fetch: align per-ref summary report in UTF-8 locales

fetch does printf("%-*s", width, "foo") where "foo" can be a utf-8
string, but width is in bytes, not columns. For ASCII it's fine as one
byte takes one column. For utf-8, this may result in misaligned ref
summary table.

Introduce gettext_width() function that returns the string length in
columns (currently only supports utf-8 locales). Make the code use
TRANSPORT_SUMMARY(x) where the length is compensated properly in
non-English locales.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fetch.c

@@ -255,9 +255,8 @@ static int update_local_ref(struct ref *ref,
 	if (!hashcmp(ref->old_sha1, ref->new_sha1)) {
 		if (verbosity > 0)
 			strbuf_addf(display, "= %-*s %-*s -> %s",
-				    TRANSPORT_SUMMARY_WIDTH,
-				    _("[up to date]"), REFCOL_WIDTH,
-				    remote, pretty_ref);
+				    TRANSPORT_SUMMARY(_("[up to date]")),
+				    REFCOL_WIDTH, remote, pretty_ref);
 		return 0;
 	}
 
@@ -271,7 +270,7 @@ static int update_local_ref(struct ref *ref,
 		 */
 		strbuf_addf(display,
 			    _("! %-*s %-*s -> %s  (can't fetch in current branch)"),
-			    TRANSPORT_SUMMARY_WIDTH, _("[rejected]"),
+			    TRANSPORT_SUMMARY(_("[rejected]")),
 			    REFCOL_WIDTH, remote, pretty_ref);
 		return 1;
 	}
@@ -282,7 +281,7 @@ static int update_local_ref(struct ref *ref,
 		r = s_update_ref("updating tag", ref, 0);
 		strbuf_addf(display, "%c %-*s %-*s -> %s%s",
 			    r ? '!' : '-',
-			    TRANSPORT_SUMMARY_WIDTH, _("[tag update]"),
+			    TRANSPORT_SUMMARY(_("[tag update]")),
 			    REFCOL_WIDTH, remote, pretty_ref,
 			    r ? _("  (unable to update local ref)") : "");
 		return r;
@@ -317,7 +316,7 @@ static int update_local_ref(struct ref *ref,
 		r = s_update_ref(msg, ref, 0);
 		strbuf_addf(display, "%c %-*s %-*s -> %s%s",
 			    r ? '!' : '*',
-			    TRANSPORT_SUMMARY_WIDTH, what,
+			    TRANSPORT_SUMMARY(what),
 			    REFCOL_WIDTH, remote, pretty_ref,
 			    r ? _("  (unable to update local ref)") : "");
 		return r;
@@ -357,7 +356,7 @@ static int update_local_ref(struct ref *ref,
 		return r;
 	} else {
 		strbuf_addf(display, "! %-*s %-*s -> %s  %s",
-			    TRANSPORT_SUMMARY_WIDTH, _("[rejected]"),
+			    TRANSPORT_SUMMARY(_("[rejected]")),
 			    REFCOL_WIDTH, remote, pretty_ref,
 			    _("(non-fast-forward)"));
 		return 1;
@@ -554,7 +553,7 @@ static int prune_refs(struct refspec *refs, int ref_count, struct ref *ref_map)
 			result |= delete_ref(ref->name, NULL, 0);
 		if (verbosity >= 0) {
 			fprintf(stderr, " x %-*s %-*s -> %s\n",
-				TRANSPORT_SUMMARY_WIDTH, _("[deleted]"),
+				TRANSPORT_SUMMARY(_("[deleted]")),
 				REFCOL_WIDTH, _("(none)"), prettify_refname(ref->name));
 			warn_dangling_symref(stderr, dangling_msg, ref->name);
 		}

gettext.c

@@ -4,6 +4,8 @@
 
 #include "git-compat-util.h"
 #include "gettext.h"
+#include "strbuf.h"
+#include "utf8.h"
 
 #ifndef NO_GETTEXT
 #	include <locale.h>
@@ -27,10 +29,9 @@ int use_gettext_poison(void)
 #endif
 
 #ifndef NO_GETTEXT
+static const char *charset;
 static void init_gettext_charset(const char *domain)
 {
-	const char *charset;
-
 	/*
 	   This trick arranges for messages to be emitted in the user's
 	   requested encoding, but avoids setting LC_CTYPE from the
@@ -128,4 +129,14 @@ void git_setup_gettext(void)
 	init_gettext_charset("git");
 	textdomain("git");
 }
+
+/* return the number of columns of string 's' in current locale */
+int gettext_width(const char *s)
+{
+	static int is_utf8 = -1;
+	if (is_utf8 == -1)
+		is_utf8 = !strcmp(charset, "UTF-8");
+
+	return is_utf8 ? utf8_strwidth(s) : strlen(s);
+}
 #endif

gettext.h

@@ -30,10 +30,15 @@
 
 #ifndef NO_GETTEXT
 extern void git_setup_gettext(void);
+extern int gettext_width(const char *s);
 #else
 static inline void git_setup_gettext(void)
 {
 }
+static inline int gettext_width(const char *s)
+{
+	return strlen(s);
+}
 #endif
 
 #ifdef GETTEXT_POISON

transport.h

@@ -106,6 +106,7 @@ struct transport {
 #define TRANSPORT_RECURSE_SUBMODULES_ON_DEMAND 256
 
 #define TRANSPORT_SUMMARY_WIDTH (2 * DEFAULT_ABBREV + 3)
+#define TRANSPORT_SUMMARY(x) (int)(TRANSPORT_SUMMARY_WIDTH + strlen(x) - gettext_width(x)), (x)
 
 /* Returns a transport suitable for the url */
 struct transport *transport_get(struct remote *, const char *);