cannot be found.
522 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
523 const char *refname, int mkdir)
525 const char *slash;
526 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
527 size_t dirnamelen = slash - refname + 1;
528 struct ref_dir *subdir;
529 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
530 if (!subdir) {
531 dir = NULL;
532 break;
534 dir = subdir;
537 return dir;
541 * Find the value entry with the given name in dir, sorting ref_dirs
542 * and recursing into subdirectories as necessary. If the name is not
543 * found or it corresponds to a directory entry, return NULL.
545 static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
547 int entry_index;
548 struct ref_entry *entry;
549 dir = find_containing_dir(dir, refname, 0);
550 if (!dir)
551 return NULL;
552 entry_index = search_ref_dir(dir, refname, strlen(refname));
553 if (entry_index == -1)
554 return NULL;
555 entry = dir->entries[entry_index];
556 return (entry->flag & REF_DIR) ? NULL : entry;
560 * Remove the entry with the given name from dir, recursing into
561 * subdirectories as necessary. If refname is the name of a directory
562 * (i.e., ends with '/'), then remove the directory and its contents.
563 * If the removal was successful, return the number of entries
564 * remaining in the directory entry that contained the deleted entry.
565 * If the name was not found, return -1. Please note that this
566 * function only deletes the entry from the cache; it does not delete
567 * it from the filesystem or ensure that other cache entries (which
568 * might be symbolic references to the removed entry) are updated.
569 * Nor does it remove any containing dir entries that might be made
570 * empty by the removal. dir must represent the top-level directory
571 * and must already be complete.
573 static int remove_entry(struct ref_dir *dir, const char *refname)
575 int refname_len = strlen(refname);
576 int entry_index;
577 struct ref_entry *entry;
578 int is_dir = refname[refname_len - 1] == '/';
579 if (is_dir) {
581 * refname represents a reference directory. Remove
582 * the trailing slash; otherwise we will get the
583 * directory *representing* refname rather than the
584 * one *containing* it.
586 char *dirname = xmemdupz(refname, refname_len - 1);
587 dir = find_containing_dir(dir, dirname, 0);
588 free(dirname);
589 } else {
590 dir = find_containing_dir(dir, refname, 0);
592 if (!dir)
593 return -1;
594 entry_index = search_ref_dir(dir, refname, refname_len);
595 if (entry_index == -1)
596 return -1;
597 entry = dir->entries[entry_index];
599 memmove(&dir->entries[entry_index],
600 &dir->entries[entry_index + 1],
601 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
603 dir->nr--;
604 if (dir->sorted > entry_index)
605 dir->sorted--;
606 free_ref_entry(entry);
607 return dir->nr;
611 * Add a ref_entry to the ref_dir (unsorted), recursing into
612 * subdirectories as necessary. dir must represent the top-level
613 * directory. Return 0 on success.
615 static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
617 dir = find_containing_dir(dir, ref->name, 1);
618 if (!dir)
619 return -1;
620 add_entry_to_dir(dir, ref);
621 return 0;
625 * Emit a warning and return true iff ref1 and ref2 have the same name
626 * and the same sha1. Die if they have the same name but different
627 * sha1s.
629 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
631 if (strcmp(ref1->name, ref2->name))
632 return 0;
634 /* Duplicate name; make sure that they don't conflict: */
636 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
637 /* This is impossible by construction */
638 die("Reference directory conflict: %s", ref1->name);
640 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
641 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
643 warning("Duplicated ref: %s", ref1->name);
644 return 1;
648 * Sort the entries in dir non-recursively (if they are not already
649 * sorted) and remove any duplicate entries.
651 static void sort_ref_dir(struct ref_dir *dir)
653 int i, j;
654 struct ref_entry *last = NULL;
657 * This check also prevents passing a zero-length array to qsort(),
658 * which is a problem on some platforms.
660 if (dir->sorted == dir->nr)
661 return;
663 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
665 /* Remove any duplicates: */
666 for (i = 0, j = 0; j < dir->nr; j++) {
667 struct ref_entry *entry = dir->entries[j];
668 if (last && is_dup_ref(last, entry))
669 free_ref_entry(entry);
670 else
671 last = dir->entries[i++] = entry;
673 dir->sorted = dir->nr = i;
676 /* Include broken references in a do_for_each_ref*() iteration: */
677 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
680 * Return true iff the reference described by entry can be resolved to
681 * an object in the database. Emit a warning if the referred-to
682 * object does not exist.
684 static int ref_resolves_to_object(struct ref_entry *entry)
686 if (entry->flag & REF_ISBROKEN)
687 return 0;
688 if (!has_sha1_file(entry->u.value.oid.hash)) {
689 error("%s does not point to a valid object!", entry->name);
690 return 0;
692 return 1;
696 * current_ref is a performance hack: when iterating over references
697 * using the for_each_ref*() functions, current_ref is set to the
698 * current reference's entry before calling the callback function. If
699 * the callback function calls peel_ref(), then peel_ref() first
700 * checks whether the reference to be peeled is the current reference
701 * (it usually is) and if so, returns that reference's peeled version
702 * if it is available. This avoids a refname lookup in a common case.
704 static struct ref_entry *current_ref;
706 typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
708 struct ref_entry_cb {
709 const char *base;
710 int trim;
711 int flags;
712 each_ref_fn *fn;
713 void *cb_data;
717 * Handle one reference in a do_for_each_ref*()-style iteration,
718 * calling an each_ref_fn for each entry.
720 static int do_one_ref(struct ref_entry *entry, void *cb_data)
722 struct ref_entry_cb *data = cb_data;
723 struct ref_entry *old_current_ref;
724 int retval;
726 if (!starts_with(entry->name, data->base))
727 return 0;
729 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
730 !ref_resolves_to_object(entry))
731 return 0;
733 /* Store the old value, in case this is a recursive call: */
734 old_current_ref = current_ref;
735 current_ref = entry;
736 retval = data->fn(entry->name + data->trim, &entry->u.value.oid,
737 entry->flag, data->cb_data);
738 current_ref = old_current_ref;
739 return retval;
743 * Call fn for each reference in dir that has index in the range
744 * offset <= index < dir->nr. Recurse into subdirectories that are in
745 * that index range, sorting them before iterating. This function
746 * does not sort dir itself; it should be sorted beforehand. fn is
747 * called for all references, including broken ones.
749 static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
750 each_ref_entry_fn fn, void *cb_data)
752 int i;
753 assert(dir->sorted == dir->nr);
754 for (i = offset; i < dir->nr; i++) {
755 struct ref_entry *entry = dir->entries[i];
756 int retval;
757 if (entry->flag & REF_DIR) {
758 struct ref_dir *subdir = get_ref_dir(entry);
759 sort_ref_dir(subdir);
760 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
761 } else {
762 retval = fn(entry, cb_data);
764 if (retval)
765 return retval;
767 return 0;
771 * Call fn for each reference in the union of dir1 and dir2, in order
772 * by refname. Recurse into subdirectories. If a value entry appears
773 * in both dir1 and dir2, then only process the version that is in
774 * dir2. The input dirs must already be sorted, but subdirs will be
775 * sorted as needed. fn is called for all references, including
776 * broken ones.
778 static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
779 struct ref_dir *dir2,
780 each_ref_entry_fn fn, void *cb_data)
782 int retval;
783 int i1 = 0, i2 = 0;
785 assert(dir1->sorted == dir1->nr);
786 assert(dir2->sorted == dir2->nr);
787 while (1) {
788 struct ref_entry *e1, *e2;
789 int cmp;
790 if (i1 == dir1->nr) {
791 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
793 if (i2 == dir2->nr) {
794 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
796 e1 = dir1->entries[i1];
797 e2 = dir2->entries[i2];
798 cmp = strcmp(e1->name, e2->name);
799 if (cmp == 0) {
800 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
801 /* Both are directories; descend them in parallel. */
802 struct ref_dir *subdir1 = get_ref_dir(e1);
803 struct ref_dir *subdir2 = get_ref_dir(e2);
804 sort_ref_dir(subdir1);
805 sort_ref_dir(subdir2);
806 retval = do_for_each_entry_in_dirs(
807 subdir1, subdir2, fn, cb_data);
808 i1++;
809 i2++;
810 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
811 /* Both are references; ignore the one from dir1. */
812 retval = fn(e2, cb_data);
813 i1++;
814 i2++;
815 } else {
816 die("conflict between reference and directory: %s",
817 e1->name);
819 } else {
820 struct ref_entry *e;
821 if (cmp < 0) {
822 e = e1;
823 i1++;
824 } else {
825 e = e2;
826 i2++;
828 if (e->flag & REF_DIR) {
829 struct ref_dir *subdir = get_ref_dir(e);
830 sort_ref_dir(subdir);
831 retval = do_for_each_entry_in_dir(
832 subdir, 0, fn, cb_data);
833 } else {
834 retval = fn(e, cb_data);
837 if (retval)
838 return retval;
843 * Load all of the refs from the dir into our in-memory cache. The hard work
844 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
845 * through all of the sub-directories. We do not even need to care about
846 * sorting, as traversal order does not matter to us.
848 static void prime_ref_dir(struct ref_dir *dir)
850 int i;
851 for (i = 0; i < dir->nr; i++) {
852 struct ref_entry *entry = dir->entries[i];
853 if (entry->flag & REF_DIR)
854 prime_ref_dir(get_ref_dir(entry));
858 struct nonmatching_ref_data {
859 const struct string_list *skip;
860 const char *conflicting_refname;
863 static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
865 struct nonmatching_ref_data *data = vdata;
867 if (data->skip && string_list_has_string(data->skip, entry->name))
868 return 0;
870 data->conflicting_refname = entry->name;
871 return 1;
875 * Return 0 if a reference named refname could be created without
876 * conflicting with the name of an existing reference in dir.
877 * Otherwise, return a negative value and write an explanation to err.
878 * If extras is non-NULL, it is a list of additional refnames with
879 * which refname is not allowed to conflict. If skip is non-NULL,
880 * ignore potential conflicts with refs in skip (e.g., because they
881 * are scheduled for deletion in the same operation). Behavior is
882 * undefined if the same name is listed in both extras and skip.
884 * Two reference names conflict if one of them exactly matches the
885 * leading components of the other; e.g., "refs/foo/bar" conflicts
886 * with both "refs/foo" and with "refs/foo/bar/baz" but not with
887 * "refs/foo/bar" or "refs/foo/barbados".
889 * extras and skip must be sorted.
891 static int verify_refname_available(const char *refname,
892 const struct string_list *extras,
893 const struct string_list *skip,
894 struct ref_dir *dir,
895 struct strbuf *err)
897 const char *slash;
898 int pos;
899 struct strbuf dirname = STRBUF_INIT;
900 int ret = -1;
903 * For the sake of comments in this function, suppose that
904 * refname is "refs/foo/bar".
907 assert(err);
909 strbuf_grow(&dirname, strlen(refname) + 1);
910 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
911 /* Expand dirname to the new prefix, not including the trailing slash: */
912 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
915 * We are still at a leading dir of the refname (e.g.,
916 * "refs/foo"; if there is a reference with that name,
917 * it is a conflict, *unless* it is in skip.
919 if (dir) {
920 pos = search_ref_dir(dir, dirname.buf, dirname.len);
921 if (pos >= 0 &&
922 (!skip || !string_list_has_string(skip, dirname.buf))) {
924 * We found a reference whose name is
925 * a proper prefix of refname; e.g.,
926 * "refs/foo", and is not in skip.
928 strbuf_addf(err, "'%s' exists; cannot create '%s'",
929 dirname.buf, refname);
930 goto cleanup;
934 if (extras && string_list_has_string(extras, dirname.buf) &&
935 (!skip || !string_list_has_string(skip, dirname.buf))) {
936 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
937 refname, dirname.buf);
938 goto cleanup;
942 * Otherwise, we can try to continue our search with
943 * the next component. So try to look up the
944 * directory, e.g., "refs/foo/". If we come up empty,
945 * we know there is nothing under this whole prefix,
946 * but even in that case we still have to continue the
947 * search for conflicts with extras.
949 strbuf_addch(&dirname, '/');
950 if (dir) {
951 pos = search_ref_dir(dir, dirname.buf, dirname.len);
952 if (pos < 0) {
954 * There was no directory "refs/foo/",
955 * so there is nothing under this
956 * whole prefix. So there is no need
957 * to continue looking for conflicting
958 * references. But we need to continue
959 * looking for conflicting extras.
961 dir = NULL;
962 } else {
963 dir = get_ref_dir(dir->entries[pos]);
969 * We are at the leaf of our refname (e.g., "refs/foo/bar").
970 * There is no point in searching for a reference with that
971 * name, because a refname isn't considered to conflict with
972 * itself. But we still need to check for references whose
973 * names are in the "refs/foo/bar/" namespace, because they
974 * *do* conflict.
976 strbuf_addstr(&dirname, refname + dirname.len);
977 strbuf_addch(&dirname, '/');
979 if (dir) {
980 pos = search_ref_dir(dir, dirname.buf, dirname.len);
982 if (pos >= 0) {
984 * We found a directory named "$refname/"
985 * (e.g., "refs/foo/bar/"). It is a problem
986 * iff it contains any ref that is not in
987 * "skip".
989 struct nonmatching_ref_data data;
991 data.skip = skip;
992 data.conflicting_refname = NULL;
993 dir = get_ref_dir(dir->entries[pos]);
994 sort_ref_dir(dir);
995 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
996 strbuf_addf(err, "'%s' exists; cannot create '%s'",
997 data.conflicting_refname, refname);
998 goto cleanup;
1003 if (extras) {
1005 * Check for entries in extras that start with
1006 * "$refname/". We do that by looking for the place
1007 * where "$refname/" would be inserted in extras. If
1008 * there is an entry at that position that starts with
1009 * "$refname/" and is not in skip, then we have a
1010 * conflict.
1012 for (pos = string_list_find_insert_index(extras, dirname.buf, 0);
1013 pos < extras->nr; pos++) {
1014 const char *extra_refname = extras->items[pos].string;
1016 if (!starts_with(extra_refname, dirname.buf))
1017 break;
1019 if (!skip || !string_list_has_string(skip, extra_refname)) {
1020 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1021 refname, extra_refname);
1022 goto cleanup;
1027 /* No conflicts were found */
1028 ret = 0;
1030 cleanup:
1031 strbuf_release(&dirname);
1032 return ret;
1035 struct packed_ref_cache {
1036 struct ref_entry *root;
1039 * Count of references to the data structure in this instance,
1040 * including the pointer from ref_cache::packed if any. The
1041 * data will not be freed as long as the reference count is
1042 * nonzero.
