l10n: zh_CN: Add translations for Git glossary
[git/git-svn.git] / refs.c
blob7ac05cf21a25802f8e16d45ef75e37b7de2cda8a
1 #include "cache.h"
2 #include "lockfile.h"
3 #include "refs.h"
4 #include "object.h"
5 #include "tag.h"
6 #include "dir.h"
7 #include "string-list.h"
9 struct ref_lock {
10 char *ref_name;
11 char *orig_ref_name;
12 struct lock_file *lk;
13 struct object_id old_oid;
17 * How to handle various characters in refnames:
18 * 0: An acceptable character for refs
19 * 1: End-of-component
20 * 2: ., look for a preceding . to reject .. in refs
21 * 3: {, look for a preceding @ to reject @{ in refs
22 * 4: A bad character: ASCII control characters, "~", "^", ":" or SP
24 static unsigned char refname_disposition[256] = {
25 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
26 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
27 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 2, 1,
28 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
29 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
30 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
31 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
32 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
36 * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
37 * refs (i.e., because the reference is about to be deleted anyway).
39 #define REF_DELETING 0x02
42 * Used as a flag in ref_update::flags when a loose ref is being
43 * pruned.
45 #define REF_ISPRUNING 0x04
48 * Used as a flag in ref_update::flags when the reference should be
49 * updated to new_sha1.
51 #define REF_HAVE_NEW 0x08
54 * Used as a flag in ref_update::flags when old_sha1 should be
55 * checked.
57 #define REF_HAVE_OLD 0x10
60 * Used as a flag in ref_update::flags when the lockfile needs to be
61 * committed.
63 #define REF_NEEDS_COMMIT 0x20
66 * Try to read one refname component from the front of refname.
67 * Return the length of the component found, or -1 if the component is
68 * not legal. It is legal if it is something reasonable to have under
69 * ".git/refs/"; We do not like it if:
71 * - any path component of it begins with ".", or
72 * - it has double dots "..", or
73 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
74 * - it ends with a "/".
75 * - it ends with ".lock"
76 * - it contains a "\" (backslash)
78 static int check_refname_component(const char *refname, int flags)
80 const char *cp;
81 char last = '\0';
83 for (cp = refname; ; cp++) {
84 int ch = *cp & 255;
85 unsigned char disp = refname_disposition[ch];
86 switch (disp) {
87 case 1:
88 goto out;
89 case 2:
90 if (last == '.')
91 return -1; /* Refname contains "..". */
92 break;
93 case 3:
94 if (last == '@')
95 return -1; /* Refname contains "@{". */
96 break;
97 case 4:
98 return -1;
100 last = ch;
102 out:
103 if (cp == refname)
104 return 0; /* Component has zero length. */
105 if (refname[0] == '.')
106 return -1; /* Component starts with '.'. */
107 if (cp - refname >= LOCK_SUFFIX_LEN &&
108 !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
109 return -1; /* Refname ends with ".lock". */
110 return cp - refname;
113 int check_refname_format(const char *refname, int flags)
115 int component_len, component_count = 0;
117 if (!strcmp(refname, "@"))
118 /* Refname is a single character '@'. */
119 return -1;
121 while (1) {
122 /* We are at the start of a path component. */
123 component_len = check_refname_component(refname, flags);
124 if (component_len <= 0) {
125 if ((flags & REFNAME_REFSPEC_PATTERN) &&
126 refname[0] == '*' &&
127 (refname[1] == '\0' || refname[1] == '/')) {
128 /* Accept one wildcard as a full refname component. */
129 flags &= ~REFNAME_REFSPEC_PATTERN;
130 component_len = 1;
131 } else {
132 return -1;
135 component_count++;
136 if (refname[component_len] == '\0')
137 break;
138 /* Skip to next component. */
139 refname += component_len + 1;
142 if (refname[component_len - 1] == '.')
143 return -1; /* Refname ends with '.'. */
144 if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
145 return -1; /* Refname has only one component. */
146 return 0;
149 struct ref_entry;
152 * Information used (along with the information in ref_entry) to
153 * describe a single cached reference. This data structure only
154 * occurs embedded in a union in struct ref_entry, and only when
155 * (ref_entry->flag & REF_DIR) is zero.
157 struct ref_value {
159 * The name of the object to which this reference resolves
160 * (which may be a tag object). If REF_ISBROKEN, this is
161 * null. If REF_ISSYMREF, then this is the name of the object
162 * referred to by the last reference in the symlink chain.
164 struct object_id oid;
167 * If REF_KNOWS_PEELED, then this field holds the peeled value
168 * of this reference, or null if the reference is known not to
169 * be peelable. See the documentation for peel_ref() for an
170 * exact definition of "peelable".
172 struct object_id peeled;
175 struct ref_cache;
178 * Information used (along with the information in ref_entry) to
179 * describe a level in the hierarchy of references. This data
180 * structure only occurs embedded in a union in struct ref_entry, and
181 * only when (ref_entry.flag & REF_DIR) is set. In that case,
182 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
183 * in the directory have already been read:
185 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
186 * or packed references, already read.
188 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
189 * references that hasn't been read yet (nor has any of its
190 * subdirectories).
192 * Entries within a directory are stored within a growable array of
193 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
194 * sorted are sorted by their component name in strcmp() order and the
195 * remaining entries are unsorted.
197 * Loose references are read lazily, one directory at a time. When a
198 * directory of loose references is read, then all of the references
199 * in that directory are stored, and REF_INCOMPLETE stubs are created
200 * for any subdirectories, but the subdirectories themselves are not
201 * read. The reading is triggered by get_ref_dir().
203 struct ref_dir {
204 int nr, alloc;
207 * Entries with index 0 <= i < sorted are sorted by name. New
208 * entries are appended to the list unsorted, and are sorted
209 * only when required; thus we avoid the need to sort the list
210 * after the addition of every reference.
212 int sorted;
214 /* A pointer to the ref_cache that contains this ref_dir. */
215 struct ref_cache *ref_cache;
217 struct ref_entry **entries;
221 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
222 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
223 * public values; see refs.h.
227 * The field ref_entry->u.value.peeled of this value entry contains
228 * the correct peeled value for the reference, which might be
229 * null_sha1 if the reference is not a tag or if it is broken.
231 #define REF_KNOWS_PEELED 0x10
233 /* ref_entry represents a directory of references */
234 #define REF_DIR 0x20
237 * Entry has not yet been read from disk (used only for REF_DIR
238 * entries representing loose references)
240 #define REF_INCOMPLETE 0x40
243 * A ref_entry represents either a reference or a "subdirectory" of
244 * references.
246 * Each directory in the reference namespace is represented by a
247 * ref_entry with (flags & REF_DIR) set and containing a subdir member
248 * that holds the entries in that directory that have been read so
249 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
250 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
251 * used for loose reference directories.
253 * References are represented by a ref_entry with (flags & REF_DIR)
254 * unset and a value member that describes the reference's value. The
255 * flag member is at the ref_entry level, but it is also needed to
256 * interpret the contents of the value field (in other words, a
257 * ref_value object is not very much use without the enclosing
258 * ref_entry).
260 * Reference names cannot end with slash and directories' names are
261 * always stored with a trailing slash (except for the top-level
262 * directory, which is always denoted by ""). This has two nice
263 * consequences: (1) when the entries in each subdir are sorted
264 * lexicographically by name (as they usually are), the references in
265 * a whole tree can be generated in lexicographic order by traversing
266 * the tree in left-to-right, depth-first order; (2) the names of
267 * references and subdirectories cannot conflict, and therefore the
268 * presence of an empty subdirectory does not block the creation of a
269 * similarly-named reference. (The fact that reference names with the
270 * same leading components can conflict *with each other* is a
271 * separate issue that is regulated by verify_refname_available().)
273 * Please note that the name field contains the fully-qualified
274 * reference (or subdirectory) name. Space could be saved by only
275 * storing the relative names. But that would require the full names
276 * to be generated on the fly when iterating in do_for_each_ref(), and
277 * would break callback functions, who have always been able to assume
278 * that the name strings that they are passed will not be freed during
279 * the iteration.
281 struct ref_entry {
282 unsigned char flag; /* ISSYMREF? ISPACKED? */
283 union {
284 struct ref_value value; /* if not (flags&REF_DIR) */
285 struct ref_dir subdir; /* if (flags&REF_DIR) */
286 } u;
288 * The full name of the reference (e.g., "refs/heads/master")
289 * or the full name of the directory with a trailing slash
290 * (e.g., "refs/heads/"):
292 char name[FLEX_ARRAY];
295 static void read_loose_refs(const char *dirname, struct ref_dir *dir);
297 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
299 struct ref_dir *dir;
300 assert(entry->flag & REF_DIR);
301 dir = &entry->u.subdir;
302 if (entry->flag & REF_INCOMPLETE) {
303 read_loose_refs(entry->name, dir);
304 entry->flag &= ~REF_INCOMPLETE;
306 return dir;
310 * Check if a refname is safe.
311 * For refs that start with "refs/" we consider it safe as long they do
312 * not try to resolve to outside of refs/.
314 * For all other refs we only consider them safe iff they only contain
315 * upper case characters and '_' (like "HEAD" AND "MERGE_HEAD", and not like
316 * "config").
318 static int refname_is_safe(const char *refname)
320 if (starts_with(refname, "refs/")) {
321 char *buf;
322 int result;
324 buf = xmalloc(strlen(refname) + 1);
326 * Does the refname try to escape refs/?
327 * For example: refs/foo/../bar is safe but refs/foo/../../bar
328 * is not.
330 result = !normalize_path_copy(buf, refname + strlen("refs/"));
331 free(buf);
332 return result;
334 while (*refname) {
335 if (!isupper(*refname) && *refname != '_')
336 return 0;
337 refname++;
339 return 1;
342 static struct ref_entry *create_ref_entry(const char *refname,
343 const unsigned char *sha1, int flag,
344 int check_name)
346 int len;
347 struct ref_entry *ref;
349 if (check_name &&
350 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
351 die("Reference has invalid format: '%s'", refname);
352 len = strlen(refname) + 1;
353 ref = xmalloc(sizeof(struct ref_entry) + len);
354 hashcpy(ref->u.value.oid.hash, sha1);
355 oidclr(&ref->u.value.peeled);
356 memcpy(ref->name, refname, len);
357 ref->flag = flag;
358 return ref;
361 static void clear_ref_dir(struct ref_dir *dir);
363 static void free_ref_entry(struct ref_entry *entry)
365 if (entry->flag & REF_DIR) {
367 * Do not use get_ref_dir() here, as that might
368 * trigger the reading of loose refs.
370 clear_ref_dir(&entry->u.subdir);
372 free(entry);
376 * Add a ref_entry to the end of dir (unsorted). Entry is always
377 * stored directly in dir; no recursion into subdirectories is
378 * done.
380 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
382 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
383 dir->entries[dir->nr++] = entry;
384 /* optimize for the case that entries are added in order */
385 if (dir->nr == 1 ||
386 (dir->nr == dir->sorted + 1 &&
387 strcmp(dir->entries[dir->nr - 2]->name,
388 dir->entries[dir->nr - 1]->name) < 0))
389 dir->sorted = dir->nr;
393 * Clear and free all entries in dir, recursively.
395 static void clear_ref_dir(struct ref_dir *dir)
397 int i;
398 for (i = 0; i < dir->nr; i++)
399 free_ref_entry(dir->entries[i]);
400 free(dir->entries);
401 dir->sorted = dir->nr = dir->alloc = 0;
402 dir->entries = NULL;
406 * Create a struct ref_entry object for the specified dirname.
407 * dirname is the name of the directory with a trailing slash (e.g.,
408 * "refs/heads/") or "" for the top-level directory.
410 static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
411 const char *dirname, size_t len,
412 int incomplete)
414 struct ref_entry *direntry;
415 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
416 memcpy(direntry->name, dirname, len);
417 direntry->name[len] = '\0';
418 direntry->u.subdir.ref_cache = ref_cache;
419 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
420 return direntry;
423 static int ref_entry_cmp(const void *a, const void *b)
425 struct ref_entry *one = *(struct ref_entry **)a;
426 struct ref_entry *two = *(struct ref_entry **)b;
427 return strcmp(one->name, two->name);
430 static void sort_ref_dir(struct ref_dir *dir);
432 struct string_slice {
433 size_t len;
434 const char *str;
437 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
439 const struct string_slice *key = key_;
440 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
441 int cmp = strncmp(key->str, ent->name, key->len);
442 if (cmp)
443 return cmp;
444 return '\0' - (unsigned char)ent->name[key->len];
448 * Return the index of the entry with the given refname from the
449 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
450 * no such entry is found. dir must already be complete.
452 static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
454 struct ref_entry **r;
455 struct string_slice key;
457 if (refname == NULL || !dir->nr)
458 return -1;
460 sort_ref_dir(dir);
461 key.len = len;
462 key.str = refname;
463 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
464 ref_entry_cmp_sslice);
466 if (r == NULL)
467 return -1;
469 return r - dir->entries;
473 * Search for a directory entry directly within dir (without
474 * recursing). Sort dir if necessary. subdirname must be a directory
475 * name (i.e., end in '/'). If mkdir is set, then create the
476 * directory if it is missing; otherwise, return NULL if the desired
477 * directory cannot be found. dir must already be complete.
479 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
480 const char *subdirname, size_t len,
481 int mkdir)
483 int entry_index = search_ref_dir(dir, subdirname, len);
484 struct ref_entry *entry;
485 if (entry_index == -1) {
486 if (!mkdir)
487 return NULL;
489 * Since dir is complete, the absence of a subdir
490 * means that the subdir really doesn't exist;
491 * therefore, create an empty record for it but mark
492 * the record complete.
494 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
495 add_entry_to_dir(dir, entry);
496 } else {
497 entry = dir->entries[entry_index];
499 return get_ref_dir(entry);
503 * If refname is a reference name, find the ref_dir within the dir
504 * tree that should hold refname. If refname is a directory name
505 * (i.e., ends in '/'), then return that ref_dir itself. dir must
506 * represent the top-level directory and must already be complete.
507 * Sort ref_dirs and recurse into subdirectories as necessary. If
508 * mkdir is set, then create any missing directories; otherwise,
509 * return NULL if the desired directory cannot be found.
511 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
512 const char *refname, int mkdir)
514 const char *slash;
515 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
516 size_t dirnamelen = slash - refname + 1;
517 struct ref_dir *subdir;
518 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
519 if (!subdir) {
520 dir = NULL;
521 break;
523 dir = subdir;
526 return dir;
530 * Find the value entry with the given name in dir, sorting ref_dirs
531 * and recursing into subdirectories as necessary. If the name is not
532 * found or it corresponds to a directory entry, return NULL.
534 static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
536 int entry_index;
537 struct ref_entry *entry;
538 dir = find_containing_dir(dir, refname, 0);
539 if (!dir)
540 return NULL;
541 entry_index = search_ref_dir(dir, refname, strlen(refname));
542 if (entry_index == -1)
543 return NULL;
544 entry = dir->entries[entry_index];
545 return (entry->flag & REF_DIR) ? NULL : entry;
549 * Remove the entry with the given name from dir, recursing into
550 * subdirectories as necessary. If refname is the name of a directory
551 * (i.e., ends with '/'), then remove the directory and its contents.
