extern void prepare_alt_odb(void);
extern void read_info_alternates(const char * relative_base, int depth);
extern char *compute_alternate_path(const char *path, struct strbuf *err);
-extern void add_to_alternates_file(const char *reference);
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);
+
struct pack_window {
struct pack_window *next;
unsigned char *base;