refs.c: remove_empty_directories can take a strbuf
[git/git.git] / refs.c
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"
8
9 struct ref_lock {
10 char *ref_name;
11 char *orig_ref_name;
12 struct lock_file *lk;
13 struct object_id old_oid;
14 };
15
16 /*
17 * How to handle various characters in refnames:
18 * 0: An acceptable character for refs
19 * 1: End-of-component
20 * 2: ., look for a preceding . to reject .. in refs
21 * 3: {, look for a preceding @ to reject @{ in refs
22 * 4: A bad character: ASCII control characters, and
23 * ":", "?", "[", "\", "^", "~", SP, or TAB
24 * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
25 */
26 static unsigned char refname_disposition[256] = {
27 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
28 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
29 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
30 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
31 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
32 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
33 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
34 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
35 };
36
37 /*
38 * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
39 * refs (i.e., because the reference is about to be deleted anyway).
40 */
41 #define REF_DELETING 0x02
42
43 /*
44 * Used as a flag in ref_update::flags when a loose ref is being
45 * pruned.
46 */
47 #define REF_ISPRUNING 0x04
48
49 /*
50 * Used as a flag in ref_update::flags when the reference should be
51 * updated to new_sha1.
52 */
53 #define REF_HAVE_NEW 0x08
54
55 /*
56 * Used as a flag in ref_update::flags when old_sha1 should be
57 * checked.
58 */
59 #define REF_HAVE_OLD 0x10
60
61 /*
62 * Used as a flag in ref_update::flags when the lockfile needs to be
63 * committed.
64 */
65 #define REF_NEEDS_COMMIT 0x20
66
67 /*
68 * 0x40 is REF_FORCE_CREATE_REFLOG, so skip it if you're adding a
69 * value to ref_update::flags
70 */
71
72 /*
73 * Try to read one refname component from the front of refname.
74 * Return the length of the component found, or -1 if the component is
75 * not legal. It is legal if it is something reasonable to have under
76 * ".git/refs/"; We do not like it if:
77 *
78 * - any path component of it begins with ".", or
79 * - it has double dots "..", or
80 * - it has ASCII control characters, or
81 * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
82 * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
83 * - it ends with a "/", or
84 * - it ends with ".lock", or
85 * - it contains a "@{" portion
86 */
87 static int check_refname_component(const char *refname, int *flags)
88 {
89 const char *cp;
90 char last = '\0';
91
92 for (cp = refname; ; cp++) {
93 int ch = *cp & 255;
94 unsigned char disp = refname_disposition[ch];
95 switch (disp) {
96 case 1:
97 goto out;
98 case 2:
99 if (last == '.')
100 return -1; /* Refname contains "..". */
101 break;
102 case 3:
103 if (last == '@')
104 return -1; /* Refname contains "@{". */
105 break;
106 case 4:
107 return -1;
108 case 5:
109 if (!(*flags & REFNAME_REFSPEC_PATTERN))
110 return -1; /* refspec can't be a pattern */
111
112 /*
113 * Unset the pattern flag so that we only accept
114 * a single asterisk for one side of refspec.
115 */
116 *flags &= ~ REFNAME_REFSPEC_PATTERN;
117 break;
118 }
119 last = ch;
120 }
121 out:
122 if (cp == refname)
123 return 0; /* Component has zero length. */
124 if (refname[0] == '.')
125 return -1; /* Component starts with '.'. */
126 if (cp - refname >= LOCK_SUFFIX_LEN &&
127 !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
128 return -1; /* Refname ends with ".lock". */
129 return cp - refname;
130 }
131
132 int check_refname_format(const char *refname, int flags)
133 {
134 int component_len, component_count = 0;
135
136 if (!strcmp(refname, "@"))
137 /* Refname is a single character '@'. */
138 return -1;
139
140 while (1) {
141 /* We are at the start of a path component. */
142 component_len = check_refname_component(refname, &flags);
143 if (component_len <= 0)
144 return -1;
145
146 component_count++;
147 if (refname[component_len] == '\0')
148 break;
149 /* Skip to next component. */
150 refname += component_len + 1;
151 }
152
153 if (refname[component_len - 1] == '.')
154 return -1; /* Refname ends with '.'. */
155 if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
156 return -1; /* Refname has only one component. */
157 return 0;
158 }
159
160 struct ref_entry;
161
162 /*
163 * Information used (along with the information in ref_entry) to
164 * describe a single cached reference. This data structure only
165 * occurs embedded in a union in struct ref_entry, and only when
166 * (ref_entry->flag & REF_DIR) is zero.
167 */
168 struct ref_value {
169 /*
170 * The name of the object to which this reference resolves
171 * (which may be a tag object). If REF_ISBROKEN, this is
172 * null. If REF_ISSYMREF, then this is the name of the object
173 * referred to by the last reference in the symlink chain.
174 */
175 struct object_id oid;
176
177 /*
178 * If REF_KNOWS_PEELED, then this field holds the peeled value
179 * of this reference, or null if the reference is known not to
180 * be peelable. See the documentation for peel_ref() for an
181 * exact definition of "peelable".
182 */
183 struct object_id peeled;
184 };
185
186 struct ref_cache;
187
188 /*
189 * Information used (along with the information in ref_entry) to
190 * describe a level in the hierarchy of references. This data
191 * structure only occurs embedded in a union in struct ref_entry, and
192 * only when (ref_entry.flag & REF_DIR) is set. In that case,
193 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
194 * in the directory have already been read:
195 *
196 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
197 * or packed references, already read.
198 *
199 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
200 * references that hasn't been read yet (nor has any of its
201 * subdirectories).
202 *
203 * Entries within a directory are stored within a growable array of
204 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
205 * sorted are sorted by their component name in strcmp() order and the
206 * remaining entries are unsorted.
207 *
208 * Loose references are read lazily, one directory at a time. When a
209 * directory of loose references is read, then all of the references
210 * in that directory are stored, and REF_INCOMPLETE stubs are created
211 * for any subdirectories, but the subdirectories themselves are not
212 * read. The reading is triggered by get_ref_dir().
213 */
214 struct ref_dir {
215 int nr, alloc;
216
217 /*
218 * Entries with index 0 <= i < sorted are sorted by name. New
219 * entries are appended to the list unsorted, and are sorted
220 * only when required; thus we avoid the need to sort the list
221 * after the addition of every reference.
222 */
223 int sorted;
224
225 /* A pointer to the ref_cache that contains this ref_dir. */
226 struct ref_cache *ref_cache;
227
228 struct ref_entry **entries;
229 };
230
231 /*
232 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
233 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
234 * public values; see refs.h.
235 */
236
237 /*
238 * The field ref_entry->u.value.peeled of this value entry contains
239 * the correct peeled value for the reference, which might be
240 * null_sha1 if the reference is not a tag or if it is broken.
241 */
242 #define REF_KNOWS_PEELED 0x10
243
244 /* ref_entry represents a directory of references */
245 #define REF_DIR 0x20
246
247 /*
248 * Entry has not yet been read from disk (used only for REF_DIR
249 * entries representing loose references)
250 */
251 #define REF_INCOMPLETE 0x40
252
253 /*
254 * A ref_entry represents either a reference or a "subdirectory" of
255 * references.
256 *
257 * Each directory in the reference namespace is represented by a
258 * ref_entry with (flags & REF_DIR) set and containing a subdir member
259 * that holds the entries in that directory that have been read so
260 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
261 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
262 * used for loose reference directories.
263 *
264 * References are represented by a ref_entry with (flags & REF_DIR)
265 * unset and a value member that describes the reference's value. The
266 * flag member is at the ref_entry level, but it is also needed to
267 * interpret the contents of the value field (in other words, a
268 * ref_value object is not very much use without the enclosing
269 * ref_entry).
270 *
271 * Reference names cannot end with slash and directories' names are
272 * always stored with a trailing slash (except for the top-level
273 * directory, which is always denoted by ""). This has two nice
274 * consequences: (1) when the entries in each subdir are sorted
275 * lexicographically by name (as they usually are), the references in
276 * a whole tree can be generated in lexicographic order by traversing
277 * the tree in left-to-right, depth-first order; (2) the names of
278 * references and subdirectories cannot conflict, and therefore the
279 * presence of an empty subdirectory does not block the creation of a
280 * similarly-named reference. (The fact that reference names with the
281 * same leading components can conflict *with each other* is a
282 * separate issue that is regulated by verify_refname_available().)
283 *
284 * Please note that the name field contains the fully-qualified
285 * reference (or subdirectory) name. Space could be saved by only
286 * storing the relative names. But that would require the full names
287 * to be generated on the fly when iterating in do_for_each_ref(), and
288 * would break callback functions, who have always been able to assume
289 * that the name strings that they are passed will not be freed during
290 * the iteration.
291 */
292 struct ref_entry {
293 unsigned char flag; /* ISSYMREF? ISPACKED? */
294 union {
295 struct ref_value value; /* if not (flags&REF_DIR) */
296 struct ref_dir subdir; /* if (flags&REF_DIR) */
297 } u;
298 /*
299 * The full name of the reference (e.g., "refs/heads/master")
300 * or the full name of the directory with a trailing slash
301 * (e.g., "refs/heads/"):
302 */
303 char name[FLEX_ARRAY];
304 };
305
306 static void read_loose_refs(const char *dirname, struct ref_dir *dir);
307
308 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
309 {
310 struct ref_dir *dir;
311 assert(entry->flag & REF_DIR);
312 dir = &entry->u.subdir;
313 if (entry->flag & REF_INCOMPLETE) {
314 read_loose_refs(entry->name, dir);
315 entry->flag &= ~REF_INCOMPLETE;
316 }
317 return dir;
318 }
319
320 /*
321 * Check if a refname is safe.
322 * For refs that start with "refs/" we consider it safe as long they do
323 * not try to resolve to outside of refs/.
324 *
325 * For all other refs we only consider them safe iff they only contain
326 * upper case characters and '_' (like "HEAD" AND "MERGE_HEAD", and not like
327 * "config").
328 */
329 static int refname_is_safe(const char *refname)
330 {
331 if (starts_with(refname, "refs/")) {
332 char *buf;
333 int result;
334
335 buf = xmalloc(strlen(refname) + 1);
336 /*
337 * Does the refname try to escape refs/?
338 * For example: refs/foo/../bar is safe but refs/foo/../../bar
339 * is not.
340 */
341 result = !normalize_path_copy(buf, refname + strlen("refs/"));
342 free(buf);
343 return result;
344 }
345 while (*refname) {
346 if (!isupper(*refname) && *refname != '_')
347 return 0;
348 refname++;
349 }
350 return 1;
351 }
352
353 static struct ref_entry *create_ref_entry(const char *refname,
354 const unsigned char *sha1, int flag,
355 int check_name)
356 {
357 int len;
358 struct ref_entry *ref;
359
360 if (check_name &&
361 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
362 die("Reference has invalid format: '%s'", refname);
363 len = strlen(refname) + 1;
364 ref = xmalloc(sizeof(struct ref_entry) + len);
365 hashcpy(ref->u.value.oid.hash, sha1);
366 oidclr(&ref->u.value.peeled);
367 memcpy(ref->name, refname, len);
368 ref->flag = flag;
369 return ref;
370 }
371
372 static void clear_ref_dir(struct ref_dir *dir);
373
374 static void free_ref_entry(struct ref_entry *entry)
375 {
376 if (entry->flag & REF_DIR) {
377 /*
378 * Do not use get_ref_dir() here, as that might
379 * trigger the reading of loose refs.
380 */
381 clear_ref_dir(&entry->u.subdir);
382 }
383 free(entry);
384 }
385
386 /*
387 * Add a ref_entry to the end of dir (unsorted). Entry is always
388 * stored directly in dir; no recursion into subdirectories is
389 * done.
390 */
391 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
392 {
393 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
394 dir->entries[dir->nr++] = entry;
395 /* optimize for the case that entries are added in order */
396 if (dir->nr == 1 ||
397 (dir->nr == dir->sorted + 1 &&
398 strcmp(dir->entries[dir->nr - 2]->name,
399 dir->entries[dir->nr - 1]->name) < 0))
400 dir->sorted = dir->nr;
401 }
402
403 /*
404 * Clear and free all entries in dir, recursively.
405 */
406 static void clear_ref_dir(struct ref_dir *dir)
407 {
408 int i;
409 for (i = 0; i < dir->nr; i++)
410 free_ref_entry(dir->entries[i]);
411 free(dir->entries);
412 dir->sorted = dir->nr = dir->alloc = 0;
413 dir->entries = NULL;
414 }
415
416 /*
417 * Create a struct ref_entry object for the specified dirname.
418 * dirname is the name of the directory with a trailing slash (e.g.,
419 * "refs/heads/") or "" for the top-level directory.
420 */
421 static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
422 const char *dirname, size_t len,
423 int incomplete)
424 {
425 struct ref_entry *direntry;
426 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
427 memcpy(direntry->name, dirname, len);
428 direntry->name[len] = '\0';
429 direntry->u.subdir.ref_cache = ref_cache;
430 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
431 return direntry;
432 }
433
434 static int ref_entry_cmp(const void *a, const void *b)
435 {
436 struct ref_entry *one = *(struct ref_entry **)a;
437 struct ref_entry *two = *(struct ref_entry **)b;
438 return strcmp(one->name, two->name);
439 }
440
441 static void sort_ref_dir(struct ref_dir *dir);
442
443 struct string_slice {
444 size_t len;
445 const char *str;
446 };
447
448 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
449 {
450 const struct string_slice *key = key_;
451 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
452 int cmp = strncmp(key->str, ent->name, key->len);
453 if (cmp)
454 return cmp;
455 return '\0' - (unsigned char)ent->name[key->len];
456 }
457
458 /*
459 * Return the index of the entry with the given refname from the
460 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
461 * no such entry is found. dir must already be complete.
462 */
463 static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
464 {
465 struct ref_entry **r;
466 struct string_slice key;
467
468 if (refname == NULL || !dir->nr)
469 return -1;
470
471 sort_ref_dir(dir);
472 key.len = len;
473 key.str = refname;
474 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
475 ref_entry_cmp_sslice);
476
477 if (r == NULL)
478 return -1;
479
480 return r - dir->entries;
481 }
482
483 /*
484 * Search for a directory entry directly within dir (without
485 * recursing). Sort dir if necessary. subdirname must be a directory
486 * name (i.e., end in '/'). If mkdir is set, then create the
487 * directory if it is missing; otherwise, return NULL if the desired
488 * directory cannot be found. dir must already be complete.
489 */
490 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
491 const char *subdirname, size_t len,
492 int mkdir)
493 {
494 int entry_index = search_ref_dir(dir, subdirname, len);
495 struct ref_entry *entry;
496 if (entry_index == -1) {
497 if (!mkdir)
498 return NULL;
499 /*
500 * Since dir is complete, the absence of a subdir
501 * means that the subdir really doesn't exist;
502 * therefore, create an empty record for it but mark
503 * the record complete.
504 */
505 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
506 add_entry_to_dir(dir, entry);
507 } else {
508 entry = dir->entries[entry_index];
509 }
510 return get_ref_dir(entry);
511 }
512
513 /*
514 * If refname is a reference name, find the ref_dir within the dir
515 * tree that should hold refname. If refname is a directory name
516 * (i.e., ends in '/'), then return that ref_dir itself. dir must
517 * represent the top-level directory and must already be complete.
