common progress display support

Instead of having this code duplicated in multiple places, let's have
a common interface for progress display.  If someday someone wishes to
display a cheezy progress bar instead then only one file will have to
be changed.

Note: I left merge-recursive.c out since it has a strange notion of
progress as it apparently increase the expected total number as it goes.
Someone with more intimate knowledge of what that is supposed to mean
might look at converting it to the common progress interface.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 68 insertions, 0 deletions

diff --git a/progress.c b/progress.c
new file mode 100644
index 000000000..702e11606
--- /dev/null
+++ b/progress.c
@@ -0,0 +1,68 @@
+#include "git-compat-util.h"
+#include "progress.h"
+
+static volatile sig_atomic_t progress_update;
+
+static void progress_interval(int signum)
+{
+	progress_update = 1;
+}
+
+static void set_progress_signal(void)
+{
+	struct sigaction sa;
+	struct itimerval v;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = progress_interval;
+	sigemptyset(&sa.sa_mask);
+	sa.sa_flags = SA_RESTART;
+	sigaction(SIGALRM, &sa, NULL);
+
+	v.it_interval.tv_sec = 1;
+	v.it_interval.tv_usec = 0;
+	v.it_value = v.it_interval;
+	setitimer(ITIMER_REAL, &v, NULL);
+}
+
+static void clear_progress_signal(void)
+{
+	struct itimerval v = {{0,},};
+	setitimer(ITIMER_REAL, &v, NULL);
+	signal(SIGALRM, SIG_IGN);
+	progress_update = 0;
+}
+
+int display_progress(struct progress *progress, unsigned n)
+{
+	if (progress->total) {
+		unsigned percent = n * 100 / progress->total;
+		if (percent != progress->last_percent || progress_update) {
+			progress->last_percent = percent;
+			fprintf(stderr, "%s%4u%% (%u/%u) done\r",
+				progress->msg, percent, n, progress->total);
+			progress_update = 0;
+			return 1;
+		}
+	} else if (progress_update) {
+		fprintf(stderr, "%s%u\r", progress->msg, n);
+		progress_update = 0;
+		return 1;
+	}
+	return 0;
+}
+
+void start_progress(struct progress *progress, const char *msg, unsigned total)
+{
+	progress->msg = msg;
+	progress->total = total;
+	progress->last_percent = -1;
+	set_progress_signal();
+}
+
+void stop_progress(struct progress *progress)
+{
+	clear_progress_signal();
+	if (progress->total)
+		fputc('\n', stderr);
+}