log, macros: Make `stdout`, and `stderr` logging more colourful

This is designed to make it more readable when printing the logs to
a terminal, or terminal emulator.

2 files changed, 58 insertions, 2 deletions

diff --git a/log.c b/log.c
index 779fa4b..e1e71fc 100644
--- a/log.c
+++ b/log.c
@@ -4,8 +4,61 @@
 #include <string.h>
 #include <syslog.h>
 #include "log.h"
+#include "macros.h"
 #include "misc.h"
 
+typedef enum colour colour;
+
+enum colour {
+	BLACK,
+	RED,
+	GREEN,
+	YELLOW,
+	BLUE,
+	MAGENTA,
+	CYAN,
+	WHITE,
+	NUM_COLOURS,
+	RESET = NUM_COLOURS,
+};
+
+static const char *print_ansi_colour(colour colour, int is_bg, int is_bright) {
+	if (colour < NUM_COLOURS) {
+		static char str[const_strlen("\x1B[100m")+1] = {0};
+		int colour_code = colour + 30;
+
+		if (is_bg) {
+			colour_code += 10;
+		}
+
+		if (is_bright) {
+			colour_code += 60;
+		}
+
+		snprintf(str, sizeof(str)-1, "\x1B[%dm", colour_code);
+		return str;
+	} else {
+		return "\x1B[0m";
+	}
+}
+
+static const char *print_priority_colour(int priority) {
+	colour colour = RESET;
+	int is_bg = 0;
+	int is_bright = 0;
+
+	switch (priority) {
+		case LOG_ERR	: colour = RED; break;
+		case LOG_WARNING: colour = YELLOW; is_bright = 1; break;
+		case LOG_NOTICE	: colour = CYAN; break;
+		case LOG_INFO	: colour = MAGENTA; break;
+		case LOG_DEBUG	: colour = GREEN; break;
+		default		: break;
+	}
+
+	return print_ansi_colour(colour, is_bg, is_bright);
+}
+
 void vprintlog(log_output output_type, int priority, const char *fmt, va_list args) {
 	char *buf = calloc(vformat_len_copy(fmt, args)+1, sizeof(char));
 	vsprintf(buf, fmt, args);
@@ -18,7 +71,7 @@ void vprintlog(log_output output_type, int priority, const char *fmt, va_list ar
 		case LOG_OUT_STDERR:
 		case LOG_OUT_STDOUT: {
 			FILE *output = (output_type == LOG_OUT_STDOUT) ? stdout : stderr;
-			fprintf(output, "%s\n", buf);
+			fprintf(output, "%s%s\x1B[0m\n", print_priority_colour(priority), buf);
 			break;
 		}
 		default:
diff --git a/macros.h b/macros.h
index 56c8ccc..2be1d6b 100644
--- a/macros.h
+++ b/macros.h
@@ -1,10 +1,13 @@
 #ifndef MACROS_H
 #define MACROS_H
 
+#define const_strlen(str) sizeof((char []){str})
+
+#ifndef LOG_H
 #include "log.h"
 
 #define log(priority, ...) printlog(LOG_OUT_SYSLOG, priority, __VA_ARGS__)
 #define log_reason(priority, msg, ...) log(priority, msg " Reason %s", __VA_ARGS__)
-#define const_strlen(str) sizeof((char []){str})
+#endif
 
 #endif