Simplify argument count checking

syncplay/client.py

@@ -5,7 +5,10 @@ import time
 from twisted.internet import reactor
 from twisted.internet.protocol import ClientFactory
 
-from .network_utils import CommandProtocol
+from .network_utils import (
+    arg_count,
+    CommandProtocol,
+)
 from .utils import parse_state
 
 
@@ -26,6 +29,7 @@ class SyncClientProtocol(CommandProtocol):
         self.manager.stop()
         CommandProtocol.handle_error(self, args)
 
+    @arg_count(3, 4)
     def handle_connected_state(self, args):
         args = parse_state(args)
         if not args:
@@ -36,10 +40,8 @@ class SyncClientProtocol(CommandProtocol):
 
         self.manager.update_global_state(counter, paused, position, name)
 
+    @arg_count(1)
     def handle_connected_ping(self, args):
-        if not len(args) == 1:
-            self.drop_with_error('Invalid arguments')
-            return
         self.send_message('pong', args[0])
 
     def send_state(self, counter, paused, position):
@@ -162,8 +164,9 @@ class Manager(object):
         self.protocol = protocol
         self.schedule_send_status()
         self.send_filename()
-        if self.player is None:
+        if self.make_player:
             self.make_player(self)
+            self.make_player = None
 
 
     def schedule_ask_player(self, when=0.2):

syncplay/network_utils.py

@@ -5,6 +5,8 @@ try:
 except ImportError:
     from StringIO import StringIO
 
+from functools import wraps
+
 from twisted.internet.defer import succeed
 from twisted.internet.protocol import (
     ProcessProtocol,
@@ -20,6 +22,17 @@ from .utils import (
     split_args,
 )
 
+def arg_count(minimum, maximum=None):
+    def decorator(f):
+        @wraps(f)
+        def wrapper(self, args):
+            if ((len(args) != minimum) if maximum is None else not (minimum <= len(args) <= maximum)):
+                self.drop_with_error('Invalid arguments')
+                return
+            return f(self, args)
+        return wrapper
+    return decorator
+
 class CommandProtocol(LineReceiver):
     states = None
 

syncplay/server.py

@@ -6,7 +6,10 @@ import random
 from twisted.internet import reactor
 from twisted.internet.protocol import Factory
 
-from .network_utils import CommandProtocol
+from .network_utils import (
+    arg_count,
+    CommandProtocol,
+)
 from .utils import parse_state
 
 random.seed()
@@ -32,6 +35,7 @@ class SyncServerProtocol(CommandProtocol):
         self.factory.add_watcher(self, args[0])
         self.change_state('connected')
 
+    @arg_count(3)
     def handle_connected_state(self, args):
         args = parse_state(args)
         if not args:
@@ -42,11 +46,8 @@ class SyncServerProtocol(CommandProtocol):
 
         self.factory.update_state(self, counter, paused, position)
 
+    @arg_count(1)
     def handle_connected_seek(self, args):
-        if not len(args) == 1:
-            self.drop_with_error('Invalid arguments')
-            return
-
         try:
             position = int(args[0])
         except ValueError:
@@ -56,17 +57,13 @@ class SyncServerProtocol(CommandProtocol):
 
         self.factory.seek(self, position)
 
+    @arg_count(1)
     def handle_connected_pong(self, args):
-        if not len(args) == 1:
-            self.drop_with_error('Invalid arguments')
-            return
         self.factory.pong_received(self, args[0])
 
+    @arg_count(1)
     def handle_connected_playing(self, args):
-        if not len(args) == 1:
-            self.drop_with_error('Invalid arguments')
-            return
-        #self.factory.pong_received(self, args[0])
+        pass
 
     def __hash__(self):
         return hash('|'.join((