make simulator threads pre-emptible

1 files changed, 21 insertions, 0 deletions

diff --git a/lib/utils/threading.py b/lib/utils/threading.py
new file mode 100644
index 00000000..7bb90d1b
--- /dev/null
+++ b/lib/utils/threading.py
@@ -0,0 +1,21 @@
+import threading
+
+from ..exceptions import InkstitchException
+from ..debug import debug
+
+
+class ExitThread(InkstitchException):
+    """This exception is thrown in a thread to cause it to terminate.
+
+    Presumably we should only catch this at the thread's top level.
+    """
+    pass
+
+
+_default_stop_flag = threading.Event()
+
+
+def check_stop_flag():
+    if getattr(threading.current_thread(), 'stop', _default_stop_flag).is_set():
+        debug.log("exiting thread")
+        raise ExitThread()