u/logging: Implement optional color logging.

Check if stderr is a tty.

CMakeLists.txt

@@ -115,6 +115,8 @@ endif()
 # This one is named differently because that's what CTest uses
 option(BUILD_TESTING "Enable building of the test suite?" ON)
 
+option(XRT_FEATURE_COLOR_LOG "Enable logging in color on supported platforms" ON)
+
 cmake_dependent_option(CMAKE_INTERPROCEDURAL_OPTIMIZATION "Enable inter-procedural (link-time) optimization" OFF "HAS_IPO" OFF)
 cmake_dependent_option(XRT_HAVE_WAYLAND "Enable Wayland support" ON "WAYLAND_FOUND AND WAYLAND_SCANNER_FOUND AND WAYLAND_PROTOCOLS_FOUND" OFF)
 cmake_dependent_option(XRT_HAVE_XLIB "Enable xlib support" ON "X11_FOUND" OFF)

meson_options.txt

@@ -114,3 +114,8 @@ option('steamvr_plugin',
 	description: 'Enable SteamVR Plugin'
 )
 
+option('color_log',
+	type: 'boolean',
+	value: true,
+	description: 'Log in color'
+)

src/xrt/auxiliary/util/u_logging.c

@@ -9,6 +9,7 @@
 
 #include "util/u_logging.h"
 #include "xrt/xrt_config_os.h"
+#include "xrt/xrt_config_build.h"
 
 #include <assert.h>
 #include <stdio.h>
@@ -149,14 +150,51 @@ u_log_xdev(const char *file,
 
 
 #else
+
+#include <unistd.h>
+
 /*
  *
  * Helper functions.
  *
  */
 
+
+#ifdef XRT_FEATURE_COLOR_LOG
+#define COLOR_TRACE "\033[2m"
+#define COLOR_DEBUG "\033[36m"
+#define COLOR_INFO "\033[32m"
+#define COLOR_WARN "\033[33m"
+#define COLOR_ERROR "\033[31m"
+#define COLOR_RESET "\033[0m"
+
 static void
-print_prefix(const char *func, enum u_logging_level level)
+print_prefix_color(const char *func, enum u_logging_level level)
+{
+	switch (level) {
+	case U_LOGGING_TRACE:
+		fprintf(stderr, COLOR_TRACE "TRACE " COLOR_RESET);
+		break;
+	case U_LOGGING_DEBUG:
+		fprintf(stderr, COLOR_DEBUG "DEBUG " COLOR_RESET);
+		break;
+	case U_LOGGING_INFO:
+		fprintf(stderr, COLOR_INFO " INFO " COLOR_RESET);
+		break;
+	case U_LOGGING_WARN:
+		fprintf(stderr, COLOR_WARN " WARN " COLOR_RESET);
+		break;
+	case U_LOGGING_ERROR:
+		fprintf(stderr, COLOR_ERROR "ERROR " COLOR_RESET);
+		break;
+	case U_LOGGING_RAW: break;
+	default: break;
+	}
+}
+#endif
+
+static void
+print_prefix_mono(const char *func, enum u_logging_level level)
 {
 	switch (level) {
 	case U_LOGGING_TRACE: fprintf(stderr, "TRACE "); break;
@@ -167,6 +205,20 @@ print_prefix(const char *func, enum u_logging_level level)
 	case U_LOGGING_RAW: break;
 	default: break;
 	}
+}
+
+static void
+print_prefix(const char *func, enum u_logging_level level)
+{
+#ifdef XRT_FEATURE_COLOR_LOG
+	if (isatty(STDERR_FILENO)) {
+		print_prefix_color(func, level);
+	} else {
+		print_prefix_mono(func, level);
+	}
+#else
+	print_prefix_mono(func, level);
+#endif
 
 	if (level != U_LOGGING_RAW && func != NULL) {
 		fprintf(stderr, "[%s] ", func);

src/xrt/include/xrt/meson.build

@@ -121,6 +121,10 @@ if get_option('service')
 	build_conf.set('XRT_FEATURE_SERVICE', true)
 endif
 
+if get_option('color_log')
+	build_conf.set('XRT_FEATURE_COLOR_LOG', true)
+endif
+
 xrt_config_build_h = configure_file(
 	output: 'xrt_config_build.h',
 	configuration: build_conf,

src/xrt/include/xrt/xrt_config_build.h.cmake_in

@@ -24,3 +24,5 @@
 #cmakedefine XRT_FEATURE_OPENXR_LAYER_EQUIRECT2
 
 #cmakedefine XRT_FEATURE_OPENXR_LAYER_EQUIRECT1
+
+#cmakedefine XRT_FEATURE_COLOR_LOG