518 * Sort ref_dirs and recurse into subdirectories as necessary. If
519 * mkdir is set, then create any missing directories; otherwise,
520 * return NULL if the desired directory cannot be found.
521 */
522 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
523 const char *refname, int mkdir)
524 {
525 const char *slash;
526 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
527 size_t dirnamelen = slash - refname + 1;
528 struct ref_dir *subdir;
529 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
530 if (!subdir) {
531 dir = NULL;
532 break;
533 }
534 dir = subdir;
535 }
536
537 return dir;
538 }
539
540 /*
541 * Find the value entry with the given name in dir, sorting ref_dirs
542 * and recursing into subdirectories as necessary. If the name is not
543 * found or it corresponds to a directory entry, return NULL.
544 */
545 static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
546 {
547 int entry_index;
548 struct ref_entry *entry;
549 dir = find_containing_dir(dir, refname, 0);
550 if (!dir)
551 return NULL;
552 entry_index = search_ref_dir(dir, refname, strlen(refname));
553 if (entry_index == -1)
554 return NULL;
555 entry = dir->entries[entry_index];
556 return (entry->flag & REF_DIR) ? NULL : entry;
557 }
558
559 /*
560 * Remove the entry with the given name from dir, recursing into
561 * subdirectories as necessary. If refname is the name of a directory
562 * (i.e., ends with '/'), then remove the directory and its contents.
563 * If the removal was successful, return the number of entries
564 * remaining in the directory entry that contained the deleted entry.
565 * If the name was not found, return -1. Please note that this
566 * function only deletes the entry from the cache; it does not delete
567 * it from the filesystem or ensure that other cache entries (which
568 * might be symbolic references to the removed entry) are updated.
569 * Nor does it remove any containing dir entries that might be made
570 * empty by the removal. dir must represent the top-level directory
571 * and must already be complete.
572 */
573 static int remove_entry(struct ref_dir *dir, const char *refname)
574 {
575 int refname_len = strlen(refname);
576 int entry_index;
577 struct ref_entry *entry;
578 int is_dir = refname[refname_len - 1] == '/';
579 if (is_dir) {
580 /*
581 * refname represents a reference directory. Remove
582 * the trailing slash; otherwise we will get the
583 * directory *representing* refname rather than the
584 * one *containing* it.
585 */
586 char *dirname = xmemdupz(refname, refname_len - 1);
587 dir = find_containing_dir(dir, dirname, 0);
588 free(dirname);
589 } else {
590 dir = find_containing_dir(dir, refname, 0);
591 }
592 if (!dir)
593 return -1;
594 entry_index = search_ref_dir(dir, refname, refname_len);
595 if (entry_index == -1)
596 return -1;
597 entry = dir->entries[entry_index];
598
599 memmove(&dir->entries[entry_index],
600 &dir->entries[entry_index + 1],
601 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
602 );
603 dir->nr--;
604 if (dir->sorted > entry_index)
605 dir->sorted--;
606 free_ref_entry(entry);
607 return dir->nr;
608 }
609
610 /*
611 * Add a ref_entry to the ref_dir (unsorted), recursing into
612 * subdirectories as necessary. dir must represent the top-level
613 * directory. Return 0 on success.
614 */
615 static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
616 {
617 dir = find_containing_dir(dir, ref->name, 1);
618 if (!dir)
619 return -1;
620 add_entry_to_dir(dir, ref);
621 return 0;
622 }
623
624 /*
625 * Emit a warning and return true iff ref1 and ref2 have the same name
626 * and the same sha1. Die if they have the same name but different
627 * sha1s.
628 */
629 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
630 {
631 if (strcmp(ref1->name, ref2->name))
632 return 0;
633
634 /* Duplicate name; make sure that they don't conflict: */
635
636 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
637 /* This is impossible by construction */
638 die("Reference directory conflict: %s", ref1->name);
639
640 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
641 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
642
643 warning("Duplicated ref: %s", ref1->name);
644 return 1;
645 }
646
647 /*
648 * Sort the entries in dir non-recursively (if they are not already
649 * sorted) and remove any duplicate entries.
650 */
651 static void sort_ref_dir(struct ref_dir *dir)
652 {
653 int i, j;
654 struct ref_entry *last = NULL;
655
656 /*
657 * This check also prevents passing a zero-length array to qsort(),
658 * which is a problem on some platforms.
659 */
660 if (dir->sorted == dir->nr)
661 return;
662
663 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
664
665 /* Remove any duplicates: */
666 for (i = 0, j = 0; j < dir->nr; j++) {
667 struct ref_entry *entry = dir->entries[j];
668 if (last && is_dup_ref(last, entry))
669 free_ref_entry(entry);
670 else
671 last = dir->entries[i++] = entry;
672 }
673 dir->sorted = dir->nr = i;
674 }
675
676 /* Include broken references in a do_for_each_ref*() iteration: */
677 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
678
679 /*
680 * Return true iff the reference described by entry can be resolved to
681 * an object in the database. Emit a warning if the referred-to
682 * object does not exist.
683 */
684 static int ref_resolves_to_object(struct ref_entry *entry)
685 {
686 if (entry->flag & REF_ISBROKEN)
687 return 0;
688 if (!has_sha1_file(entry->u.value.oid.hash)) {
689 error("%s does not point to a valid object!", entry->name);
690 return 0;
691 }
692 return 1;
693 }
694
695 /*
696 * current_ref is a performance hack: when iterating over references
697 * using the for_each_ref*() functions, current_ref is set to the
698 * current reference's entry before calling the callback function. If
699 * the callback function calls peel_ref(), then peel_ref() first
700 * checks whether the reference to be peeled is the current reference
701 * (it usually is) and if so, returns that reference's peeled version
702 * if it is available. This avoids a refname lookup in a common case.
703 */
704 static struct ref_entry *current_ref;
705
706 typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
707
708 struct ref_entry_cb {
709 const char *base;
710 int trim;
711 int flags;
712 each_ref_fn *fn;
713 void *cb_data;
714 };
715
716 /*
717 * Handle one reference in a do_for_each_ref*()-style iteration,
718 * calling an each_ref_fn for each entry.
719 */
720 static int do_one_ref(struct ref_entry *entry, void *cb_data)
721 {
722 struct ref_entry_cb *data = cb_data;
723 struct ref_entry *old_current_ref;
724 int retval;
725
726 if (!starts_with(entry->name, data->base))
727 return 0;
728
729 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
730 !ref_resolves_to_object(entry))
731 return 0;
732
733 /* Store the old value, in case this is a recursive call: */
734 old_current_ref = current_ref;
735 current_ref = entry;
736 retval = data->fn(entry->name + data->trim, &entry->u.value.oid,
737 entry->flag, data->cb_data);
738 current_ref = old_current_ref;
739 return retval;
740 }
741
742 /*
743 * Call fn for each reference in dir that has index in the range
744 * offset <= index < dir->nr. Recurse into subdirectories that are in
745 * that index range, sorting them before iterating. This function
746 * does not sort dir itself; it should be sorted beforehand. fn is
747 * called for all references, including broken ones.
748 */
749 static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
750 each_ref_entry_fn fn, void *cb_data)
751 {
752 int i;
753 assert(dir->sorted == dir->nr);
754 for (i = offset; i < dir->nr; i++) {
755 struct ref_entry *entry = dir->entries[i];
756 int retval;
757 if (entry->flag & REF_DIR) {
758 struct ref_dir *subdir = get_ref_dir(entry);
759 sort_ref_dir(subdir);
760 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
761 } else {
762 retval = fn(entry, cb_data);
763 }
764 if (retval)
765 return retval;
766 }
767 return 0;
768 }
769
770 /*
771 * Call fn for each reference in the union of dir1 and dir2, in order
772 * by refname. Recurse into subdirectories. If a value entry appears
773 * in both dir1 and dir2, then only process the version that is in
774 * dir2. The input dirs must already be sorted, but subdirs will be
775 * sorted as needed. fn is called for all references, including
776 * broken ones.
777 */
778 static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
779 struct ref_dir *dir2,
780 each_ref_entry_fn fn, void *cb_data)
781 {
782 int retval;
783 int i1 = 0, i2 = 0;
784
785 assert(dir1->sorted == dir1->nr);
786 assert(dir2->sorted == dir2->nr);
787 while (1) {
788 struct ref_entry *e1, *e2;
789 int cmp;
790 if (i1 == dir1->nr) {
791 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
792 }
793 if (i2 == dir2->nr) {
794 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
795 }
796 e1 = dir1->entries[i1];
797 e2 = dir2->entries[i2];
798 cmp = strcmp(e1->name, e2->name);
799 if (cmp == 0) {
800 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
801 /* Both are directories; descend them in parallel. */
802 struct ref_dir *subdir1 = get_ref_dir(e1);
803 struct ref_dir *subdir2 = get_ref_dir(e2);
804 sort_ref_dir(subdir1);
805 sort_ref_dir(subdir2);
806 retval = do_for_each_entry_in_dirs(
807 subdir1, subdir2, fn, cb_data);
808 i1++;
809 i2++;
810 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
811 /* Both are references; ignore the one from dir1. */
812 retval = fn(e2, cb_data);
813 i1++;
814 i2++;
815 } else {
816 die("conflict between reference and directory: %s",
817 e1->name);
818 }
819 } else {
820 struct ref_entry *e;
821 if (cmp < 0) {
822 e = e1;
823 i1++;
824 } else {
825 e = e2;
826 i2++;
827 }
828 if (e->flag & REF_DIR) {
829 struct ref_dir *subdir = get_ref_dir(e);
830 sort_ref_dir(subdir);
831 retval = do_for_each_entry_in_dir(
832 subdir, 0, fn, cb_data);
833 } else {
834 retval = fn(e, cb_data);
835 }
836 }
837 if (retval)
838 return retval;
839 }
840 }
841
842 /*
843 * Load all of the refs from the dir into our in-memory cache. The hard work
844 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
845 * through all of the sub-directories. We do not even need to care about
846 * sorting, as traversal order does not matter to us.
847 */
848 static void prime_ref_dir(struct ref_dir *dir)
849 {
850 int i;
851 for (i = 0; i < dir->nr; i++) {
852 struct ref_entry *entry = dir->entries[i];
853 if (entry->flag & REF_DIR)
854 prime_ref_dir(get_ref_dir(entry));
855 }
856 }
857
858 struct nonmatching_ref_data {
859 const struct string_list *skip;
860 const char *conflicting_refname;
861 };
862
863 static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
864 {
865 struct nonmatching_ref_data *data = vdata;
866
867 if (data->skip && string_list_has_string(data->skip, entry->name))
868 return 0;
869
870 data->conflicting_refname = entry->name;
871 return 1;
872 }
873
874 /*
875 * Return 0 if a reference named refname could be created without
876 * conflicting with the name of an existing reference in dir.
877 * Otherwise, return a negative value and write an explanation to err.
878 * If extras is non-NULL, it is a list of additional refnames with
879 * which refname is not allowed to conflict. If skip is non-NULL,
880 * ignore potential conflicts with refs in skip (e.g., because they
881 * are scheduled for deletion in the same operation). Behavior is
882 * undefined if the same name is listed in both extras and skip.
883 *
884 * Two reference names conflict if one of them exactly matches the
885 * leading components of the other; e.g., "refs/foo/bar" conflicts
886 * with both "refs/foo" and with "refs/foo/bar/baz" but not with
887 * "refs/foo/bar" or "refs/foo/barbados".
888 *
889 * extras and skip must be sorted.
890 */
891 static int verify_refname_available(const char *refname,
892 const struct string_list *extras,
893 const struct string_list *skip,
894 struct ref_dir *dir,
895 struct strbuf *err)
896 {
897 const char *slash;
898 int pos;
899 struct strbuf dirname = STRBUF_INIT;
900 int ret = -1;
901
902 /*
903 * For the sake of comments in this function, suppose that
904 * refname is "refs/foo/bar".
905 */
906
907 assert(err);
908
909 strbuf_grow(&dirname, strlen(refname) + 1);
910 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
911 /* Expand dirname to the new prefix, not including the trailing slash: */
912 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
913
914 /*
915 * We are still at a leading dir of the refname (e.g.,
916 * "refs/foo"; if there is a reference with that name,
917 * it is a conflict, *unless* it is in skip.
918 */
919 if (dir) {
920 pos = search_ref_dir(dir, dirname.buf, dirname.len);
921 if (pos >= 0 &&
922 (!skip || !string_list_has_string(skip, dirname.buf))) {
923 /*
924 * We found a reference whose name is
925 * a proper prefix of refname; e.g.,
926 * "refs/foo", and is not in skip.
927 */
928 strbuf_addf(err, "'%s' exists; cannot create '%s'",
929 dirname.buf, refname);
930 goto cleanup;
931 }
932 }
933
934 if (extras && string_list_has_string(extras, dirname.buf) &&
935 (!skip || !string_list_has_string(skip, dirname.buf))) {
936 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
937 refname, dirname.buf);
938 goto cleanup;
939 }
940
941 /*
942 * Otherwise, we can try to continue our search with
943 * the next component. So try to look up the
944 * directory, e.g., "refs/foo/". If we come up empty,
945 * we know there is nothing under this whole prefix,
946 * but even in that case we still have to continue the
947 * search for conflicts with extras.
948 */
949 strbuf_addch(&dirname, '/');
950 if (dir) {
951 pos = search_ref_dir(dir, dirname.buf, dirname.len);
952 if (pos < 0) {
953 /*
954 * There was no directory "refs/foo/",
955 * so there is nothing under this
956 * whole prefix. So there is no need
957 * to continue looking for conflicting
958 * references. But we need to continue
959 * looking for conflicting extras.
960 */
961 dir = NULL;
962 } else {
963 dir = get_ref_dir(dir->entries[pos]);
964 }
965 }
966 }
967
968 /*
969 * We are at the leaf of our refname (e.g., "refs/foo/bar").
970 * There is no point in searching for a reference with that
971 * name, because a refname isn't considered to conflict with
972 * itself. But we still need to check for references whose
973 * names are in the "refs/foo/bar/" namespace, because they
974 * *do* conflict.
975 */
976 strbuf_addstr(&dirname, refname + dirname.len);
977 strbuf_addch(&dirname, '/');
978
979 if (dir) {
980 pos = search_ref_dir(dir, dirname.buf, dirname.len);
981
982 if (pos >= 0) {
983 /*
984 * We found a directory named "$refname/"
985 * (e.g., "refs/foo/bar/"). It is a problem
986 * iff it contains any ref that is not in
987 * "skip".
988 */
989 struct nonmatching_ref_data data;
990
991 data.skip = skip;
992 data.conflicting_refname = NULL;
993 dir = get_ref_dir(dir->entries[pos]);
994 sort_ref_dir(dir);
995 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
996 strbuf_addf(err, "'%s' exists; cannot create '%s'",
997 data.conflicting_refname, refname);
998 goto cleanup;
999 }
1000 }
1001 }
1002
1003 if (extras) {
1004 /*
1005 * Check for entries in extras that start with
1006 * "$refname/". We do that by looking for the place
1007 * where "$refname/" would be inserted in extras. If
1008 * there is an entry at that position that starts with
1009 * "$refname/" and is not in skip, then we have a
1010 * conflict.
