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/*
* 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_BLOCKSOURCE_H
#define REFTABLE_BLOCKSOURCE_H
#include <stdint.h>
/*
* Generic wrapper for a seekable readable file.
*/
struct reftable_block_source {
struct reftable_block_source_vtable *ops;
void *arg;
};
/* a contiguous segment of bytes. It keeps track of its generating block_source
* so it can return itself into the pool. */
struct reftable_block_data {
uint8_t *data;
size_t len;
struct reftable_block_source source;
};
/* block_source_vtable are the operations that make up block_source */
struct reftable_block_source_vtable {
/* Returns the size of a block source. */
uint64_t (*size)(void *source);
/*
* Reads a segment from the block source. It is an error to read beyond
* the end of the block.
*/
ssize_t (*read_data)(void *source, struct reftable_block_data *dest,
uint64_t off, uint32_t size);
/* Mark the block as read; may release the data. */
void (*release_data)(void *source, struct reftable_block_data *data);
/* Release all resources associated with the block source. */
void (*close)(void *source);
};
/* opens a file on the file system as a block_source */
int reftable_block_source_from_file(struct reftable_block_source *block_src,
const char *name);
#endif
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