1044 unsigned int referrers;
1047 * Iff the packed-refs file associated with this instance is
1048 * currently locked for writing, this points at the associated
1049 * lock (which is owned by somebody else). The referrer count
1050 * is also incremented when the file is locked and decremented
1051 * when it is unlocked.
1053 struct lock_file *lock;
1055 /* The metadata from when this packed-refs cache was read */
1056 struct stat_validity validity;
1060 * Future: need to be in "struct repository"
1061 * when doing a full libification.
1063 static struct ref_cache {
1064 struct ref_cache *next;
1065 struct ref_entry *loose;
1066 struct packed_ref_cache *packed;
1068 * The submodule name, or "" for the main repo. We allocate
1069 * length 1 rather than FLEX_ARRAY so that the main ref_cache
1070 * is initialized correctly.
1072 char name[1];
1073 } ref_cache, *submodule_ref_caches;
1075 /* Lock used for the main packed-refs file: */
1076 static struct lock_file packlock;
1079 * Increment the reference count of *packed_refs.
1081 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
1083 packed_refs->referrers++;
1087 * Decrease the reference count of *packed_refs. If it goes to zero,
1088 * free *packed_refs and return true; otherwise return false.
1090 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
1092 if (!--packed_refs->referrers) {
1093 free_ref_entry(packed_refs->root);
1094 stat_validity_clear(&packed_refs->validity);
1095 free(packed_refs);
1096 return 1;
1097 } else {
1098 return 0;
1102 static void clear_packed_ref_cache(struct ref_cache *refs)
1104 if (refs->packed) {
1105 struct packed_ref_cache *packed_refs = refs->packed;
1107 if (packed_refs->lock)
1108 die("internal error: packed-ref cache cleared while locked");
1109 refs->packed = NULL;
1110 release_packed_ref_cache(packed_refs);
1114 static void clear_loose_ref_cache(struct ref_cache *refs)
1116 if (refs->loose) {
1117 free_ref_entry(refs->loose);
1118 refs->loose = NULL;
1122 static struct ref_cache *create_ref_cache(const char *submodule)
1124 int len;
1125 struct ref_cache *refs;
1126 if (!submodule)
1127 submodule = "";
1128 len = strlen(submodule) + 1;
1129 refs = xcalloc(1, sizeof(struct ref_cache) + len);
1130 memcpy(refs->name, submodule, len);
1131 return refs;
1135 * Return a pointer to a ref_cache for the specified submodule. For
1136 * the main repository, use submodule==NULL. The returned structure
1137 * will be allocated and initialized but not necessarily populated; it
1138 * should not be freed.
1140 static struct ref_cache *get_ref_cache(const char *submodule)
1142 struct ref_cache *refs;
1144 if (!submodule || !*submodule)
1145 return &ref_cache;
1147 for (refs = submodule_ref_caches; refs; refs = refs->next)
1148 if (!strcmp(submodule, refs->name))
1149 return refs;
1151 refs = create_ref_cache(submodule);
1152 refs->next = submodule_ref_caches;
1153 submodule_ref_caches = refs;
1154 return refs;
1157 /* The length of a peeled reference line in packed-refs, including EOL: */
1158 #define PEELED_LINE_LENGTH 42
1161 * The packed-refs header line that we write out. Perhaps other
1162 * traits will be added later. The trailing space is required.
1164 static const char PACKED_REFS_HEADER[] =
1165 "# pack-refs with: peeled fully-peeled \n";
1168 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1169 * Return a pointer to the refname within the line (null-terminated),
1170 * or NULL if there was a problem.
1172 static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1174 const char *ref;
1177 * 42: the answer to everything.
1179 * In this case, it happens to be the answer to
1180 * 40 (length of sha1 hex representation)
1181 * +1 (space in between hex and name)
1182 * +1 (newline at the end of the line)
1184 if (line->len <= 42)
1185 return NULL;
1187 if (get_sha1_hex(line->buf, sha1) < 0)
1188 return NULL;
1189 if (!isspace(line->buf[40]))
1190 return NULL;
1192 ref = line->buf + 41;
1193 if (isspace(*ref))
1194 return NULL;
1196 if (line->buf[line->len - 1] != '\n')
1197 return NULL;
1198 line->buf[--line->len] = 0;
1200 return ref;
1204 * Read f, which is a packed-refs file, into dir.
1206 * A comment line of the form "# pack-refs with: " may contain zero or
1207 * more traits. We interpret the traits as follows:
1209 * No traits:
1211 * Probably no references are peeled. But if the file contains a
1212 * peeled value for a reference, we will use it.
1214 * peeled:
1216 * References under "refs/tags/", if they *can* be peeled, *are*
1217 * peeled in this file. References outside of "refs/tags/" are
1218 * probably not peeled even if they could have been, but if we find
1219 * a peeled value for such a reference we will use it.
1221 * fully-peeled:
1223 * All references in the file that can be peeled are peeled.
1224 * Inversely (and this is more important), any references in the
1225 * file for which no peeled value is recorded is not peelable. This
1226 * trait should typically be written alongside "peeled" for
1227 * compatibility with older clients, but we do not require it
1228 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1230 static void read_packed_refs(FILE *f, struct ref_dir *dir)
1232 struct ref_entry *last = NULL;
1233 struct strbuf line = STRBUF_INIT;
1234 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1236 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1237 unsigned char sha1[20];
1238 const char *refname;
1239 const char *traits;
1241 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1242 if (strstr(traits, " fully-peeled "))
1243 peeled = PEELED_FULLY;
1244 else if (strstr(traits, " peeled "))
1245 peeled = PEELED_TAGS;
1246 /* perhaps other traits later as well */
1247 continue;
1250 refname = parse_ref_line(&line, sha1);
1251 if (refname) {
1252 int flag = REF_ISPACKED;
1254 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1255 if (!refname_is_safe(refname))
1256 die("packed refname is dangerous: %s", refname);
1257 hashclr(sha1);
1258 flag |= REF_BAD_NAME | REF_ISBROKEN;
1260 last = create_ref_entry(refname, sha1, flag, 0);
1261 if (peeled == PEELED_FULLY ||
1262 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1263 last->flag |= REF_KNOWS_PEELED;
1264 add_ref(dir, last);
1265 continue;
1267 if (last &&
1268 line.buf[0] == '^' &&
1269 line.len == PEELED_LINE_LENGTH &&
1270 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1271 !get_sha1_hex(line.buf + 1, sha1)) {
1272 hashcpy(last->u.value.peeled.hash, sha1);
1274 * Regardless of what the file header said,
1275 * we definitely know the value of *this*
1276 * reference:
1278 last->flag |= REF_KNOWS_PEELED;
1282 strbuf_release(&line);
1286 * Get the packed_ref_cache for the specified ref_cache, creating it
1287 * if necessary.
1289 static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1291 const char *packed_refs_file;
1293 if (*refs->name)
1294 packed_refs_file = git_path_submodule(refs->name, "packed-refs");
1295 else
1296 packed_refs_file = git_path("packed-refs");
1298 if (refs->packed &&
1299 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1300 clear_packed_ref_cache(refs);
1302 if (!refs->packed) {
1303 FILE *f;
1305 refs->packed = xcalloc(1, sizeof(*refs->packed));
1306 acquire_packed_ref_cache(refs->packed);
1307 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1308 f = fopen(packed_refs_file, "r");
1309 if (f) {
1310 stat_validity_update(&refs->packed->validity, fileno(f));
1311 read_packed_refs(f, get_ref_dir(refs->packed->root));
1312 fclose(f);
1315 return refs->packed;
1318 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1320 return get_ref_dir(packed_ref_cache->root);
1323 static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1325 return get_packed_ref_dir(get_packed_ref_cache(refs));
1329 * Add a reference to the in-memory packed reference cache. This may
1330 * only be called while the packed-refs file is locked (see
1331 * lock_packed_refs()). To actually write the packed-refs file, call
1332 * commit_packed_refs().
1334 static void add_packed_ref(const char *refname, const unsigned char *sha1)
1336 struct packed_ref_cache *packed_ref_cache =
1337 get_packed_ref_cache(&ref_cache);
1339 if (!packed_ref_cache->lock)
1340 die("internal error: packed refs not locked");
1341 add_ref(get_packed_ref_dir(packed_ref_cache),
1342 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1346 * Read the loose references from the namespace dirname into dir
1347 * (without recursing). dirname must end with '/'. dir must be the
1348 * directory entry corresponding to dirname.
1350 static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1352 struct ref_cache *refs = dir->ref_cache;
1353 DIR *d;
1354 const char *path;
1355 struct dirent *de;
1356 int dirnamelen = strlen(dirname);
1357 struct strbuf refname;
1359 if (*refs->name)
1360 path = git_path_submodule(refs->name, "%s", dirname);
1361 else
1362 path = git_path("%s", dirname);
1364 d = opendir(path);
1365 if (!d)
1366 return;
1368 strbuf_init(&refname, dirnamelen + 257);
1369 strbuf_add(&refname, dirname, dirnamelen);
1371 while ((de = readdir(d)) != NULL) {
1372 unsigned char sha1[20];
1373 struct stat st;
1374 int flag;
1375 const char *refdir;
1377 if (de->d_name[0] == '.')
1378 continue;
1379 if (ends_with(de->d_name, ".lock"))
1380 continue;
1381 strbuf_addstr(&refname, de->d_name);
1382 refdir = *refs->name
1383 ? git_path_submodule(refs->name, "%s", refname.buf)
1384 : git_path("%s", refname.buf);
1385 if (stat(refdir, &st) < 0) {
1386 ; /* silently ignore */
1387 } else if (S_ISDIR(st.st_mode)) {
1388 strbuf_addch(&refname, '/');
1389 add_entry_to_dir(dir,
1390 create_dir_entry(refs, refname.buf,
1391 refname.len, 1));
1392 } else {
1393 int read_ok;
1395 if (*refs->name) {
1396 hashclr(sha1);
1397 flag = 0;
1398 read_ok = !resolve_gitlink_ref(refs->name,
1399 refname.buf, sha1);
1400 } else {
1401 read_ok = !read_ref_full(refname.buf,
1402 RESOLVE_REF_READING,
1403 sha1, &flag);
1406 if (!read_ok) {
1407 hashclr(sha1);
1408 flag |= REF_ISBROKEN;
1409 } else if (is_null_sha1(sha1)) {
1411 * It is so astronomically unlikely
1412 * that NULL_SHA1 is the SHA-1 of an
1413 * actual object that we consider its
1414 * appearance in a loose reference
1415 * file to be repo corruption
1416 * (probably due to a software bug).
1418 flag |= REF_ISBROKEN;
1421 if (check_refname_format(refname.buf,
1422 REFNAME_ALLOW_ONELEVEL)) {
1423 if (!refname_is_safe(refname.buf))
1424 die("loose refname is dangerous: %s", refname.buf);
1425 hashclr(sha1);
1426 flag |= REF_BAD_NAME | REF_ISBROKEN;
1428 add_entry_to_dir(dir,
1429 create_ref_entry(refname.buf, sha1, flag, 0));
1431 strbuf_setlen(&refname, dirnamelen);
1433 strbuf_release(&refname);
1434 closedir(d);
1437 static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1439 if (!refs->loose) {
1441 * Mark the top-level directory complete because we
1442 * are about to read the only subdirectory that can
1443 * hold references:
1445 refs->loose = create_dir_entry(refs, "", 0, 0);
1447 * Create an incomplete entry for "refs/":
1449 add_entry_to_dir(get_ref_dir(refs->loose),
1450 create_dir_entry(refs, "refs/", 5, 1));
1452 return get_ref_dir(refs->loose);
1455 /* We allow "recursive" symbolic refs. Only within reason, though */
1456 #define MAXDEPTH 5
1457 #define MAXREFLEN (1024)
1460 * Called by resolve_gitlink_ref_recursive() after it failed to read
1461 * from the loose refs in ref_cache refs. Find <refname> in the
1462 * packed-refs file for the submodule.
1464 static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1465 const char *refname, unsigned char *sha1)
1467 struct ref_entry *ref;
1468 struct ref_dir *dir = get_packed_refs(refs);
1470 ref = find_ref(dir, refname);
1471 if (ref == NULL)
1472 return -1;
1474 hashcpy(sha1, ref->u.value.oid.hash);
1475 return 0;
1478 static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1479 const char *refname, unsigned char *sha1,
1480 int recursion)
1482 int fd, len;
1483 char buffer[128], *p;
1484 const char *path;
1486 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1487 return -1;
1488 path = *refs->name
1489 ? git_path_submodule(refs->name, "%s", refname)
1490 : git_path("%s", refname);
1491 fd = open(path, O_RDONLY);
1492 if (fd < 0)
1493 return resolve_gitlink_packed_ref(refs, refname, sha1);
1495 len = read(fd, buffer, sizeof(buffer)-1);
1496 close(fd);
1497 if (len < 0)
1498 return -1;
1499 while (len && isspace(buffer[len-1]))
1500 len--;
1501 buffer[len] = 0;
1503 /* Was it a detached head or an old-fashioned symlink? */
1504 if (!get_sha1_hex(buffer, sha1))
1505 return 0;
1507 /* Symref? */
1508 if (strncmp(buffer, "ref:", 4))
1509 return -1;
1510 p = buffer + 4;
1511 while (isspace(*p))
1512 p++;
1514 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1517 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1519 int len = strlen(path), retval;
1520 char *submodule;
1521 struct ref_cache *refs;
1523 while (len && path[len-1] == '/')
1524 len--;
1525 if (!len)
1526 return -1;
1527 submodule = xstrndup(path, len);
1528 refs = get_ref_cache(submodule);
1529 free(submodule);
1531 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1532 return retval;
1536 * Return the ref_entry for the given refname from the packed
1537 * references. If it does not exist, return NULL.
