Extract logger into own header

src/diagnostic_logger.cpp

@@ -0,0 +1,40 @@
+// Copyright (C) 2017 Jonathan Müller <jonathanmueller.dev@gmail.com>
+// This file is subject to the license terms in the LICENSE file
+// found in the top-level directory of this distribution.
+
+#include <cppast/diagnostic_logger.hpp>
+
+#include <cstdio>
+#include <mutex>
+
+using namespace cppast;
+
+bool diagnostic_logger::log(const char* source, const diagnostic& d) const
+{
+    if (!verbose_ && d.severity == severity::debug)
+        return false;
+    return do_log(source, d);
+}
+
+type_safe::object_ref<const diagnostic_logger> cppast::default_logger() noexcept
+{
+    static const stderr_diagnostic_logger logger(false);
+    return type_safe::ref(logger);
+}
+
+type_safe::object_ref<const diagnostic_logger> cppast::default_verbose_logger() noexcept
+{
+    static const stderr_diagnostic_logger logger(true);
+    return type_safe::ref(logger);
+}
+
+bool stderr_diagnostic_logger::do_log(const char* source, const diagnostic& d) const
+{
+    auto loc = d.location.to_string();
+    if (loc.empty())
+        std::fprintf(stderr, "[%s] [%s] %s\n", source, to_string(d.severity), d.message.c_str());
+    else
+        std::fprintf(stderr, "[%s] [%s] %s %s\n", source, to_string(d.severity),
+                     d.location.to_string().c_str(), d.message.c_str());
+    return true;
+}