lib/colors: add support for auto, always and never modes

 ... to implement --color[=<when>]

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 72 insertions, 2 deletions

diff --git a/lib/colors.c b/lib/colors.c
index 6af038b31..57ecae93d 100644
--- a/lib/colors.c
+++ b/lib/colors.c
@@ -4,14 +4,26 @@
  * This file may be distributed under the terms of the
  * GNU Lesser General Public License.
  */
+#include <c.h>
+#include <assert.h>
 
 #include "colors.h"
 
 static int ul_color_term_ok;
 
-int colors_init(void)
+int colors_init(int mode)
 {
-	ul_color_term_ok = isatty(STDOUT_FILENO);
+	switch (mode) {
+	case UL_COLORMODE_AUTO:
+		ul_color_term_ok = isatty(STDOUT_FILENO);
+		break;
+	case UL_COLORMODE_ALWAYS:
+		ul_color_term_ok = 1;
+		break;
+	case UL_COLORMODE_NEVER:
+	default:
+		ul_color_term_ok = 0;
+	}
 	return ul_color_term_ok;
 }
 
@@ -26,3 +38,61 @@ void color_disable(void)
 	if (ul_color_term_ok)
 		fputs(UL_COLOR_RESET, stdout);
 }
+
+int colormode_from_string(const char *str)
+{
+	size_t i;
+	static const char *modes[] = {
+		[UL_COLORMODE_AUTO]   = "auto",
+		[UL_COLORMODE_NEVER]  = "never",
+		[UL_COLORMODE_ALWAYS] = "always"
+	};
+
+	if (!str || !*str)
+		return -EINVAL;
+
+	assert(ARRAY_SIZE(modes) == __UL_NCOLORMODES);
+
+	for (i = 0; i < ARRAY_SIZE(modes); i++) {
+		if (strcasecmp(str, modes[i]) == 0)
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+#ifdef TEST_PROGRAM
+# include <getopt.h>
+# include <err.h>
+
+int main(int argc, char *argv[])
+{
+	static const struct option longopts[] = {
+		{ "colors", optional_argument, 0, 'c' },
+		{ NULL, 0, 0, 0 }
+	};
+	int c, mode = UL_COLORMODE_NEVER;	/* default */
+
+	while ((c = getopt_long(argc, argv, "c::", longopts, NULL)) != -1) {
+		switch (c) {
+		case 'c':
+			mode = UL_COLORMODE_AUTO;
+			if (optarg) {
+				char *p = *optarg == '=' ? optarg + 1 : optarg;
+
+				mode = colormode_from_string(p);
+				if (mode < 0)
+					errx(EXIT_FAILURE, "'%s' unsupported color mode", p);
+			}
+			break;
+		}
+	}
+
+	colors_init(mode);
+	color_enable(UL_COLOR_RED);
+	printf("Hello World!");
+	color_disable();
+	return EXIT_SUCCESS;
+}
+#endif
+