]>
Commit | Line | Data |
---|---|---|
67be7c5a | 1 | #include "../cache.h" |
44c2339e | 2 | #include "../config.h" |
67be7c5a MH |
3 | #include "../refs.h" |
4 | #include "refs-internal.h" | |
67be7c5a MH |
5 | #include "packed-backend.h" |
6 | #include "../iterator.h" | |
7 | #include "../lockfile.h" | |
8 | ||
5b633610 MH |
9 | enum mmap_strategy { |
10 | /* | |
11 | * Don't use mmap() at all for reading `packed-refs`. | |
12 | */ | |
13 | MMAP_NONE, | |
14 | ||
15 | /* | |
16 | * Can use mmap() for reading `packed-refs`, but the file must | |
17 | * not remain mmapped. This is the usual option on Windows, | |
18 | * where you cannot rename a new version of a file onto a file | |
19 | * that is currently mmapped. | |
20 | */ | |
21 | MMAP_TEMPORARY, | |
22 | ||
23 | /* | |
24 | * It is OK to leave the `packed-refs` file mmapped while | |
25 | * arbitrary other code is running. | |
26 | */ | |
27 | MMAP_OK | |
28 | }; | |
29 | ||
30 | #if defined(NO_MMAP) | |
31 | static enum mmap_strategy mmap_strategy = MMAP_NONE; | |
32 | #elif defined(MMAP_PREVENTS_DELETE) | |
33 | static enum mmap_strategy mmap_strategy = MMAP_TEMPORARY; | |
34 | #else | |
35 | static enum mmap_strategy mmap_strategy = MMAP_OK; | |
36 | #endif | |
37 | ||
f0a7dc86 MH |
38 | struct packed_ref_store; |
39 | ||
67be7c5a | 40 | struct packed_ref_cache { |
f0a7dc86 MH |
41 | /* |
42 | * A back-pointer to the packed_ref_store with which this | |
43 | * cache is associated: | |
44 | */ | |
45 | struct packed_ref_store *refs; | |
46 | ||
5b633610 MH |
47 | /* Is the `packed-refs` file currently mmapped? */ |
48 | int mmapped; | |
49 | ||
50 | /* | |
02b920f3 MH |
51 | * The contents of the `packed-refs` file. If the file was |
52 | * already sorted, this points at the mmapped contents of the | |
53 | * file. If not, this points at heap-allocated memory | |
54 | * containing the contents, sorted. If there were no contents | |
55 | * (e.g., because the file didn't exist), `buf` and `eof` are | |
56 | * both NULL. | |
5b633610 MH |
57 | */ |
58 | char *buf, *eof; | |
59 | ||
60 | /* The size of the header line, if any; otherwise, 0: */ | |
61 | size_t header_len; | |
62 | ||
daa45408 MH |
63 | /* |
64 | * What is the peeled state of this cache? (This is usually | |
65 | * determined from the header of the "packed-refs" file.) | |
66 | */ | |
67 | enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled; | |
68 | ||
67be7c5a MH |
69 | /* |
70 | * Count of references to the data structure in this instance, | |
71 | * including the pointer from files_ref_store::packed if any. | |
72 | * The data will not be freed as long as the reference count | |
73 | * is nonzero. | |
74 | */ | |
75 | unsigned int referrers; | |
76 | ||
77 | /* The metadata from when this packed-refs cache was read */ | |
78 | struct stat_validity validity; | |
79 | }; | |
80 | ||
67be7c5a MH |
81 | /* |
82 | * A container for `packed-refs`-related data. It is not (yet) a | |
83 | * `ref_store`. | |
84 | */ | |
85 | struct packed_ref_store { | |
e0cc8ac8 MH |
86 | struct ref_store base; |
87 | ||
67be7c5a MH |
88 | unsigned int store_flags; |
89 | ||
90 | /* The path of the "packed-refs" file: */ | |
91 | char *path; | |
92 | ||
93 | /* | |
94 | * A cache of the values read from the `packed-refs` file, if | |
95 | * it might still be current; otherwise, NULL. | |
96 | */ | |
97 | struct packed_ref_cache *cache; | |
98 | ||
99 | /* | |
100 | * Lock used for the "packed-refs" file. Note that this (and | |
101 | * thus the enclosing `packed_ref_store`) must not be freed. | |
102 | */ | |
103 | struct lock_file lock; | |
42dfa7ec MH |
104 | |
105 | /* | |
106 | * Temporary file used when rewriting new contents to the | |
107 | * "packed-refs" file. Note that this (and thus the enclosing | |
108 | * `packed_ref_store`) must not be freed. | |
109 | */ | |
110 | struct tempfile tempfile; | |
67be7c5a MH |
111 | }; |
112 | ||
14b3c344 MH |
113 | /* |
114 | * Increment the reference count of *packed_refs. | |
115 | */ | |
116 | static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs) | |
117 | { | |
118 | packed_refs->referrers++; | |
119 | } | |
120 | ||
5b633610 MH |
121 | /* |
122 | * If the buffer in `packed_refs` is active, then either munmap the | |
123 | * memory and close the file, or free the memory. Then set the buffer | |
124 | * pointers to NULL. | |
125 | */ | |
126 | static void release_packed_ref_buffer(struct packed_ref_cache *packed_refs) | |
127 | { | |
128 | if (packed_refs->mmapped) { | |
129 | if (munmap(packed_refs->buf, | |
130 | packed_refs->eof - packed_refs->buf)) | |
131 | die_errno("error ummapping packed-refs file %s", | |
132 | packed_refs->refs->path); | |
133 | packed_refs->mmapped = 0; | |
134 | } else { | |
135 | free(packed_refs->buf); | |
136 | } | |
137 | packed_refs->buf = packed_refs->eof = NULL; | |
138 | packed_refs->header_len = 0; | |
139 | } | |
140 | ||
14b3c344 MH |
141 | /* |
142 | * Decrease the reference count of *packed_refs. If it goes to zero, | |
143 | * free *packed_refs and return true; otherwise return false. | |
144 | */ | |
145 | static int release_packed_ref_cache(struct packed_ref_cache *packed_refs) | |
146 | { | |
147 | if (!--packed_refs->referrers) { | |
14b3c344 | 148 | stat_validity_clear(&packed_refs->validity); |
5b633610 | 149 | release_packed_ref_buffer(packed_refs); |
14b3c344 MH |
150 | free(packed_refs); |
151 | return 1; | |
152 | } else { | |
153 | return 0; | |
154 | } | |
155 | } | |
156 | ||
e0cc8ac8 MH |
157 | struct ref_store *packed_ref_store_create(const char *path, |
158 | unsigned int store_flags) | |
67be7c5a MH |
159 | { |
160 | struct packed_ref_store *refs = xcalloc(1, sizeof(*refs)); | |
e0cc8ac8 | 161 | struct ref_store *ref_store = (struct ref_store *)refs; |
67be7c5a | 162 | |
e0cc8ac8 | 163 | base_ref_store_init(ref_store, &refs_be_packed); |
67be7c5a | 164 | refs->store_flags = store_flags; |
e0cc8ac8 | 165 | |
67be7c5a | 166 | refs->path = xstrdup(path); |
e0cc8ac8 | 167 | return ref_store; |
67be7c5a MH |
168 | } |
169 | ||
e0cc8ac8 MH |
170 | /* |
171 | * Downcast `ref_store` to `packed_ref_store`. Die if `ref_store` is | |
172 | * not a `packed_ref_store`. Also die if `packed_ref_store` doesn't | |
173 | * support at least the flags specified in `required_flags`. `caller` | |
174 | * is used in any necessary error messages. | |
175 | */ | |
176 | static struct packed_ref_store *packed_downcast(struct ref_store *ref_store, | |
177 | unsigned int required_flags, | |
178 | const char *caller) | |
179 | { | |
180 | struct packed_ref_store *refs; | |
181 | ||
182 | if (ref_store->be != &refs_be_packed) | |
183 | die("BUG: ref_store is type \"%s\" not \"packed\" in %s", | |
184 | ref_store->be->name, caller); | |
185 | ||
186 | refs = (struct packed_ref_store *)ref_store; | |
187 | ||
188 | if ((refs->store_flags & required_flags) != required_flags) | |
189 | die("BUG: unallowed operation (%s), requires %x, has %x\n", | |
190 | caller, required_flags, refs->store_flags); | |
191 | ||
192 | return refs; | |
193 | } | |
194 | ||
67be7c5a MH |
