diff --git a/libguile/hashtab.c b/libguile/hashtab.c index f3887c213..c703108cf 100644 --- a/libguile/hashtab.c +++ b/libguile/hashtab.c @@ -120,6 +120,26 @@ scm_fixup_weak_alist (SCM alist, size_t *removed_items) return result; } +static void +vacuum_weak_hash_table (SCM table) +{ + SCM buckets = SCM_HASHTABLE_VECTOR (table); + unsigned long k = SCM_SIMPLE_VECTOR_LENGTH (buckets); + size_t len = SCM_HASHTABLE_N_ITEMS (table); + + while (k--) + { + size_t removed; + SCM alist = SCM_SIMPLE_VECTOR_REF (buckets, k); + alist = scm_fixup_weak_alist (alist, &removed); + assert (removed <= len); + len -= removed; + SCM_SIMPLE_VECTOR_SET (buckets, k, alist); + } + + SCM_SET_HASHTABLE_N_ITEMS (table, len); +} + /* Packed arguments for `do_weak_bucket_fixup'. */ struct t_fixup_args @@ -651,12 +671,16 @@ scm_hash_fn_create_handle_x (SCM table, SCM obj, SCM init, } SCM_SETCDR (new_bucket, SCM_SIMPLE_VECTOR_REF (buckets, k)); SCM_SIMPLE_VECTOR_SET (buckets, k, new_bucket); - /* Update element count and maybe rehash the table. The - table might have too few entries here since weak hash - tables used with the hashx_* functions can not be - rehashed after GC. - */ SCM_HASHTABLE_INCREMENT (table); + + /* Maybe rehash the table. If it's a weak table, pump all of the + buckets first to remove stale links. If the weak table is of + the kind that gets lots of insertions of short-lived values, we + might never need to actually rehash. */ + if (SCM_HASHTABLE_WEAK_P (table) + && SCM_HASHTABLE_N_ITEMS (table) > SCM_HASHTABLE_UPPER (table)) + vacuum_weak_hash_table (table); + if (SCM_HASHTABLE_N_ITEMS (table) < SCM_HASHTABLE_LOWER (table) || SCM_HASHTABLE_N_ITEMS (table) > SCM_HASHTABLE_UPPER (table)) scm_i_rehash (table, hash_fn, closure, FUNC_NAME);