qt_sinks.h

// Copyright(c) 2015-present, Gabi Melman, mguludag and spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)

#pragma once

//
// Custom sink for QPlainTextEdit or QTextEdit and its childs(QTextBrowser...
// etc) Building and using requires Qt library.
//
// Warning: the qt_sink won't be notified if the target widget is destroyed.
// If the widget's lifetime can be shorter than the logger's one, you should provide some permanent QObject,
// and then use a standard signal/slot.
//

#include "spdlog/common.h"
#include "spdlog/details/log_msg.h"
#include "spdlog/details/synchronous_factory.h"
#include "spdlog/sinks/base_sink.h"
#include <array>

#include <QTextEdit>
#include <QPlainTextEdit>

//
// qt_sink class
//
namespace spdlog {
namespace sinks {
template<typename Mutex>
class qt_sink : public base_sink<Mutex>
{
public:
    qt_sink(QObject *qt_object, std::string meta_method)
        : qt_object_(qt_object)
        , meta_method_(std::move(meta_method))
    {
        if (!qt_object_)
        {
            throw_spdlog_ex("qt_sink: qt_object is null");
        }
    }

    ~qt_sink()
    {
        flush_();
    }

protected:
    void sink_it_(const details::log_msg &msg) override
    {
        memory_buf_t formatted;
        base_sink<Mutex>::formatter_->format(msg, formatted);
        const string_view_t str = string_view_t(formatted.data(), formatted.size());
        QMetaObject::invokeMethod(qt_object_, meta_method_.c_str(), Qt::AutoConnection,
            Q_ARG(QString, QString::fromUtf8(str.data(), static_cast<int>(str.size())).trimmed()));
    }

    void flush_() override {}

private:
    QObject *qt_object_ = nullptr;
    std::string meta_method_;
};

// QT color sink to QTextEdit.
// Color location is determined by the sink log pattern like in the rest of spdlog sinks.
// Colors can be modified if needed using sink->set_color(level, qtTextCharFormat).
// max_lines is the maximum number of lines that the sink will hold before removing the oldest lines.
// Note: Only ascii (latin1) is supported by this sink.
template<typename Mutex>
class qt_color_sink : public base_sink<Mutex>
{
public:
    qt_color_sink(QTextEdit *qt_text_edit, int max_lines)
        : qt_text_edit_(qt_text_edit)
        , max_lines_(max_lines)
    {
        if (!qt_text_edit_)
        {
            throw_spdlog_ex("qt_color_text_sink: text_edit is null");
        }

        default_color_ = qt_text_edit_->currentCharFormat();
        // set colors
        QTextCharFormat format;
        // trace
        format.setForeground(Qt::gray);
        colors_.at(level::trace) = format;
        // debug
        format.setForeground(Qt::cyan);
        colors_.at(level::debug) = format;
        // info
        format.setForeground(Qt::green);
        colors_.at(level::info) = format;
        // warn
        format.setForeground(Qt::yellow);
        colors_.at(level::warn) = format;
        // err
        format.setForeground(Qt::red);
        colors_.at(level::err) = format;
        // critical
        format.setForeground(Qt::white);
        format.setBackground(Qt::red);
        colors_.at(level::critical) = format;
    }

    ~qt_color_sink()
    {
        flush_();
    }

    void set_default_color(QTextCharFormat format)
    {
        // std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
        default_color_ = format;
    }

    void set_level_color(level::level_enum color_level, QTextCharFormat format)
    {
        // std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
        colors_.at(static_cast<size_t>(color_level)) = format;
    }

    QTextCharFormat &get_level_color(level::level_enum color_level)
    {
        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
        return colors_.at(static_cast<size_t>(color_level));
    }

    QTextCharFormat &get_default_color()
    {
        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
        return default_color_;
    }

protected:
    struct invoke_params
    {
        invoke_params(int max_lines, QTextEdit *q_text_edit, QString payload, QTextCharFormat default_color, QTextCharFormat level_color,
            int color_range_start, int color_range_end)
            : max_lines(max_lines)
            , q_text_edit(q_text_edit)
            , payload(std::move(payload))
            , default_color(default_color)
            , level_color(level_color)
            , color_range_start(color_range_start)
            , color_range_end(color_range_end)
        {}
        int max_lines;
        QTextEdit *q_text_edit;
        QString payload;
        QTextCharFormat default_color;
        QTextCharFormat level_color;
        int color_range_start;
        int color_range_end;
    };

    void sink_it_(const details::log_msg &msg) override
    {
        memory_buf_t formatted;
        base_sink<Mutex>::formatter_->format(msg, formatted);

        const string_view_t str = string_view_t(formatted.data(), formatted.size());
        // apply the color to the color range in the formatted message.
        auto payload = QString::fromLatin1(str.data(), static_cast<int>(str.size()));

        invoke_params params{max_lines_,             // max lines
            qt_text_edit_,                           // text edit to append to
            std::move(payload),                      // text to append
            default_color_,                          // default color
            colors_.at(msg.level),                   // color to apply
            static_cast<int>(msg.color_range_start), // color range start
            static_cast<int>(msg.color_range_end)};  // color range end

