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46bc0e73 HWN |
1 | /* |
2 | Copyright 2020 Google LLC | |
3 | ||
4 | Use of this source code is governed by a BSD-style | |
5 | license that can be found in the LICENSE file or at | |
6 | https://developers.google.com/open-source/licenses/bsd | |
7 | */ | |
8 | ||
9 | #include "reader.h" | |
10 | ||
11 | #include "system.h" | |
12 | #include "block.h" | |
13 | #include "constants.h" | |
14 | #include "generic.h" | |
15 | #include "iter.h" | |
16 | #include "record.h" | |
17 | #include "reftable-error.h" | |
18 | #include "reftable-generic.h" | |
46bc0e73 HWN |
19 | |
20 | uint64_t block_source_size(struct reftable_block_source *source) | |
21 | { | |
22 | return source->ops->size(source->arg); | |
23 | } | |
24 | ||
25 | int block_source_read_block(struct reftable_block_source *source, | |
26 | struct reftable_block *dest, uint64_t off, | |
27 | uint32_t size) | |
28 | { | |
29 | int result = source->ops->read_block(source->arg, dest, off, size); | |
30 | dest->source = *source; | |
31 | return result; | |
32 | } | |
33 | ||
34 | void block_source_close(struct reftable_block_source *source) | |
35 | { | |
36 | if (!source->ops) { | |
37 | return; | |
38 | } | |
39 | ||
40 | source->ops->close(source->arg); | |
41 | source->ops = NULL; | |
42 | } | |
43 | ||
44 | static struct reftable_reader_offsets * | |
45 | reader_offsets_for(struct reftable_reader *r, uint8_t typ) | |
46 | { | |
47 | switch (typ) { | |
48 | case BLOCK_TYPE_REF: | |
49 | return &r->ref_offsets; | |
50 | case BLOCK_TYPE_LOG: | |
51 | return &r->log_offsets; | |
52 | case BLOCK_TYPE_OBJ: | |
53 | return &r->obj_offsets; | |
54 | } | |
55 | abort(); | |
56 | } | |
57 | ||
58 | static int reader_get_block(struct reftable_reader *r, | |
59 | struct reftable_block *dest, uint64_t off, | |
60 | uint32_t sz) | |
61 | { | |
62 | if (off >= r->size) | |
63 | return 0; | |
64 | ||
65 | if (off + sz > r->size) { | |
66 | sz = r->size - off; | |
67 | } | |
68 | ||
69 | return block_source_read_block(&r->source, dest, off, sz); | |
70 | } | |
71 | ||
72 | uint32_t reftable_reader_hash_id(struct reftable_reader *r) | |
73 | { | |
74 | return r->hash_id; | |
75 | } | |
76 | ||
77 | const char *reader_name(struct reftable_reader *r) | |
78 | { | |
79 | return r->name; | |
80 | } | |
81 | ||
82 | static int parse_footer(struct reftable_reader *r, uint8_t *footer, | |
83 | uint8_t *header) | |
84 | { | |
85 | uint8_t *f = footer; | |
86 | uint8_t first_block_typ; | |
87 | int err = 0; | |
88 | uint32_t computed_crc; | |
89 | uint32_t file_crc; | |
90 | ||
91 | if (memcmp(f, "REFT", 4)) { | |
92 | err = REFTABLE_FORMAT_ERROR; | |
93 | goto done; | |
94 | } | |
95 | f += 4; | |
96 | ||
97 | if (memcmp(footer, header, header_size(r->version))) { | |
98 | err = REFTABLE_FORMAT_ERROR; | |
99 | goto done; | |
100 | } | |
101 | ||
102 | f++; | |
103 | r->block_size = get_be24(f); | |
104 | ||
105 | f += 3; | |
106 | r->min_update_index = get_be64(f); | |
107 | f += 8; | |
108 | r->max_update_index = get_be64(f); | |
109 | f += 8; | |
110 | ||
111 | if (r->version == 1) { | |
112 | r->hash_id = GIT_SHA1_FORMAT_ID; | |
113 | } else { | |
114 | r->hash_id = get_be32(f); | |
115 | switch (r->hash_id) { | |
116 | case GIT_SHA1_FORMAT_ID: | |
117 | break; | |
118 | case GIT_SHA256_FORMAT_ID: | |
119 | break; | |
120 | default: | |
121 | err = REFTABLE_FORMAT_ERROR; | |
122 | goto done; | |
123 | } | |
124 | f += 4; | |
125 | } | |
