/** @internal Retrieve C layer api wrapper. */
static const knot_layer_api_t* l_ffi_layer(struct kr_module *module)
{
lua_State *L = module->lib;
lua_rawgeti(L, LUA_REGISTRYINDEX, (intptr_t)module->data);
lua_getfield(L, -1, "_layer_capi");
knot_layer_api_t *api = lua_touserdata(L, -1);
lua_pop(L, 1);
if (!api) {
/* Fabricate layer API wrapping the Lua functions */
api = malloc(sizeof(*api));
if (api) {
memset(api, 0, sizeof(*api));
/* Begin is always set, as it initializes layer baton. */
api->begin = l_ffi_layer_begin;
LAYER_REGISTER(L, api, finish);
LAYER_REGISTER(L, api, consume);
LAYER_REGISTER(L, api, produce);
LAYER_REGISTER(L, api, reset);
LAYER_REGISTER(L, api, fail);
api->data = module;
}
/* Store the api in the registry. */
lua_pushlightuserdata(L, api);
lua_setfield(L, -2, "_layer_capi");
}
lua_pop(L, 1); /* Clear module table */
return api;
}
/** @internal Create C layer api wrapper. */
static knot_layer_api_t *l_ffi_layer_create(lua_State *L, struct kr_module *module)
{
/* Fabricate layer API wrapping the Lua functions
* reserve slots after it for references to Lua callbacks. */
const size_t api_length = sizeof(knot_layer_api_t) + (SLOT_count * SLOT_size);
knot_layer_api_t *api = malloc(api_length);
if (api) {
memset(api, 0, api_length);
LAYER_REGISTER(L, api, begin);
LAYER_REGISTER(L, api, finish);
LAYER_REGISTER(L, api, consume);
LAYER_REGISTER(L, api, produce);
LAYER_REGISTER(L, api, reset);
/* Begin is always set, as it initializes layer baton. */
api->begin = l_ffi_layer_begin;
api->data = module;
}
return api;
}