1011 */
1012 for (pos = string_list_find_insert_index(extras, dirname.buf, 0);
1013 pos < extras->nr; pos++) {
1014 const char *extra_refname = extras->items[pos].string;
1015
1016 if (!starts_with(extra_refname, dirname.buf))
1017 break;
1018
1019 if (!skip || !string_list_has_string(skip, extra_refname)) {
1020 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1021 refname, extra_refname);
1022 goto cleanup;
1023 }
1024 }
1025 }
1026
1027 /* No conflicts were found */
1028 ret = 0;
1029
1030 cleanup:
1031 strbuf_release(&dirname);
1032 return ret;
1033 }
1034
1035 struct packed_ref_cache {
1036 struct ref_entry *root;
1037
1038 /*
1039 * Count of references to the data structure in this instance,
1040 * including the pointer from ref_cache::packed if any. The
1041 * data will not be freed as long as the reference count is
1042 * nonzero.
1043 */
1044 unsigned int referrers;
1045
1046 /*
1047 * Iff the packed-refs file associated with this instance is
1048 * currently locked for writing, this points at the associated
1049 * lock (which is owned by somebody else). The referrer count
1050 * is also incremented when the file is locked and decremented
1051 * when it is unlocked.
1052 */
1053 struct lock_file *lock;
1054
1055 /* The metadata from when this packed-refs cache was read */
1056 struct stat_validity validity;
1057 };
1058
1059 /*
1060 * Future: need to be in "struct repository"
1061 * when doing a full libification.
1062 */
1063 static struct ref_cache {
1064 struct ref_cache *next;
1065 struct ref_entry *loose;
1066 struct packed_ref_cache *packed;
1067 /*
1068 * The submodule name, or "" for the main repo. We allocate
1069 * length 1 rather than FLEX_ARRAY so that the main ref_cache
1070 * is initialized correctly.
1071 */
1072 char name[1];
1073 } ref_cache, *submodule_ref_caches;
1074
1075 /* Lock used for the main packed-refs file: */
1076 static struct lock_file packlock;
1077
1078 /*
1079 * Increment the reference count of *packed_refs.
1080 */
1081 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
1082 {
1083 packed_refs->referrers++;
1084 }
1085
1086 /*
1087 * Decrease the reference count of *packed_refs. If it goes to zero,
1088 * free *packed_refs and return true; otherwise return false.
1089 */
1090 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
1091 {
1092 if (!--packed_refs->referrers) {
1093 free_ref_entry(packed_refs->root);
1094 stat_validity_clear(&packed_refs->validity);
1095 free(packed_refs);
1096 return 1;
1097 } else {
1098 return 0;
1099 }
1100 }
1101
1102 static void clear_packed_ref_cache(struct ref_cache *refs)
1103 {
1104 if (refs->packed) {
1105 struct packed_ref_cache *packed_refs = refs->packed;
1106
1107 if (packed_refs->lock)
1108 die("internal error: packed-ref cache cleared while locked");
1109 refs->packed = NULL;
1110 release_packed_ref_cache(packed_refs);
1111 }
1112 }
1113
1114 static void clear_loose_ref_cache(struct ref_cache *refs)
1115 {
1116 if (refs->loose) {
1117 free_ref_entry(refs->loose);
1118 refs->loose = NULL;
1119 }
1120 }
1121
1122 static struct ref_cache *create_ref_cache(const char *submodule)
1123 {
1124 int len;
1125 struct ref_cache *refs;
1126 if (!submodule)
1127 submodule = "";
1128 len = strlen(submodule) + 1;
1129 refs = xcalloc(1, sizeof(struct ref_cache) + len);
1130 memcpy(refs->name, submodule, len);
1131 return refs;
1132 }
1133
1134 /*
1135 * Return a pointer to a ref_cache for the specified submodule. For
1136 * the main repository, use submodule==NULL. The returned structure
1137 * will be allocated and initialized but not necessarily populated; it
1138 * should not be freed.
1139 */
1140 static struct ref_cache *get_ref_cache(const char *submodule)
1141 {
1142 struct ref_cache *refs;
1143
1144 if (!submodule || !*submodule)
1145 return &ref_cache;
1146
1147 for (refs = submodule_ref_caches; refs; refs = refs->next)
1148 if (!strcmp(submodule, refs->name))
1149 return refs;
1150
1151 refs = create_ref_cache(submodule);
1152 refs->next = submodule_ref_caches;
1153 submodule_ref_caches = refs;
1154 return refs;
1155 }
1156
1157 /* The length of a peeled reference line in packed-refs, including EOL: */
1158 #define PEELED_LINE_LENGTH 42
1159
1160 /*
1161 * The packed-refs header line that we write out. Perhaps other
1162 * traits will be added later. The trailing space is required.
1163 */
1164 static const char PACKED_REFS_HEADER[] =
1165 "# pack-refs with: peeled fully-peeled \n";
1166
1167 /*
1168 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1169 * Return a pointer to the refname within the line (null-terminated),
1170 * or NULL if there was a problem.
1171 */
1172 static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1173 {
1174 const char *ref;
1175
1176 /*
1177 * 42: the answer to everything.
1178 *
1179 * In this case, it happens to be the answer to
1180 * 40 (length of sha1 hex representation)
1181 * +1 (space in between hex and name)
1182 * +1 (newline at the end of the line)
1183 */
1184 if (line->len <= 42)
1185 return NULL;
1186
1187 if (get_sha1_hex(line->buf, sha1) < 0)
1188 return NULL;
1189 if (!isspace(line->buf[40]))
1190 return NULL;
1191
1192 ref = line->buf + 41;
1193 if (isspace(*ref))
1194 return NULL;
1195
1196 if (line->buf[line->len - 1] != '\n')
1197 return NULL;
1198 line->buf[--line->len] = 0;
1199
1200 return ref;
1201 }
1202
1203 /*
1204 * Read f, which is a packed-refs file, into dir.
1205 *
1206 * A comment line of the form "# pack-refs with: " may contain zero or
1207 * more traits. We interpret the traits as follows:
1208 *
1209 * No traits:
1210 *
1211 * Probably no references are peeled. But if the file contains a
1212 * peeled value for a reference, we will use it.
1213 *
1214 * peeled:
1215 *
1216 * References under "refs/tags/", if they *can* be peeled, *are*
1217 * peeled in this file. References outside of "refs/tags/" are
1218 * probably not peeled even if they could have been, but if we find
1219 * a peeled value for such a reference we will use it.
1220 *
1221 * fully-peeled:
1222 *
1223 * All references in the file that can be peeled are peeled.
1224 * Inversely (and this is more important), any references in the
1225 * file for which no peeled value is recorded is not peelable. This
1226 * trait should typically be written alongside "peeled" for
1227 * compatibility with older clients, but we do not require it
1228 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1229 */
1230 static void read_packed_refs(FILE *f, struct ref_dir *dir)
1231 {
1232 struct ref_entry *last = NULL;
1233 struct strbuf line = STRBUF_INIT;
1234 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1235
1236 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1237 unsigned char sha1[20];
1238 const char *refname;
1239 const char *traits;
1240
1241 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1242 if (strstr(traits, " fully-peeled "))
1243 peeled = PEELED_FULLY;
1244 else if (strstr(traits, " peeled "))
1245 peeled = PEELED_TAGS;
1246 /* perhaps other traits later as well */
1247 continue;
1248 }
1249
1250 refname = parse_ref_line(&line, sha1);
1251 if (refname) {
1252 int flag = REF_ISPACKED;
1253
1254 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1255 if (!refname_is_safe(refname))
1256 die("packed refname is dangerous: %s", refname);
1257 hashclr(sha1);
1258 flag |= REF_BAD_NAME | REF_ISBROKEN;
1259 }
1260 last = create_ref_entry(refname, sha1, flag, 0);
1261 if (peeled == PEELED_FULLY ||
1262 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1263 last->flag |= REF_KNOWS_PEELED;
1264 add_ref(dir, last);
1265 continue;
1266 }
1267 if (last &&
1268 line.buf[0] == '^' &&
1269 line.len == PEELED_LINE_LENGTH &&
1270 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1271 !get_sha1_hex(line.buf + 1, sha1)) {
1272 hashcpy(last->u.value.peeled.hash, sha1);
1273 /*
1274 * Regardless of what the file header said,
1275 * we definitely know the value of *this*
1276 * reference:
1277 */
1278 last->flag |= REF_KNOWS_PEELED;
1279 }
1280 }
1281
1282 strbuf_release(&line);
1283 }
1284
1285 /*
1286 * Get the packed_ref_cache for the specified ref_cache, creating it
1287 * if necessary.
1288 */
1289 static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1290 {
1291 char *packed_refs_file;
1292
1293 if (*refs->name)
1294 packed_refs_file = git_pathdup_submodule(refs->name, "packed-refs");
1295 else
1296 packed_refs_file = git_pathdup("packed-refs");
1297
1298 if (refs->packed &&
1299 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1300 clear_packed_ref_cache(refs);
1301
1302 if (!refs->packed) {
1303 FILE *f;
1304
1305 refs->packed = xcalloc(1, sizeof(*refs->packed));
1306 acquire_packed_ref_cache(refs->packed);
1307 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1308 f = fopen(packed_refs_file, "r");
1309 if (f) {
1310 stat_validity_update(&refs->packed->validity, fileno(f));
1311 read_packed_refs(f, get_ref_dir(refs->packed->root));
1312 fclose(f);
1313 }
1314 }
1315 free(packed_refs_file);
1316 return refs->packed;
1317 }
1318
1319 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1320 {
1321 return get_ref_dir(packed_ref_cache->root);
1322 }
1323
1324 static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1325 {
1326 return get_packed_ref_dir(get_packed_ref_cache(refs));
1327 }
1328
1329 /*
1330 * Add a reference to the in-memory packed reference cache. This may
1331 * only be called while the packed-refs file is locked (see
1332 * lock_packed_refs()). To actually write the packed-refs file, call
1333 * commit_packed_refs().
1334 */
1335 static void add_packed_ref(const char *refname, const unsigned char *sha1)
1336 {
1337 struct packed_ref_cache *packed_ref_cache =
1338 get_packed_ref_cache(&ref_cache);
1339
1340 if (!packed_ref_cache->lock)
1341 die("internal error: packed refs not locked");
1342 add_ref(get_packed_ref_dir(packed_ref_cache),
1343 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1344 }
1345
1346 /*
1347 * Read the loose references from the namespace dirname into dir
1348 * (without recursing). dirname must end with '/'. dir must be the
1349 * directory entry corresponding to dirname.
1350 */
1351 static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1352 {
1353 struct ref_cache *refs = dir->ref_cache;
1354 DIR *d;
1355 struct dirent *de;
1356 int dirnamelen = strlen(dirname);
1357 struct strbuf refname;
1358 struct strbuf path = STRBUF_INIT;
1359 size_t path_baselen;
1360
1361 if (*refs->name)
1362 strbuf_git_path_submodule(&path, refs->name, "%s", dirname);
1363 else
1364 strbuf_git_path(&path, "%s", dirname);
1365 path_baselen = path.len;
1366
1367 d = opendir(path.buf);
1368 if (!d) {
1369 strbuf_release(&path);
1370 return;
1371 }
1372
1373 strbuf_init(&refname, dirnamelen + 257);
1374 strbuf_add(&refname, dirname, dirnamelen);
1375
1376 while ((de = readdir(d)) != NULL) {
1377 unsigned char sha1[20];
1378 struct stat st;
1379 int flag;
1380
1381 if (de->d_name[0] == '.')
1382 continue;
1383 if (ends_with(de->d_name, ".lock"))
1384 continue;
1385 strbuf_addstr(&refname, de->d_name);
1386 strbuf_addstr(&path, de->d_name);
1387 if (stat(path.buf, &st) < 0) {
1388 ; /* silently ignore */
1389 } else if (S_ISDIR(st.st_mode)) {
1390 strbuf_addch(&refname, '/');
1391 add_entry_to_dir(dir,
1392 create_dir_entry(refs, refname.buf,
1393 refname.len, 1));
1394 } else {
1395 int read_ok;
1396
1397 if (*refs->name) {
1398 hashclr(sha1);
1399 flag = 0;
1400 read_ok = !resolve_gitlink_ref(refs->name,
1401 refname.buf, sha1);
1402 } else {
1403 read_ok = !read_ref_full(refname.buf,
1404 RESOLVE_REF_READING,
1405 sha1, &flag);
1406 }
1407
1408 if (!read_ok) {
1409 hashclr(sha1);
1410 flag |= REF_ISBROKEN;
1411 } else if (is_null_sha1(sha1)) {
1412 /*
1413 * It is so astronomically unlikely
1414 * that NULL_SHA1 is the SHA-1 of an
1415 * actual object that we consider its
1416 * appearance in a loose reference
1417 * file to be repo corruption
1418 * (probably due to a software bug).
1419 */
1420 flag |= REF_ISBROKEN;
1421 }
1422
1423 if (check_refname_format(refname.buf,
1424 REFNAME_ALLOW_ONELEVEL)) {
1425 if (!refname_is_safe(refname.buf))
1426 die("loose refname is dangerous: %s", refname.buf);
1427 hashclr(sha1);
1428 flag |= REF_BAD_NAME | REF_ISBROKEN;
1429 }
1430 add_entry_to_dir(dir,
1431 create_ref_entry(refname.buf, sha1, flag, 0));
1432 }
1433 strbuf_setlen(&refname, dirnamelen);
1434 strbuf_setlen(&path, path_baselen);
1435 }
1436 strbuf_release(&refname);
1437 strbuf_release(&path);
1438 closedir(d);
1439 }
1440
1441 static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1442 {
1443 if (!refs->loose) {
1444 /*
1445 * Mark the top-level directory complete because we
1446 * are about to read the only subdirectory that can
1447 * hold references:
1448 */
1449 refs->loose = create_dir_entry(refs, "", 0, 0);
1450 /*
1451 * Create an incomplete entry for "refs/":
1452 */
1453 add_entry_to_dir(get_ref_dir(refs->loose),
1454 create_dir_entry(refs, "refs/", 5, 1));
1455 }
1456 return get_ref_dir(refs->loose);
1457 }
1458
1459 /* We allow "recursive" symbolic refs. Only within reason, though */
1460 #define MAXDEPTH 5
1461 #define MAXREFLEN (1024)
1462
1463 /*
1464 * Called by resolve_gitlink_ref_recursive() after it failed to read
1465 * from the loose refs in ref_cache refs. Find <refname> in the
1466 * packed-refs file for the submodule.
