Merge branch 'jk/test-annoyances'
[git/mingw.git] / refs.c
blobe23542b3869b38e47f59f102d28648d30d506574
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 unsigned char old_sha1[20];
14 int lock_fd;
18 * How to handle various characters in refnames:
19 * 0: An acceptable character for refs
20 * 1: End-of-component
21 * 2: ., look for a preceding . to reject .. in refs
22 * 3: {, look for a preceding @ to reject @{ in refs
23 * 4: A bad character: ASCII control characters, "~", "^", ":" or SP
25 static unsigned char refname_disposition[256] = {
26 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
27 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
28 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 2, 1,
29 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
30 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
31 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
32 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
33 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
37 * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
38 * refs (i.e., because the reference is about to be deleted anyway).
40 #define REF_DELETING 0x02
43 * Used as a flag in ref_update::flags when a loose ref is being
44 * pruned.
46 #define REF_ISPRUNING 0x04
49 * Used as a flag in ref_update::flags when the reference should be
50 * updated to new_sha1.
52 #define REF_HAVE_NEW 0x08
55 * Used as a flag in ref_update::flags when old_sha1 should be
56 * checked.
58 #define REF_HAVE_OLD 0x10
61 * Try to read one refname component from the front of refname.
62 * Return the length of the component found, or -1 if the component is
63 * not legal. It is legal if it is something reasonable to have under
64 * ".git/refs/"; We do not like it if:
66 * - any path component of it begins with ".", or
67 * - it has double dots "..", or
68 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
69 * - it ends with a "/".
70 * - it ends with ".lock"
71 * - it contains a "\" (backslash)
73 static int check_refname_component(const char *refname, int flags)
75 const char *cp;
76 char last = '\0';
78 for (cp = refname; ; cp++) {
79 int ch = *cp & 255;
80 unsigned char disp = refname_disposition[ch];
81 switch (disp) {
82 case 1:
83 goto out;
84 case 2:
85 if (last == '.')
86 return -1; /* Refname contains "..". */
87 break;
88 case 3:
89 if (last == '@')
90 return -1; /* Refname contains "@{". */
91 break;
92 case 4:
93 return -1;
95 last = ch;
97 out:
98 if (cp == refname)
99 return 0; /* Component has zero length. */
100 if (refname[0] == '.')
101 return -1; /* Component starts with '.'. */
102 if (cp - refname >= LOCK_SUFFIX_LEN &&
103 !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
104 return -1; /* Refname ends with ".lock". */
105 return cp - refname;
108 int check_refname_format(const char *refname, int flags)
110 int component_len, component_count = 0;
112 if (!strcmp(refname, "@"))
113 /* Refname is a single character '@'. */
114 return -1;
116 while (1) {
117 /* We are at the start of a path component. */
118 component_len = check_refname_component(refname, flags);
119 if (component_len <= 0) {
120 if ((flags & REFNAME_REFSPEC_PATTERN) &&
121 refname[0] == '*' &&
122 (refname[1] == '\0' || refname[1] == '/')) {
123 /* Accept one wildcard as a full refname component. */
124 flags &= ~REFNAME_REFSPEC_PATTERN;
125 component_len = 1;
126 } else {
127 return -1;
130 component_count++;
131 if (refname[component_len] == '\0')
132 break;
133 /* Skip to next component. */
134 refname += component_len + 1;
137 if (refname[component_len - 1] == '.')
138 return -1; /* Refname ends with '.'. */
139 if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
140 return -1; /* Refname has only one component. */
141 return 0;
144 struct ref_entry;
147 * Information used (along with the information in ref_entry) to
148 * describe a single cached reference. This data structure only
149 * occurs embedded in a union in struct ref_entry, and only when
150 * (ref_entry->flag & REF_DIR) is zero.
152 struct ref_value {
154 * The name of the object to which this reference resolves
155 * (which may be a tag object). If REF_ISBROKEN, this is
156 * null. If REF_ISSYMREF, then this is the name of the object
157 * referred to by the last reference in the symlink chain.
159 unsigned char sha1[20];
162 * If REF_KNOWS_PEELED, then this field holds the peeled value
163 * of this reference, or null if the reference is known not to
164 * be peelable. See the documentation for peel_ref() for an
165 * exact definition of "peelable".
167 unsigned char peeled[20];
170 struct ref_cache;
173 * Information used (along with the information in ref_entry) to
174 * describe a level in the hierarchy of references. This data
175 * structure only occurs embedded in a union in struct ref_entry, and
176 * only when (ref_entry.flag & REF_DIR) is set. In that case,
177 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
178 * in the directory have already been read:
180 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
181 * or packed references, already read.
183 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
184 * references that hasn't been read yet (nor has any of its
185 * subdirectories).
187 * Entries within a directory are stored within a growable array of
188 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
189 * sorted are sorted by their component name in strcmp() order and the
190 * remaining entries are unsorted.
192 * Loose references are read lazily, one directory at a time. When a
193 * directory of loose references is read, then all of the references
194 * in that directory are stored, and REF_INCOMPLETE stubs are created
195 * for any subdirectories, but the subdirectories themselves are not
196 * read. The reading is triggered by get_ref_dir().
198 struct ref_dir {
199 int nr, alloc;
202 * Entries with index 0 <= i < sorted are sorted by name. New
203 * entries are appended to the list unsorted, and are sorted
204 * only when required; thus we avoid the need to sort the list
205 * after the addition of every reference.
207 int sorted;
209 /* A pointer to the ref_cache that contains this ref_dir. */
210 struct ref_cache *ref_cache;
212 struct ref_entry **entries;
216 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
217 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
218 * public values; see refs.h.
222 * The field ref_entry->u.value.peeled of this value entry contains
223 * the correct peeled value for the reference, which might be
224 * null_sha1 if the reference is not a tag or if it is broken.
226 #define REF_KNOWS_PEELED 0x10
228 /* ref_entry represents a directory of references */
229 #define REF_DIR 0x20
232 * Entry has not yet been read from disk (used only for REF_DIR
233 * entries representing loose references)
235 #define REF_INCOMPLETE 0x40
238 * A ref_entry represents either a reference or a "subdirectory" of
239 * references.
241 * Each directory in the reference namespace is represented by a
242 * ref_entry with (flags & REF_DIR) set and containing a subdir member
243 * that holds the entries in that directory that have been read so
244 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
245 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
246 * used for loose reference directories.
248 * References are represented by a ref_entry with (flags & REF_DIR)
249 * unset and a value member that describes the reference's value. The
250 * flag member is at the ref_entry level, but it is also needed to
251 * interpret the contents of the value field (in other words, a
252 * ref_value object is not very much use without the enclosing
253 * ref_entry).
255 * Reference names cannot end with slash and directories' names are
256 * always stored with a trailing slash (except for the top-level
257 * directory, which is always denoted by ""). This has two nice
258 * consequences: (1) when the entries in each subdir are sorted
259 * lexicographically by name (as they usually are), the references in
260 * a whole tree can be generated in lexicographic order by traversing
261 * the tree in left-to-right, depth-first order; (2) the names of
262 * references and subdirectories cannot conflict, and therefore the
263 * presence of an empty subdirectory does not block the creation of a
264 * similarly-named reference. (The fact that reference names with the
265 * same leading components can conflict *with each other* is a
266 * separate issue that is regulated by is_refname_available().)
268 * Please note that the name field contains the fully-qualified
269 * reference (or subdirectory) name. Space could be saved by only
270 * storing the relative names. But that would require the full names
271 * to be generated on the fly when iterating in do_for_each_ref(), and
272 * would break callback functions, who have always been able to assume
273 * that the name strings that they are passed will not be freed during
274 * the iteration.
276 struct ref_entry {
277 unsigned char flag; /* ISSYMREF? ISPACKED? */
278 union {
279 struct ref_value value; /* if not (flags&REF_DIR) */
280 struct ref_dir subdir; /* if (flags&REF_DIR) */
281 } u;
283 * The full name of the reference (e.g., "refs/heads/master")
284 * or the full name of the directory with a trailing slash
285 * (e.g., "refs/heads/"):
287 char name[FLEX_ARRAY];
290 static void read_loose_refs(const char *dirname, struct ref_dir *dir);
292 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
294 struct ref_dir *dir;
295 assert(entry->flag & REF_DIR);
296 dir = &entry->u.subdir;
297 if (entry->flag & REF_INCOMPLETE) {
298 read_loose_refs(entry->name, dir);
299 entry->flag &= ~REF_INCOMPLETE;
301 return dir;
305 * Check if a refname is safe.
306 * For refs that start with "refs/" we consider it safe as long they do
307 * not try to resolve to outside of refs/.
309 * For all other refs we only consider them safe iff they only contain
310 * upper case characters and '_' (like "HEAD" AND "MERGE_HEAD", and not like
311 * "config").
313 static int refname_is_safe(const char *refname)
315 if (starts_with(refname, "refs/")) {
316 char *buf;
317 int result;
319 buf = xmalloc(strlen(refname) + 1);
321 * Does the refname try to escape refs/?
322 * For example: refs/foo/../bar is safe but refs/foo/../../bar
323 * is not.
325 result = !normalize_path_copy(buf, refname + strlen("refs/"));
326 free(buf);
327 return result;
329 while (*refname) {
330 if (!isupper(*refname) && *refname != '_')
331 return 0;
332 refname++;
334 return 1;
337 static struct ref_entry *create_ref_entry(const char *refname,
338 const unsigned char *sha1, int flag,
339 int check_name)
341 int len;
342 struct ref_entry *ref;
344 if (check_name &&
345 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
346 die("Reference has invalid format: '%s'", refname);
347 if (!check_name && !refname_is_safe(refname))
348 die("Reference has invalid name: '%s'", refname);
349 len = strlen(refname) + 1;
350 ref = xmalloc(sizeof(struct ref_entry) + len);
351 hashcpy(ref->u.value.sha1, sha1);
352 hashclr(ref->u.value.peeled);
353 memcpy(ref->name, refname, len);
354 ref->flag = flag;
355 return ref;
358 static void clear_ref_dir(struct ref_dir *dir);
360 static void free_ref_entry(struct ref_entry *entry)
362 if (entry->flag & REF_DIR) {
364 * Do not use get_ref_dir() here, as that might
365 * trigger the reading of loose refs.
367 clear_ref_dir(&entry->u.subdir);
369 free(entry);
373 * Add a ref_entry to the end of dir (unsorted). Entry is always
374 * stored directly in dir; no recursion into subdirectories is
375 * done.
377 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
379 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
380 dir->entries[dir->nr++] = entry;
381 /* optimize for the case that entries are added in order */
382 if (dir->nr == 1 ||
383 (dir->nr == dir->sorted + 1 &&
384 strcmp(dir->entries[dir->nr - 2]->name,
385 dir->entries[dir->nr - 1]->name) < 0))
386 dir->sorted = dir->nr;
390 * Clear and free all entries in dir, recursively.
392 static void clear_ref_dir(struct ref_dir *dir)
394 int i;
395 for (i = 0; i < dir->nr; i++)
396 free_ref_entry(dir->entries[i]);
397 free(dir->entries);
398 dir->sorted = dir->nr = dir->alloc = 0;
399 dir->entries = NULL;
403 * Create a struct ref_entry object for the specified dirname.
404 * dirname is the name of the directory with a trailing slash (e.g.,
405 * "refs/heads/") or "" for the top-level directory.
407 static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
408 const char *dirname, size_t len,
409 int incomplete)
411 struct ref_entry *direntry;
412 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
413 memcpy(direntry->name, dirname, len);
414 direntry->name[len] = '\0';
415 direntry->u.subdir.ref_cache = ref_cache;
416 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
417 return direntry;
420 static int ref_entry_cmp(const void *a, const void *b)
422 struct ref_entry *one = *(struct ref_entry **)a;
423 struct ref_entry *two = *(struct ref_entry **)b;
424 return strcmp(one->name, two->name);
427 static void sort_ref_dir(struct ref_dir *dir);
429 struct string_slice {
430 size_t len;
431 const char *str;
434 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
436 const struct string_slice *key = key_;
437 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
438 int cmp = strncmp(key->str, ent->name, key->len);
439 if (cmp)
440 return cmp;
441 return '\0' - (unsigned char)ent->name[key->len];
445 * Return the index of the entry with the given refname from the
446 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
447 * no such entry is found. dir must already be complete.
449 static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
451 struct ref_entry **r;
452 struct string_slice key;
454 if (refname == NULL || !dir->nr)
455 return -1;
457 sort_ref_dir(dir);
458 key.len = len;
459 key.str = refname;
460 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
461 ref_entry_cmp_sslice);
463 if (r == NULL)
464 return -1;
466 return r - dir->entries;
470 * Search for a directory entry directly within dir (without
471 * recursing). Sort dir if necessary. subdirname must be a directory
472 * name (i.e., end in '/'). If mkdir is set, then create the
473 * directory if it is missing; otherwise, return NULL if the desired
474 * directory cannot be found. dir must already be complete.
476 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
477 const char *subdirname, size_t len,
478 int mkdir)
480 int entry_index = search_ref_dir(dir, subdirname, len);
481 struct ref_entry *entry;
482 if (entry_index == -1) {
483 if (!mkdir)
484 return NULL;
486 * Since dir is complete, the absence of a subdir
487 * means that the subdir really doesn't exist;
488 * therefore, create an empty record for it but mark
489 * the record complete.
491 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
492 add_entry_to_dir(dir, entry);
493 } else {
494 entry = dir->entries[entry_index];
496 return get_ref_dir(entry);
500 * If refname is a reference name, find the ref_dir within the dir
501 * tree that should hold refname. If refname is a directory name
502 * (i.e., ends in '/'), then return that ref_dir itself. dir must
503 * represent the top-level directory and must already be complete.
504 * Sort ref_dirs and recurse into subdirectories as necessary. If
505 * mkdir is set, then create any missing directories; otherwise,
506 * return NULL if the desired directory cannot be found.
508 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
509 const char *refname, int mkdir)
511 const char *slash;
512 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
513 size_t dirnamelen = slash - refname + 1;
514 struct ref_dir *subdir;
515 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
516 if (!subdir) {
517 dir = NULL;
518 break;
520 dir = subdir;
523 return dir;
527 * Find the value entry with the given name in dir, sorting ref_dirs
528 * and recursing into subdirectories as necessary. If the name is not
529 * found or it corresponds to a directory entry, return NULL.