195 | static void clear_packed_ref_cache(struct packed_ref_store *refs) |
196 | { | |
197 | if (refs->cache) { | |
198 | struct packed_ref_cache *cache = refs->cache; | |
199 | ||
67be7c5a MH |
200 | refs->cache = NULL; |
201 | release_packed_ref_cache(cache); | |
202 | } | |
203 | } | |
204 | ||
735267aa MH |
205 | static NORETURN void die_unterminated_line(const char *path, |
206 | const char *p, size_t len) | |
207 | { | |
208 | if (len < 80) | |
209 | die("unterminated line in %s: %.*s", path, (int)len, p); | |
210 | else | |
211 | die("unterminated line in %s: %.75s...", path, p); | |
212 | } | |
213 | ||
214 | static NORETURN void die_invalid_line(const char *path, | |
215 | const char *p, size_t len) | |
216 | { | |
217 | const char *eol = memchr(p, '\n', len); | |
218 | ||
219 | if (!eol) | |
220 | die_unterminated_line(path, p, len); | |
221 | else if (eol - p < 80) | |
222 | die("unexpected line in %s: %.*s", path, (int)(eol - p), p); | |
223 | else | |
224 | die("unexpected line in %s: %.75s...", path, p); | |
225 | ||
226 | } | |
227 | ||
a6e19bcd MH |
228 | /* |
229 | * This value is set in `base.flags` if the peeled value of the | |
230 | * current reference is known. In that case, `peeled` contains the | |
231 | * correct peeled value for the reference, which might be `null_sha1` | |
232 | * if the reference is not a tag or if it is broken. | |
233 | */ | |
234 | #define REF_KNOWS_PEELED 0x40 | |
235 | ||
9cfb3dc0 MH |
236 | /* |
237 | * An iterator over a packed-refs file that is currently mmapped. | |
238 | */ | |
239 | struct mmapped_ref_iterator { | |
240 | struct ref_iterator base; | |
241 | ||
242 | struct packed_ref_cache *packed_refs; | |
243 | ||
244 | /* The current position in the mmapped file: */ | |
245 | const char *pos; | |
246 | ||
247 | /* The end of the mmapped file: */ | |
248 | const char *eof; | |
249 | ||
250 | struct object_id oid, peeled; | |
251 | ||
252 | struct strbuf refname_buf; | |
253 | }; | |
254 | ||
255 | static int mmapped_ref_iterator_advance(struct ref_iterator *ref_iterator) | |
256 | { | |
257 | struct mmapped_ref_iterator *iter = | |
258 | (struct mmapped_ref_iterator *)ref_iterator; | |
259 | const char *p = iter->pos, *eol; | |
260 | ||
261 | strbuf_reset(&iter->refname_buf); | |
262 | ||
263 | if (iter->pos == iter->eof) | |
264 | return ref_iterator_abort(ref_iterator); | |
265 | ||
266 | iter->base.flags = REF_ISPACKED; | |
267 | ||
268 | if (iter->eof - p < GIT_SHA1_HEXSZ + 2 || | |
269 | parse_oid_hex(p, &iter->oid, &p) || | |
270 | !isspace(*p++)) | |
271 | die_invalid_line(iter->packed_refs->refs->path, | |
272 | iter->pos, iter->eof - iter->pos); | |
273 | ||
274 | eol = memchr(p, '\n', iter->eof - p); | |
275 | if (!eol) | |
276 | die_unterminated_line(iter->packed_refs->refs->path, | |
277 | iter->pos, iter->eof - iter->pos); | |
278 | ||
279 | strbuf_add(&iter->refname_buf, p, eol - p); | |
280 | iter->base.refname = iter->refname_buf.buf; | |
281 | ||
282 | if (check_refname_format(iter->base.refname, REFNAME_ALLOW_ONELEVEL)) { | |
283 | if (!refname_is_safe(iter->base.refname)) | |
284 | die("packed refname is dangerous: %s", | |
285 | iter->base.refname); | |
286 | oidclr(&iter->oid); | |
287 | iter->base.flags |= REF_BAD_NAME | REF_ISBROKEN; | |
288 | } | |
289 | if (iter->packed_refs->peeled == PEELED_FULLY || | |
290 | (iter->packed_refs->peeled == PEELED_TAGS && | |
291 | starts_with(iter->base.refname, "refs/tags/"))) | |
292 | iter->base.flags |= REF_KNOWS_PEELED; | |
293 | ||
294 | iter->pos = eol + 1; | |
295 | ||
296 | if (iter->pos < iter->eof && *iter->pos == '^') { | |
297 | p = iter->pos + 1; | |
298 | if (iter->eof - p < GIT_SHA1_HEXSZ + 1 || | |
299 | parse_oid_hex(p, &iter->peeled, &p) || | |
300 | *p++ != '\n') | |
301 | die_invalid_line(iter->packed_refs->refs->path, | |
302 | iter->pos, iter->eof - iter->pos); | |
303 | iter->pos = p; | |
304 | ||
305 | /* | |
306 | * Regardless of what the file header said, we | |
81b9b5ae MH |
307 | * definitely know the value of *this* reference. But |
308 | * we suppress it if the reference is broken: | |
9cfb3dc0 | 309 | */ |
81b9b5ae MH |
310 | if ((iter->base.flags & REF_ISBROKEN)) { |
311 | oidclr(&iter->peeled); | |
312 | iter->base.flags &= ~REF_KNOWS_PEELED; | |
313 | } else { | |
314 | iter->base.flags |= REF_KNOWS_PEELED; | |
315 | } | |
9cfb3dc0 MH |
316 | } else { |
317 | oidclr(&iter->peeled); | |
318 | } | |
319 | ||
320 | return ITER_OK; | |
321 | } | |
322 | ||
323 | static int mmapped_ref_iterator_peel(struct ref_iterator *ref_iterator, | |
324 | struct object_id *peeled) | |
325 | { | |
326 | struct mmapped_ref_iterator *iter = | |
327 | (struct mmapped_ref_iterator *)ref_iterator; | |
328 | ||
329 | if ((iter->base.flags & REF_KNOWS_PEELED)) { | |
330 | oidcpy(peeled, &iter->peeled); | |
331 | return is_null_oid(&iter->peeled) ? -1 : 0; | |
332 | } else if ((iter->base.flags & (REF_ISBROKEN | REF_ISSYMREF))) { | |
333 | return -1; | |
334 | } else { | |
335 | return !!peel_object(iter->oid.hash, peeled->hash); | |
336 | } | |
337 | } | |
338 | ||
339 | static int mmapped_ref_iterator_abort(struct ref_iterator *ref_iterator) | |
340 | { | |
341 | struct mmapped_ref_iterator *iter = | |
342 | (struct mmapped_ref_iterator *)ref_iterator; | |
343 | ||
344 | release_packed_ref_cache(iter->packed_refs); | |
345 | strbuf_release(&iter->refname_buf); | |
346 | base_ref_iterator_free(ref_iterator); | |
347 | return ITER_DONE; | |
348 | } | |
349 | ||
350 | static struct ref_iterator_vtable mmapped_ref_iterator_vtable = { | |
351 | mmapped_ref_iterator_advance, | |
352 | mmapped_ref_iterator_peel, | |
353 | mmapped_ref_iterator_abort | |
354 | }; | |
355 | ||
356 | struct ref_iterator *mmapped_ref_iterator_begin( | |
9cfb3dc0 MH |
357 | struct packed_ref_cache *packed_refs, |
358 | const char *pos, const char *eof) | |
359 | { | |
360 | struct mmapped_ref_iterator *iter = xcalloc(1, sizeof(*iter)); | |
361 | struct ref_iterator *ref_iterator = &iter->base; | |
362 | ||
5b633610 MH |
363 | if (!packed_refs->buf) |
364 | return empty_ref_iterator_begin(); | |
365 | ||
02b920f3 | 366 | base_ref_iterator_init(ref_iterator, &mmapped_ref_iterator_vtable, 1); |
9cfb3dc0 MH |
367 | |
368 | iter->packed_refs = packed_refs; | |
369 | acquire_packed_ref_cache(iter->packed_refs); | |
370 | iter->pos = pos; | |
371 | iter->eof = eof; | |
372 | strbuf_init(&iter->refname_buf, 0); | |
373 | ||
374 | iter->base.oid = &iter->oid; | |
375 | ||
376 | return ref_iterator; | |
377 | } | |
378 | ||
02b920f3 MH |
379 | struct packed_ref_entry { |
380 | const char *start; | |
381 | size_t len; | |
382 | }; | |
383 | ||
384 | static int cmp_packed_ref_entries(const void *v1, const void *v2) | |
385 | { | |
386 | const struct packed_ref_entry *e1 = v1, *e2 = v2; | |
387 | const char *r1 = e1->start + GIT_SHA1_HEXSZ + 1; | |
388 | const char *r2 = e2->start + GIT_SHA1_HEXSZ + 1; | |
389 | ||
390 | while (1) { | |
391 | if (*r1 == '\n') | |
392 | return *r2 == '\n' ? 0 : -1; | |
393 | if (*r1 != *r2) { | |
394 | if (*r2 == '\n') | |
395 | return 1; | |
396 | else | |
397 | return (unsigned char)*r1 < (unsigned char)*r2 ? -1 : +1; | |
