[PATCH 22/25] progress.c: add a stop_progress_early() function

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

In cases where we error out during processing or otherwise miss
initial "total" estimate we'll still want to show a "done" message and
end our trace2 region, but it won't be true that our total ==
last_update at the end.

So let's add a "last_update" and this stop_progress_early() function
to handle that edge case, this will be used in a subsequent commit.

We could also use a total=0 in such cases, but that would make the
progress output worse for the common non-erroring case. Let's instead
note that we didn't reach the total count, and snap the progress bar
to "100%, done" at the end.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 progress.c | 20 ++++++++++++++++++++
 progress.h |  2 ++
 2 files changed, 22 insertions(+)

diff --git a/progress.c b/progress.c
index 35847d3a7f2..c1cb01ba975 100644
--- a/progress.c
+++ b/progress.c
@@ -40,6 +40,8 @@ static void display(struct progress *progress, uint64_t n,
 	const char *tp;
 	int show_update = 0;
 
+	progress->last_update = n;
+
 	if (progress->delay && (!progress_update || --progress->delay))
 		return;
 
@@ -413,3 +415,21 @@ void stop_progress_msg(struct progress **p_progress, const char *msg)
 	free(progress->throughput);
 	free(progress);
 }
+
+void stop_progress_early(struct progress **p_progress)
+{
+	struct progress *progress;
+	struct strbuf sb = STRBUF_INIT;
+
+	if (!p_progress)
+		BUG("don't provide NULL to stop_progress_early");
+	progress = *p_progress;
+	if (!progress)
+		return;
+
+	strbuf_addf(&sb, _(", done at %"PRIuMAX" items, expected %"PRIuMAX"."),
+		    progress->total, progress->last_update);
+	progress->total = progress->last_update;
+	stop_progress_msg(p_progress, sb.buf);
+	strbuf_release(&sb);
+}
diff --git a/progress.h b/progress.h
index ba38447d104..5c5d027d1a0 100644
--- a/progress.h
+++ b/progress.h
@@ -23,6 +23,7 @@ struct progress {
 	struct strbuf status;
 	size_t status_len_utf8;
 
+	uint64_t last_update;
 	uint64_t last_value;
 	uint64_t total;
 	unsigned last_percent;
@@ -56,5 +57,6 @@ struct progress *start_delayed_sparse_progress(const char *title,
 					       uint64_t total);
 void stop_progress(struct progress **progress);
 void stop_progress_msg(struct progress **progress, const char *msg);
+void stop_progress_early(struct progress **p_progress);
 
 #endif
-- 
2.32.0.599.g3967b4fa4ac