1539 static struct ref_entry *get_packed_ref(const char *refname)
1541 return find_ref(get_packed_refs(&ref_cache), refname);
1545 * A loose ref file doesn't exist; check for a packed ref. The
1546 * options are forwarded from resolve_safe_unsafe().
1548 static int resolve_missing_loose_ref(const char *refname,
1549 int resolve_flags,
1550 unsigned char *sha1,
1551 int *flags)
1553 struct ref_entry *entry;
1556 * The loose reference file does not exist; check for a packed
1557 * reference.
1559 entry = get_packed_ref(refname);
1560 if (entry) {
1561 hashcpy(sha1, entry->u.value.oid.hash);
1562 if (flags)
1563 *flags |= REF_ISPACKED;
1564 return 0;
1566 /* The reference is not a packed reference, either. */
1567 if (resolve_flags & RESOLVE_REF_READING) {
1568 errno = ENOENT;
1569 return -1;
1570 } else {
1571 hashclr(sha1);
1572 return 0;
1576 /* This function needs to return a meaningful errno on failure */
1577 static const char *resolve_ref_unsafe_1(const char *refname,
1578 int resolve_flags,
1579 unsigned char *sha1,
1580 int *flags,
1581 struct strbuf *sb_path)
1583 int depth = MAXDEPTH;
1584 ssize_t len;
1585 char buffer[256];
1586 static char refname_buffer[256];
1587 int bad_name = 0;
1589 if (flags)
1590 *flags = 0;
1592 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1593 if (flags)
1594 *flags |= REF_BAD_NAME;
1596 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1597 !refname_is_safe(refname)) {
1598 errno = EINVAL;
1599 return NULL;
1602 * dwim_ref() uses REF_ISBROKEN to distinguish between
1603 * missing refs and refs that were present but invalid,
1604 * to complain about the latter to stderr.
1606 * We don't know whether the ref exists, so don't set
1607 * REF_ISBROKEN yet.
1609 bad_name = 1;
1611 for (;;) {
1612 const char *path;
1613 struct stat st;
1614 char *buf;
1615 int fd;
1617 if (--depth < 0) {
1618 errno = ELOOP;
1619 return NULL;
1622 strbuf_reset(sb_path);
1623 strbuf_git_path(sb_path, "%s", refname);
1624 path = sb_path->buf;
1627 * We might have to loop back here to avoid a race
1628 * condition: first we lstat() the file, then we try
1629 * to read it as a link or as a file. But if somebody
1630 * changes the type of the file (file <-> directory
1631 * <-> symlink) between the lstat() and reading, then
1632 * we don't want to report that as an error but rather
1633 * try again starting with the lstat().
1635 stat_ref:
1636 if (lstat(path, &st) < 0) {
1637 if (errno != ENOENT)
1638 return NULL;
1639 if (resolve_missing_loose_ref(refname, resolve_flags,
1640 sha1, flags))
1641 return NULL;
1642 if (bad_name) {
1643 hashclr(sha1);
1644 if (flags)
1645 *flags |= REF_ISBROKEN;
1647 return refname;
1650 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1651 if (S_ISLNK(st.st_mode)) {
1652 len = readlink(path, buffer, sizeof(buffer)-1);
1653 if (len < 0) {
1654 if (errno == ENOENT || errno == EINVAL)
1655 /* inconsistent with lstat; retry */
1656 goto stat_ref;
1657 else
1658 return NULL;
1660 buffer[len] = 0;
1661 if (starts_with(buffer, "refs/") &&
1662 !check_refname_format(buffer, 0)) {
1663 strcpy(refname_buffer, buffer);
1664 refname = refname_buffer;
1665 if (flags)
1666 *flags |= REF_ISSYMREF;
1667 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1668 hashclr(sha1);
1669 return refname;
1671 continue;
1675 /* Is it a directory? */
1676 if (S_ISDIR(st.st_mode)) {
1677 errno = EISDIR;
1678 return NULL;
1682 * Anything else, just open it and try to use it as
1683 * a ref
1685 fd = open(path, O_RDONLY);
1686 if (fd < 0) {
1687 if (errno == ENOENT)
1688 /* inconsistent with lstat; retry */
1689 goto stat_ref;
1690 else
1691 return NULL;
1693 len = read_in_full(fd, buffer, sizeof(buffer)-1);
1694 if (len < 0) {
1695 int save_errno = errno;
1696 close(fd);
1697 errno = save_errno;
1698 return NULL;
1700 close(fd);
1701 while (len && isspace(buffer[len-1]))
1702 len--;
1703 buffer[len] = '\0';
1706 * Is it a symbolic ref?
1708 if (!starts_with(buffer, "ref:")) {
1710 * Please note that FETCH_HEAD has a second
1711 * line containing other data.
1713 if (get_sha1_hex(buffer, sha1) ||
1714 (buffer[40] != '\0' && !isspace(buffer[40]))) {
1715 if (flags)
1716 *flags |= REF_ISBROKEN;
1717 errno = EINVAL;
1718 return NULL;
1720 if (bad_name) {
1721 hashclr(sha1);
1722 if (flags)
1723 *flags |= REF_ISBROKEN;
1725 return refname;
1727 if (flags)
1728 *flags |= REF_ISSYMREF;
1729 buf = buffer + 4;
1730 while (isspace(*buf))
1731 buf++;
1732 refname = strcpy(refname_buffer, buf);
1733 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1734 hashclr(sha1);
1735 return refname;
1737 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1738 if (flags)
1739 *flags |= REF_ISBROKEN;
1741 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1742 !refname_is_safe(buf)) {
1743 errno = EINVAL;
1744 return NULL;
1746 bad_name = 1;
1751 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1752 unsigned char *sha1, int *flags)
1754 struct strbuf sb_path = STRBUF_INIT;
1755 const char *ret = resolve_ref_unsafe_1(refname, resolve_flags,
1756 sha1, flags, &sb_path);
1757 strbuf_release(&sb_path);
1758 return ret;
1761 char *resolve_refdup(const char *refname, int resolve_flags,
1762 unsigned char *sha1, int *flags)
1764 return xstrdup_or_null(resolve_ref_unsafe(refname, resolve_flags,
1765 sha1, flags));
1768 /* The argument to filter_refs */
1769 struct ref_filter {
1770 const char *pattern;
1771 each_ref_fn *fn;
1772 void *cb_data;
1775 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1777 if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
1778 return 0;
1779 return -1;
1782 int read_ref(const char *refname, unsigned char *sha1)
1784 return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
1787 int ref_exists(const char *refname)
1789 unsigned char sha1[20];
1790 return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
1793 static int filter_refs(const char *refname, const struct object_id *oid,
1794 int flags, void *data)
1796 struct ref_filter *filter = (struct ref_filter *)data;
1798 if (wildmatch(filter->pattern, refname, 0, NULL))
1799 return 0;
1800 return filter->fn(refname, oid, flags, filter->cb_data);
1803 enum peel_status {
1804 /* object was peeled successfully: */
1805 PEEL_PEELED = 0,
1808 * object cannot be peeled because the named object (or an
1809 * object referred to by a tag in the peel chain), does not
1810 * exist.
1812 PEEL_INVALID = -1,
1814 /* object cannot be peeled because it is not a tag: */
1815 PEEL_NON_TAG = -2,
1817 /* ref_entry contains no peeled value because it is a symref: */
1818 PEEL_IS_SYMREF = -3,
1821 * ref_entry cannot be peeled because it is broken (i.e., the
1822 * symbolic reference cannot even be resolved to an object
1823 * name):
1825 PEEL_BROKEN = -4
1829 * Peel the named object; i.e., if the object is a tag, resolve the
1830 * tag recursively until a non-tag is found. If successful, store the
1831 * result to sha1 and return PEEL_PEELED. If the object is not a tag
1832 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
1833 * and leave sha1 unchanged.
1835 static enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
1837 struct object *o = lookup_unknown_object(name);
1839 if (o->type == OBJ_NONE) {
1840 int type = sha1_object_info(name, NULL);
1841 if (type < 0 || !object_as_type(o, type, 0))
1842 return PEEL_INVALID;
1845 if (o->type != OBJ_TAG)
1846 return PEEL_NON_TAG;
1848 o = deref_tag_noverify(o);
1849 if (!o)
1850 return PEEL_INVALID;
1852 hashcpy(sha1, o->sha1);
1853 return PEEL_PEELED;
1857 * Peel the entry (if possible) and return its new peel_status. If
1858 * repeel is true, re-peel the entry even if there is an old peeled
1859 * value that is already stored in it.
1861 * It is OK to call this function with a packed reference entry that
1862 * might be stale and might even refer to an object that has since
1863 * been garbage-collected. In such a case, if the entry has
1864 * REF_KNOWS_PEELED then leave the status unchanged and return
1865 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1867 static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1869 enum peel_status status;
1871 if (entry->flag & REF_KNOWS_PEELED) {
1872 if (repeel) {
1873 entry->flag &= ~REF_KNOWS_PEELED;
1874 oidclr(&entry->u.value.peeled);
1875 } else {
1876 return is_null_oid(&entry->u.value.peeled) ?
1877 PEEL_NON_TAG : PEEL_PEELED;
1880 if (entry->flag & REF_ISBROKEN)
1881 return PEEL_BROKEN;
1882 if (entry->flag & REF_ISSYMREF)
1883 return PEEL_IS_SYMREF;
1885 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1886 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1887 entry->flag |= REF_KNOWS_PEELED;
1888 return status;
1891 int peel_ref(const char *refname, unsigned char *sha1)
1893 int flag;
1894 unsigned char base[20];
1896 if (current_ref && (current_ref->name == refname
1897 || !strcmp(current_ref->name, refname))) {
1898 if (peel_entry(current_ref, 0))
1899 return -1;
1900 hashcpy(sha1, current_ref->u.value.peeled.hash);
1901 return 0;
1904 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1905 return -1;
1908 * If the reference is packed, read its ref_entry from the
1909 * cache in the hope that we already know its peeled value.
1910 * We only try this optimization on packed references because
1911 * (a) forcing the filling of the loose reference cache could
1912 * be expensive and (b) loose references anyway usually do not
1913 * have REF_KNOWS_PEELED.
1915 if (flag & REF_ISPACKED) {
1916 struct ref_entry *r = get_packed_ref(refname);
1917 if (r) {
1918 if (peel_entry(r, 0))
1919 return -1;
1920 hashcpy(sha1, r->u.value.peeled.hash);
1921 return 0;
1925 return peel_object(base, sha1);
1928 struct warn_if_dangling_data {
1929 FILE *fp;
1930 const char *refname;
1931 const struct string_list *refnames;
1932 const char *msg_fmt;
1935 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
1936 int flags, void *cb_data)
1938 struct warn_if_dangling_data *d = cb_data;
1939 const char *resolves_to;
1940 struct object_id junk;
1942 if (!(flags & REF_ISSYMREF))
1943 return 0;
1945 resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
1946 if (!resolves_to
1947 || (d->refname
1948 ? strcmp(resolves_to, d->refname)
1949 : !string_list_has_string(d->refnames, resolves_to))) {
1950 return 0;
1953 fprintf(d->fp, d->msg_fmt, refname);
1954 fputc('\n', d->fp);
1955 return 0;
1958 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1960 struct warn_if_dangling_data data;
1962 data.fp = fp;
1963 data.refname = refname;
1964 data.refnames = NULL;
1965 data.msg_fmt = msg_fmt;
1966 for_each_rawref(warn_if_dangling_symref, &data);
1969 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
1971 struct warn_if_dangling_data data;
1973 data.fp = fp;
1974 data.refname = NULL;
1975 data.refnames = refnames;
1976 data.msg_fmt = msg_fmt;
1977 for_each_rawref(warn_if_dangling_symref, &data);
1981 * Call fn for each reference in the specified ref_cache, omitting
1982 * references not in the containing_dir of base. fn is called for all
1983 * references, including broken ones. If fn ever returns a non-zero
1984 * value, stop the iteration and return that value; otherwise, return
1985 * 0.
1987 static int do_for_each_entry(struct ref_cache *refs, const char *base,
1988 each_ref_entry_fn fn, void *cb_data)
1990 struct packed_ref_cache *packed_ref_cache;
1991 struct ref_dir *loose_dir;
1992 struct ref_dir *packed_dir;
1993 int retval = 0;
1996 * We must make sure that all loose refs are read before accessing the
1997 * packed-refs file; this avoids a race condition in which loose refs
1998 * are migrated to the packed-refs file by a simultaneous process, but
1999 * our in-memory view is from before the migration. get_packed_ref_cache()
2000 * takes care of making sure our view is up to date with what is on
2001 * disk.
2003 loose_dir = get_loose_refs(refs);
2004 if (base && *base) {
2005 loose_dir = find_containing_dir(loose_dir, base, 0);
2007 if (loose_dir)
2008 prime_ref_dir(loose_dir);
2010 packed_ref_cache = get_packed_ref_cache(refs);
2011 acquire_packed_ref_cache(packed_ref_cache);
2012 packed_dir = get_packed_ref_dir(packed_ref_cache);
2013 if (base && *base) {
2014 packed_dir = find_containing_dir(packed_dir, base, 0);
2017 if (packed_dir && loose_dir) {
2018 sort_ref_dir(packed_dir);
2019 sort_ref_dir(loose_dir);
2020 retval = do_for_each_entry_in_dirs(
2021 packed_dir, loose_dir, fn, cb_data);
2022 } else if (packed_dir) {
2023 sort_ref_dir(packed_dir);
2024 retval = do_for_each_entry_in_dir(
2025 packed_dir, 0, fn, cb_data);
2026 } else if (loose_dir) {
2027 sort_ref_dir(loose_dir);
2028 retval = do_for_each_entry_in_dir(
2029 loose_dir, 0, fn, cb_data);
2032 release_packed_ref_cache(packed_ref_cache);
2033 return retval;
2037 * Call fn for each reference in the specified ref_cache for which the
2038 * refname begins with base. If trim is non-zero, then trim that many
2039 * characters off the beginning of each refname before passing the
2040 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
2041 * broken references in the iteration. If fn ever returns a non-zero
2042 * value, stop the iteration and return that value; otherwise, return
2043 * 0.
