Re: proc based observers

[Mark Wielaard <mark at klomp dot org>]

On Mon, 2007-06-18 at 16:47 -0400, Sami Wagiaalla wrote:
> > Do you have some examples of code that does that in frysk at the moment?
> >   
> There are a couple of instances in the gui. Here is an example from 
> Ftrace.java:
> 
> ProcObserver.ProcTasks tasksObserver = new ProcObserver.ProcTasks()
>   {
>     public void existingTask (Task task)
>     {
>       handleTask(task);
>     }
> 
>     public void taskAdded (Task task)
>     {
>       handleTask(task);
>     }
> [...]
>   };
> 
> 
> Then handle task does this:
> 
> synchronized void handleTask (Task task)
>   {
>     task.requestAddSyscallObserver(syscallObserver);
>     task.requestAddForkedObserver(forkedObserver);

Yeah, that is a nice way to easily add observers to all Tasks of a Proc
now and in the future (this should really also be added to fstep, which
currently only traces the main task, I have updated the bug report).

> The history behind this is interesting:
> 
> We used to have some proc observers, but we wanted fine grain control so 
> everything was moved down to tasks. then we wanted a safe way of getting 
> a procs tasks, so we created ProcTasksObserver.

Is there any functional difference between the old and the new way?

Cheers,

Mark