Clear heap area when release object

ext/ilios/cluster.c

@@ -236,6 +236,7 @@ static void cluster_destroy(void *ptr)
     if (cassandra_cluster->cluster) {
         cass_cluster_free(cassandra_cluster->cluster);
     }
+    bzero(cassandra_cluster, sizeof(CassandraCluster));
     xfree(cassandra_cluster);
 }
 

ext/ilios/future.c

@@ -346,6 +346,7 @@ static void future_destroy(void *ptr)
         cass_future_free(cassandra_future->future);
     }
     uv_sem_destroy(&cassandra_future->sem);
+    bzero(cassandra_future, sizeof(CassandraFuture));
     xfree(cassandra_future);
 }
 

ext/ilios/nogvl.c

@@ -61,6 +61,9 @@ static void *nogvl_sem_wait_cb(void *ptr)
 
 void nogvl_sem_wait(uv_sem_t *sem)
 {
+    if (!sem) {
+        abort();
+    }
     // Releases GVL to run another thread while waiting
     rb_thread_call_without_gvl(nogvl_sem_wait_cb, sem, RUBY_UBF_PROCESS, 0);
 }

ext/ilios/result.c

@@ -245,6 +245,7 @@ static void result_destroy(void *ptr)
     if (cassandra_result->future) {
         cass_future_free(cassandra_result->future);
     }
+    bzero(cassandra_result, sizeof(CassandraResult));
     xfree(cassandra_result);
 }
 

ext/ilios/session.c

@@ -141,6 +141,7 @@ static void session_destroy(void *ptr)
     if (cassandra_session->connect_future) {
         cass_future_free(cassandra_session->connect_future);
     }
+    bzero(cassandra_session, sizeof(CassandraSession));
     xfree(cassandra_session);
 }
 

ext/ilios/statement.c

@@ -217,6 +217,7 @@ static void statement_destroy(void *ptr)
     if (cassandra_statement->statement) {
         cass_statement_free(cassandra_statement->statement);
     }
+    bzero(cassandra_statement, sizeof(CassandraStatement));
     xfree(cassandra_statement);
 }