531 static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
533 int entry_index;
534 struct ref_entry *entry;
535 dir = find_containing_dir(dir, refname, 0);
536 if (!dir)
537 return NULL;
538 entry_index = search_ref_dir(dir, refname, strlen(refname));
539 if (entry_index == -1)
540 return NULL;
541 entry = dir->entries[entry_index];
542 return (entry->flag & REF_DIR) ? NULL : entry;
546 * Remove the entry with the given name from dir, recursing into
547 * subdirectories as necessary. If refname is the name of a directory
548 * (i.e., ends with '/'), then remove the directory and its contents.
549 * If the removal was successful, return the number of entries
550 * remaining in the directory entry that contained the deleted entry.
551 * If the name was not found, return -1. Please note that this
552 * function only deletes the entry from the cache; it does not delete
553 * it from the filesystem or ensure that other cache entries (which
554 * might be symbolic references to the removed entry) are updated.
555 * Nor does it remove any containing dir entries that might be made
556 * empty by the removal. dir must represent the top-level directory
557 * and must already be complete.
559 static int remove_entry(struct ref_dir *dir, const char *refname)
561 int refname_len = strlen(refname);
562 int entry_index;
563 struct ref_entry *entry;
564 int is_dir = refname[refname_len - 1] == '/';
565 if (is_dir) {
567 * refname represents a reference directory. Remove
568 * the trailing slash; otherwise we will get the
569 * directory *representing* refname rather than the
570 * one *containing* it.
572 char *dirname = xmemdupz(refname, refname_len - 1);
573 dir = find_containing_dir(dir, dirname, 0);
574 free(dirname);
575 } else {
576 dir = find_containing_dir(dir, refname, 0);
578 if (!dir)
579 return -1;
580 entry_index = search_ref_dir(dir, refname, refname_len);
581 if (entry_index == -1)
582 return -1;
583 entry = dir->entries[entry_index];
585 memmove(&dir->entries[entry_index],
586 &dir->entries[entry_index + 1],
587 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
589 dir->nr--;
590 if (dir->sorted > entry_index)
591 dir->sorted--;
592 free_ref_entry(entry);
593 return dir->nr;
597 * Add a ref_entry to the ref_dir (unsorted), recursing into
598 * subdirectories as necessary. dir must represent the top-level
599 * directory. Return 0 on success.
601 static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
603 dir = find_containing_dir(dir, ref->name, 1);
604 if (!dir)
605 return -1;
606 add_entry_to_dir(dir, ref);
607 return 0;
611 * Emit a warning and return true iff ref1 and ref2 have the same name
612 * and the same sha1. Die if they have the same name but different
613 * sha1s.
615 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
617 if (strcmp(ref1->name, ref2->name))
618 return 0;
620 /* Duplicate name; make sure that they don't conflict: */
622 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
623 /* This is impossible by construction */
624 die("Reference directory conflict: %s", ref1->name);
626 if (hashcmp(ref1->u.value.sha1, ref2->u.value.sha1))
627 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
629 warning("Duplicated ref: %s", ref1->name);
630 return 1;
634 * Sort the entries in dir non-recursively (if they are not already
635 * sorted) and remove any duplicate entries.
637 static void sort_ref_dir(struct ref_dir *dir)
639 int i, j;
640 struct ref_entry *last = NULL;
643 * This check also prevents passing a zero-length array to qsort(),
644 * which is a problem on some platforms.
646 if (dir->sorted == dir->nr)
647 return;
649 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
651 /* Remove any duplicates: */
652 for (i = 0, j = 0; j < dir->nr; j++) {
653 struct ref_entry *entry = dir->entries[j];
654 if (last && is_dup_ref(last, entry))
655 free_ref_entry(entry);
656 else
657 last = dir->entries[i++] = entry;
659 dir->sorted = dir->nr = i;
662 /* Include broken references in a do_for_each_ref*() iteration: */
663 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
666 * Return true iff the reference described by entry can be resolved to
667 * an object in the database. Emit a warning if the referred-to
668 * object does not exist.
670 static int ref_resolves_to_object(struct ref_entry *entry)
672 if (entry->flag & REF_ISBROKEN)
673 return 0;
674 if (!has_sha1_file(entry->u.value.sha1)) {
675 error("%s does not point to a valid object!", entry->name);
676 return 0;
678 return 1;
682 * current_ref is a performance hack: when iterating over references
683 * using the for_each_ref*() functions, current_ref is set to the
684 * current reference's entry before calling the callback function. If
685 * the callback function calls peel_ref(), then peel_ref() first
686 * checks whether the reference to be peeled is the current reference
687 * (it usually is) and if so, returns that reference's peeled version
688 * if it is available. This avoids a refname lookup in a common case.
690 static struct ref_entry *current_ref;
692 typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
694 struct ref_entry_cb {
695 const char *base;
696 int trim;
697 int flags;
698 each_ref_fn *fn;
699 void *cb_data;
703 * Handle one reference in a do_for_each_ref*()-style iteration,
704 * calling an each_ref_fn for each entry.
706 static int do_one_ref(struct ref_entry *entry, void *cb_data)
708 struct ref_entry_cb *data = cb_data;
709 struct ref_entry *old_current_ref;
710 int retval;
712 if (!starts_with(entry->name, data->base))
713 return 0;
715 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
716 !ref_resolves_to_object(entry))
717 return 0;
719 /* Store the old value, in case this is a recursive call: */
720 old_current_ref = current_ref;
721 current_ref = entry;
722 retval = data->fn(entry->name + data->trim, entry->u.value.sha1,
723 entry->flag, data->cb_data);
724 current_ref = old_current_ref;
725 return retval;
729 * Call fn for each reference in dir that has index in the range
730 * offset <= index < dir->nr. Recurse into subdirectories that are in
731 * that index range, sorting them before iterating. This function
732 * does not sort dir itself; it should be sorted beforehand. fn is
733 * called for all references, including broken ones.
735 static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
736 each_ref_entry_fn fn, void *cb_data)
738 int i;
739 assert(dir->sorted == dir->nr);
740 for (i = offset; i < dir->nr; i++) {
741 struct ref_entry *entry = dir->entries[i];
742 int retval;
743 if (entry->flag & REF_DIR) {
744 struct ref_dir *subdir = get_ref_dir(entry);
745 sort_ref_dir(subdir);
746 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
747 } else {
748 retval = fn(entry, cb_data);
750 if (retval)
751 return retval;
753 return 0;
757 * Call fn for each reference in the union of dir1 and dir2, in order
758 * by refname. Recurse into subdirectories. If a value entry appears
759 * in both dir1 and dir2, then only process the version that is in
760 * dir2. The input dirs must already be sorted, but subdirs will be
761 * sorted as needed. fn is called for all references, including
762 * broken ones.
764 static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
765 struct ref_dir *dir2,
766 each_ref_entry_fn fn, void *cb_data)
768 int retval;
769 int i1 = 0, i2 = 0;
771 assert(dir1->sorted == dir1->nr);
772 assert(dir2->sorted == dir2->nr);
773 while (1) {
774 struct ref_entry *e1, *e2;
775 int cmp;
776 if (i1 == dir1->nr) {
777 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
779 if (i2 == dir2->nr) {
780 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
782 e1 = dir1->entries[i1];
783 e2 = dir2->entries[i2];
784 cmp = strcmp(e1->name, e2->name);
785 if (cmp == 0) {
786 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
787 /* Both are directories; descend them in parallel. */
788 struct ref_dir *subdir1 = get_ref_dir(e1);
789 struct ref_dir *subdir2 = get_ref_dir(e2);
790 sort_ref_dir(subdir1);
791 sort_ref_dir(subdir2);
792 retval = do_for_each_entry_in_dirs(
793 subdir1, subdir2, fn, cb_data);
794 i1++;
795 i2++;
796 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
797 /* Both are references; ignore the one from dir1. */
798 retval = fn(e2, cb_data);
799 i1++;
800 i2++;
801 } else {
802 die("conflict between reference and directory: %s",
803 e1->name);
805 } else {
806 struct ref_entry *e;
807 if (cmp < 0) {
808 e = e1;
809 i1++;
810 } else {
811 e = e2;
812 i2++;
814 if (e->flag & REF_DIR) {
815 struct ref_dir *subdir = get_ref_dir(e);
816 sort_ref_dir(subdir);
817 retval = do_for_each_entry_in_dir(
818 subdir, 0, fn, cb_data);
819 } else {
820 retval = fn(e, cb_data);
823 if (retval)
824 return retval;
829 * Load all of the refs from the dir into our in-memory cache. The hard work
830 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
831 * through all of the sub-directories. We do not even need to care about
832 * sorting, as traversal order does not matter to us.
834 static void prime_ref_dir(struct ref_dir *dir)
836 int i;
837 for (i = 0; i < dir->nr; i++) {
838 struct ref_entry *entry = dir->entries[i];
839 if (entry->flag & REF_DIR)
840 prime_ref_dir(get_ref_dir(entry));
844 static int entry_matches(struct ref_entry *entry, const struct string_list *list)
846 return list && string_list_has_string(list, entry->name);
849 struct nonmatching_ref_data {
850 const struct string_list *skip;
851 struct ref_entry *found;
854 static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
856 struct nonmatching_ref_data *data = vdata;
858 if (entry_matches(entry, data->skip))
859 return 0;
861 data->found = entry;
862 return 1;
865 static void report_refname_conflict(struct ref_entry *entry,
866 const char *refname)
868 error("'%s' exists; cannot create '%s'", entry->name, refname);
872 * Return true iff a reference named refname could be created without
873 * conflicting with the name of an existing reference in dir. If
874 * skip is non-NULL, ignore potential conflicts with refs in skip
875 * (e.g., because they are scheduled for deletion in the same
876 * operation).
878 * Two reference names conflict if one of them exactly matches the
879 * leading components of the other; e.g., "foo/bar" conflicts with
880 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
881 * "foo/barbados".
883 * skip must be sorted.
885 static int is_refname_available(const char *refname,
886 const struct string_list *skip,
887 struct ref_dir *dir)
889 const char *slash;
890 size_t len;
891 int pos;
892 char *dirname;
894 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
896 * We are still at a leading dir of the refname; we are
897 * looking for a conflict with a leaf entry.
899 * If we find one, we still must make sure it is
900 * not in "skip".
902 pos = search_ref_dir(dir, refname, slash - refname);
903 if (pos >= 0) {
904 struct ref_entry *entry = dir->entries[pos];
905 if (entry_matches(entry, skip))
906 return 1;
907 report_refname_conflict(entry, refname);
908 return 0;
913 * Otherwise, we can try to continue our search with
914 * the next component; if we come up empty, we know
915 * there is nothing under this whole prefix.
917 pos = search_ref_dir(dir, refname, slash + 1 - refname);
918 if (pos < 0)
919 return 1;
921 dir = get_ref_dir(dir->entries[pos]);
925 * We are at the leaf of our refname; we want to
926 * make sure there are no directories which match it.
928 len = strlen(refname);
929 dirname = xmallocz(len + 1);
930 sprintf(dirname, "%s/", refname);
931 pos = search_ref_dir(dir, dirname, len + 1);
932 free(dirname);
934 if (pos >= 0) {
936 * We found a directory named "refname". It is a
937 * problem iff it contains any ref that is not
938 * in "skip".
940 struct ref_entry *entry = dir->entries[pos];
941 struct ref_dir *dir = get_ref_dir(entry);
942 struct nonmatching_ref_data data;
944 data.skip = skip;
945 sort_ref_dir(dir);
946 if (!do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data))
947 return 1;
949 report_refname_conflict(data.found, refname);
950 return 0;
954 * There is no point in searching for another leaf
955 * node which matches it; such an entry would be the
956 * ref we are looking for, not a conflict.
958 return 1;
961 struct packed_ref_cache {
962 struct ref_entry *root;
965 * Count of references to the data structure in this instance,
966 * including the pointer from ref_cache::packed if any. The
967 * data will not be freed as long as the reference count is
968 * nonzero.
970 unsigned int referrers;
973 * Iff the packed-refs file associated with this instance is
974 * currently locked for writing, this points at the associated
975 * lock (which is owned by somebody else). The referrer count
976 * is also incremented when the file is locked and decremented
977 * when it is unlocked.
979 struct lock_file *lock;
981 /* The metadata from when this packed-refs cache was read */
982 struct stat_validity validity;
986 * Future: need to be in "struct repository"
987 * when doing a full libification.
989 static struct ref_cache {
990 struct ref_cache *next;
991 struct ref_entry *loose;
992 struct packed_ref_cache *packed;
994 * The submodule name, or "" for the main repo. We allocate
995 * length 1 rather than FLEX_ARRAY so that the main ref_cache
996 * is initialized correctly.
998 char name[1];
999 } ref_cache, *submodule_ref_caches;
1001 /* Lock used for the main packed-refs file: */
1002 static struct lock_file packlock;
1005 * Increment the reference count of *packed_refs.
1007 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
1009 packed_refs->referrers++;
1013 * Decrease the reference count of *packed_refs. If it goes to zero,
1014 * free *packed_refs and return true; otherwise return false.
1016 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
1018 if (!--packed_refs->referrers) {
1019 free_ref_entry(packed_refs->root);
1020 stat_validity_clear(&packed_refs->validity);
1021 free(packed_refs);
1022 return 1;
1023 } else {
1024 return 0;
1028 static void clear_packed_ref_cache(struct ref_cache *refs)
1030 if (refs->packed) {
1031 struct packed_ref_cache *packed_refs = refs->packed;
1033 if (packed_refs->lock)
1034 die("internal error: packed-ref cache cleared while locked");
1035 refs->packed = NULL;
1036 release_packed_ref_cache(packed_refs);
1040 static void clear_loose_ref_cache(struct ref_cache *refs)
1042 if (refs->loose) {
1043 free_ref_entry(refs->loose);
1044 refs->loose = NULL;
1048 static struct ref_cache *create_ref_cache(const char *submodule)
1050 int len;
1051 struct ref_cache *refs;
1052 if (!submodule)
1053 submodule = "";
1054 len = strlen(submodule) + 1;
1055 refs = xcalloc(1, sizeof(struct ref_cache) + len);
1056 memcpy(refs->name, submodule, len);
1057 return refs;
1061 * Return a pointer to a ref_cache for the specified submodule. For
1062 * the main repository, use submodule==NULL. The returned structure
1063 * will be allocated and initialized but not necessarily populated; it
1064 * should not be freed.
1066 static struct ref_cache *get_ref_cache(const char *submodule)
1068 struct ref_cache *refs;
1070 if (!submodule || !*submodule)
1071 return &ref_cache;
1073 for (refs = submodule_ref_caches; refs; refs = refs->next)
1074 if (!strcmp(submodule, refs->name))
1075 return refs;
1077 refs = create_ref_cache(submodule);
1078 refs->next = submodule_ref_caches;
1079 submodule_ref_caches = refs;
1080 return refs;
1083 /* The length of a peeled reference line in packed-refs, including EOL: */
1084 #define PEELED_LINE_LENGTH 42
1087 * The packed-refs header line that we write out. Perhaps other
1088 * traits will be added later. The trailing space is required.