2045 static int do_for_each_ref(struct ref_cache *refs, const char *base,
2046 each_ref_fn fn, int trim, int flags, void *cb_data)
2048 struct ref_entry_cb data;
2049 data.base = base;
2050 data.trim = trim;
2051 data.flags = flags;
2052 data.fn = fn;
2053 data.cb_data = cb_data;
2055 if (ref_paranoia < 0)
2056 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
2057 if (ref_paranoia)
2058 data.flags |= DO_FOR_EACH_INCLUDE_BROKEN;
2060 return do_for_each_entry(refs, base, do_one_ref, &data);
2063 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
2065 struct object_id oid;
2066 int flag;
2068 if (submodule) {
2069 if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
2070 return fn("HEAD", &oid, 0, cb_data);
2072 return 0;
2075 if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
2076 return fn("HEAD", &oid, flag, cb_data);
2078 return 0;
2081 int head_ref(each_ref_fn fn, void *cb_data)
2083 return do_head_ref(NULL, fn, cb_data);
2086 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2088 return do_head_ref(submodule, fn, cb_data);
2091 int for_each_ref(each_ref_fn fn, void *cb_data)
2093 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
2096 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2098 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
2101 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
2103 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
2106 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
2107 each_ref_fn fn, void *cb_data)
2109 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
2112 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
2114 return for_each_ref_in("refs/tags/", fn, cb_data);
2117 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2119 return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
2122 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
2124 return for_each_ref_in("refs/heads/", fn, cb_data);
2127 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2129 return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
2132 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
2134 return for_each_ref_in("refs/remotes/", fn, cb_data);
2137 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2139 return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
2142 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
2144 return do_for_each_ref(&ref_cache, git_replace_ref_base, fn,
2145 strlen(git_replace_ref_base), 0, cb_data);
2148 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
2150 struct strbuf buf = STRBUF_INIT;
2151 int ret = 0;
2152 struct object_id oid;
2153 int flag;
2155 strbuf_addf(&buf, "%sHEAD", get_git_namespace());
2156 if (!read_ref_full(buf.buf, RESOLVE_REF_READING, oid.hash, &flag))
2157 ret = fn(buf.buf, &oid, flag, cb_data);
2158 strbuf_release(&buf);
2160 return ret;
2163 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
2165 struct strbuf buf = STRBUF_INIT;
2166 int ret;
2167 strbuf_addf(&buf, "%srefs/", get_git_namespace());
2168 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
2169 strbuf_release(&buf);
2170 return ret;
2173 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
2174 const char *prefix, void *cb_data)
2176 struct strbuf real_pattern = STRBUF_INIT;
2177 struct ref_filter filter;
2178 int ret;
2180 if (!prefix && !starts_with(pattern, "refs/"))
2181 strbuf_addstr(&real_pattern, "refs/");
2182 else if (prefix)
2183 strbuf_addstr(&real_pattern, prefix);
2184 strbuf_addstr(&real_pattern, pattern);
2186 if (!has_glob_specials(pattern)) {
2187 /* Append implied '/' '*' if not present. */
2188 if (real_pattern.buf[real_pattern.len - 1] != '/')
2189 strbuf_addch(&real_pattern, '/');
2190 /* No need to check for '*', there is none. */
2191 strbuf_addch(&real_pattern, '*');
2194 filter.pattern = real_pattern.buf;
2195 filter.fn = fn;
2196 filter.cb_data = cb_data;
2197 ret = for_each_ref(filter_refs, &filter);
2199 strbuf_release(&real_pattern);
2200 return ret;
2203 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
2205 return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
2208 int for_each_rawref(each_ref_fn fn, void *cb_data)
2210 return do_for_each_ref(&ref_cache, "", fn, 0,
2211 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
2214 const char *prettify_refname(const char *name)
2216 return name + (
2217 starts_with(name, "refs/heads/") ? 11 :
2218 starts_with(name, "refs/tags/") ? 10 :
2219 starts_with(name, "refs/remotes/") ? 13 :
2223 static const char *ref_rev_parse_rules[] = {
2224 "%.*s",
2225 "refs/%.*s",
2226 "refs/tags/%.*s",
2227 "refs/heads/%.*s",
2228 "refs/remotes/%.*s",
2229 "refs/remotes/%.*s/HEAD",
2230 NULL
2233 int refname_match(const char *abbrev_name, const char *full_name)
2235 const char **p;
2236 const int abbrev_name_len = strlen(abbrev_name);
2238 for (p = ref_rev_parse_rules; *p; p++) {
2239 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
2240 return 1;
2244 return 0;
2247 static void unlock_ref(struct ref_lock *lock)
2249 /* Do not free lock->lk -- atexit() still looks at them */
2250 if (lock->lk)
2251 rollback_lock_file(lock->lk);
2252 free(lock->ref_name);
2253 free(lock->orig_ref_name);
2254 free(lock);
2258 * Verify that the reference locked by lock has the value old_sha1.
2259 * Fail if the reference doesn't exist and mustexist is set. Return 0
2260 * on success. On error, write an error message to err, set errno, and
2261 * return a negative value.
2263 static int verify_lock(struct ref_lock *lock,
2264 const unsigned char *old_sha1, int mustexist,
2265 struct strbuf *err)
2267 assert(err);
2269 if (read_ref_full(lock->ref_name,
2270 mustexist ? RESOLVE_REF_READING : 0,
2271 lock->old_oid.hash, NULL)) {
2272 int save_errno = errno;
2273 strbuf_addf(err, "can't verify ref %s", lock->ref_name);
2274 errno = save_errno;
2275 return -1;
2277 if (hashcmp(lock->old_oid.hash, old_sha1)) {
2278 strbuf_addf(err, "ref %s is at %s but expected %s",
2279 lock->ref_name,
2280 sha1_to_hex(lock->old_oid.hash),
2281 sha1_to_hex(old_sha1));
2282 errno = EBUSY;
2283 return -1;
2285 return 0;
2288 static int remove_empty_directories(const char *file)
2290 /* we want to create a file but there is a directory there;
2291 * if that is an empty directory (or a directory that contains
2292 * only empty directories), remove them.
2294 struct strbuf path;
2295 int result, save_errno;
2297 strbuf_init(&path, 20);
2298 strbuf_addstr(&path, file);
2300 result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
2301 save_errno = errno;
2303 strbuf_release(&path);
2304 errno = save_errno;
2306 return result;
2310 * *string and *len will only be substituted, and *string returned (for
2311 * later free()ing) if the string passed in is a magic short-hand form
2312 * to name a branch.
2314 static char *substitute_branch_name(const char **string, int *len)
2316 struct strbuf buf = STRBUF_INIT;
2317 int ret = interpret_branch_name(*string, *len, &buf);
2319 if (ret == *len) {
2320 size_t size;
2321 *string = strbuf_detach(&buf, &size);
2322 *len = size;
2323 return (char *)*string;
2326 return NULL;
2329 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
2331 char *last_branch = substitute_branch_name(&str, &len);
2332 const char **p, *r;
2333 int refs_found = 0;
2335 *ref = NULL;
2336 for (p = ref_rev_parse_rules; *p; p++) {
2337 char fullref[PATH_MAX];
2338 unsigned char sha1_from_ref[20];
2339 unsigned char *this_result;
2340 int flag;
2342 this_result = refs_found ? sha1_from_ref : sha1;
2343 mksnpath(fullref, sizeof(fullref), *p, len, str);
2344 r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
2345 this_result, &flag);
2346 if (r) {
2347 if (!refs_found++)
2348 *ref = xstrdup(r);
2349 if (!warn_ambiguous_refs)
2350 break;
2351 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
2352 warning("ignoring dangling symref %s.", fullref);
2353 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
2354 warning("ignoring broken ref %s.", fullref);
2357 free(last_branch);
2358 return refs_found;
2361 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
2363 char *last_branch = substitute_branch_name(&str, &len);
2364 const char **p;
2365 int logs_found = 0;
2367 *log = NULL;
2368 for (p = ref_rev_parse_rules; *p; p++) {
2369 unsigned char hash[20];
2370 char path[PATH_MAX];
2371 const char *ref, *it;
2373 mksnpath(path, sizeof(path), *p, len, str);
2374 ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
2375 hash, NULL);
2376 if (!ref)
2377 continue;
2378 if (reflog_exists(path))
2379 it = path;
2380 else if (strcmp(ref, path) && reflog_exists(ref))
2381 it = ref;
2382 else
2383 continue;
2384 if (!logs_found++) {
2385 *log = xstrdup(it);
2386 hashcpy(sha1, hash);
2388 if (!warn_ambiguous_refs)
2389 break;
2391 free(last_branch);
2392 return logs_found;
2396 * Locks a ref returning the lock on success and NULL on failure.
2397 * On failure errno is set to something meaningful.
2399 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2400 const unsigned char *old_sha1,
2401 const struct string_list *extras,
2402 const struct string_list *skip,
2403 unsigned int flags, int *type_p,
2404 struct strbuf *err)
2406 const char *ref_file;
2407 const char *orig_refname = refname;
2408 struct ref_lock *lock;
2409 int last_errno = 0;
2410 int type, lflags;
2411 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
2412 int resolve_flags = 0;
2413 int attempts_remaining = 3;
2415 assert(err);
2417 lock = xcalloc(1, sizeof(struct ref_lock));
2419 if (mustexist)
2420 resolve_flags |= RESOLVE_REF_READING;
2421 if (flags & REF_DELETING) {
2422 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
2423 if (flags & REF_NODEREF)
2424 resolve_flags |= RESOLVE_REF_NO_RECURSE;
2427 refname = resolve_ref_unsafe(refname, resolve_flags,
2428 lock->old_oid.hash, &type);
2429 if (!refname && errno == EISDIR) {
2430 /* we are trying to lock foo but we used to
2431 * have foo/bar which now does not exist;
2432 * it is normal for the empty directory 'foo'
2433 * to remain.
2435 ref_file = git_path("%s", orig_refname);
2436 if (remove_empty_directories(ref_file)) {
2437 last_errno = errno;
2439 if (!verify_refname_available(orig_refname, extras, skip,
2440 get_loose_refs(&ref_cache), err))
2441 strbuf_addf(err, "there are still refs under '%s'",
2442 orig_refname);
2444 goto error_return;
2446 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
2447 lock->old_oid.hash, &type);
2449 if (type_p)
2450 *type_p = type;
2451 if (!refname) {
2452 last_errno = errno;
2453 if (last_errno != ENOTDIR ||
2454 !verify_refname_available(orig_refname, extras, skip,
2455 get_loose_refs(&ref_cache), err))
2456 strbuf_addf(err, "unable to resolve reference %s: %s",
2457 orig_refname, strerror(last_errno));
2459 goto error_return;
2462 * If the ref did not exist and we are creating it, make sure
2463 * there is no existing packed ref whose name begins with our
2464 * refname, nor a packed ref whose name is a proper prefix of
2465 * our refname.
2467 if (is_null_oid(&lock->old_oid) &&
2468 verify_refname_available(refname, extras, skip,
2469 get_packed_refs(&ref_cache), err)) {
2470 last_errno = ENOTDIR;
2471 goto error_return;
2474 lock->lk = xcalloc(1, sizeof(struct lock_file));
2476 lflags = 0;
2477 if (flags & REF_NODEREF) {
2478 refname = orig_refname;
2479 lflags |= LOCK_NO_DEREF;
2481 lock->ref_name = xstrdup(refname);
2482 lock->orig_ref_name = xstrdup(orig_refname);
2483 ref_file = git_path("%s", refname);
2485 retry:
2486 switch (safe_create_leading_directories_const(ref_file)) {
2487 case SCLD_OK:
2488 break; /* success */
2489 case SCLD_VANISHED:
2490 if (--attempts_remaining > 0)
2491 goto retry;
2492 /* fall through */
2493 default:
2494 last_errno = errno;
2495 strbuf_addf(err, "unable to create directory for %s", ref_file);
2496 goto error_return;
2499 if (hold_lock_file_for_update(lock->lk, ref_file, lflags) < 0) {
2500 last_errno = errno;
2501 if (errno == ENOENT && --attempts_remaining > 0)
2503 * Maybe somebody just deleted one of the
2504 * directories leading to ref_file. Try
2505 * again:
2507 goto retry;
2508 else {
2509 unable_to_lock_message(ref_file, errno, err);
2510 goto error_return;
2513 if (old_sha1 && verify_lock(lock, old_sha1, mustexist, err)) {
2514 last_errno = errno;
2515 goto error_return;
2517 return lock;
2519 error_return:
2520 unlock_ref(lock);
2521 errno = last_errno;
2522 return NULL;
2526 * Write an entry to the packed-refs file for the specified refname.
2527 * If peeled is non-NULL, write it as the entry's peeled value.
2529 static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2530 unsigned char *peeled)
2532 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2533 if (peeled)
2534 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2538 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2540 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2542 enum peel_status peel_status = peel_entry(entry, 0);
2544 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2545 error("internal error: %s is not a valid packed reference!",
2546 entry->name);
2547 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2548 peel_status == PEEL_PEELED ?
2549 entry->u.value.peeled.hash : NULL);
2550 return 0;
2554 * Lock the packed-refs file for writing. Flags is passed to
2555 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2556 * errno appropriately and return a nonzero value.
2558 static int lock_packed_refs(int flags)
2560 static int timeout_configured = 0;
2561 static int timeout_value = 1000;
2563 struct packed_ref_cache *packed_ref_cache;
2565 if (!timeout_configured) {
2566 git_config_get_int("core.packedrefstimeout", &timeout_value);
2567 timeout_configured = 1;
2570 if (hold_lock_file_for_update_timeout(
2571 &packlock, git_path("packed-refs"),
2572 flags, timeout_value) < 0)
2573 return -1;
2575 * Get the current packed-refs while holding the lock. If the
2576 * packed-refs file has been modified since we last read it,
2577 * this will automatically invalidate the cache and re-read
2578 * the packed-refs file.