552 * If the removal was successful, return the number of entries
553 * remaining in the directory entry that contained the deleted entry.
554 * If the name was not found, return -1. Please note that this
555 * function only deletes the entry from the cache; it does not delete
556 * it from the filesystem or ensure that other cache entries (which
557 * might be symbolic references to the removed entry) are updated.
558 * Nor does it remove any containing dir entries that might be made
559 * empty by the removal. dir must represent the top-level directory
560 * and must already be complete.
562 static int remove_entry(struct ref_dir *dir, const char *refname)
564 int refname_len = strlen(refname);
565 int entry_index;
566 struct ref_entry *entry;
567 int is_dir = refname[refname_len - 1] == '/';
568 if (is_dir) {
570 * refname represents a reference directory. Remove
571 * the trailing slash; otherwise we will get the
572 * directory *representing* refname rather than the
573 * one *containing* it.
575 char *dirname = xmemdupz(refname, refname_len - 1);
576 dir = find_containing_dir(dir, dirname, 0);
577 free(dirname);
578 } else {
579 dir = find_containing_dir(dir, refname, 0);
581 if (!dir)
582 return -1;
583 entry_index = search_ref_dir(dir, refname, refname_len);
584 if (entry_index == -1)
585 return -1;
586 entry = dir->entries[entry_index];
588 memmove(&dir->entries[entry_index],
589 &dir->entries[entry_index + 1],
590 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
592 dir->nr--;
593 if (dir->sorted > entry_index)
594 dir->sorted--;
595 free_ref_entry(entry);
596 return dir->nr;
600 * Add a ref_entry to the ref_dir (unsorted), recursing into
601 * subdirectories as necessary. dir must represent the top-level
602 * directory. Return 0 on success.
604 static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
606 dir = find_containing_dir(dir, ref->name, 1);
607 if (!dir)
608 return -1;
609 add_entry_to_dir(dir, ref);
610 return 0;
614 * Emit a warning and return true iff ref1 and ref2 have the same name
615 * and the same sha1. Die if they have the same name but different
616 * sha1s.
618 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
620 if (strcmp(ref1->name, ref2->name))
621 return 0;
623 /* Duplicate name; make sure that they don't conflict: */
625 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
626 /* This is impossible by construction */
627 die("Reference directory conflict: %s", ref1->name);
629 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
630 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
632 warning("Duplicated ref: %s", ref1->name);
633 return 1;
637 * Sort the entries in dir non-recursively (if they are not already
638 * sorted) and remove any duplicate entries.
640 static void sort_ref_dir(struct ref_dir *dir)
642 int i, j;
643 struct ref_entry *last = NULL;
646 * This check also prevents passing a zero-length array to qsort(),
647 * which is a problem on some platforms.
649 if (dir->sorted == dir->nr)
650 return;
652 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
654 /* Remove any duplicates: */
655 for (i = 0, j = 0; j < dir->nr; j++) {
656 struct ref_entry *entry = dir->entries[j];
657 if (last && is_dup_ref(last, entry))
658 free_ref_entry(entry);
659 else
660 last = dir->entries[i++] = entry;
662 dir->sorted = dir->nr = i;
665 /* Include broken references in a do_for_each_ref*() iteration: */
666 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
669 * Return true iff the reference described by entry can be resolved to
670 * an object in the database. Emit a warning if the referred-to
671 * object does not exist.
673 static int ref_resolves_to_object(struct ref_entry *entry)
675 if (entry->flag & REF_ISBROKEN)
676 return 0;
677 if (!has_sha1_file(entry->u.value.oid.hash)) {
678 error("%s does not point to a valid object!", entry->name);
679 return 0;
681 return 1;
685 * current_ref is a performance hack: when iterating over references
686 * using the for_each_ref*() functions, current_ref is set to the
687 * current reference's entry before calling the callback function. If
688 * the callback function calls peel_ref(), then peel_ref() first
689 * checks whether the reference to be peeled is the current reference
690 * (it usually is) and if so, returns that reference's peeled version
691 * if it is available. This avoids a refname lookup in a common case.
693 static struct ref_entry *current_ref;
695 typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
697 struct ref_entry_cb {
698 const char *base;
699 int trim;
700 int flags;
701 each_ref_fn *fn;
702 void *cb_data;
706 * Handle one reference in a do_for_each_ref*()-style iteration,
707 * calling an each_ref_fn for each entry.
709 static int do_one_ref(struct ref_entry *entry, void *cb_data)
711 struct ref_entry_cb *data = cb_data;
712 struct ref_entry *old_current_ref;
713 int retval;
715 if (!starts_with(entry->name, data->base))
716 return 0;
718 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
719 !ref_resolves_to_object(entry))
720 return 0;
722 /* Store the old value, in case this is a recursive call: */
723 old_current_ref = current_ref;
724 current_ref = entry;
725 retval = data->fn(entry->name + data->trim, &entry->u.value.oid,
726 entry->flag, data->cb_data);
727 current_ref = old_current_ref;
728 return retval;
732 * Call fn for each reference in dir that has index in the range
733 * offset <= index < dir->nr. Recurse into subdirectories that are in
734 * that index range, sorting them before iterating. This function
735 * does not sort dir itself; it should be sorted beforehand. fn is
736 * called for all references, including broken ones.
738 static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
739 each_ref_entry_fn fn, void *cb_data)
741 int i;
742 assert(dir->sorted == dir->nr);
743 for (i = offset; i < dir->nr; i++) {
744 struct ref_entry *entry = dir->entries[i];
745 int retval;
746 if (entry->flag & REF_DIR) {
747 struct ref_dir *subdir = get_ref_dir(entry);
748 sort_ref_dir(subdir);
749 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
750 } else {
751 retval = fn(entry, cb_data);
753 if (retval)
754 return retval;
756 return 0;
760 * Call fn for each reference in the union of dir1 and dir2, in order
761 * by refname. Recurse into subdirectories. If a value entry appears
762 * in both dir1 and dir2, then only process the version that is in
763 * dir2. The input dirs must already be sorted, but subdirs will be
764 * sorted as needed. fn is called for all references, including
765 * broken ones.
767 static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
768 struct ref_dir *dir2,
769 each_ref_entry_fn fn, void *cb_data)
771 int retval;
772 int i1 = 0, i2 = 0;
774 assert(dir1->sorted == dir1->nr);
775 assert(dir2->sorted == dir2->nr);
776 while (1) {
777 struct ref_entry *e1, *e2;
778 int cmp;
779 if (i1 == dir1->nr) {
780 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
782 if (i2 == dir2->nr) {
783 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
785 e1 = dir1->entries[i1];
786 e2 = dir2->entries[i2];
787 cmp = strcmp(e1->name, e2->name);
788 if (cmp == 0) {
789 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
790 /* Both are directories; descend them in parallel. */
791 struct ref_dir *subdir1 = get_ref_dir(e1);
792 struct ref_dir *subdir2 = get_ref_dir(e2);
793 sort_ref_dir(subdir1);
794 sort_ref_dir(subdir2);
795 retval = do_for_each_entry_in_dirs(
796 subdir1, subdir2, fn, cb_data);
797 i1++;
798 i2++;
799 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
800 /* Both are references; ignore the one from dir1. */
801 retval = fn(e2, cb_data);
802 i1++;
803 i2++;
804 } else {
805 die("conflict between reference and directory: %s",
806 e1->name);
808 } else {
809 struct ref_entry *e;
810 if (cmp < 0) {
811 e = e1;
812 i1++;
813 } else {
814 e = e2;
815 i2++;
817 if (e->flag & REF_DIR) {
818 struct ref_dir *subdir = get_ref_dir(e);
819 sort_ref_dir(subdir);
820 retval = do_for_each_entry_in_dir(
821 subdir, 0, fn, cb_data);
822 } else {
823 retval = fn(e, cb_data);
826 if (retval)
827 return retval;
832 * Load all of the refs from the dir into our in-memory cache. The hard work
833 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
834 * through all of the sub-directories. We do not even need to care about
835 * sorting, as traversal order does not matter to us.
837 static void prime_ref_dir(struct ref_dir *dir)
839 int i;
840 for (i = 0; i < dir->nr; i++) {
841 struct ref_entry *entry = dir->entries[i];
842 if (entry->flag & REF_DIR)
843 prime_ref_dir(get_ref_dir(entry));
847 struct nonmatching_ref_data {
848 const struct string_list *skip;
849 const char *conflicting_refname;
852 static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
854 struct nonmatching_ref_data *data = vdata;
856 if (data->skip && string_list_has_string(data->skip, entry->name))
857 return 0;
859 data->conflicting_refname = entry->name;
860 return 1;
864 * Return 0 if a reference named refname could be created without
865 * conflicting with the name of an existing reference in dir.
866 * Otherwise, return a negative value and write an explanation to err.
867 * If extras is non-NULL, it is a list of additional refnames with
868 * which refname is not allowed to conflict. If skip is non-NULL,
869 * ignore potential conflicts with refs in skip (e.g., because they
870 * are scheduled for deletion in the same operation). Behavior is
871 * undefined if the same name is listed in both extras and skip.
873 * Two reference names conflict if one of them exactly matches the
874 * leading components of the other; e.g., "refs/foo/bar" conflicts
875 * with both "refs/foo" and with "refs/foo/bar/baz" but not with
876 * "refs/foo/bar" or "refs/foo/barbados".
878 * extras and skip must be sorted.
880 static int verify_refname_available(const char *refname,
881 const struct string_list *extras,
882 const struct string_list *skip,
883 struct ref_dir *dir,
884 struct strbuf *err)
886 const char *slash;
887 int pos;
888 struct strbuf dirname = STRBUF_INIT;
889 int ret = -1;
892 * For the sake of comments in this function, suppose that
893 * refname is "refs/foo/bar".
896 assert(err);
898 strbuf_grow(&dirname, strlen(refname) + 1);
899 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
900 /* Expand dirname to the new prefix, not including the trailing slash: */
901 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
904 * We are still at a leading dir of the refname (e.g.,
905 * "refs/foo"; if there is a reference with that name,
906 * it is a conflict, *unless* it is in skip.
908 if (dir) {
909 pos = search_ref_dir(dir, dirname.buf, dirname.len);
910 if (pos >= 0 &&
911 (!skip || !string_list_has_string(skip, dirname.buf))) {
913 * We found a reference whose name is
914 * a proper prefix of refname; e.g.,
915 * "refs/foo", and is not in skip.
917 strbuf_addf(err, "'%s' exists; cannot create '%s'",
918 dirname.buf, refname);
919 goto cleanup;
923 if (extras && string_list_has_string(extras, dirname.buf) &&
924 (!skip || !string_list_has_string(skip, dirname.buf))) {
925 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
926 refname, dirname.buf);
927 goto cleanup;
931 * Otherwise, we can try to continue our search with
932 * the next component. So try to look up the
933 * directory, e.g., "refs/foo/". If we come up empty,
934 * we know there is nothing under this whole prefix,
935 * but even in that case we still have to continue the
936 * search for conflicts with extras.
938 strbuf_addch(&dirname, '/');
939 if (dir) {
940 pos = search_ref_dir(dir, dirname.buf, dirname.len);
941 if (pos < 0) {
943 * There was no directory "refs/foo/",
944 * so there is nothing under this
945 * whole prefix. So there is no need
946 * to continue looking for conflicting
947 * references. But we need to continue
948 * looking for conflicting extras.
950 dir = NULL;
951 } else {
952 dir = get_ref_dir(dir->entries[pos]);
958 * We are at the leaf of our refname (e.g., "refs/foo/bar").
959 * There is no point in searching for a reference with that
960 * name, because a refname isn't considered to conflict with
961 * itself. But we still need to check for references whose
962 * names are in the "refs/foo/bar/" namespace, because they
963 * *do* conflict.
965 strbuf_addstr(&dirname, refname + dirname.len);
966 strbuf_addch(&dirname, '/');
968 if (dir) {
969 pos = search_ref_dir(dir, dirname.buf, dirname.len);
971 if (pos >= 0) {
973 * We found a directory named "$refname/"
974 * (e.g., "refs/foo/bar/"). It is a problem
975 * iff it contains any ref that is not in
976 * "skip".
978 struct nonmatching_ref_data data;
980 data.skip = skip;
981 data.conflicting_refname = NULL;
982 dir = get_ref_dir(dir->entries[pos]);
983 sort_ref_dir(dir);
984 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
985 strbuf_addf(err, "'%s' exists; cannot create '%s'",
986 data.conflicting_refname, refname);
987 goto cleanup;
992 if (extras) {
994 * Check for entries in extras that start with
995 * "$refname/". We do that by looking for the place
996 * where "$refname/" would be inserted in extras. If
997 * there is an entry at that position that starts with
998 * "$refname/" and is not in skip, then we have a
999 * conflict.
1001 for (pos = string_list_find_insert_index(extras, dirname.buf, 0);
1002 pos < extras->nr; pos++) {
1003 const char *extra_refname = extras->items[pos].string;
1005 if (!starts_with(extra_refname, dirname.buf))
1006 break;
1008 if (!skip || !string_list_has_string(skip, extra_refname)) {
1009 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1010 refname, extra_refname);
1011 goto cleanup;
1016 /* No conflicts were found */
1017 ret = 0;
1019 cleanup:
1020 strbuf_release(&dirname);
1021 return ret;
1024 struct packed_ref_cache {
1025 struct ref_entry *root;
1028 * Count of references to the data structure in this instance,
1029 * including the pointer from ref_cache::packed if any. The
1030 * data will not be freed as long as the reference count is
1031 * nonzero.
1033 unsigned int referrers;
1036 * Iff the packed-refs file associated with this instance is
1037 * currently locked for writing, this points at the associated
1038 * lock (which is owned by somebody else). The referrer count
1039 * is also incremented when the file is locked and decremented
1040 * when it is unlocked.
1042 struct lock_file *lock;
1044 /* The metadata from when this packed-refs cache was read */
1045 struct stat_validity validity;
1049 * Future: need to be in "struct repository"
1050 * when doing a full libification.
1052 static struct ref_cache {
1053 struct ref_cache *next;
1054 struct ref_entry *loose;
1055 struct packed_ref_cache *packed;
1057 * The submodule name, or "" for the main repo. We allocate
1058 * length 1 rather than FLEX_ARRAY so that the main ref_cache
1059 * is initialized correctly.
1061 char name[1];
1062 } ref_cache, *submodule_ref_caches;
1064 /* Lock used for the main packed-refs file: */
1065 static struct lock_file packlock;
1068 * Increment the reference count of *packed_refs.
1070 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
1072 packed_refs->referrers++;
1076 * Decrease the reference count of *packed_refs. If it goes to zero,
1077 * free *packed_refs and return true; otherwise return false.
