odb: move kept cache into struct packfile_store

The object database tracks a cache of "kept" packfiles, which is used by
git-pack-objects(1) to handle cruft objects. With the introduction of
the `struct packfile_store` we have a better place to host this cache
though.

Move the cache accordingly.

This moves the last bit of packfile-related state from the object
database into the packfile store. Adapt the comment for the `packfiles`
pointer in `struct object_database` to reflect this.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

odb.h

@@ -131,16 +131,8 @@ struct object_database {
 	struct commit_graph *commit_graph;
 	unsigned commit_graph_attempted : 1; /* if loading has been attempted */
 
-	/*
-	 * private data
-	 *
-	 * Should only be accessed directly by packfile.c and midx.c.
-	 */
+	/* Should only be accessed directly by packfile.c and midx.c. */
 	struct packfile_store *packfiles;
-	struct {
-		struct packed_git **packs;
-		unsigned flags;
-	} kept_pack_cache;
 
 	/*
 	 * This is meant to hold a *small* number of objects that you would

packfile.c

@@ -2091,19 +2091,19 @@ int find_pack_entry(struct repository *r, const struct object_id *oid, struct pa
 static void maybe_invalidate_kept_pack_cache(struct repository *r,
 					     unsigned flags)
 {
-	if (!r->objects->kept_pack_cache.packs)
+	if (!r->objects->packfiles->kept_cache.packs)
 		return;
-	if (r->objects->kept_pack_cache.flags == flags)
+	if (r->objects->packfiles->kept_cache.flags == flags)
 		return;
-	FREE_AND_NULL(r->objects->kept_pack_cache.packs);
-	r->objects->kept_pack_cache.flags = 0;
+	FREE_AND_NULL(r->objects->packfiles->kept_cache.packs);
+	r->objects->packfiles->kept_cache.flags = 0;
 }
 
 struct packed_git **kept_pack_cache(struct repository *r, unsigned flags)
 {
 	maybe_invalidate_kept_pack_cache(r, flags);
 
-	if (!r->objects->kept_pack_cache.packs) {
+	if (!r->objects->packfiles->kept_cache.packs) {
 		struct packed_git **packs = NULL;
 		size_t nr = 0, alloc = 0;
 		struct packed_git *p;
@@ -2126,11 +2126,11 @@ struct packed_git **kept_pack_cache(struct repository *r, unsigned flags)
 		ALLOC_GROW(packs, nr + 1, alloc);
 		packs[nr] = NULL;
 
-		r->objects->kept_pack_cache.packs = packs;
-		r->objects->kept_pack_cache.flags = flags;
+		r->objects->packfiles->kept_cache.packs = packs;
+		r->objects->packfiles->kept_cache.flags = flags;
 	}
 
-	return r->objects->kept_pack_cache.packs;
+	return r->objects->packfiles->kept_cache.packs;
 }
 
 int find_kept_pack_entry(struct repository *r,

packfile.h

@@ -64,6 +64,20 @@ struct packfile_store {
 	 */
 	struct packed_git *packs;
 
+	/*
+	 * Cache of packfiles which are marked as "kept", either because there
+	 * is an on-disk ".keep" file or because they are marked as "kept" in
+	 * memory.
+	 *
+	 * Should not be accessed directly, but via `kept_pack_cache()`. The
+	 * list of packs gets invalidated when the stored flags and the flags
+	 * passed to `kept_pack_cache()` mismatch.
+	 */
+	struct {
+		struct packed_git **packs;
+		unsigned flags;
+	} kept_cache;
+
 	/* A most-recently-used ordered version of the packs list. */
 	struct list_head mru;