2580 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2581 packed_ref_cache->lock = &packlock;
2582 /* Increment the reference count to prevent it from being freed: */
2583 acquire_packed_ref_cache(packed_ref_cache);
2584 return 0;
2588 * Write the current version of the packed refs cache from memory to
2589 * disk. The packed-refs file must already be locked for writing (see
2590 * lock_packed_refs()). Return zero on success. On errors, set errno
2591 * and return a nonzero value
2593 static int commit_packed_refs(void)
2595 struct packed_ref_cache *packed_ref_cache =
2596 get_packed_ref_cache(&ref_cache);
2597 int error = 0;
2598 int save_errno = 0;
2599 FILE *out;
2601 if (!packed_ref_cache->lock)
2602 die("internal error: packed-refs not locked");
2604 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2605 if (!out)
2606 die_errno("unable to fdopen packed-refs descriptor");
2608 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2609 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2610 0, write_packed_entry_fn, out);
2612 if (commit_lock_file(packed_ref_cache->lock)) {
2613 save_errno = errno;
2614 error = -1;
2616 packed_ref_cache->lock = NULL;
2617 release_packed_ref_cache(packed_ref_cache);
2618 errno = save_errno;
2619 return error;
2623 * Rollback the lockfile for the packed-refs file, and discard the
2624 * in-memory packed reference cache. (The packed-refs file will be
2625 * read anew if it is needed again after this function is called.)
2627 static void rollback_packed_refs(void)
2629 struct packed_ref_cache *packed_ref_cache =
2630 get_packed_ref_cache(&ref_cache);
2632 if (!packed_ref_cache->lock)
2633 die("internal error: packed-refs not locked");
2634 rollback_lock_file(packed_ref_cache->lock);
2635 packed_ref_cache->lock = NULL;
2636 release_packed_ref_cache(packed_ref_cache);
2637 clear_packed_ref_cache(&ref_cache);
2640 struct ref_to_prune {
2641 struct ref_to_prune *next;
2642 unsigned char sha1[20];
2643 char name[FLEX_ARRAY];
2646 struct pack_refs_cb_data {
2647 unsigned int flags;
2648 struct ref_dir *packed_refs;
2649 struct ref_to_prune *ref_to_prune;
2653 * An each_ref_entry_fn that is run over loose references only. If
2654 * the loose reference can be packed, add an entry in the packed ref
2655 * cache. If the reference should be pruned, also add it to
2656 * ref_to_prune in the pack_refs_cb_data.
2658 static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2660 struct pack_refs_cb_data *cb = cb_data;
2661 enum peel_status peel_status;
2662 struct ref_entry *packed_entry;
2663 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2665 /* ALWAYS pack tags */
2666 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2667 return 0;
2669 /* Do not pack symbolic or broken refs: */
2670 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2671 return 0;
2673 /* Add a packed ref cache entry equivalent to the loose entry. */
2674 peel_status = peel_entry(entry, 1);
2675 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2676 die("internal error peeling reference %s (%s)",
2677 entry->name, oid_to_hex(&entry->u.value.oid));
2678 packed_entry = find_ref(cb->packed_refs, entry->name);
2679 if (packed_entry) {
2680 /* Overwrite existing packed entry with info from loose entry */
2681 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2682 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2683 } else {
2684 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2685 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2686 add_ref(cb->packed_refs, packed_entry);
2688 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2690 /* Schedule the loose reference for pruning if requested. */
2691 if ((cb->flags & PACK_REFS_PRUNE)) {
2692 int namelen = strlen(entry->name) + 1;
2693 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2694 hashcpy(n->sha1, entry->u.value.oid.hash);
2695 strcpy(n->name, entry->name);
2696 n->next = cb->ref_to_prune;
2697 cb->ref_to_prune = n;
2699 return 0;
2703 * Remove empty parents, but spare refs/ and immediate subdirs.
2704 * Note: munges *name.
2706 static void try_remove_empty_parents(char *name)
2708 char *p, *q;
2709 int i;
2710 p = name;
2711 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2712 while (*p && *p != '/')
2713 p++;
2714 /* tolerate duplicate slashes; see check_refname_format() */
2715 while (*p == '/')
2716 p++;
2718 for (q = p; *q; q++)
2720 while (1) {
2721 while (q > p && *q != '/')
2722 q--;
2723 while (q > p && *(q-1) == '/')
2724 q--;
2725 if (q == p)
2726 break;
2727 *q = '\0';
2728 if (rmdir(git_path("%s", name)))
2729 break;
2733 /* make sure nobody touched the ref, and unlink */
2734 static void prune_ref(struct ref_to_prune *r)
2736 struct ref_transaction *transaction;
2737 struct strbuf err = STRBUF_INIT;
2739 if (check_refname_format(r->name, 0))
2740 return;
2742 transaction = ref_transaction_begin(&err);
2743 if (!transaction ||
2744 ref_transaction_delete(transaction, r->name, r->sha1,
2745 REF_ISPRUNING, NULL, &err) ||
2746 ref_transaction_commit(transaction, &err)) {
2747 ref_transaction_free(transaction);
2748 error("%s", err.buf);
2749 strbuf_release(&err);
2750 return;
2752 ref_transaction_free(transaction);
2753 strbuf_release(&err);
2754 try_remove_empty_parents(r->name);
2757 static void prune_refs(struct ref_to_prune *r)
2759 while (r) {
2760 prune_ref(r);
2761 r = r->next;
2765 int pack_refs(unsigned int flags)
2767 struct pack_refs_cb_data cbdata;
2769 memset(&cbdata, 0, sizeof(cbdata));
2770 cbdata.flags = flags;
2772 lock_packed_refs(LOCK_DIE_ON_ERROR);
2773 cbdata.packed_refs = get_packed_refs(&ref_cache);
2775 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2776 pack_if_possible_fn, &cbdata);
2778 if (commit_packed_refs())
2779 die_errno("unable to overwrite old ref-pack file");
2781 prune_refs(cbdata.ref_to_prune);
2782 return 0;
2786 * Rewrite the packed-refs file, omitting any refs listed in
2787 * 'refnames'. On error, leave packed-refs unchanged, write an error
2788 * message to 'err', and return a nonzero value.
2790 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2792 static int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2794 struct ref_dir *packed;
2795 struct string_list_item *refname;
2796 int ret, needs_repacking = 0, removed = 0;
2798 assert(err);
2800 /* Look for a packed ref */
2801 for_each_string_list_item(refname, refnames) {
2802 if (get_packed_ref(refname->string)) {
2803 needs_repacking = 1;
2804 break;
2808 /* Avoid locking if we have nothing to do */
2809 if (!needs_repacking)
2810 return 0; /* no refname exists in packed refs */
2812 if (lock_packed_refs(0)) {
2813 unable_to_lock_message(git_path("packed-refs"), errno, err);
2814 return -1;
2816 packed = get_packed_refs(&ref_cache);
2818 /* Remove refnames from the cache */
2819 for_each_string_list_item(refname, refnames)
2820 if (remove_entry(packed, refname->string) != -1)
2821 removed = 1;
2822 if (!removed) {
2824 * All packed entries disappeared while we were
2825 * acquiring the lock.
2827 rollback_packed_refs();
2828 return 0;
2831 /* Write what remains */
2832 ret = commit_packed_refs();
2833 if (ret)
2834 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2835 strerror(errno));
2836 return ret;
2839 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2841 assert(err);
2843 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2845 * loose. The loose file name is the same as the
2846 * lockfile name, minus ".lock":
2848 char *loose_filename = get_locked_file_path(lock->lk);
2849 int res = unlink_or_msg(loose_filename, err);
2850 free(loose_filename);
2851 if (res)
2852 return 1;
2854 return 0;
2857 int delete_ref(const char *refname, const unsigned char *old_sha1,
2858 unsigned int flags)
2860 struct ref_transaction *transaction;
2861 struct strbuf err = STRBUF_INIT;
2863 transaction = ref_transaction_begin(&err);
2864 if (!transaction ||
2865 ref_transaction_delete(transaction, refname, old_sha1,
2866 flags, NULL, &err) ||
2867 ref_transaction_commit(transaction, &err)) {
2868 error("%s", err.buf);
2869 ref_transaction_free(transaction);
2870 strbuf_release(&err);
2871 return 1;
2873 ref_transaction_free(transaction);
2874 strbuf_release(&err);
2875 return 0;
2878 int delete_refs(struct string_list *refnames)
2880 struct strbuf err = STRBUF_INIT;
2881 int i, result = 0;
2883 if (!refnames->nr)
2884 return 0;
2886 result = repack_without_refs(refnames, &err);
2887 if (result) {
2889 * If we failed to rewrite the packed-refs file, then
2890 * it is unsafe to try to remove loose refs, because
2891 * doing so might expose an obsolete packed value for
2892 * a reference that might even point at an object that
2893 * has been garbage collected.
2895 if (refnames->nr == 1)
2896 error(_("could not delete reference %s: %s"),
2897 refnames->items[0].string, err.buf);
2898 else
2899 error(_("could not delete references: %s"), err.buf);
2901 goto out;
2904 for (i = 0; i < refnames->nr; i++) {
2905 const char *refname = refnames->items[i].string;
2907 if (delete_ref(refname, NULL, 0))
2908 result |= error(_("could not remove reference %s"), refname);
2911 out:
2912 strbuf_release(&err);
2913 return result;
2917 * People using contrib's git-new-workdir have .git/logs/refs ->
2918 * /some/other/path/.git/logs/refs, and that may live on another device.
2920 * IOW, to avoid cross device rename errors, the temporary renamed log must
2921 * live into logs/refs.
2923 #define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2925 static int rename_tmp_log(const char *newrefname)
2927 int attempts_remaining = 4;
2929 retry:
2930 switch (safe_create_leading_directories_const(git_path("logs/%s", newrefname))) {
2931 case SCLD_OK:
2932 break; /* success */
2933 case SCLD_VANISHED:
2934 if (--attempts_remaining > 0)
2935 goto retry;
2936 /* fall through */
2937 default:
2938 error("unable to create directory for %s", newrefname);
2939 return -1;
2942 if (rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
2943 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2945 * rename(a, b) when b is an existing
2946 * directory ought to result in ISDIR, but
2947 * Solaris 5.8 gives ENOTDIR. Sheesh.
2949 if (remove_empty_directories(git_path("logs/%s", newrefname))) {
2950 error("Directory not empty: logs/%s", newrefname);
2951 return -1;
2953 goto retry;
2954 } else if (errno == ENOENT && --attempts_remaining > 0) {
2956 * Maybe another process just deleted one of
2957 * the directories in the path to newrefname.
2958 * Try again from the beginning.
2960 goto retry;
2961 } else {
2962 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2963 newrefname, strerror(errno));
2964 return -1;
2967 return 0;
2970 static int rename_ref_available(const char *oldname, const char *newname)
2972 struct string_list skip = STRING_LIST_INIT_NODUP;
2973 struct strbuf err = STRBUF_INIT;
2974 int ret;
2976 string_list_insert(&skip, oldname);
2977 ret = !verify_refname_available(newname, NULL, &skip,
2978 get_packed_refs(&ref_cache), &err)
2979 && !verify_refname_available(newname, NULL, &skip,
2980 get_loose_refs(&ref_cache), &err);
2981 if (!ret)
2982 error("%s", err.buf);
2984 string_list_clear(&skip, 0);
2985 strbuf_release(&err);
2986 return ret;
2989 static int write_ref_to_lockfile(struct ref_lock *lock,
2990 const unsigned char *sha1, struct strbuf *err);
2991 static int commit_ref_update(struct ref_lock *lock,
2992 const unsigned char *sha1, const char *logmsg,
2993 int flags, struct strbuf *err);
2995 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2997 unsigned char sha1[20], orig_sha1[20];
2998 int flag = 0, logmoved = 0;
2999 struct ref_lock *lock;
3000 struct stat loginfo;
3001 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
3002 const char *symref = NULL;
3003 struct strbuf err = STRBUF_INIT;
3005 if (log && S_ISLNK(loginfo.st_mode))
3006 return error("reflog for %s is a symlink", oldrefname);
3008 symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
3009 orig_sha1, &flag);
3010 if (flag & REF_ISSYMREF)
3011 return error("refname %s is a symbolic ref, renaming it is not supported",
3012 oldrefname);
3013 if (!symref)
3014 return error("refname %s not found", oldrefname);
3016 if (!rename_ref_available(oldrefname, newrefname))
3017 return 1;
3019 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
3020 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
3021 oldrefname, strerror(errno));
3023 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
3024 error("unable to delete old %s", oldrefname);
3025 goto rollback;
3028 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
3029 delete_ref(newrefname, sha1, REF_NODEREF)) {
3030 if (errno==EISDIR) {
3031 if (remove_empty_directories(git_path("%s", newrefname))) {
3032 error("Directory not empty: %s", newrefname);
3033 goto rollback;
3035 } else {
3036 error("unable to delete existing %s", newrefname);
3037 goto rollback;
3041 if (log && rename_tmp_log(newrefname))
3042 goto rollback;
3044 logmoved = log;
3046 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);
3047 if (!lock) {
3048 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
3049 strbuf_release(&err);
3050 goto rollback;
3052 hashcpy(lock->old_oid.hash, orig_sha1);
3054 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
3055 commit_ref_update(lock, orig_sha1, logmsg, 0, &err)) {
3056 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
3057 strbuf_release(&err);
3058 goto rollback;
3061 return 0;
3063 rollback:
3064 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);
3065 if (!lock) {
3066 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
3067 strbuf_release(&err);
3068 goto rollbacklog;
3071 flag = log_all_ref_updates;
3072 log_all_ref_updates = 0;
3073 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
3074 commit_ref_update(lock, orig_sha1, NULL, 0, &err)) {
3075 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
3076 strbuf_release(&err);
3078 log_all_ref_updates = flag;
3080 rollbacklog:
3081 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
3082 error("unable to restore logfile %s from %s: %s",
3083 oldrefname, newrefname, strerror(errno));
3084 if (!logmoved && log &&
3085 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
3086 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
3087 oldrefname, strerror(errno));
3089 return 1;
3092 static int close_ref(struct ref_lock *lock)
3094 if (close_lock_file(lock->lk))
3095 return -1;
3096 return 0;
3099 static int commit_ref(struct ref_lock *lock)
3101 if (commit_lock_file(lock->lk))
3102 return -1;
3103 return 0;
3107 * copy the reflog message msg to buf, which has been allocated sufficiently
3108 * large, while cleaning up the whitespaces. Especially, convert LF to space,
3109 * because reflog file is one line per entry.
