interpret_branch_name: factor out upstream handling

This function checks a few different @{}-constructs. The
early part checks for and dispatches us to helpers for each
construct, but the code for handling @{upstream} is inline.

Let's factor this out into its own function. This makes
interpret_branch_name more readable, and will make it much
simpler to further refactor the function in future patches.

While we're at it, let's also break apart the refactored
code into a few helper functions. These will be useful if we
eventually implement similar @{upstream}-like constructs.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/sha1_name.c b/sha1_name.c
index e9c299943b817b5b3b5b700ac3979211d5688e2e..03c574e29599cfea0fac944038f4545e29517ce4 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1048,6 +1048,54 @@ static int reinterpret(const char *name, int namelen, int len, struct strbuf *bu
        return ret - used + len;
 }
 
+static void set_shortened_ref(struct strbuf *buf, const char *ref)
+{
+       char *s = shorten_unambiguous_ref(ref, 0);
+       strbuf_reset(buf);
+       strbuf_addstr(buf, s);
+       free(s);
+}
+
+static const char *get_upstream_branch(const char *branch_buf, int len)
+{
+       char *branch = xstrndup(branch_buf, len);
+       struct branch *upstream = branch_get(*branch ? branch : NULL);
+
+       /*
+        * Upstream can be NULL only if branch refers to HEAD and HEAD
+        * points to something different than a branch.
+        */
+       if (!upstream)
+               die(_("HEAD does not point to a branch"));
+       if (!upstream->merge || !upstream->merge[0]->dst) {
+               if (!ref_exists(upstream->refname))
+                       die(_("No such branch: '%s'"), branch);
+               if (!upstream->merge) {
+                       die(_("No upstream configured for branch '%s'"),
+                               upstream->name);
+               }
+               die(
+                       _("Upstream branch '%s' not stored as a remote-tracking branch"),
+                       upstream->merge[0]->src);
+       }
+       free(branch);
+
+       return upstream->merge[0]->dst;
+}
+
+static int interpret_upstream_mark(const char *name, int namelen,
+                                  int at, struct strbuf *buf)
+{
+       int len;
+
+       len = upstream_mark(name + at, namelen - at);
+       if (!len)
+               return -1;
+
+       set_shortened_ref(buf, get_upstream_branch(name, at));
+       return len + at;
+}
+
 /*
  * This reads short-hand syntax that not only evaluates to a commit
  * object name, but also can act as if the end user spelled the name
@@ -1072,9 +1120,7 @@ static int reinterpret(const char *name, int namelen, int len, struct strbuf *bu
 int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
 {
        char *cp;
-       struct branch *upstream;
        int len = interpret_nth_prior_checkout(name, buf);
-       int tmp_len;
 
        if (!namelen)
                namelen = strlen(name);
@@ -1096,36 +1142,11 @@ int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
        if (len > 0)
                return reinterpret(name, namelen, len, buf);
 
-       tmp_len = upstream_mark(cp, namelen - (cp - name));
-       if (!tmp_len)
-               return -1;
+       len = interpret_upstream_mark(name, namelen, cp - name, buf);
+       if (len > 0)
+               return len;
 
-       len = cp + tmp_len - name;
-       cp = xstrndup(name, cp - name);
-       upstream = branch_get(*cp ? cp : NULL);
-       /*
-        * Upstream can be NULL only if cp refers to HEAD and HEAD
-        * points to something different than a branch.
-        */
-       if (!upstream)
-               die(_("HEAD does not point to a branch"));
-       if (!upstream->merge || !upstream->merge[0]->dst) {
-               if (!ref_exists(upstream->refname))
-                       die(_("No such branch: '%s'"), cp);
-               if (!upstream->merge) {
-                       die(_("No upstream configured for branch '%s'"),
-                               upstream->name);
-               }
-               die(
-                       _("Upstream branch '%s' not stored as a remote-tracking branch"),
-                       upstream->merge[0]->src);
-       }
-       free(cp);
-       cp = shorten_unambiguous_ref(upstream->merge[0]->dst, 0);
-       strbuf_reset(buf);
-       strbuf_addstr(buf, cp);
-       free(cp);
-       return len;
+       return -1;
 }
 
 int strbuf_branchname(struct strbuf *sb, const char *name)