thehub/libs/utils/LogChannels_p.h

/*
 * This file is part of the Flowee project
 * Copyright (C) 2017-2026 Tom Zander <tom@flowee.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 3 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, see <http://www.gnu.org/licenses/>.
 */
#ifndef FLOWEE_LOGCHANNELS_P_H
#define FLOWEE_LOGCHANNELS_P_H

#include "LogChannel.h"

/*
 * WARNING USAGE OF THIS HEADER IS RESTRICTED.
 * This Header file is part of the private API and is meant to be used solely by the Logger component.
 *
 * Usage of this API will likely mean your code will break in interesting ways in the future,
 * or even stop to compile.
 *
 * YOU HAVE BEEN WARNED!!
 */

#include <boost/date_time/posix_time/posix_time.hpp>
#include <boost/filesystem/path.hpp>
#include <thread>

class ConfigurableChannel : public Log::Channel
{
public:
    ConfigurableChannel(TimeStampFormat formatTimestamp);
    virtual void reopenLogFiles() {}

    bool logSection() const;
    void setLogSection(bool printSection);

    bool logLineNumber() const;
    void setLogLineNumber(bool printLineNumber);

    bool logMethodName() const;
    void setLogMethodName(bool printMethodName);

    bool logFilename() const;
    void setLogFilename(bool printFilename);

    virtual void setPath(const std::string &path) {}

protected:
    TimeStampFormat m_timeStampFormat;
    bool m_logSection;
    bool m_logLineNumber;
    bool m_logMethodName;
    bool m_logFilename;
};

class ConsoleLogChannel : public ConfigurableChannel
{
public:
    ConsoleLogChannel();

    void setPrefix(const char *prefix);
    const char *prefix() const {
        return m_prefix;
    }

    virtual void pushLog(int64_t timeMillis, std::string *timestamp, const std::string &line, const char *filename,
                         int lineNumber, const char *methodName, short logSection, short logLevel);

private:
    const char *m_prefix = nullptr;
};

class FileLogChannel : public ConfigurableChannel
{
public:
    FileLogChannel(const boost::filesystem::path &logFilename);
    ~FileLogChannel();

    virtual void pushLog(int64_t timeMillis, std::string *timestamp, const std::string &line, const char *filename,
                         int lineNumber, const char *methodName, short logSection, short logLevel);
    virtual void reopenLogFiles();

    virtual void setPath(const std::string &path);

private:
    FILE *m_fileout;
    boost::filesystem::path m_logFilename;
};

/*
 * Logging in the context of multi-threading is hard because we need a mutex
 * and we serialize all thread's messages to one by one reach the file or console.
 * Files or console block on write pretty quickly under heavy load. Making bursts
 * of logging slow the application down to a single IO constrained mutex.
 *
 * As such the idea was born to keep the IO bound operation out of operational
 * threads and use lock-less operations to just push to memory log lines and have
 * a writer thread safe that to disk.
 *
 * Logging is generally speaking in Flowee not a firehose and thus storing it in
 * memory while running is perfectly adequate for testing setups and benchmarkings.
 */
class FastLogChannel : public Log::Channel
{
public:
    FastLogChannel(const boost::filesystem::path &logFilename);
    ~FastLogChannel();

public:
    void pushLog(int64_t timeMillis, std::string *timestamp, const std::string &line, const char *filename, int lineNumber, const char *methodName, short logSection, short logLevel) override;

    struct Item {
        Item() : next(0) {}
        std::atomic<Item*> next;
        int64_t timeMillis;
        std::string line;
        const char *filename;
        const char *methodname;
        int lineNumber;
        short logSection;
        short logLevel;
        std::thread::id callingThread;
    };

private:
    std::unique_ptr<std::thread> m_writeThread;
    std::atomic<Item*> m_writePtr;
};

#endif