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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; | |
360 | int err = 0; | |
361 | if (ti->is_finished) { | |
362 | return 1; | |
363 | } | |
364 | ||
365 | err = table_iter_next_in_block(ti, rec); | |
366 | if (err <= 0) { | |
367 | return err; | |
368 | } | |
369 | ||
370 | err = table_iter_next_block(&next, ti); | |
371 | if (err != 0) { | |
372 | ti->is_finished = 1; | |
373 | } | |
374 | table_iter_block_done(ti); | |
375 | if (err != 0) { | |
376 | return err; | |
377 | } | |
378 | table_iter_copy_from(ti, &next); | |
379 | block_iter_close(&next.bi); | |
380 | } | |
381 | } | |
382 | ||
383 | static int table_iter_next_void(void *ti, struct reftable_record *rec) | |
384 | { | |
385 | return table_iter_next(ti, rec); | |
386 | } | |
387 | ||
388 | static void table_iter_close(void *p) | |
389 | { | |
390 | struct table_iter *ti = p; | |
391 | table_iter_block_done(ti); | |
392 | block_iter_close(&ti->bi); | |
393 | } | |
394 | ||
395 | static struct reftable_iterator_vtable table_iter_vtable = { | |
396 | .next = &table_iter_next_void, | |
397 | .close = &table_iter_close, | |
398 | }; | |
399 | ||
400 | static void iterator_from_table_iter(struct reftable_iterator *it, | |
401 | struct table_iter *ti) | |
402 | { | |
403 | assert(!it->ops); | |
404 | it->iter_arg = ti; | |
405 | it->ops = &table_iter_vtable; | |
406 | } | |
407 | ||
408 | static int reader_table_iter_at(struct reftable_reader *r, | |
409 | struct table_iter *ti, uint64_t off, | |
410 | uint8_t typ) | |
411 | { | |
412 | struct block_reader br = { 0 }; | |
413 | struct block_reader *brp = NULL; | |
414 | ||
415 | int err = reader_init_block_reader(r, &br, off, typ); | |
416 | if (err != 0) | |
417 | return err; | |
418 | ||
419 | brp = reftable_malloc(sizeof(struct block_reader)); | |
420 | *brp = br; | |
421 | ti->r = r; | |
422 | ti->typ = block_reader_type(brp); | |
423 | ti->block_off = off; | |
424 | block_reader_start(brp, &ti->bi); | |
425 | return 0; | |
426 | } | |
427 | ||
428 | static int reader_start(struct reftable_reader *r, struct table_iter *ti, | |
429 | uint8_t typ, int index) | |
430 | { | |
431 | struct reftable_reader_offsets *offs = reader_offsets_for(r, typ); | |
432 | uint64_t off = offs->offset; | |
433 | if (index) { | |
434 | off = offs->index_offset; | |
435 | if (off == 0) { | |
436 | return 1; | |
437 | } | |
438 | typ = BLOCK_TYPE_INDEX; | |
439 | } | |
440 | ||
441 | return reader_table_iter_at(r, ti, off, typ); | |
442 | } | |
443 | ||
21a40847 | 444 | static int reader_seek_linear(struct table_iter *ti, |
46bc0e73 HWN |
445 | struct reftable_record *want) |
446 | { | |
46bc0e73 HWN |
447 | struct strbuf want_key = STRBUF_INIT; |
448 | struct strbuf got_key = STRBUF_INIT; | |
449 | struct table_iter next = TABLE_ITER_INIT; | |
3ddef475 | 450 | struct reftable_record rec; |
46bc0e73 HWN |
451 | int err = -1; |
452 | ||
3ddef475 | 453 | reftable_record_init(&rec, reftable_record_type(want)); |
46bc0e73 HWN |
454 | reftable_record_key(want, &want_key); |
455 | ||
456 | while (1) { | |
457 | err = table_iter_next_block(&next, ti); | |
458 | if (err < 0) | |
459 | goto done; | |
460 | ||
461 | if (err > 0) { | |
462 | break; | |
463 | } | |
464 | ||
465 | err = block_reader_first_key(next.bi.br, &got_key); | |
