Merge branch 'sb/object-store'

Refactoring the internal global data structure to make it possible
to open multiple repositories, work with and then close them.

Rerolled by Duy on top of a separate preliminary clean-up topic.
The resulting structure of the topics looked very sensible.

* sb/object-store: (27 commits)
  sha1_file: allow sha1_loose_object_info to handle arbitrary repositories
  sha1_file: allow map_sha1_file to handle arbitrary repositories
  sha1_file: allow map_sha1_file_1 to handle arbitrary repositories
  sha1_file: allow open_sha1_file to handle arbitrary repositories
  sha1_file: allow stat_sha1_file to handle arbitrary repositories
  sha1_file: allow sha1_file_name to handle arbitrary repositories
  sha1_file: add repository argument to sha1_loose_object_info
  sha1_file: add repository argument to map_sha1_file
  sha1_file: add repository argument to map_sha1_file_1
  sha1_file: add repository argument to open_sha1_file
  sha1_file: add repository argument to stat_sha1_file
  sha1_file: add repository argument to sha1_file_name
  sha1_file: allow prepare_alt_odb to handle arbitrary repositories
  sha1_file: allow link_alt_odb_entries to handle arbitrary repositories
  sha1_file: add repository argument to prepare_alt_odb
  sha1_file: add repository argument to link_alt_odb_entries
  sha1_file: add repository argument to read_info_alternates
  sha1_file: add repository argument to link_alt_odb_entry
  sha1_file: add raw_object_store argument to alt_odb_usable
  pack: move approximate object count to object store
  ...

39 files changed, 393 insertions, 233 deletions

diff --git a/builtin/am.c b/builtin/am.c
index 1bcc3606c5..9c82603f70 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1862,7 +1862,7 @@ next:
 	 */
 	if (!state->rebasing) {
 		am_destroy(state);
-		close_all_packs();
+		close_all_packs(the_repository->objects);
 		run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 	}
 }
diff --git a/builtin/clone.c b/builtin/clone.c
index 101c27a593..7df5932b85 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -27,6 +27,7 @@
 #include "connected.h"
 #include "packfile.h"
 #include "list-objects-filter-options.h"
+#include "object-store.h"
 
 /*
  * Overall FIXMEs:
@@ -1217,7 +1218,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	transport_disconnect(transport);
 
 	if (option_dissociate) {
-		close_all_packs();
+		close_all_packs(the_repository->objects);
 		dissociate_from_references();
 	}
 
diff --git a/builtin/count-objects.c b/builtin/count-objects.c
index 33343818c8..b28ff00be2 100644
--- a/builtin/count-objects.c
+++ b/builtin/count-objects.c
@@ -7,10 +7,12 @@
 #include "cache.h"
 #include "config.h"
 #include "dir.h"
+#include "repository.h"
 #include "builtin.h"
 #include "parse-options.h"
 #include "quote.h"
 #include "packfile.h"
+#include "object-store.h"
 
 static unsigned long garbage;
 static off_t size_garbage;
@@ -120,9 +122,9 @@ int cmd_count_objects(int argc, const char **argv, const char *prefix)
 		struct strbuf loose_buf = STRBUF_INIT;
 		struct strbuf pack_buf = STRBUF_INIT;
 		struct strbuf garbage_buf = STRBUF_INIT;
-		if (!packed_git)
+		if (!get_packed_git(the_repository))
 			prepare_packed_git();
-		for (p = packed_git; p; p = p->next) {
+		for (p = get_packed_git(the_repository); p; p = p->next) {
 			if (!p->pack_local)
 				continue;
 			if (open_pack_index(p))
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 8295f92b3e..dcdfc66f09 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1516,7 +1516,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 
 	string_list_clear(&list, 0);
 
-	close_all_packs();
+	close_all_packs(the_repository->objects);
 
 	argv_array_pushl(&argv_gc_auto, "gc", "--auto", NULL);
 	if (verbosity < 0)
diff --git a/builtin/fsck.c b/builtin/fsck.c
index 0922558683..13c0a8048e 100644
--- a/builtin/fsck.c
+++ b/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"
@@ -16,6 +17,7 @@
 #include "streaming.h"
 #include "decorate.h"
 #include "packfile.h"
+#include "object-store.h"
 
