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1ae2b8cd 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 "merged.h" | |
10 | ||
11 | #include "constants.h" | |
12 | #include "iter.h" | |
13 | #include "pq.h" | |
1ae2b8cd HWN |
14 | #include "record.h" |
15 | #include "generic.h" | |
16 | #include "reftable-merged.h" | |
17 | #include "reftable-error.h" | |
18 | #include "system.h" | |
19 | ||
bb2d6be4 PS |
20 | struct merged_subiter { |
21 | struct reftable_iterator iter; | |
22 | struct reftable_record rec; | |
23 | }; | |
24 | ||
48929d2e | 25 | struct merged_iter { |
bb2d6be4 | 26 | struct merged_subiter *subiters; |
aad8ad6f | 27 | struct merged_iter_pqueue pq; |
48929d2e PS |
28 | uint32_t hash_id; |
29 | size_t stack_len; | |
30 | uint8_t typ; | |
31 | int suppress_deletions; | |
aad8ad6f | 32 | ssize_t advance_index; |
48929d2e PS |
33 | }; |
34 | ||
1ae2b8cd HWN |
35 | static int merged_iter_init(struct merged_iter *mi) |
36 | { | |
62d3c8e8 PS |
37 | for (size_t i = 0; i < mi->stack_len; i++) { |
38 | struct pq_entry e = { | |
62d3c8e8 | 39 | .index = i, |
bb2d6be4 | 40 | .rec = &mi->subiters[i].rec, |
62d3c8e8 PS |
41 | }; |
42 | int err; | |
43 | ||
bb2d6be4 PS |
44 | reftable_record_init(&mi->subiters[i].rec, mi->typ); |
45 | err = iterator_next(&mi->subiters[i].iter, | |
46 | &mi->subiters[i].rec); | |
62d3c8e8 | 47 | if (err < 0) |
1ae2b8cd | 48 | return err; |
1ae2b8cd | 49 | if (err > 0) { |
bb2d6be4 PS |
50 | reftable_iterator_destroy(&mi->subiters[i].iter); |
51 | reftable_record_release(&mi->subiters[i].rec); | |
62d3c8e8 | 52 | continue; |
1ae2b8cd | 53 | } |
62d3c8e8 PS |
54 | |
55 | merged_iter_pqueue_add(&mi->pq, &e); | |
1ae2b8cd HWN |
56 | } |
57 | ||
58 | return 0; | |
59 | } | |
60 | ||
61 | static void merged_iter_close(void *p) | |
62 | { | |
63 | struct merged_iter *mi = p; | |
81879123 | 64 | |
1ae2b8cd | 65 | merged_iter_pqueue_release(&mi->pq); |
bb2d6be4 PS |
66 | for (size_t i = 0; i < mi->stack_len; i++) { |
67 | reftable_iterator_destroy(&mi->subiters[i].iter); | |
68 | reftable_record_release(&mi->subiters[i].rec); | |
69 | } | |
70 | reftable_free(mi->subiters); | |
1ae2b8cd HWN |
71 | } |
72 | ||
73 | static int merged_iter_advance_nonnull_subiter(struct merged_iter *mi, | |
74 | size_t idx) | |
75 | { | |
1ae2b8cd | 76 | struct pq_entry e = { |
1ae2b8cd | 77 | .index = idx, |
bb2d6be4 | 78 | .rec = &mi->subiters[idx].rec, |
1ae2b8cd | 79 | }; |
3ddef475 PS |
80 | int err; |
81 | ||
bb2d6be4 | 82 | err = iterator_next(&mi->subiters[idx].iter, &mi->subiters[idx].rec); |
1ae2b8cd HWN |
83 | if (err < 0) |
84 | return err; | |
1ae2b8cd | 85 | if (err > 0) { |
bb2d6be4 PS |
86 | reftable_iterator_destroy(&mi->subiters[idx].iter); |
87 | reftable_record_release(&mi->subiters[idx].rec); | |
1ae2b8cd HWN |
88 | return 0; |
89 | } | |
90 | ||
c18eecbe | 91 | merged_iter_pqueue_add(&mi->pq, &e); |
1ae2b8cd HWN |
92 | return 0; |
93 | } | |
94 | ||
95 | static int merged_iter_advance_subiter(struct merged_iter *mi, size_t idx) | |
96 | { | |
