logger.h

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// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)
 
#pragma once
 
// Thread safe logger (except for 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 for different format per sink.
 
#include <spdlog/common.h>
#include <spdlog/details/log_msg.h>
#include <spdlog/details/backtracer.h>
 
#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
#ifndef _WIN32
#error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
#endif
#include <spdlog/details/os.h>
#endif
 
#include <vector>
 
#ifndef SPDLOG_NO_EXCEPTIONS
#define SPDLOG_LOGGER_CATCH(location)                                                                                     \
    catch (const std::exception& ex)                                                                                      \
    {                                                                                                                     \
        if (location.filename)                                                                                            \
        {                                                                                                                 \
            err_handler_(fmt_lib::format(SPDLOG_FMT_STRING("{} [{}({})]"), ex.what(), location.filename, location.line)); \
        }                                                                                                                 \
        else                                                                                                              \
        {                                                                                                                 \
            err_handler_(ex.what());                                                                                      \
        }                                                                                                                 \
    }                                                                                                                     \
    catch (...)                                                                                                           \
    {                                                                                                                     \
        err_handler_("Rethrowing unknown exception in logger");                                                           \
        throw;                                                                                                            \
    }
#else
#define SPDLOG_LOGGER_CATCH(location)
#endif
 
namespace spdlog
{
 
    class SPDLOG_API logger
    {
    public:
        // Empty logger
        explicit logger(std::string name)
            : name_(std::move(name)), sinks_()
        {
        }
 
        // Logger with range on sinks
        template <typename It>
        logger(std::string name, It begin, It end)
            : name_(std::move(name)), sinks_(begin, end)
        {
        }
 
        // Logger with single sink
        logger(std::string name, sink_ptr single_sink)
            : logger(std::move(name), {std::move(single_sink)})
        {
        }
 
        // Logger with sinks init list
        logger(std::string name, sinks_init_list sinks)
            : logger(std::move(name), sinks.begin(), sinks.end())
        {
        }
 
        virtual ~logger() = default;
 
        logger(const logger& other);
        logger(logger&& other) SPDLOG_NOEXCEPT;
        logger& operator=(logger other) SPDLOG_NOEXCEPT;
        void    swap(spdlog::logger& other) SPDLOG_NOEXCEPT;
 
        template <typename... Args>
        void log(source_loc loc, level::level_enum lvl, format_string_t<Args...> fmt, Args&&... args)
        {
            log_(loc, lvl, details::to_string_view(fmt), std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void log(level::level_enum lvl, format_string_t<Args...> fmt, Args&&... args)
        {
            log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
        }
 
        template <typename T>
        void log(level::level_enum lvl, const T& msg)
        {
            log(source_loc{}, lvl, msg);
        }
 
        // T cannot be statically converted to format string (including string_view/wstring_view)
        template <class T, typename std::enable_if<!is_convertible_to_any_format_string<const T&>::value, int>::type = 0>
        void log(source_loc loc, level::level_enum lvl, const T& msg)
        {
            log(loc, lvl, "{}", msg);
        }
 
        void log(log_clock::time_point log_time, source_loc loc, level::level_enum lvl, string_view_t msg)
        {
            bool log_enabled       = should_log(lvl);
            bool traceback_enabled = tracer_.enabled();
            if (!log_enabled && !traceback_enabled)
            {
                return;
            }
 
            details::log_msg log_msg(log_time, loc, name_, lvl, msg);
            log_it_(log_msg, log_enabled, traceback_enabled);
        }
 
        void log(source_loc loc, level::level_enum lvl, string_view_t msg)
        {
            bool log_enabled       = should_log(lvl);
            bool traceback_enabled = tracer_.enabled();
            if (!log_enabled && !traceback_enabled)
            {
                return;
            }
 
            details::log_msg log_msg(loc, name_, lvl, msg);
            log_it_(log_msg, log_enabled, traceback_enabled);
        }
 
        void log(level::level_enum lvl, string_view_t msg)
        {
            log(source_loc{}, lvl, msg);
        }
 
        template <typename... Args>
        void trace(format_string_t<Args...> fmt, Args&&... args)
        {
            log(level::trace, fmt, std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void debug(format_string_t<Args...> fmt, Args&&... args)
        {
            log(level::debug, fmt, std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void info(format_string_t<Args...> fmt, Args&&... args)
        {
            log(level::info, fmt, std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void warn(format_string_t<Args...> fmt, Args&&... args)
        {
            log(level::warn, fmt, std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void error(format_string_t<Args...> fmt, Args&&... args)
        {
            log(level::err, fmt, std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void critical(format_string_t<Args...> fmt, Args&&... args)
        {
            log(level::critical, fmt, std::forward<Args>(args)...);
        }
 
#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
        template <typename... Args>
        void log(source_loc loc, level::level_enum lvl, wformat_string_t<Args...> fmt, Args&&... args)
        {
            log_(loc, lvl, details::to_string_view(fmt), std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void log(level::level_enum lvl, wformat_string_t<Args...> fmt, Args&&... args)
        {
            log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
        }
 
        void log(log_clock::time_point log_time, source_loc loc, level::level_enum lvl, wstring_view_t msg)
        {
            bool log_enabled       = should_log(lvl);
            bool traceback_enabled = tracer_.enabled();
            if (!log_enabled && !traceback_enabled)
            {
                return;
            }
 
            memory_buf_t buf;
            details::os::wstr_to_utf8buf(wstring_view_t(msg.data(), msg.size()), buf);
            details::log_msg log_msg(log_time, loc, name_, lvl, string_view_t(buf.data(), buf.size()));
            log_it_(log_msg, log_enabled, traceback_enabled);
        }
 