 #define REACHABLE 0x0001
 #define SEEN      0x0002
@@ -719,9 +721,12 @@ 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();
+		prepare_alt_odb(the_repository);
+		alt_odb_list = the_repository->objects->alt_odb_list;
 		for (alt = alt_odb_list; alt; alt = alt->next)
 			fsck_object_dir(alt->path);
 
@@ -733,7 +738,8 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 			prepare_packed_git();
 
 			if (show_progress) {
-				for (p = packed_git; p; p = p->next) {
+				for (p = get_packed_git(the_repository); p;
+				     p = p->next) {
 					if (open_pack_index(p))
 						continue;
 					total += p->num_objects;
@@ -741,7 +747,8 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 
 				progress = start_progress(_("Checking objects"), total);
 			}
-			for (p = packed_git; p; p = p->next) {
+			for (p = get_packed_git(the_repository); p;
+			     p = p->next) {
 				/* verify gives error messages itself */
 				if (verify_pack(p, fsck_obj_buffer,
 						progress, count))
diff --git a/builtin/gc.c b/builtin/gc.c
index f51e5a6500..cef38e5427 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -11,6 +11,7 @@
  */
 
 #include "builtin.h"
+#include "repository.h"
 #include "config.h"
 #include "tempfile.h"
 #include "lockfile.h"
@@ -20,6 +21,7 @@
 #include "argv-array.h"
 #include "commit.h"
 #include "packfile.h"
+#include "object-store.h"
 
 #define FAILED_RUN "failed to run %s"
 
@@ -173,7 +175,7 @@ static int too_many_packs(void)
 		return 0;
 
 	prepare_packed_git();
-	for (cnt = 0, p = packed_git; p; p = p->next) {
+	for (cnt = 0, p = get_packed_git(the_repository); p; p = p->next) {
 		if (!p->pack_local)
 			continue;
 		if (p->pack_keep)
diff --git a/builtin/grep.c b/builtin/grep.c
index 668cb8050a..5f32d2ce84 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -22,6 +22,7 @@
 #include "pathspec.h"
 #include "submodule.h"
 #include "submodule-config.h"
+#include "object-store.h"
 
 static char const * const grep_usage[] = {
 	N_("git grep [<options>] [-e] <pattern> [<rev>...] [[--] <path>...]"),
@@ -439,7 +440,7 @@ static int grep_submodule(struct grep_opt *opt, struct repository *superproject,
 	 * object.
 	 */
 	grep_read_lock();
-	add_to_alternates_memory(submodule.objectdir);
+	add_to_alternates_memory(submodule.objects->objectdir);
 	grep_read_unlock();
 
 	if (oid) {
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 657a5dda06..d81473e722 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -13,6 +13,7 @@
 #include "streaming.h"
 #include "thread-utils.h"
 #include "packfile.h"
+#include "object-store.h"
 
 static const char index_pack_usage[] =
 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
diff --git a/builtin/merge.c b/builtin/merge.c
index 8746c5e3e8..9db5a2cf16 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -412,7 +412,7 @@ static void finish(struct commit *head_commit,
 			 * We ignore errors in 'gc --auto', since the
 			 * user should see them.
 			 */
-			close_all_packs();
+			close_all_packs(the_repository->objects);
 			run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 		}
 	}
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index e7e673266e..89f49bb5f6 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1,5 +1,6 @@
 #include "builtin.h"
 #include "cache.h"
+#include "repository.h"
 #include "config.h"
 #include "attr.h"
 #include "object.h"
@@ -28,6 +29,7 @@
 #include "argv-array.h"
 #include "list.h"
 #include "packfile.h"
+#include "object-store.h"
 
 static const char *pack_usage[] = {
 	N_("git pack-objects --stdout [<options>...] [< <ref-list> | < <object-list>]"),
@@ -1023,8 +1025,7 @@ static int want_object_in_pack(const struct object_id *oid,
 		if (want != -1)
 			return want;
 	}
-
-	list_for_each(pos, &packed_git_mru) {
+	list_for_each(pos, get_packed_git_mru(the_repository)) {
 		struct packed_git *p = list_entry(pos, struct packed_git, mru);
 		off_t offset;
 
@@ -1042,7 +1043,8 @@ static int want_object_in_pack(const struct object_id *oid,
 			}
 			want = want_found_object(exclude, p);
 			if (!exclude && want > 0)
-				list_move(&p->mru, &packed_git_mru);
+				list_move(&p->mru,
+					  get_packed_git_mru(the_repository));
 			if (want != -1)
 				return want;
 		}
@@ -2669,7 +2671,7 @@ static void add_objects_in_unpacked_packs(struct rev_info *revs)
 
 	memset(&in_pack, 0, sizeof(in_pack));
 
