reset.c: extract function for updating {ORIG_,}HEAD

diff --git a/builtin/log.c b/builtin/log.c
index e7b7db1cacf1934a9bb0b96beb98ddda15a66074..3899b1d43acc8c51e7609be94469eac057116440 100644 (file)
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1016,8 +1016,9 @@ static char *find_branch_name(struct rev_info *rev)
 {
        int i, positive = -1;
        unsigned char branch_sha1[20];
-       struct strbuf buf = STRBUF_INIT;
-       const char *branch;
+       const unsigned char *tip_sha1;
+       const char *ref;
+       char *full_ref, *branch = NULL;
 
        for (i = 0; i < rev->cmdline.nr; i++) {
                if (rev->cmdline.rev[i].flags & UNINTERESTING)
@@ -1027,18 +1028,27 @@ static char *find_branch_name(struct rev_info *rev)
                else
                        return NULL;
        }
-       if (positive < 0)
+       if (0 <= positive) {
+               ref = rev->cmdline.rev[positive].name;
+               tip_sha1 = rev->cmdline.rev[positive].item->sha1;
+       } else if (!rev->cmdline.nr && rev->pending.nr == 1 &&
+                  !strcmp(rev->pending.objects[0].name, "HEAD")) {
+               /*
+                * No actual ref from command line, but "HEAD" from
+                * rev->def was added in setup_revisions()
+                * e.g. format-patch --cover-letter -12
+                */
+               ref = "HEAD";
+               tip_sha1 = rev->pending.objects[0].item->sha1;
+       } else {
                return NULL;
-       strbuf_addf(&buf, "refs/heads/%s", rev->cmdline.rev[positive].name);
-       branch = resolve_ref_unsafe(buf.buf, branch_sha1, 1, NULL);
-       if (!branch ||
-           prefixcmp(branch, "refs/heads/") ||
-           hashcmp(rev->cmdline.rev[positive].item->sha1, branch_sha1))
-               branch = NULL;
-       strbuf_release(&buf);
-       if (branch)
-               return xstrdup(rev->cmdline.rev[positive].name);
-       return NULL;
+       }
+       if (dwim_ref(ref, strlen(ref), branch_sha1, &full_ref) &&
+           !prefixcmp(full_ref, "refs/heads/") &&
+           !hashcmp(tip_sha1, branch_sha1))
+               branch = xstrdup(full_ref + strlen("refs/heads/"));
+       free(full_ref);
+       return branch;
 }
 
 int cmd_format_patch(int argc, const char **argv, const char *prefix)