        QMetaObject::invokeMethod(
            qt_text_edit_, [params]() { invoke_method_(params); }, Qt::AutoConnection);
    }

    void flush_() override {}

    // Add colored text to the text edit widget. This method is invoked in the GUI thread.
    // It is a static method to ensure that it is handled correctly even if the sink is destroyed prematurely
    // before it is invoked.

    static void invoke_method_(invoke_params params)
    {
        auto *document = params.q_text_edit->document();
        QTextCursor cursor(document);

        // remove first blocks if number of blocks exceeds max_lines
        while (document->blockCount() > params.max_lines)
        {
            cursor.select(QTextCursor::BlockUnderCursor);
            cursor.removeSelectedText();
            cursor.deleteChar(); // delete the newline after the block
        }

        cursor.movePosition(QTextCursor::End);
        cursor.setCharFormat(params.default_color);

        // if color range not specified or not not valid, just append the text with default color
        if (params.color_range_end <= params.color_range_start)
        {
            cursor.insertText(params.payload);
            return;
        }

        // insert the text before the color range
        cursor.insertText(params.payload.left(params.color_range_start));

        // insert the colorized text
        cursor.setCharFormat(params.level_color);
        cursor.insertText(params.payload.mid(params.color_range_start, params.color_range_end - params.color_range_start));

        // insert the text after the color range with default format
        cursor.setCharFormat(params.default_color);
        cursor.insertText(params.payload.mid(params.color_range_end));
    }

    QTextEdit *qt_text_edit_;
    int max_lines_;
    QTextCharFormat default_color_;
    std::array<QTextCharFormat, level::n_levels> colors_;
};

#include "spdlog/details/null_mutex.h"
#include <mutex>

using qt_sink_mt = qt_sink<std::mutex>;
using qt_sink_st = qt_sink<details::null_mutex>;
using qt_color_sink_mt = qt_color_sink<std::mutex>;
using qt_color_sink_st = qt_color_sink<details::null_mutex>;
} // namespace sinks

//
// Factory functions
//

// log to QTextEdit
template<typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> qt_logger_mt(const std::string &logger_name, QTextEdit *qt_object, const std::string &meta_method = "append")
{
    return Factory::template create<sinks::qt_sink_mt>(logger_name, qt_object, meta_method);
}

template<typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> qt_logger_st(const std::string &logger_name, QTextEdit *qt_object, const std::string &meta_method = "append")
{
    return Factory::template create<sinks::qt_sink_st>(logger_name, qt_object, meta_method);
}

// log to QPlainTextEdit
template<typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> qt_logger_mt(
    const std::string &logger_name, QPlainTextEdit *qt_object, const std::string &meta_method = "appendPlainText")
{
    return Factory::template create<sinks::qt_sink_mt>(logger_name, qt_object, meta_method);
}

template<typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> qt_logger_st(
    const std::string &logger_name, QPlainTextEdit *qt_object, const std::string &meta_method = "appendPlainText")
{
    return Factory::template create<sinks::qt_sink_st>(logger_name, qt_object, meta_method);
}
// log to QObject
template<typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> qt_logger_mt(const std::string &logger_name, QObject *qt_object, const std::string &meta_method)
{
    return Factory::template create<sinks::qt_sink_mt>(logger_name, qt_object, meta_method);
}

template<typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> qt_logger_st(const std::string &logger_name, QObject *qt_object, const std::string &meta_method)
{
    return Factory::template create<sinks::qt_sink_st>(logger_name, qt_object, meta_method);
}

// log to QTextEdit with colorize output
template<typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> qt_color_logger_mt(const std::string &logger_name, QTextEdit *qt_text_edit, int max_lines)
{
    return Factory::template create<sinks::qt_color_sink_mt>(logger_name, qt_text_edit, max_lines);
}

template<typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> qt_color_logger_st(const std::string &logger_name, QTextEdit *qt_text_edit, int max_lines)
{
    return Factory::template create<sinks::qt_color_sink_st>(logger_name, qt_text_edit, max_lines);
}

} // namespace spdlog