You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
127 lines
3.5 KiB
127 lines
3.5 KiB
/* |
|
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 BLOCK_H |
|
#define BLOCK_H |
|
|
|
#include "basics.h" |
|
#include "record.h" |
|
#include "reftable-blocksource.h" |
|
|
|
/* |
|
* Writes reftable blocks. The block_writer is reused across blocks to minimize |
|
* allocation overhead. |
|
*/ |
|
struct block_writer { |
|
uint8_t *buf; |
|
uint32_t block_size; |
|
|
|
/* Offset of the global header. Nonzero in the first block only. */ |
|
uint32_t header_off; |
|
|
|
/* How often to restart keys. */ |
|
int restart_interval; |
|
int hash_size; |
|
|
|
/* Offset of next uint8_t to write. */ |
|
uint32_t next; |
|
uint32_t *restarts; |
|
uint32_t restart_len; |
|
uint32_t restart_cap; |
|
|
|
struct strbuf last_key; |
|
int entries; |
|
}; |
|
|
|
/* |
|
* initializes the blockwriter to write `typ` entries, using `buf` as temporary |
|
* storage. `buf` is not owned by the block_writer. */ |
|
void block_writer_init(struct block_writer *bw, uint8_t typ, uint8_t *buf, |
|
uint32_t block_size, uint32_t header_off, int hash_size); |
|
|
|
/* returns the block type (eg. 'r' for ref records. */ |
|
uint8_t block_writer_type(struct block_writer *bw); |
|
|
|
/* appends the record, or -1 if it doesn't fit. */ |
|
int block_writer_add(struct block_writer *w, struct reftable_record *rec); |
|
|
|
/* appends the key restarts, and compress the block if necessary. */ |
|
int block_writer_finish(struct block_writer *w); |
|
|
|
/* clears out internally allocated block_writer members. */ |
|
void block_writer_release(struct block_writer *bw); |
|
|
|
/* Read a block. */ |
|
struct block_reader { |
|
/* offset of the block header; nonzero for the first block in a |
|
* reftable. */ |
|
uint32_t header_off; |
|
|
|
/* the memory block */ |
|
struct reftable_block block; |
|
int hash_size; |
|
|
|
/* size of the data, excluding restart data. */ |
|
uint32_t block_len; |
|
uint8_t *restart_bytes; |
|
uint16_t restart_count; |
|
|
|
/* size of the data in the file. For log blocks, this is the compressed |
|
* size. */ |
|
uint32_t full_block_size; |
|
}; |
|
|
|
/* Iterate over entries in a block */ |
|
struct block_iter { |
|
/* offset within the block of the next entry to read. */ |
|
uint32_t next_off; |
|
struct block_reader *br; |
|
|
|
/* key for last entry we read. */ |
|
struct strbuf last_key; |
|
}; |
|
|
|
/* initializes a block reader. */ |
|
int block_reader_init(struct block_reader *br, struct reftable_block *bl, |
|
uint32_t header_off, uint32_t table_block_size, |
|
int hash_size); |
|
|
|
/* Position `it` at start of the block */ |
|
void block_reader_start(struct block_reader *br, struct block_iter *it); |
|
|
|
/* Position `it` to the `want` key in the block */ |
|
int block_reader_seek(struct block_reader *br, struct block_iter *it, |
|
struct strbuf *want); |
|
|
|
/* Returns the block type (eg. 'r' for refs) */ |
|
uint8_t block_reader_type(struct block_reader *r); |
|
|
|
/* Decodes the first key in the block */ |
|
int block_reader_first_key(struct block_reader *br, struct strbuf *key); |
|
|
|
void block_iter_copy_from(struct block_iter *dest, struct block_iter *src); |
|
|
|
/* return < 0 for error, 0 for OK, > 0 for EOF. */ |
|
int block_iter_next(struct block_iter *it, struct reftable_record *rec); |
|
|
|
/* Seek to `want` with in the block pointed to by `it` */ |
|
int block_iter_seek(struct block_iter *it, struct strbuf *want); |
|
|
|
/* deallocate memory for `it`. The block reader and its block is left intact. */ |
|
void block_iter_close(struct block_iter *it); |
|
|
|
/* size of file header, depending on format version */ |
|
int header_size(int version); |
|
|
|
/* size of file footer, depending on format version */ |
|
int footer_size(int version); |
|
|
|
/* returns a block to its source. */ |
|
void reftable_block_done(struct reftable_block *ret); |
|
|
|
#endif
|
|
|