1079 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
1081 if (!--packed_refs->referrers) {
1082 free_ref_entry(packed_refs->root);
1083 stat_validity_clear(&packed_refs->validity);
1084 free(packed_refs);
1085 return 1;
1086 } else {
1087 return 0;
1091 static void clear_packed_ref_cache(struct ref_cache *refs)
1093 if (refs->packed) {
1094 struct packed_ref_cache *packed_refs = refs->packed;
1096 if (packed_refs->lock)
1097 die("internal error: packed-ref cache cleared while locked");
1098 refs->packed = NULL;
1099 release_packed_ref_cache(packed_refs);
1103 static void clear_loose_ref_cache(struct ref_cache *refs)
1105 if (refs->loose) {
1106 free_ref_entry(refs->loose);
1107 refs->loose = NULL;
1111 static struct ref_cache *create_ref_cache(const char *submodule)
1113 int len;
1114 struct ref_cache *refs;
1115 if (!submodule)
1116 submodule = "";
1117 len = strlen(submodule) + 1;
1118 refs = xcalloc(1, sizeof(struct ref_cache) + len);
1119 memcpy(refs->name, submodule, len);
1120 return refs;
1124 * Return a pointer to a ref_cache for the specified submodule. For
1125 * the main repository, use submodule==NULL. The returned structure
1126 * will be allocated and initialized but not necessarily populated; it
1127 * should not be freed.
1129 static struct ref_cache *get_ref_cache(const char *submodule)
1131 struct ref_cache *refs;
1133 if (!submodule || !*submodule)
1134 return &ref_cache;
1136 for (refs = submodule_ref_caches; refs; refs = refs->next)
1137 if (!strcmp(submodule, refs->name))
1138 return refs;
1140 refs = create_ref_cache(submodule);
1141 refs->next = submodule_ref_caches;
1142 submodule_ref_caches = refs;
1143 return refs;
1146 /* The length of a peeled reference line in packed-refs, including EOL: */
1147 #define PEELED_LINE_LENGTH 42
1150 * The packed-refs header line that we write out. Perhaps other
1151 * traits will be added later. The trailing space is required.
1153 static const char PACKED_REFS_HEADER[] =
1154 "# pack-refs with: peeled fully-peeled \n";
1157 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1158 * Return a pointer to the refname within the line (null-terminated),
1159 * or NULL if there was a problem.
1161 static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1163 const char *ref;
1166 * 42: the answer to everything.
1168 * In this case, it happens to be the answer to
1169 * 40 (length of sha1 hex representation)
1170 * +1 (space in between hex and name)
1171 * +1 (newline at the end of the line)
1173 if (line->len <= 42)
1174 return NULL;
1176 if (get_sha1_hex(line->buf, sha1) < 0)
1177 return NULL;
1178 if (!isspace(line->buf[40]))
1179 return NULL;
1181 ref = line->buf + 41;
1182 if (isspace(*ref))
1183 return NULL;
1185 if (line->buf[line->len - 1] != '\n')
1186 return NULL;
1187 line->buf[--line->len] = 0;
1189 return ref;
1193 * Read f, which is a packed-refs file, into dir.
1195 * A comment line of the form "# pack-refs with: " may contain zero or
1196 * more traits. We interpret the traits as follows:
1198 * No traits:
1200 * Probably no references are peeled. But if the file contains a
1201 * peeled value for a reference, we will use it.
1203 * peeled:
1205 * References under "refs/tags/", if they *can* be peeled, *are*
1206 * peeled in this file. References outside of "refs/tags/" are
1207 * probably not peeled even if they could have been, but if we find
1208 * a peeled value for such a reference we will use it.
1210 * fully-peeled:
1212 * All references in the file that can be peeled are peeled.
1213 * Inversely (and this is more important), any references in the
1214 * file for which no peeled value is recorded is not peelable. This
1215 * trait should typically be written alongside "peeled" for
1216 * compatibility with older clients, but we do not require it
1217 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1219 static void read_packed_refs(FILE *f, struct ref_dir *dir)
1221 struct ref_entry *last = NULL;
1222 struct strbuf line = STRBUF_INIT;
1223 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1225 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1226 unsigned char sha1[20];
1227 const char *refname;
1228 const char *traits;
1230 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1231 if (strstr(traits, " fully-peeled "))
1232 peeled = PEELED_FULLY;
1233 else if (strstr(traits, " peeled "))
1234 peeled = PEELED_TAGS;
1235 /* perhaps other traits later as well */
1236 continue;
1239 refname = parse_ref_line(&line, sha1);
1240 if (refname) {
1241 int flag = REF_ISPACKED;
1243 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1244 if (!refname_is_safe(refname))
1245 die("packed refname is dangerous: %s", refname);
1246 hashclr(sha1);
1247 flag |= REF_BAD_NAME | REF_ISBROKEN;
1249 last = create_ref_entry(refname, sha1, flag, 0);
1250 if (peeled == PEELED_FULLY ||
1251 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1252 last->flag |= REF_KNOWS_PEELED;
1253 add_ref(dir, last);
1254 continue;
1256 if (last &&
1257 line.buf[0] == '^' &&
1258 line.len == PEELED_LINE_LENGTH &&
1259 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1260 !get_sha1_hex(line.buf + 1, sha1)) {
1261 hashcpy(last->u.value.peeled.hash, sha1);
1263 * Regardless of what the file header said,
1264 * we definitely know the value of *this*
1265 * reference:
1267 last->flag |= REF_KNOWS_PEELED;
1271 strbuf_release(&line);
1275 * Get the packed_ref_cache for the specified ref_cache, creating it
1276 * if necessary.
1278 static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1280 const char *packed_refs_file;
1282 if (*refs->name)
1283 packed_refs_file = git_path_submodule(refs->name, "packed-refs");
1284 else
1285 packed_refs_file = git_path("packed-refs");
1287 if (refs->packed &&
1288 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1289 clear_packed_ref_cache(refs);
1291 if (!refs->packed) {
1292 FILE *f;
1294 refs->packed = xcalloc(1, sizeof(*refs->packed));
1295 acquire_packed_ref_cache(refs->packed);
1296 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1297 f = fopen(packed_refs_file, "r");
1298 if (f) {
1299 stat_validity_update(&refs->packed->validity, fileno(f));
1300 read_packed_refs(f, get_ref_dir(refs->packed->root));
1301 fclose(f);
1304 return refs->packed;
1307 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1309 return get_ref_dir(packed_ref_cache->root);
1312 static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1314 return get_packed_ref_dir(get_packed_ref_cache(refs));
1317 void add_packed_ref(const char *refname, const unsigned char *sha1)
1319 struct packed_ref_cache *packed_ref_cache =
1320 get_packed_ref_cache(&ref_cache);
1322 if (!packed_ref_cache->lock)
1323 die("internal error: packed refs not locked");
1324 add_ref(get_packed_ref_dir(packed_ref_cache),
1325 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1329 * Read the loose references from the namespace dirname into dir
1330 * (without recursing). dirname must end with '/'. dir must be the
1331 * directory entry corresponding to dirname.
1333 static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1335 struct ref_cache *refs = dir->ref_cache;
1336 DIR *d;
1337 const char *path;
1338 struct dirent *de;
1339 int dirnamelen = strlen(dirname);
1340 struct strbuf refname;
1342 if (*refs->name)
1343 path = git_path_submodule(refs->name, "%s", dirname);
1344 else
1345 path = git_path("%s", dirname);
1347 d = opendir(path);
1348 if (!d)
1349 return;
1351 strbuf_init(&refname, dirnamelen + 257);
1352 strbuf_add(&refname, dirname, dirnamelen);
1354 while ((de = readdir(d)) != NULL) {
1355 unsigned char sha1[20];
1356 struct stat st;
1357 int flag;
1358 const char *refdir;
1360 if (de->d_name[0] == '.')
1361 continue;
1362 if (ends_with(de->d_name, ".lock"))
1363 continue;
1364 strbuf_addstr(&refname, de->d_name);
1365 refdir = *refs->name
1366 ? git_path_submodule(refs->name, "%s", refname.buf)
1367 : git_path("%s", refname.buf);
1368 if (stat(refdir, &st) < 0) {
1369 ; /* silently ignore */
1370 } else if (S_ISDIR(st.st_mode)) {
1371 strbuf_addch(&refname, '/');
1372 add_entry_to_dir(dir,
1373 create_dir_entry(refs, refname.buf,
1374 refname.len, 1));
1375 } else {
1376 int read_ok;
1378 if (*refs->name) {
1379 hashclr(sha1);
1380 flag = 0;
1381 read_ok = !resolve_gitlink_ref(refs->name,
1382 refname.buf, sha1);
1383 } else {
1384 read_ok = !read_ref_full(refname.buf,
1385 RESOLVE_REF_READING,
1386 sha1, &flag);
1389 if (!read_ok) {
1390 hashclr(sha1);
1391 flag |= REF_ISBROKEN;
1392 } else if (is_null_sha1(sha1)) {
1394 * It is so astronomically unlikely
1395 * that NULL_SHA1 is the SHA-1 of an
1396 * actual object that we consider its
1397 * appearance in a loose reference
1398 * file to be repo corruption
1399 * (probably due to a software bug).
1401 flag |= REF_ISBROKEN;
1404 if (check_refname_format(refname.buf,
1405 REFNAME_ALLOW_ONELEVEL)) {
1406 if (!refname_is_safe(refname.buf))
1407 die("loose refname is dangerous: %s", refname.buf);
1408 hashclr(sha1);
1409 flag |= REF_BAD_NAME | REF_ISBROKEN;
1411 add_entry_to_dir(dir,
1412 create_ref_entry(refname.buf, sha1, flag, 0));
1414 strbuf_setlen(&refname, dirnamelen);
1416 strbuf_release(&refname);
1417 closedir(d);
1420 static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1422 if (!refs->loose) {
1424 * Mark the top-level directory complete because we
1425 * are about to read the only subdirectory that can
1426 * hold references:
1428 refs->loose = create_dir_entry(refs, "", 0, 0);
1430 * Create an incomplete entry for "refs/":
1432 add_entry_to_dir(get_ref_dir(refs->loose),
1433 create_dir_entry(refs, "refs/", 5, 1));
1435 return get_ref_dir(refs->loose);
1438 /* We allow "recursive" symbolic refs. Only within reason, though */
1439 #define MAXDEPTH 5
1440 #define MAXREFLEN (1024)
1443 * Called by resolve_gitlink_ref_recursive() after it failed to read
1444 * from the loose refs in ref_cache refs. Find <refname> in the
1445 * packed-refs file for the submodule.
1447 static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1448 const char *refname, unsigned char *sha1)
1450 struct ref_entry *ref;
1451 struct ref_dir *dir = get_packed_refs(refs);
1453 ref = find_ref(dir, refname);
1454 if (ref == NULL)
1455 return -1;
1457 hashcpy(sha1, ref->u.value.oid.hash);
1458 return 0;
1461 static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1462 const char *refname, unsigned char *sha1,
1463 int recursion)
1465 int fd, len;
1466 char buffer[128], *p;
1467 const char *path;
1469 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1470 return -1;
1471 path = *refs->name
1472 ? git_path_submodule(refs->name, "%s", refname)
1473 : git_path("%s", refname);
1474 fd = open(path, O_RDONLY);
1475 if (fd < 0)
1476 return resolve_gitlink_packed_ref(refs, refname, sha1);
1478 len = read(fd, buffer, sizeof(buffer)-1);
1479 close(fd);
1480 if (len < 0)
1481 return -1;
1482 while (len && isspace(buffer[len-1]))
1483 len--;
1484 buffer[len] = 0;
1486 /* Was it a detached head or an old-fashioned symlink? */
1487 if (!get_sha1_hex(buffer, sha1))
1488 return 0;
1490 /* Symref? */
1491 if (strncmp(buffer, "ref:", 4))
1492 return -1;
1493 p = buffer + 4;
1494 while (isspace(*p))
1495 p++;
1497 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1500 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1502 int len = strlen(path), retval;
1503 char *submodule;
1504 struct ref_cache *refs;
1506 while (len && path[len-1] == '/')
1507 len--;
1508 if (!len)
1509 return -1;
1510 submodule = xstrndup(path, len);
1511 refs = get_ref_cache(submodule);
1512 free(submodule);
1514 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1515 return retval;
1519 * Return the ref_entry for the given refname from the packed
1520 * references. If it does not exist, return NULL.
1522 static struct ref_entry *get_packed_ref(const char *refname)
1524 return find_ref(get_packed_refs(&ref_cache), refname);
1528 * A loose ref file doesn't exist; check for a packed ref. The
1529 * options are forwarded from resolve_safe_unsafe().
1531 static int resolve_missing_loose_ref(const char *refname,
1532 int resolve_flags,
1533 unsigned char *sha1,
1534 int *flags)
1536 struct ref_entry *entry;
1539 * The loose reference file does not exist; check for a packed
1540 * reference.
1542 entry = get_packed_ref(refname);
1543 if (entry) {
1544 hashcpy(sha1, entry->u.value.oid.hash);
1545 if (flags)
1546 *flags |= REF_ISPACKED;
1547 return 0;
1549 /* The reference is not a packed reference, either. */
1550 if (resolve_flags & RESOLVE_REF_READING) {
1551 errno = ENOENT;
1552 return -1;
1553 } else {
1554 hashclr(sha1);
1555 return 0;
1559 /* This function needs to return a meaningful errno on failure */
1560 static const char *resolve_ref_unsafe_1(const char *refname,
1561 int resolve_flags,
1562 unsigned char *sha1,
1563 int *flags,
1564 struct strbuf *sb_path)
1566 int depth = MAXDEPTH;
1567 ssize_t len;
1568 char buffer[256];
1569 static char refname_buffer[256];
1570 int bad_name = 0;
1572 if (flags)
1573 *flags = 0;
1575 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1576 if (flags)
1577 *flags |= REF_BAD_NAME;
1579 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1580 !refname_is_safe(refname)) {
1581 errno = EINVAL;
1582 return NULL;
1585 * dwim_ref() uses REF_ISBROKEN to distinguish between
1586 * missing refs and refs that were present but invalid,
1587 * to complain about the latter to stderr.
1589 * We don't know whether the ref exists, so don't set
1590 * REF_ISBROKEN yet.
1592 bad_name = 1;
1594 for (;;) {
1595 const char *path;
1596 struct stat st;
1597 char *buf;
1598 int fd;
1600 if (--depth < 0) {
1601 errno = ELOOP;
1602 return NULL;
1605 strbuf_reset(sb_path);
1606 strbuf_git_path(sb_path, "%s", refname);
1607 path = sb_path->buf;
1610 * We might have to loop back here to avoid a race
1611 * condition: first we lstat() the file, then we try
1612 * to read it as a link or as a file. But if somebody
1613 * changes the type of the file (file <-> directory
1614 * <-> symlink) between the lstat() and reading, then
1615 * we don't want to report that as an error but rather
1616 * try again starting with the lstat().