-	for (p = packed_git; p; p = p->next) {
+	for (p = get_packed_git(the_repository); p; p = p->next) {
 		struct object_id oid;
 		struct object *o;
 
@@ -2732,7 +2734,8 @@ static int has_sha1_pack_kept_or_nonlocal(const struct object_id *oid)
 	static struct packed_git *last_found = (void *)1;
 	struct packed_git *p;
 
-	p = (last_found != (void *)1) ? last_found : packed_git;
+	p = (last_found != (void *)1) ? last_found :
+					get_packed_git(the_repository);
 
 	while (p) {
 		if ((!p->pack_local || p->pack_keep) &&
@@ -2741,7 +2744,7 @@ static int has_sha1_pack_kept_or_nonlocal(const struct object_id *oid)
 			return 1;
 		}
 		if (p == last_found)
-			p = packed_git;
+			p = get_packed_git(the_repository);
 		else
 			p = p->next;
 		if (p == last_found)
@@ -2777,7 +2780,7 @@ static void loosen_unused_packed_objects(struct rev_info *revs)
 	uint32_t i;
 	struct object_id oid;
 
-	for (p = packed_git; p; p = p->next) {
+	for (p = get_packed_git(the_repository); p; p = p->next) {
 		if (!p->pack_local || p->pack_keep)
 			continue;
 
@@ -3148,7 +3151,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 	prepare_packed_git();
 	if (ignore_packed_keep) {
 		struct packed_git *p;
-		for (p = packed_git; p; p = p->next)
+		for (p = get_packed_git(the_repository); p; p = p->next)
 			if (p->pack_local && p->pack_keep)
 				break;
 		if (!p) /* no keep-able packs found */
@@ -3161,7 +3164,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 		 * also covers non-local objects
 		 */
 		struct packed_git *p;
-		for (p = packed_git; p; p = p->next) {
+		for (p = get_packed_git(the_repository); p; p = p->next) {
 			if (!p->pack_local) {
 				have_non_local_packs = 1;
 				break;
diff --git a/builtin/pack-redundant.c b/builtin/pack-redundant.c
index 991e1bb76f..f060b941b5 100644
--- a/builtin/pack-redundant.c
+++ b/builtin/pack-redundant.c
@@ -7,7 +7,9 @@
 */
 
 #include "builtin.h"
+#include "repository.h"
 #include "packfile.h"
+#include "object-store.h"
 
 #define BLKSIZE 512
 
@@ -571,7 +573,7 @@ static struct pack_list * add_pack(struct packed_git *p)
 
 static struct pack_list * add_pack_file(const char *filename)
 {
-	struct packed_git *p = packed_git;
+	struct packed_git *p = get_packed_git(the_repository);
 
 	if (strlen(filename) < 40)
 		die("Bad pack filename: %s", filename);
@@ -586,7 +588,7 @@ static struct pack_list * add_pack_file(const char *filename)
 
 static void load_all(void)
 {
-	struct packed_git *p = packed_git;
+	struct packed_git *p = get_packed_git(the_repository);
 
 	while (p) {
 		add_pack(p);
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 2bf7f2d1a3..19428ef97d 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -2027,7 +2027,7 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 			proc.git_cmd = 1;
 			proc.argv = argv_gc_auto;
 
-			close_all_packs();
+			close_all_packs(the_repository->objects);
 			if (!start_command(&proc)) {
 				if (use_sideband)
 					copy_to_sideband(proc.err, -1, NULL);
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 6ba8587b6d..a2327c98b0 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -16,6 +16,7 @@
 #include "revision.h"
 #include "diffcore.h"
 #include "diff.h"
+#include "object-store.h"
 
 #define OPT_QUIET (1 << 0)
 #define OPT_CACHED (1 << 1)
diff --git a/cache.h b/cache.h
index 6e45c1b537..bbaf5c349a 100644
--- a/cache.h
+++ b/cache.h
@@ -941,12 +941,6 @@ extern void check_repository_format(void);
 #define TYPE_CHANGED    0x0040
 