1467 */
1468 static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1469 const char *refname, unsigned char *sha1)
1470 {
1471 struct ref_entry *ref;
1472 struct ref_dir *dir = get_packed_refs(refs);
1473
1474 ref = find_ref(dir, refname);
1475 if (ref == NULL)
1476 return -1;
1477
1478 hashcpy(sha1, ref->u.value.oid.hash);
1479 return 0;
1480 }
1481
1482 static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1483 const char *refname, unsigned char *sha1,
1484 int recursion)
1485 {
1486 int fd, len;
1487 char buffer[128], *p;
1488 char *path;
1489
1490 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1491 return -1;
1492 path = *refs->name
1493 ? git_pathdup_submodule(refs->name, "%s", refname)
1494 : git_pathdup("%s", refname);
1495 fd = open(path, O_RDONLY);
1496 free(path);
1497 if (fd < 0)
1498 return resolve_gitlink_packed_ref(refs, refname, sha1);
1499
1500 len = read(fd, buffer, sizeof(buffer)-1);
1501 close(fd);
1502 if (len < 0)
1503 return -1;
1504 while (len && isspace(buffer[len-1]))
1505 len--;
1506 buffer[len] = 0;
1507
1508 /* Was it a detached head or an old-fashioned symlink? */
1509 if (!get_sha1_hex(buffer, sha1))
1510 return 0;
1511
1512 /* Symref? */
1513 if (strncmp(buffer, "ref:", 4))
1514 return -1;
1515 p = buffer + 4;
1516 while (isspace(*p))
1517 p++;
1518
1519 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1520 }
1521
1522 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1523 {
1524 int len = strlen(path), retval;
1525 char *submodule;
1526 struct ref_cache *refs;
1527
1528 while (len && path[len-1] == '/')
1529 len--;
1530 if (!len)
1531 return -1;
1532 submodule = xstrndup(path, len);
1533 refs = get_ref_cache(submodule);
1534 free(submodule);
1535
1536 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1537 return retval;
1538 }
1539
1540 /*
1541 * Return the ref_entry for the given refname from the packed
1542 * references. If it does not exist, return NULL.
1543 */
1544 static struct ref_entry *get_packed_ref(const char *refname)
1545 {
1546 return find_ref(get_packed_refs(&ref_cache), refname);
1547 }
1548
1549 /*
1550 * A loose ref file doesn't exist; check for a packed ref. The
1551 * options are forwarded from resolve_safe_unsafe().
1552 */
1553 static int resolve_missing_loose_ref(const char *refname,
1554 int resolve_flags,
1555 unsigned char *sha1,
1556 int *flags)
1557 {
1558 struct ref_entry *entry;
1559
1560 /*
1561 * The loose reference file does not exist; check for a packed
1562 * reference.
1563 */
1564 entry = get_packed_ref(refname);
1565 if (entry) {
1566 hashcpy(sha1, entry->u.value.oid.hash);
1567 if (flags)
1568 *flags |= REF_ISPACKED;
1569 return 0;
1570 }
1571 /* The reference is not a packed reference, either. */
1572 if (resolve_flags & RESOLVE_REF_READING) {
1573 errno = ENOENT;
1574 return -1;
1575 } else {
1576 hashclr(sha1);
1577 return 0;
1578 }
1579 }
1580
1581 /* This function needs to return a meaningful errno on failure */
1582 static const char *resolve_ref_unsafe_1(const char *refname,
1583 int resolve_flags,
1584 unsigned char *sha1,
1585 int *flags,
1586 struct strbuf *sb_path)
1587 {
1588 int depth = MAXDEPTH;
1589 ssize_t len;
1590 char buffer[256];
1591 static char refname_buffer[256];
1592 int bad_name = 0;
1593
1594 if (flags)
1595 *flags = 0;
1596
1597 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1598 if (flags)
1599 *flags |= REF_BAD_NAME;
1600
1601 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1602 !refname_is_safe(refname)) {
1603 errno = EINVAL;
1604 return NULL;
1605 }
1606 /*
1607 * dwim_ref() uses REF_ISBROKEN to distinguish between
1608 * missing refs and refs that were present but invalid,
1609 * to complain about the latter to stderr.
1610 *
1611 * We don't know whether the ref exists, so don't set
1612 * REF_ISBROKEN yet.
1613 */
1614 bad_name = 1;
1615 }
1616 for (;;) {
1617 const char *path;
1618 struct stat st;
1619 char *buf;
1620 int fd;
1621
1622 if (--depth < 0) {
1623 errno = ELOOP;
1624 return NULL;
1625 }
1626
1627 strbuf_reset(sb_path);
1628 strbuf_git_path(sb_path, "%s", refname);
1629 path = sb_path->buf;
1630
1631 /*
1632 * We might have to loop back here to avoid a race
1633 * condition: first we lstat() the file, then we try
1634 * to read it as a link or as a file. But if somebody
1635 * changes the type of the file (file <-> directory
1636 * <-> symlink) between the lstat() and reading, then
1637 * we don't want to report that as an error but rather
1638 * try again starting with the lstat().
1639 */
1640 stat_ref:
1641 if (lstat(path, &st) < 0) {
1642 if (errno != ENOENT)
1643 return NULL;
1644 if (resolve_missing_loose_ref(refname, resolve_flags,
1645 sha1, flags))
1646 return NULL;
1647 if (bad_name) {
1648 hashclr(sha1);
1649 if (flags)
1650 *flags |= REF_ISBROKEN;
1651 }
1652 return refname;
1653 }
1654
1655 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1656 if (S_ISLNK(st.st_mode)) {
1657 len = readlink(path, buffer, sizeof(buffer)-1);
1658 if (len < 0) {
1659 if (errno == ENOENT || errno == EINVAL)
1660 /* inconsistent with lstat; retry */
1661 goto stat_ref;
1662 else
1663 return NULL;
1664 }
1665 buffer[len] = 0;
1666 if (starts_with(buffer, "refs/") &&
1667 !check_refname_format(buffer, 0)) {
1668 strcpy(refname_buffer, buffer);
1669 refname = refname_buffer;
1670 if (flags)
1671 *flags |= REF_ISSYMREF;
1672 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1673 hashclr(sha1);
1674 return refname;
1675 }
1676 continue;
1677 }
1678 }
1679
1680 /* Is it a directory? */
1681 if (S_ISDIR(st.st_mode)) {
1682 errno = EISDIR;
1683 return NULL;
1684 }
1685
1686 /*
1687 * Anything else, just open it and try to use it as
1688 * a ref
1689 */
1690 fd = open(path, O_RDONLY);
1691 if (fd < 0) {
1692 if (errno == ENOENT)
1693 /* inconsistent with lstat; retry */
1694 goto stat_ref;
1695 else
1696 return NULL;
1697 }
1698 len = read_in_full(fd, buffer, sizeof(buffer)-1);
1699 if (len < 0) {
1700 int save_errno = errno;
1701 close(fd);
1702 errno = save_errno;
1703 return NULL;
1704 }
1705 close(fd);
1706 while (len && isspace(buffer[len-1]))
1707 len--;
1708 buffer[len] = '\0';
1709
1710 /*
1711 * Is it a symbolic ref?
1712 */
1713 if (!starts_with(buffer, "ref:")) {
1714 /*
1715 * Please note that FETCH_HEAD has a second
1716 * line containing other data.
1717 */
1718 if (get_sha1_hex(buffer, sha1) ||
1719 (buffer[40] != '\0' && !isspace(buffer[40]))) {
1720 if (flags)
1721 *flags |= REF_ISBROKEN;
1722 errno = EINVAL;
1723 return NULL;
1724 }
1725 if (bad_name) {
1726 hashclr(sha1);
1727 if (flags)
1728 *flags |= REF_ISBROKEN;
1729 }
1730 return refname;
1731 }
1732 if (flags)
1733 *flags |= REF_ISSYMREF;
1734 buf = buffer + 4;
1735 while (isspace(*buf))
1736 buf++;
1737 refname = strcpy(refname_buffer, buf);
1738 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1739 hashclr(sha1);
1740 return refname;
1741 }
1742 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1743 if (flags)
1744 *flags |= REF_ISBROKEN;
1745
1746 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1747 !refname_is_safe(buf)) {
1748 errno = EINVAL;
1749 return NULL;
1750 }
1751 bad_name = 1;
1752 }
1753 }
1754 }
1755
1756 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1757 unsigned char *sha1, int *flags)
1758 {
1759 struct strbuf sb_path = STRBUF_INIT;
1760 const char *ret = resolve_ref_unsafe_1(refname, resolve_flags,
1761 sha1, flags, &sb_path);
1762 strbuf_release(&sb_path);
1763 return ret;
1764 }
1765
1766 char *resolve_refdup(const char *refname, int resolve_flags,
1767 unsigned char *sha1, int *flags)
1768 {
1769 return xstrdup_or_null(resolve_ref_unsafe(refname, resolve_flags,
1770 sha1, flags));
1771 }
1772
1773 /* The argument to filter_refs */
1774 struct ref_filter {
1775 const char *pattern;
1776 each_ref_fn *fn;
1777 void *cb_data;
1778 };
1779
1780 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1781 {
1782 if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
1783 return 0;
1784 return -1;
1785 }
1786
1787 int read_ref(const char *refname, unsigned char *sha1)
1788 {
1789 return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
1790 }
1791
1792 int ref_exists(const char *refname)
1793 {
1794 unsigned char sha1[20];
1795 return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
1796 }
1797
1798 static int filter_refs(const char *refname, const struct object_id *oid,
1799 int flags, void *data)
1800 {
1801 struct ref_filter *filter = (struct ref_filter *)data;
1802
1803 if (wildmatch(filter->pattern, refname, 0, NULL))
1804 return 0;
1805 return filter->fn(refname, oid, flags, filter->cb_data);
1806 }
1807
1808 enum peel_status {
1809 /* object was peeled successfully: */
1810 PEEL_PEELED = 0,
1811
1812 /*
1813 * object cannot be peeled because the named object (or an
1814 * object referred to by a tag in the peel chain), does not
1815 * exist.
1816 */
1817 PEEL_INVALID = -1,
1818
1819 /* object cannot be peeled because it is not a tag: */
1820 PEEL_NON_TAG = -2,
1821
1822 /* ref_entry contains no peeled value because it is a symref: */
1823 PEEL_IS_SYMREF = -3,
1824
1825 /*
1826 * ref_entry cannot be peeled because it is broken (i.e., the
1827 * symbolic reference cannot even be resolved to an object
1828 * name):
1829 */
1830 PEEL_BROKEN = -4
1831 };
1832
1833 /*
1834 * Peel the named object; i.e., if the object is a tag, resolve the
1835 * tag recursively until a non-tag is found. If successful, store the
1836 * result to sha1 and return PEEL_PEELED. If the object is not a tag
1837 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
1838 * and leave sha1 unchanged.
1839 */
1840 static enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
1841 {
1842 struct object *o = lookup_unknown_object(name);
1843
1844 if (o->type == OBJ_NONE) {
1845 int type = sha1_object_info(name, NULL);
1846 if (type < 0 || !object_as_type(o, type, 0))
1847 return PEEL_INVALID;
1848 }
1849
1850 if (o->type != OBJ_TAG)
1851 return PEEL_NON_TAG;
1852
1853 o = deref_tag_noverify(o);
1854 if (!o)
1855 return PEEL_INVALID;
1856
1857 hashcpy(sha1, o->sha1);
1858 return PEEL_PEELED;
1859 }
1860
1861 /*
1862 * Peel the entry (if possible) and return its new peel_status. If
1863 * repeel is true, re-peel the entry even if there is an old peeled
1864 * value that is already stored in it.
1865 *
1866 * It is OK to call this function with a packed reference entry that
1867 * might be stale and might even refer to an object that has since
1868 * been garbage-collected. In such a case, if the entry has
1869 * REF_KNOWS_PEELED then leave the status unchanged and return
1870 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1871 */
1872 static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1873 {
1874 enum peel_status status;
1875
1876 if (entry->flag & REF_KNOWS_PEELED) {
1877 if (repeel) {
1878 entry->flag &= ~REF_KNOWS_PEELED;
1879 oidclr(&entry->u.value.peeled);
1880 } else {
1881 return is_null_oid(&entry->u.value.peeled) ?
1882 PEEL_NON_TAG : PEEL_PEELED;
1883 }
1884 }
1885 if (entry->flag & REF_ISBROKEN)
1886 return PEEL_BROKEN;
1887 if (entry->flag & REF_ISSYMREF)
1888 return PEEL_IS_SYMREF;
1889
1890 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1891 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1892 entry->flag |= REF_KNOWS_PEELED;
1893 return status;
1894 }
1895
1896 int peel_ref(const char *refname, unsigned char *sha1)
1897 {
1898 int flag;
1899 unsigned char base[20];
1900
1901 if (current_ref && (current_ref->name == refname
1902 || !strcmp(current_ref->name, refname))) {
1903 if (peel_entry(current_ref, 0))
1904 return -1;
1905 hashcpy(sha1, current_ref->u.value.peeled.hash);
1906 return 0;
1907 }
1908
1909 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1910 return -1;
1911
1912 /*
1913 * If the reference is packed, read its ref_entry from the
1914 * cache in the hope that we already know its peeled value.
1915 * We only try this optimization on packed references because
1916 * (a) forcing the filling of the loose reference cache could
1917 * be expensive and (b) loose references anyway usually do not
1918 * have REF_KNOWS_PEELED.
1919 */
1920 if (flag & REF_ISPACKED) {
1921 struct ref_entry *r = get_packed_ref(refname);
1922 if (r) {
1923 if (peel_entry(r, 0))
1924 return -1;
1925 hashcpy(sha1, r->u.value.peeled.hash);
1926 return 0;
1927 }
1928 }
1929
1930 return peel_object(base, sha1);
1931 }
1932
1933 struct warn_if_dangling_data {
1934 FILE *fp;
1935 const char *refname;
1936 const struct string_list *refnames;
1937 const char *msg_fmt;
1938 };
1939
1940 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
1941 int flags, void *cb_data)
1942 {
1943 struct warn_if_dangling_data *d = cb_data;
1944 const char *resolves_to;
1945 struct object_id junk;
1946
1947 if (!(flags & REF_ISSYMREF))
1948 return 0;
1949
1950 resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
1951 if (!resolves_to
1952 || (d->refname
1953 ? strcmp(resolves_to, d->refname)
1954 : !string_list_has_string(d->refnames, resolves_to))) {
1955 return 0;
1956 }
1957
1958 fprintf(d->fp, d->msg_fmt, refname);
1959 fputc('\n', d->fp);
1960 return 0;
1961 }
1962
1963 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1964 {
1965 struct warn_if_dangling_data data;
1966
1967 data.fp = fp;
1968 data.refname = refname;
1969 data.refnames = NULL;
1970 data.msg_fmt = msg_fmt;
1971 for_each_rawref(warn_if_dangling_symref, &data);
1972 }
1973
1974 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
1975 {
1976 struct warn_if_dangling_data data;
1977
1978 data.fp = fp;
1979 data.refname = NULL;
1980 data.refnames = refnames;
1981 data.msg_fmt = msg_fmt;
1982 for_each_rawref(warn_if_dangling_symref, &data);
1983 }
1984
1985 /*
1986 * Call fn for each reference in the specified ref_cache, omitting
1987 * references not in the containing_dir of base. fn is called for all
1988 * references, including broken ones. If fn ever returns a non-zero
1989 * value, stop the iteration and return that value; otherwise, return
1990 * 0.