1618 stat_ref:
1619 if (lstat(path, &st) < 0) {
1620 if (errno != ENOENT)
1621 return NULL;
1622 if (resolve_missing_loose_ref(refname, resolve_flags,
1623 sha1, flags))
1624 return NULL;
1625 if (bad_name) {
1626 hashclr(sha1);
1627 if (flags)
1628 *flags |= REF_ISBROKEN;
1630 return refname;
1633 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1634 if (S_ISLNK(st.st_mode)) {
1635 len = readlink(path, buffer, sizeof(buffer)-1);
1636 if (len < 0) {
1637 if (errno == ENOENT || errno == EINVAL)
1638 /* inconsistent with lstat; retry */
1639 goto stat_ref;
1640 else
1641 return NULL;
1643 buffer[len] = 0;
1644 if (starts_with(buffer, "refs/") &&
1645 !check_refname_format(buffer, 0)) {
1646 strcpy(refname_buffer, buffer);
1647 refname = refname_buffer;
1648 if (flags)
1649 *flags |= REF_ISSYMREF;
1650 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1651 hashclr(sha1);
1652 return refname;
1654 continue;
1658 /* Is it a directory? */
1659 if (S_ISDIR(st.st_mode)) {
1660 errno = EISDIR;
1661 return NULL;
1665 * Anything else, just open it and try to use it as
1666 * a ref
1668 fd = open(path, O_RDONLY);
1669 if (fd < 0) {
1670 if (errno == ENOENT)
1671 /* inconsistent with lstat; retry */
1672 goto stat_ref;
1673 else
1674 return NULL;
1676 len = read_in_full(fd, buffer, sizeof(buffer)-1);
1677 if (len < 0) {
1678 int save_errno = errno;
1679 close(fd);
1680 errno = save_errno;
1681 return NULL;
1683 close(fd);
1684 while (len && isspace(buffer[len-1]))
1685 len--;
1686 buffer[len] = '\0';
1689 * Is it a symbolic ref?
1691 if (!starts_with(buffer, "ref:")) {
1693 * Please note that FETCH_HEAD has a second
1694 * line containing other data.
1696 if (get_sha1_hex(buffer, sha1) ||
1697 (buffer[40] != '\0' && !isspace(buffer[40]))) {
1698 if (flags)
1699 *flags |= REF_ISBROKEN;
1700 errno = EINVAL;
1701 return NULL;
1703 if (bad_name) {
1704 hashclr(sha1);
1705 if (flags)
1706 *flags |= REF_ISBROKEN;
1708 return refname;
1710 if (flags)
1711 *flags |= REF_ISSYMREF;
1712 buf = buffer + 4;
1713 while (isspace(*buf))
1714 buf++;
1715 refname = strcpy(refname_buffer, buf);
1716 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1717 hashclr(sha1);
1718 return refname;
1720 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1721 if (flags)
1722 *flags |= REF_ISBROKEN;
1724 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1725 !refname_is_safe(buf)) {
1726 errno = EINVAL;
1727 return NULL;
1729 bad_name = 1;
1734 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1735 unsigned char *sha1, int *flags)
1737 struct strbuf sb_path = STRBUF_INIT;
1738 const char *ret = resolve_ref_unsafe_1(refname, resolve_flags,
1739 sha1, flags, &sb_path);
1740 strbuf_release(&sb_path);
1741 return ret;
1744 char *resolve_refdup(const char *ref, int resolve_flags, unsigned char *sha1, int *flags)
1746 return xstrdup_or_null(resolve_ref_unsafe(ref, resolve_flags, sha1, flags));
1749 /* The argument to filter_refs */
1750 struct ref_filter {
1751 const char *pattern;
1752 each_ref_fn *fn;
1753 void *cb_data;
1756 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1758 if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
1759 return 0;
1760 return -1;
1763 int read_ref(const char *refname, unsigned char *sha1)
1765 return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
1768 int ref_exists(const char *refname)
1770 unsigned char sha1[20];
1771 return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
1774 static int filter_refs(const char *refname, const struct object_id *oid,
1775 int flags, void *data)
1777 struct ref_filter *filter = (struct ref_filter *)data;
1779 if (wildmatch(filter->pattern, refname, 0, NULL))
1780 return 0;
1781 return filter->fn(refname, oid, flags, filter->cb_data);
1784 enum peel_status {
1785 /* object was peeled successfully: */
1786 PEEL_PEELED = 0,
1789 * object cannot be peeled because the named object (or an
1790 * object referred to by a tag in the peel chain), does not
1791 * exist.
1793 PEEL_INVALID = -1,
1795 /* object cannot be peeled because it is not a tag: */
1796 PEEL_NON_TAG = -2,
1798 /* ref_entry contains no peeled value because it is a symref: */
1799 PEEL_IS_SYMREF = -3,
1802 * ref_entry cannot be peeled because it is broken (i.e., the
1803 * symbolic reference cannot even be resolved to an object
1804 * name):
1806 PEEL_BROKEN = -4
1810 * Peel the named object; i.e., if the object is a tag, resolve the
1811 * tag recursively until a non-tag is found. If successful, store the
1812 * result to sha1 and return PEEL_PEELED. If the object is not a tag
1813 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
1814 * and leave sha1 unchanged.
1816 static enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
1818 struct object *o = lookup_unknown_object(name);
1820 if (o->type == OBJ_NONE) {
1821 int type = sha1_object_info(name, NULL);
1822 if (type < 0 || !object_as_type(o, type, 0))
1823 return PEEL_INVALID;
1826 if (o->type != OBJ_TAG)
1827 return PEEL_NON_TAG;
1829 o = deref_tag_noverify(o);
1830 if (!o)
1831 return PEEL_INVALID;
1833 hashcpy(sha1, o->sha1);
1834 return PEEL_PEELED;
1838 * Peel the entry (if possible) and return its new peel_status. If
1839 * repeel is true, re-peel the entry even if there is an old peeled
1840 * value that is already stored in it.
1842 * It is OK to call this function with a packed reference entry that
1843 * might be stale and might even refer to an object that has since
1844 * been garbage-collected. In such a case, if the entry has
1845 * REF_KNOWS_PEELED then leave the status unchanged and return
1846 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1848 static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1850 enum peel_status status;
1852 if (entry->flag & REF_KNOWS_PEELED) {
1853 if (repeel) {
1854 entry->flag &= ~REF_KNOWS_PEELED;
1855 oidclr(&entry->u.value.peeled);
1856 } else {
1857 return is_null_oid(&entry->u.value.peeled) ?
1858 PEEL_NON_TAG : PEEL_PEELED;
1861 if (entry->flag & REF_ISBROKEN)
1862 return PEEL_BROKEN;
1863 if (entry->flag & REF_ISSYMREF)
1864 return PEEL_IS_SYMREF;
1866 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1867 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1868 entry->flag |= REF_KNOWS_PEELED;
1869 return status;
1872 int peel_ref(const char *refname, unsigned char *sha1)
1874 int flag;
1875 unsigned char base[20];
1877 if (current_ref && (current_ref->name == refname
1878 || !strcmp(current_ref->name, refname))) {
1879 if (peel_entry(current_ref, 0))
1880 return -1;
1881 hashcpy(sha1, current_ref->u.value.peeled.hash);
1882 return 0;
1885 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1886 return -1;
1889 * If the reference is packed, read its ref_entry from the
1890 * cache in the hope that we already know its peeled value.
1891 * We only try this optimization on packed references because
1892 * (a) forcing the filling of the loose reference cache could
1893 * be expensive and (b) loose references anyway usually do not
1894 * have REF_KNOWS_PEELED.
1896 if (flag & REF_ISPACKED) {
1897 struct ref_entry *r = get_packed_ref(refname);
1898 if (r) {
1899 if (peel_entry(r, 0))
1900 return -1;
1901 hashcpy(sha1, r->u.value.peeled.hash);
1902 return 0;
1906 return peel_object(base, sha1);
1909 struct warn_if_dangling_data {
1910 FILE *fp;
1911 const char *refname;
1912 const struct string_list *refnames;
1913 const char *msg_fmt;
1916 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
1917 int flags, void *cb_data)
1919 struct warn_if_dangling_data *d = cb_data;
1920 const char *resolves_to;
1921 struct object_id junk;
1923 if (!(flags & REF_ISSYMREF))
1924 return 0;
1926 resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
1927 if (!resolves_to
1928 || (d->refname
1929 ? strcmp(resolves_to, d->refname)
1930 : !string_list_has_string(d->refnames, resolves_to))) {
1931 return 0;
1934 fprintf(d->fp, d->msg_fmt, refname);
1935 fputc('\n', d->fp);
1936 return 0;
1939 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1941 struct warn_if_dangling_data data;
1943 data.fp = fp;
1944 data.refname = refname;
1945 data.refnames = NULL;
1946 data.msg_fmt = msg_fmt;
1947 for_each_rawref(warn_if_dangling_symref, &data);
1950 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
1952 struct warn_if_dangling_data data;
1954 data.fp = fp;
1955 data.refname = NULL;
1956 data.refnames = refnames;
1957 data.msg_fmt = msg_fmt;
1958 for_each_rawref(warn_if_dangling_symref, &data);
1962 * Call fn for each reference in the specified ref_cache, omitting
1963 * references not in the containing_dir of base. fn is called for all
1964 * references, including broken ones. If fn ever returns a non-zero
1965 * value, stop the iteration and return that value; otherwise, return
1966 * 0.
1968 static int do_for_each_entry(struct ref_cache *refs, const char *base,
1969 each_ref_entry_fn fn, void *cb_data)
1971 struct packed_ref_cache *packed_ref_cache;
1972 struct ref_dir *loose_dir;
1973 struct ref_dir *packed_dir;
1974 int retval = 0;
1977 * We must make sure that all loose refs are read before accessing the
1978 * packed-refs file; this avoids a race condition in which loose refs
1979 * are migrated to the packed-refs file by a simultaneous process, but
1980 * our in-memory view is from before the migration. get_packed_ref_cache()
1981 * takes care of making sure our view is up to date with what is on
1982 * disk.
1984 loose_dir = get_loose_refs(refs);
1985 if (base && *base) {
1986 loose_dir = find_containing_dir(loose_dir, base, 0);
1988 if (loose_dir)
1989 prime_ref_dir(loose_dir);
1991 packed_ref_cache = get_packed_ref_cache(refs);
1992 acquire_packed_ref_cache(packed_ref_cache);
1993 packed_dir = get_packed_ref_dir(packed_ref_cache);
1994 if (base && *base) {
1995 packed_dir = find_containing_dir(packed_dir, base, 0);
1998 if (packed_dir && loose_dir) {
1999 sort_ref_dir(packed_dir);
2000 sort_ref_dir(loose_dir);
2001 retval = do_for_each_entry_in_dirs(
2002 packed_dir, loose_dir, fn, cb_data);
2003 } else if (packed_dir) {
2004 sort_ref_dir(packed_dir);
2005 retval = do_for_each_entry_in_dir(
2006 packed_dir, 0, fn, cb_data);
2007 } else if (loose_dir) {
2008 sort_ref_dir(loose_dir);
2009 retval = do_for_each_entry_in_dir(
2010 loose_dir, 0, fn, cb_data);
2013 release_packed_ref_cache(packed_ref_cache);
2014 return retval;
2018 * Call fn for each reference in the specified ref_cache for which the
2019 * refname begins with base. If trim is non-zero, then trim that many
2020 * characters off the beginning of each refname before passing the
2021 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
2022 * broken references in the iteration. If fn ever returns a non-zero
2023 * value, stop the iteration and return that value; otherwise, return
2024 * 0.
2026 static int do_for_each_ref(struct ref_cache *refs, const char *base,
2027 each_ref_fn fn, int trim, int flags, void *cb_data)
2029 struct ref_entry_cb data;
2030 data.base = base;
2031 data.trim = trim;
2032 data.flags = flags;
2033 data.fn = fn;
2034 data.cb_data = cb_data;
2036 if (ref_paranoia < 0)
2037 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
2038 if (ref_paranoia)
2039 data.flags |= DO_FOR_EACH_INCLUDE_BROKEN;
2041 return do_for_each_entry(refs, base, do_one_ref, &data);
2044 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
2046 struct object_id oid;
2047 int flag;
2049 if (submodule) {
2050 if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
2051 return fn("HEAD", &oid, 0, cb_data);
2053 return 0;
2056 if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
2057 return fn("HEAD", &oid, flag, cb_data);
2059 return 0;
2062 int head_ref(each_ref_fn fn, void *cb_data)
2064 return do_head_ref(NULL, fn, cb_data);
2067 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2069 return do_head_ref(submodule, fn, cb_data);
2072 int for_each_ref(each_ref_fn fn, void *cb_data)
2074 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
2077 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2079 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
2082 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
2084 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
2087 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
2088 each_ref_fn fn, void *cb_data)
2090 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
2093 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
2095 return for_each_ref_in("refs/tags/", fn, cb_data);
2098 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2100 return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
2103 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
2105 return for_each_ref_in("refs/heads/", fn, cb_data);
2108 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2110 return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
2113 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
2115 return for_each_ref_in("refs/remotes/", fn, cb_data);
2118 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2120 return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
2123 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
2125 return do_for_each_ref(&ref_cache, "refs/replace/", fn, 13, 0, cb_data);
2128 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
2130 struct strbuf buf = STRBUF_INIT;
2131 int ret = 0;
2132 struct object_id oid;
2133 int flag;
2135 strbuf_addf(&buf, "%sHEAD", get_git_namespace());
2136 if (!read_ref_full(buf.buf, RESOLVE_REF_READING, oid.hash, &flag))
2137 ret = fn(buf.buf, &oid, flag, cb_data);
2138 strbuf_release(&buf);
2140 return ret;
2143 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
2145 struct strbuf buf = STRBUF_INIT;
2146 int ret;
2147 strbuf_addf(&buf, "%srefs/", get_git_namespace());
2148 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
2149 strbuf_release(&buf);
2150 return ret;
2153 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
2154 const char *prefix, void *cb_data)
2156 struct strbuf real_pattern = STRBUF_INIT;
2157 struct ref_filter filter;
2158 int ret;
2160 if (!prefix && !starts_with(pattern, "refs/"))
2161 strbuf_addstr(&real_pattern, "refs/");
2162 else if (prefix)
2163 strbuf_addstr(&real_pattern, prefix);
2164 strbuf_addstr(&real_pattern, pattern);
2166 if (!has_glob_specials(pattern)) {
2167 /* Append implied '/' '*' if not present. */
2168 if (real_pattern.buf[real_pattern.len - 1] != '/')
2169 strbuf_addch(&real_pattern, '/');
2170 /* No need to check for '*', there is none. */
2171 strbuf_addch(&real_pattern, '*');
2174 filter.pattern = real_pattern.buf;
2175 filter.fn = fn;
2176 filter.cb_data = cb_data;
2177 ret = for_each_ref(filter_refs, &filter);
2179 strbuf_release(&real_pattern);
2180 return ret;
2183 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
2185 return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
2188 int for_each_rawref(each_ref_fn fn, void *cb_data)
2190 return do_for_each_ref(&ref_cache, "", fn, 0,
2191 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
2194 const char *prettify_refname(const char *name)
2196 return name + (
2197 starts_with(name, "refs/heads/") ? 11 :
2198 starts_with(name, "refs/tags/") ? 10 :
2199 starts_with(name, "refs/remotes/") ? 13 :
2203 static const char *ref_rev_parse_rules[] = {
2204 "%.*s",
2205 "refs/%.*s",
2206 "refs/tags/%.*s",
2207 "refs/heads/%.*s",
2208 "refs/remotes/%.*s",
2209 "refs/remotes/%.*s/HEAD",
2210 NULL
2213 int refname_match(const char *abbrev_name, const char *full_name)
2215 const char **p;
2216 const int abbrev_name_len = strlen(abbrev_name);
2218 for (p = ref_rev_parse_rules; *p; p++) {
2219 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
2220 return 1;
2224 return 0;
2227 static void unlock_ref(struct ref_lock *lock)
2229 /* Do not free lock->lk -- atexit() still looks at them */
2230 if (lock->lk)
2231 rollback_lock_file(lock->lk);
2232 free(lock->ref_name);
2233 free(lock->orig_ref_name);
2234 free(lock);
2238 * Verify that the reference locked by lock has the value old_sha1.
