git/reftable/reader.h
Han-Wen Nienhuys 46bc0e731a reftable: read reftable files
This supports reading a single reftable file.

The commit introduces an abstract iterator type, which captures the usecases
both of reading individual refs, and iterating over a segment of the ref
namespace.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-08 10:45:48 -07:00

65 lines
1.7 KiB
C

/*
Copyright 2020 Google LLC
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file or at
https://developers.google.com/open-source/licenses/bsd
*/
#ifndef READER_H
#define READER_H
#include "block.h"
#include "record.h"
#include "reftable-iterator.h"
#include "reftable-reader.h"
uint64_t block_source_size(struct reftable_block_source *source);
int block_source_read_block(struct reftable_block_source *source,
struct reftable_block *dest, uint64_t off,
uint32_t size);
void block_source_close(struct reftable_block_source *source);
/* metadata for a block type */
struct reftable_reader_offsets {
int is_present;
uint64_t offset;
uint64_t index_offset;
};
/* The state for reading a reftable file. */
struct reftable_reader {
/* for convience, associate a name with the instance. */
char *name;
struct reftable_block_source source;
/* Size of the file, excluding the footer. */
uint64_t size;
/* 'sha1' for SHA1, 's256' for SHA-256 */
uint32_t hash_id;
uint32_t block_size;
uint64_t min_update_index;
uint64_t max_update_index;
/* Length of the OID keys in the 'o' section */
int object_id_len;
int version;
struct reftable_reader_offsets ref_offsets;
struct reftable_reader_offsets obj_offsets;
struct reftable_reader_offsets log_offsets;
};
int init_reader(struct reftable_reader *r, struct reftable_block_source *source,
const char *name);
void reader_close(struct reftable_reader *r);
const char *reader_name(struct reftable_reader *r);
/* initialize a block reader to read from `r` */
int reader_init_block_reader(struct reftable_reader *r, struct block_reader *br,
uint64_t next_off, uint8_t want_typ);
#endif