picrin/extlib/benz/weak.c

112 lines
2.3 KiB
C

/**
* See Copyright Notice in picrin.h
*/
#include "picrin.h"
#include "picrin/private/object.h"
KHASH_DEFINE(weak, struct object *, pic_value, kh_ptr_hash_func, kh_ptr_hash_equal)
pic_value
pic_make_weak(pic_state *pic)
{
struct weak *weak;
weak = (struct weak *)pic_obj_alloc(pic, sizeof(struct weak), PIC_TYPE_WEAK);
weak->prev = NULL;
kh_init(weak, &weak->hash);
return pic_obj_value(weak);
}
pic_value
pic_weak_ref(pic_state *pic, pic_value weak, pic_value key)
{
khash_t(weak) *h = &pic_weak_ptr(pic, weak)->hash;
int it;
it = kh_get(weak, h, pic_obj_ptr(key));
if (it == kh_end(h)) {
pic_errorf(pic, "element not found for a key: ~s", key);
}
return kh_val(h, it);
}
void
pic_weak_set(pic_state *pic, pic_value weak, pic_value key, pic_value val)
{
khash_t(weak) *h = &pic_weak_ptr(pic, weak)->hash;
int ret;
int it;
it = kh_put(weak, h, pic_obj_ptr(key), &ret);
kh_val(h, it) = val;
}
bool
pic_weak_has(pic_state *pic, pic_value weak, pic_value key)
{
khash_t(weak) *h = &pic_weak_ptr(pic, weak)->hash;
return kh_get(weak, h, pic_obj_ptr(key)) != kh_end(h);
}
void
pic_weak_del(pic_state *pic, pic_value weak, pic_value key)
{
khash_t(weak) *h = &pic_weak_ptr(pic, weak)->hash;
int it;
it = kh_get(weak, h, pic_obj_ptr(key));
if (it == kh_end(h)) {
pic_errorf(pic, "no slot named ~s found in ephemeron", key);
}
kh_del(weak, h, it);
}
static pic_value
weak_call(pic_state *pic)
{
pic_value key, val, weak;
int n;
n = pic_get_args(pic, "o|o", &key, &val);
if (! pic_obj_p(pic, key)) {
pic_errorf(pic, "attempted to set a non-object key '~s' in an ephemeron", key);
}
weak = pic_closure_ref(pic, 0);
if (n == 1) {
if (! pic_weak_has(pic, weak, key)) {
return pic_false_value(pic);
}
return pic_cons(pic, key, pic_weak_ref(pic, weak, key));
} else {
if (pic_undef_p(pic, val)) {
if (pic_weak_has(pic, weak, key)) {
pic_weak_del(pic, weak, key);
}
} else {
pic_weak_set(pic, weak, key, val);
}
return pic_undef_value(pic);
}
}
static pic_value
pic_weak_make_ephemeron(pic_state *pic)
{
pic_get_args(pic, "");
return pic_lambda(pic, weak_call, 1, pic_make_weak(pic));
}
void
pic_init_weak(pic_state *pic)
{
pic_defun(pic, "make-ephemeron", pic_weak_make_ephemeron);
}