logging abstraction

log.hpp

//
//  main.cpp
//  test
//
//  Created by Ilia Choly on 12-11-20.
//  Copyright (c) 2012 Ilia Choly. All rights reserved.
//

#include <iostream>
#include <functional>

#define ACCIPITER_LOGGING_ENABLED

namespace logging {
    
    struct Logger {
        inline void error (char const* msg) {
            std::cerr << msg << std::flush;
        }
    };
    
    namespace {
    
        struct Singleton {
            static Logger logger;
        };
        
        struct Sink {
            
            virtual inline void message (char const*) = 0;
            
            inline Sink & operator<< (std::string const& msg) {
                #ifdef ACCIPITER_LOGGING_ENABLED
                message(msg.c_str());
                return *this;
                #endif
            }
            
            inline Sink & operator<< (char c) {
                #ifdef ACCIPITER_LOGGING_ENABLED
                message(std::string(1, c).c_str());
                return *this;
                #endif
            }
            
        };
        
        struct ErrorSink : public Sink {
            inline void message (char const* msg) {
                Singleton::logger.error(msg);
            }
        };
        
    }
    
    struct log {
        
        enum {
            endl = '\n',
            tab  = '\t'
        };
        
        static ErrorSink error;
    };
    
    ErrorSink log::error;
    Logger Singleton::logger;
}

using ::logging::log;

int main() {
    log::error << "this is a test" << log::endl;
    return 0;
}