126 | ||
127 | r->ref_offsets.index_offset = get_be64(f); | |
128 | f += 8; | |
129 | ||
130 | r->obj_offsets.offset = get_be64(f); | |
131 | f += 8; | |
132 | ||
133 | r->object_id_len = r->obj_offsets.offset & ((1 << 5) - 1); | |
134 | r->obj_offsets.offset >>= 5; | |
135 | ||
136 | r->obj_offsets.index_offset = get_be64(f); | |
137 | f += 8; | |
138 | r->log_offsets.offset = get_be64(f); | |
139 | f += 8; | |
140 | r->log_offsets.index_offset = get_be64(f); | |
141 | f += 8; | |
142 | ||
143 | computed_crc = crc32(0, footer, f - footer); | |
144 | file_crc = get_be32(f); | |
145 | f += 4; | |
146 | if (computed_crc != file_crc) { | |
147 | err = REFTABLE_FORMAT_ERROR; | |
148 | goto done; | |
149 | } | |
150 | ||
151 | first_block_typ = header[header_size(r->version)]; | |
152 | r->ref_offsets.is_present = (first_block_typ == BLOCK_TYPE_REF); | |
153 | r->ref_offsets.offset = 0; | |
154 | r->log_offsets.is_present = (first_block_typ == BLOCK_TYPE_LOG || | |
155 | r->log_offsets.offset > 0); | |
156 | r->obj_offsets.is_present = r->obj_offsets.offset > 0; | |
eff5832b HWN |
157 | if (r->obj_offsets.is_present && !r->object_id_len) { |
158 | err = REFTABLE_FORMAT_ERROR; | |
159 | goto done; | |
160 | } | |
161 | ||
46bc0e73 HWN |
162 | err = 0; |
163 | done: | |
164 | return err; | |
165 | } | |
166 | ||
167 | int init_reader(struct reftable_reader *r, struct reftable_block_source *source, | |
168 | const char *name) | |
169 | { | |
170 | struct reftable_block footer = { NULL }; | |
171 | struct reftable_block header = { NULL }; | |
172 | int err = 0; | |
173 | uint64_t file_size = block_source_size(source); | |
174 | ||
175 | /* Need +1 to read type of first block. */ | |
176 | uint32_t read_size = header_size(2) + 1; /* read v2 because it's larger. */ | |
177 | memset(r, 0, sizeof(struct reftable_reader)); | |
178 | ||
179 | if (read_size > file_size) { | |
180 | err = REFTABLE_FORMAT_ERROR; | |
181 | goto done; | |
182 | } | |
183 | ||
184 | err = block_source_read_block(source, &header, 0, read_size); | |
185 | if (err != read_size) { | |
186 | err = REFTABLE_IO_ERROR; | |
187 | goto done; | |
188 | } | |
189 | ||
190 | if (memcmp(header.data, "REFT", 4)) { | |
191 | err = REFTABLE_FORMAT_ERROR; | |
192 | goto done; | |
193 | } | |
194 | r->version = header.data[4]; | |
195 | if (r->version != 1 && r->version != 2) { | |
196 | err = REFTABLE_FORMAT_ERROR; | |
197 | goto done; | |
198 | } | |
199 | ||
200 | r->size = file_size - footer_size(r->version); | |
201 | r->source = *source; | |
202 | r->name = xstrdup(name); | |
203 | r->hash_id = 0; | |
204 | ||
205 | err = block_source_read_block(source, &footer, r->size, | |
206 | footer_size(r->version)); | |
207 | if (err != footer_size(r->version)) { | |
208 | err = REFTABLE_IO_ERROR; | |
209 | goto done; | |
210 | } | |
211 | ||
212 | err = parse_footer(r, footer.data, header.data); | |
213 | done: | |
214 | reftable_block_done(&footer); | |
215 | reftable_block_done(&header); | |
216 | return err; | |
217 | } | |
218 | ||
219 | struct table_iter { | |
220 | struct reftable_reader *r; | |
221 | uint8_t typ; | |
222 | uint64_t block_off; | |
223 | struct block_iter bi; | |
224 | int is_finished; | |
225 | }; | |
a8305bc6 PS |
226 | #define TABLE_ITER_INIT { \ |
227 | .bi = BLOCK_ITER_INIT \ | |
228 | } | |
46bc0e73 HWN |
229 | |
230 | static void table_iter_copy_from(struct table_iter *dest, | |
231 | struct table_iter *src) | |
232 | { | |
233 | dest->r = src->r; | |
