lander/lsm/include/lsm/store.h

85 lines
2.0 KiB
C

#ifndef LSM_STORE
#define LSM_STORE
#include <stdbool.h>
#include <stdint.h>
#include "lsm.h"
#include "lsm/str.h"
/**
* The type of an entry attribute.
*
* Each type is represented as a single bit of an
* integer, so they can be easily combined into a bitmap.
*/
typedef enum lsm_attr_type : uint64_t {
lsm_attr_type_entry_type = 1 << 0,
lsm_attr_type_content_type = 1 << 1
} lsm_attr_type;
/**
* An entry inside an LSM store.
*
* Each entry consists of the key it's stored behind, zero or more attributes
* (metadata) and a data field. The data field can be stored on disk or
* in-memory, depending on the size.
*/
typedef struct lsm_entry lsm_entry;
/**
* Allocate and initialize a new lsm_entry object.
*
* @param ptr where to store newly allocated pointer
*/
lsm_error lsm_entry_init(lsm_entry **ptr);
/**
* Deallocate an existing lsm_entry object.
*
* @param entry object to deallocate
*/
void lsm_entry_free(lsm_entry *entry);
/**
* Checks whether the entry has an attribute with the specified type.
*
* @param entry entry to check
* @param type type of attribute to check for
*/
bool lsm_entry_attr_present(lsm_entry *entry, lsm_attr_type type);
/**
* Retrieve the contents of an attribute from an entry, if present
*
* @param out where to store pointer to attribute data
* @param entry entry to search for
* @param type type of attribute to return
*/
lsm_error lsm_entry_attr_get(lsm_str **out, lsm_entry *entry,
lsm_attr_type type);
/**
* A store consisting of LSM entries.
*
* A store manages both an in-memory data structure for quick lookup, and a
* database file for persistent storage of the contained entries.
*/
typedef struct lsm_store lsm_store;
/**
* Allocate and initialize a new lsm_store object.
*
* @param ptr where to store newly allocated pointer
*/
lsm_error lsm_store_init(lsm_store **ptr);
/**
* Dealocate an existing lsm_store object.
*
* @param store object to deallocate
*/
void lsm_store_free(lsm_store *store);
#endif