repack-geometry: extract function to compute repacking split

We're about to add a second caller that wants to compute the repacking
split for a set of packfiles. Split out the function that computes this
split to prepare for that.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pks-t

repack-geometry.c

@@ -78,33 +78,32 @@ void pack_geometry_init(struct pack_geometry *geometry,
 	strbuf_release(&buf);
 }
 
-void pack_geometry_split(struct pack_geometry *geometry)
+static uint32_t compute_pack_geometry_split(struct packed_git **pack, size_t pack_nr,
+					    int split_factor)
 {
 	uint32_t i;
 	uint32_t split;
 	off_t total_size = 0;
 
-	if (!geometry->pack_nr) {
-		geometry->split = geometry->pack_nr;
-		return;
-	}
+	if (!pack_nr)
+		return 0;
 
 	/*
 	 * First, count the number of packs (in descending order of size) which
 	 * already form a geometric progression.
 	 */
-	for (i = geometry->pack_nr - 1; i > 0; i--) {
-		struct packed_git *ours = geometry->pack[i];
-		struct packed_git *prev = geometry->pack[i - 1];
+	for (i = pack_nr - 1; i > 0; i--) {
+		struct packed_git *ours = pack[i];
+		struct packed_git *prev = pack[i - 1];
 
-		if (unsigned_mult_overflows(geometry->split_factor,
+		if (unsigned_mult_overflows(split_factor,
 					    pack_geometry_weight(prev)))
 			die(_("pack %s too large to consider in geometric "
 			      "progression"),
 			    prev->pack_name);
 
 		if (pack_geometry_weight(ours) <
-		    geometry->split_factor * pack_geometry_weight(prev))
+		    split_factor * pack_geometry_weight(prev))
 			break;
 	}
 
@@ -130,21 +129,19 @@ void pack_geometry_split(struct pack_geometry *geometry)
 	 * the geometric progression.
 	 */
 	for (i = 0; i < split; i++) {
-		struct packed_git *p = geometry->pack[i];
+		struct packed_git *p = pack[i];
 
 		if (unsigned_add_overflows(total_size, pack_geometry_weight(p)))
 			die(_("pack %s too large to roll up"), p->pack_name);
 		total_size += pack_geometry_weight(p);
 	}
-	for (i = split; i < geometry->pack_nr; i++) {
-		struct packed_git *ours = geometry->pack[i];
+	for (i = split; i < pack_nr; i++) {
+		struct packed_git *ours = pack[i];
 
-		if (unsigned_mult_overflows(geometry->split_factor,
-					    total_size))
+		if (unsigned_mult_overflows(split_factor, total_size))
 			die(_("pack %s too large to roll up"), ours->pack_name);
 
-		if (pack_geometry_weight(ours) <
-		    geometry->split_factor * total_size) {
+		if (pack_geometry_weight(ours) < split_factor * total_size) {
 			if (unsigned_add_overflows(total_size,
 						   pack_geometry_weight(ours)))
 				die(_("pack %s too large to roll up"),
@@ -156,7 +153,13 @@ void pack_geometry_split(struct pack_geometry *geometry)
 			break;
 	}
 
-	geometry->split = split;
+	return split;
+}
+
+void pack_geometry_split(struct pack_geometry *geometry)
+{
+	geometry->split = compute_pack_geometry_split(geometry->pack, geometry->pack_nr,
+						      geometry->split_factor);
 }
 
 struct packed_git *pack_geometry_preferred_pack(struct pack_geometry *geometry)