bb2d6be4 | 97 | if (iterator_is_null(&mi->subiters[idx].iter)) |
1ae2b8cd HWN |
98 | return 0; |
99 | return merged_iter_advance_nonnull_subiter(mi, idx); | |
100 | } | |
101 | ||
102 | static int merged_iter_next_entry(struct merged_iter *mi, | |
103 | struct reftable_record *rec) | |
104 | { | |
1ae2b8cd HWN |
105 | struct pq_entry entry = { 0 }; |
106 | int err = 0; | |
107 | ||
aad8ad6f PS |
108 | if (mi->advance_index >= 0) { |
109 | err = merged_iter_advance_subiter(mi, mi->advance_index); | |
110 | if (err < 0) | |
111 | return err; | |
112 | mi->advance_index = -1; | |
113 | } | |
114 | ||
1ae2b8cd HWN |
115 | if (merged_iter_pqueue_is_empty(mi->pq)) |
116 | return 1; | |
117 | ||
118 | entry = merged_iter_pqueue_remove(&mi->pq); | |
1ae2b8cd HWN |
119 | |
120 | /* | |
121 | One can also use reftable as datacenter-local storage, where the ref | |
122 | database is maintained in globally consistent database (eg. | |
123 | CockroachDB or Spanner). In this scenario, replication delays together | |
124 | with compaction may cause newer tables to contain older entries. In | |
125 | such a deployment, the loop below must be changed to collect all | |
126 | entries for the same key, and return new the newest one. | |
127 | */ | |
1ae2b8cd HWN |
128 | while (!merged_iter_pqueue_is_empty(mi->pq)) { |
129 | struct pq_entry top = merged_iter_pqueue_top(mi->pq); | |
a96e9a20 | 130 | int cmp; |
1ae2b8cd | 131 | |
bb2d6be4 | 132 | cmp = reftable_record_cmp(top.rec, entry.rec); |
829231dc | 133 | if (cmp > 0) |
1ae2b8cd | 134 | break; |
1ae2b8cd HWN |
135 | |
136 | merged_iter_pqueue_remove(&mi->pq); | |
137 | err = merged_iter_advance_subiter(mi, top.index); | |
829231dc | 138 | if (err < 0) |
bb2d6be4 | 139 | return err; |
1ae2b8cd HWN |
140 | } |
141 | ||
aad8ad6f | 142 | mi->advance_index = entry.index; |
bb2d6be4 PS |
143 | SWAP(*rec, *entry.rec); |
144 | return 0; | |
1ae2b8cd HWN |
145 | } |
146 | ||
147 | static int merged_iter_next(struct merged_iter *mi, struct reftable_record *rec) | |
148 | { | |
149 | while (1) { | |
150 | int err = merged_iter_next_entry(mi, rec); | |
151 | if (err == 0 && mi->suppress_deletions && | |
152 | reftable_record_is_deletion(rec)) { | |
153 | continue; | |
154 | } | |
155 | ||
156 | return err; | |
157 | } | |
158 | } | |
159 | ||
160 | static int merged_iter_next_void(void *p, struct reftable_record *rec) | |
161 | { | |
162 | struct merged_iter *mi = p; | |
aad8ad6f | 163 | if (merged_iter_pqueue_is_empty(mi->pq) && mi->advance_index < 0) |
1ae2b8cd | 164 | return 1; |
1ae2b8cd HWN |
165 | return merged_iter_next(mi, rec); |
166 | } | |
167 | ||
168 | static struct reftable_iterator_vtable merged_iter_vtable = { | |
169 | .next = &merged_iter_next_void, | |
170 | .close = &merged_iter_close, | |
171 | }; | |
172 | ||
173 | static void iterator_from_merged_iter(struct reftable_iterator *it, | |
174 | struct merged_iter *mi) | |
175 | { | |
176 | assert(!it->ops); | |
177 | it->iter_arg = mi; | |
178 | it->ops = &merged_iter_vtable; | |
179 | } | |
180 | ||
