Add a library function to add an alternate to the alternates file

diff --git a/sha1_file.c b/sha1_file.c
index 3516777bc7614c23da02dd7a9aa28a48294d56cb..d21e23b4647225af0c38bb70f8b3140972367f3e 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -380,6 +380,18 @@ static void read_info_alternates(const char * relative_base, int depth)
        munmap(map, mapsz);
 }
 
+void add_to_alternates_file(const char *reference)
+{
+       struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+       int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), 1);
+       char *alt = mkpath("%s/objects\n", reference);
+       write_or_die(fd, alt, strlen(alt));
+       if (commit_lock_file(lock))
+               die("could not close alternates file");
+       if (alt_odb_tail)
+               link_alt_odb_entries(alt, alt + strlen(alt), '\n', NULL, 0);
+}
+
 void prepare_alt_odb(void)
 {
        const char *alt;