[PATCH v5 4/5] fetch: align all "remote -> local" output

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

We do align "remote -> local" output by allocating 10 columns to
"remote". That produces aligned output only for short refs. An extra
pass is performed to find the longest remote ref name (that does not
produce a line longer than terminal width) to produce better aligned
output.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 builtin/fetch.c  | 47 +++++++++++++++++++++++++++++++++++++++++++++--
 t/t5510-fetch.sh | 15 +++++++++++++++
 2 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 8177f90..2bc609b 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -15,6 +15,7 @@
 #include "submodule.h"
 #include "connected.h"
 #include "argv-array.h"
+#include "utf8.h"
 
 static const char * const builtin_fetch_usage[] = {
 	N_("git fetch [<options>] [<repository> [<refspec>...]]"),
@@ -449,14 +450,54 @@ fail:
 			   : STORE_REF_ERROR_OTHER;
 }
 
-#define REFCOL_WIDTH  10
+static int refcol_width = 10;
+
+static void adjust_refcol_width(const struct ref *ref)
+{
+	int max, rlen, llen, len;
+
+	/* uptodate lines are only shown on high verbosity level */
+	if (!verbosity && !oidcmp(&ref->peer_ref->old_oid, &ref->old_oid))
+		return;
+
+	max    = term_columns();
+	rlen   = utf8_strwidth(prettify_refname(ref->name));
+	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)
+		return;
+
+	if (refcol_width < rlen)
+		refcol_width = rlen;
+}
+
+static void prepare_format_display(struct ref *ref_map)
+{
+	struct ref *rm;
+
+	for (rm = ref_map; rm; rm = rm->next) {
+		if (rm->status == REF_STATUS_REJECT_SHALLOW ||
+		    !rm->peer_ref ||
+		    !strcmp(rm->name, "HEAD"))
+			continue;
+
+		adjust_refcol_width(rm);
+	}
+}
 
 static void format_display(struct strbuf *display, char code,
 			   const char *summary, const char *error,
 			   const char *remote, const char *local)
 {
 	strbuf_addf(display, "%c %-*s ", code, TRANSPORT_SUMMARY(summary));
-	strbuf_addf(display, "%-*s -> %s", REFCOL_WIDTH, remote, local);
+	strbuf_addf(display, "%-*s -> %s", refcol_width, remote, local);
 	if (error)
 		strbuf_addf(display, "  (%s)", error);
 }
@@ -618,6 +659,8 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 		goto abort;
 	}
 
+	prepare_format_display(ref_map);
+
 	/*
 	 * We do a pass for each fetch_head_status type in their enum order, so
 	 * merged entries are written before not-for-merge. That lets readers
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 454d896..f50497e 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -688,4 +688,19 @@ test_expect_success 'fetching with auto-gc does not lock up' '
 	)
 '
 
+test_expect_success 'fetch aligned output' '
+	git clone . full-output &&
+	test_commit looooooooooooong-tag &&
+	(
+		cd full-output &&
+		git fetch origin 2>&1 | \
+			grep -e "->" | cut -c 22- >../actual
+	) &&
+	cat >expect <<-\EOF &&
+	master               -> origin/master
+	looooooooooooong-tag -> looooooooooooong-tag
+	EOF
+	test_cmp expect actual
+'
+
 test_done
-- 
2.8.2.531.gd073806