234 | dest->typ = src->typ; | |
235 | dest->block_off = src->block_off; | |
236 | dest->is_finished = src->is_finished; | |
237 | block_iter_copy_from(&dest->bi, &src->bi); | |
238 | } | |
239 | ||
240 | static int table_iter_next_in_block(struct table_iter *ti, | |
241 | struct reftable_record *rec) | |
242 | { | |
243 | int res = block_iter_next(&ti->bi, rec); | |
244 | if (res == 0 && reftable_record_type(rec) == BLOCK_TYPE_REF) { | |
66c0daba | 245 | rec->u.ref.update_index += ti->r->min_update_index; |
46bc0e73 HWN |
246 | } |
247 | ||
248 | return res; | |
249 | } | |
250 | ||
251 | static void table_iter_block_done(struct table_iter *ti) | |
252 | { | |
253 | if (!ti->bi.br) { | |
254 | return; | |
255 | } | |
256 | reftable_block_done(&ti->bi.br->block); | |
257 | FREE_AND_NULL(ti->bi.br); | |
258 | ||
259 | ti->bi.last_key.len = 0; | |
260 | ti->bi.next_off = 0; | |
261 | } | |
262 | ||
263 | static int32_t extract_block_size(uint8_t *data, uint8_t *typ, uint64_t off, | |
264 | int version) | |
265 | { | |
266 | int32_t result = 0; | |
267 | ||
268 | if (off == 0) { | |
269 | data += header_size(version); | |
270 | } | |
271 | ||
272 | *typ = data[0]; | |
273 | if (reftable_is_block_type(*typ)) { | |
274 | result = get_be24(data + 1); | |
275 | } | |
276 | return result; | |
277 | } | |
278 | ||
279 | int reader_init_block_reader(struct reftable_reader *r, struct block_reader *br, | |
280 | uint64_t next_off, uint8_t want_typ) | |
281 | { | |
282 | int32_t guess_block_size = r->block_size ? r->block_size : | |
283 | DEFAULT_BLOCK_SIZE; | |
284 | struct reftable_block block = { NULL }; | |
285 | uint8_t block_typ = 0; | |
286 | int err = 0; | |
287 | uint32_t header_off = next_off ? 0 : header_size(r->version); | |
288 | int32_t block_size = 0; | |
289 | ||
290 | if (next_off >= r->size) | |
291 | return 1; | |
292 | ||
293 | err = reader_get_block(r, &block, next_off, guess_block_size); | |
294 | if (err < 0) | |
24d4d38c | 295 | goto done; |
46bc0e73 HWN |
296 | |
297 | block_size = extract_block_size(block.data, &block_typ, next_off, | |
298 | r->version); | |
24d4d38c HWN |
299 | if (block_size < 0) { |
300 | err = block_size; | |
301 | goto done; | |
302 | } | |
46bc0e73 | 303 | if (want_typ != BLOCK_TYPE_ANY && block_typ != want_typ) { |
24d4d38c HWN |
304 | err = 1; |
305 | goto done; | |
46bc0e73 HWN |
306 | } |
307 | ||
308 | if (block_size > guess_block_size) { | |
309 | reftable_block_done(&block); | |
310 | err = reader_get_block(r, &block, next_off, block_size); | |
311 | if (err < 0) { | |
24d4d38c | 312 | goto done; |
46bc0e73 HWN |
313 | } |
314 | } | |
315 | ||
24d4d38c HWN |
316 | err = block_reader_init(br, &block, header_off, r->block_size, |
317 | hash_size(r->hash_id)); | |
318 | done: | |
319 | reftable_block_done(&block); | |
320 | ||
321 | return err; | |
46bc0e73 HWN |
322 | } |
323 | ||
324 | static int table_iter_next_block(struct table_iter *dest, | |
325 | struct table_iter *src) | |
326 | { | |
327 | uint64_t next_block_off = src->block_off + src->bi.br->full_block_size; | |
328 | struct block_reader br = { 0 }; | |
329 | int err = 0; | |
330 | ||
331 | dest->r = src->r; | |
332 | dest->typ = src->typ; | |
333 | dest->block_off = next_block_off; | |
334 | ||
335 | err = reader_init_block_reader(src->r, &br, next_block_off, src->typ); | |
336 | if (err > 0) { | |
337 | dest->is_finished = 1; | |
338 | return 1; | |
339 | } | |
340 | if (err != 0) | |
341 | return err; | |
342 | else { | |
