| 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 | #ifndef REFTABLE_MERGED_H |
| 10 | #define REFTABLE_MERGED_H |
| 11 | |
| 12 | #include "reftable-system.h" |
| 13 | #include "reftable-iterator.h" |
| 14 | |
| 15 | /* |
| 16 | * Merged tables |
| 17 | * |
| 18 | * A ref database kept in a sequence of table files. The merged_table presents a |
| 19 | * unified view to reading (seeking, iterating) a sequence of immutable tables. |
| 20 | * |
| 21 | * The merged tables are on purpose kept disconnected from their actual storage |
| 22 | * (eg. files on disk), because it is useful to merge tables aren't files. For |
| 23 | * example, the per-workspace and global ref namespace can be implemented as a |
| 24 | * merged table of two stacks of file-backed reftables. |
| 25 | */ |
| 26 | |
| 27 | /* A merged table is implements seeking/iterating over a stack of tables. */ |
| 28 | struct reftable_merged_table; |
| 29 | |
| 30 | struct reftable_table; |
| 31 | |
| 32 | /* |
| 33 | * reftable_merged_table_new creates a new merged table. The tables must be |
| 34 | * kept alive as long as the merged table is still in use. |
| 35 | */ |
| 36 | int reftable_merged_table_new(struct reftable_merged_table **dest, |
| 37 | struct reftable_table **tables, size_t n, |
| 38 | enum reftable_hash hash_id); |
| 39 | |
| 40 | /* Initialize a merged table iterator for reading refs. */ |
| 41 | int reftable_merged_table_init_ref_iterator(struct reftable_merged_table *mt, |
| 42 | struct reftable_iterator *it); |
| 43 | |
| 44 | /* Initialize a merged table iterator for reading logs. */ |
| 45 | int reftable_merged_table_init_log_iterator(struct reftable_merged_table *mt, |
| 46 | struct reftable_iterator *it); |
| 47 | |
| 48 | /* returns the max update_index covered by this merged table. */ |
| 49 | uint64_t |
| 50 | reftable_merged_table_max_update_index(struct reftable_merged_table *mt); |
| 51 | |
| 52 | /* returns the min update_index covered by this merged table. */ |
| 53 | uint64_t |
| 54 | reftable_merged_table_min_update_index(struct reftable_merged_table *mt); |
| 55 | |
| 56 | /* releases memory for the merged_table */ |
| 57 | void reftable_merged_table_free(struct reftable_merged_table *m); |
| 58 | |
| 59 | /* return the hash ID of the merged table. */ |
| 60 | enum reftable_hash reftable_merged_table_hash_id(struct reftable_merged_table *m); |
| 61 | |
| 62 | #endif |