1991 */
1992 static int do_for_each_entry(struct ref_cache *refs, const char *base,
1993 each_ref_entry_fn fn, void *cb_data)
1994 {
1995 struct packed_ref_cache *packed_ref_cache;
1996 struct ref_dir *loose_dir;
1997 struct ref_dir *packed_dir;
1998 int retval = 0;
1999
2000 /*
2001 * We must make sure that all loose refs are read before accessing the
2002 * packed-refs file; this avoids a race condition in which loose refs
2003 * are migrated to the packed-refs file by a simultaneous process, but
2004 * our in-memory view is from before the migration. get_packed_ref_cache()
2005 * takes care of making sure our view is up to date with what is on
2006 * disk.
2007 */
2008 loose_dir = get_loose_refs(refs);
2009 if (base && *base) {
2010 loose_dir = find_containing_dir(loose_dir, base, 0);
2011 }
2012 if (loose_dir)
2013 prime_ref_dir(loose_dir);
2014
2015 packed_ref_cache = get_packed_ref_cache(refs);
2016 acquire_packed_ref_cache(packed_ref_cache);
2017 packed_dir = get_packed_ref_dir(packed_ref_cache);
2018 if (base && *base) {
2019 packed_dir = find_containing_dir(packed_dir, base, 0);
2020 }
2021
2022 if (packed_dir && loose_dir) {
2023 sort_ref_dir(packed_dir);
2024 sort_ref_dir(loose_dir);
2025 retval = do_for_each_entry_in_dirs(
2026 packed_dir, loose_dir, fn, cb_data);
2027 } else if (packed_dir) {
2028 sort_ref_dir(packed_dir);
2029 retval = do_for_each_entry_in_dir(
2030 packed_dir, 0, fn, cb_data);
2031 } else if (loose_dir) {
2032 sort_ref_dir(loose_dir);
2033 retval = do_for_each_entry_in_dir(
2034 loose_dir, 0, fn, cb_data);
2035 }
2036
2037 release_packed_ref_cache(packed_ref_cache);
2038 return retval;
2039 }
2040
2041 /*
2042 * Call fn for each reference in the specified ref_cache for which the
2043 * refname begins with base. If trim is non-zero, then trim that many
2044 * characters off the beginning of each refname before passing the
2045 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
2046 * broken references in the iteration. If fn ever returns a non-zero
2047 * value, stop the iteration and return that value; otherwise, return
2048 * 0.
2049 */
2050 static int do_for_each_ref(struct ref_cache *refs, const char *base,
2051 each_ref_fn fn, int trim, int flags, void *cb_data)
2052 {
2053 struct ref_entry_cb data;
2054 data.base = base;
2055 data.trim = trim;
2056 data.flags = flags;
2057 data.fn = fn;
2058 data.cb_data = cb_data;
2059
2060 if (ref_paranoia < 0)
2061 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
2062 if (ref_paranoia)
2063 data.flags |= DO_FOR_EACH_INCLUDE_BROKEN;
2064
2065 return do_for_each_entry(refs, base, do_one_ref, &data);
2066 }
2067
2068 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
2069 {
2070 struct object_id oid;
2071 int flag;
2072
2073 if (submodule) {
2074 if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
2075 return fn("HEAD", &oid, 0, cb_data);
2076
2077 return 0;
2078 }
2079
2080 if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
2081 return fn("HEAD", &oid, flag, cb_data);
2082
2083 return 0;
2084 }
2085
2086 int head_ref(each_ref_fn fn, void *cb_data)
2087 {
2088 return do_head_ref(NULL, fn, cb_data);
2089 }
2090
2091 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2092 {
2093 return do_head_ref(submodule, fn, cb_data);
2094 }
2095
2096 int for_each_ref(each_ref_fn fn, void *cb_data)
2097 {
2098 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
2099 }
2100
2101 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2102 {
2103 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
2104 }
2105
2106 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
2107 {
2108 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
2109 }
2110
2111 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
2112 each_ref_fn fn, void *cb_data)
2113 {
2114 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
2115 }
2116
2117 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
2118 {
2119 return for_each_ref_in("refs/tags/", fn, cb_data);
2120 }
2121
2122 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2123 {
2124 return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
2125 }
2126
2127 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
2128 {
2129 return for_each_ref_in("refs/heads/", fn, cb_data);
2130 }
2131
2132 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2133 {
2134 return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
2135 }
2136
2137 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
2138 {
2139 return for_each_ref_in("refs/remotes/", fn, cb_data);
2140 }
2141
2142 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2143 {
2144 return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
2145 }
2146
2147 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
2148 {
2149 return do_for_each_ref(&ref_cache, git_replace_ref_base, fn,
2150 strlen(git_replace_ref_base), 0, cb_data);
2151 }
2152
2153 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
2154 {
2155 struct strbuf buf = STRBUF_INIT;
2156 int ret = 0;
2157 struct object_id oid;
2158 int flag;
2159
2160 strbuf_addf(&buf, "%sHEAD", get_git_namespace());
2161 if (!read_ref_full(buf.buf, RESOLVE_REF_READING, oid.hash, &flag))
2162 ret = fn(buf.buf, &oid, flag, cb_data);
2163 strbuf_release(&buf);
2164
2165 return ret;
2166 }
2167
2168 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
2169 {
2170 struct strbuf buf = STRBUF_INIT;
2171 int ret;
2172 strbuf_addf(&buf, "%srefs/", get_git_namespace());
2173 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
2174 strbuf_release(&buf);
2175 return ret;
2176 }
2177
2178 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
2179 const char *prefix, void *cb_data)
2180 {
2181 struct strbuf real_pattern = STRBUF_INIT;
2182 struct ref_filter filter;
2183 int ret;
2184
2185 if (!prefix && !starts_with(pattern, "refs/"))
2186 strbuf_addstr(&real_pattern, "refs/");
2187 else if (prefix)
2188 strbuf_addstr(&real_pattern, prefix);
2189 strbuf_addstr(&real_pattern, pattern);
2190
2191 if (!has_glob_specials(pattern)) {
2192 /* Append implied '/' '*' if not present. */
2193 if (real_pattern.buf[real_pattern.len - 1] != '/')
2194 strbuf_addch(&real_pattern, '/');
2195 /* No need to check for '*', there is none. */
2196 strbuf_addch(&real_pattern, '*');
2197 }
2198
2199 filter.pattern = real_pattern.buf;
2200 filter.fn = fn;
2201 filter.cb_data = cb_data;
2202 ret = for_each_ref(filter_refs, &filter);
2203
2204 strbuf_release(&real_pattern);
2205 return ret;
2206 }
2207
2208 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
2209 {
2210 return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
2211 }
2212
2213 int for_each_rawref(each_ref_fn fn, void *cb_data)
2214 {
2215 return do_for_each_ref(&ref_cache, "", fn, 0,
2216 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
2217 }
2218
2219 const char *prettify_refname(const char *name)
2220 {
2221 return name + (
2222 starts_with(name, "refs/heads/") ? 11 :
2223 starts_with(name, "refs/tags/") ? 10 :
2224 starts_with(name, "refs/remotes/") ? 13 :
2225 0);
2226 }
2227
2228 static const char *ref_rev_parse_rules[] = {
2229 "%.*s",
2230 "refs/%.*s",
2231 "refs/tags/%.*s",
2232 "refs/heads/%.*s",
2233 "refs/remotes/%.*s",
2234 "refs/remotes/%.*s/HEAD",
2235 NULL
2236 };
2237
2238 int refname_match(const char *abbrev_name, const char *full_name)
2239 {
2240 const char **p;
2241 const int abbrev_name_len = strlen(abbrev_name);
2242
2243 for (p = ref_rev_parse_rules; *p; p++) {
2244 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
2245 return 1;
2246 }
2247 }
2248
2249 return 0;
2250 }
2251
2252 static void unlock_ref(struct ref_lock *lock)
2253 {
2254 /* Do not free lock->lk -- atexit() still looks at them */
2255 if (lock->lk)
2256 rollback_lock_file(lock->lk);
2257 free(lock->ref_name);
2258 free(lock->orig_ref_name);
2259 free(lock);
2260 }
2261
2262 /*
2263 * Verify that the reference locked by lock has the value old_sha1.
2264 * Fail if the reference doesn't exist and mustexist is set. Return 0
2265 * on success. On error, write an error message to err, set errno, and
2266 * return a negative value.
2267 */
2268 static int verify_lock(struct ref_lock *lock,
2269 const unsigned char *old_sha1, int mustexist,
2270 struct strbuf *err)
2271 {
2272 assert(err);
2273
2274 if (read_ref_full(lock->ref_name,
2275 mustexist ? RESOLVE_REF_READING : 0,
2276 lock->old_oid.hash, NULL)) {
2277 int save_errno = errno;
2278 strbuf_addf(err, "can't verify ref %s", lock->ref_name);
2279 errno = save_errno;
2280 return -1;
2281 }
2282 if (hashcmp(lock->old_oid.hash, old_sha1)) {
2283 strbuf_addf(err, "ref %s is at %s but expected %s",
2284 lock->ref_name,
2285 sha1_to_hex(lock->old_oid.hash),
2286 sha1_to_hex(old_sha1));
2287 errno = EBUSY;
2288 return -1;
2289 }
2290 return 0;
2291 }
2292
2293 static int remove_empty_directories(struct strbuf *path)
2294 {
2295 /*
2296 * we want to create a file but there is a directory there;
2297 * if that is an empty directory (or a directory that contains
2298 * only empty directories), remove them.
2299 */
2300 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
2301 }
2302
2303 /*
2304 * *string and *len will only be substituted, and *string returned (for
2305 * later free()ing) if the string passed in is a magic short-hand form
2306 * to name a branch.
2307 */
2308 static char *substitute_branch_name(const char **string, int *len)
2309 {
2310 struct strbuf buf = STRBUF_INIT;
2311 int ret = interpret_branch_name(*string, *len, &buf);
2312
2313 if (ret == *len) {
2314 size_t size;
2315 *string = strbuf_detach(&buf, &size);
2316 *len = size;
2317 return (char *)*string;
2318 }
2319
2320 return NULL;
2321 }
2322
2323 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
2324 {
2325 char *last_branch = substitute_branch_name(&str, &len);
2326 const char **p, *r;
2327 int refs_found = 0;
2328
2329 *ref = NULL;
2330 for (p = ref_rev_parse_rules; *p; p++) {
2331 char fullref[PATH_MAX];
2332 unsigned char sha1_from_ref[20];
2333 unsigned char *this_result;
2334 int flag;
2335
2336 this_result = refs_found ? sha1_from_ref : sha1;
2337 mksnpath(fullref, sizeof(fullref), *p, len, str);
2338 r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
2339 this_result, &flag);
2340 if (r) {
2341 if (!refs_found++)
2342 *ref = xstrdup(r);
2343 if (!warn_ambiguous_refs)
2344 break;
2345 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
2346 warning("ignoring dangling symref %s.", fullref);
2347 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
2348 warning("ignoring broken ref %s.", fullref);
2349 }
2350 }
2351 free(last_branch);
2352 return refs_found;
2353 }
2354
2355 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
2356 {
2357 char *last_branch = substitute_branch_name(&str, &len);
2358 const char **p;
2359 int logs_found = 0;
2360
2361 *log = NULL;
2362 for (p = ref_rev_parse_rules; *p; p++) {
2363 unsigned char hash[20];
2364 char path[PATH_MAX];
2365 const char *ref, *it;
2366
2367 mksnpath(path, sizeof(path), *p, len, str);
2368 ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
2369 hash, NULL);
2370 if (!ref)
2371 continue;
2372 if (reflog_exists(path))
2373 it = path;
2374 else if (strcmp(ref, path) && reflog_exists(ref))
2375 it = ref;
2376 else
2377 continue;
2378 if (!logs_found++) {
2379 *log = xstrdup(it);
2380 hashcpy(sha1, hash);
2381 }
2382 if (!warn_ambiguous_refs)
2383 break;
2384 }
2385 free(last_branch);
2386 return logs_found;
2387 }
2388
2389 /*
2390 * Locks a ref returning the lock on success and NULL on failure.
2391 * On failure errno is set to something meaningful.
2392 */
2393 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2394 const unsigned char *old_sha1,
2395 const struct string_list *extras,
2396 const struct string_list *skip,
2397 unsigned int flags, int *type_p,
2398 struct strbuf *err)
2399 {
2400 struct strbuf ref_file = STRBUF_INIT;
2401 struct strbuf orig_ref_file = STRBUF_INIT;
2402 const char *orig_refname = refname;
2403 struct ref_lock *lock;
2404 int last_errno = 0;
2405 int type, lflags;
2406 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
2407 int resolve_flags = 0;
2408 int attempts_remaining = 3;
2409
2410 assert(err);
2411
2412 lock = xcalloc(1, sizeof(struct ref_lock));
2413
2414 if (mustexist)
2415 resolve_flags |= RESOLVE_REF_READING;
2416 if (flags & REF_DELETING) {
2417 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
2418 if (flags & REF_NODEREF)
2419 resolve_flags |= RESOLVE_REF_NO_RECURSE;
2420 }
2421
2422 refname = resolve_ref_unsafe(refname, resolve_flags,
2423 lock->old_oid.hash, &type);
2424 if (!refname && errno == EISDIR) {
2425 /*
2426 * we are trying to lock foo but we used to
2427 * have foo/bar which now does not exist;
2428 * it is normal for the empty directory 'foo'
2429 * to remain.
2430 */
2431 strbuf_git_path(&orig_ref_file, "%s", orig_refname);
2432 if (remove_empty_directories(&orig_ref_file)) {
2433 last_errno = errno;
2434 if (!verify_refname_available(orig_refname, extras, skip,
2435 get_loose_refs(&ref_cache), err))
2436 strbuf_addf(err, "there are still refs under '%s'",
2437 orig_refname);
2438 goto error_return;
2439 }
2440 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
2441 lock->old_oid.hash, &type);
2442 }
2443 if (type_p)
2444 *type_p = type;
2445 if (!refname) {
2446 last_errno = errno;
2447 if (last_errno != ENOTDIR ||
2448 !verify_refname_available(orig_refname, extras, skip,
2449 get_loose_refs(&ref_cache), err))
2450 strbuf_addf(err, "unable to resolve reference %s: %s",
2451 orig_refname, strerror(last_errno));
2452
2453 goto error_return;
2454 }
2455 /*
2456 * If the ref did not exist and we are creating it, make sure
2457 * there is no existing packed ref whose name begins with our
2458 * refname, nor a packed ref whose name is a proper prefix of
2459 * our refname.
