ref-filter: introduce remote_ref_atom_parser()

Introduce remote_ref_atom_parser() which will parse the '%(upstream)'
and '%(push)' atoms and store information into the 'used_atom'
structure based on the modifiers used along with the corresponding
atom.

Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Karthik Nayak <Karthik.188@gmail.com>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

ref-filter.c

@@ -37,6 +37,8 @@ static struct used_atom {
 	union {
 		char color[COLOR_MAXLEN];
 		struct align align;
+		enum { RR_NORMAL, RR_SHORTEN, RR_TRACK, RR_TRACKSHORT }
+			remote_ref;
 	} u;
 } *used_atom;
 static int used_atom_cnt, need_tagged, need_symref;
@@ -50,6 +52,20 @@ static void color_atom_parser(struct used_atom *atom, const char *color_value)
 		die(_("unrecognized color: %%(color:%s)"), color_value);
 }
 
+static void remote_ref_atom_parser(struct used_atom *atom, const char *arg)
+{
+	if (!arg)
+		atom->u.remote_ref = RR_NORMAL;
+	else if (!strcmp(arg, "short"))
+		atom->u.remote_ref = RR_SHORTEN;
+	else if (!strcmp(arg, "track"))
+		atom->u.remote_ref = RR_TRACK;
+	else if (!strcmp(arg, "trackshort"))
+		atom->u.remote_ref = RR_TRACKSHORT;
+	else
+		die(_("unrecognized format: %%(%s)"), atom->name);
+}
+
 static align_type parse_align_position(const char *s)
 {
 	if (!strcmp(s, "right"))
@@ -132,8 +148,8 @@ static struct {
 	{ "subject" },
 	{ "body" },
 	{ "contents" },
-	{ "upstream" },
-	{ "push" },
+	{ "upstream", FIELD_STR, remote_ref_atom_parser },
+	{ "push", FIELD_STR, remote_ref_atom_parser },
 	{ "symref" },
 	{ "flag" },
 	{ "HEAD" },
@@ -840,6 +856,43 @@ static const char *strip_ref_components(const char *refname, const char *nr_arg)
 	return start;
 }
 
+static void fill_remote_ref_details(struct used_atom *atom, const char *refname,
+				    struct branch *branch, const char **s)
+{
+	int num_ours, num_theirs;
+	if (atom->u.remote_ref == RR_SHORTEN)
+		*s = shorten_unambiguous_ref(refname, warn_ambiguous_refs);
+	else if (atom->u.remote_ref == RR_TRACK) {
+		if (stat_tracking_info(branch, &num_ours,
+				       &num_theirs, NULL))
+			return;
+
+		if (!num_ours && !num_theirs)
+			*s = "";
+		else if (!num_ours)
+			*s = xstrfmt("[behind %d]", num_theirs);
+		else if (!num_theirs)
+			*s = xstrfmt("[ahead %d]", num_ours);
+		else
+			*s = xstrfmt("[ahead %d, behind %d]",
+				     num_ours, num_theirs);
+	} else if (atom->u.remote_ref == RR_TRACKSHORT) {
+		if (stat_tracking_info(branch, &num_ours,
+				       &num_theirs, NULL))
+			return;
+
+		if (!num_ours && !num_theirs)
+			*s = "=";
+		else if (!num_ours)
+			*s = "<";
+		else if (!num_theirs)
+			*s = ">";
+		else
+			*s = "<>";
+	} else /* RR_NORMAL */
+		*s = refname;
+}
+
 /*
  * Parse the object referred by ref, and grab needed value.
  */
@@ -891,8 +944,9 @@ static void populate_value(struct ref_array_item *ref)
 			branch = branch_get(branch_name);
 
 			refname = branch_get_upstream(branch, NULL);
-			if (!refname)
-				continue;
+			if (refname)
+				fill_remote_ref_details(atom, refname, branch, &v->s);
+			continue;
 		} else if (starts_with(name, "push")) {
 			const char *branch_name;
 			if (!skip_prefix(ref->refname, "refs/heads/",
@@ -903,6 +957,8 @@ static void populate_value(struct ref_array_item *ref)
 			refname = branch_get_push(branch, NULL);
 			if (!refname)
 				continue;
+			fill_remote_ref_details(atom, refname, branch, &v->s);
+			continue;
 		} else if (starts_with(name, "color:")) {
 			v->s = atom->u.color;
 			continue;
@@ -944,7 +1000,6 @@ static void populate_value(struct ref_array_item *ref)
 
 		formatp = strchr(name, ':');
 		if (formatp) {
-			int num_ours, num_theirs;
 			const char *arg;
 
 			formatp++;
@@ -953,43 +1008,7 @@ static void populate_value(struct ref_array_item *ref)
 						      warn_ambiguous_refs);
 			else if (skip_prefix(formatp, "strip=", &arg))
 				refname = strip_ref_components(refname, arg);
-			else if (!strcmp(formatp, "track") &&
-				 (starts_with(name, "upstream") ||
-				  starts_with(name, "push"))) {
-
-				if (stat_tracking_info(branch, &num_ours,
-						       &num_theirs, NULL))
-					continue;
-
-				if (!num_ours && !num_theirs)
-					v->s = "";
-				else if (!num_ours)
-					v->s = xstrfmt("[behind %d]", num_theirs);
-				else if (!num_theirs)
-					v->s = xstrfmt("[ahead %d]", num_ours);
-				else
-					v->s = xstrfmt("[ahead %d, behind %d]",
-						       num_ours, num_theirs);
-				continue;
-			} else if (!strcmp(formatp, "trackshort") &&
-				   (starts_with(name, "upstream") ||
-				    starts_with(name, "push"))) {
-				assert(branch);
-
-				if (stat_tracking_info(branch, &num_ours,
-							&num_theirs, NULL))
-					continue;
-
-				if (!num_ours && !num_theirs)
-					v->s = "=";
-				else if (!num_ours)
-					v->s = "<";
-				else if (!num_theirs)
-					v->s = ">";
-				else
-					v->s = "<>";
-				continue;
-			} else
+			else
 				die("unknown %.*s format %s",
 				    (int)(formatp - name), name, formatp);
 		}