diff: do not use null sha1 as a sentinel value
[git/git.git] / builtin / unpack-objects.c
CommitLineData
64413630 1#include "builtin.h"
bad50dc8 2#include "cache.h"
74536958 3#include "object.h"
8ee378a0 4#include "delta.h"
a733cb60 5#include "pack.h"
8e440259
PE
6#include "blob.h"
7#include "commit.h"
8#include "tag.h"
9#include "tree.h"
b41860bf 10#include "tree-walk.h"
96a02f8f 11#include "progress.h"
2add1e6d 12#include "decorate.h"
b41860bf 13#include "fsck.h"
bad50dc8 14
b41860bf 15static int dry_run, quiet, recover, has_errors, strict;
f18d244a 16static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict] < pack-file";
bad50dc8 17
67e5a5ec
LT
18/* We always read in 4kB chunks. */
19static unsigned char buffer[4096];
d7dd0223
NP
20static unsigned int offset, len;
21static off_t consumed_bytes;
9126f009 22static git_SHA_CTX ctx;
bad50dc8 23
f2898cfa
JH
24/*
25 * When running under --strict mode, objects whose reachability are
26 * suspect are kept in core without getting written in the object
27 * store.
28 */
2add1e6d
MK
29struct obj_buffer {
30 char *buffer;
31 unsigned long size;
32};
33
34static struct decoration obj_decorate;
35
36static struct obj_buffer *lookup_object_buffer(struct object *base)
37{
38 return lookup_decoration(&obj_decorate, base);
39}
40
b41860bf
MK
41static void add_object_buffer(struct object *object, char *buffer, unsigned long size)
42{
43 struct obj_buffer *obj;
44 obj = xcalloc(1, sizeof(struct obj_buffer));
45 obj->buffer = buffer;
46 obj->size = size;
47 if (add_decoration(&obj_decorate, object, obj))
48 die("object %s tried to add buffer twice!", sha1_to_hex(object->sha1));
49}
50
67e5a5ec
LT
51/*
52 * Make sure at least "min" bytes are available in the buffer, and
53 * return the pointer to the buffer.
54 */
79a65697 55static void *fill(int min)
67e5a5ec
LT
56{
57 if (min <= len)
58 return buffer + offset;
67e5a5ec
LT
59 if (min > sizeof(buffer))
60 die("cannot fill %d bytes", min);
61 if (offset) {
9126f009 62 git_SHA1_Update(&ctx, buffer, offset);
79a65697 63 memmove(buffer, buffer + offset, len);
67e5a5ec
LT
64 offset = 0;
65 }
66 do {
8a912bcb 67 ssize_t ret = xread(0, buffer + len, sizeof(buffer) - len);
67e5a5ec
LT
68 if (ret <= 0) {
69 if (!ret)
70 die("early EOF");
d824cbba 71 die_errno("read error on input");
67e5a5ec
LT
72 }
73 len += ret;
74 } while (len < min);
75 return buffer;
76}
74536958 77
67e5a5ec
LT
78static void use(int bytes)
79{
80 if (bytes > len)
81 die("used more bytes than were available");
82 len -= bytes;
83 offset += bytes;
d7dd0223
NP
84
85 /* make sure off_t is sufficiently large not to wrap */
c03c8315 86 if (signed_add_overflows(consumed_bytes, bytes))
d7dd0223 87 die("pack too large for current definition of off_t");
209c554a 88 consumed_bytes += bytes;
67e5a5ec 89}
bad50dc8 90
67e5a5ec 91static void *get_data(unsigned long size)
bad50dc8 92{
ef49a7a0 93 git_zstream stream;
67e5a5ec
LT
94 void *buf = xmalloc(size);
95
67e5a5ec
LT
96 memset(&stream, 0, sizeof(stream));
97
98 stream.next_out = buf;
99 stream.avail_out = size;
100 stream.next_in = fill(1);
101 stream.avail_in = len;
39c68542 102 git_inflate_init(&stream);
67e5a5ec
LT
103
104 for (;;) {
39c68542 105 int ret = git_inflate(&stream, 0);
67e5a5ec
LT
106 use(len - stream.avail_in);
107 if (stream.total_out == size && ret == Z_STREAM_END)
108 break;
f986f2c8
JH
109 if (ret != Z_OK) {
110 error("inflate returned %d\n", ret);
111 free(buf);
112 buf = NULL;