343 | struct block_reader *brp = | |
344 | reftable_malloc(sizeof(struct block_reader)); | |
345 | *brp = br; | |
346 | ||
347 | dest->is_finished = 0; | |
348 | block_reader_start(brp, &dest->bi); | |
349 | } | |
350 | return 0; | |
351 | } | |
352 | ||
353 | static int table_iter_next(struct table_iter *ti, struct reftable_record *rec) | |
354 | { | |
355 | if (reftable_record_type(rec) != ti->typ) | |
356 | return REFTABLE_API_ERROR; | |
357 | ||
358 | while (1) { | |
359 | struct table_iter next = TABLE_ITER_INIT; | |
c68ca7ab PS |
360 | int err; |
361 | ||
362 | if (ti->is_finished) | |
46bc0e73 | 363 | return 1; |
46bc0e73 | 364 | |
c68ca7ab PS |
365 | /* |
366 | * Check whether the current block still has more records. If | |
367 | * so, return it. If the iterator returns positive then the | |
368 | * current block has been exhausted. | |
369 | */ | |
46bc0e73 | 370 | err = table_iter_next_in_block(ti, rec); |
c68ca7ab | 371 | if (err <= 0) |
46bc0e73 | 372 | return err; |
46bc0e73 | 373 | |
c68ca7ab PS |
374 | /* |
375 | * Otherwise, we need to continue to the next block in the | |
376 | * table and retry. If there are no more blocks then the | |
377 | * iterator is drained. | |
378 | */ | |
46bc0e73 | 379 | err = table_iter_next_block(&next, ti); |
46bc0e73 | 380 | table_iter_block_done(ti); |
c68ca7ab PS |
381 | if (err) { |
382 | ti->is_finished = 1; | |
46bc0e73 HWN |
383 | return err; |
384 | } | |
c68ca7ab | 385 | |
46bc0e73 HWN |
386 | table_iter_copy_from(ti, &next); |
387 | block_iter_close(&next.bi); | |
388 | } | |
389 | } | |
390 | ||
391 | static int table_iter_next_void(void *ti, struct reftable_record *rec) | |
392 | { | |
393 | return table_iter_next(ti, rec); | |
394 | } | |
395 | ||
396 | static void table_iter_close(void *p) | |
397 | { | |
398 | struct table_iter *ti = p; | |
399 | table_iter_block_done(ti); | |
400 | block_iter_close(&ti->bi); | |
401 | } | |
402 | ||
403 | static struct reftable_iterator_vtable table_iter_vtable = { | |
404 | .next = &table_iter_next_void, | |
405 | .close = &table_iter_close, | |
406 | }; | |
407 | ||
408 | static void iterator_from_table_iter(struct reftable_iterator *it, | |
409 | struct table_iter *ti) | |
410 | { | |
411 | assert(!it->ops); | |
412 | it->iter_arg = ti; | |
413 | it->ops = &table_iter_vtable; | |
414 | } | |
415 | ||
416 | static int reader_table_iter_at(struct reftable_reader *r, | |
417 | struct table_iter *ti, uint64_t off, | |
418 | uint8_t typ) | |
419 | { | |
420 | struct block_reader br = { 0 }; | |
421 | struct block_reader *brp = NULL; | |
422 | ||
423 | int err = reader_init_block_reader(r, &br, off, typ); | |
424 | if (err != 0) | |
425 | return err; | |
426 | ||
427 | brp = reftable_malloc(sizeof(struct block_reader)); | |
428 | *brp = br; | |
429 | ti->r = r; | |
430 | ti->typ = block_reader_type(brp); | |
431 | ti->block_off = off; | |
432 | block_reader_start(brp, &ti->bi); | |
433 | return 0; | |
434 | } | |
435 | ||
436 | static int reader_start(struct reftable_reader *r, struct table_iter *ti, | |
437 | uint8_t typ, int index) | |
438 | { | |
439 | struct reftable_reader_offsets *offs = reader_offsets_for(r, typ); | |
440 | uint64_t off = offs->offset; | |
441 | if (index) { | |
442 | off = offs->index_offset; | |
443 | if (off == 0) { | |
444 | return 1; | |
445 | } | |
446 | typ = BLOCK_TYPE_INDEX; | |
447 | } | |
448 | ||
449 | return reader_table_iter_at(r, ti, off, typ); | |
450 | } | |
451 | ||