2239 * Fail if the reference doesn't exist and mustexist is set. Return 0
2240 * on success. On error, write an error message to err, set errno, and
2241 * return a negative value.
2243 static int verify_lock(struct ref_lock *lock,
2244 const unsigned char *old_sha1, int mustexist,
2245 struct strbuf *err)
2247 assert(err);
2249 if (read_ref_full(lock->ref_name,
2250 mustexist ? RESOLVE_REF_READING : 0,
2251 lock->old_oid.hash, NULL)) {
2252 int save_errno = errno;
2253 strbuf_addf(err, "can't verify ref %s", lock->ref_name);
2254 errno = save_errno;
2255 return -1;
2257 if (hashcmp(lock->old_oid.hash, old_sha1)) {
2258 strbuf_addf(err, "ref %s is at %s but expected %s",
2259 lock->ref_name,
2260 sha1_to_hex(lock->old_oid.hash),
2261 sha1_to_hex(old_sha1));
2262 errno = EBUSY;
2263 return -1;
2265 return 0;
2268 static int remove_empty_directories(const char *file)
2270 /* we want to create a file but there is a directory there;
2271 * if that is an empty directory (or a directory that contains
2272 * only empty directories), remove them.
2274 struct strbuf path;
2275 int result, save_errno;
2277 strbuf_init(&path, 20);
2278 strbuf_addstr(&path, file);
2280 result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
2281 save_errno = errno;
2283 strbuf_release(&path);
2284 errno = save_errno;
2286 return result;
2290 * *string and *len will only be substituted, and *string returned (for
2291 * later free()ing) if the string passed in is a magic short-hand form
2292 * to name a branch.
2294 static char *substitute_branch_name(const char **string, int *len)
2296 struct strbuf buf = STRBUF_INIT;
2297 int ret = interpret_branch_name(*string, *len, &buf);
2299 if (ret == *len) {
2300 size_t size;
2301 *string = strbuf_detach(&buf, &size);
2302 *len = size;
2303 return (char *)*string;
2306 return NULL;
2309 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
2311 char *last_branch = substitute_branch_name(&str, &len);
2312 const char **p, *r;
2313 int refs_found = 0;
2315 *ref = NULL;
2316 for (p = ref_rev_parse_rules; *p; p++) {
2317 char fullref[PATH_MAX];
2318 unsigned char sha1_from_ref[20];
2319 unsigned char *this_result;
2320 int flag;
2322 this_result = refs_found ? sha1_from_ref : sha1;
2323 mksnpath(fullref, sizeof(fullref), *p, len, str);
2324 r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
2325 this_result, &flag);
2326 if (r) {
2327 if (!refs_found++)
2328 *ref = xstrdup(r);
2329 if (!warn_ambiguous_refs)
2330 break;
2331 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
2332 warning("ignoring dangling symref %s.", fullref);
2333 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
2334 warning("ignoring broken ref %s.", fullref);
2337 free(last_branch);
2338 return refs_found;
2341 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
2343 char *last_branch = substitute_branch_name(&str, &len);
2344 const char **p;
2345 int logs_found = 0;
2347 *log = NULL;
2348 for (p = ref_rev_parse_rules; *p; p++) {
2349 unsigned char hash[20];
2350 char path[PATH_MAX];
2351 const char *ref, *it;
2353 mksnpath(path, sizeof(path), *p, len, str);
2354 ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
2355 hash, NULL);
2356 if (!ref)
2357 continue;
2358 if (reflog_exists(path))
2359 it = path;
2360 else if (strcmp(ref, path) && reflog_exists(ref))
2361 it = ref;
2362 else
2363 continue;
2364 if (!logs_found++) {
2365 *log = xstrdup(it);
2366 hashcpy(sha1, hash);
2368 if (!warn_ambiguous_refs)
2369 break;
2371 free(last_branch);
2372 return logs_found;
2376 * Locks a ref returning the lock on success and NULL on failure.
2377 * On failure errno is set to something meaningful.
2379 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2380 const unsigned char *old_sha1,
2381 const struct string_list *extras,
2382 const struct string_list *skip,
2383 unsigned int flags, int *type_p,
2384 struct strbuf *err)
2386 const char *ref_file;
2387 const char *orig_refname = refname;
2388 struct ref_lock *lock;
2389 int last_errno = 0;
2390 int type, lflags;
2391 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
2392 int resolve_flags = 0;
2393 int attempts_remaining = 3;
2395 assert(err);
2397 lock = xcalloc(1, sizeof(struct ref_lock));
2399 if (mustexist)
2400 resolve_flags |= RESOLVE_REF_READING;
2401 if (flags & REF_DELETING) {
2402 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
2403 if (flags & REF_NODEREF)
2404 resolve_flags |= RESOLVE_REF_NO_RECURSE;
2407 refname = resolve_ref_unsafe(refname, resolve_flags,
2408 lock->old_oid.hash, &type);
2409 if (!refname && errno == EISDIR) {
2410 /* we are trying to lock foo but we used to
2411 * have foo/bar which now does not exist;
2412 * it is normal for the empty directory 'foo'
2413 * to remain.
2415 ref_file = git_path("%s", orig_refname);
2416 if (remove_empty_directories(ref_file)) {
2417 last_errno = errno;
2419 if (!verify_refname_available(orig_refname, extras, skip,
2420 get_loose_refs(&ref_cache), err))
2421 strbuf_addf(err, "there are still refs under '%s'",
2422 orig_refname);
2424 goto error_return;
2426 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
2427 lock->old_oid.hash, &type);
2429 if (type_p)
2430 *type_p = type;
2431 if (!refname) {
2432 last_errno = errno;
2433 if (last_errno != ENOTDIR ||
2434 !verify_refname_available(orig_refname, extras, skip,
2435 get_loose_refs(&ref_cache), err))
2436 strbuf_addf(err, "unable to resolve reference %s: %s",
2437 orig_refname, strerror(last_errno));
2439 goto error_return;
2442 * If the ref did not exist and we are creating it, make sure
2443 * there is no existing packed ref whose name begins with our
2444 * refname, nor a packed ref whose name is a proper prefix of
2445 * our refname.
2447 if (is_null_oid(&lock->old_oid) &&
2448 verify_refname_available(refname, extras, skip,
2449 get_packed_refs(&ref_cache), err)) {
2450 last_errno = ENOTDIR;
2451 goto error_return;
2454 lock->lk = xcalloc(1, sizeof(struct lock_file));
2456 lflags = 0;
2457 if (flags & REF_NODEREF) {
2458 refname = orig_refname;
2459 lflags |= LOCK_NO_DEREF;
2461 lock->ref_name = xstrdup(refname);
2462 lock->orig_ref_name = xstrdup(orig_refname);
2463 ref_file = git_path("%s", refname);
2465 retry:
2466 switch (safe_create_leading_directories_const(ref_file)) {
2467 case SCLD_OK:
2468 break; /* success */
2469 case SCLD_VANISHED:
2470 if (--attempts_remaining > 0)
2471 goto retry;
2472 /* fall through */
2473 default:
2474 last_errno = errno;
2475 strbuf_addf(err, "unable to create directory for %s", ref_file);
2476 goto error_return;
2479 if (hold_lock_file_for_update(lock->lk, ref_file, lflags) < 0) {
2480 last_errno = errno;
2481 if (errno == ENOENT && --attempts_remaining > 0)
2483 * Maybe somebody just deleted one of the
2484 * directories leading to ref_file. Try
2485 * again:
2487 goto retry;
2488 else {
2489 unable_to_lock_message(ref_file, errno, err);
2490 goto error_return;
2493 if (old_sha1 && verify_lock(lock, old_sha1, mustexist, err)) {
2494 last_errno = errno;
2495 goto error_return;
2497 return lock;
2499 error_return:
2500 unlock_ref(lock);
2501 errno = last_errno;
2502 return NULL;
2506 * Write an entry to the packed-refs file for the specified refname.
2507 * If peeled is non-NULL, write it as the entry's peeled value.
2509 static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2510 unsigned char *peeled)
2512 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2513 if (peeled)
2514 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2518 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2520 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2522 enum peel_status peel_status = peel_entry(entry, 0);
2524 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2525 error("internal error: %s is not a valid packed reference!",
2526 entry->name);
2527 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2528 peel_status == PEEL_PEELED ?
2529 entry->u.value.peeled.hash : NULL);
2530 return 0;
2533 /* This should return a meaningful errno on failure */
2534 int lock_packed_refs(int flags)
2536 static int timeout_configured = 0;
2537 static int timeout_value = 1000;
2539 struct packed_ref_cache *packed_ref_cache;
2541 if (!timeout_configured) {
2542 git_config_get_int("core.packedrefstimeout", &timeout_value);
2543 timeout_configured = 1;
2546 if (hold_lock_file_for_update_timeout(
2547 &packlock, git_path("packed-refs"),
2548 flags, timeout_value) < 0)
2549 return -1;
2551 * Get the current packed-refs while holding the lock. If the
2552 * packed-refs file has been modified since we last read it,
2553 * this will automatically invalidate the cache and re-read
2554 * the packed-refs file.
2556 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2557 packed_ref_cache->lock = &packlock;
2558 /* Increment the reference count to prevent it from being freed: */
2559 acquire_packed_ref_cache(packed_ref_cache);
2560 return 0;
2564 * Commit the packed refs changes.
2565 * On error we must make sure that errno contains a meaningful value.
2567 int commit_packed_refs(void)
2569 struct packed_ref_cache *packed_ref_cache =
2570 get_packed_ref_cache(&ref_cache);
2571 int error = 0;
2572 int save_errno = 0;
2573 FILE *out;
2575 if (!packed_ref_cache->lock)
2576 die("internal error: packed-refs not locked");
2578 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2579 if (!out)
2580 die_errno("unable to fdopen packed-refs descriptor");
2582 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2583 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2584 0, write_packed_entry_fn, out);
2586 if (commit_lock_file(packed_ref_cache->lock)) {
2587 save_errno = errno;
2588 error = -1;
2590 packed_ref_cache->lock = NULL;
2591 release_packed_ref_cache(packed_ref_cache);
2592 errno = save_errno;
2593 return error;
2596 void rollback_packed_refs(void)
2598 struct packed_ref_cache *packed_ref_cache =
2599 get_packed_ref_cache(&ref_cache);
2601 if (!packed_ref_cache->lock)
2602 die("internal error: packed-refs not locked");
2603 rollback_lock_file(packed_ref_cache->lock);
2604 packed_ref_cache->lock = NULL;
2605 release_packed_ref_cache(packed_ref_cache);
2606 clear_packed_ref_cache(&ref_cache);
2609 struct ref_to_prune {
2610 struct ref_to_prune *next;
2611 unsigned char sha1[20];
2612 char name[FLEX_ARRAY];
2615 struct pack_refs_cb_data {
2616 unsigned int flags;
2617 struct ref_dir *packed_refs;
2618 struct ref_to_prune *ref_to_prune;
2622 * An each_ref_entry_fn that is run over loose references only. If
2623 * the loose reference can be packed, add an entry in the packed ref
2624 * cache. If the reference should be pruned, also add it to
2625 * ref_to_prune in the pack_refs_cb_data.
2627 static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2629 struct pack_refs_cb_data *cb = cb_data;
2630 enum peel_status peel_status;
2631 struct ref_entry *packed_entry;
2632 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2634 /* ALWAYS pack tags */
2635 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2636 return 0;
2638 /* Do not pack symbolic or broken refs: */
2639 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2640 return 0;
2642 /* Add a packed ref cache entry equivalent to the loose entry. */
2643 peel_status = peel_entry(entry, 1);
2644 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2645 die("internal error peeling reference %s (%s)",
2646 entry->name, oid_to_hex(&entry->u.value.oid));
2647 packed_entry = find_ref(cb->packed_refs, entry->name);
2648 if (packed_entry) {
2649 /* Overwrite existing packed entry with info from loose entry */
2650 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2651 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2652 } else {
2653 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2654 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2655 add_ref(cb->packed_refs, packed_entry);
2657 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2659 /* Schedule the loose reference for pruning if requested. */
2660 if ((cb->flags & PACK_REFS_PRUNE)) {
2661 int namelen = strlen(entry->name) + 1;
2662 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2663 hashcpy(n->sha1, entry->u.value.oid.hash);
2664 strcpy(n->name, entry->name);
2665 n->next = cb->ref_to_prune;
2666 cb->ref_to_prune = n;
2668 return 0;
2672 * Remove empty parents, but spare refs/ and immediate subdirs.
2673 * Note: munges *name.
2675 static void try_remove_empty_parents(char *name)
2677 char *p, *q;
2678 int i;
2679 p = name;
2680 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2681 while (*p && *p != '/')
2682 p++;
2683 /* tolerate duplicate slashes; see check_refname_format() */
2684 while (*p == '/')
2685 p++;
2687 for (q = p; *q; q++)
2689 while (1) {
2690 while (q > p && *q != '/')
2691 q--;
2692 while (q > p && *(q-1) == '/')
2693 q--;
2694 if (q == p)
2695 break;
2696 *q = '\0';
2697 if (rmdir(git_path("%s", name)))
2698 break;
2702 /* make sure nobody touched the ref, and unlink */
2703 static void prune_ref(struct ref_to_prune *r)
2705 struct ref_transaction *transaction;
2706 struct strbuf err = STRBUF_INIT;
2708 if (check_refname_format(r->name, 0))
2709 return;
2711 transaction = ref_transaction_begin(&err);
2712 if (!transaction ||
2713 ref_transaction_delete(transaction, r->name, r->sha1,
2714 REF_ISPRUNING, NULL, &err) ||
2715 ref_transaction_commit(transaction, &err)) {
2716 ref_transaction_free(transaction);
2717 error("%s", err.buf);
2718 strbuf_release(&err);
2719 return;
2721 ref_transaction_free(transaction);
2722 strbuf_release(&err);
2723 try_remove_empty_parents(r->name);
2726 static void prune_refs(struct ref_to_prune *r)
2728 while (r) {
2729 prune_ref(r);
2730 r = r->next;
2734 int pack_refs(unsigned int flags)
2736 struct pack_refs_cb_data cbdata;
2738 memset(&cbdata, 0, sizeof(cbdata));
2739 cbdata.flags = flags;
2741 lock_packed_refs(LOCK_DIE_ON_ERROR);
2742 cbdata.packed_refs = get_packed_refs(&ref_cache);
2744 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2745 pack_if_possible_fn, &cbdata);
2747 if (commit_packed_refs())
2748 die_errno("unable to overwrite old ref-pack file");
2750 prune_refs(cbdata.ref_to_prune);
2751 return 0;
2754 int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2756 struct ref_dir *packed;
2757 struct string_list_item *refname;
2758 int ret, needs_repacking = 0, removed = 0;
2760 assert(err);
2762 /* Look for a packed ref */
2763 for_each_string_list_item(refname, refnames) {
2764 if (get_packed_ref(refname->string)) {
2765 needs_repacking = 1;
2766 break;
2770 /* Avoid locking if we have nothing to do */
2771 if (!needs_repacking)
2772 return 0; /* no refname exists in packed refs */
2774 if (lock_packed_refs(0)) {
2775 unable_to_lock_message(git_path("packed-refs"), errno, err);
2776 return -1;
2778 packed = get_packed_refs(&ref_cache);
2780 /* Remove refnames from the cache */
2781 for_each_string_list_item(refname, refnames)
2782 if (remove_entry(packed, refname->string) != -1)
2783 removed = 1;
2784 if (!removed) {
2786 * All packed entries disappeared while we were
2787 * acquiring the lock.