1090 static const char PACKED_REFS_HEADER[] =
1091 "# pack-refs with: peeled fully-peeled \n";
1094 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1095 * Return a pointer to the refname within the line (null-terminated),
1096 * or NULL if there was a problem.
1098 static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1100 const char *ref;
1103 * 42: the answer to everything.
1105 * In this case, it happens to be the answer to
1106 * 40 (length of sha1 hex representation)
1107 * +1 (space in between hex and name)
1108 * +1 (newline at the end of the line)
1110 if (line->len <= 42)
1111 return NULL;
1113 if (get_sha1_hex(line->buf, sha1) < 0)
1114 return NULL;
1115 if (!isspace(line->buf[40]))
1116 return NULL;
1118 ref = line->buf + 41;
1119 if (isspace(*ref))
1120 return NULL;
1122 if (line->buf[line->len - 1] != '\n')
1123 return NULL;
1124 line->buf[--line->len] = 0;
1126 return ref;
1130 * Read f, which is a packed-refs file, into dir.
1132 * A comment line of the form "# pack-refs with: " may contain zero or
1133 * more traits. We interpret the traits as follows:
1135 * No traits:
1137 * Probably no references are peeled. But if the file contains a
1138 * peeled value for a reference, we will use it.
1140 * peeled:
1142 * References under "refs/tags/", if they *can* be peeled, *are*
1143 * peeled in this file. References outside of "refs/tags/" are
1144 * probably not peeled even if they could have been, but if we find
1145 * a peeled value for such a reference we will use it.
1147 * fully-peeled:
1149 * All references in the file that can be peeled are peeled.
1150 * Inversely (and this is more important), any references in the
1151 * file for which no peeled value is recorded is not peelable. This
1152 * trait should typically be written alongside "peeled" for
1153 * compatibility with older clients, but we do not require it
1154 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1156 static void read_packed_refs(FILE *f, struct ref_dir *dir)
1158 struct ref_entry *last = NULL;
1159 struct strbuf line = STRBUF_INIT;
1160 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1162 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1163 unsigned char sha1[20];
1164 const char *refname;
1165 const char *traits;
1167 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1168 if (strstr(traits, " fully-peeled "))
1169 peeled = PEELED_FULLY;
1170 else if (strstr(traits, " peeled "))
1171 peeled = PEELED_TAGS;
1172 /* perhaps other traits later as well */
1173 continue;
1176 refname = parse_ref_line(&line, sha1);
1177 if (refname) {
1178 int flag = REF_ISPACKED;
1180 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1181 hashclr(sha1);
1182 flag |= REF_BAD_NAME | REF_ISBROKEN;
1184 last = create_ref_entry(refname, sha1, flag, 0);
1185 if (peeled == PEELED_FULLY ||
1186 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1187 last->flag |= REF_KNOWS_PEELED;
1188 add_ref(dir, last);
1189 continue;
1191 if (last &&
1192 line.buf[0] == '^' &&
1193 line.len == PEELED_LINE_LENGTH &&
1194 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1195 !get_sha1_hex(line.buf + 1, sha1)) {
1196 hashcpy(last->u.value.peeled, sha1);
1198 * Regardless of what the file header said,
1199 * we definitely know the value of *this*
1200 * reference:
1202 last->flag |= REF_KNOWS_PEELED;
1206 strbuf_release(&line);
1210 * Get the packed_ref_cache for the specified ref_cache, creating it
1211 * if necessary.
1213 static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1215 const char *packed_refs_file;
1217 if (*refs->name)
1218 packed_refs_file = git_path_submodule(refs->name, "packed-refs");
1219 else
1220 packed_refs_file = git_path("packed-refs");
1222 if (refs->packed &&
1223 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1224 clear_packed_ref_cache(refs);
1226 if (!refs->packed) {
1227 FILE *f;
1229 refs->packed = xcalloc(1, sizeof(*refs->packed));
1230 acquire_packed_ref_cache(refs->packed);
1231 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1232 f = fopen(packed_refs_file, "r");
1233 if (f) {
1234 stat_validity_update(&refs->packed->validity, fileno(f));
1235 read_packed_refs(f, get_ref_dir(refs->packed->root));
1236 fclose(f);
1239 return refs->packed;
1242 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1244 return get_ref_dir(packed_ref_cache->root);
1247 static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1249 return get_packed_ref_dir(get_packed_ref_cache(refs));
1252 void add_packed_ref(const char *refname, const unsigned char *sha1)
1254 struct packed_ref_cache *packed_ref_cache =
1255 get_packed_ref_cache(&ref_cache);
1257 if (!packed_ref_cache->lock)
1258 die("internal error: packed refs not locked");
1259 add_ref(get_packed_ref_dir(packed_ref_cache),
1260 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1264 * Read the loose references from the namespace dirname into dir
1265 * (without recursing). dirname must end with '/'. dir must be the
1266 * directory entry corresponding to dirname.
1268 static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1270 struct ref_cache *refs = dir->ref_cache;
1271 DIR *d;
1272 const char *path;
1273 struct dirent *de;
1274 int dirnamelen = strlen(dirname);
1275 struct strbuf refname;
1277 if (*refs->name)
1278 path = git_path_submodule(refs->name, "%s", dirname);
1279 else
1280 path = git_path("%s", dirname);
1282 d = opendir(path);
1283 if (!d)
1284 return;
1286 strbuf_init(&refname, dirnamelen + 257);
1287 strbuf_add(&refname, dirname, dirnamelen);
1289 while ((de = readdir(d)) != NULL) {
1290 unsigned char sha1[20];
1291 struct stat st;
1292 int flag;
1293 const char *refdir;
1295 if (de->d_name[0] == '.')
1296 continue;
1297 if (ends_with(de->d_name, ".lock"))
1298 continue;
1299 strbuf_addstr(&refname, de->d_name);
1300 refdir = *refs->name
1301 ? git_path_submodule(refs->name, "%s", refname.buf)
1302 : git_path("%s", refname.buf);
1303 if (stat(refdir, &st) < 0) {
1304 ; /* silently ignore */
1305 } else if (S_ISDIR(st.st_mode)) {
1306 strbuf_addch(&refname, '/');
1307 add_entry_to_dir(dir,
1308 create_dir_entry(refs, refname.buf,
1309 refname.len, 1));
1310 } else {
1311 if (*refs->name) {
1312 hashclr(sha1);
1313 flag = 0;
1314 if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) {
1315 hashclr(sha1);
1316 flag |= REF_ISBROKEN;
1318 } else if (read_ref_full(refname.buf,
1319 RESOLVE_REF_READING,
1320 sha1, &flag)) {
1321 hashclr(sha1);
1322 flag |= REF_ISBROKEN;
1324 if (check_refname_format(refname.buf,
1325 REFNAME_ALLOW_ONELEVEL)) {
1326 hashclr(sha1);
1327 flag |= REF_BAD_NAME | REF_ISBROKEN;
1329 add_entry_to_dir(dir,
1330 create_ref_entry(refname.buf, sha1, flag, 0));
1332 strbuf_setlen(&refname, dirnamelen);
1334 strbuf_release(&refname);
1335 closedir(d);
1338 static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1340 if (!refs->loose) {
1342 * Mark the top-level directory complete because we
1343 * are about to read the only subdirectory that can
1344 * hold references:
1346 refs->loose = create_dir_entry(refs, "", 0, 0);
1348 * Create an incomplete entry for "refs/":
1350 add_entry_to_dir(get_ref_dir(refs->loose),
1351 create_dir_entry(refs, "refs/", 5, 1));
1353 return get_ref_dir(refs->loose);
1356 /* We allow "recursive" symbolic refs. Only within reason, though */
1357 #define MAXDEPTH 5
1358 #define MAXREFLEN (1024)
1361 * Called by resolve_gitlink_ref_recursive() after it failed to read
1362 * from the loose refs in ref_cache refs. Find <refname> in the
1363 * packed-refs file for the submodule.
1365 static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1366 const char *refname, unsigned char *sha1)
1368 struct ref_entry *ref;
1369 struct ref_dir *dir = get_packed_refs(refs);
1371 ref = find_ref(dir, refname);
1372 if (ref == NULL)
1373 return -1;
1375 hashcpy(sha1, ref->u.value.sha1);
1376 return 0;
1379 static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1380 const char *refname, unsigned char *sha1,
1381 int recursion)
1383 int fd, len;
1384 char buffer[128], *p;
1385 char *path;
1387 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1388 return -1;
1389 path = *refs->name
1390 ? git_path_submodule(refs->name, "%s", refname)
1391 : git_path("%s", refname);
1392 fd = open(path, O_RDONLY);
1393 if (fd < 0)
1394 return resolve_gitlink_packed_ref(refs, refname, sha1);
1396 len = read(fd, buffer, sizeof(buffer)-1);
1397 close(fd);
1398 if (len < 0)
1399 return -1;
1400 while (len && isspace(buffer[len-1]))
1401 len--;
1402 buffer[len] = 0;
1404 /* Was it a detached head or an old-fashioned symlink? */
1405 if (!get_sha1_hex(buffer, sha1))
1406 return 0;
1408 /* Symref? */
1409 if (strncmp(buffer, "ref:", 4))
1410 return -1;
1411 p = buffer + 4;
1412 while (isspace(*p))
1413 p++;
1415 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1418 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1420 int len = strlen(path), retval;
1421 char *submodule;
1422 struct ref_cache *refs;
1424 while (len && path[len-1] == '/')
1425 len--;
1426 if (!len)
1427 return -1;
1428 submodule = xstrndup(path, len);
1429 refs = get_ref_cache(submodule);
1430 free(submodule);
1432 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1433 return retval;
1437 * Return the ref_entry for the given refname from the packed
1438 * references. If it does not exist, return NULL.
1440 static struct ref_entry *get_packed_ref(const char *refname)
1442 return find_ref(get_packed_refs(&ref_cache), refname);
1446 * A loose ref file doesn't exist; check for a packed ref. The
1447 * options are forwarded from resolve_safe_unsafe().
1449 static int resolve_missing_loose_ref(const char *refname,
1450 int resolve_flags,
1451 unsigned char *sha1,
1452 int *flags)
1454 struct ref_entry *entry;
1457 * The loose reference file does not exist; check for a packed
1458 * reference.
1460 entry = get_packed_ref(refname);
1461 if (entry) {
1462 hashcpy(sha1, entry->u.value.sha1);
1463 if (flags)
1464 *flags |= REF_ISPACKED;
1465 return 0;
1467 /* The reference is not a packed reference, either. */
1468 if (resolve_flags & RESOLVE_REF_READING) {
1469 errno = ENOENT;
1470 return -1;
1471 } else {
1472 hashclr(sha1);
1473 return 0;
1477 /* This function needs to return a meaningful errno on failure */
1478 const char *resolve_ref_unsafe(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1480 int depth = MAXDEPTH;
1481 ssize_t len;
1482 char buffer[256];
1483 static char refname_buffer[256];
1484 int bad_name = 0;
1486 if (flags)
1487 *flags = 0;
1489 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1490 if (flags)
1491 *flags |= REF_BAD_NAME;
1493 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1494 !refname_is_safe(refname)) {
1495 errno = EINVAL;
1496 return NULL;
1499 * dwim_ref() uses REF_ISBROKEN to distinguish between
1500 * missing refs and refs that were present but invalid,
1501 * to complain about the latter to stderr.
1503 * We don't know whether the ref exists, so don't set
1504 * REF_ISBROKEN yet.
1506 bad_name = 1;
1508 for (;;) {
1509 char path[PATH_MAX];
1510 struct stat st;
1511 char *buf;
1512 int fd;
1514 if (--depth < 0) {
1515 errno = ELOOP;
1516 return NULL;
1519 git_snpath(path, sizeof(path), "%s", refname);
1522 * We might have to loop back here to avoid a race
1523 * condition: first we lstat() the file, then we try
1524 * to read it as a link or as a file. But if somebody
1525 * changes the type of the file (file <-> directory
1526 * <-> symlink) between the lstat() and reading, then
1527 * we don't want to report that as an error but rather
1528 * try again starting with the lstat().
1530 stat_ref:
1531 if (lstat(path, &st) < 0) {
1532 if (errno != ENOENT)
1533 return NULL;
1534 if (resolve_missing_loose_ref(refname, resolve_flags,
1535 sha1, flags))
1536 return NULL;
1537 if (bad_name) {
1538 hashclr(sha1);
1539 if (flags)
1540 *flags |= REF_ISBROKEN;
1542 return refname;
1545 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1546 if (S_ISLNK(st.st_mode)) {
1547 len = readlink(path, buffer, sizeof(buffer)-1);
1548 if (len < 0) {
1549 if (errno == ENOENT || errno == EINVAL)
1550 /* inconsistent with lstat; retry */
1551 goto stat_ref;
1552 else
1553 return NULL;
1555 buffer[len] = 0;
1556 if (starts_with(buffer, "refs/") &&
1557 !check_refname_format(buffer, 0)) {
1558 strcpy(refname_buffer, buffer);
1559 refname = refname_buffer;
1560 if (flags)
1561 *flags |= REF_ISSYMREF;
1562 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1563 hashclr(sha1);
1564 return refname;
1566 continue;
1570 /* Is it a directory? */
1571 if (S_ISDIR(st.st_mode)) {
1572 errno = EISDIR;
1573 return NULL;
1577 * Anything else, just open it and try to use it as
1578 * a ref
1580 fd = open(path, O_RDONLY);
1581 if (fd < 0) {
1582 if (errno == ENOENT)
1583 /* inconsistent with lstat; retry */
1584 goto stat_ref;
1585 else
1586 return NULL;
1588 len = read_in_full(fd, buffer, sizeof(buffer)-1);
1589 if (len < 0) {
1590 int save_errno = errno;
1591 close(fd);
1592 errno = save_errno;
1593 return NULL;
1595 close(fd);
1596 while (len && isspace(buffer[len-1]))
1597 len--;
1598 buffer[len] = '\0';
1601 * Is it a symbolic ref?
1603 if (!starts_with(buffer, "ref:")) {
1605 * Please note that FETCH_HEAD has a second
1606 * line containing other data.
