lander/lsm/src/_include/lsm/store_internal.h

#ifndef LSM_STORE_INTERNAL
#define LSM_STORE_INTERNAL

#include <pthread.h>
#include <stdio.h>

#include "lsm/store.h"
#include "lsm/str_internal.h"
#include "lsm/trie.h"

#define LSM_DB_FILE_NAME "lsm.db"
#define LSM_IDX_FILE_NAME "lsm.idx"

typedef struct lsm_attr {
  lsm_attr_type type;
  lsm_str *str;
} lsm_attr;

/**
 * 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_str *key;
  struct {
    uint64_t count;
    uint64_t bitmap;
    lsm_attr *items;
  } attrs;
  struct {
    uint64_t len;
    union {
      FILE *file;
      char *ptr;
    } value;
    bool on_disk;
  } data;
} 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);

typedef struct lsm_entry_wrapper {
  pthread_rwlock_t lock;
  lsm_entry *entry;
} lsm_entry_wrapper;

lsm_error lsm_entry_wrapper_init(lsm_entry_wrapper **ptr);
void lsm_entry_wrapper_free(lsm_entry_wrapper *wrapper);

struct lsm_entry_handle {
  lsm_entry_wrapper *wrapper;
  FILE *f;
  uint64_t pos;
};

lsm_error lsm_entry_handle_init(lsm_entry_handle **out);

struct lsm_store {
  lsm_trie *trie;
  lsm_str *data_path;
  FILE *db_file;
  uint64_t db_file_size;
  pthread_mutex_t db_lock;
  FILE *idx_file;
  uint64_t idx_file_size;
  pthread_mutex_t idx_lock;
};

/**
 * Read in the database and construct the in-memory trie index. This function
 * assumes the provided store is a newly initialized empty store with the
 * database files opened.
 *
 * @param store store to read
 */
lsm_error lsm_store_load_db(lsm_store *store);

#endif