clone: clone from a repository with relative alternates

diff --git a/builtin/clone.c b/builtin/clone.c
index ee5d6518c8f8ad7e713ab05fea52f6b79fa493fa..16b4fba71f8fed16ac67ee09b186e0295fc6b6da 100644 (file)
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -209,34 +209,34 @@ static void strip_trailing_slashes(char *dir)
 
 static int add_one_reference(struct string_list_item *item, void *cb_data)
 {
-       const char *ref_git;
-       char *ref_git_copy;
-
+       char *ref_git;
+       struct strbuf alternate = STRBUF_INIT;
        struct remote *remote;
        struct transport *transport;
        const struct ref *extra;
 
-       ref_git = real_path(item->string);
-
-       if (is_directory(mkpath("%s/.git/objects", ref_git)))
-               ref_git = mkpath("%s/.git", ref_git);
-       else if (!is_directory(mkpath("%s/objects", ref_git)))
+       /* Beware: real_path() and mkpath() return static buffer */
+       ref_git = xstrdup(real_path(item->string));
+       if (is_directory(mkpath("%s/.git/objects", ref_git))) {
+               char *ref_git_git = xstrdup(mkpath("%s/.git", ref_git));
+               free(ref_git);
+               ref_git = ref_git_git;
+       } else if (!is_directory(mkpath("%s/objects", ref_git)))
                die(_("reference repository '%s' is not a local directory."),
                    item->string);
 
-       ref_git_copy = xstrdup(ref_git);
-
-       add_to_alternates_file(ref_git_copy);
+       strbuf_addf(&alternate, "%s/objects", ref_git);
+       add_to_alternates_file(alternate.buf);
+       strbuf_release(&alternate);
 
-       remote = remote_get(ref_git_copy);
-       transport = transport_get(remote, ref_git_copy);
+       remote = remote_get(ref_git);
+       transport = transport_get(remote, ref_git);
        for (extra = transport_get_remote_refs(transport); extra;
             extra = extra->next)
                add_extra_ref(extra->name, extra->old_sha1, 0);
 
        transport_disconnect(transport);
-
-       free(ref_git_copy);
+       free(ref_git);
        return 0;
 }
 
@@ -245,7 +245,42 @@ static void setup_reference(void)
        for_each_string_list(&option_reference, add_one_reference, NULL);
 }
 
-static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest)
+static void copy_alternates(struct strbuf *src, struct strbuf *dst,
+                           const char *src_repo)
+{
+       /*
+        * Read from the source objects/info/alternates file
+        * and copy the entries to corresponding file in the
+        * destination repository with add_to_alternates_file().
+        * Both src and dst have "$path/objects/info/alternates".
+        *
+        * Instead of copying bit-for-bit from the original,
+        * we need to append to existing one so that the already
+        * created entry via "clone -s" is not lost, and also
+        * to turn entries with paths relative to the original
+        * absolute, so that they can be used in the new repository.
+        */
+       FILE *in = fopen(src->buf, "r");
+       struct strbuf line = STRBUF_INIT;
+
+       while (strbuf_getline(&line, in, '\n') != EOF) {
+               char *abs_path, abs_buf[PATH_MAX];
+               if (!line.len || line.buf[0] == '#')
+                       continue;
+               if (is_absolute_path(line.buf)) {
+                       add_to_alternates_file(line.buf);
+                       continue;
+               }
+               abs_path = mkpath("%s/objects/%s", src_repo, line.buf);
+               normalize_path_copy(abs_buf, abs_path);
+               add_to_alternates_file(abs_buf);
+       }
+       strbuf_release(&line);
+       fclose(in);
+}
+
+static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
+                                  const char *src_repo, int src_baselen)
 {
        struct dirent *de;
        struct stat buf;
@@ -281,7 +316,14 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest)
                }
                if (S_ISDIR(buf.st_mode)) {
                        if (de->d_name[0] != '.')
-                               copy_or_link_directory(src, dest);
+                               copy_or_link_directory(src, dest,
+                                                      src_repo, src_baselen);
+                       continue;
+               }
+
+               /* Files that cannot be copied bit-for-bit... */
+               if (!strcmp(src->buf + src_baselen, "/info/alternates")) {
+                       copy_alternates(src, dest, src_repo);
                        continue;
                }
 
@@ -304,17 +346,20 @@ static const struct ref *clone_local(const char *src_repo,
                                     const char *dest_repo)
 {
        const struct ref *ret;
-       struct strbuf src = STRBUF_INIT;
-       struct strbuf dest = STRBUF_INIT;
        struct remote *remote;
        struct transport *transport;
 
-       if (option_shared)
-               add_to_alternates_file(src_repo);
-       else {
+       if (option_shared) {
+               struct strbuf alt = STRBUF_INIT;
+               strbuf_addf(&alt, "%s/objects", src_repo);
+               add_to_alternates_file(alt.buf);
+               strbuf_release(&alt);
+       } else {
+               struct strbuf src = STRBUF_INIT;
+               struct strbuf dest = STRBUF_INIT;
                strbuf_addf(&src, "%s/objects", src_repo);
                strbuf_addf(&dest, "%s/objects", dest_repo);
-               copy_or_link_directory(&src, &dest);
+               copy_or_link_directory(&src, &dest, src_repo, src.len);
                strbuf_release(&src);
                strbuf_release(&dest);
        }