1608 if (get_sha1_hex(buffer, sha1) ||
1609 (buffer[40] != '\0' && !isspace(buffer[40]))) {
1610 if (flags)
1611 *flags |= REF_ISBROKEN;
1612 errno = EINVAL;
1613 return NULL;
1615 if (bad_name) {
1616 hashclr(sha1);
1617 if (flags)
1618 *flags |= REF_ISBROKEN;
1620 return refname;
1622 if (flags)
1623 *flags |= REF_ISSYMREF;
1624 buf = buffer + 4;
1625 while (isspace(*buf))
1626 buf++;
1627 refname = strcpy(refname_buffer, buf);
1628 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1629 hashclr(sha1);
1630 return refname;
1632 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1633 if (flags)
1634 *flags |= REF_ISBROKEN;
1636 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1637 !refname_is_safe(buf)) {
1638 errno = EINVAL;
1639 return NULL;
1641 bad_name = 1;
1646 char *resolve_refdup(const char *ref, int resolve_flags, unsigned char *sha1, int *flags)
1648 return xstrdup_or_null(resolve_ref_unsafe(ref, resolve_flags, sha1, flags));
1651 /* The argument to filter_refs */
1652 struct ref_filter {
1653 const char *pattern;
1654 each_ref_fn *fn;
1655 void *cb_data;
1658 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1660 if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
1661 return 0;
1662 return -1;
1665 int read_ref(const char *refname, unsigned char *sha1)
1667 return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
1670 int ref_exists(const char *refname)
1672 unsigned char sha1[20];
1673 return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
1676 static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
1677 void *data)
1679 struct ref_filter *filter = (struct ref_filter *)data;
1680 if (wildmatch(filter->pattern, refname, 0, NULL))
1681 return 0;
1682 return filter->fn(refname, sha1, flags, filter->cb_data);
1685 enum peel_status {
1686 /* object was peeled successfully: */
1687 PEEL_PEELED = 0,
1690 * object cannot be peeled because the named object (or an
1691 * object referred to by a tag in the peel chain), does not
1692 * exist.
1694 PEEL_INVALID = -1,
1696 /* object cannot be peeled because it is not a tag: */
1697 PEEL_NON_TAG = -2,
1699 /* ref_entry contains no peeled value because it is a symref: */
1700 PEEL_IS_SYMREF = -3,
1703 * ref_entry cannot be peeled because it is broken (i.e., the
1704 * symbolic reference cannot even be resolved to an object
1705 * name):
1707 PEEL_BROKEN = -4
1711 * Peel the named object; i.e., if the object is a tag, resolve the
1712 * tag recursively until a non-tag is found. If successful, store the
1713 * result to sha1 and return PEEL_PEELED. If the object is not a tag
1714 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
1715 * and leave sha1 unchanged.
1717 static enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
1719 struct object *o = lookup_unknown_object(name);
1721 if (o->type == OBJ_NONE) {
1722 int type = sha1_object_info(name, NULL);
1723 if (type < 0 || !object_as_type(o, type, 0))
1724 return PEEL_INVALID;
1727 if (o->type != OBJ_TAG)
1728 return PEEL_NON_TAG;
1730 o = deref_tag_noverify(o);
1731 if (!o)
1732 return PEEL_INVALID;
1734 hashcpy(sha1, o->sha1);
1735 return PEEL_PEELED;
1739 * Peel the entry (if possible) and return its new peel_status. If
1740 * repeel is true, re-peel the entry even if there is an old peeled
1741 * value that is already stored in it.
1743 * It is OK to call this function with a packed reference entry that
1744 * might be stale and might even refer to an object that has since
1745 * been garbage-collected. In such a case, if the entry has
1746 * REF_KNOWS_PEELED then leave the status unchanged and return
1747 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1749 static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1751 enum peel_status status;
1753 if (entry->flag & REF_KNOWS_PEELED) {
1754 if (repeel) {
1755 entry->flag &= ~REF_KNOWS_PEELED;
1756 hashclr(entry->u.value.peeled);
1757 } else {
1758 return is_null_sha1(entry->u.value.peeled) ?
1759 PEEL_NON_TAG : PEEL_PEELED;
1762 if (entry->flag & REF_ISBROKEN)
1763 return PEEL_BROKEN;
1764 if (entry->flag & REF_ISSYMREF)
1765 return PEEL_IS_SYMREF;
1767 status = peel_object(entry->u.value.sha1, entry->u.value.peeled);
1768 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1769 entry->flag |= REF_KNOWS_PEELED;
1770 return status;
1773 int peel_ref(const char *refname, unsigned char *sha1)
1775 int flag;
1776 unsigned char base[20];
1778 if (current_ref && (current_ref->name == refname
1779 || !strcmp(current_ref->name, refname))) {
1780 if (peel_entry(current_ref, 0))
1781 return -1;
1782 hashcpy(sha1, current_ref->u.value.peeled);
1783 return 0;
1786 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1787 return -1;
1790 * If the reference is packed, read its ref_entry from the
1791 * cache in the hope that we already know its peeled value.
1792 * We only try this optimization on packed references because
1793 * (a) forcing the filling of the loose reference cache could
1794 * be expensive and (b) loose references anyway usually do not
1795 * have REF_KNOWS_PEELED.
1797 if (flag & REF_ISPACKED) {
1798 struct ref_entry *r = get_packed_ref(refname);
1799 if (r) {
1800 if (peel_entry(r, 0))
1801 return -1;
1802 hashcpy(sha1, r->u.value.peeled);
1803 return 0;
1807 return peel_object(base, sha1);
1810 struct warn_if_dangling_data {
1811 FILE *fp;
1812 const char *refname;
1813 const struct string_list *refnames;
1814 const char *msg_fmt;
1817 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
1818 int flags, void *cb_data)
1820 struct warn_if_dangling_data *d = cb_data;
1821 const char *resolves_to;
1822 unsigned char junk[20];
1824 if (!(flags & REF_ISSYMREF))
1825 return 0;
1827 resolves_to = resolve_ref_unsafe(refname, 0, junk, NULL);
1828 if (!resolves_to
1829 || (d->refname
1830 ? strcmp(resolves_to, d->refname)
1831 : !string_list_has_string(d->refnames, resolves_to))) {
1832 return 0;
1835 fprintf(d->fp, d->msg_fmt, refname);
1836 fputc('\n', d->fp);
1837 return 0;
1840 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1842 struct warn_if_dangling_data data;
1844 data.fp = fp;
1845 data.refname = refname;
1846 data.refnames = NULL;
1847 data.msg_fmt = msg_fmt;
1848 for_each_rawref(warn_if_dangling_symref, &data);
1851 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
1853 struct warn_if_dangling_data data;
1855 data.fp = fp;
1856 data.refname = NULL;
1857 data.refnames = refnames;
1858 data.msg_fmt = msg_fmt;
1859 for_each_rawref(warn_if_dangling_symref, &data);
1863 * Call fn for each reference in the specified ref_cache, omitting
1864 * references not in the containing_dir of base. fn is called for all
1865 * references, including broken ones. If fn ever returns a non-zero
1866 * value, stop the iteration and return that value; otherwise, return
1867 * 0.
1869 static int do_for_each_entry(struct ref_cache *refs, const char *base,
1870 each_ref_entry_fn fn, void *cb_data)
1872 struct packed_ref_cache *packed_ref_cache;
1873 struct ref_dir *loose_dir;
1874 struct ref_dir *packed_dir;
1875 int retval = 0;
1878 * We must make sure that all loose refs are read before accessing the
1879 * packed-refs file; this avoids a race condition in which loose refs
1880 * are migrated to the packed-refs file by a simultaneous process, but
1881 * our in-memory view is from before the migration. get_packed_ref_cache()
1882 * takes care of making sure our view is up to date with what is on
1883 * disk.
1885 loose_dir = get_loose_refs(refs);
1886 if (base && *base) {
1887 loose_dir = find_containing_dir(loose_dir, base, 0);
1889 if (loose_dir)
1890 prime_ref_dir(loose_dir);
1892 packed_ref_cache = get_packed_ref_cache(refs);
1893 acquire_packed_ref_cache(packed_ref_cache);
1894 packed_dir = get_packed_ref_dir(packed_ref_cache);
1895 if (base && *base) {
1896 packed_dir = find_containing_dir(packed_dir, base, 0);
1899 if (packed_dir && loose_dir) {
1900 sort_ref_dir(packed_dir);
1901 sort_ref_dir(loose_dir);
1902 retval = do_for_each_entry_in_dirs(
1903 packed_dir, loose_dir, fn, cb_data);
1904 } else if (packed_dir) {
1905 sort_ref_dir(packed_dir);
1906 retval = do_for_each_entry_in_dir(
1907 packed_dir, 0, fn, cb_data);
1908 } else if (loose_dir) {
1909 sort_ref_dir(loose_dir);
1910 retval = do_for_each_entry_in_dir(
1911 loose_dir, 0, fn, cb_data);
1914 release_packed_ref_cache(packed_ref_cache);
1915 return retval;
1919 * Call fn for each reference in the specified ref_cache for which the
1920 * refname begins with base. If trim is non-zero, then trim that many
1921 * characters off the beginning of each refname before passing the
1922 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1923 * broken references in the iteration. If fn ever returns a non-zero
1924 * value, stop the iteration and return that value; otherwise, return
1925 * 0.
1927 static int do_for_each_ref(struct ref_cache *refs, const char *base,
1928 each_ref_fn fn, int trim, int flags, void *cb_data)
1930 struct ref_entry_cb data;
1931 data.base = base;
1932 data.trim = trim;
1933 data.flags = flags;
1934 data.fn = fn;
1935 data.cb_data = cb_data;
1937 return do_for_each_entry(refs, base, do_one_ref, &data);
1940 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1942 unsigned char sha1[20];
1943 int flag;
1945 if (submodule) {
1946 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
1947 return fn("HEAD", sha1, 0, cb_data);
1949 return 0;
1952 if (!read_ref_full("HEAD", RESOLVE_REF_READING, sha1, &flag))
1953 return fn("HEAD", sha1, flag, cb_data);
1955 return 0;
1958 int head_ref(each_ref_fn fn, void *cb_data)
1960 return do_head_ref(NULL, fn, cb_data);
1963 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1965 return do_head_ref(submodule, fn, cb_data);
1968 int for_each_ref(each_ref_fn fn, void *cb_data)
1970 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
1973 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1975 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
1978 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1980 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
1983 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1984 each_ref_fn fn, void *cb_data)
1986 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
1989 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
1991 return for_each_ref_in("refs/tags/", fn, cb_data);
1994 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1996 return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
1999 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
2001 return for_each_ref_in("refs/heads/", fn, cb_data);
2004 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2006 return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
2009 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
2011 return for_each_ref_in("refs/remotes/", fn, cb_data);
2014 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2016 return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
2019 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
2021 return do_for_each_ref(&ref_cache, "refs/replace/", fn, 13, 0, cb_data);
2024 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
2026 struct strbuf buf = STRBUF_INIT;
2027 int ret = 0;
2028 unsigned char sha1[20];
2029 int flag;
2031 strbuf_addf(&buf, "%sHEAD", get_git_namespace());
2032 if (!read_ref_full(buf.buf, RESOLVE_REF_READING, sha1, &flag))
2033 ret = fn(buf.buf, sha1, flag, cb_data);
2034 strbuf_release(&buf);
2036 return ret;
2039 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
2041 struct strbuf buf = STRBUF_INIT;
2042 int ret;
2043 strbuf_addf(&buf, "%srefs/", get_git_namespace());
2044 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
2045 strbuf_release(&buf);
2046 return ret;
2049 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
2050 const char *prefix, void *cb_data)
2052 struct strbuf real_pattern = STRBUF_INIT;
2053 struct ref_filter filter;
2054 int ret;
2056 if (!prefix && !starts_with(pattern, "refs/"))
2057 strbuf_addstr(&real_pattern, "refs/");
2058 else if (prefix)
2059 strbuf_addstr(&real_pattern, prefix);
2060 strbuf_addstr(&real_pattern, pattern);
2062 if (!has_glob_specials(pattern)) {
2063 /* Append implied '/' '*' if not present. */
2064 if (real_pattern.buf[real_pattern.len - 1] != '/')
2065 strbuf_addch(&real_pattern, '/');
2066 /* No need to check for '*', there is none. */
2067 strbuf_addch(&real_pattern, '*');
2070 filter.pattern = real_pattern.buf;
2071 filter.fn = fn;
2072 filter.cb_data = cb_data;
2073 ret = for_each_ref(filter_refs, &filter);
2075 strbuf_release(&real_pattern);
2076 return ret;
2079 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
2081 return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
2084 int for_each_rawref(each_ref_fn fn, void *cb_data)
2086 return do_for_each_ref(&ref_cache, "", fn, 0,
2087 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
2090 const char *prettify_refname(const char *name)
2092 return name + (
2093 starts_with(name, "refs/heads/") ? 11 :
2094 starts_with(name, "refs/tags/") ? 10 :
2095 starts_with(name, "refs/remotes/") ? 13 :
2099 static const char *ref_rev_parse_rules[] = {
2100 "%.*s",
2101 "refs/%.*s",
2102 "refs/tags/%.*s",
2103 "refs/heads/%.*s",
2104 "refs/remotes/%.*s",
2105 "refs/remotes/%.*s/HEAD",
2106 NULL
2109 int refname_match(const char *abbrev_name, const char *full_name)
2111 const char **p;
2112 const int abbrev_name_len = strlen(abbrev_name);
2114 for (p = ref_rev_parse_rules; *p; p++) {
2115 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
2116 return 1;
2120 return 0;
2123 static void unlock_ref(struct ref_lock *lock)
2125 /* Do not free lock->lk -- atexit() still looks at them */
2126 if (lock->lk)
2127 rollback_lock_file(lock->lk);
2128 free(lock->ref_name);
2129 free(lock->orig_ref_name);
2130 free(lock);
2133 /* This function should make sure errno is meaningful on error */
2134 static struct ref_lock *verify_lock(struct ref_lock *lock,
2135 const unsigned char *old_sha1, int mustexist)
2137 if (read_ref_full(lock->ref_name,
2138 mustexist ? RESOLVE_REF_READING : 0,
2139 lock->old_sha1, NULL)) {
2140 int save_errno = errno;
2141 error("Can't verify ref %s", lock->ref_name);
2142 unlock_ref(lock);
2143 errno = save_errno;
2144 return NULL;
2146 if (hashcmp(lock->old_sha1, old_sha1)) {
2147 error("Ref %s is at %s but expected %s", lock->ref_name,
2148 sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
2149 unlock_ref(lock);
2150 errno = EBUSY;
2151 return NULL;
2153 return lock;
2156 static int remove_empty_directories(const char *file)
2158 /* we want to create a file but there is a directory there;
2159 * if that is an empty directory (or a directory that contains
2160 * only empty directories), remove them.
