From 607bfb3627c32937ca7e542e462053bbb124ee06 Mon Sep 17 00:00:00 2001
From: Andrew Bauer <zonexpertconsulting@outlook.com>
Date: Thu, 18 Jun 2020 07:49:49 -0500
Subject: [PATCH] move StateChange subclass to signals.py

---
 ouimeaux/signals.py              | 39 ++++++++++++++++++++++++++-
 1 files changed, 26 insertions(+), 1 deletions(-)

diff --git a/ouimeaux/signals.py b/ouimeaux/signals.py
index b421aab..22547d2 100644
--- a/ouimeaux/signals.py
+++ b/ouimeaux/signals.py
@@ -1,4 +1,4 @@
-from pysignals import Signal, StateChange, receiver
+from pysignals import Signal, receiver
 
 # Work around a bug in pysignals when in the interactive interpreter
 import sys
@@ -6,6 +6,43 @@
 if _main:
     _main.__file__ = "__main__.py"
 
+class StateChange( Signal ):
+
+    def __init__(self, providing_args=None):
+        super(StateChange, self).__init__(providing_args)
+        self.sender_status = {}
+
+    def send(self, sender, **named):
+        """
+        Send signal from sender to all connected receivers *only if* the signal's
+        contents has changed.
+        If any receiver raises an error, the error propagates back through send,
+        terminating the dispatch loop, so it is quite possible to not have all
+        receivers called if a raises an error.
+        Arguments:
+            sender
+                The sender of the signal Either a specific object or None.
+            named
+                Named arguments which will be passed to receivers.
+        Returns a list of tuple pairs [(receiver, response), ... ].
+        """
+        responses = []
+        if not self.receivers:
+            return responses
+
+        sender_id = _make_id(sender)
+        if sender_id not in self.sender_status:
+            self.sender_status[sender_id] = {}
+
+        if self.sender_status[sender_id] == named:
+            return responses
+
+        self.sender_status[sender_id] = named
+
+        for receiver in self._live_receivers(sender_id):
+            response = receiver(signal=self, sender=sender, **named)
+            responses.append((receiver, response))
+        return responses
 
 # Fires when a device responds to a broadcast 
 discovered = Signal(providing_args=["address", "headers"])