From 6a6236e704ce67e174479a766331a76944dced17 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Krist=C3=B3f=20T=C3=B3th?= <kristof.toth@avatao.com>
Date: Wed, 7 Mar 2018 10:12:58 +0100
Subject: [PATCH] Refactor callback subscription stuff to a mixin

---
 lib/tfw/components/history_monitor.py       | 13 +++++--------
 lib/tfw/components/mixins/callback_mixin.py | 17 +++++++++++++++++
 lib/tfw/fsm_base.py                         | 16 +++++-----------
 lib/tfw/networking/server/tfw_server.py     |  2 +-
 src/demo/event_handler_main.py              |  2 +-
 5 files changed, 29 insertions(+), 21 deletions(-)
 create mode 100644 lib/tfw/components/mixins/callback_mixin.py

diff --git a/lib/tfw/components/history_monitor.py b/lib/tfw/components/history_monitor.py
index f07a57b..9d8abf6 100644
--- a/lib/tfw/components/history_monitor.py
+++ b/lib/tfw/components/history_monitor.py
@@ -2,6 +2,8 @@ from watchdog.observers import Observer
 from watchdog.events import PatternMatchingEventHandler
 from os.path import dirname
 
+from tfw.components.mixins.callback_mixin import CallbackMixin
+
 
 class CallbackEventHandler(PatternMatchingEventHandler):
     def __init__(self, files, *callbacks):
@@ -13,12 +15,12 @@ class CallbackEventHandler(PatternMatchingEventHandler):
             callback()
 
 
-class HistoryMonitor:
+class HistoryMonitor(CallbackMixin):
     def __init__(self, histfile):
+        CallbackMixin.__init__(self)
         self.histfile = histfile
         self._history = []
         self._last_length = len(self._history)
-        self._callbacks = []
         self.observer = Observer()
         self.observer.schedule(CallbackEventHandler([self.histfile],
                                                     self._fetch_history,
@@ -29,10 +31,6 @@ class HistoryMonitor:
     def history(self):
         return self._history
 
-    @property
-    def callbacks(self):
-        return self._callbacks
-
     def _fetch_history(self):
         self._last_length = len(self._history)
         with open(self.histfile, 'r') as ifile:
@@ -40,8 +38,7 @@ class HistoryMonitor:
 
     def _invoke_callbacks(self):
         if self._last_length < len(self._history):
-            for callback in self.callbacks:
-                callback(self.history)
+            self._execute_callbacks(self.history)
 
     def watch(self):
         self.observer.start()
diff --git a/lib/tfw/components/mixins/callback_mixin.py b/lib/tfw/components/mixins/callback_mixin.py
new file mode 100644
index 0000000..c7a97b0
--- /dev/null
+++ b/lib/tfw/components/mixins/callback_mixin.py
@@ -0,0 +1,17 @@
+from functools import partial
+
+
+class CallbackMixin:
+    def __init__(self):
+        self._callbacks = []
+
+    def subscribe_callback(self, callback, *args, **kwargs):
+        fun = partial(callback, *args, **kwargs)
+        self._callbacks.append(fun)
+
+    def unsubscribe_callback(self, callback):
+        self._callbacks.remove(callback)
+
+    def _execute_callbacks(self, *args, **kwargs):
+        for callback in self._callbacks:
+            callback(*args, **kwargs)
diff --git a/lib/tfw/fsm_base.py b/lib/tfw/fsm_base.py
index 04494e6..b46a563 100644
--- a/lib/tfw/fsm_base.py
+++ b/lib/tfw/fsm_base.py
@@ -1,13 +1,14 @@
 from typing import List
-
 from transitions import Machine
 
+from tfw.components.mixins.callback_mixin import CallbackMixin
 
-class FSMBase:
+
+class FSMBase(CallbackMixin):
     states, transitions = [], []
 
     def __init__(self, initial: str = None, accepted_states: List[str] = None):
-        self.callbacks = []
+        CallbackMixin.__init__(self)
         self.accepted_states = accepted_states or [self.states[-1]]
         self.machine = Machine(model=self,
                                states=self.states,
@@ -18,14 +19,7 @@ class FSMBase:
                                after_state_change='execute_callbacks')
 
     def execute_callbacks(self, event_data):
-        for callback in self.callbacks:
-            callback(event_data.kwargs)
-
-    def subscribe(self, callback):
-        self.callbacks.append(callback)
-
-    def unsubscribe(self, callback):
-        self.callbacks.remove(callback)
+        self._execute_callbacks(event_data.kwargs)
 
     def is_solved(self):
         return self.state in self.accepted_states
diff --git a/lib/tfw/networking/server/tfw_server.py b/lib/tfw/networking/server/tfw_server.py
index 8b7d1f3..b076f9f 100644
--- a/lib/tfw/networking/server/tfw_server.py
+++ b/lib/tfw/networking/server/tfw_server.py
@@ -14,7 +14,7 @@ class TFWServer:
         self._fsm = fsm_type()
         self._fsm_updater = FSMUpdater(self._fsm)
         self._fsm_manager = FSMManager(self._fsm)
-        self._fsm.subscribe(self._fsm_updater.update)
+        self._fsm.subscribe_callback(self._fsm_updater.update)
 
         self.application = Application(
             [(r'/ws', ZMQWebSocketProxy, {'make_response': self.make_response,
diff --git a/src/demo/event_handler_main.py b/src/demo/event_handler_main.py
index 8500d09..9d5976c 100644
--- a/src/demo/event_handler_main.py
+++ b/src/demo/event_handler_main.py
@@ -11,7 +11,7 @@ log = logging.getLogger(__name__)
 if __name__ == '__main__':
     ide = SourceCodeEventHandler('webide', tfwenv.WEBIDE_WD)
     terminado = TerminadoEventHandler('shell')
-    terminado.historymonitor.callbacks.append(lambda hist: log.debug('User executed command: "{}"'.format(hist[-1])))
+    terminado.historymonitor.subscribe_callback(lambda hist: log.debug('User executed command: "{}"'.format(hist[-1])))
     processmanager = ProcessManagingEventHandler('processmanager', ide.monitor)
 
     eventhandlers = {ide, terminado, processmanager}