odb: move list of packfiles into struct packfile_store

The object database tracks the list of packfiles it currently knows
about. With the introduction of the `struct packfile_store` we have a
better place to host this list though.

Move the list accordingly. Extract the logic from `odb_clear()` that
knows to close all such packfiles and move it into the new subsystem, as
well.

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

odb.c

@@ -1038,16 +1038,8 @@ void odb_clear(struct object_database *o)
 
 	INIT_LIST_HEAD(&o->packed_git_mru);
 	close_object_store(o);
-
+	packfile_store_free(o->packfiles);
-	/*
+	o->packfiles = NULL;
-	 * `close_object_store()` only closes the packfiles, but doesn't free
-	 * them. We thus have to do this manually.
-	 */
-	for (struct packed_git *p = o->packed_git, *next; p; p = next) {
-		next = p->next;
-		free(p);
-	}
-	o->packed_git = NULL;
 
 	hashmap_clear(&o->pack_map);
 	string_list_clear(&o->submodule_source_paths, 0);

odb.h

@@ -138,7 +138,6 @@ struct object_database {
 	 * should only be accessed directly by packfile.c
 	 */
 	struct packfile_store *packfiles;
-	struct packed_git *packed_git;
 	/* A most-recently-used ordered version of the packed_git list. */
 	struct list_head packed_git_mru;
 

packfile.c

@@ -278,7 +278,7 @@ static int unuse_one_window(struct packed_git *current)
 
 	if (current)
 		scan_windows(current, &lru_p, &lru_w, &lru_l);
-	for (p = current->repo->objects->packed_git; p; p = p->next)
+	for (p = current->repo->objects->packfiles->packs; p; p = p->next)
 		scan_windows(p, &lru_p, &lru_w, &lru_l);
 	if (lru_p) {
 		munmap(lru_w->base, lru_w->len);
@@ -362,13 +362,8 @@ void close_pack(struct packed_git *p)
 void close_object_store(struct object_database *o)
 {
 	struct odb_source *source;
-	struct packed_git *p;
 
-	for (p = o->packed_git; p; p = p->next)
+	packfile_store_close(o->packfiles);
-		if (p->do_not_close)
-			BUG("want to close pack marked 'do-not-close'");
-		else
-			close_pack(p);
 
 	for (source = o->sources; source; source = source->next) {
 		if (source->midx)
@@ -468,7 +463,7 @@ static int close_one_pack(struct repository *r)
 	struct pack_window *mru_w = NULL;
 	int accept_windows_inuse = 1;
 
-	for (p = r->objects->packed_git; p; p = p->next) {
+	for (p = r->objects->packfiles->packs; p; p = p->next) {
 		if (p->pack_fd == -1)
 			continue;
 		find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
@@ -789,8 +784,8 @@ void install_packed_git(struct repository *r, struct packed_git *pack)
 	if (pack->pack_fd != -1)
 		pack_open_fds++;
 
-	pack->next = r->objects->packed_git;
+	pack->next = r->objects->packfiles->packs;
-	r->objects->packed_git = pack;
+	r->objects->packfiles->packs = pack;
 
 	hashmap_entry_init(&pack->packmap_ent, strhash(pack->pack_name));
 	hashmap_add(&r->objects->pack_map, &pack->packmap_ent);
@@ -974,7 +969,7 @@ unsigned long repo_approximate_object_count(struct repository *r)
 				count += m->num_objects;
 		}
 
-		for (p = r->objects->packed_git; p; p = p->next) {
+		for (p = r->objects->packfiles->packs; p; p = p->next) {
 			if (open_pack_index(p))
 				continue;
 			count += p->num_objects;
@@ -1015,7 +1010,7 @@ static int sort_pack(const struct packed_git *a, const struct packed_git *b)
 
 static void rearrange_packed_git(struct repository *r)
 {
-	sort_packs(&r->objects->packed_git, sort_pack);
+	sort_packs(&r->objects->packfiles->packs, sort_pack);
 }
 
 static void prepare_packed_git_mru(struct repository *r)
@@ -1024,7 +1019,7 @@ static void prepare_packed_git_mru(struct repository *r)
 
 	INIT_LIST_HEAD(&r->objects->packed_git_mru);
 
-	for (p = r->objects->packed_git; p; p = p->next)
+	for (p = r->objects->packfiles->packs; p; p = p->next)
 		list_add_tail(&p->mru, &r->objects->packed_git_mru);
 }
 
@@ -1073,7 +1068,7 @@ void reprepare_packed_git(struct repository *r)
 struct packed_git *get_packed_git(struct repository *r)
 {
 	prepare_packed_git(r);
-	return r->objects->packed_git;
+	return r->objects->packfiles->packs;
 }
 
 struct multi_pack_index *get_multi_pack_index(struct odb_source *source)
@@ -1094,7 +1089,7 @@ struct packed_git *get_all_packs(struct repository *r)
 			prepare_midx_pack(m, i);
 	}
 
-	return r->objects->packed_git;
+	return r->objects->packfiles->packs;
 }
 
 struct list_head *get_packed_git_mru(struct repository *r)
@@ -1219,7 +1214,7 @@ const struct packed_git *has_packed_and_bad(struct repository *r,
 {
 	struct packed_git *p;
 
-	for (p = r->objects->packed_git; p; p = p->next)
+	for (p = r->objects->packfiles->packs; p; p = p->next)
 		if (oidset_contains(&p->bad_objects, oid))
 			return p;
 	return NULL;
@@ -2080,7 +2075,7 @@ int find_pack_entry(struct repository *r, const struct object_id *oid, struct pa
 		if (source->midx && fill_midx_entry(source->midx, oid, e))
 			return 1;
 
-	if (!r->objects->packed_git)
+	if (!r->objects->packfiles->packs)
 		return 0;
 
 	list_for_each(pos, &r->objects->packed_git_mru) {
@@ -2343,5 +2338,18 @@ struct packfile_store *packfile_store_new(struct object_database *odb)
 
 void packfile_store_free(struct packfile_store *store)
 {
+	for (struct packed_git *p = store->packs, *next; p; p = next) {
+		next = p->next;
+		free(p);
+	}
 	free(store);
 }
+
+void packfile_store_close(struct packfile_store *store)
+{
+	for (struct packed_git *p = store->packs; p; p = p->next) {
+		if (p->do_not_close)
+			BUG("want to close pack marked 'do-not-close'");
+		close_pack(p);
+	}
+}

packfile.h

@@ -57,6 +57,12 @@ struct packed_git {
  */
 struct packfile_store {
 	struct object_database *odb;
+
+	/*
+	 * The list of packfiles in the order in which they are being added to
+	 * the store.
+	 */
+	struct packed_git *packs;
 };
 
 /*
@@ -66,10 +72,17 @@ struct packfile_store {
 struct packfile_store *packfile_store_new(struct object_database *odb);
 
 /*
- * Free the packfile store and all its associated state.
+ * Free the packfile store and all its associated state. All packfiles
+ * tracked by the store will be closed.
  */
 void packfile_store_free(struct packfile_store *store);
 
+/*
+ * Close all packfiles associated with this store. The packfiles won't be
+ * free'd, so they can be re-opened at a later point in time.
+ */
+void packfile_store_close(struct packfile_store *store);
+
 static inline int pack_map_entry_cmp(const void *cmp_data UNUSED,
 				     const struct hashmap_entry *entry,
 				     const struct hashmap_entry *entry2,