3b67d291 113 if (!recover)
f986f2c8
JH
114 exit(1);
115 has_errors = 1;
116 break;
117 }
67e5a5ec
LT
118 stream.next_in = fill(1);
119 stream.avail_in = len;
120 }
39c68542 121 git_inflate_end(&stream);
67e5a5ec 122 return buf;
bad50dc8
LT
123}
124
67e5a5ec
LT
125struct delta_info {
126 unsigned char base_sha1[20];
d7dd0223
NP
127 unsigned nr;
128 off_t base_offset;
67e5a5ec
LT
129 unsigned long size;
130 void *delta;
131 struct delta_info *next;
132};
133
134static struct delta_info *delta_list;
135
209c554a 136static void add_delta_to_list(unsigned nr, unsigned const char *base_sha1,
d7dd0223 137 off_t base_offset,
209c554a 138 void *delta, unsigned long size)
bad50dc8 139{
67e5a5ec 140 struct delta_info *info = xmalloc(sizeof(*info));
bad50dc8 141
e702496e 142 hashcpy(info->base_sha1, base_sha1);
209c554a 143 info->base_offset = base_offset;
67e5a5ec
LT
144 info->size = size;
145 info->delta = delta;
209c554a 146 info->nr = nr;
67e5a5ec
LT
147 info->next = delta_list;
148 delta_list = info;
bad50dc8
LT
149}
150
209c554a 151struct obj_info {
d7dd0223 152 off_t offset;
209c554a 153 unsigned char sha1[20];
b41860bf 154 struct object *obj;
209c554a
NP
155};
156
b41860bf
MK
157#define FLAG_OPEN (1u<<20)
158#define FLAG_WRITTEN (1u<<21)
159
209c554a 160static struct obj_info *obj_list;
2af202be 161static unsigned nr_objects;
b41860bf 162
f2898cfa
JH
163/*
164 * Called only from check_object() after it verified this object
165 * is Ok.
166 */
b41860bf
MK
167static void write_cached_object(struct object *obj)
168{
169 unsigned char sha1[20];
170 struct obj_buffer *obj_buf = lookup_object_buffer(obj);
171 if (write_sha1_file(obj_buf->buffer, obj_buf->size, typename(obj->type), sha1) < 0)
172 die("failed to write object %s", sha1_to_hex(obj->sha1));
173 obj->flags |= FLAG_WRITTEN;
174}
175
f2898cfa
JH
176/*
177 * At the very end of the processing, write_rest() scans the objects
178 * that have reachability requirements and calls this function.
179 * Verify its reachability and validity recursively and write it out.
180 */
b41860bf
MK
181static int check_object(struct object *obj, int type, void *data)
182{
183 if (!obj)
9a217391 184 return 1;
b41860bf
MK
185
186 if (obj->flags & FLAG_WRITTEN)
9a217391 187 return 0;
b41860bf
MK
188
189 if (type != OBJ_ANY && obj->type != type)
190 die("object type mismatch");
191
192 if (!(obj->flags & FLAG_OPEN)) {
193 unsigned long size;
194 int type = sha1_object_info(obj->sha1, &size);
195 if (type != obj->type || type <= 0)
196 die("object of unexpected type");
197 obj->flags |= FLAG_WRITTEN;
9a217391 198 return 0;
b41860bf
MK
199 }
200
201 if (fsck_object(obj, 1, fsck_error_function))
202 die("Error in object");
ab36d06f 203 if (fsck_walk(obj, check_object, NULL))
b41860bf
MK
204 die("Error on reachable objects of %s", sha1_to_hex(obj->sha1));
205 write_cached_object(obj);
9a217391 206 return 0;
b41860bf
MK
207}
208
209static void write_rest(void)
210{
211 unsigned i;
9a217391
JH
212 for (i = 0; i < nr_objects; i++) {
213 if (obj_list[i].obj)
ab36d06f 214 check_object(obj_list[i].obj, OBJ_ANY, NULL);
9a217391 215 }
b41860bf 216}
67e5a5ec 217
21666f1a
NP
218static void added_object(unsigned nr, enum object_type type,
219 void *data, unsigned long size);
209c554a 220
f2898cfa
JH
221/*
222 * Write out nr-th object from the list, now we know the contents
223 * of it. Under --strict, this buffers structured objects in-core,
224 * to be checked at the end.