21a40847 | 452 | static int reader_seek_linear(struct table_iter *ti, |
46bc0e73 HWN |
453 | struct reftable_record *want) |
454 | { | |
46bc0e73 HWN |
455 | struct strbuf want_key = STRBUF_INIT; |
456 | struct strbuf got_key = STRBUF_INIT; | |
457 | struct table_iter next = TABLE_ITER_INIT; | |
3ddef475 | 458 | struct reftable_record rec; |
46bc0e73 HWN |
459 | int err = -1; |
460 | ||
3ddef475 | 461 | reftable_record_init(&rec, reftable_record_type(want)); |
46bc0e73 HWN |
462 | reftable_record_key(want, &want_key); |
463 | ||
464 | while (1) { | |
465 | err = table_iter_next_block(&next, ti); | |
466 | if (err < 0) | |
467 | goto done; | |
468 | ||
469 | if (err > 0) { | |
470 | break; | |
471 | } | |
472 | ||
473 | err = block_reader_first_key(next.bi.br, &got_key); | |
474 | if (err < 0) | |
475 | goto done; | |
476 | ||
477 | if (strbuf_cmp(&got_key, &want_key) > 0) { | |
478 | table_iter_block_done(&next); | |
479 | break; | |
480 | } | |
481 | ||
482 | table_iter_block_done(ti); | |
483 | table_iter_copy_from(ti, &next); | |
484 | } | |
485 | ||
486 | err = block_iter_seek(&ti->bi, &want_key); | |
487 | if (err < 0) | |
488 | goto done; | |
489 | err = 0; | |
490 | ||
491 | done: | |
492 | block_iter_close(&next.bi); | |
66c0daba | 493 | reftable_record_release(&rec); |
46bc0e73 HWN |
494 | strbuf_release(&want_key); |
495 | strbuf_release(&got_key); | |
496 | return err; | |
497 | } | |
498 | ||
499 | static int reader_seek_indexed(struct reftable_reader *r, | |
500 | struct reftable_iterator *it, | |
501 | struct reftable_record *rec) | |
502 | { | |
66c0daba HWN |
503 | struct reftable_record want_index = { |
504 | .type = BLOCK_TYPE_INDEX, .u.idx = { .last_key = STRBUF_INIT } | |
505 | }; | |
506 | struct reftable_record index_result = { | |
507 | .type = BLOCK_TYPE_INDEX, | |
508 | .u.idx = { .last_key = STRBUF_INIT }, | |
509 | }; | |
46bc0e73 HWN |
510 | struct table_iter index_iter = TABLE_ITER_INIT; |
511 | struct table_iter next = TABLE_ITER_INIT; | |
512 | int err = 0; | |
513 | ||
66c0daba | 514 | reftable_record_key(rec, &want_index.u.idx.last_key); |
46bc0e73 HWN |
515 | err = reader_start(r, &index_iter, reftable_record_type(rec), 1); |
516 | if (err < 0) | |
517 | goto done; | |
518 | ||
4950acae PS |
519 | /* |
520 | * The index may consist of multiple levels, where each level may have | |
521 | * multiple index blocks. We start by doing a linear search in the | |
522 | * highest layer that identifies the relevant index block as well as | |
523 | * the record inside that block that corresponds to our wanted key. | |
524 | */ | |
21a40847 | 525 | err = reader_seek_linear(&index_iter, &want_index); |
d55fc512 PS |
526 | if (err < 0) |
527 | goto done; | |
528 | ||
4950acae PS |
529 | /* |
530 | * Traverse down the levels until we find a non-index entry. | |
531 | */ | |
46bc0e73 | 532 | while (1) { |
4950acae PS |
533 | /* |
534 | * In case we seek a record that does not exist the index iter | |
535 | * will tell us that the iterator is over. This works because | |
536 | * the last index entry of the current level will contain the | |
537 | * last key it knows about. So in case our seeked key is larger | |
538 | * than the last indexed key we know that it won't exist. | |
539 | * | |
540 | * There is one subtlety in the layout of the index section | |
541 | * that makes this work as expected: the highest-level index is | |
542 | * at end of the section and will point backwards and thus we | |
543 | * start reading from the end of the index section, not the | |