466 | if (err < 0) | |
467 | goto done; | |
468 | ||
469 | if (strbuf_cmp(&got_key, &want_key) > 0) { | |
470 | table_iter_block_done(&next); | |
471 | break; | |
472 | } | |
473 | ||
474 | table_iter_block_done(ti); | |
475 | table_iter_copy_from(ti, &next); | |
476 | } | |
477 | ||
478 | err = block_iter_seek(&ti->bi, &want_key); | |
479 | if (err < 0) | |
480 | goto done; | |
481 | err = 0; | |
482 | ||
483 | done: | |
484 | block_iter_close(&next.bi); | |
66c0daba | 485 | reftable_record_release(&rec); |
46bc0e73 HWN |
486 | strbuf_release(&want_key); |
487 | strbuf_release(&got_key); | |
488 | return err; | |
489 | } | |
490 | ||
491 | static int reader_seek_indexed(struct reftable_reader *r, | |
492 | struct reftable_iterator *it, | |
493 | struct reftable_record *rec) | |
494 | { | |
66c0daba HWN |
495 | struct reftable_record want_index = { |
496 | .type = BLOCK_TYPE_INDEX, .u.idx = { .last_key = STRBUF_INIT } | |
497 | }; | |
498 | struct reftable_record index_result = { | |
499 | .type = BLOCK_TYPE_INDEX, | |
500 | .u.idx = { .last_key = STRBUF_INIT }, | |
501 | }; | |
46bc0e73 HWN |
502 | struct table_iter index_iter = TABLE_ITER_INIT; |
503 | struct table_iter next = TABLE_ITER_INIT; | |
504 | int err = 0; | |
505 | ||
66c0daba | 506 | reftable_record_key(rec, &want_index.u.idx.last_key); |
46bc0e73 HWN |
507 | err = reader_start(r, &index_iter, reftable_record_type(rec), 1); |
508 | if (err < 0) | |
509 | goto done; | |
510 | ||
4950acae PS |
511 | /* |
512 | * The index may consist of multiple levels, where each level may have | |
513 | * multiple index blocks. We start by doing a linear search in the | |
514 | * highest layer that identifies the relevant index block as well as | |
515 | * the record inside that block that corresponds to our wanted key. | |
516 | */ | |
21a40847 | 517 | err = reader_seek_linear(&index_iter, &want_index); |
d55fc512 PS |
518 | if (err < 0) |
519 | goto done; | |
520 | ||
4950acae PS |
521 | /* |
522 | * Traverse down the levels until we find a non-index entry. | |
523 | */ | |
46bc0e73 | 524 | while (1) { |
4950acae PS |
525 | /* |
526 | * In case we seek a record that does not exist the index iter | |
527 | * will tell us that the iterator is over. This works because | |
528 | * the last index entry of the current level will contain the | |
529 | * last key it knows about. So in case our seeked key is larger | |
530 | * than the last indexed key we know that it won't exist. | |
531 | * | |
532 | * There is one subtlety in the layout of the index section | |
533 | * that makes this work as expected: the highest-level index is | |
534 | * at end of the section and will point backwards and thus we | |
535 | * start reading from the end of the index section, not the | |
536 | * beginning. | |
537 | * | |
538 | * If that wasn't the case and the order was reversed then the | |
539 | * linear seek would seek into the lower levels and traverse | |
540 | * all levels of the index only to find out that the key does | |
541 | * not exist. | |
542 | */ | |
66c0daba | 543 | err = table_iter_next(&index_iter, &index_result); |
46bc0e73 HWN |
544 | table_iter_block_done(&index_iter); |
545 | if (err != 0) | |
546 | goto done; | |
547 | ||
66c0daba HWN |
548 | err = reader_table_iter_at(r, &next, index_result.u.idx.offset, |
