spdlog/include/spdlog/logger.h

//
// Copyright(c) 2015-2108 Gabi Melman.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)
//

#pragma once

// Thread safe logger (except for set_pattern(..), set_formatter(..) and
// set_error_handler())
// Has name, log level, vector of std::shared sink pointers and formatter
// Upon each log write the logger:
// 1. Checks if its log level is enough to log the message and if yes:
// 2. Call the underlying sinks to do the job.
// 3. Each sink use its own private copy of a formatter to format the message
// and send to its destination.
//
// The use of private formatter per sink provides the opportunity to cache some
// formatted data,
// and support customize format per each sink.

#include "spdlog/common.h"
#include "spdlog/formatter.h"
#include "spdlog/sinks/sink.h"
#include "spdlog/details/fmt_helper.h"

#include <memory>
#include <string>
#include <vector>

#ifndef SPDLOG_CATCH_AND_HANDLE

#define SPDLOG_CATCH_AND_HANDLE                                                                                                            \
    catch (const std::exception &ex)                                                                                                       \
    {                                                                                                                                      \
        err_handler_(ex.what());                                                                                                           \
    }                                                                                                                                      \
    catch (...)                                                                                                                            \
    {                                                                                                                                      \
        err_handler_("Unknown exception in logger");                                                                                       \
    }

#endif // ! SPDLOG_CATCH_AND_HANDLE


namespace spdlog {

class logger
{
public:
    
    template<typename It>
    logger(std::string name, It begin, It end)
        : name_(std::move(name))
        , sinks_(begin, end)
    {}

	logger(std::string name, sink_ptr single_sink)
        : logger(std::move(name), {std::move(single_sink)})
    {}
    logger(std::string name, sinks_init_list sinks) : 
		logger(std::move(name), sinks.begin(), sinks.end())
	{}

    virtual ~logger() = default;

    logger(const logger &) = delete;
    logger &operator=(const logger &) = delete;

	template<typename... Args>
    void log(source_loc loc, level::level_enum lvl, const char *fmt, const Args &... args)
	{
        if (!should_log(lvl))
        {
            return;
        }

        try
        {
            using details::fmt_helper::to_string_view;
            fmt::memory_buffer buf;
            fmt::format_to(buf, fmt, args...);
            details::log_msg log_msg(loc, &name_, lvl, to_string_view(buf));
            sink_it_(log_msg);
        }
        SPDLOG_CATCH_AND_HANDLE
	}

    template<typename... Args>
	void log(level::level_enum lvl, const char *fmt, const Args &... args)
	{
        log(source_loc{}, lvl, fmt, args...);
	}

   
	void log(source_loc loc, level::level_enum lvl, const char *msg)
    {
        if (!should_log(lvl))
        {
            return;
        }

        try
        {
            details::log_msg log_msg(loc, &name_, lvl, spdlog::string_view_t(msg));
            sink_it_(log_msg);
        }
        SPDLOG_CATCH_AND_HANDLE
    }

    void log(level::level_enum lvl, const char *msg)
    {
        log(source_loc{}, lvl, msg);
    }

    

    template<typename... Args>
    void trace(const char *fmt, const Args &... args)
    {
        log(level::trace, fmt, args...);
    }


    template<typename... Args>
    void debug(const char *fmt, const Args &... args)
    {
        log(level::debug, fmt, args...);
    }


    template<typename... Args>
    void info(const char *fmt, const Args &... args)
    {
        log(level::info, fmt, args...);
    }

    template<typename... Args>
    void warn(const char *fmt, const Args &... args)
    {
        log(level::warn, fmt, args...);
    }

    template<typename... Args>
    void error(const char *fmt, const Args &... args)
    {
        log(level::err, fmt, args...);
    }

    template<typename... Args>
    void critical(const char *fmt, const Args &... args)
    {
        log(level::critical, fmt, args...);
    }