 /*
- * Put in `buf` the name of the file in the local object database that
- * would be used to store a loose object with the specified sha1.
- */
-extern void sha1_file_name(struct strbuf *buf, const unsigned char *sha1);
-
-/*
  * Return an abbreviated sha1 unique within this repository's object database.
  * The result will be at least `len` characters long, and will be NUL
  * terminated.
@@ -1236,7 +1230,6 @@ extern int force_object_loose(const struct object_id *oid, time_t mtime);
 
 extern int git_open_cloexec(const char *name, int flags);
 #define git_open(name) git_open_cloexec(name, O_RDONLY)
-extern void *map_sha1_file(const unsigned char *sha1, unsigned long *size);
 extern int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz);
 extern int parse_sha1_header(const char *hdr, unsigned long *sizep);
 
@@ -1564,57 +1557,6 @@ extern int has_dirs_only_path(const char *name, int len, int prefix_len);
 extern void schedule_dir_for_removal(const char *name, int len);
 extern void remove_scheduled_dirs(void);
 
-extern struct alternate_object_database {
-	struct alternate_object_database *next;
-
-	/* see alt_scratch_buf() */
-	struct strbuf scratch;
-	size_t base_len;
-
-	/*
-	 * Used to store the results of readdir(3) calls when searching
-	 * for unique abbreviated hashes.  This cache is never
-	 * invalidated, thus it's racy and not necessarily accurate.
-	 * That's fine for its purpose; don't use it for tasks requiring
-	 * greater accuracy!
-	 */
-	char loose_objects_subdir_seen[256];
-	struct oid_array loose_objects_cache;
-
-	char path[FLEX_ARRAY];
-} *alt_odb_list;
-extern void prepare_alt_odb(void);
-extern char *compute_alternate_path(const char *path, struct strbuf *err);
-typedef int alt_odb_fn(struct alternate_object_database *, void *);
-extern int foreach_alt_odb(alt_odb_fn, void*);
-
-/*
- * Allocate a "struct alternate_object_database" but do _not_ actually
- * add it to the list of alternates.
- */
-struct alternate_object_database *alloc_alt_odb(const char *dir);
-
-/*
- * Add the directory to the on-disk alternates file; the new entry will also
- * take effect in the current process.
- */
-extern void add_to_alternates_file(const char *dir);
-
-/*
- * Add the directory to the in-memory list of alternates (along with any
- * recursive alternates it points to), but do not modify the on-disk alternates
- * file.
- */
-extern void add_to_alternates_memory(const char *dir);
-
-/*
- * Returns a scratch strbuf pre-filled with the alternate object directory,
- * including a trailing slash, which can be used to access paths in the
- * alternate. Always use this over direct access to alt->scratch, as it
- * cleans up any previous use of the scratch buffer.
- */
-extern struct strbuf *alt_scratch_buf(struct alternate_object_database *alt);
-
 struct pack_window {
 	struct pack_window *next;
 	unsigned char *base;
@@ -1624,35 +1566,6 @@ struct pack_window {
 	unsigned int inuse_cnt;
 };
 
-extern struct packed_git {
-	struct packed_git *next;
-	struct list_head mru;
-	struct pack_window *windows;
-	off_t pack_size;
-	const void *index_data;
-	size_t index_size;
-	uint32_t num_objects;
-	uint32_t num_bad_objects;
-	unsigned char *bad_object_sha1;
-	int index_version;
-	time_t mtime;
-	int pack_fd;
-	unsigned pack_local:1,
-		 pack_keep:1,
-		 freshened:1,
-		 do_not_close:1,
-		 pack_promisor:1;
-	unsigned char sha1[20];
-	struct revindex_entry *revindex;
-	/* something like ".git/objects/pack/xxxxx.pack" */
-	char pack_name[FLEX_ARRAY]; /* more */
-} *packed_git;
-
-/*
- * A most-recently-used ordered version of the packed_git list.
- */
-extern struct list_head packed_git_mru;
-
 struct pack_entry {
 	off_t offset;
 	unsigned char sha1[20];
diff --git a/environment.c b/environment.c
index 21565c3c52..39b3d906c8 100644
--- a/environment.c
+++ b/environment.c
@@ -14,6 +14,7 @@
 #include "fmt-merge-msg.h"
 #include "commit.h"
 #include "argv-array.h"
+#include "object-store.h"
 
 int trust_executable_bit = 1;
 int trust_ctime = 1;
@@ -270,9 +271,9 @@ const char *get_git_work_tree(void)
 
 char *get_object_directory(void)
 {
-	if (!the_repository->objectdir)
+	if (!the_repository->objects->objectdir)
 		BUG("git environment hasn't been setup");
-	return the_repository->objectdir;
+	return the_repository->objects->objectdir;
 }
 
 int odb_mkstemp(struct strbuf *temp_filename, const char *pattern)
diff --git a/fast-import.c b/fast-import.c
index a2e8b1d763..b2f6d6d583 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -154,6 +154,7 @@ Format of STDIN stream:
 