2162 struct strbuf path;
2163 int result, save_errno;
2165 strbuf_init(&path, 20);
2166 strbuf_addstr(&path, file);
2168 result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
2169 save_errno = errno;
2171 strbuf_release(&path);
2172 errno = save_errno;
2174 return result;
2178 * *string and *len will only be substituted, and *string returned (for
2179 * later free()ing) if the string passed in is a magic short-hand form
2180 * to name a branch.
2182 static char *substitute_branch_name(const char **string, int *len)
2184 struct strbuf buf = STRBUF_INIT;
2185 int ret = interpret_branch_name(*string, *len, &buf);
2187 if (ret == *len) {
2188 size_t size;
2189 *string = strbuf_detach(&buf, &size);
2190 *len = size;
2191 return (char *)*string;
2194 return NULL;
2197 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
2199 char *last_branch = substitute_branch_name(&str, &len);
2200 const char **p, *r;
2201 int refs_found = 0;
2203 *ref = NULL;
2204 for (p = ref_rev_parse_rules; *p; p++) {
2205 char fullref[PATH_MAX];
2206 unsigned char sha1_from_ref[20];
2207 unsigned char *this_result;
2208 int flag;
2210 this_result = refs_found ? sha1_from_ref : sha1;
2211 mksnpath(fullref, sizeof(fullref), *p, len, str);
2212 r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
2213 this_result, &flag);
2214 if (r) {
2215 if (!refs_found++)
2216 *ref = xstrdup(r);
2217 if (!warn_ambiguous_refs)
2218 break;
2219 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
2220 warning("ignoring dangling symref %s.", fullref);
2221 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
2222 warning("ignoring broken ref %s.", fullref);
2225 free(last_branch);
2226 return refs_found;
2229 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
2231 char *last_branch = substitute_branch_name(&str, &len);
2232 const char **p;
2233 int logs_found = 0;
2235 *log = NULL;
2236 for (p = ref_rev_parse_rules; *p; p++) {
2237 unsigned char hash[20];
2238 char path[PATH_MAX];
2239 const char *ref, *it;
2241 mksnpath(path, sizeof(path), *p, len, str);
2242 ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
2243 hash, NULL);
2244 if (!ref)
2245 continue;
2246 if (reflog_exists(path))
2247 it = path;
2248 else if (strcmp(ref, path) && reflog_exists(ref))
2249 it = ref;
2250 else
2251 continue;
2252 if (!logs_found++) {
2253 *log = xstrdup(it);
2254 hashcpy(sha1, hash);
2256 if (!warn_ambiguous_refs)
2257 break;
2259 free(last_branch);
2260 return logs_found;
2264 * Locks a ref returning the lock on success and NULL on failure.
2265 * On failure errno is set to something meaningful.
2267 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2268 const unsigned char *old_sha1,
2269 const struct string_list *skip,
2270 unsigned int flags, int *type_p)
2272 char *ref_file;
2273 const char *orig_refname = refname;
2274 struct ref_lock *lock;
2275 int last_errno = 0;
2276 int type, lflags;
2277 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
2278 int resolve_flags = 0;
2279 int attempts_remaining = 3;
2281 lock = xcalloc(1, sizeof(struct ref_lock));
2282 lock->lock_fd = -1;
2284 if (mustexist)
2285 resolve_flags |= RESOLVE_REF_READING;
2286 if (flags & REF_DELETING) {
2287 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
2288 if (flags & REF_NODEREF)
2289 resolve_flags |= RESOLVE_REF_NO_RECURSE;
2292 refname = resolve_ref_unsafe(refname, resolve_flags,
2293 lock->old_sha1, &type);
2294 if (!refname && errno == EISDIR) {
2295 /* we are trying to lock foo but we used to
2296 * have foo/bar which now does not exist;
2297 * it is normal for the empty directory 'foo'
2298 * to remain.
2300 ref_file = git_path("%s", orig_refname);
2301 if (remove_empty_directories(ref_file)) {
2302 last_errno = errno;
2303 error("there are still refs under '%s'", orig_refname);
2304 goto error_return;
2306 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
2307 lock->old_sha1, &type);
2309 if (type_p)
2310 *type_p = type;
2311 if (!refname) {
2312 last_errno = errno;
2313 error("unable to resolve reference %s: %s",
2314 orig_refname, strerror(errno));
2315 goto error_return;
2318 * If the ref did not exist and we are creating it, make sure
2319 * there is no existing packed ref whose name begins with our
2320 * refname, nor a packed ref whose name is a proper prefix of
2321 * our refname.
2323 if (is_null_sha1(lock->old_sha1) &&
2324 !is_refname_available(refname, skip, get_packed_refs(&ref_cache))) {
2325 last_errno = ENOTDIR;
2326 goto error_return;
2329 lock->lk = xcalloc(1, sizeof(struct lock_file));
2331 lflags = 0;
2332 if (flags & REF_NODEREF) {
2333 refname = orig_refname;
2334 lflags |= LOCK_NO_DEREF;
2336 lock->ref_name = xstrdup(refname);
2337 lock->orig_ref_name = xstrdup(orig_refname);
2338 ref_file = git_path("%s", refname);
2340 retry:
2341 switch (safe_create_leading_directories(ref_file)) {
2342 case SCLD_OK:
2343 break; /* success */
2344 case SCLD_VANISHED:
2345 if (--attempts_remaining > 0)
2346 goto retry;
2347 /* fall through */
2348 default:
2349 last_errno = errno;
2350 error("unable to create directory for %s", ref_file);
2351 goto error_return;
2354 lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
2355 if (lock->lock_fd < 0) {
2356 last_errno = errno;
2357 if (errno == ENOENT && --attempts_remaining > 0)
2359 * Maybe somebody just deleted one of the
2360 * directories leading to ref_file. Try
2361 * again:
2363 goto retry;
2364 else {
2365 struct strbuf err = STRBUF_INIT;
2366 unable_to_lock_message(ref_file, errno, &err);
2367 error("%s", err.buf);
2368 strbuf_release(&err);
2369 goto error_return;
2372 return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
2374 error_return:
2375 unlock_ref(lock);
2376 errno = last_errno;
2377 return NULL;
2381 * Write an entry to the packed-refs file for the specified refname.
2382 * If peeled is non-NULL, write it as the entry's peeled value.
2384 static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2385 unsigned char *peeled)
2387 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2388 if (peeled)
2389 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2393 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2395 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2397 enum peel_status peel_status = peel_entry(entry, 0);
2399 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2400 error("internal error: %s is not a valid packed reference!",
2401 entry->name);
2402 write_packed_entry(cb_data, entry->name, entry->u.value.sha1,
2403 peel_status == PEEL_PEELED ?
2404 entry->u.value.peeled : NULL);
2405 return 0;
2408 /* This should return a meaningful errno on failure */
2409 int lock_packed_refs(int flags)
2411 struct packed_ref_cache *packed_ref_cache;
2413 if (hold_lock_file_for_update(&packlock, git_path("packed-refs"), flags) < 0)
2414 return -1;
2416 * Get the current packed-refs while holding the lock. If the
2417 * packed-refs file has been modified since we last read it,
2418 * this will automatically invalidate the cache and re-read
2419 * the packed-refs file.
2421 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2422 packed_ref_cache->lock = &packlock;
2423 /* Increment the reference count to prevent it from being freed: */
2424 acquire_packed_ref_cache(packed_ref_cache);
2425 return 0;
2429 * Commit the packed refs changes.
2430 * On error we must make sure that errno contains a meaningful value.
2432 int commit_packed_refs(void)
2434 struct packed_ref_cache *packed_ref_cache =
2435 get_packed_ref_cache(&ref_cache);
2436 int error = 0;
2437 int save_errno = 0;
2438 FILE *out;
2440 if (!packed_ref_cache->lock)
2441 die("internal error: packed-refs not locked");
2443 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2444 if (!out)
2445 die_errno("unable to fdopen packed-refs descriptor");
2447 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2448 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2449 0, write_packed_entry_fn, out);
2451 if (commit_lock_file(packed_ref_cache->lock)) {
2452 save_errno = errno;
2453 error = -1;
2455 packed_ref_cache->lock = NULL;
2456 release_packed_ref_cache(packed_ref_cache);
2457 errno = save_errno;
2458 return error;
2461 void rollback_packed_refs(void)
2463 struct packed_ref_cache *packed_ref_cache =
2464 get_packed_ref_cache(&ref_cache);
2466 if (!packed_ref_cache->lock)
2467 die("internal error: packed-refs not locked");
2468 rollback_lock_file(packed_ref_cache->lock);
2469 packed_ref_cache->lock = NULL;
2470 release_packed_ref_cache(packed_ref_cache);
2471 clear_packed_ref_cache(&ref_cache);
2474 struct ref_to_prune {
2475 struct ref_to_prune *next;
2476 unsigned char sha1[20];
2477 char name[FLEX_ARRAY];
2480 struct pack_refs_cb_data {
2481 unsigned int flags;
2482 struct ref_dir *packed_refs;
2483 struct ref_to_prune *ref_to_prune;
2487 * An each_ref_entry_fn that is run over loose references only. If
2488 * the loose reference can be packed, add an entry in the packed ref
2489 * cache. If the reference should be pruned, also add it to
2490 * ref_to_prune in the pack_refs_cb_data.
2492 static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2494 struct pack_refs_cb_data *cb = cb_data;
2495 enum peel_status peel_status;
2496 struct ref_entry *packed_entry;
2497 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2499 /* ALWAYS pack tags */
2500 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2501 return 0;
2503 /* Do not pack symbolic or broken refs: */
2504 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2505 return 0;
2507 /* Add a packed ref cache entry equivalent to the loose entry. */
2508 peel_status = peel_entry(entry, 1);
2509 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2510 die("internal error peeling reference %s (%s)",
2511 entry->name, sha1_to_hex(entry->u.value.sha1));
2512 packed_entry = find_ref(cb->packed_refs, entry->name);
2513 if (packed_entry) {
2514 /* Overwrite existing packed entry with info from loose entry */
2515 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2516 hashcpy(packed_entry->u.value.sha1, entry->u.value.sha1);
2517 } else {
2518 packed_entry = create_ref_entry(entry->name, entry->u.value.sha1,
2519 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2520 add_ref(cb->packed_refs, packed_entry);
2522 hashcpy(packed_entry->u.value.peeled, entry->u.value.peeled);
2524 /* Schedule the loose reference for pruning if requested. */
2525 if ((cb->flags & PACK_REFS_PRUNE)) {
2526 int namelen = strlen(entry->name) + 1;
2527 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2528 hashcpy(n->sha1, entry->u.value.sha1);
2529 strcpy(n->name, entry->name);
2530 n->next = cb->ref_to_prune;
2531 cb->ref_to_prune = n;
2533 return 0;
2537 * Remove empty parents, but spare refs/ and immediate subdirs.
2538 * Note: munges *name.
2540 static void try_remove_empty_parents(char *name)
2542 char *p, *q;
2543 int i;
2544 p = name;
2545 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2546 while (*p && *p != '/')
2547 p++;
2548 /* tolerate duplicate slashes; see check_refname_format() */
2549 while (*p == '/')
2550 p++;
2552 for (q = p; *q; q++)
2554 while (1) {
2555 while (q > p && *q != '/')
2556 q--;
2557 while (q > p && *(q-1) == '/')
2558 q--;
2559 if (q == p)
2560 break;
2561 *q = '\0';
2562 if (rmdir(git_path("%s", name)))
2563 break;
2567 /* make sure nobody touched the ref, and unlink */
2568 static void prune_ref(struct ref_to_prune *r)
2570 struct ref_transaction *transaction;
2571 struct strbuf err = STRBUF_INIT;
2573 if (check_refname_format(r->name, 0))
2574 return;
2576 transaction = ref_transaction_begin(&err);
2577 if (!transaction ||
2578 ref_transaction_delete(transaction, r->name, r->sha1,
2579 REF_ISPRUNING, NULL, &err) ||
2580 ref_transaction_commit(transaction, &err)) {
2581 ref_transaction_free(transaction);
2582 error("%s", err.buf);
2583 strbuf_release(&err);
2584 return;
2586 ref_transaction_free(transaction);
2587 strbuf_release(&err);
2588 try_remove_empty_parents(r->name);
2591 static void prune_refs(struct ref_to_prune *r)
2593 while (r) {
2594 prune_ref(r);
2595 r = r->next;
2599 int pack_refs(unsigned int flags)
2601 struct pack_refs_cb_data cbdata;
2603 memset(&cbdata, 0, sizeof(cbdata));
2604 cbdata.flags = flags;
2606 lock_packed_refs(LOCK_DIE_ON_ERROR);
2607 cbdata.packed_refs = get_packed_refs(&ref_cache);
2609 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2610 pack_if_possible_fn, &cbdata);
2612 if (commit_packed_refs())
2613 die_errno("unable to overwrite old ref-pack file");
2615 prune_refs(cbdata.ref_to_prune);
2616 return 0;
2620 * If entry is no longer needed in packed-refs, add it to the string
2621 * list pointed to by cb_data. Reasons for deleting entries:
2623 * - Entry is broken.
2624 * - Entry is overridden by a loose ref.
2625 * - Entry does not point at a valid object.
2627 * In the first and third cases, also emit an error message because these
2628 * are indications of repository corruption.
2630 static int curate_packed_ref_fn(struct ref_entry *entry, void *cb_data)
2632 struct string_list *refs_to_delete = cb_data;
2634 if (entry->flag & REF_ISBROKEN) {
2635 /* This shouldn't happen to packed refs. */
2636 error("%s is broken!", entry->name);
2637 string_list_append(refs_to_delete, entry->name);
2638 return 0;
2640 if (!has_sha1_file(entry->u.value.sha1)) {
2641 unsigned char sha1[20];
2642 int flags;
2644 if (read_ref_full(entry->name, 0, sha1, &flags))
2645 /* We should at least have found the packed ref. */
2646 die("Internal error");
2647 if ((flags & REF_ISSYMREF) || !(flags & REF_ISPACKED)) {
2649 * This packed reference is overridden by a
2650 * loose reference, so it is OK that its value
2651 * is no longer valid; for example, it might
2652 * refer to an object that has been garbage
2653 * collected. For this purpose we don't even
2654 * care whether the loose reference itself is
2655 * invalid, broken, symbolic, etc. Silently
2656 * remove the packed reference.
2658 string_list_append(refs_to_delete, entry->name);
2659 return 0;
2662 * There is no overriding loose reference, so the fact
2663 * that this reference doesn't refer to a valid object
2664 * indicates some kind of repository corruption.
2665 * Report the problem, then omit the reference from
2666 * the output.
