Re: [PATCH v2 3/4] gdbsupport: add async parallel_for_each version

[Tom Tromey <tom@tromey.com>]

>>>>> "Simon" == simon marchi <simon.marchi@polymtl.ca> writes:

Simon> From: Simon Marchi <simon.marchi@polymtl.ca>
Simon> New in v2: make the global variable constexpr.

Simon> I would like to use gdb::parallel_for_each to implement the parallelism
Simon> of the DWARF unit indexing.  However, the existing implementation of
Simon> gdb::parallel_for_each is blocking, which doesn't work with the model
Simon> used by the DWARF indexer, which is asynchronous and callback-based.
Simon> Add an asynchronouys version of gdb::parallel_for_each that will be
Simon> suitable for this task.

Simon> This new version accepts a callback that is invoked when the parallel
Simon> for each is complete.

This looks good to me.

Simon> +	  const auto [batch_first, batch_last] = state->queue.pop_batch ();
Simon> +
Simon> +	  if (batch_first == batch_last)
Simon> +	    break;

If this was using iterator_range, it'd be easy enough to add an 'empty'
method to that object.

Tom