3111 static int copy_msg(char *buf, const char *msg)
3113 char *cp = buf;
3114 char c;
3115 int wasspace = 1;
3117 *cp++ = '\t';
3118 while ((c = *msg++)) {
3119 if (wasspace && isspace(c))
3120 continue;
3121 wasspace = isspace(c);
3122 if (wasspace)
3123 c = ' ';
3124 *cp++ = c;
3126 while (buf < cp && isspace(cp[-1]))
3127 cp--;
3128 *cp++ = '\n';
3129 return cp - buf;
3132 static int should_autocreate_reflog(const char *refname)
3134 if (!log_all_ref_updates)
3135 return 0;
3136 return starts_with(refname, "refs/heads/") ||
3137 starts_with(refname, "refs/remotes/") ||
3138 starts_with(refname, "refs/notes/") ||
3139 !strcmp(refname, "HEAD");
3143 * Create a reflog for a ref. If force_create = 0, the reflog will
3144 * only be created for certain refs (those for which
3145 * should_autocreate_reflog returns non-zero. Otherwise, create it
3146 * regardless of the ref name. Fill in *err and return -1 on failure.
3148 static int log_ref_setup(const char *refname, struct strbuf *sb_logfile, struct strbuf *err, int force_create)
3150 int logfd, oflags = O_APPEND | O_WRONLY;
3151 char *logfile;
3153 strbuf_git_path(sb_logfile, "logs/%s", refname);
3154 logfile = sb_logfile->buf;
3155 /* make sure the rest of the function can't change "logfile" */
3156 sb_logfile = NULL;
3157 if (force_create || should_autocreate_reflog(refname)) {
3158 if (safe_create_leading_directories(logfile) < 0) {
3159 strbuf_addf(err, "unable to create directory for %s: "
3160 "%s", logfile, strerror(errno));
3161 return -1;
3163 oflags |= O_CREAT;
3166 logfd = open(logfile, oflags, 0666);
3167 if (logfd < 0) {
3168 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
3169 return 0;
3171 if (errno == EISDIR) {
3172 if (remove_empty_directories(logfile)) {
3173 strbuf_addf(err, "There are still logs under "
3174 "'%s'", logfile);
3175 return -1;
3177 logfd = open(logfile, oflags, 0666);
3180 if (logfd < 0) {
3181 strbuf_addf(err, "unable to append to %s: %s",
3182 logfile, strerror(errno));
3183 return -1;
3187 adjust_shared_perm(logfile);
3188 close(logfd);
3189 return 0;
3193 int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)
3195 int ret;
3196 struct strbuf sb = STRBUF_INIT;
3198 ret = log_ref_setup(refname, &sb, err, force_create);
3199 strbuf_release(&sb);
3200 return ret;
3203 static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
3204 const unsigned char *new_sha1,
3205 const char *committer, const char *msg)
3207 int msglen, written;
3208 unsigned maxlen, len;
3209 char *logrec;
3211 msglen = msg ? strlen(msg) : 0;
3212 maxlen = strlen(committer) + msglen + 100;
3213 logrec = xmalloc(maxlen);
3214 len = sprintf(logrec, "%s %s %s\n",
3215 sha1_to_hex(old_sha1),
3216 sha1_to_hex(new_sha1),
3217 committer);
3218 if (msglen)
3219 len += copy_msg(logrec + len - 1, msg) - 1;
3221 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
3222 free(logrec);
3223 if (written != len)
3224 return -1;
3226 return 0;
3229 static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
3230 const unsigned char *new_sha1, const char *msg,
3231 struct strbuf *sb_log_file, int flags,
3232 struct strbuf *err)
3234 int logfd, result, oflags = O_APPEND | O_WRONLY;
3235 char *log_file;
3237 if (log_all_ref_updates < 0)
3238 log_all_ref_updates = !is_bare_repository();
3240 result = log_ref_setup(refname, sb_log_file, err, flags & REF_FORCE_CREATE_REFLOG);
3242 if (result)
3243 return result;
3244 log_file = sb_log_file->buf;
3245 /* make sure the rest of the function can't change "log_file" */
3246 sb_log_file = NULL;
3248 logfd = open(log_file, oflags);
3249 if (logfd < 0)
3250 return 0;
3251 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
3252 git_committer_info(0), msg);
3253 if (result) {
3254 strbuf_addf(err, "unable to append to %s: %s", log_file,
3255 strerror(errno));
3256 close(logfd);
3257 return -1;
3259 if (close(logfd)) {
3260 strbuf_addf(err, "unable to append to %s: %s", log_file,
3261 strerror(errno));
3262 return -1;
3264 return 0;
3267 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
3268 const unsigned char *new_sha1, const char *msg,
3269 int flags, struct strbuf *err)
3271 struct strbuf sb = STRBUF_INIT;
3272 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
3273 err);
3274 strbuf_release(&sb);
3275 return ret;
3278 int is_branch(const char *refname)
3280 return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
3284 * Write sha1 into the open lockfile, then close the lockfile. On
3285 * errors, rollback the lockfile, fill in *err and
3286 * return -1.
3288 static int write_ref_to_lockfile(struct ref_lock *lock,
3289 const unsigned char *sha1, struct strbuf *err)
3291 static char term = '\n';
3292 struct object *o;
3294 o = parse_object(sha1);
3295 if (!o) {
3296 strbuf_addf(err,
3297 "Trying to write ref %s with nonexistent object %s",
3298 lock->ref_name, sha1_to_hex(sha1));
3299 unlock_ref(lock);
3300 return -1;
3302 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
3303 strbuf_addf(err,
3304 "Trying to write non-commit object %s to branch %s",
3305 sha1_to_hex(sha1), lock->ref_name);
3306 unlock_ref(lock);
3307 return -1;
3309 if (write_in_full(lock->lk->fd, sha1_to_hex(sha1), 40) != 40 ||
3310 write_in_full(lock->lk->fd, &term, 1) != 1 ||
3311 close_ref(lock) < 0) {
3312 strbuf_addf(err,
3313 "Couldn't write %s", lock->lk->filename.buf);
3314 unlock_ref(lock);
3315 return -1;
3317 return 0;
3321 * Commit a change to a loose reference that has already been written
3322 * to the loose reference lockfile. Also update the reflogs if
3323 * necessary, using the specified lockmsg (which can be NULL).
3325 static int commit_ref_update(struct ref_lock *lock,
3326 const unsigned char *sha1, const char *logmsg,
3327 int flags, struct strbuf *err)
3329 clear_loose_ref_cache(&ref_cache);
3330 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0 ||
3331 (strcmp(lock->ref_name, lock->orig_ref_name) &&
3332 log_ref_write(lock->orig_ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0)) {
3333 char *old_msg = strbuf_detach(err, NULL);
3334 strbuf_addf(err, "Cannot update the ref '%s': %s",
3335 lock->ref_name, old_msg);
3336 free(old_msg);
3337 unlock_ref(lock);
3338 return -1;
3340 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
3342 * Special hack: If a branch is updated directly and HEAD
3343 * points to it (may happen on the remote side of a push
3344 * for example) then logically the HEAD reflog should be
3345 * updated too.
3346 * A generic solution implies reverse symref information,
3347 * but finding all symrefs pointing to the given branch
3348 * would be rather costly for this rare event (the direct
3349 * update of a branch) to be worth it. So let's cheat and
3350 * check with HEAD only which should cover 99% of all usage
3351 * scenarios (even 100% of the default ones).
3353 unsigned char head_sha1[20];
3354 int head_flag;
3355 const char *head_ref;
3356 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3357 head_sha1, &head_flag);
3358 if (head_ref && (head_flag & REF_ISSYMREF) &&
3359 !strcmp(head_ref, lock->ref_name)) {
3360 struct strbuf log_err = STRBUF_INIT;
3361 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
3362 logmsg, 0, &log_err)) {
3363 error("%s", log_err.buf);
3364 strbuf_release(&log_err);
3368 if (commit_ref(lock)) {
3369 error("Couldn't set %s", lock->ref_name);
3370 unlock_ref(lock);
3371 return -1;
3374 unlock_ref(lock);
3375 return 0;
3378 int create_symref(const char *ref_target, const char *refs_heads_master,
3379 const char *logmsg)
3381 const char *lockpath;
3382 char ref[1000];
3383 int fd, len, written;
3384 char *git_HEAD = git_pathdup("%s", ref_target);
3385 unsigned char old_sha1[20], new_sha1[20];
3386 struct strbuf err = STRBUF_INIT;
3388 if (logmsg && read_ref(ref_target, old_sha1))
3389 hashclr(old_sha1);
3391 if (safe_create_leading_directories(git_HEAD) < 0)
3392 return error("unable to create directory for %s", git_HEAD);
3394 #ifndef NO_SYMLINK_HEAD
3395 if (prefer_symlink_refs) {
3396 unlink(git_HEAD);
3397 if (!symlink(refs_heads_master, git_HEAD))
3398 goto done;
3399 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
3401 #endif
3403 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
3404 if (sizeof(ref) <= len) {
3405 error("refname too long: %s", refs_heads_master);
3406 goto error_free_return;
3408 lockpath = mkpath("%s.lock", git_HEAD);
3409 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
3410 if (fd < 0) {
3411 error("Unable to open %s for writing", lockpath);
3412 goto error_free_return;
3414 written = write_in_full(fd, ref, len);
3415 if (close(fd) != 0 || written != len) {
3416 error("Unable to write to %s", lockpath);
3417 goto error_unlink_return;
3419 if (rename(lockpath, git_HEAD) < 0) {
3420 error("Unable to create %s", git_HEAD);
3421 goto error_unlink_return;
3423 if (adjust_shared_perm(git_HEAD)) {
3424 error("Unable to fix permissions on %s", lockpath);
3425 error_unlink_return:
3426 unlink_or_warn(lockpath);
3427 error_free_return:
3428 free(git_HEAD);
3429 return -1;
3432 #ifndef NO_SYMLINK_HEAD
3433 done:
3434 #endif
3435 if (logmsg && !read_ref(refs_heads_master, new_sha1) &&
3436 log_ref_write(ref_target, old_sha1, new_sha1, logmsg, 0, &err)) {
3437 error("%s", err.buf);
3438 strbuf_release(&err);
3441 free(git_HEAD);
3442 return 0;
3445 struct read_ref_at_cb {
3446 const char *refname;
3447 unsigned long at_time;
3448 int cnt;
3449 int reccnt;
3450 unsigned char *sha1;
3451 int found_it;
3453 unsigned char osha1[20];
3454 unsigned char nsha1[20];
3455 int tz;
3456 unsigned long date;
3457 char **msg;
3458 unsigned long *cutoff_time;
3459 int *cutoff_tz;
3460 int *cutoff_cnt;
3463 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
3464 const char *email, unsigned long timestamp, int tz,
3465 const char *message, void *cb_data)
3467 struct read_ref_at_cb *cb = cb_data;
3469 cb->reccnt++;
3470 cb->tz = tz;
3471 cb->date = timestamp;
3473 if (timestamp <= cb->at_time || cb->cnt == 0) {
3474 if (cb->msg)
3475 *cb->msg = xstrdup(message);
3476 if (cb->cutoff_time)
3477 *cb->cutoff_time = timestamp;
3478 if (cb->cutoff_tz)
3479 *cb->cutoff_tz = tz;
3480 if (cb->cutoff_cnt)
3481 *cb->cutoff_cnt = cb->reccnt - 1;
3483 * we have not yet updated cb->[n|o]sha1 so they still
3484 * hold the values for the previous record.
3486 if (!is_null_sha1(cb->osha1)) {
3487 hashcpy(cb->sha1, nsha1);
3488 if (hashcmp(cb->osha1, nsha1))
3489 warning("Log for ref %s has gap after %s.",
3490 cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
3492 else if (cb->date == cb->at_time)
3493 hashcpy(cb->sha1, nsha1);
3494 else if (hashcmp(nsha1, cb->sha1))
3495 warning("Log for ref %s unexpectedly ended on %s.",
3496 cb->refname, show_date(cb->date, cb->tz,
3497 DATE_MODE(RFC2822)));
3498 hashcpy(cb->osha1, osha1);
3499 hashcpy(cb->nsha1, nsha1);
3500 cb->found_it = 1;
3501 return 1;
3503 hashcpy(cb->osha1, osha1);
3504 hashcpy(cb->nsha1, nsha1);
3505 if (cb->cnt > 0)
3506 cb->cnt--;
3507 return 0;
3510 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
3511 const char *email, unsigned long timestamp,
3512 int tz, const char *message, void *cb_data)
3514 struct read_ref_at_cb *cb = cb_data;
3516 if (cb->msg)
3517 *cb->msg = xstrdup(message);
3518 if (cb->cutoff_time)
3519 *cb->cutoff_time = timestamp;
3520 if (cb->cutoff_tz)
3521 *cb->cutoff_tz = tz;
3522 if (cb->cutoff_cnt)
3523 *cb->cutoff_cnt = cb->reccnt;
3524 hashcpy(cb->sha1, osha1);
3525 if (is_null_sha1(cb->sha1))
3526 hashcpy(cb->sha1, nsha1);
3527 /* We just want the first entry */
3528 return 1;
3531 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
3532 unsigned char *sha1, char **msg,
3533 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
3535 struct read_ref_at_cb cb;
3537 memset(&cb, 0, sizeof(cb));
3538 cb.refname = refname;
3539 cb.at_time = at_time;
3540 cb.cnt = cnt;
3541 cb.msg = msg;
3542 cb.cutoff_time = cutoff_time;
3543 cb.cutoff_tz = cutoff_tz;
3544 cb.cutoff_cnt = cutoff_cnt;
3545 cb.sha1 = sha1;
3547 for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
3549 if (!cb.reccnt) {
3550 if (flags & GET_SHA1_QUIETLY)
3551 exit(128);
3552 else
3553 die("Log for %s is empty.", refname);
3555 if (cb.found_it)
3556 return 0;
3558 for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
3560 return 1;
3563 int reflog_exists(const char *refname)
3565 struct stat st;
3567 return !lstat(git_path("logs/%s", refname), &st) &&
3568 S_ISREG(st.st_mode);
3571 int delete_reflog(const char *refname)
3573 return remove_path(git_path("logs/%s", refname));
3576 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3578 unsigned char osha1[20], nsha1[20];
3579 char *email_end, *message;
3580 unsigned long timestamp;
3581 int tz;
3583 /* old SP new SP name <email> SP time TAB msg LF */
3584 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3585 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3586 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3587 !(email_end = strchr(sb->buf + 82, '>')) ||
3588 email_end[1] != ' ' ||
3589 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3590 !message || message[0] != ' ' ||
3591 (message[1] != '+' && message[1] != '-') ||
3592 !isdigit(message[2]) || !isdigit(message[3]) ||
3593 !isdigit(message[4]) || !isdigit(message[5]))
3594 return 0; /* corrupt? */
3595 email_end[1] = '\0';
3596 tz = strtol(message + 1, NULL, 10);
3597 if (message[6] != '\t')
3598 message += 6;
3599 else
3600 message += 7;
3601 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3604 static char *find_beginning_of_line(char *bob, char *scan)
3606 while (bob < scan && *(--scan) != '\n')
3607 ; /* keep scanning backwards */
3609 * Return either beginning of the buffer, or LF at the end of
3610 * the previous line.