549 | 0); | |
46bc0e73 HWN |
550 | if (err != 0) |
551 | goto done; | |
552 | ||
66c0daba | 553 | err = block_iter_seek(&next.bi, &want_index.u.idx.last_key); |
46bc0e73 HWN |
554 | if (err < 0) |
555 | goto done; | |
556 | ||
557 | if (next.typ == reftable_record_type(rec)) { | |
558 | err = 0; | |
559 | break; | |
560 | } | |
561 | ||
562 | if (next.typ != BLOCK_TYPE_INDEX) { | |
563 | err = REFTABLE_FORMAT_ERROR; | |
564 | break; | |
565 | } | |
566 | ||
567 | table_iter_copy_from(&index_iter, &next); | |
568 | } | |
569 | ||
570 | if (err == 0) { | |
571 | struct table_iter empty = TABLE_ITER_INIT; | |
b4ff12c8 | 572 | struct table_iter *malloced = reftable_calloc(1, sizeof(*malloced)); |
46bc0e73 HWN |
573 | *malloced = empty; |
574 | table_iter_copy_from(malloced, &next); | |
575 | iterator_from_table_iter(it, malloced); | |
576 | } | |
577 | done: | |
578 | block_iter_close(&next.bi); | |
579 | table_iter_close(&index_iter); | |
66c0daba HWN |
580 | reftable_record_release(&want_index); |
581 | reftable_record_release(&index_result); | |
46bc0e73 HWN |
582 | return err; |
583 | } | |
584 | ||
585 | static int reader_seek_internal(struct reftable_reader *r, | |
586 | struct reftable_iterator *it, | |
587 | struct reftable_record *rec) | |
588 | { | |
589 | struct reftable_reader_offsets *offs = | |
590 | reader_offsets_for(r, reftable_record_type(rec)); | |
591 | uint64_t idx = offs->index_offset; | |
592 | struct table_iter ti = TABLE_ITER_INIT; | |
593 | int err = 0; | |
594 | if (idx > 0) | |
595 | return reader_seek_indexed(r, it, rec); | |
596 | ||
597 | err = reader_start(r, &ti, reftable_record_type(rec), 0); | |
598 | if (err < 0) | |
599 | return err; | |
21a40847 | 600 | err = reader_seek_linear(&ti, rec); |
46bc0e73 HWN |
601 | if (err < 0) |
602 | return err; | |
603 | else { | |
604 | struct table_iter *p = | |
605 | reftable_malloc(sizeof(struct table_iter)); | |
606 | *p = ti; | |
607 | iterator_from_table_iter(it, p); | |
608 | } | |
609 | ||
610 | return 0; | |
611 | } | |
612 | ||
613 | static int reader_seek(struct reftable_reader *r, struct reftable_iterator *it, | |
614 | struct reftable_record *rec) | |
615 | { | |
616 | uint8_t typ = reftable_record_type(rec); | |
617 | ||
618 | struct reftable_reader_offsets *offs = reader_offsets_for(r, typ); | |
619 | if (!offs->is_present) { | |
620 | iterator_set_empty(it); | |
621 | return 0; | |
622 | } | |
623 | ||
624 | return reader_seek_internal(r, it, rec); | |
625 | } | |
626 | ||
627 | int reftable_reader_seek_ref(struct reftable_reader *r, | |
628 | struct reftable_iterator *it, const char *name) | |
629 | { | |
66c0daba HWN |
630 | struct reftable_record rec = { |
631 | .type = BLOCK_TYPE_REF, | |
632 | .u.ref = { | |
633 | .refname = (char *)name, | |
634 | }, | |
46bc0e73 | 635 | }; |
46bc0e73 HWN |
636 | return reader_seek(r, it, &rec); |
637 | } | |
638 | ||
639 | int reftable_reader_seek_log_at(struct reftable_reader *r, | |
640 | struct reftable_iterator *it, const char *name, | |
641 | uint64_t update_index) | |
642 | { | |
66c0daba HWN |
643 | struct reftable_record rec = { .type = BLOCK_TYPE_LOG, |
644 | .u.log = { | |
645 | .refname = (char *)name, | |
646 | .update_index = update_index, | |
647 | } }; | |
46bc0e73 HWN |
