Adding `GC.compact` and compacting GC support.

This commit adds the new method `GC.compact` and compacting GC support.
Please see this issue for caveats:

  https://bugs.ruby-lang.org/issues/15626

[Feature #15626]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67576 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 22 insertions, 0 deletions

diff --git a/id_table.c b/id_table.c
index 74c9e756a0..f566582479 100644
--- a/id_table.c
+++ b/id_table.c
@@ -267,6 +267,28 @@ rb_id_table_delete(struct rb_id_table *tbl, ID id)
 }
 
 void
+rb_id_table_foreach_with_replace(struct rb_id_table *tbl, rb_id_table_foreach_func_t *func, rb_id_table_update_callback_func_t *replace, void *data)
+{
+    int i, capa = tbl->capa;
+
+    for (i=0; i<capa; i++) {
+        if (ITEM_KEY_ISSET(tbl, i)) {
+            const id_key_t key = ITEM_GET_KEY(tbl, i);
+            enum rb_id_table_iterator_result ret = (*func)(Qundef, tbl->items[i].val, data);
+            assert(key != 0);
+
+            if (ret == ID_TABLE_REPLACE) {
+                VALUE val = tbl->items[i].val;
+                ret = (*replace)(NULL, &val, data, TRUE);
+                tbl->items[i].val = val;
+            }
+            else if (ret == ID_TABLE_STOP)
+                return;
+        }
+    }
+}
+
+void
 rb_id_table_foreach(struct rb_id_table *tbl, rb_id_table_foreach_func_t *func, void *data)
 {
     int i, capa = tbl->capa;