git/reftable/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

102 lines
3.1 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 REFTABLE_READER_H
#define REFTABLE_READER_H
#include "reftable-iterator.h"
#include "reftable-blocksource.h"
/*
* Reading single tables
*
* The follow routines are for reading single files. For an
* application-level interface, skip ahead to struct
* reftable_merged_table and struct reftable_stack.
*/
/* The reader struct is a handle to an open reftable file. */
struct reftable_reader;
/* Generic table. */
struct reftable_table;
/* reftable_new_reader opens a reftable for reading. If successful,
* returns 0 code and sets pp. The name is used for creating a
* stack. Typically, it is the basename of the file. The block source
* `src` is owned by the reader, and is closed on calling
* reftable_reader_destroy(). On error, the block source `src` is
* closed as well.
*/
int reftable_new_reader(struct reftable_reader **pp,
struct reftable_block_source *src, const char *name);
/* reftable_reader_seek_ref returns an iterator where 'name' would be inserted
in the table. To seek to the start of the table, use name = "".
example:
struct reftable_reader *r = NULL;
int err = reftable_new_reader(&r, &src, "filename");
if (err < 0) { ... }
struct reftable_iterator it = {0};
err = reftable_reader_seek_ref(r, &it, "refs/heads/master");
if (err < 0) { ... }
struct reftable_ref_record ref = {0};
while (1) {
err = reftable_iterator_next_ref(&it, &ref);
if (err > 0) {
break;
}
if (err < 0) {
..error handling..
}
..found..
}
reftable_iterator_destroy(&it);
reftable_ref_record_release(&ref);
*/
int reftable_reader_seek_ref(struct reftable_reader *r,
struct reftable_iterator *it, const char *name);
/* returns the hash ID used in this table. */
uint32_t reftable_reader_hash_id(struct reftable_reader *r);
/* seek to logs for the given name, older than update_index. To seek to the
start of the table, use name = "".
*/
int reftable_reader_seek_log_at(struct reftable_reader *r,
struct reftable_iterator *it, const char *name,
uint64_t update_index);
/* seek to newest log entry for given name. */
int reftable_reader_seek_log(struct reftable_reader *r,
struct reftable_iterator *it, const char *name);
/* closes and deallocates a reader. */
void reftable_reader_free(struct reftable_reader *);
/* return an iterator for the refs pointing to `oid`. */
int reftable_reader_refs_for(struct reftable_reader *r,
struct reftable_iterator *it, uint8_t *oid);
/* return the max_update_index for a table */
uint64_t reftable_reader_max_update_index(struct reftable_reader *r);
/* return the min_update_index for a table */
uint64_t reftable_reader_min_update_index(struct reftable_reader *r);
/* creates a generic table from a file reader. */
void reftable_table_from_reader(struct reftable_table *tab,
struct reftable_reader *reader);
/* print table onto stdout for debugging. */
int reftable_reader_print_file(const char *tablename);
#endif