398 | } | |
399 | r1++; | |
400 | r2++; | |
401 | } | |
402 | } | |
403 | ||
d1cf1551 MH |
404 | /* |
405 | * Compare a packed-refs record pointed to by `rec` to the specified | |
406 | * NUL-terminated refname. | |
407 | */ | |
408 | static int cmp_entry_to_refname(const char *rec, const char *refname) | |
409 | { | |
410 | const char *r1 = rec + GIT_SHA1_HEXSZ + 1; | |
411 | const char *r2 = refname; | |
412 | ||
413 | while (1) { | |
414 | if (*r1 == '\n') | |
415 | return *r2 ? -1 : 0; | |
416 | if (!*r2) | |
417 | return 1; | |
418 | if (*r1 != *r2) | |
419 | return (unsigned char)*r1 < (unsigned char)*r2 ? -1 : +1; | |
420 | r1++; | |
421 | r2++; | |
422 | } | |
423 | } | |
424 | ||
02b920f3 MH |
425 | /* |
426 | * `packed_refs->buf` is not known to be sorted. Check whether it is, | |
427 | * and if not, sort it into new memory and munmap/free the old | |
428 | * storage. | |
429 | */ | |
430 | static void sort_packed_refs(struct packed_ref_cache *packed_refs) | |
431 | { | |
432 | struct packed_ref_entry *entries = NULL; | |
433 | size_t alloc = 0, nr = 0; | |
434 | int sorted = 1; | |
435 | const char *pos, *eof, *eol; | |
436 | size_t len, i; | |
437 | char *new_buffer, *dst; | |
438 | ||
439 | pos = packed_refs->buf + packed_refs->header_len; | |
440 | eof = packed_refs->eof; | |
441 | len = eof - pos; | |
442 | ||
443 | if (!len) | |
444 | return; | |
445 | ||
446 | /* | |
447 | * Initialize entries based on a crude estimate of the number | |
448 | * of references in the file (we'll grow it below if needed): | |
449 | */ | |
450 | ALLOC_GROW(entries, len / 80 + 20, alloc); | |
451 | ||
452 | while (pos < eof) { | |
453 | eol = memchr(pos, '\n', eof - pos); | |
454 | if (!eol) | |
455 | /* The safety check should prevent this. */ | |
456 | BUG("unterminated line found in packed-refs"); | |
457 | if (eol - pos < GIT_SHA1_HEXSZ + 2) | |
458 | die_invalid_line(packed_refs->refs->path, | |
459 | pos, eof - pos); | |
460 | eol++; | |
461 | if (eol < eof && *eol == '^') { | |
462 | /* | |
463 | * Keep any peeled line together with its | |
464 | * reference: | |
465 | */ | |
466 | const char *peeled_start = eol; | |
467 | ||
468 | eol = memchr(peeled_start, '\n', eof - peeled_start); | |
469 | if (!eol) | |
470 | /* The safety check should prevent this. */ | |
471 | BUG("unterminated peeled line found in packed-refs"); | |
472 | eol++; | |
473 | } | |
474 | ||
475 | ALLOC_GROW(entries, nr + 1, alloc); | |
476 | entries[nr].start = pos; | |
477 | entries[nr].len = eol - pos; | |
478 | nr++; | |
479 | ||
480 | if (sorted && | |
481 | nr > 1 && | |
482 | cmp_packed_ref_entries(&entries[nr - 2], | |
483 | &entries[nr - 1]) >= 0) | |
484 | sorted = 0; | |
485 | ||
486 | pos = eol; | |
487 | } | |
488 | ||
489 | if (sorted) | |
490 | goto cleanup; | |
491 | ||
492 | /* We need to sort the memory. First we sort the entries array: */ | |
493 | QSORT(entries, nr, cmp_packed_ref_entries); | |
494 | ||
495 | /* | |
496 | * Allocate a new chunk of memory, and copy the old memory to | |
497 | * the new in the order indicated by `entries` (not bothering | |
498 | * with the header line): | |
499 | */ | |
500 | new_buffer = xmalloc(len); | |
501 | for (dst = new_buffer, i = 0; i < nr; i++) { | |
502 | memcpy(dst, entries[i].start, entries[i].len); | |
503 | dst += entries[i].len; | |
504 | } | |
505 | ||
506 | /* | |
507 | * Now munmap the old buffer and use the sorted buffer in its | |
508 | * place: | |
509 | */ | |
510 | release_packed_ref_buffer(packed_refs); | |
511 | packed_refs->buf = new_buffer; | |
512 | packed_refs->eof = new_buffer + len; | |
513 | packed_refs->header_len = 0; | |
514 | ||
515 | cleanup: | |
516 | free(entries); | |
517 | } | |
518 | ||
519 | /* | |
520 | * Return a pointer to the start of the record that contains the | |
521 | * character `*p` (which must be within the buffer). If no other | |
522 | * record start is found, return `buf`. | |
523 | */ | |
524 | static const char *find_start_of_record(const char *buf, const char *p) | |
525 | { | |
526 | while (p > buf && (p[-1] != '\n' || p[0] == '^')) | |
527 | p--; | |
528 | return p; | |
529 | } | |
530 | ||
d1cf1551 MH |
531 | /* |
532 | * Return a pointer to the start of the record following the record | |
533 | * that contains `*p`. If none is found before `end`, return `end`. | |
534 | */ | |
535 | static const char *find_end_of_record(const char *p, const char *end) | |
536 | { | |
537 | while (++p < end && (p[-1] != '\n' || p[0] == '^')) | |
538 | ; | |
539 | return p; | |
540 | } | |
541 | ||
02b920f3 MH |
542 | /* |
543 | * We want to be able to compare mmapped reference records quickly, | |
544 | * without totally parsing them. We can do so because the records are | |
545 | * LF-terminated, and the refname should start exactly (GIT_SHA1_HEXSZ | |
546 | * + 1) bytes past the beginning of the record. | |
547 | * | |
548 | * But what if the `packed-refs` file contains garbage? We're willing | |
549 | * to tolerate not detecting the problem, as long as we don't produce | |
550 | * totally garbled output (we can't afford to check the integrity of | |
551 | * the whole file during every Git invocation). But we do want to be | |
552 | * sure that we never read past the end of the buffer in memory and | |
553 | * perform an illegal memory access. | |
554 | * | |
555 | * Guarantee that minimum level of safety by verifying that the last | |
556 | * record in the file is LF-terminated, and that it has at least | |
557 | * (GIT_SHA1_HEXSZ + 1) characters before the LF. Die if either of | |
558 | * these checks fails. | |
559 | */ | |
560 | static void verify_buffer_safe(struct packed_ref_cache *packed_refs) | |
561 | { | |
562 | const char *buf = packed_refs->buf + packed_refs->header_len; | |
563 | const char *eof = packed_refs->eof; | |
564 | const char *last_line; | |
565 | ||
566 | if (buf == eof) | |
567 | return; | |
568 | ||
569 | last_line = find_start_of_record(buf, eof - 1); | |
570 | if (*(eof - 1) != '\n' || eof - last_line < GIT_SHA1_HEXSZ + 2) | |
571 | die_invalid_line(packed_refs->refs->path, | |
572 | last_line, eof - last_line); | |
573 | } | |
574 | ||
5b633610 MH |
575 | /* |
576 | * Depending on `mmap_strategy`, either mmap or read the contents of | |
577 | * the `packed-refs` file into the `packed_refs` instance. Return 1 if | |
578 | * the file existed and was read, or 0 if the file was absent. Die on | |
579 | * errors. | |
580 | */ | |
581 | static int load_contents(struct packed_ref_cache *packed_refs) | |
582 | { | |
583 | int fd; | |
584 | struct stat st; | |
585 | size_t size; | |
586 | ssize_t bytes_read; | |
587 | ||
588 | fd = open(packed_refs->refs->path, O_RDONLY); | |
589 | if (fd < 0) { | |
590 | if (errno == ENOENT) { | |
591 | /* | |
592 | * This is OK; it just means that no | |
593 | * "packed-refs" file has been written yet, | |
594 | * which is equivalent to it being empty, | |
595 | * which is its state when initialized with | |
596 | * zeros. | |
597 | */ | |
598 | return 0; | |
599 | } else { | |
600 | die_errno("couldn't read %s", packed_refs->refs->path); | |
