[PATCH 6/9] packfile: add all_packs list

[Derrick Stolee <dstolee@microsoft.com>]

If a repo contains a multi-pack-index, then the packed_git list
does not contain the packfiles that are covered by the multi-pack-index.
This is important for doing object lookups, abbreviations, and
approximating object count. However, there are many operations that
really want to iterate over all packfiles.

Create a new 'all_packs' linked list that contains this list, starting
with the packfiles in the multi-pack-index and then continuing along
the packed_git linked list.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 midx.c         |  2 +-
 midx.h         |  1 +
 object-store.h |  6 ++++++
 packfile.c     | 27 +++++++++++++++++++++++++++
 packfile.h     |  1 +
 5 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/midx.c b/midx.c
index 0710c4c175..f3e8dbc108 100644
--- a/midx.c
+++ b/midx.c
@@ -197,7 +197,7 @@ static void close_midx(struct multi_pack_index *m)
 	FREE_AND_NULL(m->pack_names);
 }
 
-static int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id)
+int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id)
 {
 	struct strbuf pack_name = STRBUF_INIT;
 
diff --git a/midx.h b/midx.h
index 8aa79f4b62..a210f1af2a 100644
--- a/midx.h
+++ b/midx.h
@@ -32,6 +32,7 @@ struct multi_pack_index {
 };
 
 struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local);
+int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id);
 int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result);
 struct object_id *nth_midxed_object_oid(struct object_id *oid,
 					struct multi_pack_index *m,
diff --git a/object-store.h b/object-store.h
index f9c57e2c26..c69d546392 100644
--- a/object-store.h
+++ b/object-store.h
@@ -128,6 +128,12 @@ struct raw_object_store {
 	/* A most-recently-used ordered version of the packed_git list. */
 	struct list_head packed_git_mru;
 
+	/*
+	 * A linked list containing all packfiles, starting with those
+	 * contained in the multi_pack_index.
+	 */
+	struct packed_git *all_packs;
+
 	/*
 	 * A fast, rough count of the number of objects in the repository.
 	 * These two fields are not meant for direct access. Use
diff --git a/packfile.c b/packfile.c
index fe713a0242..adcf2e12a0 100644
--- a/packfile.c
+++ b/packfile.c
@@ -972,6 +972,9 @@ static void prepare_packed_git(struct repository *r)
 		prepare_packed_git_one(r, alt->path, 0);
 	}
 	rearrange_packed_git(r);
+
+	r->objects->all_packs = NULL;
+
 	prepare_packed_git_mru(r);
 	r->objects->packed_git_initialized = 1;
 }
@@ -995,6 +998,30 @@ struct multi_pack_index *get_multi_pack_index(struct repository *r)
 	return r->objects->multi_pack_index;
 }
 
+struct packed_git *get_all_packs(struct repository *r)
+{
+	prepare_packed_git(r);
+
+	if (!r->objects->all_packs) {
+		struct packed_git *p = r->objects->packed_git;
+		struct multi_pack_index *m;
+
+		for (m = r->objects->multi_pack_index; m; m = m->next) {
+			uint32_t i;
+			for (i = 0; i < m->num_packs; i++) {
+				if (!prepare_midx_pack(m, i)) {
+					m->packs[i]->next = p;
+					p = m->packs[i];
+				}
+			}
+		}
+
+		r->objects->all_packs = p;
+	}
+
+	return r->objects->all_packs;
+}
+
 struct list_head *get_packed_git_mru(struct repository *r)
 {
 	prepare_packed_git(r);
diff --git a/packfile.h b/packfile.h
index 7855556686..3b90e2864c 100644
--- a/packfile.h
+++ b/packfile.h
@@ -51,6 +51,7 @@ extern 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 repository *r);
+struct packed_git *get_all_packs(struct repository *r);
 
 /*
  * Give a rough count of objects in the repository. This sacrifices accuracy
-- 
2.18.0.118.gd4f65b8d14