#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
#ifndef _WIN32
#error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
#else
    inline void wbuf_to_utf8buf(const fmt::wmemory_buffer &wbuf, fmt::memory_buffer &target)
    {
        int wbuf_size = static_cast<int>(wbuf.size());
        if (wbuf_size == 0)
        {
            return;
        }

        auto result_size = ::WideCharToMultiByte(CP_UTF8, 0, wbuf.data(), wbuf_size, NULL, 0, NULL, NULL);

        if (result_size > 0)
        {
            target.resize(result_size);
            ::WideCharToMultiByte(CP_UTF8, 0, wbuf.data(), wbuf_size, &target.data()[0], result_size, NULL, NULL);
        }
        else
        {
            throw spdlog::spdlog_ex(fmt::format("WideCharToMultiByte failed. Last error: {}", ::GetLastError()));
        }
    }

	template<typename... Args>
    void log(source_loc source, level::level_enum lvl, const wchar_t *fmt, const Args &... args)
    {
        if (!should_log(lvl))
        {
            return;
        }

        try
        {
            // format to wmemory_buffer and convert to utf8
            using details::fmt_helper::to_string_view;
            fmt::wmemory_buffer wbuf;
            fmt::format_to(wbuf, fmt, args...);
            fmt::memory_buffer buf;
            wbuf_to_utf8buf(wbuf, buf);
            details::log_msg log_msg(source, &name_, lvl, to_string_view(buf));
            sink_it_(log_msg);
        }
        SPDLOG_CATCH_AND_HANDLE
    }

    template<typename... Args>
    void log(level::level_enum lvl, const wchar_t *fmt, const Args &... args)
    {
        log(source_loc{}, lvl, fmt, args...);
    }
  
    template<typename... Args>
    void trace(const wchar_t *fmt, const Args &... args)
    {
        log(level::trace, fmt, args...);
    }

    template<typename... Args>
    void debug(const wchar_t *fmt, const Args &... args)
    {
        log(level::debug, fmt, args...);
    }

    template<typename... Args>
    void info(const wchar_t *fmt, const Args &... args)
    {
        log(level::info, fmt, args...);
    }

    template<typename... Args>
    void warn(const wchar_t *fmt, const Args &... args)
    {
        log(level::warn, fmt, args...);
    }

    template<typename... Args>
    void error(const wchar_t *fmt, const Args &... args)
    {
        log(level::err, fmt, args...);
    }

    template<typename... Args>
    void critical(const wchar_t *fmt, const Args &... args)
    {
        log(level::critical, fmt, args...);
    }
#endif // _WIN32
#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT

    template<typename T>
    void log(level::level_enum lvl, const T &msg)
    {
        log(source_loc{}, lvl, msg);
    }

    // T can be statically converted to string_view
    template<class T, typename std::enable_if<std::is_convertible<T, spdlog::string_view_t>::value, T>::type * = nullptr>
    void log(source_loc loc, level::level_enum lvl, const T &msg)
    {
        if (!should_log(lvl))
        {
            return;
        }
        try
        {
            details::log_msg log_msg(loc, &name_, lvl, msg);
            sink_it_(log_msg);
        }
        SPDLOG_CATCH_AND_HANDLE
    }

    // T cannot be statically converted to string_view
    template<class T, typename std::enable_if<!std::is_convertible<T, spdlog::string_view_t>::value, T>::type * = nullptr>
    void log(source_loc loc, level::level_enum lvl, const T &msg)
    {
        if (!should_log(lvl))
        {
            return;
        }
        try
        {
            using details::fmt_helper::to_string_view;
            fmt::memory_buffer buf;
            fmt::format_to(buf, "{}", msg);
            details::log_msg log_msg(loc, &name_, lvl, to_string_view(buf));
            sink_it_(log_msg);
        }
        SPDLOG_CATCH_AND_HANDLE
    }

    template<typename T>
    void trace(const T &msg)
    {
        log(level::trace, msg);
    }

    template<typename T>
    void debug(const T &msg)
    {
        log(level::debug, msg);
    }

    template<typename T>
    void info(const T &msg)
    {
        log(level::info, msg);
    }

    template<typename T>
    void warn(const T &msg)
    {
        log(level::warn, msg);
    }

    template<typename T>
    void error(const T &msg)
    {
        log(level::err, msg);
    }

    template<typename T>
    void critical(const T &msg)
    {
        log(level::critical, msg);
    }

    bool should_log(level::level_enum msg_level) const
    {
        return msg_level >= level_.load(std::memory_order_relaxed);
    }