601 | } | |
602 | } | |
603 | ||
604 | stat_validity_update(&packed_refs->validity, fd); | |
605 | ||
606 | if (fstat(fd, &st) < 0) | |
607 | die_errno("couldn't stat %s", packed_refs->refs->path); | |
608 | size = xsize_t(st.st_size); | |
609 | ||
610 | switch (mmap_strategy) { | |
611 | case MMAP_NONE: | |
5b633610 MH |
612 | packed_refs->buf = xmalloc(size); |
613 | bytes_read = read_in_full(fd, packed_refs->buf, size); | |
614 | if (bytes_read < 0 || bytes_read != size) | |
615 | die_errno("couldn't read %s", packed_refs->refs->path); | |
616 | packed_refs->eof = packed_refs->buf + size; | |
617 | packed_refs->mmapped = 0; | |
618 | break; | |
02b920f3 | 619 | case MMAP_TEMPORARY: |
5b633610 MH |
620 | case MMAP_OK: |
621 | packed_refs->buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); | |
622 | packed_refs->eof = packed_refs->buf + size; | |
623 | packed_refs->mmapped = 1; | |
624 | break; | |
625 | } | |
626 | close(fd); | |
627 | ||
628 | return 1; | |
629 | } | |
630 | ||
d1cf1551 MH |
631 | /* |
632 | * Find the place in `cache->buf` where the start of the record for | |
633 | * `refname` starts. If `mustexist` is true and the reference doesn't | |
634 | * exist, then return NULL. If `mustexist` is false and the reference | |
635 | * doesn't exist, then return the point where that reference would be | |
636 | * inserted. In the latter mode, `refname` doesn't have to be a proper | |
637 | * reference name; for example, one could search for "refs/replace/" | |
638 | * to find the start of any replace references. | |
639 | * | |
640 | * The record is sought using a binary search, so `cache->buf` must be | |
641 | * sorted. | |
642 | */ | |
643 | static const char *find_reference_location(struct packed_ref_cache *cache, | |
644 | const char *refname, int mustexist) | |
645 | { | |
646 | /* | |
647 | * This is not *quite* a garden-variety binary search, because | |
648 | * the data we're searching is made up of records, and we | |
649 | * always need to find the beginning of a record to do a | |
650 | * comparison. A "record" here is one line for the reference | |
651 | * itself and zero or one peel lines that start with '^'. Our | |
652 | * loop invariant is described in the next two comments. | |
653 | */ | |
654 | ||
655 | /* | |
656 | * A pointer to the character at the start of a record whose | |
657 | * preceding records all have reference names that come | |
658 | * *before* `refname`. | |
659 | */ | |
660 | const char *lo = cache->buf + cache->header_len; | |
661 | ||
662 | /* | |
663 | * A pointer to a the first character of a record whose | |
664 | * reference name comes *after* `refname`. | |
665 | */ | |
666 | const char *hi = cache->eof; | |
667 | ||
668 | while (lo < hi) { | |
669 | const char *mid, *rec; | |
670 | int cmp; | |
671 | ||
672 | mid = lo + (hi - lo) / 2; | |
673 | rec = find_start_of_record(lo, mid); | |
674 | cmp = cmp_entry_to_refname(rec, refname); | |
675 | if (cmp < 0) { | |
676 | lo = find_end_of_record(mid, hi); | |
677 | } else if (cmp > 0) { | |
678 | hi = rec; | |
679 | } else { | |
680 | return rec; | |
681 | } | |
682 | } | |
683 | ||
684 | if (mustexist) | |
685 | return NULL; | |
686 | else | |
687 | return lo; | |
688 | } | |
689 | ||
67be7c5a | 690 | /* |
f0a7dc86 | 691 | * Read from the `packed-refs` file into a newly-allocated |
67be7c5a MH |
692 | * `packed_ref_cache` and return it. The return value will already |
693 | * have its reference count incremented. | |
694 | * | |
695 | * A comment line of the form "# pack-refs with: " may contain zero or | |
696 | * more traits. We interpret the traits as follows: | |
697 | * | |
02b920f3 | 698 | * Neither `peeled` nor `fully-peeled`: |
67be7c5a MH |
699 | * |
700 | * Probably no references are peeled. But if the file contains a | |
701 | * peeled value for a reference, we will use it. | |
702 | * | |
02b920f3 | 703 | * `peeled`: |
67be7c5a MH |
704 | * |
705 | * References under "refs/tags/", if they *can* be peeled, *are* | |
706 | * peeled in this file. References outside of "refs/tags/" are | |
707 | * probably not peeled even if they could have been, but if we find | |
708 | * a peeled value for such a reference we will use it. | |
709 | * | |
02b920f3 | 710 | * `fully-peeled`: |
67be7c5a MH |
711 | * |
712 | * All references in the file that can be peeled are peeled. | |
713 | * Inversely (and this is more important), any references in the | |
714 | * file for which no peeled value is recorded is not peelable. This | |
715 | * trait should typically be written alongside "peeled" for | |
716 | * compatibility with older clients, but we do not require it | |
717 | * (i.e., "peeled" is a no-op if "fully-peeled" is set). | |
02b920f3 MH |
718 | * |
719 | * `sorted`: | |
720 | * | |
721 | * The references in this file are known to be sorted by refname. | |
67be7c5a | 722 | */ |
f0a7dc86 | 723 | static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs) |
67be7c5a | 724 | { |
67be7c5a | 725 | struct packed_ref_cache *packed_refs = xcalloc(1, sizeof(*packed_refs)); |
02b920f3 | 726 | int sorted = 0; |
67be7c5a | 727 | |
f0a7dc86 | 728 | packed_refs->refs = refs; |
67be7c5a | 729 | acquire_packed_ref_cache(packed_refs); |
daa45408 | 730 | packed_refs->peeled = PEELED_NONE; |
67be7c5a | 731 | |
5b633610 MH |
732 | if (!load_contents(packed_refs)) |
733 | return packed_refs; | |
67be7c5a | 734 | |
36f23534 | 735 | /* If the file has a header line, process it: */ |
5b633610 | 736 | if (packed_refs->buf < packed_refs->eof && *packed_refs->buf == '#') { |
9cfb3dc0 | 737 | struct strbuf tmp = STRBUF_INIT; |
a8811695 | 738 | char *p; |
9cfb3dc0 | 739 | const char *eol; |
a8811695 | 740 | struct string_list traits = STRING_LIST_INIT_NODUP; |
36f23534 | 741 | |
5b633610 MH |
742 | eol = memchr(packed_refs->buf, '\n', |
743 | packed_refs->eof - packed_refs->buf); | |
36f23534 | 744 | if (!eol) |
5b633610 MH |
745 | die_unterminated_line(refs->path, |
746 | packed_refs->buf, | |
747 | packed_refs->eof - packed_refs->buf); | |
36f23534 | 748 | |
5b633610 | 749 | strbuf_add(&tmp, packed_refs->buf, eol - packed_refs->buf); |
36f23534 | 750 | |
6a9bc403 | 751 | if (!skip_prefix(tmp.buf, "# pack-refs with:", (const char **)&p)) |
5b633610 MH |
752 | die_invalid_line(refs->path, |
753 | packed_refs->buf, | |
754 | packed_refs->eof - packed_refs->buf); | |
36f23534 | 755 | |
a8811695 MH |
756 | string_list_split_in_place(&traits, p, ' ', -1); |
757 | ||
758 | if (unsorted_string_list_has_string(&traits, "fully-peeled")) | |
daa45408 | 759 | packed_refs->peeled = PEELED_FULLY; |
a8811695 | 760 | else if (unsorted_string_list_has_string(&traits, "peeled")) |
daa45408 | 761 | packed_refs->peeled = PEELED_TAGS; |
02b920f3 MH |
762 | |
763 | sorted = unsorted_string_list_has_string(&traits, "sorted"); | |
764 | ||
36f23534 MH |
765 | /* perhaps other traits later as well */ |
766 | ||
767 | /* The "+ 1" is for the LF character. */ | |
5b633610 | 768 | packed_refs->header_len = eol + 1 - packed_refs->buf; |
a8811695 MH |
769 | |
770 | string_list_clear(&traits, 0); | |
9cfb3dc0 | 771 | strbuf_release(&tmp); |
