ext/rev/rev_loop.c in rev-0.1.3 vs ext/rev/rev_loop.c in rev-0.1.4

@@ -54,10 +54,11 @@
 {
   struct Rev_Loop *loop = (struct Rev_Loop *)xmalloc(sizeof(struct Rev_Loop));
 
   loop->ev_loop = 0;
 
+  loop->running = 0;
   loop->events_received = 0;
   loop->eventbuf_size = DEFAULT_EVENTBUF_SIZE;
   loop->eventbuf = (struct Rev_Event *)xmalloc(sizeof(struct Rev_Event) * DEFAULT_EVENTBUF_SIZE);
 
   return Data_Wrap_Struct(klass, Rev_Loop_mark, Rev_Loop_free, loop);
@@ -175,14 +176,20 @@
 static VALUE Rev_Loop_run_once(VALUE self)
 {
   struct Rev_Loop *loop_data;
   Data_Get_Struct(self, struct Rev_Loop, loop_data);
 
+  if(loop_data->running)
+    rb_raise(rb_eRuntimeError, "cannot run loop from within a callback");
+
   assert(loop_data->ev_loop && !loop_data->events_received);
+
+  loop_data->running = 1;
   rb_thread_blocking_region(Rev_Loop_run_once_blocking, loop_data->ev_loop, RB_UBF_DFL, 0);
   Rev_Loop_dispatch_events(loop_data);
   loop_data->events_received = 0;
+  loop_data->running = 0;
 
   return Qnil;
 }
 
 static VALUE Rev_Loop_run_once_blocking(void *ptr) 
@@ -203,13 +210,19 @@
 static VALUE Rev_Loop_run_nonblock(VALUE self)
 {
   struct Rev_Loop *loop_data;
   Data_Get_Struct(self, struct Rev_Loop, loop_data);
 
+  if(loop_data->running)
+    rb_raise(rb_eRuntimeError, "cannot run loop from within a callback");
+
   assert(loop_data->ev_loop && !loop_data->events_received);
+
+  loop_data->running = 1;
   ev_loop(loop_data->ev_loop, EVLOOP_NONBLOCK);
   Rev_Loop_dispatch_events(loop_data);
   loop_data->events_received = 0;
+  loop_data->running = 0;
 
   return Qnil;
 }
 
 static void Rev_Loop_dispatch_events(struct Rev_Loop *loop_data)