files_dir_listen.cpp

This code listens to changes to a directory and maintains a list of all JSON files in the directory.

See also

files::FileWatcher

/*
 * ======================================================================================
 *  __    ____  __  __  ____  ___
 * (  )  (_  _)(  \/  )( ___)/ __)
 *  )(__  _)(_  )    (  )__) \__ \
 * (____)(____)(_/\/\_)(____)(___/
 *
 *  This file is part of the Limes open source library and is licensed under the terms of the GNU Public License.
 *
 *  Commercial licenses are available; contact the maintainers at ben.the.vining@gmail.com to inquire for details.
 *
 * ======================================================================================
 */
 
#include <lfilesystem/lfilesystem.h>
#include <vector>
 
struct JSONWatcher final : public limes::files::FileWatcher
{
    explicit JSONWatcher (const limes::files::Directory& dir)
        : limes::files::FileWatcher (dir), directory (dir)
    { }
 
    std::vector<limes::files::File> jsonFiles;
    const limes::files::Directory   directory;
 
    void fileCreated (const limes::files::FilesystemEntry& file) final
    {
        if (! directory.contains (file))
            return;
 
        if (const auto fileObj = file.getFileObject())
        {
            if (fileObj->hasFileExtension (".json"))
                jsonFiles.emplace_back (*fileObj);
        }
    }
 
    void fileDeleted (const limes::files::FilesystemEntry& file) final
    {
        jsonFiles.erase (std::find_if (jsonFiles.begin(), jsonFiles.end(),
                                       [p = file.getAbsolutePath()] (limes::files::File& f)
                                       {
                                           return f.getAbsolutePath() == p;
                                       }));
    }
 
    void fileMoved (const limes::files::FilesystemEntry& file) final
    {
        if (! directory.contains (file))
        {
            fileDeleted (file);
            return;
        }
 
        if (const auto fileObj = file.getFileObject())
        {
            if (! fileObj->hasFileExtension (".json"))
                return;
 
            const auto alreadyInList = (std::find (jsonFiles.begin(),
                                                   jsonFiles.end(),
                                                   *fileObj)
                                        != jsonFiles.end());
 
            if (! alreadyInList)
                jsonFiles.emplace_back (*fileObj);
        }
    }
};
 
const limes::files::Directory dir { "/my/directory" };
 
JSONWatcher watcher { dir };