648 | return reader_seek(r, it, &rec); |
649 | } | |
650 | ||
651 | int reftable_reader_seek_log(struct reftable_reader *r, | |
652 | struct reftable_iterator *it, const char *name) | |
653 | { | |
654 | uint64_t max = ~((uint64_t)0); | |
655 | return reftable_reader_seek_log_at(r, it, name, max); | |
656 | } | |
657 | ||
658 | void reader_close(struct reftable_reader *r) | |
659 | { | |
660 | block_source_close(&r->source); | |
661 | FREE_AND_NULL(r->name); | |
662 | } | |
663 | ||
664 | int reftable_new_reader(struct reftable_reader **p, | |
665 | struct reftable_block_source *src, char const *name) | |
666 | { | |
b4ff12c8 | 667 | struct reftable_reader *rd = reftable_calloc(1, sizeof(*rd)); |
46bc0e73 HWN |
668 | int err = init_reader(rd, src, name); |
669 | if (err == 0) { | |
670 | *p = rd; | |
671 | } else { | |
672 | block_source_close(src); | |
673 | reftable_free(rd); | |
674 | } | |
675 | return err; | |
676 | } | |
677 | ||
678 | void reftable_reader_free(struct reftable_reader *r) | |
679 | { | |
33e92243 HWN |
680 | if (!r) |
681 | return; | |
46bc0e73 HWN |
682 | reader_close(r); |
683 | reftable_free(r); | |
684 | } | |
685 | ||
686 | static int reftable_reader_refs_for_indexed(struct reftable_reader *r, | |
687 | struct reftable_iterator *it, | |
688 | uint8_t *oid) | |
689 | { | |
66c0daba HWN |
690 | struct reftable_record want = { |
691 | .type = BLOCK_TYPE_OBJ, | |
692 | .u.obj = { | |
693 | .hash_prefix = oid, | |
694 | .hash_prefix_len = r->object_id_len, | |
695 | }, | |
46bc0e73 | 696 | }; |
46bc0e73 | 697 | struct reftable_iterator oit = { NULL }; |
66c0daba HWN |
698 | struct reftable_record got = { |
699 | .type = BLOCK_TYPE_OBJ, | |
700 | .u.obj = { 0 }, | |
701 | }; | |
46bc0e73 HWN |
702 | int err = 0; |
703 | struct indexed_table_ref_iter *itr = NULL; | |
704 | ||
705 | /* Look through the reverse index. */ | |
66c0daba | 706 | err = reader_seek(r, &oit, &want); |
46bc0e73 HWN |
707 | if (err != 0) |
708 | goto done; | |
709 | ||
710 | /* read out the reftable_obj_record */ | |
66c0daba | 711 | err = iterator_next(&oit, &got); |
46bc0e73 HWN |
712 | if (err < 0) |
713 | goto done; | |
714 | ||
66c0daba HWN |
715 | if (err > 0 || memcmp(want.u.obj.hash_prefix, got.u.obj.hash_prefix, |
716 | r->object_id_len)) { | |
46bc0e73 HWN |
717 | /* didn't find it; return empty iterator */ |
718 | iterator_set_empty(it); | |
719 | err = 0; | |
720 | goto done; | |
721 | } | |
722 | ||
723 | err = new_indexed_table_ref_iter(&itr, r, oid, hash_size(r->hash_id), | |
66c0daba HWN |
724 | got.u.obj.offsets, |
725 | got.u.obj.offset_len); | |
46bc0e73 HWN |
726 | if (err < 0) |
727 | goto done; | |
66c0daba | 728 | got.u.obj.offsets = NULL; |
46bc0e73 HWN |
729 | iterator_from_indexed_table_ref_iter(it, itr); |
730 | ||
731 | done: | |
732 | reftable_iterator_destroy(&oit); | |
66c0daba | 733 | reftable_record_release(&got); |
46bc0e73 HWN |
734 | return err; |
735 | } | |
736 | ||
737 | static int reftable_reader_refs_for_unindexed(struct reftable_reader *r, | |
738 | struct reftable_iterator *it, | |
739 | uint8_t *oid) | |
740 | { | |
741 | struct table_iter ti_empty = TABLE_ITER_INIT; | |
b4ff12c8 | 742 | struct table_iter *ti = reftable_calloc(1, sizeof(*ti)); |
46bc0e73 HWN |
743 | struct filtering_ref_iterator *filter = NULL; |
