Event Channels

[Dave Camp <campd oit edu>]

Here are my thoughts on the event channels.

First of all, I think there should be two event channels:  An 
administrative channel, and a target event channel (better names?).  
The administrative channel would handle changes in the Debugger.  For
example, the following notifications would be sent on the administrative
event channel:
	* program loaded
	* program unloaded
        * ui component started
        * debugger exiting

The target channel would handle events on the program/target itself:
	* program started
	* breakpoint hit
	* value changed
	* program stopped
 
We will be able to create a third event channel, add both event channels 
to the third, and have a single unified channel if desired.  To do this,
both channels would need to be using the same message format.

Here is a possible (very simple) event format:

enum EventSource {
	ADMINISTRATIVE_EVENT,
	TARGET_EVENT
};

struct DebugEvent {
	EventSource source;  // Useful when using composed channels.
	long event_id;       // An event identifier.
	CORBA_any data;      // Any message-dependent data.
};