Re: [libgpiod v2][PATCH V8 9/9] bindings: rust: Implement iterator for edge events

[Viresh Kumar <viresh.kumar@xxxxxxxxxx>]

On 02-11-22, 21:16, Kent Gibson wrote:
> It is generally frowned upon to patch your own patch within the same
> series, so drop the Suggested-by and squash this into patch 5.
> In this instance it is very handy for reviewing though, as the other
> patches look pretty clean to me...

I kept it separately for exactly this reason, I was planning to merge it
eventually with the other commits.

> > +pub struct Events<'a> {
> > +    buffer: &'a mut Buffer,
> > +    events: Vec<&'a Event>,
> > +    index: usize,
> > +}
> > +
> 
> Events is pub but not documented.
> 
> The events attribute is expensive - requiring a dynamic allocation for
> each snapshot.  And you create it unsized and push into it, which could
> require resizing and reallocation.
> And it is unnecessary - just have Events iterate over the appropriate
> indicies and get the ref from the buffer.

I had to do it this way as I wasn't able to get around an error I think. I
updated the code now based on suggestions, in my v9 branch, and I get it again:

error: lifetime may not live long enough
  --> libgpiod/src/event_buffer.rs:51:9
   |
45 | impl<'a> Iterator for Events<'a> {
   |      -- lifetime `'a` defined here
...
48 |     fn next(&mut self) -> Option<Self::Item> {
   |             - let's call the lifetime of this reference `'1`
...
51 |         event
   |         ^^^^^ associated function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'1`

error: could not compile `libgpiod` due to previous error

I will try to fix this on Monday now, unless you have an answer for me by then
:)

Thanks.

-- 
viresh