2460 */
2461 if (is_null_oid(&lock->old_oid) &&
2462 verify_refname_available(refname, extras, skip,
2463 get_packed_refs(&ref_cache), err)) {
2464 last_errno = ENOTDIR;
2465 goto error_return;
2466 }
2467
2468 lock->lk = xcalloc(1, sizeof(struct lock_file));
2469
2470 lflags = 0;
2471 if (flags & REF_NODEREF) {
2472 refname = orig_refname;
2473 lflags |= LOCK_NO_DEREF;
2474 }
2475 lock->ref_name = xstrdup(refname);
2476 lock->orig_ref_name = xstrdup(orig_refname);
2477 strbuf_git_path(&ref_file, "%s", refname);
2478
2479 retry:
2480 switch (safe_create_leading_directories_const(ref_file.buf)) {
2481 case SCLD_OK:
2482 break; /* success */
2483 case SCLD_VANISHED:
2484 if (--attempts_remaining > 0)
2485 goto retry;
2486 /* fall through */
2487 default:
2488 last_errno = errno;
2489 strbuf_addf(err, "unable to create directory for %s",
2490 ref_file.buf);
2491 goto error_return;
2492 }
2493
2494 if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {
2495 last_errno = errno;
2496 if (errno == ENOENT && --attempts_remaining > 0)
2497 /*
2498 * Maybe somebody just deleted one of the
2499 * directories leading to ref_file. Try
2500 * again:
2501 */
2502 goto retry;
2503 else {
2504 unable_to_lock_message(ref_file.buf, errno, err);
2505 goto error_return;
2506 }
2507 }
2508 if (old_sha1 && verify_lock(lock, old_sha1, mustexist, err)) {
2509 last_errno = errno;
2510 goto error_return;
2511 }
2512 goto out;
2513
2514 error_return:
2515 unlock_ref(lock);
2516 lock = NULL;
2517
2518 out:
2519 strbuf_release(&ref_file);
2520 strbuf_release(&orig_ref_file);
2521 errno = last_errno;
2522 return lock;
2523 }
2524
2525 /*
2526 * Write an entry to the packed-refs file for the specified refname.
2527 * If peeled is non-NULL, write it as the entry's peeled value.
2528 */
2529 static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2530 unsigned char *peeled)
2531 {
2532 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2533 if (peeled)
2534 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2535 }
2536
2537 /*
2538 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2539 */
2540 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2541 {
2542 enum peel_status peel_status = peel_entry(entry, 0);
2543
2544 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2545 error("internal error: %s is not a valid packed reference!",
2546 entry->name);
2547 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2548 peel_status == PEEL_PEELED ?
2549 entry->u.value.peeled.hash : NULL);
2550 return 0;
2551 }
2552
2553 /*
2554 * Lock the packed-refs file for writing. Flags is passed to
2555 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2556 * errno appropriately and return a nonzero value.
2557 */
2558 static int lock_packed_refs(int flags)
2559 {
2560 static int timeout_configured = 0;
2561 static int timeout_value = 1000;
2562
2563 struct packed_ref_cache *packed_ref_cache;
2564
2565 if (!timeout_configured) {
2566 git_config_get_int("core.packedrefstimeout", &timeout_value);
2567 timeout_configured = 1;
2568 }
2569
2570 if (hold_lock_file_for_update_timeout(
2571 &packlock, git_path("packed-refs"),
2572 flags, timeout_value) < 0)
2573 return -1;
2574 /*
2575 * Get the current packed-refs while holding the lock. If the
2576 * packed-refs file has been modified since we last read it,
2577 * this will automatically invalidate the cache and re-read
2578 * the packed-refs file.
2579 */
2580 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2581 packed_ref_cache->lock = &packlock;
2582 /* Increment the reference count to prevent it from being freed: */
2583 acquire_packed_ref_cache(packed_ref_cache);
2584 return 0;
2585 }
2586
2587 /*
2588 * Write the current version of the packed refs cache from memory to
2589 * disk. The packed-refs file must already be locked for writing (see
2590 * lock_packed_refs()). Return zero on success. On errors, set errno
2591 * and return a nonzero value
2592 */
2593 static int commit_packed_refs(void)
2594 {
2595 struct packed_ref_cache *packed_ref_cache =
2596 get_packed_ref_cache(&ref_cache);
2597 int error = 0;
2598 int save_errno = 0;
2599 FILE *out;
2600
2601 if (!packed_ref_cache->lock)
2602 die("internal error: packed-refs not locked");
2603
2604 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2605 if (!out)
2606 die_errno("unable to fdopen packed-refs descriptor");
2607
2608 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2609 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2610 0, write_packed_entry_fn, out);
2611
2612 if (commit_lock_file(packed_ref_cache->lock)) {
2613 save_errno = errno;
2614 error = -1;
2615 }
2616 packed_ref_cache->lock = NULL;
2617 release_packed_ref_cache(packed_ref_cache);
2618 errno = save_errno;
2619 return error;
2620 }
2621
2622 /*
2623 * Rollback the lockfile for the packed-refs file, and discard the
2624 * in-memory packed reference cache. (The packed-refs file will be
2625 * read anew if it is needed again after this function is called.)
2626 */
2627 static void rollback_packed_refs(void)
2628 {
2629 struct packed_ref_cache *packed_ref_cache =
2630 get_packed_ref_cache(&ref_cache);
2631
2632 if (!packed_ref_cache->lock)
2633 die("internal error: packed-refs not locked");
2634 rollback_lock_file(packed_ref_cache->lock);
2635 packed_ref_cache->lock = NULL;
2636 release_packed_ref_cache(packed_ref_cache);
2637 clear_packed_ref_cache(&ref_cache);
2638 }
2639
2640 struct ref_to_prune {
2641 struct ref_to_prune *next;
2642 unsigned char sha1[20];
2643 char name[FLEX_ARRAY];
2644 };
2645
2646 struct pack_refs_cb_data {
2647 unsigned int flags;
2648 struct ref_dir *packed_refs;
2649 struct ref_to_prune *ref_to_prune;
2650 };
2651
2652 /*
2653 * An each_ref_entry_fn that is run over loose references only. If
2654 * the loose reference can be packed, add an entry in the packed ref
2655 * cache. If the reference should be pruned, also add it to
2656 * ref_to_prune in the pack_refs_cb_data.
2657 */
2658 static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2659 {
2660 struct pack_refs_cb_data *cb = cb_data;
2661 enum peel_status peel_status;
2662 struct ref_entry *packed_entry;
2663 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2664
2665 /* ALWAYS pack tags */
2666 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2667 return 0;
2668
2669 /* Do not pack symbolic or broken refs: */
2670 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2671 return 0;
2672
2673 /* Add a packed ref cache entry equivalent to the loose entry. */
2674 peel_status = peel_entry(entry, 1);
2675 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2676 die("internal error peeling reference %s (%s)",
2677 entry->name, oid_to_hex(&entry->u.value.oid));
2678 packed_entry = find_ref(cb->packed_refs, entry->name);
2679 if (packed_entry) {
2680 /* Overwrite existing packed entry with info from loose entry */
2681 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2682 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2683 } else {
2684 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2685 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2686 add_ref(cb->packed_refs, packed_entry);
2687 }
2688 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2689
2690 /* Schedule the loose reference for pruning if requested. */
2691 if ((cb->flags & PACK_REFS_PRUNE)) {
2692 int namelen = strlen(entry->name) + 1;
2693 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2694 hashcpy(n->sha1, entry->u.value.oid.hash);
2695 strcpy(n->name, entry->name);
2696 n->next = cb->ref_to_prune;
2697 cb->ref_to_prune = n;
2698 }
2699 return 0;
2700 }
2701
2702 /*
2703 * Remove empty parents, but spare refs/ and immediate subdirs.
2704 * Note: munges *name.
2705 */
2706 static void try_remove_empty_parents(char *name)
2707 {
2708 char *p, *q;
2709 int i;
2710 p = name;
2711 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2712 while (*p && *p != '/')
2713 p++;
2714 /* tolerate duplicate slashes; see check_refname_format() */
2715 while (*p == '/')
2716 p++;
2717 }
2718 for (q = p; *q; q++)
2719 ;
2720 while (1) {
2721 while (q > p && *q != '/')
2722 q--;
2723 while (q > p && *(q-1) == '/')
2724 q--;
2725 if (q == p)
2726 break;
2727 *q = '\0';
2728 if (rmdir(git_path("%s", name)))
2729 break;
2730 }
2731 }
2732
2733 /* make sure nobody touched the ref, and unlink */
2734 static void prune_ref(struct ref_to_prune *r)
2735 {
2736 struct ref_transaction *transaction;
2737 struct strbuf err = STRBUF_INIT;
2738
2739 if (check_refname_format(r->name, 0))
2740 return;
2741
2742 transaction = ref_transaction_begin(&err);
2743 if (!transaction ||
2744 ref_transaction_delete(transaction, r->name, r->sha1,
2745 REF_ISPRUNING, NULL, &err) ||
2746 ref_transaction_commit(transaction, &err)) {
2747 ref_transaction_free(transaction);
2748 error("%s", err.buf);
2749 strbuf_release(&err);
2750 return;
2751 }
2752 ref_transaction_free(transaction);
2753 strbuf_release(&err);
2754 try_remove_empty_parents(r->name);
2755 }
2756
2757 static void prune_refs(struct ref_to_prune *r)
2758 {
2759 while (r) {
2760 prune_ref(r);
2761 r = r->next;
2762 }
2763 }
2764
2765 int pack_refs(unsigned int flags)
2766 {
2767 struct pack_refs_cb_data cbdata;
2768
2769 memset(&cbdata, 0, sizeof(cbdata));
2770 cbdata.flags = flags;
2771
2772 lock_packed_refs(LOCK_DIE_ON_ERROR);
2773 cbdata.packed_refs = get_packed_refs(&ref_cache);
2774
2775 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2776 pack_if_possible_fn, &cbdata);
2777
2778 if (commit_packed_refs())
2779 die_errno("unable to overwrite old ref-pack file");
2780
2781 prune_refs(cbdata.ref_to_prune);
2782 return 0;
2783 }
2784
2785 /*
2786 * Rewrite the packed-refs file, omitting any refs listed in
2787 * 'refnames'. On error, leave packed-refs unchanged, write an error
2788 * message to 'err', and return a nonzero value.
2789 *
2790 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2791 */
2792 static int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2793 {
2794 struct ref_dir *packed;
2795 struct string_list_item *refname;
2796 int ret, needs_repacking = 0, removed = 0;
2797
2798 assert(err);
2799
2800 /* Look for a packed ref */
2801 for_each_string_list_item(refname, refnames) {
2802 if (get_packed_ref(refname->string)) {
2803 needs_repacking = 1;
2804 break;
2805 }
2806 }
2807
2808 /* Avoid locking if we have nothing to do */
2809 if (!needs_repacking)
2810 return 0; /* no refname exists in packed refs */
2811
2812 if (lock_packed_refs(0)) {
2813 unable_to_lock_message(git_path("packed-refs"), errno, err);
2814 return -1;
2815 }
2816 packed = get_packed_refs(&ref_cache);
2817
2818 /* Remove refnames from the cache */
2819 for_each_string_list_item(refname, refnames)
2820 if (remove_entry(packed, refname->string) != -1)
2821 removed = 1;
2822 if (!removed) {
2823 /*
2824 * All packed entries disappeared while we were
2825 * acquiring the lock.
2826 */
2827 rollback_packed_refs();
2828 return 0;
2829 }
2830
2831 /* Write what remains */
2832 ret = commit_packed_refs();
2833 if (ret)
2834 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2835 strerror(errno));
2836 return ret;
2837 }
2838
2839 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2840 {
2841 assert(err);
2842
2843 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2844 /*
2845 * loose. The loose file name is the same as the
2846 * lockfile name, minus ".lock":
2847 */
2848 char *loose_filename = get_locked_file_path(lock->lk);
2849 int res = unlink_or_msg(loose_filename, err);
2850 free(loose_filename);
2851 if (res)
2852 return 1;
2853 }
2854 return 0;
2855 }
2856
2857 int delete_ref(const char *refname, const unsigned char *old_sha1,
2858 unsigned int flags)
2859 {
2860 struct ref_transaction *transaction;
2861 struct strbuf err = STRBUF_INIT;
2862
2863 transaction = ref_transaction_begin(&err);
2864 if (!transaction ||
2865 ref_transaction_delete(transaction, refname, old_sha1,
2866 flags, NULL, &err) ||
2867 ref_transaction_commit(transaction, &err)) {
2868 error("%s", err.buf);
2869 ref_transaction_free(transaction);
2870 strbuf_release(&err);
2871 return 1;
2872 }
2873 ref_transaction_free(transaction);
2874 strbuf_release(&err);
2875 return 0;
2876 }
2877
2878 int delete_refs(struct string_list *refnames)
2879 {
2880 struct strbuf err = STRBUF_INIT;
2881 int i, result = 0;
2882
2883 if (!refnames->nr)
2884 return 0;
2885
2886 result = repack_without_refs(refnames, &err);
2887 if (result) {
2888 /*
2889 * If we failed to rewrite the packed-refs file, then
2890 * it is unsafe to try to remove loose refs, because
2891 * doing so might expose an obsolete packed value for
2892 * a reference that might even point at an object that
2893 * has been garbage collected.
2894 */
2895 if (refnames->nr == 1)
2896 error(_("could not delete reference %s: %s"),
2897 refnames->items[0].string, err.buf);
2898 else
2899 error(_("could not delete references: %s"), err.buf);
2900
2901 goto out;
2902 }
2903
2904 for (i = 0; i < refnames->nr; i++) {
2905 const char *refname = refnames->items[i].string;
2906
2907 if (delete_ref(refname, NULL, 0))
2908 result |= error(_("could not remove reference %s"), refname);
2909 }
2910
2911 out:
2912 strbuf_release(&err);
2913 return result;
2914 }
2915
2916 /*
2917 * People using contrib's git-new-workdir have .git/logs/refs ->
2918 * /some/other/path/.git/logs/refs, and that may live on another device.
2919 *
2920 * IOW, to avoid cross device rename errors, the temporary renamed log must
2921 * live into logs/refs.
2922 */
2923 #define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2924
2925 static int rename_tmp_log(const char *newrefname)
2926 {
2927 int attempts_remaining = 4;
2928 struct strbuf path = STRBUF_INIT;
2929 int ret = -1;
2930
2931 retry:
2932 strbuf_reset(&path);
2933 strbuf_git_path(&path, "logs/%s", newrefname);
2934 switch (safe_create_leading_directories_const(path.buf)) {
2935 case SCLD_OK:
2936 break; /* success */
2937 case SCLD_VANISHED:
2938 if (--attempts_remaining > 0)
2939 goto retry;
2940 /* fall through */
2941 default:
2942 error("unable to create directory for %s", newrefname);
2943 goto out;
2944 }
2945
2946 if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
2947 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2948 /*
2949 * rename(a, b) when b is an existing
2950 * directory ought to result in ISDIR, but
2951 * Solaris 5.8 gives ENOTDIR. Sheesh.
2952 */
2953 if (remove_empty_directories(&path)) {
2954 error("Directory not empty: logs/%s", newrefname);
2955 goto out;
2956 }
2957 goto retry;
2958 } else if (errno == ENOENT && --attempts_remaining > 0) {
2959 /*
2960 * Maybe another process just deleted one of
2961 * the directories in the path to newrefname.
2962 * Try again from the beginning.