2668 error("%s does not point to a valid object!", entry->name);
2669 string_list_append(refs_to_delete, entry->name);
2670 return 0;
2673 return 0;
2676 int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2678 struct ref_dir *packed;
2679 struct string_list refs_to_delete = STRING_LIST_INIT_DUP;
2680 struct string_list_item *refname, *ref_to_delete;
2681 int ret, needs_repacking = 0, removed = 0;
2683 assert(err);
2685 /* Look for a packed ref */
2686 for_each_string_list_item(refname, refnames) {
2687 if (get_packed_ref(refname->string)) {
2688 needs_repacking = 1;
2689 break;
2693 /* Avoid locking if we have nothing to do */
2694 if (!needs_repacking)
2695 return 0; /* no refname exists in packed refs */
2697 if (lock_packed_refs(0)) {
2698 unable_to_lock_message(git_path("packed-refs"), errno, err);
2699 return -1;
2701 packed = get_packed_refs(&ref_cache);
2703 /* Remove refnames from the cache */
2704 for_each_string_list_item(refname, refnames)
2705 if (remove_entry(packed, refname->string) != -1)
2706 removed = 1;
2707 if (!removed) {
2709 * All packed entries disappeared while we were
2710 * acquiring the lock.
2712 rollback_packed_refs();
2713 return 0;
2716 /* Remove any other accumulated cruft */
2717 do_for_each_entry_in_dir(packed, 0, curate_packed_ref_fn, &refs_to_delete);
2718 for_each_string_list_item(ref_to_delete, &refs_to_delete) {
2719 if (remove_entry(packed, ref_to_delete->string) == -1)
2720 die("internal error");
2723 /* Write what remains */
2724 ret = commit_packed_refs();
2725 if (ret)
2726 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2727 strerror(errno));
2728 return ret;
2731 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2733 assert(err);
2735 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2737 * loose. The loose file name is the same as the
2738 * lockfile name, minus ".lock":
2740 char *loose_filename = get_locked_file_path(lock->lk);
2741 int res = unlink_or_msg(loose_filename, err);
2742 free(loose_filename);
2743 if (res)
2744 return 1;
2746 return 0;
2749 int delete_ref(const char *refname, const unsigned char *sha1, unsigned int flags)
2751 struct ref_transaction *transaction;
2752 struct strbuf err = STRBUF_INIT;
2754 transaction = ref_transaction_begin(&err);
2755 if (!transaction ||
2756 ref_transaction_delete(transaction, refname,
2757 (sha1 && !is_null_sha1(sha1)) ? sha1 : NULL,
2758 flags, NULL, &err) ||
2759 ref_transaction_commit(transaction, &err)) {
2760 error("%s", err.buf);
2761 ref_transaction_free(transaction);
2762 strbuf_release(&err);
2763 return 1;
2765 ref_transaction_free(transaction);
2766 strbuf_release(&err);
2767 return 0;
2771 * People using contrib's git-new-workdir have .git/logs/refs ->
2772 * /some/other/path/.git/logs/refs, and that may live on another device.
2774 * IOW, to avoid cross device rename errors, the temporary renamed log must
2775 * live into logs/refs.
2777 #define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2779 static int rename_tmp_log(const char *newrefname)
2781 int attempts_remaining = 4;
2783 retry:
2784 switch (safe_create_leading_directories(git_path("logs/%s", newrefname))) {
2785 case SCLD_OK:
2786 break; /* success */
2787 case SCLD_VANISHED:
2788 if (--attempts_remaining > 0)
2789 goto retry;
2790 /* fall through */
2791 default:
2792 error("unable to create directory for %s", newrefname);
2793 return -1;
2796 if (rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
2797 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2799 * rename(a, b) when b is an existing
2800 * directory ought to result in ISDIR, but
2801 * Solaris 5.8 gives ENOTDIR. Sheesh.
2803 if (remove_empty_directories(git_path("logs/%s", newrefname))) {
2804 error("Directory not empty: logs/%s", newrefname);
2805 return -1;
2807 goto retry;
2808 } else if (errno == ENOENT && --attempts_remaining > 0) {
2810 * Maybe another process just deleted one of
2811 * the directories in the path to newrefname.
2812 * Try again from the beginning.
2814 goto retry;
2815 } else {
2816 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2817 newrefname, strerror(errno));
2818 return -1;
2821 return 0;
2824 static int rename_ref_available(const char *oldname, const char *newname)
2826 struct string_list skip = STRING_LIST_INIT_NODUP;
2827 int ret;
2829 string_list_insert(&skip, oldname);
2830 ret = is_refname_available(newname, &skip, get_packed_refs(&ref_cache))
2831 && is_refname_available(newname, &skip, get_loose_refs(&ref_cache));
2832 string_list_clear(&skip, 0);
2833 return ret;
2836 static int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1,
2837 const char *logmsg);
2839 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2841 unsigned char sha1[20], orig_sha1[20];
2842 int flag = 0, logmoved = 0;
2843 struct ref_lock *lock;
2844 struct stat loginfo;
2845 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
2846 const char *symref = NULL;
2848 if (log && S_ISLNK(loginfo.st_mode))
2849 return error("reflog for %s is a symlink", oldrefname);
2851 symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
2852 orig_sha1, &flag);
2853 if (flag & REF_ISSYMREF)
2854 return error("refname %s is a symbolic ref, renaming it is not supported",
2855 oldrefname);
2856 if (!symref)
2857 return error("refname %s not found", oldrefname);
2859 if (!rename_ref_available(oldrefname, newrefname))
2860 return 1;
2862 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2863 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2864 oldrefname, strerror(errno));
2866 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2867 error("unable to delete old %s", oldrefname);
2868 goto rollback;
2871 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
2872 delete_ref(newrefname, sha1, REF_NODEREF)) {
2873 if (errno==EISDIR) {
2874 if (remove_empty_directories(git_path("%s", newrefname))) {
2875 error("Directory not empty: %s", newrefname);
2876 goto rollback;
2878 } else {
2879 error("unable to delete existing %s", newrefname);
2880 goto rollback;
2884 if (log && rename_tmp_log(newrefname))
2885 goto rollback;
2887 logmoved = log;
2889 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, 0, NULL);
2890 if (!lock) {
2891 error("unable to lock %s for update", newrefname);
2892 goto rollback;
2894 hashcpy(lock->old_sha1, orig_sha1);
2895 if (write_ref_sha1(lock, orig_sha1, logmsg)) {
2896 error("unable to write current sha1 into %s", newrefname);
2897 goto rollback;
2900 return 0;
2902 rollback:
2903 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, 0, NULL);
2904 if (!lock) {
2905 error("unable to lock %s for rollback", oldrefname);
2906 goto rollbacklog;
2909 flag = log_all_ref_updates;
2910 log_all_ref_updates = 0;
2911 if (write_ref_sha1(lock, orig_sha1, NULL))
2912 error("unable to write current sha1 into %s", oldrefname);
2913 log_all_ref_updates = flag;
2915 rollbacklog:
2916 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2917 error("unable to restore logfile %s from %s: %s",
2918 oldrefname, newrefname, strerror(errno));
2919 if (!logmoved && log &&
2920 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2921 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2922 oldrefname, strerror(errno));
2924 return 1;
2927 static int close_ref(struct ref_lock *lock)
2929 if (close_lock_file(lock->lk))
2930 return -1;
2931 lock->lock_fd = -1;
2932 return 0;
2935 static int commit_ref(struct ref_lock *lock)
2937 if (commit_lock_file(lock->lk))
2938 return -1;
2939 lock->lock_fd = -1;
2940 return 0;
2944 * copy the reflog message msg to buf, which has been allocated sufficiently
2945 * large, while cleaning up the whitespaces. Especially, convert LF to space,
2946 * because reflog file is one line per entry.
2948 static int copy_msg(char *buf, const char *msg)
2950 char *cp = buf;
2951 char c;
2952 int wasspace = 1;
2954 *cp++ = '\t';
2955 while ((c = *msg++)) {
2956 if (wasspace && isspace(c))
2957 continue;
2958 wasspace = isspace(c);
2959 if (wasspace)
2960 c = ' ';
2961 *cp++ = c;
2963 while (buf < cp && isspace(cp[-1]))
2964 cp--;
2965 *cp++ = '\n';
2966 return cp - buf;
2969 /* This function must set a meaningful errno on failure */
2970 int log_ref_setup(const char *refname, char *logfile, int bufsize)
2972 int logfd, oflags = O_APPEND | O_WRONLY;
2974 git_snpath(logfile, bufsize, "logs/%s", refname);
2975 if (log_all_ref_updates &&
2976 (starts_with(refname, "refs/heads/") ||
2977 starts_with(refname, "refs/remotes/") ||
2978 starts_with(refname, "refs/notes/") ||
2979 !strcmp(refname, "HEAD"))) {
2980 if (safe_create_leading_directories(logfile) < 0) {
2981 int save_errno = errno;
2982 error("unable to create directory for %s", logfile);
2983 errno = save_errno;
2984 return -1;
2986 oflags |= O_CREAT;
2989 logfd = open(logfile, oflags, 0666);
2990 if (logfd < 0) {
2991 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
2992 return 0;
2994 if (errno == EISDIR) {
2995 if (remove_empty_directories(logfile)) {
2996 int save_errno = errno;
2997 error("There are still logs under '%s'",
2998 logfile);
2999 errno = save_errno;
3000 return -1;
3002 logfd = open(logfile, oflags, 0666);
3005 if (logfd < 0) {
3006 int save_errno = errno;
3007 error("Unable to append to %s: %s", logfile,
3008 strerror(errno));
3009 errno = save_errno;
3010 return -1;
3014 adjust_shared_perm(logfile);
3015 close(logfd);
3016 return 0;
3019 static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
3020 const unsigned char *new_sha1,
3021 const char *committer, const char *msg)
3023 int msglen, written;
3024 unsigned maxlen, len;
3025 char *logrec;
3027 msglen = msg ? strlen(msg) : 0;
3028 maxlen = strlen(committer) + msglen + 100;
3029 logrec = xmalloc(maxlen);
3030 len = sprintf(logrec, "%s %s %s\n",
3031 sha1_to_hex(old_sha1),
3032 sha1_to_hex(new_sha1),
3033 committer);
3034 if (msglen)
3035 len += copy_msg(logrec + len - 1, msg) - 1;
3037 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
3038 free(logrec);
3039 if (written != len)
3040 return -1;
3042 return 0;
3045 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
3046 const unsigned char *new_sha1, const char *msg)
3048 int logfd, result, oflags = O_APPEND | O_WRONLY;
3049 char log_file[PATH_MAX];
3051 if (log_all_ref_updates < 0)
3052 log_all_ref_updates = !is_bare_repository();
3054 result = log_ref_setup(refname, log_file, sizeof(log_file));
3055 if (result)
3056 return result;
3058 logfd = open(log_file, oflags);
3059 if (logfd < 0)
3060 return 0;
3061 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
3062 git_committer_info(0), msg);
3063 if (result) {
3064 int save_errno = errno;
3065 close(logfd);
3066 error("Unable to append to %s", log_file);
3067 errno = save_errno;
3068 return -1;
3070 if (close(logfd)) {
3071 int save_errno = errno;
3072 error("Unable to append to %s", log_file);
3073 errno = save_errno;
3074 return -1;
3076 return 0;
3079 int is_branch(const char *refname)
3081 return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
3085 * Write sha1 into the ref specified by the lock. Make sure that errno
3086 * is sane on error.
3088 static int write_ref_sha1(struct ref_lock *lock,
3089 const unsigned char *sha1, const char *logmsg)
3091 static char term = '\n';
3092 struct object *o;
3094 o = parse_object(sha1);
3095 if (!o) {
3096 error("Trying to write ref %s with nonexistent object %s",
3097 lock->ref_name, sha1_to_hex(sha1));
3098 unlock_ref(lock);
3099 errno = EINVAL;
3100 return -1;
3102 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
3103 error("Trying to write non-commit object %s to branch %s",
3104 sha1_to_hex(sha1), lock->ref_name);
3105 unlock_ref(lock);
3106 errno = EINVAL;
3107 return -1;
3109 if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
3110 write_in_full(lock->lock_fd, &term, 1) != 1 ||
3111 close_ref(lock) < 0) {
3112 int save_errno = errno;
3113 error("Couldn't write %s", lock->lk->filename.buf);
3114 unlock_ref(lock);
3115 errno = save_errno;
3116 return -1;
3118 clear_loose_ref_cache(&ref_cache);
3119 if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
3120 (strcmp(lock->ref_name, lock->orig_ref_name) &&
3121 log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
3122 unlock_ref(lock);
3123 return -1;
3125 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
3127 * Special hack: If a branch is updated directly and HEAD
3128 * points to it (may happen on the remote side of a push
3129 * for example) then logically the HEAD reflog should be
3130 * updated too.
3131 * A generic solution implies reverse symref information,
3132 * but finding all symrefs pointing to the given branch
3133 * would be rather costly for this rare event (the direct
3134 * update of a branch) to be worth it. So let's cheat and
3135 * check with HEAD only which should cover 99% of all usage
3136 * scenarios (even 100% of the default ones).
