We currently have two different display formats in git-fetch(1) with the
"full" and "compact" formats. This is tracked with a boolean value that
simply denotes whether the display format is supposed to be compacted
or not. This works reasonably well while there are only two formats, but
we're about to introduce another format that will make this a bit more
awkward to use.

Introduce a `enum display_format` that is more readily extensible.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 builtin/fetch.c | 101 ++++++++++++++++++++++++++++++------------------
 1 file changed, 64 insertions(+), 37 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 7c64f0c562..e03fcd1b2f 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -48,11 +48,17 @@ enum {
 	TAGS_SET = 2
 };
 
+enum display_format {
+	DISPLAY_FORMAT_UNKNOWN = 0,
+	DISPLAY_FORMAT_FULL,
+	DISPLAY_FORMAT_COMPACT,
+};
+
 struct display_state {
 	struct strbuf buf;
 
 	int refcol_width;
-	int compact_format;
+	enum display_format format;
 
 	char *url;
 	int url_len, shown_url;
@@ -784,7 +790,6 @@ static int refcol_width(const struct ref *ref, int compact_format)
 static void display_state_init(struct display_state *display_state, struct ref *ref_map,
 			       const char *raw_url)
 {
-	struct ref *rm;
 	const char *format = "full";
 	int i;
 
@@ -809,31 +814,42 @@ static void display_state_init(struct display_state *display_state, struct ref *
 
 	git_config_get_string_tmp("fetch.output", &format);
 	if (!strcasecmp(format, "full"))
-		display_state->compact_format = 0;
+		display_state->format = DISPLAY_FORMAT_FULL;
 	else if (!strcasecmp(format, "compact"))
-		display_state->compact_format = 1;
+		display_state->format = DISPLAY_FORMAT_COMPACT;
 	else
 		die(_("invalid value for '%s': '%s'"),
 		    "fetch.output", format);
 
-	display_state->refcol_width = 10;
-	for (rm = ref_map; rm; rm = rm->next) {
-		int width;
+	switch (display_state->format) {
+	case DISPLAY_FORMAT_FULL:
+	case DISPLAY_FORMAT_COMPACT: {
+		struct ref *rm;
 
-		if (rm->status == REF_STATUS_REJECT_SHALLOW ||
-		    !rm->peer_ref ||
-		    !strcmp(rm->name, "HEAD"))
-			continue;
+		display_state->refcol_width = 10;
+		for (rm = ref_map; rm; rm = rm->next) {
+			int width;
 
-		width = refcol_width(rm, display_state->compact_format);
+			if (rm->status == REF_STATUS_REJECT_SHALLOW ||
+			    !rm->peer_ref ||
+			    !strcmp(rm->name, "HEAD"))
+				continue;
 
-		/*
-		 * Not precise calculation for compact mode because '*' can
-		 * appear on the left hand side of '->' and shrink the column
-		 * back.
-		 */
-		if (display_state->refcol_width < width)
-			display_state->refcol_width = width;
+			width = refcol_width(rm, display_state->format == DISPLAY_FORMAT_COMPACT);
+
+			/*
+			 * Not precise calculation for compact mode because '*' can
+			 * appear on the left hand side of '->' and shrink the column
+			 * back.
+			 */
+			if (display_state->refcol_width < width)
+				display_state->refcol_width = width;
+		}
+
+		break;
+	}
+	default:
+		BUG("unexpected display foramt %d", display_state->format);
 	}
 }
 
@@ -904,30 +920,41 @@ static void display_ref_update(struct display_state *display_state, char code,
 			       const char *remote, const char *local,
 			       int summary_width)
 {
-	int width;
-
 	if (verbosity < 0)
 		return;
 
 	strbuf_reset(&display_state->buf);
 
-	if (!display_state->shown_url) {
-		strbuf_addf(&display_state->buf, _("From %.*s\n"),
-			    display_state->url_len, display_state->url);
-		display_state->shown_url = 1;
+	switch (display_state->format) {
+	case DISPLAY_FORMAT_FULL:
+	case DISPLAY_FORMAT_COMPACT: {
+		int width;
+
+		if (!display_state->shown_url) {
+			strbuf_addf(&display_state->buf, _("From %.*s\n"),
+				    display_state->url_len, display_state->url);
+			display_state->shown_url = 1;
+		}
+
+		width = (summary_width + strlen(summary) - gettext_width(summary));
+		remote = prettify_refname(remote);
+		local = prettify_refname(local);
+
+		strbuf_addf(&display_state->buf, " %c %-*s ", code, width, summary);
+
+		if (display_state->format != DISPLAY_FORMAT_COMPACT)
+			print_remote_to_local(display_state, remote, local);
+		else
+			print_compact(display_state, remote, local);
+
+		if (error)
+			strbuf_addf(&display_state->buf, "  (%s)", error);
+
+		break;
 	}
-
-	width = (summary_width + strlen(summary) - gettext_width(summary));
-	remote = prettify_refname(remote);
-	local = prettify_refname(local);
-
-	strbuf_addf(&display_state->buf, " %c %-*s ", code, width, summary);
-	if (!display_state->compact_format)
-		print_remote_to_local(display_state, remote, local);
-	else
-		print_compact(display_state, remote, local);
-	if (error)
-		strbuf_addf(&display_state->buf, "  (%s)", error);
+	default:
+		BUG("unexpected display format %d", display_state->format);
+	};
 	strbuf_addch(&display_state->buf, '\n');
 
 	fputs(display_state->buf.buf, stderr);
-- 
2.40.1