225 */
21666f1a
NP
226static void write_object(unsigned nr, enum object_type type,
227 void *buf, unsigned long size)
cca7081a 228{
b41860bf
MK
229 if (!strict) {
230 if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
231 die("failed to write object");
f2898cfa 232 added_object(nr, type, buf, size);
b41860bf 233 free(buf);
f2898cfa 234 obj_list[nr].obj = NULL;
b41860bf
MK
235 } else if (type == OBJ_BLOB) {
236 struct blob *blob;
237 if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
238 die("failed to write object");
f2898cfa 239 added_object(nr, type, buf, size);
b41860bf
MK
240 free(buf);
241
242 blob = lookup_blob(obj_list[nr].sha1);
243 if (blob)
244 blob->object.flags |= FLAG_WRITTEN;
245 else
246 die("invalid blob object");
f2898cfa 247 obj_list[nr].obj = NULL;
b41860bf
MK
248 } else {
249 struct object *obj;
250 int eaten;
251 hash_sha1_file(buf, size, typename(type), obj_list[nr].sha1);
f2898cfa 252 added_object(nr, type, buf, size);
b41860bf
MK
253 obj = parse_object_buffer(obj_list[nr].sha1, type, size, buf, &eaten);
254 if (!obj)
255 die("invalid %s", typename(type));
b41860bf
MK
256 add_object_buffer(obj, buf, size);
257 obj->flags |= FLAG_OPEN;
258 obj_list[nr].obj = obj;
259 }
cca7081a
LT
260}
261
21666f1a 262static void resolve_delta(unsigned nr, enum object_type type,
f986f2c8
JH
263 void *base, unsigned long base_size,
264 void *delta, unsigned long delta_size)
bad50dc8 265{
67e5a5ec
LT
266 void *result;
267 unsigned long result_size;
bad50dc8 268
67e5a5ec
LT
269 result = patch_delta(base, base_size,
270 delta, delta_size,
271 &result_size);
272 if (!result)
273 die("failed to apply delta");
274 free(delta);
21666f1a 275 write_object(nr, type, result, result_size);
bad50dc8
LT
276}
277
f2898cfa
JH
278/*
279 * We now know the contents of an object (which is nr-th in the pack);
280 * resolve all the deltified objects that are based on it.
281 */
21666f1a
NP
282static void added_object(unsigned nr, enum object_type type,
283 void *data, unsigned long size)
74536958 284{
67e5a5ec
LT
285 struct delta_info **p = &delta_list;
286 struct delta_info *info;
287
288 while ((info = *p) != NULL) {
209c554a
NP
289 if (!hashcmp(info->base_sha1, obj_list[nr].sha1) ||
290 info->base_offset == obj_list[nr].offset) {
67e5a5ec
LT
291 *p = info->next;
292 p = &delta_list;
209c554a
NP
293 resolve_delta(info->nr, type, data, size,
294 info->delta, info->size);
67e5a5ec
LT
295 free(info);
296 continue;
297 }
298 p = &info->next;
299 }
300}
301
21666f1a 302static void unpack_non_delta_entry(enum object_type type, unsigned long size,
209c554a 303 unsigned nr)
67e5a5ec
LT
304{
305 void *buf = get_data(size);
8ee378a0 306
f986f2c8 307 if (!dry_run && buf)
21666f1a 308 write_object(nr, type, buf, size);
b41860bf
MK
309 else
310 free(buf);
8ee378a0
JH
311}
312
f2898cfa
JH
313static int resolve_against_held(unsigned nr, const unsigned char *base,
314 void *delta_data, unsigned long delta_size)
315{
316 struct object *obj;
317 struct obj_buffer *obj_buffer;
318 obj = lookup_object(base);
319 if (!obj)
320 return 0;
321 obj_buffer = lookup_object_buffer(obj);
322 if (!obj_buffer)
323 return 0;
324 resolve_delta(nr, obj->type, obj_buffer->buffer,
325 obj_buffer->size, delta_data, delta_size);
326 return 1;
327}
328
21666f1a 329static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
209c554a 330 unsigned nr)
