class ObjectSpace::WeakMap

An ObjectSpace::WeakMap object holds references to any objects, but those objects can get garbage collected.

This class is mostly used internally by WeakRef, please use lib/weakref.rb for the public interface.

Public Instance Methods

[](p1) click to toggle source

Retrieves a weakly referenced object with the given key

static VALUE
wmap_aref(VALUE self, VALUE wmap)
{
    st_data_t data;
    VALUE obj;
    struct weakmap *w;
    rb_objspace_t *objspace = &rb_objspace;

    TypedData_Get_Struct(self, struct weakmap, &weakmap_type, w);
    if (!st_lookup(w->wmap2obj, (st_data_t)wmap, &data)) return Qnil;
    obj = (VALUE)data;
    if (!is_id_value(objspace, obj)) return Qnil;
    if (!is_live_object(objspace, obj)) return Qnil;
    return obj;
}

[]=(p1, p2) click to toggle source

Creates a weak reference from the given key to the given value

static VALUE
wmap_aset(VALUE self, VALUE wmap, VALUE orig)
{
    st_data_t data;
    VALUE rids;
    struct weakmap *w;

    TypedData_Get_Struct(self, struct weakmap, &weakmap_type, w);
    rb_define_final(orig, w->final);
    rb_define_final(wmap, w->final);
    if (st_lookup(w->obj2wmap, (st_data_t)orig, &data)) {
        rids = (VALUE)data;
    }
    else {
        rids = rb_ary_tmp_new(1);
        st_insert(w->obj2wmap, (st_data_t)orig, (st_data_t)rids);
    }
    rb_ary_push(rids, wmap);
    st_insert(w->wmap2obj, (st_data_t)wmap, (st_data_t)orig);
    return nonspecial_obj_id(orig);
}

Private Instance Methods

finalize(p1) click to toggle source

static VALUE
wmap_finalize(VALUE self, VALUE objid)
{
    st_data_t orig, wmap, data;
    VALUE obj, rids;
    long i;
    struct weakmap *w;

    TypedData_Get_Struct(self, struct weakmap, &weakmap_type, w);
    /* Get reference from object id. */
    obj = obj_id_to_ref(objid);

    /* obj is original referenced object and/or weak reference. */
    orig = (st_data_t)obj;
    if (st_delete(w->obj2wmap, &orig, &data)) {
        rids = (VALUE)data;
        for (i = 0; i < RARRAY_LEN(rids); ++i) {
            wmap = (st_data_t)RARRAY_PTR(rids)[i];
            st_delete(w->wmap2obj, &wmap, NULL);
        }
    }

    wmap = (st_data_t)obj;
    if (st_delete(w->wmap2obj, &wmap, &orig)) {
        wmap = (st_data_t)obj;
        st_update(w->obj2wmap, orig, wmap_final_func, wmap);
    }
    return self;
}