FileHelpers.hpp

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#pragma once
 
#include <atomic>
#include <filesystem>
#include <fstream>
#include <regex>
#include <string>
#include <sys/inotify.h>
#include <thread>
#include <vector>

inline std::vector<std::string> findFromFile(const std::filesystem::path &filePath, const std::string &pattern,
                                             std::string &lastWord)
{
    const std::regex regExp(pattern);
    std::ifstream inFile(filePath);
    std::vector<std::string> matchedLines;
 
    std::string readLine;
    while (getline(inFile, readLine))
    {
        if (std::regex_search(readLine, regExp))
        {
            matchedLines.push_back(readLine);
        }
    }
 
    if (!matchedLines.empty())
    {
        auto pos = matchedLines.front().find_last_of(' ');
        if (pos != std::string::npos && pos != matchedLines.front().size())
        {
            lastWord = matchedLines.front().substr(pos + 1);
        }
    }
 
    return matchedLines;
}

inline std::vector<std::string> findFromFile(const std::filesystem::path &filePath, const std::string &pattern)
{
    std::string lastWord;
    return findFromFile(filePath, pattern, lastWord);
}

using FNotifyCallback = std::function<void(const void *)>;

class FileMonitor {
  private:
    int _fDescriptor{-1};
    int _wDescriptor{-1};
    std::filesystem::path _filePath;
    FNotifyCallback _notifyCallback;
    uint32_t _notifyEvents;
    const void *_userPtr = nullptr;

    std::unique_ptr<std::jthread> _thread;
 
    void threadFunc(const std::stop_token &stopToken) const noexcept;
 
  public:
    explicit FileMonitor(std::filesystem::path filePath, uint32_t notifyEvents = IN_MODIFY);

    FileMonitor(const FileMonitor & /*unused*/) = delete;

    FileMonitor(FileMonitor && /*unused*/) = delete;

    FileMonitor &operator=(FileMonitor /*unused*/) = delete;

    FileMonitor &operator=(FileMonitor && /*unused*/) = delete;
 
    [[nodiscard]] FNotifyCallback notifyCallback() const { return _notifyCallback; }
    void notifyCallback(FNotifyCallback func) { _notifyCallback = std::move(func); }

    void userPtr(const void *ptr) { _userPtr = ptr; }

    ~FileMonitor();
};