544 | * beginning. | |
545 | * | |
546 | * If that wasn't the case and the order was reversed then the | |
547 | * linear seek would seek into the lower levels and traverse | |
548 | * all levels of the index only to find out that the key does | |
549 | * not exist. | |
550 | */ | |
66c0daba | 551 | err = table_iter_next(&index_iter, &index_result); |
46bc0e73 HWN |
552 | table_iter_block_done(&index_iter); |
553 | if (err != 0) | |
554 | goto done; | |
555 | ||
66c0daba HWN |
556 | err = reader_table_iter_at(r, &next, index_result.u.idx.offset, |
557 | 0); | |
46bc0e73 HWN |
558 | if (err != 0) |
559 | goto done; | |
560 | ||
66c0daba | 561 | err = block_iter_seek(&next.bi, &want_index.u.idx.last_key); |
46bc0e73 HWN |
562 | if (err < 0) |
563 | goto done; | |
564 | ||
565 | if (next.typ == reftable_record_type(rec)) { | |
566 | err = 0; | |
567 | break; | |
568 | } | |
569 | ||
570 | if (next.typ != BLOCK_TYPE_INDEX) { | |
571 | err = REFTABLE_FORMAT_ERROR; | |
572 | break; | |
573 | } | |
574 | ||
575 | table_iter_copy_from(&index_iter, &next); | |
576 | } | |
577 | ||
578 | if (err == 0) { | |
579 | struct table_iter empty = TABLE_ITER_INIT; | |
b4ff12c8 | 580 | struct table_iter *malloced = reftable_calloc(1, sizeof(*malloced)); |
46bc0e73 HWN |
581 | *malloced = empty; |
582 | table_iter_copy_from(malloced, &next); | |
583 | iterator_from_table_iter(it, malloced); | |
584 | } | |
585 | done: | |
586 | block_iter_close(&next.bi); | |
587 | table_iter_close(&index_iter); | |
66c0daba HWN |
588 | reftable_record_release(&want_index); |
589 | reftable_record_release(&index_result); | |
46bc0e73 HWN |
590 | return err; |
591 | } | |
592 | ||
593 | static int reader_seek_internal(struct reftable_reader *r, | |
594 | struct reftable_iterator *it, | |
595 | struct reftable_record *rec) | |
596 | { | |
597 | struct reftable_reader_offsets *offs = | |
598 | reader_offsets_for(r, reftable_record_type(rec)); | |
599 | uint64_t idx = offs->index_offset; | |
600 | struct table_iter ti = TABLE_ITER_INIT; | |
601 | int err = 0; | |
602 | if (idx > 0) | |
603 | return reader_seek_indexed(r, it, rec); | |
604 | ||
605 | err = reader_start(r, &ti, reftable_record_type(rec), 0); | |
606 | if (err < 0) | |
607 | return err; | |
21a40847 | 608 | err = reader_seek_linear(&ti, rec); |
46bc0e73 HWN |
609 | if (err < 0) |
610 | return err; | |
611 | else { | |
612 | struct table_iter *p = | |
613 | reftable_malloc(sizeof(struct table_iter)); | |
614 | *p = ti; | |
615 | iterator_from_table_iter(it, p); | |
616 | } | |
617 | ||
618 | return 0; | |
619 | } | |
620 | ||
621 | static int reader_seek(struct reftable_reader *r, struct reftable_iterator *it, | |
622 | struct reftable_record *rec) | |
623 | { | |
624 | uint8_t typ = reftable_record_type(rec); | |
625 | ||
626 | struct reftable_reader_offsets *offs = reader_offsets_for(r, typ); | |
627 | if (!offs->is_present) { | |
628 | iterator_set_empty(it); | |
629 | return 0; | |
630 | } | |
631 | ||
632 | return reader_seek_internal(r, it, rec); | |
633 | } | |
634 | ||
635 | int reftable_reader_seek_ref(struct reftable_reader *r, | |
636 | struct reftable_iterator *it, const char *name) | |
637 | { | |
66c0daba HWN |
638 | struct reftable_record rec = { |
639 | .type = BLOCK_TYPE_REF, | |
640 | .u.ref = { | |
641 | .refname = (char *)name, | |
642 | }, | |
46bc0e73 | 643 | }; |
46bc0e73 HWN |
644 | return reader_seek(r, it, &rec); |
645 | } | |
646 | ||