744 | struct filtering_ref_iterator empty = FILTERING_REF_ITERATOR_INIT; | |
745 | int oid_len = hash_size(r->hash_id); | |
746 | int err; | |
747 | ||
748 | *ti = ti_empty; | |
749 | err = reader_start(r, ti, BLOCK_TYPE_REF, 0); | |
750 | if (err < 0) { | |
751 | reftable_free(ti); | |
752 | return err; | |
753 | } | |
754 | ||
755 | filter = reftable_malloc(sizeof(struct filtering_ref_iterator)); | |
756 | *filter = empty; | |
757 | ||
758 | strbuf_add(&filter->oid, oid, oid_len); | |
759 | reftable_table_from_reader(&filter->tab, r); | |
760 | filter->double_check = 0; | |
761 | iterator_from_table_iter(&filter->it, ti); | |
762 | ||
763 | iterator_from_filtering_ref_iterator(it, filter); | |
764 | return 0; | |
765 | } | |
766 | ||
767 | int reftable_reader_refs_for(struct reftable_reader *r, | |
768 | struct reftable_iterator *it, uint8_t *oid) | |
769 | { | |
770 | if (r->obj_offsets.is_present) | |
771 | return reftable_reader_refs_for_indexed(r, it, oid); | |
772 | return reftable_reader_refs_for_unindexed(r, it, oid); | |
773 | } | |
774 | ||
775 | uint64_t reftable_reader_max_update_index(struct reftable_reader *r) | |
776 | { | |
777 | return r->max_update_index; | |
778 | } | |
779 | ||
780 | uint64_t reftable_reader_min_update_index(struct reftable_reader *r) | |
781 | { | |
782 | return r->min_update_index; | |
783 | } | |
784 | ||
785 | /* generic table interface. */ | |
786 | ||
787 | static int reftable_reader_seek_void(void *tab, struct reftable_iterator *it, | |
788 | struct reftable_record *rec) | |
789 | { | |
790 | return reader_seek(tab, it, rec); | |
791 | } | |
792 | ||
793 | static uint32_t reftable_reader_hash_id_void(void *tab) | |
794 | { | |
795 | return reftable_reader_hash_id(tab); | |
796 | } | |
797 | ||
798 | static uint64_t reftable_reader_min_update_index_void(void *tab) | |
799 | { | |
800 | return reftable_reader_min_update_index(tab); | |
801 | } | |
802 | ||
803 | static uint64_t reftable_reader_max_update_index_void(void *tab) | |
804 | { | |
805 | return reftable_reader_max_update_index(tab); | |
806 | } | |
807 | ||
808 | static struct reftable_table_vtable reader_vtable = { | |
809 | .seek_record = reftable_reader_seek_void, | |
810 | .hash_id = reftable_reader_hash_id_void, | |
811 | .min_update_index = reftable_reader_min_update_index_void, | |
812 | .max_update_index = reftable_reader_max_update_index_void, | |
813 | }; | |
814 | ||
815 | void reftable_table_from_reader(struct reftable_table *tab, | |
816 | struct reftable_reader *reader) | |
817 | { | |
818 | assert(!tab->ops); | |
819 | tab->ops = &reader_vtable; | |
820 | tab->table_arg = reader; | |
821 | } | |
822 | ||
823 | ||
824 | int reftable_reader_print_file(const char *tablename) | |
825 | { | |
826 | struct reftable_block_source src = { NULL }; | |
827 | int err = reftable_block_source_from_file(&src, tablename); | |
828 | struct reftable_reader *r = NULL; | |
829 | struct reftable_table tab = { NULL }; | |
830 | if (err < 0) | |
831 | goto done; | |
832 | ||
833 | err = reftable_new_reader(&r, &src, tablename); | |
834 | if (err < 0) | |
835 | goto done; | |
836 | ||
837 | reftable_table_from_reader(&tab, r); | |
838 | err = reftable_table_print(&tab); | |
839 | done: | |
840 | reftable_reader_free(r); | |
841 | return err; | |
842 | } |