181 | int reftable_new_merged_table(struct reftable_merged_table **dest, | |
81879123 | 182 | struct reftable_table *stack, size_t n, |
1ae2b8cd HWN |
183 | uint32_t hash_id) |
184 | { | |
185 | struct reftable_merged_table *m = NULL; | |
186 | uint64_t last_max = 0; | |
187 | uint64_t first_min = 0; | |
81879123 PS |
188 | |
189 | for (size_t i = 0; i < n; i++) { | |
1ae2b8cd HWN |
190 | uint64_t min = reftable_table_min_update_index(&stack[i]); |
191 | uint64_t max = reftable_table_max_update_index(&stack[i]); | |
192 | ||
193 | if (reftable_table_hash_id(&stack[i]) != hash_id) { | |
194 | return REFTABLE_FORMAT_ERROR; | |
195 | } | |
196 | if (i == 0 || min < first_min) { | |
197 | first_min = min; | |
198 | } | |
199 | if (i == 0 || max > last_max) { | |
200 | last_max = max; | |
201 | } | |
202 | } | |
203 | ||
b4ff12c8 | 204 | REFTABLE_CALLOC_ARRAY(m, 1); |
1ae2b8cd HWN |
205 | m->stack = stack; |
206 | m->stack_len = n; | |
207 | m->min = first_min; | |
208 | m->max = last_max; | |
209 | m->hash_id = hash_id; | |
210 | *dest = m; | |
211 | return 0; | |
212 | } | |
213 | ||
214 | /* clears the list of subtable, without affecting the readers themselves. */ | |
215 | void merged_table_release(struct reftable_merged_table *mt) | |
216 | { | |
217 | FREE_AND_NULL(mt->stack); | |
218 | mt->stack_len = 0; | |
219 | } | |
220 | ||
221 | void reftable_merged_table_free(struct reftable_merged_table *mt) | |
222 | { | |
223 | if (!mt) { | |
224 | return; | |
225 | } | |
226 | merged_table_release(mt); | |
227 | reftable_free(mt); | |
228 | } | |
229 | ||
230 | uint64_t | |
231 | reftable_merged_table_max_update_index(struct reftable_merged_table *mt) | |
232 | { | |
233 | return mt->max; | |
234 | } | |
235 | ||
236 | uint64_t | |
237 | reftable_merged_table_min_update_index(struct reftable_merged_table *mt) | |
238 | { | |
239 | return mt->min; | |
240 | } | |
241 | ||
242 | static int reftable_table_seek_record(struct reftable_table *tab, | |
243 | struct reftable_iterator *it, | |
244 | struct reftable_record *rec) | |
245 | { | |
246 | return tab->ops->seek_record(tab->table_arg, it, rec); | |
247 | } | |
248 | ||
249 | static int merged_table_seek_record(struct reftable_merged_table *mt, | |
250 | struct reftable_iterator *it, | |
251 | struct reftable_record *rec) | |
252 | { | |
1ae2b8cd | 253 | struct merged_iter merged = { |
1ae2b8cd HWN |
254 | .typ = reftable_record_type(rec), |
255 | .hash_id = mt->hash_id, | |
256 | .suppress_deletions = mt->suppress_deletions, | |
aad8ad6f | 257 | .advance_index = -1, |
1ae2b8cd | 258 | }; |
59f302ca PS |
259 | struct merged_iter *p; |
260 | int err; | |
261 | ||
bb2d6be4 | 262 | REFTABLE_CALLOC_ARRAY(merged.subiters, mt->stack_len); |
59f302ca PS |
263 | for (size_t i = 0; i < mt->stack_len; i++) { |
264 | err = reftable_table_seek_record(&mt->stack[i], | |
bb2d6be4 | 265 | &merged.subiters[merged.stack_len].iter, rec); |
59f302ca PS |
266 | if (err < 0) |
267 | goto out; | |
268 | if (!err) | |
269 | merged.stack_len++; | |
1ae2b8cd HWN |
270 | } |
271 | ||
1ae2b8cd | 272 | err = merged_iter_init(&merged); |
