native_posix: Add control of traces color

For native_posix:
Added command line options to control if traces should have
or not colors.
+
Detect if we are connected to a tty or not, and if we are
set the defaults for that option appropriately

Signed-off-by: Alberto Escolar Piedras <alpi@oticon.com>

arch/posix/include/posix_trace.h

@@ -13,6 +13,19 @@ extern "C" {
 void posix_print_error_and_exit(const char *format, ...);
 void posix_print_warning(const char *format, ...);
 void posix_print_trace(const char *format, ...);
+/**
+ * Return 1 if traces to <output> will go to a tty.
+ * When printing to a terminal we may use ASCII escapes for color or other
+ * niceties.
+ * But when redirecting to files, or piping to other commands, those should be
+ * disabled by default.
+ *
+ * Where the <output> should be set to 0 to query about posix_print_trace output
+ * (typically STDOUT)
+ * and 1 to query about the warning and error output (posix_print_error/warning)
+ * outputs (typically STDERR)
+ */
+int posix_trace_over_tty(int output);
 
 #ifdef __cplusplus
 }

boards/posix/native_posix/cmdline.c

@@ -14,6 +14,7 @@
 #include "cmdline.h"
 #include "toolchain.h"
 #include "posix_trace.h"
+#include "native_tracing.h"
 
 static int s_argc, test_argc;
 static char **s_argv, **test_argv;
@@ -89,7 +90,6 @@ void native_add_testargs_option(void)
 		(void *)NULL, NULL,
 		"Any argument that follows will be ignored by the top level, "
 		"and made available for possible tests"},
-
 		ARG_TABLE_ENDMARKER};
 
 	native_add_command_line_opts(testargs_options);
@@ -104,6 +104,7 @@ void native_handle_cmd_line(int argc, char *argv[])
 {
 	int i;
 
+	native_add_tracing_options();
 	native_add_testargs_option();
 
 	s_argv = argv;

boards/posix/native_posix/native_tracing.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2018 Oticon A/S
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef NATIVE_TRACING_H
+#define NATIVE_TRACING_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void native_add_tracing_options(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NATIVE_TRACING_H */

boards/posix/native_posix/tracing.c

@@ -11,9 +11,10 @@
 #include <stdlib.h> /* for exit */
 #include <stdio.h>  /* for printfs */
 #include <stdarg.h> /* for va args */
-
+#include <unistd.h>
+#include "soc.h"
 #include "posix_board_if.h"
-
+#include "cmdline.h"
 
 void posix_print_error_and_exit(const char *format, ...)
 {
@@ -42,3 +43,75 @@ void posix_print_trace(const char *format, ...)
 	vfprintf(stdout, format, variable_args);
 	va_end(variable_args);
 }
+
+/**
+ * Are stdout and stderr connectd to a tty
+ * 0  = no
+ * 1  = yes
+ * -1 = we do not know yet
+ * Indexed 0:stdout, 1:stderr
+ */
+static int is_a_tty[2] = {-1, -1};
+
+void trace_disable_color(char *argv, int offset)
+{
+	is_a_tty[0] = 0;
+	is_a_tty[1] = 0;
+}
+
+void trace_enable_color(char *argv, int offset)
+{
+	is_a_tty[0] = -1;
+	is_a_tty[1] = -1;
+
+}
+
+void trace_force_color(char *argv, int offset)
+{
+	is_a_tty[0] = 1;
+	is_a_tty[1] = 1;
+}
+
+int posix_trace_over_tty(int file_number)
+{
+	return is_a_tty[file_number];
+}
+
+static void decide_about_color(void)
+{
+	if (is_a_tty[0] == -1) {
+		is_a_tty[0] = isatty(STDOUT_FILENO);
+	}
+	if (is_a_tty[1] == -1) {
+		is_a_tty[1] = isatty(STDERR_FILENO);
+	}
+}
+
+NATIVE_TASK(decide_about_color, PRE_BOOT_2, 0);
+
+void native_add_tracing_options(void)
+{
+	static struct args_struct_t trace_options[] = {
+		/*
+		 * Fields:
+		 * manual, mandatory, switch,
+		 * option_name, var_name ,type,
+		 * destination, callback,
+		 * description
+		 */
+		{ false, false, true,
+		"color", "color", 'b',
+		NULL, trace_enable_color,
+		"(default) Enable color in traces if printing to console"},
+		{ false, false, true,
+		"no-color", "no-color", 'b',
+		NULL, trace_disable_color,
+		"Disable color in traces even if printing to console"},
+		{ false, false, true,
+		"force-color", "force-color", 'b',
+		NULL, trace_force_color,
+		"Enable color in traces even if printing to files/pipes"},
+		ARG_TABLE_ENDMARKER};
+
+	native_add_command_line_opts(trace_options);
+}