[PATCH 3/5] progress: assemble percentage and counters in a strbuf before printing

[SZEDER Gábor <szeder.dev@xxxxxxxxx>]

The following patches in this series want to handle the progress bar's
title and changing parts (i.e. the counter and the optional percentage
and throughput combined) differently.

To prepare for those changes assemble the changing parts in a separate
strbuf before printing.

Signed-off-by: SZEDER Gábor <szeder.dev@xxxxxxxxx>
---
 progress.c | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/progress.c b/progress.c
index b57c0dae16..390d2487ca 100644
--- a/progress.c
+++ b/progress.c
@@ -36,6 +36,7 @@ struct progress {
 	unsigned delay;
 	struct throughput *throughput;
 	uint64_t start_ns;
+	struct strbuf counters_sb;
 };
 
 static volatile sig_atomic_t progress_update;
@@ -80,7 +81,9 @@ static int is_foreground_fd(int fd)
 
 static void display(struct progress *progress, uint64_t n, const char *done)
 {
-	const char *eol, *tp;
+	const char *tp;
+	struct strbuf *counters_sb = &progress->counters_sb;
+	int update = 0;
 
 	if (progress->delay && (!progress_update || --progress->delay))
 		return;
@@ -93,25 +96,31 @@ static void display(struct progress *progress, uint64_t n, const char *done)
 	}
 
 	tp = (progress->throughput) ? progress->throughput->display.buf : "";
-	eol = done ? done : "   \r";
 	if (progress->total) {
 		unsigned percent = n * 100 / progress->total;
 		if (percent != progress->last_percent || progress_update) {
 			progress->last_percent = percent;
-			fprintf(stderr, "%s: %3u%% (%"PRIuMAX"/%"PRIuMAX")%s%s",
-				progress->title, percent,
-				(uintmax_t)n, (uintmax_t)progress->total,
-				tp, eol);
-			fflush(stderr);
-			progress_update = 0;
-			return;
+
+			strbuf_reset(counters_sb);
+			strbuf_addf(counters_sb,
+				    "%3u%% (%"PRIuMAX"/%"PRIuMAX")%s", percent,
+				    (uintmax_t)n, (uintmax_t)progress->total,
+				    tp);
+			update = 1;
 		}
 	} else if (progress_update) {
-		fprintf(stderr, "%s: %"PRIuMAX"%s%s",
-			progress->title, (uintmax_t)n, tp, eol);
+		strbuf_reset(counters_sb);
+		strbuf_addf(counters_sb, "%"PRIuMAX"%s", (uintmax_t)n, tp);
+		update = 1;
+	}
+
+	if (update) {
+		const char *eol = done ? done : "   \r";
+
+		fprintf(stderr, "%s: %s%s", progress->title, counters_sb->buf,
+			eol);
 		fflush(stderr);
 		progress_update = 0;
-		return;
 	}
 
 	return;
@@ -213,6 +222,7 @@ static struct progress *start_progress_delay(const char *title, uint64_t total,
 	progress->delay = delay;
 	progress->throughput = NULL;
 	progress->start_ns = getnanotime();
+	strbuf_init(&progress->counters_sb, 0);
 	set_progress_signal();
 	return progress;
 }
@@ -256,6 +266,7 @@ void stop_progress_msg(struct progress **p_progress, const char *msg)
 		free(buf);
 	}
 	clear_progress_signal();
+	strbuf_release(&progress->counters_sb);
 	if (progress->throughput)
 		strbuf_release(&progress->throughput->display);
 	free(progress->throughput);
-- 
2.21.0.539.g07239c3a71.dirty