From 8f0f7908e1ce9cef7dc5dafa9c75a07fb21d5d1d Mon Sep 17 00:00:00 2001
From: Sven Augustin <sven.augustin@psi.ch>
Date: Sat, 10 Dec 2022 22:42:27 +0100
Subject: [PATCH] added semaphore for using the callback; keep the monitoring
 thread running, only enable/disable the callback (removes the dead time for
 connecting during start)

---
 slic/core/sensor/bssensor.py | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/slic/core/sensor/bssensor.py b/slic/core/sensor/bssensor.py
index d4d67515..04e68a1d 100644
--- a/slic/core/sensor/bssensor.py
+++ b/slic/core/sensor/bssensor.py
@@ -9,12 +9,16 @@ MSG_MISSING_TYPE = "'type' channel field not found. Parse as 64-bit floating-poi
 
 class BSSensor(Sensor):
 
-    def start(self):
-        self.thread = thread = BSMonitorThread(self.name, self._collect)
+    def __init__(self, name, **kwargs):
+        super().__init__(name, **kwargs)
+        self.thread = thread = BSMonitorThread(name, self._collect)
         thread.start()
 
+    def start(self):
+        self.thread.enable_callback()
+
     def stop(self):
-        self.thread.stop()
+        self.thread.disable_callback()
 
 
 
@@ -24,21 +28,30 @@ class BSMonitorThread(Thread):
         super().__init__()
         self.name = name
         self.callback = callback
+        self.use_callback = Event()
         self.running = Event()
 
     def run(self):
+        use_callback = self.use_callback
         running = self.running
         running.set()
         with BSChannel(self.name) as chan:
             while running.is_set():
                 value = chan.get()
-                self.callback(value)
+                if use_callback.is_set():
+                    self.callback(value)
         running.clear()
 
     def stop(self):
         self.running.clear()
         self.join()
 
+    def enable_callback(self):
+        self.use_callback.set()
+
+    def disable_callback(self):
+        self.use_callback.clear()
+
 
 
 class BSChannel(source):