fetch: refactor calculation of the display table width

When displaying reference updates, we try to print the references in a
neat table. As the table's width is determined its contents we thus need
to precalculate the overall width before we can start printing updated
references.

The calculation is driven by `display_state_init()`, which invokes
`refcol_width()` for every reference that is to be printed. This split
is somewhat confusing. For one, we filter references that shall be
attributed to the overall width in both places. And second, we
needlessly recalculate the maximum line length based on the terminal
columns and display format for every reference.

Refactor the code so that the complete width calculations are neatly
contained in `refcol_width()`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fetch.c

@@ -753,40 +753,51 @@ static int s_update_ref(const char *action,
 	return ret;
 }
 
-static int refcol_width(const struct ref *ref, int compact_format)
+static int refcol_width(const struct ref *ref_map, int compact_format)
 {
-	int max, rlen, llen, len;
+	const struct ref *ref;
+	int max, width = 10;
 
-	/* uptodate lines are only shown on high verbosity level */
-	if (verbosity <= 0 && oideq(&ref->peer_ref->old_oid, &ref->old_oid))
-		return 0;
+	max = term_columns();
+	if (compact_format)
+		max = max * 2 / 3;
 
-	max    = term_columns();
-	rlen   = utf8_strwidth(prettify_refname(ref->name));
+	for (ref = ref_map; ref; ref = ref->next) {
+		int rlen, llen = 0, len;
 
-	llen   = utf8_strwidth(prettify_refname(ref->peer_ref->name));
+		if (ref->status == REF_STATUS_REJECT_SHALLOW ||
+		    !ref->peer_ref ||
+		    !strcmp(ref->name, "HEAD"))
+			continue;
 
-	/*
-	 * rough estimation to see if the output line is too long and
-	 * should not be counted (we can't do precise calculation
-	 * anyway because we don't know if the error explanation part
-	 * will be printed in update_local_ref)
-	 */
-	if (compact_format) {
-		llen = 0;
-		max = max * 2 / 3;
+		/* uptodate lines are only shown on high verbosity level */
+		if (verbosity <= 0 && oideq(&ref->peer_ref->old_oid, &ref->old_oid))
+			continue;
+
+		rlen = utf8_strwidth(prettify_refname(ref->name));
+		if (!compact_format)
+			llen = utf8_strwidth(prettify_refname(ref->peer_ref->name));
+
+		/*
+		 * rough estimation to see if the output line is too long and
+		 * should not be counted (we can't do precise calculation
+		 * anyway because we don't know if the error explanation part
+		 * will be printed in update_local_ref)
+		 */
+		len = 21 /* flag and summary */ + rlen + 4 /* -> */ + llen;
+		if (len >= max)
+			continue;
+
+		if (width < rlen)
+			width = rlen;
 	}
-	len = 21 /* flag and summary */ + rlen + 4 /* -> */ + llen;
-	if (len >= max)
-		return 0;
 
-	return rlen;
+	return width;
 }
 
 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;
 
@@ -818,25 +829,7 @@ static void display_state_init(struct display_state *display_state, struct ref *
 		die(_("invalid value for '%s': '%s'"),
 		    "fetch.output", format);
 
-	display_state->refcol_width = 10;
-	for (rm = ref_map; rm; rm = rm->next) {
-		int width;
-
-		if (rm->status == REF_STATUS_REJECT_SHALLOW ||
-		    !rm->peer_ref ||
-		    !strcmp(rm->name, "HEAD"))
-			continue;
-
-		width = refcol_width(rm, display_state->compact_format);
-
-		/*
-		 * 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;
-	}
+	display_state->refcol_width = refcol_width(ref_map, display_state->compact_format);
 }
 
 static void display_state_release(struct display_state *display_state)