implement simple Promise for run_async/conversationhandler

jh0ker · jh0ker · commit a975caea770a · 2016-06-23T23:54:15.000+02:00
diff --git a/telegram/ext/conversationhandler.py b/telegram/ext/conversationhandler.py
@@ -22,6 +22,7 @@
 
 from telegram import Update
 from telegram.ext import Handler
+from telegram.utils.promise import Promise
 
 
 class ConversationHandler(Handler):
@@ -111,6 +112,10 @@ def check_update(self, update):
         key = (chat.id, user.id) if chat else (None, user.id)
         state = self.conversations.get(key)
 
+        if isinstance(state, Promise):
+            self.logger.debug('waiting for promise...')
+            state = state.result()
+
         self.logger.debug('selecting conversation %s with state %s' % (str(key), str(state)))
 
         handler = None
diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
@@ -30,6 +30,7 @@
 from telegram.utils import request
 from telegram.ext.handler import Handler
 from telegram.utils.deprecate import deprecate
+from telegram.utils.promise import Promise
 
 logging.getLogger(__name__).addHandler(NullHandler())
 
@@ -45,17 +46,16 @@ def _pooled():
     A wrapper to run a thread in a thread pool
     """
     while 1:
-        try:
-            func, args, kwargs = ASYNC_QUEUE.get()
+        promise = ASYNC_QUEUE.get()
 
         # If unpacking fails, the thread pool is being closed from Updater._join_async_threads
-        except TypeError:
+        if not isinstance(promise, Promise):
             logging.getLogger(__name__).debug("Closing run_async thread %s/%d" %
                                               (current_thread().getName(), len(ASYNC_THREADS)))
             break
 
         try:
-            func(*args, **kwargs)
+            promise.run()
 
         except:
             logging.getLogger(__name__).exception("run_async function raised exception")
@@ -80,7 +80,9 @@ def async_func(*args, **kwargs):
         """
         A wrapper to run a function in a thread
         """
-        ASYNC_QUEUE.put((func, args, kwargs))
+        promise = Promise(func, args, kwargs)
+        ASYNC_QUEUE.put(promise)
+        return promise
 
     return async_func
 
diff --git a/telegram/utils/promise.py b/telegram/utils/promise.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+#
+# A library that provides a Python interface to the Telegram Bot API
+# Copyright (C) 2015-2016
+# Leandro Toledo de Souza <devs@python-telegram-bot.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser Public License for more details.
+#
+# You should have received a copy of the GNU Lesser Public License
+# along with this program.  If not, see [http://www.gnu.org/licenses/].
+""" This module contains the Promise class """
+
+from threading import Event
+
+
+class Promise(object):
+    """A simple Promise implementation for the run_async decorator"""
+
+    def __init__(self, pooled_function, args, kwargs):
+        self.pooled_function = pooled_function
+        self.args = args
+        self.kwargs = kwargs
+        self._done = Event()
+        self._result = None
+
+    def run(self):
+        try:
+            self._result = self.pooled_function(*self.args, **self.kwargs)
+
+        except:
+            raise
+
+        finally:
+            self._done.set()
+
+    def result(self, timeout=None):
+        self._done.wait(timeout=timeout)
+        return self._result
