packfile: introduce function to load and add packfiles

We have a recurring pattern where we essentially perform an upsert of a
packfile in case it isn't yet known by the packfile store. The logic to
do so is non-trivial as we have to reconstruct the packfile's key, check
the map of packfiles, then create the new packfile and finally add it to
the store.

Introduce a new function that does this dance for us. Refactor callsites
to use it.

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

1 files changed, 8 insertions, 0 deletions

diff --git a/packfile.h b/packfile.h
index ba4b0cef9c..fcefcbbef6 100644
--- a/packfile.h
+++ b/packfile.h
@@ -127,6 +127,14 @@ void packfile_store_reprepare(struct packfile_store *store);
 void packfile_store_add_pack(struct packfile_store *store,
 			     struct packed_git *pack);
 
+/*
+ * 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;
 	unsigned char *base;