2789 rollback_packed_refs();
2790 return 0;
2793 /* Write what remains */
2794 ret = commit_packed_refs();
2795 if (ret)
2796 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2797 strerror(errno));
2798 return ret;
2801 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2803 assert(err);
2805 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2807 * loose. The loose file name is the same as the
2808 * lockfile name, minus ".lock":
2810 char *loose_filename = get_locked_file_path(lock->lk);
2811 int res = unlink_or_msg(loose_filename, err);
2812 free(loose_filename);
2813 if (res)
2814 return 1;
2816 return 0;
2819 int delete_ref(const char *refname, const unsigned char *sha1, unsigned int flags)
2821 struct ref_transaction *transaction;
2822 struct strbuf err = STRBUF_INIT;
2824 transaction = ref_transaction_begin(&err);
2825 if (!transaction ||
2826 ref_transaction_delete(transaction, refname,
2827 (sha1 && !is_null_sha1(sha1)) ? sha1 : NULL,
2828 flags, NULL, &err) ||
2829 ref_transaction_commit(transaction, &err)) {
2830 error("%s", err.buf);
2831 ref_transaction_free(transaction);
2832 strbuf_release(&err);
2833 return 1;
2835 ref_transaction_free(transaction);
2836 strbuf_release(&err);
2837 return 0;
2841 * People using contrib's git-new-workdir have .git/logs/refs ->
2842 * /some/other/path/.git/logs/refs, and that may live on another device.
2844 * IOW, to avoid cross device rename errors, the temporary renamed log must
2845 * live into logs/refs.
2847 #define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2849 static int rename_tmp_log(const char *newrefname)
2851 int attempts_remaining = 4;
2853 retry:
2854 switch (safe_create_leading_directories_const(git_path("logs/%s", newrefname))) {
2855 case SCLD_OK:
2856 break; /* success */
2857 case SCLD_VANISHED:
2858 if (--attempts_remaining > 0)
2859 goto retry;
2860 /* fall through */
2861 default:
2862 error("unable to create directory for %s", newrefname);
2863 return -1;
2866 if (rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
2867 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2869 * rename(a, b) when b is an existing
2870 * directory ought to result in ISDIR, but
2871 * Solaris 5.8 gives ENOTDIR. Sheesh.
2873 if (remove_empty_directories(git_path("logs/%s", newrefname))) {
2874 error("Directory not empty: logs/%s", newrefname);
2875 return -1;
2877 goto retry;
2878 } else if (errno == ENOENT && --attempts_remaining > 0) {
2880 * Maybe another process just deleted one of
2881 * the directories in the path to newrefname.
2882 * Try again from the beginning.
2884 goto retry;
2885 } else {
2886 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2887 newrefname, strerror(errno));
2888 return -1;
2891 return 0;
2894 static int rename_ref_available(const char *oldname, const char *newname)
2896 struct string_list skip = STRING_LIST_INIT_NODUP;
2897 struct strbuf err = STRBUF_INIT;
2898 int ret;
2900 string_list_insert(&skip, oldname);
2901 ret = !verify_refname_available(newname, NULL, &skip,
2902 get_packed_refs(&ref_cache), &err)
2903 && !verify_refname_available(newname, NULL, &skip,
2904 get_loose_refs(&ref_cache), &err);
2905 if (!ret)
2906 error("%s", err.buf);
2908 string_list_clear(&skip, 0);
2909 strbuf_release(&err);
2910 return ret;
2913 static int write_ref_to_lockfile(struct ref_lock *lock, const unsigned char *sha1);
2914 static int commit_ref_update(struct ref_lock *lock,
2915 const unsigned char *sha1, const char *logmsg);
2917 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2919 unsigned char sha1[20], orig_sha1[20];
2920 int flag = 0, logmoved = 0;
2921 struct ref_lock *lock;
2922 struct stat loginfo;
2923 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
2924 const char *symref = NULL;
2925 struct strbuf err = STRBUF_INIT;
2927 if (log && S_ISLNK(loginfo.st_mode))
2928 return error("reflog for %s is a symlink", oldrefname);
2930 symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
2931 orig_sha1, &flag);
2932 if (flag & REF_ISSYMREF)
2933 return error("refname %s is a symbolic ref, renaming it is not supported",
2934 oldrefname);
2935 if (!symref)
2936 return error("refname %s not found", oldrefname);
2938 if (!rename_ref_available(oldrefname, newrefname))
2939 return 1;
2941 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2942 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2943 oldrefname, strerror(errno));
2945 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2946 error("unable to delete old %s", oldrefname);
2947 goto rollback;
2950 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
2951 delete_ref(newrefname, sha1, REF_NODEREF)) {
2952 if (errno==EISDIR) {
2953 if (remove_empty_directories(git_path("%s", newrefname))) {
2954 error("Directory not empty: %s", newrefname);
2955 goto rollback;
2957 } else {
2958 error("unable to delete existing %s", newrefname);
2959 goto rollback;
2963 if (log && rename_tmp_log(newrefname))
2964 goto rollback;
2966 logmoved = log;
2968 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);
2969 if (!lock) {
2970 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2971 strbuf_release(&err);
2972 goto rollback;
2974 hashcpy(lock->old_oid.hash, orig_sha1);
2976 if (write_ref_to_lockfile(lock, orig_sha1) ||
2977 commit_ref_update(lock, orig_sha1, logmsg)) {
2978 error("unable to write current sha1 into %s", newrefname);
2979 goto rollback;
2982 return 0;
2984 rollback:
2985 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);
2986 if (!lock) {
2987 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2988 strbuf_release(&err);
2989 goto rollbacklog;
2992 flag = log_all_ref_updates;
2993 log_all_ref_updates = 0;
2994 if (write_ref_to_lockfile(lock, orig_sha1) ||
2995 commit_ref_update(lock, orig_sha1, NULL))
2996 error("unable to write current sha1 into %s", oldrefname);
2997 log_all_ref_updates = flag;
2999 rollbacklog:
3000 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
3001 error("unable to restore logfile %s from %s: %s",
3002 oldrefname, newrefname, strerror(errno));
3003 if (!logmoved && log &&
3004 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
3005 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
3006 oldrefname, strerror(errno));
3008 return 1;
3011 static int close_ref(struct ref_lock *lock)
3013 if (close_lock_file(lock->lk))
3014 return -1;
3015 return 0;
3018 static int commit_ref(struct ref_lock *lock)
3020 if (commit_lock_file(lock->lk))
3021 return -1;
3022 return 0;
3026 * copy the reflog message msg to buf, which has been allocated sufficiently
3027 * large, while cleaning up the whitespaces. Especially, convert LF to space,
3028 * because reflog file is one line per entry.
3030 static int copy_msg(char *buf, const char *msg)
3032 char *cp = buf;
3033 char c;
3034 int wasspace = 1;
3036 *cp++ = '\t';
3037 while ((c = *msg++)) {
3038 if (wasspace && isspace(c))
3039 continue;
3040 wasspace = isspace(c);
3041 if (wasspace)
3042 c = ' ';
3043 *cp++ = c;
3045 while (buf < cp && isspace(cp[-1]))
3046 cp--;
3047 *cp++ = '\n';
3048 return cp - buf;
3051 /* This function must set a meaningful errno on failure */
3052 int log_ref_setup(const char *refname, struct strbuf *sb_logfile)
3054 int logfd, oflags = O_APPEND | O_WRONLY;
3055 char *logfile;
3057 strbuf_git_path(sb_logfile, "logs/%s", refname);
3058 logfile = sb_logfile->buf;
3059 /* make sure the rest of the function can't change "logfile" */
3060 sb_logfile = NULL;
3061 if (log_all_ref_updates &&
3062 (starts_with(refname, "refs/heads/") ||
3063 starts_with(refname, "refs/remotes/") ||
3064 starts_with(refname, "refs/notes/") ||
3065 !strcmp(refname, "HEAD"))) {
3066 if (safe_create_leading_directories(logfile) < 0) {
3067 int save_errno = errno;
3068 error("unable to create directory for %s", logfile);
3069 errno = save_errno;
3070 return -1;
3072 oflags |= O_CREAT;
3075 logfd = open(logfile, oflags, 0666);
3076 if (logfd < 0) {
3077 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
3078 return 0;
3080 if (errno == EISDIR) {
3081 if (remove_empty_directories(logfile)) {
3082 int save_errno = errno;
3083 error("There are still logs under '%s'",
3084 logfile);
3085 errno = save_errno;
3086 return -1;
3088 logfd = open(logfile, oflags, 0666);
3091 if (logfd < 0) {
3092 int save_errno = errno;
3093 error("Unable to append to %s: %s", logfile,
3094 strerror(errno));
3095 errno = save_errno;
3096 return -1;
3100 adjust_shared_perm(logfile);
3101 close(logfd);
3102 return 0;
3105 static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
3106 const unsigned char *new_sha1,
3107 const char *committer, const char *msg)
3109 int msglen, written;
3110 unsigned maxlen, len;
3111 char *logrec;
3113 msglen = msg ? strlen(msg) : 0;
3114 maxlen = strlen(committer) + msglen + 100;
3115 logrec = xmalloc(maxlen);
3116 len = sprintf(logrec, "%s %s %s\n",
3117 sha1_to_hex(old_sha1),
3118 sha1_to_hex(new_sha1),
3119 committer);
3120 if (msglen)
3121 len += copy_msg(logrec + len - 1, msg) - 1;
3123 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
3124 free(logrec);
3125 if (written != len)
3126 return -1;
3128 return 0;
3131 static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
3132 const unsigned char *new_sha1, const char *msg,
3133 struct strbuf *sb_log_file)
3135 int logfd, result, oflags = O_APPEND | O_WRONLY;
3136 char *log_file;
3138 if (log_all_ref_updates < 0)
3139 log_all_ref_updates = !is_bare_repository();
3141 result = log_ref_setup(refname, sb_log_file);
3142 if (result)
3143 return result;
3144 log_file = sb_log_file->buf;
3145 /* make sure the rest of the function can't change "log_file" */
3146 sb_log_file = NULL;
3148 logfd = open(log_file, oflags);
3149 if (logfd < 0)
3150 return 0;
3151 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
3152 git_committer_info(0), msg);
3153 if (result) {
3154 int save_errno = errno;
3155 close(logfd);
3156 error("Unable to append to %s", log_file);
3157 errno = save_errno;
3158 return -1;
3160 if (close(logfd)) {
3161 int save_errno = errno;
3162 error("Unable to append to %s", log_file);
3163 errno = save_errno;
3164 return -1;
3166 return 0;
3169 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
3170 const unsigned char *new_sha1, const char *msg)
3172 struct strbuf sb = STRBUF_INIT;
3173 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb);
3174 strbuf_release(&sb);
3175 return ret;
3178 int is_branch(const char *refname)
3180 return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
3184 * Write sha1 into the open lockfile, then close the lockfile. On
3185 * errors, rollback the lockfile and set errno to reflect the problem.
3187 static int write_ref_to_lockfile(struct ref_lock *lock,
3188 const unsigned char *sha1)
3190 static char term = '\n';
3191 struct object *o;
3193 o = parse_object(sha1);
3194 if (!o) {
3195 error("Trying to write ref %s with nonexistent object %s",
3196 lock->ref_name, sha1_to_hex(sha1));
3197 unlock_ref(lock);
3198 errno = EINVAL;
3199 return -1;
3201 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
3202 error("Trying to write non-commit object %s to branch %s",
3203 sha1_to_hex(sha1), lock->ref_name);
3204 unlock_ref(lock);
3205 errno = EINVAL;
3206 return -1;
3208 if (write_in_full(lock->lk->fd, sha1_to_hex(sha1), 40) != 40 ||
3209 write_in_full(lock->lk->fd, &term, 1) != 1 ||
3210 close_ref(lock) < 0) {
3211 int save_errno = errno;
3212 error("Couldn't write %s", lock->lk->filename.buf);
3213 unlock_ref(lock);
3214 errno = save_errno;
3215 return -1;
3217 return 0;
3221 * Commit a change to a loose reference that has already been written
3222 * to the loose reference lockfile. Also update the reflogs if
3223 * necessary, using the specified lockmsg (which can be NULL).
3225 static int commit_ref_update(struct ref_lock *lock,
3226 const unsigned char *sha1, const char *logmsg)
3228 clear_loose_ref_cache(&ref_cache);
3229 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg) < 0 ||
3230 (strcmp(lock->ref_name, lock->orig_ref_name) &&
3231 log_ref_write(lock->orig_ref_name, lock->old_oid.hash, sha1, logmsg) < 0)) {
3232 unlock_ref(lock);
3233 return -1;
3235 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
3237 * Special hack: If a branch is updated directly and HEAD
3238 * points to it (may happen on the remote side of a push
3239 * for example) then logically the HEAD reflog should be
3240 * updated too.
3241 * A generic solution implies reverse symref information,
3242 * but finding all symrefs pointing to the given branch
3243 * would be rather costly for this rare event (the direct
3244 * update of a branch) to be worth it. So let's cheat and
3245 * check with HEAD only which should cover 99% of all usage
3246 * scenarios (even 100% of the default ones).
