[PATCH v2 8/9] object-store: remove global array of cached objects

[Patrick Steinhardt <ps@pks.im>]

Cached objects are virtual objects that can be set up without writing
anything into the object store directly. This mechanism for example
allows us to create fake commits in git-blame(1).

The cached objects are stored in a global variable. Refactor the code so
that we instead store the array as part of the raw object store. This is
another step into the direction of libifying our object database.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 blame.c           |  2 +-
 object-store-ll.h | 14 +++++++++++++-
 object-store.c    | 39 +++++++++++++++++++++++----------------
 3 files changed, 37 insertions(+), 18 deletions(-)

diff --git a/blame.c b/blame.c
index 703dab43e78..b7c5bd692e6 100644
--- a/blame.c
+++ b/blame.c
@@ -277,7 +277,7 @@ static struct commit *fake_working_tree_commit(struct repository *r,
 	convert_to_git(r->index, path, buf.buf, buf.len, &buf, 0);
 	origin->file.ptr = buf.buf;
 	origin->file.size = buf.len;
-	pretend_object_file(buf.buf, buf.len, OBJ_BLOB, &origin->blob_oid);
+	pretend_object_file(the_repository, buf.buf, buf.len, OBJ_BLOB, &origin->blob_oid);
 
 	/*
 	 * Read the current index, replace the path entry with
diff --git a/object-store-ll.h b/object-store-ll.h
index 8bb0f33f9a8..bb5e8798a1b 100644
--- a/object-store-ll.h
+++ b/object-store-ll.h
@@ -151,6 +151,8 @@ static inline int pack_map_entry_cmp(const void *cmp_data UNUSED,
 	return strcmp(pg1->pack_name, key ? key : pg2->pack_name);
 }
 
+struct cached_object_entry;
+
 struct raw_object_store {
 	/*
 	 * Set of all object directories; the main directory is first (and
@@ -203,6 +205,15 @@ struct raw_object_store {
 		unsigned flags;
 	} kept_pack_cache;
 
+	/*
+	 * This is meant to hold a *small* number of objects that you would
+	 * want repo_read_object_file() to be able to return, but yet you do not want
+	 * to write them into the object store (e.g. a browse-only
+	 * application).
+	 */
+	struct cached_object_entry *cached_objects;
+	size_t cached_object_nr, cached_object_alloc;
+
 	/*
 	 * A map of packfiles to packed_git structs for tracking which
 	 * packs have been loaded already.
@@ -272,7 +283,8 @@ void hash_object_file(const struct git_hash_algo *algo, const void *buf,
  * object in persistent storage before writing any other new objects
  * that reference it.
  */
-int pretend_object_file(void *, unsigned long, enum object_type,
+int pretend_object_file(struct repository *repo,
+			void *buf, unsigned long len, enum object_type type,
 			struct object_id *oid);
 
 struct object_info {
diff --git a/object-store.c b/object-store.c
index ea2d86c429b..17fa06a86fa 100644
--- a/object-store.c
+++ b/object-store.c
@@ -30,31 +30,31 @@
  * to write them into the object store (e.g. a browse-only
  * application).
  */
-static struct cached_object_entry {
+struct cached_object_entry {
 	struct object_id oid;
 	struct cached_object {
 		enum object_type type;
 		const void *buf;
 		unsigned long size;
 	} value;
-} *cached_objects;
-static int cached_object_nr, cached_object_alloc;
+};
 
-static const struct cached_object *find_cached_object(const struct object_id *oid)
+static const struct cached_object *find_cached_object(struct raw_object_store *object_store,
+						      const struct object_id *oid)
 {
 	static const struct cached_object empty_tree = {
 		.type = OBJ_TREE,
 		.buf = "",
 	};
-	int i;
-	const struct cached_object_entry *co = cached_objects;
+	const struct cached_object_entry *co = object_store->cached_objects;
 
-	for (i = 0; i < cached_object_nr; i++, co++) {
+	for (size_t i = 0; i < object_store->cached_object_nr; i++, co++)
 		if (oideq(&co->oid, oid))
 			return &co->value;
-	}
-	if (oideq(oid, the_hash_algo->empty_tree))
+
+	if (oid->algo && oideq(oid, hash_algos[oid->algo].empty_tree))
 		return &empty_tree;
+
 	return NULL;
 }
 
@@ -650,7 +650,7 @@ static int do_oid_object_info_extended(struct repository *r,
 	if (!oi)
 		oi = &blank_oi;
 
-	co = find_cached_object(real);
+	co = find_cached_object(r->objects, real);
 	if (co) {
 		if (oi->typep)
 			*(oi->typep) = co->type;
@@ -853,18 +853,21 @@ int oid_object_info(struct repository *r,
 	return type;
 }
 
-int pretend_object_file(void *buf, unsigned long len, enum object_type type,
+int pretend_object_file(struct repository *repo,
+			void *buf, unsigned long len, enum object_type type,
 			struct object_id *oid)
 {
 	struct cached_object_entry *co;
 	char *co_buf;
 
-	hash_object_file(the_hash_algo, buf, len, type, oid);
-	if (repo_has_object_file_with_flags(the_repository, oid, OBJECT_INFO_QUICK | OBJECT_INFO_SKIP_FETCH_OBJECT) ||
-	    find_cached_object(oid))
+	hash_object_file(repo->hash_algo, buf, len, type, oid);
+	if (repo_has_object_file_with_flags(repo, oid, OBJECT_INFO_QUICK | OBJECT_INFO_SKIP_FETCH_OBJECT) ||
+	    find_cached_object(repo->objects, oid))
 		return 0;
-	ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
-	co = &cached_objects[cached_object_nr++];
+
+	ALLOC_GROW(repo->objects->cached_objects,
+		   repo->objects->cached_object_nr + 1, repo->objects->cached_object_alloc);
+	co = &repo->objects->cached_objects[repo->objects->cached_object_nr++];
 	co->value.size = len;
 	co->value.type = type;
 	co_buf = xmalloc(len);
@@ -1021,6 +1024,10 @@ void raw_object_store_clear(struct raw_object_store *o)
 	o->odb_tail = NULL;
 	o->loaded_alternates = 0;
 
+	for (size_t i = 0; i < o->cached_object_nr; i++)
+		free((char *) o->cached_objects[i].value.buf);
+	FREE_AND_NULL(o->cached_objects);
+
 	INIT_LIST_HEAD(&o->packed_git_mru);
 	close_object_store(o);
 

-- 
2.49.0.777.g153de2bbd5.dirty