log_internal.h

#ifndef __ASHUFFLE_LOG_INTERNAL_H__
#define __ASHUFFLE_LOG_INTERNAL_H__

#include <cassert>
#include <fstream>
#include <iostream>

#include <absl/strings/str_format.h>

namespace ashuffle {
namespace log {

struct SourceLocation final {
    SourceLocation(const std::string_view file = __builtin_FILE(),
                   const std::string_view function = __builtin_FUNCTION(),
                   unsigned line = __builtin_LINE())
        : file(file), function(function), line(line) {}

    const std::string_view file;
    const std::string_view function;
    const unsigned line;
};

std::ostream& operator<<(std::ostream&, const SourceLocation&);

// Logger is an object that owns the output file and standard formatting
// for logs.
class Logger final {
   public:
    Logger(){};

    void SetOutput(std::ostream& output) { output_ = &output; }

    std::ostream& Stream() {
        static std::ofstream devnull("/dev/null");
        if (output_ != nullptr) {
            return *output_;
        }
        return devnull;
    }

   private:
    std::ostream* output_;
};

// Fetch the default logger.
Logger& DefaultLogger();

}  // namespace log
}  // namespace ashuffle

#endif  // __ASHUFFLE_LOG_INTERNAL_H__