3248 unsigned char head_sha1[20];
3249 int head_flag;
3250 const char *head_ref;
3251 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3252 head_sha1, &head_flag);
3253 if (head_ref && (head_flag & REF_ISSYMREF) &&
3254 !strcmp(head_ref, lock->ref_name))
3255 log_ref_write("HEAD", lock->old_oid.hash, sha1, logmsg);
3257 if (commit_ref(lock)) {
3258 error("Couldn't set %s", lock->ref_name);
3259 unlock_ref(lock);
3260 return -1;
3262 unlock_ref(lock);
3263 return 0;
3266 int create_symref(const char *ref_target, const char *refs_heads_master,
3267 const char *logmsg)
3269 const char *lockpath;
3270 char ref[1000];
3271 int fd, len, written;
3272 char *git_HEAD = git_pathdup("%s", ref_target);
3273 unsigned char old_sha1[20], new_sha1[20];
3275 if (logmsg && read_ref(ref_target, old_sha1))
3276 hashclr(old_sha1);
3278 if (safe_create_leading_directories(git_HEAD) < 0)
3279 return error("unable to create directory for %s", git_HEAD);
3281 #ifndef NO_SYMLINK_HEAD
3282 if (prefer_symlink_refs) {
3283 unlink(git_HEAD);
3284 if (!symlink(refs_heads_master, git_HEAD))
3285 goto done;
3286 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
3288 #endif
3290 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
3291 if (sizeof(ref) <= len) {
3292 error("refname too long: %s", refs_heads_master);
3293 goto error_free_return;
3295 lockpath = mkpath("%s.lock", git_HEAD);
3296 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
3297 if (fd < 0) {
3298 error("Unable to open %s for writing", lockpath);
3299 goto error_free_return;
3301 written = write_in_full(fd, ref, len);
3302 if (close(fd) != 0 || written != len) {
3303 error("Unable to write to %s", lockpath);
3304 goto error_unlink_return;
3306 if (rename(lockpath, git_HEAD) < 0) {
3307 error("Unable to create %s", git_HEAD);
3308 goto error_unlink_return;
3310 if (adjust_shared_perm(git_HEAD)) {
3311 error("Unable to fix permissions on %s", lockpath);
3312 error_unlink_return:
3313 unlink_or_warn(lockpath);
3314 error_free_return:
3315 free(git_HEAD);
3316 return -1;
3319 #ifndef NO_SYMLINK_HEAD
3320 done:
3321 #endif
3322 if (logmsg && !read_ref(refs_heads_master, new_sha1))
3323 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
3325 free(git_HEAD);
3326 return 0;
3329 struct read_ref_at_cb {
3330 const char *refname;
3331 unsigned long at_time;
3332 int cnt;
3333 int reccnt;
3334 unsigned char *sha1;
3335 int found_it;
3337 unsigned char osha1[20];
3338 unsigned char nsha1[20];
3339 int tz;
3340 unsigned long date;
3341 char **msg;
3342 unsigned long *cutoff_time;
3343 int *cutoff_tz;
3344 int *cutoff_cnt;
3347 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
3348 const char *email, unsigned long timestamp, int tz,
3349 const char *message, void *cb_data)
3351 struct read_ref_at_cb *cb = cb_data;
3353 cb->reccnt++;
3354 cb->tz = tz;
3355 cb->date = timestamp;
3357 if (timestamp <= cb->at_time || cb->cnt == 0) {
3358 if (cb->msg)
3359 *cb->msg = xstrdup(message);
3360 if (cb->cutoff_time)
3361 *cb->cutoff_time = timestamp;
3362 if (cb->cutoff_tz)
3363 *cb->cutoff_tz = tz;
3364 if (cb->cutoff_cnt)
3365 *cb->cutoff_cnt = cb->reccnt - 1;
3367 * we have not yet updated cb->[n|o]sha1 so they still
3368 * hold the values for the previous record.
3370 if (!is_null_sha1(cb->osha1)) {
3371 hashcpy(cb->sha1, nsha1);
3372 if (hashcmp(cb->osha1, nsha1))
3373 warning("Log for ref %s has gap after %s.",
3374 cb->refname, show_date(cb->date, cb->tz, DATE_RFC2822));
3376 else if (cb->date == cb->at_time)
3377 hashcpy(cb->sha1, nsha1);
3378 else if (hashcmp(nsha1, cb->sha1))
3379 warning("Log for ref %s unexpectedly ended on %s.",
3380 cb->refname, show_date(cb->date, cb->tz,
3381 DATE_RFC2822));
3382 hashcpy(cb->osha1, osha1);
3383 hashcpy(cb->nsha1, nsha1);
3384 cb->found_it = 1;
3385 return 1;
3387 hashcpy(cb->osha1, osha1);
3388 hashcpy(cb->nsha1, nsha1);
3389 if (cb->cnt > 0)
3390 cb->cnt--;
3391 return 0;
3394 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
3395 const char *email, unsigned long timestamp,
3396 int tz, const char *message, void *cb_data)
3398 struct read_ref_at_cb *cb = cb_data;
3400 if (cb->msg)
3401 *cb->msg = xstrdup(message);
3402 if (cb->cutoff_time)
3403 *cb->cutoff_time = timestamp;
3404 if (cb->cutoff_tz)
3405 *cb->cutoff_tz = tz;
3406 if (cb->cutoff_cnt)
3407 *cb->cutoff_cnt = cb->reccnt;
3408 hashcpy(cb->sha1, osha1);
3409 if (is_null_sha1(cb->sha1))
3410 hashcpy(cb->sha1, nsha1);
3411 /* We just want the first entry */
3412 return 1;
3415 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
3416 unsigned char *sha1, char **msg,
3417 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
3419 struct read_ref_at_cb cb;
3421 memset(&cb, 0, sizeof(cb));
3422 cb.refname = refname;
3423 cb.at_time = at_time;
3424 cb.cnt = cnt;
3425 cb.msg = msg;
3426 cb.cutoff_time = cutoff_time;
3427 cb.cutoff_tz = cutoff_tz;
3428 cb.cutoff_cnt = cutoff_cnt;
3429 cb.sha1 = sha1;
3431 for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
3433 if (!cb.reccnt) {
3434 if (flags & GET_SHA1_QUIETLY)
3435 exit(128);
3436 else
3437 die("Log for %s is empty.", refname);
3439 if (cb.found_it)
3440 return 0;
3442 for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
3444 return 1;
3447 int reflog_exists(const char *refname)
3449 struct stat st;
3451 return !lstat(git_path("logs/%s", refname), &st) &&
3452 S_ISREG(st.st_mode);
3455 int delete_reflog(const char *refname)
3457 return remove_path(git_path("logs/%s", refname));
3460 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3462 unsigned char osha1[20], nsha1[20];
3463 char *email_end, *message;
3464 unsigned long timestamp;
3465 int tz;
3467 /* old SP new SP name <email> SP time TAB msg LF */
3468 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3469 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3470 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3471 !(email_end = strchr(sb->buf + 82, '>')) ||
3472 email_end[1] != ' ' ||
3473 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3474 !message || message[0] != ' ' ||
3475 (message[1] != '+' && message[1] != '-') ||
3476 !isdigit(message[2]) || !isdigit(message[3]) ||
3477 !isdigit(message[4]) || !isdigit(message[5]))
3478 return 0; /* corrupt? */
3479 email_end[1] = '\0';
3480 tz = strtol(message + 1, NULL, 10);
3481 if (message[6] != '\t')
3482 message += 6;
3483 else
3484 message += 7;
3485 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3488 static char *find_beginning_of_line(char *bob, char *scan)
3490 while (bob < scan && *(--scan) != '\n')
3491 ; /* keep scanning backwards */
3493 * Return either beginning of the buffer, or LF at the end of
3494 * the previous line.
3496 return scan;
3499 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3501 struct strbuf sb = STRBUF_INIT;
3502 FILE *logfp;
3503 long pos;
3504 int ret = 0, at_tail = 1;
3506 logfp = fopen(git_path("logs/%s", refname), "r");
3507 if (!logfp)
3508 return -1;
3510 /* Jump to the end */
3511 if (fseek(logfp, 0, SEEK_END) < 0)
3512 return error("cannot seek back reflog for %s: %s",
3513 refname, strerror(errno));
3514 pos = ftell(logfp);
3515 while (!ret && 0 < pos) {
3516 int cnt;
3517 size_t nread;
3518 char buf[BUFSIZ];
3519 char *endp, *scanp;
3521 /* Fill next block from the end */
3522 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3523 if (fseek(logfp, pos - cnt, SEEK_SET))
3524 return error("cannot seek back reflog for %s: %s",
3525 refname, strerror(errno));
3526 nread = fread(buf, cnt, 1, logfp);
3527 if (nread != 1)
3528 return error("cannot read %d bytes from reflog for %s: %s",
3529 cnt, refname, strerror(errno));
3530 pos -= cnt;
3532 scanp = endp = buf + cnt;
3533 if (at_tail && scanp[-1] == '\n')
3534 /* Looking at the final LF at the end of the file */
3535 scanp--;
3536 at_tail = 0;
3538 while (buf < scanp) {
3540 * terminating LF of the previous line, or the beginning
3541 * of the buffer.
3543 char *bp;
3545 bp = find_beginning_of_line(buf, scanp);
3547 if (*bp == '\n') {
3549 * The newline is the end of the previous line,
3550 * so we know we have complete line starting
3551 * at (bp + 1). Prefix it onto any prior data
3552 * we collected for the line and process it.
3554 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3555 scanp = bp;
3556 endp = bp + 1;
3557 ret = show_one_reflog_ent(&sb, fn, cb_data);
3558 strbuf_reset(&sb);
3559 if (ret)
3560 break;
3561 } else if (!pos) {
3563 * We are at the start of the buffer, and the
3564 * start of the file; there is no previous
3565 * line, and we have everything for this one.
3566 * Process it, and we can end the loop.
3568 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3569 ret = show_one_reflog_ent(&sb, fn, cb_data);
3570 strbuf_reset(&sb);
3571 break;
3574 if (bp == buf) {
3576 * We are at the start of the buffer, and there
3577 * is more file to read backwards. Which means
3578 * we are in the middle of a line. Note that we
3579 * may get here even if *bp was a newline; that
3580 * just means we are at the exact end of the
3581 * previous line, rather than some spot in the
3582 * middle.
3584 * Save away what we have to be combined with
3585 * the data from the next read.
3587 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3588 break;
3593 if (!ret && sb.len)
3594 die("BUG: reverse reflog parser had leftover data");
3596 fclose(logfp);
3597 strbuf_release(&sb);
3598 return ret;
3601 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3603 FILE *logfp;
3604 struct strbuf sb = STRBUF_INIT;
3605 int ret = 0;
3607 logfp = fopen(git_path("logs/%s", refname), "r");
3608 if (!logfp)
3609 return -1;
3611 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3612 ret = show_one_reflog_ent(&sb, fn, cb_data);
3613 fclose(logfp);
3614 strbuf_release(&sb);
3615 return ret;
3618 * Call fn for each reflog in the namespace indicated by name. name
3619 * must be empty or end with '/'. Name will be used as a scratch
3620 * space, but its contents will be restored before return.
3622 static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3624 DIR *d = opendir(git_path("logs/%s", name->buf));
3625 int retval = 0;
3626 struct dirent *de;
3627 int oldlen = name->len;
3629 if (!d)
3630 return name->len ? errno : 0;
3632 while ((de = readdir(d)) != NULL) {
3633 struct stat st;
3635 if (de->d_name[0] == '.')
3636 continue;
3637 if (ends_with(de->d_name, ".lock"))
3638 continue;
3639 strbuf_addstr(name, de->d_name);
3640 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3641 ; /* silently ignore */
3642 } else {
3643 if (S_ISDIR(st.st_mode)) {
3644 strbuf_addch(name, '/');
3645 retval = do_for_each_reflog(name, fn, cb_data);
3646 } else {
3647 struct object_id oid;
3649 if (read_ref_full(name->buf, 0, oid.hash, NULL))
3650 retval = error("bad ref for %s", name->buf);
3651 else
3652 retval = fn(name->buf, &oid, 0, cb_data);
3654 if (retval)
3655 break;
3657 strbuf_setlen(name, oldlen);
3659 closedir(d);
3660 return retval;
3663 int for_each_reflog(each_ref_fn fn, void *cb_data)
3665 int retval;
3666 struct strbuf name;
3667 strbuf_init(&name, PATH_MAX);
3668 retval = do_for_each_reflog(&name, fn, cb_data);
3669 strbuf_release(&name);
3670 return retval;
3674 * Information needed for a single ref update. Set new_sha1 to the new
3675 * value or to null_sha1 to delete the ref. To check the old value
3676 * while the ref is locked, set (flags & REF_HAVE_OLD) and set
3677 * old_sha1 to the old value, or to null_sha1 to ensure the ref does
3678 * not exist before update.
3680 struct ref_update {
3682 * If (flags & REF_HAVE_NEW), set the reference to this value:
3684 unsigned char new_sha1[20];
3686 * If (flags & REF_HAVE_OLD), check that the reference
3687 * previously had this value:
3689 unsigned char old_sha1[20];
3691 * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
3692 * REF_DELETING, and REF_ISPRUNING:
3694 unsigned int flags;
3695 struct ref_lock *lock;
3696 int type;
3697 char *msg;
3698 const char refname[FLEX_ARRAY];
3702 * Transaction states.
3703 * OPEN: The transaction is in a valid state and can accept new updates.
3704 * An OPEN transaction can be committed.
3705 * CLOSED: A closed transaction is no longer active and no other operations
3706 * than free can be used on it in this state.
3707 * A transaction can either become closed by successfully committing
3708 * an active transaction or if there is a failure while building
3709 * the transaction thus rendering it failed/inactive.
3711 enum ref_transaction_state {
3712 REF_TRANSACTION_OPEN = 0,
3713 REF_TRANSACTION_CLOSED = 1
3717 * Data structure for holding a reference transaction, which can
3718 * consist of checks and updates to multiple references, carried out
3719 * as atomically as possible. This structure is opaque to callers.