8ee378a0 331{
67e5a5ec
LT
332 void *delta_data, *base;
333 unsigned long base_size;
67e5a5ec 334 unsigned char base_sha1[20];
8ee378a0 335
21666f1a 336 if (type == OBJ_REF_DELTA) {
209c554a
NP
337 hashcpy(base_sha1, fill(20));
338 use(20);
339 delta_data = get_data(delta_size);
340 if (dry_run || !delta_data) {
341 free(delta_data);
342 return;
343 }
f2898cfa
JH
344 if (has_sha1_file(base_sha1))
345 ; /* Ok we have this one */
346 else if (resolve_against_held(nr, base_sha1,
347 delta_data, delta_size))
348 return; /* we are done */
349 else {
350 /* cannot resolve yet --- queue it */
209c554a
NP
351 hashcpy(obj_list[nr].sha1, null_sha1);
352 add_delta_to_list(nr, base_sha1, 0, delta_data, delta_size);
353 return;
354 }
355 } else {
356 unsigned base_found = 0;
357 unsigned char *pack, c;
d7dd0223 358 off_t base_offset;
209c554a 359 unsigned lo, mid, hi;
c4fb06c0 360
209c554a
NP
361 pack = fill(1);
362 c = *pack;
363 use(1);
364 base_offset = c & 127;
365 while (c & 128) {
366 base_offset += 1;
8723f216 367 if (!base_offset || MSB(base_offset, 7))
209c554a
NP
368 die("offset value overflow for delta base object");
369 pack = fill(1);
370 c = *pack;
371 use(1);
372 base_offset = (base_offset << 7) + (c & 127);
373 }
374 base_offset = obj_list[nr].offset - base_offset;
d8f32556
NP
375 if (base_offset <= 0 || base_offset >= obj_list[nr].offset)
376 die("offset value out of bound for delta base object");
8ee378a0 377
209c554a
NP
378 delta_data = get_data(delta_size);
379 if (dry_run || !delta_data) {
380 free(delta_data);
381 return;
382 }
383 lo = 0;
384 hi = nr;
385 while (lo < hi) {
386 mid = (lo + hi)/2;
387 if (base_offset < obj_list[mid].offset) {
388 hi = mid;
389 } else if (base_offset > obj_list[mid].offset) {
390 lo = mid + 1;
391 } else {
392 hashcpy(base_sha1, obj_list[mid].sha1);
393 base_found = !is_null_sha1(base_sha1);
394 break;
395 }
396 }
397 if (!base_found) {
f2898cfa
JH
398 /*
399 * The delta base object is itself a delta that
400 * has not been resolved yet.
401 */
209c554a
NP
402 hashcpy(obj_list[nr].sha1, null_sha1);
403 add_delta_to_list(nr, null_sha1, base_offset, delta_data, delta_size);
404 return;
2add1e6d
MK
405 }
406 }
407
f2898cfa
JH
408 if (resolve_against_held(nr, base_sha1, delta_data, delta_size))
409 return;
209c554a 410
21666f1a 411 base = read_sha1_file(base_sha1, &type, &base_size);
f986f2c8
JH
412 if (!base) {
413 error("failed to read delta-pack base object %s",
414 sha1_to_hex(base_sha1));
3b67d291 415 if (!recover)
f986f2c8
JH
416 exit(1);
417 has_errors = 1;
418 return;
419 }
209c554a 420 resolve_delta(nr, type, base, base_size, delta_data, delta_size);
ee639140 421 free(base);
8ee378a0
JH
422}
423
96a02f8f 424static void unpack_one(unsigned nr)
8ee378a0 425{
01247d87 426 unsigned shift;
48fb7deb
LT
427 unsigned char *pack;
428 unsigned long size, c;
67e5a5ec 429 enum object_type type;
74536958 430
209c554a
NP
431 obj_list[nr].offset = consumed_bytes;
432
67e5a5ec
LT
433 pack = fill(1);
434 c = *pack;
435 use(1);
a733cb60
LT
436 type = (c >> 4) & 7;
437 size = (c & 15);
01247d87 438 shift = 4;
a733cb60 439 while (c & 0x80) {
67e5a5ec 440 pack = fill(1);
209c554a 441 c = *pack;
67e5a5ec 442 use(1);
01247d87
LT
443 size += (c & 0x7f) << shift;
444 shift += 7;
a733cb60 445 }
96a02f8f 446
a733cb60
LT
447 switch (type) {
448 case OBJ_COMMIT:
449 case OBJ_TREE:
