[PATCH 15/25] progress.c: pass "is done?" (again) to display()

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Go back to passing a "are we done?" state variable to the display()
function, instead of passing a string that happens to end in a newline
for the ", done\n" special-case in stop_progress().

This doesn't matter now, but is needed to display an arbitrary message
earlier in the progress display, not just at the very end.

In a984a06a07c (nicer display of thin pack completion, 2007-11-08)
this code worked like this, but later on in 42e18fbf5f9 (more compact
progress display, 2007-10-16) we ended up with the "const
char *done". Then in d53ba841d4f (progress: assemble percentage and
counters in a strbuf before printing, 2019-04-05) we ended up with the
current code structure around the "counters_sb" strbuf.

The "counters_sb" is needed because when we emit a line like:

    Title (1/10)<CR>

We need to know how many characters the " (1/10)" variable part is, so
that we'll emit the appropriate number of spaces to "clear" the line.

If we want to emit output like:

    Title (1/10), some message<CR>

We'll need to stick the whole " (1/10), some message" part into the
strbuf, so that if we want to clear the message we'll know to emit:

    Title (1/10), some message<CR>
    Title (2/10)              <CR>

This didn't matter for the ", done\n" case because we were ending the
process anyway, but in preparation for the above let's star treating
it like any other line, and pass an "int last_update" to decide
whether the line ends with a "\r" or a "\n".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 progress.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/progress.c b/progress.c
index 39d7f6bd86b..44479f65921 100644
--- a/progress.c
+++ b/progress.c
@@ -25,7 +25,8 @@ static int is_foreground_fd(int fd)
 	return tpgrp < 0 || tpgrp == getpgid(0);
 }
 
-static void display(struct progress *progress, uint64_t n, const char *done)
+static void display(struct progress *progress, uint64_t n,
+		    const char *update_msg, int last_update)
 {
 	const char *tp;
 	struct strbuf *counters_sb = &progress->counters_sb;
@@ -55,10 +56,13 @@ static void display(struct progress *progress, uint64_t n, const char *done)
 		show_update = 1;
 	}
 
+	if (show_update && update_msg)
+		strbuf_addf(counters_sb, ", %s.", update_msg);
+
 	if (show_update) {
 		int stderr_is_foreground_fd = is_foreground_fd(fileno(stderr));
-		if (stderr_is_foreground_fd || done) {
-			const char *eol = done ? done : "\r";
+		if (stderr_is_foreground_fd || update_msg) {
+			const char *eol = last_update ? "\n" : "\r";
 			size_t clear_len = counters_sb->len < last_count_len ?
 					last_count_len - counters_sb->len + 1 :
 					0;
@@ -70,7 +74,7 @@ static void display(struct progress *progress, uint64_t n, const char *done)
 			if (progress->split) {
 				fprintf(stderr, "  %s%*s", counters_sb->buf,
 					(int) clear_len, eol);
-			} else if (!done && cols < progress_line_len) {
+			} else if (!update_msg && cols < progress_line_len) {
 				clear_len = progress->title_len + 1 < cols ?
 					    cols - progress->title_len - 1 : 0;
 				fprintf(stderr, "%s:%*s\n  %s%s",
@@ -163,13 +167,13 @@ void display_throughput(struct progress *progress, uint64_t total)
 
 	throughput_string(&tp->display, total, rate);
 	if (progress->last_value != -1 && progress_update)
-		display(progress, progress->last_value, NULL);
+		display(progress, progress->last_value, NULL, 0);
 }
 
 void display_progress(struct progress *progress, uint64_t n)
 {
 	if (progress)
-		display(progress, n, NULL);
+		display(progress, n, NULL, 0);
 }
 
 static void progress_interval(int signum)
@@ -303,7 +307,6 @@ void stop_progress_msg(struct progress **p_progress, const char *msg)
 	*p_progress = NULL;
 	if (progress->last_value != -1) {
 		/* Force the last update */
-		char *buf;
 		struct throughput *tp = progress->throughput;
 
 		if (tp) {
@@ -314,9 +317,7 @@ void stop_progress_msg(struct progress **p_progress, const char *msg)
 			throughput_string(&tp->display, tp->curr_total, rate);
 		}
 		progress_update = 1;
-		buf = xstrfmt(", %s.\n", msg);
-		display(progress, progress->last_value, buf);
-		free(buf);
+		display(progress, progress->last_value, msg, 1);
 	}
 	clear_progress_signal(progress);
 	strbuf_release(&progress->counters_sb);
-- 
2.32.0.599.g3967b4fa4ac