msmith - in flumotion/trunk: . flumotion/twisted

[flumotion-commit at lists.fluendo.com]

Author: msmith
Date: Tue Feb 27 18:37:56 2007
New Revision: 4533

Modified:
   flumotion/trunk/ChangeLog
   flumotion/trunk/flumotion/twisted/fdserver.py
Log:
        * flumotion/twisted/fdserver.py:
          Comments to make wingo weep a little less.



Modified: flumotion/trunk/ChangeLog
==============================================================================
--- flumotion/trunk/ChangeLog	(original)
+++ flumotion/trunk/ChangeLog	Tue Feb 27 18:37:56 2007
@@ -1,5 +1,10 @@
 2007-02-27  Michael Smith  <msmith at fluendo.com>
 
+	* flumotion/twisted/fdserver.py:
+	  Comments to make wingo weep a little less.
+
+2007-02-27  Michael Smith  <msmith at fluendo.com>
+
 	* flumotion/component/feedcomponent.py:
 	* flumotion/component/feedcomponent010.py:
 	  Split removeFDCallback into removeClientCallback and

Modified: flumotion/trunk/flumotion/twisted/fdserver.py
==============================================================================
--- flumotion/trunk/flumotion/twisted/fdserver.py	(original)
+++ flumotion/trunk/flumotion/twisted/fdserver.py	Tue Feb 27 18:37:56 2007
@@ -35,7 +35,11 @@
 # and client.py
 # Thanks for the inspiration!
 
-# 16 byte long randomly-generated magic signature
+# Since we're doing this over a stream socket, our file descriptor messages
+# aren't guaranteed to be received alone; they could arrive along with some
+# unrelated data.
+# So, we prefix the message with a 16 byte magic signature, and a length,
+# and if we receive file descriptors decode based on this.
 MAGIC_SIGNATURE = "\xfd\xfc\x8e\x7f\x07\x47\xb9\xea" \
                   "\xa1\x75\xee\xd8\xdc\x36\xc8\xa3"
 
@@ -63,6 +67,12 @@
                 return main.CONNECTION_DONE
 
             if len(fds) > 0:
+                # Look for our magic cookie in (possibly) the midst of other
+                # data. Pass surrounding chunks, if any, onto dataReceived(), 
+                # which (undocumentedly) must return None unless a failure 
+                # occurred.
+                # Pass the actual FDs and their message to 
+                # fileDescriptorsReceived()
                 offset = message.find(MAGIC_SIGNATURE)
                 if offset < 0:
                     raise TypeError("Bad signature")