Flesh out wayland backend somewhat, add example

common/log.c

@@ -0,0 +1,100 @@
+#define _POSIX_C_SOURCE 1
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <time.h>
+#include "wlr/common/log.h"
+#include "common/log.h"
+
+static bool colored = true;
+static log_callback_t log_callback;
+
+static const char *verbosity_colors[] = {
+	[L_SILENT] = "",
+	[L_ERROR ] = "\x1B[1;31m",
+	[L_INFO  ] = "\x1B[1;34m",
+	[L_DEBUG ] = "\x1B[1;30m",
+};
+
+void wlr_log_init(log_callback_t callback) {
+	log_callback = callback;
+	// TODO: Use log callback
+}
+
+void _wlr_vlog(const char *filename, int line, log_importance_t verbosity,
+		const char *format, va_list args) {
+	// prefix the time to the log message
+	static struct tm result;
+	static time_t t;
+	static struct tm *tm_info;
+	char buffer[26];
+
+	// get current time
+	t = time(NULL);
+	// convert time to local time (determined by the locale)
+	tm_info = localtime_r(&t, &result);
+	// generate time prefix
+	strftime(buffer, sizeof(buffer), "%x %X - ", tm_info);
+	fprintf(stderr, "%s", buffer);
+
+	unsigned int c = verbosity;
+	if (c > sizeof(verbosity_colors) / sizeof(char *) - 1) {
+		c = sizeof(verbosity_colors) / sizeof(char *) - 1;
+	}
+
+	if (colored && isatty(STDERR_FILENO)) {
+		fprintf(stderr, "%s", verbosity_colors[c]);
+	}
+
+	if (filename && line) {
+		const char *file = filename + strlen(filename);
+		while (file != filename && *file != '/') {
+			--file;
+		}
+		if (*file == '/') {
+			++file;
+		}
+		fprintf(stderr, "[%s:%d] ", file, line);
+	}
+
+	vfprintf(stderr, format, args);
+
+	if (colored && isatty(STDERR_FILENO)) {
+		fprintf(stderr, "\x1B[0m");
+	}
+	fprintf(stderr, "\n");
+}
+
+void _wlr_log(const char *filename, int line, log_importance_t verbosity, const char* format, ...) {
+	va_list args;
+	va_start(args, format);
+	_wlr_vlog(filename, line, verbosity, format, args);
+	va_end(args);
+}
+
+void wlr_log_errno(log_importance_t verbosity, char* format, ...) {
+	unsigned int c = verbosity;
+	if (c > sizeof(verbosity_colors) / sizeof(char *) - 1) {
+		c = sizeof(verbosity_colors) / sizeof(char *) - 1;
+	}
+
+	if (isatty(STDERR_FILENO)) {
+		fprintf(stderr, "%s", verbosity_colors[c]);
+	}
+
+	va_list args;
+	va_start(args, format);
+	vfprintf(stderr, format, args);
+	va_end(args);
+
+	fprintf(stderr, ": ");
+	fprintf(stderr, "%s", strerror(errno));
+
+	if (isatty(STDERR_FILENO)) {
+		fprintf(stderr, "\x1B[0m");
+	}
+	fprintf(stderr, "\n");
+}