36f23534 MH |
772 | } |
773 | ||
02b920f3 MH |
774 | verify_buffer_safe(packed_refs); |
775 | ||
776 | if (!sorted) { | |
777 | sort_packed_refs(packed_refs); | |
778 | ||
779 | /* | |
780 | * Reordering the records might have moved a short one | |
781 | * to the end of the buffer, so verify the buffer's | |
782 | * safety again: | |
783 | */ | |
784 | verify_buffer_safe(packed_refs); | |
785 | } | |
786 | ||
787 | if (mmap_strategy != MMAP_OK && packed_refs->mmapped) { | |
788 | /* | |
789 | * We don't want to leave the file mmapped, so we are | |
790 | * forced to make a copy now: | |
791 | */ | |
792 | size_t size = packed_refs->eof - | |
793 | (packed_refs->buf + packed_refs->header_len); | |
794 | char *buf_copy = xmalloc(size); | |
795 | ||
796 | memcpy(buf_copy, packed_refs->buf + packed_refs->header_len, size); | |
797 | release_packed_ref_buffer(packed_refs); | |
798 | packed_refs->buf = buf_copy; | |
799 | packed_refs->eof = buf_copy + size; | |
800 | } | |
801 | ||
67be7c5a MH |
802 | return packed_refs; |
803 | } | |
804 | ||
805 | /* | |
806 | * Check that the packed refs cache (if any) still reflects the | |
807 | * contents of the file. If not, clear the cache. | |
808 | */ | |
809 | static void validate_packed_ref_cache(struct packed_ref_store *refs) | |
810 | { | |
811 | if (refs->cache && | |
812 | !stat_validity_check(&refs->cache->validity, refs->path)) | |
813 | clear_packed_ref_cache(refs); | |
814 | } | |
815 | ||
816 | /* | |
817 | * Get the packed_ref_cache for the specified packed_ref_store, | |
818 | * creating and populating it if it hasn't been read before or if the | |
819 | * file has been changed (according to its `validity` field) since it | |
820 | * was last read. On the other hand, if we hold the lock, then assume | |
821 | * that the file hasn't been changed out from under us, so skip the | |
822 | * extra `stat()` call in `stat_validity_check()`. | |
823 | */ | |
824 | static struct packed_ref_cache *get_packed_ref_cache(struct packed_ref_store *refs) | |
825 | { | |
826 | if (!is_lock_file_locked(&refs->lock)) | |
827 | validate_packed_ref_cache(refs); | |
828 | ||
829 | if (!refs->cache) | |
f0a7dc86 | 830 | refs->cache = read_packed_refs(refs); |
67be7c5a MH |
831 | |
832 | return refs->cache; | |
833 | } | |
834 | ||
e0cc8ac8 MH |
835 | static int packed_read_raw_ref(struct ref_store *ref_store, |
836 | const char *refname, unsigned char *sha1, | |
837 | struct strbuf *referent, unsigned int *type) | |
67be7c5a | 838 | { |
e0cc8ac8 MH |
839 | struct packed_ref_store *refs = |
840 | packed_downcast(ref_store, REF_STORE_READ, "read_raw_ref"); | |
f3987ab3 MH |
841 | struct packed_ref_cache *packed_refs = get_packed_ref_cache(refs); |
842 | const char *rec; | |
67be7c5a MH |
843 | |
844 | *type = 0; | |
845 | ||
f3987ab3 MH |
846 | rec = find_reference_location(packed_refs, refname, 1); |
847 | ||
848 | if (!rec) { | |
849 | /* refname is not a packed reference. */ | |
67be7c5a MH |
850 | errno = ENOENT; |
851 | return -1; | |
852 | } | |
853 | ||
f3987ab3 MH |
854 | if (get_sha1_hex(rec, sha1)) |
855 | die_invalid_line(refs->path, rec, packed_refs->eof - rec); | |
856 | ||
67be7c5a MH |
857 | *type = REF_ISPACKED; |
858 | return 0; | |
859 | } | |
860 | ||
67be7c5a MH |
861 | struct packed_ref_iterator { |
862 | struct ref_iterator base; | |
863 | ||
864 | struct packed_ref_cache *cache; | |
865 | struct ref_iterator *iter0; | |
866 | unsigned int flags; | |
867 | }; | |
868 | ||
869 | static int packed_ref_iterator_advance(struct ref_iterator *ref_iterator) | |
870 | { | |
871 | struct packed_ref_iterator *iter = | |
872 | (struct packed_ref_iterator *)ref_iterator; | |
873 | int ok; | |
874 | ||
875 | while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) { | |
876 | if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY && | |
877 | ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE) | |
878 | continue; | |
879 | ||
880 | if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) && | |
881 | !ref_resolves_to_object(iter->iter0->refname, | |
882 | iter->iter0->oid, | |
883 | iter->iter0->flags)) | |
884 | continue; | |
885 | ||
886 | iter->base.refname = iter->iter0->refname; | |
887 | iter->base.oid = iter->iter0->oid; | |
888 | iter->base.flags = iter->iter0->flags; | |
889 | return ITER_OK; | |
890 | } | |
891 | ||
892 | iter->iter0 = NULL; | |
893 | if (ref_iterator_abort(ref_iterator) != ITER_DONE) | |
894 | ok = ITER_ERROR; | |
895 | ||
896 | return ok; | |
897 | } | |
898 | ||
899 | static int packed_ref_iterator_peel(struct ref_iterator *ref_iterator, | |
900 | struct object_id *peeled) | |
901 | { | |
902 | struct packed_ref_iterator *iter = | |
903 | (struct packed_ref_iterator *)ref_iterator; | |
904 | ||
905 | return ref_iterator_peel(iter->iter0, peeled); | |
906 | } | |
907 | ||
908 | static int packed_ref_iterator_abort(struct ref_iterator *ref_iterator) | |
909 | { | |
910 | struct packed_ref_iterator *iter = | |
911 | (struct packed_ref_iterator *)ref_iterator; | |
912 | int ok = ITER_DONE; | |
913 | ||
914 | if (iter->iter0) | |
915 | ok = ref_iterator_abort(iter->iter0); | |
916 | ||
917 | release_packed_ref_cache(iter->cache); | |
918 | base_ref_iterator_free(ref_iterator); | |
919 | return ok; | |
920 | } | |
921 | ||
922 | static struct ref_iterator_vtable packed_ref_iterator_vtable = { | |
923 | packed_ref_iterator_advance, | |
924 | packed_ref_iterator_peel, | |
925 | packed_ref_iterator_abort | |
926 | }; | |
927 | ||
e0cc8ac8 MH |
928 | static struct ref_iterator *packed_ref_iterator_begin( |
929 | struct ref_store *ref_store, | |
67be7c5a MH |
930 | const char *prefix, unsigned int flags) |
931 | { | |
e0cc8ac8 | 932 | struct packed_ref_store *refs; |
d1cf1551 MH |
933 | struct packed_ref_cache *packed_refs; |
934 | const char *start; | |
67be7c5a MH |
935 | struct packed_ref_iterator *iter; |
936 | struct ref_iterator *ref_iterator; | |
e0cc8ac8 MH |
937 | unsigned int required_flags = REF_STORE_READ; |
938 | ||
939 | if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) | |
940 | required_flags |= REF_STORE_ODB; | |
941 | refs = packed_downcast(ref_store, required_flags, "ref_iterator_begin"); | |
67be7c5a MH |
942 | |
943 | iter = xcalloc(1, sizeof(*iter)); | |
944 | ref_iterator = &iter->base; | |
8738a8a4 | 945 | base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable, 1); |
67be7c5a MH |
946 | |
947 | /* | |
948 | * Note that get_packed_ref_cache() internally checks whether | |
949 | * the packed-ref cache is up to date with what is on disk, | |
950 | * and re-reads it if not. | |
951 | */ | |
d1cf1551 MH |
952 | iter->cache = packed_refs = get_packed_ref_cache(refs); |
953 | acquire_packed_ref_cache(packed_refs); | |
67be7c5a | 954 | |
d1cf1551 MH |
955 | if (prefix && *prefix) |
956 | start = find_reference_location(packed_refs, prefix, 0); | |
957 | else | |
958 | start = packed_refs->buf + packed_refs->header_len; | |
959 | ||
9dd389f3 MH |
960 | iter->iter0 = mmapped_ref_iterator_begin(packed_refs, |
961 | start, packed_refs->eof); | |
67be7c5a MH |
962 | |
963 | iter->flags = flags; | |
