reftable/reader.h

   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 READER_H
  10 #define READER_H
  11
  12 #include "block.h"
  13 #include "record.h"
  14 #include "reftable-iterator.h"
  15 #include "reftable-reader.h"
  16
  17 uint64_t block_source_size(struct reftable_block_source *source);
  18
  19 int block_source_read_block(struct reftable_block_source *source,
  20                             struct reftable_block *dest, uint64_t off,
  21                             uint32_t size);
  22 void block_source_close(struct reftable_block_source *source);
  23
  24 /* metadata for a block type */
  25 struct reftable_reader_offsets {
  26         int is_present;
  27         uint64_t offset;
  28         uint64_t index_offset;
  29 };
  30
  31 /* The state for reading a reftable file. */
  32 struct reftable_reader {
  33         /* for convenience, associate a name with the instance. */
  34         char *name;
  35         struct reftable_block_source source;
  36
  37         /* Size of the file, excluding the footer. */
  38         uint64_t size;
  39
  40         /* 'sha1' for SHA1, 's256' for SHA-256 */
  41         uint32_t hash_id;
  42
  43         uint32_t block_size;
  44         uint64_t min_update_index;
  45         uint64_t max_update_index;
  46         /* Length of the OID keys in the 'o' section */
  47         int object_id_len;
  48         int version;
  49
  50         struct reftable_reader_offsets ref_offsets;
  51         struct reftable_reader_offsets obj_offsets;
  52         struct reftable_reader_offsets log_offsets;
  53
  54         uint64_t refcount;
  55 };
  56
  57 const char *reader_name(struct reftable_reader *r);
  58
  59 int reader_init_iter(struct reftable_reader *r,
  60                      struct reftable_iterator *it,
  61                      uint8_t typ);
  62
  63 /* initialize a block reader to read from `r` */
  64 int reader_init_block_reader(struct reftable_reader *r, struct block_reader *br,
  65                              uint64_t next_off, uint8_t want_typ);
  66
  67 #endif