packfile: move MIDX into packfile store

The multi-pack index still is tracked as a member of the object database
source, but ultimately the MIDX is always tied to one specific packfile
store.

Move the structure into `struct packfile_store` accordingly. This
ensures that the packfile store now keeps track of all data related to
packfiles.

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

Author: pks-t

midx.c

@@ -96,7 +96,7 @@ static int midx_read_object_offsets(const unsigned char *chunk_start,
 struct multi_pack_index *get_multi_pack_index(struct odb_source *source)
 {
 	packfile_store_prepare(source->packfiles);
-	return source->midx;
+	return source->packfiles->midx;
 }
 
 static struct multi_pack_index *load_multi_pack_index_one(struct odb_source *source,
@@ -709,12 +709,12 @@ int prepare_multi_pack_index_one(struct odb_source *source)
 	if (!r->settings.core_multi_pack_index)
 		return 0;
 
-	if (source->midx)
+	if (source->packfiles->midx)
 		return 1;
 
-	source->midx = load_multi_pack_index(source);
+	source->packfiles->midx = load_multi_pack_index(source);
 
-	return !!source->midx;
+	return !!source->packfiles->midx;
 }
 
 int midx_checksum_valid(struct multi_pack_index *m)
@@ -803,9 +803,9 @@ void clear_midx_file(struct repository *r)
 		struct odb_source *source;
 
 		for (source = r->objects->sources; source; source = source->next) {
-			if (source->midx)
-				close_midx(source->midx);
-			source->midx = NULL;
+			if (source->packfiles->midx)
+				close_midx(source->packfiles->midx);
+			source->packfiles->midx = NULL;
 		}
 	}
 

odb.c

@@ -1078,14 +1078,8 @@ struct object_database *odb_new(struct repository *repo,
 void odb_close(struct object_database *o)
 {
 	struct odb_source *source;
-
-	for (source = o->sources; source; source = source->next) {
+	for (source = o->sources; source; source = source->next)
 		packfile_store_close(source->packfiles);
-		if (source->midx)
-			close_midx(source->midx);
-		source->midx = NULL;
-	}
-
 	close_commit_graph(o);
 }
 

odb.h

@@ -54,13 +54,6 @@ struct odb_source {
 	/* Should only be accessed directly by packfile.c and midx.c. */
 	struct packfile_store *packfiles;
 
-	/*
-	 * private data
-	 *
-	 * should only be accessed directly by packfile.c and midx.c
-	 */
-	struct multi_pack_index *midx;
-
 	/*
 	 * Figure out whether this is the local source of the owning
 	 * repository, which would typically be its ".git/objects" directory.

packfile.c

@@ -990,7 +990,8 @@ static void prepare_pack(const char *full_name, size_t full_name_len,
 	size_t base_len = full_name_len;
 
 	if (strip_suffix_mem(full_name, &base_len, ".idx") &&
-	    !(data->source->midx && midx_contains_pack(data->source->midx, file_name))) {
+	    !(data->source->packfiles->midx &&
+	      midx_contains_pack(data->source->packfiles->midx, file_name))) {
 		char *trimmed_path = xstrndup(full_name, full_name_len);
 		packfile_store_load_pack(data->source->packfiles,
 					 trimmed_path, data->source->local);
@@ -1087,8 +1088,8 @@ struct packfile_list_entry *packfile_store_get_packs(struct packfile_store *stor
 {
 	packfile_store_prepare(store);
 
-	if (store->source->midx) {
-		struct multi_pack_index *m = store->source->midx;
+	if (store->midx) {
+		struct multi_pack_index *m = store->midx;
 		for (uint32_t i = 0; i < m->num_packs + m->num_packs_in_base; i++)
 			prepare_midx_pack(m, i);
 	}
@@ -2094,7 +2095,7 @@ static int find_pack_entry(struct packfile_store *store,
 	struct packfile_list_entry *l;
 
 	packfile_store_prepare(store);
-	if (store->source->midx && fill_midx_entry(store->source->midx, oid, e))
+	if (store->midx && fill_midx_entry(store->midx, oid, e))
 		return 1;
 
 	for (l = store->packs.head; l; l = l->next) {
@@ -2454,6 +2455,9 @@ void packfile_store_close(struct packfile_store *store)
 			BUG("want to close pack marked 'do-not-close'");
 		close_pack(e->pack);
 	}
+	if (store->midx)
+		close_midx(store->midx);
+	store->midx = NULL;
 }
 
 struct odb_packed_read_stream {

packfile.h

@@ -100,6 +100,9 @@ struct packfile_store {
 		unsigned flags;
 	} kept_cache;
 
+	/* The multi-pack index that belongs to this specific packfile store. */
+	struct multi_pack_index *midx;
+
 	/*
 	 * A map of packfile names to packed_git structs for tracking which
 	 * packs have been loaded already.