3721 struct ref_transaction {
3722 struct ref_update **updates;
3723 size_t alloc;
3724 size_t nr;
3725 enum ref_transaction_state state;
3728 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
3730 assert(err);
3732 return xcalloc(1, sizeof(struct ref_transaction));
3735 void ref_transaction_free(struct ref_transaction *transaction)
3737 int i;
3739 if (!transaction)
3740 return;
3742 for (i = 0; i < transaction->nr; i++) {
3743 free(transaction->updates[i]->msg);
3744 free(transaction->updates[i]);
3746 free(transaction->updates);
3747 free(transaction);
3750 static struct ref_update *add_update(struct ref_transaction *transaction,
3751 const char *refname)
3753 size_t len = strlen(refname);
3754 struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
3756 strcpy((char *)update->refname, refname);
3757 ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
3758 transaction->updates[transaction->nr++] = update;
3759 return update;
3762 int ref_transaction_update(struct ref_transaction *transaction,
3763 const char *refname,
3764 const unsigned char *new_sha1,
3765 const unsigned char *old_sha1,
3766 unsigned int flags, const char *msg,
3767 struct strbuf *err)
3769 struct ref_update *update;
3771 assert(err);
3773 if (transaction->state != REF_TRANSACTION_OPEN)
3774 die("BUG: update called for transaction that is not open");
3776 if (new_sha1 && !is_null_sha1(new_sha1) &&
3777 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
3778 strbuf_addf(err, "refusing to update ref with bad name %s",
3779 refname);
3780 return -1;
3783 update = add_update(transaction, refname);
3784 if (new_sha1) {
3785 hashcpy(update->new_sha1, new_sha1);
3786 flags |= REF_HAVE_NEW;
3788 if (old_sha1) {
3789 hashcpy(update->old_sha1, old_sha1);
3790 flags |= REF_HAVE_OLD;
3792 update->flags = flags;
3793 if (msg)
3794 update->msg = xstrdup(msg);
3795 return 0;
3798 int ref_transaction_create(struct ref_transaction *transaction,
3799 const char *refname,
3800 const unsigned char *new_sha1,
3801 unsigned int flags, const char *msg,
3802 struct strbuf *err)
3804 if (!new_sha1 || is_null_sha1(new_sha1))
3805 die("BUG: create called without valid new_sha1");
3806 return ref_transaction_update(transaction, refname, new_sha1,
3807 null_sha1, flags, msg, err);
3810 int ref_transaction_delete(struct ref_transaction *transaction,
3811 const char *refname,
3812 const unsigned char *old_sha1,
3813 unsigned int flags, const char *msg,
3814 struct strbuf *err)
3816 if (old_sha1 && is_null_sha1(old_sha1))
3817 die("BUG: delete called with old_sha1 set to zeros");
3818 return ref_transaction_update(transaction, refname,
3819 null_sha1, old_sha1,
3820 flags, msg, err);
3823 int ref_transaction_verify(struct ref_transaction *transaction,
3824 const char *refname,
3825 const unsigned char *old_sha1,
3826 unsigned int flags,
3827 struct strbuf *err)
3829 if (!old_sha1)
3830 die("BUG: verify called with old_sha1 set to NULL");
3831 return ref_transaction_update(transaction, refname,
3832 NULL, old_sha1,
3833 flags, NULL, err);
3836 int update_ref(const char *msg, const char *refname,
3837 const unsigned char *new_sha1, const unsigned char *old_sha1,
3838 unsigned int flags, enum action_on_err onerr)
3840 struct ref_transaction *t;
3841 struct strbuf err = STRBUF_INIT;
3843 t = ref_transaction_begin(&err);
3844 if (!t ||
3845 ref_transaction_update(t, refname, new_sha1, old_sha1,
3846 flags, msg, &err) ||
3847 ref_transaction_commit(t, &err)) {
3848 const char *str = "update_ref failed for ref '%s': %s";
3850 ref_transaction_free(t);
3851 switch (onerr) {
3852 case UPDATE_REFS_MSG_ON_ERR:
3853 error(str, refname, err.buf);
3854 break;
3855 case UPDATE_REFS_DIE_ON_ERR:
3856 die(str, refname, err.buf);
3857 break;
3858 case UPDATE_REFS_QUIET_ON_ERR:
3859 break;
3861 strbuf_release(&err);
3862 return 1;
3864 strbuf_release(&err);
3865 ref_transaction_free(t);
3866 return 0;
3869 static int ref_update_reject_duplicates(struct string_list *refnames,
3870 struct strbuf *err)
3872 int i, n = refnames->nr;
3874 assert(err);
3876 for (i = 1; i < n; i++)
3877 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3878 strbuf_addf(err,
3879 "Multiple updates for ref '%s' not allowed.",
3880 refnames->items[i].string);
3881 return 1;
3883 return 0;
3886 int ref_transaction_commit(struct ref_transaction *transaction,
3887 struct strbuf *err)
3889 int ret = 0, i;
3890 int n = transaction->nr;
3891 struct ref_update **updates = transaction->updates;
3892 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3893 struct string_list_item *ref_to_delete;
3894 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
3896 assert(err);
3898 if (transaction->state != REF_TRANSACTION_OPEN)
3899 die("BUG: commit called for transaction that is not open");
3901 if (!n) {
3902 transaction->state = REF_TRANSACTION_CLOSED;
3903 return 0;
3906 /* Fail if a refname appears more than once in the transaction: */
3907 for (i = 0; i < n; i++)
3908 string_list_append(&affected_refnames, updates[i]->refname);
3909 string_list_sort(&affected_refnames);
3910 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3911 ret = TRANSACTION_GENERIC_ERROR;
3912 goto cleanup;
3916 * Acquire all locks, verify old values if provided, check
3917 * that new values are valid, and write new values to the
3918 * lockfiles, ready to be activated. Only keep one lockfile
3919 * open at a time to avoid running out of file descriptors.
3921 for (i = 0; i < n; i++) {
3922 struct ref_update *update = updates[i];
3924 if ((update->flags & REF_HAVE_NEW) &&
3925 is_null_sha1(update->new_sha1))
3926 update->flags |= REF_DELETING;
3927 update->lock = lock_ref_sha1_basic(
3928 update->refname,
3929 ((update->flags & REF_HAVE_OLD) ?
3930 update->old_sha1 : NULL),
3931 &affected_refnames, NULL,
3932 update->flags,
3933 &update->type,
3934 err);
3935 if (!update->lock) {
3936 char *reason;
3938 ret = (errno == ENOTDIR)
3939 ? TRANSACTION_NAME_CONFLICT
3940 : TRANSACTION_GENERIC_ERROR;
3941 reason = strbuf_detach(err, NULL);
3942 strbuf_addf(err, "cannot lock ref '%s': %s",
3943 update->refname, reason);
3944 free(reason);
3945 goto cleanup;
3947 if ((update->flags & REF_HAVE_NEW) &&
3948 !(update->flags & REF_DELETING)) {
3949 int overwriting_symref = ((update->type & REF_ISSYMREF) &&
3950 (update->flags & REF_NODEREF));
3952 if (!overwriting_symref &&
3953 !hashcmp(update->lock->old_oid.hash, update->new_sha1)) {
3955 * The reference already has the desired
3956 * value, so we don't need to write it.
3958 } else if (write_ref_to_lockfile(update->lock,
3959 update->new_sha1)) {
3961 * The lock was freed upon failure of
3962 * write_ref_to_lockfile():
3964 update->lock = NULL;
3965 strbuf_addf(err, "cannot update the ref '%s'.",
3966 update->refname);
3967 ret = TRANSACTION_GENERIC_ERROR;
3968 goto cleanup;
3969 } else {
3970 update->flags |= REF_NEEDS_COMMIT;
3973 if (!(update->flags & REF_NEEDS_COMMIT)) {
3975 * We didn't have to write anything to the lockfile.
3976 * Close it to free up the file descriptor:
3978 if (close_ref(update->lock)) {
3979 strbuf_addf(err, "Couldn't close %s.lock",
3980 update->refname);
3981 goto cleanup;
3986 /* Perform updates first so live commits remain referenced */
3987 for (i = 0; i < n; i++) {
3988 struct ref_update *update = updates[i];
3990 if (update->flags & REF_NEEDS_COMMIT) {
3991 if (commit_ref_update(update->lock,
3992 update->new_sha1, update->msg)) {
3993 /* freed by commit_ref_update(): */
3994 update->lock = NULL;
3995 strbuf_addf(err, "Cannot update the ref '%s'.",
3996 update->refname);
3997 ret = TRANSACTION_GENERIC_ERROR;
3998 goto cleanup;
3999 } else {
4000 /* freed by commit_ref_update(): */
4001 update->lock = NULL;
4006 /* Perform deletes now that updates are safely completed */
4007 for (i = 0; i < n; i++) {
4008 struct ref_update *update = updates[i];
4010 if (update->flags & REF_DELETING) {
4011 if (delete_ref_loose(update->lock, update->type, err)) {
4012 ret = TRANSACTION_GENERIC_ERROR;
4013 goto cleanup;
4016 if (!(update->flags & REF_ISPRUNING))
4017 string_list_append(&refs_to_delete,
4018 update->lock->ref_name);
4022 if (repack_without_refs(&refs_to_delete, err)) {
4023 ret = TRANSACTION_GENERIC_ERROR;
4024 goto cleanup;
4026 for_each_string_list_item(ref_to_delete, &refs_to_delete)
4027 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
4028 clear_loose_ref_cache(&ref_cache);
4030 cleanup:
4031 transaction->state = REF_TRANSACTION_CLOSED;
4033 for (i = 0; i < n; i++)
4034 if (updates[i]->lock)
4035 unlock_ref(updates[i]->lock);
4036 string_list_clear(&refs_to_delete, 0);
4037 string_list_clear(&affected_refnames, 0);
4038 return ret;
4041 char *shorten_unambiguous_ref(const char *refname, int strict)
4043 int i;
4044 static char **scanf_fmts;
4045 static int nr_rules;
4046 char *short_name;
4048 if (!nr_rules) {
4050 * Pre-generate scanf formats from ref_rev_parse_rules[].
4051 * Generate a format suitable for scanf from a
4052 * ref_rev_parse_rules rule by interpolating "%s" at the
4053 * location of the "%.*s".
4055 size_t total_len = 0;
4056 size_t offset = 0;
4058 /* the rule list is NULL terminated, count them first */
4059 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
4060 /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
4061 total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
4063 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
4065 offset = 0;
4066 for (i = 0; i < nr_rules; i++) {
4067 assert(offset < total_len);
4068 scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
4069 offset += snprintf(scanf_fmts[i], total_len - offset,
4070 ref_rev_parse_rules[i], 2, "%s") + 1;
4074 /* bail out if there are no rules */
4075 if (!nr_rules)
4076 return xstrdup(refname);
4078 /* buffer for scanf result, at most refname must fit */
4079 short_name = xstrdup(refname);
4081 /* skip first rule, it will always match */
4082 for (i = nr_rules - 1; i > 0 ; --i) {
4083 int j;
4084 int rules_to_fail = i;
4085 int short_name_len;
4087 if (1 != sscanf(refname, scanf_fmts[i], short_name))
4088 continue;
4090 short_name_len = strlen(short_name);
4093 * in strict mode, all (except the matched one) rules
4094 * must fail to resolve to a valid non-ambiguous ref
4096 if (strict)
4097 rules_to_fail = nr_rules;
4100 * check if the short name resolves to a valid ref,
4101 * but use only rules prior to the matched one
4103 for (j = 0; j < rules_to_fail; j++) {
4104 const char *rule = ref_rev_parse_rules[j];
4105 char refname[PATH_MAX];
4107 /* skip matched rule */
4108 if (i == j)
4109 continue;
4112 * the short name is ambiguous, if it resolves
4113 * (with this previous rule) to a valid ref
4114 * read_ref() returns 0 on success
4116 mksnpath(refname, sizeof(refname),
4117 rule, short_name_len, short_name);
4118 if (ref_exists(refname))
4119 break;
4123 * short name is non-ambiguous if all previous rules
4124 * haven't resolved to a valid ref
4126 if (j == rules_to_fail)
4127 return short_name;
4130 free(short_name);
4131 return xstrdup(refname);
4134 static struct string_list *hide_refs;
4136 int parse_hide_refs_config(const char *var, const char *value, const char *section)
4138 if (!strcmp("transfer.hiderefs", var) ||
4139 /* NEEDSWORK: use parse_config_key() once both are merged */
4140 (starts_with(var, section) && var[strlen(section)] == '.' &&
4141 !strcmp(var + strlen(section), ".hiderefs"))) {
4142 char *ref;
4143 int len;
4145 if (!value)
4146 return config_error_nonbool(var);
4147 ref = xstrdup(value);
4148 len = strlen(ref);
4149 while (len && ref[len - 1] == '/')
4150 ref[--len] = '\0';
4151 if (!hide_refs) {
4152 hide_refs = xcalloc(1, sizeof(*hide_refs));
4153 hide_refs->strdup_strings = 1;
4155 string_list_append(hide_refs, ref);
4157 return 0;
4160 int ref_is_hidden(const char *refname)
4162 struct string_list_item *item;
4164 if (!hide_refs)
4165 return 0;
4166 for_each_string_list_item(item, hide_refs) {
4167 int len;
4168 if (!starts_with(refname, item->string))
4169 continue;
4170 len = strlen(item->string);
4171 if (!refname[len] || refname[len] == '/')
4172 return 1;
4174 return 0;
4177 struct expire_reflog_cb {
4178 unsigned int flags;
4179 reflog_expiry_should_prune_fn *should_prune_fn;
4180 void *policy_cb;
4181 FILE *newlog;
4182 unsigned char last_kept_sha1[20];
4185 static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
4186 const char *email, unsigned long timestamp, int tz,
4187 const char *message, void *cb_data)
4189 struct expire_reflog_cb *cb = cb_data;
4190 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
4192 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
4193 osha1 = cb->last_kept_sha1;
4195 if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,
4196 message, policy_cb)) {
4197 if (!cb->newlog)
4198 printf("would prune %s", message);
4199 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
4200 printf("prune %s", message);
4201 } else {
4202 if (cb->newlog) {
4203 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
4204 sha1_to_hex(osha1), sha1_to_hex(nsha1),
4205 email, timestamp, tz, message);
4206 hashcpy(cb->last_kept_sha1, nsha1);
4208 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
4209 printf("keep %s", message);
4211 return 0;
4214 int reflog_expire(const char *refname, const unsigned char *sha1,
4215 unsigned int flags,
4216 reflog_expiry_prepare_fn prepare_fn,
4217 reflog_expiry_should_prune_fn should_prune_fn,
4218 reflog_expiry_cleanup_fn cleanup_fn,
4219 void *policy_cb_data)
4221 static struct lock_file reflog_lock;
4222 struct expire_reflog_cb cb;
4223 struct ref_lock *lock;
4224 char *log_file;
4225 int status = 0;
4226 int type;
4227 struct strbuf err = STRBUF_INIT;
4229 memset(&cb, 0, sizeof(cb));
4230 cb.flags = flags;
4231 cb.policy_cb = policy_cb_data;
4232 cb.should_prune_fn = should_prune_fn;
4235 * The reflog file is locked by holding the lock on the
4236 * reference itself, plus we might need to update the
4237 * reference if --updateref was specified:
4239 lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, 0, &type, &err);
4240 if (!lock) {
4241 error("cannot lock ref '%s': %s", refname, err.buf);
4242 strbuf_release(&err);
4243 return -1;
4245 if (!reflog_exists(refname)) {
4246 unlock_ref(lock);
4247 return 0;
4250 log_file = git_pathdup("logs/%s", refname);
4251 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
4253 * Even though holding $GIT_DIR/logs/$reflog.lock has
4254 * no locking implications, we use the lock_file
4255 * machinery here anyway because it does a lot of the
4256 * work we need, including cleaning up if the program
4257 * exits unexpectedly.
4259 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
4260 struct strbuf err = STRBUF_INIT;
4261 unable_to_lock_message(log_file, errno, &err);
4262 error("%s", err.buf);
4263 strbuf_release(&err);
4264 goto failure;
4266 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
4267 if (!cb.newlog) {
4268 error("cannot fdopen %s (%s)",
4269 reflog_lock.filename.buf, strerror(errno));
4270 goto failure;
4274 (*prepare_fn)(refname, sha1, cb.policy_cb);
4275 for_each_reflog_ent(refname, expire_reflog_ent, &cb);
4276 (*cleanup_fn)(cb.policy_cb);
4278 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
4280 * It doesn't make sense to adjust a reference pointed
4281 * to by a symbolic ref based on expiring entries in
4282 * the symbolic reference's reflog. Nor can we update
4283 * a reference if there are no remaining reflog
4284 * entries.
4286 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
4287 !(type & REF_ISSYMREF) &&
4288 !is_null_sha1(cb.last_kept_sha1);
4290 if (close_lock_file(&reflog_lock)) {
4291 status |= error("couldn't write %s: %s", log_file,
4292 strerror(errno));
4293 } else if (update &&
4294 (write_in_full(lock->lk->fd,
4295 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
4296 write_str_in_full(lock->lk->fd, "\n") != 1 ||
4297 close_ref(lock) < 0)) {
4298 status |= error("couldn't write %s",
4299 lock->lk->filename.buf);
4300 rollback_lock_file(&reflog_lock);
4301 } else if (commit_lock_file(&reflog_lock)) {
4302 status |= error("unable to commit reflog '%s' (%s)",
4303 log_file, strerror(errno));
4304 } else if (update && commit_ref(lock)) {
4305 status |= error("couldn't set %s", lock->ref_name);
4308 free(log_file);
4309 unlock_ref(lock);
4310 return status;
4312 failure:
4313 rollback_lock_file(&reflog_lock);
4314 free(log_file);
4315 unlock_ref(lock);
4316 return -1;