964 | ||
d1cf1551 MH |
965 | if (prefix && *prefix) |
966 | /* Stop iteration after we've gone *past* prefix: */ | |
967 | ref_iterator = prefix_ref_iterator_begin(ref_iterator, prefix, 0); | |
968 | ||
67be7c5a MH |
969 | return ref_iterator; |
970 | } | |
971 | ||
972 | /* | |
973 | * Write an entry to the packed-refs file for the specified refname. | |
3478983b MH |
974 | * If peeled is non-NULL, write it as the entry's peeled value. On |
975 | * error, return a nonzero value and leave errno set at the value left | |
976 | * by the failing call to `fprintf()`. | |
67be7c5a | 977 | */ |
3478983b MH |
978 | static int write_packed_entry(FILE *fh, const char *refname, |
979 | const unsigned char *sha1, | |
980 | const unsigned char *peeled) | |
67be7c5a | 981 | { |
3478983b MH |
982 | if (fprintf(fh, "%s %s\n", sha1_to_hex(sha1), refname) < 0 || |
983 | (peeled && fprintf(fh, "^%s\n", sha1_to_hex(peeled)) < 0)) | |
984 | return -1; | |
985 | ||
986 | return 0; | |
67be7c5a MH |
987 | } |
988 | ||
c8bed835 | 989 | int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err) |
67be7c5a | 990 | { |
e0cc8ac8 MH |
991 | struct packed_ref_store *refs = |
992 | packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN, | |
b7de57d8 | 993 | "packed_refs_lock"); |
67be7c5a MH |
994 | static int timeout_configured = 0; |
995 | static int timeout_value = 1000; | |
67be7c5a | 996 | |
67be7c5a MH |
997 | if (!timeout_configured) { |
998 | git_config_get_int("core.packedrefstimeout", &timeout_value); | |
999 | timeout_configured = 1; | |
1000 | } | |
1001 | ||
42dfa7ec MH |
1002 | /* |
1003 | * Note that we close the lockfile immediately because we | |
1004 | * don't write new content to it, but rather to a separate | |
1005 | * tempfile. | |
1006 | */ | |
67be7c5a MH |
1007 | if (hold_lock_file_for_update_timeout( |
1008 | &refs->lock, | |
1009 | refs->path, | |
c8bed835 MH |
1010 | flags, timeout_value) < 0) { |
1011 | unable_to_lock_message(refs->path, errno, err); | |
1012 | return -1; | |
1013 | } | |
1014 | ||
1015 | if (close_lock_file(&refs->lock)) { | |
1016 | strbuf_addf(err, "unable to close %s: %s", refs->path, strerror(errno)); | |
67be7c5a | 1017 | return -1; |
c8bed835 | 1018 | } |
67be7c5a MH |
1019 | |
1020 | /* | |
1021 | * Now that we hold the `packed-refs` lock, make sure that our | |
1022 | * cache matches the current version of the file. Normally | |
1023 | * `get_packed_ref_cache()` does that for us, but that | |
1024 | * function assumes that when the file is locked, any existing | |
1025 | * cache is still valid. We've just locked the file, but it | |
1026 | * might have changed the moment *before* we locked it. | |
1027 | */ | |
1028 | validate_packed_ref_cache(refs); | |
1029 | ||
39c8df0c MH |
1030 | /* |
1031 | * Now make sure that the packed-refs file as it exists in the | |
1032 | * locked state is loaded into the cache: | |
1033 | */ | |
1034 | get_packed_ref_cache(refs); | |
67be7c5a MH |
1035 | return 0; |
1036 | } | |
1037 | ||
49aebcf4 MH |
1038 | void packed_refs_unlock(struct ref_store *ref_store) |
1039 | { | |
1040 | struct packed_ref_store *refs = packed_downcast( | |
1041 | ref_store, | |
1042 | REF_STORE_READ | REF_STORE_WRITE, | |
1043 | "packed_refs_unlock"); | |
1044 | ||
1045 | if (!is_lock_file_locked(&refs->lock)) | |
1046 | die("BUG: packed_refs_unlock() called when not locked"); | |
1047 | rollback_lock_file(&refs->lock); | |
49aebcf4 MH |
1048 | } |
1049 | ||
1050 | int packed_refs_is_locked(struct ref_store *ref_store) | |
1051 | { | |
1052 | struct packed_ref_store *refs = packed_downcast( | |
1053 | ref_store, | |
1054 | REF_STORE_READ | REF_STORE_WRITE, | |
1055 | "packed_refs_is_locked"); | |
1056 | ||
1057 | return is_lock_file_locked(&refs->lock); | |
1058 | } | |
1059 | ||
67be7c5a MH |
1060 | /* |
1061 | * The packed-refs header line that we write out. Perhaps other | |
a8811695 MH |
1062 | * traits will be added later. |
1063 | * | |
1064 | * Note that earlier versions of Git used to parse these traits by | |
1065 | * looking for " trait " in the line. For this reason, the space after | |
1066 | * the colon and the trailing space are required. | |
67be7c5a MH |
1067 | */ |
1068 | static const char PACKED_REFS_HEADER[] = | |
02b920f3 | 1069 | "# pack-refs with: peeled fully-peeled sorted \n"; |
67be7c5a | 1070 | |
e0cc8ac8 MH |
1071 | static int packed_init_db(struct ref_store *ref_store, struct strbuf *err) |
1072 | { | |
1073 | /* Nothing to do. */ | |
1074 | return 0; | |
1075 | } | |
1076 | ||
2775d872 MH |
1077 | /* |
1078 | * Write the packed-refs from the cache to the packed-refs tempfile, | |
1079 | * incorporating any changes from `updates`. `updates` must be a | |
1080 | * sorted string list whose keys are the refnames and whose util | |
1081 | * values are `struct ref_update *`. On error, rollback the tempfile, | |
1082 | * write an error message to `err`, and return a nonzero value. | |
1083 | * | |
1084 | * The packfile must be locked before calling this function and will | |
1085 | * remain locked when it is done. | |
1086 | */ | |
1087 | static int write_with_updates(struct packed_ref_store *refs, | |
1088 | struct string_list *updates, | |
1089 | struct strbuf *err) | |
1090 | { | |
1091 | struct ref_iterator *iter = NULL; | |
1092 | size_t i; | |
1093 | int ok; | |
1094 | FILE *out; | |
1095 | struct strbuf sb = STRBUF_INIT; | |
1096 | char *packed_refs_path; | |
1097 | ||
1098 | if (!is_lock_file_locked(&refs->lock)) | |
1099 | die("BUG: write_with_updates() called while unlocked"); | |
1100 | ||
1101 | /* | |
1102 | * If packed-refs is a symlink, we want to overwrite the | |
1103 | * symlinked-to file, not the symlink itself. Also, put the | |
1104 | * staging file next to it: | |
1105 | */ | |
1106 | packed_refs_path = get_locked_file_path(&refs->lock); | |
1107 | strbuf_addf(&sb, "%s.new", packed_refs_path); | |
1108 | free(packed_refs_path); | |
1109 | if (create_tempfile(&refs->tempfile, sb.buf) < 0) { | |
1110 | strbuf_addf(err, "unable to create file %s: %s", | |
1111 | sb.buf, strerror(errno)); | |
1112 | strbuf_release(&sb); | |
1113 | return -1; | |
1114 | } | |
1115 | strbuf_release(&sb); | |
1116 | ||
1117 | out = fdopen_tempfile(&refs->tempfile, "w"); | |
1118 | if (!out) { | |
1119 | strbuf_addf(err, "unable to fdopen packed-refs tempfile: %s", | |
1120 | strerror(errno)); | |
1121 | goto error; | |
1122 | } | |
1123 | ||
1124 | if (fprintf(out, "%s", PACKED_REFS_HEADER) < 0) | |
1125 | goto write_error; | |
1126 | ||
1127 | /* | |
1128 | * We iterate in parallel through the current list of refs and | |
1129 | * the list of updates, processing an entry from at least one | |
1130 | * of the lists each time through the loop. When the current | |
1131 | * list of refs is exhausted, set iter to NULL. When the list | |
1132 | * of updates is exhausted, leave i set to updates->nr. | |
1133 | */ | |
1134 | iter = packed_ref_iterator_begin(&refs->base, "", | |
1135 | DO_FOR_EACH_INCLUDE_BROKEN); | |
1136 | if ((ok = ref_iterator_advance(iter)) != ITER_OK) | |
1137 | iter = NULL; | |
1138 | ||
1139 | i = 0; | |