3138 unsigned char head_sha1[20];
3139 int head_flag;
3140 const char *head_ref;
3141 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3142 head_sha1, &head_flag);
3143 if (head_ref && (head_flag & REF_ISSYMREF) &&
3144 !strcmp(head_ref, lock->ref_name))
3145 log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
3147 if (commit_ref(lock)) {
3148 error("Couldn't set %s", lock->ref_name);
3149 unlock_ref(lock);
3150 return -1;
3152 unlock_ref(lock);
3153 return 0;
3156 int create_symref(const char *ref_target, const char *refs_heads_master,
3157 const char *logmsg)
3159 const char *lockpath;
3160 char ref[1000];
3161 int fd, len, written;
3162 char *git_HEAD = git_pathdup("%s", ref_target);
3163 unsigned char old_sha1[20], new_sha1[20];
3165 if (logmsg && read_ref(ref_target, old_sha1))
3166 hashclr(old_sha1);
3168 if (safe_create_leading_directories(git_HEAD) < 0)
3169 return error("unable to create directory for %s", git_HEAD);
3171 #ifndef NO_SYMLINK_HEAD
3172 if (prefer_symlink_refs) {
3173 unlink(git_HEAD);
3174 if (!symlink(refs_heads_master, git_HEAD))
3175 goto done;
3176 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
3178 #endif
3180 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
3181 if (sizeof(ref) <= len) {
3182 error("refname too long: %s", refs_heads_master);
3183 goto error_free_return;
3185 lockpath = mkpath("%s.lock", git_HEAD);
3186 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
3187 if (fd < 0) {
3188 error("Unable to open %s for writing", lockpath);
3189 goto error_free_return;
3191 written = write_in_full(fd, ref, len);
3192 if (close(fd) != 0 || written != len) {
3193 error("Unable to write to %s", lockpath);
3194 goto error_unlink_return;
3196 if (rename(lockpath, git_HEAD) < 0) {
3197 error("Unable to create %s", git_HEAD);
3198 goto error_unlink_return;
3200 if (adjust_shared_perm(git_HEAD)) {
3201 error("Unable to fix permissions on %s", lockpath);
3202 error_unlink_return:
3203 unlink_or_warn(lockpath);
3204 error_free_return:
3205 free(git_HEAD);
3206 return -1;
3209 #ifndef NO_SYMLINK_HEAD
3210 done:
3211 #endif
3212 if (logmsg && !read_ref(refs_heads_master, new_sha1))
3213 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
3215 free(git_HEAD);
3216 return 0;
3219 struct read_ref_at_cb {
3220 const char *refname;
3221 unsigned long at_time;
3222 int cnt;
3223 int reccnt;
3224 unsigned char *sha1;
3225 int found_it;
3227 unsigned char osha1[20];
3228 unsigned char nsha1[20];
3229 int tz;
3230 unsigned long date;
3231 char **msg;
3232 unsigned long *cutoff_time;
3233 int *cutoff_tz;
3234 int *cutoff_cnt;
3237 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
3238 const char *email, unsigned long timestamp, int tz,
3239 const char *message, void *cb_data)
3241 struct read_ref_at_cb *cb = cb_data;
3243 cb->reccnt++;
3244 cb->tz = tz;
3245 cb->date = timestamp;
3247 if (timestamp <= cb->at_time || cb->cnt == 0) {
3248 if (cb->msg)
3249 *cb->msg = xstrdup(message);
3250 if (cb->cutoff_time)
3251 *cb->cutoff_time = timestamp;
3252 if (cb->cutoff_tz)
3253 *cb->cutoff_tz = tz;
3254 if (cb->cutoff_cnt)
3255 *cb->cutoff_cnt = cb->reccnt - 1;
3257 * we have not yet updated cb->[n|o]sha1 so they still
3258 * hold the values for the previous record.
3260 if (!is_null_sha1(cb->osha1)) {
3261 hashcpy(cb->sha1, nsha1);
3262 if (hashcmp(cb->osha1, nsha1))
3263 warning("Log for ref %s has gap after %s.",
3264 cb->refname, show_date(cb->date, cb->tz, DATE_RFC2822));
3266 else if (cb->date == cb->at_time)
3267 hashcpy(cb->sha1, nsha1);
3268 else if (hashcmp(nsha1, cb->sha1))
3269 warning("Log for ref %s unexpectedly ended on %s.",
3270 cb->refname, show_date(cb->date, cb->tz,
3271 DATE_RFC2822));
3272 hashcpy(cb->osha1, osha1);
3273 hashcpy(cb->nsha1, nsha1);
3274 cb->found_it = 1;
3275 return 1;
3277 hashcpy(cb->osha1, osha1);
3278 hashcpy(cb->nsha1, nsha1);
3279 if (cb->cnt > 0)
3280 cb->cnt--;
3281 return 0;
3284 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
3285 const char *email, unsigned long timestamp,
3286 int tz, const char *message, void *cb_data)
3288 struct read_ref_at_cb *cb = cb_data;
3290 if (cb->msg)
3291 *cb->msg = xstrdup(message);
3292 if (cb->cutoff_time)
3293 *cb->cutoff_time = timestamp;
3294 if (cb->cutoff_tz)
3295 *cb->cutoff_tz = tz;
3296 if (cb->cutoff_cnt)
3297 *cb->cutoff_cnt = cb->reccnt;
3298 hashcpy(cb->sha1, osha1);
3299 if (is_null_sha1(cb->sha1))
3300 hashcpy(cb->sha1, nsha1);
3301 /* We just want the first entry */
3302 return 1;
3305 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
3306 unsigned char *sha1, char **msg,
3307 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
3309 struct read_ref_at_cb cb;
3311 memset(&cb, 0, sizeof(cb));
3312 cb.refname = refname;
3313 cb.at_time = at_time;
3314 cb.cnt = cnt;
3315 cb.msg = msg;
3316 cb.cutoff_time = cutoff_time;
3317 cb.cutoff_tz = cutoff_tz;
3318 cb.cutoff_cnt = cutoff_cnt;
3319 cb.sha1 = sha1;
3321 for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
3323 if (!cb.reccnt) {
3324 if (flags & GET_SHA1_QUIETLY)
3325 exit(128);
3326 else
3327 die("Log for %s is empty.", refname);
3329 if (cb.found_it)
3330 return 0;
3332 for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
3334 return 1;
3337 int reflog_exists(const char *refname)
3339 struct stat st;
3341 return !lstat(git_path("logs/%s", refname), &st) &&
3342 S_ISREG(st.st_mode);
3345 int delete_reflog(const char *refname)
3347 return remove_path(git_path("logs/%s", refname));
3350 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3352 unsigned char osha1[20], nsha1[20];
3353 char *email_end, *message;
3354 unsigned long timestamp;
3355 int tz;
3357 /* old SP new SP name <email> SP time TAB msg LF */
3358 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3359 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3360 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3361 !(email_end = strchr(sb->buf + 82, '>')) ||
3362 email_end[1] != ' ' ||
3363 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3364 !message || message[0] != ' ' ||
3365 (message[1] != '+' && message[1] != '-') ||
3366 !isdigit(message[2]) || !isdigit(message[3]) ||
3367 !isdigit(message[4]) || !isdigit(message[5]))
3368 return 0; /* corrupt? */
3369 email_end[1] = '\0';
3370 tz = strtol(message + 1, NULL, 10);
3371 if (message[6] != '\t')
3372 message += 6;
3373 else
3374 message += 7;
3375 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3378 static char *find_beginning_of_line(char *bob, char *scan)
3380 while (bob < scan && *(--scan) != '\n')
3381 ; /* keep scanning backwards */
3383 * Return either beginning of the buffer, or LF at the end of
3384 * the previous line.
3386 return scan;
3389 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3391 struct strbuf sb = STRBUF_INIT;
3392 FILE *logfp;
3393 long pos;
3394 int ret = 0, at_tail = 1;
3396 logfp = fopen(git_path("logs/%s", refname), "r");
3397 if (!logfp)
3398 return -1;
3400 /* Jump to the end */
3401 if (fseek(logfp, 0, SEEK_END) < 0)
3402 return error("cannot seek back reflog for %s: %s",
3403 refname, strerror(errno));
3404 pos = ftell(logfp);
3405 while (!ret && 0 < pos) {
3406 int cnt;
3407 size_t nread;
3408 char buf[BUFSIZ];
3409 char *endp, *scanp;
3411 /* Fill next block from the end */
3412 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3413 if (fseek(logfp, pos - cnt, SEEK_SET))
3414 return error("cannot seek back reflog for %s: %s",
3415 refname, strerror(errno));
3416 nread = fread(buf, cnt, 1, logfp);
3417 if (nread != 1)
3418 return error("cannot read %d bytes from reflog for %s: %s",
3419 cnt, refname, strerror(errno));
3420 pos -= cnt;
3422 scanp = endp = buf + cnt;
3423 if (at_tail && scanp[-1] == '\n')
3424 /* Looking at the final LF at the end of the file */
3425 scanp--;
3426 at_tail = 0;
3428 while (buf < scanp) {
3430 * terminating LF of the previous line, or the beginning
3431 * of the buffer.
3433 char *bp;
3435 bp = find_beginning_of_line(buf, scanp);
3437 if (*bp == '\n') {
3439 * The newline is the end of the previous line,
3440 * so we know we have complete line starting
3441 * at (bp + 1). Prefix it onto any prior data
3442 * we collected for the line and process it.
3444 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3445 scanp = bp;
3446 endp = bp + 1;
3447 ret = show_one_reflog_ent(&sb, fn, cb_data);
3448 strbuf_reset(&sb);
3449 if (ret)
3450 break;
3451 } else if (!pos) {
3453 * We are at the start of the buffer, and the
3454 * start of the file; there is no previous
3455 * line, and we have everything for this one.
3456 * Process it, and we can end the loop.
3458 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3459 ret = show_one_reflog_ent(&sb, fn, cb_data);
3460 strbuf_reset(&sb);
3461 break;
3464 if (bp == buf) {
3466 * We are at the start of the buffer, and there
3467 * is more file to read backwards. Which means
3468 * we are in the middle of a line. Note that we
3469 * may get here even if *bp was a newline; that
3470 * just means we are at the exact end of the
3471 * previous line, rather than some spot in the
3472 * middle.
3474 * Save away what we have to be combined with
3475 * the data from the next read.
3477 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3478 break;
3483 if (!ret && sb.len)
3484 die("BUG: reverse reflog parser had leftover data");
3486 fclose(logfp);
3487 strbuf_release(&sb);
3488 return ret;
3491 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3493 FILE *logfp;
3494 struct strbuf sb = STRBUF_INIT;
3495 int ret = 0;
3497 logfp = fopen(git_path("logs/%s", refname), "r");
3498 if (!logfp)
3499 return -1;
3501 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3502 ret = show_one_reflog_ent(&sb, fn, cb_data);
3503 fclose(logfp);
3504 strbuf_release(&sb);
3505 return ret;
3508 * Call fn for each reflog in the namespace indicated by name. name
3509 * must be empty or end with '/'. Name will be used as a scratch
3510 * space, but its contents will be restored before return.
3512 static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3514 DIR *d = opendir(git_path("logs/%s", name->buf));
3515 int retval = 0;
3516 struct dirent *de;
3517 int oldlen = name->len;
3519 if (!d)
3520 return name->len ? errno : 0;
3522 while ((de = readdir(d)) != NULL) {
3523 struct stat st;
3525 if (de->d_name[0] == '.')
3526 continue;
3527 if (ends_with(de->d_name, ".lock"))
3528 continue;
3529 strbuf_addstr(name, de->d_name);
3530 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3531 ; /* silently ignore */
3532 } else {
3533 if (S_ISDIR(st.st_mode)) {
3534 strbuf_addch(name, '/');
3535 retval = do_for_each_reflog(name, fn, cb_data);
3536 } else {
3537 unsigned char sha1[20];
3538 if (read_ref_full(name->buf, 0, sha1, NULL))
3539 retval = error("bad ref for %s", name->buf);
3540 else
3541 retval = fn(name->buf, sha1, 0, cb_data);
3543 if (retval)
3544 break;
3546 strbuf_setlen(name, oldlen);
3548 closedir(d);
3549 return retval;
3552 int for_each_reflog(each_ref_fn fn, void *cb_data)
3554 int retval;
3555 struct strbuf name;
3556 strbuf_init(&name, PATH_MAX);
3557 retval = do_for_each_reflog(&name, fn, cb_data);
3558 strbuf_release(&name);
3559 return retval;
3563 * Information needed for a single ref update. Set new_sha1 to the new
3564 * value or to null_sha1 to delete the ref. To check the old value
3565 * while the ref is locked, set (flags & REF_HAVE_OLD) and set
3566 * old_sha1 to the old value, or to null_sha1 to ensure the ref does
3567 * not exist before update.
3569 struct ref_update {
3571 * If (flags & REF_HAVE_NEW), set the reference to this value:
3573 unsigned char new_sha1[20];
3575 * If (flags & REF_HAVE_OLD), check that the reference
3576 * previously had this value:
3578 unsigned char old_sha1[20];
3580 * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
3581 * REF_DELETING, and REF_ISPRUNING:
3583 unsigned int flags;
3584 struct ref_lock *lock;
3585 int type;
3586 char *msg;
3587 const char refname[FLEX_ARRAY];
3591 * Transaction states.
3592 * OPEN: The transaction is in a valid state and can accept new updates.
3593 * An OPEN transaction can be committed.
3594 * CLOSED: A closed transaction is no longer active and no other operations
3595 * than free can be used on it in this state.
3596 * A transaction can either become closed by successfully committing
3597 * an active transaction or if there is a failure while building
3598 * the transaction thus rendering it failed/inactive.
3600 enum ref_transaction_state {
3601 REF_TRANSACTION_OPEN = 0,
3602 REF_TRANSACTION_CLOSED = 1
3606 * Data structure for holding a reference transaction, which can
3607 * consist of checks and updates to multiple references, carried out
3608 * as atomically as possible. This structure is opaque to callers.
