Re: [RFC] MI: Event notification

[Vladimir Prus <ghost@cs.msu.su>]

On Thursday 04 January 2007 23:49, Nick Roberts wrote:
>  > > The general idea is to report changes in program state to the frontend so
>  > > that it only updates the parts that need it.  For example, after "up"
>  > > frame_changed_hook triggers and the frontend knows it has to update the
>  > > locals display.
>  > 
>  > You mean, after "up" emitted explicitly by the user? If the frontend changes
>  > the frame itself, it does not need any notifications.
> 
> It might not be by clicking on a button but by typing "up" or even "u" from
> the console (GUD buffer).  In such a case how would the frontend know that
> the frame has changed?
> 
>  > > This means that stepping through a single frame should be much 
>  > > quicker.  If GDB enters a new frame during execution, stack_changed_hook
>  > > triggers and the frontend knows it has to update the call stack display. 
>  > > I would eventually like to add more hooks like target-changed-hook when
>  > > the user attaches to/detaches from a process, kills the process, or
>  > > selects a new target with the "file" command.
>  > 
>  > Is this all for user-typed commands? I wonder if notifications for those are
>  > really needed. Reloading entire UI state after a user command does not seem
>  > too bad -- because user is not likely to enter 10 commands per second anyway
>  > -- and is much simpler.
> 
> With a large stack and stepping through the program, I think it is very
> noticeable, which is why I frequently try to select a line to run to.

Stepping through the code and typing CLI commands are rather different
activities. For entering CLI, full UI state reload is not so problematic.

For stepping:

	1. I have a proposal for "-var-list --locals" that I think will
	make work with local variables very convenient and fast. I'll post
	that tomorrow.
	2. As for -stack-* -- if there any reason why that code cannot detect
	that stack has not changed and quickly return "cached" result.
	That will optimize all existing frontends automatically.
 
>  > > The hooks are inserted/removed through "interpreter-exec console
>  > > cli-command" 
>  > 
>  > Sorry, can you clarify?
> 
> In mi_cmd_interpreter_exec, there are calls to mi_insert_notify_hooks and
> mi_remove_notify_hooks.

Ok.

>  > > so I envisage not using MI commands like -exec-run, 
>  > > -exec-next, -stack-select-frame that change that state.
> 
> mi_cmd_interpreter_exec only gets called with "interpreter-exec" so there
> would be no event notification in this case.

I suppose frontend can check if the input starts with "-" and do full reload
in that case, anyway?

- Volodya