1 files changed, 48 insertions, 0 deletions
diff --git a/distbuild/eventsrc.py b/distbuild/eventsrc.py
new file mode 100644
index 00000000..11bb16e8
--- /dev/null
+++ b/distbuild/eventsrc.py
@@ -0,0 +1,48 @@
+# mainloop/eventsrc.py -- interface for event sources
+#
+# Copyright 2012 Codethink Limited.
+# All rights reserved.
+
+
+class EventSource(object):
+
+    '''A source of events for state machines.
+    
+    This is a base class.
+    
+    An event source watches one file descriptor, and returns events
+    related to it. The events may vary depending on the file descriptor.
+    The actual watching is done using select.select.
+    
+    '''
+    
+    def get_select_params(self):
+        '''Return parameters to use for select for this event source.
+        
+        Three lists of file descriptors, and a timeout are returned.
+        The three lists and the timeout are used as arguments to the 
+        select.select function, though they may be manipulated and
+        combined with return values from other event sources.
+        
+        '''
+        
+        return [], [], [], None
+
+    def get_events(self, r, w, x):
+        '''Return events related to this file descriptor.
+        
+        The arguments are the return values of select.select.
+        
+        '''
+        
+        return []
+
+    def is_finished(self):
+        '''Is this event source finished?
+        
+        It's finished if it won't ever return any new events.
+        
+        '''
+        
+        return False
+