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
  ...

sha1_name.c

@@ -10,6 +10,8 @@
 #include "dir.h"
 #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 *);
 
@@ -104,7 +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;
@@ -178,7 +180,8 @@ static void find_short_packed_object(struct disambiguate_state *ds)
 	struct packed_git *p;
 
 	prepare_packed_git();
-	for (p = packed_git; p && !ds->ambiguous; p = p->next)
+	for (p = get_packed_git(the_repository); p && !ds->ambiguous;
+	     p = p->next)
 		unique_in_pack(p, ds);
 }
 
@@ -334,7 +337,7 @@ static int init_object_disambiguation(const char *name, int len,
 
 	ds->len = len;
 	ds->hex_pfx[len] = '\0';
-	prepare_alt_odb();
+	prepare_alt_odb(the_repository);
 	return 0;
 }
 
@@ -532,7 +535,7 @@ static void find_abbrev_len_packed(struct min_abbrev_data *mad)
 	struct packed_git *p;
 
 	prepare_packed_git();
-	for (p = packed_git; p; p = p->next)
+	for (p = get_packed_git(the_repository); p; p = p->next)
 		find_abbrev_len_for_pack(p, mad);
 }