object-store: move alt_odb_list and alt_odb_tail to object store

In a process with multiple repositories open, alternates should be
associated to a single repository and not shared globally. Move
alt_odb_list and alt_odb_tail into the_repository and adjust callers
to reflect this.

Now that the alternative object data base is per repository, we're
leaking its memory upon freeing a repository. The next patch plugs
this hole.

No functional change intended.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fsck.c

@@ -1,5 +1,6 @@
 #include "builtin.h"
 #include "cache.h"
+#include "repository.h"
 #include "config.h"
 #include "commit.h"
 #include "tree.h"
@@ -714,9 +715,12 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 		for_each_loose_object(mark_loose_for_connectivity, NULL, 0);
 		for_each_packed_object(mark_packed_for_connectivity, NULL, 0);
 	} else {
+		struct alternate_object_database *alt_odb_list;
+
 		fsck_object_dir(get_object_directory());
 
 		prepare_alt_odb();
+		alt_odb_list = the_repository->objects->alt_odb_list;
 		for (alt = alt_odb_list; alt; alt = alt->next)
 			fsck_object_dir(alt->path);
 

object-store.h

@@ -1,7 +1,7 @@
 #ifndef OBJECT_STORE_H
 #define OBJECT_STORE_H
 
-extern struct alternate_object_database {
+struct alternate_object_database {
 	struct alternate_object_database *next;
 
 	/* see alt_scratch_buf() */
@@ -19,7 +19,7 @@ extern struct alternate_object_database {
 	struct oid_array loose_objects_cache;
 
 	char path[FLEX_ARRAY];
-} *alt_odb_list;
+};
 void prepare_alt_odb(void);
 char *compute_alternate_path(const char *path, struct strbuf *err);
 typedef int alt_odb_fn(struct alternate_object_database *, void *);
@@ -61,6 +61,9 @@ struct raw_object_store {
 
 	/* Path to extra alternate object database if not NULL */
 	char *alternate_db;
+
+	struct alternate_object_database *alt_odb_list;
+	struct alternate_object_database **alt_odb_tail;
 };
 
 struct raw_object_store *raw_object_store_new(void);

packfile.c

@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "list.h"
 #include "pack.h"
+#include "repository.h"
 #include "dir.h"
 #include "mergesort.h"
 #include "packfile.h"
@@ -892,7 +893,7 @@ void prepare_packed_git(void)
 		return;
 	prepare_packed_git_one(get_object_directory(), 1);
 	prepare_alt_odb();
-	for (alt = alt_odb_list; alt; alt = alt->next)
+	for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next)
 		prepare_packed_git_one(alt->path, 0);
 	rearrange_packed_git();
 	prepare_packed_git_mru();

sha1_file.c

@@ -22,6 +22,7 @@
 #include "pack-revindex.h"
 #include "sha1-lookup.h"
 #include "bulk-checkin.h"
+#include "repository.h"
 #include "streaming.h"
 #include "dir.h"
 #include "list.h"
@@ -343,9 +344,6 @@ static const char *alt_sha1_path(struct alternate_object_database *alt,
 	return buf->buf;
 }
 
-struct alternate_object_database *alt_odb_list;
-static struct alternate_object_database **alt_odb_tail;
-
 /*
  * Return non-zero iff the path is usable as an alternate object database.
  */
@@ -365,7 +363,7 @@ static int alt_odb_usable(struct strbuf *path, const char *normalized_objdir)
 	 * Prevent the common mistake of listing the same
 	 * thing twice, or object directory itself.
 	 */
-	for (alt = alt_odb_list; alt; alt = alt->next) {
+	for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next) {
 		if (!fspathcmp(path->buf, alt->path))
 			return 0;
 	}
@@ -425,8 +423,8 @@ static int link_alt_odb_entry(const char *entry, const char *relative_base,
 	ent = alloc_alt_odb(pathbuf.buf);
 
 	/* add the alternate entry */
-	*alt_odb_tail = ent;
-	alt_odb_tail = &(ent->next);
+	*the_repository->objects->alt_odb_tail = ent;
+	the_repository->objects->alt_odb_tail = &(ent->next);
 	ent->next = NULL;
 
 	/* recursively add alternates */
@@ -560,7 +558,7 @@ void add_to_alternates_file(const char *reference)
 		fprintf_or_die(out, "%s\n", reference);
 		if (commit_lock_file(&lock))
 			die_errno("unable to move new alternates file into place");
-		if (alt_odb_tail)
+		if (the_repository->objects->alt_odb_tail)
 			link_alt_odb_entries(reference, '\n', NULL, 0);
 	}
 	free(alts);
@@ -658,7 +656,7 @@ int foreach_alt_odb(alt_odb_fn fn, void *cb)
 	int r = 0;
 
 	prepare_alt_odb();
-	for (ent = alt_odb_list; ent; ent = ent->next) {
+	for (ent = the_repository->objects->alt_odb_list; ent; ent = ent->next) {
 		r = fn(ent, cb);
 		if (r)
 			break;
@@ -668,10 +666,11 @@ int foreach_alt_odb(alt_odb_fn fn, void *cb)
 
 void prepare_alt_odb(void)
 {
-	if (alt_odb_tail)
+	if (the_repository->objects->alt_odb_tail)
 		return;
 
-	alt_odb_tail = &alt_odb_list;
+	the_repository->objects->alt_odb_tail =
+			&the_repository->objects->alt_odb_list;
 	link_alt_odb_entries(the_repository->objects->alternate_db,
 			     PATH_SEP, NULL, 0);
 
@@ -716,7 +715,7 @@ static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 {
 	struct alternate_object_database *alt;
 	prepare_alt_odb();
-	for (alt = alt_odb_list; alt; alt = alt->next) {
+	for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next) {
 		const char *path = alt_sha1_path(alt, sha1);
 		if (check_and_freshen_file(path, freshen))
 			return 1;
@@ -876,7 +875,7 @@ static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
 
 	prepare_alt_odb();
 	errno = ENOENT;
-	for (alt = alt_odb_list; alt; alt = alt->next) {
+	for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next) {
 		*path = alt_sha1_path(alt, sha1);
 		if (!lstat(*path, st))
 			return 0;
@@ -906,7 +905,7 @@ static int open_sha1_file(const unsigned char *sha1, const char **path)
 	most_interesting_errno = errno;
 
 	prepare_alt_odb();
-	for (alt = alt_odb_list; alt; alt = alt->next) {
+	for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next) {
 		*path = alt_sha1_path(alt, sha1);
 		fd = git_open(*path);
 		if (fd >= 0)

sha1_name.c

@@ -11,6 +11,7 @@
 #include "sha1-array.h"
 #include "packfile.h"
 #include "object-store.h"
+#include "repository.h"
 
 static int get_oid_oneline(const char *, struct object_id *, struct commit_list *);
 
@@ -105,7 +106,7 @@ static void find_short_object_filename(struct disambiguate_state *ds)
 		 */
 		fakeent = alloc_alt_odb(get_object_directory());
 	}
-	fakeent->next = alt_odb_list;
+	fakeent->next = the_repository->objects->alt_odb_list;
 
 	for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 		int pos;