1140 | ||
1141 | while (iter || i < updates->nr) { | |
1142 | struct ref_update *update = NULL; | |
1143 | int cmp; | |
1144 | ||
1145 | if (i >= updates->nr) { | |
1146 | cmp = -1; | |
1147 | } else { | |
1148 | update = updates->items[i].util; | |
1149 | ||
1150 | if (!iter) | |
1151 | cmp = +1; | |
1152 | else | |
1153 | cmp = strcmp(iter->refname, update->refname); | |
1154 | } | |
1155 | ||
1156 | if (!cmp) { | |
1157 | /* | |
1158 | * There is both an old value and an update | |
1159 | * for this reference. Check the old value if | |
1160 | * necessary: | |
1161 | */ | |
1162 | if ((update->flags & REF_HAVE_OLD)) { | |
1163 | if (is_null_oid(&update->old_oid)) { | |
1164 | strbuf_addf(err, "cannot update ref '%s': " | |
1165 | "reference already exists", | |
1166 | update->refname); | |
1167 | goto error; | |
1168 | } else if (oidcmp(&update->old_oid, iter->oid)) { | |
1169 | strbuf_addf(err, "cannot update ref '%s': " | |
1170 | "is at %s but expected %s", | |
1171 | update->refname, | |
1172 | oid_to_hex(iter->oid), | |
1173 | oid_to_hex(&update->old_oid)); | |
1174 | goto error; | |
1175 | } | |
1176 | } | |
1177 | ||
1178 | /* Now figure out what to use for the new value: */ | |
1179 | if ((update->flags & REF_HAVE_NEW)) { | |
1180 | /* | |
1181 | * The update takes precedence. Skip | |
1182 | * the iterator over the unneeded | |
1183 | * value. | |
1184 | */ | |
1185 | if ((ok = ref_iterator_advance(iter)) != ITER_OK) | |
1186 | iter = NULL; | |
1187 | cmp = +1; | |
1188 | } else { | |
1189 | /* | |
1190 | * The update doesn't actually want to | |
1191 | * change anything. We're done with it. | |
1192 | */ | |
1193 | i++; | |
1194 | cmp = -1; | |
1195 | } | |
1196 | } else if (cmp > 0) { | |
1197 | /* | |
1198 | * There is no old value but there is an | |
1199 | * update for this reference. Make sure that | |
1200 | * the update didn't expect an existing value: | |
1201 | */ | |
1202 | if ((update->flags & REF_HAVE_OLD) && | |
1203 | !is_null_oid(&update->old_oid)) { | |
1204 | strbuf_addf(err, "cannot update ref '%s': " | |
1205 | "reference is missing but expected %s", | |
1206 | update->refname, | |
1207 | oid_to_hex(&update->old_oid)); | |
1208 | goto error; | |
1209 | } | |
1210 | } | |
1211 | ||
1212 | if (cmp < 0) { | |
1213 | /* Pass the old reference through. */ | |
1214 | ||
1215 | struct object_id peeled; | |
1216 | int peel_error = ref_iterator_peel(iter, &peeled); | |
1217 | ||
1218 | if (write_packed_entry(out, iter->refname, | |
1219 | iter->oid->hash, | |
1220 | peel_error ? NULL : peeled.hash)) | |
1221 | goto write_error; | |
1222 | ||
1223 | if ((ok = ref_iterator_advance(iter)) != ITER_OK) | |
1224 | iter = NULL; | |
1225 | } else if (is_null_oid(&update->new_oid)) { | |
1226 | /* | |
1227 | * The update wants to delete the reference, | |
1228 | * and the reference either didn't exist or we | |
1229 | * have already skipped it. So we're done with | |
1230 | * the update (and don't have to write | |
1231 | * anything). | |
1232 | */ | |
1233 | i++; | |
1234 | } else { | |
1235 | struct object_id peeled; | |
1236 | int peel_error = peel_object(update->new_oid.hash, | |
1237 | peeled.hash); | |
1238 | ||
1239 | if (write_packed_entry(out, update->refname, | |
1240 | update->new_oid.hash, | |
1241 | peel_error ? NULL : peeled.hash)) | |
1242 | goto write_error; | |
1243 | ||
1244 | i++; | |
1245 | } | |
1246 | } | |
1247 | ||
1248 | if (ok != ITER_DONE) { | |
1249 | strbuf_addf(err, "unable to write packed-refs file: " | |
1250 | "error iterating over old contents"); | |
1251 | goto error; | |
1252 | } | |
1253 | ||
1254 | if (close_tempfile(&refs->tempfile)) { | |
1255 | strbuf_addf(err, "error closing file %s: %s", | |
1256 | get_tempfile_path(&refs->tempfile), | |
1257 | strerror(errno)); | |
1258 | strbuf_release(&sb); | |
1259 | return -1; | |
1260 | } | |
1261 | ||
1262 | return 0; | |
1263 | ||
1264 | write_error: | |
1265 | strbuf_addf(err, "error writing to %s: %s", | |
1266 | get_tempfile_path(&refs->tempfile), strerror(errno)); | |
1267 | ||
1268 | error: | |
1269 | if (iter) | |
1270 | ref_iterator_abort(iter); | |
1271 | ||
1272 | delete_tempfile(&refs->tempfile); | |
1273 | return -1; | |
1274 | } | |
1275 | ||
1276 | struct packed_transaction_backend_data { | |
1277 | /* True iff the transaction owns the packed-refs lock. */ | |
1278 | int own_lock; | |
1279 | ||
1280 | struct string_list updates; | |
1281 | }; | |
1282 | ||
1283 | static void packed_transaction_cleanup(struct packed_ref_store *refs, | |
1284 | struct ref_transaction *transaction) | |
1285 | { | |
1286 | struct packed_transaction_backend_data *data = transaction->backend_data; | |
1287 | ||
1288 | if (data) { | |
1289 | string_list_clear(&data->updates, 0); | |
1290 | ||
1291 | if (is_tempfile_active(&refs->tempfile)) | |
1292 | delete_tempfile(&refs->tempfile); | |
1293 | ||
1294 | if (data->own_lock && is_lock_file_locked(&refs->lock)) { | |
1295 | packed_refs_unlock(&refs->base); | |
1296 | data->own_lock = 0; | |
1297 | } | |
1298 | ||
1299 | free(data); | |
1300 | transaction->backend_data = NULL; | |
1301 | } | |
1302 | ||
1303 | transaction->state = REF_TRANSACTION_CLOSED; | |
1304 | } | |
1305 | ||
e0cc8ac8 MH |
1306 | static int packed_transaction_prepare(struct ref_store *ref_store, |
1307 | struct ref_transaction *transaction, | |
1308 | struct strbuf *err) | |
1309 | { | |
2775d872 MH |
1310 | struct packed_ref_store *refs = packed_downcast( |
1311 | ref_store, | |
1312 | REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB, | |
1313 | "ref_transaction_prepare"); | |
1314 | struct packed_transaction_backend_data *data; | |
1315 | size_t i; | |
1316 | int ret = TRANSACTION_GENERIC_ERROR; | |
1317 | ||
1318 | /* | |
1319 | * Note that we *don't* skip transactions with zero updates, | |
1320 | * because such a transaction might be executed for the side | |
1321 | * effect of ensuring that all of the references are peeled. | |
1322 | * If the caller wants to optimize away empty transactions, it | |
1323 | * should do so itself. | |
1324 | */ | |
1325 | ||
1326 | data = xcalloc(1, sizeof(*data)); | |
1327 | string_list_init(&data->updates, 0); | |
1328 | ||
1329 | transaction->backend_data = data; | |
1330 | ||
1331 | /* | |
1332 | * Stick the updates in a string list by refname so that we | |
1333 | * can sort them: | |
1334 | */ | |
1335 | for (i = 0; i < transaction->nr; i++) { | |
1336 | struct ref_update *update = transaction->updates[i]; | |
1337 | struct string_list_item *item = | |
1338 | string_list_append(&data->updates, update->refname); | |
1339 | ||
1340 | /* Store a pointer to update in item->util: */ | |
1341 | item->util = update; | |
1342 | } | |
1343 | string_list_sort(&data->updates); | |
1344 | ||
1345 | if (ref_update_reject_duplicates(&data->updates, err)) | |
1346 | goto failure; | |
1347 | ||
1348 | if (!is_lock_file_locked(&refs->lock)) { | |
1349 | if (packed_refs_lock(ref_store, 0, err)) | |
1350 | goto failure; | |
1351 | data->own_lock = 1; | |
1352 | } | |
1353 | ||
1354 | if (write_with_updates(refs, &data->updates, err)) | |
