Log: move Log() to LogBackend.cxx

Prepare for GLib removal.

src/LogBackend.cxx

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2003-2013 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "Log.hxx"
+#include "util/Domain.hxx"
+
+#include <glib.h>
+
+#include <assert.h>
+
+static GLogLevelFlags
+ToGLib(LogLevel level)
+{
+	switch (level) {
+	case LogLevel::DEBUG:
+		return G_LOG_LEVEL_DEBUG;
+
+	case LogLevel::INFO:
+		return G_LOG_LEVEL_INFO;
+
+	case LogLevel::DEFAULT:
+		return G_LOG_LEVEL_MESSAGE;
+
+	case LogLevel::WARNING:
+	case LogLevel::ERROR:
+		return G_LOG_LEVEL_WARNING;
+	}
+
+	assert(false);
+	gcc_unreachable();
+}
+
+void
+Log(const Domain &domain, LogLevel level, const char *msg)
+{
+	g_log(domain.GetName(), ToGLib(level), "%s", msg);
+}