Logging.h

/*
 *  Phusion Passenger - http://www.modrails.com/
 *  Copyright (C) 2008  Phusion
 *
 *  Phusion Passenger is a trademark of Hongli Lai & Ninh Bui.
 *
 *  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; version 2 of the License.
 *
 *  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.
 */
#ifndef _PASSENGER_LOGGING_H_
#define _PASSENGER_LOGGING_H_

#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#include <ostream>
#include <sstream>
#include <ctime>

namespace Passenger {

using namespace std;

extern unsigned int _logLevel;
extern ostream *_logStream;
extern ostream *_debugStream;

unsigned int getLogLevel();
void setLogLevel(unsigned int value);
void setDebugFile(const char *logFile = NULL);

/**
 * Write the given expression to the given stream.
 *
 * @param expr The expression to write.
 * @param stream A pointer to an object that accepts the '<<' operator.
 */
#define P_LOG_TO(expr, stream) \
        do { \
                if (stream != 0) { \
                        time_t the_time;                        \
                        struct tm *the_tm;                      \
                        char datetime_buf[60];                  \
                        struct timeval tv;                      \
                        std::stringstream sstream;              \
                                                                \
                        the_time = time(NULL);                  \
                        the_tm = localtime(&the_time);          \
                        strftime(datetime_buf, sizeof(datetime_buf), "%F %H:%M:%S", the_tm); \
                        gettimeofday(&tv, NULL); \
                        sstream << \
                                "[ pid=" << getpid() << " file=" << __FILE__ << ":" << __LINE__ << \
                                " time=" << datetime_buf << "." << (tv.tv_usec / 1000) << " ]:" << \
                                "\n  " << expr << std::endl;    \
                        *stream << sstream.str();               \
                        stream->flush();                        \
                } \
        } while (false)

/**
 * Write the given expression to the log stream.
 */
#define P_LOG(expr) P_LOG_TO(expr, Passenger::_logStream)

/**
 * Write the given expression, which represents a warning,
 * to the log stream.
 */
#define P_WARN(expr) P_LOG(expr)

/**
 * Write the given expression, which represents an error,
 * to the log stream.
 */
#define P_ERROR(expr) P_LOG(expr)

/**
 * Write the given expression, which represents a debugging message,
 * to the log stream.
 */
#define P_DEBUG(expr) P_TRACE(1, expr)

#ifdef PASSENGER_DEBUG
        #define P_TRACE(level, expr) \
                do { \
                        if (Passenger::_logLevel >= level) { \
                                P_LOG_TO(expr, Passenger::_debugStream); \
                        } \
                } while (false)
        
        #define P_ASSERT(expr, result_if_failed, message) \
                do { \
                        if (!(expr)) { \
                                P_ERROR("Assertion failed: " << message); \
                                return result_if_failed; \
                        } \
                } while (false)
#else
        #define P_TRACE(level, expr) do { /* nothing */ } while (false)
        
        #define P_ASSERT(expr, result_if_failed, message) do { /* nothing */ } while (false)
#endif

} // namespace Passenger

#endif /* _PASSENGER_LOGGING_H_ */

---