static void
fetch_parent(lua_State *L, int index) {
lua_getuservalue(L, 1);
lua_rawgeti(L, -1, index+1);
// A child may not exist, but the name is valid. (empty dummy child)
if (!lua_isnil(L, -1)) {
ref_parent(L, lua_gettop(L), 1);
}
}
static int
lmount(lua_State *L) {
struct sprite *s = self(L);
const char * name = luaL_checkstring(L,2);
int index = sprite_child(s, name);
if (index < 0) {
return luaL_error(L, "No child name %s", name);
}
lua_getuservalue(L, 1);
struct sprite * child = (struct sprite *)lua_touserdata(L, 3);
lua_rawgeti(L, -1, index+1);
if (lua_isnil(L, -1)) {
lua_pop(L, 1);
} else {
struct sprite * c = lua_touserdata(L, -1);
if (c == child) {
// mount not change
return 0;
}
if (!c->multimount) {
// try to remove parent ref
lua_getuservalue(L, -1);
if (lua_istable(L, -1)) {
lua_pushnil(L);
lua_rawseti(L, -2, 0);
}
lua_pop(L, 2);
} else {
lua_pop(L, 1);
}
}
if (child == NULL) {
sprite_mount(s, index, NULL);
lua_pushnil(L);
lua_rawseti(L, -2, index+1);
} else {
if (child->parent) {
unlink_parent(L, child, 3);
}
sprite_mount(s, index, child);
lua_pushvalue(L, 3);
lua_rawseti(L, -2, index+1);
if (!child->multimount) { // multimount has no parent
// set child's new parent
ref_parent(L, 3, 1);
}
}
return 0;
}
static struct sprite *
lookup(lua_State *L, struct sprite * spr) {
int i;
struct sprite * root = (struct sprite *)lua_touserdata(L, -1);
lua_getuservalue(L,-1);
for (i=0;sprite_component(root, i)>=0;i++) {
struct sprite * child = root->data.children[i];
if (child) {
lua_rawgeti(L, -1, i+1); // parent, reftable, child
if (child == spr) {
int child_index = lua_gettop(L);
int parent_index = child_index - 2;
ref_parent(L, child_index, parent_index);
lua_replace(L,-2); // parent
return child;
} else {
lua_pop(L,1);
}
}
}
lua_pop(L,1);
return NULL;
}