2963 */
2964 goto retry;
2965 } else {
2966 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2967 newrefname, strerror(errno));
2968 goto out;
2969 }
2970 }
2971 ret = 0;
2972 out:
2973 strbuf_release(&path);
2974 return ret;
2975 }
2976
2977 static int rename_ref_available(const char *oldname, const char *newname)
2978 {
2979 struct string_list skip = STRING_LIST_INIT_NODUP;
2980 struct strbuf err = STRBUF_INIT;
2981 int ret;
2982
2983 string_list_insert(&skip, oldname);
2984 ret = !verify_refname_available(newname, NULL, &skip,
2985 get_packed_refs(&ref_cache), &err)
2986 && !verify_refname_available(newname, NULL, &skip,
2987 get_loose_refs(&ref_cache), &err);
2988 if (!ret)
2989 error("%s", err.buf);
2990
2991 string_list_clear(&skip, 0);
2992 strbuf_release(&err);
2993 return ret;
2994 }
2995
2996 static int write_ref_to_lockfile(struct ref_lock *lock,
2997 const unsigned char *sha1, struct strbuf *err);
2998 static int commit_ref_update(struct ref_lock *lock,
2999 const unsigned char *sha1, const char *logmsg,
3000 int flags, struct strbuf *err);
3001
3002 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
3003 {
3004 unsigned char sha1[20], orig_sha1[20];
3005 int flag = 0, logmoved = 0;
3006 struct ref_lock *lock;
3007 struct stat loginfo;
3008 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
3009 const char *symref = NULL;
3010 struct strbuf err = STRBUF_INIT;
3011
3012 if (log && S_ISLNK(loginfo.st_mode))
3013 return error("reflog for %s is a symlink", oldrefname);
3014
3015 symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
3016 orig_sha1, &flag);
3017 if (flag & REF_ISSYMREF)
3018 return error("refname %s is a symbolic ref, renaming it is not supported",
3019 oldrefname);
3020 if (!symref)
3021 return error("refname %s not found", oldrefname);
3022
3023 if (!rename_ref_available(oldrefname, newrefname))
3024 return 1;
3025
3026 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
3027 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
3028 oldrefname, strerror(errno));
3029
3030 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
3031 error("unable to delete old %s", oldrefname);
3032 goto rollback;
3033 }
3034
3035 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
3036 delete_ref(newrefname, sha1, REF_NODEREF)) {
3037 if (errno==EISDIR) {
3038 struct strbuf path = STRBUF_INIT;
3039 int result;
3040
3041 strbuf_git_path(&path, "%s", newrefname);
3042 result = remove_empty_directories(&path);
3043 strbuf_release(&path);
3044
3045 if (result) {
3046 error("Directory not empty: %s", newrefname);
3047 goto rollback;
3048 }
3049 } else {
3050 error("unable to delete existing %s", newrefname);
3051 goto rollback;
3052 }
3053 }
3054
3055 if (log && rename_tmp_log(newrefname))
3056 goto rollback;
3057
3058 logmoved = log;
3059
3060 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);
3061 if (!lock) {
3062 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
3063 strbuf_release(&err);
3064 goto rollback;
3065 }
3066 hashcpy(lock->old_oid.hash, orig_sha1);
3067
3068 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
3069 commit_ref_update(lock, orig_sha1, logmsg, 0, &err)) {
3070 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
3071 strbuf_release(&err);
3072 goto rollback;
3073 }
3074
3075 return 0;
3076
3077 rollback:
3078 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);
3079 if (!lock) {
3080 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
3081 strbuf_release(&err);
3082 goto rollbacklog;
3083 }
3084
3085 flag = log_all_ref_updates;
3086 log_all_ref_updates = 0;
3087 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
3088 commit_ref_update(lock, orig_sha1, NULL, 0, &err)) {
3089 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
3090 strbuf_release(&err);
3091 }
3092 log_all_ref_updates = flag;
3093
3094 rollbacklog:
3095 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
3096 error("unable to restore logfile %s from %s: %s",
3097 oldrefname, newrefname, strerror(errno));
3098 if (!logmoved && log &&
3099 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
3100 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
3101 oldrefname, strerror(errno));
3102
3103 return 1;
3104 }
3105
3106 static int close_ref(struct ref_lock *lock)
3107 {
3108 if (close_lock_file(lock->lk))
3109 return -1;
3110 return 0;
3111 }
3112
3113 static int commit_ref(struct ref_lock *lock)
3114 {
3115 if (commit_lock_file(lock->lk))
3116 return -1;
3117 return 0;
3118 }
3119
3120 /*
3121 * copy the reflog message msg to buf, which has been allocated sufficiently
3122 * large, while cleaning up the whitespaces. Especially, convert LF to space,
3123 * because reflog file is one line per entry.
3124 */
3125 static int copy_msg(char *buf, const char *msg)
3126 {
3127 char *cp = buf;
3128 char c;
3129 int wasspace = 1;
3130
3131 *cp++ = '\t';
3132 while ((c = *msg++)) {
3133 if (wasspace && isspace(c))
3134 continue;
3135 wasspace = isspace(c);
3136 if (wasspace)
3137 c = ' ';
3138 *cp++ = c;
3139 }
3140 while (buf < cp && isspace(cp[-1]))
3141 cp--;
3142 *cp++ = '\n';
3143 return cp - buf;
3144 }
3145
3146 static int should_autocreate_reflog(const char *refname)
3147 {
3148 if (!log_all_ref_updates)
3149 return 0;
3150 return starts_with(refname, "refs/heads/") ||
3151 starts_with(refname, "refs/remotes/") ||
3152 starts_with(refname, "refs/notes/") ||
3153 !strcmp(refname, "HEAD");
3154 }
3155
3156 /*
3157 * Create a reflog for a ref. If force_create = 0, the reflog will
3158 * only be created for certain refs (those for which
3159 * should_autocreate_reflog returns non-zero. Otherwise, create it
3160 * regardless of the ref name. Fill in *err and return -1 on failure.
3161 */
3162 static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
3163 {
3164 int logfd, oflags = O_APPEND | O_WRONLY;
3165
3166 strbuf_git_path(logfile, "logs/%s", refname);
3167 if (force_create || should_autocreate_reflog(refname)) {
3168 if (safe_create_leading_directories(logfile->buf) < 0) {
3169 strbuf_addf(err, "unable to create directory for %s: "
3170 "%s", logfile->buf, strerror(errno));
3171 return -1;
3172 }
3173 oflags |= O_CREAT;
3174 }
3175
3176 logfd = open(logfile->buf, oflags, 0666);
3177 if (logfd < 0) {
3178 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
3179 return 0;
3180
3181 if (errno == EISDIR) {
3182 if (remove_empty_directories(logfile)) {
3183 strbuf_addf(err, "There are still logs under "
3184 "'%s'", logfile->buf);
3185 return -1;
3186 }
3187 logfd = open(logfile->buf, oflags, 0666);
3188 }
3189
3190 if (logfd < 0) {
3191 strbuf_addf(err, "unable to append to %s: %s",
3192 logfile->buf, strerror(errno));
3193 return -1;
3194 }
3195 }
3196
3197 adjust_shared_perm(logfile->buf);
3198 close(logfd);
3199 return 0;
3200 }
3201
3202
3203 int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)
3204 {
3205 int ret;
3206 struct strbuf sb = STRBUF_INIT;
3207
3208 ret = log_ref_setup(refname, &sb, err, force_create);
3209 strbuf_release(&sb);
3210 return ret;
3211 }
3212
3213 static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
3214 const unsigned char *new_sha1,
3215 const char *committer, const char *msg)
3216 {
3217 int msglen, written;
3218 unsigned maxlen, len;
3219 char *logrec;
3220
3221 msglen = msg ? strlen(msg) : 0;
3222 maxlen = strlen(committer) + msglen + 100;
3223 logrec = xmalloc(maxlen);
3224 len = sprintf(logrec, "%s %s %s\n",
3225 sha1_to_hex(old_sha1),
3226 sha1_to_hex(new_sha1),
3227 committer);
3228 if (msglen)
3229 len += copy_msg(logrec + len - 1, msg) - 1;
3230
3231 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
3232 free(logrec);
3233 if (written != len)
3234 return -1;
3235
3236 return 0;
3237 }
3238
3239 static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
3240 const unsigned char *new_sha1, const char *msg,
3241 struct strbuf *logfile, int flags,
3242 struct strbuf *err)
3243 {
3244 int logfd, result, oflags = O_APPEND | O_WRONLY;
3245
3246 if (log_all_ref_updates < 0)
3247 log_all_ref_updates = !is_bare_repository();
3248
3249 result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
3250
3251 if (result)
3252 return result;
3253
3254 logfd = open(logfile->buf, oflags);
3255 if (logfd < 0)
3256 return 0;
3257 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
3258 git_committer_info(0), msg);
3259 if (result) {
3260 strbuf_addf(err, "unable to append to %s: %s", logfile->buf,
3261 strerror(errno));
3262 close(logfd);
3263 return -1;
3264 }
3265 if (close(logfd)) {
3266 strbuf_addf(err, "unable to append to %s: %s", logfile->buf,
3267 strerror(errno));
3268 return -1;
3269 }
3270 return 0;
3271 }
3272
3273 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
3274 const unsigned char *new_sha1, const char *msg,
3275 int flags, struct strbuf *err)
3276 {
3277 struct strbuf sb = STRBUF_INIT;
3278 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
3279 err);
3280 strbuf_release(&sb);
3281 return ret;
3282 }
3283
3284 int is_branch(const char *refname)
3285 {
3286 return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
3287 }
3288
3289 /*
3290 * Write sha1 into the open lockfile, then close the lockfile. On
3291 * errors, rollback the lockfile, fill in *err and
3292 * return -1.
3293 */
3294 static int write_ref_to_lockfile(struct ref_lock *lock,
3295 const unsigned char *sha1, struct strbuf *err)
3296 {
3297 static char term = '\n';
3298 struct object *o;
3299
3300 o = parse_object(sha1);
3301 if (!o) {
3302 strbuf_addf(err,
3303 "Trying to write ref %s with nonexistent object %s",
3304 lock->ref_name, sha1_to_hex(sha1));
3305 unlock_ref(lock);
3306 return -1;
3307 }
3308 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
3309 strbuf_addf(err,
3310 "Trying to write non-commit object %s to branch %s",
3311 sha1_to_hex(sha1), lock->ref_name);
3312 unlock_ref(lock);
3313 return -1;
3314 }
3315 if (write_in_full(lock->lk->fd, sha1_to_hex(sha1), 40) != 40 ||
3316 write_in_full(lock->lk->fd, &term, 1) != 1 ||
3317 close_ref(lock) < 0) {
3318 strbuf_addf(err,
3319 "Couldn't write %s", lock->lk->filename.buf);
3320 unlock_ref(lock);
3321 return -1;
3322 }
3323 return 0;
3324 }
3325
3326 /*
3327 * Commit a change to a loose reference that has already been written
3328 * to the loose reference lockfile. Also update the reflogs if
3329 * necessary, using the specified lockmsg (which can be NULL).
3330 */
3331 static int commit_ref_update(struct ref_lock *lock,
3332 const unsigned char *sha1, const char *logmsg,
3333 int flags, struct strbuf *err)
3334 {
3335 clear_loose_ref_cache(&ref_cache);
3336 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0 ||
3337 (strcmp(lock->ref_name, lock->orig_ref_name) &&
3338 log_ref_write(lock->orig_ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0)) {
3339 char *old_msg = strbuf_detach(err, NULL);
3340 strbuf_addf(err, "Cannot update the ref '%s': %s",
3341 lock->ref_name, old_msg);
3342 free(old_msg);
3343 unlock_ref(lock);
3344 return -1;
3345 }
3346 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
3347 /*
3348 * Special hack: If a branch is updated directly and HEAD
3349 * points to it (may happen on the remote side of a push
3350 * for example) then logically the HEAD reflog should be
3351 * updated too.
3352 * A generic solution implies reverse symref information,
3353 * but finding all symrefs pointing to the given branch
3354 * would be rather costly for this rare event (the direct
3355 * update of a branch) to be worth it. So let's cheat and
3356 * check with HEAD only which should cover 99% of all usage
3357 * scenarios (even 100% of the default ones).
3358 */
3359 unsigned char head_sha1[20];
3360 int head_flag;
3361 const char *head_ref;
3362 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3363 head_sha1, &head_flag);
3364 if (head_ref && (head_flag & REF_ISSYMREF) &&
3365 !strcmp(head_ref, lock->ref_name)) {
3366 struct strbuf log_err = STRBUF_INIT;
3367 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
3368 logmsg, 0, &log_err)) {
3369 error("%s", log_err.buf);
3370 strbuf_release(&log_err);
3371 }
3372 }
3373 }
3374 if (commit_ref(lock)) {
3375 error("Couldn't set %s", lock->ref_name);
3376 unlock_ref(lock);
3377 return -1;
3378 }
3379
3380 unlock_ref(lock);
3381 return 0;
3382 }
3383
3384 int create_symref(const char *ref_target, const char *refs_heads_master,
3385 const char *logmsg)
3386 {
3387 char *lockpath = NULL;
3388 char ref[1000];
3389 int fd, len, written;
3390 char *git_HEAD = git_pathdup("%s", ref_target);
3391 unsigned char old_sha1[20], new_sha1[20];
3392 struct strbuf err = STRBUF_INIT;
3393
3394 if (logmsg && read_ref(ref_target, old_sha1))
3395 hashclr(old_sha1);
3396
3397 if (safe_create_leading_directories(git_HEAD) < 0)
3398 return error("unable to create directory for %s", git_HEAD);
3399
3400 #ifndef NO_SYMLINK_HEAD
3401 if (prefer_symlink_refs) {
3402 unlink(git_HEAD);
3403 if (!symlink(refs_heads_master, git_HEAD))
3404 goto done;
3405 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
3406 }
3407 #endif
3408
3409 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
3410 if (sizeof(ref) <= len) {
3411 error("refname too long: %s", refs_heads_master);
3412 goto error_free_return;
3413 }
3414 lockpath = mkpathdup("%s.lock", git_HEAD);
3415 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
3416 if (fd < 0) {
3417 error("Unable to open %s for writing", lockpath);
3418 goto error_free_return;
3419 }
3420 written = write_in_full(fd, ref, len);
3421 if (close(fd) != 0 || written != len) {
3422 error("Unable to write to %s", lockpath);
3423 goto error_unlink_return;
3424 }
3425 if (rename(lockpath, git_HEAD) < 0) {
3426 error("Unable to create %s", git_HEAD);
3427 goto error_unlink_return;
3428 }
3429 if (adjust_shared_perm(git_HEAD)) {
3430 error("Unable to fix permissions on %s", lockpath);
3431 error_unlink_return:
3432 unlink_or_warn(lockpath);
3433 error_free_return:
3434 free(lockpath);
3435 free(git_HEAD);
3436 return -1;
3437 }
3438 free(lockpath);
3439
3440 #ifndef NO_SYMLINK_HEAD
3441 done:
3442 #endif
3443 if (logmsg && !read_ref(refs_heads_master, new_sha1) &&
3444 log_ref_write(ref_target, old_sha1, new_sha1, logmsg, 0, &err)) {
3445 error("%s", err.buf);
3446 strbuf_release(&err);
3447 }
3448
3449 free(git_HEAD);
3450 return 0;
3451 }
3452
3453 struct read_ref_at_cb {
3454 const char *refname;
3455 unsigned long at_time;
3456 int cnt;
3457 int reccnt;
3458 unsigned char *sha1;
3459 int found_it;
3460
3461 unsigned char osha1[20];
3462 unsigned char nsha1[20];
3463 int tz;
3464 unsigned long date;
3465 char **msg;
3466 unsigned long *cutoff_time;
3467 int *cutoff_tz;
3468 int *cutoff_cnt;
3469 };
3470
3471 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
3472 const char *email, unsigned long timestamp, int tz,
3473 const char *message, void *cb_data)
3474 {
3475 struct read_ref_at_cb *cb = cb_data;
3476
3477 cb->reccnt++;
3478 cb->tz = tz;
3479 cb->date = timestamp;
3480
3481 if (timestamp <= cb->at_time || cb->cnt == 0) {
3482 if (cb->msg)
3483 *cb->msg = xstrdup(message);
3484 if (cb->cutoff_time)
3485 *cb->cutoff_time = timestamp;
3486 if (cb->cutoff_tz)
3487 *cb->cutoff_tz = tz;
3488 if (cb->cutoff_cnt)
3489 *cb->cutoff_cnt = cb->reccnt - 1;
3490 /*
3491 * we have not yet updated cb->[n|o]sha1 so they still
3492 * hold the values for the previous record.
