Python3 Migrate

venv/lib/python3.7/site-packages/pykka/messages.py

@@ -0,0 +1,77 @@
+"""
+The :mod:`pykka.messages` module contains Pykka's own actor messages.
+
+In general, you should not need to use any of these classes. However, they have
+been made part of the public API so that certain optimizations can be done
+without touching Pykka's internals.
+
+An example is to combine :meth:`~pykka.ActorRef.ask` and :class:`ProxyCall`
+to call a method on an actor without having to spend any resources on creating
+a proxy object::
+
+    reply = actor_ref.ask(
+        ProxyCall(
+            attr_path=['my_method'],
+            args=['foo'],
+            kwargs={'bar': 'baz'}
+        )
+    )
+
+Another example is to use :meth:`~pykka.ActorRef.tell` instead of
+:meth:`~pykka.ActorRef.ask` for the proxy method call, and thus avoid the
+creation of a future for the return value if you don't need it.
+
+It should be noted that these optimizations should only be necessary in very
+special circumstances.
+"""
+
+import warnings
+from collections import namedtuple
+
+
+# Internal actor messages
+_ActorStop = namedtuple('ActorStop', [])
+
+# Public proxy messages
+# TODO Add docstrings to classes and attributes once we drop Python 2.7 support
+ProxyCall = namedtuple('ProxyCall', ['attr_path', 'args', 'kwargs'])
+ProxyGetAttr = namedtuple('ProxyGetAttr', ['attr_path'])
+ProxySetAttr = namedtuple('ProxySetAttr', ['attr_path', 'value'])
+
+
+def _upgrade_internal_message(message):
+    """Filter that upgrades dict-based internal messages to the new format.
+
+    This is needed for a transitional period because Mopidy < 3 uses
+    the old internal message format directly, and maybe others.
+    """
+
+    if not isinstance(message, dict):
+        return message
+    if not message.get('command', '').startswith('pykka_'):
+        return message
+
+    warnings.warn(
+        'Pykka received a dict-based internal message. '
+        'This is deprecated and will be unsupported in the future. '
+        'Message: {!r}'.format(message),
+        DeprecationWarning,
+    )
+
+    command = message.get('command')
+    if command == 'pykka_stop':
+        return _ActorStop()
+    elif command == 'pykka_call':
+        return ProxyCall(
+            attr_path=message['attr_path'],
+            args=message['args'],
+            kwargs=message['kwargs'],
+        )
+    elif command == 'pykka_getattr':
+        return ProxyGetAttr(attr_path=message['attr_path'])
+    elif command == 'pykka_setattr':
+        return ProxySetAttr(
+            attr_path=message['attr_path'], value=message['value']
+        )
+    else:
+        raise ValueError('Unknown internal message: {!r}'.format(message))