Class AsynchronousLock

source code

                        object --+        
                                 |        
portage.util.SlotObject.SlotObject --+    
                                     |    
     AsynchronousTask.AsynchronousTask --+
                                         |
                                        AsynchronousLock

This uses the portage.locks module to acquire a lock asynchronously, using either a thread (if available) or a subprocess.

The default behavior is to use a process instead of a thread, since there is currently no way to interrupt a thread that is waiting for a lock (notably, SIGINT doesn't work because python delivers all signals to the main thread).