1 files changed, 139 insertions, 30 deletions

diff --git a/packfile.h b/packfile.h
index f16753f2a9..27ba607e7c 100644
--- a/packfile.h
+++ b/packfile.h
@@ -5,14 +5,12 @@
 #include "object.h"
 #include "odb.h"
 #include "oidset.h"
+#include "strmap.h"
 
 /* in odb.h */
 struct object_info;
 
 struct packed_git {
-	struct hashmap_entry packmap_ent;
-	struct packed_git *next;
-	struct list_head mru;
 	struct pack_window *windows;
 	off_t pack_size;
 	const void *index_data;
@@ -52,19 +50,146 @@ struct packed_git {
 	char pack_name[FLEX_ARRAY]; /* more */
 };
 
-static inline int pack_map_entry_cmp(const void *cmp_data UNUSED,
-				     const struct hashmap_entry *entry,
-				     const struct hashmap_entry *entry2,
-				     const void *keydata)
-{
-	const char *key = keydata;
-	const struct packed_git *pg1, *pg2;
+struct packfile_list {
+	struct packfile_list_entry *head, *tail;
+};
+
+struct packfile_list_entry {
+	struct packfile_list_entry *next;
+	struct packed_git *pack;
+};
+
+void packfile_list_clear(struct packfile_list *list);
+void packfile_list_remove(struct packfile_list *list, struct packed_git *pack);
+void packfile_list_prepend(struct packfile_list *list, struct packed_git *pack);
+void packfile_list_append(struct packfile_list *list, struct packed_git *pack);
+
+/*
+ * Find the pack within the "packs" list whose index contains the object
+ * "oid". For general object lookups, you probably don't want this; use
+ * find_pack_entry() instead.
+ */
+struct packed_git *packfile_list_find_oid(struct packfile_list_entry *packs,
+					  const struct object_id *oid);
+
+/*
+ * A store that manages packfiles for a given object database.
+ */
+struct packfile_store {
+	struct object_database *odb;
+
+	/*
+	 * The list of packfiles in the order in which they have been most
+	 * recently used.
+	 */
+	struct packfile_list 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 map of packfile names to packed_git structs for tracking which
+	 * packs have been loaded already.
+	 */
+	struct strmap packs_by_path;
+
+	/*
+	 * Whether packfiles have already been populated with this store's
+	 * packs.
+	 */
+	bool initialized;
+
+	/*
+	 * Usually, packfiles will be reordered to the front of the `packs`
+	 * list whenever an object is looked up via them. This has the effect
+	 * that packs that contain a lot of accessed objects will be located
+	 * towards the front.
+	 *
+	 * This is usually desireable, but there are exceptions. One exception
+	 * is when the looking up multiple objects in a loop for each packfile.
+	 * In that case, we may easily end up with an infinite loop as the
+	 * packfiles get reordered to the front repeatedly.
+	 *
+	 * Setting this field to `true` thus disables these reorderings.
+	 */
+	bool skip_mru_updates;
+};
+
+/*
+ * Allocate and initialize a new empty packfile store for the given object
+ * database.
+ */
+struct packfile_store *packfile_store_new(struct object_database *odb);
 
-	pg1 = container_of(entry, const struct packed_git, packmap_ent);
-	pg2 = container_of(entry2, const struct packed_git, packmap_ent);
+/*
+ * 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);
+
+/*
+ * Prepare the packfile store by loading packfiles and multi-pack indices for
+ * all alternates. This becomes a no-op if the store is already prepared.
+ *
+ * It shouldn't typically be necessary to call this function directly, as
+ * functions that access the store know to prepare it.
+ */
+void packfile_store_prepare(struct packfile_store *store);
+
+/*
+ * Clear the packfile caches and try to look up any new packfiles that have
+ * appeared since last preparing the packfiles store.
+ *
+ * This function must be called under the `odb_read_lock()`.
+ */
+void packfile_store_reprepare(struct packfile_store *store);
+
+/*
+ * Add the pack to the store so that contained objects become accessible via
+ * the store. This moves ownership into the store.
+ */
+void packfile_store_add_pack(struct packfile_store *store,
+			     struct packed_git *pack);
+
+/*
+ * Load and iterate through all packs of the given repository. This helper
+ * function will yield packfiles from all object sources connected to the
+ * repository.
+ */
+#define repo_for_each_pack(repo, p) \
+	for (struct packfile_list_entry *e = packfile_store_get_packs(repo->objects->packfiles); \
+	     ((p) = (e ? e->pack : NULL)); e = e->next)
 
-	return strcmp(pg1->pack_name, key ? key : pg2->pack_name);
-}
+/*
+ * Get all packs managed by the given store, including packfiles that are
+ * referenced by multi-pack indices.
+ */
+struct packfile_list_entry *packfile_store_get_packs(struct packfile_store *store);
+
+/*
+ * Open the packfile and add it to the store if it isn't yet known. Returns
+ * either the newly opened packfile or the preexisting packfile. Returns a
+ * `NULL` pointer in case the packfile could not be opened.
+ */
+struct packed_git *packfile_store_load_pack(struct packfile_store *store,
+					    const char *idx_path, int local);
 
 struct pack_window {
 	struct pack_window *next;
@@ -142,28 +267,12 @@ int for_each_packed_object(struct repository *repo, each_packed_object_fn cb,
 #define PACKDIR_FILE_GARBAGE 4
 extern void (*report_garbage)(unsigned seen_bits, const char *path);
 
-void reprepare_packed_git(struct repository *r);
-void install_packed_git(struct repository *r, struct packed_git *pack);
-
-struct packed_git *get_packed_git(struct repository *r);
-struct list_head *get_packed_git_mru(struct repository *r);
-struct multi_pack_index *get_multi_pack_index(struct odb_source *source);
-struct packed_git *get_all_packs(struct repository *r);
-
 /*
  * Give a rough count of objects in the repository. This sacrifices accuracy
  * for speed.
  */
 unsigned long repo_approximate_object_count(struct repository *r);
 
-/*
- * Find the pack within the "packs" list whose index contains the object "oid".
- * For general object lookups, you probably don't want this; use
- * find_pack_entry() instead.
- */
-struct packed_git *find_oid_pack(const struct object_id *oid,
-				 struct packed_git *packs);
-
 void pack_report(struct repository *repo);
 
 /*