3612 return scan;
3615 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3617 struct strbuf sb = STRBUF_INIT;
3618 FILE *logfp;
3619 long pos;
3620 int ret = 0, at_tail = 1;
3622 logfp = fopen(git_path("logs/%s", refname), "r");
3623 if (!logfp)
3624 return -1;
3626 /* Jump to the end */
3627 if (fseek(logfp, 0, SEEK_END) < 0)
3628 return error("cannot seek back reflog for %s: %s",
3629 refname, strerror(errno));
3630 pos = ftell(logfp);
3631 while (!ret && 0 < pos) {
3632 int cnt;
3633 size_t nread;
3634 char buf[BUFSIZ];
3635 char *endp, *scanp;
3637 /* Fill next block from the end */
3638 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3639 if (fseek(logfp, pos - cnt, SEEK_SET))
3640 return error("cannot seek back reflog for %s: %s",
3641 refname, strerror(errno));
3642 nread = fread(buf, cnt, 1, logfp);
3643 if (nread != 1)
3644 return error("cannot read %d bytes from reflog for %s: %s",
3645 cnt, refname, strerror(errno));
3646 pos -= cnt;
3648 scanp = endp = buf + cnt;
3649 if (at_tail && scanp[-1] == '\n')
3650 /* Looking at the final LF at the end of the file */
3651 scanp--;
3652 at_tail = 0;
3654 while (buf < scanp) {
3656 * terminating LF of the previous line, or the beginning
3657 * of the buffer.
3659 char *bp;
3661 bp = find_beginning_of_line(buf, scanp);
3663 if (*bp == '\n') {
3665 * The newline is the end of the previous line,
3666 * so we know we have complete line starting
3667 * at (bp + 1). Prefix it onto any prior data
3668 * we collected for the line and process it.
3670 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3671 scanp = bp;
3672 endp = bp + 1;
3673 ret = show_one_reflog_ent(&sb, fn, cb_data);
3674 strbuf_reset(&sb);
3675 if (ret)
3676 break;
3677 } else if (!pos) {
3679 * We are at the start of the buffer, and the
3680 * start of the file; there is no previous
3681 * line, and we have everything for this one.
3682 * Process it, and we can end the loop.
3684 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3685 ret = show_one_reflog_ent(&sb, fn, cb_data);
3686 strbuf_reset(&sb);
3687 break;
3690 if (bp == buf) {
3692 * We are at the start of the buffer, and there
3693 * is more file to read backwards. Which means
3694 * we are in the middle of a line. Note that we
3695 * may get here even if *bp was a newline; that
3696 * just means we are at the exact end of the
3697 * previous line, rather than some spot in the
3698 * middle.
3700 * Save away what we have to be combined with
3701 * the data from the next read.
3703 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3704 break;
3709 if (!ret && sb.len)
3710 die("BUG: reverse reflog parser had leftover data");
3712 fclose(logfp);
3713 strbuf_release(&sb);
3714 return ret;
3717 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3719 FILE *logfp;
3720 struct strbuf sb = STRBUF_INIT;
3721 int ret = 0;
3723 logfp = fopen(git_path("logs/%s", refname), "r");
3724 if (!logfp)
3725 return -1;
3727 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3728 ret = show_one_reflog_ent(&sb, fn, cb_data);
3729 fclose(logfp);
3730 strbuf_release(&sb);
3731 return ret;
3734 * Call fn for each reflog in the namespace indicated by name. name
3735 * must be empty or end with '/'. Name will be used as a scratch
3736 * space, but its contents will be restored before return.
3738 static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3740 DIR *d = opendir(git_path("logs/%s", name->buf));
3741 int retval = 0;
3742 struct dirent *de;
3743 int oldlen = name->len;
3745 if (!d)
3746 return name->len ? errno : 0;
3748 while ((de = readdir(d)) != NULL) {
3749 struct stat st;
3751 if (de->d_name[0] == '.')
3752 continue;
3753 if (ends_with(de->d_name, ".lock"))
3754 continue;
3755 strbuf_addstr(name, de->d_name);
3756 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3757 ; /* silently ignore */
3758 } else {
3759 if (S_ISDIR(st.st_mode)) {
3760 strbuf_addch(name, '/');
3761 retval = do_for_each_reflog(name, fn, cb_data);
3762 } else {
3763 struct object_id oid;
3765 if (read_ref_full(name->buf, 0, oid.hash, NULL))
3766 retval = error("bad ref for %s", name->buf);
3767 else
3768 retval = fn(name->buf, &oid, 0, cb_data);
3770 if (retval)
3771 break;
3773 strbuf_setlen(name, oldlen);
3775 closedir(d);
3776 return retval;
3779 int for_each_reflog(each_ref_fn fn, void *cb_data)
3781 int retval;
3782 struct strbuf name;
3783 strbuf_init(&name, PATH_MAX);
3784 retval = do_for_each_reflog(&name, fn, cb_data);
3785 strbuf_release(&name);
3786 return retval;
3790 * Information needed for a single ref update. Set new_sha1 to the new
3791 * value or to null_sha1 to delete the ref. To check the old value
3792 * while the ref is locked, set (flags & REF_HAVE_OLD) and set
3793 * old_sha1 to the old value, or to null_sha1 to ensure the ref does
3794 * not exist before update.
3796 struct ref_update {
3798 * If (flags & REF_HAVE_NEW), set the reference to this value:
3800 unsigned char new_sha1[20];
3802 * If (flags & REF_HAVE_OLD), check that the reference
3803 * previously had this value:
3805 unsigned char old_sha1[20];
3807 * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
3808 * REF_DELETING, and REF_ISPRUNING:
3810 unsigned int flags;
3811 struct ref_lock *lock;
3812 int type;
3813 char *msg;
3814 const char refname[FLEX_ARRAY];
3818 * Transaction states.
3819 * OPEN: The transaction is in a valid state and can accept new updates.
3820 * An OPEN transaction can be committed.
3821 * CLOSED: A closed transaction is no longer active and no other operations
3822 * than free can be used on it in this state.
3823 * A transaction can either become closed by successfully committing
3824 * an active transaction or if there is a failure while building
3825 * the transaction thus rendering it failed/inactive.
3827 enum ref_transaction_state {
3828 REF_TRANSACTION_OPEN = 0,
3829 REF_TRANSACTION_CLOSED = 1
3833 * Data structure for holding a reference transaction, which can
3834 * consist of checks and updates to multiple references, carried out
3835 * as atomically as possible. This structure is opaque to callers.
3837 struct ref_transaction {
3838 struct ref_update **updates;
3839 size_t alloc;
3840 size_t nr;
3841 enum ref_transaction_state state;
3844 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
3846 assert(err);
3848 return xcalloc(1, sizeof(struct ref_transaction));
3851 void ref_transaction_free(struct ref_transaction *transaction)
3853 int i;
3855 if (!transaction)
3856 return;
3858 for (i = 0; i < transaction->nr; i++) {
3859 free(transaction->updates[i]->msg);
3860 free(transaction->updates[i]);
3862 free(transaction->updates);
3863 free(transaction);
3866 static struct ref_update *add_update(struct ref_transaction *transaction,
3867 const char *refname)
3869 size_t len = strlen(refname);
3870 struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
3872 strcpy((char *)update->refname, refname);
3873 ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
3874 transaction->updates[transaction->nr++] = update;
3875 return update;
3878 int ref_transaction_update(struct ref_transaction *transaction,
3879 const char *refname,
3880 const unsigned char *new_sha1,
3881 const unsigned char *old_sha1,
3882 unsigned int flags, const char *msg,
3883 struct strbuf *err)
3885 struct ref_update *update;
3887 assert(err);
3889 if (transaction->state != REF_TRANSACTION_OPEN)
3890 die("BUG: update called for transaction that is not open");
3892 if (new_sha1 && !is_null_sha1(new_sha1) &&
3893 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
3894 strbuf_addf(err, "refusing to update ref with bad name %s",
3895 refname);
3896 return -1;
3899 update = add_update(transaction, refname);
3900 if (new_sha1) {
3901 hashcpy(update->new_sha1, new_sha1);
3902 flags |= REF_HAVE_NEW;
3904 if (old_sha1) {
3905 hashcpy(update->old_sha1, old_sha1);
3906 flags |= REF_HAVE_OLD;
3908 update->flags = flags;
3909 if (msg)
3910 update->msg = xstrdup(msg);
3911 return 0;
3914 int ref_transaction_create(struct ref_transaction *transaction,
3915 const char *refname,
3916 const unsigned char *new_sha1,
3917 unsigned int flags, const char *msg,
3918 struct strbuf *err)
3920 if (!new_sha1 || is_null_sha1(new_sha1))
3921 die("BUG: create called without valid new_sha1");
3922 return ref_transaction_update(transaction, refname, new_sha1,
3923 null_sha1, flags, msg, err);
3926 int ref_transaction_delete(struct ref_transaction *transaction,
3927 const char *refname,
3928 const unsigned char *old_sha1,
3929 unsigned int flags, const char *msg,
3930 struct strbuf *err)
3932 if (old_sha1 && is_null_sha1(old_sha1))
3933 die("BUG: delete called with old_sha1 set to zeros");
3934 return ref_transaction_update(transaction, refname,
3935 null_sha1, old_sha1,
3936 flags, msg, err);
3939 int ref_transaction_verify(struct ref_transaction *transaction,
3940 const char *refname,
3941 const unsigned char *old_sha1,
3942 unsigned int flags,
3943 struct strbuf *err)
3945 if (!old_sha1)
3946 die("BUG: verify called with old_sha1 set to NULL");
3947 return ref_transaction_update(transaction, refname,
3948 NULL, old_sha1,
3949 flags, NULL, err);
3952 int update_ref(const char *msg, const char *refname,
3953 const unsigned char *new_sha1, const unsigned char *old_sha1,
3954 unsigned int flags, enum action_on_err onerr)
3956 struct ref_transaction *t;
3957 struct strbuf err = STRBUF_INIT;
3959 t = ref_transaction_begin(&err);
3960 if (!t ||
3961 ref_transaction_update(t, refname, new_sha1, old_sha1,
3962 flags, msg, &err) ||
3963 ref_transaction_commit(t, &err)) {
3964 const char *str = "update_ref failed for ref '%s': %s";
3966 ref_transaction_free(t);
3967 switch (onerr) {
3968 case UPDATE_REFS_MSG_ON_ERR:
3969 error(str, refname, err.buf);
3970 break;
3971 case UPDATE_REFS_DIE_ON_ERR:
3972 die(str, refname, err.buf);
3973 break;
3974 case UPDATE_REFS_QUIET_ON_ERR:
3975 break;
3977 strbuf_release(&err);
3978 return 1;
3980 strbuf_release(&err);
3981 ref_transaction_free(t);
3982 return 0;
3985 static int ref_update_reject_duplicates(struct string_list *refnames,
3986 struct strbuf *err)
3988 int i, n = refnames->nr;
3990 assert(err);
3992 for (i = 1; i < n; i++)
3993 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3994 strbuf_addf(err,
3995 "Multiple updates for ref '%s' not allowed.",
3996 refnames->items[i].string);
3997 return 1;
3999 return 0;
4002 int ref_transaction_commit(struct ref_transaction *transaction,
4003 struct strbuf *err)
4005 int ret = 0, i;
4006 int n = transaction->nr;
4007 struct ref_update **updates = transaction->updates;
4008 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
4009 struct string_list_item *ref_to_delete;
4010 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
4012 assert(err);
4014 if (transaction->state != REF_TRANSACTION_OPEN)
4015 die("BUG: commit called for transaction that is not open");
4017 if (!n) {
4018 transaction->state = REF_TRANSACTION_CLOSED;
4019 return 0;
4022 /* Fail if a refname appears more than once in the transaction: */
4023 for (i = 0; i < n; i++)
4024 string_list_append(&affected_refnames, updates[i]->refname);
4025 string_list_sort(&affected_refnames);
4026 if (ref_update_reject_duplicates(&affected_refnames, err)) {
4027 ret = TRANSACTION_GENERIC_ERROR;
4028 goto cleanup;
4032 * Acquire all locks, verify old values if provided, check
4033 * that new values are valid, and write new values to the
4034 * lockfiles, ready to be activated. Only keep one lockfile
4035 * open at a time to avoid running out of file descriptors.
4037 for (i = 0; i < n; i++) {
4038 struct ref_update *update = updates[i];
4040 if ((update->flags & REF_HAVE_NEW) &&
4041 is_null_sha1(update->new_sha1))
4042 update->flags |= REF_DELETING;
4043 update->lock = lock_ref_sha1_basic(
4044 update->refname,
4045 ((update->flags & REF_HAVE_OLD) ?
4046 update->old_sha1 : NULL),
4047 &affected_refnames, NULL,
4048 update->flags,
4049 &update->type,
4050 err);
4051 if (!update->lock) {
4052 char *reason;
4054 ret = (errno == ENOTDIR)
4055 ? TRANSACTION_NAME_CONFLICT
4056 : TRANSACTION_GENERIC_ERROR;
4057 reason = strbuf_detach(err, NULL);
4058 strbuf_addf(err, "cannot lock ref '%s': %s",
4059 update->refname, reason);
4060 free(reason);
4061 goto cleanup;
4063 if ((update->flags & REF_HAVE_NEW) &&
4064 !(update->flags & REF_DELETING)) {
4065 int overwriting_symref = ((update->type & REF_ISSYMREF) &&
4066 (update->flags & REF_NODEREF));
4068 if (!overwriting_symref &&
4069 !hashcmp(update->lock->old_oid.hash, update->new_sha1)) {
4071 * The reference already has the desired
4072 * value, so we don't need to write it.
