Formatter.h

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#pragma once
 
#include "Filter.h"
#include "LogLevel.h"
 
#include <iomanip>
#include <iosfwd>
#ifdef THREAD_SAFE
#include <thread>
#endif
 
namespace carl::logging {
 
/**
 * Formats a log messages.
 */
class Formatter {
    /// Width of the longest channel.
    std::size_t channelwidth = 10;
public:
    /// Print information like log level, file etc.
    bool printInformation = true;
 
    virtual ~Formatter() noexcept = default;
 
    /**
     * Extracts the maximum width of a channel to optimize the formatting.
     * @param f Filter.
     */
    virtual void configure(const Filter& f) noexcept {
        for (const auto& t: f.data()) {
            if (t.first.size() > channelwidth) channelwidth = t.first.size();
        }
    }
    /**
     * Prints the prefix of a log message, i.e. everything that goes before the message given by the user, to the output stream.
     * @param os Output stream.
     * @param channel Channel name.
     * @param level LogLevel.
     * @param info Auxiliary information.
     */
    virtual void prefix(std::ostream& os, const std::string& channel, LogLevel level, const RecordInfo& info) {
        if (!printInformation) return;
        os.fill(' ');
#ifdef THREAD_SAFE
        os << std::this_thread::get_id() << " ";
#endif
        os << level << " ";
 
        std::string filename(carl::basename(info.filename));
        std::size_t spacing = 1;
        if (channelwidth + 15 > channel.size() + filename.size()) {
            spacing = channelwidth + 15 - channel.size() - filename.size();
        }
        os << channel << std::string(spacing, ' ') << filename << ":" << std::left << std::setw(4) << info.line << " ";
        os << std::resetiosflags(std::ios::adjustfield);
        if (!info.func.empty()) {
            os << info.func << "(): ";
        }
    }
 
    /**
     * Prints the suffix of a log message, i.e. everything that goes after the message given by the user, to the output stream.
     * Usually, this is only a newline.
     * @param os Output stream.
     */
    virtual void suffix(std::ostream& os) {
        os << std::endl;
    }
};
 
}