Of course, the input lock must be held when doing the (non-blocking)

recv() call too, else there'd still be a race condition (two threads
both receiving some data, and then the last to read processing it
first, which would be a disaster).

src/ZEO/zrpc/smac.py

@@ -13,7 +13,7 @@
 ##############################################################################
 """Sized message async connections
 
-$Id: smac.py,v 1.31 2002/09/29 03:22:28 gvanrossum Exp $
+$Id: smac.py,v 1.32 2002/09/29 07:51:37 gvanrossum Exp $
 """
 
 import asyncore, struct
@@ -89,6 +89,8 @@ class SizedMessageAsyncConnection(asyncore.dispatcher):
         return 1
 
     def handle_read(self):
+        self.__input_lock.acquire()
+        try:
             # Use a single __inp buffer and integer indexes to make this fast.
             try:
                 d = self.recv(8096)
@@ -99,8 +101,6 @@ class SizedMessageAsyncConnection(asyncore.dispatcher):
             if not d:
                 return
 
-        self.__input_lock.acquire()
-        try:
             input_len = self.__input_len + len(d)
             msg_size = self.__msg_size
             state = self.__state