c-libp2p/include/libp2p/db/datastore.h

#pragma once

#include <stdint.h>

/***
 * Interface to data storage
 */

enum DatastoreCursorOp { CURSOR_FIRST, CURSOR_NEXT, CURSOR_LAST, CURSOR_PREVIOUS };

struct DatastoreRecord {
	uint8_t *key;
	size_t key_size;
	uint8_t *value;
	size_t value_size;
	unsigned long long timestamp;
};

struct Datastore {
	char* type;
	char* path;
	char* storage_max;
	int storage_gc_watermark;
	char* gc_period;
	char* params;
	int no_sync;
	int hash_on_read;
	int bloom_filter_size;

	// function pointers for datastore operations
	int (*datastore_open)(int argc, char** argv, struct Datastore* datastore);
	int (*datastore_close)(struct Datastore* datastore);
	int (*datastore_put)(struct DatastoreRecord* record, const struct Datastore* datastore);
	int (*datastore_get)(const unsigned char* key, size_t key_size, struct DatastoreRecord** record, const struct Datastore* datastore);
	int (*datastore_cursor_open)(struct Datastore* datastore);
	int (*datastore_cursor_close)(struct Datastore* datastore);
	int (*datastore_cursor_get)(unsigned char** key, int* key_length, unsigned char** value, int* value_length, enum DatastoreCursorOp op, struct Datastore* datastore);
	// generic connection and status variables for the datastore
	void* datastore_context; // a handle to a context that holds connectivity information
};

/***
 * Initialize the structure of the datastore to default settings. Used for
 * creating a new datastore on the disk.
 * @param datastore the struct to initialize
 * @param config_root the path to the root of IPFS
 * @returns true(1) on success
 */
int libp2p_datastore_init(struct Datastore* datastore, const char* config_root);

/***
 * initialize the structure of the datastore
 * @param datastore the struct to initialize
 * @returns true(1) on success
 */
int libp2p_datastore_new(struct Datastore** datastore);


/***
 * deallocate the memory and clear resources from a datastore_init
 * @param datastore the struct to deallocate
 * @returns true(1)
 */
int libp2p_datastore_free(struct Datastore* datastore);

/***
 * Create a new DatastoreRecord struct
 * @returns a newly allocated DatastoreRecord struct
 */
struct DatastoreRecord* libp2p_datastore_record_new();

/***
 * Free resources of a DatastoreRecord
 */
int libp2p_datastore_record_free(struct DatastoreRecord* record);