    void set_level(level::level_enum log_level)
    {
        level_.store(log_level);
    }

    static level::level_enum default_level()
    {
        return static_cast<spdlog::level::level_enum>(SPDLOG_ACTIVE_LEVEL);
    }

    level::level_enum level() const
    {
        return static_cast<spdlog::level::level_enum>(level_.load(std::memory_order_relaxed));
    }

    const std::string &name() const
    {
        return name_;
    }

    // set formatting for the sinks in this logger.
    // each sink will get a seperate instance of the formatter object.
    void set_formatter(std::unique_ptr<formatter> f)
    {
        for (auto &sink : sinks_)
        {
            sink->set_formatter(f->clone());
        }
    }

    void set_pattern(std::string pattern, pattern_time_type time_type = pattern_time_type::local)
    {
        auto new_formatter = details::make_unique<spdlog::pattern_formatter>(std::move(pattern), time_type);
        set_formatter(std::move(new_formatter));
    }

    // flush functions
    void flush()
    {
        try
        {
            flush_();
        }
        SPDLOG_CATCH_AND_HANDLE
    }

    void flush_on(level::level_enum log_level)
    {
        flush_level_.store(log_level);
    }

    level::level_enum flush_level() const
    {
        return static_cast<spdlog::level::level_enum>(flush_level_.load(std::memory_order_relaxed));
    }

    // sinks
    const std::vector<sink_ptr> &sinks() const
    {
        return sinks_;
    }

    std::vector<sink_ptr> &sinks()
    {
        return sinks_;
    }

    // error handler
    void set_error_handler(log_err_handler err_handler)
    {
        err_handler_ = std::move(err_handler);
    }

    log_err_handler error_handler() const
    {
        return err_handler_;
    }

    // create new logger with same sinks and configuration.
    virtual std::shared_ptr<logger> clone(std::string logger_name)
    {
        auto cloned = std::make_shared<spdlog::logger>(std::move(logger_name), sinks_.begin(), sinks_.end());
        cloned->set_level(this->level());
        cloned->flush_on(this->flush_level());
        cloned->set_error_handler(this->error_handler());
        return cloned;
    }


protected:
    virtual void sink_it_(details::log_msg &msg)
    {
#if defined(SPDLOG_ENABLE_MESSAGE_COUNTER)
        incr_msg_counter_(msg);
#endif
        for (auto &sink : sinks_)
        {
            if (sink->should_log(msg.level))
            {
                sink->log(msg);
            }
        }

        if (should_flush_(msg))
        {
            flush_();
        }
    }

    virtual void flush_()
    {
        for (auto &sink : sinks_)
        {
            sink->flush();
        }
    }

    bool should_flush_(const details::log_msg &msg)
    {
        auto flush_level = flush_level_.load(std::memory_order_relaxed);
        return (msg.level >= flush_level) && (msg.level != level::off);
    }

    // default error handler.
    // print the error to stderr with the max rate of 1 message/minute.
    void default_err_handler_(const std::string &msg)
    {
        auto now = time(nullptr);
        if (now - last_err_time_ < 60)
        {
            return;
        }
        last_err_time_ = now;
        auto tm_time = details::os::localtime(now);
        char date_buf[100];
        std::strftime(date_buf, sizeof(date_buf), "%Y-%m-%d %H:%M:%S", &tm_time);
        fmt::print(stderr, "[*** LOG ERROR ***] [{}] [{}] {}\n", date_buf, name(), msg);
    }

    // increment the message count (only if defined(SPDLOG_ENABLE_MESSAGE_COUNTER))
    void incr_msg_counter_(details::log_msg &msg)
    {
        msg.msg_id = msg_counter_.fetch_add(1, std::memory_order_relaxed);
    }

    const std::string name_;
    std::vector<sink_ptr> sinks_;
    spdlog::level_t level_{spdlog::logger::default_level()};
    spdlog::level_t flush_level_{level::off};
    log_err_handler err_handler_{[this](const std::string &msg) { this->default_err_handler_(msg); }};
    std::atomic<time_t> last_err_time_{0};
    std::atomic<size_t> msg_counter_{1};
};
} // namespace spdlog