Start fleshing out wayland client implementation

This introduces a basic shared framework for making wayland clients
within sway itself.

common/log.c

@@ -0,0 +1,159 @@
+#include "log.h"
+#include "sway.h"
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <libgen.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <signal.h>
+#include <errno.h>
+#include <string.h>
+#include <stringop.h>
+#include <execinfo.h>
+
+int colored = 1;
+log_importance_t loglevel_default = L_ERROR;
+log_importance_t v = L_SILENT;
+
+static const char *verbosity_colors[] = {
+	[L_SILENT] = "",
+	[L_ERROR ] = "\x1B[1;31m",
+	[L_INFO  ] = "\x1B[1;34m",
+	[L_DEBUG ] = "\x1B[1;30m",
+};
+
+void init_log(log_importance_t verbosity) {
+	if (verbosity != L_DEBUG) {
+		// command "debuglog" needs to know the user specified log level when
+		// turning off debug logging.
+		loglevel_default = verbosity;
+	}
+	v = verbosity;
+	signal(SIGSEGV, error_handler);
+	signal(SIGABRT, error_handler);
+}
+
+void set_log_level(log_importance_t verbosity) {
+	v = verbosity;
+}
+
+void reset_log_level(void) {
+	v = loglevel_default;
+}
+
+bool toggle_debug_logging(void) {
+	v = (v == L_DEBUG) ? loglevel_default : L_DEBUG;
+	return (v == L_DEBUG);
+}
+
+void sway_log_colors(int mode) {
+	colored = (mode == 1) ? 1 : 0;
+}
+
+void sway_abort(const char *format, ...) {
+	fprintf(stderr, "ERROR: ");
+	va_list args;
+	va_start(args, format);
+	vfprintf(stderr, format, args);
+	va_end(args);
+	fprintf(stderr, "\n");
+	sway_terminate();
+}
+
+#ifndef NDEBUG
+void _sway_log(const char *filename, int line, log_importance_t verbosity, const char* format, ...) {
+#else
+void _sway_log(log_importance_t verbosity, const char* format, ...) {
+#endif
+	if (verbosity <= v) {
+		unsigned int c = verbosity;
+		if (c > sizeof(verbosity_colors) / sizeof(char *)) {
+			c = sizeof(verbosity_colors) / sizeof(char *) - 1;
+		}
+
+		if (colored && isatty(STDERR_FILENO)) {
+			fprintf(stderr, "%s", verbosity_colors[c]);
+		}
+
+		va_list args;
+		va_start(args, format);
+#ifndef NDEBUG
+		char *file = strdup(filename);
+		fprintf(stderr, "[%s:%d] ", basename(file), line);
+		free(file);
+#endif
+		vfprintf(stderr, format, args);
+		va_end(args);
+
+		if (colored && isatty(STDERR_FILENO)) {
+			fprintf(stderr, "\x1B[0m");
+		}
+		fprintf(stderr, "\n");
+	}
+}
+
+void sway_log_errno(log_importance_t verbosity, char* format, ...) {
+	if (verbosity <= v) {
+		unsigned int c = verbosity;
+		if (c > sizeof(verbosity_colors) / sizeof(char *)) {
+			c = sizeof(verbosity_colors) / sizeof(char *) - 1;
+		}
+
+		if (colored && 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 (colored && isatty(STDERR_FILENO)) {
+			fprintf(stderr, "\x1B[0m");
+		}
+		fprintf(stderr, "\n");
+	}
+}
+
+bool _sway_assert(bool condition, const char* format, ...) {
+	if (condition) {
+		return true;
+	}
+
+	va_list args;
+	va_start(args, format);
+	sway_log(L_ERROR, format, args);
+	va_end(args);
+
+#ifndef NDEBUG
+	raise(SIGABRT);
+#endif
+
+	return false;
+}
+
+void error_handler(int sig) {
+	int i;
+	int max_lines = 20;
+	void *array[max_lines];
+	char **bt;
+	size_t bt_len;
+
+	sway_log(L_ERROR, "Error: Signal %d. Printing backtrace", sig);
+	bt_len = backtrace(array, max_lines);
+	bt = backtrace_symbols(array, bt_len);
+	if (!bt) {
+		sway_log(L_ERROR, "Could not allocate sufficient memory for backtrace_symbols(), falling back to stderr");
+		backtrace_symbols_fd(array, bt_len, STDERR_FILENO);
+		exit(1);
+	}
+
+	for (i = 0; (size_t)i < bt_len; i++) {
+		sway_log(L_ERROR, "Backtrace: %s", bt[i]);
+	}
+	exit(1);
+}