        void log(source_loc loc, level::level_enum lvl, wstring_view_t msg)
        {
            bool log_enabled       = should_log(lvl);
            bool traceback_enabled = tracer_.enabled();
            if (!log_enabled && !traceback_enabled)
            {
                return;
            }
 
            memory_buf_t buf;
            details::os::wstr_to_utf8buf(wstring_view_t(msg.data(), msg.size()), buf);
            details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
            log_it_(log_msg, log_enabled, traceback_enabled);
        }
 
        void log(level::level_enum lvl, wstring_view_t msg)
        {
            log(source_loc{}, lvl, msg);
        }
 
        template <typename... Args>
        void trace(wformat_string_t<Args...> fmt, Args&&... args)
        {
            log(level::trace, fmt, std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void debug(wformat_string_t<Args...> fmt, Args&&... args)
        {
            log(level::debug, fmt, std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void info(wformat_string_t<Args...> fmt, Args&&... args)
        {
            log(level::info, fmt, std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void warn(wformat_string_t<Args...> fmt, Args&&... args)
        {
            log(level::warn, fmt, std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void error(wformat_string_t<Args...> fmt, Args&&... args)
        {
            log(level::err, fmt, std::forward<Args>(args)...);
        }
 
        template <typename... Args>
        void critical(wformat_string_t<Args...> fmt, Args&&... args)
        {
            log(level::critical, fmt, std::forward<Args>(args)...);
        }
#endif
 
        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);
        }
 
        // return true logging is enabled for the given level.
        bool should_log(level::level_enum msg_level) const
        {
            return msg_level >= level_.load(std::memory_order_relaxed);
        }
 
        // return true if backtrace logging is enabled.
        bool should_backtrace() const
        {
            return tracer_.enabled();
        }
 
        void set_level(level::level_enum log_level);
 
        level::level_enum level() const;
 
        const std::string& name() const;
 
        // set formatting for the sinks in this logger.
        // each sink will get a separate instance of the formatter object.
        void set_formatter(std::unique_ptr<formatter> f);
 
        // set formatting for the sinks in this logger.
        // equivalent to
        //     set_formatter(make_unique<pattern_formatter>(pattern, time_type))
        // Note: each sink will get a new instance of a formatter object, replacing the old one.
        void set_pattern(std::string pattern, pattern_time_type time_type = pattern_time_type::local);
 
        // backtrace support.
        // efficiently store all debug/trace messages in a circular buffer until needed for debugging.
        void enable_backtrace(size_t n_messages);
        void disable_backtrace();
        void dump_backtrace();
 
        // flush functions
        void              flush();
        void              flush_on(level::level_enum log_level);
        level::level_enum flush_level() const;
 
        // sinks
        const std::vector<sink_ptr>& sinks() const;
 
        std::vector<sink_ptr>& sinks();
 
        // error handler
        void set_error_handler(err_handler);
 
        // create new logger with same sinks and configuration.
        virtual std::shared_ptr<logger> clone(std::string logger_name);
 
    protected:
        std::string           name_;
        std::vector<sink_ptr> sinks_;
        spdlog::level_t       level_{level::info};
        spdlog::level_t       flush_level_{level::off};
        err_handler           custom_err_handler_{nullptr};
        details::backtracer   tracer_;
 
        // common implementation for after templated public api has been resolved
        template <typename... Args>
        void log_(source_loc loc, level::level_enum lvl, string_view_t fmt, Args&&... args)
        {
            bool log_enabled       = should_log(lvl);
            bool traceback_enabled = tracer_.enabled();
            if (!log_enabled && !traceback_enabled)
            {
                return;
            }
            SPDLOG_TRY
            {
                memory_buf_t buf;
#ifdef SPDLOG_USE_STD_FORMAT
                fmt_lib::vformat_to(std::back_inserter(buf), fmt, fmt_lib::make_format_args(std::forward<Args>(args)...));
#else
                fmt::vformat_to(fmt::appender(buf), fmt, fmt::make_format_args(std::forward<Args>(args)...));
#endif
 
                details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
                log_it_(log_msg, log_enabled, traceback_enabled);
            }
            SPDLOG_LOGGER_CATCH(loc)
        }
 
#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
        template <typename... Args>
        void log_(source_loc loc, level::level_enum lvl, wstring_view_t fmt, Args&&... args)
        {
            bool log_enabled       = should_log(lvl);
            bool traceback_enabled = tracer_.enabled();
            if (!log_enabled && !traceback_enabled)
            {
                return;
            }
            SPDLOG_TRY
            {
                // format to wmemory_buffer and convert to utf8
                wmemory_buf_t wbuf;
                fmt_lib::vformat_to(
                    std::back_inserter(wbuf), fmt, fmt_lib::make_format_args<fmt_lib::wformat_context>(std::forward<Args>(args)...));
 
                memory_buf_t buf;
                details::os::wstr_to_utf8buf(wstring_view_t(wbuf.data(), wbuf.size()), buf);
                details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
                log_it_(log_msg, log_enabled, traceback_enabled);
            }
            SPDLOG_LOGGER_CATCH(loc)
        }
#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
 
        // log the given message (if the given log level is high enough),
        // and save backtrace (if backtrace is enabled).
        void         log_it_(const details::log_msg& log_msg, bool log_enabled, bool traceback_enabled);
        virtual void sink_it_(const details::log_msg& msg);
        virtual void flush_();
        void         dump_backtrace_();
        bool         should_flush_(const details::log_msg& msg);
 
        // handle errors during logging.
        // default handler prints the error to stderr at max rate of 1 message/sec.
        void err_handler_(const std::string& msg);
    };
 
    void swap(logger& a, logger& b);
 
} // namespace spdlog
 
#ifdef SPDLOG_HEADER_ONLY
#include "logger-inl.h"
#endif