Re: [PATCH 08/10] bloom: split 'get_bloom_filter()' in two

On 8/3/2020 2:57 PM, Taylor Blau wrote:

'get_bloom_filter' takes a flag to control whether it will compute a
Bloom filter if the requested one is missing. In the next patch, we'll
add yet another flag to this method, which would force all but one
caller to specify an extra 'NULL' parameter at the end.

Instead of doing this, split 'get_bloom_filter' into two functions:
'get_bloom_filter' and 'get_or_compute_bloom_filter'. The former only
looks up a Bloom filter (and does not compute one if it's missing,
thus dropping the 'compute_if_not_present' flag). The latter does
compute missing Bloom filters, with an additional parameter to store
whether or not it needed to do so.

This simplifies many call-sites, since the majority of existing callers
to 'get_bloom_filter' do not want missing Bloom filters to be computed
(so they can drop the parameter entirely and use the simpler version of
the function).

+struct bloom_filter *get_or_compute_bloom_filter(struct repository *r,
+						 struct commit *c,
+						 int compute_if_not_present,
+						 int *computed)

Could we further simplify this by letting "computed" be the indicator
for whether we should compute the filter? If "computed" is NULL, then
we won't compute it directly. This allows us to reduce the "1, NULL)"
to "NULL)" in these callers:

+			struct bloom_filter *filter = get_or_compute_bloom_filter(ctx->r, c, 1, NULL);

+	filter = get_or_compute_bloom_filter(the_repository, c, 1, NULL);

Thanks,
-Stolee