Merge branch 'lm/squelch-bg-progress'

Many long-running operations show progress eye-candy, even when
they are later backgrounded.  Hide the eye-candy when the process
is sent to the background instead.

* lm/squelch-bg-progress:
  compat/mingw: stubs for getpgid() and tcgetpgrp()
  progress: no progress in background

2 files changed, 22 insertions, 8 deletions

diff --git a/compat/mingw.h b/compat/mingw.h
index 5e499cfb71..98c5e44294 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -98,8 +98,6 @@ static inline unsigned int alarm(unsigned int seconds)
 { return 0; }
 static inline int fsync(int fd)
 { return _commit(fd); }
-static inline pid_t getppid(void)
-{ return 1; }
 static inline void sync(void)
 {}
 static inline uid_t getuid(void)
@@ -121,6 +119,12 @@ static inline int sigaddset(sigset_t *set, int signum)
 #define SIG_UNBLOCK 0
 static inline int sigprocmask(int how, const sigset_t *set, sigset_t *oldset)
 { return 0; }
+static inline pid_t getppid(void)
+{ return 1; }
+static inline pid_t getpgid(pid_t pid)
+{ return pid == 0 ? getpid() : pid; }
+static inline pid_t tcgetpgrp(int fd)
+{ return getpid(); }
 
 /*
  * simple adaptors
diff --git a/progress.c b/progress.c
index 412e6b1ecc..43d9228378 100644
--- a/progress.c
+++ b/progress.c
@@ -72,6 +72,11 @@ static void clear_progress_signal(void)
 	progress_update = 0;
 }
 
+static int is_foreground_fd(int fd)
+{
+	return getpgid(0) == tcgetpgrp(fd);
+}
+
 static int display(struct progress *progress, unsigned n, const char *done)
 {
 	const char *eol, *tp;
@@ -98,16 +103,21 @@ static int display(struct progress *progress, unsigned n, const char *done)
 		unsigned percent = n * 100 / progress->total;
 		if (percent != progress->last_percent || progress_update) {
 			progress->last_percent = percent;
-			fprintf(stderr, "%s: %3u%% (%u/%u)%s%s",
-				progress->title, percent, n,
-				progress->total, tp, eol);
-			fflush(stderr);
+			if (is_foreground_fd(fileno(stderr)) || done) {
+				fprintf(stderr, "%s: %3u%% (%u/%u)%s%s",
+					progress->title, percent, n,
+					progress->total, tp, eol);
+				fflush(stderr);
+			}
 			progress_update = 0;
 			return 1;
 		}
 	} else if (progress_update) {
-		fprintf(stderr, "%s: %u%s%s", progress->title, n, tp, eol);
-		fflush(stderr);
+		if (is_foreground_fd(fileno(stderr)) || done) {
+			fprintf(stderr, "%s: %u%s%s",
+				progress->title, n, tp, eol);
+			fflush(stderr);
+		}
 		progress_update = 0;
 		return 1;
 	}