647 | int reftable_reader_seek_log_at(struct reftable_reader *r, | |
648 | struct reftable_iterator *it, const char *name, | |
649 | uint64_t update_index) | |
650 | { | |
66c0daba HWN |
651 | struct reftable_record rec = { .type = BLOCK_TYPE_LOG, |
652 | .u.log = { | |
653 | .refname = (char *)name, | |
654 | .update_index = update_index, | |
655 | } }; | |
46bc0e73 HWN |
656 | return reader_seek(r, it, &rec); |
657 | } | |
658 | ||
659 | int reftable_reader_seek_log(struct reftable_reader *r, | |
660 | struct reftable_iterator *it, const char *name) | |
661 | { | |
662 | uint64_t max = ~((uint64_t)0); | |
663 | return reftable_reader_seek_log_at(r, it, name, max); | |
664 | } | |
665 | ||
666 | void reader_close(struct reftable_reader *r) | |
667 | { | |
668 | block_source_close(&r->source); | |
669 | FREE_AND_NULL(r->name); | |
670 | } | |
671 | ||
672 | int reftable_new_reader(struct reftable_reader **p, | |
673 | struct reftable_block_source *src, char const *name) | |
674 | { | |
b4ff12c8 | 675 | struct reftable_reader *rd = reftable_calloc(1, sizeof(*rd)); |
46bc0e73 HWN |
676 | int err = init_reader(rd, src, name); |
677 | if (err == 0) { | |
678 | *p = rd; | |
679 | } else { | |
680 | block_source_close(src); | |
681 | reftable_free(rd); | |
682 | } | |
683 | return err; | |
684 | } | |
685 | ||
686 | void reftable_reader_free(struct reftable_reader *r) | |
687 | { | |
33e92243 HWN |
688 | if (!r) |
689 | return; | |
46bc0e73 HWN |
690 | reader_close(r); |
691 | reftable_free(r); | |
692 | } | |
693 | ||
694 | static int reftable_reader_refs_for_indexed(struct reftable_reader *r, | |
695 | struct reftable_iterator *it, | |
696 | uint8_t *oid) | |
697 | { | |
66c0daba HWN |
698 | struct reftable_record want = { |
699 | .type = BLOCK_TYPE_OBJ, | |
700 | .u.obj = { | |
701 | .hash_prefix = oid, | |
702 | .hash_prefix_len = r->object_id_len, | |
703 | }, | |
46bc0e73 | 704 | }; |
46bc0e73 | 705 | struct reftable_iterator oit = { NULL }; |
66c0daba HWN |
706 | struct reftable_record got = { |
707 | .type = BLOCK_TYPE_OBJ, | |
708 | .u.obj = { 0 }, | |
709 | }; | |
46bc0e73 HWN |
710 | int err = 0; |
711 | struct indexed_table_ref_iter *itr = NULL; | |
712 | ||
713 | /* Look through the reverse index. */ | |
66c0daba | 714 | err = reader_seek(r, &oit, &want); |
46bc0e73 HWN |
715 | if (err != 0) |
716 | goto done; | |
717 | ||
718 | /* read out the reftable_obj_record */ | |
66c0daba | 719 | err = iterator_next(&oit, &got); |
46bc0e73 HWN |
720 | if (err < 0) |
721 | goto done; | |
722 | ||
66c0daba HWN |
723 | if (err > 0 || memcmp(want.u.obj.hash_prefix, got.u.obj.hash_prefix, |
724 | r->object_id_len)) { | |
46bc0e73 HWN |
725 | /* didn't find it; return empty iterator */ |
726 | iterator_set_empty(it); | |
727 | err = 0; | |
728 | goto done; | |
729 | } | |
730 | ||
731 | err = new_indexed_table_ref_iter(&itr, r, oid, hash_size(r->hash_id), | |
66c0daba HWN |
732 | got.u.obj.offsets, |
733 | got.u.obj.offset_len); | |
46bc0e73 HWN |
734 | if (err < 0) |
735 | goto done; | |
66c0daba | 736 | got.u.obj.offsets = NULL; |
46bc0e73 HWN |
737 | iterator_from_indexed_table_ref_iter(it, itr); |
738 | ||
739 | done: | |
740 | reftable_iterator_destroy(&oit); | |
66c0daba | 741 | reftable_record_release(&got); |
46bc0e73 HWN |
742 | return err; |
743 | } | |
744 | ||
745 | static int reftable_reader_refs_for_unindexed(struct reftable_reader *r, | |
746 | struct reftable_iterator *it, | |
747 | uint8_t *oid) | |
748 | { | |