3493 */
3494 if (!is_null_sha1(cb->osha1)) {
3495 hashcpy(cb->sha1, nsha1);
3496 if (hashcmp(cb->osha1, nsha1))
3497 warning("Log for ref %s has gap after %s.",
3498 cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
3499 }
3500 else if (cb->date == cb->at_time)
3501 hashcpy(cb->sha1, nsha1);
3502 else if (hashcmp(nsha1, cb->sha1))
3503 warning("Log for ref %s unexpectedly ended on %s.",
3504 cb->refname, show_date(cb->date, cb->tz,
3505 DATE_MODE(RFC2822)));
3506 hashcpy(cb->osha1, osha1);
3507 hashcpy(cb->nsha1, nsha1);
3508 cb->found_it = 1;
3509 return 1;
3510 }
3511 hashcpy(cb->osha1, osha1);
3512 hashcpy(cb->nsha1, nsha1);
3513 if (cb->cnt > 0)
3514 cb->cnt--;
3515 return 0;
3516 }
3517
3518 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
3519 const char *email, unsigned long timestamp,
3520 int tz, const char *message, void *cb_data)
3521 {
3522 struct read_ref_at_cb *cb = cb_data;
3523
3524 if (cb->msg)
3525 *cb->msg = xstrdup(message);
3526 if (cb->cutoff_time)
3527 *cb->cutoff_time = timestamp;
3528 if (cb->cutoff_tz)
3529 *cb->cutoff_tz = tz;
3530 if (cb->cutoff_cnt)
3531 *cb->cutoff_cnt = cb->reccnt;
3532 hashcpy(cb->sha1, osha1);
3533 if (is_null_sha1(cb->sha1))
3534 hashcpy(cb->sha1, nsha1);
3535 /* We just want the first entry */
3536 return 1;
3537 }
3538
3539 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
3540 unsigned char *sha1, char **msg,
3541 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
3542 {
3543 struct read_ref_at_cb cb;
3544
3545 memset(&cb, 0, sizeof(cb));
3546 cb.refname = refname;
3547 cb.at_time = at_time;
3548 cb.cnt = cnt;
3549 cb.msg = msg;
3550 cb.cutoff_time = cutoff_time;
3551 cb.cutoff_tz = cutoff_tz;
3552 cb.cutoff_cnt = cutoff_cnt;
3553 cb.sha1 = sha1;
3554
3555 for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
3556
3557 if (!cb.reccnt) {
3558 if (flags & GET_SHA1_QUIETLY)
3559 exit(128);
3560 else
3561 die("Log for %s is empty.", refname);
3562 }
3563 if (cb.found_it)
3564 return 0;
3565
3566 for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
3567
3568 return 1;
3569 }
3570
3571 int reflog_exists(const char *refname)
3572 {
3573 struct stat st;
3574
3575 return !lstat(git_path("logs/%s", refname), &st) &&
3576 S_ISREG(st.st_mode);
3577 }
3578
3579 int delete_reflog(const char *refname)
3580 {
3581 return remove_path(git_path("logs/%s", refname));
3582 }
3583
3584 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3585 {
3586 unsigned char osha1[20], nsha1[20];
3587 char *email_end, *message;
3588 unsigned long timestamp;
3589 int tz;
3590
3591 /* old SP new SP name <email> SP time TAB msg LF */
3592 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3593 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3594 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3595 !(email_end = strchr(sb->buf + 82, '>')) ||
3596 email_end[1] != ' ' ||
3597 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3598 !message || message[0] != ' ' ||
3599 (message[1] != '+' && message[1] != '-') ||
3600 !isdigit(message[2]) || !isdigit(message[3]) ||
3601 !isdigit(message[4]) || !isdigit(message[5]))
3602 return 0; /* corrupt? */
3603 email_end[1] = '\0';
3604 tz = strtol(message + 1, NULL, 10);
3605 if (message[6] != '\t')
3606 message += 6;
3607 else
3608 message += 7;
3609 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3610 }
3611
3612 static char *find_beginning_of_line(char *bob, char *scan)
3613 {
3614 while (bob < scan && *(--scan) != '\n')
3615 ; /* keep scanning backwards */
3616 /*
3617 * Return either beginning of the buffer, or LF at the end of
3618 * the previous line.
3619 */
3620 return scan;
3621 }
3622
3623 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3624 {
3625 struct strbuf sb = STRBUF_INIT;
3626 FILE *logfp;
3627 long pos;
3628 int ret = 0, at_tail = 1;
3629
3630 logfp = fopen(git_path("logs/%s", refname), "r");
3631 if (!logfp)
3632 return -1;
3633
3634 /* Jump to the end */
3635 if (fseek(logfp, 0, SEEK_END) < 0)
3636 return error("cannot seek back reflog for %s: %s",
3637 refname, strerror(errno));
3638 pos = ftell(logfp);
3639 while (!ret && 0 < pos) {
3640 int cnt;
3641 size_t nread;
3642 char buf[BUFSIZ];
3643 char *endp, *scanp;
3644
3645 /* Fill next block from the end */
3646 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3647 if (fseek(logfp, pos - cnt, SEEK_SET))
3648 return error("cannot seek back reflog for %s: %s",
3649 refname, strerror(errno));
3650 nread = fread(buf, cnt, 1, logfp);
3651 if (nread != 1)
3652 return error("cannot read %d bytes from reflog for %s: %s",
3653 cnt, refname, strerror(errno));
3654 pos -= cnt;
3655
3656 scanp = endp = buf + cnt;
3657 if (at_tail && scanp[-1] == '\n')
3658 /* Looking at the final LF at the end of the file */
3659 scanp--;
3660 at_tail = 0;
3661
3662 while (buf < scanp) {
3663 /*
3664 * terminating LF of the previous line, or the beginning
3665 * of the buffer.
3666 */
3667 char *bp;
3668
3669 bp = find_beginning_of_line(buf, scanp);
3670
3671 if (*bp == '\n') {
3672 /*
3673 * The newline is the end of the previous line,
3674 * so we know we have complete line starting
3675 * at (bp + 1). Prefix it onto any prior data
3676 * we collected for the line and process it.
3677 */
3678 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3679 scanp = bp;
3680 endp = bp + 1;
3681 ret = show_one_reflog_ent(&sb, fn, cb_data);
3682 strbuf_reset(&sb);
3683 if (ret)
3684 break;
3685 } else if (!pos) {
3686 /*
3687 * We are at the start of the buffer, and the
3688 * start of the file; there is no previous
3689 * line, and we have everything for this one.
3690 * Process it, and we can end the loop.
3691 */
3692 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3693 ret = show_one_reflog_ent(&sb, fn, cb_data);
3694 strbuf_reset(&sb);
3695 break;
3696 }
3697
3698 if (bp == buf) {
3699 /*
3700 * We are at the start of the buffer, and there
3701 * is more file to read backwards. Which means
3702 * we are in the middle of a line. Note that we
3703 * may get here even if *bp was a newline; that
3704 * just means we are at the exact end of the
3705 * previous line, rather than some spot in the
3706 * middle.
3707 *
3708 * Save away what we have to be combined with
3709 * the data from the next read.
3710 */
3711 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3712 break;
3713 }
3714 }
3715
3716 }
3717 if (!ret && sb.len)
3718 die("BUG: reverse reflog parser had leftover data");
3719
3720 fclose(logfp);
3721 strbuf_release(&sb);
3722 return ret;
3723 }
3724
3725 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3726 {
3727 FILE *logfp;
3728 struct strbuf sb = STRBUF_INIT;
3729 int ret = 0;
3730
3731 logfp = fopen(git_path("logs/%s", refname), "r");
3732 if (!logfp)
3733 return -1;
3734
3735 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3736 ret = show_one_reflog_ent(&sb, fn, cb_data);
3737 fclose(logfp);
3738 strbuf_release(&sb);
3739 return ret;
3740 }
3741 /*
3742 * Call fn for each reflog in the namespace indicated by name. name
3743 * must be empty or end with '/'. Name will be used as a scratch
3744 * space, but its contents will be restored before return.
3745 */
3746 static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3747 {
3748 DIR *d = opendir(git_path("logs/%s", name->buf));
3749 int retval = 0;
3750 struct dirent *de;
3751 int oldlen = name->len;
3752
3753 if (!d)
3754 return name->len ? errno : 0;
3755
3756 while ((de = readdir(d)) != NULL) {
3757 struct stat st;
3758
3759 if (de->d_name[0] == '.')
3760 continue;
3761 if (ends_with(de->d_name, ".lock"))
3762 continue;
3763 strbuf_addstr(name, de->d_name);
3764 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3765 ; /* silently ignore */
3766 } else {
3767 if (S_ISDIR(st.st_mode)) {
3768 strbuf_addch(name, '/');
3769 retval = do_for_each_reflog(name, fn, cb_data);
3770 } else {
3771 struct object_id oid;
3772
3773 if (read_ref_full(name->buf, 0, oid.hash, NULL))
3774 retval = error("bad ref for %s", name->buf);
3775 else
3776 retval = fn(name->buf, &oid, 0, cb_data);
3777 }
3778 if (retval)
3779 break;
3780 }
3781 strbuf_setlen(name, oldlen);
3782 }
3783 closedir(d);
3784 return retval;
3785 }
3786
3787 int for_each_reflog(each_ref_fn fn, void *cb_data)
3788 {
3789 int retval;
3790 struct strbuf name;
3791 strbuf_init(&name, PATH_MAX);
3792 retval = do_for_each_reflog(&name, fn, cb_data);
3793 strbuf_release(&name);
3794 return retval;
3795 }
3796
3797 /**
3798 * Information needed for a single ref update. Set new_sha1 to the new
3799 * value or to null_sha1 to delete the ref. To check the old value
3800 * while the ref is locked, set (flags & REF_HAVE_OLD) and set
3801 * old_sha1 to the old value, or to null_sha1 to ensure the ref does
3802 * not exist before update.
3803 */
3804 struct ref_update {
3805 /*
3806 * If (flags & REF_HAVE_NEW), set the reference to this value:
3807 */
3808 unsigned char new_sha1[20];
3809 /*
3810 * If (flags & REF_HAVE_OLD), check that the reference
3811 * previously had this value:
3812 */
3813 unsigned char old_sha1[20];
3814 /*
3815 * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
3816 * REF_DELETING, and REF_ISPRUNING:
3817 */
3818 unsigned int flags;
3819 struct ref_lock *lock;
3820 int type;
3821 char *msg;
3822 const char refname[FLEX_ARRAY];
3823 };
3824
3825 /*
3826 * Transaction states.
3827 * OPEN: The transaction is in a valid state and can accept new updates.
3828 * An OPEN transaction can be committed.
3829 * CLOSED: A closed transaction is no longer active and no other operations
3830 * than free can be used on it in this state.
3831 * A transaction can either become closed by successfully committing
3832 * an active transaction or if there is a failure while building
3833 * the transaction thus rendering it failed/inactive.
3834 */
3835 enum ref_transaction_state {
3836 REF_TRANSACTION_OPEN = 0,
3837 REF_TRANSACTION_CLOSED = 1
3838 };
3839
3840 /*
3841 * Data structure for holding a reference transaction, which can
3842 * consist of checks and updates to multiple references, carried out
3843 * as atomically as possible. This structure is opaque to callers.
3844 */
3845 struct ref_transaction {
3846 struct ref_update **updates;
3847 size_t alloc;
3848 size_t nr;
3849 enum ref_transaction_state state;
3850 };
3851
3852 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
3853 {
3854 assert(err);
3855
3856 return xcalloc(1, sizeof(struct ref_transaction));
3857 }
3858
3859 void ref_transaction_free(struct ref_transaction *transaction)
3860 {
3861 int i;
3862
3863 if (!transaction)
3864 return;
3865
3866 for (i = 0; i < transaction->nr; i++) {
3867 free(transaction->updates[i]->msg);
3868 free(transaction->updates[i]);
3869 }
3870 free(transaction->updates);
3871 free(transaction);
3872 }
3873
3874 static struct ref_update *add_update(struct ref_transaction *transaction,
3875 const char *refname)
3876 {
3877 size_t len = strlen(refname);
3878 struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
3879
3880 strcpy((char *)update->refname, refname);
3881 ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
3882 transaction->updates[transaction->nr++] = update;
3883 return update;
3884 }
3885
3886 int ref_transaction_update(struct ref_transaction *transaction,
3887 const char *refname,
3888 const unsigned char *new_sha1,
3889 const unsigned char *old_sha1,
3890 unsigned int flags, const char *msg,
3891 struct strbuf *err)
3892 {
3893 struct ref_update *update;
3894
3895 assert(err);
3896
3897 if (transaction->state != REF_TRANSACTION_OPEN)
3898 die("BUG: update called for transaction that is not open");
3899
3900 if (new_sha1 && !is_null_sha1(new_sha1) &&
3901 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
3902 strbuf_addf(err, "refusing to update ref with bad name %s",
3903 refname);
3904 return -1;
3905 }
3906
3907 update = add_update(transaction, refname);
3908 if (new_sha1) {
3909 hashcpy(update->new_sha1, new_sha1);
3910 flags |= REF_HAVE_NEW;
3911 }
3912 if (old_sha1) {
3913 hashcpy(update->old_sha1, old_sha1);
3914 flags |= REF_HAVE_OLD;
3915 }
3916 update->flags = flags;
3917 if (msg)
3918 update->msg = xstrdup(msg);
3919 return 0;
3920 }
3921
3922 int ref_transaction_create(struct ref_transaction *transaction,
3923 const char *refname,
3924 const unsigned char *new_sha1,
3925 unsigned int flags, const char *msg,
3926 struct strbuf *err)
3927 {
3928 if (!new_sha1 || is_null_sha1(new_sha1))
3929 die("BUG: create called without valid new_sha1");
3930 return ref_transaction_update(transaction, refname, new_sha1,
3931 null_sha1, flags, msg, err);
3932 }
3933
3934 int ref_transaction_delete(struct ref_transaction *transaction,
3935 const char *refname,
3936 const unsigned char *old_sha1,
3937 unsigned int flags, const char *msg,
3938 struct strbuf *err)
3939 {
3940 if (old_sha1 && is_null_sha1(old_sha1))
3941 die("BUG: delete called with old_sha1 set to zeros");
3942 return ref_transaction_update(transaction, refname,
3943 null_sha1, old_sha1,
3944 flags, msg, err);
3945 }