1355 | goto failure; | |
1356 | ||
1357 | transaction->state = REF_TRANSACTION_PREPARED; | |
1358 | return 0; | |
1359 | ||
1360 | failure: | |
1361 | packed_transaction_cleanup(refs, transaction); | |
1362 | return ret; | |
e0cc8ac8 MH |
1363 | } |
1364 | ||
1365 | static int packed_transaction_abort(struct ref_store *ref_store, | |
1366 | struct ref_transaction *transaction, | |
1367 | struct strbuf *err) | |
1368 | { | |
2775d872 MH |
1369 | struct packed_ref_store *refs = packed_downcast( |
1370 | ref_store, | |
1371 | REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB, | |
1372 | "ref_transaction_abort"); | |
1373 | ||
1374 | packed_transaction_cleanup(refs, transaction); | |
1375 | return 0; | |
e0cc8ac8 MH |
1376 | } |
1377 | ||
1378 | static int packed_transaction_finish(struct ref_store *ref_store, | |
1379 | struct ref_transaction *transaction, | |
1380 | struct strbuf *err) | |
1381 | { | |
2775d872 MH |
1382 | struct packed_ref_store *refs = packed_downcast( |
1383 | ref_store, | |
1384 | REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB, | |
1385 | "ref_transaction_finish"); | |
1386 | int ret = TRANSACTION_GENERIC_ERROR; | |
1387 | char *packed_refs_path; | |
1388 | ||
5b633610 MH |
1389 | clear_packed_ref_cache(refs); |
1390 | ||
2775d872 MH |
1391 | packed_refs_path = get_locked_file_path(&refs->lock); |
1392 | if (rename_tempfile(&refs->tempfile, packed_refs_path)) { | |
1393 | strbuf_addf(err, "error replacing %s: %s", | |
1394 | refs->path, strerror(errno)); | |
1395 | goto cleanup; | |
1396 | } | |
1397 | ||
2775d872 MH |
1398 | ret = 0; |
1399 | ||
1400 | cleanup: | |
1401 | free(packed_refs_path); | |
1402 | packed_transaction_cleanup(refs, transaction); | |
1403 | return ret; | |
e0cc8ac8 MH |
1404 | } |
1405 | ||
1406 | static int packed_initial_transaction_commit(struct ref_store *ref_store, | |
1407 | struct ref_transaction *transaction, | |
1408 | struct strbuf *err) | |
1409 | { | |
1410 | return ref_transaction_commit(transaction, err); | |
1411 | } | |
1412 | ||
1413 | static int packed_delete_refs(struct ref_store *ref_store, const char *msg, | |
1414 | struct string_list *refnames, unsigned int flags) | |
1415 | { | |
2fb330ca MH |
1416 | struct packed_ref_store *refs = |
1417 | packed_downcast(ref_store, REF_STORE_WRITE, "delete_refs"); | |
1418 | struct strbuf err = STRBUF_INIT; | |
1419 | struct ref_transaction *transaction; | |
1420 | struct string_list_item *item; | |
1421 | int ret; | |
1422 | ||
1423 | (void)refs; /* We need the check above, but don't use the variable */ | |
1424 | ||
1425 | if (!refnames->nr) | |
1426 | return 0; | |
1427 | ||
1428 | /* | |
1429 | * Since we don't check the references' old_oids, the | |
1430 | * individual updates can't fail, so we can pack all of the | |
1431 | * updates into a single transaction. | |
1432 | */ | |
1433 | ||
1434 | transaction = ref_store_transaction_begin(ref_store, &err); | |
1435 | if (!transaction) | |
1436 | return -1; | |
1437 | ||
1438 | for_each_string_list_item(item, refnames) { | |
1439 | if (ref_transaction_delete(transaction, item->string, NULL, | |
1440 | flags, msg, &err)) { | |
1441 | warning(_("could not delete reference %s: %s"), | |
1442 | item->string, err.buf); | |
1443 | strbuf_reset(&err); | |
1444 | } | |
1445 | } | |
1446 | ||
1447 | ret = ref_transaction_commit(transaction, &err); | |
1448 | ||
1449 | if (ret) { | |
1450 | if (refnames->nr == 1) | |
1451 | error(_("could not delete reference %s: %s"), | |
1452 | refnames->items[0].string, err.buf); | |
1453 | else | |
1454 | error(_("could not delete references: %s"), err.buf); | |
1455 | } | |
1456 | ||
1457 | ref_transaction_free(transaction); | |
1458 | strbuf_release(&err); | |
1459 | return ret; | |
e0cc8ac8 MH |
1460 | } |
1461 | ||
1462 | static int packed_pack_refs(struct ref_store *ref_store, unsigned int flags) | |
1463 | { | |
1464 | /* | |
1465 | * Packed refs are already packed. It might be that loose refs | |
1466 | * are packed *into* a packed refs store, but that is done by | |
1467 | * updating the packed references via a transaction. | |
1468 | */ | |
1469 | return 0; | |
1470 | } | |
1471 | ||
1472 | static int packed_create_symref(struct ref_store *ref_store, | |
1473 | const char *refname, const char *target, | |
1474 | const char *logmsg) | |
1475 | { | |
1476 | die("BUG: packed reference store does not support symrefs"); | |
1477 | } | |
1478 | ||
1479 | static int packed_rename_ref(struct ref_store *ref_store, | |
1480 | const char *oldrefname, const char *newrefname, | |
1481 | const char *logmsg) | |
1482 | { | |
1483 | die("BUG: packed reference store does not support renaming references"); | |
1484 | } | |
1485 | ||
1486 | static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store) | |
1487 | { | |
1488 | return empty_ref_iterator_begin(); | |
1489 | } | |
1490 | ||
1491 | static int packed_for_each_reflog_ent(struct ref_store *ref_store, | |
1492 | const char *refname, | |
1493 | each_reflog_ent_fn fn, void *cb_data) | |
1494 | { | |
1495 | return 0; | |
1496 | } | |
1497 | ||
1498 | static int packed_for_each_reflog_ent_reverse(struct ref_store *ref_store, | |
1499 | const char *refname, | |
1500 | each_reflog_ent_fn fn, | |
1501 | void *cb_data) | |
1502 | { | |
1503 | return 0; | |
1504 | } | |
1505 | ||
1506 | static int packed_reflog_exists(struct ref_store *ref_store, | |
1507 | const char *refname) | |
1508 | { | |
1509 | return 0; | |
1510 | } | |
1511 | ||
1512 | static int packed_create_reflog(struct ref_store *ref_store, | |
1513 | const char *refname, int force_create, | |
1514 | struct strbuf *err) | |
1515 | { | |
1516 | die("BUG: packed reference store does not support reflogs"); | |
1517 | } | |
1518 | ||
1519 | static int packed_delete_reflog(struct ref_store *ref_store, | |
1520 | const char *refname) | |
1521 | { | |
1522 | return 0; | |
1523 | } | |
1524 | ||
1525 | static int packed_reflog_expire(struct ref_store *ref_store, | |
1526 | const char *refname, const unsigned char *sha1, | |
1527 | unsigned int flags, | |
1528 | reflog_expiry_prepare_fn prepare_fn, | |
1529 | reflog_expiry_should_prune_fn should_prune_fn, | |
1530 | reflog_expiry_cleanup_fn cleanup_fn, | |
1531 | void *policy_cb_data) | |
1532 | { | |
1533 | return 0; | |
1534 | } | |
1535 | ||
1536 | struct ref_storage_be refs_be_packed = { | |
1537 | NULL, | |
1538 | "packed", | |
1539 | packed_ref_store_create, | |
1540 | packed_init_db, | |
1541 | packed_transaction_prepare, | |
1542 | packed_transaction_finish, | |
1543 | packed_transaction_abort, | |
1544 | packed_initial_transaction_commit, | |
1545 | ||
1546 | packed_pack_refs, | |
e0cc8ac8 MH |
1547 | packed_create_symref, |
1548 | packed_delete_refs, | |
1549 | packed_rename_ref, | |
1550 | ||
1551 | packed_ref_iterator_begin, | |
1552 | packed_read_raw_ref, | |
1553 | ||
1554 | packed_reflog_iterator_begin, | |
1555 | packed_for_each_reflog_ent, | |
1556 | packed_for_each_reflog_ent_reverse, | |
1557 | packed_reflog_exists, | |
1558 | packed_create_reflog, | |
1559 | packed_delete_reflog, | |
1560 | packed_reflog_expire | |
1561 | }; |