749 | struct table_iter ti_empty = TABLE_ITER_INIT; | |
b4ff12c8 | 750 | struct table_iter *ti = reftable_calloc(1, sizeof(*ti)); |
46bc0e73 HWN |
751 | struct filtering_ref_iterator *filter = NULL; |
752 | struct filtering_ref_iterator empty = FILTERING_REF_ITERATOR_INIT; | |
753 | int oid_len = hash_size(r->hash_id); | |
754 | int err; | |
755 | ||
756 | *ti = ti_empty; | |
757 | err = reader_start(r, ti, BLOCK_TYPE_REF, 0); | |
758 | if (err < 0) { | |
759 | reftable_free(ti); | |
760 | return err; | |
761 | } | |
762 | ||
763 | filter = reftable_malloc(sizeof(struct filtering_ref_iterator)); | |
764 | *filter = empty; | |
765 | ||
766 | strbuf_add(&filter->oid, oid, oid_len); | |
767 | reftable_table_from_reader(&filter->tab, r); | |
768 | filter->double_check = 0; | |
769 | iterator_from_table_iter(&filter->it, ti); | |
770 | ||
771 | iterator_from_filtering_ref_iterator(it, filter); | |
772 | return 0; | |
773 | } | |
774 | ||
775 | int reftable_reader_refs_for(struct reftable_reader *r, | |
776 | struct reftable_iterator *it, uint8_t *oid) | |
777 | { | |
778 | if (r->obj_offsets.is_present) | |
779 | return reftable_reader_refs_for_indexed(r, it, oid); | |
780 | return reftable_reader_refs_for_unindexed(r, it, oid); | |
781 | } | |
782 | ||
783 | uint64_t reftable_reader_max_update_index(struct reftable_reader *r) | |
784 | { | |
785 | return r->max_update_index; | |
786 | } | |
787 | ||
788 | uint64_t reftable_reader_min_update_index(struct reftable_reader *r) | |
789 | { | |
790 | return r->min_update_index; | |
791 | } | |
792 | ||
793 | /* generic table interface. */ | |
794 | ||
795 | static int reftable_reader_seek_void(void *tab, struct reftable_iterator *it, | |
796 | struct reftable_record *rec) | |
797 | { | |
798 | return reader_seek(tab, it, rec); | |
799 | } | |
800 | ||
801 | static uint32_t reftable_reader_hash_id_void(void *tab) | |
802 | { | |
803 | return reftable_reader_hash_id(tab); | |
804 | } | |
805 | ||
806 | static uint64_t reftable_reader_min_update_index_void(void *tab) | |
807 | { | |
808 | return reftable_reader_min_update_index(tab); | |
809 | } | |
810 | ||
811 | static uint64_t reftable_reader_max_update_index_void(void *tab) | |
812 | { | |
813 | return reftable_reader_max_update_index(tab); | |
814 | } | |
815 | ||
816 | static struct reftable_table_vtable reader_vtable = { | |
817 | .seek_record = reftable_reader_seek_void, | |
818 | .hash_id = reftable_reader_hash_id_void, | |
819 | .min_update_index = reftable_reader_min_update_index_void, | |
820 | .max_update_index = reftable_reader_max_update_index_void, | |
821 | }; | |
822 | ||
823 | void reftable_table_from_reader(struct reftable_table *tab, | |
824 | struct reftable_reader *reader) | |
825 | { | |
826 | assert(!tab->ops); | |
827 | tab->ops = &reader_vtable; | |
828 | tab->table_arg = reader; | |
829 | } | |
830 | ||
831 | ||
832 | int reftable_reader_print_file(const char *tablename) | |
833 | { | |
834 | struct reftable_block_source src = { NULL }; | |
835 | int err = reftable_block_source_from_file(&src, tablename); | |
836 | struct reftable_reader *r = NULL; | |
837 | struct reftable_table tab = { NULL }; | |
838 | if (err < 0) | |
839 | goto done; | |
840 | ||
841 | err = reftable_new_reader(&r, &src, tablename); | |
842 | if (err < 0) | |
843 | goto done; | |
844 | ||
845 | reftable_table_from_reader(&tab, r); | |
846 | err = reftable_table_print(&tab); | |
847 | done: | |
848 | reftable_reader_free(r); | |
849 | return err; | |
850 | } |