LogWidget.h

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// ----------------------------------------------------------------------------
// -                        CloudViewer: www.cloudViewer.org                  -
// ----------------------------------------------------------------------------
// Copyright (c) 2018-2024 www.cloudViewer.org
// SPDX-License-Identifier: MIT
// ----------------------------------------------------------------------------
 
#pragma once
 
#include <QtGui>
#include <QtWidgets>
#include <fstream>
#include <iostream>
 
namespace cloudViewer {
 
template <class Elem = char, class Tr = std::char_traits<Elem>>
class StandardOutputRedirector : public std::basic_streambuf<Elem, Tr> {
    typedef void (*cb_func_ptr)(const Elem*, std::streamsize count, void* data);
 
public:
    StandardOutputRedirector(std::ostream& stream,
                             cb_func_ptr cb_func,
                             void* data)
        : stream_(stream), cb_func_(cb_func), data_(data) {
        buf_ = stream_.rdbuf(this);
    }
 
    ~StandardOutputRedirector() { stream_.rdbuf(buf_); }
 
    std::streamsize xsputn(const Elem* ptr, std::streamsize count) {
        cb_func_(ptr, count, data_);
        return count;
    }
 
    typename Tr::int_type overflow(typename Tr::int_type v) {
        Elem ch = Tr::to_char_type(v);
        cb_func_(&ch, 1, data_);
        return Tr::not_eof(v);
    }
 
private:
    std::basic_ostream<Elem, Tr>& stream_;
    std::streambuf* buf_;
    cb_func_ptr cb_func_;
    void* data_;
};
 
class LogWidget : public QWidget {
public:
    LogWidget(QWidget* parent, const int max_num_blocks = 100000);
    ~LogWidget();
 
    void Append(const std::string& text);
    void Flush();
    void Clear();
 
private:
    static void Update(const char* text,
                       std::streamsize count,
                       void* text_box_ptr);
 
    void SaveLog();
 
    QMutex mutex_;
    std::string text_queue_;
    // Buffer for CVLog output (accumulates until newline)
    std::string cvlog_buffer_;
    QPlainTextEdit* text_box_;
    std::ofstream log_file_;
    StandardOutputRedirector<char, std::char_traits<char>>* cout_redirector_;
    StandardOutputRedirector<char, std::char_traits<char>>* cerr_redirector_;
    StandardOutputRedirector<char, std::char_traits<char>>* clog_redirector_;
};
 
}  // namespace cloudViewer