dir_watcher.hpp

// By Emil Ernerfeldt 2014-2016
// LICENSE:
//   This software is dual-licensed to the public domain and under the following
//   license: you are granted a perpetual, irrevocable license to copy, modify,
//   publish, and distribute this file as you see fit.
// HISTORY
//   2014 - Created for Ghostel
//   2016 - revived for PipeDreams
//   2016 - added to emilib

#pragma once

#include <ctime>
#include <set>
#include <string>
#include <vector>

struct kevent;

namespace emilib {

class DirWatcher
{
public:
    explicit DirWatcher(std::string dir);
    ~DirWatcher();

    std::vector<std::string> poll_files();

private:
    DirWatcher(DirWatcher&) = delete;
    DirWatcher(DirWatcher&&) = delete;
    DirWatcher& operator=(DirWatcher&) = delete;
    DirWatcher& operator=(DirWatcher&&) = delete;

    struct File
    {
        std::string       path; // Full, absolute path.
        std::string       file_name;
        time_t            mtime;
        bool              is_dir;
        std::vector<File> children;
        int               fd = -1; // File descriptor
    };

    void create();
    void add_dir(std::string dir);
    void destroy();

    void add_dir(File& dir);
    void poll_files_in(std::vector<std::string>& changes, File& dir);
    void rescan(std::vector<std::string>& changes, File& dir);

    void add_kevent(File& file);

    void close_file(File& file);

private:
    const std::string   _dir;
    bool                _recursive   = true;
    bool                _check_files = true;
    std::vector<File>   _dirs;
    std::vector<kevent> _events;
    int                 _kqueue;
};

// -------------------------------------------------------

class DelayedDirWatcher
{
public:
    DelayedDirWatcher(std::string dir, unsigned frame_delay = 6);

    std::vector<std::string> poll_files();

private:
    const unsigned        _frame_delay;
    DirWatcher            _dir_watcher;
    std::set<std::string> _dirty_files;
    unsigned              _frames_since_last_change = 0;
};

} // namespace emilib