3610 struct ref_transaction {
3611 struct ref_update **updates;
3612 size_t alloc;
3613 size_t nr;
3614 enum ref_transaction_state state;
3617 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
3619 assert(err);
3621 return xcalloc(1, sizeof(struct ref_transaction));
3624 void ref_transaction_free(struct ref_transaction *transaction)
3626 int i;
3628 if (!transaction)
3629 return;
3631 for (i = 0; i < transaction->nr; i++) {
3632 free(transaction->updates[i]->msg);
3633 free(transaction->updates[i]);
3635 free(transaction->updates);
3636 free(transaction);
3639 static struct ref_update *add_update(struct ref_transaction *transaction,
3640 const char *refname)
3642 size_t len = strlen(refname);
3643 struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
3645 strcpy((char *)update->refname, refname);
3646 ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
3647 transaction->updates[transaction->nr++] = update;
3648 return update;
3651 int ref_transaction_update(struct ref_transaction *transaction,
3652 const char *refname,
3653 const unsigned char *new_sha1,
3654 const unsigned char *old_sha1,
3655 unsigned int flags, const char *msg,
3656 struct strbuf *err)
3658 struct ref_update *update;
3660 assert(err);
3662 if (transaction->state != REF_TRANSACTION_OPEN)
3663 die("BUG: update called for transaction that is not open");
3665 if (new_sha1 && !is_null_sha1(new_sha1) &&
3666 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
3667 strbuf_addf(err, "refusing to update ref with bad name %s",
3668 refname);
3669 return -1;
3672 update = add_update(transaction, refname);
3673 if (new_sha1) {
3674 hashcpy(update->new_sha1, new_sha1);
3675 flags |= REF_HAVE_NEW;
3677 if (old_sha1) {
3678 hashcpy(update->old_sha1, old_sha1);
3679 flags |= REF_HAVE_OLD;
3681 update->flags = flags;
3682 if (msg)
3683 update->msg = xstrdup(msg);
3684 return 0;
3687 int ref_transaction_create(struct ref_transaction *transaction,
3688 const char *refname,
3689 const unsigned char *new_sha1,
3690 unsigned int flags, const char *msg,
3691 struct strbuf *err)
3693 if (!new_sha1 || is_null_sha1(new_sha1))
3694 die("BUG: create called without valid new_sha1");
3695 return ref_transaction_update(transaction, refname, new_sha1,
3696 null_sha1, flags, msg, err);
3699 int ref_transaction_delete(struct ref_transaction *transaction,
3700 const char *refname,
3701 const unsigned char *old_sha1,
3702 unsigned int flags, const char *msg,
3703 struct strbuf *err)
3705 if (old_sha1 && is_null_sha1(old_sha1))
3706 die("BUG: delete called with old_sha1 set to zeros");
3707 return ref_transaction_update(transaction, refname,
3708 null_sha1, old_sha1,
3709 flags, msg, err);
3712 int ref_transaction_verify(struct ref_transaction *transaction,
3713 const char *refname,
3714 const unsigned char *old_sha1,
3715 unsigned int flags,
3716 struct strbuf *err)
3718 if (!old_sha1)
3719 die("BUG: verify called with old_sha1 set to NULL");
3720 return ref_transaction_update(transaction, refname,
3721 NULL, old_sha1,
3722 flags, NULL, err);
3725 int update_ref(const char *msg, const char *refname,
3726 const unsigned char *new_sha1, const unsigned char *old_sha1,
3727 unsigned int flags, enum action_on_err onerr)
3729 struct ref_transaction *t;
3730 struct strbuf err = STRBUF_INIT;
3732 t = ref_transaction_begin(&err);
3733 if (!t ||
3734 ref_transaction_update(t, refname, new_sha1, old_sha1,
3735 flags, msg, &err) ||
3736 ref_transaction_commit(t, &err)) {
3737 const char *str = "update_ref failed for ref '%s': %s";
3739 ref_transaction_free(t);
3740 switch (onerr) {
3741 case UPDATE_REFS_MSG_ON_ERR:
3742 error(str, refname, err.buf);
3743 break;
3744 case UPDATE_REFS_DIE_ON_ERR:
3745 die(str, refname, err.buf);
3746 break;
3747 case UPDATE_REFS_QUIET_ON_ERR:
3748 break;
3750 strbuf_release(&err);
3751 return 1;
3753 strbuf_release(&err);
3754 ref_transaction_free(t);
3755 return 0;
3758 static int ref_update_compare(const void *r1, const void *r2)
3760 const struct ref_update * const *u1 = r1;
3761 const struct ref_update * const *u2 = r2;
3762 return strcmp((*u1)->refname, (*u2)->refname);
3765 static int ref_update_reject_duplicates(struct ref_update **updates, int n,
3766 struct strbuf *err)
3768 int i;
3770 assert(err);
3772 for (i = 1; i < n; i++)
3773 if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
3774 strbuf_addf(err,
3775 "Multiple updates for ref '%s' not allowed.",
3776 updates[i]->refname);
3777 return 1;
3779 return 0;
3782 int ref_transaction_commit(struct ref_transaction *transaction,
3783 struct strbuf *err)
3785 int ret = 0, i;
3786 int n = transaction->nr;
3787 struct ref_update **updates = transaction->updates;
3788 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3789 struct string_list_item *ref_to_delete;
3791 assert(err);
3793 if (transaction->state != REF_TRANSACTION_OPEN)
3794 die("BUG: commit called for transaction that is not open");
3796 if (!n) {
3797 transaction->state = REF_TRANSACTION_CLOSED;
3798 return 0;
3801 /* Copy, sort, and reject duplicate refs */
3802 qsort(updates, n, sizeof(*updates), ref_update_compare);
3803 if (ref_update_reject_duplicates(updates, n, err)) {
3804 ret = TRANSACTION_GENERIC_ERROR;
3805 goto cleanup;
3808 /* Acquire all locks while verifying old values */
3809 for (i = 0; i < n; i++) {
3810 struct ref_update *update = updates[i];
3811 unsigned int flags = update->flags;
3813 if ((flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
3814 flags |= REF_DELETING;
3815 update->lock = lock_ref_sha1_basic(
3816 update->refname,
3817 ((update->flags & REF_HAVE_OLD) ?
3818 update->old_sha1 : NULL),
3819 NULL,
3820 flags,
3821 &update->type);
3822 if (!update->lock) {
3823 ret = (errno == ENOTDIR)
3824 ? TRANSACTION_NAME_CONFLICT
3825 : TRANSACTION_GENERIC_ERROR;
3826 strbuf_addf(err, "Cannot lock the ref '%s'.",
3827 update->refname);
3828 goto cleanup;
3832 /* Perform updates first so live commits remain referenced */
3833 for (i = 0; i < n; i++) {
3834 struct ref_update *update = updates[i];
3835 int flags = update->flags;
3837 if ((flags & REF_HAVE_NEW) && !is_null_sha1(update->new_sha1)) {
3838 int overwriting_symref = ((update->type & REF_ISSYMREF) &&
3839 (update->flags & REF_NODEREF));
3841 if (!overwriting_symref
3842 && !hashcmp(update->lock->old_sha1, update->new_sha1)) {
3844 * The reference already has the desired
3845 * value, so we don't need to write it.
3847 unlock_ref(update->lock);
3848 update->lock = NULL;
3849 } else if (write_ref_sha1(update->lock, update->new_sha1,
3850 update->msg)) {
3851 update->lock = NULL; /* freed by write_ref_sha1 */
3852 strbuf_addf(err, "Cannot update the ref '%s'.",
3853 update->refname);
3854 ret = TRANSACTION_GENERIC_ERROR;
3855 goto cleanup;
3856 } else {
3857 /* freed by write_ref_sha1(): */
3858 update->lock = NULL;
3863 /* Perform deletes now that updates are safely completed */
3864 for (i = 0; i < n; i++) {
3865 struct ref_update *update = updates[i];
3866 int flags = update->flags;
3868 if ((flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1)) {
3869 if (delete_ref_loose(update->lock, update->type, err)) {
3870 ret = TRANSACTION_GENERIC_ERROR;
3871 goto cleanup;
3874 if (!(flags & REF_ISPRUNING))
3875 string_list_append(&refs_to_delete,
3876 update->lock->ref_name);
3880 if (repack_without_refs(&refs_to_delete, err)) {
3881 ret = TRANSACTION_GENERIC_ERROR;
3882 goto cleanup;
3884 for_each_string_list_item(ref_to_delete, &refs_to_delete)
3885 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
3886 clear_loose_ref_cache(&ref_cache);
3888 cleanup:
3889 transaction->state = REF_TRANSACTION_CLOSED;
3891 for (i = 0; i < n; i++)
3892 if (updates[i]->lock)
3893 unlock_ref(updates[i]->lock);
3894 string_list_clear(&refs_to_delete, 0);
3895 return ret;
3898 char *shorten_unambiguous_ref(const char *refname, int strict)
3900 int i;
3901 static char **scanf_fmts;
3902 static int nr_rules;
3903 char *short_name;
3905 if (!nr_rules) {
3907 * Pre-generate scanf formats from ref_rev_parse_rules[].
3908 * Generate a format suitable for scanf from a
3909 * ref_rev_parse_rules rule by interpolating "%s" at the
3910 * location of the "%.*s".
3912 size_t total_len = 0;
3913 size_t offset = 0;
3915 /* the rule list is NULL terminated, count them first */
3916 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
3917 /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
3918 total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
3920 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
3922 offset = 0;
3923 for (i = 0; i < nr_rules; i++) {
3924 assert(offset < total_len);
3925 scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
3926 offset += snprintf(scanf_fmts[i], total_len - offset,
3927 ref_rev_parse_rules[i], 2, "%s") + 1;
3931 /* bail out if there are no rules */
3932 if (!nr_rules)
3933 return xstrdup(refname);
3935 /* buffer for scanf result, at most refname must fit */
3936 short_name = xstrdup(refname);
3938 /* skip first rule, it will always match */
3939 for (i = nr_rules - 1; i > 0 ; --i) {
3940 int j;
3941 int rules_to_fail = i;
3942 int short_name_len;
3944 if (1 != sscanf(refname, scanf_fmts[i], short_name))
3945 continue;
3947 short_name_len = strlen(short_name);
3950 * in strict mode, all (except the matched one) rules
3951 * must fail to resolve to a valid non-ambiguous ref
3953 if (strict)
3954 rules_to_fail = nr_rules;
3957 * check if the short name resolves to a valid ref,
3958 * but use only rules prior to the matched one
3960 for (j = 0; j < rules_to_fail; j++) {
3961 const char *rule = ref_rev_parse_rules[j];
3962 char refname[PATH_MAX];
3964 /* skip matched rule */
3965 if (i == j)
3966 continue;
3969 * the short name is ambiguous, if it resolves
3970 * (with this previous rule) to a valid ref
3971 * read_ref() returns 0 on success
3973 mksnpath(refname, sizeof(refname),
3974 rule, short_name_len, short_name);
3975 if (ref_exists(refname))
3976 break;
3980 * short name is non-ambiguous if all previous rules
3981 * haven't resolved to a valid ref
3983 if (j == rules_to_fail)
3984 return short_name;
3987 free(short_name);
3988 return xstrdup(refname);
3991 static struct string_list *hide_refs;
3993 int parse_hide_refs_config(const char *var, const char *value, const char *section)
3995 if (!strcmp("transfer.hiderefs", var) ||
3996 /* NEEDSWORK: use parse_config_key() once both are merged */
3997 (starts_with(var, section) && var[strlen(section)] == '.' &&
3998 !strcmp(var + strlen(section), ".hiderefs"))) {
3999 char *ref;
4000 int len;
4002 if (!value)
4003 return config_error_nonbool(var);
4004 ref = xstrdup(value);
4005 len = strlen(ref);
4006 while (len && ref[len - 1] == '/')
4007 ref[--len] = '\0';
4008 if (!hide_refs) {
4009 hide_refs = xcalloc(1, sizeof(*hide_refs));
4010 hide_refs->strdup_strings = 1;
4012 string_list_append(hide_refs, ref);
4014 return 0;
4017 int ref_is_hidden(const char *refname)
4019 struct string_list_item *item;
4021 if (!hide_refs)
4022 return 0;
4023 for_each_string_list_item(item, hide_refs) {
4024 int len;
4025 if (!starts_with(refname, item->string))
4026 continue;
4027 len = strlen(item->string);
4028 if (!refname[len] || refname[len] == '/')
4029 return 1;
4031 return 0;
4034 struct expire_reflog_cb {
4035 unsigned int flags;
4036 reflog_expiry_should_prune_fn *should_prune_fn;
4037 void *policy_cb;
4038 FILE *newlog;
4039 unsigned char last_kept_sha1[20];
4042 static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
4043 const char *email, unsigned long timestamp, int tz,
4044 const char *message, void *cb_data)
4046 struct expire_reflog_cb *cb = cb_data;
4047 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
4049 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
4050 osha1 = cb->last_kept_sha1;
4052 if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,
4053 message, policy_cb)) {
4054 if (!cb->newlog)
4055 printf("would prune %s", message);
4056 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
4057 printf("prune %s", message);
4058 } else {
4059 if (cb->newlog) {
4060 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
4061 sha1_to_hex(osha1), sha1_to_hex(nsha1),
4062 email, timestamp, tz, message);
4063 hashcpy(cb->last_kept_sha1, nsha1);
4065 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
4066 printf("keep %s", message);
4068 return 0;
4071 int reflog_expire(const char *refname, const unsigned char *sha1,
4072 unsigned int flags,
4073 reflog_expiry_prepare_fn prepare_fn,
4074 reflog_expiry_should_prune_fn should_prune_fn,
4075 reflog_expiry_cleanup_fn cleanup_fn,
4076 void *policy_cb_data)
4078 static struct lock_file reflog_lock;
4079 struct expire_reflog_cb cb;
4080 struct ref_lock *lock;
4081 char *log_file;
4082 int status = 0;
4083 int type;
4085 memset(&cb, 0, sizeof(cb));
4086 cb.flags = flags;
4087 cb.policy_cb = policy_cb_data;
4088 cb.should_prune_fn = should_prune_fn;
4091 * The reflog file is locked by holding the lock on the
4092 * reference itself, plus we might need to update the
4093 * reference if --updateref was specified:
4095 lock = lock_ref_sha1_basic(refname, sha1, NULL, 0, &type);
4096 if (!lock)
4097 return error("cannot lock ref '%s'", refname);
4098 if (!reflog_exists(refname)) {
4099 unlock_ref(lock);
4100 return 0;
4103 log_file = git_pathdup("logs/%s", refname);
4104 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
4106 * Even though holding $GIT_DIR/logs/$reflog.lock has
4107 * no locking implications, we use the lock_file
4108 * machinery here anyway because it does a lot of the
4109 * work we need, including cleaning up if the program
4110 * exits unexpectedly.
4112 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
4113 struct strbuf err = STRBUF_INIT;
4114 unable_to_lock_message(log_file, errno, &err);
4115 error("%s", err.buf);
4116 strbuf_release(&err);
4117 goto failure;
4119 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
4120 if (!cb.newlog) {
4121 error("cannot fdopen %s (%s)",
4122 reflog_lock.filename.buf, strerror(errno));
4123 goto failure;
4127 (*prepare_fn)(refname, sha1, cb.policy_cb);
4128 for_each_reflog_ent(refname, expire_reflog_ent, &cb);
4129 (*cleanup_fn)(cb.policy_cb);
4131 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
4133 * It doesn't make sense to adjust a reference pointed
4134 * to by a symbolic ref based on expiring entries in
4135 * the symbolic reference's reflog. Nor can we update
4136 * a reference if there are no remaining reflog
4137 * entries.
4139 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
4140 !(type & REF_ISSYMREF) &&
4141 !is_null_sha1(cb.last_kept_sha1);
4143 if (close_lock_file(&reflog_lock)) {
4144 status |= error("couldn't write %s: %s", log_file,
4145 strerror(errno));
4146 } else if (update &&
4147 (write_in_full(lock->lock_fd,
4148 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
4149 write_str_in_full(lock->lock_fd, "\n") != 1 ||
4150 close_ref(lock) < 0)) {
4151 status |= error("couldn't write %s",
4152 lock->lk->filename.buf);
4153 rollback_lock_file(&reflog_lock);
4154 } else if (commit_lock_file(&reflog_lock)) {
4155 status |= error("unable to commit reflog '%s' (%s)",
4156 log_file, strerror(errno));
4157 } else if (update && commit_ref(lock)) {
4158 status |= error("couldn't set %s", lock->ref_name);
4161 free(log_file);
4162 unlock_ref(lock);
4163 return status;
4165 failure:
4166 rollback_lock_file(&reflog_lock);
4167 free(log_file);
4168 unlock_ref(lock);
4169 return -1;