[PATCH] Define relative .git/objects/info/alternates semantics.

[git.git] / sha1_file.c

diff --git a/sha1_file.c b/sha1_file.c
index f4c742eed4736e121448eb8d24697aa812a0d158..66382027816e8ec3a97c40f6849c62454f2ad0f2 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -240,10 +240,12 @@ static struct alternate_object_database **alt_odb_tail;
  * SHA1, an extra slash for the first level indirection, and the
  * terminating NUL.
  */
-static void link_alt_odb_entries(const char *alt, const char *ep, int sep)
+static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
+                                const char *relative_base)
 {
        const char *cp, *last;
        struct alternate_object_database *ent;
+       int base_len = -1;
 
        last = alt;
        while (last < ep) {
@@ -261,12 +263,25 @@ static void link_alt_odb_entries(const char *alt, const char *ep, int sep)
                        int pfxlen = cp - last;
                        int entlen = pfxlen + 43;
 
+                       if (*last != '/' && relative_base) {
+                               /* Relative alt-odb */
+                               if (base_len < 0)
+                                       base_len = strlen(relative_base) + 1;
+                               entlen += base_len;
+                               pfxlen += base_len;
+                       }
                        ent = xmalloc(sizeof(*ent) + entlen);
                        *alt_odb_tail = ent;
                        alt_odb_tail = &(ent->next);
                        ent->next = NULL;
-
-                       memcpy(ent->base, last, pfxlen);
+                       if (*last != '/' && relative_base) {
+                               memcpy(ent->base, relative_base, base_len - 1);
+                               ent->base[base_len - 1] = '/';
+                               memcpy(ent->base + base_len,
+                                      last, cp - last);
+                       }
+                       else
+                               memcpy(ent->base, last, pfxlen);
                        ent->name = ent->base + pfxlen + 1;
                        ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
                        ent->base[entlen-1] = 0;
@@ -288,12 +303,12 @@ void prepare_alt_odb(void)
        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
        if (!alt) alt = "";
 
-       sprintf(path, "%s/info/alternates", get_object_directory());
        if (alt_odb_tail)
                return;
        alt_odb_tail = &alt_odb_list;
-       link_alt_odb_entries(alt, alt + strlen(alt), ':');
+       link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
 
+       sprintf(path, "%s/info/alternates", get_object_directory());
        fd = open(path, O_RDONLY);
        if (fd < 0)
                return;
@@ -306,7 +321,8 @@ void prepare_alt_odb(void)
        if (map == MAP_FAILED)
                return;
 
-       link_alt_odb_entries(map, map + st.st_size, '\n');
+       link_alt_odb_entries(map, map + st.st_size, '\n',
+                            get_object_directory());
        munmap(map, st.st_size);
 }