SQLite

** This is an opaque object.  The public interface sees pointers to this
** object, but not the internals.  So the internal composition of this
** object is free to change from one release to the next without breaking
** compatibility.
*/
struct sqlite3_kv {
  sqlite3 *db;            /* The database holding the table to be accessed */

  u32 iRoot;              /* Root page of the table */
  int iGen;               /* Schema generation number */
  int iCookie;            /* Schema cookie number from the database file */
  Schema *pSchema;        /* Schema holding the table */
  sqlite3_int64 iRowid;   /* Current rowid */
};

/*
** Create a new sqlite3_kv object open on zDb.zTable and return
** a pointer to that object.
*/

  }
  *ppKvOut = pKv = sqlite3_malloc(sizeof(*pKv));
  if( pKv==0 ){
    rc = SQLITE_NOMEM;
    goto kv_open_done;
  }
  pKv->db = db;
  pKv->iGen = pTab->pSchema->iGeneration;
  pKv->iCookie = pTab->pSchema->schema_cookie;
  pKv->pSchema = pTab->pSchema;
  pKv->iRoot = pTab->tnum;
  rc = SQLITE_OK;

kv_open_done:
  sqlite3BtreeLeaveAll(db);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

/*
** Free the key/value accessor at pKv
*/
int sqlite3_kv_close(sqlite3_kv *pKv){
  sqlite3_free(pKv);
  return SQLITE_OK;
}

int sqlite3_kv_seek(sqlite3_kv *pKv, sqlite3_int64 rowid){
  return SQLITE_MISUSE;
}
int sqlite3_kv_reset(sqlite3_kv *pKv){
  return SQLITE_MISUSE;
}
int sqlite3_kv_bytes(sqlite3_kv *pKv){
  return -1;
}
int sqlite3_kv_read(sqlite3_kv *pKv, void *pBuf, int amt, int offset){
  return SQLITE_MISUSE;
}
int sqlite3_kv_insert(sqlite3_kv *pKv, sqlite3_int64 rid, int sz, void *pBuf){
  return SQLITE_MISUSE;
}

#endif /* #ifndef SQLITE_OMIT_KEYVALU_ACCESSOR */

** SQLITE_OK on success or an error code if it is unable to complete
** the operation.  If no record exists with rowid I, then sqlite3_kv_seek(P,I)
** attempts to position itself at another nearby record and returns
** either SQLITE_KV_BEFORE or SQLITE_KV_AFTER depending on whether the
** record the accessor is left pointing to is less than or greater than I,
** respectively.  If the table is empty, sqlite3_kv_seek(P,I) returns
** SQLITE_EMPTY.
**
** A successful sqlite3_kv_seek(P,I) call leave the key/value accessor
** P holding a read transaction open on the database.  Use sqlite3_kv_reset(P)
** or sqlite3_kv_close(P) to release this transaction.
*/
int sqlite3_kv_seek(sqlite3_kv*, sqlite3_int64 rowid);

/*
** CAPI3REF: Reset a key/value accessor object
** METHOD: sqlite3_kv
** EXPERIMENTAL
**
** The sqlite3_kv_reset(P) interface restores the key/value accessor P
** back to its original state, releasing any transactions held.
*/
int sqlite3_kv_reset(sqlite3_kv*);

/*
** CAPI3REF: Find the size of the value for a key/value pair
** METHOD: sqlite3_kv
** EXPERIMENTAL
**
** The sqlite3_kv_bytes(P) interface returns the size of the value
** in the key/value pair that the key/value accessor object P is currently