450 case OBJ_BLOB:
451 case OBJ_TAG:
209c554a 452 unpack_non_delta_entry(type, size, nr);
a733cb60 453 return;
eb32d236 454 case OBJ_REF_DELTA:
209c554a
NP
455 case OBJ_OFS_DELTA:
456 unpack_delta_entry(type, size, nr);
a733cb60 457 return;
67e5a5ec 458 default:
f986f2c8
JH
459 error("bad object type %d", type);
460 has_errors = 1;
3b67d291 461 if (recover)
f986f2c8
JH
462 return;
463 exit(1);
74536958
LT
464 }
465}
466
74536958
LT
467static void unpack_all(void)
468{
67e5a5ec 469 int i;
dc6a0757 470 struct progress *progress = NULL;
67e5a5ec 471 struct pack_header *hdr = fill(sizeof(struct pack_header));
b41860bf
MK
472
473 nr_objects = ntohl(hdr->hdr_entries);
67e5a5ec
LT
474
475 if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
476 die("bad pack file");
d60fc1c8 477 if (!pack_version_ok(hdr->hdr_version))
6e1c2344
RJ
478 die("unknown pack file version %"PRIu32,
479 ntohl(hdr->hdr_version));
96a02f8f 480 use(sizeof(struct pack_header));
67e5a5ec 481
13aaf148 482 if (!quiet)
dc6a0757 483 progress = start_progress("Unpacking objects", nr_objects);
19d4b416 484 obj_list = xcalloc(nr_objects, sizeof(*obj_list));
96a02f8f
NP
485 for (i = 0; i < nr_objects; i++) {
486 unpack_one(i);
4d4fcc54 487 display_progress(progress, i + 1);
96a02f8f 488 }
4d4fcc54 489 stop_progress(&progress);
96a02f8f 490
67e5a5ec
LT
491 if (delta_list)
492 die("unresolved deltas left after unpacking");
74536958
LT
493}
494
64413630 495int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
bad50dc8
LT
496{
497 int i;
67e5a5ec 498 unsigned char sha1[20];
bad50dc8 499
dae556bd
CC
500 read_replace_refs = 0;
501
ef90d6d4 502 git_config(git_default_config, NULL);
53228a5f 503
476e8011
JH
504 quiet = !isatty(2);
505
bad50dc8
LT
506 for (i = 1 ; i < argc; i++) {
507 const char *arg = argv[i];
508
509 if (*arg == '-') {
74536958
LT
510 if (!strcmp(arg, "-n")) {
511 dry_run = 1;
512 continue;
513 }
d36f7b80
LT
514 if (!strcmp(arg, "-q")) {
515 quiet = 1;
516 continue;
517 }
f986f2c8 518 if (!strcmp(arg, "-r")) {
3b67d291 519 recover = 1;
f986f2c8
JH
520 continue;
521 }
b41860bf
MK
522 if (!strcmp(arg, "--strict")) {
523 strict = 1;
524 continue;
525 }
cc44c765 526 if (!prefixcmp(arg, "--pack_header=")) {
bed006fb
NP
527 struct pack_header *hdr;
528 char *c;
529
530 hdr = (struct pack_header *)buffer;
531 hdr->hdr_signature = htonl(PACK_SIGNATURE);
532 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
533 if (*c != ',')
534 die("bad %s", arg);
535 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
536 if (*c)
537 die("bad %s", arg);
538 len = sizeof(*hdr);
539 continue;
540 }
bad50dc8
LT
541 usage(unpack_usage);
542 }
67e5a5ec
LT
543
544 /* We don't take any non-flag arguments now.. Maybe some day */
bad50dc8 545 usage(unpack_usage);
67e5a5ec 546 }
9126f009 547 git_SHA1_Init(&ctx);
74536958 548 unpack_all();
9126f009
NP
549 git_SHA1_Update(&ctx, buffer, offset);
550 git_SHA1_Final(sha1, &ctx);
b41860bf
MK
551 if (strict)
552 write_rest();
a89fccd2 553 if (hashcmp(fill(20), sha1))
67e5a5ec
LT
554 die("final sha1 did not match");
555 use(20);
556
557 /* Write the last part of the buffer to stdout */
558 while (len) {
1c15afb9
JH
559 int ret = xwrite(1, buffer + offset, len);
560 if (ret <= 0)
67e5a5ec 561 break;
67e5a5ec
LT
562 len -= ret;
563 offset += ret;
564 }
565
566 /* All done */
f986f2c8 567 return has_errors;
bad50dc8 568}