 #include "builtin.h"
 #include "cache.h"
+#include "repository.h"
 #include "config.h"
 #include "lockfile.h"
 #include "object.h"
@@ -168,6 +169,7 @@ Format of STDIN stream:
 #include "dir.h"
 #include "run-command.h"
 #include "packfile.h"
+#include "object-store.h"
 
 #define PACK_ID_BITS 16
 #define MAX_PACK_ID ((1<<PACK_ID_BITS)-1)
@@ -1110,7 +1112,8 @@ static int store_object(
 	if (e->idx.offset) {
 		duplicate_count_by_type[type]++;
 		return 1;
-	} else if (find_sha1_pack(oid.hash, packed_git)) {
+	} else if (find_sha1_pack(oid.hash,
+				  get_packed_git(the_repository))) {
 		e->type = type;
 		e->pack_id = MAX_PACK_ID;
 		e->idx.offset = 1; /* just not zero! */
@@ -1307,7 +1310,8 @@ static void stream_blob(uintmax_t len, struct object_id *oidout, uintmax_t mark)
 		duplicate_count_by_type[OBJ_BLOB]++;
 		truncate_pack(&checkpoint);
 
-	} else if (find_sha1_pack(oid.hash, packed_git)) {
+	} else if (find_sha1_pack(oid.hash,
+				  get_packed_git(the_repository))) {
 		e->type = OBJ_BLOB;
 		e->pack_id = MAX_PACK_ID;
 		e->idx.offset = 1; /* just not zero! */
diff --git a/http-backend.c b/http-backend.c
index f3dc218b2a..64dde78c1b 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "config.h"
+#include "repository.h"
 #include "refs.h"
 #include "pkt-line.h"
 #include "object.h"
@@ -10,6 +11,7 @@
 #include "url.h"
 #include "argv-array.h"
 #include "packfile.h"
+#include "object-store.h"
 
 static const char content_type[] = "Content-Type";
 static const char content_length[] = "Content-Length";
@@ -518,13 +520,13 @@ static void get_info_packs(struct strbuf *hdr, char *arg)
 
 	select_getanyfile(hdr);
 	prepare_packed_git();
-	for (p = packed_git; p; p = p->next) {
+	for (p = get_packed_git(the_repository); p; p = p->next) {
 		if (p->pack_local)
 			cnt++;
 	}
 
 	strbuf_grow(&buf, cnt * 53 + 2);
-	for (p = packed_git; p; p = p->next) {
+	for (p = get_packed_git(the_repository); p; p = p->next) {
 		if (p->pack_local)
 			strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
 	}
diff --git a/http-push.c b/http-push.c
index ff82b63133..c0998fd763 100644
--- a/http-push.c
+++ b/http-push.c
@@ -12,6 +12,7 @@
 #include "sigchain.h"
 #include "argv-array.h"
 #include "packfile.h"
+#include "object-store.h"
 
 #ifdef EXPAT_NEEDS_XMLPARSE_H
 #include <xmlparse.h>
diff --git a/http-walker.c b/http-walker.c
index f506f394ac..7cdfb2f24c 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -1,10 +1,12 @@
 #include "cache.h"
+#include "repository.h"
 #include "commit.h"
 #include "walker.h"
 #include "http.h"
 #include "list.h"
 #include "transport.h"
 #include "packfile.h"
+#include "object-store.h"
 
 struct alt_base {
 	char *base;
@@ -545,7 +547,7 @@ static int fetch_object(struct walker *walker, unsigned char *sha1)
 		ret = error("File %s has bad hash", hex);
 	} else if (req->rename < 0) {
 		struct strbuf buf = STRBUF_INIT;
-		sha1_file_name(&buf, req->sha1);
+		sha1_file_name(the_repository, &buf, req->sha1);
 		ret = error("unable to write sha1 filename %s", buf.buf);
 		strbuf_release(&buf);
 	}
diff --git a/http.c b/http.c
index a5bd5d62c2..9304045b6c 100644
--- a/http.c
+++ b/http.c
@@ -14,6 +14,7 @@
 #include "packfile.h"
 #include "protocol.h"
 #include "string-list.h"
+#include "object-store.h"
 
 static struct trace_key trace_curl = TRACE_KEY_INIT(CURL);
 static int trace_curl_data = 1;
@@ -2248,7 +2249,7 @@ struct http_object_request *new_http_object_request(const char *base_url,
 	hashcpy(freq->sha1, sha1);
 	freq->localfile = -1;
 
