lsup_lua/src/lua_store.c

#include "lua_lsup.h"


static int l_store_new (lua_State *L)
{
    const LSUP_StoreType store_type = luaL_checkinteger (L, 1);
    const char *id = luaL_optstring (L, 2, NULL);
    const bool clear = lua_toboolean (L, 3);

    LSUP_Store **store_p = lua_newuserdatauv (L, sizeof (*store_p), 1);
    luaL_getmetatable (L, "LSUP.Store");
    lua_setmetatable (L, -2);

    const LSUP_StoreInt *sif = LSUP_store_int (store_type);
    if (UNLIKELY (!sif)) return luaL_error (
            L, "No interface defined for store type: %d.", store_type);

    if (clear) LOG_DEBUG("Clearing old store.");
    *store_p = LSUP_store_new (store_type, id, 0);
    if (!*store_p) return luaL_error (L, "Error creating back end store.");

    // Set up the store if a function for that is defined.
    if (sif->setup_fn && sif->setup_fn (id, clear) < LSUP_OK)
        return luaL_error (L, "Error initializing back end store.");

    return 1;
}


static int store_gc (lua_State *L)
{
    LSUP_Store **sp = luaL_checkudata(L, 1, "LSUP.Store");

    LSUP_store_free (*sp);
    *sp = NULL;

    return 0;
}


// TODO add transaction handling.


static const luaL_Reg store_lib_fn [] = {
    {"new", l_store_new},
    {NULL}
};


static const LEnumConst store_enums[] = {
    {"HTABLE", LSUP_STORE_HTABLE},
    {"MDB", LSUP_STORE_MDB},

    {NULL, 0}
};


int luaopen_lsup_store (lua_State *L)
{
    LSUP_init();  // This is idempotent: no problem calling it multiple times.
    luaL_newmetatable (L, "LSUP.Store");
    lua_pushvalue (L, -1);
    lua_setfield (L, -2, "__index");
    lua_pushcfunction (L, store_gc);
    lua_setfield (L, -2, "__gc");

    luaL_newlib (L, store_lib_fn);
    push_int_const (L, store_enums);

    return 1;
}