4074 } else if (write_ref_to_lockfile(update->lock,
4075 update->new_sha1,
4076 err)) {
4077 char *write_err = strbuf_detach(err, NULL);
4080 * The lock was freed upon failure of
4081 * write_ref_to_lockfile():
4083 update->lock = NULL;
4084 strbuf_addf(err,
4085 "cannot update the ref '%s': %s",
4086 update->refname, write_err);
4087 free(write_err);
4088 ret = TRANSACTION_GENERIC_ERROR;
4089 goto cleanup;
4090 } else {
4091 update->flags |= REF_NEEDS_COMMIT;
4094 if (!(update->flags & REF_NEEDS_COMMIT)) {
4096 * We didn't have to write anything to the lockfile.
4097 * Close it to free up the file descriptor:
4099 if (close_ref(update->lock)) {
4100 strbuf_addf(err, "Couldn't close %s.lock",
4101 update->refname);
4102 goto cleanup;
4107 /* Perform updates first so live commits remain referenced */
4108 for (i = 0; i < n; i++) {
4109 struct ref_update *update = updates[i];
4111 if (update->flags & REF_NEEDS_COMMIT) {
4112 if (commit_ref_update(update->lock,
4113 update->new_sha1, update->msg,
4114 update->flags, err)) {
4115 /* freed by commit_ref_update(): */
4116 update->lock = NULL;
4117 ret = TRANSACTION_GENERIC_ERROR;
4118 goto cleanup;
4119 } else {
4120 /* freed by commit_ref_update(): */
4121 update->lock = NULL;
4126 /* Perform deletes now that updates are safely completed */
4127 for (i = 0; i < n; i++) {
4128 struct ref_update *update = updates[i];
4130 if (update->flags & REF_DELETING) {
4131 if (delete_ref_loose(update->lock, update->type, err)) {
4132 ret = TRANSACTION_GENERIC_ERROR;
4133 goto cleanup;
4136 if (!(update->flags & REF_ISPRUNING))
4137 string_list_append(&refs_to_delete,
4138 update->lock->ref_name);
4142 if (repack_without_refs(&refs_to_delete, err)) {
4143 ret = TRANSACTION_GENERIC_ERROR;
4144 goto cleanup;
4146 for_each_string_list_item(ref_to_delete, &refs_to_delete)
4147 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
4148 clear_loose_ref_cache(&ref_cache);
4150 cleanup:
4151 transaction->state = REF_TRANSACTION_CLOSED;
4153 for (i = 0; i < n; i++)
4154 if (updates[i]->lock)
4155 unlock_ref(updates[i]->lock);
4156 string_list_clear(&refs_to_delete, 0);
4157 string_list_clear(&affected_refnames, 0);
4158 return ret;
4161 static int ref_present(const char *refname,
4162 const struct object_id *oid, int flags, void *cb_data)
4164 struct string_list *affected_refnames = cb_data;
4166 return string_list_has_string(affected_refnames, refname);
4169 int initial_ref_transaction_commit(struct ref_transaction *transaction,
4170 struct strbuf *err)
4172 struct ref_dir *loose_refs = get_loose_refs(&ref_cache);
4173 struct ref_dir *packed_refs = get_packed_refs(&ref_cache);
4174 int ret = 0, i;
4175 int n = transaction->nr;
4176 struct ref_update **updates = transaction->updates;
4177 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
4179 assert(err);
4181 if (transaction->state != REF_TRANSACTION_OPEN)
4182 die("BUG: commit called for transaction that is not open");
4184 /* Fail if a refname appears more than once in the transaction: */
4185 for (i = 0; i < n; i++)
4186 string_list_append(&affected_refnames, updates[i]->refname);
4187 string_list_sort(&affected_refnames);
4188 if (ref_update_reject_duplicates(&affected_refnames, err)) {
4189 ret = TRANSACTION_GENERIC_ERROR;
4190 goto cleanup;
4194 * It's really undefined to call this function in an active
4195 * repository or when there are existing references: we are
4196 * only locking and changing packed-refs, so (1) any
4197 * simultaneous processes might try to change a reference at
4198 * the same time we do, and (2) any existing loose versions of
4199 * the references that we are setting would have precedence
4200 * over our values. But some remote helpers create the remote
4201 * "HEAD" and "master" branches before calling this function,
4202 * so here we really only check that none of the references
4203 * that we are creating already exists.
4205 if (for_each_rawref(ref_present, &affected_refnames))
4206 die("BUG: initial ref transaction called with existing refs");
4208 for (i = 0; i < n; i++) {
4209 struct ref_update *update = updates[i];
4211 if ((update->flags & REF_HAVE_OLD) &&
4212 !is_null_sha1(update->old_sha1))
4213 die("BUG: initial ref transaction with old_sha1 set");
4214 if (verify_refname_available(update->refname,
4215 &affected_refnames, NULL,
4216 loose_refs, err) ||
4217 verify_refname_available(update->refname,
4218 &affected_refnames, NULL,
4219 packed_refs, err)) {
4220 ret = TRANSACTION_NAME_CONFLICT;
4221 goto cleanup;
4225 if (lock_packed_refs(0)) {
4226 strbuf_addf(err, "unable to lock packed-refs file: %s",
4227 strerror(errno));
4228 ret = TRANSACTION_GENERIC_ERROR;
4229 goto cleanup;
4232 for (i = 0; i < n; i++) {
4233 struct ref_update *update = updates[i];
4235 if ((update->flags & REF_HAVE_NEW) &&
4236 !is_null_sha1(update->new_sha1))
4237 add_packed_ref(update->refname, update->new_sha1);
4240 if (commit_packed_refs()) {
4241 strbuf_addf(err, "unable to commit packed-refs file: %s",
4242 strerror(errno));
4243 ret = TRANSACTION_GENERIC_ERROR;
4244 goto cleanup;
4247 cleanup:
4248 transaction->state = REF_TRANSACTION_CLOSED;
4249 string_list_clear(&affected_refnames, 0);
4250 return ret;
4253 char *shorten_unambiguous_ref(const char *refname, int strict)
4255 int i;
4256 static char **scanf_fmts;
4257 static int nr_rules;
4258 char *short_name;
4260 if (!nr_rules) {
4262 * Pre-generate scanf formats from ref_rev_parse_rules[].
4263 * Generate a format suitable for scanf from a
4264 * ref_rev_parse_rules rule by interpolating "%s" at the
4265 * location of the "%.*s".
4267 size_t total_len = 0;
4268 size_t offset = 0;
4270 /* the rule list is NULL terminated, count them first */
4271 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
4272 /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
4273 total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
4275 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
4277 offset = 0;
4278 for (i = 0; i < nr_rules; i++) {
4279 assert(offset < total_len);
4280 scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
4281 offset += snprintf(scanf_fmts[i], total_len - offset,
4282 ref_rev_parse_rules[i], 2, "%s") + 1;
4286 /* bail out if there are no rules */
4287 if (!nr_rules)
4288 return xstrdup(refname);
4290 /* buffer for scanf result, at most refname must fit */
4291 short_name = xstrdup(refname);
4293 /* skip first rule, it will always match */
4294 for (i = nr_rules - 1; i > 0 ; --i) {
4295 int j;
4296 int rules_to_fail = i;
4297 int short_name_len;
4299 if (1 != sscanf(refname, scanf_fmts[i], short_name))
4300 continue;
4302 short_name_len = strlen(short_name);
4305 * in strict mode, all (except the matched one) rules
4306 * must fail to resolve to a valid non-ambiguous ref
4308 if (strict)
4309 rules_to_fail = nr_rules;
4312 * check if the short name resolves to a valid ref,
4313 * but use only rules prior to the matched one
4315 for (j = 0; j < rules_to_fail; j++) {
4316 const char *rule = ref_rev_parse_rules[j];
4317 char refname[PATH_MAX];
4319 /* skip matched rule */
4320 if (i == j)
4321 continue;
4324 * the short name is ambiguous, if it resolves
4325 * (with this previous rule) to a valid ref
4326 * read_ref() returns 0 on success
4328 mksnpath(refname, sizeof(refname),
4329 rule, short_name_len, short_name);
4330 if (ref_exists(refname))
4331 break;
4335 * short name is non-ambiguous if all previous rules
4336 * haven't resolved to a valid ref
4338 if (j == rules_to_fail)
4339 return short_name;
4342 free(short_name);
4343 return xstrdup(refname);
4346 static struct string_list *hide_refs;
4348 int parse_hide_refs_config(const char *var, const char *value, const char *section)
4350 if (!strcmp("transfer.hiderefs", var) ||
4351 /* NEEDSWORK: use parse_config_key() once both are merged */
4352 (starts_with(var, section) && var[strlen(section)] == '.' &&
4353 !strcmp(var + strlen(section), ".hiderefs"))) {
4354 char *ref;
4355 int len;
4357 if (!value)
4358 return config_error_nonbool(var);
4359 ref = xstrdup(value);
4360 len = strlen(ref);
4361 while (len && ref[len - 1] == '/')
4362 ref[--len] = '\0';
4363 if (!hide_refs) {
4364 hide_refs = xcalloc(1, sizeof(*hide_refs));
4365 hide_refs->strdup_strings = 1;
4367 string_list_append(hide_refs, ref);
4369 return 0;
4372 int ref_is_hidden(const char *refname)
4374 struct string_list_item *item;
4376 if (!hide_refs)
4377 return 0;
4378 for_each_string_list_item(item, hide_refs) {
4379 int len;
4380 if (!starts_with(refname, item->string))
4381 continue;
4382 len = strlen(item->string);
4383 if (!refname[len] || refname[len] == '/')
4384 return 1;
4386 return 0;
4389 struct expire_reflog_cb {
4390 unsigned int flags;
4391 reflog_expiry_should_prune_fn *should_prune_fn;
4392 void *policy_cb;
4393 FILE *newlog;
4394 unsigned char last_kept_sha1[20];
4397 static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
4398 const char *email, unsigned long timestamp, int tz,
4399 const char *message, void *cb_data)
4401 struct expire_reflog_cb *cb = cb_data;
4402 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
4404 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
4405 osha1 = cb->last_kept_sha1;
4407 if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,
4408 message, policy_cb)) {
4409 if (!cb->newlog)
4410 printf("would prune %s", message);
4411 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
4412 printf("prune %s", message);
4413 } else {
4414 if (cb->newlog) {
4415 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
4416 sha1_to_hex(osha1), sha1_to_hex(nsha1),
4417 email, timestamp, tz, message);
4418 hashcpy(cb->last_kept_sha1, nsha1);
4420 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
4421 printf("keep %s", message);
4423 return 0;
4426 int reflog_expire(const char *refname, const unsigned char *sha1,
4427 unsigned int flags,
4428 reflog_expiry_prepare_fn prepare_fn,
4429 reflog_expiry_should_prune_fn should_prune_fn,
4430 reflog_expiry_cleanup_fn cleanup_fn,
4431 void *policy_cb_data)
4433 static struct lock_file reflog_lock;
4434 struct expire_reflog_cb cb;
4435 struct ref_lock *lock;
4436 char *log_file;
4437 int status = 0;
4438 int type;
4439 struct strbuf err = STRBUF_INIT;
4441 memset(&cb, 0, sizeof(cb));
4442 cb.flags = flags;
4443 cb.policy_cb = policy_cb_data;
4444 cb.should_prune_fn = should_prune_fn;
4447 * The reflog file is locked by holding the lock on the
4448 * reference itself, plus we might need to update the
4449 * reference if --updateref was specified:
4451 lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, 0, &type, &err);
4452 if (!lock) {
4453 error("cannot lock ref '%s': %s", refname, err.buf);
4454 strbuf_release(&err);
4455 return -1;
4457 if (!reflog_exists(refname)) {
4458 unlock_ref(lock);
4459 return 0;
4462 log_file = git_pathdup("logs/%s", refname);
4463 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
4465 * Even though holding $GIT_DIR/logs/$reflog.lock has
4466 * no locking implications, we use the lock_file
4467 * machinery here anyway because it does a lot of the
4468 * work we need, including cleaning up if the program
4469 * exits unexpectedly.
4471 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
4472 struct strbuf err = STRBUF_INIT;
4473 unable_to_lock_message(log_file, errno, &err);
4474 error("%s", err.buf);
4475 strbuf_release(&err);
4476 goto failure;
4478 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
4479 if (!cb.newlog) {
4480 error("cannot fdopen %s (%s)",
4481 reflog_lock.filename.buf, strerror(errno));
4482 goto failure;
4486 (*prepare_fn)(refname, sha1, cb.policy_cb);
4487 for_each_reflog_ent(refname, expire_reflog_ent, &cb);
4488 (*cleanup_fn)(cb.policy_cb);
4490 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
4492 * It doesn't make sense to adjust a reference pointed
4493 * to by a symbolic ref based on expiring entries in
4494 * the symbolic reference's reflog. Nor can we update
4495 * a reference if there are no remaining reflog
4496 * entries.
4498 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
4499 !(type & REF_ISSYMREF) &&
4500 !is_null_sha1(cb.last_kept_sha1);
4502 if (close_lock_file(&reflog_lock)) {
4503 status |= error("couldn't write %s: %s", log_file,
4504 strerror(errno));
4505 } else if (update &&
4506 (write_in_full(lock->lk->fd,
4507 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
4508 write_str_in_full(lock->lk->fd, "\n") != 1 ||
4509 close_ref(lock) < 0)) {
4510 status |= error("couldn't write %s",
4511 lock->lk->filename.buf);
4512 rollback_lock_file(&reflog_lock);
4513 } else if (commit_lock_file(&reflog_lock)) {
4514 status |= error("unable to commit reflog '%s' (%s)",
4515 log_file, strerror(errno));
4516 } else if (update && commit_ref(lock)) {
4517 status |= error("couldn't set %s", lock->ref_name);
4520 free(log_file);
4521 unlock_ref(lock);
4522 return status;
4524 failure:
4525 rollback_lock_file(&reflog_lock);
4526 free(log_file);
4527 unlock_ref(lock);
4528 return -1;