basic/terminal-util: introduce SYSTEMD_COLORS environment variable

... to determine if color output should be enabled. If the variable is not set,
fall back to using on_tty(). Also, rewrite existing code to use
colors_enabled() where appropriate.

1 files changed, 9 insertions, 8 deletions

diff --git a/src/basic/terminal-util.h b/src/basic/terminal-util.h
index 597a0060ad..a7c96a77cb 100644
--- a/src/basic/terminal-util.h
+++ b/src/basic/terminal-util.h
@@ -79,37 +79,38 @@ unsigned lines(void);
 void columns_lines_cache_reset(int _unused_ signum);
 
 bool on_tty(void);
+bool colors_enabled(void);
 
 static inline const char *ansi_underline(void) {
-        return on_tty() ? ANSI_UNDERLINE : "";
+        return colors_enabled() ? ANSI_UNDERLINE : "";
 }
 
 static inline const char *ansi_highlight(void) {
-        return on_tty() ? ANSI_HIGHLIGHT : "";
+        return colors_enabled() ? ANSI_HIGHLIGHT : "";
 }
 
 static inline const char *ansi_highlight_underline(void) {
-        return on_tty() ? ANSI_HIGHLIGHT_UNDERLINE : "";
+        return colors_enabled() ? ANSI_HIGHLIGHT_UNDERLINE : "";
 }
 
 static inline const char *ansi_highlight_red(void) {
-        return on_tty() ? ANSI_HIGHLIGHT_RED : "";
+        return colors_enabled() ? ANSI_HIGHLIGHT_RED : "";
 }
 
 static inline const char *ansi_highlight_green(void) {
-        return on_tty() ? ANSI_HIGHLIGHT_GREEN : "";
+        return colors_enabled() ? ANSI_HIGHLIGHT_GREEN : "";
 }
 
 static inline const char *ansi_highlight_yellow(void) {
-        return on_tty() ? ANSI_HIGHLIGHT_YELLOW : "";
+        return colors_enabled() ? ANSI_HIGHLIGHT_YELLOW : "";
 }
 
 static inline const char *ansi_highlight_blue(void) {
-        return on_tty() ? ANSI_HIGHLIGHT_BLUE : "";
+        return colors_enabled() ? ANSI_HIGHLIGHT_BLUE : "";
 }
 
 static inline const char *ansi_normal(void) {
-        return on_tty() ? ANSI_NORMAL : "";
+        return colors_enabled() ? ANSI_NORMAL : "";
 }
 
 int get_ctty_devnr(pid_t pid, dev_t *d);