-	sha1_file_name(&filename, sha1);
+	sha1_file_name(the_repository, &filename, sha1);
 	snprintf(freq->tmpfile, sizeof(freq->tmpfile),
 		 "%s.temp", filename.buf);
 
@@ -2397,8 +2398,7 @@ int finish_http_object_request(struct http_object_request *freq)
 		unlink_or_warn(freq->tmpfile);
 		return -1;
 	}
-
-	sha1_file_name(&filename, freq->sha1);
+	sha1_file_name(the_repository, &filename, freq->sha1);
 	freq->rename = finalize_object_file(freq->tmpfile, filename.buf);
 	strbuf_release(&filename);
 
diff --git a/object-store.h b/object-store.h
new file mode 100644
index 0000000000..fef33f345f
--- /dev/null
+++ b/object-store.h
@@ -0,0 +1,132 @@
+#ifndef OBJECT_STORE_H
+#define OBJECT_STORE_H
+
+struct alternate_object_database {
+	struct alternate_object_database *next;
+
+	/* see alt_scratch_buf() */
+	struct strbuf scratch;
+	size_t base_len;
+
+	/*
+	 * Used to store the results of readdir(3) calls when searching
+	 * for unique abbreviated hashes.  This cache is never
+	 * invalidated, thus it's racy and not necessarily accurate.
+	 * That's fine for its purpose; don't use it for tasks requiring
+	 * greater accuracy!
+	 */
+	char loose_objects_subdir_seen[256];
+	struct oid_array loose_objects_cache;
+
+	/*
+	 * Path to the alternative object store. If this is a relative path,
+	 * it is relative to the current working directory.
+	 */
+	char path[FLEX_ARRAY];
+};
+void prepare_alt_odb(struct repository *r);
+char *compute_alternate_path(const char *path, struct strbuf *err);
+typedef int alt_odb_fn(struct alternate_object_database *, void *);
+int foreach_alt_odb(alt_odb_fn, void*);
+
+/*
+ * Allocate a "struct alternate_object_database" but do _not_ actually
+ * add it to the list of alternates.
+ */
+struct alternate_object_database *alloc_alt_odb(const char *dir);
+
+/*
+ * Add the directory to the on-disk alternates file; the new entry will also
+ * take effect in the current process.
+ */
+void add_to_alternates_file(const char *dir);
+
+/*
+ * Add the directory to the in-memory list of alternates (along with any
+ * recursive alternates it points to), but do not modify the on-disk alternates
+ * file.
+ */
+void add_to_alternates_memory(const char *dir);
+
+/*
+ * Returns a scratch strbuf pre-filled with the alternate object directory,
+ * including a trailing slash, which can be used to access paths in the
+ * alternate. Always use this over direct access to alt->scratch, as it
+ * cleans up any previous use of the scratch buffer.
+ */
+struct strbuf *alt_scratch_buf(struct alternate_object_database *alt);
+
+struct packed_git {
+	struct packed_git *next;
+	struct list_head mru;
+	struct pack_window *windows;
+	off_t pack_size;
+	const void *index_data;
+	size_t index_size;
+	uint32_t num_objects;
+	uint32_t num_bad_objects;
+	unsigned char *bad_object_sha1;
+	int index_version;
+	time_t mtime;
+	int pack_fd;
+	unsigned pack_local:1,
+		 pack_keep:1,
+		 freshened:1,
+		 do_not_close:1,
+		 pack_promisor:1;
+	unsigned char sha1[20];
+	struct revindex_entry *revindex;
+	/* something like ".git/objects/pack/xxxxx.pack" */
+	char pack_name[FLEX_ARRAY]; /* more */
+};
+
+struct raw_object_store {
+	/*
+	 * Path to the repository's object store.
+	 * Cannot be NULL after initialization.
+	 */
+	char *objectdir;
+
+	/* Path to extra alternate object database if not NULL */
+	char *alternate_db;