midx-write.c: factor out common want_included_pack() routine

When performing a 'git multi-pack-index repack', the MIDX machinery
tries to aggregate MIDX'd packs together either to (a) fill the given
`--batch-size` argument, or (b) combine all packs together.

In either case (using the `midx-write.c::fill_included_packs_batch()` or
`midx-write.c::fill_included_packs_all()` function, respectively), we
evaluate whether or not we want to repack each MIDX'd pack, according to
whether or it is loadable, kept, cruft, or non-empty.

Between the two `fill_included_packs_` callers, they both care about the
same conditions, except for `fill_included_packs_batch()` which also
cares that the pack is non-empty.

We could extract two functions (say, `want_included_pack()` and a
`_nonempty()` variant), but this is not necessary. For the case in
`fill_included_packs_all()` which does not check the pack size, we add
all of the pack's objects assuming that the pack meets all other
criteria. But if the pack is empty in the first place, we add all of its
zero objects, so whether or not we "accept" or "reject" it in the first
place is irrelevant.

This change improves the readability in both `fill_included_packs_`
functions.

Signed-off-by: Taylor Blau <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ttaylorr

midx-write.c

@@ -1349,6 +1349,24 @@ static int compare_by_mtime(const void *a_, const void *b_)
 	return 0;
 }
 
+static int want_included_pack(struct repository *r,
+			      struct multi_pack_index *m,
+			      int pack_kept_objects,
+			      uint32_t pack_int_id)
+{
+	struct packed_git *p;
+	if (prepare_midx_pack(r, m, pack_int_id))
+		return 0;
+	p = m->packs[pack_int_id];
+	if (!pack_kept_objects && p->pack_keep)
+		return 0;
+	if (p->is_cruft)
+		return 0;
+	if (open_pack_index(p) || !p->num_objects)
+		return 0;
+	return 1;
+}
+
 static int fill_included_packs_all(struct repository *r,
 				   struct multi_pack_index *m,
 				   unsigned char *include_pack)
@@ -1359,11 +1377,7 @@ static int fill_included_packs_all(struct repository *r,
 	repo_config_get_bool(r, "repack.packkeptobjects", &pack_kept_objects);
 
 	for (i = 0; i < m->num_packs; i++) {
-		if (prepare_midx_pack(r, m, i))
-			continue;
-		if (!pack_kept_objects && m->packs[i]->pack_keep)
-			continue;
-		if (m->packs[i]->is_cruft)
+		if (!want_included_pack(r, m, pack_kept_objects, i))
 			continue;
 
 		include_pack[i] = 1;
@@ -1410,13 +1424,7 @@ static int fill_included_packs_batch(struct repository *r,
 		struct packed_git *p = m->packs[pack_int_id];
 		size_t expected_size;
 
-		if (!p)
-			continue;
-		if (!pack_kept_objects && p->pack_keep)
-			continue;
-		if (p->is_cruft)
-			continue;
-		if (open_pack_index(p) || !p->num_objects)
+		if (!want_included_pack(r, m, pack_kept_objects, pack_int_id))
 			continue;
 
 		expected_size = st_mult(p->pack_size,