59f302ca PS |
273 | if (err < 0) |
274 | goto out; | |
275 | ||
276 | p = reftable_malloc(sizeof(struct merged_iter)); | |
277 | *p = merged; | |
278 | iterator_from_merged_iter(it, p); | |
279 | ||
280 | out: | |
281 | if (err < 0) | |
1ae2b8cd | 282 | merged_iter_close(&merged); |
59f302ca | 283 | return err; |
1ae2b8cd HWN |
284 | } |
285 | ||
286 | int reftable_merged_table_seek_ref(struct reftable_merged_table *mt, | |
287 | struct reftable_iterator *it, | |
288 | const char *name) | |
289 | { | |
66c0daba HWN |
290 | struct reftable_record rec = { |
291 | .type = BLOCK_TYPE_REF, | |
292 | .u.ref = { | |
293 | .refname = (char *)name, | |
294 | }, | |
1ae2b8cd | 295 | }; |
1ae2b8cd HWN |
296 | return merged_table_seek_record(mt, it, &rec); |
297 | } | |
298 | ||
299 | int reftable_merged_table_seek_log_at(struct reftable_merged_table *mt, | |
300 | struct reftable_iterator *it, | |
301 | const char *name, uint64_t update_index) | |
302 | { | |
66c0daba HWN |
303 | struct reftable_record rec = { .type = BLOCK_TYPE_LOG, |
304 | .u.log = { | |
305 | .refname = (char *)name, | |
306 | .update_index = update_index, | |
307 | } }; | |
1ae2b8cd HWN |
308 | return merged_table_seek_record(mt, it, &rec); |
309 | } | |
310 | ||
311 | int reftable_merged_table_seek_log(struct reftable_merged_table *mt, | |
312 | struct reftable_iterator *it, | |
313 | const char *name) | |
314 | { | |
315 | uint64_t max = ~((uint64_t)0); | |
316 | return reftable_merged_table_seek_log_at(mt, it, name, max); | |
317 | } | |
318 | ||
319 | uint32_t reftable_merged_table_hash_id(struct reftable_merged_table *mt) | |
320 | { | |
321 | return mt->hash_id; | |
322 | } | |
323 | ||
324 | static int reftable_merged_table_seek_void(void *tab, | |
325 | struct reftable_iterator *it, | |
326 | struct reftable_record *rec) | |
327 | { | |
328 | return merged_table_seek_record(tab, it, rec); | |
329 | } | |
330 | ||
331 | static uint32_t reftable_merged_table_hash_id_void(void *tab) | |
332 | { | |
333 | return reftable_merged_table_hash_id(tab); | |
334 | } | |
335 | ||
336 | static uint64_t reftable_merged_table_min_update_index_void(void *tab) | |
337 | { | |
338 | return reftable_merged_table_min_update_index(tab); | |
339 | } | |
340 | ||
341 | static uint64_t reftable_merged_table_max_update_index_void(void *tab) | |
342 | { | |
343 | return reftable_merged_table_max_update_index(tab); | |
344 | } | |
345 | ||
346 | static struct reftable_table_vtable merged_table_vtable = { | |
347 | .seek_record = reftable_merged_table_seek_void, | |
348 | .hash_id = reftable_merged_table_hash_id_void, | |
349 | .min_update_index = reftable_merged_table_min_update_index_void, | |
350 | .max_update_index = reftable_merged_table_max_update_index_void, | |
351 | }; | |
352 | ||
353 | void reftable_table_from_merged_table(struct reftable_table *tab, | |
354 | struct reftable_merged_table *merged) | |
355 | { | |
356 | assert(!tab->ops); | |
357 | tab->ops = &merged_table_vtable; | |
358 | tab->table_arg = merged; | |
359 | } |