repository: introduce parsed objects field

Convert the existing global cache for parsed objects (obj_hash) into
repository-specific parsed object caches. Existing code that uses
obj_hash are modified to use the parsed object cache of
the_repository; future patches will use the parsed object caches of
other repositories.

Another future use case for a pool of objects is ease of memory management
in revision walking: If we can free the rev-list related memory early in
pack-objects (e.g. part of repack operation) then it could lower memory
pressure significantly when running on large repos. While this has been
discussed on the mailing list lately, this series doesn't implement this.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/repository.h b/repository.h
index e6e00f541b..6d19981990 100644
--- a/repository.h
+++ b/repository.h
@@ -26,6 +26,15 @@ struct repository {
 	 */
 	struct raw_object_store *objects;
 
+	/*
+	 * All objects in this repository that have been parsed. This structure
+	 * owns all objects it references, so users of "struct object *"
+	 * generally do not need to free them; instead, when a repository is no
+	 * longer used, call parsed_object_pool_clear() on this structure, which
+	 * is called by the repositories repo_clear on its desconstruction.
+	 */
+	struct parsed_object_pool *parsed_objects;
+
 	/* The store in which the refs are held. */
 	struct ref_store *refs;