packfile: move packfile store into object source

The packfile store is a member of `struct object_database`, which means
that we have a single store per database. This doesn't really make much
sense though: each source connected to the database has its own set of
packfiles, so there is a conceptual mismatch here. This hasn't really
caused much of a problem in the past, but with the advent of pluggable
object databases this is becoming more of a problem because some of the
sources may not even use packfiles in the first place.

Move the packfile store down by one level from the object database into
the object database source. This ensures that each source now has its
own packfile store, and we can eventually start to abstract it away
entirely so that the caller doesn't even know what kind of store it
uses.

Note that we only need to adjust a relatively small number of callers,
way less than one might expect. This is because most callers are using
`repo_for_each_pack()`, which handles enumeration of all packfiles that
exist in the repository. So for now, none of these callers need to be
adapted. The remaining callers that iterate through the packfiles
directly and that need adjustment are those that are a bit more tangled
with packfiles. These will be adjusted over time.

Note that this patch only moves the packfile store, and there is still a
bunch of functions that seemingly operate on a packfile store but that
end up iterating over all sources. These will be adjusted in subsequent
commits.

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

1 files changed, 51 insertions, 45 deletions

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index e86b8f387a..7fd90a9996 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1529,49 +1529,53 @@ static int want_cruft_object_mtime(struct repository *r,
 				   const struct object_id *oid,
 				   unsigned flags, uint32_t mtime)
 {
-	struct packed_git **cache = packfile_store_get_kept_pack_cache(r->objects->packfiles, flags);
+	struct odb_source *source;
 
-	for (; *cache; cache++) {
-		struct packed_git *p = *cache;
-		off_t ofs;
-		uint32_t candidate_mtime;
+	for (source = r->objects->sources; source; source = source->next) {
+		struct packed_git **cache = packfile_store_get_kept_pack_cache(source->packfiles, flags);
 
-		ofs = find_pack_entry_one(oid, p);
-		if (!ofs)
-			continue;
+		for (; *cache; cache++) {
+			struct packed_git *p = *cache;
+			off_t ofs;
+			uint32_t candidate_mtime;
 
-		/*
-		 * We have a copy of the object 'oid' in a non-cruft
-		 * pack. We can avoid packing an additional copy
-		 * regardless of what the existing copy's mtime is since
-		 * it is outside of a cruft pack.
-		 */
-		if (!p->is_cruft)
-			return 0;
-
-		/*
-		 * If we have a copy of the object 'oid' in a cruft
-		 * pack, then either read the cruft pack's mtime for
-		 * that object, or, if that can't be loaded, assume the
-		 * pack's mtime itself.
-		 */
-		if (!load_pack_mtimes(p)) {
-			uint32_t pos;
-			if (offset_to_pack_pos(p, ofs, &pos) < 0)
+			ofs = find_pack_entry_one(oid, p);
+			if (!ofs)
 				continue;
-			candidate_mtime = nth_packed_mtime(p, pos);
-		} else {
-			candidate_mtime = p->mtime;
-		}
 
-		/*
-		 * We have a surviving copy of the object in a cruft
-		 * pack whose mtime is greater than or equal to the one
-		 * we are considering. We can thus avoid packing an
-		 * additional copy of that object.
-		 */
-		if (mtime <= candidate_mtime)
-			return 0;
+			/*
+			 * We have a copy of the object 'oid' in a non-cruft
+			 * pack. We can avoid packing an additional copy
+			 * regardless of what the existing copy's mtime is since
+			 * it is outside of a cruft pack.
+			 */
+			if (!p->is_cruft)
+				return 0;
+
+			/*
+			 * If we have a copy of the object 'oid' in a cruft
+			 * pack, then either read the cruft pack's mtime for
+			 * that object, or, if that can't be loaded, assume the
+			 * pack's mtime itself.
+			 */
+			if (!load_pack_mtimes(p)) {
+				uint32_t pos;
+				if (offset_to_pack_pos(p, ofs, &pos) < 0)
+					continue;
+				candidate_mtime = nth_packed_mtime(p, pos);
+			} else {
+				candidate_mtime = p->mtime;
+			}
+
+			/*
+			 * We have a surviving copy of the object in a cruft
+			 * pack whose mtime is greater than or equal to the one
+			 * we are considering. We can thus avoid packing an
+			 * additional copy of that object.
+			 */
+			if (mtime <= candidate_mtime)
+				return 0;
+		}
 	}
 
 	return -1;
@@ -1749,13 +1753,15 @@ static int want_object_in_pack_mtime(const struct object_id *oid,
 		}
 	}
 
-	for (e = the_repository->objects->packfiles->packs.head; e; e = e->next) {
-		struct packed_git *p = e->pack;
-		want = want_object_in_pack_one(p, oid, exclude, found_pack, found_offset, found_mtime);
-		if (!exclude && want > 0)
-			packfile_list_prepend(&the_repository->objects->packfiles->packs, p);
-		if (want != -1)
-			return want;
+	for (source = the_repository->objects->sources; source; source = source->next) {
+		for (e = source->packfiles->packs.head; e; e = e->next) {
+			struct packed_git *p = e->pack;
+			want = want_object_in_pack_one(p, oid, exclude, found_pack, found_offset, found_mtime);
+			if (!exclude && want > 0)
+				packfile_list_prepend(&source->packfiles->packs, p);
+			if (want != -1)
+				return want;
+		}
 	}
 
 	if (uri_protocols.nr) {