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 children (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 <QPlainTextEdit>
#include <QTextEdit>

//
// 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. By default, only ascii (latin1) is supported by this sink. Set is_utf8 to true if utf8
// support is needed.
template <typename Mutex>
class qt_color_sink : public base_sink<Mutex> {
public:
    qt_color_sink(QTextEdit *qt_text_edit,
                  int max_lines,
                  bool dark_colors = false,
                  bool is_utf8 = false)
        : qt_text_edit_(qt_text_edit),
          max_lines_(max_lines),
          is_utf8_(is_utf8) {
        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(dark_colors ? Qt::darkGray : Qt::gray);
        colors_.at(level::trace) = format;
        // debug
        format.setForeground(dark_colors ? Qt::darkCyan : Qt::cyan);
        colors_.at(level::debug) = format;
        // info
        format.setForeground(dark_colors ? Qt::darkGreen : Qt::green);
        colors_.at(level::info) = format;
        // warn
        format.setForeground(dark_colors ? Qt::darkYellow : 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.
        QString payload;
        int color_range_start = static_cast<int>(msg.color_range_start);
        int color_range_end = static_cast<int>(msg.color_range_end);
        if (is_utf8_) {
            payload = QString::fromUtf8(str.data(), static_cast<int>(str.size()));
            // convert color ranges from byte index to character index.
            if (msg.color_range_start < msg.color_range_end) {
                color_range_start = QString::fromUtf8(str.data(), msg.color_range_start).size();
                color_range_end = QString::fromUtf8(str.data(), msg.color_range_end).size();
            }
        } else {
            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
                             color_range_start,      // color range start
                             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_;
    bool is_utf8_;
    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 colorized 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,
                                                  bool is_utf8 = false) {
    return Factory::template create<sinks::qt_color_sink_mt>(logger_name, qt_text_edit, max_lines,
                                                             false, is_utf8);
}

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,
                                                  bool is_utf8 = false) {
    return Factory::template create<sinks::qt_color_sink_st>(logger_name, qt_text_edit, max_lines,
                                                             false, is_utf8);
}

}  // namespace spdlog